Computed tomography demonstrates abnormalities of contralateral ear in subjects with unilateral sensorineural hearing loss.

PubMed

Marcus, Sonya; Whitlow, Christopher T; Koonce, James; Zapadka, Michael E; Chen, Michael Y; Williams, Daniel W; Lewis, Meagan; Evans, Adele K

2014-02-01

Prior studies have associated gross inner ear abnormalities with pediatric sensorineural hearing loss (SNHL) using computed tomography (CT). No studies to date have specifically investigated morphologic inner ear abnormalities involving the contralateral unaffected ear in patients with unilateral SNHL. The purpose of this study is to evaluate contralateral inner ear structures of subjects with unilateral SNHL but no grossly abnormal findings on CT. IRB-approved retrospective analysis of pediatric temporal bone CT scans. 97 temporal bone CT scans, previously interpreted as "normal" based upon previously accepted guidelines by board certified neuroradiologists, were assessed using 12 measurements of the semicircular canals, cochlea and vestibule. The control-group consisted of 72 "normal" temporal bone CTs with underlying SNHL in the subject excluded. The study-group consisted of 25 normal-hearing contralateral temporal bones in subjects with unilateral SNHL. Multivariate analysis of covariance (MANCOVA) was then conducted to evaluate for differences between the study and control group. Cochlea basal turn lumen width was significantly greater in magnitude and central lucency of the lateral semicircular canal bony island was significantly lower in density for audiometrically normal ears of subjects with unilateral SNHL compared to controls. Abnormalities of the inner ear were present in the contralateral audiometrically normal ears of subjects with unilateral SNHL. These data suggest that patients with unilateral SNHL may have a more pervasive disease process that results in abnormalities of both ears. The findings of a cochlea basal turn lumen width disparity >5% from "normal" and/or a lateral semicircular canal bony island central lucency disparity of >5% from "normal" may indicate inherent risk to the contralateral unaffected ear in pediatric patients with unilateral sensorineural hearing loss. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Alteration of Duration Mismatch Negativity Induced by Transcranial Magnetic Stimulation Over the Left Parietal Lobe.

PubMed

Oshima, Hirokazu; Shiga, Tetsuya; Niwa, Shin-Ichi; Enomoto, Hiroyuki; Ugawa, Yoshikazu; Yabe, Hirooki

2017-01-01

Mismatch negativity (MMN) is generated by a comparison between an incoming sound and the memory trace of preceding sounds stored in sensory memory without any attention to the sound. N100 (N1) is associated with the afferent response to sound onset and reflects early analysis of stimulus characteristics. MMN generators are present in the temporal and frontal lobe, and N1 generators are present in the temporal lobe. The parietal lobe is involved in MMN generation elicited by a change in duration. The anatomical network connecting these areas, lateralization, and the effect of the side of ear stimulation on MMN remain unknown. Thus, we studied the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) over the left parietal lobe on MMN and N1 in 10 healthy subjects. Low-frequency rTMS over the left parietal lobe decreased the amplitude of MMN following right ear sound stimulation, but the amplitude was unaffected with left ear sound stimulation. We observed no significant changes in the amplitude of N1 or the latency of MMN or N1. These results suggest that low-frequency rTMS over the left parietal lobe modulates the detection of early auditory changes in duration in healthy subjects. Stimulation that is contralateral to the side of the ear experiencing sound may affect the generation of duration MMN more than ipsilateral stimulation. © EEG and Clinical Neuroscience Society (ECNS) 2016.

Monaural or binaural sound deprivation in postlingual hearing loss: Cochlear implant in the worse ear.

PubMed

Canale, Andrea; Dalmasso, Giulia; Dagna, Federico; Lacilla, Michelangelo; Montuschi, Carla; Rosa, Rosalba Di; Albera, Roberto

2016-08-01

To determine whether speech recognition scores (SRS) differ between adults with long-term auditory deprivation in the implanted ear and adults who received cochlear implant (CI) in the nonsound-deprived ear, either for hearing aid-assisted or due to rapidly deteriorating hearing loss. Retrospective study. Speech recognition scores at evaluations (3 and 14 months postimplantation) conducted with CI alone at 60-dB sound pressure level intensity were compared in 15 patients (4 with bilateral severe hearing loss; 11 with asymmetric hearing loss, 7 of which had contralateral hearing aid), all with long-term auditory deprivation (mean duration 16.9 years) (group A), and in 15 other patients with postlingual hearing loss (10 symmetric, 5 asymmetric with bimodal stimulation) (controls, group B). Comparison of mean percentage of correctly recognized words on speech audiometry at 3 and 14 months showed improvement within each group (P < 0.05). Between-group comparison showed no significant difference at 3 (P = 0.17) or 14 months (P = 0.46). Comparison of SRSs in group A (bimodal stimulation [n = 7] and binaural sound deprivation [n = 4]) versus group B showed no significant differences at 3 (bimodal stimulation P = 0.16; binaural sound deprivation P = 0.19) or 14 months (bimodal stimulation P = 0.14; binaural sound deprivation P = 0.82). Speech recognition scores in monaural and binaural sound-deprived ears did not significantly differ from ears with unilateral cochlear implantation in nonsound-deprived ears when tested with CI alone. Improvement in the implanted worse ear indicates that it could be a potential candidate ear for cochlear implantation even when sound deprived. 4. Laryngoscope, 126:1905-1910, 2016. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Contralateral Noise Stimulation Delays P300 Latency in School-Aged Children.

PubMed

Ubiali, Thalita; Sanfins, Milaine Dominici; Borges, Leticia Reis; Colella-Santos, Maria Francisca

2016-01-01

The auditory cortex modulates auditory afferents through the olivocochlear system, which innervates the outer hair cells and the afferent neurons under the inner hair cells in the cochlea. Most of the studies that investigated the efferent activity in humans focused on evaluating the suppression of the otoacoustic emissions by stimulating the contralateral ear with noise, which assesses the activation of the medial olivocochlear bundle. The neurophysiology and the mechanisms involving efferent activity on higher regions of the auditory pathway, however, are still unknown. Also, the lack of studies investigating the effects of noise on human auditory cortex, especially in peadiatric population, points to the need for recording the late auditory potentials in noise conditions. Assessing the auditory efferents in schoolaged children is highly important due to some of its attributed functions such as selective attention and signal detection in noise, which are important abilities related to the development of language and academic skills. For this reason, the aim of the present study was to evaluate the effects of noise on P300 responses of children with normal hearing. P300 was recorded in 27 children aged from 8 to 14 years with normal hearing in two conditions: with and whitout contralateral white noise stimulation. P300 latencies were significantly longer at the presence of contralateral noise. No significant changes were observed for the amplitude values. Contralateral white noise stimulation delayed P300 latency in a group of school-aged children with normal hearing. These results suggest a possible influence of the medial olivocochlear activation on P300 responses under noise condition.

Long-term results of hearing preservation cochlear implant surgery in patients with residual low frequency hearing.

PubMed

Moteki, Hideaki; Nishio, Shin-Ya; Miyagawa, Maiko; Tsukada, Keita; Iwasaki, Satoshi; Usami, Shin-Ichi

2017-05-01

Differences were found between patients with stable hearing and those with progressive hearing loss in the lower frequencies with respect to the rate of progression in the contralateral ear. It is suggested that the electric acoustic stimulation (EAS) can provide improvement in hearing ability over the long-term if residual hearing might be lost to some extent. To evaluate the long-term threshold changes in the low frequency hearing of the implanted ear as compared with the non-implanted ear, and the hearing abilities with EAS along with the extent of residual hearing. Seventeen individuals were enrolled and received the EAS implant with a 24-mm FLEXeas electrode array. Hearing thresholds and speech perception were measured pre- and post-operatively for 1-5 years. Post-operative hearing preservation (HP) rates were calculated using the preservation numerical scale. The average linear regression coefficient for the decline in hearing preservation score was -6.9 for the implanted ear and the patients were subsequently categorized into two groups: those with better than average, stable hearing; and those with worse than average, progressive hearing loss. EAS showed better results than electric stimulation alone, in spite of an absence of speech perception with acoustic stimulation.

Interaural Phase and Level Difference Sensitivity in Low-Frequency Neurons in the Lateral Superior Olive

PubMed Central

Tollin, Daniel J.; Yin, Tom C. T.

2006-01-01

The lateral superior olive (LSO) is believed to encode differences in sound level at the two ears, a cue for azimuthal sound location. Most high-frequency-sensitive LSO neurons are binaural, receiving inputs from both ears. An inhibitory input from the contralateral ear, via the medial nucleus of the trapezoid body (MNTB), and excitatory input from the ipsilateral ear enable level differences to be encoded. However, the classical descriptions of low-frequency-sensitive neurons report primarily monaural cells with no contralateral inhibition. Anatomical and physiological evidence, however, shows that low-frequency LSO neurons receive low-frequency inhibitory input from ipsilateral MNTB, which in turn receives excitatory input from the contralateral cochlear nucleus and low-frequency excitatory input from the ipsilateral cochlear nucleus. Therefore, these neurons would be expected to be binaural with contralateral inhibition. Here, we re-examined binaural interaction in low-frequency (less than ~3 kHz) LSO neurons and phase locking in the MNTB. Phase locking to low-frequency tones in MNTB and ipsilaterally driven LSO neurons with frequency sensitivities < 1.2 kHz was enhanced relative to the auditory nerve. Moreover, most low-frequency LSO neurons exhibited contralateral inhibition: ipsilaterally driven responses were suppressed by raising the level of the contralateral stimulus; most neurons were sensitive to interaural time delays in pure tone and noise stimuli such that inhibition was nearly maximal when the stimuli were presented to the ears in-phase. The data demonstrate that low-frequency LSO neurons of cat are not monaural and can exhibit contralateral inhibition like their high-frequency counterparts. PMID:16291937

Contralateral acoustic stimulation alters the magnitude and phase of distortion product otoacoustic emissions.

PubMed

Deeter, Ryan; Abel, Rebekah; Calandruccio, Lauren; Dhar, Sumitrajit

2009-11-01

Activation of medial olivocochlear efferents through contralateral acoustic stimulation (CAS) has been shown to modulate distortion product otoacoustic emission (DPOAE) level in various ways (enhancement, reduction, or no change). The goal of this study was to investigate the effect of a range of CAS levels on DPOAE fine structure. The 2f(1)-f(2) DPOAE was recorded (f(2)/f(1)=1.22, L(1)=55 dB, and L(2)=40 dB) from eight normal-hearing subjects, using both a frequency-sweep paradigm and a fixed frequency paradigm. Contamination due to the middle ear muscle reflex was avoided by monitoring the magnitude and phase of a probe in the test ear and by monitoring DPOAE stimulus levels throughout testing. Results show modulations in both level and frequency of DPOAE fine structure patterns. Frequency shifts observed at DPOAE level minima could explain reports of enhancement in DPOAE level due to efferent activation. CAS affected the magnitude and phase of the DPOAE component from the characteristic frequency region to a greater extent than the component from the overlap region between the stimulus tones. This differential effect explains the occasional enhancement observed in DPOAE level as well as the frequency shift in fine structure patterns.

Connections from the rat dorsal column nuclei (DCN) to the periaqueductal gray matter (PAG).

PubMed

Barbaresi, Paolo; Mensà, Emanuela

2016-08-01

Electrical stimulation of the dorsal columns (DCs; spinal cord stimulation; SCS) has been proposed to treat chronic neuropathic pain. SCS may activate a dual mechanism that would affect both the spinal cord and supraspinal levels. Stimulation of DCs or DC nuclei (DCN) in animals where neuropathic pain has been induced causes activation of brainstem centers including the periaqueductal gray (PAG), which is involved in the endogenous pain suppression system. Biotinylated dextran-amine (BDA) was iontophoretically injected into the DCN to analyze the ascending projection directed to the PAG. Separate injections into the gracile nucleus (GrN) and the cuneate nucleus (CunN) showed BDA-positive fibers terminating in different regions of the contralateral PAG. GrN-PAG afferents terminated in the caudal and middle portions of PAG-l, whereas CunN-PAG fibers terminated in the middle and rostral portions of PAG-l. Based on the DCN somatotopic map, the GrN sends information to the PAG from the contralateral hindlimb and the tail and the CunN from the contralateral forelimb, shoulder, neck and ear. This somatotopic organization is consistent with earlier electrophysiological and PAG stimulation studies. These fibers could form part of the DCs-brainstem-spinal cord loop, which may be involved in the inhibitory effects of SCS on neuropathic pain. Copyright © 2016. Published by Elsevier Ireland Ltd.

Hearing after congenital deafness: central auditory plasticity and sensory deprivation.

PubMed

Kral, A; Hartmann, R; Tillein, J; Heid, S; Klinke, R

2002-08-01

The congenitally deaf cat suffers from a degeneration of the inner ear. The organ of Corti bears no hair cells, yet the auditory afferents are preserved. Since these animals have no auditory experience, they were used as a model for congenital deafness. Kittens were equipped with a cochlear implant at different ages and electro-stimulated over a period of 2.0-5.5 months using a monopolar single-channel compressed analogue stimulation strategy (VIENNA-type signal processor). Following a period of auditory experience, we investigated cortical field potentials in response to electrical biphasic pulses applied by means of the cochlear implant. In comparison to naive unstimulated deaf cats and normal hearing cats, the chronically stimulated animals showed larger cortical regions producing middle-latency responses at or above 300 microV amplitude at the contralateral as well as the ipsilateral auditory cortex. The cortex ipsilateral to the chronically stimulated ear did not show any signs of reduced responsiveness when stimulating the 'untrained' ear through a second cochlear implant inserted in the final experiment. With comparable duration of auditory training, the activated cortical area was substantially smaller if implantation had been performed at an older age of 5-6 months. The data emphasize that young sensory systems in cats have a higher capacity for plasticity than older ones and that there is a sensitive period for the cat's auditory system.

Effect of cochlear implantation on middle ear function: A three-month prospective study.

PubMed

Wasson, Joseph D; Campbell, Luke; Chambers, Scott; Hampson, Amy; Briggs, Robert J S; O'Leary, Stephen J

2018-05-01

To determine if cochlear implantation has a delayed effect on the middle ear conductive hearing mechanism by measuring laser Doppler vibrometry (LDV) of the tympanic membrane (TM) in both implanted and contralateral control ears preoperatively and 3 months postoperatively, and then comparing the relative change in LDV outcome measures between implanted and control ears. Prospective cohort study. Eleven preoperative adult unilateral cochlear implant recipients in previously unoperated ears with normal anatomy and aerated temporal bones were included in this study. The magnitude and phase angle of umbo velocity transfer function in response to air- conduction (AC) stimulus, and the magnitude of umbo velocity in response to bone- conduction (BC) stimulus were measured in the implant ear and the contralateral control ear preoperatively and 3 months postoperatively and compared. No significant changes in the magnitude or phase angle of TM velocity in response to either AC or BC stimulus were observed in the implanted ear relative to the contralateral control ear 3 months following cochlear implantation. From the results of LDV measurements, it can be said that cochlear implantation has no significant delayed effect on the middle ear conductive mechanism. 4. Laryngoscope, 128:1207-1212, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Amplification options in unilateral aural atresia: an active middle ear implant or a bone conduction device?

PubMed

Agterberg, Martijn J H; Frenzel, Henning; Wollenberg, Barbara; Somers, Thomas; Cremers, Cor W R J; Snik, Ad F M

2014-01-01

There is no consensus on treatment of patients with congenital unilateral aural atresia. Currently, 3 intervention options are available, namely, surgical reconstruction, application of a bone-conduction device (BCD), or application of a middle ear implant. The present study aims to compare the BCD with the application of a middle ear implant. We hypothesized that cross-hearing (stimulating the cochlea by means of bone conduction contralateral to the implanted side) would cause BCD users to have difficulty performing localization tasks. Audiologic data of 4 adult patients with a middle ear implant coupled directly to the cochlea were compared with data of 4 adult patients fitted with an osseointegrated BCD. All patients were fitted during adulthood. The emphasis of this study is on directional hearing. The middle ear implant and the BCD improved sound localization of patients with congenital unilateral aural atresia. Unaided scores demonstrate a large variation. Our results demonstrate that there was no advantage of the middle ear implant over the BCD for directional hearing in patients who had no amplification in childhood. The BCD users had the best bandwidth.

Binaural electric-acoustic interactions recorded from the inferior colliculus of Guinea pigs: the effect of masking observed in the central nucleus of the inferior colliculus.

PubMed

Noh, Heil; Lee, Dong-Hee

2012-09-01

To investigate the electric-acoustic interactions within the inferior colliculus of guinea pigs and to observe how central masking appears in invasive neural recordings of the inferior colliculus (IC). A platinum-iridium wire was inserted to scala tympani through cochleostomy with a depth no greater than 1 mm for intracochlear stimulation of electric pulse train. A 5 mm 100 µm, single-shank, thin-film, penetrating recording probe was inserted perpendicularly to the surface of the IC in the coronal plane at an angle of 30-40° off the parasagittal plane with a depth of 2.0-2.5 mm. The peripheral and central masking effects were compared using electric pulse trains to the left ear and acoustic noise to the left ear (ipsilateral) and to the right ear (contralateral). Binaural acoustic stimuli were presented with different time delays and compared with combined electric and acoustic stimuli. The averaged evoked potentials and total spike numbers were measured using thin-film electrodes inserted into the central nucleus of the IC. Ipsilateral noise had more obvious effects on the electric response than did contralateral noise. Contralateral noise decreased slightly the response amplitude to the electric pulse train stimuli. Immediately after the onset of acoustic noise, the response pattern changed transiently with shorter response intervals. The effects of contralateral noise were evident at the beginning of the continuous noise. The total spike number decreased when the binaural stimuli reached the IC most simultaneously. These results suggest that central masking is quite different from peripheral masking and occurs within the binaural auditory system, and this study showed that the effect of masking could be observed in the IC recording. These effects are more evident and consistent with the psychophysical data from spike number analyses than with the previously reported gross potential data.

The cochlear implant as a tinnitus treatment.

PubMed

Vallés-Varela, Héctor; Royo-López, Juan; Carmen-Sampériz, Luis; Sebastián-Cortés, José M; Alfonso-Collado, Ignacio

2013-01-01

Tinnitus is a symptom of high prevalence in patients with cochlear pathology. We studied the evolution of tinnitus in patients undergoing unilateral cochlear implantation for treatment of profound hearing loss. This was a longitudinal, retrospective study of patients that underwent unilateral cochlear implantation and who had bilateral tinnitus. Tinnitus was assessed quantitatively and qualitatively before surgery and at 6 and 12 months after surgery. We evaluated 20 patients that underwent unilateral cochlear implantation with a Nucleus(®) CI24RE Contour Advance™ electrode device. During the periods in which the device was in operation, improvement or disappearance of tinnitus was evidenced in the ipsilateral ear in 65% of patients, and in the contralateral ear, in 50%. In periods in which the device was disconnected, improvement or disappearance of tinnitus was found in the ipsilateral ear in 50% of patients, and in the ear contralateral to the implant in 45% of the patients. In 10% of the patients, a new tinnitus appeared in the ipsilateral ear. The patients with profound hearing loss and bilateral tinnitus treated with unilateral cochlear implantation improved in a high percentage of cases, in the ipsilateral ear and in the contralateral ear. Copyright © 2012 Elsevier España, S.L. All rights reserved.

[The Heidelberg CI database module : Quality control in hearing restoration with cochlear implants].

PubMed

Herisanu, I T; Hoth, S; Praetorius, M

2016-12-01

Cochlear implants (CI) have been established as the therapy of choice for functional deafness. The number of CI-rehabilitated patients is continuously growing. The resulting data can provide important information for physicians, health insurance companies, and scientists. Assessment and structuring of data becomes more feasible with the application of modern database systems. In collaboration with Innoforce Est., Liechtenstein, the authors developed a database module for the specific needs of CI patients. Data of 100 patients were included and evaluated. The main features of the module and an example data analysis are presented. Analysis of data from these 100 patients reveals 50 men and 50 women aged between 1 and 87 years, with a maximum value in the 51-60-years age group. More than 50% of the patients were also severely hearing impaired in the contralateral ear and fitted the CI indication criteria. Functional deafness in the ear subsequently fitted with CI in most of the patients had arisen more than 20 years previously. Preoperative diagnostic electrical stimulation of the cochlear nerve was positive in 67 patients. All 100 patients perceived auditory sensations with the CI. The presented patient cohort is representative of patients at the Department of Otorhinolaryngology, University of Heidelberg Medical Center, Germany, and the demographic distribution is in accordance with the literature. The state of the contralateral ear, often also fitting the CI indication, is not surprising, as cochlear implantation is a comparatively new procedure. Preoperative electrical stimulation turned out not to be significant by itself. The hearing results and overview of complications were easy to calculate in comparison to a pure data storage system such as i.s.h.med.

Contralateral Occlusion Test: The effect of external ear canal occlusion on hearing thresholds.

PubMed

Reis, Luis Roque; Fernandes, Paulo; Escada, Pedro

Bedside testing with tuning forks may decrease turnaround time and improve decision making for a quick qualitative assessment of hearing loss. The purpose of this study was to quantify the effects of ear canal occlusion on hearing, in order to decide which tuning fork frequency is more appropriate to use for quantifying hearing loss with the Contralateral Occlusion Test. Twenty normal-hearing adults (forty ears) underwent sound field pure tone audiometry with and without ear canal occlusion. Each ear was tested with the standard frequencies. The contralateral ear was suppressed with by masking. Ear occlusion was performed by two examiners. Participants aged between 21 and 30 years (25.6±3.03 years) showed an increase in hearing thresholds with increasing frequencies from 19.94dB (250Hz) to 39.25dB (2000Hz). The threshold difference between occluded and unoccluded conditions was statistically significant and increased from 10.69dB (250Hz) to 32.12dB (2000Hz). There were no statistically significant differences according to gender or between the examiners. The occlusion effect increased the hearing thresholds and became more evident with higher frequencies. The occlusion method as performed demonstrated reproducibility. In the Contralateral Occlusion Test, 256Hz or 512Hz tuning forks should be used for diagnosis of mild hearing loss, and a 2048Hz tuning fork should be used for moderate hearing loss. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Amplification in the rehabilitation of unilateral deafness: speech in noise and directional hearing effects with bone-anchored hearing and contralateral routing of signal amplification.

PubMed

Lin, Li-Mei; Bowditch, Stephen; Anderson, Michael J; May, Bradford; Cox, Kenneth M; Niparko, John K

2006-02-01

Vibromechanical stimulation with a semi-implantable bone conductor (Entific BAHA device) overcomes some of the head-shadow effects in unilateral deafness. What specific rehabilitative benefits are observed when the functional ear exhibits normal hearing versus moderate sensorineural hearing loss (SNHL)? The authors conducted a prospective trial of subjects with unilateral deafness in a tertiary care center. This study comprised adults with unilateral deafness (pure-tone average [PTA] > 90 dB; Sp.D. < 20%) and either normal monaural hearing (n = 18) or moderate SNHL (PTA = 25-50 dB: Sp.D. > 75%) in the contralateral functional ear (n = 5). Subjects were fit with contralateral routing of signal (CROS) devices for 1 month and tested before (mastoid) implantation, fitting, and testing with a bone-anchored hearing aid (BAHA). Outcome measures were: 1) subjective benefit; 2) source localization tests (Source Azimuth Identification in Noise Test [SAINT]); 3) speech discrimination in quiet and in noise assessed with Hearing In Noise Test (HINT) protocols. There was consistent satisfaction with BAHA amplification and poor acceptance of CROS amplification. General directional hearing decreased with CROS use and was unchanged by BAHA and directional microphone aids. Relative to baseline and CROS, BAHA produced significantly better speech recognition in noise. Twenty-two of 23 subjects followed up in this study continue to use their BAHA device over an average follow-up period of 30.24 months (range, 51-12 months). BAHA amplification on the side of a deaf ear yields greater benefit in subjects with monaural hearing than does CROS amplification. Advantages likely related to averting the interference of speech signals delivered to the better ear, as occurs with conventional CROS amplification, while alleviating the negative head-shadow effects of unilateral deafness. The advantages of head-shadow reduction in enhancing speech recognition with noise in the hearing ear outweigh disadvantages inherent in head-shadow reduction that can occur by introducing noise from the deaf side. The level of hearing impairment correlates with incremental benefit provided by the BAHA. Patients with a moderate SNHL in the functioning ear perceived greater increments in benefit, especially in background noise, and demonstrated greater improvements in speech understanding with BAHA amplification.

Comparison of the benefits of cochlear implantation versus contra-lateral routing of signal hearing aids in adult patients with single-sided deafness: study protocol for a prospective within-subject longitudinal trial.

PubMed

Kitterick, Pádraig T; O'Donoghue, Gerard M; Edmondson-Jones, Mark; Marshall, Andrew; Jeffs, Ellen; Craddock, Louise; Riley, Alison; Green, Kevin; O'Driscoll, Martin; Jiang, Dan; Nunn, Terry; Saeed, Shakeel; Aleksy, Wanda; Seeber, Bernhard U

2014-01-01

Individuals with a unilateral severe-to-profound hearing loss, or single-sided deafness, report difficulty with listening in many everyday situations despite having access to well-preserved acoustic hearing in one ear. The standard of care for single-sided deafness available on the UK National Health Service is a contra-lateral routing of signals hearing aid which transfers sounds from the impaired ear to the non-impaired ear. This hearing aid has been found to improve speech understanding in noise when the signal-to-noise ratio is more favourable at the impaired ear than the non-impaired ear. However, the indiscriminate routing of signals to a single ear can have detrimental effects when interfering sounds are located on the side of the impaired ear. Recent published evidence has suggested that cochlear implantation in individuals with a single-sided deafness can restore access to the binaural cues which underpin the ability to localise sounds and segregate speech from other interfering sounds. The current trial was designed to assess the efficacy of cochlear implantation compared to a contra-lateral routing of signals hearing aid in restoring binaural hearing in adults with acquired single-sided deafness. Patients are assessed at baseline and after receiving a contra-lateral routing of signals hearing aid. A cochlear implant is then provided to those patients who do not receive sufficient benefit from the hearing aid. This within-subject longitudinal design reflects the expected care pathway should cochlear implantation be provided for single-sided deafness on the UK National Health Service. The primary endpoints are measures of binaural hearing at baseline, after provision of a contra-lateral routing of signals hearing aid, and after cochlear implantation. Binaural hearing is assessed in terms of the accuracy with which sounds are localised and speech is perceived in background noise. The trial is also designed to measure the impact of the interventions on hearing- and health-related quality of life. This multi-centre trial was designed to provide evidence for the efficacy of cochlear implantation compared to the contra-lateral routing of signals. A purpose-built sound presentation system and established measurement techniques will provide reliable and precise measures of binaural hearing. Current Controlled Trials http://www.controlled-trials.com/ISRCTN33301739 (05/JUL/2013).

Separating the contributions of olivocochlear and middle ear muscle reflexes in modulation of distortion product otoacoustic emission levels.

PubMed

Wolter, Nikolaus E; Harrison, Robert V; James, Adrian L

2014-01-01

Mediated by the medial olivocochlear system (MOCS), distortion product otoacoustic emission (DPOAE) levels are reduced by presentation of contralateral acoustic stimuli. Such acoustic signals can also evoke a middle ear muscle reflex (MEMR) that also attenuates recorded DPOAE levels. Our aim is to clearly differentiate these two inhibitory mechanisms and to analyze each separately, perhaps allowing the development of novel tests of hearing function. DPOAE were recorded in real time from chinchillas with normal auditory brainstem response thresholds and middle ear function. Amplitude reduction and its onset latency caused by contralateral presentation of intermittent narrow-band noise (NBN) were measured. Stapedius and tensor tympani muscle tendons were divided without disturbing the ossicular chain, and DPOAE testing was repeated. Peak reduction of (2f1 - f2) DPOAE levels occurred when the center frequency of contralateral NBN approximated the primary tone f2, indicating an f2-frequency-specific response. For a 4.5-kHz centered NBN, DPOAE (f2 = 4.4 kHz) inhibition was 0.1 dB (p < 0.001). This response remained present after tendon division, consistent with an MOCS origin. Low-frequency NBN (center frequency: 0.5 kHz) reduced otoacoustic emission levels (0.1 dB, p < 0.001) across a wide range of DPOAE frequencies. This low-frequency response was abolished by division of the middle ear muscle tendons, clearly indicating MEMR involvement. Following middle ear muscle tendon division, DPOAE inhibition by contralateral stimuli approximating the primary tone f2 persists, whereas responses evoked by lower contralateral frequencies are abolished. This distinguishes the different roles of the MOCS (f2 frequency specific) and MEMR (low frequency only) in contralateral modulation of DPOAE. This analysis helps clarify the pathways involved in an objective test that might have clinical benefit in the testing of neonates.

Bimodal Programming: A Survey of Current Clinical Practice.

PubMed

Siburt, Hannah W; Holmes, Alice E

2015-06-01

The purpose of this study was to determine the current clinical practice in approaches to bimodal programming in the United States. To be specific, if clinicians are recommending bimodal stimulation, who programs the hearing aid in the bimodal condition, and what method is used for programming the hearing aid? An 11-question online survey was created and sent via email to a comprehensive list of cochlear implant programming centers in the United States. The survey was sent to 360 recipients. Respondents in this study represented a diverse group of clinical settings (response rate: 26%). Results indicate little agreement about who programs the hearing aids, when they are programmed, and how they are programmed in the bimodal condition. Analysis of small versus large implant centers indicated small centers are less likely to add a device to the contralateral ear. Although a growing number of cochlear implant recipients choose to wear a hearing aid on the contralateral ear, there is inconsistency in the current clinical approach to bimodal programming. These survey results provide evidence of large variability in the current bimodal programming practices and indicate a need for more structured clinical recommendations and programming approaches.

The Hyperactivity of Efferent Auditory System in Patients with Schizophrenia: A Transient Evoked Otoacoustic Emissions Study

PubMed Central

Wahab, Suzaily; Abdul Rahman, Abdul Hamid; Sidek, Dinsuhaimi; Zakaria, Mohd. Normani

2016-01-01

Objective Electrophysiological studies, which are mostly focused on afferent pathway, have proven that auditory processing deficits exist in patients with schizophrenia. Nevertheless, reports on the suppressive effect of efferent auditory pathway on cochlear outer hair cells among schizophrenia patients are limited. The present, case-control, study examined the contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in patients with schizophrenia. Methods Participants were twenty-three healthy controls and sixteen schizophrenia patients with normal hearing, middle ear and cochlear outer hair cells function. Absolute non-linear and linear TEOAEs were measured in both ears by delivering clicks stimuli at 80 dB SPL and 60 dB SPL respectively. Subsequently, contralateral suppression was determined by subtracting the absolute TEOAEs response obtained at 60 dBpe SPL during the absence and presence of contralateral white noise delivered at 65 dB HL. No attention tasks were conducted during measurements. Results We found no significant difference in absolute TEOAEs responses at 80 dB SPL, in either diagnosis or ear groups (p>0.05). However, the overall contralateral suppression was significantly larger in schizophrenia patients (p<0.05). Specifically, patients with schizophrenia demonstrated significantly increased right ear contralateral suppression compared to healthy control (p<0.05). Conclusion The present findings suggest increased inhibitory effect of efferent auditory pathway especially on the right cochlear outer hair cells. Further studies to investigate increased suppressive effects are crucial to expand the current understanding of auditory hallucination mechanisms in schizophrenia patients. PMID:26766950

Gadolinium-enhanced inner ear magnetic resonance imaging for evaluation of delayed endolymphatic hydrops, including a bilateral case.

PubMed

Fukushima, Munehisa; Oya, Ryohei; Akazawa, Hitoshi; Tsuruta, Yukinori; Inohara, Hidenori

2016-01-01

The data suggests that gadolinium-enhanced inner ear MR imaging is useful for diagnosis of delayed endolymphatic hydrops (DEH) because it is independent of inner ear function, and the size of the affected endolymphatic space is clearly enlarged. This study was performed to semi-quantitatively evaluate the endolymphatic space in patients with all types of DEH using gadolinium-enhanced inner ear magnetic resonance (MR) imaging. Seven patients (age range = 21-77 years; five female, two male) with ipsilateral DEH (n = 5), contralateral DEH (n = 1), and bilateral DEH (n = 1). All patients underwent 3T MR imaging 4 h after intravenous injection of gadolinium. Software was used to determine the size of the endolymphatic space. Pure tone audiometry and caloric testing using an electronystagmogram were carried out. One side of the endolymphatic space was dominantly extended in patients with ipsilateral DEH, and both sides of the space were extended in patients with contralateral and bilateral DEH. In patients with ipsilateral DEH, the volume ratio of endolymph to vestibule was 2.5-4.3-times that in the unaffected ear. The volume ratio of endolymph to vestibule was nearly equal in patients with contralateral and bilateral DEH.

Influence of contralateral acoustic hearing on adult bimodal outcomes after cochlear implantation.

PubMed

Plant, Kerrie; van Hoesel, Richard; McDermott, Hugh; Dawson, Pamela; Cowan, Robert

2016-08-01

To examine post-implantation benefit and time taken to acclimate to the cochlear implant for adult candidates with more hearing in the contralateral non-implanted ear than has been previously considered within local candidacy guidelines. Prospective, within-subject experimental design. Forty postlingual hearing-impaired adult subjects with a contralateral ear word score in quiet ranging from 27% to 100% (median 67%). Post-implantation improvement of 2.4 dB and 4.0 dB was observed on a sentence in coincident babble test at presentation levels of 65 and 55 dB SPL respectively, and a 2.1 dB benefit in spatial release from masking (SRM) advantage observed when the noise location favoured the implanted side. Significant post-operative group mean change of between 2.1 and 3.0 was observed on the sub-scales of the speech, spatial, and qualities (SSQ) questionnaire. Degree of post-implantation speech reception threshold (SRT) benefit on the coincident babble test and on perception of soft speech and sounds in the environment was greater for subjects with less contralateral hearing. The degree of contralateral acoustic hearing did not affect time taken to acclimate to the device. The findings from this study support cochlear implantation for candidates with substantial acoustic hearing in the contralateral ear, and provide guidance regarding post-implantation expectations.

Central masking with bilateral cochlear implants

PubMed Central

Lin, Payton; Lu, Thomas; Zeng, Fan-Gang

2013-01-01

Across bilateral cochlear implants, contralateral threshold shift has been investigated as a function of electrode difference between the masking and probe electrodes. For contralateral electric masking, maximum threshold elevations occurred when the position of the masker and probe electrode was approximately place-matched across ears. The amount of masking diminished with increasing masker-probe electrode separation. Place-dependent masking occurred in both sequentially implanted ears, and was not affected by the masker intensity or the time delay from the masker onset. When compared to previous contralateral masking results in normal hearing, the similarities between place-dependent central masking patterns suggest comparable mechanisms of overlapping excitation in the central auditory nervous system. PMID:23363113

The MOC reflex during active listening to speech.

PubMed

Garinis, Angela C; Glattke, Theodore; Cone, Barbara K

2011-10-01

The purpose of this study was to test the hypothesis that active listening to speech would increase medial olivocochlear (MOC) efferent activity for the right vs. the left ear. Click-evoked otoacoustic emissions (CEOAEs) were evoked by 60-dB p.e. SPL clicks in 13 normally hearing adults in 4 test conditions for each ear: (a) in quiet; (b) with 60-dB SPL contralateral broadband noise; (c) with words embedded (at -3-dB signal-to-noise ratio [SNR]) in 60-dB SPL contralateral noise during which listeners directed attention to the words; and (d) for the same SNR as in the 3rd condition, with words played backwards. There was greater suppression during active listening compared with passive listening that was apparent in the latency range of 6- to 18-ms poststimulus onset. Ear differences in CEOAE amplitude were observed in all conditions, with right-ear amplitudes larger than those for the left. The absolute difference between CEOAE amplitude in quiet and with contralateral noise, a metric of suppression, was equivalent for right and left ears. When the amplitude differences were normalized, suppression was greater for noise presented to the right and the effect measured for a probe in the left ear. The findings support the theory that cortical mechanisms involved in listening to speech affect cochlear function through the MOC efferent system.

Comparison of the benefits of cochlear implantation versus contra-lateral routing of signal hearing aids in adult patients with single-sided deafness: study protocol for a prospective within-subject longitudinal trial

PubMed Central

2014-01-01

Background Individuals with a unilateral severe-to-profound hearing loss, or single-sided deafness, report difficulty with listening in many everyday situations despite having access to well-preserved acoustic hearing in one ear. The standard of care for single-sided deafness available on the UK National Health Service is a contra-lateral routing of signals hearing aid which transfers sounds from the impaired ear to the non-impaired ear. This hearing aid has been found to improve speech understanding in noise when the signal-to-noise ratio is more favourable at the impaired ear than the non-impaired ear. However, the indiscriminate routing of signals to a single ear can have detrimental effects when interfering sounds are located on the side of the impaired ear. Recent published evidence has suggested that cochlear implantation in individuals with a single-sided deafness can restore access to the binaural cues which underpin the ability to localise sounds and segregate speech from other interfering sounds. Methods/Design The current trial was designed to assess the efficacy of cochlear implantation compared to a contra-lateral routing of signals hearing aid in restoring binaural hearing in adults with acquired single-sided deafness. Patients are assessed at baseline and after receiving a contra-lateral routing of signals hearing aid. A cochlear implant is then provided to those patients who do not receive sufficient benefit from the hearing aid. This within-subject longitudinal design reflects the expected care pathway should cochlear implantation be provided for single-sided deafness on the UK National Health Service. The primary endpoints are measures of binaural hearing at baseline, after provision of a contra-lateral routing of signals hearing aid, and after cochlear implantation. Binaural hearing is assessed in terms of the accuracy with which sounds are localised and speech is perceived in background noise. The trial is also designed to measure the impact of the interventions on hearing- and health-related quality of life. Discussion This multi-centre trial was designed to provide evidence for the efficacy of cochlear implantation compared to the contra-lateral routing of signals. A purpose-built sound presentation system and established measurement techniques will provide reliable and precise measures of binaural hearing. Trial registration Current Controlled Trials http://www.controlled-trials.com/ISRCTN33301739 (05/JUL/2013) PMID:25152694

Vestibular evoked myogenic potentials in response to lateral skull taps are dependent on two different mechanisms.

PubMed

Brantberg, Krister; Westin, Magnus; Löfqvist, Lennart; Verrecchia, Luca; Tribukait, Arne

2009-05-01

To explore the mechanisms for skull tap induced vestibular evoked myogenic potentials (VEMP). The muscular responses were recorded over both sternocleidomastoid (SCM) muscles using skin electrodes. A skull tapper which provided a constant stimulus intensity was used to test cervical vestibular evoked myogenic potentials (VEMP) in response to lateral skull taps in healthy subjects (n=10) and in patients with severe unilateral loss of vestibular function (n=10). Skull taps applied approximately 2 cm above the outer ear canal caused highly reproducible VEMP. There were differences in VEMP in both normals and patients depending on side of tapping. In normals, there was a positive-negative ("normal") VEMP on the side contra-lateral to the skull tapping, but no significant VEMP ipsi-laterally. In patients, skull taps above the lesioned ear caused a contra-lateral positive-negative VEMP (as it did in the normals), in addition there was an ipsi-lateral negative-positive ("inverted") VEMP. When skull taps were presented above the healthy ear there was only a small contra-lateral positive-negative VEMP but, similar to the normals, no VEMP ipsi-laterally. The present data, in conjunction with earlier findings, support a theory that skull-tap VEMP responses are mediated by two different mechanisms. It is suggested that skull tapping causes both a purely ipsi-lateral stimulus side independent SCM response and a bilateral and of opposite polarity SCM response that is stimulus side dependent. Possibly, the skull tap induced VEMP responses are the sum of a stimulation of two species of vestibular receptors, one excited by vibration (which is rather stimulus site independent) and one excited by translation (which is more stimulus site dependent). Skull-tap VEMP probably have two different mechanisms. Separation of the two components might reveal the status of different labyrinthine functions.

Semiautomated Middle Ear Volume Measurement as a Predictor of Postsurgical Outcomes for Congenital Aural Atresia.

PubMed

Kabadi, S J; Ruhl, D S; Mukherjee, S; Kesser, B W

2018-02-01

Middle ear space is one of the most important components of the Jahrsdoerfer grading system (J-score), which is used to determine surgical candidacy for congenital aural atresia. The purpose of this study was to introduce a semiautomated method for measuring middle ear volume and determine whether middle ear volume, either alone or in combination with the J-score, can be used to predict early postoperative audiometric outcomes. A retrospective analysis was conducted of 18 patients who underwent an operation for unilateral congenital aural atresia at our institution. Using the Livewire Segmentation tool in the Carestream Vue PACS, we segmented middle ear volumes using a semiautomated method for all atretic and contralateral normal ears on preoperative high-resolution CT imaging. Postsurgical audiometric outcome data were then analyzed in the context of these middle ear volumes. Atretic middle ear volumes were significantly smaller than those in contralateral normal ears ( P < .001). Patients with atretic middle ear volumes of >305 mm 3 had significantly better postoperative pure tone average and speech reception thresholds than those with atretic ears below this threshold volume ( P = .01 and P = .006, respectively). Atretic middle ear volume incorporated into the J-score offered the best association with normal postoperative hearing (speech reception threshold ≤ 30 dB; OR = 37.8, P = .01). Middle ear volume, calculated in a semiautomated fashion, is predictive of postsurgical audiometric outcomes, both independently and in combination with the conventional J-score. © 2018 by American Journal of Neuroradiology.

Prospective study of inner ear radiation dose and hearing loss in head-and-neck cancer patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Charlie C.; Eisbruch, Avraham; Lee, Julia S.

Purpose: To determine the relationship between the radiation dose to the inner ear and long-term hearing loss. Methods and Materials: Eligible patients included those receiving curative radiotherapy (RT) for head-and-neck cancer. After enrollment, patients underwent three-dimensional conformal RT planning and delivery (180-200 cGy/fraction) appropriate for their disease site and stage. The inner ear was contoured on axial CT planning images. Dose-volume histograms, as well as the mean and maximal dose for each structure, were calculated. Patients underwent pure tone audiometry at baseline (before treatment) and 1, 6, 12, 24, and 36 months after RT. The threshold level (the greater themore » value, the more hearing loss) in decibels was recorded for 250, 500, 1000, 2000, 4000, and 8000 Hz. For patients receiving predominantly unilateral RT, the contralateral ear served as the de facto control. The differences in threshold level between the ipsilateral and contralateral ears were calculated, and the temporal pattern and dose-response relation of hearing loss were analyzed using statistical methods that take into account the correlation between two ears in the same subject and repeated, sequential measurements of each subject. Results: Of the 40 patients enrolled in this study, 35 qualified for analysis. Four patients who received concurrent chemotherapy and RT were analyzed separately. The 31 unilaterally treated patients received a median dose of 47.4 Gy (range, 14.1-68.8 Gy) to the ipsilateral inner ear and 4.2 Gy (range, 0.5-31.3 Gy) to the contralateral inner ear. Hearing loss was associated with the radiation dose received by the inner ear (loss of 210dB was observed in ears receiving {>=}45 Gy) and was most appreciable in the higher frequencies ({>=}2000 Hz). For a 60-year-old patient with no previous hearing loss in either ear, after receiving 45 Gy, the ipsilateral ear, according to our clinical model, would have a 19.3-dB (95% confidence interval [CI], 15.5-23.0) and 5.4-dB (95% CI, 3.5-7.5) hearing decrement compared with the contralateral ear for 8000 Hz and 1000 Hz, respectively. Age and an initial hearing difference within an ear pair also affected hearing loss. The baseline hearing threshold was inversely related to radiation-induced hearing loss. The degree of hearing loss was dependent on the frequency tested, age, baseline hearing, and baseline difference in hearing between a patient's two ears. Conclusion: High-frequency ({>=}2000 Hz) hearing acuity worsens significantly after RT in a dose-dependent fashion. A larger number of patients needs to be studied to validate these results. This knowledge can be applied to create guidelines regarding future dose limits to the auditory apparatus for patients undergoing head-and-neck RT.« less

Comparison of packing material in an animal model of middle ear trauma.

PubMed

Perez, Enrique; Hachem, Ralph Abi; Carlton, Daniel; Bueno, Isabel; Vernon, Stephen; Van De Water, Thomas R; Angeli, Simon I

2016-01-01

To compare the performance of absorbable gelatin sponge (AGS) with polyurethane foam (PUF) as middle ear packing material after mucosal trauma. Using a randomized, controlled and blinded study design fifteen guinea pigs underwent middle ear surgery with mucosal trauma performed on both ears. One ear was packed with either PUF or AGS while the contralateral ear remained untreated and used as non-packed paired controls. Auditory brainstem response (ABR) thresholds were measured pre-operatively and repeated at 1, 2, and 6weeks postoperatively. Histological analysis of middle ear mucosa was done in each group to evaluate the inflammatory reaction and wound healing. Another eighteen animals underwent middle ear wounding and packing in one ear while the contralateral ear was left undisturbed as control. Twelve guinea pigs were euthanized at 2weeks postoperatively, and six were euthanized at 3days post-operatively. Mucosal samples were collected for analysis of TGF-β1 levels by enzyme-linked immunosorbent assay. ABR recordings demonstrate that threshold level changes from baseline were minor in PUF packed and control ears. Threshold levels were higher in the AGS packed ears compared with both control and PUF packed ears for low frequency stimuli. Histological analysis showed persistence of packing material at 6weeks postoperatively, inflammation, granulation tissue formation, foreign body reaction and neo-osteogenesis in both AGS and PUF groups. TGF-β1 protein levels did not differ between groups. PUF and AGS packing cause inflammation and neo-osteogenesis in the middle ear following wounding of the mucosa and packing. Copyright © 2016 Elsevier Inc. All rights reserved.

Right-ear precedence and vocal emotion contagion: The role of the left hemisphere.

PubMed

Schepman, Astrid; Rodway, Paul; Cornmell, Louise; Smith, Bethany; de Sa, Sabrina Lauren; Borwick, Ciara; Belfon-Thompson, Elisha

2018-05-01

Much evidence suggests that the processing of emotions is lateralized to the right hemisphere of the brain. However, under some circumstances the left hemisphere might play a role, particularly for positive emotions and emotional experiences. We explored whether emotion contagion was right-lateralized, lateralized valence-specifically, or potentially left-lateralized. In two experiments, right-handed female listeners rated to what extent emotionally intoned pseudo-sentences evoked target emotions in them. These sound stimuli had a 7 ms ear lead in the left or right channel, leading to stronger stimulation of the contralateral hemisphere. In both experiments, the results revealed that right ear lead stimuli received subtly but significantly higher evocation scores, suggesting a left hemisphere dominance for emotion contagion. A control experiment using an emotion identification task showed no effect of ear lead. The findings are discussed in relation to prior findings that have linked the processing of emotional prosody to left-hemisphere brain regions that regulate emotions, control orofacial musculature, are involved in affective empathy processing areas, or have an affinity for processing emotions socially. Future work is needed to eliminate alternative interpretations and understand the mechanisms involved. Our novel binaural asynchrony method may be useful in future work in auditory laterality.

Frequency specificity and left-ear advantage of medial olivocochlear efferent modulation: a study based on stimulus frequency otoacoustic emission.

PubMed

Xing, Dongjia; Gong, Qin

2017-09-06

The medial olivocochlear (MOC) bundle is an auditory nucleus that projects efferent nerve fibers to the outer hair cells (OHCs) for synaptic innervation. The aim of the present study was to investigate the possible existence of frequency and ear specificity in MOC efferent modulation, as well as how MOC activation influences cochlear tuning. Stimulus frequency otoacoustic emissions (SFOAEs) were used to study MOC efferent modulation. Therefore, the current experiment was designed to compare the degree of SFOAE suppression in the both ears of 20 individuals at 1, 2, 4, and 8 kHz. We also compared changes in Q10 values of SFOAE suppression tuning curves at 1, 2, and 4 kHz under contralateral acoustic stimulation (CAS) and no-CAS conditions. We observed a significant reduction in SFOAE magnitude in the CAS condition compared with the no-CAS condition at 1 and 2 kHz in the left ear. A significant difference in CAS suppression was also found between the left and right ears at 1 and 2 kHz, with larger CAS suppression in the left ear. CAS further produced a statistically significant increase in the Q10 value at 1 kHz and a significant reduction in Q10 values at 2 and 4 kHz. These findings suggest a left-ear advantage in terms of CAS-induced MOC efferent SFOAE suppression, with larger MOC efferent modulation for lower frequencies, and cochlear tuning was sharpened by means of MOC activation at lower frequencies and broadened at higher frequencies.

Benefit of Wearing a Hearing Aid on the Unimplanted Ear in Adult Users of a Cochlear Implant

ERIC Educational Resources Information Center

Dunn, Camille C.; Tyler, Richard S.; Witt, Shelley A.

2005-01-01

The purpose of this investigation was to document performance of participants wearing a cochlear implant and hearing aid in opposite ears on speech-perception and localization tests. Twelve individuals who wore a cochlear implant and a hearing aid on contralateral ears were tested on their abilities to understand words in quiet and sentences in…

Two flaps and Z-plasty technique for correction of longitudinal ear lobe cleft.

PubMed

Lee, Paik-Kwon; Ju, Hong-Sil; Rhie, Jong-Won; Ahn, Sang-Tae

2005-06-01

Various surgical techniques have been reported for the correction of congenital ear lobe deformities. Our method, the two-flaps-and-Z-plasty technique, for correcting the longitudinal ear lobe cleft is presented. This technique is simple and easy to perform. It enables us to keep the bulkiness of the ear lobe with minimal tissue sacrifice, and to make a shorter operation scar. The small Z-plasty at the free ear lobe margin avoids notching deformity and makes the shape of the ear lobe smoother. The result is satisfactory in terms of matching the contralateral normal ear lobe in shape and symmetry.

Patient-reported speech in noise difficulties and hyperacusis symptoms and correlation with test results.

PubMed

Spyridakou, Chrysa; Luxon, Linda M; Bamiou, Doris E

2012-07-01

To compare self-reported symptoms of difficulty hearing speech in noise and hyperacusis in adults with auditory processing disorders (APDs) and normal controls; and to compare self-reported symptoms to objective test results (speech in babble test, transient evoked otoacoustic emission [TEOAE] suppression test using contralateral noise). A prospective case-control pilot study. Twenty-two participants were recruited in the study: 10 patients with reported hearing difficulty, normal audiometry, and a clinical diagnosis of APD; and 12 normal age-matched controls with no reported hearing difficulty. All participants completed the validated Amsterdam Inventory for Auditory Disability questionnaire, a hyperacusis questionnaire, a speech in babble test, and a TEOAE suppression test using contralateral noise. Patients had significantly worse scores than controls in all domains of the Amsterdam Inventory questionnaire (with the exception of sound detection) and the hyperacusis questionnaire (P < .005). Patients also had worse TEOAE suppression test results in both ears than controls; however, this result was not significant after Bonferroni correction. Strong correlations were observed between self-reported symptoms of difficulty hearing speech in noise and speech in babble test results in the right ear (ρ = 0.624, P = .002), and between self-reported symptoms of hyperacusis and TEOAE suppression test results in the right ear (ρ = -0.597 P = .003). There was no significant correlation between the two tests. A strong correlation was observed between right ear speech in babble and patient-reported intelligibility of speech in noise, and right ear TEOAE suppression by contralateral noise and hyperacusis questionnaire. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

Contribution of a contralateral hearing aid to perception of consonant voicing, intonation, and emotional state in adult cochlear implantees.

PubMed

Most, Tova; Gaon-Sivan, Gal; Shpak, Talma; Luntz, Michal

2012-01-01

Binaural hearing in cochlear implant (CI) users can be achieved either by bilateral implantation or bimodally with a contralateral hearing aid (HA). Binaural-bimodal hearing has the advantage of complementing the high-frequency electric information from the CI by low-frequency acoustic information from the HA. We examined the contribution of a contralateral HA in 25 adult implantees to their perception of fundamental frequency-cued speech characteristics (initial consonant voicing, intonation, and emotions). Testing with CI alone, HA alone, and bimodal hearing showed that all three characteristics were best perceived under the bimodal condition. Significant differences were recorded between bimodal and HA conditions in the initial voicing test, between bimodal and CI conditions in the intonation test, and between both bimodal and CI conditions and between bimodal and HA conditions in the emotion-in-speech test. These findings confirmed that such binaural-bimodal hearing enhances perception of these speech characteristics and suggest that implantees with residual hearing in the contralateral ear may benefit from a HA in that ear.

Reconstruction of Moderately Constricted Ears by Combining V-Y Advancement of Helical Root, Conchal Cartilage Graft, and Mastoid Hitch.

PubMed

Elshahat, Ahmed; Lashin, Riham

2016-01-01

Despite the multitude of corrective procedures described in the literature, adequate surgical correction of the congenital constricted ear remains a challenge. The maintenance of the shape and size of the reconstructed upper neohelix poses a particular problem. In the present study, a total of 12 cases of reconstruction were undertaken. All of them were moderate (type IIA Tanzer classification) deformities. A combined procedure was adopted using a V-Y advancement of the helical root, cartilage scoring, and cartilage grafting from the contralateral concha to reconstruct the upper helix. A mastoid hitch was used as an adjunct to these procedures to maintain helical elevation and prevent recurrence. Mean follow-up period was 6 months. RESULTS were excellent (n = 7), good (n = 4), and fair (n = 1). Paired t test showed a significant increase in the height of the constricted ear postoperatively (P < .001) and a nonsignificant difference between the height of the constricted and contralateral ears postoperatively (P > .05). Apart from dislodgment of the mastoid hitch suture in 1 patient, no complications were recorded. This combined technique is useful in correcting moderately constricted ear deformities.

Imaging the Spatio-Temporal Dynamics of Supragranular Activity in the Rat Somatosensory Cortex in Response to Stimulation of the Paws

PubMed Central

Morales-Botello, M. L.; Aguilar, J.; Foffani, G.

2012-01-01

We employed voltage-sensitive dye (VSD) imaging to investigate the spatio-temporal dynamics of the responses of the supragranular somatosensory cortex to stimulation of the four paws in urethane-anesthetized rats. We obtained the following main results. (1) Stimulation of the contralateral forepaw evoked VSD responses with greater amplitude and smaller latency than stimulation of the contralateral hindpaw, and ipsilateral VSD responses had a lower amplitude and greater latency than contralateral responses. (2) While the contralateral stimulation initially activated only one focus, the ipsilateral stimulation initially activated two foci: one focus was typically medial to the focus activated by contralateral stimulation and was stereotaxically localized in the motor cortex; the other focus was typically posterior to the focus activated by contralateral stimulation and was stereotaxically localized in the somatosensory cortex. (3) Forepaw and hindpaw somatosensory stimuli activated large areas of the sensorimotor cortex, well beyond the forepaw and hindpaw somatosensory areas of classical somatotopic maps, and forepaw stimuli activated larger cortical areas with greater activation velocity than hindpaw stimuli. (4) Stimulation of the forepaw and hindpaw evoked different cortical activation dynamics: forepaw responses displayed a clear medial directionality, whereas hindpaw responses were much more uniform in all directions. In conclusion, this work offers a complete spatio-temporal map of the supragranular VSD cortical activation in response to stimulation of the paws, showing important somatotopic differences between contralateral and ipsilateral maps as well as differences in the spatio-temporal activation dynamics in response to forepaw and hindpaw stimuli. PMID:22829873

Parabrachial nucleus neuronal responses to off-vertical axis rotation in macaques

PubMed Central

McCandless, Cyrus H.; Balaban, Carey D.

2010-01-01

The caudal aspect of the parabrachial nucleus (PBN) contains neurons responsive to whole body, periodic rotational stimulation in alert monkeys. This study characterizes the angular and linear motion-sensitive response properties of PBN unit responses during off-vertical axis rotation (OVAR) and position trapezoid stimulation. The OVAR responses displayed a constant firing component which varied from the firing rate at rest. Nearly two-thirds of the units also modulated their discharges with respect to head orientation (re: gravity) during constant velocity OVAR stimulation. The modulated response magnitudes were equal during ipsilateral and contralateral OVARs, indicative of a one-dimensional accelerometer. These response orientations during OVAR divided the units into three spatially tuned populations, with peak modulation responses centered in the ipsilateral ear down, contralateral anterior semicircular canal down, and occiput down orientations. Because the orientation of the OVAR modulation response was opposite in polarity to the orientation of the static tilt component of responses to position trapezoids for the majority of units, the linear acceleration responses were divided into colinear dynamic linear and static tilt components. The orientations of these unit responses formed two distinct population response axes: (1) units with an interaural linear response axis and (2) units with an ipsilateral anterior semicircular canal-contralateral posterior semicircular canal plane linear response axis. The angular rotation sensitivity of these units is in a head-vertical plane that either contains the linear acceleration response axis or is perpendicular to the linear acceleration axis. Hence, these units behave like head-based (‘strap-down’) inertial guidance sensors. Because the PBN contributes to sensory and interoceptive processing, it is suggested that vestibulo-recipient caudal PBN units may detect potentially dangerous anomalies in control of postural stability during locomotion. In particular, these signals may contribute to the range of affective and emotional responses that include panic associated with falling, malaise associated with motion sickness and mal-de-debarquement, and comorbid balance and anxiety disorders. PMID:20039027

Analysis of Eustachian Tube Dysfunction by Dynamic Slow Motion Video Endoscopy and Eustachian Tube Dysfunction Questionnaire in Chronic Otitis Media

PubMed Central

Han, Won Gue; Yoo, Jun; Rah, Yoon Chan; Chang, Jiwon; Im, Gi Jung; Song, Jae-Jun; Chae, Sung Won; Jung, Hak Hyun; Choi, June

2017-01-01

Objectives Eustachian tube dysfunction has been associated with most cases of middle-ear disease. We aimed to assess the effectiveness of dynamic slow motion video endoscopy (DSVE) as a test of eustachian tube dysfunction. Furthermore, we assessed the correlation of the test with the Valsalva maneuver, the seven-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7), and intraoperative findings of the eustachian tube. Methods We retrospectively reviewed medical records from April to September 2014 to identify patients who were diagnosed with chronic otitis media (COM) at Korea University Ansan Hospital. They all underwent surgery because of COM without cholesteatoma and were assessed via the DSVE and ETDQ-7 to determine eustachian tube function. Results We reviewed 46 COM patients and examined 46 ears with COM and 46 ears on the contralateral side to COM that were thought to be normal. The mean DSVE grade in COM ears was 1.57±0.96, while the mean DSVE grade in contralateral ears was 1.15±0.94. The difference in DSVE between COM ears and normal ears was statistically significant (P=0.006). In the ETDQ-7, a higher score was related to intraoperative obstruction of the eustachian tube (P=0.012). Conclusion DSVE and ETDQ-7 can provide information regarding preoperative status of eustachian tube dysfunction by measuring dynamic structural changes of the eustachian tube in combination with other diagnostic tests. PMID:28602066

Musicianship enhances ipsilateral and contralateral efferent gain control to the cochlea.

PubMed

Bidelman, Gavin M; Schneider, Amy D; Heitzmann, Victoria R; Bhagat, Shaum P

2017-02-01

Human hearing sensitivity is easily compromised with overexposure to excessively loud sounds, leading to permanent hearing damage. Consequently, finding activities and/or experiential factors that distinguish "tender" from "tough" ears (i.e., acoustic vulnerability) would be important for identifying people at higher risk for hearing damage. To regulate sound transmission and protect the inner ear against acoustic trauma, the auditory system modulates gain control to the cochlea via biological feedback of the medial olivocochlear (MOC) efferents, a neuronal pathway linking the lower brainstem and cochlear outer hair cells. We hypothesized that a salient form of auditory experience shown to have pervasive neuroplastic benefits, namely musical training, might act to fortify hearing through tonic engagement of these reflexive pathways. By measuring MOC efferent feedback via otoacoustic emissions (cochlear emitted sounds), we show that dynamic ipsilateral and contralateral cochlear gain control is enhanced in musically-trained individuals. Across all participants, MOC strength was correlated with the years of listeners' training suggested that efferent gain control is experience dependent. Our data provide new evidence that intensive listening experience(s) (e.g., musicianship) can strengthen the ipsi/contralateral MOC efferent system and sound regulation to the inner ear. Implications for reducing acoustic vulnerability to damaging sounds are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of Removing Low-Frequency Electric Information on Speech Perception with Bimodal Hearing

ERIC Educational Resources Information Center

Fowler, Jennifer R.; Eggleston, Jessica L.; Reavis, Kelly M.; McMillan, Garnett P.; Reiss, Lina A. J.

2016-01-01

Purpose: The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic-electric overlap. Method: Subjects were adult CI subjects with at…

Single-unit labeling of medial olivocochlear neurons: the cochlear frequency map for efferent axons.

PubMed

Brown, M Christian

2014-06-01

Medial olivocochlear (MOC) neurons are efferent neurons that project axons from the brain to the cochlea. Their action on outer hair cells reduces the gain of the "cochlear amplifier," which shifts the dynamic range of hearing and reduces the effects of noise masking. The MOC effects in one ear can be elicited by sound in that ipsilateral ear or by sound in the contralateral ear. To study how MOC neurons project onto the cochlea to mediate these effects, single-unit labeling in guinea pigs was used to study the mapping of MOC neurons for neurons responsive to ipsilateral sound vs. those responsive to contralateral sound. MOC neurons were sharply tuned to sound frequency with a well-defined characteristic frequency (CF). However, their labeled termination spans in the organ of Corti ranged from narrow to broad, innervating between 14 and 69 outer hair cells per axon in a "patchy" pattern. For units responsive to ipsilateral sound, the midpoint of innervation was mapped according to CF in a relationship generally similar to, but with more variability than, that of auditory-nerve fibers. Thus, based on CF mappings, most of the MOC terminations miss outer hair cells involved in the cochlear amplifier for their CF, which are located more basally. Compared with ipsilaterally responsive neurons, contralaterally responsive neurons had an apical offset in termination and a larger span of innervation (an average of 10.41% cochlear distance), suggesting that when contralateral sound activates the MOC reflex, the actions are different than those for ipsilateral sound. Copyright © 2014 the American Physiological Society.

Single-unit labeling of medial olivocochlear neurons: the cochlear frequency map for efferent axons

PubMed Central

2014-01-01

Medial olivocochlear (MOC) neurons are efferent neurons that project axons from the brain to the cochlea. Their action on outer hair cells reduces the gain of the “cochlear amplifier,” which shifts the dynamic range of hearing and reduces the effects of noise masking. The MOC effects in one ear can be elicited by sound in that ipsilateral ear or by sound in the contralateral ear. To study how MOC neurons project onto the cochlea to mediate these effects, single-unit labeling in guinea pigs was used to study the mapping of MOC neurons for neurons responsive to ipsilateral sound vs. those responsive to contralateral sound. MOC neurons were sharply tuned to sound frequency with a well-defined characteristic frequency (CF). However, their labeled termination spans in the organ of Corti ranged from narrow to broad, innervating between 14 and 69 outer hair cells per axon in a “patchy” pattern. For units responsive to ipsilateral sound, the midpoint of innervation was mapped according to CF in a relationship generally similar to, but with more variability than, that of auditory-nerve fibers. Thus, based on CF mappings, most of the MOC terminations miss outer hair cells involved in the cochlear amplifier for their CF, which are located more basally. Compared with ipsilaterally responsive neurons, contralaterally responsive neurons had an apical offset in termination and a larger span of innervation (an average of 10.41% cochlear distance), suggesting that when contralateral sound activates the MOC reflex, the actions are different than those for ipsilateral sound. PMID:24598524

Contralateral suppression of transient otoacoustic emissions and sentence recognition in noise in young adults.

PubMed

Stuart, Andrew; Butler, Alyson K

2012-10-01

One purported role of the medial olivocochlear (MOC) efferent system is to reduce the effects of masking noise. MOC system functioning can be evaluated noninvasively in humans through contralateral suppression of otoacoustic emissions. It has been suggested that the strength of the MOC efferent activity should be positively associated with listening performance in noise. The objective of the study was to further explore this notion by examining contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) and sentence recognition in two noises with normal hearing young adults. A repeated measures multivariate quasi-experimental design was employed. Thirty-two normal hearing young adult females participated. Reception thresholds for sentences (RTSs) were determined monaurally and binaurally in quiet and in competing continuous and interrupted noises. Both noises had an identical power spectrum and differed only in their temporal continuity. "Release from masking" was computed by subtracting RTS signal-to-noise ratios in interrupted from continuous noise. TEOAEs were evoked with 80 dB peSPL click stimuli. To examine contralateral suppression, TEOAEs were evaluated with 60 dB peSPL click stimuli with and without a contralateral 65 dB SPL white noise suppressor. A binaural advantage was observed for RTSs in quiet and noise (p < .0001) while there was no difference between ears (p >.05). In noise, performance was superior in the interrupted noise (i.e., RTSs were lower vs. continuous noise; p < .0001). There were no statistically significant differences in TEOAE levels between ears (p >.05). There was also no significant difference in the amount of suppression between ears (p = .41). There were no significant correlations or predictive linear relations between the amount of TEOAE suppression and any indices of sentence recognition in noise (i.e., RTS signal-to-noise ratios and release from masking; p > .05). The findings are not consistent with the notion that increased medial olivocochlear efferent feedback, as assessed via contralateral suppression of TEOAEs, is associated with improved speech perception in continuous and interrupted noise. American Academy of Audiology.

Evidence-based guidelines for recommending cochlear implantation for postlingually deafened adults.

PubMed

Leigh, Jaime R; Moran, Michelle; Hollow, Rodney; Dowell, Richard C

2016-01-01

Adult selection criteria for cochlear implantation have been developed based on analysis of the post-operative performance of a large group of postlingually deafened adults. Original criteria published in 2004 were reviewed and amended to reflect outcomes currently being achieved by implant recipients. Retrospective review of 12-month post-operative speech perception performance of adults implanted at the Eye and Ear Hospital, Melbourne, Australia. A total of 382 postlingually deafened adults, using a Freedom, Nucleus 5, or CI422 Slim Straight cochlear implant were used to create a comparative set of data. Revised guidelines suggest that adults with postlingual hearing loss can now be considered cochlear implant candidates if they obtain scores of up to 55% for open-set phonemes in quiet in the ear to be implanted. Functional benefit may vary depending on the recipients' contralateral hearing. This study supports the provision of cochlear implants to candidates with significant residual hearing when at least one ear meets the criterion outlined above. Patient-specific counseling is required to ensure the potential to benefit predicted by the current model is acceptable to the individual patient and their family. Counseling regarding functional benefit must take into consideration hearing in the contralateral ear.

The application of direct current electrical stimulation of the ear and cervical spine kinesitherapy in tinnitus treatment.

PubMed

Mielczarek, Marzena; Konopka, Wieslaw; Olszewski, Jurek

2013-02-01

The aim of the study was to evaluate the effectiveness of electrical stimulations of the hearing organ in tinnitus treatment adapting the frequency of stimulation according to tinnitus frequency, to assess the influence of cervical spine kinesitherapy on tinnitus, as well as to evaluate hearing after electrical stimulations alone and together with cervical spine kinesitherapy. The study comprised 80 tinnitus, sensorineural hearing loss patients (119 tinnitus ears) divided into two groups. In group I (n - 58 tinnitus ears) electrical stimulation of the hearing organ was performed, in group II (n - 61 tinnitus ears) electrical stimulation together with cervical spine kinesitherapy. Hydrotransmissive, selective electrical stimulations were conducted using direct, rectangular current. The passive electrode was placed on the forehead, the active--a silver probe--was immersed in the external ear canal in 0.9% saline solution. The treatment involved fifteen applications of electrical stimulations (each lasted for 4 min) administered three or four times a week (whole treatment lasted approximately 30 days). The evaluation of the results considered a case history (change from permanent to temporary tinnitus), questionnaires (the increase/decrease of the total points) and the audiometric evaluation of hearing level. Before the treatment, group I comprised 51 ears (87.93%) with permanent, and 7 ears (12.07%) with temporary tinnitus; group II - 55 ears (90.17%) with permanent and 6 ears (9.83%) with temporary tinnitus. After the treatment, in both groups the number of ears with permanent tinnitus decreased considerably obtaining the pauses or disappearing of tinnitus. Directly after the treatment, group I comprised 25 ears (43.11%) with permanent, and 10 ears (17.24%) with temporary tinnitus, in 23 ears (39.65%) tinnitus disappeared; group II - 33 ears (54.1%) with permanent and 11 ears (18.03%) with temporary tinnitus, in 17 ears (27.87%) tinnitus disappeared. Regarding questionnaires, improvement was observed in group I - in 43.11% of ears, in group II - 32.8%. In both groups audiometric improvement of hearing was recognized. (1) Electrical stimulation of the hearing organ, with the application of current frequencies according to tinnitus frequencies (selective electrical stimulation), was an efficient method in severe tinnitus treatment. (2) Cervical spine kinesitherapy in the treatment of tinnitus, using electrical stimulation, did not have any supporting influence. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Neuromagnetic Index of Hemispheric Asymmetry Prognosticating the Outcome of Sudden Hearing Loss

PubMed Central

Li, Lieber Po-Hung; Shiao, An-Suey; Chen, Kuang-Chao; Lee, Po-Lei; Niddam, David M.; Chang, Shyue-Yih; Hsieh, Jen-Chuen

2012-01-01

The longitudinal relationship between central plastic changes and clinical presentations of peripheral hearing impairment remains unknown. Previously, we reported a unique plastic pattern of “healthy-side dominance” in acute unilateral idiopathic sudden sensorineural hearing loss (ISSNHL). This study aimed to explore whether such hemispheric asymmetry bears any prognostic relevance to ISSNHL along the disease course. Using magnetoencephalography (MEG), inter-hemispheric differences in peak dipole amplitude and latency of N100m to monaural tones were evaluated in 21 controls and 21 ISSNHL patients at two stages: initial and fixed stage (1 month later). Dynamics/Prognostication of hemispheric asymmetry were assessed by the interplay between hearing level/hearing gain and ipsilateral/contralateral ratio (I/C) of N100m latency and amplitude. Healthy-side dominance of N100m amplitude was observed in ISSNHL initially. The pattern changed with disease process. There is a strong correlation between the hearing level at the fixed stage and initial I/Camplitude on affected-ear stimulation in ISSNHL. The optimal cut-off value with the best prognostication effect for the hearing improvement at the fixed stage was an initial I/Clatency on affected-ear stimulation of 1.34 (between subgroups of complete and partial recovery) and an initial I/Clatency on healthy-ear stimulation of 0.76 (between subgroups of partial and no recovery), respectively. This study suggested that a dynamic process of central auditory plasticity can be induced by peripheral lesions. The hemispheric asymmetry at the initial stage bears an excellent prognostic potential for the treatment outcomes and hearing level at the fixed stage in ISSNHL. Our study demonstrated that such brain signature of central auditory plasticity in terms of both N100m latency and amplitude at defined time can serve as a prognostication predictor for ISSNHL. Further studies are needed to explore the long-term temporal scenario of auditory hemispheric asymmetry and to get better psychoacoustic correlates of pathological hemispheric asymmetry in ISSNHL. PMID:22532839

Contralateral suppression of transient-evoked otoacoustic emissions in children with sickle cell disease.

PubMed

Stuart, Andrew; Preast, June L

2012-01-01

In previous studies, otoacoustic emissions (OAEs) have been found to be larger in normal-hearing children with sickle cell disease (SCD). It was hypothesized that some dysfunction or reduction in the medial olivocochlear efferent suppression of outer hair cell activity was responsible for this phenomenon. To test this hypothesis, contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs) was examined in children with and without SCD. Thirteen African American school-aged normal-hearing children with homozygous SCD and 13 age- and gender-matched control children participated. TEOAEs were obtained bilaterally with 80 dB peSPL nonlinear click stimuli. To examine contralateral suppression, TEOAEs were obtained with 60 dB peSPL linear click stimuli with and without a contralateral 65 dB SPL white noise suppressor. Overall and half-octave band TEOAE levels were found to be larger in children with SCD relative to the normal control children (p < 0.05), consistent with previous reports of increased OAE levels. There was no significant difference (p > 0.05) in the absolute or proportional amount of TEOAE suppression as a function of group and ear. There were also no significant correlations or linear predictive relationships between TEOAE suppression and TEOAE level for either ear or group (p > 0.05). These findings do not support the notion that increased OAE levels in children with SCD are a consequence of abnormal medial olivocochlear system function as assessed with contralateral suppression of TEOAEs.

Effects of slow repetitive transcranial magnetic stimulation in patients with corticobasal syndrome.

PubMed

Civardi, Carlo; Pisano, Fabrizio; Delconte, Carmen; Collini, Alessandra; Monaco, Francesco

2015-06-01

Corticobasal syndrome is characterized by asymmetric cortical sensorimotor dysfunction and parkinsonism; an altered cortical excitability has been reported. We explored with transcranial magnetic stimulation the motor cortical excitability in corticobasal syndrome, and the effects of slow repetitive transcranial magnetic stimulation. With transcranial magnetic stimulation, we studied two corticobasal syndrome patients. We determined bilaterally from the first dorsal interosseous muscle: relaxed threshold, and contralateral and ipsilateral silent period. We also evaluated the contralateral silent period after active/sham slow repetitive transcranial magnetic stimulation on the most affected side. At T0 the silent period was bilaterally short. On the most affected side, active slow repetitive transcranial magnetic stimulation induced a short lasting prolongation of the contralateral silent period. In corticobasal syndrome, transcranial magnetic stimulation showed a reduction cortical inhibitory phenomenon potentially reversed transiently by slow repetitive transcranial magnetic stimulation.

Surgical management of polyotia.

PubMed

Pan, Bo; Qie, Shuyan; Zhao, Yanyong; Tang, Xiaojun; Lin, Lin; Yang, Qinghua; Zhuang, Hongxing; Jiang, Haiyue

2010-08-01

Polyotia is an extremely rare type of congenital external ear malformation, which is defined as an accessory ear that is large enough to resemble an additional pinna. The terms 'mirror ear' or 'accessory ear' are sometime used. We present our methods in correcting this malformation and summarise the aetiology. The posterior part of the polyotia may presents with a normal ear, a constricted ear or a microtic ear. Free auricular composite tissue transplantation was used to correct the constricted ear. Ear reconstruction was applied in cases of microtia. The anterior auricle was mainly used to form the tragus. 7 cases polyotia were treated between 2004 and 2008. After free auricular composite tissue transplantation the size of the constricted ear and the contralateral ear was similar. In microtia cases the reconstructed ears were natural looking and had a satisfactory three-dimensional contour. The extra tissue of the anterior ear was excised and the tragus was reconstructed. Through operative intervention tailored to the individual case natural-looking and symmetric ears were acquired. The aetiology of polyotia probably relates to abnormal migration of neural crest cell. Copyright 2009 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Click-Evoked Auditory Efferent Activity: Rate and Level Effects.

PubMed

Boothalingam, Sriram; Kurke, Julianne; Dhar, Sumitrajit

2018-05-07

There currently are no standardized protocols to evaluate auditory efferent function in humans. Typical tests use broadband noise to activate the efferents, but only test the contralateral efferent pathway, risk activating the middle ear muscle reflex (MEMR), and are laborious for clinical use. In an attempt to develop a clinical test of bilateral auditory efferent function, we have designed a method that uses clicks to evoke efferent activity, obtain click-evoked otoacoustic emissions (CEOAEs), and monitor MEMR. This allows for near-simultaneous estimation of cochlear and efferent function. In the present study, we manipulated click level (60, 70, and 80 dB peak-equivalent sound pressure level [peSPL]) and rate (40, 50, and 62.5 Hz) to identify an optimal rate-level combination that evokes measurable efferent modulation of CEOAEs. Our findings (n = 58) demonstrate that almost all click levels and rates used caused significant inhibition of CEOAEs, with a significant interaction between level and rate effects. Predictably, bilateral activation produced greater inhibition compared to stimulating the efferents only in the ipsilateral or contralateral ear. In examining the click rate-level effects during bilateral activation in greater detail, we observed a 1-dB inhibition of CEOAE level for each 10-dB increase in click level, with rate held constant at 62.5 Hz. Similarly, a 10-Hz increase in rate produced a 0.74-dB reduction in CEOAE level, with click level held constant at 80 dB peSPL. The effect size (Cohen's d) was small for either monaural condition and medium for bilateral, faster-rate, and higher-level conditions. We were also able to reliably extract CEOAEs from efferent eliciting clicks. We conclude that clicks can indeed be profitably employed to simultaneously evaluate cochlear health using CEOAEs as well as their efferent modulation. Furthermore, using bilateral clicks allows the evaluation of both the crossed and uncrossed elements of the auditory efferent nervous system, while yielding larger, more discernible, inhibition of the CEOAEs relative to either ipsilateral or contralateral condition.

Masking overshoot: Effects of ipsilateral, bilateral and contralateral priming

NASA Astrophysics Data System (ADS)

Connington, Maureen Catherine

This study was concerned with masking overshoot, the elevation of the threshold of a brief signal when it is presented at the onset of a masking noise rather than at its temporal center. More specifically, it was concerned with the release from overshoot (i.e., threshold improvement) produced by priming stimuli, presented ipsilaterally, bilaterally and contralaterally at primer- masker gaps of 20, 40 and 80 msec. The more general purpose of the study was to assess the contributions of peripheral and central factors to the overshoot and overshoot-release phenomena. The primers and masking stimuli consisted of white noise bursts of 200 and 400 msec duration, respectively. The probe signal was a 20 msec 4kHz tone. The tone and masker were always presented in one ear. There were, however, 3 modes of primer presentation: ipsilateral, bilateral (identical waveforms to both ears) and contralateral. Three primer-masker gaps of 20, 40 and 80 msec were used. Five normally hearing adults were tested at primer and masker levels of 80 dB HL. Four of the five subjects exhibited significant masking overshoot, when tested without priming. Ipsilateral priming with 20 and 40 msec gaps produced significant masking release from overshoot. Threshold became poorer, however with increasing gap duration and with increasing distance of the perceived primer from the test ear (i.e. ipsilateral priming produced better thresholds than did bilateral priming and bilateral priming produced better thresholds than contralateral priming). There was significant masking enhancement (i.e. threshold was significantly poorer than in the unprimed probe at onset condition) with the contralateral 80 msec primer. The fact that ipsilateral and bilateral primers performed differently does not support the theory that masking overshoot and its release are solely the results of peripheral adaptation. In fact, the group results support the conclusion that masking overshoot is influenced by central factors. However, there were marked inter-subject differences. It seems possible that masking overshoot and its release are influenced by both peripheral adaptation effects and central processes and that the balance between the two is subject-dependent.

Immunohistological analysis of eotaxin and RANTES in the model animal of eosinophilic otitis media.

PubMed

Kudo, Naomi; Matsubara, Atsushi; Nishizawa, Hisanori; Miura, Tomoya

2017-05-01

The most crucial clinical problem of Eosinophilic Otitis Media (EOM) is sensorineural hearing loss. A previous report revealed that repeated antigen stimulation of middle ear causes eosinophilic inflammation not only in the middle ear but also in the inner ear. The purpose of the present study was to elucidate the mechanism of eosinophil infiltration to the inner ear in the animal model of EOM. Continuous OVA stimulation to the middle ear of guinea pigs was performed for 7 days, 14 days, and 28 days. Histological observation was made for eosinophil infiltration and morphological change of the inner ear. Immunostaining for eotaxin and RANTES was performed to study immunoreactivity of those chemokines. In the 7-day stimulation side, a few eosinophils were found in the scala tympani, without obvious morphological damage of the inner ear. Moreover, immunoreactivity of both eotaxin and RANTES was significantly higher in the OVA stimulation sides than control sides. For both eotaxin and RANTES, the number of immunopositive cells was significantly increased in the 14-day stimulation side over the 7-day stimulation side. Eotaxin and RANTES seem to play some important roles for the eosinophil infiltration in the middle and inner ear of model animal of EOM.

Contralateral versus ipsilateral rTMS of temporoparietal cortex for the treatment of chronic unilateral tinnitus: comparative study.

PubMed

Khedr, E M; Abo-Elfetoh, N; Rothwell, J C; El-Atar, A; Sayed, E; Khalifa, H

2010-07-01

Repetitive transcranial magnetic stimulation (rTMS) applied over left temporoparietal cortex has been reported to have a long-term therapeutic effect on tinnitus. We compare the impact of 1 and 25 Hz rTMS delivered either contralateral or ipsilateral to symptoms in 62 patients with unilateral chronic tinnitus. Patients were randomly assigned to one of four treatment groups: with stimulation at 1 or 25 Hz applied either ipsilateral or contralateral to symptoms. Two thousand pulses per session were given daily for 2 weeks. Changes in tinnitus handicap inventory (THI), self-rating scores of loudness, awareness, and annoyance were measured monthly for 10 months. Duration of residual inhibition (RI) and psychiatric morbidity were evaluated monthly for 3 months. There was a significant main effect of time (P < 0.0001) and a significant time x side interaction (P = 0.032) between groups. This was because of the fact that contralateral stimulation had a greater effect on THI than ipsilateral stimulation; it was also superior to left side stimulation (P = 0.027). Ratings of loudness improved more after contralateral rTMS (P = 0.037). Twenty patients had no remaining tinnitus after 3 months; the remainder had a significant increase in RI. Patients with the shortest history of tinnitus tended to respond better to rTMS. There was a significant correlation between changes in THI score and changes in Hamilton anxiety and depression scores. Ten daily treatments of 1 and 25 Hz rTMS contralateral to the side of tinnitus have a greater beneficial effect on symptoms than either ipsilateral or left side stimulation.

Sensorineural hearing loss in patients with chronic suppurative otitis media: Is there a significant correlation?

PubMed

Amali, Amin; Hosseinzadeh, Nima; Samadi, Shahram; Nasiri, Shirin; Zebardast, Jayran

2017-02-01

Hearing loss as a sequel of chronic suppurative otitis media (CSOM) is often conductive, but recent studies have found an additional sensorineural component in these patients, thus demonstrating inner ear damage. The aim of the study was to determine the association between CSOM and sensorineural hearing loss (SNHL) and to assess the influence of patient's age, duration of disease, and presence of cholesteatoma and ossicular erosion on the degree of SNHL. In a retrospective study, the medical records of 119 patients who underwent surgery was reviewed. Seventy patients met the inclusion criteria of unilateral otorrhea, normal contralateral ear on otoscopy, and age between 10-65 years with no history of head trauma or ear surgery or familial hearing loss. Bone conduction (BC) thresholds for affected and contralateral ear were measured at frequencies of 500, 1000, 2000, and 4000 Hz. Data analysis was performed using SPSS 13 with independent-samples t-test, Pearson correlation test, and two-tailed analysis. A p ≤ 0.05 was considered statistically significant. Significant higher BC thresholds were found in the affected ear than in the normal ear for each frequency (p < 0.001), which increased with increasing frequency (7.00 dB at the 500 Hz and 9.71 dB at the 4000 Hz). There was a significant correlation between age and degree of SNHL (r = 0.422, p < 0.001) but no significant correlation was in duration of the disease (r = 0.119, p > 0.05). There was no relationship between presence of cholesteatoma and ossicular erosion with SNHL (p > 0.05). These findings demonstrate that CSOM is associated with some degree of SNHL and cochlear damage, and higher frequencies are more affected. Aging can act as a precipitating factor in this pathological process.

Contralateral-noise effects on cochlear responses in anesthetized mice are dominated by feedback from an unknown pathway

PubMed Central

Usubuchi, Hajime; Vetter, Douglas E.; Elgoyhen, A. Bélen; Thomas, Steven A.; Liberman, M. Charles

2012-01-01

Suppression of ipsilateral distortion product otoacoustic emissions (DPOAEs) by contralateral noise is used in humans and animals to assay the strength of sound-evoked negative feedback from the medial olivocochlear (MOC) efferent pathway. However, depending on species and anesthesia, contributions of other feedback systems to the middle or inner ear can cloud the interpretation. Here, contributions of MOC and middle-ear muscle reflexes, as well as autonomic feedback, to contra-noise suppression in anesthetized mice are dissected by selectively eliminating each pathway by surgical transection, pharmacological blockade, or targeted gene deletion. When ipsilateral DPOAEs were evoked by low-level primaries, contra-noise suppression was typically ∼1 dB with contra-noise levels around 95 dB SPL, and it always disappeared upon contralateral cochlear destruction. Lack of middle-ear muscle contribution was suggested by persistence of contra-noise suppression after paralysis with curare, tensor tympani cauterization, or section of the facial nerve. Contribution of cochlear sympathetics was ruled out by studying mutant mice lacking adrenergic signaling (dopamine β-hydroxylase knockouts). Surprisingly, contra-noise effects on low-level DPOAEs were also not diminished by eliminating the MOC system pharmacologically (strychnine), surgically, or by deletion of relevant cholinergic receptors (α9/α10). In contrast, when ipsilateral DPOAEs were evoked by high-level primaries, the contra-noise suppression, although comparable in magnitude, was largely eliminated by MOC blockade or section. Possible alternate pathways are discussed for the source of contra-noise-evoked effects at low ipsilateral levels. PMID:22514298

Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions.

PubMed

Kalaiah, Mohan Kumar; Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

2017-04-01

The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using 'linear' clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the contralateral ear. While, in condition 2, speech was embedded into white noise at +3, -3, and -9 dB signal-to-noise ratio (SNR) and delivered to the contralateral ear. The SNR was varied to investigate the effect of listening effort on the CSTEOAE. In condition 3, speech was played backwards and embedded into white noise at -3 dB SNR. The conditions 1 and 3 served as passive listening condition and the condition 2 served as active listening condition. In active listening condition, the participants categorized the words in to two groups (e.g., animal and vehicle). CSTEOAE was found to be largest in the presence of white noise, and the amount of CSTEOAE was not significantly different between active and passive listening conditions (condition 2 and 3). Listening effort had an effect on the CSTEOAE, the amount of suppression increased with listening effort, when SNR was decreased from +3 dB to -3 dB. However, when the SNR was further reduced to -9 dB, there was no further increase in the amount of CSTEOAE, instead there was a reduction in the amount of suppression. The findings of the present study show that listening effort might affect CSTEOAE.

Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions

PubMed Central

Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

2017-01-01

Background and Objectives The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Subjects and Methods Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using ‘linear’ clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the contralateral ear. While, in condition 2, speech was embedded into white noise at +3, −3, and −9 dB signal-to-noise ratio (SNR) and delivered to the contralateral ear. The SNR was varied to investigate the effect of listening effort on the CSTEOAE. In condition 3, speech was played backwards and embedded into white noise at −3 dB SNR. The conditions 1 and 3 served as passive listening condition and the condition 2 served as active listening condition. In active listening condition, the participants categorized the words in to two groups (e.g., animal and vehicle). Results CSTEOAE was found to be largest in the presence of white noise, and the amount of CSTEOAE was not significantly different between active and passive listening conditions (condition 2 and 3). Listening effort had an effect on the CSTEOAE, the amount of suppression increased with listening effort, when SNR was decreased from +3 dB to −3 dB. However, when the SNR was further reduced to −9 dB, there was no further increase in the amount of CSTEOAE, instead there was a reduction in the amount of suppression. Conclusions The findings of the present study show that listening effort might affect CSTEOAE. PMID:28417101

Combined Electric and Acoustic Stimulation With Hearing Preservation: Effect of Cochlear Implant Low-Frequency Cutoff on Speech Understanding and Perceived Listening Difficulty.

PubMed

Gifford, René H; Davis, Timothy J; Sunderhaus, Linsey W; Menapace, Christine; Buck, Barbara; Crosson, Jillian; O'Neill, Lori; Beiter, Anne; Segel, Phil

The primary objective of this study was to assess the effect of electric and acoustic overlap for speech understanding in typical listening conditions using semidiffuse noise. This study used a within-subjects, repeated measures design including 11 experienced adult implant recipients (13 ears) with functional residual hearing in the implanted and nonimplanted ear. The aided acoustic bandwidth was fixed and the low-frequency cutoff for the cochlear implant (CI) was varied systematically. Assessments were completed in the R-SPACE sound-simulation system which includes a semidiffuse restaurant noise originating from eight loudspeakers placed circumferentially about the subject's head. AzBio sentences were presented at 67 dBA with signal to noise ratio varying between +10 and 0 dB determined individually to yield approximately 50 to 60% correct for the CI-alone condition with full CI bandwidth. Listening conditions for all subjects included CI alone, bimodal (CI + contralateral hearing aid), and bilateral-aided electric and acoustic stimulation (EAS; CI + bilateral hearing aid). Low-frequency cutoffs both below and above the original "clinical software recommendation" frequency were tested for all patients, in all conditions. Subjects estimated listening difficulty for all conditions using listener ratings based on a visual analog scale. Three primary findings were that (1) there was statistically significant benefit of preserved acoustic hearing in the implanted ear for most overlap conditions, (2) the default clinical software recommendation rarely yielded the highest level of speech recognition (1 of 13 ears), and (3) greater EAS overlap than that provided by the clinical recommendation yielded significant improvements in speech understanding. For standard-electrode CI recipients with preserved hearing, spectral overlap of acoustic and electric stimuli yielded significantly better speech understanding and less listening effort in a laboratory-based, restaurant-noise simulation. In conclusion, EAS patients may derive more benefit from greater acoustic and electric overlap than given in current software fitting recommendations, which are based solely on audiometric threshold. These data have larger scientific implications, as previous studies may not have assessed outcomes with optimized EAS parameters, thereby underestimating the benefit afforded by hearing preservation.

TMS activation of interhemispheric pathways between the posterior parietal cortex and the contralateral motor cortex

PubMed Central

Koch, Giacomo; Ruge, Diane; Cheeran, Binith; Fernandez Del Olmo, Miguel; Pecchioli, Cristiano; Marconi, Barbara; Versace, Viviana; Lo Gerfo, Emanuele; Torriero, Sara; Oliveri, Massimiliano; Caltagirone, Carlo; Rothwell, John C

2009-01-01

Using a twin coil transcranial magnetic stimulation (tc-TMS) approach we have previously demonstrated that facilitation may be detected in the primary motor cortex (M1) following stimulation over the ipsilateral caudal intraparietal sulcus (cIPS). Here we tested the interhemispheric interactions between the IPS and the contralateral motor cortex (M1). We found that conditioning the right cIPS facilitated contralateral M1 when the conditioning stimulus had an intensity of 90% resting motor threshold (RMT) but not at 70% or 110% RMT. Facilitation was maximal when the interstimulus interval (ISI) between cIPS and M1 was 6 or 12 ms. These facilitatory effects were mediated by interactions with specific groups of interneurons in the contralateral M1. In fact, short intracortical inhibition (SICI) was reduced following cIPS stimulation. Moreover, additional comparison of facilitation of responses evoked by anterior–posterior versus posterior–anterior stimulation of M1 suggested that facilitation was more effective on early I1/I2 circuits than on I3 circuits. In contrast to these effects, stimulation of anterior IPS (aIPS) at 90% RMT induced inhibition, instead of facilitation, of contralateral M1 at ISIs of 10–12 ms. Finally, we found similar facilitation between left cIPS and right M1 although the conditioning stimuli had to have a higher intensity compared with stimulation of right cIPS (110% instead of 90% RMT). These findings demonstrate that different subregions of the posterior parietal cortex (PPC) in humans exert both facilitatory and inhibitory effects towards the contralateral primary motor cortex. These corticocortical projections could contribute to a variety of motor tasks such as bilateral manual coordination, movement planning in space and grasping. PMID:19622612

Contralaterally Controlled Functional Electrical Stimulation for Stroke Rehabilitation

PubMed Central

Knutson, Jayme S.; Harley, Mary Y.; Hisel, Terri Z.; Makowski, Nathaniel S.; Fu, Michael J.; Chae, John

2012-01-01

Contralaterally controlled functional electrical stimulation (CCFES) is an innovative method of delivering neuromuscular electrical stimulation for rehabilitation of paretic limbs after stroke. It is being studied to evaluate its efficacy in improving recovery of arm and hand function and ankle dorsiflexion in chronic and subacute stroke patients. The initial studies provide preliminary evidence supporting the efficacy of CCFES. PMID:23365893

Deep Brain Stimulation of Heschl Gyrus: Implantation Technique, Intraoperative Localization, and Effects of Stimulation.

PubMed

Donovan, Chris; Sweet, Jennifer; Eccher, Matthew; Megerian, Cliff; Semaan, Maroun; Murray, Gail; Miller, Jonathan

2015-12-01

Tinnitus is a source of considerable morbidity, and neuromodulation has been shown to be a potential treatment option. However, the location of the primary auditory cortex within Heschl gyrus in the temporal operculum presents challenges for targeting and electrode implantation. To determine whether anatomic targeting with intraoperative verification using evoked potentials can be used to implant electrodes directly into the Heschl gyrus (HG). Nine patients undergoing stereo-electroencephalogram evaluation for epilepsy were enrolled. HG was directly targeted on volumetric magnetic resonance imaging, and framed stereotaxy was used to implant an electrode parallel to the axis of the gyrus by using an oblique anterolateral-posteromedial trajectory. Intraoperative evoked potentials from auditory stimuli were recorded from multiple electrode contacts. Postoperatively, stimulation of each electrode was performed and participants were asked to describe the percept. Audiometric analysis was performed for 2 participants during subthreshold stimulation. Sounds presented to the contralateral and ipsilateral ears produced evoked potentials in HG electrodes in all participants intraoperatively. Stimulation produced a reproducible sensation of sound in all participants with perceived volume proportional to amplitude. Four participants reported distinct sounds when different electrodes were stimulated, with more medial contacts producing tones perceived as higher in pitch. Stimulation was not associated with adverse audiometric effects. There were no complications of electrode implantation. Direct anatomic targeting with physiological verification can be used to implant electrodes directly into primary auditory cortex. If deep brain stimulation proves effective for intractable tinnitus, this technique may be useful to assist with electrode implantation. DBS, deep brain stimulatorEEG, electroencephalographyHG, Heschl gyrus.

Real-time loudness normalisation with combined cochlear implant and hearing aid stimulation

PubMed Central

Van Eeckhoutte, Maaike; Van Deun, Lieselot; Francart, Tom

2018-01-01

Background People who use a cochlear implant together with a contralateral hearing aid—so-called bimodal listeners—have poor localisation abilities and sounds are often not balanced in loudness across ears. In order to address the latter, a loudness balancing algorithm was created, which equalises the loudness growth functions for the two ears. The algorithm uses loudness models in order to continuously adjust the two signals to loudness targets. Previous tests demonstrated improved binaural balance, improved localisation, and better speech intelligibility in quiet for soft phonemes. In those studies, however, all stimuli were preprocessed so spontaneous head movements and individual head-related transfer functions were not taken into account. Furthermore, the hearing aid processing was linear. Study design In the present study, we simplified the acoustical loudness model and implemented the algorithm in a real-time system. We tested bimodal listeners on speech perception and on sound localisation, both in normal loudness growth configuration and in a configuration with a modified loudness growth function. We also used linear and compressive hearing aids. Results The comparison between the original acoustical loudness model and the new simplified model showed loudness differences below 3% for almost all tested speech-like stimuli and levels. We found no effect of balancing the loudness growth across ears for speech perception ability in quiet and in noise. We found some small improvements in localisation performance. Further investigation with a larger sample size is required. PMID:29617421

Frontal Eye Fields Control Attentional Modulation of Alpha and Gamma Oscillations in Contralateral Occipitoparietal Cortex

PubMed Central

O'Shea, Jacinta; Jensen, Ole; Bergmann, Til O.

2015-01-01

Covertly directing visuospatial attention produces a frequency-specific modulation of neuronal oscillations in occipital and parietal cortices: anticipatory alpha (8–12 Hz) power decreases contralateral and increases ipsilateral to attention, whereas stimulus-induced gamma (>40 Hz) power is boosted contralaterally and attenuated ipsilaterally. These modulations must be under top-down control; however, the control mechanisms are not yet fully understood. Here we investigated the causal contribution of the human frontal eye field (FEF) by combining repetitive transcranial magnetic stimulation (TMS) with subsequent magnetoencephalography. Following inhibitory theta burst stimulation to the left FEF, right FEF, or vertex, participants performed a visual discrimination task requiring covert attention to either visual hemifield. Both left and right FEF TMS caused marked attenuation of alpha modulation in the occipitoparietal cortex. Notably, alpha modulation was consistently reduced in the hemisphere contralateral to stimulation, leaving the ipsilateral hemisphere relatively unaffected. Additionally, right FEF TMS enhanced gamma modulation in left visual cortex. Behaviorally, TMS caused a relative slowing of response times to targets contralateral to stimulation during the early task period. Our results suggest that left and right FEF are causally involved in the attentional top-down control of anticipatory alpha power in the contralateral visual system, whereas a right-hemispheric dominance seems to exist for control of stimulus-induced gamma power. These findings contrast the assumption of primarily intrahemispheric connectivity between FEF and parietal cortex, emphasizing the relevance of interhemispheric interactions. The contralaterality of effects may result from a transient functional reorganization of the dorsal attention network after inhibition of either FEF. PMID:25632139

Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

PubMed

Kawaguchi, Jun; Matsuura, Nobuyuki; Kasahara, Masataka; Ichinohe, Tatsuya

2015-02-01

The purpose of this study was to investigate the latency and amplitude of trigeminal somatosensory evoked potentials to clarify how nerve function on the contralateral side is affected after cervical sympathetic block (CSB). Subjects comprised 16 volunteers. For CSB, the tip of a needle was contacted with the transverse process of the sixth cervical vertebra on the right side, and lidocaine was injected. Trigeminal somatosensory evoked potentials were recorded bilaterally from C5/C6 scalp positions. Pupil diameters were also measured. Electrical stimulations were applied to the left-side lower lip, and trigeminal somatosensory evoked potentials waveforms derived from both sides of the scalp were recorded. Then, electrical stimulations were applied to the right-side of the lower lip, and recording was again performed. Recordings were performed at 5, 15, and 30 minutes after CSB. On the CSB side, pupil diameter decreased at 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials at contralateral stimulation showed a prolongation of the latency in both P20 and N25 components on bilateral recording sites 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials' amplitude at contralateral stimulation was smaller than at ipsilateral stimulation 5 minutes after CSB. Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

When avoidance leads to approach: how ear preference interacts with neuroticism to predict disinhibited approach.

PubMed

Jackson, Chris J

2008-07-01

A series of eight studies focuses on how the avoidance system represented by neuroticism can lead to disinhibited approach tendencies. Based on research which argues that hemispheric preferences predispose the left hemisphere to fast action goal formation, and contralateral pathways between ear and brain, it is proposed that (a) people with a right ear preference will engage in fast action goal formation and (b) disinhibited approach results from neurotic people who reduce anxiety by means of fast action goal formation. Study 1 provides evidence from telesales operators of a link between self-rated ear preference and objective ear preference and provides evidence that disinhibited approach is predicted by a neuroticismxear preference interaction. Studies 2, 3, and 4 provide evidence that ear preference is related to other measures of objective aural preference and action goal formation. Studies 5, 6, 7, and 8 provide evidence that the neuroticismxear preference interaction predicts a variety of different disinhibited approach tendencies.

Relation between measures of speech-in-noise performance and measures of efferent activity

NASA Astrophysics Data System (ADS)

Smith, Brad; Harkrider, Ashley; Burchfield, Samuel; Nabelek, Anna

2003-04-01

Individual differences in auditory perceptual abilities in noise are well documented but the factors causing such variability are unclear. The purpose of this study was to determine if individual differences in responses measured from the auditory efferent system were correlated to individual variations in speech-in-noise performance. The relation between behavioral performance on three speech-in-noise tasks and two objective measures of the efferent auditory system were examined in thirty normal-hearing, young adults. Two of the speech-in-noise tasks measured an acceptable noise level, the maximum level of speech-babble noise that a subject is willing to accept while listening to a story. For these, the acceptable noise level was evaluated using both an ipsilateral (story and noise in same ear) and a contralateral (story and noise in opposite ears) paradigm. The third speech-in-noise task evaluated speech recognition using monosyllabic words presented in competing speech babble. Auditory efferent activity was assessed by examining the resulting suppression of click-evoked otoacoustic emissions following the introduction of a contralateral, broad-band stimulus and the activity of the ipsilateral and contralateral acoustic reflex arc was evaluated using tones and broad-band noise. Results will be discussed relative to current theories of speech in noise performance and auditory inhibitory processes.

Cervical Vestibular-Evoked Myogenic Potentials: Norms and Protocols

PubMed Central

Isaradisaikul, Suwicha; Navacharoen, Niramon; Hanprasertpong, Charuk; Kangsanarak, Jaran

2012-01-01

Vestibular-evoked myogenic potential (VEMP) testing is a vestibular function test used for evaluating saccular and inferior vestibular nerve function. Parameters of VEMP testing include VEMP threshold, latencies of p1 and n1, and p1-n1 interamplitude. Less commonly used parameters were p1-n1 interlatency, interaural difference of p1 and n1 latency, and interaural amplitude difference (IAD) ratio. This paper recommends using air-conducted 500 Hz tone burst auditory stimulation presented monoaurally via an inserted ear phone while the subject is turning his head to the contralateral side in the sitting position and recording the responses from the ipsilateral sternocleidomastoid muscle. Normative values of VEMP responses in 50 normal audiovestibular volunteers were presented. VEMP testing protocols and normative values in other literature were reviewed and compared. The study is beneficial to clinicians as a reference guide to set up VEMP testing and interpretation of the VEMP responses. PMID:22577386

[Speech perception with electric-acoustic stimulation : Comparison with bilateral cochlear implant users in different noise conditions].

PubMed

Rader, T

2015-02-01

Cochlear implantation with the aim of hearing preservation for combined electric-acoustic stimulation (EAS) is the therapy of choice for patients with residual low-frequency hearing. Preserved residual acoustic hearing has a positive effect on speech intelligibility in difficult noise conditions. The goal of this study was to assess speech reception thresholds in various complex noise conditions for patients with EAS in comparison with patients using bilateral cochlear implants (CI). Speech perception in noise was measured for bilateral CI and EAS patient groups. A total of 22 listeners with normal hearing served as a control group. Speech reception thresholds (SRT) were measured using a closed-set sentence matrix test. Speech was presented with a single source in frontal position; noise was presented in frontal position or in a multisource noise field (MSNF) consisting of a four-loudspeaker array with independent noise sources. Modulated speech-simulating noise and pseudocontinuous noise served respectively as interference signal with different temporal characteristics. The average SRTs in the EAS group were significantly better in all test conditions than those of the group with bilateral CI. Both user groups showed significant improvement in the MSNF condition compared with the frontal noise condition as a result of bilateral interaction. The normal-hearing control group was able to use short temporal gaps in modulated noise to improve speech perception in noise (gap listening). This effect was absent in both implanted user groups. Patients with combined EAS in one ear and a hearing aid in the contralateral ear show significantly improved speech perception in complex noise conditions compared with bilateral CI recipients.

Single-session tDCS over the dominant hemisphere affects contralateral spectral EEG power, but does not enhance neurofeedback-guided event-related desynchronization of the non-dominant hemisphere's sensorimotor rhythm.

PubMed

Mondini, Valeria; Mangia, Anna Lisa; Cappello, Angelo

2018-01-01

Transcranial direct current stimulation (tDCS) and neurofeedback-guided motor imagery (MI) have attracted considerable interest in neurorehabilitation, given their ability to influence neuroplasticity. As tDCS has been shown to modulate event-related desynchronization (ERD), the neural signature of motor imagery detected for neurofeedback, a combination of the techniques was recently proposed. One limitation of this approach is that the area targeted for stimulation is the same from which the signal for neurofeedback is acquired. As tDCS may interfere with proximal electroencephalographic (EEG) electrodes, in this study our aim was to test whether contralateral tDCS could have interhemispheric effects on the spectral power of the unstimulated hemisphere, possibly mediated by transcallosal connection, and whether such effects could be used to enhance ERD magnitudes. A contralateral stimulation approach would indeed facilitate co-registration, as the stimulation electrode would be far from the recording sites. Twenty right-handed healthy volunteers (aged 21 to 32) participated in the study: ten assigned to cathodal, ten to anodal versus sham stimulation. We applied stimulation over the dominant (left) hemisphere, and assessed ERD and spectral power over the non-dominant (right) hemisphere. The effect of tDCS was evaluated over time. Spectral power was assessed in theta, alpha and beta bands, under both rest and MI conditions, while ERD was evaluated in alpha and beta bands. Two main findings emerged: (1) contralateral alpha-ERD was reduced after anodal (p = 0.0147), but not enhanced after cathodal tDCS; (2) both stimulations had remote effects on the spectral power of the contralateral hemisphere, particularly in theta and alpha (significant differences in the topographical t-value maps). The absence of contralateral cathodal ERD enhancement suggests that the protocol is not applicable in the context of MI training. Nevertheless, ERD results of anodal and spectral power results of both stimulations complement recent findings on the distant tDCS effects between functionally related areas.

Single-session tDCS over the dominant hemisphere affects contralateral spectral EEG power, but does not enhance neurofeedback-guided event-related desynchronization of the non-dominant hemisphere's sensorimotor rhythm

PubMed Central

Mangia, Anna Lisa; Cappello, Angelo

2018-01-01

Background and objective Transcranial direct current stimulation (tDCS) and neurofeedback-guided motor imagery (MI) have attracted considerable interest in neurorehabilitation, given their ability to influence neuroplasticity. As tDCS has been shown to modulate event-related desynchronization (ERD), the neural signature of motor imagery detected for neurofeedback, a combination of the techniques was recently proposed. One limitation of this approach is that the area targeted for stimulation is the same from which the signal for neurofeedback is acquired. As tDCS may interfere with proximal electroencephalographic (EEG) electrodes, in this study our aim was to test whether contralateral tDCS could have interhemispheric effects on the spectral power of the unstimulated hemisphere, possibly mediated by transcallosal connection, and whether such effects could be used to enhance ERD magnitudes. A contralateral stimulation approach would indeed facilitate co-registration, as the stimulation electrode would be far from the recording sites. Methods Twenty right-handed healthy volunteers (aged 21 to 32) participated in the study: ten assigned to cathodal, ten to anodal versus sham stimulation. We applied stimulation over the dominant (left) hemisphere, and assessed ERD and spectral power over the non-dominant (right) hemisphere. The effect of tDCS was evaluated over time. Spectral power was assessed in theta, alpha and beta bands, under both rest and MI conditions, while ERD was evaluated in alpha and beta bands. Results Two main findings emerged: (1) contralateral alpha-ERD was reduced after anodal (p = 0.0147), but not enhanced after cathodal tDCS; (2) both stimulations had remote effects on the spectral power of the contralateral hemisphere, particularly in theta and alpha (significant differences in the topographical t-value maps). Conclusion The absence of contralateral cathodal ERD enhancement suggests that the protocol is not applicable in the context of MI training. Nevertheless, ERD results of anodal and spectral power results of both stimulations complement recent findings on the distant tDCS effects between functionally related areas. PMID:29513682

Measurements of evoked electroencephalograph by transcranial magnetic stimulation applied to motor cortex and posterior parietal cortex

NASA Astrophysics Data System (ADS)

Iwahashi, Masakuni; Koyama, Yohei; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo; Iramina, Keiji

2009-04-01

To investigate the functional connectivity, the evoked potentials by stimulating at the motor cortex, the posterior parietal cortex, and the cerebellum by transcranial magnetic stimulation (TMS) were measured. It is difficult to measure the evoked electroencephalograph (EEG) by the magnetic stimulation because of the large artifact induced by the magnetic pulse. We used an EEG measurement system with sample-and-hold circuit and an independent component analysis to eliminate the electromagnetic interaction emitted from TMS. It was possible to measure EEG signals from all electrodes over the head within 10 ms after applying the TMS. When the motor area was stimulated by TMS, the spread of evoked electrical activity to the contralateral hemisphere was observed at 20 ms after stimulation. However, when the posterior parietal cortex was stimulated, the evoked electrical activity to the contralateral hemisphere was not observed. When the cerebellum was stimulated, the cortical activity propagated from the stimulated point to the frontal area and the contralateral hemisphere at around 20 ms after stimulation. These results suggest that the motor area has a strong interhemispheric connection and the posterior parietal cortex has no interhemispheric connection.

Frontal eye fields control attentional modulation of alpha and gamma oscillations in contralateral occipitoparietal cortex.

PubMed

Marshall, Tom R; O'Shea, Jacinta; Jensen, Ole; Bergmann, Til O

2015-01-28

Covertly directing visuospatial attention produces a frequency-specific modulation of neuronal oscillations in occipital and parietal cortices: anticipatory alpha (8-12 Hz) power decreases contralateral and increases ipsilateral to attention, whereas stimulus-induced gamma (>40 Hz) power is boosted contralaterally and attenuated ipsilaterally. These modulations must be under top-down control; however, the control mechanisms are not yet fully understood. Here we investigated the causal contribution of the human frontal eye field (FEF) by combining repetitive transcranial magnetic stimulation (TMS) with subsequent magnetoencephalography. Following inhibitory theta burst stimulation to the left FEF, right FEF, or vertex, participants performed a visual discrimination task requiring covert attention to either visual hemifield. Both left and right FEF TMS caused marked attenuation of alpha modulation in the occipitoparietal cortex. Notably, alpha modulation was consistently reduced in the hemisphere contralateral to stimulation, leaving the ipsilateral hemisphere relatively unaffected. Additionally, right FEF TMS enhanced gamma modulation in left visual cortex. Behaviorally, TMS caused a relative slowing of response times to targets contralateral to stimulation during the early task period. Our results suggest that left and right FEF are causally involved in the attentional top-down control of anticipatory alpha power in the contralateral visual system, whereas a right-hemispheric dominance seems to exist for control of stimulus-induced gamma power. These findings contrast the assumption of primarily intrahemispheric connectivity between FEF and parietal cortex, emphasizing the relevance of interhemispheric interactions. The contralaterality of effects may result from a transient functional reorganization of the dorsal attention network after inhibition of either FEF. Copyright © 2015 the authors 0270-6474/15/351638-10$15.00/0.

Diversity of bilateral synaptic assemblies for binaural computation in midbrain single neurons.

PubMed

He, Na; Kong, Lingzhi; Lin, Tao; Wang, Shaohui; Liu, Xiuping; Qi, Jiyao; Yan, Jun

2017-11-01

Binaural hearing confers many beneficial functions but our understanding of its underlying neural substrates is limited. This study examines the bilateral synaptic assemblies and binaural computation (or integration) in the central nucleus of the inferior colliculus (ICc) of the auditory midbrain, a key convergent center. Using in-vivo whole-cell patch-clamp, the excitatory and inhibitory postsynaptic potentials (EPSPs/IPSPs) of single ICc neurons to contralateral, ipsilateral and bilateral stimulation were recorded. According to the contralateral and ipsilateral EPSP/IPSP, 7 types of bilateral synaptic assemblies were identified. These include EPSP-EPSP (EE), E-IPSP (EI), E-no response (EO), II, IE, IO and complex-mode (CM) neurons. The CM neurons showed frequency- and/or amplitude-dependent EPSPs/IPSPs to contralateral or ipsilateral stimulation. Bilateral stimulation induced EPSPs/IPSPs that could be larger than (facilitation), similar to (ineffectiveness) or smaller than (suppression) those induced by contralateral stimulation. Our findings have allowed our group to characterize novel neural circuitry for binaural computation in the midbrain. Copyright © 2017 Elsevier B.V. All rights reserved.

Interhemispheric transfer time in patients with auditory hallucinations: an auditory event-related potential study.

PubMed

Henshall, Katherine R; Sergejew, Alex A; McKay, Colette M; Rance, Gary; Shea, Tracey L; Hayden, Melissa J; Innes-Brown, Hamish; Copolov, David L

2012-05-01

Central auditory processing in schizophrenia patients with a history of auditory hallucinations has been reported to be impaired, and abnormalities of interhemispheric transfer have been implicated in these patients. This study examined interhemispheric functional connectivity between auditory cortical regions, using temporal information obtained from latency measures of the auditory N1 evoked potential. Interhemispheric Transfer Times (IHTTs) were compared across 3 subject groups: schizophrenia patients who had experienced auditory hallucinations, schizophrenia patients without a history of auditory hallucinations, and normal controls. Pure tones and single-syllable words were presented monaurally to each ear, while EEG was recorded continuously. IHTT was calculated for each stimulus type by comparing the latencies of the auditory N1 evoked potential recorded contralaterally and ipsilaterally to the ear of stimulation. The IHTTs for pure tones did not differ between groups. For word stimuli, the IHTT was significantly different across the 3 groups: the IHTT was close to zero in normal controls, was highest in the AH group, and was negative (shorter latencies ipsilaterally) in the nonAH group. Differences in IHTTs may be attributed to transcallosal dysfunction in the AH group, but altered or reversed cerebral lateralization in nonAH participants is also possible. Copyright © 2012 Elsevier B.V. All rights reserved.

Informational masking of speech in children: Effects of ipsilateral and contralateral distracters

NASA Astrophysics Data System (ADS)

Wightman, Frederic L.; Kistler, Doris J.

2005-11-01

Using a closed-set speech recognition paradigm thought to be heavily influenced by informational masking, auditory selective attention was measured in 38 children (ages 4-16 years) and 8 adults (ages 20-30 years). The task required attention to a monaural target speech message that was presented with a time-synchronized distracter message in the same ear. In some conditions a second distracter message or a speech-shaped noise was presented to the other ear. Compared to adults, children required higher target/distracter ratios to reach comparable performance levels, reflecting more informational masking in these listeners. Informational masking in most conditions was confirmed by the fact that a large proportion of the errors made by the listeners were contained in the distracter message(s). There was a monotonic age effect, such that even the children in the oldest age group (13.6-16 years) demonstrated poorer performance than adults. For both children and adults, presentation of an additional distracter in the contralateral ear significantly reduced performance, even when the distracter messages were produced by a talker of different sex than the target talker. The results are consistent with earlier reports from pure-tone masking studies that informational masking effects are much larger in children than in adults.

A Longitudinal Study in Children With Sequential Bilateral Cochlear Implants: Time Course for the Second Implanted Ear and Bilateral Performance.

PubMed

Reeder, Ruth M; Firszt, Jill B; Cadieux, Jamie H; Strube, Michael J

2017-01-01

Whether, and if so when, a second-ear cochlear implant should be provided to older, unilaterally implanted children is an ongoing clinical question. This study evaluated rate of speech recognition progress for the second implanted ear and with bilateral cochlear implants in older sequentially implanted children and evaluated localization abilities. A prospective longitudinal study included 24 bilaterally implanted children (mean ear surgeries at 5.11 and 14.25 years). Test intervals were every 3-6 months through 24 months postbilateral. Test conditions were each ear and bilaterally for speech recognition and localization. Overall, the rate of progress for the second implanted ear was gradual. Improvements in quiet continued through the second year of bilateral use. Improvements in noise were more modest and leveled off during the second year. On all measures, results from the second ear were poorer than the first. Bilateral scores were better than either ear alone for all measures except sentences in quiet and localization. Older sequentially implanted children with several years between surgeries may obtain speech understanding in the second implanted ear; however, performance may be limited and rate of progress gradual. Continued contralateral ear hearing aid use and reduced time between surgeries may enhance outcomes.

A Binaural Cochlear Implant Sound Coding Strategy Inspired by the Contralateral Medial Olivocochlear Reflex

PubMed Central

Eustaquio-Martín, Almudena; Stohl, Joshua S.; Wolford, Robert D.; Schatzer, Reinhold; Wilson, Blake S.

2016-01-01

Objectives: In natural hearing, cochlear mechanical compression is dynamically adjusted via the efferent medial olivocochlear reflex (MOCR). These adjustments probably help understanding speech in noisy environments and are not available to the users of current cochlear implants (CIs). The aims of the present study are to: (1) present a binaural CI sound processing strategy inspired by the control of cochlear compression provided by the contralateral MOCR in natural hearing; and (2) assess the benefits of the new strategy for understanding speech presented in competition with steady noise with a speech-like spectrum in various spatial configurations of the speech and noise sources. Design: Pairs of CI sound processors (one per ear) were constructed to mimic or not mimic the effects of the contralateral MOCR on compression. For the nonmimicking condition (standard strategy or STD), the two processors in a pair functioned similarly to standard clinical processors (i.e., with fixed back-end compression and independently of each other). When configured to mimic the effects of the MOCR (MOC strategy), the two processors communicated with each other and the amount of back-end compression in a given frequency channel of each processor in the pair decreased/increased dynamically (so that output levels dropped/increased) with increases/decreases in the output energy from the corresponding frequency channel in the contralateral processor. Speech reception thresholds in speech-shaped noise were measured for 3 bilateral CI users and 2 single-sided deaf unilateral CI users. Thresholds were compared for the STD and MOC strategies in unilateral and bilateral listening conditions and for three spatial configurations of the speech and noise sources in simulated free-field conditions: speech and noise sources colocated in front of the listener, speech on the left ear with noise in front of the listener, and speech on the left ear with noise on the right ear. In both bilateral and unilateral listening, the electrical stimulus delivered to the test ear(s) was always calculated as if the listeners were wearing bilateral processors. Results: In both unilateral and bilateral listening conditions, mean speech reception thresholds were comparable with the two strategies for colocated speech and noise sources, but were at least 2 dB lower (better) with the MOC than with the STD strategy for spatially separated speech and noise sources. In unilateral listening conditions, mean thresholds improved with increasing the spatial separation between the speech and noise sources regardless of the strategy but the improvement was significantly greater with the MOC strategy. In bilateral listening conditions, thresholds improved significantly with increasing the speech-noise spatial separation only with the MOC strategy. Conclusions: The MOC strategy (1) significantly improved the intelligibility of speech presented in competition with a spatially separated noise source, both in unilateral and bilateral listening conditions; (2) produced significant spatial release from masking in bilateral listening conditions, something that did not occur with fixed compression; and (3) enhanced spatial release from masking in unilateral listening conditions. The MOC strategy as implemented here, or a modified version of it, may be usefully applied in CIs and in hearing aids. PMID:26862711

A Binaural Cochlear Implant Sound Coding Strategy Inspired by the Contralateral Medial Olivocochlear Reflex.

PubMed

Lopez-Poveda, Enrique A; Eustaquio-Martín, Almudena; Stohl, Joshua S; Wolford, Robert D; Schatzer, Reinhold; Wilson, Blake S

2016-01-01

In natural hearing, cochlear mechanical compression is dynamically adjusted via the efferent medial olivocochlear reflex (MOCR). These adjustments probably help understanding speech in noisy environments and are not available to the users of current cochlear implants (CIs). The aims of the present study are to: (1) present a binaural CI sound processing strategy inspired by the control of cochlear compression provided by the contralateral MOCR in natural hearing; and (2) assess the benefits of the new strategy for understanding speech presented in competition with steady noise with a speech-like spectrum in various spatial configurations of the speech and noise sources. Pairs of CI sound processors (one per ear) were constructed to mimic or not mimic the effects of the contralateral MOCR on compression. For the nonmimicking condition (standard strategy or STD), the two processors in a pair functioned similarly to standard clinical processors (i.e., with fixed back-end compression and independently of each other). When configured to mimic the effects of the MOCR (MOC strategy), the two processors communicated with each other and the amount of back-end compression in a given frequency channel of each processor in the pair decreased/increased dynamically (so that output levels dropped/increased) with increases/decreases in the output energy from the corresponding frequency channel in the contralateral processor. Speech reception thresholds in speech-shaped noise were measured for 3 bilateral CI users and 2 single-sided deaf unilateral CI users. Thresholds were compared for the STD and MOC strategies in unilateral and bilateral listening conditions and for three spatial configurations of the speech and noise sources in simulated free-field conditions: speech and noise sources colocated in front of the listener, speech on the left ear with noise in front of the listener, and speech on the left ear with noise on the right ear. In both bilateral and unilateral listening, the electrical stimulus delivered to the test ear(s) was always calculated as if the listeners were wearing bilateral processors. In both unilateral and bilateral listening conditions, mean speech reception thresholds were comparable with the two strategies for colocated speech and noise sources, but were at least 2 dB lower (better) with the MOC than with the STD strategy for spatially separated speech and noise sources. In unilateral listening conditions, mean thresholds improved with increasing the spatial separation between the speech and noise sources regardless of the strategy but the improvement was significantly greater with the MOC strategy. In bilateral listening conditions, thresholds improved significantly with increasing the speech-noise spatial separation only with the MOC strategy. The MOC strategy (1) significantly improved the intelligibility of speech presented in competition with a spatially separated noise source, both in unilateral and bilateral listening conditions; (2) produced significant spatial release from masking in bilateral listening conditions, something that did not occur with fixed compression; and (3) enhanced spatial release from masking in unilateral listening conditions. The MOC strategy as implemented here, or a modified version of it, may be usefully applied in CIs and in hearing aids.

Neural Correlates of the Antinociceptive Effects of Stimulating the Anterior Pretectal Nucleus in Rats.

PubMed

Genaro, Karina; Prado, Wiliam A

2016-11-01

Stimulation-evoked antinociception (SEA) from the anterior pretectal nucleus (APtN) activates mechanisms that descend to the spinal cord through the dorsolateral funiculus, but the encephalic route followed by the descending pathways from the APtN is not completely known. This study evaluated the changes in the SEA from the APtN in the Wistar rat tail-flick test after lidocaine-induced neural block or N-methyl-d-aspartate-induced neurotoxic lesion of the deep mesencephalic nucleus (DpMe), tegmental pedunculopontine nucleus (PPTg), or lateral paragigantocellular nucleus (LPGi). The SEA from the APtN was less intense after neural block of the contralateral DpMe or PPTg or the ipsilateral LPGi, but was not changed by the neural block of the ipsilateral DpMe or PPTg or the contralateral LPGi. Antinociception did not occur when APtN stimulation was carried out 5 minutes after lidocaine or 6 days after N-methyl-d-aspartate injections into the contralateral DpMe and the ipsilateral LPGi, or into the contralateral PPTg and the ipsilateral LPGi. We conclude that the SEA from the APtN activates 2 descending pain inhibitory pathways, one relaying in the ipsilateral LPGi and another relaying sequentially in the contralateral DpMe and PPTg. The antinociceptive effect of the APtN stimulation involves 2 descending pathways: one relaying in the ipsilateral LPGi and another descending contralaterally via relays in the DpMe and PPTg. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Ear Asymmetry for Monaurally Presented Word Lists in Children and Adults.

ERIC Educational Resources Information Center

Burns, Kathy Martindale; Manning, Walter H.

1985-01-01

To study ear asymmetry during monaural stimulation, 80 listeners were asked to recall the word which followed a probe word in 40 10-word lists. Ear asymmetry during monaural stimulation appeared to be related to competition between incoming and rehearsed stimuli during central memory processing. (Author/CL)

Mirror ear: a reconstructive technique for substantial tragal anomalies or polyotia.

PubMed

Gore, Sinclair M; Myers, Simon R; Gault, David

2006-01-01

Polyotia (mirror ear) is an extremely rarely reported congenital anomaly of the external ear. The aetiology of this condition is unclear, and there are few descriptions of surgical techniques used. We aimed to review our experience with this condition by performing a retrospective review of the cases treated in our unit. Eight cases of polyotia treated at a referral centre for ear reconstruction in a 12 year period (1992-2004) were reviewed. Patient demographic data and associated syndromes were recorded. Operative techniques used in the cases were studied. There was an equal number of males and females. Four patients had abnormal contralateral ears and two patients were formally diagnosed as suffering from a congenital developmental syndrome. Five main components of surgical technique were found to be particularly relevant to these cases. These relate to deconstruction of the defect, management of extra cartilage, management of skin, proximity of the facial nerve and the timing of surgery. The authors conclude that a structured surgical approach can lead to successful reconstruction of these difficult abnormalities.

Tumbling cartilage flap and free auricular composite tissue transplantation for correcting mild and moderate forms of constricted ear.

PubMed

Pan, Bo; Zhao, Yanyong; Zhuang, Hongxing; Lin, Lin; Liu, Lei; Jiang, Haiyue

2010-01-01

To report a new surgical approach that results in a natural size and contour of the external malformed constricted ear. A total of 62 consecutive patients with constricted ear underwent surgery between July 1, 2005, and December 31, 2007. Depending on the features and severity of the deformity, the methods of tumbling cartilage flap (CF), free auricular composite graft, or a combination of these 2 techniques were applied. A total of 45 patients were treated with the method of tumbling CF. Twelve were treated with an auricular composite graft from the contralateral ear, and in 5 patients a combination of the 2 methods was used. In all cases, there was an improvement in the size, shape, and symmetry of the ears, and most patients were satisfied with the outcome. Complications were rare, and there was no donor site deformity. The technique of tumbling CF and free auricular composite graft provides a simple and promising treatment for constricted ears. Furthermore, this technique is easy to apply with a predictable good outcome.

Objective speech transmission improvements with a binaural cochlear implant sound-coding strategy inspired by the contralateral medial olivocochlear reflex.

PubMed

Lopez-Poveda, Enrique A; Eustaquio-Martín, Almudena

2018-04-01

It has been recently shown that cochlear implant users could enjoy better speech reception in noise and enhanced spatial unmasking with binaural audio processing inspired by the inhibitory effects of the contralateral medial olivocochlear (MOC) reflex on compression [Lopez-Poveda, Eustaquio-Martin, Stohl, Wolford, Schatzer, and Wilson (2016). Ear Hear. 37, e138-e148]. The perceptual evidence supporting those benefits, however, is limited to a few target-interferer spatial configurations and to a particular implementation of contralateral MOC inhibition. Here, the short-term objective intelligibility index is used to (1) objectively demonstrate potential benefits over many more spatial configurations, and (2) investigate if the predicted benefits may be enhanced by using more realistic MOC implementations. Results corroborate the advantages and drawbacks of MOC processing indicated by the previously published perceptual tests. The results also suggest that the benefits may be enhanced and the drawbacks overcome by using longer time constants for the activation and deactivation of inhibition and, to a lesser extent, by using a comparatively greater inhibition in the lower than in the higher frequency channels. Compared to using two functionally independent processors, the better MOC processor improved the signal-to-noise ratio in the two ears between 1 and 6 decibels by enhancing head-shadow effects, and was advantageous for all tested target-interferer spatial configurations.

A Systematic Review of Electric-Acoustic Stimulation

PubMed Central

Ching, Teresa Y. C.; Cowan, Robert

2013-01-01

Cochlear implant systems that combine electric and acoustic stimulation in the same ear are now commercially available and the number of patients using these devices is steadily increasing. In particular, electric-acoustic stimulation is an option for patients with severe, high frequency sensorineural hearing impairment. There have been a range of approaches to combining electric stimulation and acoustic hearing in the same ear. To develop a better understanding of fitting practices for devices that combine electric and acoustic stimulation, we conducted a systematic review addressing three clinical questions: what is the range of acoustic hearing in the implanted ear that can be effectively preserved for an electric-acoustic fitting?; what benefits are provided by combining acoustic stimulation with electric stimulation?; and what clinical fitting practices have been developed for devices that combine electric and acoustic stimulation? A search of the literature was conducted and 27 articles that met the strict evaluation criteria adopted for the review were identified for detailed analysis. The range of auditory thresholds in the implanted ear that can be successfully used for an electric-acoustic application is quite broad. The effectiveness of combined electric and acoustic stimulation as compared with electric stimulation alone was consistently demonstrated, highlighting the potential value of preservation and utilization of low frequency hearing in the implanted ear. However, clinical procedures for best fitting of electric-acoustic devices were varied. This clearly identified a need for further investigation of fitting procedures aimed at maximizing outcomes for recipients of electric-acoustic devices. PMID:23539259

Source analysis of auditory steady-state responses in acoustic and electric hearing.

PubMed

Luke, Robert; De Vos, Astrid; Wouters, Jan

2017-02-15

Speech is a complex signal containing a broad variety of acoustic information. For accurate speech reception, the listener must perceive modulations over a range of envelope frequencies. Perception of these modulations is particularly important for cochlear implant (CI) users, as all commercial devices use envelope coding strategies. Prolonged deafness affects the auditory pathway. However, little is known of how cochlear implantation affects the neural processing of modulated stimuli. This study investigates and contrasts the neural processing of envelope rate modulated signals in acoustic and CI listeners. Auditory steady-state responses (ASSRs) are used to study the neural processing of amplitude modulated (AM) signals. A beamforming technique is applied to determine the increase in neural activity relative to a control condition, with particular attention paid to defining the accuracy and precision of this technique relative to other tomographies. In a cohort of 44 acoustic listeners, the location, activity and hemispheric lateralisation of ASSRs is characterised while systematically varying the modulation rate (4, 10, 20, 40 and 80Hz) and stimulation ear (right, left and bilateral). We demonstrate a complex pattern of laterality depending on both modulation rate and stimulation ear that is consistent with, and extends, existing literature. We present a novel extension to the beamforming method which facilitates source analysis of electrically evoked auditory steady-state responses (EASSRs). In a cohort of 5 right implanted unilateral CI users, the neural activity is determined for the 40Hz rate and compared to the acoustic cohort. Results indicate that CI users activate typical thalamic locations for 40Hz stimuli. However, complementary to studies of transient stimuli, the CI population has atypical hemispheric laterality, preferentially activating the contralateral hemisphere. Copyright © 2016. Published by Elsevier Inc.

Differences in the suppression of distortion product otoacoustic emissions by contralateral white noise between patients with acute or chronic tinnitus.

PubMed

Riga, Maria; Komis, Agis; Marangoudakis, Pavlos; Naxakis, Stefanos; Ferekidis, Eleftherios; Kandiloros, Dimitrios; Danielides, Vasilios

2017-08-01

The mechanisms underlying the shift from acute tinnitus to chronic remain obscure. An association between tinnitus and medial olivocochlear bundle (MOCB) reflex dysfunction has been hypothesised by several studies. The differences between participants with acute and chronic tinnitus have not yet been investigated. Participants were examined with distortion product otoacoustic emissions (DPOAEs) suppression elicited by contralateral white noise. They were compared in terms of frequency regions with non-recordable DPOAEs, suppression amplitudes and the presence of DPOAE enhancement. Eighteen participants with acute tinnitus, 40 age-matched adults with chronic tinnitus and 17 controls were included. All participants (aged 34.7 ± 9.6years; mean ± Standard deviation) had normal hearing. Tinnitus was bilateral in 22 participants and unilateral in 36. Ears with chronic tinnitus presented significantly lower DPOAE suppression amplitudes than ears with acute tinnitus (p < 0.0001). Both acute and chronic tinnitus ears present a high prevalence of enhancement, significantly different from controls (p < 0.0001, p = 0.0002, respectively). Non-recordable DPOAEs were significantly more frequent in the chronic than in the acute tinnitus and control groups (p < 0.0001). The differences between study groups indicate that when tinnitus becomes chronic, DPOAEs suppression presents changes that might reveal corresponding steps in tinnitus pathophysiology. Treatment implications are discussed.

Automatic gain control of neural coupling during cooperative hand movements.

PubMed

Thomas, F A; Dietz, V; Schrafl-Altermatt, M

2018-04-13

Cooperative hand movements (e.g. opening a bottle) are controlled by a task-specific neural coupling, reflected in EMG reflex responses contralateral to the stimulation site. In this study the contralateral reflex responses in forearm extensor muscles to ipsilateral ulnar nerve stimulation was analyzed at various resistance and velocities of cooperative hand movements. The size of contralateral reflex responses was closely related to the level of forearm muscle activation required to accomplish the various cooperative hand movement tasks. This indicates an automatic gain control of neural coupling that allows a rapid matching of corrective forces exerted at both sides of an object with the goal 'two hands one action'.

Interaural delay sensitivity and the classification of low best-frequency binaural responses in the inferior colliculus of the guinea pig.

PubMed

McAlpine, D; Jiang, D; Palmer, A R

1996-08-01

Monaural and binaural response properties of single units in the inferior colliculus (IC) of the guinea pig were investigated. Neurones were classified according to the effect of monaural stimulation of either ear alone and the effect of binaural stimulation. The majority (309/334) of IC units were excited (E) by stimulation of the contralateral ear, of which 41% (127/309) were also excited by monaural ipsilateral stimulation (EE), and the remainder (182/309) were unresponsive to monaural ipsilateral stimulation (EO). For units with best frequencies (BF) up to 3 kHz, similar proportions of EE and EO units were observed. Above 3 kHz, however, significantly more EO than EE units were observed. Units were also classified as either facilitated (F), suppressed (S), or unaffected (O) by binaural stimulation. More EO than EE units were suppressed or unaffected by binaural stimulation, and more EE than EO units were facilitated. There were more EO/S units above 1.5 kHz than below. Binaural beats were used to examine the interaural delay sensitivity of low-BF (BF < 1.5 kHz) units. The distributions of preferred interaural phases and, by extension, interaural delays, resembled those seen in other species, and those obtained using static interaural delays in the IC of the guinea pig. Units with best phase (BP) angles closer to zero generally showed binaural facilitation, whilst those with larger BPs generally showed binaural suppression. The classification of units based upon binaural stimulation with BF tones was consistent with their interaural-delay sensitivity. Characteristic delays (CD) were examined for 96 low-BF units. A clear relationship between BF and CD was observed. CDs of units with very low BFs (< 200 Hz) were long and positive, becoming progressively shorter as BF increased until, for units with BFs between 400 and 800 Hz, the majority of CDs were negative. Above 800 Hz, both positive and negative CDs were observed. A relationship between CD and characteristic phase (CP) was also observed, with CPs increasing in value as CDs became more negative. These results demonstrate that binaural processing in the guinea pig at low frequencies is similar to that reported in all other species studied. However, the dependence of CD on BF would suggest that the delay line system that sets up the interaural-delay sensitivity in the lower brainstem varies across frequency as well as within each frequency band.

Comparison of forward (ear-canal) and reverse (round-window) sound stimulation of the cochlea.

PubMed

Stieger, Christof; Rosowski, John J; Nakajima, Hideko Heidi

2013-07-01

The cochlea is normally driven with "forward" stimulation, in which sound is introduced to the ear canal. Alternatively, the cochlea can be stimulated at the round window (RW) using an actuator. During RW "reverse" stimulation, the acoustic flow starting at the RW does not necessarily take the same path as during forward stimulation. To understand the differences between forward and reverse stimulation, we measured ear-canal pressure, stapes velocity, RW velocity, and intracochlear pressures in scala vestibuli (SV) and scala tympani (ST) of fresh human temporal bones. During forward stimulation, the cochlear drive (differential pressure across the partition) results from the large difference in magnitude between the pressures of SV and ST, which occurs due to the high compliance of the RW. During reverse stimulation, the relatively high impedance of the middle ear causes the pressures of SV and ST to have similar magnitudes, and the differential pressure results primarily from the difference in phase of the pressures. Furthermore, the sound path differs between forward and reverse stimulation, such that motion through a third window is more significant during reverse stimulation. Additionally, we determined that although stapes velocity is a good estimate of cochlear drive during forward stimulation, it is not a good measure during reverse stimulation. This article is part of a special issue entitled "MEMRO 2012". Copyright © 2012 Elsevier B.V. All rights reserved.

Oxidative metabolic products released from polymorphonuclear leukocytes in middle ear fluid during experimental pneumococcal otitis media.

PubMed Central

Kawana, M; Kawana, C; Yokoo, T; Quie, P G; Giebink, G S

1991-01-01

To determine whether oxidative metabolic products of phagocytic cells are present in the middle ear during experimental pneumococcal otitis media, we measured the concentration of myeloperoxidase (MPO) in middle ear fluid (MEF) and the capacity of neutrophils isolated from MEF and peripheral blood to produce MPO and superoxide anion (O2-) after in vitro stimulation. Free MPO in MEF was significantly increased 24 and 48 h after either viable or nonviable pneumococci were inoculated into the middle ear. In vitro-stimulated production of MPO and O2- from middle ear neutrophils was significantly less than that from peripheral blood neutrophils 24 h after nonviable pneumococci were inoculated but similar to it after 48 h. Twenty-four hours after viable pneumococci were inoculated, middle ear neutrophils stimulated in vitro produced less MPO but the same amount of O2- as did blood neutrophils. Oxidative metabolic products, therefore, are released from phagocytic cells into the MEF during pneumococcal otitis media, and future studies will need to define the contribution of these products to acute and chronic middle ear tissue injury. PMID:1657782

An experimental study of inner ear injury in an animal model of eosinophilic otitis media.

PubMed

Matsubara, Atsushi; Nishizawa, Hisanori; Kurose, Akira; Nakagawa, Takashi; Takahata, Junko; Sasaki, Akira

2014-03-01

As the periods of intratympanic injection of ovalbumin (OVA) to the middle ear became longer, marked eosinophil infiltration in the perilymphatic space was observed. Moreover severe morphological damage of the organ of Corti was observed in the 28-day antigen-stimulation side. These results indicate that eosinophilic inflammation occurred in the inner ear and caused profound hearing loss. The purpose of the present study was to elucidate the inner ear damage in a new animal model of eosinophilic otitis media (EOM) which we recently constructed. We constructed the animal model of EOM by intraperitoneal and intratympanic injection of OVA. Infiltrating cells and the inner ear damage were examined by histological study. In the inner ear, a few eosinophils were seen in the scala tympani of the organ of Corti and the dilation of capillaries of the stria vascularis was observed in the 7-day stimulation side. In the 14-day antigen stimulation side, some eosinophils and macrophages were seen in not only the scala tympani but also the scala vestibule. In the 28-day antigen-stimulation side, severe morphological damage of the organ of Corti and many eosinophils, red blood cells, and plasma cells infiltrating the perilymph were observed.

Mechanisms of Cochlear Stimulation Through the Round Window

NASA Astrophysics Data System (ADS)

Lukashkin, Andrei N.; Weddell, Thomas; Russell, Ian J.

2011-11-01

The round window membrane (RW) functions as a pressure relief valve in conventional hearing allowing structures of the middle ear to move. Investigations in recent years have shown that middle ear implants can be used to stimulate the cochlea via the RW. Isolated clinical uses of this technique have been applied but more thorough theoretical and empirical studies are required. Using guinea pigs as test subjects we have investigated physiological effects of RW stimulation using a simulation of active middle ear prosthesis, a cylindrical neodymium iron boron disk magnet placed upon the RW which can be stimulated by an electromagnetic coil positioned in close proximity to the magnet.

Study of Methylene Blue Ototoxicity in the Guinea Pig.

PubMed

Belhassen, Sarah; Alzahrani, Musaed; Nader, Marc-Elie; Gaboury, Louis; Saliba, Issam

2017-11-01

Methylene blue is widely used in the medical field, especially as a blue dye for staining. It is also used as a photosensitizing agent in antimicrobial photodynamic therapy, which once photoactivated is effective for the eradication of several multi-resistant bacteria. The objective of this study was to investigate the ototoxic potential of methylene blue and precise its use in otology. It was a prospective animal study performed on guinea pigs in our tertiary medical center. We divided the animals into two groups: an experimental group and a control group, who underwent a series of three intratympanic (IT) injections. In the control group (n = 10), they received injections of gentamicin in one ear (positive control) and normal saline in the contralateral ear (negative control). The experimental group (n = 10) received injections of methylene blue in one ear, compared to injections of normal saline in the contralateral ear. We conducted auditory-evoked brainstem response (ABR) before and 1 week after the injection series. Once this is completed, the cochlea was dissected and caspase-3 was analyzed by immunohistochemistry. The mean difference of hearing loss in the methylene blue group compared to normal saline was 1.50 dB, and it was not shown to be statistically significant (P = 0.688). For the positive control group, which received IT injections of gentamicin, the mean threshold of hearing loss difference for all the frequencies combined was 66.25 dB (P < 0.001). Furthermore, uptake of caspase-3 by immunohistochemistry (apoptotic marker) was negative in our group, which received injections of methylene blue. In light of our results, IT injections of methylene blue did not demonstrate an ototoxic potential. We recommend further studies to precise its use in the otologic field.

Study of Methylene Blue Ototoxicity in the Guinea Pig

PubMed Central

Belhassen, Sarah; Alzahrani, Musaed; Nader, Marc-Elie; Gaboury, Louis; Saliba, Issam

2017-01-01

Background Methylene blue is widely used in the medical field, especially as a blue dye for staining. It is also used as a photosensitizing agent in antimicrobial photodynamic therapy, which once photoactivated is effective for the eradication of several multi-resistant bacteria. The objective of this study was to investigate the ototoxic potential of methylene blue and precise its use in otology. Methods It was a prospective animal study performed on guinea pigs in our tertiary medical center. We divided the animals into two groups: an experimental group and a control group, who underwent a series of three intratympanic (IT) injections. In the control group (n = 10), they received injections of gentamicin in one ear (positive control) and normal saline in the contralateral ear (negative control). The experimental group (n = 10) received injections of methylene blue in one ear, compared to injections of normal saline in the contralateral ear. We conducted auditory-evoked brainstem response (ABR) before and 1 week after the injection series. Once this is completed, the cochlea was dissected and caspase-3 was analyzed by immunohistochemistry. Results The mean difference of hearing loss in the methylene blue group compared to normal saline was 1.50 dB, and it was not shown to be statistically significant (P = 0.688). For the positive control group, which received IT injections of gentamicin, the mean threshold of hearing loss difference for all the frequencies combined was 66.25 dB (P < 0.001). Furthermore, uptake of caspase-3 by immunohistochemistry (apoptotic marker) was negative in our group, which received injections of methylene blue. Conclusion In light of our results, IT injections of methylene blue did not demonstrate an ototoxic potential. We recommend further studies to precise its use in the otologic field. PMID:29038666

Auditory enhancement of increments in spectral amplitude stems from more than one source.

PubMed

Carcagno, Samuele; Semal, Catherine; Demany, Laurent

2012-10-01

A component of a test sound consisting of simultaneous pure tones perceptually "pops out" if the test sound is preceded by a copy of itself with that component attenuated. Although this "enhancement" effect was initially thought to be purely monaural, it is also observable when the test sound and the precursor sound are presented contralaterally (i.e., to opposite ears). In experiment 1, we assessed the magnitude of ipsilateral and contralateral enhancement as a function of the time interval between the precursor and test sounds (10, 100, or 600 ms). The test sound, randomly transposed in frequency from trial to trial, was followed by a probe tone, either matched or mismatched in frequency to the test sound component which was the target of enhancement. Listeners' ability to discriminate matched probes from mismatched probes was taken as an index of enhancement magnitude. The results showed that enhancement decays more rapidly for ipsilateral than for contralateral precursors, suggesting that ipsilateral enhancement and contralateral enhancement stem from at least partly different sources. It could be hypothesized that, in experiment 1, contralateral precursors were effective only because they provided attentional cues about the target tone frequency. In experiment 2, this hypothesis was tested by presenting the probe tone before the precursor sound rather than after the test sound. Although the probe tone was then serving as a frequency cue, contralateral precursors were again found to produce enhancement. This indicates that contralateral enhancement cannot be explained by cuing alone and is a genuine sensory phenomenon.

Tympanoplasty for Chronic Tympanic Membrane Perforation in Children: Systematic Review and Meta-analysis.

PubMed

Hardman, John; Muzaffar, Jameel; Nankivell, Paul; Coulson, Chris

2015-06-01

To study the effectiveness of Type 1 tympanoplasty for chronic tympanic membrane perforations in the pediatric age group and to investigate factors influencing its success. Searches were conducted of the MEDLINE database and the Cochrane Database of Systematic Reviews using terms focused around tympanoplasty and children. Searches were performed on June 23, 2014 and limited to English language entries since January 1, 1997. Studies reporting tympanoplasty closure rates in children 18 years and younger, with a minimum follow-up of 6 months, were included. Studies focusing on more advanced forms of tympanoplasty and revision surgery were excluded. Five hundred sixty-four articles were screened identifying 2,609 cases from 45 eligible studies. Data were collected by consensus of the first two authors with the third author arbitrating disparities of opinion. Success was taken as the closure rate at 12 months where possible. Forest plots with Mantel-Haenszel analyses were used to compare closure rates with respect to perforation size, adenoidectomy, status of contralateral ear, Eustachian tube function, active infection, and graft position. Linear regression and Fisher's exact were used to analyze closure rate with respect to age. The mean weighted closure rate for pediatric tympanoplasty was 83.4%. Subgroup analysis found age not to be a significant factor affecting the closure rate. Tympanoplasties performed on larger perforations or in children with abnormal contralateral ear findings were more likely to fail. Surgery may be best delayed until contralateral otitis media with effusion has settled.

Acoustic stimulation on the round window for active middle ear implants.

PubMed

Seong, Kiwoong; Lee, Kyuyup; Puria, Sunil; Cho, Jin-Ho

2018-06-01

Many clinical reports have discussed the effectiveness of stimulating the ear's round window (RW) with a tool to mitigate conductive and mixed hearing loss. The RW is one of the two openings from the middle ear into the inner ear. Various methods have been proposed to construct a highly efficient, easily implanted, and reliable RW transducer. Devices, however, such as floating mass transducers, have difficulty establishing proper contact without some degree of bone incision around the RW. Additionally, vibration energy may not be fully transmitted to the cochlea, but instead will be spread through the soft tissue around the transducer. We propose a more direct RW stimulation with very high acoustical impedance using a receiver that is a volume velocity source. We expect this source to overcome large acoustic impedance by maximizing sound pressure in a confined space, the RW niche. To verify the effectiveness of the proposed method, ear canal pressure, RW pressure, and stapes velocity are measured by acoustic RW stimulation of human temporal bones. Copyright © 2018 Elsevier Ltd. All rights reserved.

Interictal and Postictal Performances on Dichotic Listening Test in Children with Focal Epilepsy

ERIC Educational Resources Information Center

Carlsson, G.; Wiegand, G.; Stephani, U.

2011-01-01

Dichotic listening test (DL) is an important tool to disclose speech dominance in healthy subjects and in clinical cases. The aim of this study was to probe if focal epilepsy in children reveals a corresponding suppression of the ear reports contralateral to seizure onset site. Thus, 15 children and adolescents with clinically and…

Cortical Auditory Evoked Potentials to Evaluate Cochlear Implant Candidacy in an Ear With Long-standing Hearing Loss: A Case Report.

PubMed

Patel, Tirth R; Shahin, Antoine J; Bhat, Jyoti; Welling, D Bradley; Moberly, Aaron C

2016-10-01

We describe a novel use of cortical auditory evoked potentials in the preoperative workup to determine ear candidacy for cochlear implantation. A 71-year-old male was evaluated who had a long-deafened right ear, had never worn a hearing aid in that ear, and relied heavily on use of a left-sided hearing aid. Electroencephalographic testing was performed using free field auditory stimulation of each ear independently with pure tones at 1000 and 2000 Hz at approximately 10 dB above pure-tone thresholds for each frequency and for each ear. Mature cortical potentials were identified through auditory stimulation of the long-deafened ear. The patient underwent successful implantation of that ear. He experienced progressively improving aided pure-tone thresholds and binaural speech recognition benefit (AzBio score of 74%). Findings suggest that use of cortical auditory evoked potentials may serve a preoperative role in ear selection prior to cochlear implantation. © The Author(s) 2016.

Cochlear implantation with hearing preservation yields significant benefit for speech recognition in complex listening environments.

PubMed

Gifford, René H; Dorman, Michael F; Skarzynski, Henryk; Lorens, Artur; Polak, Marek; Driscoll, Colin L W; Roland, Peter; Buchman, Craig A

2013-01-01

The aim of this study was to assess the benefit of having preserved acoustic hearing in the implanted ear for speech recognition in complex listening environments. The present study included a within-subjects, repeated-measures design including 21 English-speaking and 17 Polish-speaking cochlear implant (CI) recipients with preserved acoustic hearing in the implanted ear. The patients were implanted with electrodes that varied in insertion depth from 10 to 31 mm. Mean preoperative low-frequency thresholds (average of 125, 250, and 500 Hz) in the implanted ear were 39.3 and 23.4 dB HL for the English- and Polish-speaking participants, respectively. In one condition, speech perception was assessed in an eight-loudspeaker environment in which the speech signals were presented from one loudspeaker and restaurant noise was presented from all loudspeakers. In another condition, the signals were presented in a simulation of a reverberant environment with a reverberation time of 0.6 sec. The response measures included speech reception thresholds (SRTs) and percent correct sentence understanding for two test conditions: CI plus low-frequency hearing in the contralateral ear (bimodal condition) and CI plus low-frequency hearing in both ears (best-aided condition). A subset of six English-speaking listeners were also assessed on measures of interaural time difference thresholds for a 250-Hz signal. Small, but significant, improvements in performance (1.7-2.1 dB and 6-10 percentage points) were found for the best-aided condition versus the bimodal condition. Postoperative thresholds in the implanted ear were correlated with the degree of electric and acoustic stimulation (EAS) benefit for speech recognition in diffuse noise. There was no reliable relationship among measures of audiometric threshold in the implanted ear nor elevation in threshold after surgery and improvement in speech understanding in reverberation. There was a significant correlation between interaural time difference threshold at 250 Hz and EAS-related benefit for the adaptive speech reception threshold. The findings of this study suggest that (1) preserved low-frequency hearing improves speech understanding for CI recipients, (2) testing in complex listening environments, in which binaural timing cues differ for signal and noise, may best demonstrate the value of having two ears with low-frequency acoustic hearing, and (3) preservation of binaural timing cues, although poorer than observed for individuals with normal hearing, is possible after unilateral cochlear implantation with hearing preservation and is associated with EAS benefit. The results of this study demonstrate significant communicative benefit for hearing preservation in the implanted ear and provide support for the expansion of CI criteria to include individuals with low-frequency thresholds in even the normal to near-normal range.

Anatomical influences on internally coupled ears in reptiles.

PubMed

Young, Bruce A

2016-10-01

Many reptiles, and other vertebrates, have internally coupled ears in which a patent anatomical connection allows pressure waves generated by the displacement of one tympanic membrane to propagate (internally) through the head and, ultimately, influence the displacement of the contralateral tympanic membrane. The pattern of tympanic displacement caused by this internal coupling can give rise to novel sensory cues. The auditory mechanics of reptiles exhibit more anatomical variation than in any other vertebrate group. This variation includes structural features such as diverticula and septa, as well as coverings of the tympanic membrane. Many of these anatomical features would likely influence the functional significance of the internal coupling between the tympanic membranes. Several of the anatomical components of the reptilian internally coupled ear are under active motor control, suggesting that in some reptiles the auditory system may be more dynamic than previously recognized.

Planer orientation of the bilateral semicircular canals in dizzy patients.

PubMed

Aoki, Sachiko; Takei, Yasuhiko; Suzuki, Kazufumi; Masukawa, Ai; Arai, Yasuko

2012-10-01

Recent development of 3-dimensional analysis of eye movement enabled to detect the eye rotation axis, which is used to determine the responsible semicircular canal(s) in dizzy patients. Therefore, the knowledge of anatomical orientation of bilateral semicircular canals is essential, as all 6 canals influence the eye movements. Employing the new head coordinate system suitable for MR imaging, we calculated the angles of semicircular canal planes of both ears in 11 dizzy patients who had normal caloric response in both ears. The angles between adjacent canal pairs were nearly perpendicular in both ears. The angle between the posterior canal planes and head sagittal plane was 51° and significantly larger the angle between the anterior canal planes and head sagittal plane, which was 35°. The angle between the horizontal canal plane and head sagittal plane was almost orthogonal. Pairs of contralateral synergistic canal planes were not parallel, forming 10° between right and left horizontal canal planes, 17° between right anterior and left posterior canal planes and 19° between the right posterior and left anterior canal planes. Our measurement of the angles of adjacent canal pairs and the angle between each semicircular canal and head sagittal plane coincided with those of previous reports obtained from CT images and skull specimens. However, the angles between contralateral synergistic canal planes were more parallel than those of previous reports. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The unpredictability of lymphatic drainage from the ear in melanoma patients, and its implications for management.

PubMed

Peach, Howard S; van der Ploeg, Augustinus P T; Haydu, Lauren E; Stretch, Jonathan R; Shannon, Kerwin F; Uren, Roger F; Thompson, John F

2013-05-01

The ear is known to have variable lymphatic drainage. The purpose of this study was to define better the lymphatic drainage patterns of the ear by correlating the location of primary tumors, classified according to the embryologically derived anatomical subunits of the ear, with their mapped sentinel nodes (SNs) identified by lymphoscintigraphy (LS). Lymphatic drainage data for patients with a primary melanoma of the ear were reviewed and correlated with the precise primary melanoma site. Between 1993 and 2010, LS was performed in 111 patients with a primary melanoma on the ear, identifying 281 SNs in 195 lymph node (LN) fields. The mean numbers of SNs and LN fields identified by LS per patient were 2.65 and 1.76. SN biopsy was performed in 71 patients (64 %). The mean number of SNs removed was 2.36. The 111 ear melanomas were mostly located on the helical rim (55 %), followed by the lobule (24.3 %). The five different primary ear sites drained mainly to SNs in level CII, level CV and the preauricular region. Drainage was most often to level CII (36.4 %). Drainage to the contralateral neck was not observed. Lymphatic drainage of the ear has no predictable pattern and can be to SNs anywhere in the ipsilateral neck. Most commonly drainage is to cervical level II and the preauricular and postauricular LN fields. LS defines the lymphatic drainage pattern in individual melanoma patients and is essential for accurate SN identification and reliable SN biopsy.

An Objective Estimation of Air-Bone-Gap in Cochlear Implant Recipients with Residual Hearing Using Electrocochleography.

PubMed

Koka, Kanthaiah; Saoji, Aniket A; Attias, Joseph; Litvak, Leonid M

2017-01-01

Although, cochlear implants (CI) traditionally have been used to treat individuals with bilateral profound sensorineural hearing loss, a recent trend is to implant individuals with residual low-frequency hearing. Notably, many of these individuals demonstrate an air-bone gap (ABG) in low-frequency, pure-tone thresholds following implantation. An ABG is the difference between audiometric thresholds measured using air conduction (AC) and bone conduction (BC) stimulation. Although, behavioral AC thresholds are straightforward to assess, BC thresholds can be difficult to measure in individuals with severe-to-profound hearing loss because of vibrotactile responses to high-level, low-frequency stimulation and the potential contribution of hearing in the contralateral ear. Because of these technical barriers to measuring behavioral BC thresholds in implanted patients with residual hearing, it would be helpful to have an objective method for determining ABG. This study evaluated an innovative technique for measuring electrocochleographic (ECochG) responses using the cochlear microphonic (CM) response to assess AC and BC thresholds in implanted patients with residual hearing. Results showed high correlations between CM thresholds and behavioral audiograms for AC and BC conditions, thereby demonstrating the feasibility of using ECochG as an objective tool for quantifying ABG in CI recipients.

Sensory nerve crush and regeneration and the receptive fields and response properties of neurons in the primary somatosensory cerebral cortex of cats.

PubMed

Brandenberg, G A; Mann, M D

1989-03-01

Extracellular recordings were made of activity evoked in neurons of the forepaw focus of somatosensory cerebral cortex by electrical stimulation of each paw in control cats and cats that had undergone crush injury of all cutaneous sensory nerves to the contralateral forepaw 31 to 63 days previously. Neurons responding only to stimulation of the contralateral forepaw were classified as sa; neurons responding to stimulation of both forepaws were classified as sb; neurons responding to stimulation of both contralateral paws were classified as sc; and neurons responding to stimulation of at least three paws were classified as m. The ratio sa:sb:sc:m neurons was 46:3:0:0 in control cats and 104:15:3:26 in cats that had undergone nerve crush 1-2 months prior to study. sa neurons from experimental cats had depth distributions similar to those in controls and responded to contralateral forepaw stimulation with more spikes per discharge, longer latency, and higher threshold than sa neurons in control cats. m neurons from experimental cats were distributed deeper in the cortex than sa neurons, and, when compared to experimental sa neurons, they responded with longer latency and poorer frequency-following ability; however, the number of spikes per discharge and threshold were not significantly different. The appearance of wide-field neurons in this tissue may be explained in terms of strengthening of previously sub-threshold inputs to neurons in the somatosensory system. If the neurons in sensory cortex play a requisite role in cutaneous sensations and if changes similar to those reported here occur and persist in human cortex after nerve crush, then "complete" recovery of sensation in such patients may occur against a background of changed cortical neuronal responsiveness.

Do the angle and length of the eustachian tube influence the development of chronic otitis media?

PubMed

Dinç, Aykut Erdem; Damar, Murat; Uğur, Mehmet Birol; Öz, Ibrahim Ilker; Eliçora, Sultan Şevik; Bişkin, Sultan; Tutar, Hakan

2015-09-01

To compare the eustachian tube (ET) angle (ETa) and length (ETl) of ears with and without chronic otitis media (COM), and to determine the relationship between ET anatomy and the development of COM. A retrospective case-control study. The study group comprised 125 patients (age range, 8-79 years; 64 males and 61 females) with 124 normal ears and 126 diseased ears, including ears with chronic suppurative otitis media (CSOM) with central perforation, intratympanic tympanosclerosis (ITTS), cholesteatoma, and a tympanic membrane with retraction pockets (TMRP). ET angle and length were measured using computed tomography employing the multiplanar reconstruction technique. The ETa was significantly more horizontal in diseased versus normal ears of all study groups (P = .030), and there was no group difference in ETl (P = .160). ETl was shorter in CSOM versus ITTS ears and normal ears (P = .007 and P = .003, respectively) and in cholesteatoma versus TMRP ears (P = .014). In the unilateral COM group, there were no significant differences in the ETa or ETl of diseased versus contralateral normal ears (P = .155 and P = .710, respectively). The ETa was significantly more horizontal in childhood-onset diseased versus normal ears (P = .027), and there was no group difference in ETl (P = .732). The ETa (P = .002) and ETl (P < .001) were significantly greater in males than females. A more horizontal ETa and shorter ETl could be contributory (though not significantly) etiological factors in the development of COM. 3b. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Interlimb Reflexes Induced by Electrical Stimulation of Cutaneous Nerves after Spinal Cord Injury

PubMed Central

Butler, Jane E.; Godfrey, Sharlene; Thomas, Christine K.

2016-01-01

Whether interlimb reflexes emerge only after a severe insult to the human spinal cord is controversial. Here the aim was to examine interlimb reflexes at rest in participants with chronic (>1 year) spinal cord injury (SCI, n = 17) and able-bodied control participants (n = 5). Cutaneous reflexes were evoked by delivering up to 30 trains of stimuli to either the superficial peroneal nerve on the dorsum of the foot or the radial nerve at the wrist (5 pulses, 300 Hz, approximately every 30 s). Participants were instructed to relax the test muscles prior to the delivery of the stimuli. Electromyographic activity was recorded bilaterally in proximal and distal arm and leg muscles. Superficial peroneal nerve stimulation evoked interlimb reflexes in ipsilateral and contralateral arm and contralateral leg muscles of SCI and control participants. Radial nerve stimulation evoked interlimb reflexes in the ipsilateral leg and contralateral arm muscles of control and SCI participants but only contralateral leg muscles of control participants. Interlimb reflexes evoked by superficial peroneal nerve stimulation were longer in latency and duration, and larger in magnitude in SCI participants. Interlimb reflex properties were similar for both SCI and control groups for radial nerve stimulation. Ascending interlimb reflexes tended to occur with a higher incidence in participants with SCI, while descending interlimb reflexes occurred with a higher incidence in able-bodied participants. However, the overall incidence of interlimb reflexes in SCI and neurologically intact participants was similar which suggests that the neural circuitry underlying these reflexes does not necessarily develop after central nervous system injury. PMID:27049521

A cocktail-party listening experiment with children

NASA Astrophysics Data System (ADS)

Wightman, Frederic; Callahan, Michael; Kistler, Doris

2003-04-01

In an experiment modeled after one reported recently by Brungart and Simpson [J. Acoust. Soc. Am. 112, 2985-2995 (2002)], 38 children (ages 4-16) and 10 adults responded to a monaural target speech signal in the presence of one or two distracter speech signals. The target speaker was a male and the distracter speakers were females. When two distracters were present they were in different ears. Performance at several different target ear S/N was measured and psychometric functions were fitted to estimate threshold, or the 50% performance level. The youngest children required approximately 20 dB higher S/N than adults to achieve threshold with a single distracter. This difference disappeared by age 16. The impact of adding the contralateral distracter, which is thought to contribute only informational masking, was roughly constant across age, however. Adult thresholds increased about 11 dB and the thresholds for the youngest children increased about 10 dB. This was surprising given previous experiments that showed much larger informational masking effects in young children. Also inconsistent with previous results is the lack of individual differences. Nearly all listeners showed almost the same contralateral distracter effect. [Work supported by NICHD.

Magnetic-Stimulation-Related Physiological Artifacts in Hemodynamic Near-Infrared Spectroscopy Signals

PubMed Central

Näsi, Tiina; Mäki, Hanna; Kotilahti, Kalle; Nissilä, Ilkka; Haapalahti, Petri; Ilmoniemi, Risto J.

2011-01-01

Hemodynamic responses evoked by transcranial magnetic stimulation (TMS) can be measured with near-infrared spectroscopy (NIRS). This study demonstrates that cerebral neuronal activity is not their sole contributor. We compared bilateral NIRS responses following brain stimulation to those from the shoulders evoked by shoulder stimulation and contrasted them with changes in circulatory parameters. The left primary motor cortex of ten subjects was stimulated with 8-s repetitive TMS trains at 0.5, 1, and 2 Hz at an intensity of 75% of the resting motor threshold. Hemoglobin concentration changes were measured with NIRS on the stimulated and contralateral hemispheres. The photoplethysmograph (PPG) amplitude and heart rate were recorded as well. The left shoulder of ten other subjects was stimulated with the same protocol while the hemoglobin concentration changes in both shoulders were measured. In addition to PPG amplitude and heart rate, the pulse transit time was recorded. The brain stimulation reduced the total hemoglobin concentration (HbT) on the stimulated and contralateral hemispheres. The shoulder stimulation reduced HbT on the stimulated shoulder but increased it contralaterally. The waveforms of the HbT responses on the stimulated hemisphere and shoulder correlated strongly with each other (r = 0.65–0.87). All circulatory parameters were also affected. The results suggest that the TMS-evoked NIRS signal includes components that do not result directly from cerebral neuronal activity. These components arise from local effects of TMS on the vasculature. Also global circulatory effects due to arousal may affect the responses. Thus, studies involving TMS-evoked NIRS responses should be carefully controlled for physiological artifacts and effective artifact removal methods are needed to draw inferences about TMS-evoked brain activity. PMID:21887362

Magnetic-stimulation-related physiological artifacts in hemodynamic near-infrared spectroscopy signals.

PubMed

Näsi, Tiina; Mäki, Hanna; Kotilahti, Kalle; Nissilä, Ilkka; Haapalahti, Petri; Ilmoniemi, Risto J

2011-01-01

Hemodynamic responses evoked by transcranial magnetic stimulation (TMS) can be measured with near-infrared spectroscopy (NIRS). This study demonstrates that cerebral neuronal activity is not their sole contributor. We compared bilateral NIRS responses following brain stimulation to those from the shoulders evoked by shoulder stimulation and contrasted them with changes in circulatory parameters. The left primary motor cortex of ten subjects was stimulated with 8-s repetitive TMS trains at 0.5, 1, and 2 Hz at an intensity of 75% of the resting motor threshold. Hemoglobin concentration changes were measured with NIRS on the stimulated and contralateral hemispheres. The photoplethysmograph (PPG) amplitude and heart rate were recorded as well. The left shoulder of ten other subjects was stimulated with the same protocol while the hemoglobin concentration changes in both shoulders were measured. In addition to PPG amplitude and heart rate, the pulse transit time was recorded. The brain stimulation reduced the total hemoglobin concentration (HbT) on the stimulated and contralateral hemispheres. The shoulder stimulation reduced HbT on the stimulated shoulder but increased it contralaterally. The waveforms of the HbT responses on the stimulated hemisphere and shoulder correlated strongly with each other (r = 0.65-0.87). All circulatory parameters were also affected. The results suggest that the TMS-evoked NIRS signal includes components that do not result directly from cerebral neuronal activity. These components arise from local effects of TMS on the vasculature. Also global circulatory effects due to arousal may affect the responses. Thus, studies involving TMS-evoked NIRS responses should be carefully controlled for physiological artifacts and effective artifact removal methods are needed to draw inferences about TMS-evoked brain activity.

Cooperation Not Competition: Bihemispheric tDCS and fMRI Show Role for Ipsilateral Hemisphere in Motor Learning.

PubMed

Waters, Sheena; Wiestler, Tobias; Diedrichsen, Jörn

2017-08-02

What is the role of ipsilateral motor and premotor areas in motor learning? One view is that ipsilateral activity suppresses contralateral motor cortex and, accordingly, that inhibiting ipsilateral regions can improve motor learning. Alternatively, the ipsilateral motor cortex may play an active role in the control and/or learning of unilateral hand movements. We approached this question by applying double-blind bihemispheric transcranial direct current stimulation (tDCS) over both contralateral and ipsilateral motor cortex in a between-group design during 4 d of unimanual explicit sequence training in human participants. Independently of whether the anode was placed over contralateral or ipsilateral motor cortex, bihemispheric stimulation yielded substantial performance gains relative to unihemispheric or sham stimulation. This performance advantage appeared to be supported by plastic changes in both hemispheres. First, we found that behavioral advantages generalized strongly to the untrained hand, suggesting that tDCS strengthened effector-independent representations. Second, functional imaging during speed-matched execution of trained sequences conducted 48 h after training revealed sustained, polarity-independent increases in activity in both motor cortices relative to the sham group. These results suggest a cooperative rather than competitive interaction of the two motor cortices during skill learning and suggest that bihemispheric brain stimulation during unimanual skill learning may be beneficial because it harnesses plasticity in the ipsilateral hemisphere. SIGNIFICANCE STATEMENT Many neurorehabilitation approaches are based on the idea that is beneficial to boost excitability in the contralateral hemisphere while attenuating that of the ipsilateral cortex to reduce interhemispheric inhibition. We observed that bihemispheric transcranial direct current stimulation (tDCS) with the excitatory anode either over contralateral or ipsilateral motor cortex facilitated motor learning nearly twice as strongly as unihemispheric tDCS. These increases in motor learning were accompanied by increases in fMRI activation in both motor cortices that outlasted the stimulation period, as well as increased generalization to the untrained hand. Collectively, our findings suggest a cooperative rather than a competitive role of the hemispheres and imply that it is most beneficial to harness plasticity in both hemispheres in neurorehabilitation of motor deficits. Copyright © 2017 Waters et al.

Ear reconstruction using a porous polyethylene framework and temporoparietal fascia flap.

PubMed

Reinisch, John F; Lewin, Sheryl

2009-08-01

Ear reconstruction is a difficult procedure requiring a framework and soft tissue covering. The traditional method uses a rib cartilage framework placed beneath scalp skin. This method has been used for 50 years despite inherent problems with both harvesting rib cartilage and using scalp for coverage. The authors describe a method using a porous polyethylene (PPE) framework covered by a large temporoparietal fascia (TFP) flap raised with the underlying subgaleal fascia (SGF). The entire implant is covered by the two-layered flap, which can be raised without any scalp incision. The skin grafts applied to the covered implant lie on the SGF. The trilaminar structure of the SGF allows the skin to move independently over the implant, resisting shear forces and reducing the probability of implant exposure. Ear reconstruction using the PPE framework was performed on 786 ears over an 18-year period. Initial complications were common. With improved implant design and complete coverage of the implant with both the TPF and SGF, exposure rate dropped to 7% with a 12-year follow-up. Implant fractures decreased to less than 3%. The PPE/TPF method allows earlier ear reconstruction in children with minimal scarring and discomfort. The reconstructed ear can closely mimic the shape and projection of the natural contralateral ear in fewer stages and with a shorter learning curve. Copyright Thieme Medical Publishers.

Reliability of measures of transient evoked otoacoustic emissions with contralateral suppression.

PubMed

Stuart, Andrew; Cobb, Kensi M

2015-01-01

The reliability of measures of transient evoked otoacoustic emissions (TEOAEs) with contralateral suppression was examined. The effect of test session (i.e., initial test; retest without probe removal; retest with probe removal; and retest 1-2 days post initial test), gender, and ear was examined in 14 young adult females and 14 young adult males. TEOAEs were obtained bilaterally with 60 dB peSPL linear click stimuli with and without a contralateral 65 dB SPL broadband noise suppressor. Absolute TEOAE suppression and a normalized index of TEOAE suppression (i.e., percentage of suppression) were examined. Reliability of these measures was assessed with repeated measures linear mixed model analysis of variance, a coefficient of reliability, and Bland-Altman analyses. There were no statistically significant (p>0.05) main effects of test, gender, and ear or interactions for both absolute dB and % TEOAE suppression values. Cronbach's α were greater than 0.90 across the four tests for both TEOAE measures. Mean test differences or bias (i.e., between the initial and subsequent tests) for absolute and % TEOAE suppression ranged from -0.05 to 0.11 dB and -1.5% to 1.1%, respectively. There was no proportional/systematic bias with the mean differences of the first and subsequent measurements. Data herein were consistent with the view that bilateral TEOAE suppression measures are reliable across test sessions of 1-2 days among females and males and may provide a method to monitor medial olivocochlear efferent reflex status over time. Copyright © 2015 Elsevier Inc. All rights reserved.

The medial olivocochlear reflex in children during active listening.

PubMed

Smith, Spencer B; Cone, Barbara

2015-08-01

To determine if active listening modulates the strength of the medial olivocochlear (MOC) reflex in children. Click-evoked otoacoustic emissions (CEOAEs) were recorded from the right ear in quiet and in four test conditions: one with contralateral broadband noise (BBN) only, and three with active listening tasks wherein attention was directed to speech embedded in contralateral BBN. Fifteen typically-developing children (ranging in age from 8 to14 years) with normal hearing. CEOAE levels were reduced in every condition with contralateral acoustic stimulus (CAS) when compared to preceding quiet conditions. There was an additional systematic decrease in CEOAE level with increased listening task difficulty, although this effect was very small. These CEOAE level differences were most apparent in the 8-18 ms region after click onset. Active listening may change the strength of the MOC reflex in children, although the effects reported here are very subtle. Further studies are needed to verify that task difficulty modulates the activity of the MOC reflex in children.

The medial olivocochlear reflex in children during active listening

PubMed Central

Smith, Spencer B.; Cone, Barbara

2015-01-01

Objective To determine if active listening modulates the strength of the medial olivocochlear (MOC) reflex in children. Design Click-evoked otoacoustic emissions (CEOAEs) were recorded from the right ear in quiet and in four test conditions: one with contralateral broadband noise (BBN) only, and three with active listening tasks wherein attention was directed to speech embedded in contralateral BBN. Study sample Fifteen typically-developing children (ranging in age from 8 to 14 years) with normal hearing. Results CEOAE levels were reduced in every condition with contralateral acoustic stimulus (CAS) when compared to preceding quiet conditions. There was an additional systematic decrease in CEOAE level with increased listening task difficulty, although this effect was very small. These CEOAE level differences were most apparent in the 8–18 ms region after click onset. Conclusions Active listening may change the strength of the MOC reflex in children, although the effects reported here are very subtle. Further studies are needed to verify that task difficulty modulates the activity of the MOC reflex in children. PMID:25735203

Short-duration stimulation of the supplementary eye fields perturbs anti-saccade performance while potentiating contralateral head orienting.

PubMed

Chapman, Brendan B; Corneil, Brian D

2014-01-01

Many forms of brain stimulation utilize the notion of state dependency, whereby greater influences are observed when a given area is more engaged at the time of stimulation. Here, by delivering intracortical microstimulation (ICMS) to the supplementary eye fields (SEF) of monkeys performing interleaved pro- and anti-saccades, we show a surprising diversity of state-dependent effects of ICMS-SEF. Short-duration ICMS-SEF passed around cue presentation selectively disrupted anti-saccades by increasing reaction times and error rates bilaterally, and also recruited neck muscles, favoring contralateral head turning to a greater degree on anti-saccade trials. These results are consistent with the functional relevance of the SEF for anti-saccades. The multiplicity of stimulation-evoked effects, with ICMS-SEF simultaneously disrupting anti-saccade performance and facilitating contralateral head orienting, probably reflects both the diversity of cortical and subcortical targets of SEF projections, and the response of this oculomotor network to stimulation. We speculate that the bilateral disruption of anti-saccades arises via feedback loops that may include the thalamus, whereas neck muscle recruitment arises via feedforward polysynaptic pathways to the motor periphery. Consideration of both sets of results reveals a more complete picture of the highly complex and multiphasic response to ICMS-SEF that can play out differently in different effector systems.

A Fully-Implantable Cochlear Implant SoC with Piezoelectric Middle-Ear Sensor and Arbitrary Waveform Neural Stimulation.

PubMed

Yip, Marcus; Jin, Rui; Nakajima, Hideko Heidi; Stankovic, Konstantina M; Chandrakasan, Anantha P

2015-01-01

A system-on-chip for an invisible, fully-implantable cochlear implant is presented. Implantable acoustic sensing is achieved by interfacing the SoC to a piezoelectric sensor that detects the sound-induced motion of the middle ear. Measurements from human cadaveric ears demonstrate that the sensor can detect sounds between 40 and 90 dB SPL over the speech bandwidth. A highly-reconfigurable digital sound processor enables system power scalability by reconfiguring the number of channels, and provides programmable features to enable a patient-specific fit. A mixed-signal arbitrary waveform neural stimulator enables energy-optimal stimulation pulses to be delivered to the auditory nerve. The energy-optimal waveform is validated with in-vivo measurements from four human subjects which show a 15% to 35% energy saving over the conventional rectangular waveform. Prototyped in a 0.18 μ m high-voltage CMOS technology, the SoC in 8-channel mode consumes 572 μ W of power including stimulation. The SoC integrates implantable acoustic sensing, sound processing, and neural stimulation on one chip to minimize the implant size, and proof-of-concept is demonstrated with measurements from a human cadaver ear.

Auditory Temporal Processing Deficits in Chronic Stroke: A Comparison of Brain Damage Lateralization Effect.

PubMed

Jafari, Zahra; Esmaili, Mahdiye; Delbari, Ahmad; Mehrpour, Masoud; Mohajerani, Majid H

2016-06-01

There have been a few reports about the effects of chronic stroke on auditory temporal processing abilities and no reports regarding the effects of brain damage lateralization on these abilities. Our study was performed on 2 groups of chronic stroke patients to compare the effects of hemispheric lateralization of brain damage and of age on auditory temporal processing. Seventy persons with normal hearing, including 25 normal controls, 25 stroke patients with damage to the right brain, and 20 stroke patients with damage to the left brain, without aphasia and with an age range of 31-71 years were studied. A gap-in-noise (GIN) test and a duration pattern test (DPT) were conducted for each participant. Significant differences were found between the 3 groups for GIN threshold, overall GIN percent score, and DPT percent score in both ears (P ≤ .001). For all stroke patients, performance in both GIN and DPT was poorer in the ear contralateral to the damaged hemisphere, which was significant in DPT and in 2 measures of GIN (P ≤ .046). Advanced age had a negative relationship with temporal processing abilities for all 3 groups. In cases of confirmed left- or right-side stroke involving auditory cerebrum damage, poorer auditory temporal processing is associated with the ear contralateral to the damaged cerebral hemisphere. Replication of our results and the use of GIN and DPT tests for the early diagnosis of auditory processing deficits and for monitoring the effects of aural rehabilitation interventions are recommended. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Gustatory otalgia and wet ear syndrome: a possible cross-innervation after ear surgery.

PubMed

Saito, H

1999-04-01

The chorda tympani and Arnold's nerves have close approximation to each other and their cross-innervation is possible after ear surgery. A retrospective study was performed with a temporal bone pathology case and two clinical cases as representatives of such a possibility. Patients had severe otalgia and wet ear during gustatory stimulation. A temporal bone pathology case was studied under a light microscope. Earache and/or wet ear were provoked during gustatory stimulation. Wet ear was tested with iodine-starch reaction after the subject tasted lemon juice. The temporal bone specimen has clusters of regenerated fibers in the tympanic cavity in the area of the chorda tympani and Arnold's nerves, suggesting a possibility of mixing. There are regenerated fibers in the iter chordae anterius, showing successful bridging of the chorda tympani nerves across a long gap. Detachment of the skin over the operated mastoid bowl obscured signs in one clinical case. Another clinical case of gustatory wet ear showed objective evidence of cross-innervation with iodine-starch reaction. The detachment procedure and iodine-starch reaction were the proofs that the signs were related to regenerated fibers. This is the first report of gustatory otalgia and wet ear after ear surgery.

[A physiological investigation of chronic electrical stimulation with scala tympani electrodes in kittens].

PubMed

Ni, D

1992-12-01

A physiological investigation of cochlear electrical stimulation was undertaken in six two-month-old kittens. The scala tympani electrodes were implanted and electrically stimulated using biphasic balanced electrical pulses for periods of 1000-1500h in four ears. Four ears received implants for same period but without electrical stimulation. The other two ears served as normal control. The results indicated: 1) Chronic electrical stimulation of the cochlea within electrochemically safe limits did not influence the hearing of kittens and the normal delivery of impulses evoked by acoustic and electrical signals on the auditory brainstem pathway. 2) The wave shapes of EABRs were similar to those of ABRs. The amplitudes of EABRs showed a significant increase following chronic electrical stimulation, resulting in a leftward shift in the input/output function. The absolute latencies and interwave latencies of waves II-III, III-IV and II-IV were significantly shorter than those of ABRs. These results imply that there was no adverse effect of chronic electrical stimulation on the maturing auditory systems of kittens using these electrical parameters and the mechanism of electrical hearing should be further studied.

Simultaneous measurement of noise-activated middle-ear muscle reflex and stimulus frequency otoacoustic emissions.

PubMed

Goodman, Shawn S; Keefe, Douglas H

2006-06-01

Otoacoustic emissions serve as a noninvasive probe of the medial olivocochlear (MOC) reflex. Stimulus frequency otoacoustic emissions (SFOAEs) elicited by a low-level probe tone may be the optimal type of emission for studying MOC effects because at low levels, the probe itself does not elicit the MOC reflex [Guinan et al. (2003) J. Assoc. Res. Otolaryngol. 4:521]. Based on anatomical considerations, the MOC reflex activated by ipsilateral acoustic stimulation (mediated by the crossed olivocochlear bundle) is predicted to be stronger than the reflex to contralateral stimulation. Broadband noise is an effective activator of the MOC reflex; however, it is also an effective activator of the middle-ear muscle (MEM) reflex, which can make results difficult to interpret. The MEM reflex may be activated at lower levels than measured clinically, and most previous human studies have not explicitly included measurements to rule out MEM reflex contamination. The current study addressed these issues using a higher-frequency SFOAE probe tone to test for cochlear changes mediated by the MOC reflex, while simultaneously monitoring the MEM reflex using a low-frequency probe tone. Broadband notched noise was presented ipsilaterally at various levels to elicit probe-tone shifts. Measurements are reported for 15 normal-hearing subjects. With the higher-frequency probe near 1.5 kHz, only 20% of subjects showed shifts consistent with an MOC reflex in the absence of an MEM-induced shift. With the higher-frequency probe near 3.5 kHz, up to 40% of subjects showed shifts in the absence of an MEM-induced shift. However, these responses had longer time courses than expected for MOC-induced shifts, and may have been dominated by other cochlear processes, rather than MOC reflex. These results suggest caution in the interpretation of effects observed using ipsilaterally presented acoustic activators intended to excite the MOC reflex.

[Transcranial magnetic stimulation and motor cortex stimulation in neuropathic pain].

PubMed

Mylius, V; Ayache, S S; Teepker, M; Kappus, C; Kolodziej, M; Rosenow, F; Nimsky, C; Oertel, W H; Lefaucheur, J P

2012-12-01

Non-invasive and invasive cortical stimulation allows the modulation of therapy-refractory neuropathic pain. High-frequency repetitive transcranial magnetic stimulation (rTMS) of the contralateral motor cortex yields therapeutic effects at short-term and predicts the benefits of epidural motor cortex stimulation (MCS). The present article summarizes the findings on application, mechanisms and therapeutic effects of cortical stimulation in neuropathic pain.

Effective Connectivity Reveals Right-Hemisphere Dominance in Audiospatial Perception: Implications for Models of Spatial Neglect

PubMed Central

Friston, Karl J.; Mattingley, Jason B.; Roepstorff, Andreas; Garrido, Marta I.

2014-01-01

Detecting the location of salient sounds in the environment rests on the brain's ability to use differences in sounds arriving at both ears. Functional neuroimaging studies in humans indicate that the left and right auditory hemispaces are coded asymmetrically, with a rightward attentional bias that reflects spatial attention in vision. Neuropsychological observations in patients with spatial neglect have led to the formulation of two competing models: the orientation bias and right-hemisphere dominance models. The orientation bias model posits a symmetrical mapping between one side of the sensorium and the contralateral hemisphere, with mutual inhibition of the ipsilateral hemisphere. The right-hemisphere dominance model introduces a functional asymmetry in the brain's coding of space: the left hemisphere represents the right side, whereas the right hemisphere represents both sides of the sensorium. We used Dynamic Causal Modeling of effective connectivity and Bayesian model comparison to adjudicate between these alternative network architectures, based on human electroencephalographic data acquired during an auditory location oddball paradigm. Our results support a hemispheric asymmetry in a frontoparietal network that conforms to the right-hemisphere dominance model. We show that, within this frontoparietal network, forward connectivity increases selectively in the hemisphere contralateral to the side of sensory stimulation. We interpret this finding in light of hierarchical predictive coding as a selective increase in attentional gain, which is mediated by feedforward connections that carry precision-weighted prediction errors during perceptual inference. This finding supports the disconnection hypothesis of unilateral neglect and has implications for theories of its etiology. PMID:24695717

Speech perception with combined electric-acoustic stimulation and bilateral cochlear implants in a multisource noise field.

PubMed

Rader, Tobias; Fastl, Hugo; Baumann, Uwe

2013-01-01

The aim of the study was to measure and compare speech perception in users of electric-acoustic stimulation (EAS) supported by a hearing aid in the unimplanted ear and in bilateral cochlear implant (CI) users under different noise and sound field conditions. Gap listening was assessed by comparing performance in unmodulated and modulated Comité Consultatif International Téléphonique et Télégraphique (CCITT) noise conditions, and binaural interaction was investigated by comparing single source and multisource sound fields. Speech perception in noise was measured using a closed-set sentence test (Oldenburg Sentence Test, OLSA) in a multisource noise field (MSNF) consisting of a four-loudspeaker array with independent noise sources and a single source in frontal position (S0N0). Speech simulating noise (Fastl-noise), CCITT-noise (continuous), and OLSA-noise (pseudo continuous) served as noise sources with different temporal patterns. Speech tests were performed in two groups of subjects who were using either EAS (n = 12) or bilateral CIs (n = 10). All subjects in the EAS group were fitted with a high-power hearing aid in the opposite ear (bimodal EAS). The average group score on monosyllable in quiet was 68.8% (EAS) and 80.5% (bilateral CI). A group of 22 listeners with normal hearing served as controls to compare and evaluate potential gap listening effects in implanted patients. Average speech reception thresholds in the EAS group were significantly lower than those for the bilateral CI group in all test conditions (CCITT 6.1 dB, p = 0.001; Fastl-noise 5.4 dB, p < 0.01; Oldenburg-(OL)-noise 1.6 dB, p < 0.05). Bilateral CI and EAS user groups showed a significant improvement of 4.3 dB (p = 0.004) and 5.4 dB (p = 0.002) between S0N0 and MSNF sound field conditions respectively, which signifies advantages caused by bilateral interaction in both groups. Performance in the control group showed a significant gap listening effect with a difference of 6.5 dB between modulated and unmodulated noise in S0N0, and a difference of 3.0 dB in MSNF. The ability to "glimpse" into short temporal masker gaps was absent in both groups of implanted subjects. Combined EAS in one ear supported by a hearing aid on the contralateral ear provided significantly improved speech perception compared with bilateral cochlear implantation. Although the scores for monosyllable words in quiet were higher in the bilateral CI group, the EAS group performed better in different noise and sound field conditions. Furthermore, the results indicated that binaural interaction between EAS in one ear and residual acoustic hearing in the opposite ear enhances speech perception in complex noise situations. Both bilateral CI and bimodal EAS users did not benefit from short temporal masker gaps, therefore the better performance of the EAS group in modulated noise conditions could be explained by the improved transmission of fundamental frequency cues in the lower-frequency region of acoustic hearing, which might foster the grouping of auditory objects.

Striatal somatotopy and motor responses evoked by acute electrical stimulation of the posterior striatum in rats.

PubMed

Vilela-Filho, Osvaldo; Barros, Breno A; Arruda, Mariana M; Castro, Thaisa S; Souza, Joaquim T; Silva, Delson J; Ferraz, Fernando P; Ragazzo, Paulo C

2014-02-01

Previous experiments suggest that the striatal sensorimotor territory in rats is located in its dorsolateral region, along the rostrocaudal axis, unlike what has been observed in primates. In the present study, electrical stimulation was performed to investigate the degree of participation of the posterior striatum in its motor territory, its somatotopic organization, and the motor responses evoked by stimulation. Twenty-five rats were submitted to stereotactic stimulation of the posterior striatum under general anesthesia, receiving consecutively four different current intensities. The motor responses observed in the different body parts were registered for later comparison. We considered as threshold the smallest of these current intensities able to evoke a motor response. The observed motor responses were qualitatively different for each segment: forepaws: ipsilateral, adduction, and contralateral abduction; hindpaws: ipsilateral, flexion, and contralateral, extension/abduction; trunk, rotation/flexion; and tail, rotation/elevation. High-frequency, small-amplitude distal tremor occurred in the ipsilateral forepaw in 95% of the animals. Progressively larger current intensities were necessary for the induction of motor response in the forepaws, hindpaws, and trunk/tail, in that order. The results allowed us to infer the following posterior striatal somatotopic organization: forepaws, posterolaterally, being the contralateral medial to the ipsilateral; trunk/tail, anteromedially; and hindpaws, in an intermediate position, being the contralateral posterior to the ipsilateral. It is suggested that the tremor and the other observed motor responses derive from the excitation of striatal projection neurons and that the striatum may play an important role in the genesis of essential tremor. © 2013 International Neuromodulation Society.

Increased contralateral suppression of otoacoustic emissions indicates a hyperresponsive medial olivocochlear system in humans with tinnitus and hyperacusis

PubMed Central

Shera, Christopher A.; Melcher, Jennifer R.

2014-01-01

Atypical medial olivocochlear (MOC) feedback from brain stem to cochlea has been proposed to play a role in tinnitus, but even well-constructed tests of this idea have yielded inconsistent results. In the present study, it was hypothesized that low sound tolerance (mild to moderate hyperacusis), which can accompany tinnitus or occur on its own, might contribute to the inconsistency. Sound-level tolerance (SLT) was assessed in subjects (all men) with clinically normal or near-normal thresholds to form threshold-, age-, and sex-matched groups: 1) no tinnitus/high SLT, 2) no tinnitus/low SLT, 3) tinnitus/high SLT, and 4) tinnitus/low SLT. MOC function was measured from the ear canal as the change in magnitude of distortion-product otoacoustic emissions (DPOAE) elicited by broadband noise presented to the contralateral ear. The noise reduced DPOAE magnitude in all groups (“contralateral suppression”), but significantly more reduction occurred in groups with tinnitus and/or low SLT, indicating hyperresponsiveness of the MOC system compared with the group with no tinnitus/high SLT. The results suggest hyperresponsiveness of the interneurons of the MOC system residing in the cochlear nucleus and/or MOC neurons themselves. The present data, combined with previous human and animal data, indicate that neural pathways involving every major division of the cochlear nucleus manifest hyperactivity and/or hyperresponsiveness in tinnitus and/or low SLT. The overactivation may develop in each pathway separately. However, a more parsimonious hypothesis is that top-down neuromodulation is the driving force behind ubiquitous overactivation of the auditory brain stem and may correspond to attentional spotlighting on the auditory domain in tinnitus and hyperacusis. PMID:25231612

Functional and structural aspects of tinnitus-related enhancement and suppression of auditory cortex activity.

PubMed

Diesch, Eugen; Andermann, Martin; Flor, Herta; Rupp, Andre

2010-05-01

The steady-state auditory evoked magnetic field was recorded in tinnitus patients and controls, both either musicians or non-musicians, all of them with high-frequency hearing loss. Stimuli were AM-tones with two modulation frequencies and three carrier frequencies matching the "audiometric edge", i.e. the frequency above which hearing loss increases more rapidly, the tinnitus frequency or the frequency 1 1/2 octaves above the audiometric edge in controls, and a frequency 1 1/2 octaves below the audiometric edge. Stimuli equated in carrier frequency, but differing in modulation frequency, were simultaneously presented to the two ears. The modulation frequency-specific components of the dual steady-state response were recovered by bandpass filtering. In both hemispheres, the source amplitude of the response was larger for contralateral than ipsilateral input. In non-musicians with tinnitus, this laterality effect was enhanced in the hemisphere contralateral and reduced in the hemisphere ipsilateral to the tinnitus ear, especially for the tinnitus frequency. The hemisphere-by-input laterality dominance effect was smaller in musicians than in non-musicians. In both patient groups, source amplitude change over time, i.e. amplitude slope, was increasing with tonal frequency for contralateral input and decreasing for ipsilateral input. However, slope was smaller for musicians than non-musicians. In patients, source amplitude was negatively correlated with the MRI-determined volume of the medial partition of Heschl's gyrus. Tinnitus patients show an altered excitatory-inhibitory balance reflecting the downregulation of inhibition and resulting in a steeper dominance hierarchy among simultaneous processes in auditory cortex. Direction and extent of this alteration are modulated by musicality and auditory cortex volume. 2010 Elsevier Inc. All rights reserved.

Combined Electric and Contralateral Acoustic Hearing: Word and Sentence Recognition with Bimodal Hearing

ERIC Educational Resources Information Center

Gifford, Rene H.; Dorman, Michael F.; McKarns, Sharon A.; Spahr, Anthony J.

2007-01-01

Purpose: The authors assessed whether (a) a full-insertion cochlear implant would provide a higher level of speech understanding than bilateral low-frequency acoustic hearing, (b) contralateral acoustic hearing would add to the speech understanding provided by the implant, and (c) the level of performance achieved with electric stimulation plus…

Dynamics of the contralateral white noise-induced enhancement in the guinea pig's middle latency response.

PubMed

Goksoy, Cuneyt; Demirtas, Serdar; Ungan, Pekcan

2004-08-13

The peak-to-peak amplitude of temporal middle latency response (MLR) of the guinea pig, evoked by a click in the contralateral ear, according to the recording side, is increased with the presence of continuous white noise (CWN) in the ipsilateral ear and this specialty is defined as the white noise enhancement (WNE). This phenomenon is evaluated as an interesting electrophysiological finding from the viewpoint of binaural interaction and in this study, its dynamic specifications were investigated. After the beginning of ipsilateral CWN, significant WNE was observed at 275th ms and it reached to a maximum, with an increase more than 40%, at 350th ms. After a habituation occurred, WNE reached to 20% on the 4th second by gradually decreasing and came to a steady state. In the time window between 2 and 5 ms after CWN started, a surprising amplitude decrease is observed. Therefore, CWN causes an effect, like a click, in the short-term and this on-response type effect originates from low level binaural centers, which decreases the MLR amplitude. However, the same CWN increases the MLR amplitude (WNE) by the effects over the high level binaural centers in the succeeding period, by its continuous characteristic.

The Tympanic Membrane Motion in Forward and Reverse Middle-Ear Sound Transmission

NASA Astrophysics Data System (ADS)

Cheng, Jeffrey Tao; Harrington, Ellery; Horwitz, Rachelle; Furlong, Cosme; Rosowski, John J.

2011-11-01

Sound-induced displacement of the tympanic membrane (TM) is the first stage in the forward transformation of environmental sound to sound within the inner ear, while displacement of the TM induced by mechanical motions of the ossicular chain is the last stage in the reverse transformation of sound generated within the inner ear to clinically valuable otoacoustic emissions (OAEs). In this study, we use stroboscopic holographic interferometry to study motions of the human cadaveric TM evoked by both forward and reverse stimuli. During forward acoustic stimulation, pure tones from 500 to 10000 Hz are used to stimulate the TM, while reverse stimulation is produced by direct mechanical stimulation of the ossicular chain. The TM surface motions in response to both forward and reverse stimuli show differences and similarities, including the modal motion patterns at specific frequencies as well as the presence and directions of traveling waves on the TM surface.

Self-demodulation of amplitude-modulated signal components in amplitude-modulated bone-conducted ultrasonic hearing

NASA Astrophysics Data System (ADS)

Ito, Kazuhito; Nakagawa, Seiji

2015-07-01

A novel hearing aid system utilizing amplitude-modulated bone-conducted ultrasound (AM-BCU) is being developed for use by profoundly deaf people. However, there is a lack of research on the acoustic aspects of AM-BCU hearing. In this study, acoustic fields in the ear canal under AM-BCU stimulation were examined with respect to the self-demodulation effect of amplitude-modulated signal components generated in the ear canal. We found self-demodulated signals with an audible sound pressure level related to the amplitude-modulated signal components of bone-conducted ultrasonic stimulation. In addition, the increases in the self-demodulated signal levels at low frequencies in the ear canal after occluding the ear canal opening, i.e., the positive occlusion effect, indicate the existence of a pathway by which the self-demodulated signals pass through the aural cartilage and soft tissue, and radiate into the ear canal.

Effect of auricular pellet acupressure on antioxidative systems in high-risk diabetes mellitus.

PubMed

Liu, Chi-Feng; Yu, Lee-Fen; Lin, Chia-Hsien; Lin, Song-Chow

2008-04-01

Free radicals and lipid peroxides, both of which are easily formed in the diabetic state, play an important role in the development of diabetic complications. Antioxidative therapy may help prevent diabetic complications caused by lipoperoxidation and free-radical formation in diabetes mellitus (DM). A number of findings suggest that oxidative stress exists in persons with high-risk DM. Auricular pellet acupressure has reportedly been an effective treatment method for a variety of medical conditions, including anxiety, juvenile myopia, essential hypertension, and senile vascular dementia. However, its effects on antioxidative enzymes have not been elucidated. We therefore evaluated the impact of auricular pellet acupressure on antioxidative status in persons with high-risk DM. Our study involved 69 persons with high-risk DM, who were allocated either to undergo acupressure as active treatment for the experimental group or to a control group. The experimental group in the study received auricular pellet acupressure three times daily for 5 consecutive days. After a 2-day rest period, the procedure was performed on the contralateral ear. Acupressure was performed twice on each ear, with each application followed by its application to the contralateral ear, over a total treatment period of 20 days. The control groups did not undergo auricular pellet acupressure. At the end of the 20-day period of treatment of the experimental group, blood was collected from all of the study participants for assay of serum superoxide dismutase (SOD) and catalase concentrations, as was also done for the control group. Serum concentrations of SOD (p < 0.05) and catalase (p < 0.0001) were significantly higher in the experimental group than in the control group. Our findings suggest that auricular pellet acupressure can increase the concentration of antioxidative enzymes in persons with high-risk DM.

Improved Auditory Nerve Survival with Nanoengineered Supraparticles for Neurotrophin Delivery into the Deafened Cochlea

PubMed Central

Tan, Justin; Wang, Yajun; Caruso, Frank; Shepherd, Robert K.

2016-01-01

Cochlear implants electrically stimulate spiral ganglion neurons (SGNs) in order to provide speech cues to severe-profoundly deaf patients. In normal hearing cochleae the SGNs depend on endogenous neurotrophins secreted by sensory cells in the organ of Corti for survival. SGNs gradually degenerate following deafness and consequently there is considerable interest in developing clinically relevant strategies to provide exogenous neurotrophins to preserve SGN survival. The present study investigated the safety and efficacy of a drug delivery system for the cochlea using nanoengineered silica supraparticles. In the present study we delivered Brain-derived neurotrophic factor (BDNF) over a period of four weeks and evaluated SGN survival as a measure of efficacy. Supraparticles were bilaterally implanted into the basal turn of cochleae in profoundly deafened guinea pigs. One ear received BDNF-loaded supraparticles and the other ear control (unloaded) supraparticles. After one month of treatment the cochleae were examined histologically. There was significantly greater survival of SGNs in cochleae that received BDNF supraparticles compared to the contralateral control cochleae (repeated measures ANOVA, p = 0.009). SGN survival was observed over a wide extent of the cochlea. The supraparticles were well tolerated within the cochlea with a tissue response that was localised to the site of implantation in the cochlear base. Although mild, the tissue response was significantly greater in cochleae treated with BDNF supraparticles compared to the controls (repeated measures ANOVA, p = 0.003). These data support the clinical potential of this technology particularly as the supraparticles can be loaded with a variety of therapeutic drugs. PMID:27788219

Evaluation of focused multipolar stimulation for cochlear implants: a preclinical safety study

NASA Astrophysics Data System (ADS)

Shepherd, Robert K.; Wise, Andrew K.; Enke, Ya Lang; Carter, Paul M.; Fallon, James B.

2017-08-01

Objective. Cochlear implants (CIs) have a limited number of independent stimulation channels due to the highly conductive nature of the fluid-filled cochlea. Attempts to develop highly focused stimulation to improve speech perception in CI users includes the use of simultaneous stimulation via multiple current sources. Focused multipolar (FMP) stimulation is an example of this approach and has been shown to reduce interaction between stimulating channels. However, compared with conventional biphasic current pulses generated from a single current source, FMP is a complex stimulus that includes extended periods of stimulation before charge recovery is achieved, raising questions on whether chronic stimulation with this strategy is safe. The present study evaluated the long-term safety of intracochlear stimulation using FMP in a preclinical animal model of profound deafness. Approach. Six cats were bilaterally implanted with scala tympani electrode arrays two months after deafening, and received continuous unilateral FMP stimulation at levels that evoked a behavioural response for periods of up to 182 d. Electrode impedance, electrically-evoked compound action potentials (ECAPs) and auditory brainstem responses (EABRs) were monitored periodically over the course of the stimulation program from both the stimulated and contralateral control cochleae. On completion of the stimulation program cochleae were examined histologically and the electrode arrays were evaluated for evidence of platinum (Pt) corrosion. Main results. There was no significant difference in electrode impedance between control and chronically stimulated electrodes following long-term FMP stimulation. Moreover, there was no significant difference between ECAP and EABR thresholds evoked from control or stimulated cochleae at either the onset of stimulation or at completion of the stimulation program. Chronic FMP stimulation had no effect on spiral ganglion neuron (SGN) survival when compared with unstimulated control cochleae. Long-term implantation typically evoked a mild foreign body reaction proximal to the electrode array; however stimulated cochleae exhibited a small but statistically significant increase in the tissue response. Finally, there was no evidence of Pt corrosion following long-term FMP stimulation; stimulated electrodes exhibited the same surface features as the unstimulated control electrodes. Significance. Chronic intracochlear FMP stimulation at levels used in the present study did not adversely affect electrically-evoked neural thresholds or SGN survival but evoked a small, benign increase in inflammatory response compared to control ears. Moreover chronic FMP stimulation does not affect the surface of Pt electrodes at suprathreshold stimulus levels. These findings support the safe clinical application of an FMP stimulation strategy.

Sound-by-sound thalamic stimulation modulates midbrain auditory excitability and relative binaural sensitivity in frogs

PubMed Central

Ponnath, Abhilash; Farris, Hamilton E.

2014-01-01

Descending circuitry can modulate auditory processing, biasing sensitivity to particular stimulus parameters and locations. Using awake in vivo single unit recordings, this study tested whether electrical stimulation of the thalamus modulates auditory excitability and relative binaural sensitivity in neurons of the amphibian midbrain. In addition, by using electrical stimuli that were either longer than the acoustic stimuli (i.e., seconds) or presented on a sound-by-sound basis (ms), experiments addressed whether the form of modulation depended on the temporal structure of the electrical stimulus. Following long duration electrical stimulation (3–10 s of 20 Hz square pulses), excitability (spikes/acoustic stimulus) to free-field noise stimuli decreased by 32%, but returned over 600 s. In contrast, sound-by-sound electrical stimulation using a single 2 ms duration electrical pulse 25 ms before each noise stimulus caused faster and varied forms of modulation: modulation lasted <2 s and, in different cells, excitability either decreased, increased or shifted in latency. Within cells, the modulatory effect of sound-by-sound electrical stimulation varied between different acoustic stimuli, including for different male calls, suggesting modulation is specific to certain stimulus attributes. For binaural units, modulation depended on the ear of input, as sound-by-sound electrical stimulation preceding dichotic acoustic stimulation caused asymmetric modulatory effects: sensitivity shifted for sounds at only one ear, or by different relative amounts for both ears. This caused a change in the relative difference in binaural sensitivity. Thus, sound-by-sound electrical stimulation revealed fast and ear-specific (i.e., lateralized) auditory modulation that is potentially suited to shifts in auditory attention during sound segregation in the auditory scene. PMID:25120437

Sound-by-sound thalamic stimulation modulates midbrain auditory excitability and relative binaural sensitivity in frogs.

PubMed

Ponnath, Abhilash; Farris, Hamilton E

2014-01-01

Descending circuitry can modulate auditory processing, biasing sensitivity to particular stimulus parameters and locations. Using awake in vivo single unit recordings, this study tested whether electrical stimulation of the thalamus modulates auditory excitability and relative binaural sensitivity in neurons of the amphibian midbrain. In addition, by using electrical stimuli that were either longer than the acoustic stimuli (i.e., seconds) or presented on a sound-by-sound basis (ms), experiments addressed whether the form of modulation depended on the temporal structure of the electrical stimulus. Following long duration electrical stimulation (3-10 s of 20 Hz square pulses), excitability (spikes/acoustic stimulus) to free-field noise stimuli decreased by 32%, but returned over 600 s. In contrast, sound-by-sound electrical stimulation using a single 2 ms duration electrical pulse 25 ms before each noise stimulus caused faster and varied forms of modulation: modulation lasted <2 s and, in different cells, excitability either decreased, increased or shifted in latency. Within cells, the modulatory effect of sound-by-sound electrical stimulation varied between different acoustic stimuli, including for different male calls, suggesting modulation is specific to certain stimulus attributes. For binaural units, modulation depended on the ear of input, as sound-by-sound electrical stimulation preceding dichotic acoustic stimulation caused asymmetric modulatory effects: sensitivity shifted for sounds at only one ear, or by different relative amounts for both ears. This caused a change in the relative difference in binaural sensitivity. Thus, sound-by-sound electrical stimulation revealed fast and ear-specific (i.e., lateralized) auditory modulation that is potentially suited to shifts in auditory attention during sound segregation in the auditory scene.

A Case Report on Red Ear Syndrome with Tinnitus Successfully Treated with Transcranial Random Noise Stimulation.

PubMed

Kreuzer, Peter M; Vielsmeier, Veronika; Poeppl, Timm B; Langguth, Berthold

2017-01-01

The red ear syndrome represents a rare symptom complex consisting of auricular erythema associated with painful and burning sensations. It has been described in combination with tinnitus rarely. It has been hypothesized to be etiologically related to altered trigeminal afferent input, temporomandibular disorders, and thalamic dysfunction. The initial objective of applying transcranial random noise stimulation (tRNS) in a case of red ear syndrome in combination with tinnitus was the alleviation of the phantom sounds. This is a case report on the successful treatment of red ear syndrome with tinnitus by means of transcranial random noise stimulation (tRNS) and a short review on the published cases of this condition. We present the case of a 50-year-old woman reporting a simultaneous onset of constant left-sided tinnitus and feelings of warmth accompanied by an intermittent stabbing and/or oppressive pain stretching from the ipsilateral ear to the head/neck/shoulder region, occasionally accompanied by nausea/vomiting and dizziness. After failure of pharmacological treatment attempts, either because of lacking clinical effects (gabapentin, zolmitriptan, and indomethacin) or because of adverse reactions (pregabaline), the patient was offered an experimental neuromodulatory treatment with bitemporal tRNS primarily targeting the tinnitus complaints of the patient. tRNS was conducted in 2 - 3 day sessions (stimulation site: bilateral temporal cortex/2.0 mA/10 s on-and-off-ramp/offset 0 mA/20 min/random frequencies 101 - 640 Hz / NeuroConn Eldith DC-Stimulator plus). In 3 consecutive pain attacks repeated sessions of tRNS resulted in substantial alleviation of pain intensity and a prolongation of the interval between attacks. This was an expected finding as the proposed tRNS treatment was initially offered to the patient aiming at an alleviation of the tinnitus complaints (which remained unaffected by tRNS). The reported data derive from compassionate use treatment in one single patient. Application of a sham condition would have been desirable, but is not possible in the context of compassionate use treatment. Nevertheless, we would consider it rather unlikely that the reported effects are purely unspecific as the patient did exclusively report symptom alleviation of pain-related parameters without affecting the tinnitus. This case report demonstrates the feasibility and therapeutic potential of applying neuromodulatory treatment approaches in red ear syndrome, a rare form of trigemino-autonomal headache. Therefore, it deserves detailed observation in clinical routine applications as well as controlled trials further investigating its neurobiological effects. Key words: Red ear syndrome, pain, trigemino-autonomal headache, chronic tinnitus, transcranial electrical stimulation, random noise stimulation.

Aural symptoms in patients with temporomandibular joint disorders: multiple frequency tympanometry provides objective evidence of changes in middle ear impedance.

PubMed

Riga, Maria; Xenellis, John; Peraki, Eleni; Ferekidou, Elisa; Korres, Stavros

2010-12-01

The association of temporomandibular joint (TMJ) disorders with aural symptoms, such as tinnitus, otic fullness, and subjective decrease of hearing acuity, is a well-established clinical observation. Although several hypotheses have been made about the otic-conductive origin of these complaints, conventional 226-Hz tympanometry has failed to demonstrate any middle ear abnormalities. The aim of this study was to evaluate patients with TMJ disorders with multiple frequency tympanometry (MFT). Prospective clinical study. Outpatient clinic. The population of this study consisted of 40 patients with unilateral TMJ disorders diagnosed for longer than 1 month. After verifying that there were no abnormal otoscopic findings, 226-Hz tympanometry, conventional pure-tone audiometry, brainstem auditory evoked potentials, and MFT were performed. Resonant frequency (RF) values. With the exception of MFT, no abnormal audiologic findings were revealed. The ear ipsilateral to the lesion demonstrated significantly higher (p = 0.002) RF values in comparison to the contralateral ear. The difference in RF values was more obvious in patients aged 45 years or younger. The results of this study imply an increase in the stiffness of the middle ear, which has not been detected by conventional tympanometry. This represents the first concrete documentation of minor alterations in the conductive properties of the middle ear and seems to support the various hypotheses on the middle-ear origin of aural complaints in patients with TMJ disorders. Further studies are needed before a clear insight on the presumably multifactorial pathophysiology of these complaints can finally be reached.

Chronic In Vivo Imaging Shows No Evidence of Dendritic Plasticity or Functional Remapping in the Contralesional Cortex after Stroke

PubMed Central

Johnston, David G.; Denizet, Marie; Mostany, Ricardo

2013-01-01

Most stroke survivors exhibit a partial recovery from their deficits. This presumably occurs because of remapping of lost capabilities to functionally related brain areas. Functional brain imaging studies suggest that remapping in the contralateral uninjured cortex might represent a transient stage of compensatory plasticity. Some postmortem studies have also shown that cortical lesions, including stroke, can trigger dendritic plasticity in the contralateral hemisphere, but the data are controversial. We used longitudinal in vivo two-photon microscopy in the contralateral homotopic cortex to record changes in dendritic spines of layer 5 pyramidal neurons in green fluorescent protein mice. We could not detect de novo growth of dendrites or changes in the density or turnover of spines for up to 4 weeks after stroke. We also used intrinsic optical signal imaging to investigate whether the forepaw (FP) sensory representation is remapped to the spared homotopic cortex after stroke. Stimulation of the contralateral FP reliably produced strong intrinsic signals in the spared hemisphere, but we could never detect a signal with ipsilateral FP stimulation after stroke. This lack of contralateral plasticity at the level of apical dendrites of layer 5 pyramidal neurons and FP sensory maps suggests that the contralesional cortex may not contribute to functional recovery after stroke and that, at least in mice, the peri-infarct cortex plays the dominant role in postischemic plasticity. PMID:22499800

Chronic in vivo imaging shows no evidence of dendritic plasticity or functional remapping in the contralesional cortex after stroke.

PubMed

Johnston, David G; Denizet, Marie; Mostany, Ricardo; Portera-Cailliau, Carlos

2013-04-01

Most stroke survivors exhibit a partial recovery from their deficits. This presumably occurs because of remapping of lost capabilities to functionally related brain areas. Functional brain imaging studies suggest that remapping in the contralateral uninjured cortex might represent a transient stage of compensatory plasticity. Some postmortem studies have also shown that cortical lesions, including stroke, can trigger dendritic plasticity in the contralateral hemisphere, but the data are controversial. We used longitudinal in vivo two-photon microscopy in the contralateral homotopic cortex to record changes in dendritic spines of layer 5 pyramidal neurons in green fluorescent protein mice. We could not detect de novo growth of dendrites or changes in the density or turnover of spines for up to 4 weeks after stroke. We also used intrinsic optical signal imaging to investigate whether the forepaw (FP) sensory representation is remapped to the spared homotopic cortex after stroke. Stimulation of the contralateral FP reliably produced strong intrinsic signals in the spared hemisphere, but we could never detect a signal with ipsilateral FP stimulation after stroke. This lack of contralateral plasticity at the level of apical dendrites of layer 5 pyramidal neurons and FP sensory maps suggests that the contralesional cortex may not contribute to functional recovery after stroke and that, at least in mice, the peri-infarct cortex plays the dominant role in postischemic plasticity.

Tissue resistivities determine the current flow in the cochlea.

PubMed

Micco, Alan Gerard; Richter, Claus-Peter

2006-10-01

In individuals with severe to profound hearing loss, cochlear implants bypass normal inner ear function by applying electrical current directly into the cochlea, thereby stimulating cochlear nerve fibers. Stimulating discrete populations of spiral ganglion cells in cochlear implant users' ears is similar to the encoding of small acoustic frequency bands in a normal-hearing person's ear. Thus, spiral ganglion cells stimulated by an electrode convey the information contained by a small acoustic frequency band. Problems that refer to the current spread and subsequent nonselective stimulation of spiral ganglion cells in the cochlea are reviewed. Cochlear anatomy and tissue properties determine the current path in the cochlea. Current spreads largely via scala tympani and across turns. While most of the current leaves the cochlea via the modiolus, the facial canal and the round window constitute additional natural escape paths for the current from the cochlea. Moreover, degenerative processes change tissue resistivities and thus may affect current spread in the cochlea. Electrode design and coding strategies may result in more spatial stimulation of spiral ganglion cells, resulting in a better performance of the electrode-tissue interface.

Sequential roles of primary somatosensory cortex and posterior parietal cortex in tactile-visual cross-modal working memory: a single-pulse transcranial magnetic stimulation (spTMS) study.

PubMed

Ku, Yixuan; Zhao, Di; Hao, Ning; Hu, Yi; Bodner, Mark; Zhou, Yong-Di

2015-01-01

Both monkey neurophysiological and human EEG studies have shown that association cortices, as well as primary sensory cortical areas, play an essential role in sequential neural processes underlying cross-modal working memory. The present study aims to further examine causal and sequential roles of the primary sensory cortex and association cortex in cross-modal working memory. Individual MRI-based single-pulse transcranial magnetic stimulation (spTMS) was applied to bilateral primary somatosensory cortices (SI) and the contralateral posterior parietal cortex (PPC), while participants were performing a tactile-visual cross-modal delayed matching-to-sample task. Time points of spTMS were 300 ms, 600 ms, 900 ms after the onset of the tactile sample stimulus in the task. The accuracy of task performance and reaction time were significantly impaired when spTMS was applied to the contralateral SI at 300 ms. Significant impairment on performance accuracy was also observed when the contralateral PPC was stimulated at 600 ms. SI and PPC play sequential and distinct roles in neural processes of cross-modal associations and working memory. Copyright © 2015 Elsevier Inc. All rights reserved.

Underwater Noise and the Conservation of Divers’ Hearing: A Review. Volume 1

DTIC Science & Technology

1989-10-01

reflex attenuation, since the tensor tympani is unaffected and since Bell ’ palsy may affect the VIIIth (auditory) nerve as well as the VIlth (facial...studied acoustic reflexes in patients with acute facial nerve paralysis (Bell’s palsy ). These patients had absent stapedius reflexes on the side of the...voluntary middle ear muscle activation. 24 Bell’s palsy cases; attenuation estimated by shift in reflex amplitude- intensity functions (contralateral), re

Developing and Evaluating a Flexible Wireless Microcoil Array Based Integrated Interface for Epidural Cortical Stimulation.

PubMed

Wang, Xing; Chaudhry, Sharjeel A; Hou, Wensheng; Jia, Xiaofeng

2017-02-05

Stroke leads to serious long-term disability. Electrical epidural cortical stimulation has made significant improvements in stroke rehabilitation therapy. We developed a preliminary wireless implantable passive interface, which consists of a stimulating surface electrode, receiving coil, and single flexible passive demodulated circuit printed by flexible printed circuit (FPC) technique and output pulse voltage stimulus by inductively coupling an external circuit. The wireless implantable board was implanted in cats' unilateral epidural space for electrical stimulation of the primary visual cortex (V1) while the evoked responses were recorded on the contralateral V1 using a needle electrode. The wireless implantable board output stable monophasic voltage stimuli. The amplitude of the monophasic voltage output could be adjusted by controlling the voltage of the transmitter circuit within a range of 5-20 V. In acute experiment, cortico-cortical evoked potential (CCEP) response was recorded on the contralateral V1. The amplitude of N2 in CCEP was modulated by adjusting the stimulation intensity of the wireless interface. These results demonstrated that a wireless interface based on a microcoil array can offer a valuable tool for researchers to explore electrical stimulation in research and the dura mater-electrode interface can effectively transmit electrical stimulation.

Optogenetic Stimulation of Peripheral Vagus Nerves using Flexible OLED Display Technology to Treat Chronic Inflammatory Disease and Mental Health Disorders

DTIC Science & Technology

2016-03-31

transcutaneously via the outer ear using a high-resolution, addressable array of organic light emitting diodes (OLEDs) manufactured on a flexible...therapeutic optical stimulation in optogenetically modified neural tissue. Keywords: Optogenetics; neuromodulation; organic light emitting diode ...the outer ear using a high-resolution, two-dimensional (2-D), addressable array of red organic light - emitting diodes (OLEDs) manufactured on a thin

Same-session functional assessment of rat retina and brain with manganese-enhanced MRI

PubMed Central

Bissig, David; Berkowitz, Bruce A.

2013-01-01

Manganese-enhanced MRI (MEMRI) is a powerful non-invasive approach for objectively measuring either retina or binocular visual brain activity in vivo. In this study, we investigated the sensitivity of MEMRI to monocular stimulation using a new protocol for providing within-subject functional comparisons in the retina and brain in the same scanning session. Adult Sprague Dawley or Long–Evans rats had one eye covered with an opaque patch. After intraperitoneal Mn2+ administration on the following day, rats underwent visual stimulation for 8 h. Animals were then anesthetized, and the brain and each eye examined by MEMRI. Function was assessed through pairwise comparisons of the patched (dark-adapted) versus unpatched (light-exposed) eyes, and of differentially-stimulated brain structures – the dorsal lateral geniculate nucleus, superior colliculus, and visual cortical regions – contralateral to the patched versus unpatched eye. As expected, Mn2+ uptake was greater in the outer retina of dark-adapted, relative to light-exposed, eyes (P<0.05). Contralateral to the unpatched eye, significantly more Mn2+ uptake was found throughout the visual brain regions than in the corresponding structures contralateral to the patched eye (P<0.05). Notably, this regional pattern of activity corresponded well to previous work with monocular stimulation. No stimulation-dependent differences in Mn2+ uptake were observed in negative control brain regions (P>0.05). Post-hoc assessment of functional data by animal age and strain revealed no significant effects. These results demonstrate, for the first time, the acquisition of functional MRI data from the eye and visual brain regions in a single scanning session. PMID:21749922

Targeted mini-strokes produce changes in interhemispheric sensory signal processing that are indicative of disinhibition within minutes.

PubMed

Mohajerani, Majid H; Aminoltejari, Khatereh; Murphy, Timothy H

2011-05-31

Most processing of sensation involves the cortical hemisphere opposite (contralateral) to the stimulated limb. Stroke patients can exhibit changes in the interhemispheric balance of sensory signal processing. It is unclear whether these changes are the result of poststroke rewiring and experience, or whether they could result from the immediate effect of circuit loss. We evaluated the effect of mini-strokes over short timescales (<2 h) where cortical rewiring is unlikely by monitoring sensory-evoked activity throughout much of both cortical hemispheres using voltage-sensitive dye imaging. Blockade of a single pial arteriole within the C57BL6J mouse forelimb somatosensory cortex reduced the response evoked by stimulation of the limb contralateral to the stroke. However, after stroke, the ipsilateral (uncrossed) forelimb response within the unaffected hemisphere was spared and became independent of the contralateral forelimb cortex. Within the unaffected hemisphere, mini-strokes in the opposite hemisphere significantly enhanced sensory responses produced by stimulation of either contralateral or ipsilateral pathways within 30-50 min of stroke onset. Stroke-induced enhancement of responses within the spared hemisphere was not reproduced by inhibition of either cortex or thalamus using pharmacological agents in nonischemic animals. I/LnJ acallosal mice showed similar rapid interhemispheric redistribution of sensory processing after stroke, suggesting that subcortical connections and not transcallosal projections were mediating the novel activation patterns. Thalamic inactivation before stroke prevented the bilateral rearrangement of sensory responses. These findings suggest that acute stroke, and not merely loss of activity, activates unique pathways that can rapidly redistribute function within the spared cortical hemisphere.

Electric-acoustic stimulation suppresses tinnitus in a subject with high-frequency single-sided deafness.

PubMed

Mertens, Griet; Van Rompaey, Vincent; Van de Heyning, Paul

2018-05-17

A suggested solution to suppress tinnitus is to restore the normal sensory input. This is based on the auditory deprivation hypothesis. It is known that hearing aids can provide sufficient activation of the auditory nervous system and reduce tinnitus in subjects with mild to moderate hearing loss and that cochlear implantation can reduce tinnitus in subjects with severe to profound hearing loss. This applies to subjects with single-sided deafness (SSD) or bilateral hearing loss. To investigate if electric-acoustic stimulation (EAS) can reduce severe tinnitus in a subject with residual hearing in the ipsilateral ear and contralateral normal hearing (high-frequency SSD) by restoring the auditory input. Tinnitus reduction was investigated for 1 year after implantation in a subject with high-frequency SSD, who uses EAS, and was compared to 11 subjects with a cochlear implant (CI) with SSD. The Visual Analogue Scale (VAS) and the Tinnitus Questionnaire (TQ) were administered pre-operatively and at 1, 3, 6, and 12 months after implantation. Significant tinnitus reduction was observed 1 month after implantation on the VAS in the subjects with SSD using a CI. Tinnitus reduction was also observed in the subject with high-frequency SSD using EAS. A further decrease was observed 3 months after implantation. The TQ and VAS scores remained stable up to 1 year after implantation. A CI can significantly reduce ipsilateral severe tinnitus in a subject with SSD. Ipsilateral severe tinnitus can also be reduced using EAS in subjects with high-frequency SSD.

[Effect of the middle ear status on the recording of vestibular evoked myogenic potential--VEMP].

PubMed

Kurzyna, Agnieszka; Hassmann-Poznańska, Elzbieta; Topolska, Małgorzata Maria

2005-01-01

The aim of this study was to assess the effect of the middle ear status on the recording of air- and bone-conducted vestibular evoked myogenic potential. Forty eight children were included in the study, ranging in age from 4 to 10 years. All of the children underwent otoscopy, pure tone audiometry, tympanometry and air- and bone-conducted VEMP in response to click. There were 3 groups according to the condition of the middle ear: group I--52 ears (type A and C1 tympanogram, pure tone average < or = 20 dB), group II--23 ears (type C2 and B tympanogram, pure tone average < or = 20 dB), group III--21 (type B tympanogram, pure tone average > 20 dB). The threshold, presence of correct waveform morphology of the response and latency was evaluated. The condition of the middle ear has no significant effect on the recording of VEMP and mean level of the response threshold with bone stimulation, based on the performed studies. However, with air stimulation it has effect on the recording of VEMP, increase of the mean threshold response and shortening of latency p13 and n23.

Use of rapid prototyping in prosthetic auricular restoration.

PubMed

Turgut, Gursel; Sacak, Bulent; Kiran, Kazim; Bas, Lutfu

2009-03-01

Reconstructing auricular defects is a challenging task for facial reconstructive surgeons. Although autologous reconstruction is the first choice for reconstruction, there may be circumstances of inconvenience such as previously attempted surgery, radiotherapy, systemic conditions, or patient's wish. Auricular restorations with facial prosthesis have produced promising results, but there are still problems to be tackled for improved results. Rapid prototyping in the production of an auricular prosthesis uses the mirror image of contralateral ear and produces excellent forms, eliminating the subjective perception of the prosthodontist. Rapid prototyping also lowers the production costs by reducing the need for several sessions in the process of producing the prostheses. Between 2004 and 2007, 10 patients applied to our department with the absence of an ear on a single side. All patients were male, with an average age of 23.1 years. The etiology for the loss of the ear was mostly tumors, followed by congenital deformities and trauma, respectively. In this study, we present our application of rapid prototyping technique and report our case series of 10 patients, two of which are presented in detail.

Peptide-induced prostaglandin biosynthesis in the renal-vein-constricted kidney

PubMed Central

Myers, Stuart I.; Zipser, Robert; Needleman, Philip

1981-01-01

The ipsilateral kidney was removed from a rabbit 48h after unilateral partial renal-vein-constriction and was perfused with Krebs–Henseleit media at 37°C. Hourly administration of a fixed dose of bradykinin to the renal-vein-constricted kidney demonstrated a marked time-dependent increase in the release of bioassayable prostaglandin E2 and thromboxane A2 into the venous effluent as compared with the response of the contralateral control kidney. The renal-vein-constricted kidney produced up to 60 times more prostaglandin E2 in response to bradykinin after 6h of perfusion as compared with the contralateral kidney; thromboxane A2 was not demonstratable in the contralateral kidney. Inhibition of protein synthesis de novo in the perfused renal-vein-constricted kidney with cycloheximide lessened the hormone-stimulated increase in prostaglandin E2 by 94% and in thromboxane A2 by 90% at 6h of perfusion. Covalent acetylation of the renal cyclo-oxygenase by prior oral administration of aspirin to the rabbit inhibited initial bradykinin-stimulated prostaglandin E2 biosynthesis 71% at 1h of perfusion. However, there was total recovery from aspirin in the renal-vein-constricted kidney by 2h of perfusion after bradykinin stimulation. Total cyclo-oxygenase activity as measured by [14C]arachidonate metabolism to labelled prostaglandins by renal cortical and renal medullary microsomal fractions prepared from 6h-perfused kidneys demonstrated that renal-vein-constricted kidney-cortical cyclo-oxygenase activity was significantly greater than the contralateral-kidney-cortical conversion, whereas medullary arachidonate metabolism was comparable in both the renal-vein-constricted kidney and contralateral kidney. These data suggest that perfusion of a renal-vein-constricted kidney initiates a time-dependent induction of synthesis of prostaglandin-producing enzymes, which appear to be primarily localized in the renal cortex. The presence of the synthetic capacity to generate very potent vasodilator and vasoconstrictor prostaglandins in the renal cortex suggests that these substances could mediate or modulate changes in renal vascular resistance in pathological states. PMID:6798974

Features of the Retinotopic Representation in the Visual Wulst of a Laterally Eyed Bird, the Zebra Finch (Taeniopygia guttata)

PubMed Central

Michael, Neethu; Löwel, Siegrid; Bischof, Hans-Joachim

2015-01-01

The visual wulst of the zebra finch comprises at least two retinotopic maps of the contralateral eye. As yet, it is not known how much of the visual field is represented in the wulst neuronal maps, how the organization of the maps is related to the retinal architecture, and how information from the ipsilateral eye is involved in the activation of the wulst. Here, we have used autofluorescent flavoprotein imaging and classical anatomical methods to investigate such characteristics of the most posterior map of the multiple retinotopic representations. We found that the visual wulst can be activated by visual stimuli from a large part of the visual field of the contralateral eye. Horizontally, the visual field representation extended from -5° beyond the beak tip up to +125° laterally. Vertically, a small strip from -10° below to about +25° above the horizon activated the visual wulst. Although retinal ganglion cells had a much higher density around the fovea and along a strip extending from the fovea towards the beak tip, these areas were not overrepresented in the wulst map. The wulst area activated from the foveal region of the ipsilateral eye, overlapped substantially with the middle of the three contralaterally activated regions in the visual wulst, and partially with the other two. Visual wulst activity evoked by stimulation of the frontal visual field was stronger with contralateral than with binocular stimulation. This confirms earlier electrophysiological studies indicating an inhibitory influence of the activation of the ipsilateral eye on wulst activity elicited by stimulating the contralateral eye. The lack of a foveal overrepresentation suggests that identification of objects may not be the primary task of the zebra finch visual wulst. Instead, this brain area may be involved in the processing of visual information necessary for spatial orientation. PMID:25853253

Transtympanic injections of N-acetylcysteine for the prevention of cisplatin-induced ototoxicity: a feasible method with promising efficacy.

PubMed

Riga, Maria G; Chelis, Leonidas; Kakolyris, Stylianos; Papadopoulos, Stergios; Stathakidou, Sofia; Chamalidou, Eleni; Xenidis, Nikolaos; Amarantidis, Kyriakos; Dimopoulos, Prokopios; Danielides, Vasilios

2013-02-01

Ototoxicity is a common and irreversible adverse effect of cisplatin treatment with great impact on the patients' quality of life. N-acetylcysteine is a low-molecular-weight agent which has shown substantial otoprotective activity. The role of transtympanic infusions of N-acetylcysteine was examined in a cohort of patients treated with cisplatin-based regimens. Twenty cisplatin-treated patients were subjected, under local anesthesia, to transtympanic N-acetylcysteine (10%) infusions in 1 ear, during the hydration procedure preceding intravenous effusion of cisplatin. The contralateral ear was used as control. The number of transtympanic infusions was respective to the number of administered cycles. Hearing acuity was evaluated before each cycle with pure tone audiometry by an audiologist blinded to the treated ear. A total of 84 transtympanic infusions were performed. In treated ears, no significant changes in auditory thresholds were recorded. In the control ears cisplatin induced a significant decrease of auditory thresholds at the 8000 Hz frequency band (P=0.008). At the same frequency (8000 Hz), the changes in auditory thresholds were significantly larger for the control ears than the treated ones (P=0.005). An acute pain starting shortly after the injection and lasting for a few minutes seemed to be the only significant adverse effect. Transtympanic injections of N-acetylcysteine seem to be a feasible and effective otoprotective strategy for the prevention of cisplatin-induced ototoxicity. Additional studies are required to further clarify the efficiency of this treatment and determine the optimal dosage and protocol.

Auditory function after application of ototopical vancomycin and mupirocin solutions in a murine model.

PubMed

Rutherford, Kimberley D; Kavanagh, Katherine; Parham, Kourosh

2011-03-01

To determine whether mupirocin (440 µg/mL) and vancomycin otic drops (25 mg/mL) show evidence of ototoxicity in CBA/J mice immediately following a 7-day course of daily intratympanic (IT) injections and 1 month following treatment. Nonrandomized controlled trial. Academic hospital laboratory. Twenty CBA/J mice. Mean auditory brainstem response (ABR) thresholds increased in all drug- and saline-treated ears immediately after 7 days of IT injections but returned to baseline for most stimulus frequencies by 30 days later. This finding appeared to be correlated with the presence and subsequent resolution of tympanic membrane (TM) perforations and granulation tissue at the injection sites. Mupirocin-treated ears showed no significant difference in ABR thresholds compared to saline-treated ears. No significant differences were noted between vancomycin- and saline-treated ears, but there was a significant interaction between testing day and stimulus frequency (P < .001). Further analysis revealed that ABR thresholds at 32 kHz remained significantly elevated in vancomycin-treated mice despite the resolution of TM perforations and granulation tissue 30 days after completion of IT injections (95% confidence interval, -13.5 to -5.5, P < .01). Although IT application of mupirocin solution (440 µg/mL) caused no significant change in the ABR thresholds in a murine model, vancomycin solution (25 mg/mL) resulted in high-frequency threshold elevations in both the ear directly injected and the contralateral ear. Mupirocin solution may be beneficial in managing otitis externa and media caused by resistant pathogens. Further studies of ototopical vancomycin are needed to define parameters governing its safe use.

Aural Acoustic Stapedius-Muscle Reflex Threshold Procedures to Test Human Infants and Adults.

PubMed

Keefe, Douglas H; Feeney, M Patrick; Hunter, Lisa L; Fitzpatrick, Denis F

2017-02-01

Power-based procedures are described to measure acoustic stapedius-muscle reflex threshold and supra-threshold responses in human adult and infant ears at frequencies from 0.2 to 8 kHz. The stimulus set included five clicks in which four pulsed activators were placed between each pair of clicks, with each stimulus set separated from the next by 0.79 s to allow for reflex decay. Each click response was used to detect the presence of reflex effects across frequency that were elicited by a pulsed broadband-noise or tonal activator in the ipsilateral or contralateral test ear. Acoustic reflex shifts were quantified in terms of the difference in absorbed sound power between the initial baseline click and the later four clicks in each set. Acoustic reflex shifts were measured over a 40-dB range of pulsed activators, and the acoustic reflex threshold was objectively calculated using a maximum 10 likelihood procedure. To illustrate the principles underlying these new reflex tests, reflex shifts in absorbed sound power and absorbance are presented for data acquired in an adult ear with normal hearing and in two infant ears in the initial and follow-up newborn hearing screening exams, one with normal hearing and the other with a conductive hearing loss. The use of absorbed sound power was helpful in classifying an acoustic reflex shift as present or absent. The resulting reflex tests are in use in a large study of wideband clinical diagnosis and monitoring of middle-ear and cochlear function in infant and adult ears.

Binaural interaction in low-frequency neurons in inferior colliculus of the cat. I. Effects of long interaural delays, intensity, and repetition rate on interaural delay function.

PubMed

Kuwada, S; Yin, T C

1983-10-01

Detailed, quantitative studies were made of the interaural phase sensitivity of 197 neurons with low best frequency in the inferior colliculus (IC) of the barbiturate-anesthetized cat. We analyzed the responses of single cells to interaural delays in which tone bursts were delivered to the two ears via sealed earphones and the onset of the tone to one ear with respect to the other was varied. For most (80%) cells the discharge rate is a cyclic function of interaural delay at a period corresponding to that of the stimulating frequency. The cyclic nature of the interaural delay curve indicates that these cells are sensitive to the interaural phase difference. These cells are distributed throughout the low-frequency zone of the IC, but they are less numerous in the medial and caudal zones. Cells with a wide variety of response patterns will exhibit interaural phase sensitivities at stimulating frequencies up to 3,100 Hz, although above 2,500 Hz the number of such cells decrease markedly. Using dichotic stimuli we could study the cell's sensitivity to the onset delay and interaural phase independently. The large majority of IC cells respond only to changes in interaural phase, with no sensitivity to the onset delay. However, a small number (7%) of cells exhibit a sensitivity to the onset delay as well as to the interaural phase disparity, and most of these cells show an onset response. The effects of changing the stimulus intensity equally to both ears or of changing the interaural intensity difference on the mean interaural phase were studied. While some neurons are not affected by level changes, others exhibit systematic phase shifts for both average and interaural intensity variations, and there is a continuous distribution of sensitivities between these extremes. A few cells also showed systematic changes in the shape of the interaural delay curves as a function of interaural intensity difference, especially at very long delays. These shifts can be interpreted as a form of time-intensity trading. A few cells demonstrated orderly changes in the interaural delay curve as the repetition rate of the stimulus was varied. Some of these changes are consonant with an inhibitory effect that occurs at stimulus offset. The responses of the neurons show a strong bias for stimuli that would originate from he contralateral sound field; 77% of the responses display mean interaural phase angles that are less than 0.5 of a cycle, which are delays to the ipsilateral tone.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of contralateral white noise stimulation on distortion product otoacoustic emissions in myasthenic patients.

PubMed

Di Girolamo, S; d'Ecclesia, A; Quaranta, N; Garozzo, A; Evoli, A; Paludetti, G

2001-12-01

Myasthenia gravis (MG) induces a reduction of transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) that reverses partially after administration of an acetylcholinesterase (AChE) inhibitor. In normal subjects a contralateral acoustic stimulation (CAS) produces an amplitude reduction of TEOAEs and DPOAEs. This effect, called contralateral suppression (CS), is mediated by the efferent auditory system. Twenty subjects affected by MG underwent DPOAE recording with and without contralateral white noise in a drug-free baseline period ('basal') and 1 h ('post') after administration of a reversible AChE inhibitor. In 'basal' condition CAS did not induce significant DPOAE amplitude changes but a paradoxical slight increase was observed. After drug administration, CAS produced a significant decrease of DPOAE amplitudes for middle frequencies (f(2) between 1306 and 2600 Hz). In normal controls CAS caused a significant decrease (P<0.001) for all frequencies. The amount of CS in controls and in the MG 'post' condition was not significantly different. The increased acetylcholine (ACh) availability following drug consumption seems to partially restore outer hair cell function and enhances their electromotility; a further influx of ACh due to CAS yields to restoration of the CS. These findings also suggest that DPOAEs may be useful in the diagnosis of MG and for monitoring the effectiveness of treatment.

Gender Differences in Laser Acupuncture—Results of a Crossover Study with Green and Yellow Laser at the Ear Point Shenmen

PubMed Central

Litscher, Daniela; Wang, Junying; Li, Guangzong; Bosch, Peggy; Wang, Lu

2018-01-01

Background: One of the most commonly used auricular acupuncture points selected for different pain treatment regimens is Shenmen. This point on the ear has been recognized as having a wide number of applications, as found by scientific investigation. Methods: Within this crossover study, the ear acupoint Shenmen was stimulated with two different kinds of laser (green, 532 nm and yellow, 589 nm) in 22 healthy volunteers (13 female, 9 male; mean age ± SD = 25.3 ± 4.1 years; range 21–36 years). Both green and yellow lasers were used for 15 min in the same volunteers in two different sessions. Results: The most prominent finding was that systolic blood pressure decreased significantly (p = 0.048) after yellow laser stimulation. Heart rate also decreased significantly (p < 0.001), whereas heart rate variability ratio low frequency (LF)/high frequency (HF) (p < 0.001) increased. The effects were significantly more pronounced in females than in males. In addition, the temperature was measured, and temperature increases were demonstrated at different locations on the ear using imaging methods. Conclusions: This study shows evidence of the effect of auricular laser acupuncture. However, a comparison with other publications was impossible because this is the first study using green and yellow laser stimulation on the ear. PMID:29543742

A pilot study of contralateral homonymous muscle activity simulated electrical stimulation in chronic hemiplegia.

PubMed

Osu, Rieko; Otaka, Yohei; Ushiba, Junichi; Sakata, Sachiko; Yamaguchi, Tomofumi; Fujiwara, Toshiyuki; Kondo, Kunitsugu; Liu, Meigen

2012-01-01

For the recovery of hemiparetic hand function, a therapy was developed called contralateral homonymous muscle activity stimulated electrical stimulation (CHASE), which combines electrical stimulation and bilateral movements, and its feasibility was studied in three chronic stroke patients with severe hand hemiparesis. Patients with a subcortical lesion were asked to extend their wrist and fingers bilaterally while an electromyogram (EMG) was recorded from the extensor carpi radialis (ECR) muscle in the unaffected hand. Electric stimulation was applied to the homonymous wrist and finger extensors of the affected side. The intensity of the electrical stimulation was computed based on the EMG and scaled so that the movements of the paretic hand looked similar to those of the unaffected side. The patients received 30-minutes of therapy per day for 2 weeks. Improvement in the active range of motion of wrist extension was observed for all patients. There was a decrease in the scores of modified Ashworth scale in the flexors. Fugl-Meyer assessment scores of motor function of the upper extremities improved in two of the patients. The results suggest a positive outcome can be obtained using the CHASE system for upper extremity rehabilitation of patients with severe hemiplegia.

Subthalamic Nucleus Stimulation Modulates Motor Cortex Oscillatory Activity in Parkinson's Disease

ERIC Educational Resources Information Center

Devos, D.; Labyt, E.; Derambure, P.; Bourriez, J. L.; Cassim, F.; Reyns, N.; Blond, S.; Guieu, J. D.; Destee, A.; Defebvre, L.

2004-01-01

In Parkinson's disease, impaired motor preparation has been related to an increased latency in the appearance of movement-related desynchronization (MRD) throughout the contralateral primary sensorimotor (PSM) cortex. Internal globus pallidus (GPi) stimulation improved movement desynchronization over the PSM cortex during movement execution but…

Functional connectivity between right and left mesial temporal structures.

PubMed

Lacuey, Nuria; Zonjy, Bilal; Kahriman, Emine S; Kaffashi, Farhad; Miller, Jonathan; Lüders, Hans O

2015-09-01

The aim of this study is to investigate functional connectivity between right and left mesial temporal structures using cerebrocerebral evoked potentials. We studied seven patients with drug-resistant focal epilepsy who were explored with stereotactically implanted depth electrodes in bilateral hippocampi. In all patients cerebrocerebral evoked potentials evoked by stimulation of the fornix were evaluated as part of a research project assessing fornix stimulation for control of hippocampal seizures. Stimulation of the fornix elicited responses in the ipsilateral hippocampus in all patients with a mean latency of 4.6 ms (range 2-7 ms). Two patients (29 %) also had contralateral hippocampus responses with a mean latency of 7.5 ms (range 5-12 ms) and without involvement of the contralateral temporal neocortex or amygdala. This study confirms the existence of connections between bilateral mesial temporal structures in some patients and explains seizure discharge spreading between homotopic mesial temporal structures without neocortical involvement.

The physiological basis of the effects of intermittent theta burst stimulation of the human motor cortex.

PubMed

Di Lazzaro, V; Pilato, F; Dileone, M; Profice, P; Oliviero, A; Mazzone, P; Insola, A; Ranieri, F; Meglio, M; Tonali, P A; Rothwell, J C

2008-08-15

Theta burst stimulation (TBS) is a form of repetitive transcranial magnetic stimulation (TMS). When applied to motor cortex it leads to after-effects on corticospinal and corticocortical excitability that may reflect LTP/LTD-like synaptic effects. An inhibitory form of TBS (continuous, cTBS) suppresses MEPs, and spinal epidural recordings show this is due to suppression of the I1 volley evoked by TMS. Here we investigate whether the excitatory form of TBS (intermittent, iTBS) affects the same I-wave circuitry. We recorded corticospinal volleys evoked by single pulse TMS of the motor cortex before and after iTBS in three conscious patients who had an electrode implanted in the cervical epidural space for the control of pain. As in healthy subjects, iTBS increased MEPs, and this was accompanied by a significant increase in the amplitude of later I-waves, but not the I1 wave. In two of the patients we tested the excitability of the contralateral cortex and found a significant suppression of the late I-waves. The extent of the changes varied between the three patients, as did their age. To investigate whether age might be a significant contributor to the variability we examined the effect of iTBS on MEPs in 18 healthy subjects. iTBS facilitated MEPs evoked by TMS of the conditioned hemisphere and suppressed MEPs evoked by stimulation of the contralateral hemisphere. There was a slight but non-significant decline in MEP facilitation with age, suggesting that interindividual variability was more important than age in explaining our data. In a subgroup of 10 subjects we found that iTBS had no effect on the duration of the ipsilateral silent period suggesting that the reduction in contralateral MEPs was not due to an increase in ongoing transcallosal inhibition. In conclusion, iTBS affects the excitability of excitatory synaptic inputs to pyramidal tract neurones that are recruited by a TMS pulse, both in the stimulated hemisphere and in the contralateral hemisphere. However the circuits affected differ from those influenced by the inhibitory, cTBS, protocol. The implication is that cTBS and iTBS may have different therapeutic targets.

Structural Diversity in the Inner Ear of Teleost Fishes: Implications for Connections to the Mauthner Cell

NASA Technical Reports Server (NTRS)

Popper, Arthur N.; Edds-Walton, Peggy L.

1995-01-01

A body of literature suggests that the Mauthner cell startle response can be elicited by stimulation of the ear. While we know that there are projections to the M-cell from the ear, the specific endorgan(s) of the ear projecting to the M-cell are not known. Moreover, there are many reasons to question whether there is one pattern of inner ear to M-cell connection or whether the endorgan(s) projection to the M-cell varies in species that have different hearing capabilities of hearing structures. In this paper, we briefly review the structure of fish ears, with an emphasis on structural regionalization within the ear. We also review the central projections of the ear, along with a discussion of the limited data on projections to the M-cell.

Magnetic Stimulation Studies of Foveal Representation

ERIC Educational Resources Information Center

Lavidor, Michal; Walsh, Vincent

2004-01-01

The right and left visual fields each project to the contralateral cerebral hemispheres, but the extent of the functional overlap of the two hemifields along the vertical meridian is still under debate. After presenting the spatial, temporal, and functional specifications of Transcranial Magnetic Stimulation (TMS), we show that TMS is particularly…

Affect of deep brain stimulation on limb paresis after stroke.

PubMed

Phillips, N I; Bhakta, B B

2000-07-15

A deep brain stimulator was implanted in the periventricular grey matter of the third ventricle for pain after stroke in a man aged 48 years. As well as a beneficial analgesic effect, the patient reported improved function in the contralateral paretic arm, which was confirmed on formal testing.

Impact of a Moving Noise Masker on Speech Perception in Cochlear Implant Users

PubMed Central

Weissgerber, Tobias; Rader, Tobias; Baumann, Uwe

2015-01-01

Objectives Previous studies investigating speech perception in noise have typically been conducted with static masker positions. The aim of this study was to investigate the effect of spatial separation of source and masker (spatial release from masking, SRM) in a moving masker setup and to evaluate the impact of adaptive beamforming in comparison with fixed directional microphones in cochlear implant (CI) users. Design Speech reception thresholds (SRT) were measured in S0N0 and in a moving masker setup (S0Nmove) in 12 normal hearing participants and 14 CI users (7 subjects bilateral, 7 bimodal with a hearing aid in the contralateral ear). Speech processor settings were a moderately directional microphone, a fixed beamformer, or an adaptive beamformer. The moving noise source was generated by means of wave field synthesis and was smoothly moved in a shape of a half-circle from one ear to the contralateral ear. Noise was presented in either of two conditions: continuous or modulated. Results SRTs in the S0Nmove setup were significantly improved compared to the S0N0 setup for both the normal hearing control group and the bilateral group in continuous noise, and for the control group in modulated noise. There was no effect of subject group. A significant effect of directional sensitivity was found in the S0Nmove setup. In the bilateral group, the adaptive beamformer achieved lower SRTs than the fixed beamformer setting. Adaptive beamforming improved SRT in both CI user groups substantially by about 3 dB (bimodal group) and 8 dB (bilateral group) depending on masker type. Conclusions CI users showed SRM that was comparable to normal hearing subjects. In listening situations of everyday life with spatial separation of source and masker, directional microphones significantly improved speech perception with individual improvements of up to 15 dB SNR. Users of bilateral speech processors with both directional microphones obtained the highest benefit. PMID:25970594

Topographic analysis of the skull vibration-induced nystagmus test with piezoelectric accelerometers and force sensors.

PubMed

Dumas, Georges; Lion, Alexis; Perrin, Philippe; Ouedraogo, Evariste; Schmerber, Sébastien

2016-03-23

Vibration-induced nystagmus is elicited by skull or posterior cervical muscle stimulations in patients with vestibular diseases. Skull vibrations delivered by the skull vibration-induced nystagmus test are known to stimulate the inner ear structures directly. This study aimed to measure the vibration transfer at different cranium locations and posterior cervical regions to contribute toward stimulus topographic optimization (experiment 1) and to determine the force applied on the skull with a hand-held vibrator to study the test reproducibility and provide recommendations for good clinical practices (experiment 2). In experiment 1, a 100 Hz hand-held vibrator was applied on the skull (vertex, mastoids) and posterior cervical muscles in 11 healthy participants. Vibration transfer was measured by piezoelectric sensors. In experiment 2, the vibrator was applied 30 times by two experimenters with dominant and nondominant hands on a mannequin equipped to measure the force. Experiment 1 showed that after unilateral mastoid vibratory stimulation, the signal transfer was higher when recorded on the contralateral mastoid than on the vertex or posterior cervical muscles (P<0.001). No difference was observed between the different vibratory locations when vibration transfer was measured on vertex and posterior cervical muscles. Experiment 2 showed that the force applied to the mannequin varied according to the experimenters and the handedness, higher forces being observed with the most experienced experimenter and with the dominant hand (10.3 ± 1.0 and 7.8 ± 2.9 N, respectively). The variation ranged from 9.8 to 29.4% within the same experimenter. Bone transcranial vibration transfer is more efficient from one mastoid to the other mastoid than other anatomical sites. The mastoid is therefore the optimal site for skull vibration-induced nystagmus test in patients with unilateral vestibular lesions and enables a stronger stimulation of the healthy side. In clinical practice, the vibrator should be placed on the mastoid and should be held by the clinician's dominant hand.

Granger causal time-dependent source connectivity in the somatosensory network

NASA Astrophysics Data System (ADS)

Gao, Lin; Sommerlade, Linda; Coffman, Brian; Zhang, Tongsheng; Stephen, Julia M.; Li, Dichen; Wang, Jue; Grebogi, Celso; Schelter, Bjoern

2015-05-01

Exploration of transient Granger causal interactions in neural sources of electrophysiological activities provides deeper insights into brain information processing mechanisms. However, the underlying neural patterns are confounded by time-dependent dynamics, non-stationarity and observational noise contamination. Here we investigate transient Granger causal interactions using source time-series of somatosensory evoked magnetoencephalographic (MEG) elicited by air puff stimulation of right index finger and recorded using 306-channel MEG from 21 healthy subjects. A new time-varying connectivity approach, combining renormalised partial directed coherence with state space modelling, is employed to estimate fast changing information flow among the sources. Source analysis confirmed that somatosensory evoked MEG was mainly generated from the contralateral primary somatosensory cortex (SI) and bilateral secondary somatosensory cortices (SII). Transient Granger causality shows a serial processing of somatosensory information, 1) from contralateral SI to contralateral SII, 2) from contralateral SI to ipsilateral SII, 3) from contralateral SII to contralateral SI, and 4) from contralateral SII to ipsilateral SII. These results are consistent with established anatomical connectivity between somatosensory regions and previous source modeling results, thereby providing empirical validation of the time-varying connectivity analysis. We argue that the suggested approach provides novel information regarding transient cortical dynamic connectivity, which previous approaches could not assess.

Does unilateral basal ganglia activity functionally influence the contralateral side? What we can learn from STN stimulation in patients with Parkinson's disease.

PubMed

Brun, Yohann; Karachi, Carine; Fernandez-Vidal, Sara; Jodoin, Nicolas; Grabli, David; Bardinet, Eric; Mallet, Luc; Agid, Yves; Yelnik, Jerome; Welter, Marie-Laure

2012-09-01

In humans, the control of voluntary movement, in which the corticobasal ganglia (BG) circuitry participates, is mainly lateralized. However, several studies have suggested that both the contralateral and ipsilateral BG systems are implicated during unilateral movement. Bilateral improvement of motor signs in patients with Parkinson's disease (PD) has been reported with unilateral lesion or high-frequency stimulation (HFS) of the internal part of the globus pallidus or the subthalamic nucleus (STN-HFS). To decipher the mechanisms of production of ipsilateral movements induced by the modulation of unilateral BG circuitry activity, we recorded left STN neuronal activity during right STN-HFS in PD patients operated for bilateral deep brain stimulation. Left STN single cells were recorded in the operating room during right STN-HFS while patients experienced, or did not experience, right stimulation-induced dyskinesias. Most of the left-side STN neurons (64%) associated with the presence of right dyskinesias were inhibited, with a significant decrease in burst and intraburst frequencies. In contrast, left STN neurons not associated with right dyskinesias were mainly activated (48%), with a predominant increase 4-5 ms after the stimulation pulse and a decrease in oscillatory activity. This suggests that unilateral neuronal STN modulation is associated with changes in the activity of the contralateral STN. The fact that one side of the BG system can influence the functioning of the other could explain the occurrence of bilateral dyskinesias and motor improvement observed in PD patients during unilateral STN-HFS, as a result of a bilateral disruption of the pathological activity in the corticosubcortical circuitry.

Astrocyte Hypertrophy and Microglia Activation in the Rat Auditory Midbrain Is Induced by Electrical Intracochlear Stimulation.

PubMed

Rosskothen-Kuhl, Nicole; Hildebrandt, Heika; Birkenhäger, Ralf; Illing, Robert-Benjamin

2018-01-01

Neuron-glia interactions contribute to tissue homeostasis and functional plasticity in the mammalian brain, but it remains unclear how this is achieved. The potential of central auditory brain tissue for stimulation-dependent cellular remodeling was studied in hearing-experienced and neonatally deafened rats. At adulthood, both groups received an intracochlear electrode into the left cochlea and were continuously stimulated for 1 or 7 days after waking up from anesthesia. Normal hearing and deafness were assessed by auditory brainstem responses (ABRs). The effectiveness of stimulation was verified by electrically evoked ABRs as well as immunocytochemistry and in situ hybridization for the immediate early gene product Fos on sections through the auditory midbrain containing the inferior colliculus (IC). Whereas hearing-experienced animals showed a tonotopically restricted Fos response in the IC contralateral to electrical intracochlear stimulation, Fos-positive neurons were found almost throughout the contralateral IC in deaf animals. In deaf rats, the Fos response was accompanied by a massive increase of GFAP indicating astrocytic hypertrophy, and a local activation of microglial cells identified by IBA1. These glia responses led to a noticeable increase of neuron-glia approximations. Moreover, staining for the GABA synthetizing enzymes GAD65 and GAD67 rose significantly in neuronal cell bodies and presynaptic boutons in the contralateral IC of deaf rats. Activation of neurons and glial cells and tissue re-composition were in no case accompanied by cell death as would have been apparent by a Tunel reaction. These findings suggest that growth and activity of glial cells is crucial for the local adjustment of neuronal inhibition to neuronal excitation.

Astrocyte Hypertrophy and Microglia Activation in the Rat Auditory Midbrain Is Induced by Electrical Intracochlear Stimulation

PubMed Central

Rosskothen-Kuhl, Nicole; Hildebrandt, Heika; Birkenhäger, Ralf; Illing, Robert-Benjamin

2018-01-01

Neuron–glia interactions contribute to tissue homeostasis and functional plasticity in the mammalian brain, but it remains unclear how this is achieved. The potential of central auditory brain tissue for stimulation-dependent cellular remodeling was studied in hearing-experienced and neonatally deafened rats. At adulthood, both groups received an intracochlear electrode into the left cochlea and were continuously stimulated for 1 or 7 days after waking up from anesthesia. Normal hearing and deafness were assessed by auditory brainstem responses (ABRs). The effectiveness of stimulation was verified by electrically evoked ABRs as well as immunocytochemistry and in situ hybridization for the immediate early gene product Fos on sections through the auditory midbrain containing the inferior colliculus (IC). Whereas hearing-experienced animals showed a tonotopically restricted Fos response in the IC contralateral to electrical intracochlear stimulation, Fos-positive neurons were found almost throughout the contralateral IC in deaf animals. In deaf rats, the Fos response was accompanied by a massive increase of GFAP indicating astrocytic hypertrophy, and a local activation of microglial cells identified by IBA1. These glia responses led to a noticeable increase of neuron–glia approximations. Moreover, staining for the GABA synthetizing enzymes GAD65 and GAD67 rose significantly in neuronal cell bodies and presynaptic boutons in the contralateral IC of deaf rats. Activation of neurons and glial cells and tissue re-composition were in no case accompanied by cell death as would have been apparent by a Tunel reaction. These findings suggest that growth and activity of glial cells is crucial for the local adjustment of neuronal inhibition to neuronal excitation. PMID:29520220

Unilateral and Immediate Stimulation of Acupuncture Points Xiaohai (SI8) and Jianwaishu (SI14) of the Small Intestine Meridian Increases Electromyographic Activity and Strength in the Ipsilateral and Contralateral Upper Trapezius Muscle.

PubMed

de Souza, Leandro L; de Araujo, Fernanda L B; da Silva, Fernanda A M; Mucciaroni, Thaís S; de Araujo, João E

2016-10-01

We previously showed that a yin meridian of the upper limb decreased electromyographic activity (root mean square) and muscle strength ipsilateral and contralateral to the side of stimulation. Here, we tested the upper trapezius (UT) muscle response after stimulation of a yang meridian of the upper limb, the small intestine (SI). Thirty-eight healthy volunteers were randomized into the following groups: UT muscle (SI14), distant of the UT muscle (SI8), without stimulation (CG), and sham (R3). An acupuncturist certificated by the Brazilian Society of Physical Therapists and Acupuncturists performed the needle insertion. Each volunteer received only one stimulation to the right upper limb. The evaluation occurred before, 5 minutes after, and 20 minutes after needle withdrawal. The root mean square activity increased on the right side in the UT muscle for the SI8 and SI14 groups (F 3,37  = 4.67; p < 0.025) at the 20-minute evaluation. The most vigorous response occurred on the contralateral side because the effects were maintained for 5 minutes after withdrawal (F 3,37  = 4.52; p < 0.025). Both groups showed an increase in the UT muscle strength at the 20-minute evaluation (F 3,37  = 3.41; p < 0.025). The CG and R3 groups did not show any changes. Our data indicate that SI a yang meridian increases the UT muscle response. Copyright © 2016. Published by Elsevier B.V.

Crossed reciprocal inhibition evoked by electrical stimulation of the lamprey spinal cord.

PubMed

Fagerstedt, P; Zelenin, P V; Deliagina, T G; Orlovsky, G N; Grillner, S

2000-09-01

Activation of a motoneuron pool is often accompanied by inhibition of the antagonistic pool through a system of reciprocal inhibition between the two parts of the neuronal network controlling the antagonistic pools. In the present study, we describe the activity of such a system in the isolated spinal cord of the lamprey, when a tonic motor output is evoked by extracellular stimulation (0.5-1 s train of pulses, 20 Hz) of either end of the spinal cord. With two electrodes symmetrically positioned in relation to the midline, stimulation with either of them separately elicited prolonged (1-5 s) ipsilateral ventral root activity. Activity could be abolished by stronger, simultaneously applied, stimulation of the contralateral side of the cord, suggesting that reciprocal inhibition between hemisegments operates when a tonic motor output is generated. Simultaneous stimulation of both sides of the spinal cord with a single electrode with a large tip (300-400 microm in diameter), positioned over the anatomical midline, elicited inconsistent right-side, leftside, or bilateral ventral root responses. A minor displacement (10-20 microm) to the left or right from the midline resulted in activation of ipsilateral motoneurons, whereas the contralateral motoneurons were silent. These findings indicate that a small asymmetry in the excitatory drive to the left and right spinal hemisegments can be further amplified by reciprocal inhibition between the hemisegments. Longitudinal splitting of the spinal cord along the midline resulted in reduced reciprocal inhibition between the hemisegments separated by the lesion. The reduction was proportional to the extent of the split. The inhibition was abolished when the split reached nine segments in length. From these experiments, the longitudinal distribution of the commissural axons responsible for inhibition of contralateral motor output could be estimated.

21 CFR 874.1820 - Surgical nerve stimulator/locator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Surgical nerve stimulator/locator. 874.1820... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1820 Surgical nerve stimulator/locator. (a) Identification. A surgical nerve stimulator/locator is a device that is intended to...

EphB2 guides axons at the midline and is necessary for normal vestibular function

NASA Technical Reports Server (NTRS)

Cowan, C. A.; Yokoyama, N.; Bianchi, L. M.; Henkemeyer, M.; Fritzsch, B.

2000-01-01

Mice lacking the EphB2 receptor tyrosine kinase display a cell-autonomous, strain-specific circling behavior that is associated with vestibular phenotypes. In mutant embryos, the contralateral inner ear efferent growth cones exhibit inappropriate pathway selection at the midline, while in mutant adults, the endolymph-filled lumen of the semicircular canals is severely reduced. EphB2 is expressed in the endolymph-producing dark cells in the inner ear epithelium, and these cells show ultrastructural defects in the mutants. A molecular link to fluid regulation is provided by demonstrating that PDZ domain-containing proteins that bind the C termini of EphB2 and B-ephrins can also recognize the cytoplasmic tails of anion exchangers and aquaporins. This suggests EphB2 may regulate ionic homeostasis and endolymph fluid production through macromolecular associations with membrane channels that transport chloride, bicarbonate, and water.

Interaural attenuation for Sennheiser HDA 200 circumaural earphones.

PubMed

Brännström, K Jonas; Lantz, Johannes

2010-06-01

Interaural attenuation (IA) was evaluated for pure tones (frequency range 125 to 16000 Hz) using Sennheiser HDA 200 circumaural earphones and Telephonics TDH-39P earphones in nine unilaterally deaf subjects. Audiometry was conducted in 1-dB steps using the manual ascending technique in accordance with ISO 8253-1. For all subjects and for all tested frequencies, the lowest IA value for HDA 200 was 42 dB. The present IA values for TDH-39P earphones closely resemble previously reported data. The findings show that the HDA 200 earphones provide more IA than the TDH-39P, especially at lower frequencies (

Three-dimensional analysis of cranial and facial asymmetry after helmet therapy for positional plagiocephaly.

PubMed

Lee, Myung Chul; Hwang, Jin; Kim, Yong Oock; Shim, Kyu Won; Park, Eun Kyung; Lew, Dae Hyun; Yun, In Sik

2015-07-01

Helmet therapy is a non-surgical option for treating positional plagiocephaly, and its effectiveness has been validated by various researches. In addition to cranial flattening and asymmetry, ipsilateral prominence of the mid-face and relative anterior transposition of the ipsilateral ear is also common. Hence, we investigated the impact of helmet therapy on mid-facial asymmetry. Ninety-nine patients diagnosed with positional plagiocephaly and treated by helmet therapy between September 2005 and July 2012 were enrolled. Therapy was initiated at various ages: group I, <6 months (n = 35); group II, 6 months to 1 year (n = 43); group III, >1 year (n = 21). A cranial vault asymmetry index was measured at the levels of the inferior orbital rim (CVAIIOR-MF) and superior orbital rim (CVAISOR-LC) and midway from the superior orbital rim to the vertex (CVAIMID-UC). Anterior transposition of the ipsilateral ear was verified by measuring the distance (D EAR) between the actual position of the ear and its expected position relative to the contralateral ear. All variables were compared before and after helmet therapy and were categorized by age at treatment initiation. CVAIIOR-MF and CVAISOR-LC were lower in all three age groups after helmet therapy, confirming therapeutic efficacy. CVAIMID-UC (upper level cranial asymmetry) and D EAR (mid-facial soft tissue asymmetry) also improved significantly in groups I and II which were younger than 1 year old. In positional plagiocephaly, helmet therapy is effective in correcting both cranial and mid-facial asymmetries. Outcomes were optimal in patients <1 year of age, but older patients also showed some improvement.

Diagnostic utility of the acoustic reflex in predicting hearing in paediatric populations.

PubMed

Pérez-Villa, Yolanda E; Mena-Ramírez, María E; Aguirre, Laura E Chamlati; Mora-Magaña, Ignacio; Gutiérrez-Farfán, Ileana S

2014-01-01

The sensitivity of prediction of acoustic reflex, in determining the level of hearing loss, is especially useful in paediatric populations. It is based on the difference between the pure tone stapedius reflex threshold and contralateral white noise. The white noise threshold was 60 dB and that of pure tone was 80 dB. Our objective was to determine the diagnostic sensitivity of the prediction of the acoustic reflex. We studied children aged <10 years, from October 2011 to May 2012, by measuring the acoustic reflex with white noise and pure tone. We used contrast tests, with X2 and student t-test. Concordance was measured with Kappa. Results were considered significant at P≤.05. Our protocol was approved by Institutional Ethics Committee. Informed consent was obtained from the parents in all cases. Prediction of normal hearing was 0.84 for the right ear and 0.78 in left ear, while for hearing loss of an unspecified grade, it was 0.98 for the right ear and 0.96 in the left ear. Kappa value was 0.7 to 0.6 for the right ear and left ear. The acoustic reflex is of little diagnostic utility in predicting the degree of hearing loss, but it predicts more than 80% of normal hearing. The clinical utility of the reflex is indisputable, as it is an objective method, simple and rapid to use, that can be performed from birth and whose results are independent of the cooperation and willingness of the subject. It is proposed as an obligatory part of hearing screening. Copyright © 2013 Elsevier España, S.L.U. y Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

PI3K, ERK, p38 MAPK and integrins regulate CCR3-mediated secretion of mouse and human eosinophil-associated RNases

PubMed Central

Shamri, Revital; Young, Kristen M.; Weller, Peter F.

2013-01-01

Background Eosinophils have the capacity to secrete varied cytotoxic proteins. Among the proteins are the eosinophil-associated RNases (EARs): the human eosinophil-derived neurotoxin and eosinophilic cationic protein and their murine ortholog EARs, which have been shown to be involved in host defense, tissue remodeling and immunity regulation. However, the signal transduction that regulates EARs secretion in response to physiological stimuli, such as chemokines, has been little studied in human and scarcely in mouse eosinophils, the foremost animal model for eosinophil-associated human diseases. Objective In this study we aimed to understand the signal transduction involved in the secretion of enzymatically active EARs following chemokine stimulation. Methods Fresh mouse and human eosinophils were stimulated with CCL11 and CCL24 and the secretion of enzymatically active EARs was detected using an RNase activity assay. The involvement of signaling factors or integrins was probed using specific inhibitors and blocking antibodies. Adhesion was evaluated by microscopy. Results We found that secretion of mouse EARs in response to CCL11 and CCL24 was Gαi-dependent. Both mouse and human eosinophils required the activation of PI3K, ERK and p38 MAPK. In addition, the adhesion molecules β1 and β2 integrins were found to be crucial for EAR secretion, and we suggest a mechanism in which spreading is obligatory for EAR secretion. Conclusions Collectively, these data suggest a common CCR3-mediated signaling pathway that leads to EAR secretion in both mouse and human eosinophils. These findings are applicable for eosinophil-mediated host defense and eosinophil-associated diseases. PMID:23742707

β1- and β2-adrenergic stimulation-induced electrogenic transport by human endolymphatic sac epithelium and its clinical implications

PubMed Central

Kim, Bo Gyung; Kim, Jin Young; Jung, JinSei; Moon, In Seok; Yoon, Joo-Heon; Choi, Jae Young; Kim, Sung Huhn

2017-01-01

The endolymphatic sac (ES) is a cystic structure of the inner ear connected to the cochlea and vestibule, which plays a role in regulating ion homeostasis in inner ear fluid. Disruption of ion homeostasis can cause inner ear disorders with hearing loss and dizziness, such as Meniere’s disease. Herein, we found, for the first time, functional evidence for the involvement of β1- and β2-adrenergic receptors in apical electrogenic ion transport by human ES epithelium by using electrophysiological/pharmacological and molecular biological methods, which were dependent on K+ and Cl− ion transport. The apical electrogenic transport was absent or very weak in ES epithelia of patients with Meniere’s disease. These results suggested that adrenergic stimulation via β1- and β2-adrenergic receptors in the human ES was involved in regulation of inner ear fluid ion homeostasis and impairment of this response could be a pathological mechanism of Meniere’s disease. PMID:28165045

Cooperative processing in primary somatosensory cortex and posterior parietal cortex during tactile working memory.

PubMed

Ku, Yixuan; Zhao, Di; Bodner, Mark; Zhou, Yong-Di

2015-08-01

In the present study, causal roles of both the primary somatosensory cortex (SI) and the posterior parietal cortex (PPC) were investigated in a tactile unimodal working memory (WM) task. Individual magnetic resonance imaging-based single-pulse transcranial magnetic stimulation (spTMS) was applied, respectively, to the left SI (ipsilateral to tactile stimuli), right SI (contralateral to tactile stimuli) and right PPC (contralateral to tactile stimuli), while human participants were performing a tactile-tactile unimodal delayed matching-to-sample task. The time points of spTMS were 300, 600 and 900 ms after the onset of the tactile sample stimulus (duration: 200 ms). Compared with ipsilateral SI, application of spTMS over either contralateral SI or contralateral PPC at those time points significantly impaired the accuracy of task performance. Meanwhile, the deterioration in accuracy did not vary with the stimulating time points. Together, these results indicate that the tactile information is processed cooperatively by SI and PPC in the same hemisphere, starting from the early delay of the tactile unimodal WM task. This pattern of processing of tactile information is different from the pattern in tactile-visual cross-modal WM. In a tactile-visual cross-modal WM task, SI and PPC contribute to the processing sequentially, suggesting a process of sensory information transfer during the early delay between modalities. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Bilateral responses of upper limb muscles to transcranial magnetic stimulation in human subjects.

PubMed

Bawa, P; Hamm, J D; Dhillon, P; Gross, P A

2004-10-01

Anatomical and behavioural work on primates has shown bilateral innervation of axial and proximal limb muscles, and contralateral control of distal limb muscles. The following study examined if a clear boundary exists between the distal and proximal upper limb muscles that are controlled contralaterally or bilaterally. The right motor cortical area representing the upper limb was stimulated, while surface EMG was recorded bilaterally from various upper limb muscles during rest and phasic voluntary contractions. Peak-to-peak amplitude of motor evoked potential (MEP) was measured for each muscle on both sides. The ratio R = (ipsilateral MEP: contralateral MEP) was calculated for seven pairs of muscles. For each of the seven pairs, R was less than 1.0, implying that for each muscle and subject, the contralateral control is stronger. The boundary where R changed from almost zero to a clearly measurable magnitude depended on the subject. Ipsilateral MEPs from trapezius and pectoralis could be recorded with a small background contraction from almost all subjects; on the other hand, in deltoid and biceps brachii, ipsilateral MEPs were observed only with bimanual phasic contractions. The forearm and hand muscles, in general, did not show any ipsilateral MEPs. Major differences between subjects lay in the presence or the absence of ipsilateral MEPs in biceps brachii and deltoid, without defining a sharp boundary between proximal and distal muscles.

Tinnitus treatment with precise and optimal electric stimulation: opportunities and challenges.

PubMed

Zeng, Fan-Gang; Djalilian, Hamid; Lin, Harrison

2015-10-01

Electric stimulation is a potent means of neuromodulation that has been used to restore hearing and minimize tremor, but its application on tinnitus symptoms has been limited. We examine recent evidence to identify the knowledge gaps in the use of electric stimulation for tinnitus treatment. Recent studies using electric stimulation to suppress tinnitus in humans are categorized according to their points of attacks. First, noninvasive, direct current stimulation uses an active electrode in the ear canal, tympanic membrane, or temporal scalp. Second, inner ear stimulation uses charge-balanced biphasic stimulation by placing an active electrode on the promontory or round window, or a cochlear implant array in the cochlea. Third, intraneural implants can provide targeted stimulation of specific sites along the auditory pathway. Although these studies demonstrated some success in tinnitus suppression, none established a link between tinnitus suppression efficacy and tinnitus-generating mechanisms. Electric stimulation provides a unique opportunity to suppress tinnitus. Challenges include matching electric stimulation sites and patterns to tinnitus locus and type, meeting the oftentimes-contradictory demands between tinnitus suppression and other indications, such as speech understanding, and justifying the costs and risks of electric stimulation for tinnitus symptoms.

Tinnitus Treatment with Precise and Optimal Electric Stimulation: Opportunities and Challenges

PubMed Central

Zeng, Fan-Gang; Djalilian, Hamid; Lin, Harrison

2015-01-01

Purpose of review Electric stimulation is a potent means of neuromodulation that has been used to restore hearing and minimize tremor, but its application on tinnitus symptoms has been limited. We examine recent evidence to identify the knowledge gaps in the use of electric stimulation for tinnitus treatment. Recent findings Recent studies using electric stimulation to suppress tinnitus in humans are categorized according to their points of attacks. First, non-invasive, direct-current stimulation uses an active electrode in the ear canal, tympanic membrane or temporal scalp. Second, inner ear stimulation uses charge-balanced biphasic stimulation by placing an active electrode on the promontory or round window, or a cochlear implant array in the cochlea. Third, intraneural implants can provide targeted stimulation of specific sites along the auditory pathway. Although these studies demonstrated some success in tinnitus suppression, none established a link between tinnitus suppression efficacy and tinnitus-generating mechanisms. Summary Electric stimulation provides a unique opportunity to suppress tinnitus. Challenges include matching electric stimulation sites and patterns to tinnitus locus and type, meeting the oftentimes-contradictory demands between tinnitus suppression and other indications, such as speech understanding, and justifying the costs and risks of electric stimulation for tinnitus symptoms. PMID:26208122

Is there a best side for cochlear implants in post-lingual patients?

PubMed

Amaral, Maria Stella Arantes do; Damico, Thiago A; Gonçales, Alina S; Reis, Ana C M B; Isaac, Myriam de Lima; Massuda, Eduardo T; Hyppolito, Miguel Angelo

2017-07-29

Cochlear Implant is a sensory prosthesis capable of restoring hearing in patients with severe or profound bilateral sensorineural hearing loss. To evaluate if there is a better side to be implanted in post-lingual patients. Retrospective longitudinal study. Participants were 40 subjects, of both sex, mean age of 47 years, with post-lingual hearing loss, users of unilateral cochlear implant for more than 12 months and less than 24 months, with asymmetric auditor reserve between the ears (difference of 10dBNA, In at least one of the frequencies with a response, between the ears), divided into two groups. Group A was composed of individuals with cochlear implant in the ear with better auditory reserve and Group B with auditory reserve lower in relation to the contralateral side. There was no statistical difference for the tonal auditory threshold before and after cochlear implant. A better speech perception in pre-cochlear implant tests was present in B (20%), but the final results are similar in both groups. The cochlear implant in the ear with the worst auditory residue favors a bimodal hearing, which would allow the binaural summation, without compromising the improvement of the audiometric threshold and the speech perception. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Wideband acoustic reflex test in a test battery to predict middle-ear dysfunction

PubMed Central

Keefe, Douglas H.; Fitzpatrick, Denis; Liu, Yi-Wen; Sanford, Chris A.; Gorga, Michael P.

2013-01-01

A wideband (WB) aural acoustical test battery of middle-ear status, including acoustic-reflex thresholds (ARTs) and acoustic-transfer functions (ATFs, i.e., absorbance and admittance) was hypothesized to be more accurate than 1-kHz tympanometry in classifying ears that pass or refer on a newborn hearing screening (NHS) protocol based on otoacoustic emissions. Assessment of middle-ear status may improve NHS programs by identifying conductive dysfunction and cases in which auditory neuropathy exists. Ipsilateral ARTs were assessed with a stimulus including four broadband-noise or tonal activator pulses alternating with five clicks presented before, between and after the pulses. The reflex shift was defined as the difference between final and initial click responses. ARTs were measured using maximum likelihood both at low frequencies (0.8–2.8 kHz) and high (2.8–8 kHz). The median low-frequency ART was elevated by 24 dB in NHS refers compared to passes. An optimal combination of ATF and ART tests performed better than either test alone in predicting NHS outcomes, and WB tests performed better than 1-kHz tympanometry. Medial olivocochlear efferent shifts in cochlear function may influence ARs, but their presence would also be consistent with normal conductive function. Baseline clinical and WB ARTs were also compared in ipsilateral and contralateral measurements in adults. PMID:19772907

Non-Invasive Brain Stimulation to Enhance Post-Stroke Recovery.

PubMed

Kubis, Nathalie

2016-01-01

Brain plasticity after stroke remains poorly understood. Patients may improve spontaneously within the first 3 months and then more slowly in the coming year. The first day, decreased edema and reperfusion of the ischemic penumbra may possibly account for these phenomena, but the improvement during the next weeks suggests plasticity phenomena and cortical reorganization of the brain ischemic areas and of more remote areas. Indeed, the injured ischemic motor cortex has a reduced cortical excitability at the acute phase and a suspension of the topographic representation of affected muscles, whereas the contralateral motor cortex has an increased excitability and an enlarged somatomotor representation; furthermore, contralateral cortex exerts a transcallosal interhemispheric inhibition on the ischemic cortex. This results from the imbalance of the physiological reciprocal interhemispheric inhibition of each hemisphere on the other, contributing to worsening of neurological deficit. Cortical excitability is measurable through transcranial magnetic stimulation (TMS) and prognosis has been established according to the presence of motor evoked potentials (MEP) at the acute phase of stroke, which is predictive of better recovery. Conversely, the lack of response to early stimulation is associated with a poor functional outcome. Non-invasive stimulation techniques such as repetitive TMS (rTMS) or transcranial direct current stimulation (tDCS) have the potential to modulate brain cortical excitability with long lasting effects. In the setting of cerebrovascular disease, around 1000 stroke subjects have been included in placebo-controlled trials so far, most often with an objective of promoting motor recovery of the upper limb. High frequency repetitive stimulation (>3 Hz) rTMS, aiming to increase excitability of the ischemic cortex, or low frequency repetitive stimulation (≤1 Hz), aiming to reduce excitability of the contralateral homonymous cortex, or combined therapies, have shown various effects on the functional disability score and neurological scales of treated patients and on the duration of the treatment. We review here the patients' characteristics and parameters of stimulation that could predict a good response, as well as safety issues. At last, we review what we have learnt from experimental studies and discuss potential directions to conduct future studies.

Non-Invasive Brain Stimulation to Enhance Post-Stroke Recovery

PubMed Central

Kubis, Nathalie

2016-01-01

Brain plasticity after stroke remains poorly understood. Patients may improve spontaneously within the first 3 months and then more slowly in the coming year. The first day, decreased edema and reperfusion of the ischemic penumbra may possibly account for these phenomena, but the improvement during the next weeks suggests plasticity phenomena and cortical reorganization of the brain ischemic areas and of more remote areas. Indeed, the injured ischemic motor cortex has a reduced cortical excitability at the acute phase and a suspension of the topographic representation of affected muscles, whereas the contralateral motor cortex has an increased excitability and an enlarged somatomotor representation; furthermore, contralateral cortex exerts a transcallosal interhemispheric inhibition on the ischemic cortex. This results from the imbalance of the physiological reciprocal interhemispheric inhibition of each hemisphere on the other, contributing to worsening of neurological deficit. Cortical excitability is measurable through transcranial magnetic stimulation (TMS) and prognosis has been established according to the presence of motor evoked potentials (MEP) at the acute phase of stroke, which is predictive of better recovery. Conversely, the lack of response to early stimulation is associated with a poor functional outcome. Non-invasive stimulation techniques such as repetitive TMS (rTMS) or transcranial direct current stimulation (tDCS) have the potential to modulate brain cortical excitability with long lasting effects. In the setting of cerebrovascular disease, around 1000 stroke subjects have been included in placebo-controlled trials so far, most often with an objective of promoting motor recovery of the upper limb. High frequency repetitive stimulation (>3 Hz) rTMS, aiming to increase excitability of the ischemic cortex, or low frequency repetitive stimulation (≤1 Hz), aiming to reduce excitability of the contralateral homonymous cortex, or combined therapies, have shown various effects on the functional disability score and neurological scales of treated patients and on the duration of the treatment. We review here the patients’ characteristics and parameters of stimulation that could predict a good response, as well as safety issues. At last, we review what we have learnt from experimental studies and discuss potential directions to conduct future studies. PMID:27512367

Missing links in some curious auditory phenomena: a tale from the middle ear.

PubMed

Carpenter, Michelle S; Cacace, Anthony T; Mahoney, Marty J

2012-02-01

Broadband middle ear power reflectance (BMEPR) is an emerging noninvasive electroacoustic measure that evaluates transmission/reflection properties of the middle ear in high resolution. It is applicable over the entire age continuum and is rapid to perform. However, it remains to be determined if BMEPR is just an incremental step in the evolution of middle ear assessment or a major advance in the way middle ear function can be evaluated. To evaluate effects of age, gender, ear, and frequency on BMEPR measurements in adults without a history of middle ear disease and to assess whether these factors require consideration in test development; to review how these data may influence active physiologic process within the inner ear; to consider how they reconcile with previously published results; and to suggest applications for future research. Prospective, cross-sectional, multivariate analysis to evaluate the effects of age, gender, ear, and frequency on BMEPR in humans without a history of middle ear disease and no air-bone gaps exceeding 10 dB for any frequency. Fifty-six adults in two age groups (Group 1: 18-25 yr, n = 28; Group 2: ≥50 and <66 yr, n = 28). Each age group was stratified by ear and gender in a balanced design. Pure tone air conduction and bone-conduction audiometry was conducted in a commercial sound booth, using a clinical audiometer with standard earphones enclosed in supra-aural ear cushions, and a standard bone-conduction oscillator and headband to evaluate for air-bone gaps. Broadband middle ear power reflectance was measured using a calibrated, commercially available computer-controlled system that incorporated a high quality probe assembly to transduce stimuli and record acoustic responses from the ear canal. Data were analyzed with a four-way (2 × 2 × 2 × 16) repeated measures analysis-of-variance (ANOVA) to evaluate the effects of age group (young vs. old), gender (male vs. female), ear (left vs. right), and frequency (258 to 5040 Hz) on BMEPR. The ANOVA revealed a significant main effect of frequency. There were also gender × ear, gender × frequency, and age × gender × ear interactions. The three-way, age × gender × ear interaction captured the essence of results and revealed lowest power reflectance values in younger females and for right ears. This trend partially reversed in the older age group where higher power reflectance values were observed only in right ears of older females. The significant effects of age, gender, ear, and frequency on BMEPR parallel ear- and gender-related differences in hearing sensitivity, ear, and gender differences in the prevalence of spontaneous otoacoustic emissions (OAEs), gender differences in the magnitude of transient evoked OAEs, and ear differences in transient evoked contralateral OAE suppression effects reported in the literature. While original discussions of these aforementioned effects focused primarily on endocochlear and olivocochlear mechanisms, the BMEPR measurements reported herein suggest that middle ear transmission characteristics may also play a role. American Academy of Audiology.

Contralateral routing of signals disrupts monaural level and spectral cues to sound localisation on the horizontal plane.

PubMed

Pedley, Adam J; Kitterick, Pádraig T

2017-09-01

Contra-lateral routing of signals (CROS) devices re-route sound between the deaf and hearing ears of unilaterally-deaf individuals. This rerouting would be expected to disrupt access to monaural level cues that can support monaural localisation in the horizontal plane. However, such a detrimental effect has not been confirmed by clinical studies of CROS use. The present study aimed to exercise strict experimental control over the availability of monaural cues to localisation in the horizontal plane and the fitting of the CROS device to assess whether signal routing can impair the ability to locate sources of sound and, if so, whether CROS selectively disrupts monaural level or spectral cues to horizontal location, or both. Unilateral deafness and CROS device use were simulated in twelve normal hearing participants. Monaural recordings of broadband white noise presented from three spatial locations (-60°, 0°, and +60°) were made in the ear canal of a model listener using a probe microphone with and without a CROS device. The recordings were presented to participants via an insert earphone placed in their right ear. The recordings were processed to disrupt either monaural level or spectral cues to horizontal sound location by roving presentation level or the energy across adjacent frequency bands, respectively. Localisation ability was assessed using a three-alternative forced-choice spatial discrimination task. Participants localised above chance levels in all conditions. Spatial discrimination accuracy was poorer when participants only had access to monaural spectral cues compared to when monaural level cues were available. CROS use impaired localisation significantly regardless of whether level or spectral cues were available. For both cues, signal re-routing had a detrimental effect on the ability to localise sounds originating from the side of the deaf ear (-60°). CROS use also impaired the ability to use level cues to localise sounds originating from straight ahead (0°). The re-routing of sounds can restrict access to the monaural cues that provide a basis for determining sound location in the horizontal plane. Perhaps encouragingly, the results suggest that both monaural level and spectral cues may not be disrupted entirely by signal re-routing and that it may still be possible to reliably identify sounds originating on the hearing side. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Dorsolateral prefrontal cortex bridges bilateral primary somatosensory cortices during cross-modal working memory.

PubMed

Zhao, Di; Ku, Yixuan

2018-05-01

Neural activity in the dorsolateral prefrontal cortex (DLPFC) has been suggested to integrate information from distinct sensory areas. However, how the DLPFC interacts with the bilateral primary somatosensory cortices (SIs) in tactile-visual cross-modal working memory has not yet been established. In the present study, we applied single-pulse transcranial magnetic stimulation (sp-TMS) over the contralateral DLPFC and bilateral SIs of human participants at various time points, while they performed a tactile-visual delayed matching-to-sample task with a 2-second delay. sp-TMS over the contralateral DLPFC or the contralateral SI at either an sensory encoding stage [i.e. 100 ms after the onset of a vibrotactile sample stimulus (200-ms duration)] or an early maintenance stage (i.e. 300 ms after the onset), significantly impaired the accuracy of task performance; sp-TMS over the contralateral DLPFC or the ipsilateral SI at a late maintenance stage (1600 ms and 1900 ms) also significantly disrupted the performance. Furthermore, at 300 ms after the onset of the vibrotactile sample stimulus, there was a significant correlation between the deteriorating effects of sp-TMS over the contralateral SI and the contralateral DLPFC. These results imply that the DLPFC and the bilateral SIs play causal roles at distinctive stages during cross-modal working memory, while the contralateral DLPFC communicates with the contralateral SI in the early delay, and cooperates with the ipsilateral SI in the late delay. Copyright © 2018 Elsevier B.V. All rights reserved.

How do tympanic-membrane perforations affect human middle-ear sound transmission?

PubMed

Voss, S E; Rosowski, J J; Merchant, S N; Peake, W T

2001-01-01

Although tympanic-membrane (TM) perforations are common sequelae of middle-ear disease, the hearing losses they cause have not been accurately determined, largely because additional pathological conditions occur in these ears. Our measurements of acoustic transmission before and after making controlled perforations in cadaver ears show that perforations cause frequency-dependent loss that: (1) is largest at low frequencies; (2) increases as perforation size increases; and (3) does not depend on perforation location. The dominant loss mechanism is the reduction in sound-pressure difference across the TM. Measurements of middle-ear air-space sound pressures show that transmission via direct acoustic stimulation of the oval and round windows is generally negligible. A quantitative model predicts the influence of middle-ear air-space volume on loss; with larger volumes, loss is smaller.

Pain Experience is Somatotopically Organized and Overlaps with Pain Anticipation in the Human Cerebellum.

PubMed

Michelle Welman, F H S; Smit, Albertine E; Jongen, Joost L M; Tibboel, Dick; van der Geest, Jos N; Holstege, Jan C

2018-02-26

Many fMRI studies have shown activity in the cerebellum after peripheral nociceptive stimulation. We investigated whether the areas in the cerebellum that were activated after nociceptive thumb stimulation were separate from those after nociceptive toe stimulation. In an additional experiment, we investigated the same for the anticipation of a nociceptive stimulation on the thumb or toe. For his purpose, we used fMRI after an electrical stimulation of the thumb and toe in 19 adult healthy volunteers. Following nociceptive stimulation, different areas were activated by stimulation on the thumb (lobule VI ipsilaterally and Crus II mainly contralaterally) and toe (lobules VIII-IX and IV-V bilaterally and lobule VI contralaterally), i.e., were somatotopically organized. Cerebellar areas innervated non-somatotopically by both toe and thumb stimulation were the posterior vermis and Crus I, bilaterally. In the anticipation experiment, similar results were found. However, here, the somatotopically activated areas were relatively small for thumb and negligible for toe stimulation, while the largest area was innervated non-somatotopically and consisted mainly of Crus I and lobule VI bilaterally. These findings indicate that nociceptive stimulation and anticipation of nociceptive stimulation are at least partly processed by the same areas in the cerebellum. This was confirmed by an additional conjunction analysis. Based on our findings, we hypothesize that input that is organized in a somatotopical manner reflects direct input from the spinal cord, while non-somatotopically activated parts of the cerebellum receive their information indirectly through cortical and subcortical connections, possibly involved in processing contextual emotional states, like the expectation of pain.

Functional evaluation of a cell replacement therapy in the inner ear

PubMed Central

Hu, Zhengqing; Ulfendahl, Mats; Prieskorn, Diane M.; Olivius, N. Petri; Miller, Josef M.

2015-01-01

Hypothesis Cell replacement therapy in the inner ear will contribute to the functional recovery of hearing loss. Background Cell replacement therapy is a potentially powerful approach to replace degenerated or severely damaged spiral ganglion neurons. This study aimed at stimulating the neurite outgrowth of the implanted neurons and enhancing the potential therapeutic of inner ear cell implants. Methods Chronic electrical stimulation (CES) and exogenous neurotrophic growth factor (NGF) were applied to 46 guinea pigs transplanted with embryonic dorsal root ganglion (DRG) neurons four days post deafening. The animals were evaluated with the electrically-evoked auditory brain stem responses (EABRs) at experimental day 7, 11, 17, 24, 31. The animals were euthanized at day 31 and the inner ears were dissected out for immunohistochemistry investigation. Results Implanted DRG cells, identified by EGFP fluorescence and a neuronal marker, were found close to Rosenthal's canal in the adult inner ear for up to four weeks following transplantation. Extensive neurite projections clearly, greater than in non-treated animals, were observed to penetrate the bony modiolus and reach the spiral ganglion region in animals supplied with CES and/or NGF. There was, however, no significant difference in the thresholds of EABRs between DRG-transplanted-animals supplied with CES and/or NGF and DRG-transplanted animals without CES or NGF supplement. Conclusions The results suggest that CES and/or NGF can stimulate neurite outgrowth from implanted neurons, although based on EABR measurement these interventions did not induce functional connections to the central auditory pathway. Additional time or novel approaches may enhance functional responsiveness of implanted cells in the adult cochlea. PMID:19395986

Binaural Interaction Effects of 30-50 Hz Auditory Steady State Responses.

PubMed

Gransier, Robin; van Wieringen, Astrid; Wouters, Jan

Auditory stimuli modulated by modulation frequencies within the 30 to 50 Hz region evoke auditory steady state responses (ASSRs) with high signal to noise ratios in adults, and can be used to determine the frequency-specific hearing thresholds of adults who are unable to give behavioral feedback reliably. To measure ASSRs as efficiently as possible a multiple stimulus paradigm can be used, stimulating both ears simultaneously. The response strength of 30 to 50Hz ASSRs is, however, affected when both ears are stimulated simultaneously. The aim of the present study is to gain insight in the measurement efficiency of 30 to 50 Hz ASSRs evoked with a 2-ear stimulation paradigm, by systematically investigating the binaural interaction effects of 30 to 50 Hz ASSRs in normal-hearing adults. ASSRs were obtained with a 64-channel EEG system in 23 normal-hearing adults. All participants participated in one diotic, multiple dichotic, and multiple monaural conditions. Stimuli consisted of a modulated one-octave noise band, centered at 1 kHz, and presented at 70 dB SPL. The diotic condition contained 40 Hz modulated stimuli presented to both ears. In the dichotic conditions, the modulation frequency of the left ear stimulus was kept constant at 40 Hz, while the stimulus at the right ear was either the unmodulated or modulated carrier. In case of the modulated carrier, the modulation frequency varied between 30 and 50 Hz in steps of 2 Hz across conditions. The monaural conditions consisted of all stimuli included in the diotic and dichotic conditions. Modulation frequencies ≥36 Hz resulted in prominent ASSRs in all participants for the monaural conditions. A significant enhancement effect was observed (average: ~3 dB) in the diotic condition, whereas a significant reduction effect was observed in the dichotic conditions. There was no distinct effect of the temporal characteristics of the stimuli on the amount of reduction. The attenuation was in 33% of the cases >3 dB for ASSRs evoked with modulation frequencies ≥40 Hz and 50% for ASSRs evoked with modulation frequencies ≤36 Hz. Binaural interaction effects as observed in the diotic condition are similar to the binaural interaction effects of middle latency responses as reported in the literature, suggesting that these responses share a same underlying mechanism. Our data also indicated that 30 to 50 Hz ASSRs are attenuated when presented dichotically and that this attenuation is independent of the stimulus characteristics as used in the present study. These findings are important as they give insight in how binaural interaction affects the measurement efficiency. The 2-ear stimulation paradigm of the present study was, for the most optimal modulation frequencies (i.e., ≥40 Hz), more efficient than a 1-ear sequential stimulation paradigm in 66% of the cases.

The efficiency of simultaneous binaural ocular vestibular evoked myogenic potentials: a comparative study with monaural acoustic stimulation in healthy subjects.

PubMed

Kim, Min-Beom; Ban, Jae Ho

2012-12-01

To evaluate the test-retest reliability and convenience of simultaneous binaural acoustic-evoked ocular vestibular evoked myogenic potentials (oVEMP). Thirteen healthy subjects with no history of ear diseases participated in this study. All subjects underwent oVEMP test with both separated monaural acoustic stimulation and simultaneous binaural acoustic stimulation. For evaluating test-retest reliability, three repetitive sessions were performed in each ear for calculating the intraclass correlation coefficient (ICC) for both monaural and binaural tests. We analyzed data from the biphasic n1-p1 complex, such as latency of peak, inter-peak amplitude, and asymmetric ratio of amplitude in both ears. Finally, we checked the total time required to complete each test for evaluating test convenience. No significant difference was observed in amplitude and asymmetric ratio in comparison between monaural and binaural oVEMP. However, latency was slightly delayed in binaural oVEMP. In test-retest reliability analysis, binaural oVEMP showed excellent ICC values ranging from 0.68 to 0.98 in latency, asymmetric ratio, and inter-peak amplitude. Additionally, the test time was shorter in binaural than monaural oVEMP. oVEMP elicited from binaural acoustic stimulation yields similar satisfactory results as monaural stimulation. Further, excellent test-retest reliability and shorter test time were achieved in binaural than in monaural oVEMP.

The clinical analysis of bilateral successive sudden sensorineural hearing loss.

PubMed

Wang, Yaowen; Zhang, Litao; Zhang, Jianhua; Zhang, Xuqun; Zhang, Weimin; Chen, Xing; Tang, Shixiong

2016-11-01

The objective of this study is to investigate the clinical characteristics of successive bilateral sudden sensorineural hearing loss (SSNHL) with an interval of more than 1 year to aid the evaluation and management of successive bilateral SSNHL (BSSNHL). 14 successive BSSNHL patients and 118 unilateral SSNHL patients with severe and profound hearing loss were reviewed retrospectively. Information about successive BSSNHL was collected included demographics, the intervals between the attacks of bilateral ears, the past medical history, inducing factors, accompanying symptoms, pure-tone tests, blood tests, b-ultrasound examinations of vertebral artery and carotid artery, and medical interventions. And the comparison of improvement rate was made between successive BSSNHL and unilateral SSNHL. SPSS 15.0 was used to analyze the data. In successive BSSNHL, there were six males and eight females; the average aged was 49.86 ± 15.45 years (20-73 years). The interval of the two attacks was 11.43 ± 12.07 years (1-50 years) on average. The onset of treatment was 18.86 ± 12.71 days. Tinnitus was seen in 100 % of the patients, followed by vertigo in 42.85 %, and ear fullness in 21.43 %. 3 of 14 patients described obvious inducing factor: tiredness. Five patients (35.71 %) had hypertension histories, three (21.43 %) had diabetes histories, two (14.29 %) had surgery histories, one (7.14 %) was with depression history, one (7.14 %) was with coronary heart disease history. 30 % (3/10) patients were with atherosclerotic plaque in carotid artery. 4 (28.57 %) patients were with high blood sugar. 8 patients (57.14 %) were with high blood lipids. Thyroid function tests were positive in 27.27 % (3/11) patients. No abnormality was found in antinuclear antibodies titer. The percentage of profound and severe hearing loss were 71.43 and 78.57 % in the recently affected ear and contralateral ear separately. The PTAs of the recently affected ear were 77.14 ± 27.12 dB before treatment and 68.84 ± 22.32 dB after treatment, the improvement rate was 28.57 %. No improvement was found in the contralateral ears. In unilateral SSNHL, the average age was 42.47 ± 14.18 years. The onset of treatment was 18.08 ± 15.84 days. The improvement rate was 57.63 %, which was much higher than that of successive BSSNHL. There was no difference in age and time of onset of treatment between successive BSSNHL and unilateral SSNHL (p > 0.05). Successive BSSNHL is rare, the hearing impairment is severe, and the outcome of treatment is poorer. It may have a completely different profile compared with the simultaneous BSSNHL and unilateral SSNHL.

Effects of short and prolonged transcutaneous vagus nerve stimulation on heart rate variability in healthy subjects.

PubMed

De Couck, M; Cserjesi, R; Caers, R; Zijlstra, W P; Widjaja, D; Wolf, N; Luminet, O; Ellrich, J; Gidron, Y

2017-03-01

The vagus nerve is strategically located in the body, and has multiple homeostatic and health-promoting effects. Low vagal activity predicts onset and progression of diseases. These are the reasons to activate this nerve. This study examined the effects of transcutaneous vagus nerve stimulation (t-VNS) on a main index of vagal activity, namely heart rate variability (HRV). In Study 1, we compared short (10min) left versus right ear t-VNS versus sham (no stimulation) in a within-subjects experimental design. Results revealed significant increases in only one HRV parameter (standard deviation of the RR intervals (SDNN)) following right-ear t-VNS. Study 2 examined the prolonged effects of t-VNS (1h) in the right ear. Compared to baseline, right-t-VNS significantly increased the LF and LF/HF components of HRV, and SDNN in women, but not in men. These results show limited effects of t-VNS on HRV, and are discussed in light of neuroanatomical and statistical considerations and future directions are proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

Further studies on the effects of magnetic resonance imaging fields on middle ear implants.

PubMed

Applebaum, E L; Valvassori, G E

1990-10-01

We investigated the effects of magnetic resonance imaging (MRI) fields on 21 stapedectomy prostheses and other middle ear implants and two different receiver-stimulator modules from 22-channel cochlear implants. None of the middle ear implants was displaced by the magnetic field, except for one platinum-stainless steel stapedectomy piston. Magnetism was not induced in any of the middle ear implants subjected to prolonged exposure in the MRI scanner. We conclude that MRI could pose a hazard to patients who have had stapedectomy using certain platinum-stainless steel piston prostheses and to patients with cochlear implants. Magnetic resonance imaging should pose no hazard to patients who have had the other middle ear implants reported on in this and our previous investigation.

Cortical inhibition effect in musicians and non-musicians using P300 with and without contralateral stimulation.

PubMed

Rabelo, Camila Maia; Neves-Lobo, Ivone Ferreira; Rocha-Muniz, Caroline Nunes; Ubiali, Thalita; Schochat, Eliane

2015-01-01

Musicians have more robust and efficient neural responses in the cortical and sub-cortical regions, demonstrating that musical experience benefits the processing of both non-linguistic and linguistic stimuli. This study aimed to verify P300's latency and amplitude behavioral using contralateral stimulation in musicians and non-musicians. This was a case-control study. Subjects were divided in two groups: musicians, comprising 30 professional musicians, and non-musicians, comprising 25 subjects without musical experience. The present study showed that the musicians had lower latencies and higher amplitudes than the non-musicians in the P300 without contralateral noise. For the P300 amplitude values, the difference between groups persisted, and the musicians presented significantly higher amplitude values compared with the non-musicians; additionally, the analysis of the noise effect on the P300 response showed that the latency values were significantly increased in the musicians. The central auditory nervous system of musicians presents peculiar characteristics of electrophysiological responses probably due to the plasticity imposed by musical practice. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Evidence for a bipolar change in distortion product otoacoustic emissions during contralateral acoustic stimulation in humans

NASA Astrophysics Data System (ADS)

Müller, Jörg; Janssen, Thomas; Heppelmann, Guido; Wagner, Wolfgang

2005-12-01

The aim of this study was to investigate the activity of the medial olivocochlear (MOC) efferents during contralateral (CAS) and ipsilateral acoustic stimulation (IAS) by recording distortion product otoacoustic emission (DPOAE) suppression and DPOAE adaptation in humans. The main question was: do large bipolar changes in DPOAE level (transition from enhancement to suppression) also occur in humans when changing the primary tone level within a small range as described by Maison and Liberman for guinea pigs [J. Neurosci. 20, 4701-4707 (2000)]? In the present study, large bipolar changes in DPOAE level (14 dB on average across subjects) were found during CAS predominantly at frequencies where dips in the DPOAE fine structure occurred. Thus, effects of the second DPOAE source might be responsible for the observed bipolar effect. In contrast, comparable effects were not found during IAS as was reported in guinea pigs. Reproducibility of CAS DPOAEs was better than that for IAS DPOAEs. Thus, contralateral DPOAE suppression is suggested to be superior to ipsilateral DPOAE adaptation with regard to measuring the MOC reflex strength and for evaluating the vulnerability of the cochlea to acoustic overexposure in a clinical context.

Serving Deaf Students Who Have Cochlear Implants. PEPNet Tipsheet

ERIC Educational Resources Information Center

Searls, J. Matt, Comp.

2010-01-01

Cochlear implants (CIs) are complex electronic devices surgically implanted under the skin behind the ear. These devices utilize electrodes placed in the inner ear (the cochlea) to stimulate the auditory nerve of individuals with significant permanent hearing loss. Cochlear implants may not be suitable for everyone. They are designed to provide…

SUNA and red ear syndrome: a new association and pathophysiological considerations.

PubMed

Lambru, Giorgio; Bakar, Norazah Abu; Matharu, Manjit

2013-04-08

Red ear syndrome (RES) is characterised by attacks of unilateral or bilateral burning ear pain associated with erythema. Primary and secondary forms have been described. Primary RES appears to have a frequent association with primary headaches especially migraine. Here, we describe the case of a woman with short-lasting unilateral neuralgiform attacks with cranial autonomic symptoms (SUNA) and recurrent episodes of ipsilateral red ear triggerable by cutaneous stimulation. Lamotrigine was beneficial for her SUNA but not for the RES. Both these disorders are extremely rare therefore their coexistence in the same individual may suggest similar pathophysiological mechanisms rather than a chance association.

Transcanal endoscopic ear surgery for perilymphatic fistula after electric acoustic stimulation.

PubMed

Omichi, Ryotaro; Kariya, Shin; Maeda, Yukihide; Nishizaki, Kazunori

2018-06-01

Transcanal endoscopic ear surgery (TEES) will become a very useful therapeutic option. A perilymphatic fistula (PLF) is defined as sudden sensorineural hearing loss and/or vertigo caused by leakage of the perilymph through a fistula from the oval window and/or round window. We report a case of PLF after electric acoustic stimulation (EAS), a kind of cochlear implant, successfully treated by TEES. A 38-year-old man presented to our hospital with vertigo and hearing loss (HL). His vertigo was induced by Valsalva maneuvers. Eight months ago, he underwent EAS for his right ear for congenital sensorineural HL. Although he maintained his hearing level after EAS, his pure tone audiogram this time showed deterioration of hearing at low frequencies in his right ear. A diagnosis of right PLF was made. After confirming the non-effectiveness of oral prednisolone treatment, PLF repair surgery to patch the oval and round windows by TEES was performed. His vertigo did not recur after the surgery. To the best of our knowledge, this is the first report of PLF repair surgery by TEES without a microscope. The wide-field view of the middle ear by TEES was useful to prevent electrode damage in a PLF patient with a cochlear implant. Copyright © 2017 Elsevier B.V. All rights reserved.

Limits on normal cochlear 'third' windows provided by previous investigations of additional sound paths into and out of the cat inner ear.

PubMed

Rosowski, John J; Bowers, Peter; Nakajima, Hideko H

2018-03-01

While most models of cochlear function assume the presence of only two windows into the mammalian cochlea (the oval and round windows), a position that is generally supported by several lines of data, there is evidence for additional sound paths into and out of the inner ear in normal mammals. In this report we review the existing evidence for and against the 'two-window' hypothesis. We then determine how existing data and inner-ear anatomy restrict transmission of sound through these additional sound pathways in cat by utilizing a well-tested model of the cat inner ear, together with anatomical descriptions of the cat cochlear and vestibular aqueducts (potential additional windows to the cochlea). We conclude: (1) The existing data place limits on the size of the cochlear and vestibular aqueducts in cat and are consistent with small volume-velocities through these ducts during ossicular stimulation of the cochlea, (2) the predicted volume velocities produced by aqueducts with diameters half the size of the bony diameters match the functional data within ±10 dB, and (3) these additional volume velocity paths contribute to the inner ear's response to non-acoustic stimulation and conductive pathology. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of nitric oxide synthase inhibitor on increase in nasal mucosal blood flow induced by sensory and parasympathetic nerve stimulation in rats.

PubMed

Ogawa, Fumio; Hanamitsu, Masakazu; Ayajiki, Kazuhide; Aimi, Yoshinari; Okamura, Tomio; Shimizu, Takeshi

2010-06-01

Neural control of nasal blood flow (NBF) has not been systematically investigated. The aim of the present study was to evaluate the effect of electrical stimulation of both sensory and parasympathetic nerves innervating the nasal mucosal arteries on NBF in rats. In anesthetized rats, nasociliary (sensory) nerves and postganglionic (parasympathetic) nerves derived from the right sphenopalatine ganglion were electrically stimulated. We measured NBF with a laser-Doppler flowmeter. The nerve stimulation increased NBF on both sides and increased the mean arterial blood pressure. The increase in NBF was larger on the ipsilateral side than on the contralateral side. Hexamethonium bromide, a ganglion blocker, abolished the stimulation-induced pressure effect and the increase in NBF on the contralateral side, but did not abolish the increase in NBF on the ipsilateral side. The remaining increase in NBF was abolished by N(G)-nitro-L-arginine, a nitric oxide synthase inhibitor. Histochemical analysis with nicotinamide adenine dinucleotide phosphate-diaphorase showed neuronal nitric oxide synthase-containing nerves that innervate nasal mucosal arteries. Nitric oxide released from parasympathetic nitrergic nerves may contribute to an increase in NBF in rats. The afferent impulses induced by sensory nerve stimulation may lead to an increase in mean arterial blood pressure that is partly responsible for the increase in NBF.

Caloric stimulation

MedlinePlus

... differences in temperature to diagnose damage to the acoustic nerve. This is the nerve that is involved ... This test stimulates your acoustic nerve by delivering cold or warm water or air into your ear canal. When cold water or air enters your ...

Cross-hemispheric dopamine projections have functional significance

PubMed Central

Fox, Megan E.; Mikhailova, Maria A.; Bass, Caroline E.; Takmakov, Pavel; Gainetdinov, Raul R.; Budygin, Evgeny A.; Wightman, R. Mark

2016-01-01

Dopamine signaling occurs on a subsecond timescale, and its dysregulation is implicated in pathologies ranging from drug addiction to Parkinson’s disease. Anatomic evidence suggests that some dopamine neurons have cross-hemispheric projections, but the significance of these projections is unknown. Here we report unprecedented interhemispheric communication in the midbrain dopamine system of awake and anesthetized rats. In the anesthetized rats, optogenetic and electrical stimulation of dopamine cells elicited physiologically relevant dopamine release in the contralateral striatum. Contralateral release differed between the dorsal and ventral striatum owing to differential regulation by D2-like receptors. In the freely moving animals, simultaneous bilateral measurements revealed that dopamine release synchronizes between hemispheres and intact, contralateral projections can release dopamine in the midbrain of 6-hydroxydopamine–lesioned rats. These experiments are the first, to our knowledge, to show cross-hemispheric synchronicity in dopamine signaling and support a functional role for contralateral projections. In addition, our data reveal that psychostimulants, such as amphetamine, promote the coupling of dopamine transients between hemispheres. PMID:27298371

Identifying Otosclerosis with Aural Acoustical Tests of Absorbance, Group Delay, Acoustic Reflex Threshold, and Otoacoustic Emissions.

PubMed

Keefe, Douglas H; Archer, Kelly L; Schmid, Kendra K; Fitzpatrick, Denis F; Feeney, M Patrick; Hunter, Lisa L

2017-10-01

Otosclerosis is a progressive middle-ear disease that affects conductive transmission through the middle ear. Ear-canal acoustic tests may be useful in the diagnosis of conductive disorders. This study addressed the degree to which results from a battery of ear-canal tests, which include wideband reflectance, acoustic stapedius muscle reflex threshold (ASRT), and transient evoked otoacoustic emissions (TEOAEs), were effective in quantifying a risk of otosclerosis and in evaluating middle-ear function in ears after surgical intervention for otosclerosis. To evaluate the ability of the test battery to classify ears as normal or otosclerotic, measure the accuracy of reflectance in classifying ears as normal or otosclerotic, and evaluate the similarity of responses in normal ears compared with ears after surgical intervention for otosclerosis. A quasi-experimental cross-sectional study incorporating case control was used. Three groups were studied: one diagnosed with otosclerosis before corrective surgery, a group that received corrective surgery for otosclerosis, and a control group. The test groups included 23 ears (13 right and 10 left) with normal hearing from 16 participants (4 male and 12 female), 12 ears (7 right and 5 left) diagnosed with otosclerosis from 9 participants (3 male and 6 female), and 13 ears (4 right and 9 left) after surgical intervention from 10 participants (2 male and 8 female). Participants received audiometric evaluations and clinical immittance testing. Experimental tests performed included ASRT tests with wideband reference signal (0.25-8 kHz), reflectance tests (0.25-8 kHz), which were parameterized by absorbance and group delay at ambient pressure and at swept tympanometric pressures, and TEOAE tests using chirp stimuli (1-8 kHz). ASRTs were measured in ipsilateral and contralateral conditions using tonal and broadband noise activators. Experimental ASRT tests were based on the difference in wideband-absorbed sound power before and after presenting the activator. Diagnostic accuracy to classify ears as otosclerotic or normal was quantified by the area under the receiver operating characteristic curve (AUC) for univariate and multivariate reflectance tests. The multivariate predictor used a small number of input reflectance variables, each having a large AUC, in a principal components analysis to create independent variables and followed by a logistic regression procedure to classify the test ears. Relative to the results in normal ears, diagnosed otosclerosis ears more frequently showed absent TEOAEs and ASRTs, reduced ambient absorbance at 4 kHz, and a different pattern of tympanometric absorbance and group delay (absorbance increased at 2.8 kHz at the positive-pressure tail and decreased at 0.7-1 kHz at the peak pressure, whereas group delay decreased at positive and negative-pressure tails from 0.35-0.7 kHz, and at 2.8-4 kHz at positive-pressure tail). Using a multivariate predictor with three reflectance variables, tympanometric reflectance (AUC = 0.95) was more accurate than ambient reflectance (AUC = 0.88) in classifying ears as normal or otosclerotic. Reflectance provides a middle-ear test that is sensitive to classifying ears as otosclerotic or normal, which may be useful in clinical applications. American Academy of Audiology

Ipsilateral hemiparesis in ischemic stroke patients.

PubMed

Inatomi, Y; Nakajima, M; Yonehara, T; Ando, Y

2017-07-01

To investigate clinical characteristics of ipsilateral hemiparesis in ischemic stroke patients. Patients with acute ischemic stroke were prospectively examined. Ipsilateral hemiparesis was defined as hemiparesis ipsilateral to recent stroke lesions. Patients with ipsilateral hemiparesis were examined with functional neuroimaging studies including transcranial magnetic stimulation (TMS) and functional MRI. Of 8360 patients, ipsilateral hemiparesis was detected in 14 patients (0.17%, mean age 71±6 years, eight men). Lesions responsible for the recent strokes were located in the frontal cortex in three patients, corona radiata in seven, internal capsule in one, and pons in three. These lesions were located along the typical route of the corticospinal tract in all but one patient. Thirteen patients also had a past history of stroke contralateral to the recent lesions; 12 of these had motor deficits contralateral to past stroke lesions. During TMS, ipsilateral magnetic evoked potentials were evoked in two of seven patients and contralateral potentials were evoked in all seven. Functional MRI activated cerebral hemispheres ipsilaterally in eight of nine patients and contralaterally in all nine. Most patients with ipsilateral hemiparesis had a past history of stroke contralateral to the recent one, resulting in motor deficits contralateral to the earlier lesions. Moreover, functional neuroimaging findings indicated an active crossed corticospinal tract in all of the examined patients. Both findings suggest the contribution of the uncrossed corticospinal tract contralateral to stroke lesions as a post-stroke compensatory motor system. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Spinal NMDA-receptor dependent amplification of nociceptive transmission to rat primary somatosensory cortex (SI).

PubMed

Kalliomäki, Jarkko; Granmo, Marcus; Schouenborg, Jens

2003-07-01

The role of NMDA mechanisms in spinal pathways mediating acute nociceptive input to the somatosensory cortex is not clear. In this study, the effect of NMDA-antagonists on nociceptive C fibre transmission to the primary somatosensory cortex (SI) was investigated. Cortical field potentials evoked by CO(2)-laser stimulation of the skin were recorded in the halothane/nitrous oxide anaesthetized rat. The SI nociceptive evoked potential (EP) amplitudes were dependent on the frequency of noxious heat stimulation. The amplitudes of SI potentials evoked by CO(2)-laser pulses (duration 15-20 ms, stimulation energy 21-28 mJ/mm(2)) delivered at a frequency of 0.1 Hz were approximately 40% of the amplitudes of potentials evoked by 1.0 Hz stimulation. After intrathecal lumbar application of either of the NMDA-antagonists CPP or MK-801, the amplitudes of nociceptive SI potentials, evoked by 1.0 Hz stimulation of the contralateral hindpaw, were reduced to approximately 40% of controls. By contrast, field potentials evoked by 0.1 Hz stimulation of the hindpaw were unaffected by MK-801. SI potentials evoked by 1.0 Hz stimulation of the contralateral forepaw did not change after lumbar application of CPP or MK-801, indicating that the depression of hindpaw EPs was due to a segmental effect in the spinal cord. It is concluded that spinal NMDA-receptor mechanisms amplify the acute transmission of nociceptive C fiber input to SI in a frequency-dependent way.

Evolution of directional hearing in moths via conversion of bat detection devices to asymmetric pressure gradient receivers

PubMed Central

Reid, Andrew; Marin-Cudraz, Thibaut

2016-01-01

Small animals typically localize sound sources by means of complex internal connections and baffles that effectively increase time or intensity differences between the two ears. However, some miniature acoustic species achieve directional hearing without such devices, indicating that other mechanisms have evolved. Using 3D laser vibrometry to measure tympanum deflection, we show that female lesser waxmoths (Achroia grisella) can orient toward the 100-kHz male song, because each ear functions independently as an asymmetric pressure gradient receiver that responds sharply to high-frequency sound arriving from an azimuth angle 30° contralateral to the animal's midline. We found that females presented with a song stimulus while running on a locomotion compensation sphere follow a trajectory 20°–40° to the left or right of the stimulus heading but not directly toward it, movement consistent with the tympanum deflections and suggestive of a monaural mechanism of auditory tracking. Moreover, females losing their track typically regain it by auditory scanning—sudden, wide deviations in their heading—and females initially facing away from the stimulus quickly change their general heading toward it, orientation indicating superior ability to resolve the front–rear ambiguity in source location. X-ray computer-aided tomography (CT) scans of the moths did not reveal any internal coupling between the two ears, confirming that an acoustic insect can localize a sound source based solely on the distinct features of each ear. PMID:27849607

Results of an early hearing detection program.

PubMed

Borkoski Barreiro, Silvia A; Falcón González, Juan C; Bueno Yanes, Jorge; Pérez Bermúdez, José L; López Cano, Zoraida; Ramos Macías, Ángel

2013-01-01

Neonatal hearing loss is a public health problem that meets the requirements for submission to universal screening. Our objective was to analyse the results of the early hearing detection and intervention program implemented at our centre between January 2007 and December 2010. We studied 26,717 newborns during the period mentioned, using transient otoacoustic emissions (TOAEs) for the screening. The diagnostic phase was carried out at the hearing loss department. In our area, there were 27,935 births between January 2007 and December 2010. The screening was performed on 26,717 children. Of these, 24,173 had positive TOAEs, 1,040 had no TOAEs and 1,504 presented TOAEs in 1 ear with absence of TOAEs in the contralateral ear. Risk factors associated with hearing loss were found in 4,674 infants. In a second phase of the program, TOAEs were given to 5,156 children, of whom 4,626 had positive otoacoustic emissions in both ears, 323 had no TOAEs in 1 ear and 207 failed this second phase. Of all children studied, 3.8% were referred to auditory brainstem response (ABR) testing and 26 children entered the cochlear implant program. The program reached coverage of 95.64%. The early hearing detection and intervention program at our hospital is suitable for our environment, reaching 95.64% of coverage. We consider the relationship between effectiveness and efficiency to be positive. Copyright © 2012 Elsevier España, S.L. All rights reserved.

How minute sooglossid frogs hear without a middle ear.

PubMed

Boistel, Renaud; Aubin, Thierry; Cloetens, Peter; Peyrin, Françoise; Scotti, Thierry; Herzog, Philippe; Gerlach, Justin; Pollet, Nicolas; Aubry, Jean-François

2013-09-17

Acoustic communication is widespread in animals. According to the sensory drive hypothesis [Endler JA (1993) Philos Trans R Soc Lond B Biol Sci 340(1292):215-225], communication signals and perceptual systems have coevolved. A clear illustration of this is the evolution of the tetrapod middle ear, adapted to life on land. Here we report the discovery of a bone conduction-mediated stimulation of the ear by wave propagation in Sechellophryne gardineri, one of the world's smallest terrestrial tetrapods, which lacks a middle ear yet produces acoustic signals. Based on X-ray synchrotron holotomography, we measured the biomechanical properties of the otic tissues and modeled the acoustic propagation. Our models show how bone conduction enhanced by the resonating role of the mouth allows these seemingly deaf frogs to communicate effectively without a middle ear.

Neurogenin 1 Null Mutant Ears Develop Fewer, Morphologically Normal Hair Cells in Smaller Sensory Epithelia Devoid of Innervation

PubMed Central

Ma, Qiufu; Anderson, David J.

2000-01-01

The proneuronal gene neurogenin 1 (ngn1) is essential for development of the inner-ear sensory neurons that are completely absent in ngn1 null mutants. Neither afferent, efferent, nor autonomic nerve fibers were detected in the ears of ngn1 null mutants. We suggest that efferent and autonomic fibers are lost secondarily to the absence of afferents. In this article we show that ngn1 null mutants develop smaller sensory epithelia with morphologically normal hair cells. In particular, the saccule is reduced dramatically and forms only a small recess with few hair cells along a duct connecting the utricle with the cochlea. Hair cells of newborn ngn1 null mutants show no structural abnormalities, suggesting that embryonic development of hair cells is independent of innervation. However, the less regular pattern of dispersal within sensory epithelia may be caused by some effects of afferents or to the stunted growth of the sensory epithelia. Tracing of facial and stato-acoustic nerves in control and ngn1 null mutants showed that only the distal, epibranchial, placode-derived sensory neurons of the geniculate ganglion exist in mutants. Tracing further showed that these geniculate ganglion neurons project exclusively to the solitary tract. In addition to the normal complement of facial branchial and visceral motoneurons, ngn1 null mutants have some trigeminal motoneurons and contralateral inner-ear efferents projecting, at least temporarily, through the facial nerve. These data suggest that some neurons in the brainstem (e.g., inner-ear efferents, trigeminal motoneurons) require afferents to grow along and redirect to ectopic cranial nerve roots in the absence of their corresponding sensory roots. PMID:11545141

Quality of Life and Hearing Eight Years After Sudden Sensorineural Hearing Loss.

PubMed

Härkönen, Kati; Kivekäs, Ilkka; Rautiainen, Markus; Kotti, Voitto; Vasama, Juha-Pekka

2017-04-01

To explore long-term hearing results, quality of life (QoL), quality of hearing (QoH), work-related stress, tinnitus, and balance problems after idiopathic sudden sensorineural hearing loss (ISSNHL). Cross-sectional study. We reviewed the audiograms of 680 patients with unilateral ISSNHL on average 8 years after the hearing impairment, and then divided the patients into two study groups based on whether their ISSNHL had recovered to normal (pure tone average [PTA] ≤ 30 dB) or not (PTA > 30 dB). The inclusion criteria were a hearing threshold decrease of 30 dB or more in at least three contiguous frequencies occurring within 72 hours in the affected ear and normal hearing in the contralateral ear. Audiograms of 217 patients fulfilled the criteria. We reviewed their medical records; measured present QoL, QoH, and work-related stress with specific questionnaires; and updated the hearing status. Poor hearing outcome after ISSNHL was correlated with age, severity of hearing loss, and vertigo together with ISSNHL. Quality of life and QoH were statistically significantly better in patients with recovered hearing, and the patients had statistically significantly less tinnitus and balance problems. During the 8-year follow-up, the PTA of the affected ear deteriorated on average 7 dB, and healthy ear deteriorated 6 dB. Idiopathic sudden sensorineural hearing loss that failed to recover had a negative impact on long-term QoL and QoH. The hearing deteriorated as a function of age similarly both in the affected and the healthy ear, and there were no differences between the groups. The cumulative recurrence rate for ISSNHL was 3.5%. 4 Laryngoscope, 127:927-931, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Functional Ear (A)Symmetry in Brainstem Neural Activity Relevant to Encoding of Voice Pitch: A Precursor for Hemispheric Specialization?

ERIC Educational Resources Information Center

Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Bidelman, Gavin M.; Smalt, Christopher J.

2011-01-01

Pitch processing is lateralized to the right hemisphere; linguistic pitch is further mediated by left cortical areas. This experiment investigates whether ear asymmetries vary in brainstem representation of pitch depending on linguistic status. Brainstem frequency-following responses (FFRs) were elicited by monaural stimulation of the left and…

Real-time measurement of cerebral blood flow during and after repetitive transcranial magnetic stimulation: A near-infrared spectroscopy study.

PubMed

Park, Eunhee; Kang, Min Jae; Lee, Ahee; Chang, Won Hyuk; Shin, Yong-Il; Kim, Yun-Hee

2017-07-13

To confirm the interhemispheric modulation induced by low-frequency repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex, real-time regional cerebral blood flow (rCBF) was assessed using functional near-infrared spectroscopy (fNIRS) in the contralateral primary motor cortex (M1) and premotor cortex (PM). Ten right-handed healthy subjects completed two experimental sessions that were randomly arranged for real or sham rTMS session. In the real rTMS session, fNIRS data were acquired from the right M1 and PM area, while the motor hot spot of the left M1 was stimulated with 1Hz rTMS for 1200 pulses with two boosters. In the sham stimulation session, stimulation was delivered with a disconnected coil. During the real rTMS session, the concentration of oxyhemoglobin ([oxy-Hb]) in the right M1 increased continuously until the end of the stimulation. These changes lasted for 20min, while the right PM did not show a change in [oxy-Hb] concentration. On the other hand, the concentration of deoxy-hemoglobin ([deoxy-Hb]) decreased continuously in the right M1 and PM during the real rTMS stimulation, and this change lasted for 20min after the stimulation. The sham stimulation did not exhibit any significant change in both [oxy-Hb] and [deoxy-Hb] concentration during or after the stimulation. Application of 1Hz rTMS over M1 resulted in changes of rCBF in contralateral M1 and PM, which seemed to constitute a function of interhemispheric modulation of rTMS. The fNIRS data was able to detect this physiological change of neuromodulatory action of rTMS in real-time. Copyright © 2017. Published by Elsevier B.V.

[Gender differences in hemispheric interaction during distributed and directed attention].

PubMed

Razumnikova, O M; Vol'f, N V

2006-01-01

Gender differences in the functional hemispheric organization during memorization of dichotically presented verbal information in the situation of focused or non-focused attention were studied. Analysis of EEG coherence reactivity in six frequency bands (4-30 Hz) showed that the focused attention to stimuli presented to one ear as compared to divided attention between both ears was accompanied by an increase in the interhemispheric interaction in the thetal frequency band between the frontal cortical areas in men and between the parietoccipital areas in women. In the betal band, the focused attention was associated with a contralateral increase in the intrahemispheric coherence in men, whereas no significant difference in the intrahemispheric coherence was found in women. On the basis of coherence changes in the thetal and betal bands depending on the attention conditions together with the obtained correlation between coherence reactivity and word-recall scores, it may be suggested that verbal memorization in men is associated, predominantly, with the regulation from the anterior system of attention and from the posterior system in women.

Alteration of frequency range for binaural beats in acute low-tone hearing loss.

PubMed

Karino, Shotaro; Yamasoba, Tatsuya; Ito, Ken; Kaga, Kimitaka

2005-01-01

The effect of acute low-tone sensorineural hearing loss (ALHL) on the interaural frequency difference (IFD) required for perception of binaural beats (BBs) was investigated in 12 patients with unilateral ALHL and 7 patients in whom ALHL had lessened. A continuous pure tone of 30 dB sensation level at 250 Hz was presented to the contralateral, normal-hearing ear. The presence of BBs was determined by a subjective yes-no procedure as the frequency of a loudness-balanced test tone was gradually adjusted around 250 Hz in the affected ear. The frequency range in which no BBs were perceived (FRNB) was significantly wider in the patients with ALHL than in the controls, and FRNBs became narrower in the recovered ALHL group. Specifically, detection of slow BBs with a small IFD was impaired in this limited (10 s) observation period. The significant correlation between the hearing level at 250 Hz and FRNBs suggests that FRNBs represent the degree of cochlear damage caused by ALHL.

Reducing contralateral SI activity reveals hindlimb receptive fields in the SI forelimb-stump representation of neonatally amputated rats.

PubMed

Pluto, Charles P; Chiaia, Nicolas L; Rhoades, Robert W; Lane, Richard D

2005-09-01

In adult rats that sustained forelimb amputation on the day of birth, >30% of multiunit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) also respond to cutaneous hindlimb stimulation when cortical GABA(A+B) receptors are blocked (GRB). This study examined whether hindlimb receptive fields could also be revealed in forelimb-stump sites by reducing one known source of excitatory input to SI GABAergic neurons, the contralateral SI cortex. Corpus callosum projection neurons connect homotopic SI regions, making excitatory contacts onto pyramidal cells and interneurons. Thus in addition to providing monosynaptic excitation in SI, callosal fibers can produce disynaptic inhibition through excitatory synapses with inhibitory interneurons. Based on the latter of these connections, we hypothesized that inactivating the contralateral (intact) SI forelimb region would "unmask" normally suppressed hindlimb responses by reducing the activity of SI GABAergic neurons. The SI forelimb-stump representation was first mapped under normal conditions and then during GRB to identify stump/hindlimb responsive sites. After GRB had dissipated, the contralateral (intact) SI forelimb region was mapped and reversibly inactivated with injections of 4% lidocaine, and selected forelimb-stump sites were retested. Contralateral SI inactivation revealed hindlimb responses in approximately 60% of sites that were stump/hindlimb responsive during GRB. These findings indicate that activity in the contralateral SI contributes to the suppression of reorganized hindlimb receptive fields in neonatally amputated rats.

Theta burst stimulation over the primary motor cortex does not induce cortical plasticity in Parkinson's disease.

PubMed

Eggers, Carsten; Fink, Gereon R; Nowak, Dennis A

2010-10-01

The purpose of this study was to investigate whether a period of continuous theta burst stimulation (cTBS) induces cortical plasticity and thus improves bradykinesia of the upper limb in Parkinson's disease. In eight patients with Parkinson's disease (two females; mean age: 68.5 ± 5 years; disease duration: 4 ± 3 years) electrophysiological (motor evoked potentials, contralateral and ipsilateral silent period) and behavioural (Purdue pegboard test, UPDRS motor subscore) parameters were evaluated before (baseline condition) and after a 40-s period of (1) real or (2) sham continuous theta burst stimulation over the primary motor cortex contralateral to the more affected body side off dopaminergic drugs. Compared to baseline, cTBS did change neither measures of cortical excitability nor behavioural measures. cTBS over the primary motor cortex does not impact on cortical excitability or motor function of the upper limb in Parkinson's disease. We interpret these data to reflect impaired cortical plasticity in Parkinson's disease. This study is an important contribution to the knowledge about impaired plasticity in Parkinson's disease.

Effects of training programs based on ipsilateral voluntary and stimulated contractions on muscle strength and monopedal postural control of the contralateral limb.

PubMed

Kadri, Mohamed Abdelhafid; Noé, Frederic; Nouar, Merbouha Boulahbel; Paillard, Thierry

2017-09-01

To compare the effects of unilateral strength training by stimulated and voluntary contractions on muscle strength and monopedal postural control of the contralateral limb. 36 non-active healthy male subjects were recruited and split randomly into three groups. Two groups of 12 subjects took part in a strength-training program (3 sessions a week over 8 weeks) comprising 43 contractions of the quadriceps femoris of the ipsilateral limb (at 20% of the MVC). One group carried out voluntary contractions exclusively (VOL group), while the other group benefited exclusively from electro-induced contractions (NMES group). The other 12 subjects formed the control (CON) group. Assessments of MVC and monopedal postural control in static and dynamic postural tasks were performed with the ipsilateral (ISPI) and contralateral (CONTRA) limbs before (PRE) and after (POST) completion of the training program. After the training program, the MVC of the IPSI and CONTRA limbs increased similarly for both experimental groups (VOL and NMES). There were no significant improvements of monopedal postural control for the IPSI or CONTRA limbs in either the VOL or NMES experimental group. No change was observed for the CON group over the protocol period. The purposed training program with NMES vs VOL contractions induced strength gains but did not permit any improvement of contralateral monopedal postural control in healthy young subjects. This has potential for therapeutic application and allows clinicians to focus their training programs on dynamic and poly-articular exercises to improve the postural control in young subjects.

Subcortical functional reorganization due to early blindness

PubMed Central

Jiang, Fang; Fine, Ione; Watkins, Kate E.; Bridge, Holly

2015-01-01

Lack of visual input early in life results in occipital cortical responses to auditory and tactile stimuli. However, it remains unclear whether cross-modal plasticity also occurs in subcortical pathways. With the use of functional magnetic resonance imaging, auditory responses were compared across individuals with congenital anophthalmia (absence of eyes), those with early onset (in the first few years of life) blindness, and normally sighted individuals. We find that the superior colliculus, a “visual” subcortical structure, is recruited by the auditory system in congenital and early onset blindness. Additionally, auditory subcortical responses to monaural stimuli were altered as a result of blindness. Specifically, responses in the auditory thalamus were equally strong to contralateral and ipsilateral stimulation in both groups of blind subjects, whereas sighted controls showed stronger responses to contralateral stimulation. These findings suggest that early blindness results in substantial reorganization of subcortical auditory responses. PMID:25673746

SEPs to finger joint input lack the N20-P20 response that is evoked by tactile inputs: contrast between cortical generators in areas 3b and 2 in humans.

PubMed

Desmedt, J E; Ozaki, I

1991-01-01

A method using a DC servo motor is described to produce brisk angular movements at finger interphalangeal joints in humans. Small passive flexions of 2 degrees elicited sizable somatosensory evoked potentials (SEPs) starting with a contralateral positive P34 parietal response thought to reflect activation of a radial equivalent dipole generator in area 2 which receives joint inputs. By contrast, electric stimulation of tactile (non-joint) inputs from the distal phalanx evoked the usual contralateral negative N20 reflecting a tangential equivalent dipole generator in area 3b. Finger joint inputs also evoked a precentral positivity equivalent to the P22 of motor area 4, and a large frontal negativity equivalent to N30. It is suggested that natural stimulation allows human SEP components to be differentiated in conjunction with distinct cortical somatotopic projections.

Subcortical functional reorganization due to early blindness.

PubMed

Coullon, Gaelle S L; Jiang, Fang; Fine, Ione; Watkins, Kate E; Bridge, Holly

2015-04-01

Lack of visual input early in life results in occipital cortical responses to auditory and tactile stimuli. However, it remains unclear whether cross-modal plasticity also occurs in subcortical pathways. With the use of functional magnetic resonance imaging, auditory responses were compared across individuals with congenital anophthalmia (absence of eyes), those with early onset (in the first few years of life) blindness, and normally sighted individuals. We find that the superior colliculus, a "visual" subcortical structure, is recruited by the auditory system in congenital and early onset blindness. Additionally, auditory subcortical responses to monaural stimuli were altered as a result of blindness. Specifically, responses in the auditory thalamus were equally strong to contralateral and ipsilateral stimulation in both groups of blind subjects, whereas sighted controls showed stronger responses to contralateral stimulation. These findings suggest that early blindness results in substantial reorganization of subcortical auditory responses. Copyright © 2015 the American Physiological Society.

Perception of Suprasegmental Speech Features via Bimodal Stimulation: Cochlear Implant on One Ear and Hearing Aid on the Other

ERIC Educational Resources Information Center

Most, Tova; Harel, Tamar; Shpak, Talma; Luntz, Michal

2011-01-01

Purpose: The purpose of the study was to evaluate the contribution of acoustic hearing to the perception of suprasegmental features by adults who use a cochlear implant (CI) and a hearing aid (HA) in opposite ears. Method: 23 adults participated in this study. Perception of suprasegmental features--intonation, syllable stress, and word…

Contralateral Bimodal Stimulation: A Way to Enhance Speech Performance in Arabic-Speaking Cochlear Implant Patients.

PubMed

Abdeltawwab, Mohamed M; Khater, Ahmed; El-Anwar, Mohammad W

2016-01-01

The combination of acoustic and electric stimulation as a way to enhance speech recognition performance in cochlear implant (CI) users has generated considerable interest in the recent years. The purpose of this study was to evaluate the bimodal advantage of the FS4 speech processing strategy in combination with hearing aids (HA) as a means to improve low-frequency resolution in CI patients. Nineteen postlingual CI adults were selected to participate in this study. All patients wore implants on one side and HA on the contralateral side with residual hearing. Monosyllabic word recognition, speech in noise, and emotion and talker identification were assessed using CI with fine structure processing/FS4 and high-definition continuous interleaved sampling strategies, HA alone, and a combination of CI and HA. The bimodal stimulation showed improvement in speech performance and emotion identification for the question/statement/order tasks, which was statistically significant compared to patients with CI alone, but there were no significant statistical differences in intragender talker discrimination and emotion identification for the happy/angry/neutral tasks. The poorest performance was obtained with HA only, and it was statistically significant compared to the other modalities. The bimodal stimulation showed enhanced speech performance in CI patients, and it improves the limitations provided by electric or acoustic stimulation alone. © 2016 S. Karger AG, Basel.

A common neural element receiving rhythmic arm and leg activity as assessed by reflex modulation in arm muscles

PubMed Central

Tazoe, Toshiki; Nakajima, Tsuyoshi; Futatsubashi, Genki; Ohtsuka, Hiroyuki; Suzuki, Shinya; Zehr, E. Paul; Komiyama, Tomoyoshi

2016-01-01

Neural interactions between regulatory systems for rhythmic arm and leg movements are an intriguing issue in locomotor neuroscience. Amplitudes of early latency cutaneous reflexes (ELCRs) in stationary arm muscles are modulated during rhythmic leg or arm cycling but not during limb positioning or voluntary contraction. This suggests that interneurons mediating ELCRs to arm muscles integrate outputs from neural systems controlling rhythmic limb movements. Alternatively, outputs could be integrated at the motoneuron and/or supraspinal levels. We examined whether a separate effect on the ELCR pathways and cortico-motoneuronal excitability during arm and leg cycling is integrated by neural elements common to the lumbo-sacral and cervical spinal cord. The subjects performed bilateral leg cycling (LEG), contralateral arm cycling (ARM), and simultaneous contralateral arm and bilateral leg cycling (A&L), while ELCRs in the wrist flexor and shoulder flexor muscles were evoked by superficial radial (SR) nerve stimulation. ELCR amplitudes were facilitated by cycling tasks and were larger during A&L than during ARM and LEG. A low stimulus intensity during ARM or LEG generated a larger ELCR during A&L than the sum of ELCRs during ARM and LEG. We confirmed this nonlinear increase in single motor unit firing probability following SR nerve stimulation during A&L. Furthermore, motor-evoked potentials following transcranial magnetic and electrical stimulation did not show nonlinear potentiation during A&L. These findings suggest the existence of a common neural element of the ELCR reflex pathway that is active only during rhythmic arm and leg movement and receives convergent input from contralateral arms and legs. PMID:26961103

On the pharmacology of ascending, descending and recurrent postsynatic inhibition of the cuneothalamic relay cells in the cat

PubMed Central

Kelly, J. S.; Renaud, L. P.

1973-01-01

1. In cats decerebrated or anaesthetized with pentobarbitone, cells of the middle third of the cuneate nucleus that were excited by tactile stimulation of the ipsilateral forelimb (responding to displacement of hairs, skin or joints) and inhibited by electrical stimulation of the contralateral pyramid, were invariably inhibited by electrical stimulation of the ipsilateral forepaw and the contralateral forelimb nerves. 2. In 50% of the cats, the cells were more fully identified by placing electrodes stereotaxically in the contralateral medial lemniscus. Recurrent inhibition was always a concomitant of the antidromic action potential. 3. The intensity and the duration of inhibition evoked by all of these pathways was totally resistant to iontophoretic and intravenous strychnine in doses at least 5 times that required to block completely the response of the same cells to iontophoretic glycine and was extremely sensitive to either iontophoretic bicuculline or picrotoxin. 4. Although the inhibition was invariably sensitive to intravenous picrotoxin, no significant change occurred in the duration or intensity of the inhibition when bicuculline was administered intravenously (5 or 6 times) as repeated doses of 0·2 mg/kg. 5. Postsynaptic inhibition in the cuneate may be mediated by γ-aminobutyric acid released from the nerve terminals of a common pool of interneurones shared by ascending, descending and recurrent pathways. Since the receptors involved in this pathway are resistant to intravenous bicuculline, they may well be distinct from those responsible for changes in the primary afferent terminal excitability, usually believed to be associated with presynaptic inhibition. PMID:4357959

Congenital atresia of the external ear and tinnitus: a new syndrome.

PubMed

Shulman, Abraham; Strashun, Arnold M; Goldstein, Barbara; Lenhardt, Martin L

2006-01-01

Congenital atresia of the external ears and severe tinnitus has been reported by two patients to be contralateral to the atretic ear. The use of the nuclear medicine imaging technique of single-photon emission computed tomography (SPECT) of brain has demonstrated hypoperfusion in brain areas supplied by the middle cerebral artery on the side of the atretic ear. Ultrahigh-frequency audiometry (UHFA) has revealed a bilateral loss of hearing greater than expected for the age of affected patients. Quantitative electroencephalography (QEEG) has shown a significant central nervous system electrical dysfunction correlated with the SPECT of brain findings. One case is reported in detail at this time. Completion of the medical audiological tinnitus patient protocol, including SPECT of brain, UHFA, and QEEG, accurately established the clinical tinnitus diagnosis of predominantly a central-type tinnitus, a clinical hypothesis that the medical significance of the tinnitus is a "soft" sign of cerebrovascular disease, and provided a rationale for treatment directed to a presumed ischemia of brain based on a receptor-targeted therapy targeted to the GABA-A receptor, resulting in significant tinnitus relief. Questions that have arisen include (1) the incidence of occurrence of hypoperfusion of the middle cerebral artery in congenital atresia patients; (2) implications and long-term consequences of this finding in this patient population for development of cerebrovascular disease; (3) brain plasticity for tinnitus relief (i.e., neuronal reprogramming, particularly in response to treatment recommendations for complaints of the cochleovestibular system in general and specifically for tinnitus); (4) the clinical significance of the UHFA thresholds of bilateral hearing loss greater than expected for the age of the patient; and (5) whether congenital atresia of the external ear may be part of a syndrome that includes hypoperfusion in brain areas supplied by the middle cerebral artery on the side of the atretic ear, ultra-high-frequency bilateral loss of hearing greater than expected for the age of the patient, and significant central nervous system electrical dysfunction. As far as we can determine, these findings, highlighted by the brain SPECT, have not previously been reported in patients with congenital atresia of the external ear.

Functional correlates of the therapeutic and adverse effects evoked by thalamic stimulation for essential tremor

PubMed Central

Gibson, William S.; Jo, Hang Joon; Testini, Paola; Cho, Shinho; Felmlee, Joel P.; Welker, Kirk M.; Klassen, Bryan T.; Min, Hoon-Ki

2016-01-01

Deep brain stimulation is an established neurosurgical therapy for movement disorders including essential tremor and Parkinson’s disease. While typically highly effective, deep brain stimulation can sometimes yield suboptimal therapeutic benefit and can cause adverse effects. In this study, we tested the hypothesis that intraoperative functional magnetic resonance imaging could be used to detect deep brain stimulation-evoked changes in functional and effective connectivity that would correlate with the therapeutic and adverse effects of stimulation. Ten patients receiving deep brain stimulation of the ventralis intermedius thalamic nucleus for essential tremor underwent functional magnetic resonance imaging during stimulation applied at a series of stimulation localizations, followed by evaluation of deep brain stimulation-evoked therapeutic and adverse effects. Correlations between the therapeutic effectiveness of deep brain stimulation (3 months postoperatively) and deep brain stimulation-evoked changes in functional and effective connectivity were assessed using region of interest-based correlation analysis and dynamic causal modelling, respectively. Further, we investigated whether brain regions might exist in which activation resulting from deep brain stimulation might correlate with the presence of paraesthesias, the most common deep brain stimulation-evoked adverse effect. Thalamic deep brain stimulation resulted in activation within established nodes of the tremor circuit: sensorimotor cortex, thalamus, contralateral cerebellar cortex and deep cerebellar nuclei (FDR q < 0.05). Stimulation-evoked activation in all these regions of interest, as well as activation within the supplementary motor area, brainstem, and inferior frontal gyrus, exhibited significant correlations with the long-term therapeutic effectiveness of deep brain stimulation (P < 0.05), with the strongest correlation (P < 0.001) observed within the contralateral cerebellum. Dynamic causal modelling revealed a correlation between therapeutic effectiveness and attenuated within-region inhibitory connectivity in cerebellum. Finally, specific subregions of sensorimotor cortex were identified in which deep brain stimulation-evoked activation correlated with the presence of unwanted paraesthesias. These results suggest that thalamic deep brain stimulation in tremor likely exerts its effects through modulation of both olivocerebellar and thalamocortical circuits. In addition, our findings indicate that deep brain stimulation-evoked functional activation maps obtained intraoperatively may contain predictive information pertaining to the therapeutic and adverse effects induced by deep brain stimulation. PMID:27329768

Cooperative hand movements in post-stroke subjects: Neural reorganization.

PubMed

Schrafl-Altermatt, Miriam; Dietz, Volker

2016-01-01

Recent research indicates a task-specific neural coupling controlling cooperative hand movements reflected in bilateral electromyographic reflex responses in arm muscles following unilateral nerve stimulation. Reorganization of this mechanism was explored in post-stroke patients in this study. Electromyographic reflex responses in forearm muscles to unilateral electrical ulnar nerve stimulation were examined during cooperative and non-cooperative hand movements. Stimulation of the unaffected arm during cooperative hand movements led to electromyographic responses in bilateral forearm muscles, similar to those seen in healthy subjects, while stimulation of the affected side was followed only by ipsilateral responses. No contralateral reflex responses could be evoked in severely affected patients. The presence of contralateral responses correlated with the clinical motor impairment as assessed by the Fugl-Meyer test. The observations suggest that after stroke an impaired processing of afferent input from the affected side leads to a defective neural coupling and is associated with a greater involvement of fiber tracts from the unaffected hemisphere during cooperative hand movements. The mechanism of neural coupling underlying cooperative hand movements is shown to be defective in post-stroke patients. The neural re-organizations observed have consequences for the rehabilitation of hand function. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Organization of pontine reticulospinal inputs to motoneurons controlling axial and limb muscles in the neonatal mouse

PubMed Central

Sivertsen, Magne S.; Glover, Joel C.

2014-01-01

Using optical recording of synaptically mediated calcium transients and selective spinal lesions, we investigated the pattern of activation of spinal motoneurons (MNs) by the pontine reticulospinal projection in isolated brain stem-spinal cord preparations from the neonatal mouse. Stimulation sites throughout the region where the pontine reticulospinal neurons reside reliably activated MNs at cervical, thoracic, and lumbar levels. Activation was similar in MNs ipsi- and contralateral to the stimulation site, similar in medial and lateral motor columns that contain trunk and limb MNs, respectively, and similar in the L2 and L5 segments that predominantly contain flexor and extensor MNs, respectively. In nonlesioned preparations, responses in both ipsi- and contralateral MNs followed individual stimuli in stimulus trains nearly one-to-one (with few failures). After unilateral hemisection at C1 on the same side as the stimulation, responses had substantially smaller magnitudes and longer latencies and no longer followed individual stimuli. After unilateral hemisection at C1 on the side opposite to the stimulation, the responses were also smaller, but their latencies were not affected. Thus we distinguish two pontine reticulospinal pathways to spinal MNs, one uncrossed and the other crossed, of which the uncrossed pathway transmits more faithfully and appears to be more direct. PMID:24944221

21 CFR 874.1800 - Air or water caloric stimulator.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Air or water caloric stimulator. 874.1800 Section 874.1800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1800 Air or water caloric stimulator. (a) Identification. An air or wate...

Fundamental frequency information for speech recognition via bimodal stimulation: cochlear implant in one ear and hearing aid in the other.

PubMed

Shpak, Talma; Most, Tova; Luntz, Michal

2014-01-01

The aim of this study was to examine the role of fundamental frequency (F0) information in improving speech perception of individuals with a cochlear implant (CI) who use a contralateral hearing aid (HA). The authors hypothesized that in bilateral-bimodal (CI/HA) users the perception of natural prosody speech would be superior to the perception of speech with monotonic flattened F0 contour, whereas in unilateral CI users the perception of both speech signals would be similar. They also hypothesized that in the CI/HA listening condition the speech perception scores would improve as a function of the magnitude of the difference between the F0 characteristics of the target speech signal and the F0 characteristics of the competitors, whereas in the CI-alone condition such a pattern would not be recognized, or at least not as clearly. Two tests were administered to 29 experienced CI/HA adult users who, regardless of their residual hearing or speech perception abilities, had chosen to continue using an HA in the nonimplanted ear for at least 75% of their waking hours. In the first test, the difference between the perception of speech characterized by natural prosody and speech characterized by monotonic flattened F0 contour was assessed in the presence of babble noise produced by three competing male talkers. In the second test the perception of semantically unpredictable sentences was evaluated in the presence of a competing reversed speech sentence spoken by different single talkers with different F0 characteristics. Each test was carried out under two listening conditions: CI alone and CI/HA. Under both listening conditions, the perception of speech characterized by natural prosody was significantly better than the perception of speech in which monotonic F0 contour was flattened. Differences between the scores for natural prosody and for monotonic flattened F0 speech contour were significantly greater, however, in the CI/HA condition than with CI alone. In the second test, the overall scores for perception of semantically unpredictable sentences in the presence of all competitors were higher in the CI/HA condition in the presence of all competitors. In both listening conditions, scores increased significantly with increasing difference between the F0 characteristics of the target speech signal and the F0 characteristics of the competitor. The higher scores obtained in the CI/HA condition than with CI alone in both of the task-specific tests suggested that the use of a contralateral HA provides improved low-frequency information, resulting in better performance by the CI/HA users.

Interactions between Dorsal and Ventral Root Stimulation on the Generation of Locomotor-Like Activity in the Neonatal Mouse Spinal Cord

PubMed Central

2016-01-01

Abstract We investigated whether dorsal (DR) and ventral root (VR) stimulus trains engage common postsynaptic components to activate the central pattern generator (CPG) for locomotion in the neonatal mouse spinal cord. VR stimulation did not activate the first order interneurons mediating the activation of the locomotor CPG by sacrocaudal afferent stimulation. Simultaneous stimulation of adjacent dorsal or ventral root pairs, subthreshold for evoking locomotor-like activity, did not summate to activate the CPG. This suggests that locomotor-like activity is triggered when a critical class of efferent or afferent axons is stimulated and does not depend on the number of stimulated axons or activated postsynaptic neurons. DR- and VR-evoked episodes exhibited differences in the coupling between VR pairs. In DR-evoked episodes, the coupling between the ipsilateral and contralateral flexor/extensor roots was similar and stronger than the bilateral extensor roots. In VR-evoked episodes, ipsilateral flexor/extensor coupling was stronger than both the contralateral flexor/extensor and the bilateral extensor coupling. For both types of stimulation, the coupling was greatest between the bilateral L1/L2 flexor-dominated roots. This indicates that the recruitment and/or the firing pattern of motoneurons differed in DR and VR-evoked episodes. However, the DR and VR trains do not appear to activate distinct CPGs because trains of DR and VR stimuli at frequencies too low to evoke locomotor-like activity did so when they were interleaved. These results indicate that the excitatory actions of VR stimulation converge onto the CPG through an unknown pathway that is not captured by current models of the locomotor CPG. PMID:27419215

Localization and interaural time difference (ITD) thresholds for cochlear implant recipients with preserved acoustic hearing in the implanted ear

PubMed Central

Gifford, René H.; Grantham, D. Wesley; Sheffield, Sterling W.; Davis, Timothy J.; Dwyer, Robert; Dorman, Michael F.

2014-01-01

The purpose of this study was to investigate horizontal plane localization and interaural time difference (ITD) thresholds for 14 adult cochlear implant recipients with hearing preservation in the implanted ear. Localization to broadband noise was assessed in an anechoic chamber with a 33-loudspeaker array extending from −90 to +90°. Three listening conditions were tested including bilateral hearing aids, bimodal (implant + contralateral hearing aid) and best aided (implant + bilateral hearing aids). ITD thresholds were assessed, under headphones, for low-frequency stimuli including a 250-Hz tone and bandpass noise (100–900 Hz). Localization, in overall rms error, was significantly poorer in the bimodal condition (mean: 60.2°) as compared to both bilateral hearing aids (mean: 46.1°) and the best-aided condition (mean: 43.4°). ITD thresholds were assessed for the same 14 adult implant recipients as well as 5 normal-hearing adults. ITD thresholds were highly variable across the implant recipients ranging from the range of normal to ITDs not present in real-world listening environments (range: 43 to over 1600 μs). ITD thresholds were significantly correlated with localization, the degree of interaural asymmetry in low-frequency hearing, and the degree of hearing preservation related benefit in the speech reception threshold (SRT). These data suggest that implant recipients with hearing preservation in the implanted ear have access to binaural cues and that the sensitivity to ITDs is significantly correlated with localization and degree of preserved hearing in the implanted ear. PMID:24607490

Localization and interaural time difference (ITD) thresholds for cochlear implant recipients with preserved acoustic hearing in the implanted ear.

PubMed

Gifford, René H; Grantham, D Wesley; Sheffield, Sterling W; Davis, Timothy J; Dwyer, Robert; Dorman, Michael F

2014-06-01

The purpose of this study was to investigate horizontal plane localization and interaural time difference (ITD) thresholds for 14 adult cochlear implant recipients with hearing preservation in the implanted ear. Localization to broadband noise was assessed in an anechoic chamber with a 33-loudspeaker array extending from -90 to +90°. Three listening conditions were tested including bilateral hearing aids, bimodal (implant + contralateral hearing aid) and best aided (implant + bilateral hearing aids). ITD thresholds were assessed, under headphones, for low-frequency stimuli including a 250-Hz tone and bandpass noise (100-900 Hz). Localization, in overall rms error, was significantly poorer in the bimodal condition (mean: 60.2°) as compared to both bilateral hearing aids (mean: 46.1°) and the best-aided condition (mean: 43.4°). ITD thresholds were assessed for the same 14 adult implant recipients as well as 5 normal-hearing adults. ITD thresholds were highly variable across the implant recipients ranging from the range of normal to ITDs not present in real-world listening environments (range: 43 to over 1600 μs). ITD thresholds were significantly correlated with localization, the degree of interaural asymmetry in low-frequency hearing, and the degree of hearing preservation related benefit in the speech reception threshold (SRT). These data suggest that implant recipients with hearing preservation in the implanted ear have access to binaural cues and that the sensitivity to ITDs is significantly correlated with localization and degree of preserved hearing in the implanted ear. Copyright © 2014. Published by Elsevier B.V.

Sirviendo a los estudiantes sordos que tienen Los implantes cocleares. Hoja de consejos de PEPNet (Serving Deaf Students Who Have Cochlear Implants. PEPNet Tipsheet)

ERIC Educational Resources Information Center

Clark, Catherine

2010-01-01

This version of "Serving Deaf Students Who Have Cochlear Implants. PEPNet Tipsheet," written in Spanish, describes how cochlear implants (CIs) work. CIs are complex electronic devices surgically implanted under the skin behind the ear. These devices utilize electrodes placed in the inner ear (the cochlea) to stimulate the auditory nerve of…

The Balance of Excitatory and Inhibitory Synaptic Inputs for Coding Sound Location

PubMed Central

Ono, Munenori

2014-01-01

The localization of high-frequency sounds in the horizontal plane uses an interaural-level difference (ILD) cue, yet little is known about the synaptic mechanisms that underlie processing this cue in the inferior colliculus (IC) of mouse. Here, we study the synaptic currents that process ILD in vivo and use stimuli in which ILD varies around a constant average binaural level (ABL) to approximate sounds on the horizontal plane. Monaural stimulation in either ear produced EPSCs and IPSCs in most neurons. The temporal properties of monaural responses were well matched, suggesting connected functional zones with matched inputs. The EPSCs had three patterns in response to ABL stimuli, preference for the sound field with the highest level stimulus: (1) contralateral; (2) bilateral highly lateralized; or (3) at the center near 0 ILD. EPSCs and IPSCs were well correlated except in center-preferred neurons. Summation of the monaural EPSCs predicted the binaural excitatory response but less well than the summation of monaural IPSCs. Binaural EPSCs often showed a nonlinearity that strengthened the response to specific ILDs. Extracellular spike and intracellular current recordings from the same neuron showed that the ILD tuning of the spikes was sharper than that of the EPSCs. Thus, in the IC, balanced excitatory and inhibitory inputs may be a general feature of synaptic coding for many types of sound processing. PMID:24599475

The Codacs™ direct acoustic cochlear implant actuator: exploring alternative stimulation sites and their stimulation efficiency.

PubMed

Grossöhmichen, Martin; Salcher, Rolf; Kreipe, Hans-Heinrich; Lenarz, Thomas; Maier, Hannes

2015-01-01

This work assesses the efficiency of the Codacs system actuator (Cochlear Ltd., Sydney Australia) in different inner ear stimulation modalities. Originally the actuator was intended for direct perilymph stimulation after stapedotomy using a piston prosthesis. A possible alternative application is the stimulation of middle ear structures or the round window (RW). Here the perilymph stimulation with a K-piston through a stapes footplate (SFP) fenestration (N = 10) as well as stimulation of the stapes head (SH) with a Bell prosthesis (N = 9), SFP stimulation with an Omega/Aerial prosthesis (N = 8) and reverse RW stimulation (N = 10) were performed in cadaveric human temporal bones (TBs). Codacs actuator output is expressed as equivalent sound pressure level (eq. SPL) using RW and SFP displacement responses, measured by Laser Doppler velocimetry as reference. The axial actuator coupling force in stimulation of stapes and RW was adjusted to ~5 mN. The Bell prosthesis and Omega/Aerial prosthesis stimulation generated similar mean eq. SPLs (Bell: 127.5-141.8 eq. dB SPL; Omega/Aerial: 123.6-143.9 eq. dB SPL), being significantly more efficient than K-piston perilymph stimulation (108.6-131.6 eq. dB SPL) and RW stimulation (108.3-128.2 eq. dB SPL). Our results demonstrate that SH, SFP and RW are adequate alternative stimulation sites for the Codacs actuator using coupling prostheses and an axial coupling force of ~5 mN. Based on the eq. SPLs, all investigated methods were adequate for in vivo hearing aid applications, provided that experimental conditions including constant coupling force will be implemented.

Clinical Phenotype Predicts Early Staged Bilateral Deep Brain Stimulation in Parkinson’s Disease

PubMed Central

Sung, Victor W.; Watts, Ray L.; Schrandt, Christian J.; Guthrie, Stephanie; Wang, Deli; Amara, Amy W.; Guthrie, Barton L.; Walker, Harrison C.

2014-01-01

Object While many centers place bilateral DBS systems simultaneously, unilateral STN DBS followed by a staged contralateral procedure has emerged as a treatment option for many patients. However little is known about whether the preoperative phenotype predicts when staged placement of a DBS electrode in the opposite subthalamic nucleus will be required. We aimed to determine whether preoperative clinical phenotype predicts early staged placement of a second subthalamic deep brain stimulation (DBS) electrode in patients who undergo unilateral subthalamic DBS for Parkinson's disease (PD). Methods Eighty-two consecutive patients with advanced PD underwent unilateral subthalamic DBS contralateral to the most affected hemibody and had at least 2 years of follow-up. Multivariate logistic regression determined preoperative characteristics that predicted staged placement of a second electrode in the opposite subthalamic nucleus. Preoperative measurements included aspects of the Unified Parkinson Disease Rating Scale (UPDRS), motor asymmetry index, and body weight. Results At 2 years follow-up, 28 of the 82 patients (34%) had undergone staged placement of a contralateral electrode while the remainder chose to continue with unilateral stimulation. Statistically significant improvements in UPDRS total and part 3 scores were retained at the end of the 2 year follow-up period in both subsets of patients. Multivariate logistic regression showed that the most important predictors for early staged placement of a second subthalamic stimulator were low asymmetry index (odds ratio 13.4; 95% confidence interval 2.8, 64.9), high tremor subscore (OR 7.2; CI 1.5, 35.0), and low body weight (OR 5.5; CI 1.4, 22.3). Conclusions This single center study provides evidence that elements of the preoperative PD phenotype predict whether patients will require early staged bilateral subthalamic DBS. These data may aid in the management of patients with advanced PD who undergo subthalamic DBS. PMID:24074493

The Corticofugal Effects of Auditory Cortex Microstimulation on Auditory Nerve and Superior Olivary Complex Responses Are Mediated via Alpha-9 Nicotinic Receptor Subunit

PubMed Central

Aedo, Cristian; Terreros, Gonzalo; León, Alex; Delano, Paul H.

2016-01-01

Background and Objective The auditory efferent system is a complex network of descending pathways, which mainly originate in the primary auditory cortex and are directed to several auditory subcortical nuclei. These descending pathways are connected to olivocochlear neurons, which in turn make synapses with auditory nerve neurons and outer hair cells (OHC) of the cochlea. The olivocochlear function can be studied using contralateral acoustic stimulation, which suppresses auditory nerve and cochlear responses. In the present work, we tested the proposal that the corticofugal effects that modulate the strength of the olivocochlear reflex on auditory nerve responses are produced through cholinergic synapses between medial olivocochlear (MOC) neurons and OHCs via alpha-9/10 nicotinic receptors. Methods We used wild type (WT) and alpha-9 nicotinic receptor knock-out (KO) mice, which lack cholinergic transmission between MOC neurons and OHC, to record auditory cortex evoked potentials and to evaluate the consequences of auditory cortex electrical microstimulation in the effects produced by contralateral acoustic stimulation on auditory brainstem responses (ABR). Results Auditory cortex evoked potentials at 15 kHz were similar in WT and KO mice. We found that auditory cortex microstimulation produces an enhancement of contralateral noise suppression of ABR waves I and III in WT mice but not in KO mice. On the other hand, corticofugal modulations of wave V amplitudes were significant in both genotypes. Conclusion These findings show that the corticofugal modulation of contralateral acoustic suppressions of auditory nerve (ABR wave I) and superior olivary complex (ABR wave III) responses are mediated through MOC synapses. PMID:27195498

Middle-Ear Pressure Gain and Cochlear Partition Differential Pressure in Chinchilla

PubMed Central

Ravicz, Michael E.; Slama, Michaël C.C.; Rosowski, John J.

2009-01-01

An important step to describe the effects of inner-ear impedance and pathologies on middle- and inner-ear mechanics is to quantify middle- and inner-ear function in the normal ear. We present middle-ear pressure gain GMEP and trans-cochlear-partition differential sound pressure ΔPCP in chinchilla from 100 Hz to 30 kHz derived from measurements of intracochlear sound pressures in scala vestibuli PSV and scala tympani PST and ear-canal sound pressure near the tympanic membrane PTM. These measurements span the chinchilla's auditory range. GMEP had constant magnitude of about 20 dB between 300 Hz and 20 kHz and phase that implies a 40-μs delay, values with some similarities to previous measurements in chinchilla and other species. ΔPCP was similar to GMEP below about 10 kHz and lower in magnitude at higher frequencies, decreasing to 0 dB at 20 kHz. The high-frequency rolloff correlates with the audiogram and supports the idea that middle-ear transmission limits high-frequency hearing, providing a stronger link between inner-ear macromechanics and hearing. We estimate the cochlear partition impedance ZCP from these and previous data. The chinchilla may be a useful animal model for exploring the effects of nonacoustic inner-ear stimulation such as “bone conduction” on cochlear mechanics. PMID:19945521

Should children who use cochlear implants wear hearing aids in the opposite ear?

PubMed

Ching, T Y; Psarros, C; Hill, M; Dillon, H; Incerti, P

2001-10-01

The aim of this study was to investigate 1) whether a hearing aid needs to be adjusted differently depending on whether a child wears a cochlear implant or another hearing aid in the contralateral ear; 2) whether the use of a hearing aid and a cochlear implant in opposite ears leads to binaural interference; and 3) whether the use of a hearing aid and a cochlear implant in opposite ears leads to binaural benefits in speech perception, localization, and communicative functioning in real life. Sixteen children participated in this study. All children used a Nucleus 22 or Nucleus 24 cochlear implant system programmed with the SPEAK strategy in one ear. The hearing aid amplification requirements in the nonimplanted ear of these children were determined using two procedures. A paired comparison technique was used to identify the frequency response that was best for speech intelligibility in quiet, and a loudness balancing technique was used to match the loudness of speech in the ear with a hearing aid to that with a cochlear implant. Eleven of the 16 children participated in the investigation of binaural effects. Performance in speech perception, localization, and communicative functioning was assessed under four aided conditions: cochlear implant with hearing aid as worn, cochlear implant alone, hearing aid alone, and cochlear implant with hearing aid adjusted according to individual requirements. Fifteen of the 16 children whose amplification requirements were determined preferred a hearing aid frequency response that was within +/-6 dB/octave of the NAL-RP prescription. On average, the children required 6 dB more gain than prescribed to balance the loudness of the implanted ear for a speech signal presented at 65 dB SPL. For all 11 children whose performance was evaluated for investigating binaural effects, there was no indication of significantly poorer performance under bilaterally aided conditions compared with unilaterally aided conditions. On average, there were significant benefits in speech perception, localization, and aural/oral function when the children used cochlear implants with adjusted hearing aids than when they used cochlear implants alone. All individuals showed benefits in at least one of the measures. Hearing aids for children who also use cochlear implants can be selected using the NAL-RP prescription. Adjustment of hearing aid gain to match loudness in the implanted ear can facilitate integration of signals from both ears, leading to better speech perception. Given that there are binaural advantages from using cochlear implants with hearing aids in opposite ears, clinicians should advise parents and other professionals about these potential advantages, and facilitate bilateral amplification by adjusting hearing aids after stable cochlear implant MAPs are established.

Aronia melanocarpa Concentrate Ameliorates Pro-Inflammatory Responses in HaCaT Keratinocytes and 12-O-Tetradecanoylphorbol-13-Acetate-Induced Ear Edema in Mice.

PubMed

Goh, Ah Ra; Youn, Gi Soo; Yoo, Ki-Yeon; Won, Moo Ho; Han, Sang-Zin; Lim, Soon Sung; Lee, Keun Wook; Choi, Soo Young; Park, Jinseu

2016-07-01

Abnormal expression of pro-inflammatory mediators such as cell adhesion molecules and cytokines has been implicated in various inflammatory skin diseases, including atopic dermatitis. In this study, we investigated the anti-inflammatory activity of Aronia melanocarpa concentrate (AC) and its action mechanisms using in vivo and in vitro skin inflammation models. Topical application of AC on mouse ears significantly suppressed 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear edema formation, as judged by measuring ear thickness and weight, and histological analysis. Topical administration of AC also reduced the expression of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 in TPA-stimulated mouse ears. Pretreatment with AC suppressed TNF-α-induced ICAM-I expression and subsequent monocyte adhesiveness in human keratinocyte cell line HaCaT. In addition, AC significantly decreased intracellular reactive oxygen species (ROS) generation as well as mitogen-activated protein kinase (MAPK) activation in TNF-α-stimulated HaCaT cells. AC and its constituent cyanidin 3-glucoside also attenuated TNF-α-induced IKK activation, IκB degradation, p65 phosphorylation/nuclear translocation, and p65 DNA binding activity in HaCaT cells. Overall, our results indicate that AC exerts anti-inflammatory activities by inhibiting expression of pro-inflammatory mediators in vitro and in vivo possibly through suppression of ROS-MAPK-NF-κB signaling pathways. Therefore, AC may be developed as a therapeutic agent to treat various inflammatory skin diseases.

Contralaterally Controlled Neuromuscular Electrical Stimulation for Recovery of Ankle Dorsiflexion

PubMed Central

Knutson, Jayme S.; Hansen, Kristine; Nagy, Jennifer; Bailey, Stephanie N.; Gunzler, Douglas D.; Sheffler, Lynne R.; Chae, John

2013-01-01

Objective Compare the effects of contralaterally controlled neuromuscular electrical stimulation (CCNMES) versus cyclic neuromuscular electrical stimulation (NMES) on lower extremity impairment, functional ambulation, and gait characteristics. Design Twenty-six stroke survivors with chronic (≥6mo) footdrop during ambulation were randomly assigned to six weeks of CCNMES or cyclic NMES. Both groups had ten sessions per week of self-administered home application of either CCNMES or cyclic NMES plus two sessions per week of gait training with a physical therapist. Primary outcomes included lower extremity Fugl-Meyer score, modified Emory Functional Ambulation Profile, and gait velocity. Assessments were made at pretreatment, posttreatment, and at 1 and 3 months posttreatment. Results There were no significant differences between groups in the outcome trajectories for any of the measures. With data from both groups pooled, there were significant but modest and sustained improvements in the Fugl-Meyer score and the modified Emory Functional Ambulation Profile, but not in gait velocity. Conclusions The results support the hypothesis that gait training combined with either CCNMES or cyclic NMES reduces lower extremity impairment and functional ambulation, but do not support the hypothesis that CCNMES is more effective than cyclic NMES in chronic patients. PMID:23867888

Pyramidal tract stimulation restores normal corticospinal tract connections and visuomotor skill after early postnatal motor cortex activity blockade

PubMed Central

Salimi, I; Friel, KM; Martin, JH

2008-01-01

Motor development depends on forming specific connections between the corticospinal tract (CST) and the spinal cord. Blocking CST activity in kittens during the critical period for establishing connections with spinal motor circuits results in permanent impairments in connectivity and function. The changes in connections are consistent with the hypothesis that the inactive tract is less competitive in developing spinal connections than the active tract. In this study we tested the competition hypothesis by determining if activating CST axons, after prior silencing during the critical period, abrogated development of aberrant corticospinal connections and motor impairments. In kittens, we inactivated motor cortex by muscimol infusion between postnatal weeks 5-7. We next electrically stimulated CST axons in the medullary pyramid 2.5 hours daily, between weeks 7-10. In controls (n=3), CST terminations were densest within the contralateral deeper, premotor, spinal layers. After prior inactivation (n=3), CST terminations were densest within the dorsal, somatic sensory, layers. There were more ipsilateral terminations from the active tract. During visually guided locomotion, there was a movement endpoint impairment. Stimulation after inactivation (n=6) resulted in significantly fewer terminations in the sensory layers and more in the premotor layers, and fewer ipsilateral connections from active cortex. Chronic stimulation reduced the current threshold for evoking contralateral movements by pyramidal stimulation, suggesting strengthening of connections. Importantly, stimulation significantly improved stepping accuracy. These findings show the importance of activity-dependent processes in specifying CST connections. They also provide a strategy for harnessing activity to rescue CST axons at risk of developing aberrant connections after CNS injury. PMID:18632946

Molecular cloning of the Coch gene of guinea pig inner ear and its expression analysis in cultured fibrocytes of the spiral ligament.

PubMed

Li, Lishu; Ikezono, Tetsuo; Sekine, Kuwon; Shindo, Susumu; Matsumura, Tomohiro; Pawankar, Ruby; Ichimiya, Issei; Yagi, Toshiaki

2010-08-01

We have cloned guinea pig Coch cDNA and the sequence information will be useful for future molecular study combined with physiological experiments. Proper Coch gene expression appears to be dependent on the unique extracellular micro-environment of the inner ear in vivo. These results provide insight into the Coch gene expression and its regulation. To characterize the guinea pig Coch gene, we performed molecular cloning and expression analysis in the inner ear and cultured fibrocytes of the spiral ligament. The Coch cDNA was isolated using RACE. Cochlin isofoms were studied by Western blot using three different types of mammalian inner ear. The cochlear fibrocytes were cultured and characterized by immunostaining. Coch gene expression in the fibrocytes was investigated and the influence of cytokine stimulation was evaluated. The full-length 1991 bp Coch cDNA that encodes a 553 amino acid protein was isolated. The sequence had significant homology with other mammals, and the sizes of the Cochlin isoforms were identical. In the cultured fibrocytes, Coch mRNA was expressed in a very small amount and the isoform production was different, compared with the results in vivo. Cytokine stimulation did not alter the level of mRNA expression or isoform formation.

Localization of soluble guanylate cyclase activity in the guinea pig inner ear.

PubMed

Takumida, M; Anniko, M; Popa, R; Zhang, D M

2000-01-01

The aim of this study was to characterize the nitric oxide (NO) receptor soluble guanylate cyclase (sGC), to determine the cells targeted by NO and to elucidate the function of the NO/cGMP pathway in the inner ear. sGC activity in the inner ear was localized by immunohistochemical detection of NO-stimulated cGMP. Soluble guanylate cyclase activity in the cochlea was detected in the nerve endings underneath the outer and inner hair cells, supporting cells, stria vascularis and vessels. In the vestibular organs, sGC activity was detected in the cytoplasm of sensory cells, nerve fibres, dark cells and transitional cells and vessels. These findings suggest that the NO/cGMP pathway may be involved in regulatory processes in neurotransmission, blood flow and inner ear fluid homeostasis.

Cochlear Patency After Transmastoid Labyrinthectomy for Ménière's Syndrome.

PubMed

Sargent, Eric W; Liao, Eric; Gonda, Roger L

2016-08-01

Labyrinthectomy is considered the "gold standard" in the treatment of intractable vertigo attacks because of Ménière's Disease (MD) but sacrifices all residual hearing. Interest in auditory rehabilitation has lead to cochlear implantation in some patients. Concern remains that the cochlear lumen may fill with tissue or bone after surgery. This study sought to determine the incidence of obliteration of the cochlea after transmastoid labyrinthectomy. Retrospective observational study. Tertiary referral center. Eighteen patients with intractable vertigo from MD who underwent surgery. Transmastoid labyrinthectomy between 2008 and 2013. Cochleas were imaged with unenhanced, heavily T2-weighted magnetic resonance imaging (MRI). Presence of symmetrical cochlear fluid signals on MRI. There was no loss of fluid signal in the cochleas of operated ear compared with the contralateral, unoperated ear in any subject an average of 3 years (standard deviation [SD]: 1.2) after surgery. Five of 18 patients had the vestibule blocked with bone wax at the time of surgery. Blocking the vestibule with bone wax did not change the cochlear fluid signal. The risk of cochlear obstruction after labyrinthectomy for MD is very low. The significance of this finding is that patients with MD who undergo labyrinthectomy will likely remain candidates for cochlear implantation in the labyrinthectomized ear long after surgery if this becomes needed. Immediate cochlear implantation or placement of a cochlear lumen keeper during labyrinthectomy for MD is probably not necessary.

A common neural element receiving rhythmic arm and leg activity as assessed by reflex modulation in arm muscles.

PubMed

Sasada, Syusaku; Tazoe, Toshiki; Nakajima, Tsuyoshi; Futatsubashi, Genki; Ohtsuka, Hiroyuki; Suzuki, Shinya; Zehr, E Paul; Komiyama, Tomoyoshi

2016-04-01

Neural interactions between regulatory systems for rhythmic arm and leg movements are an intriguing issue in locomotor neuroscience. Amplitudes of early latency cutaneous reflexes (ELCRs) in stationary arm muscles are modulated during rhythmic leg or arm cycling but not during limb positioning or voluntary contraction. This suggests that interneurons mediating ELCRs to arm muscles integrate outputs from neural systems controlling rhythmic limb movements. Alternatively, outputs could be integrated at the motoneuron and/or supraspinal levels. We examined whether a separate effect on the ELCR pathways and cortico-motoneuronal excitability during arm and leg cycling is integrated by neural elements common to the lumbo-sacral and cervical spinal cord. The subjects performed bilateral leg cycling (LEG), contralateral arm cycling (ARM), and simultaneous contralateral arm and bilateral leg cycling (A&L), while ELCRs in the wrist flexor and shoulder flexor muscles were evoked by superficial radial (SR) nerve stimulation. ELCR amplitudes were facilitated by cycling tasks and were larger during A&L than during ARM and LEG. A low stimulus intensity during ARM or LEG generated a larger ELCR during A&L than the sum of ELCRs during ARM and LEG. We confirmed this nonlinear increase in single motor unit firing probability following SR nerve stimulation during A&L. Furthermore, motor-evoked potentials following transcranial magnetic and electrical stimulation did not show nonlinear potentiation during A&L. These findings suggest the existence of a common neural element of the ELCR reflex pathway that is active only during rhythmic arm and leg movement and receives convergent input from contralateral arms and legs. Copyright © 2016 the American Physiological Society.

Corticospinal control of the thumb-index grip depends on precision of force control: a transcranial magnetic stimulation and functional magnetic resonance imagery study in humans.

PubMed

Bonnard, M; Galléa, C; De Graaf, J B; Pailhous, J

2007-02-01

The corticospinal system (CS) is well known to be of major importance for controlling the thumb-index grip, in particular for force grading. However, for a given force level, the way in which the involvement of this system could vary with increasing demands on precise force control is not well-known. Using transcranial magnetic stimulation and functional magnetic resonance imagery, the present experiments investigated whether increasing the precision demands while keeping the averaged force level similar during an isometric dynamic low-force control task, involving the thumb-index grip, does affect the corticospinal excitability to the thumb-index muscles and the activation of the motor cortices, primary and non-primary (supplementary motor area, dorsal and ventral premotor and in the contralateral area), at the origin of the CS. With transcranial magnetic stimulation, we showed that, when precision demands increased, the CS excitability increased to either the first dorsal interosseus or the opponens pollicis, and never to both, for similar ongoing electromyographic activation patterns of these muscles. With functional magnetic resonance imagery, we demonstrated that, for the same averaged force level, the amplitude of blood oxygen level-dependent signal increased in relation to the precision demands in the hand area of the contralateral primary motor cortex in the contralateral supplementary motor area, ventral and dorsal premotor area. Together these results show that, during the course of force generation, the CS integrates online top-down information to precisely fit the motor output to the task's constraints and that its multiple cortical origins are involved in this process, with the ventral premotor area appearing to have a special role.

The role of oscillatory brain activity in object processing and figure-ground segmentation in human vision.

PubMed

Kinsey, K; Anderson, S J; Hadjipapas, A; Holliday, I E

2011-03-01

The perception of an object as a single entity within a visual scene requires that its features are bound together and segregated from the background and/or other objects. Here, we used magnetoencephalography (MEG) to assess the hypothesis that coherent percepts may arise from the synchronized high frequency (gamma) activity between neurons that code features of the same object. We also assessed the role of low frequency (alpha, beta) activity in object processing. The target stimulus (i.e. object) was a small patch of a concentric grating of 3c/°, viewed eccentrically. The background stimulus was either a blank field or a concentric grating of 3c/° periodicity, viewed centrally. With patterned backgrounds, the target stimulus emerged--through rotation about its own centre--as a circular subsection of the background. Data were acquired using a 275-channel whole-head MEG system and analyzed using Synthetic Aperture Magnetometry (SAM), which allows one to generate images of task-related cortical oscillatory power changes within specific frequency bands. Significant oscillatory activity across a broad range of frequencies was evident at the V1/V2 border, and subsequent analyses were based on a virtual electrode at this location. When the target was presented in isolation, we observed that: (i) contralateral stimulation yielded a sustained power increase in gamma activity; and (ii) both contra- and ipsilateral stimulation yielded near identical transient power changes in alpha (and beta) activity. When the target was presented against a patterned background, we observed that: (i) contralateral stimulation yielded an increase in high-gamma (>55 Hz) power together with a decrease in low-gamma (40-55 Hz) power; and (ii) both contra- and ipsilateral stimulation yielded a transient decrease in alpha (and beta) activity, though the reduction tended to be greatest for contralateral stimulation. The opposing power changes across different regions of the gamma spectrum with 'figure/ground' stimulation suggest a possible dual role for gamma rhythms in visual object coding, and provide general support of the binding-by-synchronization hypothesis. As the power changes in alpha and beta activity were largely independent of the spatial location of the target, however, we conclude that their role in object processing may relate principally to changes in visual attention. Copyright © 2010 Elsevier B.V. All rights reserved.

Laterality and unilateral deafness: Patients with congenital right ear deafness do not develop atypical language dominance.

PubMed

Van der Haegen, Lise; Acke, Frederic; Vingerhoets, Guy; Dhooge, Ingeborg; De Leenheer, Els; Cai, Qing; Brysbaert, Marc

2016-12-01

Auditory speech perception, speech production and reading lateralize to the left hemisphere in the majority of healthy right-handers. In this study, we investigated to what extent sensory input underlies the side of language dominance. We measured the lateralization of the three core subprocesses of language in patients who had profound hearing loss in the right ear from birth and in matched control subjects. They took part in a semantic decision listening task involving speech and sound stimuli (auditory perception), a word generation task (speech production) and a passive reading task (reading). The results show that a lack of sensory auditory input on the right side, which is strongly connected to the contralateral left hemisphere, does not lead to atypical lateralization of speech perception. Speech production and reading were also typically left lateralized in all but one patient, contradicting previous small scale studies. Other factors such as genetic constraints presumably overrule the role of sensory input in the development of (a)typical language lateralization. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spatiotemporal dynamics of auditory attention synchronize with speech

PubMed Central

Wöstmann, Malte; Herrmann, Björn; Maess, Burkhard

2016-01-01

Attention plays a fundamental role in selectively processing stimuli in our environment despite distraction. Spatial attention induces increasing and decreasing power of neural alpha oscillations (8–12 Hz) in brain regions ipsilateral and contralateral to the locus of attention, respectively. This study tested whether the hemispheric lateralization of alpha power codes not just the spatial location but also the temporal structure of the stimulus. Participants attended to spoken digits presented to one ear and ignored tightly synchronized distracting digits presented to the other ear. In the magnetoencephalogram, spatial attention induced lateralization of alpha power in parietal, but notably also in auditory cortical regions. This alpha power lateralization was not maintained steadily but fluctuated in synchrony with the speech rate and lagged the time course of low-frequency (1–5 Hz) sensory synchronization. Higher amplitude of alpha power modulation at the speech rate was predictive of a listener’s enhanced performance of stream-specific speech comprehension. Our findings demonstrate that alpha power lateralization is modulated in tune with the sensory input and acts as a spatiotemporal filter controlling the read-out of sensory content. PMID:27001861

Ipsi- and Contralateral Motor Response Using Ultrasound-induced Neurostimulation in Deeply Anesthetized Mice

NASA Astrophysics Data System (ADS)

Kamimura, Hermes; Wang, Shutao; Chen, Hong; Wang, Qi; Aurup, Christian; Fan, Kathtleen; Carneiro, Antonio; Konofagou, Elisa

Ultrasound neurostimulation has been proven capable of eliciting motor responses. However, the studies in sedated rodents presented problems with target specificity due to the use of low ultrasound frequencies (<700 kHz). Here, we show that focused ultrasound (FUS) in mega-Hz range was able to evoke motor responses in mice under deep anesthesia. Contralateral movements of the hind limbs were observed when sonications were carried out at +2 mm of Lambda and ±2 mm lateral of midline in three mice. Moreover, stimulating other regions of the somatosensory and cerebellum induced trunk and ipsilateral limb movements in all six mice.

Hemispheric Asymmetry of Visual Cortical Response by Means of Functional Transcranial Doppler

PubMed Central

Roje-Bedeković, Marina; Lovrenčić-Huzjan, Arijana; Bosnar-Puretić, Marijana; Šerić, Vesna; Demarin, Vida

2012-01-01

We assessed the visual evoked response and investigated side-to-side differences in mean blood flow velocities (MBFVs) by means of functional transcranial Doppler (fTCD) in 49 right-handed patients with severe internal carotid artery (ICA) stenosis and 30 healthy volunteers, simultaneously in both posterior cerebral arteries (PCAs) using 2 MHz probes, successively in the dark and during the white light stimulation. Statistically significant correlation (P = 0.001) was shown in healthy and in patients (P < 0.05) between MBFV in right PCA in physiological conditions and MBFV in right PCA during the white light stimulation and in the dark. The correlation between MBVF in right PCA and contralateral left PCA was not statistically significant (P > 0.05). The correlation between ipsilateral left PCA was significantly higher than the one with contralateral right PCA (P < 0.05). There is a clear trend towards the lateralisation of the visual evoked response in the right PCA. PMID:22135771

Inner ear test battery in guinea pig models - a review.

PubMed

Young, Yi-Ho

2018-06-01

This study reviewed the development of the inner ear test battery comprising auditory brainstem response (ABR), and caloric, ocular vestibular-evoked myogenic potential (oVEMP), and cervical vestibular-evoked myogenic potential (cVEMP) tests in guinea pig models at our laboratory over the last 20 years. Detailed description of the methodology for testing the small animals is also included. Inner ear disorders, i.e. ototoxicity, noise exposure, or perilymph fistula were established in guinea pig models first. One to four weeks after operation, each animal underwent ABR, oVEMP, cVEMP, and caloric tests. Then, animals were sacrificed for morphological study in the temporal bones. Inner ear endorgans can be comprehensively evaluated in guinea pig models via an inner ear test battery, which provides thorough information on the cochlea, saccule, utricle, and semicircular canal function of guinea pigs. Coupled with morphological study in the temporal bones of the animals may help elucidate the mechanism of inner ear disorders in humans. The inner ear test battery in guinea pig models may encourage young researchers to perform basic study in animals and stimulate the progress of experimental otology which is in evolution.

Pressure generation during neural stimulation with infrared radiation

NASA Astrophysics Data System (ADS)

Xia, N.; Tan, X.; Xu, Y.; Richter, C.-P.

2017-02-01

This study quantifies laser evoked pressure waves in small confined volumes such as a small dish or the cochlea. The pressure was measured with custom fabricated pressure probes in front of the optical fiber. For the pressure measurements during laser stimulation the probes were inserted into scala tympani or vestibuli. At 164 μJ/pulse, the intracochlear pressure was between 96 and 106 dB (re 20 μPa). The pressure was also measured in the ear canal with a sensitive microphone. It was on average 63 dB (re 20 μPa). At radiant energies large enough to evoke an auditory compound action potential, the outer ear canal equivalent pressure was 36-56 dB (re 20 μPa).

The Codacs™ Direct Acoustic Cochlear Implant Actuator: Exploring Alternative Stimulation Sites and Their Stimulation Efficiency

PubMed Central

Grossöhmichen, Martin; Salcher, Rolf; Kreipe, Hans-Heinrich; Lenarz, Thomas; Maier, Hannes

2015-01-01

This work assesses the efficiency of the Codacs system actuator (Cochlear Ltd., Sydney Australia) in different inner ear stimulation modalities. Originally the actuator was intended for direct perilymph stimulation after stapedotomy using a piston prosthesis. A possible alternative application is the stimulation of middle ear structures or the round window (RW). Here the perilymph stimulation with a K-piston through a stapes footplate (SFP) fenestration (N = 10) as well as stimulation of the stapes head (SH) with a Bell prosthesis (N = 9), SFP stimulation with an Omega/Aerial prosthesis (N = 8) and reverse RW stimulation (N = 10) were performed in cadaveric human temporal bones (TBs). Codacs actuator output is expressed as equivalent sound pressure level (eq. SPL) using RW and SFP displacement responses, measured by Laser Doppler velocimetry as reference. The axial actuator coupling force in stimulation of stapes and RW was adjusted to ~ 5 mN. The Bell prosthesis and Omega/Aerial prosthesis stimulation generated similar mean eq. SPLs (Bell: 127.5–141.8 eq. dB SPL; Omega/Aerial: 123.6–143.9 eq. dB SPL), being significantly more efficient than K-piston perilymph stimulation (108.6–131.6 eq. dB SPL) and RW stimulation (108.3–128.2 eq. dB SPL). Our results demonstrate that SH, SFP and RW are adequate alternative stimulation sites for the Codacs actuator using coupling prostheses and an axial coupling force of ~ 5 mN. Based on the eq. SPLs, all investigated methods were adequate for in vivo hearing aid applications, provided that experimental conditions including constant coupling force will be implemented. PMID:25785860

Neuronal Basis of Crossed Actions from the Reticular Formation on Feline Hindlimb Motoneurons

PubMed Central

Jankowska, Elzbieta; Hammar, Ingela; Slawinska, Urszula; Maleszak, Katarzyna; Edgley, Stephen A.

2007-01-01

Pathways through which reticulospinal neurons can influence contralateral limb movements were investigated by recording from mo-toneurons innervating hindlimb muscles. Reticulospinal tract fibers were stimulated within the brainstem or in the lateral funiculus of the thoracic spinal cord contralateral to the motoneurons. Effects evoked by ipsilaterally descending reticulospinal tract fibers were eliminated by a spinal hemisection at an upper lumbar level. Stimuli applied in the brainstem evoked EPSPs, IPSPs, or both at latencies of 1.42 ± 0.03 and 1.53 ± 0.04 msec, respectively, from the first components of the descending volleys and with properties indicating a disynaptic linkage, in most contralateral motoneurons: EPSPs in 76% and IPSPs in 26%. EPSPs with characteristics of monosynaptically evoked responses, attributable to direct actions of crossed axon collaterals of reticulospinal fibers, were found in a small proportion of the motoneurons, whether evoked from the brainstem (9%) or from the thoracic cord (12.5%). Commissural neurons, which might mediate the crossed disynaptic actions (i.e., were antidromically activated from contralateral motor nuclei and monosynaptically excited from the ipsilateral reticular formation), were found in Rexed’s lamina VIII in the midlumbar segments (L3–L5). The results reveal that although direct actions of reticulospinal fibers are much more potent on ipsilateral motoneurons, interneuronally mediated actions are as potent contralaterally as ipsilaterally, and midlumbar commissural neurons are likely to contribute to them. They indicate a close coupling between the spinal interneuronal systems used by the reticulospinal neurons to coordinate muscle contractions ipsilaterally and contralaterally. PMID:12629191

Anatomical physiology of spatial extinction.

PubMed

Ciçek, Metehan; Gitelman, Darren; Hurley, Robert S E; Nobre, Anna; Mesulam, Marsel

2007-12-01

Neurologically intact volunteers participated in a functional magnetic resonance imaging experiment that simulated the unilateral (focal) and bilateral (global) stimulations used to elicit extinction in patients with hemispatial neglect. In peristriate areas, attentional modulations were selectively sensitive to contralaterally directed attention. A higher level of mapping was observed in the intraparietal sulcus (IPS), inferior parietal lobule (IPL), and inferior frontal gyrus (IFG). In these areas, there was no distinction between contralateral and ipsilateral focal attention, and the need to distribute attention globally led to greater activity than either focal condition. These physiological characteristics were symmetrically distributed in the IPS and IFG, suggesting that the effects of unilateral lesions in these 2 areas can be compensated by the contralateral hemisphere. In the IPL, the greater activation by the bilateral attentional mode was seen only in the right hemisphere. Its contralateral counterpart displayed equivalent activations when attention was distributed to the right, to the left, or bilaterally. Within the context of this experiment, the IPL of the right hemisphere emerged as the one area where unilateral lesions can cause the most uncompensated and selective impairment of global attention (without interfering with unilateral attention to either side), giving rise to the phenomenon of extinction.

Cathodal transcranial direct current stimulation in children with dystonia: a sham-controlled study.

PubMed

Young, Scott J; Bertucco, Matteo; Sanger, Terence D

2014-02-01

Increased motor cortex excitability is a common finding in dystonia, and transcranial direct current stimulation can reduce motor cortex excitability. In an earlier study, we found that cathodal direct-current stimulation decreased motor overflow for some children with dystonia. To investigate this observation further, we performed a sham-controlled, double-blind, crossover study of 14 children with dystonia. We found a significant reduction in overflow following real stimulation, when participants performed the experimental task with the hand contralateral to the cathode. While these results suggest that cathodal stimulation may help some children to reduce involuntary overflow, the size of the effect is small. Further research will need to investigate ways to increase the magnitude of the effect of cathodal transcranial direct current stimulation.

Anti-inflammatory activity of standardized dichloromethane extract of Salvia connivens on macrophages stimulated by LPS.

PubMed

González-Chávez, Marco Martín; Ramos-Velázquez, Cinthia Saraí; Serrano-Vega, Roberto; Pérez-González, Cuauhtemoc; Sánchez-Mendoza, Ernesto; Pérez-Gutiérrez, Salud

2017-12-01

A previous study demonstrated that the chloroform extract of Salvia connivens Epling (Lamiaceae) has anti-inflammatory activity. Identification of the active components in the dicholorometane extract (DESC), and, standardization of the extract based in ursolic acid. DESC was prepared by percolation with dichlromethane and after washed with hot hexane, its composition was determined by CG-MS and NMR, and standardized by HPLC. The anti-inflammatory activity was tested on acute TPA-induced mouse ear oedema at doses of 2.0 mg/ear. The cell viability of macrophages was evaluated by MTT method, and pro- and anti-inflammatory interleukin levels were measured using an ELISA kit. Ursolic acid, oleanolic acid, dihydroursolic acid and eupatorin were identified in DESC, which was standardized based on the ursolic acid concentration (126 mg/g). The anti-inflammatory activities of DESC, the acid mixture, and eupatorin (2 mg/ear) were 60.55, 57.20 and 56.40% inhibition, respectively, on TPA-induced ear oedema. The IC 50 of DESC on macrophages was 149.4 μg/mL. DESC (25 μg/mL) significantly reduced TNF-α (2.0-fold), IL-1β (2.2-fold) and IL-6 (2.0-fold) in macrophages stimulated with LPS and increased the production of IL-10 (1.9-fold). Inflammation is a basic response to injuries, and macrophages are involved in triggering inflammation. Macrophage cells exhibit a response to LPS, inducing inflammatory mediators, and DESC inhibits the biosynthesis of the pro-inflammatory and promote anti-inflammatory cytokines. DESC has an anti-inflammatory effect; reduced the levels of IL-1β, Il-6 and TNF-α; and increases IL-10 in macrophages stimulated with LPS. Ursolic acid is a good phytochemical marker.

Anti-inflammatory effect of ethanolic extract from Myagropsis myagroides on murine macrophages and mouse ear edema

PubMed Central

2012-01-01

Background This study aims to investigate anti-inflammatory effect of ethanolic extract of Myagropsis myagroides (EMM) in the lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and the phorbol 12-myristate 13-acetate (PMA)-induced ear edema in mice, and to clarify its underlying molecular mechanisms. Methods The levels of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines were measured by Griess assay and enzyme linked immunosorbent assay. The expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), mitogen-activated protein kinases (MAPKs), and Akt were measured using Western blotting. Nuclear translocation and transcriptional activation of nuclear factor-κB (NF-κB) were determined by immunocytochemistry and reporter gene assay, respectively. PMA-induced mouse ear edema was used as the animal model of inflammation. Anti-inflammatory compounds in EMM were isolated using high-performance liquid chromatography and identified by nuclear magnetic resonance. Results EMM significantly inhibited the production of NO, PGE2, and pro-inflammatory cytokines in a dose-dependent manner and suppressed the expression of iNOS and COX-2 in LPS-stimulated RAW 264.7 cells. EMM strongly suppressed nuclear translocation of NF-κB by preventing degradation of inhibitor of κB-α as well as by inhibiting phosphorylation of Akt and MAPKs. EMM reduced ear edema in PMA-induced mice. One of the anti-inflammatory compounds in EMM was identified as 6,6’-bieckol. Conclusions These results suggest that the anti-inflammatory properties of EMM are associated with the down-regulation of iNOS, COX-2, and pro-inflammatory cytokines through the inhibition of NF-κB pathway in LPS-stimulated macrophages. PMID:23031211

The Effects of Acoustic Bandwidth on Simulated Bimodal Benefit in Children and Adults with Normal Hearing.

PubMed

Sheffield, Sterling W; Simha, Michelle; Jahn, Kelly N; Gifford, René H

2016-01-01

The primary purpose of this study was to examine the effect of acoustic bandwidth on bimodal benefit for speech recognition in normal-hearing children with a cochlear implant (CI) simulation in one ear and low-pass filtered stimuli in the contralateral ear. The effect of acoustic bandwidth on bimodal benefit in children was compared with the pattern of adults with normal hearing. Our hypothesis was that children would require a wider acoustic bandwidth than adults to (1) derive bimodal benefit, and (2) obtain asymptotic bimodal benefit. Nineteen children (6 to 12 years) and 10 adults with normal hearing participated in the study. Speech recognition was assessed via recorded sentences presented in a 20-talker babble. The AzBio female-talker sentences were used for the adults and the pediatric AzBio sentences (BabyBio) were used for the children. A CI simulation was presented to the right ear and low-pass filtered stimuli were presented to the left ear with the following cutoff frequencies: 250, 500, 750, 1000, and 1500 Hz. The primary findings were (1) adults achieved higher performance than children when presented with only low-pass filtered acoustic stimuli, (2) adults and children performed similarly in all the simulated CI and bimodal conditions, (3) children gained significant bimodal benefit with the addition of low-pass filtered speech at 250 Hz, and (4) unlike previous studies completed with adult bimodal patients, adults and children with normal hearing gained additional significant bimodal benefit with cutoff frequencies up to 1500 Hz with most of the additional benefit gained with energy below 750 Hz. Acoustic bandwidth effects on simulated bimodal benefit were similar in children and adults with normal hearing. Should the current results generalize to children with CIs, these results suggest pediatric CI recipients may derive significant benefit from minimal acoustic hearing (<250 Hz) in the nonimplanted ear and increasing benefit with broader bandwidth. Knowledge of the effect of acoustic bandwidth on bimodal benefit in children may help direct clinical decisions regarding a second CI, continued bimodal hearing, and even optimizing acoustic amplification for the nonimplanted ear.

The effect of stimulus intensity on the right ear advantage in dichotic listening.

PubMed

Hugdahl, Kenneth; Westerhausen, René; Alho, Kimmo; Medvedev, Svyatoslav; Hämäläinen, Heikki

2008-01-24

The dichotic listening test is non-invasive behavioural technique to study brain lateralization and it has been shown, that its results can be systematically modulated by varying stimulation properties (bottom-up effects) or attentional instructions (top-down effects) of the testing procedure. The goal of the present study was to further investigate the bottom-up modulation, by examining the effect of differences in the right or left ear stimulus intensity on the ear advantage. For this purpose, interaural intensity difference were gradually varied in steps of 3 dB from -21 dB in favour of the left ear to +21 dB in favour of the right ear, also including a no difference baseline condition. Thirty-three right-handed adult participants with normal hearing acuity were tested. The dichotic listening paradigm was based on consonant-vowel stimuli pairs. Only pairs with the same voicing (voice or non-voiced) of the consonant sound were used. The results showed: (a) a significant right ear advantage (REA) for interaural intensity differences from 21 to -3 dB, (b) no ear advantage (NEA) for the -6 dB difference, and (c) a significant left ear advantage (LEA) for differences form -9 to -21 dB. It is concluded that the right ear advantage in dichotic listening to CV syllables withstands an interaural intensity difference of -9 dB before yielding to a significant left ear advantage. This finding could have implications for theories of auditory laterality and hemispheric asymmetry for phonological processing.

Subjective and objective outcomes from new BiCROS technology in a veteran sample.

PubMed

Williams, Victoria A; McArdle, Rachel A; Chisolm, Theresa H

2012-01-01

Patients with single-sided deafness (SSD), where one ear has an unaidable hearing loss and the other ear has normal or aidable hearing, often complain of difficulties understanding speech and localizing sound sources, and report a higher self-perceived hearing disability. Patients with SSD may benefit from using contralateral routing of signal (CROS) or bilateral contralateral routing of the signal (BiCROS) amplification. Dissatisfaction of previously available (Bi)CROS devices has been reported, such as, interfering transmissions, low-fidelity sound quality, poor "user-friendly" set-up, and a bulky and cosmetically cumbersome appearance. Recent advances in hearing aid technology have improved (Bi)CROS hearing aids; however, these devices have not been experimentally evaluated. We hypothesized that newer technology with reports of improved digital signal processing, wireless transmission, and physical design would be as good, or better than, our participants' previous-generation BiCROS systems. A within-subjects, pretest-posttest design was executed. Thirty-nine veterans (one female, 38 males; mean age = 74 yr, range = 49-85 yr) from the Audiology Section of the Bay Pines Veterans Affair Healthcare System participated. All participants were previously experienced BiCROS hearing aid users with varying degrees of sensorinerual hearing impairment in their better ear. Participants were provided at least 4 wk of consistent use with the new BiCROS. DATA COLLECTION AND ANALYSES: Participants completed three research visits. At Visit 1, with their previous BiCROS, and at Visit 3, with their new BiCROS, the following objective and subjective measures were obtained: (1) soundfield speech-in-noise testing using the Words-In-Noise (WIN) test; (2) speech, spatial, and qualities of the hearing scale (SSQ) questionnaire; (3) selected questions from the MarkeTrak questionnaire; and, (4) three open-ended questions. Data were analyzed using parametric and nonparametric statistics. Overall, the objective (WIN) and subjective (SSQ, MarkeTrak, and open-ended questions) measures indicated that the new BiCROS provided better outcomes than the previous BiCROS system. In addition, an overlap of favorable results was seen across measures. Of the 39 participants, 95% reported improvements with the new BiCROS and chose to utilize the device regularly. The favorable objective and subjective outcomes indicate that the new BiCROS system is as good, or better than, what was previously utilized by our sample of veterans. American Academy of Audiology.

Brain activations evoked by tactile stimulation varies with the intensity and not with number of receptive fields stimulated: An fMRI study

NASA Astrophysics Data System (ADS)

Ramirez Garzón, Y. T.; Pasaye, E. H.; Barrios, F. A.

2014-11-01

Using functional Magnetic Resonance Imaging (fMRI) it is possible to study the functional anatomy of primary cortices. Cortical representations in the primary somatosensory cortex have shown discrepancies between activations related to the same body region in some studies; these differences have been more pronounced for lower limb representations. The aim of this study was to observe the influence of the tactile stimulus intensity in somatosensory cortical responses using fMRI. Based in the sensitivity and pain threshold of each subject, we used Von Frey filaments for stimulate 12 control subject in three receptive fields on the right thigh. One filament near to sensitivity threshold (VFS), other close to pain threshold (VFP) and one intermediate filament between the two previous thresholds (VFI). The tactile stimulation with VFS produced no activation on SI, while that the contralateral SI was activated by stimulation with VFI in 5 subjects and with the stimulation of VFP in all subjects. Second level statistical analysis showed significant differences between SI activations related to the stimulation with VFP and VFI (VFP > VFI), in the comparison between the applied different intensities, a small cluster of activation was observed on SI for the unique possible contrast (VFP > VFI). The time course per trial for each subject was extracted and averaged to extract the activation in the contralateral SI and compared across the stimulus modalities, between the sites of field receptive stimulated and the intensities used. The time course of tactile stimulus responses revealed a consistent single peak of activity per cycle (30 s), approximately 12 s after the onset of the stimulus, with exception of the VFI stimulation,_which showed the peak at 10 s. Thus, our results indicate that the cortical representation of a tactile stimulus with fMRI is modulated for the intensity of the stimulus applied.

A Retrospective Multicentre Cohort Review of Patient Characteristics and Surgical Aspects versus the Long-Term Outcomes for Recipients of a Fully Implantable Active Middle Ear Implant

PubMed Central

Lefebvre, Philippe P.; Gisbert, Javier; Cuda, Domenico; Tringali, Stéphane; Deveze, Arnaud

2017-01-01

Objective To summarise treatment outcomes compared to surgical and patient variables for a multicentre recipient cohort using a fully implantable active middle ear implant for hearing impairment. To describe the authors' preferred surgical technique to determine microphone placement. Study Design Multicentre retrospective, observational survey. Setting Five tertiary referral centres. Patients Carina recipients (66 ears, 62 subjects) using the current Cochlear® Carina® System or the legacy device, the Otologics® Fully Implantable Middle Ear, with a T2 transducer. Methods Patient file review and routine clinical review. Patient outcomes assessed were satisfaction, daily use and feedback reports at the first fitting and ≥12 months after implantation. Descriptive and statistical analysis of correlations of variables and their influence on outcomes was performed. Independently reported preferred methods for microphone placement are collectively summarised. Results The average implant experience was 3.5 years. Satisfaction increased significantly over time (p < 0.05). No correlation with covariates examined was observed. Feedback significantly decreased over time, showing a significant correlation with microphone location, primary motivation, gender, age at implantation, and contralateral hearing aid use (p < 0.05). Patient satisfaction was inversely correlated with reports of system feedback (p < 0.05). The implantable microphone was most commonly on the posterior inferior mastoid line, in 42/66 (65%) cases, correlating with less likelihood for feedback and consistent with author surgical preference. Conclusion Carina recipients in this study present as satisfied consistent daily users with very few reports of persistent feedback. As microphone location is an influencing factor, a careful surgical consideration of microphone placement is required. The authors prefer a posterior inferior mastoid line position whenever possible. PMID:28052264

Stimulus change detection in phasic auditory units in the frog midbrain: frequency and ear specific adaptation.

PubMed

Ponnath, Abhilash; Hoke, Kim L; Farris, Hamilton E

2013-04-01

Neural adaptation, a reduction in the response to a maintained stimulus, is an important mechanism for detecting stimulus change. Contributing to change detection is the fact that adaptation is often stimulus specific: adaptation to a particular stimulus reduces excitability to a specific subset of stimuli, while the ability to respond to other stimuli is unaffected. Phasic cells (e.g., cells responding to stimulus onset) are good candidates for detecting the most rapid changes in natural auditory scenes, as they exhibit fast and complete adaptation to an initial stimulus presentation. We made recordings of single phasic auditory units in the frog midbrain to determine if adaptation was specific to stimulus frequency and ear of input. In response to an instantaneous frequency step in a tone, 28% of phasic cells exhibited frequency specific adaptation based on a relative frequency change (delta-f=±16%). Frequency specific adaptation was not limited to frequency steps, however, as adaptation was also overcome during continuous frequency modulated stimuli and in response to spectral transients interrupting tones. The results suggest that adaptation is separated for peripheral (e.g., frequency) channels. This was tested directly using dichotic stimuli. In 45% of binaural phasic units, adaptation was ear specific: adaptation to stimulation of one ear did not affect responses to stimulation of the other ear. Thus, adaptation exhibited specificity for stimulus frequency and lateralization at the level of the midbrain. This mechanism could be employed to detect rapid stimulus change within and between sound sources in complex acoustic environments.

Stimulus change detection in phasic auditory units in the frog midbrain: frequency and ear specific adaptation

PubMed Central

Ponnath, Abhilash; Hoke, Kim L.

2013-01-01

Neural adaptation, a reduction in the response to a maintained stimulus, is an important mechanism for detecting stimulus change. Contributing to change detection is the fact that adaptation is often stimulus specific: adaptation to a particular stimulus reduces excitability to a specific subset of stimuli, while the ability to respond to other stimuli is unaffected. Phasic cells (e.g., cells responding to stimulus onset) are good candidates for detecting the most rapid changes in natural auditory scenes, as they exhibit fast and complete adaptation to an initial stimulus presentation. We made recordings of single phasic auditory units in the frog midbrain to determine if adaptation was specific to stimulus frequency and ear of input. In response to an instantaneous frequency step in a tone, 28 % of phasic cells exhibited frequency specific adaptation based on a relative frequency change (delta-f = ±16 %). Frequency specific adaptation was not limited to frequency steps, however, as adaptation was also overcome during continuous frequency modulated stimuli and in response to spectral transients interrupting tones. The results suggest that adaptation is separated for peripheral (e.g., frequency) channels. This was tested directly using dichotic stimuli. In 45 % of binaural phasic units, adaptation was ear specific: adaptation to stimulation of one ear did not affect responses to stimulation of the other ear. Thus, adaptation exhibited specificity for stimulus frequency and lateralization at the level of the midbrain. This mechanism could be employed to detect rapid stimulus change within and between sound sources in complex acoustic environments. PMID:23344947

The Relationship Between Intensity Coding and Binaural Sensitivity in Adults With Cochlear Implants.

PubMed

Todd, Ann E; Goupell, Matthew J; Litovsky, Ruth Y

Many bilateral cochlear implant users show sensitivity to binaural information when stimulation is provided using a pair of synchronized electrodes. However, there is large variability in binaural sensitivity between and within participants across stimulation sites in the cochlea. It was hypothesized that within-participant variability in binaural sensitivity is in part affected by limitations and characteristics of the auditory periphery which may be reflected by monaural hearing performance. The objective of this study was to examine the relationship between monaural and binaural hearing performance within participants with bilateral cochlear implants. Binaural measures included dichotic signal detection and interaural time difference discrimination thresholds. Diotic signal detection thresholds were also measured. Monaural measures included dynamic range and amplitude modulation detection. In addition, loudness growth was compared between ears. Measures were made at three stimulation sites per listener. Greater binaural sensitivity was found with larger dynamic ranges. Poorer interaural time difference discrimination was found with larger difference between comfortable levels of the two ears. In addition, poorer diotic signal detection thresholds were found with larger differences between the dynamic ranges of the two ears. No relationship was found between amplitude modulation detection thresholds or symmetry of loudness growth and the binaural measures. The results suggest that some of the variability in binaural hearing performance within listeners across stimulation sites can be explained by factors nonspecific to binaural processing. The results are consistent with the idea that dynamic range and comfortable levels relate to peripheral neural survival and the width of the excitation pattern which could affect the fidelity with which central binaural nuclei process bilateral inputs.

Detection of Interaural Time Differences in the Alligator

PubMed Central

Carr, Catherine E.; Soares, Daphne; Smolders, Jean; Simon, Jonathan Z.

2011-01-01

The auditory systems of birds and mammals use timing information from each ear to detect interaural time difference (ITD). To determine whether the Jeffress-type algorithms that underlie sensitivity to ITD in birds are an evolutionarily stable strategy, we recorded from the auditory nuclei of crocodilians, who are the sister group to the birds. In alligators, precisely timed spikes in the first-order nucleus magnocellularis (NM) encode the timing of sounds, and NM neurons project to neurons in the nucleus laminaris (NL) that detect interaural time differences. In vivo recordings from NL neurons show that the arrival time of phase-locked spikes differs between the ipsilateral and contralateral inputs. When this disparity is nullified by their best ITD, the neurons respond maximally. Thus NL neurons act as coincidence detectors. A biologically detailed model of NL with alligator parameters discriminated ITDs up to 1 kHz. The range of best ITDs represented in NL was much larger than in birds, however, and extended from 0 to 1000 μs contralateral, with a median ITD of 450 μs. Thus, crocodilians and birds employ similar algorithms for ITD detection, although crocodilians have larger heads. PMID:19553438

The Benefits of Bimodal Aiding on Extended Dimensions of Speech Perception: Intelligibility, Listening Effort, and Sound Quality

PubMed Central

Chalupper, Josef

2017-01-01

The benefits of combining a cochlear implant (CI) and a hearing aid (HA) in opposite ears on speech perception were examined in 15 adult unilateral CI recipients who regularly use a contralateral HA. A within-subjects design was carried out to assess speech intelligibility testing, listening effort ratings, and a sound quality questionnaire for the conditions CI alone, CIHA together, and HA alone when applicable. The primary outcome of bimodal benefit, defined as the difference between CIHA and CI, was statistically significant for speech intelligibility in quiet as well as for intelligibility in noise across tested spatial conditions. A reduction in effort on top of intelligibility at the highest tested signal-to-noise ratio was found. Moreover, the bimodal listening situation was rated to sound more voluminous, less tinny, and less unpleasant than CI alone. Listening effort and sound quality emerged as feasible and relevant measures to demonstrate bimodal benefit across a clinically representative range of bimodal users. These extended dimensions of speech perception can shed more light on the array of benefits provided by complementing a CI with a contralateral HA. PMID:28874096

AN INVESTIGATION OF DIFFERENTIAL BINAURAL STIMULATION IN THE TEACHING OF A FOREIGN LANGUAGE.

ERIC Educational Resources Information Center

VAN RIPER, CHARLES

THIS STUDY DETERMINED WHETHER OR NOT DIFFERENTIAL BINAURAL STIMULATIONS CAN BE USED EFFECTIVELY TO IMPROVE PRONUNCIATION IN FOREIGN LANGUAGE TEACHING. THE OBJECTIVE WAS TO DETERMINE WHAT EFFECT HEARING SIMULTANEOUSLY THE TEACHER'S VOICE IN ONE EAR AND HIS OWN VOICE IN THE OTHER WOULD HAVE ON A STUDENT'S ABILITY TO COMPARE THE DIFFERENCES IN…

[Effect of the middle ear status on the recording of vestibular evoked myogenic potential--VEMP].

PubMed

Kurzyna, Agnieszka; Hassmann-Poznańska, Elzbieta; Topolska, Małgorzata Maria

2004-01-01

The aim of this study was to assess the effect of age on the recording of air- and bone-conducted vestibular evoked myogenic potential. Forty six young subjects were included in the study, ranging in age from 4 to 18 years. All of them underwent otoscopy, pure tone audiometry, tympanometry and air- and bone-conducted VEMP in response to click. Eighty six ears with normal hearing (pure tone average 20 dB) and type A and C1 tympanogram were studied. There were 2 groups according to age: group I--children aged 4-10 years--52 ears, group II--young subjects aged 11-18 years--34 ears. The threshold, the presence of correct waveform morphology of the response and the latency were evaluated. Above parameters were examined at 95 dB and 100 dB (nHL) air conducted click intensity and 60 dB (nHL) bone conducted click intensity. The age has no significant effect on the percentage of the recording of VEMP and the level of the response threshold with air stimulation, based on the performed studies. However, the age has effect on the prolongation of latency p13 and n23 both with air and bone stimulation. We paid attention to the lower percentage of the recording of bone-conducted VEMP in young subjects aged 11-18 years.

Intermittent θ burst stimulation over primary motor cortex enhances movement-related β synchronisation.

PubMed

Hsu, Ya-Fang; Liao, Kwong-Kum; Lee, Po-Lei; Tsai, Yun-An; Yeh, Chia-Lung; Lai, Kuan-Lin; Huang, Ying-Zu; Lin, Yung-Yang; Lee, I-Hui

2011-11-01

The objective of this study is to investigate how transcranial magnetic intermittent theta burst stimulation (iTBS) with a prolonged protocol affects human cortical excitability and movement-related oscillations. Using motor-evoked potentials (MEPs) and movement-related magnetoencephalography (MEG), we assessed the changes of corticospinal excitability and cortical oscillations after iTBS with double the conventional stimulation time (1200 pulses, iTBS1200) over the primary motor cortex (M1) in 10 healthy subjects. Continuous TBS (cTBS1200) and sham stimulation served as controls. iTBS1200 facilitated MEPs evoked from the conditioned M1, while inhibiting MEPs from the contralateral M1 for 30 min. By contrast, cTBS1200 inhibited MEPs from the conditioned M1. Importantly, empirical mode decomposition-based MEG analysis showed that the amplitude of post-movement beta synchronisation (16-26 Hz) was significantly increased by iTBS1200 at the conditioned M1, but was suppressed at the nonconditioned M1. Alpha (8-13 Hz) and low gamma-ranged (35-45 Hz) rhythms were not notably affected. Movement kinetics remained consistent throughout. TBS1200 modulated corticospinal excitability in parallel with the direction of conventional paradigms with modestly prolonged efficacy. Moreover, iTBS1200 increased post-movement beta synchronisation of the stimulated M1, and decreased that of the contralateral M1, probably through interhemispheric interaction. Our results provide insight into the underlying mechanism of TBS and reinforce the connection between movement-related beta synchronisation and corticospinal output. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Clinical evaluation of the vector algorithm for neonatal hearing screening using automated auditory brainstem response.

PubMed

Keohane, Bernie M; Mason, Steve M; Baguley, David M

2004-02-01

A novel auditory brainstem response (ABR) detection and scoring algorithm, entitled the Vector algorithm is described. An independent clinical evaluation of the algorithm using 464 tests (120 non-stimulated and 344 stimulated tests) on 60 infants, with a mean age of approximately 6.5 weeks, estimated test sensitivity greater than 0.99 and test specificity at 0.87 for one test. Specificity was estimated to be greater than 0.95 for a two stage screen. Test times were of the order of 1.5 minutes per ear for detection of an ABR and 4.5 minutes per ear in the absence of a clear response. The Vector algorithm is commercially available for both automated screening and threshold estimation in hearing screening devices.

Evaluation of muscle hyperactivity of the grimacing muscles by unilateral tight eyelid closure and stapedius muscle tone.

PubMed

Shiba, Masato; Matsuo, Kiyoshi; Ban, Ryokuya; Nagai, Fumio

2012-10-01

Muscle hyperactivity of grimacing muscles, including the orbicularis oculi and corrugator supercilii muscles that cause crow's feet and a glabellar frown line with ageing, cannot be accurately evaluated by surface observation. In 71 subjects, this study investigated the extent to which grimacing muscles are innervated by the bilateral motor cortices, whether the corticofacial projection to the grimacing muscles affects the facially innervated stapedius muscle tone by measuring static compliance of the tympanic membrane, and whether unilateral tight eyelid closure with contraction of the grimacing muscles changes static compliance. Unilateral tight eyelid closure and its subsequent change in the contralateral vertical medial eyebrow position revealed that motor neurons of the orbicularis oculi and corrugator supercilii muscles were innervated by the bilateral motor cortices with weak-to-strong contralateral dominance. The orbicularis oculi, corrugator supercilii, and stapedius muscles innervated by the bilateral motor cortices had increased muscle hyperactivity, which lowered the vertical medial eyebrow position and decreased the static compliance of the tympanic membrane more than those innervated by the unilateral motor cortex. Unilateral enhanced tight eyelid closure with contraction of the grimacing muscles in certain subjects ipsilaterally decreased the static compliance with increased contraction of the stapedius muscle, which probably occurs to immobilise the tympanic membrane and protect the inner ear from loud sound. Evaluation of unilateral tight eyelid closure and the subsequent change in the contralateral vertical medial eyebrow position as well as a measurement of the static compliance for the stapedius muscle tone has revealed muscle hyperactivity of grimacing muscles.

Sound pressure distribution and power flow within the gerbil ear canal from 100 Hz to 80 kHz

PubMed Central

Ravicz, Michael E.; Olson, Elizabeth S.; Rosowski, John J.

2008-01-01

Sound pressure was mapped in the bony ear canal of gerbils during closed-field sound stimulation at frequencies from 0.1 to 80 kHz. A 1.27-mm-diam probe-tube microphone or a 0.17-mm-diam fiber-optic miniature microphone was positioned along approximately longitudinal trajectories within the 2.3-mm-diam ear canal. Substantial spatial variations in sound pressure, sharp minima in magnitude, and half-cycle phase changes occurred at frequencies >30 kHz. The sound frequencies of these transitions increased with decreasing distance from the tympanic membrane (TM). Sound pressure measured orthogonally across the surface of the TM showed only small variations at frequencies below 60 kHz. Hence, the ear canal sound field can be described fairly well as a one-dimensional standing wave pattern. Ear-canal power reflectance estimated from longitudinal spatial variations was roughly constant at 0.2–0.5 at frequencies between 30 and 45 kHz. In contrast, reflectance increased at higher frequencies to at least 0.8 above 60 kHz. Sound pressure was also mapped in a microphone-terminated uniform tube—an “artificial ear.” Comparison with ear canal sound fields suggests that an artificial ear or “artificial cavity calibration” technique may underestimate the in situ sound pressure by 5–15 dB between 40 and 60 kHz. PMID:17902852

Surgical and Technical Modalities for Hearing Restoration in Ear Malformations.

PubMed

Dazert, Stefan; Thomas, Jan Peter; Volkenstein, Stefan

2015-12-01

Malformations of the external and middle ear often go along with an aesthetic and functional handicap. Independent of additional aesthetic procedures, a successful functional hearing restoration leads to a tremendous gain in quality of life for affected patients. The introduction of implantable hearing systems (bone conduction and middle ear devices) offers new therapeutic options in this field. We focus on functional rehabilitation of patients with malformations, either by surgical reconstruction or the use of different implantable hearing devices, depending on the disease itself and the severity of malformation as well as hearing impairment. Patients with an open ear canal and minor malformations are good candidates for surgical hearing restoration of middle ear structures with passive titanium or autologous implants. In cases with complete fibrous or bony atresia of the ear canal, the most promising functional outcome and gain in quality of life can be expected with an active middle ear implant or a bone conduction device combined with a surgical aesthetic rehabilitation in a single or multi-step procedure. Although the surgical procedure for bone conduction devices is straightforward and safe, more sophisticated operations for active middle ear implants (e.g., Vibrant Soundbridge, MED-EL, Innsbruck, Austria) provide an improved speech discrimination in noise and the ability of sound localization compared with bone conduction devices where the stimulation reaches both cochleae. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Increases in both cerebral glucose utilization and blood flow during execution of a somatosensory task.

PubMed

Ginsberg, M D; Chang, J Y; Kelley, R E; Yoshii, F; Barker, W W; Ingenito, G; Boothe, T E

1988-02-01

To investigate local metabolic and hemodynamic interrelationships during functional activation of the brain, paired studies of local cerebral glucose utilization (lCMRGlc) and blood flow (lCBF) were carried out in 10 normal subjects (9 right-handed, 1 ambidextrous) at rest and during a unilateral discriminative somatosensory/motor task--palpation and sorting of mah-jongg tiles by engraved design. The extent of activation was assessed on the basis of percentage difference images following normalization to compensate for global shifts. The somatosensory stimulus elevated lCMRGlc by 16.9 +/- 3.5% (mean +/- standard deviation) and lCBF by 26.5 +/- 5.1% in the contralateral sensorimotor cortical focus; smaller increments were noted in the homologous ipsilateral site. The increments of lCMRGlc and lCBF correlated poorly with one another in individual subjects. Stimulation of the right hand resulted in significantly higher contralateral lCMRGlc activation (19.6%) than did stimulation of the left hand (14.1%) (p less than 0.005), whereas the lCBF response was independent of the hand stimulated. Our results indicate that both glycolytic metabolism and blood flow increase locally with the execution of an active sensorimotor task and suggest that both measures may serve as reliable markers of functional activation of the normal brain.

Aging changes and gender differences in response to median nerve stimulation measured with MEG.

PubMed

Stephen, Julia M; Ranken, Doug; Best, Elaine; Adair, John; Knoefel, Janice; Kovacevic, Sanja; Padilla, Denise; Hart, Blaine; Aine, Cheryl J

2006-01-01

The current study uses magnetoencephalography (MEG) to characterize age-related changes and gender differences in the amplitudes and timing of cortical sources evoked by median nerve stimulation. Thirty-four healthy subjects from two age groups: 20-29 and >64 years of age were examined. After measuring the MEG responses, we modeled the data using a spatio-temporal multi-dipole modeling approach to determine the source locations and their associated timecourses. We found early, large amplitude responses in the elderly in primary somatosensory (approximately 20 ms) and pre-central sulcus timecourses (approximately 22 ms) and lower amplitude responses in the elderly later in primary somatosensory (approximately 32 ms) and contralateral secondary somatosensory timecourses (approximately 90 ms). In addition, females had larger peak amplitude responses than males in the contralateral secondary somatosensory timecourse (approximately 28 and 51 ms). These results show that the median nerve stimulation paradigm provides considerable sensitivity to age- and gender-related differences. The results are consistent with the theory that increased amplitudes identified in the elderly may be associated with decreased inhibition. The results emphasize that an examination of two discrete age groups, collapsed across gender, cannot provide a complete understanding of the fundamental changes that occur in the brain across the lifetime.

Long-Term Asymmetric Hearing Affects Cochlear Implantation Outcomes Differently in Adults with Pre- and Postlingual Hearing Loss

PubMed Central

Boisvert, Isabelle; McMahon, Catherine M.; Dowell, Richard C.; Lyxell, Björn

2015-01-01

In many countries, a single cochlear implant is offered as a treatment for a bilateral hearing loss. In cases where there is asymmetry in the amount of sound deprivation between the ears, there is a dilemma in choosing which ear should be implanted. In many clinics, the choice of ear has been guided by an assumption that the reorganisation of the auditory pathways caused by longer duration of deafness in one ear is associated with poorer implantation outcomes for that ear. This assumption, however, is mainly derived from studies of early childhood deafness. This study compared outcomes following implantation of the better or poorer ear in cases of long-term hearing asymmetries. Audiological records of 146 adults with bilateral hearing loss using a single hearing aid were reviewed. The unaided ear had 15 to 72 years of unaided severe to profound hearing loss before unilateral cochlear implantation. 98 received the implant in their long-term sound-deprived ear. A multiple regression analysis was conducted to assess the relative contribution of potential predictors to speech recognition performance after implantation. Duration of bilateral significant hearing loss and the presence of a prelingual hearing loss explained the majority of variance in speech recognition performance following cochlear implantation. For participants with postlingual hearing loss, similar outcomes were obtained by implanting either ear. With prelingual hearing loss, poorer outcomes were obtained when implanting the long-term sound-deprived ear, but the duration of the sound deprivation in the implanted ear did not reliably predict outcomes. Contrary to an apparent clinical consensus, duration of sound deprivation in one ear has limited value in predicting speech recognition outcomes of cochlear implantation in that ear. Outcomes of cochlear implantation are more closely related to the period of time for which the brain is deprived of auditory stimulation from both ears. PMID:26043227

Assessment of Ipsilateral Efferent Effects in Human via ECochG

PubMed Central

Verschooten, Eric; Strickland, Elizabeth A.; Verhaert, Nicolas; Joris, Philip X.

2017-01-01

Development of electrophysiological means to assess the medial olivocochlear (MOC) system in humans is important to further our understanding of the function of that system and for the refinement and validation of psychoacoustical and otoacoustic emission methods which are thought to probe the MOC. Based on measurements in anesthetized animals it has been hypothesized that the MOC-reflex (MOCR) can enhance the response to signals in noise, and several lines of evidence support such a role in humans. A difficulty in these studies is the isolation of efferent effects. Efferent activation can be triggered by acoustic stimulation of the contralateral or ipsilateral ear, but ipsilateral stimulation is thought to be more effective. However, ipsilateral stimulation complicates interpretation of effects since these sounds can affect the perception of other ipsilateral sounds by mechanisms not involving olivocochlear efferents. We assessed the ipsilaterally evoked MOCR in human using a transtympanic procedure to record mass-potentials from the cochlear promontory or the niche of the round window. Averaged compound action potential (CAP) responses to masked probe tones of 4 kHz with and without a precursor (designed to activate the MOCR but not the stapedius reflex) were extracted with a polarity alternating paradigm. The masker was either a simultaneous narrow band noise masker or a short (20-ms) tonal ON- or OFF-frequency forward masker. The subjects were screened for normal hearing (audiogram, tympanogram, threshold stapedius reflex) and psychoacoustically tested for the presence of a precursor effect. We observed a clear reduction of CAP amplitude by the precursor, for different masking conditions. Even without an MOCR, this is expected because the precursor will affect the response to subsequent stimuli via neural adaptation. To determine whether the precursor also activated the efferent system, we measured the CAP over a range of masker levels, with or without precursor, and for different types of masker. The results show CAP reduction consistent with the type of gain reduction caused by the MOCR. These results generally support psychoacoustical paradigms designed to probe the efferent system as indeed activating the MOCR system, but not all observations are consistent with this mechanism. PMID:28642679

Contralateral Effects and Binaural Interactions in Dorsal Cochlear Nucleus

PubMed Central

2005-01-01

The dorsal cochlear nucleus (DCN) receives afferent input from the auditory nerve and is thus usually thought of as a monaural nucleus, but it also receives inputs from the contralateral cochlear nucleus as well as descending projections from binaural nuclei. Evidence suggests that some of these commissural and efferent projections are excitatory, whereas others are inhibitory. The goals of this study were to investigate the nature and effects of these inputs in the DCN by measuring DCN principal cell (type IV unit) responses to a variety of contralateral monaural and binaural stimuli. As expected, the results of contralateral stimulation demonstrate a mixture of excitatory and inhibitory influences, although inhibitory effects predominate. Most type IV units are weakly, if at all, inhibited by tones but are strongly inhibited by broadband noise (BBN). The inhibition evoked by BBN is also low threshold and short latency. This inhibition is abolished and excitation is revealed when strychnine, a glycine-receptor antagonist, is applied to the DCN; application of bicuculline, a GABAA-receptor antagonist, has similar effects but does not block the onset of inhibition. Manipulations of discrete fiber bundles suggest that the inhibitory, but not excitatory, inputs to DCN principal cells enter the DCN via its output pathway, and that the short latency inhibition is carried by commissural axons. Consistent with their respective monaural effects, responses to binaural tones as a function of interaural level difference are essentially the same as responses to ipsilateral tones, whereas binaural BBN responses decrease with increasing contralateral level. In comparison to monaural responses, binaural responses to virtual space stimuli show enhanced sensitivity to the elevation of a sound source in ipsilateral space but reduced sensitivity in contralateral space. These results show that the contralateral inputs to the DCN are functionally relevant in natural listening conditions, and that one role of these inputs is to enhance DCN processing of spectral sound localization cues produced by the pinna. PMID:16075189

Benefits of active middle ear implants in mixed hearing loss: Stapes versus round window.

PubMed

Lee, Jeon Mi; Jung, Jinsei; Moon, In Seok; Kim, Sung Huhn; Choi, Jae Young

2017-06-01

We compared the audiologic benefits of active middle ear implants with those of passive middle ear implants with hearing aids in mixed hearing loss, and also compared the outcomes of stapes vibroplasty with those of round window vibroplasty. Retrospective chart review. Thirty-four patients with mixed hearing loss due to chronic otitis media were treated with a middle ear implant. Of these, 15 were treated with a passive middle ear implant (conventional ossiculoplasty with a partial ossicular replacement prosthesis), nine with an active middle ear implant coupling to the stapes, and 10 with an active middle ear implant coupling to the round window. Patients underwent pure-tone/free-field audiograms and speech discrimination tests before surgery and 6 months after surgery, and the results of these tests were compared. The active middle ear implant resulted in better outcomes than the passive middle ear implant with hearing aids at mid to high frequencies (P < .05). Patients who received either a stapes vibroplasty or a round window vibroplasty showed comparable hearing gain except at 8,000 Hz (48.9 dB vs. 31.0 dB, P < .05). Patients who received a stapes vibroplasty showed an improvement even in bone conduction at 1,000 Hz and 2,000 Hz (both P < .05). Active middle ear implantation could be a better option than treatment with passive middle ear implants with hearing aids for achieving rehabilitation in patients with mixed hearing loss. Vibroplasty via either oval window or round window stimulation shares similar good results. 4 Laryngoscope, 127:1435-1441, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Autologous microtia reconstruction combined with ancillary procedures: a comprehensive reconstructive approach.

PubMed

Cugno, S; Farhadieh, R D; Bulstrode, N W

2013-11-01

Autologous microtia reconstruction is generally performed in two stages. The second stage presents a unique opportunity to carry out other complementary procedures. The present study describes our approach to microtia reconstruction, wherein the second stage of reconstruction is combined with final refinements to the ear construct and/or additional procedures to enhance facial contour and symmetry. Retrospective analysis of patients who underwent two-stage microtia reconstruction by a single surgeon (NWB) was conducted in order to ascertain those that had ancillary procedures at the time of the second stage. Patient and operative details were collected. Thirty-four patients (male, 15, median age and age range at second stage, 11 and 10-18 years, respectively) who had complementary procedures executed during the second stage of auricular reconstruction were identified. Collectively, these included centralizing genioplasty (n = 1), fat transfer (n = 22), ear piercing (n = 7), and contralateral prominauris correction (n = 7). Six patients had correction for unilateral isolated microtia and in the remaining 28 patients, auricular reconstruction for microtia associated with a named syndrome. All patients reported a high rate of satisfaction with the result achieved and the majority (85%) reported no perceived need for additional surgical refinements to the ear or procedure(s) to achieve further facial symmetry. No peri- or post-operative complications were noted. Combining the final stage of autologous microtia reconstruction with other ancillary procedures affords a superior aesthetic outcome and decreased patient morbidity. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. All rights reserved.

A defect in early myogenesis causes Otitis media in two mouse models of 22q11.2 Deletion Syndrome

PubMed Central

Fuchs, Jennifer C.; Linden, Jennifer F.; Baldini, Antonio; Tucker, Abigail S.

2015-01-01

Otitis media (OM), the inflammation of the middle ear, is the most common disease and cause for surgery in infants worldwide. Chronic Otitis media with effusion (OME) often leads to conductive hearing loss and is a common feature of a number of craniofacial syndromes, such as 22q11.2 Deletion Syndrome (22q11.2DS). OM is more common in children because the more horizontal position of the Eustachian tube (ET) in infants limits or delays clearance of middle ear effusions. Some mouse models with OM have shown alterations in the morphology and angle of the ET. Here, we present a novel mechanism in which OM is caused not by a defect in the ET itself but in the muscles that control its function. Our results show that in two mouse models of 22q11.2DS (Df1/+ and Tbx1+/−) presenting with bi- or unilateral OME, the fourth pharyngeal arch-derived levator veli palatini muscles were hypoplastic, which was associated with an earlier altered pattern of MyoD expression. Importantly, in mice with unilateral OME, the side with the inflammation was associated with significantly smaller muscles than the contralateral unaffected ear. Functional tests examining ET patency confirmed a reduced clearing ability in the heterozygous mice. Our findings are also of clinical relevance as targeting hypoplastic muscles might present a novel preventative measure for reducing the high rates of OM in 22q11.2DS patients. PMID:25452432

The pathogenesis of cauliflower ear. An experimental study in rabbits.

PubMed

Ohlsén, L; Skoog, T; Sohn, S A

1975-01-01

Appreciating an imcomplete understanding of the pathogenesis of cauliflower ear, an experimental study was designed to demonstrate the pathophysiology of this deformity. The investigation was conducted in 2-month-old rabbits. In one ear a collection of blood was placed under the raised perichondrium which was then sutured back in place and the skin closed. In the other ear an equal amount of blood was deposited between the intact perichondrium and skin. In the first study new cartilage developed under the perichondrium, but in the ear in which the blood was left above the surface of the perichondrium-covered cartilage, complete resorption of the clot occurred. The cauliflower ear was thus shown to be generating cartilage, arising from a layer of raised perichondrium which was further stimulated by a sero-sanguinous medium. The subperichondrial hematoma was extensively invaded by chondroblasts within 2 weeks, and over a period of 4 weeks the new tissue gradually changed into more mature cartilage. It was a consistent finding that the separated perichondrium retracted, thus causing the original cartilage to rise and buckle over the hamatoma, similar to the picture observed in the human pathology.

A prediction of the minke whale (Balaenoptera acutorostrata) middle-ear transfer function.

PubMed

Tubelli, Andrew A; Zosuls, Aleks; Ketten, Darlene R; Yamato, Maya; Mountain, David C

2012-11-01

The lack of baleen whale (Cetacea Mysticeti) audiograms impedes the assessment of the impacts of anthropogenic noise on these animals. Estimates of audiograms, which are difficult to obtain behaviorally or electrophysiologically for baleen whales, can be made by simulating the audiogram as a series of components representing the outer, middle, and inner ear (Rosowski, 1991; Ruggero and Temchin, 2002). The middle-ear portion of the system can be represented by the middle-ear transfer function (METF), a measure of the transmission of acoustic energy from the external ear to the cochlea. An anatomically accurate finite element model of the minke whale (Balaenoptera acutorostrata) middle ear was developed to predict the METF for a mysticete species. The elastic moduli of the auditory ossicles were measured by using nanoindentation. Other mechanical properties were estimated from experimental stiffness measurements or from published values. The METF predicted a best frequency range between approximately 30 Hz and 7.5 kHz or between 100 Hz and 25 kHz depending on stimulation location. Parametric analysis found that the most sensitive parameters are the elastic moduli of the glove finger and joints and the Rayleigh damping stiffness coefficient β. The predicted hearing range matches well with the vocalization range.

Cochlear implantation with hearing preservation yields significant benefit for speech recognition in complex listening environments

PubMed Central

Gifford, René H.; Dorman, Michael F.; Skarzynski, Henryk; Lorens, Artur; Polak, Marek; Driscoll, Colin L. W.; Roland, Peter; Buchman, Craig A.

2012-01-01

Objective The aim of this study was to assess the benefit of having preserved acoustic hearing in the implanted ear for speech recognition in complex listening environments. Design The current study included a within subjects, repeated-measures design including 21 English speaking and 17 Polish speaking cochlear implant recipients with preserved acoustic hearing in the implanted ear. The patients were implanted with electrodes that varied in insertion depth from 10 to 31 mm. Mean preoperative low-frequency thresholds (average of 125, 250 and 500 Hz) in the implanted ear were 39.3 and 23.4 dB HL for the English- and Polish-speaking participants, respectively. In one condition, speech perception was assessed in an 8-loudspeaker environment in which the speech signals were presented from one loudspeaker and restaurant noise was presented from all loudspeakers. In another condition, the signals were presented in a simulation of a reverberant environment with a reverberation time of 0.6 sec. The response measures included speech reception thresholds (SRTs) and percent correct sentence understanding for two test conditions: cochlear implant (CI) plus low-frequency hearing in the contralateral ear (bimodal condition) and CI plus low-frequency hearing in both ears (best aided condition). A subset of 6 English-speaking listeners were also assessed on measures of interaural time difference (ITD) thresholds for a 250-Hz signal. Results Small, but significant, improvements in performance (1.7 – 2.1 dB and 6 – 10 percentage points) were found for the best-aided condition vs. the bimodal condition. Postoperative thresholds in the implanted ear were correlated with the degree of EAS benefit for speech recognition in diffuse noise. There was no reliable relationship among measures of audiometric threshold in the implanted ear nor elevation in threshold following surgery and improvement in speech understanding in reverberation. There was a significant correlation between ITD threshold at 250 Hz and EAS-related benefit for the adaptive SRT. Conclusions Our results suggest that (i) preserved low-frequency hearing improves speech understanding for CI recipients (ii) testing in complex listening environments, in which binaural timing cues differ for signal and noise, may best demonstrate the value of having two ears with low-frequency acoustic hearing and (iii) preservation of binaural timing cues, albeit poorer than observed for individuals with normal hearing, is possible following unilateral cochlear implantation with hearing preservation and is associated with EAS benefit. Our results demonstrate significant communicative benefit for hearing preservation in the implanted ear and provide support for the expansion of cochlear implant criteria to include individuals with low-frequency thresholds in even the normal to near-normal range. PMID:23446225

Middle ear dynamics in response to seismic stimuli in the Cape golden mole (Chrysochloris asiatica).

PubMed

Willi, U B; Bronner, G N; Narins, P M

2006-01-01

The hypertrophied malleus in the middle ear of some golden moles has been assumed to be an adaptation for sensing substrate vibrations by inertial bone conduction, but this has never been conclusively demonstrated. The Cape golden mole (Chrysochloris asiatica) exhibits this anatomical specialization, and the dynamic properties of its middle ear response to vibrations were the subjects of this study. Detailed three-dimensional middle ear anatomy was obtained by x-ray microcomputed tomography (muCT) at a resolution of 12 microm. The ossicular chain exhibits large malleus mass, selective reduction of stiffness and displacement of the center of mass from the suspension points, all favoring low-frequency tuning of the middle ear response. Orientation of the stapes relative to the ossicular chain and the structure of the stapes footplate enable transmission of substrate vibrations arriving from multiple directions to the inner ear. With the long axes of the mallei aligned parallel to the surface, the animal's head was stimulated by a vibration exciter in the vertical and lateral directions over a frequency range from 10 to 600 Hz. The ossicular chain was shown to respond to both vertical and lateral vibrations. Resonant frequencies were found between 71 and 200 Hz and did not differ significantly between the two stimulation directions. Below resonance, the ossicular chain moves in phase with the skull. Near resonance and above, the malleus moves at a significantly larger mean amplitude (5.8+/-2.8 dB) in response to lateral vs vertical stimuli and is 180 degrees out of phase with the skull in both cases. A concise summary of the propagation characteristics of both seismic body (P-waves) and surface (R-waves) is provided. Potential mechanisms by which the animal might exploit the differential response of the ossicular chain to vertical and lateral excitation are discussed in relation to the properties of surface seismic waves.

Transcranial magnetic stimulation of the human brain: responses in muscles supplied by cranial nerves.

PubMed

Benecke, R; Meyer, B U; Schönle, P; Conrad, B

1988-01-01

The present investigation demonstrates that time-varying magnetic fields induced over the skull elicit distinct types of responses in muscles supplied by the cranial nerves both on the ipsilateral and the contralateral side. When the center of the copper coil was positioned 4 cm lateral to the vertex on a line from the vertex to the external auditory meatus, bilateral responses in the masseter, orbicularis oculi, mentalis, and sternocleidomastoideus muscles with a delay of about 10 to 14 ms after the stimulus occurred. Similar to the transcranially evoked muscle responses in hand muscles, the responses in the cranial muscles can be influenced in latency and amplitude by background excitation. It is concluded that these responses are induced by excitation of the face-associated motor cortex followed by multiple I-waves in the corticonuclear tract with both ipsilateral and contralateral projections to the corresponding motoneurones. Additionally, at higher stimulation strengths "short-latency" ipsilateral responses in muscles supplied by the trigeminal, facial, and accessory nerves occurred which we suggest are induced by direct stimulation of the peripheral cranial nerves in their intracisternal course. The present study confirms the bilateral projection of corticonuclear tracts in awake unanesthetised human subjects which has been observed by electrical stimulation on the exposed cortex during surgical procedures already decades ago. The present investigation will serve as a basis for the assessment of pathophysiological mechanisms involving the corticonuclear system or the peripheral cranial nerves in their proximal parts in awake humans.

Development of in vivo gene therapy for hearing disorders: introduction of adeno-associated virus into the cochlea of the guinea pig.

PubMed

Lalwani, A K; Walsh, B J; Reilly, P G; Muzyczka, N; Mhatre, A N

1996-07-01

Gene therapy is currently being used to treat many disorders including cancer, viral infection and the degenerative and fatal diseases of the cardiovascular and the central nervous systems. However, the potential use of gene therapy for alleviation of hearing impairment has not been investigated despite the absence of effective therapy for most forms of inherited hearing disorders. The purpose of this study was to assess the feasibility of introducing genetic material directly into the peripheral auditory system using adeno-associated virus (AAV) as the transfection vector and Hartley guinea pigs as the animal model. Approximately 10(5) particles of AAV containing the bacterial beta-galactosidase (beta-gal) sequence with Ad 2 major late promoter were infused into the cochlea of the animal with the aid of an osmotic minipump. Animals were killed after 2 weeks. Two Hartley guinea pigs with intracochlear saline infusion and four unoperated (nonperfused) animals served as negative controls. Both, the infused and the contralateral, non-infused cochleae were harvested from each animal, decalcified, and embedded in paraffin. Sections, 8 microns in width, were cut from the embedded cochleae and assayed for beta-gal expression via immunohistochemistry. Animals perfused with AAV showed intense immunohistochemical reactivity in the spiral limbus, spiral ligament, spiral ganglion cells and the organ of Corti in the perfused cochlea and a much weaker staining but with similar pattern in the contralateral ear. Cochleae from saline-infused and unoperated animals were devoid of the DAB stain. This study demonstrates for the first time in vivo expression of a foreign gene within the mammalian inner ear resulting from its localized, AAV-mediated introduction. The ability to introduce and stably express exogenous genetic material in the peripheral auditory system will have both experimental and therapeutic benefits. These results lay the groundwork for future studies assessing the potential use of gene therapy for alleviation of hearing impairment.

Experimentally induced otitis and audiogenic seizure in the mouse.

PubMed

Niaussat, M M

1977-04-15

Audiogenic seizures can be induced in genetically non-susceptible 17-day-old mice (Rb/3 strain) with various results. Priming only induces 9% of seizures, auditory insulation 3,8%, while experimental otitis leads to 79%. The hypothesis concerning disuse supersensitivity subsequent to acoustic deprivation was not confirmed by the experiment. However, modification of acoustic transmission at middle ear level induced by otitis or ear physical damage during the maturation period, exposes the upper nervous centers to intense stimulation to which the reaction is a recruiting response.

Plasticity in Human Pitch Perception Induced by Tonotopically Mismatched Electro-Acoustic Stimulation

PubMed Central

Reiss, Lina A.J.; Turner, Christopher W.; Karsten, Sue A.; Gantz, Bruce J.

2013-01-01

Under normal conditions, the acoustic pitch percept of a pure tone is determined mainly by the tonotopic place of the stimulation along the cochlea. Unlike acoustic stimulation, electric stimulation of a cochlear implant (CI) allows for the direct manipulation of the place of stimulation in human subjects. CI sound processors analyze the range of frequencies needed for speech perception and allocate portions of this range to the small number of electrodes distributed in the cochlea. Because the allocation is assigned independently of the original resonant frequency of the basilar membrane associated with the location of each electrode, CI users who have access to residual hearing in either or both ears often have tonotopic mismatches between the acoustic and electric stimulation. Here we demonstrate plasticity of place pitch representations of up to 3 octaves in Hybrid CI users after experience with combined electro-acoustic stimulation. The pitch percept evoked by single CI electrodes, measured relative to acoustic tones presented to the non-implanted ear, changed over time in directions that reduced the electro-acoustic pitch mismatch introduced by the CI programming. This trend was particularly apparent when the allocations of stimulus frequencies to electrodes were changed over time, with pitch changes even reversing direction in some subjects. These findings show that pitch plasticity can occur more rapidly and on a greater scale in the mature auditory system than previously thought possible. Overall, the results suggest that the adult auditory system can impose perceptual order on disordered arrays of inputs. PMID:24157931

Changes in Serial Optical Topography and TMS during Task Performance after Constraint-Induced Movement Therapy in Stroke: A Case Study

PubMed Central

Park, Si-Woon; Butler, Andrew J.; Cavalheiro, Vanessa; Alberts, Jay L.; Wolf, Steven L.

2013-01-01

The authors examined serial changes in optical topography in a stroke patient performing a functional task, as well as clinical and physiologic measures while undergoing constraint-induced therapy (CIT). A 73-year-old right hemiparetic patient, who had a subcortical stroke 4 months previously, received 2 weeks of CIT. During the therapy, daily optical topography imaging using near-infrared light was measured serially while the participant performed a functional key-turning task. Clinical outcome measures included the Wolf Motor Function Test (WMFT), Motor Activity Log (MAL), and functional key grip test. Transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) were also used to map cortical areas and hemodynamic brain responses, respectively. Optical topography measurement showed an overall decrease in oxy-hemoglobin concentration in both hemispheres as therapy progressed and the laterality index increased toward the contralateral hemisphere. An increased TMS motor map area was observed in the contralateral cortex following treatment. Posttreatment fMRI showed bilateral primary motor cortex activation, although slightly greater in the contralateral hemisphere, during affected hand movement. Clinical scores revealed marked improvement in functional activities. In one patient who suffered a stroke, 2 weeks of CIT led to improved function and cortical reorganization in the hemisphere contralateral to the affected hand. PMID:15228805

Low-resolution electromagnetic tomography (LORETA) in children with cochlear implants: a preliminary report.

PubMed

Henkin, Yael; Kishon-Rabin, Liat; Tatin-Schneider, Simona; Urbach, Doron; Hildesheimer, Minka; Kileny, Paul R

2004-12-01

The current preliminary report describes the utilization of low-resolution electromagnetic tomography (LORETA) in a small group of highly performing children using the Nucleus 22 cochlear implant (CI) and in normal-hearing (NH) adults. LORETA current density estimations were performed on an averaged target P3 component that was elicited by non-speech and speech oddball discrimination tasks. The results indicated that, when stimulated with tones, patients with right implants and NH adults (regardless of stimulated ear) showed enhanced activation in the right temporal lobe, whereas patients with left implants showed enhanced activation in the left temporal lobe. When stimulated with speech, patients with right implants showed bilateral activation of the temporal and frontal lobes, whereas patients with left implants showed only left temporal lobe activation. NH adults (regardless of stimulated ear) showed enhanced bilateral activation of the temporal and parietal lobes. The differences in activation patterns between patients with CI and NH subjects may be attributed to the long-term exposure to degraded input conditions which may have resulted in reorganization in terms of functional specialization. The difference between patients with right versus left implants, however, is intriguing and requires further investigation.

Corticospinal activation of internal oblique muscles has a strong ipsilateral component and can be lateralised in man.

PubMed

Strutton, Paul H; Beith, Iain D; Theodorou, Sophie; Catley, Maria; McGregor, Alison H; Davey, Nick J

2004-10-01

Trunk muscles receive corticospinal innervation ipsilaterally and contralaterally and here we investigate the degree of ipsilateral innervation and any cortical asymmetry in pairs of trunk muscles and proximal and distal limb muscles. Transcranial magnetic stimulation (TMS) was applied to left and right motor cortices in turn and bilateral electromyographic (EMG) recordings were made from internal oblique (IO; lower abdominal), deltoid (D; shoulder) and first dorsal interosseus (1DI; hand) muscles during voluntary contraction in ten healthy subjects. We used a 7-cm figure-of-eight stimulating coil located 2 cm lateral and 2 cm anterior to the vertex over either cortex. Incidence of ipsilateral motor evoked potentials (MEPs) was 85% in IO, 40% in D and 35% in 1DI. Mean (+/- S.E.M.) ipsilateral MEP latencies were longer ( P<0.05; paired t-test) than contralateral MEP latencies (contralateral vs. ipsilateral; IO: 16.1+/-0.4 ms vs. 19.0+/-0.5 ms; D: 9.7+/-0.3 ms vs. 15.1+/-1.9 ms; 1DI: 18.3+/-0.6 ms vs. 23.3+/-1.4 ms), suggesting that ipsilateral MEPs were not a result of interhemispheric current spread. Where data were available, we calculated a ratio (ipsilateral MEP areas/contralateral MEP areas) for a given muscle (IO: n=16; D: n=8; 1DI: n=7 ratios). Mean values for these ratios were 0.70+/-0.20 (IO), 0.14+/-0.05 (D) and 0.08+/-0.02 (1DI), revealing stronger ipsilateral drive to IO. Comparisons of the sizes of these ratios revealed a bias towards one cortex or the other (four subjects right; three subjects left). The predominant cortex showed a mean ratio of 1.21+/-0.38 compared with 0.26+/-0.06 in the other cortex ( P<0.05). It appears that the corticospinal control of IO has a strong ipsilateral component relative to the limb muscles and also shows hemispheric asymmetry.

Intracranial electroencephalography power and phase synchronization changes during monaural and binaural beat stimulation.

PubMed

Becher, Ann-Katrin; Höhne, Marlene; Axmacher, Nikolai; Chaieb, Leila; Elger, Christian E; Fell, Juergen

2015-01-01

Auditory stimulation with monaural or binaural auditory beats (i.e. sine waves with nearby frequencies presented either to both ears or to each ear separately) represents a non-invasive approach to influence electrical brain activity. It is still unclear exactly which brain sites are affected by beat stimulation. In particular, an impact of beat stimulation on mediotemporal brain areas could possibly provide new options for memory enhancement or seizure control. Therefore, we examined how electroencephalography (EEG) power and phase synchronization are modulated by auditory stimulation with beat frequencies corresponding to dominant EEG rhythms based on intracranial recordings in presurgical epilepsy patients. Monaural and binaural beat stimuli with beat frequencies of 5, 10, 40 and 80 Hz and non-superposed control signals were administered with low amplitudes (60 dB SPL) and for short durations (5 s). EEG power was intracranially recorded from mediotemporal, temporo-basal and temporo-lateral and surface sites. Evoked and total EEG power and phase synchronization during beat vs. control stimulation were compared by the use of Bonferroni-corrected non-parametric label-permutation tests. We found that power and phase synchronization were significantly modulated by beat stimulation not only at temporo-basal, temporo-lateral and surface sites, but also at mediotemporal sites. Generally, more significant decreases than increases were observed. The most prominent power increases were seen after stimulation with monaural 40-Hz beats. The most pronounced power and synchronization decreases resulted from stimulation with monaural 5-Hz and binaural 80-Hz beats. Our results suggest that beat stimulation offers a non-invasive approach for the modulation of intracranial EEG characteristics. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

The Relationship Between Intensity Coding and Binaural Sensitivity in Adults With Cochlear Implants

PubMed Central

Todd, Ann E.; Goupell, Matthew J.; Litovsky, Ruth Y.

2016-01-01

Objectives Many bilateral cochlear implant users show sensitivity to binaural information when stimulation is provided using a pair of synchronized electrodes. However, there is large variability in binaural sensitivity between and within participants across stimulation sites in the cochlea. It was hypothesized that within-participant variability in binaural sensitivity is in part affected by limitations and characteristics of the auditory periphery which may be reflected by monaural hearing performance. The objective of this study was to examine the relationship between monaural and binaural hearing performance within participants with bilateral cochlear implants. Design Binaural measures included dichotic signal detection and interaural time difference discrimination thresholds. Diotic signal detection thresholds were also measured. Monaural measures included dynamic range and amplitude modulation detection. In addition, loudness growth was compared between ears. Measures were made at three stimulation sites per listener. Results Greater binaural sensitivity was found with larger dynamic ranges. Poorer interaural time difference discrimination was found with larger difference between comfortable levels of the two ears. In addition, poorer diotic signal detection thresholds were found with larger differences between the dynamic ranges of the two ears. No relationship was found between amplitude modulation detection thresholds or symmetry of loudness growth and the binaural measures. Conclusions The results suggest that some of the variability in binaural hearing performance within listeners across stimulation sites can be explained by factors non-specific to binaural processing. The results are consistent with the idea that dynamic range and comfortable levels relate to peripheral neural survival and the width of the excitation pattern which could affect the fidelity with which central binaural nuclei process bilateral inputs. PMID:27787393

Cranial electrotherapy stimulation and transcranial pulsed current stimulation: a computer based high-resolution modeling study.

PubMed

Datta, Abhishek; Dmochowski, Jacek P; Guleyupoglu, Berkan; Bikson, Marom; Fregni, Felipe

2013-01-15

The field of non-invasive brain stimulation has developed significantly over the last two decades. Though two techniques of noninvasive brain stimulation--transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS)--are becoming established tools for research in neuroscience and for some clinical applications, related techniques that also show some promising clinical results have not been developed at the same pace. One of these related techniques is cranial electrotherapy stimulation (CES), a class of transcranial pulsed current stimulation (tPCS). In order to understand further the mechanisms of CES, we aimed to model CES using a magnetic resonance imaging (MRI)-derived finite element head model including cortical and also subcortical structures. Cortical electric field (current density) peak intensities and distributions were analyzed. We evaluated different electrode configurations of CES including in-ear and over-ear montages. Our results confirm that significant amounts of current pass the skull and reach cortical and subcortical structures. In addition, depending on the montage, induced currents at subcortical areas, such as midbrain, pons, thalamus and hypothalamus are of similar magnitude than that of cortical areas. Incremental variations of electrode position on the head surface also influence which cortical regions are modulated. The high-resolution modeling predictions suggest that details of electrode montage influence current flow through superficial and deep structures. Finally we present laptop based methods for tPCS dose design using dominant frequency and spherical models. These modeling predictions and tools are the first step to advance rational and optimized use of tPCS and CES. Copyright © 2012 Elsevier Inc. All rights reserved.

Impedances of the ear estimated with intracochlear pressures in normal human temporal bones

NASA Astrophysics Data System (ADS)

Frear, Darcy; Guan, Xiying; Stieger, Christof; Nakajima, Hideko Heidi

2018-05-01

We have measured intracochlear pressures and velocities of stapes and round window (RW) evoked by air conduction (AC) stimulation in many fresh human cadaveric specimens. Our techniques have improved through the years to ensure reliable pressure sensor measurements in the scala vestibuli and scala tympani. Using these measurements, we have calculated impedances of the middle and inner ear (cochlear partition, RW, and physiological leakage impedance in scala vestibuli) to create a lumped element model. Our model simulates our data and allows us to understand the mechanisms involved in air-conducted sound transmission. In the future this model will be used as a tool to understand transmission mechanisms of various stimuli and to help create more sophisticated models of the ear.

Saccular and utricular inputs to sternocleidomastoid motoneurons of decerebrate cats.

PubMed

Kushiro, K; Zakir, M; Ogawa, Y; Sato, H; Uchino, Y

1999-06-01

Connections from the otolithic organs to sternocleidomastoid (SCM) motoneurons were studied in 20 decerebrate cats. The electrical stimulation was selective for the saccular or the utricular nerves. Postsynaptic potentials were recorded from antidromically identified SCM motoneurons; these muscles participate mainly in neck rotation and flexion. Partial transections of the brainstem at the level of the obex were performed to identify the possible pathway from the otolithic organs to the SCM motoneurons. Saccular or utricular nerve stimulation mainly evoked inhibitory postsynaptic potentials (IPSPs) in the ipsilateral SCM motoneurons. Some of the sacculus-induced IPSPs were preceded by small-amplitude excitatory PSPs (EPSPs). The latencies of the PSPs ranged from 1.8 to 3.1 ms after saccular nerve stimulation and from 1.7 to 2.8 ms after utricular nerve stimulation, indicating that most of the ipsilateral connections were disynaptic. In the contralateral SCM motoneurons, saccular nerve stimulation had no or faint effects, whereas utricular nerve stimulation evoked EPSPs in about two-thirds of neurons, and no visible PSPs in about one-third of neurons. The latencies of the EPSPs ranged from 1.5 to 2.0 ms, indicating the disynaptic connection. Thus, the results suggest a difference between the two otolithic innervating patterns of SCM motoneurons. After transection of the medial vestibulospinal tract (MVST), saccular nerve stimulation did not evoke IPSPs at all in ipsilateral SCM motoneurons, but some (11/40) neurons showed small-amplitude EPSPs. Most (24/33) of the utricular-activated IPSPs disappeared after transection, whereas the other 9 neurons still indicated IPSPs. In the contralateral SCM motoneurons, no utricular-activated EPSPs were recorded after transection. These MVST transection results suggest that most of the otolith-SCM pathways are located in the MVST at the obex level. However, the results also suggest the possibility that other otolith-SCM pathways exist at the obex level.

Computer-assisted three-dimensional reconstructions of ( sup 14 C)-2-deoxy-D-glucose metabolism in cat lumbosacral spinal cord following cutaneous stimulation of the hindfoot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crockett, D.P.; Smith, W.K.; Proshansky, E.

1989-10-08

We report on computer-assisted three-dimensional reconstruction of spinal cord activity associated with stimulation of the plantar cushion (PC) as revealed by (14C)-2-deoxy-D-glucose (2-DG) serial autoradiographs. Moderate PC stimulation in cats elicits a reflex phasic plantar flexion of the toes. Four cats were chronically spinalized at about T6 under barbiturate anesthesia. Four to 11 days later, the cats were injected (i.v.) with 2-DG (100 microCi/kg) and the PC was electrically stimulated with needle electrodes at 2-5 times threshold for eliciting a reflex. Following stimulation, the spinal cord was processed for autoradiography. Subsequently, autoradiographs, representing approximately 8-18 mm from spinal segments L6-S1,more » were digitized for computer analysis and 3-D reconstruction. Several strategies of analysis were employed: (1) Three-dimensional volume images were color-coded to represent different levels of functional activity. (2) On the reconstructed volumes, virtual sections were made in the horizontal, sagittal, and transverse planes to view regions of 2-DG activity. (3) In addition, we were able to sample different regions within the grey and white matter semi-quantitatively (i.e., pixel intensity) from section to section to reveal differences between ipsi- and contralateral activity, as well as possible variation between sections. These analyses revealed 2-DG activity associated with moderate PC stimulation, not only in the ipsilateral dorsal horn as we had previously demonstrated, but also in both the ipsilateral and contralateral ventral horns, as well as in the intermediate grey matter. The use of novel computer analysis techniques--combined with an unanesthetized preparation--enabled us to demonstrate that the increased metabolic activity in the lumbosacral spinal cord associated with PC stimulation was much more extensive than had heretofore been observed.« less

Cochlear Implants (For Parents)

MedlinePlus

... nerve, and send it to the brain. The cochlear implant package is made up of: a receiver-stimulator that contains all of the electronic circuits that control the flow of electrical pulses into the ear an antenna ...

oVEMP as an objective indicator of successful repositioning maneuver.

PubMed

Asal, Samir; Sobhy, Osama; Balbaa, Amany

Benign paroxysmal positioning vertigo (BPPV) is the most common peripheral vestibular disorder. Canalolithiasis in the posterior semi-circular canal is the most common underlying pathology that can be treated effectively by repositioning maneuvers. Our hypothesis suggested that successful maneuvers can lead to repositioning of dislodged otoconia to the utricle. Air conducted oVEMP, which is thought to originate from the contra-lateral utricular organ was measured in twenty patients with unilateral BPPV and we compared n1-p1 peak to peak amplitude of the affected ears in 3 separate intervals: on pre-treatment when typical nystagmus was confirmed, immediately after, and 1 week after repositioning maneuvers to assess change, if any, in amplitude. This study showed significant increase of oVEMP amplitude in the affected ears after successful repositioning maneuver that was more significant after 1 week. oVEMP can be used as a reliable objective test for ensuring a successful maneuver rather than subjective dependence on the patient's symptoms, which may be misleading due to a remission. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Reducing Xerostomia After Chemo-IMRT for Head and Neck Cancer: Beyond Sparing the Parotid Glands

PubMed Central

Little, Michael; Schipper, Matthew; Feng, Felix Y.; Vineberg, Karen; Cornwall, Craig; Murdoch-Kinch, Carol-Anne; Eisbruch, Avraham

2011-01-01

Purpose To assess whether in addition to sparing parotid glands (PGs), xerostomia after chemo-IMRT of head and neck cancer is affected by reducing doses to other salivary glands. Methods Prospective study: 78 patients with stages III/IV oropharynx/nasopharynx cancers received chemo-IMRT aiming to spare the parts outside the targets of bilateral PGs, oral cavity (OC) containing the minor salivary glands, and contralateral submandibular gland (SMG) (when contralateral level I was not a target). Pretherapy and periodically through 24 months, validated patient-reported xerostomia questionnaires (XQ) scores and observer-graded xerostomia were recorded, and stimulated and unstimulated saliva measured selectively from each of the PGs and SMGs. Mean OC doses served as surrogates of minor salivary glands dysfunction. Regression models assessed XQ and observer-graded xerostomia predictors. Results Statistically significant predictors of the XQ score in univariate analysis included OC, PG, and SMG mean doses, as well as baseline XQ score, time since RT, and both stimulated and unstimulated PG saliva flow rates. Similar factors were statistically significant predictors of observer-graded xerostomia. OC, PG and SMG mean doses were moderately inter-correlated (r=0.47–0.55). In multivariate analyses, after adjusting for PG and SMG doses, OC mean dose (p < 0.0001), time from RT (p < 0.0001), and stimulated PG saliva (p < 0.0025) were significant predictors for XQ scores, and OC mean dose and time for observer-graded xerostomia. While scatter plots showed no thresholds, OC mean doses <40 Gy and contralateral SMG mean <50 Gy were each associated with low patient-reported and observer-rated xerostomia at almost all post-therapy time points. Conclusion PG, SMG and OC mean doses were significant predictors of both patient-reported and observer-rated xerostomia after chemo-IMRT, with OC doses remaining significant after adjusting for PG and SMG doses. These results support efforts to spare all salivary glands by IMRT, beyond the PGs alone. PMID:22056067

Sustained Spatial Attention to Vibrotactile Stimulation in the Flutter Range: Relevant Brain Regions and Their Interaction

PubMed Central

Goltz, Dominique; Pleger, Burkhard; Thiel, Sabrina; Villringer, Arno; Müller, Matthias M.

2013-01-01

The present functional magnetic resonance imaging (fMRI) study was designed to get a better understanding of the brain regions involved in sustained spatial attention to tactile events and to ascertain to what extent their activation was correlated. We presented continuous 20 Hz vibrotactile stimuli (range of flutter) concurrently to the left and right index fingers of healthy human volunteers. An arrow cue instructed subjects in a trial-by-trial fashion to attend to the left or right index finger and to detect rare target events that were embedded in the vibrotactile stimulation streams. We found blood oxygen level-dependent (BOLD) attentional modulation in primary somatosensory cortex (SI), mainly covering Brodmann area 1, 2, and 3b, as well as in secondary somatosensory cortex (SII), contralateral to the to-be-attended hand. Furthermore, attention to the right (dominant) hand resulted in additional BOLD modulation in left posterior insula. All of the effects were caused by an increased activation when attention was paid to the contralateral hand, except for the effects in left SI and insula. In left SI, the effect was related to a mixture of both a slight increase in activation when attention was paid to the contralateral hand as well as a slight decrease in activation when attention was paid to the ipsilateral hand (i.e., the tactile distraction condition). In contrast, the effect in left posterior insula was exclusively driven by a relative decrease in activation in the tactile distraction condition, which points to an active inhibition when tactile information is irrelevant. Finally, correlation analyses indicate a linear relationship between attention effects in intrahemispheric somatosensory cortices, since attentional modulation in SI and SII were interrelated within one hemisphere but not across hemispheres. All in all, our results provide a basis for future research on sustained attention to continuous vibrotactile stimulation in the range of flutter. PMID:24367642

The Dynamics of the Stapedial Acoustic Reflex.

NASA Astrophysics Data System (ADS)

Moss, Sherrin Mary

Available from UMI in association with The British Library. This thesis aims to separate the neural and muscular components of the stapedial acoustic reflex, both anatomically and physiologically. It aims to present an hypothesis to account for the differences between ipsilateral and contralateral reflex characteristics which have so far been unexplained, and achieve a greater understanding of the mechanisms underlying the reflex dynamics. A technique enabling faithful reproduction of the time course of the reflex is used throughout the experimental work. The technique measures tympanic membrane displacement as a result of reflex stapedius muscle contraction. The recorded response can be directly related to the mechanics of the middle ear and stapedius muscle contraction. Some development of the technique is undertaken by the author. A model of the reflex neural arc and stapedius muscle dynamics is evolved that is based upon a second order system. The model is unique in that it includes a latency in the ipsilateral negative feedback loop. Oscillations commonly observed on reflex responses are seen to be produced because of the inclusion of a latency in the feedback loop. The model demonstrates and explains the complex relationships between neural and muscle dynamic parameters observed in the experimental work. This more comprehensive understanding of the interaction between the stapedius dynamics and the neural arc of the reflex would not usually have been possible using human subjects, coupled with a non-invasive measurement technique. Evidence from the experimental work revealed the ipsilateral reflex to have, on average, a 5 dB lower threshold than the contralateral reflex. The oscillatory charcteristics, and the steady state response, of the contralateral reflex are also seen to be significantly different from those of the ipsilateral reflex. An hypothesis to account for the experimental observations is proposed. It is propounded that chemical neurotransmitters, and their effect upon the contralateral reflex arc from the site of the superior olivary complex to the motoneurones innervating the stapedius, account for the difference between the contralateral and ipsilateral reflex thresholds and dynamic characteristics. In the past two years the measurement technique used for the experimental work has developed from an audiological to a neurological diagnostic tool. This has enabled the results from the study to be applied in the field for valuable biomechanical and neurological explanations of the reflex response. (Abstract shortened by UMI.).

History of Resuscitation :4. Development of Resuscitation in the Mid-18 Century-4 : External Stimulation to the Body.

PubMed

Asai, Takashi

2017-05-01

From the mid-18th century, several different stimulations were used to attempt to resuscitate apparently dead people. These include sound, smell, and light stimulation to the ear, nose and eyes, rubbing the body surface and spirit given to the oral cavity. The most notable stimulation was use of electricity, which was initiated by better understanding of its power by Benjamin Franklin and Luigi A. Galvani. Charles Kite developed the first electrical machine to stimulate the heart, and by 1800, it was found that the most effective site for applying electricity was over the heart.

Innate immune recognition of molds and homology to the inner ear protein, cochlin, in patients with autoimmune inner ear disease

PubMed Central

Pathak, Shresh; Hatam, Lynda J.; Bonagura, Vincent; Vambutas, Andrea

2013-01-01

Autoimmune Inner Ear Disease (AIED) is characterized by bilateral, fluctuating sensorineural hearing loss with periods of hearing decline triggered by unknown stimuli. Here we examined whether an environmental exposure to mold in these AIED patients is sufficient to generate a pro-inflammatory response that may, in part, explain periods of acute exacerbation of disease. We hypothesized that molds may stimulate an aberrant immune response in these patients as both several Aspergillus species and penecillium share homology with the LCCL domain of the inner ear protein, cochlin. We showed the presence of higher levels of anti-mold IgG in plasma of AIED patients at dilution of 1:256 (p=0.032) and anti-cochlin IgG 1:256 (p=0.0094 and at 1:512 p=0.024) as compared with controls. Exposure of peripheral blood mononuclear cells (PBMC) of AIED patients to mold resulted in an up-regulation of IL-1β mRNA expression, enhanced IL-1β and IL-6 secretion, and generation of IL-17 expressing cells in mold-sensitive AIED patients, suggesting mold acts as a PAMP in a subset of these patients. Naïve B cells secreted IgM when stimulated with conditioned supernatant from AIED patients’ monocytes treated with mold extract. In conclusion, the present studies indicate that fungal exposure can trigger autoimmunity in a subset of susceptible AIED patients. PMID:23912888

Human middle-ear nonlinearity measurements using laser Doppler vibrometry

NASA Astrophysics Data System (ADS)

Gladiné, Kilian; Muyshondt, Pieter G. G.; Dirckx, Joris J. J.

2017-12-01

It has long been supposed that the middle-ear has near to perfect linear characteristics, and several attempts have been made to investigate this hypothesis. In conclusion, the middle-ear was regarded as a linear system at least up till sound pressure levels of 120 dB. Because of the linear relationship between Doppler shift of light and the vibration velocity of the object on which the light is reflected, laser Doppler vibrometry (LDV) is an intrinsically highly linear measurement technique. Therefore it allows straightforward detection of very small nonlinearities in a vibration response. In this paper, laser Doppler vibrometry and multisine stimulation are used to detect nonlinear distortions in the vibration response at the umbo of the tympanic membrane of seven human cadaver temporal bones. Nonlinear distortions were detected starting from sound pressure levels of 99 dB and measurements were performed up to 120 dB. These distortions can be subdivided into even degree (e.g. quadratic distortion tones) and odd degree nonlinear distortions (e.g. cubic distortion tones). We illustrate that with odd multisine stimulation the level of even and odd degree nonlinear distortions can be investigated separately. In conclusion, laser Doppler vibrometry is an adequate tool to detect nonlinear distortions in the middle-ear system and to quantify the level of such distortions even at 57 dB below the vibration response. The possibility to analyze even degree and odd degree nonlinear distortion levels separately can help in future work to pinpoint the source of the nonlinearity.

Acute repair of traumatic pan-brachial plexus injury: technical considerations and approaches.

PubMed

Abou-Al-Shaar, Hussam; Karsy, Michael; Ravindra, Vijay; Joyce, Evan; Mahan, Mark A

2018-01-01

Particularly challenging after complete brachial plexus avulsion is reestablishing effective hand function, due to limited neurological donors to reanimate the arm. Acute repair of avulsion injuries may enable reinnervation strategies for achieving hand function. This patient presented with pan-brachial plexus injury. Given its irreparable nature, the authors recommended multistage reconstruction, including contralateral C-7 transfer for hand function, multiple intercostal nerves for shoulder/triceps function, shoulder fusion, and spinal accessory nerve-to-musculocutaneous nerve transfer for elbow flexion. The video demonstrates distal contraction from electrical stimulation of the avulsed roots. Single neurorrhaphy of the contralateral C-7 transfer was performed along with a retrosternocleidomastoid approach. The video can be found here: https://youtu.be/GMPfno8sK0U .

Intracortical circuits, sensorimotor integration and plasticity in human motor cortical projections to muscles of the lower face

PubMed Central

Pilurzi, G; Hasan, A; Saifee, T A; Tolu, E; Rothwell, J C; Deriu, F

2013-01-01

Previous studies of the cortical control of human facial muscles documented the distribution of corticobulbar projections and the presence of intracortical inhibitory and facilitatory mechanisms. Yet surprisingly, given the importance and precision in control of facial expression, there have been no studies of the afferent modulation of corticobulbar excitability or of the plasticity of synaptic connections in the facial primary motor cortex (face M1). In 25 healthy volunteers, we used standard single- and paired-pulse transcranial magnetic stimulation (TMS) methods to probe motor-evoked potentials (MEPs), short-intracortical inhibition, intracortical facilitation, short-afferent and long-afferent inhibition and paired associative stimulation in relaxed and active depressor anguli oris muscles. Single-pulse TMS evoked bilateral MEPs at rest and during activity that were larger in contralateral muscles, confirming that corticobulbar projection to lower facial muscles is bilateral and asymmetric, with contralateral predominance. Both short-intracortical inhibition and intracortical facilitation were present bilaterally in resting and active conditions. Electrical stimulation of the facial nerve paired with a TMS pulse 5–200 ms later showed no short-afferent inhibition, but long-afferent inhibition was present. Paired associative stimulation tested with an electrical stimulation–TMS interval of 20 ms significantly facilitated MEPs for up to 30 min. The long-term potentiation, evoked for the first time in face M1, demonstrates that excitability of the facial motor cortex is prone to plastic changes after paired associative stimulation. Evaluation of intracortical circuits in both relaxed and active lower facial muscles as well as of plasticity in the facial motor cortex may provide further physiological insight into pathologies affecting the facial motor system. PMID:23297305

Magnetically driven middle ear ossicles for optical measurement of vibrations in an ear with opened tympanic membrane

NASA Astrophysics Data System (ADS)

Peacock, J.; von Unge, M.; Dirckx, J.

2013-12-01

Vibrations of the middle ear ossicles are easily measured by means of laser vibrometry. However, laser vibrometry requires free visual access to the object under investigation, and acquiring free visual access to the ossicles through the ear canal requires the removal of the tympanic membrane (TM), with the result that the ossicles can no longer be stimulated acoustically. To overcome this, we devised a new setup in which the ossicles can be driven magnetically. After measuring the response of the TM to an acoustic signal, we then remove it and attach a small magnet to the exposed manubrium (a part of the most lateral auditory ossicle, the malleus, which is normally attached to the TM). An electromagnetic excitation coil is then used to drive the magnet, and the output to the coil adjusted until the vibration of the manubrium, as measured by the vibrometer, matches that measured in response to the acoustic signal. Such a setup may have uses in research on middle ear mechanics, such as the measurement of nonlinearities in their response, as well as applications in the diagnosis of middle ear conditions such as the fixation of the ossicles by otosclerosis or in chronic otitis media. We describe our setup and discuss the viability of our method and its future clinical potential by presenting some measurements on an artificially fixated ear.

Gerbil middle-ear sound transmission from 100 Hz to 60 kHz1

PubMed Central

Ravicz, Michael E.; Cooper, Nigel P.; Rosowski, John J.

2008-01-01

Middle-ear sound transmission was evaluated as the middle-ear transfer admittance HMY (the ratio of stapes velocity to ear-canal sound pressure near the umbo) in gerbils during closed-field sound stimulation at frequencies from 0.1 to 60 kHz, a range that spans the gerbil’s audiometric range. Similar measurements were performed in two laboratories. The HMY magnitude (a) increased with frequency below 1 kHz, (b) remained approximately constant with frequency from 5 to 35 kHz, and (c) decreased substantially from 35 to 50 kHz. The HMY phase increased linearly with frequency from 5 to 35 kHz, consistent with a 20–29 μs delay, and flattened at higher frequencies. Measurements from different directions showed that stapes motion is predominantly pistonlike except in a narrow frequency band around 10 kHz. Cochlear input impedance was estimated from HMY and previously-measured cochlear sound pressure. Results do not support the idea that the middle ear is a lossless matched transmission line. Results support the ideas that (1) middle-ear transmission is consistent with a mechanical transmission line or multiresonant network between 5 and 35 kHz and decreases at higher frequencies, (2) stapes motion is pistonlike over most of the gerbil auditory range, and (3) middle-ear transmission properties are a determinant of the audiogram. PMID:18646983

Magnetoencephalographic study of hand and foot sensorimotor organization in 325 consecutive patients evaluated for tumor or epilepsy surgery

PubMed Central

Willemse, Ronald B.; Hillebrand, Arjan; Ronner, Hanneke E.; Peter Vandertop, W.; Stam, Cornelis J.

2015-01-01

Objectives The presence of intracranial lesions or epilepsy may lead to functional reorganization and hemispheric lateralization. We applied a clinical magnetoencephalography (MEG) protocol for the localization of the contralateral and ipsilateral S1 and M1 of the foot and hand in patients with non-lesional epilepsy, stroke, developmental brain injury, traumatic brain injury and brain tumors. We investigated whether differences in activation patterns could be related to underlying pathology. Methods Using dipole fitting, we localized the sources underlying sensory and motor evoked magnetic fields (SEFs and MEFs) of both hands and feet following unilateral stimulation of the median nerve (MN) and posterior tibial nerve (PTN) in 325 consecutive patients. The primary motor cortex was localized using beamforming following a self-paced repetitive motor task for each hand and foot. Results The success rate for motor and sensory localization for the feet was significantly lower than for the hands (motor_hand 94.6% versus motor_feet 81.8%, p < 0.001; sensory_hand 95.3% versus sensory_feet 76.0%, p < 0.001). MN and PTN stimulation activated 86.6% in the contralateral S1, with ipsilateral activation < 0.5%. Motor cortex activation localized contralaterally in 76.1% (5.2% ipsilateral, 7.6% bilateral and 11.1% failures) of all motor MEG recordings. The ipsilateral motor responses were found in 43 (14%) out of 308 patients with motor recordings (range: 8.3–50%, depending on the underlying pathology), and had a higher occurrence in the foot than in the hand (motor_foot 44.8% versus motor_hand 29.6%, p = 0.031). Ipsilateral motor responses tended to be more frequent in patients with a history of stroke, traumatic brain injury (TBI) or developmental brain lesions (p = 0.063). Conclusions MEG localization of sensorimotor cortex activation was more successful for the hand compared to the foot. In patients with neural lesions, there were signs of brain reorganization as measured by more frequent ipsilateral motor cortical activation of the foot in addition to the traditional sensory and motor activation patterns in the contralateral hemisphere. The presence of ipsilateral neural reorganization, especially around the foot motor area, suggests that careful mapping of the hand and foot in both contralateral and ipsilateral hemispheres prior to surgery might minimize postoperative deficits. PMID:26693401

Recognition and localization of speech by adult cochlear implant recipients wearing a digital hearing aid in the nonimplanted ear (bimodal hearing).

PubMed

Potts, Lisa G; Skinner, Margaret W; Litovsky, Ruth A; Strube, Michael J; Kuk, Francis

2009-06-01

The use of bilateral amplification is now common clinical practice for hearing aid users but not for cochlear implant recipients. In the past, most cochlear implant recipients were implanted in one ear and wore only a monaural cochlear implant processor. There has been recent interest in benefits arising from bilateral stimulation that may be present for cochlear implant recipients. One option for bilateral stimulation is the use of a cochlear implant in one ear and a hearing aid in the opposite nonimplanted ear (bimodal hearing). This study evaluated the effect of wearing a cochlear implant in one ear and a digital hearing aid in the opposite ear on speech recognition and localization. A repeated-measures correlational study was completed. Nineteen adult Cochlear Nucleus 24 implant recipients participated in the study. The participants were fit with a Widex Senso Vita 38 hearing aid to achieve maximum audibility and comfort within their dynamic range. Soundfield thresholds, loudness growth, speech recognition, localization, and subjective questionnaires were obtained six-eight weeks after the hearing aid fitting. Testing was completed in three conditions: hearing aid only, cochlear implant only, and cochlear implant and hearing aid (bimodal). All tests were repeated four weeks after the first test session. Repeated-measures analysis of variance was used to analyze the data. Significant effects were further examined using pairwise comparison of means or in the case of continuous moderators, regression analyses. The speech-recognition and localization tasks were unique, in that a speech stimulus presented from a variety of roaming azimuths (140 degree loudspeaker array) was used. Performance in the bimodal condition was significantly better for speech recognition and localization compared to the cochlear implant-only and hearing aid-only conditions. Performance was also different between these conditions when the location (i.e., side of the loudspeaker array that presented the word) was analyzed. In the bimodal condition, the speech-recognition and localization tasks were equal regardless of which side of the loudspeaker array presented the word, while performance was significantly poorer for the monaural conditions (hearing aid only and cochlear implant only) when the words were presented on the side with no stimulation. Binaural loudness summation of 1-3 dB was seen in soundfield thresholds and loudness growth in the bimodal condition. Measures of the audibility of sound with the hearing aid, including unaided thresholds, soundfield thresholds, and the Speech Intelligibility Index, were significant moderators of speech recognition and localization. Based on the questionnaire responses, participants showed a strong preference for bimodal stimulation. These findings suggest that a well-fit digital hearing aid worn in conjunction with a cochlear implant is beneficial to speech recognition and localization. The dynamic test procedures used in this study illustrate the importance of bilateral hearing for locating, identifying, and switching attention between multiple speakers. It is recommended that unilateral cochlear implant recipients, with measurable unaided hearing thresholds, be fit with a hearing aid.

Initial Stage Reference Search : Behavioral Economics and Transportation

DOT National Transportation Integrated Search

2015-04-01

The initial stage investigation is the beginning step in the Exploratory Advanced Research (EAR) Program process for exploring ideas across traditional and nontraditional fields of research and stimulating new approaches to problem solving. The proce...

Exploratory Advanced Research Program

DOT National Transportation Integrated Search

2013-08-20

The Exploratory Advanced Research Program strives to develop partnerships with the public and private sectors because the very nature of EAR is to apply ideas across traditional fields of research and stimulate new approaches to problem solving. Thro...

Three-dimensional autologous cartilage framework fabrication assisted by new additive manufactured ear-shaped templates for microtia reconstruction.

PubMed

Zhou, Jiayu; Pan, Bo; Yang, Qinghua; Zhao, Yanyong; He, Leren; Lin, Lin; Sun, Hengyun; Song, Yupeng; Yu, Xiaobo; Sun, Zhongyang; Jiang, Haiyue

2016-10-01

During microtia reconstruction, the intraoperative design of the cartilage framework is important for the appearance and symmetry of the bilateral auricles. Templates (traditionally, the X-ray film template) are usually utilized to complete the task, which can provide cues regarding size, cranioauricular angle and positioning to the surgeons. With a combination of three-dimensional (3D) scanning and additive manufacturing (AM) techniques, we utilized two different ear-shaped templates (sheet moulding and 3D templates) during the fabrication of 3D-customized autologous cartilage frameworks for auricle reconstruction. Forty unilateral microtia patients were included in the study. All the patients underwent auricle reconstruction using the tissue-expanding technique assisted by the new AM templates. Images were processed using computer-aided design software and exported to print two different AM ear-shaped templates: sheet moulding and 3D. Both templates were assisted by the 3D framework fabrication. The 3D images of each patient's head were captured preoperatively using a 3D scanner. X-ray film templates were also made for the patients. The lengths and widths of the contralateral auricles, X-ray film and sheet moulding templates were measured in triplicate. The error of the template and the contralateral auricle were used to compare the accuracy between the two templates. Between January and May 2014, 40 unilateral microtia patients aged 6-29 years were included in this study. All patients underwent auricle reconstruction using autogenous costal cartilage. The sterilized AM templates were used to assist in the framework fabrication. The operative time was decreased by an average of 15 min compared with the method assisted by the X-ray film template. Postoperative appearance evaluation (based on five indexes: symmetry, length, width, cranioauricular angle and the substructure of the reconstructed ear) was performed by both the doctors and the patients (or their parents). Follow-up (ranging from 9 to 18 months) showed that all of the patients obtained satisfactory results with life-like 3D configuration and symmetric cranioauricular angle. The follow-up showed that no surgery-related complications occurred. Comparing the accuracy of the X-ray film and sheet moulding templates, the average errors of length were 1.8 mm ± 1.44 mm and 0.39 mm ± 0.35 mm, respectively, and the average width errors were 1.32 mm ± 0.88 mm and 0.3 mm ± 0.47 mm, respectively. The new sheet moulding template was more accurate than the X-ray template. The new sheet-moulding template is much more accurate than the traditional X-ray film template. Framework fabrication assisted by accurate 3D and informative AM templates contributed to individualized cartilage framework fabrication and satisfactory results. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

MICROLESIONS OF THE INFERIOR OLIVE REDUCE VESTIBULAR MODULATION OF PURKINJE CELL COMPLEX AND SIMPLE SPIKES IN MOUSE CEREBELLUM

PubMed Central

Barmack, N.H.; Yakhnitsa, V.

2011-01-01

Cerebellar Purkinje cells have two distinct action potentials: Complex spikes (CSs) are evoked by single climbing fibers that originate from the contralateral inferior olive. Simple spikes (SSs) are often ascribed to mossy fiber---granule cell---parallel fiber inputs to Purkinje cells. Although generally accepted, this view lacks experimental support. Vestibular stimulation independently activates primary afferent mossy fibers and tertiary afferent climbing fibers that project to theuvula-nodulus (folia 8-10). CSs and SSs normally discharge antiphasically during sinusoidal roll-tilt. When CSs increase, SSs decrease. We tested the relative independence of these pathways in mice by making electrolytic microlesions of the two inferior olivary nuclei from which vestibular climbing fibers originate; the β-nucleus and dorsomedial cell column (DMCC). This reduced vestibular climbing fiber signaling to the contralateral folia 8-10, while leaving intact vestibular primary and secondary afferent mossy fibers. We recorded from Purkinje cells and interneurons in folia 8-10, identified by juxtacellular labeling with neurobiotin. Microlesions of the inferior olive increased the spontaneous discharge of SSs in contralateral folia 8-10, but blocked their modulation during vestibular stimulation. The vestibularly-evoked discharge of excitatory cerebellar interneurons (granule cells and unipolar brush cells) was not modified by olivary microlesions. The modulated discharge of stellate cells, but not Golgi cells was reduced by olivary microlesions. We conclude that vestibular modulation of CSs and SSs depends on intact climbing fibers. The absence of vestibularly-modulated SSs following olivary microlesions reflects the loss of climbing fiber-evoked stellate cell discharge. PMID:21734274

Broadened population-level frequency tuning in the auditory cortex of tinnitus patients.

PubMed

Sekiya, Kenichi; Takahashi, Mariko; Murakami, Shingo; Kakigi, Ryusuke; Okamoto, Hidehiko

2017-03-01

Tinnitus is a phantom auditory perception without an external sound source and is one of the most common public health concerns that impair the quality of life of many individuals. However, its neural mechanisms remain unclear. We herein examined population-level frequency tuning in the auditory cortex of unilateral tinnitus patients with similar hearing levels in both ears using magnetoencephalography. We compared auditory-evoked neural activities elicited by a stimulation to the tinnitus and nontinnitus ears. Objective magnetoencephalographic data suggested that population-level frequency tuning corresponding to the tinnitus ear was significantly broader than that corresponding to the nontinnitus ear in the human auditory cortex. The results obtained support the hypothesis that pathological alterations in inhibitory neural networks play an important role in the perception of subjective tinnitus. NEW & NOTEWORTHY Although subjective tinnitus is one of the most common public health concerns that impair the quality of life of many individuals, no standard treatment or objective diagnostic method currently exists. We herein revealed that population-level frequency tuning was significantly broader in the tinnitus ear than in the nontinnitus ear. The results of the present study provide an insight into the development of an objective diagnostic method for subjective tinnitus. Copyright © 2017 the American Physiological Society.

A prediction of the minke whale (Balaenoptera acutorostrata) middle-ear transfer functiona)

PubMed Central

Tubelli, Andrew A.; Zosuls, Aleks; Ketten, Darlene R.; Yamato, Maya; Mountain, David C.

2012-01-01

The lack of baleen whale (Cetacea Mysticeti) audiograms impedes the assessment of the impacts of anthropogenic noise on these animals. Estimates of audiograms, which are difficult to obtain behaviorally or electrophysiologically for baleen whales, can be made by simulating the audiogram as a series of components representing the outer, middle, and inner ear (Rosowski, 1991; Ruggero and Temchin, 2002). The middle-ear portion of the system can be represented by the middle-ear transfer function (METF), a measure of the transmission of acoustic energy from the external ear to the cochlea. An anatomically accurate finite element model of the minke whale (Balaenoptera acutorostrata) middle ear was developed to predict the METF for a mysticete species. The elastic moduli of the auditory ossicles were measured by using nanoindentation. Other mechanical properties were estimated from experimental stiffness measurements or from published values. The METF predicted a best frequency range between approximately 30 Hz and 7.5 kHz or between 100 Hz and 25 kHz depending on stimulation location. Parametric analysis found that the most sensitive parameters are the elastic moduli of the glove finger and joints and the Rayleigh damping stiffness coefficient β. The predicted hearing range matches well with the vocalization range. PMID:23145610

Effects of electrical stimulation of the lateral aspect of the prefrontal cortex upon attack behavior in cats.

PubMed

Siegel, A; Edinger, H; Dotto, M

1975-08-15

An experiment was performed to determine the role of the lateral aspect of the prefrontal cortex upon quiet biting attack behavior elicited from the hypothalamus in the cat. The results of this experiment indicate that stimulation of 19 of 28 electrode sites sampled in the lateral prefrontal cortex produced a statistically significant inhibition of attack behavior elicited from the hypothalamus of the ipsilateral side. Stimulation of sites in the prefrontal cortex on the side contralateral to the hypothalamus from which attack was elicited had no effect upon this response. No systematic effect of prefrontal stimulation upon flight behavior was observed. Anatomical studies suggest that the lateral prefrontal cortex may inhibit attack behavior by modulating neurons in either the mediodorsal thalamic nucleus or ventral tegmental area.

Ipsilateral masking between acoustic and electric stimulations.

PubMed

Lin, Payton; Turner, Christopher W; Gantz, Bruce J; Djalilian, Hamid R; Zeng, Fan-Gang

2011-08-01

Residual acoustic hearing can be preserved in the same ear following cochlear implantation with minimally traumatic surgical techniques and short-electrode arrays. The combined electric-acoustic stimulation significantly improves cochlear implant performance, particularly speech recognition in noise. The present study measures simultaneous masking by electric pulses on acoustic pure tones, or vice versa, to investigate electric-acoustic interactions and their underlying psychophysical mechanisms. Six subjects, with acoustic hearing preserved at low frequencies in their implanted ear, participated in the study. One subject had a fully inserted 24 mm Nucleus Freedom array and five subjects had Iowa/Nucleus hybrid implants that were only 10 mm in length. Electric masking data of the long-electrode subject showed that stimulation from the most apical electrodes produced threshold elevations over 10 dB for 500, 625, and 750 Hz probe tones, but no elevation for 125 and 250 Hz tones. On the contrary, electric stimulation did not produce any electric masking in the short-electrode subjects. In the acoustic masking experiment, 125-750 Hz pure tones were used to acoustically mask electric stimulation. The acoustic masking results showed that, independent of pure tone frequency, both long- and short-electrode subjects showed threshold elevations at apical and basal electrodes. The present results can be interpreted in terms of underlying physiological mechanisms related to either place-dependent peripheral masking or place-independent central masking.

Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator.

PubMed

Luo, Chuan; Omelchenko, Irina; Manson, Robert; Robbins, Carol; Oesterle, Elizabeth C; Cao, Guo Zhong; Shen, I Y; Hume, Clifford R

2015-12-01

Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800 µm by 800 µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24 kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays. © The Author(s) 2015.

Parallel pathways from motor and somatosensory cortex for controlling whisker movements in mice

PubMed Central

Sreenivasan, Varun; Karmakar, Kajari; Rijli, Filippo M; Petersen, Carl C H

2015-01-01

Mice can gather tactile sensory information by actively moving their whiskers to palpate objects in their immediate surroundings. Whisker sensory perception therefore requires integration of sensory and motor information, which occurs prominently in the neocortex. The signalling pathways from the neocortex for controlling whisker movements are currently poorly understood in mice. Here, we delineate two pathways, one originating from primary whisker somatosensory cortex (wS1) and the other from whisker motor cortex (wM1), that control qualitatively distinct movements of contralateral whiskers. Optogenetic stimulation of wS1 drove retraction of contralateral whiskers while stimulation of wM1 drove rhythmic whisker protraction. To map brainstem pathways connecting these cortical areas to whisker motor neurons, we used a combination of anterograde tracing using adenoassociated virus injected into neocortex and retrograde tracing using monosynaptic rabies virus injected into whisker muscles. Our data are consistent with wS1 driving whisker retraction by exciting glutamatergic premotor neurons in the rostral spinal trigeminal interpolaris nucleus, which in turn activate the motor neurons innervating the extrinsic retractor muscle nasolabialis. The rhythmic whisker protraction evoked by wM1 stimulation might be driven by excitation of excitatory and inhibitory premotor neurons in the brainstem reticular formation innervating both intrinsic and extrinsic muscles. Our data therefore begin to unravel the neuronal circuits linking the neocortex to whisker motor neurons. PMID:25476605

Altered impulse activity modifies synaptic physiology and mitochondria in crayfish phasic motor neurons.

PubMed

Nguyen, P V; Atwood, H L

1994-12-01

1. Crayfish phasic motor synapses produce large initial excitatory postsynaptic potentials (EPSPs) that fatigue rapidly during high-frequency stimulation. Periodic in vivo stimulation of an identified phasic abdominal extensor motor neuron (axon 3) induced long-term adaptation (LTA) of neuromuscular transmission: initial EPSP amplitude became smaller and synaptic depression was significantly reduced. We tested the hypothesis that activity-induced synaptic fatigue-resistance seen during LTA was dependent upon, or correlated with, mitochondrial oxidative competence. 2. Periodic unilateral conditioning stimulation of axon 3 entering each of two adjacent homologous abdominal segments (segments 2 and 3) increased the synaptic stamina in both "conditioned" axons; mean final EPSP amplitudes, recorded after 20 min of 5-Hz test stimulation, were significantly larger than those measured with the same protocol from contralateral unstimulated axons. 3. During 5-Hz test stimulation of the conditioned axon 3 of segment 3, acute superfusion with 0.8 mM dinitrophenol or 20 mM sodium azide [inhibitors of oxidative adenosinetriphosphate (ATP) synthesis] produced increased synaptic depression. Drug-free saline superfusion of the conditioned axon 3 of segment 2 in these same animals did not affect the increased synaptic fatigue resistance seen in this segment. Thus both successful induction (in axon 3 of saline-perfused segment 2) and attenuation (in axon 3 of drug-perfused segment 3) of the increased synaptic stamina can be demonstrated with this twin-segment conditioning protocol. 4. Confocal microscopic imaging of mitochondrial rhodamine-123 (Rh123) fluorescence was used to assess relative oxidative competence of conditioned and unconditioned phasic axons. Conditioned phasic axons showed significantly higher mean mitochondrial Rh123 fluorescence than contralateral unstimulated axons. In the same preparations that showed increased postconditioning Rh123 fluorescence, the synaptic fatigue resistance measured from conditioned axon 3 was also significantly greater than that recorded from contralateral unstimulated axon 3. 5. Axotomy of the phasic extensor nerve root (containing axon 3), before in vivo conditioning stimulation of its decentralized segment, prevented induction of both the increased synaptic stamina in axon 3 and the enhanced mitochondrial fluorescence in decentralized motor axons of the nerve root. Hence, induction of both changes requires axonal transport of materials between the soma and the motor synapses of axon 3. 5. Axotomy of the phasic extensor nerve root (containing axon 3), before in vivo conditioning stimulation of its decentralized segment, Prevented induction of both the increased synaptic stamina in axon 3 and the enhanced mitochondrial fluorescence in decentralized motor axons of the nerve root Hence, induction of both changes requires axonal transport of materials between the soma and the motor synapses of axon 3 6. Because mitochondrial Rh123 fluorescence is primarily dependent upon the oxidative activity of these organelles, our findings suggest that conditioning stimulation of phasic extensor axon 3 increases its mitochondrial oxidative competence and that the enhanced synaptic stamina seen during LTA in axon 3 is correlated with, and dependent upon, oxidative activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Acoustic Immittance, Absorbance, and Reflectance in the Human Ear Canal

PubMed Central

Rosowski, John J.; Wilber, Laura Ann

2015-01-01

Ear canal measurements of acoustic immittance (a term that groups impedance and its inverse, admittance) and the related quantities of acoustic reflectance and power absorbance have been used to assess auditory function and aid in the differential diagnosis of conductive hearing loss for over 50 years. The change in such quantities after stimulation of the acoustic reflex also has been used in diagnosis. In this article, we define these quantities, describe how they are commonly measured, and discuss appropriate calibration procedures and standards necessary for accurate immittance/reflectance measurements. PMID:27516708

Central vs. peripheral neuraxial sympathetic control of porcine ventricular electrophysiology

PubMed Central

Yamakawa, Kentaro; Howard-Quijano, Kimberly; Zhou, Wei; Rajendran, Pradeep; Yagishita, Daigo; Vaseghi, Marmar; Ajijola, Olujimi A.; Armour, J. Andrew; Shivkumar, Kalyanam; Ardell, Jeffrey L.

2015-01-01

Sympathoexcitation is associated with ventricular arrhythmogenesis. The aim of this study was to determine the role of thoracic dorsal root afferent neural inputs to the spinal cord in modulating ventricular sympathetic control of normal heart electrophysiology. We hypothesize that dorsal root afferent input tonically modulates basal and evoked efferent sympathetic control of the heart. A 56-electrode sock placed on the epicardial ventricle in anesthetized Yorkshire pigs (n = 17) recorded electrophysiological function, as well as activation recovery interval (ARI) and dispersion in ARI, at baseline conditions and during stellate ganglion electrical stimulation. Measures were compared between intact states and sequential unilateral T1–T4 dorsal root transection (DRTx), ipsilateral ventral root transection (VRTx), and contralateral dorsal and ventral root transections (DVRTx). Left or right DRTx decreased global basal ARI [Lt.DRTx: 369 ± 12 to 319 ± 13 ms (P < 0.01) and Rt.DRTx: 388 ± 19 to 356 ± 15 ms (P < 0.01)]. Subsequent unilateral VRTx followed by contralateral DRx+VRTx induced no further change. In intact states, left and right stellate ganglion stimulation shortened ARIs (6 ± 2% vs. 17 ± 3%), while increasing dispersion (+139% vs. +88%). There was no difference in magnitude of ARI or dispersion change with stellate stimulation following spinal root transections. Interruption of thoracic spinal afferent signaling results in enhanced basal cardiac sympathoexcitability without diminishing the sympathetic response to stellate ganglion stimulation. This suggests spinal dorsal root transection releases spinal cord-mediated tonic inhibitory control of efferent sympathetic tone, while maintaining intrathoracic cardiocentric neural networks. PMID:26661096

Impairment of sensory-motor plasticity in mild Alzheimer's disease.

PubMed

Terranova, Carmen; Carmen, Terranova; SantAngelo, Antonino; Antonino, Sant'Angelo; Morgante, Francesca; Francesca, Morgante; Rizzo, Vincenzo; Vincenzo, Rizzo; Allegra, Roberta; Roberta, Allegra; Arena, Maria Grazia; Grazia, Arena Maria; Ricciardi, Lucia; Lucia, Ricciardi; Ghilardi, Marie Felice; Felice, Ghilardi Maria; Girlanda, Paolo; Paolo, Girlanda; Quartarone, Angelo; Angelo, Quartarone

2013-01-01

Primary motor cortex (M1) is relatively spared in the early stages of Alzheimer's disease (AD). Aim of the present study was to investigate whether abnormal M1 synaptic plasticity is present at an early stage of AD. We employed an electrophysiological protocol, named rapid paired associative stimulation (rPAS), involving repetitive transcranial magnetic stimulation (rTMS) paired with electrical stimulation of the contralateral median nerve, that modifies corticospinal excitability and short latency afferent inhibition (SAI). We studied 10 patients with a diagnosis of probable mild AD according to the Mini Mental State Examination score (minimum 21) and 14 age-matched control subjects. Motor evoked potentials (MEP) amplitudes and short-afferent inhibition (SAI) were measured at baseline before and for up to 60 min after 5Hz-rPAS in abductor pollicis brevis (APB). rPAS consisted of 600 pairs of transcranial magnetic stimuli, at a rate of 5 Hz for 2 min, coupled with electrical median nerve stimulation preceding TMS over the contralateral M1 at an inter-stimulus interval of 25 ms. Baseline SAI was significantly reduced in AD patients. In the control subjects rPAS induced a significant increase in MEP amplitudes and a decrease of SAI in the APB muscle persistently for up to 1 h. Conversely 5Hz-rPAS did not induce any significant changes in MEP amplitudes and SAI in mild AD patients. Sensory-motor plasticity is impaired in the motor cortex of AD at an early stage of the disease. Copyright © 2013 Elsevier Inc. All rights reserved.

Pattern of Corticospinal Projections Defined by Brain Mapping During Resective Epilepsy Surgery in a Patient with Congenital Hemiparesis and Intractable Epilepsy.

PubMed

Yang, Chen-Ya; Chen, Hsin-Hung; Chen, Chien; Chiu, Jan-Wei; Chou, Chen-Liang; Yang, Tsui-Fen

2017-11-01

Congenital or early-onset brain structural lesions often cause contralateral hemiparesis, cognitive deficits, developmental delays, and seizures. Seizure is the most debilitating condition, as it greatly impairs quality of life in both the affected individuals and their caregivers and prevents them from active social participation. A 34-year-old man with hemiparesis and early-onset seizures since childhood owing to a congenital brain lesion developed intractable seizures in the last 2 years and was subsequently admitted for resective epileptic surgery. During the operation, we employed an innovative intraoperative neurophysiologic monitoring technique. In contrast to routine application for transcranial stimulation, we recorded compound muscle action potentials over the bilateral limb muscles simultaneously, instead of over the contralateral muscles only, to determine the patterns of the corticospinal projections. Transcranial stimulation over the bilateral hemispheres was applied before craniotomy, and direct cortical stimulation over the lesioned hemisphere was applied after craniotomy. By integrating both approaches, we could first identify the pattern of corticospinal projections before craniotomy and then accurately define the noneloquent area, which guided the resection to successfully accomplish the surgical goal. This technique is simple because no patient participation is required. We believe that it has the potential to replace conventional preoperative functional magnetic resonance imaging and transcranial magnetic stimulation in resective epilepsy surgery, particularly for young patients. Not only can it improve the safety of surgical procedures, but also it can help predict functional outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

The Electrically Evoked Auditory Change Complex Evoked by Temporal Gaps Using Cochlear Implants or Auditory Brainstem Implants in Children With Cochlear Nerve Deficiency.

PubMed

He, Shuman; McFayden, Tyler C; Shahsavarani, Bahar S; Teagle, Holly F B; Ewend, Matthew; Henderson, Lillian; Buchman, Craig A

This study aimed to (1) establish the feasibility of measuring the electrically evoked auditory change complex (eACC) in response to temporal gaps in children with cochlear nerve deficiency (CND) who are using cochlear implants (CIs) and/or auditory brainstem implants (ABIs); and (2) explore the association between neural encoding of, and perceptual sensitivity to, temporal gaps in these patients. Study participants included 5 children (S1 to S5) ranging in age from 3.8 to 8.2 years (mean: 6.3 years) at the time of testing. All subjects were unilaterally implanted with a Nucleus 24M ABI due to CND. For each subject, two or more stimulating electrodes of the ABI were tested. S2, S3, and S5 previously received a CI in the contralateral ear. For these 3 subjects, at least two stimulating electrodes of their CIs were also tested. For electrophysiological measures, the stimulus was an 800-msec biphasic pulse train delivered to individual electrodes at the maximum comfortable level (C level). The electrically evoked responses, including the onset response and the eACC, were measured for two stimulation conditions. In the standard condition, the 800-msec pulse train was delivered uninterrupted to individual stimulating electrodes. In the gapped condition, a temporal gap was inserted into the pulse train after 400 msec of stimulation. Gap durations tested in this study ranged from 2 up to 128 msec. The shortest gap that could reliably evoke the eACC was defined as the objective gap detection threshold (GDT). For behavioral GDT measures, the stimulus was a 500-msec biphasic pulse train presented at the C level. The behavioral GDT was measured for individual stimulating electrodes using a one-interval, two-alternative forced-choice procedure. The eACCs to temporal gaps were recorded successfully in all subjects for at least one stimulating electrode using either the ABI or the CI. Objective GDTs showed intersubject variations, as well as variations across stimulating electrodes of the ABI or the CI within each subject. Behavioral GDTs were measured for one ABI electrode in S2 and for multiple ABI and CI electrodes in S5. All other subjects could not complete the task. S5 showed smaller behavioral GDTs for CI electrodes than those measured for ABI electrodes. One CI and two ABI electrodes in S5 showed comparable objective and behavioral GDTs. In contrast, one CI and two ABI electrodes in S5 and one ABI electrode in S2 showed measurable behavioral GDTs but no identifiable eACCs. The eACCs to temporal gaps were recorded in children with CND using either ABIs or CIs. Both objective and behavioral GDTs showed inter- and intrasubject variations. Consistency between results of eACC recordings and psychophysical measures of GDT was observed for some but not all ABI or CI electrodes in these subjects.

Airway compromise secondary to vagus nerve stimulator: case report and implications for otolaryngologists.

PubMed

Bhatt, Y M; Hans, P S; Belloso, A

2010-05-01

Vagus nerve stimulators are devices used in the management of patients with drug-refractory epilepsy unsuitable for resective or disconnective surgery. Implanted usually by neurosurgeons, these devices are infrequently encountered by otolaryngologists. Despite significant anti-seizure efficacy, side effects related to laryngopharyngeal stimulation are not uncommon. A 28-year-old man with a history of effective vagus nerve stimulator use presented with a cluster of seizures and respiratory distress associated with intermittent stridor. The duration of stridor corresponded to the period of vagus nerve stimulation. Endoscopy revealed forced adduction of the left vocal fold against a medialised right vocal fold. The device was switched off and the stridor immediately resolved. Airway compromise is an under-recognised side effect of vagus nerve stimulation. We describe the first known case of stridor and contralateral vocal fold palsy in a vagus nerve stimulator user. We highlight the need for better understanding amongst otolaryngologists of the laryngopharyngeal side effects of this technology.

Association of microRNA 146 with middle ear hyperplasia in pediatric otitis media.

PubMed

Samuels, Tina L; Yan, Justin; Khampang, Pawjai; MacKinnon, Alexander; Hong, Wenzhou; Johnston, Nikki; Kerschner, Joseph E

2016-09-01

Toll-like receptor signaling activated by bacterial otitis media pathogens in the middle ear has been shown to play a key role in OM susceptibility, pathogenesis and recovery. Recent studies implicate microRNA 146 (miR-146) in regulation of inflammation via negative feedback of toll-like receptor signaling (TLR) in a wide variety of tissues, however its involvement in otitis media is unknown. Human middle ear epithelial cells were stimulated with proinflammatory cytokines, interleukin 1 beta or tumor necrosis factor alpha, for two to twenty-four hours. Middle ear biopsies were collected from children with otitis media with effusion (n = 20), recurrent otitis media (n = 9), and control subjects undergoing cochlear implantation (n = 10). miR-146a, miR-146b expression was assayed by quantitative PCR (qPCR). Expression of miR-146 targets involved in TLR signaling, IRAK1 and TRAF6, was assayed by qPCR in middle ear biopsies. Middle ear biopsies were cryosectioned and epithelial thickness measured by a certified pathologist. Proinflammatory cytokines induced expression of miR-146 in middle ear epithelial cells in vitro. Middle ear miR-146a and miR-146b expression was elevated in otitis media patients relative to control subjects and correlated with middle ear epithelial thickness. A trend towards inverse correlation was observed between miR-146 and TRAF6 expression in the clinical population. This report is the first to assess miRNA expression in a clinical population with OM. Findings herein suggest miR-146 may play a role in OM. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Factors constraining the benefit to speech understanding of combining information from low-frequency hearing and a cochlear implant.

PubMed

Dorman, Michael F; Cook, Sarah; Spahr, Anthony; Zhang, Ting; Loiselle, Louise; Schramm, David; Whittingham, JoAnne; Gifford, Rene

2015-04-01

Many studies have documented the benefits to speech understanding when cochlear implant (CI) patients can access low-frequency acoustic information from the ear opposite the implant. In this study we assessed the role of three factors in determining the magnitude of bimodal benefit - (i) the level of CI-only performance, (ii) the magnitude of the hearing loss in the ear with low-frequency acoustic hearing and (iii) the type of test material. The patients had low-frequency PTAs (average of 125, 250 and 500 Hz) varying over a large range (<30 dB HL to >70 dB HL) in the ear contralateral to the implant. The patients were tested with (i) CNC words presented in quiet (n = 105) (ii) AzBio sentences presented in quiet (n = 102), (iii) AzBio sentences in noise at +10 dB signal-to-noise ratio (SNR) (n = 69), and (iv) AzBio sentences at +5 dB SNR (n = 64). We find maximum bimodal benefit when (i) CI scores are less than 60 percent correct, (ii) hearing loss is less than 60 dB HL in low-frequencies and (iii) the test material is sentences presented against a noise background. When these criteria are met, some bimodal patients can gain 40-60 percentage points in performance relative to performance with a CI. This article is part of a Special Issue entitled . Copyright © 2014 Elsevier B.V. All rights reserved.

[Effects of stimulation of dorso-medial area of nucleus facialis on respiration related units in ventro-lateral region of nucleus tractus solitaris in rabbits].

PubMed

Gao, J X; Liu, L

1990-10-01

In urethane-anesthetized, vagotomized and paralyzed rabbits, effects of electrical stimulation of the dorso-medial area of the nucleus facialis (DMNF) on the respiration-related units (RRUs) in ventro-lateral region of nucleus tractus solitaris (VLNTS) were observed. The experimental results showed that during electrical stimulation of DMNF the majority of the inspiratory (I) neurons (64.4%) were increased in frequency and duration of discharge, some to a marked extent. During electrical stimulation of DMNF the expiratory neurons (35%) were decreased in their frequency and duration of discharge, some to a marked extent too. The responses of RRUs in ipsilateral and contralateral VLNTS to stimulation of DMNF was not statistically significant (P greater than 0.05). It is suggested that DMNF may have a facilitating effect on the inspiratory neurons and an inhibiting effect on the expiratory neurons in VLNTS.

Cathodal transcranial direct current stimulation in children with dystonia: a pilot open-label trial.

PubMed

Young, Scott J; Bertucco, Matteo; Sheehan-Stross, Rebecca; Sanger, Terence D

2013-10-01

Studies suggest that dystonia is associated with increased motor cortex excitability. Cathodal transcranial direct current stimulation can temporarily reduce motor cortex excitability. To test whether stimulation of the motor cortex can reduce dystonic symptoms in children, we measured tracking performance and muscle overflow using an electromyogram tracking task before and after stimulation. Of 10 participants, 3 showed a significant reduction in overflow, and a fourth showed a significant reduction in tracking error. Overflow decreased more when the hand contralateral to the cathode performed the task than when the hand ipsilateral to the cathode performed the task. Averaged over all participants, the results did not reach statistical significance. These results suggest that cathodal stimulation may allow a subset of children to control muscles or reduce involuntary overflow activity. Further testing is needed to confirm these results in a blinded trial and identify the subset of children who are likely to respond.

Increased regional cerebral blood flow in the contralateral thalamus after successful motor cortex stimulation in a patient with poststroke pain.

PubMed

Saitoh, Youichi; Osaki, Yasuhiro; Nishimura, Hiroshi; Hirano, Shun-ichiro; Kato, Amami; Hashikawa, Kazuo; Hatazawa, Jun; Yoshimine, Toshiki

2004-05-01

The mechanisms underlying poststroke pain have not been clearly identified. Although motor cortex stimulation (MCS) sometimes reduces poststroke pain successfully, the exact mechanism is not yet known. For further investigation of the neural pathways involved in the processing of poststroke pain and in pain reduction by MCS, the authors used positron emission tomography (PET) scanning to determine significant changes in regional cerebral blood flow (rCBF). This 58-year-old right-handed man suffered from right-sided poststroke pain for which he underwent implantation of a stimulation electrode in the right motor cortex. After 30 minutes of stimulation, his pain was remarkably reduced (Visual Analog Scale scores decreased 8 to 1) and he felt warmth in his left arm. The rCBF was studied using PET scanning with 15O-labeled water when the patient was in the following states: before MCS (painful condition, no stimulation) and after successful MCS (painless condition, no stimulation). The images were analyzed using statistical parametric mapping software. State-dependent differences in global blood flow were covaried using analysis of covariance. Comparisons of the patient's rCBF in the painful condition with that in the painless condition revealed significant rCBF increases in the left rectus gyrus (BA11), left superior frontal lobe (BA9), left anterior cingulate gyms (BA32), and the left thalamus (p < 0.05, corrected). On the other hand, there were significant decreases in rCBF in the right superior temporal gyrus (BA22, p < 0.01, corrected) and the left middle occipital gyrus (BA19, p < 0.05, corrected). The efficacy of MCS was mainly related to increased synaptic activity in the thalamus, whereas the activations in the rectus gyrus, anterior cingulate gyrus, and superior frontal cortex as well as the inactivation of the superior temporal lobe may be related to emotional processes. This is the first report in which the contralateral thalamus was significantly activated and pain relief was achieved using MCS.

The technique for 3D printing patient-specific models for auricular reconstruction.

PubMed

Flores, Roberto L; Liss, Hannah; Raffaelli, Samuel; Humayun, Aiza; Khouri, Kimberly S; Coelho, Paulo G; Witek, Lukasz

2017-06-01

Currently, surgeons approach autogenous microtia repair by creating a two-dimensional (2D) tracing of the unaffected ear to approximate a three-dimensional (3D) construct, a difficult process. To address these shortcomings, this study introduces the fabrication of patient-specific, sterilizable 3D printed auricular model for autogenous auricular reconstruction. A high-resolution 3D digital photograph was captured of the patient's unaffected ear and surrounding anatomic structures. The photographs were exported and uploaded into Amira, for transformation into a digital (.stl) model, which was imported into Blender, an open source software platform for digital modification of data. The unaffected auricle as digitally isolated and inverted to render a model for the contralateral side. The depths of the scapha, triangular fossa, and cymba were deepened to accentuate their contours. Extra relief was added to the helical root to further distinguish this structure. The ear was then digitally deconstructed and separated into its individual auricular components for reconstruction. The completed ear and its individual components were 3D printed using polylactic acid filament and sterilized following manufacturer specifications. The sterilized models were brought to the operating room to be utilized by the surgeon. The models allowed for more accurate anatomic measurements compared to 2D tracings, which reduced the degree of estimation required by surgeons. Approximately 20 g of the PLA filament were utilized for the construction of these models, yielding a total material cost of approximately $1. Using the methodology detailed in this report, as well as departmentally available resources (3D digital photography and 3D printing), a sterilizable, patient-specific, and inexpensive 3D auricular model was fabricated to be used intraoperatively. This technique of printing customized-to-patient models for surgeons to use as 'guides' shows great promise. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Benefits of Localization and Speech Perception with Multiple Noise Sources in Listeners with a Short-electrode Cochlear Implant

PubMed Central

Dunn, Camille C.; Perreau, Ann; Gantz, Bruce; Tyler, Richard

2009-01-01

Background Research suggests that for individuals with significant low-frequency hearing, implantation of a short-electrode cochlear implant may provide benefits of improved speech perception abilities. Because this strategy combines acoustic and electrical hearing within the same ear while at the same time preserving low-frequency residual acoustic hearing in both ears, localization abilities may also be improved. However, very little research has focused on the localization and spatial hearing abilities of users with a short-electrode cochlear implant. Purpose The purpose of this study was to evaluate localization abilities for listeners with a short-electrode cochlear implant who continue to wear hearing aids in both ears. A secondary purpose was to document speech perception abilities using a speech in noise test with spatially-separate noise sources. Research Design Eleven subjects that utilized a short-electrode cochlear implant and bilateral hearing aids were tested on localization and speech perception with multiple noise locations using an eight-loudspeaker array. Performance was assessed across four listening conditions using various combinations of cochlear implant and/or hearing aid use. Results Results for localization showed no significant difference between using bilateral hearing aids and bilateral hearing aids plus the cochlear implant. However, there was a significant difference between the bilateral hearing aid condition and the implant plus use of a contralateral hearing aid for all eleven subjects. Results for speech perception showed a significant benefit when using bilateral hearing aids plus the cochlear implant over use of the implant plus only one hearing aid. Conclusion Combined use of both hearing aids and the cochlear implant show significant benefits for both localization and speech perception in noise for users with a short-electrode cochlear implant. These results emphasize the importance of low-frequency information in two ears for the purpose of localization and speech perception in noise. PMID:20085199

Benefits of localization and speech perception with multiple noise sources in listeners with a short-electrode cochlear implant.

PubMed

Dunn, Camille C; Perreau, Ann; Gantz, Bruce; Tyler, Richard S

2010-01-01

Research suggests that for individuals with significant low-frequency hearing, implantation of a short-electrode cochlear implant may provide benefits of improved speech perception abilities. Because this strategy combines acoustic and electrical hearing within the same ear while at the same time preserving low-frequency residual acoustic hearing in both ears, localization abilities may also be improved. However, very little research has focused on the localization and spatial hearing abilities of users with a short-electrode cochlear implant. The purpose of this study was to evaluate localization abilities for listeners with a short-electrode cochlear implant who continue to wear hearing aids in both ears. A secondary purpose was to document speech perception abilities using a speech-in-noise test with spatially separate noise sources. Eleven subjects that utilized a short-electrode cochlear implant and bilateral hearing aids were tested on localization and speech perception with multiple noise locations using an eight-loudspeaker array. Performance was assessed across four listening conditions using various combinations of cochlear implant and/or hearing aid use. Results for localization showed no significant difference between using bilateral hearing aids and bilateral hearing aids plus the cochlear implant. However, there was a significant difference between the bilateral hearing aid condition and the implant plus use of a contralateral hearing aid for all 11 subjects. Results for speech perception showed a significant benefit when using bilateral hearing aids plus the cochlear implant over use of the implant plus only one hearing aid. Combined use of both hearing aids and the cochlear implant show significant benefits for both localization and speech perception in noise for users with a short-electrode cochlear implant. These results emphasize the importance of low-frequency information in two ears for the purpose of localization and speech perception in noise.

Cochlear Implant Electrode Effect on Sound Energy Transfer within the Cochlea during Acoustic Stimulation

PubMed Central

Greene, Nathaniel T.; Mattingly, Jameson K.; Jenkins, Herman A.; Tollin, Daniel J.; Easter, James R.; Cass, Stephen P.

2015-01-01

Hypothesis Cochlear implants (CI) designed for hearing preservation will not alter mechanical properties of the middle and inner ear as measured by intracochlear pressure (PIC) and stapes velocity (Vstap). Background CIs designed to provide combined electrical and acoustic stimulation (EAS) are now available. To maintain functional acoustic hearing, it is important to know if a CI electrode can alter middle or inner ear mechanics, as any alteration could contribute to elevated low-frequency thresholds in EAS patients. Methods Seven human cadaveric temporal bones were prepared, and pure-tone stimuli from 120Hz–10kHz were presented at a range of intensities up to 110 dB SPL. PIC in the scala vestibuli (PSV) and tympani (PST) were measured with fiber-optic pressure sensors concurrently with VStap using laser Doppler vibrometry. Five CI electrodes from two different manufacturers, with varying dimensions were inserted via a round window approach at six different depths (16–25 mm). Results The responses of PIC and VStap to acoustic stimulation were assessed as a function of stimulus frequency, normalized to SPL in the external auditory canal (EAC), in baseline and electrode inserted conditions. Responses measured with electrodes inserted were generally within ~5 dB of baseline, indicating little effect of cochlear implant electrode insertion on PIC and VStap. Overall, mean differences across conditions were small for all responses, and no substantial differences were consistently visible across electrode types. Conclusions Results suggest that the influence of a CI electrode on middle and inner ear mechanics is minimal, despite variation in electrode lengths and configurations. PMID:26333018

Why noise-induced hearing loss of industrial workers is dramatic while that of similarly assessed musicians has been described as trivial

NASA Astrophysics Data System (ADS)

Bies, David

2005-09-01

Criteria for noise exposure considered acceptable for hearing protection are based upon industrial experience, yet these same criteria do not describe the experience of musicians. Investigation of the physics of the human ear reveals a basic design compromise that explains this anomaly. Acoustic stimulation is encoded in the velocity response of the basilar membrane, which makes possible the use of damping control to achieve the dynamic range of the ear. The use of damping control for this purpose without unacceptable distortions is possible if damping is slowly varying. The ear is free running and guided by previous instruction, making it vulnerable to loud impulsive sounds. To protect the ear the aural reflex is provided, but this protection is limited to frequencies below about 1 to 2 kHz. In the natural environment this design compromise is satisfactory, but in the industrial environment loud impulsive sounds are common and the compromise fails. It is to be noted that impulsive sounds of high frequency and level for which the ear has no defense, and which are not characteristic of music, are averaged to zero using standard assessment procedures.

CCL11 elicits secretion of RNases from mouse eosinophils and their cell-free granules

PubMed Central

Shamri, Revital; Melo, Rossana C. N.; Young, Kristen M.; Bivas-Benita, Maytal; Xenakis, Jason J.; Spencer, Lisa A.; Weller, Peter F.

2012-01-01

Rapid secretion of eosinophil-associated RNases (EARs), such as the human eosinophilic cationic protein (ECP), from intracellular granules is central to the role of eosinophils in allergic diseases and host immunity. Our knowledge regarding allergic inflammation has advanced based on mouse experimental models. However, unlike human eosinophils, capacities of mouse eosinophils to secrete granule proteins have been controversial. To study mechanisms of mouse eosinophil secretion and EAR release, we combined an RNase assay of mouse EARs with ultrastructural studies. In vitro, mouse eosinophils stimulated with the chemokine eotaxin-1 (CCL11) secreted enzymatically active EARs (EC50 5 nM) by piecemeal degranulation. In vivo, in a mouse model of allergic airway inflammation, increased airway eosinophil infiltration (24-fold) correlated with secretion of active RNases (3-fold). Moreover, we found that eosinophilic inflammation in mice can involve eosinophil cytolysis and release of cell-free granules. Cell-free mouse eosinophil granules expressed functional CCR3 receptors and secreted their granule proteins, including EAR and eosinophil peroxidase in response to CCL11. Collectively, these data demonstrate chemokine-dependent secretion of EARs from both intact mouse eosinophils and their cell-free granules, findings pertinent to understanding the pathogenesis of eosinophil-associated diseases, in which EARs are key factors.—Shamri, R., Melo, R. C. N., Young, K. M., B.-B, M., Xenakis, J. J., Spencer, L. A., Weller, P. F. CCL11 elicits secretion of RNases from mouse eosinophils and their cell-free granules. PMID:22294786

Identification of specific gene expression profiles in fibroblasts derived from middle ear cholesteatoma.

PubMed

Yoshikawa, Mamoru; Kojima, Hiromi; Wada, Kota; Tsukidate, Toshiharu; Okada, Naoko; Saito, Hirohisa; Moriyama, Hiroshi

2006-07-01

To investigate the role of fibroblasts in the pathogenesis of cholesteatoma. Tissue specimens were obtained from our patients. Middle ear cholesteatoma-derived fibroblasts (MECFs) and postauricular skin-derived fibroblasts (SFs) as controls were then cultured for a few weeks. These fibroblasts were stimulated with interleukin (IL) 1alpha and/or IL-1beta before gene expression assays. We used the human genome U133A probe array (GeneChip) and real-time polymerase chain reaction to examine and compare the gene expression profiles of the MECFs and SFs. Six patients who had undergone tympanoplasty. The IL-1alpha-regulated genes were classified into 4 distinct clusters on the basis of profiles differentially regulated by SF and MECF using a hierarchical clustering analysis. The messenger RNA expressions of LARC (liver and activation-regulated chemokine), GMCSF (granulocyte-macrophage colony-stimulating factor), epiregulin, ICAM1 (intercellular adhesion molecule 1), and TGFA (transforming growth factor alpha) were more strongly up-regulated by IL-1alpha and/or IL-1beta in MECF than in SF, suggesting that these fibroblasts derived from different tissues retained their typical gene expression profiles. Fibroblasts may play a role in hyperkeratosis of middle ear cholesteatoma by releasing molecules involved in inflammation and epidermal growth. These fibroblasts may retain tissue-specific characteristics presumably controlled by epigenetic mechanisms.

Circuits that Innervate Excitatory-Inhibitory Cells in the Inferior Colliculus Obtained with In-Vivo Whole Cell Recordings

PubMed Central

Li, Na; Pollak, George D.

2013-01-01

Neurons excited by stimulation of one ear and suppressed by the other, called EI neurons, are sensitive to interaural intensity disparities (IIDs), the cues animals use to localize high frequencies. EI neurons are first formed in lateral superior olive (LSO), which then sends excitatory projections to the dorsal nucleus of the lateral lemniscus (DNLL) and the inferior colliculus (IC), both of which contain large populations of EI cells. We evaluate the inputs that innervate EI cells in the IC of Mexican free-tailed bats, Tadarida brasilensis mexicana, with in vivo whole cell recordings from which we derived excitatory and inhibitory conductances. We show that the basic EI property in the majority of IC cells is inherited from LSO, but each type of EI cell is also innervated by the ipsi- or contralateral DNLL, as well as additional excitatory and inhibitory inputs from monaural nuclei. We identify three EI types, where each type receives a set of projections that are different from the other types. To evaluate the role that the various projections played in generating binaural responses, we used modeling to compute a predicted response from the conductances. We then omitted one of the conductances from the computation to evaluate the degree to which that input contributed to the binaural response. We show that formation of the EI property in the various types is complex, and that some projections exert such subtle influences that they could not have been detected with extracellular recordings or even from intracellular recordings of post-synaptic potentials. PMID:23575835

Access to aidable residual hearing in adult candidates for cochlear implantation in the UK.

PubMed

Fielden, Claire A; Hampton, Rosa; Smith, Sandra; Kitterick, Pádraig T

2016-04-01

Guidance from the National Institute for Health and Care Excellence (NICE) permits candidates to receive a cochlear implant provided they only hear sounds louder than 90 dB HL at 2 and 4 kHz. In some patients, their level of residual hearing may be sufficient to warrant the use of a hearing aid in their non-implanted ear. A survey of unilaterally implanted adults indicated that those implanted since the publication of NICE guidance were almost seven times more likely to use a hearing aid than those implanted prior to this. If contralateral hearing aid use provides additional benefits over implant use alone, it may be appropriate to consider the capacity to use residual hearing following implantation when determining candidacy.

Magnetically driven middle ear ossicles for optical measurement of vibrations in an ear with opened eardrum

NASA Astrophysics Data System (ADS)

Peacock, John; Von Unge, Magnus; Dirckx, Joris

2012-06-01

Vibrations of the middle ear ossicles are easily measured by means of laser vibrometry. However, exposing the ossicles requires the removal of the eardrum, with the result that the ossicles can no longer be stimulated acoustically. To overcome this we devised a new set up in which the ossicles can be driven magnetically. After measuring the response of the eardrum to an acoustic signal, we then remove the eardrum and attach a small magnet to the exposed manubrium (the part of the first auditory ossicle, the malleus, which is normally attached to the eardrum). An electromagnetic excitation coil is then used to drive the magnet, and the output to the coil adjusted until the vibration of the manubrium, as measured by the vibrometer, matches that measured in response to the acoustic signal. Such a set-up has uses in research on middle ear mechanics, such as the measurement of non-linearities in their response, as well as applications in the diagnosis of middle ear conditions such as the fixation of the ossicles by otosclerosis, or in chronic otitis media. We describe our set up in which the vibrometer unit is attached to a surgical microscope, offering accurate positioning of the laser beam. We discuss the viability of our method and its future potential by presenting some measurements on artificially fixated ears.

Laterality of basic auditory perception.

PubMed

Sininger, Yvonne S; Bhatara, Anjali

2012-01-01

Laterality (left-right ear differences) of auditory processing was assessed using basic auditory skills: (1) gap detection, (2) frequency discrimination, and (3) intensity discrimination. Stimuli included tones (500, 1000, and 4000 Hz) and wide-band noise presented monaurally to each ear of typical adult listeners. The hypothesis tested was that processing of tonal stimuli would be enhanced by left ear (LE) stimulation and noise by right ear (RE) presentations. To investigate the limits of laterality by (1) spectral width, a narrow-band noise (NBN) of 450-Hz bandwidth was evaluated using intensity discrimination, and (2) stimulus duration, 200, 500, and 1000 ms duration tones were evaluated using frequency discrimination. A left ear advantage (LEA) was demonstrated with tonal stimuli in all experiments, but an expected REA for noise stimuli was not found. The NBN stimulus demonstrated no LEA and was characterised as a noise. No change in laterality was found with changes in stimulus durations. The LEA for tonal stimuli is felt to be due to more direct connections between the left ear and the right auditory cortex, which has been shown to be primary for spectral analysis and tonal processing. The lack of a REA for noise stimuli is unexplained. Sex differences in laterality for noise stimuli were noted but were not statistically significant. This study did establish a subtle but clear pattern of LEA for processing of tonal stimuli.

Laterality of Basic Auditory Perception

PubMed Central

Sininger, Yvonne S.; Bhatara, Anjali

2010-01-01

Laterality (left-right ear differences) of auditory processing was assessed using basic auditory skills: 1) gap detection 2) frequency discrimination and 3) intensity discrimination. Stimuli included tones (500, 1000 and 4000 Hz) and wide-band noise presented monaurally to each ear of typical adult listeners. The hypothesis tested was: processing of tonal stimuli would be enhanced by left ear (LE) stimulation and noise by right ear (RE) presentations. To investigate the limits of laterality by 1) spectral width, a narrow band noise (NBN) of 450 Hz bandwidth was evaluated using intensity discrimination and 2) stimulus duration, 200, 500 and 1000 ms duration tones were evaluated using frequency discrimination. Results A left ear advantage (LEA) was demonstrated with tonal stimuli in all experiments but an expected REA for noise stimuli was not found. The NBN stimulus demonstrated no LEA and was characterized as a noise. No change in laterality was found with changes in stimulus durations. The LEA for tonal stimuli is felt to be due to more direct connections between the left ear and the right auditory cortex which has been shown to be primary for spectral analysis and tonal processing. The lack of a REA for noise stimuli is unexplained. Sex differences in laterality for noise stimuli were noted but were not statistically significant. This study did establish a subtle but clear pattern of LEA for processing of tonal stimuli. PMID:22385138

Effects of High Sound Exposure During Air-Conducted Vestibular Evoked Myogenic Potential Testing in Children and Young Adults.

PubMed

Rodriguez, Amanda I; Thomas, Megan L A; Fitzpatrick, Denis; Janky, Kristen L

Vestibular evoked myogenic potential (VEMP) testing is increasingly utilized in pediatric vestibular evaluations due to its diagnostic capability to identify otolith dysfunction and feasibility of testing. However, there is evidence demonstrating that the high-intensity stimulation level required to elicit a reliable VEMP response causes acoustic trauma in adults. Despite utility of VEMP testing in children, similar findings are unknown. It is hypothesized that increased sound exposure may exist in children because differences in ear-canal volume (ECV) compared with adults, and the effect of stimulus parameters (e.g., signal duration and intensity) will alter exposure levels delivered to a child's ear. The objectives of this study are to (1) measure peak to peak equivalent sound pressure levels (peSPL) in children with normal hearing (CNH) and young adults with normal hearing (ANH) using high-intensity VEMP stimuli, (2) determine the effect of ECV on peSPL and calculate a safe exposure level for VEMP, and (3) assess whether cochlear changes exist after VEMP exposure. This was a 2-phase approach. Fifteen CNH and 12 ANH participated in phase I. Equivalent ECV was measured. In 1 ear, peSPL was recorded for 5 seconds at 105 to 125 dB SPL, in 5-dB increments for 500- and 750-Hz tone bursts. Recorded peSPL values (accounting for stimulus duration) were then used to calculate safe sound energy exposure values for VEMP testing using the 132-dB recommended energy allowance from the 2003 European Union Guidelines. Fifteen CNH and 10 ANH received cervical and ocular VEMP testing in 1 ear in phase II. Subjects completed tympanometry, pre- and postaudiometric threshold testing, distortion product otoacoustic emissions, and questionnaire addressing subjective otologic symptoms to study the effect of VEMP exposure on cochlear function. (1) In response to high-intensity stimulation levels (e.g., 125 dB SPL), CNH had significantly higher peSPL measurements and smaller ECVs compared with ANH. (2) A significant linear relationship between equivalent ECV (as measured by diagnostic tympanometry) and peSPL exists and has an effect on total sound energy exposure level; based on data from phase I, 120 dB SPL was determined to be an acoustically safe stimulation level for testing in children. (3) Using calculated safe stimulation level for VEMP testing, there were no significant effect of VEMP exposure on cochlear function (as measured by audiometric thresholds, distortion product otoacoustic emission amplitude levels, or subjective symptoms) in CNH and ANH. peSPL sound recordings in children's ears are significantly higher (~3 dB) than that in adults in response to high-intensity VEMP stimuli that are commonly practiced. Equivalent ECV contributes to peSPL delivered to the ear during VEMP testing and should be considered to determine safe acoustic VEMP stimulus parameters; children with smaller ECVs are at risk for unsafe sound exposure during routine VEMP testing, and stimuli should not exceed 120 dB SPL. Using 120 dB SPL stimulus level for children during VEMP testing yields no change to cochlear function and reliable VEMP responses.

Recognition and Localization of Speech by Adult Cochlear Implant Recipients Wearing a Digital Hearing Aid in the Nonimplanted Ear (Bimodal Hearing)

PubMed Central

Potts, Lisa G.; Skinner, Margaret W.; Litovsky, Ruth A.; Strube, Michael J; Kuk, Francis

2010-01-01

Background The use of bilateral amplification is now common clinical practice for hearing aid users but not for cochlear implant recipients. In the past, most cochlear implant recipients were implanted in one ear and wore only a monaural cochlear implant processor. There has been recent interest in benefits arising from bilateral stimulation that may be present for cochlear implant recipients. One option for bilateral stimulation is the use of a cochlear implant in one ear and a hearing aid in the opposite nonimplanted ear (bimodal hearing). Purpose This study evaluated the effect of wearing a cochlear implant in one ear and a digital hearing aid in the opposite ear on speech recognition and localization. Research Design A repeated-measures correlational study was completed. Study Sample Nineteen adult Cochlear Nucleus 24 implant recipients participated in the study. Intervention The participants were fit with a Widex Senso Vita 38 hearing aid to achieve maximum audibility and comfort within their dynamic range. Data Collection and Analysis Soundfield thresholds, loudness growth, speech recognition, localization, and subjective questionnaires were obtained six–eight weeks after the hearing aid fitting. Testing was completed in three conditions: hearing aid only, cochlear implant only, and cochlear implant and hearing aid (bimodal). All tests were repeated four weeks after the first test session. Repeated-measures analysis of variance was used to analyze the data. Significant effects were further examined using pairwise comparison of means or in the case of continuous moderators, regression analyses. The speech-recognition and localization tasks were unique, in that a speech stimulus presented from a variety of roaming azimuths (140 degree loudspeaker array) was used. Results Performance in the bimodal condition was significantly better for speech recognition and localization compared to the cochlear implant–only and hearing aid–only conditions. Performance was also different between these conditions when the location (i.e., side of the loudspeaker array that presented the word) was analyzed. In the bimodal condition, the speech-recognition and localization tasks were equal regardless of which side of the loudspeaker array presented the word, while performance was significantly poorer for the monaural conditions (hearing aid only and cochlear implant only) when the words were presented on the side with no stimulation. Binaural loudness summation of 1–3 dB was seen in soundfield thresholds and loudness growth in the bimodal condition. Measures of the audibility of sound with the hearing aid, including unaided thresholds, soundfield thresholds, and the Speech Intelligibility Index, were significant moderators of speech recognition and localization. Based on the questionnaire responses, participants showed a strong preference for bimodal stimulation. Conclusions These findings suggest that a well-fit digital hearing aid worn in conjunction with a cochlear implant is beneficial to speech recognition and localization. The dynamic test procedures used in this study illustrate the importance of bilateral hearing for locating, identifying, and switching attention between multiple speakers. It is recommended that unilateral cochlear implant recipients, with measurable unaided hearing thresholds, be fit with a hearing aid. PMID:19594084

Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator

PubMed Central

Luo, Chuan; Omelchenko, Irina; Manson, Robert; Robbins, Carol; Oesterle, Elizabeth C.; Cao, Guo Zhong; Hume, Clifford R.

2015-01-01

Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800 µm by 800 µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24 kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays. PMID:26631107

Alterations in the health of hibernating bats under pathogen pressure.

PubMed

Bandouchova, Hana; Bartonička, Tomáš; Berkova, Hana; Brichta, Jiri; Kokurewicz, Tomasz; Kovacova, Veronika; Linhart, Petr; Piacek, Vladimir; Pikula, Jiri; Zahradníková, Alexandra; Zukal, Jan

2018-04-17

In underground hibernacula temperate northern hemisphere bats are exposed to Pseudogymnoascus destructans, the fungal agent of white-nose syndrome. While pathological and epidemiological data suggest that Palearctic bats tolerate this infection, we lack knowledge about bat health under pathogen pressure. Here we report blood profiles, along with body mass index (BMI), infection intensity and hibernation temperature, in greater mouse-eared bats (Myotis myotis). We sampled three European hibernacula that differ in geomorphology and microclimatic conditions. Skin lesion counts differed between contralateral wings of a bat, suggesting variable exposure to the fungus. Analysis of blood parameters suggests a threshold of ca. 300 skin lesions on both wings, combined with poor hibernation conditions, may distinguish healthy bats from those with homeostatic disruption. Physiological effects manifested as mild metabolic acidosis, decreased glucose and peripheral blood eosinophilia which were strongly locality-dependent. Hibernating bats displaying blood homeostasis disruption had 2 °C lower body surface temperatures. A shallow BMI loss slope with increasing pathogen load suggested a high degree of infection tolerance. European greater mouse-eared bats generally survive P. destructans invasion, despite some health deterioration at higher infection intensities (dependant on hibernation conditions). Conservation measures should minimise additional stressors to conserve constrained body reserves of bats during hibernation.

Gender differences in interhemisphere interactions during distributed and directed attention.

PubMed

Razumnikova, O M; Vol'f, N V

2007-06-01

The role of gender in the functional organization of the hemispheres was studied in relation to the conditions of focusing of attention during the memorization of competitively presented verbal information. Analysis of the reactivity of the coherence of cortical biopotentials in six frequency ranges (4-30 Hz) showed that voluntary selection of information from one auditory channel, as compared with the situation in which attention was distributed between both ears, was accompanied by an increase in the anterofrontal interaction in men and in the parietal-occipital areas of the cortex in the theta1 range in women. In the beta1 range, focusing of attention to the right or left ear during memorizing of words was associated with a contralateral increase in intrahemisphere coherence in men, while there were no significant changes in coherence in women. Changes in coherence in the theta1 and beta1 rhythms, depending on the conditions of distribution of attention and the nature of correlational connections between the reproduction of words and the patterns of reactivity of coherence in these frequency ranges, suggest that word remembering in men is associated mainly with a dominance of regulatory influences from the anterior attention system, while in women it was associated mainly with the posterior system.

TNF-α inhibition using etanercept prevents noise-induced hearing loss by improvement of cochlear blood flow in vivo.

PubMed

Arpornchayanon, Warangkana; Canis, Martin; Ihler, Friedrich; Settevendemie, Claudia; Strieth, Sebastian

2013-08-01

Exposure to loud noise can impair cochlear microcirculation and cause noise-induced hearing loss (NIHL). TNF-α signaling has been shown to be activated in NIHL and to control spiral modiolar artery vasoconstriction that regulates cochlear microcirculation. It was the aim of this experimental study to analyse the effects of the TNF-α inhibitor etanercept on cochlear microcirculation and hearing threshold shift in NIHL in vivo. After assessment of normacusis using ABR, loud noise (106 dB SPL, 30 minutes) was applied on both ears in guinea pigs. Etanercept was administered systemically after loud noise exposure while control animals received a saline solution. In vivo fluorescence microscopy of strial capillaries was performed after surgical exposure of the cochlea for microcirculatory analysis. ABR measurements were derived from the contralateral ear. Guinea pigs (n = 6, per group). Compared to controls, cochlear blood flow in strial capillary segments was significantly increased in etanercept-treated animals. Additionally, hearing threshold was preserved in animals receiving the TNF-α inhibitor in contrast to a significant threshold raising in controls. TNF-α inhibition using etanercept improves cochlear microcirculation and protects hearing levels after loud noise exposure and appears as a promising treatment strategy for human NIHL.

The lack of effect of oxytetracycline on responses to sympathetic nerve stimulation and catecholamines in vascular tissue.

PubMed Central

Kalsner, S

1976-01-01

The effects of oxytetracycline, an inhibitor of amine binding in connective tissue, on the responses of perfused rabbit ear arteries to sympathetic nerve stimulation and to intraluminally administered noradrenaline were examined. The contractions of aortic strips to catecholamines in the presence of oxytetracycline were also examined. Oxytetracycline (0.1 mM) had no discernable effect on the magnitude of constrictions, measured as reductions in flow, produced by either nerve stimulation (0.5-10 Hz) or noradrenaline (0.5-50 ng) in the ear artery. In addition, the time taken for vessels to recover towards control flow values after endogenously released or exogenously applied noradrenaline had acted was not increased by oxytetracycline. Oxytetracycline (0.1 mM) did not alter the position or shape of the concentration-response curve to noradrenaline nor did it enhance the amplitude of individual responses to catecholamines in aortic strips. It is concluded, contrary to the observations of Powis (1973), that oxytetracycline does not increase the magnitude or duration of responses to sympathetic nerve activation or to catecholamines and that binding to connective tissue is of no material consequence in terminating their action in vascular tissue. PMID:974389

Temporal information entropy of the Blood-Oxygenation Level-Dependent signals increases in the activated human primary visual cortex

NASA Astrophysics Data System (ADS)

DiNuzzo, Mauro; Mascali, Daniele; Moraschi, Marta; Bussu, Giorgia; Maraviglia, Bruno; Mangia, Silvia; Giove, Federico

2017-02-01

Time-domain analysis of blood-oxygenation level-dependent (BOLD) signals allows the identification of clusters of voxels responding to photic stimulation in primary visual cortex (V1). However, the characterization of information encoding into temporal properties of the BOLD signals of an activated cluster is poorly investigated. Here, we used Shannon entropy to determine spatial and temporal information encoding in the BOLD signal within the most strongly activated area of the human visual cortex during a hemifield photic stimulation. We determined the distribution profile of BOLD signals during epochs at rest and under stimulation within small (19-121 voxels) clusters designed to include only voxels driven by the stimulus as highly and uniformly as possible. We found consistent and significant increases (2-4% on average) in temporal information entropy during activation in contralateral but not ipsilateral V1, which was mirrored by an expected loss of spatial information entropy. These opposite changes coexisted with increases in both spatial and temporal mutual information (i.e. dependence) in contralateral V1. Thus, we showed that the first cortical stage of visual processing is characterized by a specific spatiotemporal rearrangement of intracluster BOLD responses. Our results indicate that while in the space domain BOLD maps may be incapable of capturing the functional specialization of small neuronal populations due to relatively low spatial resolution, some information encoding may still be revealed in the temporal domain by an increase of temporal information entropy.

Combining functional neuroimaging with off-line brain stimulation: modulation of task-related activity in language areas.

PubMed

Andoh, Jamila; Paus, Tomás

2011-02-01

Repetitive TMS (rTMS) provides a noninvasive tool for modulating neural activity in the human brain. In healthy participants, rTMS applied over the language-related areas in the left hemisphere, including the left posterior temporal area of Wernicke (LTMP) and inferior frontal area of Broca, have been shown to affect performance on word recognition tasks. To investigate the neural substrate of these behavioral effects, off-line rTMS was combined with fMRI acquired during the performance of a word recognition task. Twenty right-handed healthy men underwent fMRI scans before and after a session of 10-Hz rTMS applied outside the magnetic resonance scanner. Functional magnetic resonance images were acquired during the performance of a word recognition task that used English or foreign-language words. rTMS was applied over the LTMP in one group of 10 participants (LTMP group), whereas the homologue region in the right hemisphere was stimulated in another group of 10 participants (RTMP group). Changes in task-related fMRI response (English minus foreign languages) and task performances (response time and accuracy) were measured in both groups and compared between pre-rTMS and post-rTMS. Our results showed that rTMS increased task-related fMRI response in the homologue areas contralateral to the stimulated sites. We also found an effect of rTMS on response time for the LTMP group only. These findings provide insights into changes in neural activity in cortical regions connected to the stimulated site and are consistent with a hypothesis raised in a previous review about the role of the homologue areas in the contralateral hemisphere for preserving behavior after neural interference.

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes.

PubMed

Stöckel, Tino; Carroll, Timothy J; Summers, Jeffery J; Hinder, Mark R

2016-08-01

Performance benefits conferred in the untrained limb after unilateral motor practice are termed cross-limb transfer. Although the effect is robust, the neural mechanisms remain incompletely understood. In this study we used noninvasive brain stimulation to reveal that the neural adaptations that mediate motor learning in the trained limb are distinct from those that underlie cross-limb transfer to the opposite limb. Thirty-six participants practiced a ballistic motor task with their right index finger (150 trials), followed by intermittent theta-burst stimulation (iTBS) applied to the trained (contralateral) primary motor cortex (cM1 group), the untrained (ipsilateral) M1 (iM1 group), or the vertex (sham group). After stimulation, another 150 training trials were undertaken. Motor performance and corticospinal excitability were assessed before motor training, pre- and post-iTBS, and after the second training bout. For all groups, training significantly increased performance and excitability of the trained hand, and performance, but not excitability, of the untrained hand, indicating transfer at the level of task performance. The typical facilitatory effect of iTBS on MEPs was reversed for cM1, suggesting homeostatic metaplasticity, and prior performance gains in the trained hand were degraded, suggesting that iTBS interfered with learning. In stark contrast, iM1 iTBS facilitated both performance and excitability for the untrained hand. Importantly, the effects of cM1 and iM1 iTBS on behavior were exclusive to the hand contralateral to stimulation, suggesting that adaptations within the untrained M1 contribute to cross-limb transfer. However, the neural processes that mediate learning in the trained hemisphere vs. transfer in the untrained hemisphere appear distinct. Copyright © 2016 the American Physiological Society.

Motor learning and cross-limb transfer rely upon distinct neural adaptation processes

PubMed Central

Carroll, Timothy J.; Summers, Jeffery J.; Hinder, Mark R.

2016-01-01

Performance benefits conferred in the untrained limb after unilateral motor practice are termed cross-limb transfer. Although the effect is robust, the neural mechanisms remain incompletely understood. In this study we used noninvasive brain stimulation to reveal that the neural adaptations that mediate motor learning in the trained limb are distinct from those that underlie cross-limb transfer to the opposite limb. Thirty-six participants practiced a ballistic motor task with their right index finger (150 trials), followed by intermittent theta-burst stimulation (iTBS) applied to the trained (contralateral) primary motor cortex (cM1 group), the untrained (ipsilateral) M1 (iM1 group), or the vertex (sham group). After stimulation, another 150 training trials were undertaken. Motor performance and corticospinal excitability were assessed before motor training, pre- and post-iTBS, and after the second training bout. For all groups, training significantly increased performance and excitability of the trained hand, and performance, but not excitability, of the untrained hand, indicating transfer at the level of task performance. The typical facilitatory effect of iTBS on MEPs was reversed for cM1, suggesting homeostatic metaplasticity, and prior performance gains in the trained hand were degraded, suggesting that iTBS interfered with learning. In stark contrast, iM1 iTBS facilitated both performance and excitability for the untrained hand. Importantly, the effects of cM1 and iM1 iTBS on behavior were exclusive to the hand contralateral to stimulation, suggesting that adaptations within the untrained M1 contribute to cross-limb transfer. However, the neural processes that mediate learning in the trained hemisphere vs. transfer in the untrained hemisphere appear distinct. PMID:27169508

The right hemisphere is independent from the left hemisphere in allocating visuospatial attention.

PubMed

Zuanazzi, Arianna; Cattaneo, Luigi

2017-07-28

The capacity to allocate visuospatial attention is traditionally considered right-lateralized according to the effects of unilateral cerebral lesions. Contralateral hemi-spatial neglect occurs much more frequently after lesions of the right hemisphere, which has therefore been dubbed as 'dominant'. This pattern of symptoms is supported by functional models that postulate either independence or reciprocal influences between the two hemispheres. Here we specifically explored the dependency of the right hemisphere (RH) from the left hemisphere (LH) in spatial attention. We capitalized on the well-known effect of online transcranial magnetic stimulation (TMS) on the RH in healthy individuals, consisting in transient neglect-like manifestations in the left hemi-space. We assessed whether prior stimulation of the left posterior parietal cortex with a long-lasting neuromodulatory procedure (transcranial direct current stimulation - tDCS) affected the acute effects of TMS on the right posterior parietal cortex. We performed a within-subjects factorial study with two factors: LH tDCS (sham or real) and RH TMS (sham or real), resulting in a 2×2 design. The effects on spatial attention were examined separately for the two hemi-spaces by means of a modified line-bisection task. The results indicated that TMS over the RH produced a spatial attention deficit in the left hemi-space alone and the behavioural effects of TMS were not modulated by prior stimulation of the LH. Interestingly, additional analyses showed that tDCS over the LH alone produced a deficit in spatial attention to the right hemi-space. We interpret the current results as evidence for a largely independent contribution of each hemisphere to the allocation of visuospatial attention limited to the contralateral hemi-space. Copyright © 2017 Elsevier Ltd. All rights reserved.

Attentional load and sensory competition in human vision: modulation of fMRI responses by load at fixation during task-irrelevant stimulation in the peripheral visual field.

PubMed

Schwartz, Sophie; Vuilleumier, Patrik; Hutton, Chloe; Maravita, Angelo; Dolan, Raymond J; Driver, Jon

2005-06-01

Perceptual suppression of distractors may depend on both endogenous and exogenous factors, such as attentional load of the current task and sensory competition among simultaneous stimuli, respectively. We used functional magnetic resonance imaging (fMRI) to compare these two types of attentional effects and examine how they may interact in the human brain. We varied the attentional load of a visual monitoring task performed on a rapid stream at central fixation without altering the central stimuli themselves, while measuring the impact on fMRI responses to task-irrelevant peripheral checkerboards presented either unilaterally or bilaterally. Activations in visual cortex for irrelevant peripheral stimulation decreased with increasing attentional load at fixation. This relative decrease was present even in V1, but became larger for successive visual areas through to V4. Decreases in activation for contralateral peripheral checkerboards due to higher central load were more pronounced within retinotopic cortex corresponding to 'inner' peripheral locations relatively near the central targets than for more eccentric 'outer' locations, demonstrating a predominant suppression of nearby surround rather than strict 'tunnel vision' during higher task load at central fixation. Contralateral activations for peripheral stimulation in one hemifield were reduced by competition with concurrent stimulation in the other hemifield only in inferior parietal cortex, not in retinotopic areas of occipital visual cortex. In addition, central attentional load interacted with competition due to bilateral versus unilateral peripheral stimuli specifically in posterior parietal and fusiform regions. These results reveal that task-dependent attentional load, and interhemifield stimulus-competition, can produce distinct influences on the neural responses to peripheral visual stimuli within the human visual system. These distinct mechanisms in selective visual processing may be integrated within posterior parietal areas, rather than earlier occipital cortex.

BA3b and BA1 activate in a serial fashion after median nerve stimulation: direct evidence from combining source analysis of evoked fields and cytoarchitectonic probabilistic maps.

PubMed

Papadelis, Christos; Eickhoff, Simon B; Zilles, Karl; Ioannides, Andreas A

2011-01-01

This study combines source analysis imaging data for early somatosensory processing and the probabilistic cytoarchitectonic maps (PCMs). Human somatosensory evoked fields (SEFs) were recorded by stimulating left and right median nerves. Filtering the recorded responses in different frequency ranges identified the most responsive frequency band. The short-latency averaged SEFs were analyzed using a single equivalent current dipole (ECD) model and magnetic field tomography (MFT). The identified foci of activity were superimposed with PCMs. Two major components of opposite polarity were prominent around 21 and 31 ms. A weak component around 25 ms was also identified. For the most responsive frequency band (50-150 Hz) ECD and MFT revealed one focal source at the contralateral Brodmann area 3b (BA3b) at the peak of N20. The component ~25 ms was localised in Brodmann area 1 (BA1) in 50-150 Hz. By using ECD, focal generators around 28-30 ms located initially in BA3b and 2 ms later to BA1. MFT also revealed two focal sources - one in BA3b and one in BA1 for these latencies. Our results provide direct evidence that the earliest cortical response after median nerve stimulation is generated within the contralateral BA3b. BA1 activation few milliseconds later indicates a serial mode of somatosensory processing within cytoarchitectonic SI subdivisions. Analysis of non-invasive magnetoencephalography (MEG) data and the use of PCMs allow unambiguous and quantitative (probabilistic) interpretation of cytoarchitectonic identity of activated areas following median nerve stimulation, even with the simple ECD model, but only when the model fits the data extremely well. Copyright © 2010 Elsevier Inc. All rights reserved.

Sensory Feedback in Interlimb Coordination: Contralateral Afferent Contribution to the Short-Latency Crossed Response during Human Walking.

PubMed

Gervasio, Sabata; Voigt, Michael; Kersting, Uwe G; Farina, Dario; Sinkjær, Thomas; Mrachacz-Kersting, Natalie

2017-01-01

A constant coordination between the left and right leg is required to maintain stability during human locomotion, especially in a variable environment. The neural mechanisms underlying this interlimb coordination are not yet known. In animals, interneurons located within the spinal cord allow direct communication between the two sides without the need for the involvement of higher centers. These may also exist in humans since sensory feedback elicited by tibial nerve stimulation on one side (ipsilateral) can affect the muscles activation in the opposite side (contralateral), provoking short-latency crossed responses (SLCRs). The current study investigated whether contralateral afferent feedback contributes to the mechanism controlling the SLCR in human gastrocnemius muscle. Surface electromyogram, kinematic and kinetic data were recorded from subjects during normal walking and hybrid walking (with the legs moving in opposite directions). An inverse dynamics model was applied to estimate the gastrocnemius muscle proprioceptors' firing rate. During normal walking, a significant correlation was observed between the magnitude of SLCRs and the estimated muscle spindle secondary afferent activity (P = 0.04). Moreover, estimated spindle secondary afferent and Golgi tendon organ activity were significantly different (P ≤ 0.01) when opposite responses have been observed, that is during normal (facilitation) and hybrid walking (inhibition) conditions. Contralateral sensory feedback, specifically spindle secondary afferents, likely plays a significant role in generating the SLCR. This observation has important implications for our understanding of what future research should be focusing on to optimize locomotor recovery in patient populations.

Asymmetric Hearing During Development: The Aural Preference Syndrome and Treatment Options.

PubMed

Gordon, Karen; Henkin, Yael; Kral, Andrej

2015-07-01

Deafness affects ∼2 in 1000 children and is one of the most common congenital impairments. Permanent hearing loss can be treated by fitting hearing aids. More severe to profound deafness is an indication for cochlear implantation. Although newborn hearing screening programs have increased the identification of asymmetric hearing loss, parents and caregivers of children with single-sided deafness are often hesitant to pursue therapy for the deaf ear. Delayed intervention has consequences for recovery of hearing. It has long been reported that asymmetric hearing loss/single-sided deafness compromises speech and language development and educational outcomes in children. Recent studies in animal models of deafness and in children consistently show evidence of an "aural preference syndrome" in which single-sided deafness in early childhood reorganizes the developing auditory pathways toward the hearing ear, with weaker central representation of the deaf ear. Delayed therapy consequently compromises benefit for the deaf ear, with slow rates of improvement measured over time. Therefore, asymmetric hearing needs early identification and intervention. Providing early effective stimulation in both ears through appropriate fitting of auditory prostheses, including hearing aids and cochlear implants, within a sensitive period in development has a cardinal role for securing the function of the impaired ear and for restoring binaural/spatial hearing. The impacts of asymmetric hearing loss on the developing auditory system and on spoken language development have often been underestimated. Thus, the traditional minimalist approach to clinical management aimed at 1 functional ear should be modified on the basis of current evidence. Copyright © 2015 by the American Academy of Pediatrics.

Insecticidal activity of common reagents for insect foreign bodies of the ear.

PubMed

Antonelli, P J; Ahmadi, A; Prevatt, A

2001-01-01

Insects commonly present as painful and distressing foreign bodies of the external ear canal. Removing live insects can be challenging, especially for primary care physicians who have limited equipment. The purpose of this study is to compare the insecticidal activity of commonly available preparations for insects that are most frequently recovered from ear canals: cockroaches (German and American), ticks, beetles, and honeybees. Prospective, blinded. One hundred seventy insects of each species were placed in test tubes and submerged in 17 test preparations (10 tubes per preparation, 1 insect per test tube). Insect activity was stimulated by agitation of the test tube. Responses were monitored, and the time until death was measured. Most test preparations exhibited some insecticidal activity against most insect species. Ticks were completely resistant to all of the test reagents. Ethanol killed the American cockroaches (mean time, 32.6 s), German cockroaches (mean time, 29.6 s), and honeybees (mean time, 19.6 s) the most rapidly. Many commonly available reagents may be used to kill or immobilize insect foreign bodies of the ear.

Achilles tendon vibration-induced changes in plantar flexor corticospinal excitability.

PubMed

Lapole, Thomas; Temesi, John; Gimenez, Philippe; Arnal, Pierrick J; Millet, Guillaume Y; Petitjean, Michel

2015-02-01

Daily Achilles tendon vibration has been shown to increase muscle force, likely via corticospinal neural adaptations. The aim of the present study was to determine the extent by which corticospinal excitability is influenced during direct Achilles tendon vibration. Motor-evoked potentials (MEPs) were elicited in the soleus (SOL), gastrocnemius medialis (GM) and tibialis anterior (TA) by transcranial magnetic stimulation of the motor cortical area of the leg with and without Achilles tendon vibration at various frequencies (50, 80 and 110 Hz). Contralateral homologues were also investigated. SOL and GM MEP amplitude significantly increased by 226 ± 188 and 66 ± 39%, respectively, during Achilles tendon vibration, without any difference between the tested frequencies. No MEP changes were reported for TA or contralateral homologues. Increased SOL and GM MEP amplitude suggests increased vibration-induced corticospinal excitability independent of vibration frequency.

The Coordinated Noninvasive Studies (CNS) Project. Phase 1. Appendices

DTIC Science & Technology

1991-12-01

34Bandwidth of three-element patterns and its effect on relative ear advantages," to Acoustical Society of America, Cincinnati. Abstract: J Acoust Soc Amer...Acoustical Society of America, Cincinnati. Abstract: J Acoust Soc Amer 73: S60. "Cerebral metabolic effects of auditory stimulation," to Brain Breakfast...Laboratory, Los Alamos NM. "PET and the cortex: the effects of auditory stimulation on cerebral blood flow," to Department of Speech and Hearing Sciences

Citrus hallabong [(Citrus unshiu × C. sinensis) × C. reticulata)] exerts potent anti-inflammatory properties in murine splenocytes and TPA-induced murine ear oedema model.

PubMed

Herath, Kalahe Hewage Iresha Nadeeka Madushani; Bing, So Jin; Cho, Jinhee; Kim, Areum; Kim, Gi-Ok; Lee, Jong-Chul; Jee, Youngheun

2016-12-01

Hallabong [(Citrus unshiu × C. sinensis) X C. reticulata)] (Rutaceae) is a hybrid citrus cultivated in temperate regions of South Korea. Its fruit is well-known for pharmacological properties. This study examined the anti-inflammatory effect of 80% ethanol extract of Hallabong (HE) on concanavalin A (Con A)-stimulated splenocytes and mouse oedema model induced by 12-O-tetradecanoylphorbal acetate (TPA). Murine splenocytes treated with HE were stimulated with Con A (10 μg/mL, for 24 h) were evaluated for T-cell population and production of inflammatory cytokines IL-2, IL-4 and IFN-γ. Anti-inflammatory effect of topically applied HE (100 μg/20 μL) on TPA (4 μg/20 μL/ear)-induced ear oedema was investigated in mouse model. HE-treated Con A-stimulated murine splenocytes showed a marked decrease in CD44/CD62L + memory T-cell population, an important marker for anti-inflammatory activity, and a significant inhibition in the production of IL-2 and IFN-γ. HE treatment had reduced the mouse skin oedema (47%) and myeloperoxidase (MPO) activity significantly (40%) in TPA-challenged tissues. More importantly, immunohistochemical localization revealed the suppressed (p < 0.05) expression of inducible nitric oxide (iNOS), cyclooxygenase-2 (COX2). HE decreased the infiltration of CD3 + T cells and F4/80 + macrophages to the site of inflammation and a topical application of HE significantly suppressed the expression of TNF-α (20.2%). A topical application of HE can exert a potential anti-inflammatory effect and HE can be explored further as a putative alternative therapeutic agent for inflammatory oedema.

Effect of bradykinin antagonists on bradykinin-induced plasma extravasation, venoconstriction, prostaglandin E2 release, nociceptor stimulation and contraction of the iris sphincter muscle in the rabbit.

PubMed Central

Griesbacher, T.; Lembeck, F.

1987-01-01

1 The inhibition of the bradykinin-induced plasma extravasation by six bradykinin (Bk) antagonists was tested on rabbit skin. All of them showed inhibitory effects without an agonistic action in the does used. B4310 (Lys-Lys-3-Hyp-5,8-Thi-7-DPhe-Bk) was the most active antagonist and was therefore used in the subsequent experiments. 2 B4310 (5-500 nM) antagonized the bradykinin-induced reduction of the venous outflow from the rabbit isolated ear in dose-dependent manner without affecting the arterial vasoconstriction induced by angiotensin II. 3 The bradykinin-induced release of prostaglandin E2 (PGE2) from the perfused rabbit ear was reduced by 63% when B4310 (800 nM) was infused before, during and after the bradykinin injection. 4 Bradykinin was injected into the ear artery of anaesthetized rabbits and the reflex hypotensive response was used as indicator of the nociception. The response was antagonized by a local infusion of B4310 (50 and 500 nM). The antagonism was dose-dependent and reversible. The parallel shift of the dose-response curve to bradykinin suggests a competitive inhibition. However, B4310 did not antagonize acetylcholine-induced nociceptor stimulation. 5 B4310 inhibited bradykinin-induced stimulation of the trigeminal nerve which results in a substance P-mediated contraction of the iris sphincter muscle. A pA2 of 7.59 was calculated. B4310 did not inhibit capsaicin-induced contractions. 6 It is concluded that B4310 inhibits specifically five different actions of bradykinin which are related to its possible pathophysiological role. PMID:3479223

Hemispheric asymmetry of auditory steady-state responses to monaural and diotic stimulation.

PubMed

Poelmans, Hanne; Luts, Heleen; Vandermosten, Maaike; Ghesquière, Pol; Wouters, Jan

2012-12-01

Amplitude modulations in the speech envelope are crucial elements for speech perception. These modulations comprise the processing rate at which syllabic (~3-7 Hz), and phonemic transitions occur in speech. Theories about speech perception hypothesize that each hemisphere in the auditory cortex is specialized in analyzing modulations at different timescales, and that phonemic-rate modulations of the speech envelope lateralize to the left hemisphere, whereas right lateralization occurs for slow, syllabic-rate modulations. In the present study, neural processing of phonemic- and syllabic-rate modulations was investigated with auditory steady-state responses (ASSRs). ASSRs to speech-weighted noise stimuli, amplitude modulated at 4, 20, and 80 Hz, were recorded in 30 normal-hearing adults. The 80 Hz ASSR is primarily generated by the brainstem, whereas 20 and 4 Hz ASSRs are mainly cortically evoked and relate to speech perception. Stimuli were presented diotically (same signal to both ears) and monaurally (one signal to the left or right ear). For 80 Hz, diotic ASSRs were larger than monaural responses. This binaural advantage decreased with decreasing modulation frequency. For 20 Hz, diotic ASSRs were equal to monaural responses, while for 4 Hz, diotic responses were smaller than monaural responses. Comparison of left and right ear stimulation demonstrated that, with decreasing modulation rate, a gradual change from ipsilateral to right lateralization occurred. Together, these results (1) suggest that ASSR enhancement to binaural stimulation decreases in the ascending auditory system and (2) indicate that right lateralization is more prominent for low-frequency ASSRs. These findings may have important consequences for electrode placement in clinical settings, as well as for the understanding of low-frequency ASSR generation.

Auricular syncope.

PubMed

Thakar, A; Deepak, K K; Kumar, S Shyam

2008-10-01

To describe a previously unreported syndrome of recurrent syncopal attacks provoked by light stimulation of the external auditory canal. A 13-year-old girl had been receiving treatment for presumed absence seizures, with inadequate treatment response. Imaging was normal. Careful history taking indicated that the recurrent syncopal attacks were precipitated by external auditory canal stimulation. Targeted autonomic function tests confirmed a hyperactive vagal response, with documented significant bradycardia and lightheadedness, provoked by mild stimulation of the posterior wall of the left external auditory canal. Abstinence from ear scratching led to complete alleviation of symptoms without any pharmacological treatment. Reflex syncope consequent to stimulation of the auricular branch of the vagus nerve is proposed as the pathophysiological mechanism for this previously undocumented syndrome.

Inner ear lesion and the differential roles of hypoxia and hypercarbia in triggering active movements: Potential implication for the Sudden Infant Death Syndrome.

PubMed

Ramirez, Sanja; Allen, Travis; Villagracia, Lindsay; Chae, Yooree; Ramirez, Jan M; Rubens, Daniel D

2016-11-19

Infants that succumb to Sudden Infant Death Syndrome (SIDS) have been identified with inner ear dysfunction (IED) at birth and on autopsy. We previously investigated whether IED could play a mechanistic role in SIDS. We discovered that animals with IED displayed significant suppression of movement arousal to a hypoxic-hypercarbic gas mixture under light anesthesia. In the current study we investigated the role of each gas in triggering movements and the response to hypercarbia during natural sleep without anesthesia. Seventeen-day-old CD-1 mice received intra-tympanic gentamicin (IT-Gent) injections to precipitate IED. The movement response to hypercarbia, hypoxia and hypoxia-hypercarbia was compared to controls under light anesthesia. Hypercarbia did not stimulate vigorous movements in any animals under either sleep condition. Hypoxia triggered vigorous movements in controls (p<0.05) and a decreased response in IT-Gent animals under light anesthesia. This contrasted with combined hypoxia-hypercarbia, in which IT-Gent animals displaced significantly suppressed movements compared to controls (p<0.05). Our findings portray that a degree of intact inner ear function is necessary for instigating the movement response. Additionally, hypoxia is the trigger for the movement response while carbon dioxide (CO 2 ) suppresses it. The finding that carbon dioxide did not stimulate movement during natural sleep is an important finding. This contrasts with other studies that have identified hypercarbia as an arousal stimulus with EEG. Further studies are warranted to evaluate the precise role of the inner ear in the movement response and potential association with SIDS. The early detection of IED in SIDS predisposed cases could be invaluable. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Curcumin inhibits epigen and amphiregulin upregulated by 2,4,6-trinitrochlorobenzene associated with attenuation of skin swelling.

PubMed

Sakai, Hiroyasu; Sato, Ken; Sato, Fumiaki; Kai, Yuki; Mandokoro, Kazutaka; Matsumoto, Kenjiro; Kato, Shinichi; Yumoto, Tetsuro; Narita, Minoru; Chiba, Yoshihiko

2017-08-01

Contact dermatitis model involving repeated application of hapten is used as a tool to assess dermatitis, as characterized by thickening. Involvement of cell proliferation, elicited by repeated hapten-stimulation, in this swelling has been unclear. Curcumin is reported to reduce inflammation. We examined involvement of cell proliferation and the role of extracellular regulated kinase (ERK) in 2,4,6-trinitrochlorobenzene (TNCB) challenge-induced ear swelling. We also examined the effects of curcumin in this model. Mice were sensitized with TNCB to the abdominal skin. Then, they were challenged with TNCB to the ear three times. The ERK activation inhibitor U0126 or curcumin was applied 30 min before each TNCB challenge. TNCB challenge-induced increased epidermal cell number and dermal thickening. Gene expressions of epithelial mitogen (EPGN), amphiregulin (AREG) and heparin-binding-epidermal growth factor (HB-EGF) were increased in the ears after the last TNCB challenge. Ki-67 immunoreactivity was increased in the dermis in TNCB-challenged ears. TNCB-induced swelling was inhibited by U0126 and curcumin. Curcumin also attenuated TNCB-induced ERK phosphorylation and expression of EPGN and AREG genes. Ear swelling induced by TNCB challenge might be mediated, in part, by the EPGN- and AREG-ERK proliferation pathway and was inhibited by curcumin.

THE POTENTIAL ROLE OF ENDOGENOUS STEM CELLS IN REGENERATION OF THE INNER EAR

PubMed Central

Martinez-Monedero, Rodrigo; Oshima, Kazuo; Heller, Stefan; Edge, Albert S.B.

2007-01-01

Stem cells in various mammalian tissues retain the capacity to renew themselves and may be able to restore damaged tissue. Their existence has been proven by genetic tracer studies that demonstrate their differentiation into multiple tissue types and by their ability to self-renew through proliferation. Stem cells from the adult nervous system proliferate to form clonal floating colonies called spheres in vitro, and recent studies have demonstrated sphere formation by cells in the cochlea in addition to the vestibular system and the auditory ganglia, indicating that these tissues contain cells with stem cell properties. The presence of stem cells in the inner ear raises the hope of regeneration of mammalian inner ear cells but is difficult to correlate with the lack spontaneous regeneration seen in the inner ear after tissue damage. Loss of stem cells postnatally in the cochlea may correlate with the loss of regenerative capacity and may limit our ability to stimulate regeneration. Retention of sphere forming capacity in adult vestibular tissues suggests that the limited capacity for repair may be attributed to the continued presence of progenitor cells. Future strategies for regeneration must consider the distribution of endogenous stem cells in the inner ear and whether cells with the capacity for regeneration are retained. PMID:17321086

Effect of transcranial direct current stimulation on vestibular-ocular and vestibulo-perceptual thresholds.

PubMed

Kyriakareli, Artemis; Cousins, Sian; Pettorossi, Vito E; Bronstein, Adolfo M

2013-10-02

Transcranial direct current stimulation (tDCS) was used in 17 normal individuals to modulate vestibulo-ocular reflex (VOR) and self-motion perception rotational thresholds. The electrodes were applied over the temporoparietal junction bilaterally. Both vestibular nystagmic and perceptual thresholds were increased during as well as after tDCS stimulation. Body rotation was labeled as ipsilateral or contralateral to the anode side, but no difference was observed depending on the direction of rotation or hemisphere polarity. Threshold increase during tDCS was greater for VOR than for motion perception. 'Sham' stimulation had no effect on thresholds. We conclude that tDCS produces an immediate and sustained depression of cortical regions controlling VOR and movement perception. Temporoparietal areas appear to be involved in vestibular threshold modulation but the differential effects observed between VOR and perception suggest a partial dissociation between cortical processing of reflexive and perceptual responses.

Dynamic oscillatory processes governing cued orienting and allocation of auditory attention

PubMed Central

Ahveninen, Jyrki; Huang, Samantha; Belliveau, John W.; Chang, Wei-Tang; Hämäläinen, Matti

2013-01-01

In everyday listening situations, we need to constantly switch between alternative sound sources and engage attention according to cues that match our goals and expectations. The exact neuronal bases of these processes are poorly understood. We investigated oscillatory brain networks controlling auditory attention using cortically constrained fMRI-weighted magnetoencephalography/ electroencephalography (MEG/EEG) source estimates. During consecutive trials, subjects were instructed to shift attention based on a cue, presented in the ear where a target was likely to follow. To promote audiospatial attention effects, the targets were embedded in streams of dichotically presented standard tones. Occasionally, an unexpected novel sound occurred opposite to the cued ear, to trigger involuntary orienting. According to our cortical power correlation analyses, increased frontoparietal/temporal 30–100 Hz gamma activity at 200–1400 ms after cued orienting predicted fast and accurate discrimination of subsequent targets. This sustained correlation effect, possibly reflecting voluntary engagement of attention after the initial cue-driven orienting, spread from the temporoparietal junction, anterior insula, and inferior frontal (IFC) cortices to the right frontal eye fields. Engagement of attention to one ear resulted in a significantly stronger increase of 7.5–15 Hz alpha in the ipsilateral than contralateral parieto-occipital cortices 200–600 ms after the cue onset, possibly reflecting crossmodal modulation of the dorsal visual pathway during audiospatial attention. Comparisons of cortical power patterns also revealed significant increases of sustained right medial frontal cortex theta power, right dorsolateral prefrontal cortex and anterior insula/IFC beta power, and medial parietal cortex and posterior cingulate cortex gamma activity after cued vs. novelty-triggered orienting (600–1400 ms). Our results reveal sustained oscillatory patterns associated with voluntary engagement of auditory spatial attention, with the frontoparietal and temporal gamma increases being best predictors of subsequent behavioral performance. PMID:23915050

The Clinical Utility of Vestibular Evoked Myogenic Potentials in Patients of Benign Paroxysmal Positional Vertigo.

PubMed

Sreenivasan, Anuprasad; Sivaraman, Ganesan; Parida, Pradiptata Kumar; Alexander, Arun; Saxena, Sunil Kumar; Suria, Gopalakrishnan

2015-06-01

Vestibular Evoked Myogenic Potentials (VEMP) is an emerging tool to diagnose Benign Paroxysmal Positional Vertigo (BPPV). The clinical utility of VEMP has been reported only in small accord in Indian literature. To study the latency and amplitude of VEMP in patients with BPPV and compare it with that of normal subjects. The study included two groups. Group one (control group) were 18 normal subjects. Group two (test group) were 15 subjects with unilateral BPPV. Those subjects who fulfilled the selection criteria based on case history and audiological assessment were taken for the VEMP recording. The VEMP response consist of positive and negative successive waves (pI-nI), with latency values in adults about 13 and 23 milliseconds respectively. Data was analysed using Statistical Package for Social Sciences (SPSS) version 12 (Chicago, IL, USA). Unpaired t-test was employed to measure the statistical difference between control group and test group. The difference in n23 and the peak to peak amplitude between the ipsilateral and contralateral ears of the test group were statistically significant, whereas such a difference in the p13 latency turned out to be statistically insignificant. It should be noted that, out of 15 patients in the test group, five patients showed only artifact tracer recordings in both the ears which is considered as no response. The heterogeneity of the results extended from absence of VEMP to prolongation of both p13, n23; prolongation of p13 alone; and even side to side variations. Absent response from the ipsilateral ear, prolonged latency of n23 and decreased peak to peak amplitude (p13, n23), indicates the disease pathology. However, large sample size is required to draw further conclusions and to consolidate the usage of VEMP in the diagnosis of BPPV.

Contralesional Cathodal versus Dual Transcranial Direct Current Stimulation for Decreasing Upper Limb Spasticity in Chronic Stroke Individuals: A Clinical and Neurophysiological Study.

PubMed

Del Felice, Alessandra; Daloli, Verena; Masiero, Stefano; Manganotti, Paolo

2016-12-01

Different transcranial direct current stimulation (tDCS) paradigms have been implemented to treat poststroke spasticity, but discordant results have been reported. This study aimed to determine the efficacy and persistence of dual tDCS (anode over affected motor cortex [M1] and cathode over contralateral M1) compared with cathodal tDCS (cathode over contralateral M1) on upper limb (UL) functional, behavioral, and neurophysiological measures in chronic poststroke individuals. Ten subjects with UL spasticity (7 men; mean 62 years; 8 ischemic stroke; years from event: 2.3 years) were enrolled in a cross-over, double-blinded study. Cathodal and dual tDCS, both preceded by 1 week of sham stimulation 1 month before real stimulation, were applied with 3 months interval. Stimulating paradigm was 20 minutes for five consecutive days in each block. Evaluations were performed before (T1), after real or sham treatment (T2), and after 1 (T3), 4 (T4), and 8 weeks (T5). Functional, behavioral, and neurophysiological tests were performed at each time. Both tDCS paradigms decreased spasticity, increased strength, and ameliorated behavioral scales. Cathodal tDCS was superior to dual tDCS in reducing UL distal spasticity immediately after treatment (T2: cathodal > dual: P = .023) and provided a higher and longer lasting reduction at proximal districts (T3: cathodal > dual: P = .042; T4: cathodal > dual: P = .028; T5: cathodal > dual: P = .05). These findings are supported by an H-reflex modulation (overall time effect P > .002). Cathodal tDCS is slightly more effective than dual tDCS in reducing distal UL spasticity in chronic poststroke subjects. A modulation of spinal inhibitory mechanisms, demonstrated by H-reflex modifications, supports this finding. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Parameter Optimization Analysis of Prolonged Analgesia Effect of tDCS on Neuropathic Pain Rats

PubMed Central

Wen, Hui-Zhong; Gao, Shi-Hao; Zhao, Yan-Dong; He, Wen-Juan; Tian, Xue-Long; Ruan, Huai-Zhen

2017-01-01

Background: Transcranial direct current stimulation (tDCS) is widely used to treat human nerve disorders and neuropathic pain by modulating the excitability of cortex. The effectiveness of tDCS is influenced by its stimulation parameters, but there have been no systematic studies to help guide the selection of different parameters. Objective: This study aims to assess the effects of tDCS of primary motor cortex (M1) on chronic neuropathic pain in rats and to test for the optimal parameter combinations for analgesia. Methods: Using the chronic neuropathic pain models of chronic constriction injury (CCI), we measured pain thresholds before and after anodal-tDCS (A-tDCS) using different parameter conditions, including stimulation intensity, stimulation time, intervention time and electrode located (ipsilateral or contralateral M1 of the ligated paw on male/female CCI models). Results: Following the application of A-tDCS over M1, we observed that the antinociceptive effects were depended on different parameters. First, we found that repetitive A-tDCS had a longer analgesic effect than single stimulus, and both ipsilateral-tDCS (ip-tDCS) and contralateral-tDCS (con-tDCS) produce a long-lasting analgesic effect on neuropathic pain. Second, the antinociceptive effects were intensity-dependent and time-dependent, high intensities worked better than low intensities and long stimulus durations worked better than short stimulus durations. Third, timing of the intervention after injury affected the stimulation outcome, early use of tDCS was an effective method to prevent the development of pain, and more frequent intervention induced more analgesia in CCI rats, finally, similar antinociceptive effects of con- and ip-tDCS were observed in both sexes of CCI rats. Conclusion: Optimized protocols of tDCS for treating antinociceptive effects were developed. These findings should be taken into consideration when using tDCS to produce analgesic effects in clinical applications. PMID:28659772

Contralaterally Controlled Functional Electrical Stimulation Improves Hand Dexterity in Chronic Hemiparesis: A Randomized Trial

PubMed Central

Knutson, Jayme S.; Gunzler, Douglas D.; Wilson, Richard D.; Chae, John

2016-01-01

Background and Purpose It is unknown whether one method of neuromuscular stimulation for post-stroke upper limb rehabilitation is more effective than another. Our aim was to compare the effects of contralaterally controlled functional electrical stimulation (CCFES) to cyclic neuromuscular electrical stimulation (cNMES). Methods Stroke patients with chronic (> 6 months) moderate to severe upper extremity hemiparesis (n=80) were randomized to receive 10 sessions/week of CCFES- or cNMES-assisted hand opening exercise at home plus 20 sessions of functional task practice in the lab over 12 weeks. The task practice for the CCFES group was stimulation-assisted. The primary outcome was change in Box and Blocks Test (BBT) score at 6-months post-treatment. Upper extremity Fugl-Meyer (UEFM) and Arm Motor Abilities Test (AMAT) were also measured. Results At 6-months post-treatment, the CCFES group had greater improvement on the BBT, 4.6 (95% CI: 2.2, 7.0), than the cNMES group, 1.8 (95% CI: 0.6, 3.0); between-group difference, 2.8 (95% CI: 0.1, 5.5), p=0.045. No significant between-group difference was found for the UEFM (p=.888) or AMAT (p=.096). Participants who had the largest improvements on BBT were less than two years post-stroke with moderate (i.e., not severe) hand impairment at baseline. Among these, the 6-month post-treatment BBT gains of the CCFES group, 9.6 (95% CI: 5.6, 13.6), were greater than those of the cNMES group, 4.1 (95% CI: 1.7, 6.5); between-group difference, 5.5 (95% CI: 0.8, 10.2), p=0.023. Conclusions CCFES improved hand dexterity more than cNMES in chronic stroke survivors. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00891319. PMID:27608819

Contralaterally Controlled Functional Electrical Stimulation Improves Hand Dexterity in Chronic Hemiparesis: A Randomized Trial.

PubMed

Knutson, Jayme S; Gunzler, Douglas D; Wilson, Richard D; Chae, John

2016-10-01

It is unknown whether one method of neuromuscular electrical stimulation for poststroke upper limb rehabilitation is more effective than another. Our aim was to compare the effects of contralaterally controlled functional electrical stimulation (CCFES) with cyclic neuromuscular electrical stimulation (cNMES). Stroke patients with chronic (>6 months) moderate to severe upper extremity hemiparesis (n=80) were randomized to receive 10 sessions/wk of CCFES- or cNMES-assisted hand opening exercise at home plus 20 sessions of functional task practice in the laboratory for 12 weeks. The task practice for the CCFES group was stimulation assisted. The primary outcome was change in Box and Block Test (BBT) score at 6 months post treatment. Upper extremity Fugl-Meyer and Arm Motor Abilities Test were also measured. At 6 months post treatment, the CCFES group had greater improvement on the BBT, 4.6 (95% confidence interval [CI], 2.2-7.0), than the cNMES group, 1.8 (95% CI, 0.6-3.0), between-group difference of 2.8 (95% CI, 0.1-5.5), P=0.045. No significant between-group difference was found for the upper extremity Fugl-Meyer (P=0.888) or Arm Motor Abilities Test (P=0.096). Participants who had the largest improvements on BBT were <2 years post stroke with moderate (ie, not severe) hand impairment at baseline. Among these, the 6-month post-treatment BBT gains of the CCFES group, 9.6 (95% CI, 5.6-13.6), were greater than those of the cNMES group, 4.1 (95% CI, 1.7-6.5), between-group difference of 5.5 (95% CI, 0.8-10.2), P=0.023. CCFES improved hand dexterity more than cNMES in chronic stroke survivors. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00891319. © 2016 American Heart Association, Inc.

A cochlear-bone wave can yield a hearing sensation as well as otoacoustic emission

PubMed Central

Tchumatchenko, Tatjana; Reichenbach, Tobias

2014-01-01

A hearing sensation arises when the elastic basilar membrane inside the cochlea vibrates. The basilar membrane is typically set into motion through airborne sound that displaces the middle ear and induces a pressure difference across the membrane. A second, alternative pathway exists, however: stimulation of the cochlear bone vibrates the basilar membrane as well. This pathway, referred to as bone conduction, is increasingly used in headphones that bypass the ear canal and the middle ear. Furthermore, otoacoustic emissions, sounds generated inside the cochlea and emitted therefrom, may not involve the usual wave on the basilar membrane, suggesting that additional cochlear structures are involved in their propagation. Here we describe a novel propagation mode within the cochlea that emerges through deformation of the cochlear bone. Through a mathematical and computational approach we demonstrate that this propagation mode can explain bone conduction as well as numerous properties of otoacoustic emissions. PMID:24954736

Tinnitus--Current Concepts in Diagnosis and Management.

ERIC Educational Resources Information Center

Epstein, Stephen

1997-01-01

This article discusses the causes of tinnitus, sound or noise in the ears or head without any external stimulation. Classification of tinnitus, the essentials of medical evaluation of a patient with tinnitus, essential test procedures, and current concepts in the management of tinnitus are addressed. (CR)

Application of the Vibrant Soundbridge in bilateral congenital atresia in toddlers.

PubMed

Frenzel, Henning; Hanke, Frauke; Beltrame, Millo; Wollenberg, Barbara

2010-08-01

The Vibrant Soundbridge offers an excellent audiologic rehabilitation for toddlers with microtia and atresia. It provides direct stimulation of the cochlea and straightforward adaption to the given anatomical structures. The 'posterior atresia incision' preserves the physical integrity of the tissue layers around the ear remnant, which is essential for an aesthetic auricular reconstruction. Patients with bilateral aural atresia require immediate auditory stimulation to ensure normal speech development. We present an operative technique that allows safe restoration of hearing before aesthetic reconstruction. A 6-year-old boy presented with bilateral microtia and osseous atresia. A hairline incision was performed through all layers and was followed by a subperiostal preparation towards the atresia plane. The fused malleus-incus-complex was removed and the transducer was crimped to the stapes suprastructure on both sides. Speech performance is nearly normal in both quiet and noise conditions. The surgery did not affect the tissues that are important for the later ear reconstruction.

Adipose-derived stromal cells enhance auditory neuron survival in an animal model of sensory hearing loss.

PubMed

Schendzielorz, Philipp; Vollmer, Maike; Rak, Kristen; Wiegner, Armin; Nada, Nashwa; Radeloff, Katrin; Hagen, Rudolf; Radeloff, Andreas

2017-10-01

A cochlear implant (CI) is an electronic prosthesis that can partially restore speech perception capabilities. Optimum information transfer from the cochlea to the central auditory system requires a proper functioning auditory nerve (AN) that is electrically stimulated by the device. In deafness, the lack of neurotrophic support, normally provided by the sensory cells of the inner ear, however, leads to gradual degeneration of auditory neurons with undesirable consequences for CI performance. We evaluated the potential of adipose-derived stromal cells (ASCs) that are known to produce neurotrophic factors to prevent neural degeneration in sensory hearing loss. For this, co-cultures of ASCs with auditory neurons have been studied, and autologous ASC transplantation has been performed in a guinea pig model of gentamicin-induced sensory hearing loss. In vitro ASCs were neuroprotective and considerably increased the neuritogenesis of auditory neurons. In vivo transplantation of ASCs into the scala tympani resulted in an enhanced survival of auditory neurons. Specifically, peripheral AN processes that are assumed to be the optimal activation site for CI stimulation and that are particularly vulnerable to hair cell loss showed a significantly higher survival rate in ASC-treated ears. ASC transplantation into the inner ear may restore neurotrophic support in sensory hearing loss and may help to improve CI performance by enhanced AN survival. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Differential Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones

NASA Astrophysics Data System (ADS)

Nakajima, Hideko Heidi; Dong, Wei; Olson, Elizabeth S.; Merchant, Saumil N.; Ravicz, Michael E.; Rosowski, John J.

2009-02-01

We present the first simultaneous sound pressure measurements in scala vestibuli and scala tympani of the cochlea in human cadaveric temporal bones. Micro-scale fiberoptic pressure sensors enabled the study of differential sound pressure at the cochlear base. This differential pressure is the input to the cochlear partition, driving cochlear waves and auditory transduction. Results showed that: pressure of scala vestibuli was much greater than scala tympani except at low and high frequencies where scala tympani pressure affects the input to the cochlea; the differential pressure proved to be an excellent measure of normal ossicular transduction of sound (shown to decrease 30-50 dB with ossicular disarticulation, whereas the individual scala pressures were significantly affected by non-ossicular conduction of sound at high frequencies); the middle-ear gain and differential pressure were generally bandpass in frequency dependence; and the middle-ear delay in the human was over twice that of the gerbil. Concurrent stapes velocity measurements allowed determination of the differential impedance across the partition and round-window impedance. The differential impedance was generally resistive, while the round-window impedance was consistent with a compliance in conjunction with distributed inertia and damping. Our techniques can be used to study inner-ear conductive pathologies (e.g., semicircular dehiscence), as well as non-ossicular cochlear stimulation (e.g., round-window stimulation) - situations that cannot be completely quantified by measurements of stapes velocity or scala-vestibuli pressure by themselves.

Nanosecond laser pulse stimulation of spiral ganglion neurons and model cells.

PubMed

Rettenmaier, Alexander; Lenarz, Thomas; Reuter, Günter

2014-04-01

Optical stimulation of the inner ear has recently attracted attention, suggesting a higher frequency resolution compared to electrical cochlear implants due to its high spatial stimulation selectivity. Although the feasibility of the effect is shown in multiple in vivo experiments, the stimulation mechanism remains open to discussion. Here we investigate in single-cell measurements the reaction of spiral ganglion neurons and model cells to irradiation with a nanosecond-pulsed laser beam over a broad wavelength range from 420 nm up to 1950 nm using the patch clamp technique. Cell reactions were wavelength- and pulse-energy-dependent but too small to elicit action potentials in the investigated spiral ganglion neurons. As the applied radiant exposure was much higher than the reported threshold for in vivo experiments in the same laser regime, we conclude that in a stimulation paradigm with nanosecond-pulses, direct neuronal stimulation is not the main cause of optical cochlea stimulation.

Utility of Otoacoustic Emissions and Olivocochlear Reflex in Predicting Vulnerability to Noise-Induced Inner Ear Damage

PubMed Central

Blioskas, Sarantis; Tsalighopoulos, Miltiadis; Psillas, George; Markou, Konstantinos

2018-01-01

Aim: The aim of the present study was to explore the possible utility of otoacoustic emissions (OAEs) and efferent system strength to determine vulnerability to noise exposure in a clinical setting. Materials and Methods: The study group comprised 344 volunteers who had just begun mandatory basic training as Hellenic Corps Officers Military Academy cadets. Pure-tone audiograms were obtained on both ears. Participants were also subjected to diagnostic transient-evoked otoacoustic emissions (TEOAEs). Finally, they were all tested for efferent function through the suppression of TEOAEs with contralateral noise. Following baseline evaluation, all cadets fired 10 rounds using a 7.62 mm Heckler & Koch G3A3 assault rifle while lying down in prone position. Immediately after exposure to gunfire noise and no later than 10 h, all participants completed an identical protocol for a second time, which was then repeated a third time, 30 days later. Results: The data showed that after the firing drill, 280 participants suffered a temporary threshold shift (TTS) (468 ears), while in the third evaluation conducted 30 days after exposure, 142 of these ears still presented a threshold shift compared to the baseline evaluation [permanent threshold shift (PTS) ears]. A receiver operating characteristics curve analysis showed that OAEs amplitude is predictive of future TTS and PTS. The results were slightly different for the suppression of OAEs showing only a slight trend toward significance. The curves were used to determine cut points to evaluate the likelihood of TTS/PTS for OAEs amplitude in the baseline evaluation. Decision limits yielding 71.6% sensitivity were 12.45 dB SPL with 63.8% specificity for PTS, and 50% sensitivity were 12.35 dB SPL with 68.2% specificity for TTS. Conclusions: Interestingly, the above data yielded tentative evidence to suggest that OAEs amplitude is both sensitive and specific enough to efficiently identify participants who are particularly susceptible to hearing loss caused by impulse noise generated by firearms. Hearing conservation programs may therefore want to consider including such tests in their routine. As far as efferent strength is concerned, we feel that further research is due, before implementing the suppression of OAEs in hearing conservations programs in a similar manner. PMID:29785975

Tympanometric findings in superior semicircular canal dehiscence syndrome.

PubMed

Castellucci, A; Brandolini, C; Piras, G; Modugno, G C

2013-04-01

The diagnostic role of audio-impedancemetry in superior semicircular canal dehiscence (SSCD) disease is well known. In particular, since the first reports, the presence of evoked acoustic reflexes has represented a determining instrumental exhibit in differential diagnosis with other middle ear pathologies that are responsible for a mild-low frequencies air-bone gap (ABG). Even though high resolution computed tomography (HRCT) completed by parasagittal reformatted images still represents the diagnostic gold standard, several instrumental tests can support a suspect of labyrinthine capsule dehiscence when "suggestive" symptoms occur. Objective and subjective audiometry often represents the starting point of the diagnostic course aimed at investigating the cause responsible for the so-called "intra-labyrinthine conductive hearing loss". The purpose of this study is to evaluate the role of tympanometry, in particular of the inter-aural asymmetry ratio in peak compliance as a function of different mild-low frequencies ABG on the affected side, in the diagnostic work-up in patients with unilateral SSCD. The working hypothesis is that an increase in admittance of the "inner-middle ear" conduction system due to a "third mobile window" could be detected by tympanometry. A retrospective review of the clinical records of 45 patients with unilateral dehiscence selected from a pool of 140 subjects diagnosed with SSCD at our institution from 2003 to 2011 was performed. Values of ABG amplitude on the dehiscent side and tympanometric measurements of both ears were collected for each patient in the study group (n = 45). An asymmetry between tympanometric peak compliance of the involved side and that of the contralateral side was investigated by calculating the inter-aural difference and the asymmetry ratio of compliance at the eardrum. A statistically significant correlation (p = 0.015 by Fisher's test) between an asymmetry ratio ≥ 14% in favour of the pathologic ear and an ABG > 20 dB nHL on the same side was found. When "evocative" symptoms of SSCD associated with important ABG occur, the inter-aural difference in tympanometric peak compliance at the eardrum in favour of the "suspected" side could suggest an intra-labyrinthine origin for the asymmetry. Tympanometry would thus prove to be a useful instrument in clinical-instrumental diagnosis of SSCD in detection of cases associated with alterations of inner ear impedance.

Stimulation of the substantia nigra influences the specification of memory-guided saccades

PubMed Central

Mahamed, Safraaz; Garrison, Tiffany J.; Shires, Joel

2013-01-01

In the absence of sensory information, we rely on past experience or memories to guide our actions. Because previous experimental and clinical reports implicate basal ganglia nuclei in the generation of movement in the absence of sensory stimuli, we ask here whether one output nucleus of the basal ganglia, the substantia nigra pars reticulata (nigra), influences the specification of an eye movement in the absence of sensory information to guide the movement. We manipulated the level of activity of neurons in the nigra by introducing electrical stimulation to the nigra at different time intervals while monkeys made saccades to different locations in two conditions: one in which the target location remained visible and a second in which the target location appeared only briefly, requiring information stored in memory to specify the movement. Electrical manipulation of the nigra occurring during the delay period of the task, when information about the target was maintained in memory, altered the direction and the occurrence of subsequent saccades. Stimulation during other intervals of the memory task or during the delay period of the visually guided saccade task had less effect on eye movements. On stimulated trials, and only when the visual stimulus was absent, monkeys occasionally (∼20% of the time) failed to make saccades. When monkeys made saccades in the absence of a visual stimulus, stimulation of the nigra resulted in a rotation of the endpoints ipsilaterally (∼2°) and increased the reaction time of contralaterally directed saccades. When the visual stimulus was present, stimulation of the nigra resulted in no significant rotation and decreased the reaction time of contralaterally directed saccades slightly. Based on these measurements, stimulation during the delay period of the memory-guided saccade task influenced the metrics of saccades much more than did stimulation during the same period of the visually guided saccade task. Because these effects occurred with manipulation of nigral activity well before the initiation of saccades and in trials in which the visual stimulus was absent, we conclude that information from the basal ganglia influences the specification of an action as it is evolving primarily during performance of memory-guided saccades. When visual information is available to guide the specification of the saccade, as occurs during visually guided saccades, basal ganglia information is less influential. PMID:24259551

Feasibility of spectral-domain phase-sensitive optical coherence tomography for middle ear vibrometry

PubMed Central

Nguyen-Huynh, Anh; Wang, Ruikang K.; Jacques, Steven L.; Choudhury, Niloy; Nuttall, Alfred L.

2012-01-01

Abstract. We describe a novel application of spectral-domain phase-sensitive optical coherence tomography (SD PS-OCT) to detect the tiny motions of the middle ear structures, such as the tympanic membrane and ossicular chain, and their morphological features for differential diagnosis of CHL. This technique has the potential to provide meaningful vibration of ossicles with a vibration sensitivity of ∼0.5  nm at 1 kHz of acoustic stimulation. To the best of our knowledge, this is the first demonstration of depth-resolved vibration imaging of ossicles with a PS-OCT system at a nanometer scale. PMID:22734728

Role of the middle ear muscle apparatus in mechanisms of speech signal discrimination

NASA Technical Reports Server (NTRS)

Moroz, B. S.; Bazarov, V. G.; Sachenko, S. V.

1980-01-01

A method of impedance reflexometry was used to examine 101 students with hearing impairment in order to clarify the interrelation between speech discrimination and the state of the middle ear muscles. Ability to discriminate speech signals depends to some extent on the functional state of intraaural muscles. Speech discrimination was greatly impaired in the absence of stapedial muscle acoustic reflex, in the presence of low thresholds of stimulation and in very small values of reflex amplitude increase. Discrimination was not impeded in positive AR, high values of relative thresholds and normal increase of reflex amplitude in response to speech signals with augmenting intensity.

Impact of coupling techniques of an active middle ear device to the round window membrane for the backward stimulation of the cochlea.

PubMed

Gostian, Antoniu-Oreste; Pazen, David; Ortmann, Magdalene; Luers, Jan-Christoffer; Anagiotos, Andreas; Hüttenbrink, Karl-Bernd; Beutner, Dirk

2015-01-01

Interposed cartilage and the round window coupler (RWC) increase the efficiency of cochlea stimulation with the floating mass transducer (FMT) of a single active middle ear implant (AMEI) placed against the round window membrane. Treatment of mixed and conductive hearing loss with an AMEI attached to the round window is effective, yet the best placement technique of its FMT for the most efficient stimulation of the cochlea remains to be determined. Experimental study on human temporal bones with the FMT placed against firstly the unaltered round window niche and then subsequently against the fully exposed round window membrane with and without interposed cartilage and the RWC. Cochlea stimulation is measured by the volume velocities of the stapes footplate using LASER vibrometry. At the undrilled round window niche, placement of the FMT by itself and with the RWC resulted in similar volume velocities. The response was significantly raised by interposing cartilage into the undrilled round window niche. Complete exposure of the round window membrane allowed for significantly increased volume velocities. Among these, coupling of the FMT with interposed cartilage yielded responses of similar magnitude compared with the RWC but significantly higher compared with the FMT by itself. Good contact to the round window membrane is essential for efficient stimulation of the cochlea. Therefore, interposing cartilage into the undrilled round window niche is a viable option. At the drilled round window membrane, the FMT with interposed cartilage and attached to the RWC are similarly effective.

The Relationship between MOC Reflex and Masked Threshold

PubMed Central

Garinis, Angela; Werner, Lynne; Abdala, Carolina

2011-01-01

Otoacoustic emission (OAE) amplitude can be reduced by acoustic stimulation. This effect is produced by the medial olivocochlear (MOC) reflex. Past studies have shown that the MOC reflex is related to listening in noise and attention. In the present study, the relationship between strength of the contralateral MOC reflex and masked threshold was investigated in 19 adults. Detection thresholds were determined for a 1000-Hz, 300-ms tone presented simultaneously with one repetition of a 300-ms masker in an ongoing train of 300-ms masker bursts at 600-ms intervals. Three masking conditions were tested: 1) broadband noise 2) a fixed-frequency 4-tone complex masker and 3) a random-frequency 4-tone complex masker. Broadband noise was expected to produce energetic masking and the tonal maskers were expected to produce informational masking in some listeners. DPOAEs were recorded at fine frequency interval from 500 to 4000 Hz, with and without contralateral acoustic stimulation. MOC reflex strength was estimated as a reduction in baseline level and a shift in frequency of DPOAE fine-structure maxima near 1000-Hz. MOC reflex and psychophysical testing were completed in separate sessions. Individuals with poorer thresholds in broadband noise and in random-frequency maskers were found to have stronger MOC reflexes. PMID:21878379

Neuroplasticity Changes on Human Motor Cortex Induced by Acupuncture Therapy: A Preliminary Study.

PubMed

Yang, Yi; Eisner, Ines; Chen, Siqi; Wang, Shaosong; Zhang, Fan; Wang, Linpeng

2017-01-01

While neuroplasticity changes measured by transcranial magnetic stimulation have been proved to be highly correlated to motor recovery and have been tested in various forms of interventions, it has not been applied to investigate the neurophysiologic mechanism of acupuncture therapy. The aim of this study is to investigate neuroplasticity changes induced by a single session of acupuncture therapy in healthy adults, regarding the excitability change on bilateral primary motor cortex and interhemispheric inhibition. Ten subjects took a 30-minute acupuncture therapy and the same length relaxing phase in separate days. Transcranial magnetic stimulation measures, including resting motor threshold, amplitudes of motor-evoked potential, and interhemispheric inhibition, were assessed before and 10 minutes after intervention. Acupuncture treatment showed significant changes on potential amplitude from both ipsilateral and contralateral hemispheres to acupuncture compared to baseline. Also, interhemispheric inhibition from the contralateral motor cortex to the opposite showed a significant decline. The results indicated that corticomotoneuronal excitability and interhemispheric competition could be modulated by acupuncture therapy on healthy subjects. The following question about whether these changes will be observed in the same way on stroke patients and whether they correlate with the therapeutic effect on movement need to be answered by following studies. This trial is registered with ISRCTN13074245.

Neuroplasticity Changes on Human Motor Cortex Induced by Acupuncture Therapy: A Preliminary Study

PubMed Central

Eisner, Ines; Chen, Siqi; Wang, Shaosong; Zhang, Fan

2017-01-01

While neuroplasticity changes measured by transcranial magnetic stimulation have been proved to be highly correlated to motor recovery and have been tested in various forms of interventions, it has not been applied to investigate the neurophysiologic mechanism of acupuncture therapy. The aim of this study is to investigate neuroplasticity changes induced by a single session of acupuncture therapy in healthy adults, regarding the excitability change on bilateral primary motor cortex and interhemispheric inhibition. Ten subjects took a 30-minute acupuncture therapy and the same length relaxing phase in separate days. Transcranial magnetic stimulation measures, including resting motor threshold, amplitudes of motor-evoked potential, and interhemispheric inhibition, were assessed before and 10 minutes after intervention. Acupuncture treatment showed significant changes on potential amplitude from both ipsilateral and contralateral hemispheres to acupuncture compared to baseline. Also, interhemispheric inhibition from the contralateral motor cortex to the opposite showed a significant decline. The results indicated that corticomotoneuronal excitability and interhemispheric competition could be modulated by acupuncture therapy on healthy subjects. The following question about whether these changes will be observed in the same way on stroke patients and whether they correlate with the therapeutic effect on movement need to be answered by following studies. This trial is registered with ISRCTN13074245. PMID:28293438

Non-ossicular signal transmission in human middle ears: Experimental assessment of the “acoustic route” with perforated tympanic membranes

PubMed Central

Voss, Susan E.; Rosowski, John J.; Merchant, Saumil N.; Peake, William T.

2008-01-01

Direct acoustic stimulation of the cochlea by the sound-pressure difference between the oval and round windows (called the “acoustic route”) has been thought to contribute to hearing in some pathological conditions, along with the normally dominant “ossicular route.” To determine the efficacy of this acoustic route and its constituent mechanisms in human ears, sound pressures were measured at three locations in cadaveric temporal bones [with intact and perforated tympanic membranes (TMs)]: (1) in the external ear canal lateral to the TM, PTM; (2) in the tympanic cavity lateral to the oval window, POW; and (3) near the round window, PRW. Sound transmission via the acoustic route is described by two concatenated processes: (1) coupling of sound pressure from ear canal to middle-ear cavity, HPCAV≡PCAV/PTM, where PCAV represents the middle-ear cavity pressure, and (2) sound-pressure difference between the windows, HWPD≡(POW−PRW)/PCAV. Results show that: HPCAV depends on perforation size but not perforation location; HWPD depends on neither perforation size nor location. The results (1) provide a description of the window pressures based on measurements, (2) refute the common otological view that TM perforation location affects the “relative phase of the pressures at the oval and round windows,” and (3) show with an intact ossicular chain that acoustic-route transmission is substantially below ossicular-route transmission except for low frequencies with large perforations. Thus, hearing loss from TM perforations results primarily from reduction in sound coupling via the ossicular route. Some features of the frequency dependence of HPCAV and HWPD can be interpreted in terms of a structure-based lumped-element acoustic model of the perforation and middle-ear cavities. PMID:17902851

Cortical activation with sound stimulation in cochlear implant users demonstrated by positron emission tomography.

PubMed

Naito, Y; Okazawa, H; Honjo, I; Hirano, S; Takahashi, H; Shiomi, Y; Hoji, W; Kawano, M; Ishizu, K; Yonekura, Y

1995-07-01

Six postlingually deaf patients using multi-channel cochlear implants were examined by positron emission tomography (PET) using 15O-labeled water. Changes in regional cerebral blood flow (rCBF) were measured during different sound stimuli. The stimulation paradigms employed consisted of two sets of three different conditions; (1) no sound stimulation with the speech processor of the cochlear implant system switched off, (2) hearing white noise and (3) hearing sequential Japanese sentences. In the primary auditory area, the mean rCBF increase during noise stimulation was significantly greater on the side contralateral to the implant than on the ipsilateral side. Speech stimulation caused significantly greater rCBF increase compared with noise stimulation in the left immediate auditory association area (P < 0.01), the bilateral auditory association areas (P < 0.01), the posterior part of the bilateral inferior frontal gyri; the Broca's area (P < 0.01) and its right hemisphere homologue (P < 0.05). Activation of cortices related to verbal and non-verbal sound recognition was clearly demonstrated in the current subjects probably because complete silence was attained in the control condition.

Vibrissa motor cortex activity suppresses contralateral whisking behavior.

PubMed

Ebbesen, Christian Laut; Doron, Guy; Lenschow, Constanze; Brecht, Michael

2017-01-01

Anatomical, stimulation and lesion data implicate vibrissa motor cortex in whisker motor control. Work on motor cortex has focused on movement generation, but correlations between vibrissa motor cortex activity and whisking are weak. The exact role of vibrissa motor cortex remains unknown. We recorded vibrissa motor cortex neurons during various forms of vibrissal touch, which were invariably associated with whisker protraction and movement. Free whisking, object palpation and social touch all resulted in decreased cortical activity. To understand this activity decrease, we performed juxtacellular recordings, nanostimulation and in vivo whole-cell recordings. Social touch resulted in decreased spiking activity, decreased cell excitability and membrane hyperpolarization. Activation of vibrissa motor cortex by intracortical microstimulation elicited whisker retraction, as if to abort vibrissal touch. Various vibrissa motor cortex inactivation protocols resulted in contralateral protraction and increased whisker movements. These data collectively point to movement suppression as a prime function of vibrissa motor cortex activity.

A New Analysis of Resting State Connectivity and Graph Theory Reveals Distinctive Short-Term Modulations due to Whisker Stimulation in Rats.

PubMed

Kreitz, Silke; de Celis Alonso, Benito; Uder, Michael; Hess, Andreas

2018-01-01

Resting state (RS) connectivity has been increasingly studied in healthy and diseased brains in humans and animals. This paper presents a new method to analyze RS data from fMRI that combines multiple seed correlation analysis with graph-theory (MSRA). We characterize and evaluate this new method in relation to two other graph-theoretical methods and ICA. The graph-theoretical methods calculate cross-correlations of regional average time-courses, one using seed regions of the same size (SRCC) and the other using whole brain structure regions (RCCA). We evaluated the reproducibility, power, and capacity of these methods to characterize short-term RS modulation to unilateral physiological whisker stimulation in rats. Graph-theoretical networks found with the MSRA approach were highly reproducible, and their communities showed large overlaps with ICA components. Additionally, MSRA was the only one of all tested methods that had the power to detect significant RS modulations induced by whisker stimulation that are controlled by family-wise error rate (FWE). Compared to the reduced resting state network connectivity during task performance, these modulations implied decreased connectivity strength in the bilateral sensorimotor and entorhinal cortex. Additionally, the contralateral ventromedial thalamus (part of the barrel field related lemniscal pathway) and the hypothalamus showed reduced connectivity. Enhanced connectivity was observed in the amygdala, especially the contralateral basolateral amygdala (involved in emotional learning processes). In conclusion, MSRA is a powerful analytical approach that can reliably detect tiny modulations of RS connectivity. It shows a great promise as a method for studying RS dynamics in healthy and pathological conditions.

A New Analysis of Resting State Connectivity and Graph Theory Reveals Distinctive Short-Term Modulations due to Whisker Stimulation in Rats

PubMed Central

Kreitz, Silke; de Celis Alonso, Benito; Uder, Michael; Hess, Andreas

2018-01-01

Resting state (RS) connectivity has been increasingly studied in healthy and diseased brains in humans and animals. This paper presents a new method to analyze RS data from fMRI that combines multiple seed correlation analysis with graph-theory (MSRA). We characterize and evaluate this new method in relation to two other graph-theoretical methods and ICA. The graph-theoretical methods calculate cross-correlations of regional average time-courses, one using seed regions of the same size (SRCC) and the other using whole brain structure regions (RCCA). We evaluated the reproducibility, power, and capacity of these methods to characterize short-term RS modulation to unilateral physiological whisker stimulation in rats. Graph-theoretical networks found with the MSRA approach were highly reproducible, and their communities showed large overlaps with ICA components. Additionally, MSRA was the only one of all tested methods that had the power to detect significant RS modulations induced by whisker stimulation that are controlled by family-wise error rate (FWE). Compared to the reduced resting state network connectivity during task performance, these modulations implied decreased connectivity strength in the bilateral sensorimotor and entorhinal cortex. Additionally, the contralateral ventromedial thalamus (part of the barrel field related lemniscal pathway) and the hypothalamus showed reduced connectivity. Enhanced connectivity was observed in the amygdala, especially the contralateral basolateral amygdala (involved in emotional learning processes). In conclusion, MSRA is a powerful analytical approach that can reliably detect tiny modulations of RS connectivity. It shows a great promise as a method for studying RS dynamics in healthy and pathological conditions. PMID:29875622

Longitudinal endolymph movements and endocochlear potential changes induced by stimulation at infrasonic frequencies.

PubMed

Salt, A N; DeMott, J E

1999-08-01

The inner ear is continually exposed to pressure fluctuations in the infrasonic frequency range (< 20 Hz) from external and internal body sources. The cochlea is generally regarded to be insensitive to such stimulation. The effects of stimulation at infrasonic frequencies (0.1 to 10 Hz) on endocochlear potential (EP) and endolymph movements in the guinea pig cochlea were studied. Stimuli were applied directly to the perilymph of scala tympani or scala vestibuli of the cochlea via a fluid-filled pipette. Stimuli, especially those near 1 Hz, elicited large EP changes which under some conditions exceeded 20 mV in amplitude and were equivalent to a cochlear microphonic (CM) response. Accompanying the electrical responses was a cyclical, longitudinal displacement of the endolymph. The amplitude and phase of the CM varied according to which perilymphatic scala the stimuli were applied to and whether a perforation was made in the opposing perilymphatic scala. Spontaneously occurring middle ear muscle contractions were also found to induce EP deflections and longitudinal endolymph movements comparable to those generated by perilymphatic injections. These findings suggest that cochlear fluid movements induced by pressure fluctuations at infrasonic frequencies could play a role in fluid homeostasis in the normal state and in fluid disturbances in pathological states.

Green laser light activates the inner ear

NASA Astrophysics Data System (ADS)

Wenzel, Gentiana I.; Balster, Sven; Zhang, Kaiyin; Lim, Hubert H.; Reich, Uta; Massow, Ole; Lubatschowski, Holger; Ertmer, Wolfgang; Lenarz, Thomas; Reuter, Guenter

2009-07-01

The hearing performance with conventional hearing aids and cochlear implants is dramatically reduced in noisy environments and for sounds more complex than speech (e. g. music), partially due to the lack of localized sensorineural activation across different frequency regions with these devices. Laser light can be focused in a controlled manner and may provide more localized activation of the inner ear, the cochlea. We sought to assess whether visible light with parameters that could induce an optoacoustic effect (532 nm, 10-ns pulses) would activate the cochlea. Auditory brainstem responses (ABRs) were recorded preoperatively in anesthetized guinea pigs to confirm normal hearing. After opening the bulla, a 50-μm core-diameter optical fiber was positioned in the round window niche and directed toward the basilar membrane. Optically induced ABRs (OABRs), similar in shape to those of acoustic stimulation, were elicited with single pulses. The OABR peaks increased with energy level (0.6 to 23 μJ/pulse) and remained consistent even after 30 minutes of continuous stimulation at 13 μJ, indicating minimal or no stimulation-induced damage within the cochlea. Our findings demonstrate that visible light can effectively and reliably activate the cochlea without any apparent damage. Further studies are in progress to investigate the frequency-specific nature and mechanism of green light cochlear activation.

Integrating temperature with odor processing in the olfactory bulb.

PubMed

Kludt, Eugen; Okom, Camille; Brinkmann, Alexander; Schild, Detlev

2015-05-20

Temperature perception has long been classified as a somesthetic function solely. However, in recent years several studies brought evidence that temperature perception also takes place in the olfactory system of rodents. Temperature has been described as an effective stimulus for sensory neurons of the Grueneberg ganglion located at the entrance of the nose. Here, we investigate whether a neuronal trace of temperature stimulation can be observed in the glomeruli and mitral cells of the olfactory bulb, using calcium imaging and fast line-scanning microscopy. We show in the Xenopus tadpole system that the γ-glomerulus, which receives input from olfactory neurons, is highly sensitive to temperature drops at the olfactory epithelium. We observed that thermo-induced activity in the γ-glomerulus is conveyed to the mitral cells innervating this specific neuropil. Surprisingly, a substantial number of thermosensitive mitral cells were also chemosensitive. Moreover, we report another unique feature of the γ-glomerulus: it receives ipsilateral and contralateral afferents. The latter fibers pass through the contralateral bulb, cross the anterior commissure, and then run to the ipsilateral olfactory bulb, where they target the γ-glomerulus. Temperature drops at the contralateral olfactory epithelium also induced responses in the γ-glomerulus and in mitral cells. Temperature thus appears to be a relevant physiological input to the Xenopus olfactory system. Each olfactory bulb integrates and codes temperature signals originating from receptor neurons of the ipsilateral and contralateral nasal cavities. Finally, temperature and chemical information is processed in shared cellular networks. Copyright © 2015 the authors 0270-6474/15/357892-11$15.00/0.

The Mirror Illusion Increases Motor Cortex Excitability in Children With and Without Hemiparesis.

PubMed

Grunt, Sebastian; Newman, Christopher J; Saxer, Stefanie; Steinlin, Maja; Weisstanner, Christian; Kaelin-Lang, Alain

2017-03-01

Mirror therapy provides a visual illusion of a normal moving limb by using the mirror reflection of the unaffected arm instead of viewing the paretic limb and is used in rehabilitation to improve hand function. Little is known about the mechanism underlying its effect in children with hemiparesis. To investigate the effect of the mirror illusion (MI) on the excitability of the primary motor cortex (M1) in children and adolescents. Twelve patients with hemiparesis (10-20 years) and 8 typically developing subjects (8-17 years) participated. Corticospinal reorganization was classified as contralateral (projection from contralateral hemisphere to affected hand) or ipsilateral (projection from ipsilateral hemisphere to affected hand). M1 excitability of the hemisphere projecting to the affected (nondominant in typically developing subjects) hand was obtained during 2 different conditions using single-pulse transcranial magnetic stimulation (TMS). Each condition (without/with mirror) consisted of a unimanual and a bimanual task. Motor-evoked potentials (MEPs) were recorded from the abductor pollicis brevis and flexor digitorum superficialis muscles. MEP amplitudes were significantly increased during the mirror condition ( P = .005) in typically developing subjects and in patients with contralateral reorganization. No significant effect of MI was found in subjects with ipsilateral reorganization. MI increased M1 excitability during active movements only. This increase was not correlated to hand function. MI increases the excitability of M1 in hemiparetic patients with contralateral corticospinal organization and in typically developing subjects. This finding provides neurophysiological evidence supporting the application of mirror therapy in selected children and adolescents with hemiparesis.

Ocular vestibular evoked myogenic potentials to vertex low frequency vibration as a diagnostic test for superior canal dehiscence.

PubMed

Verrecchia, Luca; Westin, Magnus; Duan, Maoli; Brantberg, Krister

2016-04-01

To explore ocular vestibular evoked myogenic potentials (oVEMP) to low-frequency vertex vibration (125 Hz) as a diagnostic test for superior canal dehiscence (SCD) syndrome. The oVEMP using 125 Hz single cycle bone-conducted vertex vibration were tested in 15 patients with unilateral superior canal dehiscence (SCD) syndrome, 15 healthy controls and in 20 patients with unilateral vestibular loss due to vestibular neuritis. Amplitude, amplitude asymmetry ratio, latency and interaural latency difference were parameters of interest. The oVEMP amplitude was significantly larger in SCD patients when affected sides (53 μVolts) were compared to non-affected (17.2 μVolts) or compared to healthy controls (13.6 μVolts). Amplitude larger than 33.8 μVolts separates effectively the SCD ears from the healthy ones with sensitivity of 87% and specificity of 93%. The other three parameters showed an overlap between affected SCD ears and non-affected as well as between SCD ears and those in the two control groups. oVEMP amplitude distinguishes SCD ears from healthy ones using low-frequency vibration stimuli at vertex. Amplitude analysis of oVEMP evoked by low-frequency vertex bone vibration stimulation is an additional indicator of SCD syndrome and might serve for diagnosing SCD patients with coexistent conductive middle ear problems. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Topical atorvastatin ameliorates 12-O-tetradecanoylphorbol-13-acetate induced skin inflammation by reducing cutaneous cytokine levels and NF-κB activation.

PubMed

Kulkarni, Nagaraj M; Muley, Milind M; Jaji, Mallikarjun S; Vijaykanth, G; Raghul, J; Reddy, Neetin Kumar D; Vishwakarma, Santosh L; Rajesh, Navin B; Mookkan, Jeyamurugan; Krishnan, Uma Maheswari; Narayanan, Shridhar

2015-06-01

Atorvastatin is a 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitor used in the treatment of atherosclerosis and dyslipidemia. Studies have evaluated the utility of statins in the treatment of skin inflammation but with varied results. In the present study, we investigated the effect of atorvastatin on TNF-α release and keratinocyte proliferation in vitro and in acute and chronic 12-O-tetradecanoylphorbol-13-acetate (TPA) induced skin inflammation in vivo. Atorvastatin significantly inhibited lipopolysacharide induced TNF-α release in THP-1 cells and keratinocyte proliferation in HaCaT cells. In an acute study, topical atorvastatin showed dose dependent reduction in TPA induced skin inflammation with highest efficacy observed at 500 µg/ear dose. In chronic study, topical atorvastatin significantly reduced TPA induced ear thickness, ear weight, cutaneous cytokines, MPO activity and improved histopathological features comparable to that of dexamethasone. Atorvastatin also inhibited TPA stimulated NF-κB activation in mouse ear. In conclusion, our results suggest that atorvastatin ameliorates TPA induced skin inflammation in mice at least in part, due to inhibition of cytokine release and NF-κB activation and may be beneficial for the treatment skin inflammation like psoriasis.

Correlation between blink reflex abnormalities and magnetic resonance imaging findings in patients with multiple sclerosis.

PubMed

Degirmenci, Eylem; Erdogan, Cagdas; Bir, Levent Sinan

2013-09-01

This study investigates the correlation between brain magnetic resonance imaging findings and blink reflex abnormalities in patients with relapsing remitting multiple sclerosis. Twenty-six patients and 17 healthy subjects were included in this study. Blink reflex test (BRT) results were obtained using right and left stimulations; thus, 52 BRT results were recorded for the patient group, and 34 BRT results were recorded for the control group. The magnetic resonance imaging (MRI) findings were classified based on the existence of brainstem lesions (hyperintense lesion on T2 weighted (W) and fast fluid-attenuated inversion recovery MRI or contrast-enhancing lesion on T1W MRI). Correlation analysis was performed for the BRT and MRI findings. The percentage of individuals with abnormal BRT results (including R1 latency, ipsilateral R2 latency, and contralateral R2 latency) was significantly higher in the patient group as compared to the control group (p values: 0.015, 0.001, and 0.002, respectively). Correlation analysis revealed significant correlations between contralateral R2 latency abnormalities and brainstem lesions (p value: 0.011). Our results showed significant correlation correlations between contralateral R2 latency abnormalities and brainstem lesions and these results may be explained the effects of multiple demyelinating lesions of the brain stem of patients with relapsing remitting multiple sclerosis.

Localization by interaural time difference (ITD): Effects of interaural frequency mismatch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonham, B.H.; Lewis, E.R.

1999-07-01

A commonly accepted physiological model for lateralization of low-frequency sounds by interaural time delay (ITD) stipulates that binaural comparison neurons receive input from frequency-matched channels from each ear. Here, the effects of hypothetical interaural frequency mismatches on this model are reported. For this study, the cat{close_quote}s auditory system peripheral to the binaural comparison neurons was represented by a neurophysiologically derived model, and binaural comparison neurons were represented by cross-correlators. The results of the study indicate that, for binaural comparison neurons receiving input from one cochlear channel from each ear, interaural CF mismatches may serve to either augment or diminish themore » effective difference in ipsilateral and contralateral axonal time delays from the periphery to the binaural comparison neuron. The magnitude of this increase or decrease in the effective time delay difference can be up to 400 {mu}s for CF mismatches of 0.2 octaves or less for binaural neurons with CFs between 250 Hz and 2.5 kHz. For binaural comparison neurons with nominal CFs near 500 Hz, the 25-{mu}s effective time delay difference caused by a 0.012-octave CF mismatch is equal to the ITD previously shown to be behaviorally sufficient for the cat to lateralize a low-frequency sound source. {copyright} {ital 1999 Acoustical Society of America.}« less

[Intratympanic injection therapy for therapy refractory acute hearing loss: A safe option for secondary treatment].

PubMed

Mühlmeier, G; Maier, S; Maier, M; Maier, H

2015-10-01

High-dose corticosteroids are currently recommended for idiopathic sudden sensorineural hearing loss (ISSNHL) treatment. Intratympanic injections (ITI) are of growing importance, especially in cases of therapy resistance. The selection of patients for this procedure in SSNHL has not been adequately examined so far. A total of 77 patients with ISSNHL after ineffective systemic pretreatment underwent intratympanic administration of dexamethasone and hyaluronic acid. Improvement after treatment was determined by pure tone audiometry for both ears before and of the treated ear after ITI. In this study 34 female and 43 male patients with mean age of 57 years showed a pre-ITI hearing loss of 35 dB in the lower frequencies and 69 dB in the higher frequencies. The mean hearing gain was 10 dB and the response rate was 62%. Absolute hearing gain revealed significant improvements at 500 Hz, 1 kHz and 2 kHz. Under inclusion of contralateral thresholds there were hardly any differences up to 4 kHz. In a detailed analysis of responders moderate improvements could be observed even in higher frequencies. Overall, no relevant adverse events occurred. Treatment of ISSNHL resistant to systemic regimens by ITI of steroids provides an option that offers additional prospects of auditory improvement for affected patients. The presented results indicate that these modalities are also valid for patients with pancochlear ISSNHL.

Cranial pneumatization and auditory perceptions of the oviraptorid dinosaur Conchoraptor gracilis (Theropoda, Maniraptora) from the Late Cretaceous of Mongolia

NASA Astrophysics Data System (ADS)

Ramanah, D.; Raghunath, S.; Mee, D. J.; Rösgen, T.; Jacobs, P. A.

2007-09-01

The distribution of air-filled structures in the craniofacial and neurocranial bones of the oviraptorid ZPAL MgD-I/95, discovered at the Hermiin Tsav locality, Mongolia, is restored. Based on the complete obliteration of most of the cranial sutures, the specimen is identified as an adult individual of Conchoraptor gracilis Barsbold 1986. Except for the orbitosphenoids and epipterygoids, the preserved bones of the neurocranium are hollow. Three types of tympanic recess are present in Conchoraptor, a characteristic shared with troodontids, dromaeosaurids, and avian theropods. The contralateral middle ear cavities are interconnected by the supraencephalic pathway that passes through the dorsal tympanic recesses, the posterodorsal prootic sinuses and the parietal sinus. The spatial arrangements of the middle ear cavity and a derived neurocranial pneumatic system in Conchoraptor indicate enhancements of acoustic perception in the lower-frequency registers and of auditory directionality. We further speculate that this improvement of binaural hearing could be explained as an adaptation required for accurate detection of prey and/or predators under conditions of low illumination. The other potentially pneumatic structures of the Conchoraptor cranium include (1) recessus-like irregularities on the dorsal surface of the nasal and frontal bones (a putative oviraptorid synapomorphy; pos); (2) a subotic recess; (3) a sub-condylar recess; and (4) a posterior condylar recess (pos).

Effects of smoking marijuana on focal attention and brain blood flow.

PubMed

O'Leary, Daniel S; Block, Robert I; Koeppel, Julie A; Schultz, Susan K; Magnotta, Vincent A; Ponto, Laura Boles; Watkins, G Leonard; Hichwa, Richard D

2007-04-01

Using an attention task to control cognitive state, we previously found that smoking marijuana changes regional cerebral blood flow (rCBF). The present study measured rCBF during tasks requiring attention to left and right ears in different conditions. Twelve occasional marijuana users (mean age 23.5 years) were imaged with PET using [15O]water after smoking marijuana or placebo cigarettes as they performed a reaction time (RT) baseline task, and a dichotic listening task with attend-right- and attend-left-ear instructions. Smoking marijuana, but not placebo, resulted in increased normalized rCBF in orbital frontal cortex, anterior cingulate, temporal pole, insula, and cerebellum. RCBF was reduced in visual and auditory cortices. These changes occurred in all three tasks and replicated our earlier studies. They appear to reflect the direct effects of marijuana on the brain. Smoking marijuana lowered rCBF in auditory cortices compared to placebo but did not alter the normal pattern of attention-related rCBF asymmetry (i.e., greater rCBF in the temporal lobe contralateral to the direction of attention) that was also observed after placebo. These data indicate that marijuana has dramatic direct effects on rCBF, but causes relatively little change in the normal pattern of task-related rCBF on this auditory focused attention task. Copyright 2007 John Wiley & Sons, Ltd.

Bone conduction responses of middle ear structures in Thiel embalmed heads

NASA Astrophysics Data System (ADS)

Arnold, Andreas; Stieger, Christof; Caversaccio, Marco; Kompis, Martin; Guignard, Jérémie

2015-12-01

Thiel-embalmed human whole-head specimens offer a promising alternative model for bone conduction (BC) studies of middle ear structures. In this work we present the Thiel model's linearity and stability over time as well as its possible use in the study of a fixed ossicle chain. Using laser Doppler vibrometry (LDV), the motion of the retroauricular skull, the promontory, the stapes footplate and the round window (RW) were measured. A bone-anchored hearing aid stimulated the ears with step sinus tones logarithmically spread between 0.1 and 10 kHz. Linearity of the model was verified using input levels in steps of 10 dBV. The stability of the Thiel model over time was examined with measurements repeated after hours and weeks. The influence of a cement-fixed stapes was assessed. The middle ear elements measured responded linearly in amplitude for the applied input levels (100, 32.6, and 10 mV). The variability of measurements for both short- (2 h) and long-term (4-16 weeks) repetitions in the same ear was lower than the interindividual difference. The fixation of the stapes induced a lowered RW displacement for frequencies near 750 Hz (-4 dB) and an increased displacement for frequencies above 1 kHz (max. +3.7 dB at 4 kHz). LDV assessment of BC-induced middle ear motion in Thiel heads can be performed with stable results. The vibratory RW response is affected by the fixation of the stapes, indicating a measurable effect of ossicle chain inertia on BC response in Thiel embalmed heads.

Effects of Hearing Preservation on Psychophysical Responses to Cochlear Implant Stimulation

PubMed Central

Kang, Stephen Y.; Colesa, Deborah J.; Swiderski, Donald L.; Su, Gina L.; Raphael, Yehoash

2009-01-01

Previous studies have shown that residual acoustic hearing supplements cochlear implant function to improve speech recognition in noise as well as perception of music. The current study had two primary objectives. First, we sought to determine how cochlear implantation and electrical stimulation over a time period of 14 to 21 months influence cochlear structures such as hair cells and spiral ganglion neurons. Second, we sought to investigate whether the structures that provide acoustic hearing also affect the perception of electrical stimulation. We compared psychophysical responses to cochlear implant stimulation in two groups of adult guinea pigs. Group I (11 animals) received a cochlear implant in a previously untreated ear, while group II (ten animals) received a cochlear implant in an ear that had been previously infused with neomycin to destroy hearing. Psychophysical thresholds were measured in response to pulse-train and sinusoidal stimuli. Histological analysis of all group I animals and a subset of group II animals was performed. Nine of the 11 group I animals showed survival of the organ of Corti and spiral ganglion neurons adjacent to the electrode array. All group I animals showed survival of these elements in regions apical to the electrode array. Group II animals that were examined histologically showed complete loss of the organ of Corti in regions adjacent and apical to the electrode array and severe spiral ganglion neuron loss, consistent with previous reports for neomycin-treated ears. Behaviorally, group II animals had significantly lower thresholds than group I animals in response to 100 Hz sinusoidal stimuli. However, group I animals had significantly lower thresholds than group II animals in response to pulse-train stimuli (0.02 ms/phase; 156 to 5,000 pps). Additionally, the two groups showed distinct threshold versus pulse rate functions. We hypothesize that the differences in detection thresholds between groups are caused by the electrical activation of the hair cells in group I animals and/or differences between groups in the condition of the spiral ganglion neurons. PMID:19902297

Neuronal activity related to spontaneous and capsaicin-induced rhythmical jaw movements in the rat.

PubMed

Ohta, M; Sasamoto, K; Kobayashi, J

1998-02-01

Intraoral capsaicin induced rhythmical jaw movements (RJM) in anesthetized rats. Neurons in the trigeminal spinal nucleus caudalis or the cortico-peduncular (CP) axons were extracellularly recorded. Capsaicin excited dose-dependently most caudalis neurons, which were activated by stimulation of the oral cavity and/or the tooth pulp and activated during spontaneous or induced RJM. Ten of 55 CP axons were antidromically activated by stimulation of the contralateral trigeminal motor nucleus. All antidromic and 29 other CP axons discharged prior to the spontaneous RJM, but most of them did not during capsaicin-induced RJM. These neuronal activities possibly initiate spontaneous RJM although the activities of caudalis neurons are necessary for capsicin-induced RJM.

Connectivity derived thalamic segmentation in deep brain stimulation for tremor.

PubMed

Akram, Harith; Dayal, Viswas; Mahlknecht, Philipp; Georgiev, Dejan; Hyam, Jonathan; Foltynie, Thomas; Limousin, Patricia; De Vita, Enrico; Jahanshahi, Marjan; Ashburner, John; Behrens, Tim; Hariz, Marwan; Zrinzo, Ludvic

2018-01-01

The ventral intermediate nucleus (VIM) of the thalamus is an established surgical target for stereotactic ablation and deep brain stimulation (DBS) in the treatment of tremor in Parkinson's disease (PD) and essential tremor (ET). It is centrally placed on a cerebello-thalamo-cortical network connecting the primary motor cortex, to the dentate nucleus of the contralateral cerebellum through the dentato-rubro-thalamic tract (DRT). The VIM is not readily visible on conventional MR imaging, so identifying the surgical target traditionally involved indirect targeting that relies on atlas-defined coordinates. Unfortunately, this approach does not fully account for individual variability and requires surgery to be performed with the patient awake to allow for intraoperative targeting confirmation. The aim of this study is to identify the VIM and the DRT using probabilistic tractography in patients that will undergo thalamic DBS for tremor. Four male patients with tremor dominant PD and five patients (three female) with ET underwent high angular resolution diffusion imaging (HARDI) (128 diffusion directions, 1.5 mm isotropic voxels and b value = 1500) preoperatively. Patients received VIM-DBS using an MR image guided and MR image verified approach with indirect targeting. Postoperatively, using parallel Graphical Processing Unit (GPU) processing, thalamic areas with the highest diffusion connectivity to the primary motor area (M1), supplementary motor area (SMA), primary sensory area (S1) and contralateral dentate nucleus were identified. Additionally, volume of tissue activation (VTA) corresponding to active DBS contacts were modelled. Response to treatment was defined as 40% reduction in the total Fahn-Tolosa-Martin Tremor Rating Score (FTMTRS) with DBS-ON, one year from surgery. Three out of nine patients had a suboptimal, long-term response to treatment. The segmented thalamic areas corresponded well to anatomically known counterparts in the ventrolateral (VL) and ventroposterior (VP) thalamus. The dentate-thalamic area, lay within the M1-thalamic area in a ventral and lateral location. Streamlines corresponding to the DRT connected M1 to the contralateral dentate nucleus via the dentate-thalamic area, clearly crossing the midline in the mesencephalon. Good response was seen when the active contact VTA was in the thalamic area with highest connectivity to the contralateral dentate nucleus. Non-responders had active contact VTAs outside the dentate-thalamic area. We conclude that probabilistic tractography techniques can be used to segment the VL and VP thalamus based on cortical and cerebellar connectivity. The thalamic area, best representing the VIM, is connected to the contralateral dentate cerebellar nucleus. Connectivity based segmentation of the VIM can be achieved in individual patients in a clinically feasible timescale, using HARDI and high performance computing with parallel GPU processing. This same technique can map out the DRT tract with clear mesencephalic crossing.

Non-Invasive Electrical Brain Stimulation Montages for Modulation of Human Motor Function.

PubMed

Curado, Marco; Fritsch, Brita; Reis, Janine

2016-02-04

Non-invasive electrical brain stimulation (NEBS) is used to modulate brain function and behavior, both for research and clinical purposes. In particular, NEBS can be applied transcranially either as direct current stimulation (tDCS) or alternating current stimulation (tACS). These stimulation types exert time-, dose- and in the case of tDCS polarity-specific effects on motor function and skill learning in healthy subjects. Lately, tDCS has been used to augment the therapy of motor disabilities in patients with stroke or movement disorders. This article provides a step-by-step protocol for targeting the primary motor cortex with tDCS and transcranial random noise stimulation (tRNS), a specific form of tACS using an electrical current applied randomly within a pre-defined frequency range. The setup of two different stimulation montages is explained. In both montages the emitting electrode (the anode for tDCS) is placed on the primary motor cortex of interest. For unilateral motor cortex stimulation the receiving electrode is placed on the contralateral forehead while for bilateral motor cortex stimulation the receiving electrode is placed on the opposite primary motor cortex. The advantages and disadvantages of each montage for the modulation of cortical excitability and motor function including learning are discussed, as well as safety, tolerability and blinding aspects.

Interaural time discrimination of envelopes carried on high-frequency tones as a function of level and interaural carrier mismatch

PubMed Central

Blanks, Deidra A.; Buss, Emily; Grose, John H.; Fitzpatrick, Douglas C.; Hall, Joseph W.

2009-01-01

Objectives The present study investigated interaural time discrimination for binaurally mismatched carrier frequencies in listeners with normal hearing. One goal of the investigation was to gain insights into binaural hearing in patients with bilateral cochlear implants, where the coding of interaural time differences may be limited by mismatches in the neural populations receiving stimulation on each side. Design Temporal envelopes were manipulated to present low frequency timing cues to high frequency auditory channels. Carrier frequencies near 4 kHz were amplitude modulated at 128 Hz via multiplication with a half-wave rectified sinusoid, and that modulation was either in-phase across ears or delayed to one ear. Detection thresholds for non-zero interaural time differences were measured for a range of stimulus levels and a range of carrier frequency mismatches. Data were also collected under conditions designed to limit cues based on stimulus spectral spread, including masking and truncation of sidebands associated with modulation. Results Listeners with normal hearing can detect interaural time differences in the face of substantial mismatches in carrier frequency across ears. Conclusions The processing of interaural time differences in listeners with normal hearing is likely based on spread of excitation into binaurally matched auditory channels. Sensitivity to interaural time differences in listeners with cochlear implants may depend upon spread of current that results in the stimulation of neural populations that share common tonotopic space bilaterally. PMID:18596646

Living in a ``stethoscope'': burrow-acoustics promote auditory specializations in subterranean rodents

NASA Astrophysics Data System (ADS)

Lange, Simone; Burda, Hynek; Wegner, Regina E.; Dammann, Philip; Begall, Sabine; Kawalika, Mathias

2007-02-01

Subterranean mammals rely to a great extent on audition for communication and to be alerted to danger. The only hitherto published report on burrow acoustics revealed that in tunnels of blind mole-rats ( Spalax ehrenbergi), airborne sounds of 440 Hz propagated best whereas lower and higher frequencies were effectively attenuated. Morpho-functional analyses classify the ear of subterranean mammals as a low-sensitivity and low-frequency device. Concordantly, hearing is characterized by low sensitivity and a restricted frequency range tuned to low frequencies (0.5-4 kHz). Some authors considered the restricted hearing in subterranean mammals vestigial and degenerate due to under-stimulation. In contrast to this view stand a rich (mostly low-frequency) vocal repertoire and progressive structural specializations of the middle and inner ear. Thus, other authors considered these hearing characteristics adaptive. To test the hypothesis that acoustical environment in burrows of different species of subterranean mammals is similar, we measured sound attenuation in burrows of Fukomys mole-rats (formerly known as Cryptomys, cf. Kock et al. 2006) of two differently sized species at different locations in Zambia. We show that in these burrows, low-frequency sounds (200-800 Hz) are not only least attenuated but also their amplitude may be amplified like in a stethoscope (up to two times over 1 m). We suggest that hearing sensitivity has decreased during evolution of subterranean mammals to avoid over-stimulation of the ear in their natural environment.

Speech auditory brainstem response (speech ABR) characteristics depending on recording conditions, and hearing status: an experimental parametric study.

PubMed

Akhoun, Idrick; Moulin, Annie; Jeanvoine, Arnaud; Ménard, Mikael; Buret, François; Vollaire, Christian; Scorretti, Riccardo; Veuillet, Evelyne; Berger-Vachon, Christian; Collet, Lionel; Thai-Van, Hung

2008-11-15

Speech elicited auditory brainstem responses (Speech ABR) have been shown to be an objective measurement of speech processing in the brainstem. Given the simultaneous stimulation and recording, and the similarities between the recording and the speech stimulus envelope, there is a great risk of artefactual recordings. This study sought to systematically investigate the source of artefactual contamination in Speech ABR response. In a first part, we measured the sound level thresholds over which artefactual responses were obtained, for different types of transducers and experimental setup parameters. A watermelon model was used to model the human head susceptibility to electromagnetic artefact. It was found that impedances between the electrodes had a great effect on electromagnetic susceptibility and that the most prominent artefact is due to the transducer's electromagnetic leakage. The only artefact-free condition was obtained with insert-earphones shielded in a Faraday cage linked to common ground. In a second part of the study, using the previously defined artefact-free condition, we recorded speech ABR in unilateral deaf subjects and bilateral normal hearing subjects. In an additional control condition, Speech ABR was recorded with the insert-earphones used to deliver the stimulation, unplugged from the ears, so that the subjects did not perceive the stimulus. No responses were obtained from the deaf ear of unilaterally hearing impaired subjects, nor in the insert-out-of-the-ear condition in all the subjects, showing that Speech ABR reflects the functioning of the auditory pathways.

Effects of laterality and pitch height of an auditory accessory stimulus on horizontal response selection: the Simon effect and the SMARC effect.

PubMed

Nishimura, Akio; Yokosawa, Kazuhiko

2009-08-01

In the present article, we investigated the effects of pitch height and the presented ear (laterality) of an auditory stimulus, irrelevant to the ongoing visual task, on horizontal response selection. Performance was better when the response and the stimulated ear spatially corresponded (Simon effect), and when the spatial-musical association of response codes (SMARC) correspondence was maintained-that is, right (left) response with a high-pitched (low-pitched) tone. These findings reveal an automatic activation of spatially and musically associated responses by task-irrelevant auditory accessory stimuli. Pitch height is strong enough to influence the horizontal responses despite modality differences with task target.

Stimulation from Cochlear Implant Electrodes Assists with Recovery from Asymmetric Perceptual Tilt: Evidence from the Subjective Visual Vertical Test

PubMed Central

Gnanasegaram, Joshua J.; Parkes, William J.; Cushing, Sharon L.; McKnight, Carmen L.; Papsin, Blake C.; Gordon, Karen A.

2016-01-01

Vestibular end organ impairment is highly prevalent in children who have sensorineural hearing loss (SNHL) rehabilitated with cochlear implants (CIs). As a result, spatial perception is likely to be impacted in this population. Of particular interest is the perception of visual vertical because it reflects a perceptual tilt in the roll axis and is sensitive to an imbalance in otolith function. The objectives of the present study were thus to identify abnormalities in perception of the vertical plane in children with SNHL and determine whether such abnormalities could be resolved with stimulation from the CI. Participants included 53 children (15.2 ± 4.0 years of age) with SNHL and vestibular loss, confirmed with vestibular evoked myogenic potential (VEMP) testing. Testing protocol was validated in a sample of nine young adults with normal hearing (28.8 ± 7.7 years). Perception of visual vertical was assessed using the static Subjective Visual Vertical (SVV) test performed with and without stimulation in the participants with cochleovestibular loss. Trains of electrical pulses were delivered by an electrode in the left and/or right ear. Asymmetric spatial orientation deficits were found in nearly half of the participants with CIs (24/53 [45%]). The abnormal perception in this cohort was exacerbated by visual tilts in the direction of their deficit. Electric pulse trains delivered using the CI shifted this abnormal perception towards center (i.e., normal; p = 0.007). Importantly, this benefit was realized regardless of which ear was stimulated. These results suggest a role for CI stimulation beyond the auditory system, in particular, for improving vestibular/balance function. PMID:27679562

Synovex Plus implants coated with a polymeric, porous film improve performance of beef steers and heifers fed in confinement for up to 200 days.

PubMed

Cleale, R M; Bechtol, D T; Drouillard, J S; Edmonds, J D; Edmonds, M; Hunsaker, B D; Kraft, L A; Lawrence, T E; Brewbaker, S; Waite, A R

2012-12-01

Synovex Plus (SP) is a product that delivers 28 mg of estradiol benzoate (EB) and 200 mg of trenbolone acetate (TBA). We studied the impact of a polymeric, porous coating on SP implants (CSP) to prolong release of EB and TBA, and stimulate feedlot performance of feedlot cattle for an extended period. In an explant study, 30 steers were implanted with SP in one ear and CSP in the contralateral ear. Cattle (n = 6/d) were necropsied 40, 81, 120, 160, and 200 d after treatment, and remaining EB and TBA were quantified. Linear regression of EB and TBA remaining as a function of time for each treatment were computed. Rates of EB and TBA depletion from SP were -0.1980 (r(2) = 0.9994) and -1.7073 mg/d (r(2) = 0.9644), respectively, and for CSP rates of EB and TBA depletion were -0.1049 (r(2) = 0.9123) and -0.9466 mg/d (r(2) = 0.9297), respectively. The effect of treatment on depletion rates of each analyte were significant (P < 0.05). Data also showed EB and TBA were delivered from CSP at least 200 d but were delivered from SP about 120 d. Multisite trials with beef-type steers (4 sites) and heifers (4 sites) evaluated feedlot performance and carcass characteristics in response to a CSP implant or when sham implanted (SC). A randomized complete block design with 9 blocks and 2 treatments was used per site within animal gender. Across sites, steers (n = 342, BW = 297 kg) were fed finishing rations for 190 to 202 d (mean 198 d) and heifers (n = 342, BW = 289 kg) were fed finishing rations for 191 to 201 d (mean 198 d). Cattle were harvested and carcasses evaluated. Data were pooled across sites within gender for statistical analysis. Steers and heifers treated with CSP yielded greater (P ≤ 0.003) ADG, DMI, and G:F than SC steers and heifers. Mean BW differences between CSP and SC continued to increase throughout the study, indicating CSP stimulated growth of steers and heifers for 198 d. Mean carcass weights of CSP steers (P = 0.005) and heifers (P = 0.004) were greater than those of SP steers and heifers by 26.2 and 20.6 kg, respectively. The LM area was larger (P < 0.001) in CSP steers and heifers than SC cattle. Marbling decreased with CSP treatment (P ≤ 0.031), which caused reductions (P ≤ 0.006) in proportions of carcasses grading Prime or Choice. Evidence from these studies showed that a single administration of CSP increased feedlot cattle performance for at least 198 d, compared with SC, and may reduce the need to reimplant cattle.

Preservation of vestibular function after scala vestibuli cochlear implantation.

PubMed

Suzuki, Mitsuya; Goto, Takio; Kashio, Akinori; Yasui, Takuya; Sakamoto, Takashi; Ito, Ken; Yamasoba, Tatsuya

2011-10-01

A 58-year-old man, in whom the cochlear implant (CI) had been inserted into the left ear, had right middle-ear cancer. The CI was removed immediately before receiving subtotal removal of right temporal bone. Four months later, the CI was again inserted in his left cochlea. Because of obliterated scala tympani, the 22 active electrodes of the CI were placed into the scala vestibuli. After the surgery, the patient complained that he experienced rotary vertigo and "jumbling of vertical direction" of objects on walking. Using rotation test, we evaluated vestibular function of remaining left ear. Numerous horizontal nystagmus beats were induced during earth-vertical axis rotation, whereas vertical downbeat nystagmus was scarcely induced during off-vertical axis rotation. The horizontal vestibulo-ocular reflex (VOR) was almost normally induced by sinusoidal stimulation at 0.8Hz. These data suggest that the scala vestibuli insertion of CI would be not so invasive against the lateral semicircular canal. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Loudness enhancement and decrement in four paradigms

NASA Technical Reports Server (NTRS)

Elmasian, R.; Galambos, R.; Bernheim, A., Jr.

1980-01-01

When one tone burst (the conditioner) preceeds another (the target) by 100 ms, target loudness is enhanced if the conditioner is more intense and decreased if it is less intense. We show here that similar loudness enhancements and decrements occur when the conditioner follows the target. In all instances, monaural loudness enhancements (in which the conditioner and target are delivered to the same ear) are greater than the dichotic enhancements (in which the conditioner is presented contralaterally), but the decrements, which are smaller than the enhancements, are similar in magnitude. Loudness enhancements and decrements are similar to sequential loudness effects and central tendency effects; the major difference is the relatively very large increases in loudness obtainable in loudness enhancement experiments. We outline a mechanism to account for these loudness phenomena and suggest that this mechanism is responsible for similar perceptual effects that occur in other stimulus dimensions and modalities.

Provision of Auricular Acupuncture and Acupressure in a University Setting

ERIC Educational Resources Information Center

Oyola-Santiago, Tamara; Knopf, Rachel; Robin, Tracy; Harvey, Kristen

2013-01-01

Auricular acupuncture using the National Acupuncture Detoxification Association (NADA) protocol stimulates 5 points in each ear--the Shen Men, sympathetic nervous system, liver, kidney, and lung. This protocol is also known as Acu Detox, and has been used for recovery in community-based settings and drug use treatment programs. It has also been…

Differential effects of unilateral olfactory deprivation on noradrenergic and cholinergic systems in the main olfactory bulb of the rat.

PubMed

Gómez, C; Briñón, J G; Colado, M I; Orio, L; Vidal, M; Barbado, M V; Alonso, J R

2006-09-15

The lack of environmental olfactory stimulation produced by sensory deprivation causes significant changes in the deprived olfactory bulb. Olfactory transmission in the main olfactory bulb (MOB) is strongly modulated by centrifugal systems. The present report examines the effects of unilateral deprivation on the noradrenergic and cholinergic centrifugal systems innervating the MOB. The morphology, distribution, and density of positive axons were studied in the MOBs of control and deprived rats, using dopamine-beta-hydroxylase (DBH)-immunohistochemistry and acetylcholinesterase (AChE) histochemistry in serial sections. Catecholamine content was compared among the different groups of MOBs (control, contralateral, and ipsilateral to the deprivation) using high-performance liquid chromatography analysis. Sensory deprivation revealed that the noradrenergic system developed adaptive plastic changes after olfactory deprivation, including important modifications in its fiber density and distribution, while no differences in cholinergic innervation were observed under the same conditions. The noradrenergic system underwent an important alteration in the glomerular layer, in which some glomeruli showed a dense noradrenergic innervation that was not detected in control animals. The DBH-positive glomeruli with the highest noradrenergic fiber density were compared with AChE-stained sections and it was observed that the strongly noradrenergic-innervated glomeruli were always atypical glomeruli (characterized by their strong degree of cholinergic innervation). In addition to the morphological findings, our biochemical data revealed that olfactory deprivation caused a decrease in the content of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid in the ipsilateral MOB in comparison to the contralateral and control MOBs, together with an increase in noradrenaline levels in both the ipsilateral and contralateral MOBs. Our results show that regulation of the noradrenergic centrifugal system in the MOB depends on environmental olfactory stimulation and that it is highly reactive to sensory deprivation. By contrast, the cholinergic system is fairly stable and does not exhibit clear changes after the loss of sensory inputs.

Choline pathways during normal and stimulated renal growth in rats.

PubMed Central

Bean, G H; Lowenstein, L M

1978-01-01

Cellular membrane synthesis occurs during normal and stimulated renal growth. Choline in the kidney is utilized as a precursor for membrane synthesis via the choline kinase reaction. We investigated choline phosphorylation during normal and stimulated renal growth. Rapidly growing neonatal rat kidneys contained relatively high levels of choline kinase activity (61 pmol phosphorylcholine/min per mg protein). Choline kinase activity and phosphorylcholine production then fell gradually over the 1st mo of life; by 1 mo phosphorylcholine production was 34 pmol phosphorylcholine/min per mg protein. Choline kinase activity increased by 27% (P less than 0.001) in 28-day-old rats when renal growth was stimulated by contralateral nephrectomy; the increase occurred within 2 h after surgery. Thus, changes in the activity of this important enzyme in the initiation of membrane synthesis is associated both with normal renal development and with adaptation to nephron loss. The findings further suggest that the cell membrane may be involved in the initiation of compensatory renal growth. PMID:659614

Second cancer risk after 3D-CRT, IMRT and VMAT for breast cancer.

PubMed

Abo-Madyan, Yasser; Aziz, Muhammad Hammad; Aly, Moamen M O M; Schneider, Frank; Sperk, Elena; Clausen, Sven; Giordano, Frank A; Herskind, Carsten; Steil, Volker; Wenz, Frederik; Glatting, Gerhard

2014-03-01

Second cancer risk after breast conserving therapy is becoming more important due to improved long term survival rates. In this study, we estimate the risks for developing a solid second cancer after radiotherapy of breast cancer using the concept of organ equivalent dose (OED). Computer-tomography scans of 10 representative breast cancer patients were selected for this study. Three-dimensional conformal radiotherapy (3D-CRT), tangential intensity modulated radiotherapy (t-IMRT), multibeam intensity modulated radiotherapy (m-IMRT), and volumetric modulated arc therapy (VMAT) were planned to deliver a total dose of 50 Gy in 2 Gy fractions. Differential dose volume histograms (dDVHs) were created and the OEDs calculated. Second cancer risks of ipsilateral, contralateral lung and contralateral breast cancer were estimated using linear, linear-exponential and plateau models for second cancer risk. Compared to 3D-CRT, cumulative excess absolute risks (EAR) for t-IMRT, m-IMRT and VMAT were increased by 2 ± 15%, 131 ± 85%, 123 ± 66% for the linear-exponential risk model, 9 ± 22%, 82 ± 96%, 71 ± 82% for the linear and 3 ± 14%, 123 ± 78%, 113 ± 61% for the plateau model, respectively. Second cancer risk after 3D-CRT or t-IMRT is lower than for m-IMRT or VMAT by about 34% for the linear model and 50% for the linear-exponential and plateau models, respectively. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Effect of bone conduction transducer placement on distortion product otoacoustic emissions

NASA Astrophysics Data System (ADS)

Hazelbaker, Julie L.

The purpose of this study was to develop a technique to determine the magnitude of bone conducted sound in the cochlea when stimuli are delivered from three different locations on the head. Distortion product otoacoustic emissions (DPOAE) at 1000 and 2000 Hz were used as tools to determine cochlear response to stimuli introduced via air conduction and bone conduction in three subjects. The bone conduction transducer was moved to three head locations (ipsilateral mastoid, contralateral mastoid and forehead). The intensity of the emissions elicited was compared. The differences in DPOAE magnitude created by varying the location of the bone conduction transducer were compared with behavioral threshold differences with the same transducers at the same locations. It was assumed that results of behavioral measures would provide a prediction of the relationship between air and bone conducted DPOAE. However, in the current study, this was not the case. Behavioral bone conduction threshold data did not predict differences in DPOAE at different bone conduction transducer locations. This was a somewhat surprising result and should be considered further in future studies examining the properties of DPOAE elicited by bone conduction. Additionally, a wide band noise masker was introduced to the non-test ear when bone conducted stimuli were introduced to make DPOAE and behavioral test conditions as similar as possible. No great suppression effects were noted across subjects for either frequency. This was likely due to the shape and intensity of the contralateral masked used.

Impedance testing on cochlear implants after electroconvulsive therapy.

PubMed

McRackan, Theodore R; Rivas, Alejandro; Hedley-Williams, Andrea; Raj, Vidya; Dietrich, Mary S; Clark, Nathaniel K; Labadie, Robert F

2014-12-01

Cochlear implants (CI) are neural prostheses that restore hearing to individuals with profound sensorineural hearing loss. The surgically implanted component consists of an electrode array, which is threaded into the cochlea, and an electronic processor, which is buried under the skin behind the ear. The Food and Drug Administration and CI manufacturers contend that electroconvulsive therapy (ECT) is contraindicated in CI recipients owing to risk of damage to the implant and/or the patient. We hypothesized that ECT does no electrical damage to CIs. Ten functional CIs were implanted in 5 fresh cadaveric human heads. Each head then received a consecutive series of 12 unilateral ECT sessions applying maximum full pulse-width energy settings. Electroconvulsive therapy was delivered contralaterally to 5 CIs and ipsilaterally to 5 CIs. Electrical integrity testing (impedance testing) of the electrode array was performed before and after CI insertion, and after the first, third, fifth, seventh, ninth, and 12th ECT sessions. Electroconvulsive therapy was performed by a staff psychiatrist experienced with the technique. Explanted CIs were sent back to the manufacturer for further integrity testing. No electrical damage was identified during impedance testing. Overall, there were statistically significant decreases in impedances (consistent with no electrical damage) when comparing pre-ECT impedance values to those after 12 sessions. There was no statistically significant difference (P > 0.05) in impedance values comparing ipsilateral to contralateral ECT. Manufacturer testing revealed no other electrical damage to the CIs. Electroconvulsive therapy does not seem to cause any detectable electrical injury to CIs.

Intelligibility in speech maskers with a binaural cochlear implant sound coding strategy inspired by the contralateral medial olivocochlear reflex.

PubMed

Lopez-Poveda, Enrique A; Eustaquio-Martín, Almudena; Stohl, Joshua S; Wolford, Robert D; Schatzer, Reinhold; Gorospe, José M; Ruiz, Santiago Santa Cruz; Benito, Fernando; Wilson, Blake S

2017-05-01

We have recently proposed a binaural cochlear implant (CI) sound processing strategy inspired by the contralateral medial olivocochlear reflex (the MOC strategy) and shown that it improves intelligibility in steady-state noise (Lopez-Poveda et al., 2016, Ear Hear 37:e138-e148). The aim here was to evaluate possible speech-reception benefits of the MOC strategy for speech maskers, a more natural type of interferer. Speech reception thresholds (SRTs) were measured in six bilateral and two single-sided deaf CI users with the MOC strategy and with a standard (STD) strategy. SRTs were measured in unilateral and bilateral listening conditions, and for target and masker stimuli located at azimuthal angles of (0°, 0°), (-15°, +15°), and (-90°, +90°). Mean SRTs were 2-5 dB better with the MOC than with the STD strategy for spatially separated target and masker sources. For bilateral CI users, the MOC strategy (1) facilitated the intelligibility of speech in competition with spatially separated speech maskers in both unilateral and bilateral listening conditions; and (2) led to an overall improvement in spatial release from masking in the two listening conditions. Insofar as speech is a more natural type of interferer than steady-state noise, the present results suggest that the MOC strategy holds potential for promising outcomes for CI users. Copyright © 2017. Published by Elsevier B.V.

TRANSCUTANEOUS CERVICAL VAGUS NERVE STIMULATION AMELIORATES ACUTE ISCHEMIC INJURY IN RATS

PubMed Central

Ay, Ilknur; Nasser, Rena; Simon, Bruce; Ay, Hakan

2016-01-01

Background Direct stimulation of the vagus nerve in the neck via surgically implanted electrodes is protective in animal models of stroke. We sought to determine the safety and efficacy of a non-invasive cervical VNS (nVNS) method using surface electrodes applied to the skin overlying the vagus nerve in the neck in a model of middle cerebral artery occlusion (MCAO). Methods nVNS was initiated variable times after MCAO hour in rats (n=33). Control animals received sham stimulation (n=33). Infarct volume and functional outcome were assessed on day 7. Brains were processed by immunohistochemistry for microglial activation and cytokine levels. The ability of nVNS to activate the nucleus tractus solitarius (NTS) was assessed using c-Fos immunohistochemistry. Results Infarct volume was 43.15±3.36 percent of the contralateral hemisphere (PCH) in control and 28.75±4.22 PCH in nVNS-treated animals (p<0.05). The effect of nVNS on infarct size was consistent when stimulation was initiated up to 4 hours after MCAO. There was no difference in heart rate and blood pressure between control and nVNS-treated animals. The number of c-Fos positive cells was 32.4±10.6 and 6.2±6.3 in the ipsilateral NTS (p<0.05) and 30.4±11.2 and 5.8±4.3 in the contralateral NTS (p<0.05) in nVNS-treated and control animals, respectively. nVNS reduced the number of Iba-1, CD68, and TNF-α positive cells and increased the number of HMGB1 positive cells. Conclusions nVNS inhibits ischemia-induced immune activation and reduces the extent of tissue injury and functional deficit in rats without causing cardiac or hemodynamic adverse effects when initiated up to 4 hours after MCAO. PMID:26723020

Central-peripheral neural network interactions evoked by vagus nerve stimulation: functional consequences on control of cardiac function.

PubMed

Ardell, Jeffrey L; Rajendran, Pradeep S; Nier, Heath A; KenKnight, Bruce H; Armour, J Andrew

2015-11-15

Using vagus nerve stimulation (VNS), we sought to determine the contribution of vagal afferents to efferent control of cardiac function. In anesthetized dogs, the right and left cervical vagosympathetic trunks were stimulated in the intact state, following ipsilateral or contralateral vagus nerve transection (VNTx), and then following bilateral VNTx. Stimulations were performed at currents from 0.25 to 4.0 mA, frequencies from 2 to 30 Hz, and a 500-μs pulse width. Right or left VNS evoked significantly greater current- and frequency-dependent suppression of chronotropic, inotropic, and lusitropic function subsequent to sequential VNTx. Bradycardia threshold was defined as the current first required for a 5% decrease in heart rate. The threshold for the right vs. left vagus-induced bradycardia in the intact state (2.91 ± 0.18 and 3.47 ± 0.20 mA, respectively) decreased significantly with right VNTx (1.69 ± 0.17 mA for right and 3.04 ± 0.27 mA for left) and decreased further following bilateral VNTx (1.29 ± 0.16 mA for right and 1.74 ± 0.19 mA for left). Similar effects were observed following left VNTx. The thresholds for afferent-mediated effects on cardiac parameters were 0.62 ± 0.04 and 0.65 ± 0.06 mA with right and left VNS, respectively, and were reflected primarily as augmentation. Afferent-mediated tachycardias were maintained following β-blockade but were eliminated by VNTx. The increased effectiveness and decrease in bradycardia threshold with sequential VNTx suggest that 1) vagal afferents inhibit centrally mediated parasympathetic efferent outflow and 2) the ipsilateral and contralateral vagi exert a substantial buffering capacity. The intact threshold reflects the interaction between multiple levels of the cardiac neural hierarchy. Copyright © 2015 the American Physiological Society.

Central-peripheral neural network interactions evoked by vagus nerve stimulation: functional consequences on control of cardiac function

PubMed Central

Rajendran, Pradeep S.; Nier, Heath A.; KenKnight, Bruce H.; Armour, J. Andrew

2015-01-01

Using vagus nerve stimulation (VNS), we sought to determine the contribution of vagal afferents to efferent control of cardiac function. In anesthetized dogs, the right and left cervical vagosympathetic trunks were stimulated in the intact state, following ipsilateral or contralateral vagus nerve transection (VNTx), and then following bilateral VNTx. Stimulations were performed at currents from 0.25 to 4.0 mA, frequencies from 2 to 30 Hz, and a 500-μs pulse width. Right or left VNS evoked significantly greater current- and frequency-dependent suppression of chronotropic, inotropic, and lusitropic function subsequent to sequential VNTx. Bradycardia threshold was defined as the current first required for a 5% decrease in heart rate. The threshold for the right vs. left vagus-induced bradycardia in the intact state (2.91 ± 0.18 and 3.47 ± 0.20 mA, respectively) decreased significantly with right VNTx (1.69 ± 0.17 mA for right and 3.04 ± 0.27 mA for left) and decreased further following bilateral VNTx (1.29 ± 0.16 mA for right and 1.74 ± 0.19 mA for left). Similar effects were observed following left VNTx. The thresholds for afferent-mediated effects on cardiac parameters were 0.62 ± 0.04 and 0.65 ± 0.06 mA with right and left VNS, respectively, and were reflected primarily as augmentation. Afferent-mediated tachycardias were maintained following β-blockade but were eliminated by VNTx. The increased effectiveness and decrease in bradycardia threshold with sequential VNTx suggest that 1) vagal afferents inhibit centrally mediated parasympathetic efferent outflow and 2) the ipsilateral and contralateral vagi exert a substantial buffering capacity. The intact threshold reflects the interaction between multiple levels of the cardiac neural hierarchy. PMID:26371171

fMRI and MRS measures of neuroplasticity in the pharyngeal motor cortex

PubMed Central

Michou, Emilia; Williams, Steve; Vidyasagar, Rishma; Downey, Darragh; Mistry, Satish; Edden, Richard A.E.; Hamdy, Shaheen

2016-01-01

Introduction Paired associative stimulation (PAS), is a novel non-invasive technique where two neural substrates are employed in a temporally coordinated manner in order to modulate cortico-motor excitability within the motor cortex (M1). In swallowing, combined pharyngeal electrical and transcranial-magnetic-stimulation induced beneficial neurophysiological and behavioural effects in healthy subjects and dysphagic stroke patients. Here, we aimed to investigate the whole-brain changes in neural activation during swallowing using functional magnetic resonance imaging (fMRI) following PAS application and in parallel assess associated GABA changes with magnetic resonance spectroscopy (MRS). Methods Healthy adults (n = 11, 38 ± 9 years old) were randomised to receive real and sham PAS to the ‘stronger’ motor cortex pharyngeal representation, on 2 separate visits. Following PAS, event-related fMRI was performed to assess changes in brain activation in response to water and saliva swallowing and during rest. Data were analysed (SPM8) at P < .001. MRS data were acquired using MEGA-PRESS before and after the fMRI acquisitions on both visits and GABA concentrations were measured (AMARES, jMRUI). Results Following real PAS, BOLD signal changes (group analyses) increased at the site of stimulation during water and saliva swallowing, compared to sham PAS. It is also evident that PAS induced significant increases in BOLD signal to contralateral (to stimulation) hemispheric areas that are of importance to the swallowing neural network. Following real PAS, GABA: creatine ratio showed a trend to increase contralateral to PAS. Conclusion Targeted PAS applied to the human pharyngeal motor cortex induces local and remote changes in both primary and non-primary areas for water and saliva tasks. There is a possibility that changes of the inhibitory neurotransmitter, GABA, may play a role in the changes in BOLD signal. These findings provide evidence for the mechanisms underlying the beneficial effects of PAS on the brain swallowing network. PMID:25976926

Effect of neck flexion on somatosensory and motor evoked potentials in Hirayama disease.

PubMed

Abraham, A; Gotkine, M; Drory, V E; Blumen, S C

2013-11-15

Hirayama disease (HD) is a rare motor disorder mainly affecting young men, characterized by atrophy and weakness of forearm and hand muscles corresponding to a C7-T1 myotome distribution. The weakness is usually unilateral or asymmetric and progression usually stops within several years. The etiology of HD is not well understood. One hypothesis, mainly based on MRI findings, is that the weakness is a consequence of cervical flexion myelopathy. The aim of this study was to explore the function of corticospinal and ascending somatosensory pathways during neck flexion using evoked responses. 15 men with HD and 7 age-matched control male subjects underwent somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) studies with the neck in neutral position and fully flexed. SSEP studies included electrical stimulation of median and ulnar nerves at the wrist, and tibial nerve at the ankle with recording over the ipsilateral Erb's point, cervical spine, and contralateral sensory cortex. MEP recordings were obtained by magnetic stimulation of the motor cortex and the cervical lower spinal roots; the evoked responses were recorded from the contralateral thenar and abductor hallucis muscles. MEP recordings demonstrated significant lower amplitudes, and slightly prolonged latencies in HD patients on cervical stimulation, compared to control subjects. During neck flexion, MEP studies also demonstrated a statistically significant drop in mean upper limb amplitude on cervical stimulation in HD patients, as well as in control subjects, although to a lesser degree. In contrast, no significant differences were found in SSEP studies in HD patients compared to control subjects, or between neutral and flexed position in these groups. The study shows a negative effect of cervical flexion on MEP amplitudes in HD patients as well as in control subjects, requiring more studies to investigate its significance. Neck flexion did not have an influence on any SSEP parameters in patients or controls. © 2013 Elsevier B.V. All rights reserved.

In vivo sup 31 P-NMR spectroscopy of chronically stimulated canine skeletal muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, B.J. III; McCully, A.K.; Subramanian, H.V.

1988-02-01

Chronic stimulation converts skeletal muscle of mixed fiber type to a uniform muscle made up of type I, fatigue-resistant fibers. Here, the bioenergetic correlates of fatigue resistance in conditioned canine latissimus dorsi are assessed with in vivo phosphorus-31 nuclear magnetic resonance ({sup 31}P-NMR) spectroscopy. After chronic electrical stimulation, five dogs underwent {sup 31}P-NMR spectroscopic and isometric tension measurements on conditioned and contralateral control muscle during stimulation for 200, 300, 500, and 800 ms of an 1,100-ms duty cycle. With stimulation, phosphocreatine (PCr) fell proportional to the degree of stimulation in both conditioned and control muscle but fell significantly less inmore » conditioned muscle at all the least intense stimulation period (200 ms). Isometric tension, expressed as a tension time index per gram muscle, was significantly greater in the conditioned muscle at the two longest stimulation periods. The overall small change in PCr and the lack of a plateau in tension observed in the conditioned muscle are similar to that seen in cardiac muscle during increased energy demand. This study indicates that the conditioned muscle's markedly enhanced resistance to fatigue is in part the result of its increased capacity for oxidative phosphorylation.« less

A New Intraoperative Real-time Monitoring System for Reconstructive Middle Ear Surgery: An Experimental and Clinical Feasibility Study.

PubMed

Zahnert, Thomas; Metasch, Marie-Luise; Seidler, Hannes; Bornitz, Matthias; Lasurashvili, Nicoloz; Neudert, Marcus

2016-12-01

Electromagnetical excitation of ossicular vibration is suitable for middle ear transmission measurements in the experimental and clinical setting. Thereby, it can be used as a real-time monitoring system for quality control in ossiculoplasty. Positioning and coupling of middle ear prosthesis are a precondition for good postoperative hearing results, but at the same time completely dependent upon the surgeon's subjective judgment during surgery. We evaluated an electromagnetically driven measurement system that enables for in vitro and in vivo transmission measurements and thus can be used as a real-time monitoring tool in ossicular reconstruction. For electromagnetical excitation a magnet was placed on the umbo of the malleus handle and driven by a magnetic field. The induced stapes displacement was picked up by laser Doppler vibrometry on the footplate. Measurements were performed on the intact ossicular chain in five cadaveric temporal bones and during five cochlear implant surgeries. Additionally, two ossiculoplasties were performed under real-time transmission feedback with the monitoring system. Experimentally, the equivalent sound pressure level of the electromagnetic excitation was about 70 to 80 dB which is 10 to 20 dB less than the acoustic stimulation. In the intraoperative setup the generated stapes displacements were about 5 to 20 dB smaller compared with the temporal bone experiments. Applied as real-time feedback system, an improvement in the middle ear transfer function of 4.5 dB in total and 20 dB in partial ossicular reconstruction were achieved. The electromagnetical excitation and measurement system is comparable to the gold standard with acoustical stimulation in both, the experimental setup in temporal bones as well as in vivo. The technical feasibility of the electromagnetical excitation method has been proven and it is shown that it can be used as a real-time monitoring system for ossiculoplasty in the operation room.

Neural correlates of mirth and laughter: a direct electrical cortical stimulation study.

PubMed

Yamao, Yukihiro; Matsumoto, Riki; Kunieda, Takeharu; Shibata, Sumiya; Shimotake, Akihiro; Kikuchi, Takayuki; Satow, Takeshi; Mikuni, Nobuhiro; Fukuyama, Hidenao; Ikeda, Akio; Miyamoto, Susumu

2015-05-01

Laughter consists of both motor and emotional aspects. The emotional component, known as mirth, is usually associated with the motor component, namely, bilateral facial movements. Previous electrical cortical stimulation (ES) studies revealed that mirth was associated with the basal temporal cortex, inferior frontal cortex, and medial frontal cortex. Functional neuroimaging implicated a role for the left inferior frontal and bilateral temporal cortices in humor processing. However, the neural origins and pathways linking mirth with facial movements are still unclear. We hereby report two cases with temporal lobe epilepsy undergoing subdural electrode implantation in whom ES of the left basal temporal cortex elicited both mirth and laughter-related facial muscle movements. In one case with normal hippocampus, high-frequency ES consistently caused contralateral facial movement, followed by bilateral facial movements with mirth. In contrast, in another case with hippocampal sclerosis (HS), ES elicited only mirth at low intensity and short duration, and eventually laughter at higher intensity and longer duration. In both cases, the basal temporal language area (BTLA) was located within or adjacent to the cortex where ES produced mirth. In conclusion, the present direct ES study demonstrated that 1) mirth had a close relationship with language function, 2) intact mesial temporal structures were actively engaged in the beginning of facial movements associated with mirth, and 3) these emotion-related facial movements had contralateral dominance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Frontoparietal regions may become hypoactive after intermittent theta burst stimulation over the contralateral homologous cortex in humans.

PubMed

He, Xiaofei; Lan, Yue; Xu, Guangqing; Mao, Yurong; Chen, Zhenghong; Huang, Dongfeng; Pei, Zhong

2013-12-01

Brain injury to the dorsal frontoparietal networks, including the posterior parietal cortex (PPC) and dorsolateral prefrontal cortex (DLPFC), commonly cause spatial neglect. However, the interaction of these different regions in spatial attention is unclear. The aim of the present study was to investigate whether hyperexcitable neural networks can cause an abnormal interhemispheric inhibition. The Attention Network Test was used to test subjects following intermittent theta burst stimulation (iTBS) to the left or right frontoparietal networks. During the Attention Network Test task, all subjects tolerated each conditioning iTBS without any obvious iTBS-related side effects. Subjects receiving real-right-PPC iTBS showed significant enhancement in both alerting and orienting efficiency compared with those receiving either sham-right-PPC iTBS or real-left-PPC iTBS. Moreover, subjects exposed to the real-right-DLPFC iTBS exhibited significant improvement in both alerting and executive control efficiency, compared with those exposed to either the sham-right-DLPFC or real-left-DLPFC conditioning. Interestingly, compared with subjects exposed to the sham-left-PPC stimuli, subjects exposed to the real-left-PPC iTBS had a significant deficit in the orienting index. The present study indicates that iTBS over the contralateral homologous cortex may induce the hypoactivity of the right PPC through interhemispheric competition in spatial orienting attention.

Stability of the Medial Olivocochlear Reflex as Measured by Distortion Product Otoacoustic Emissions

PubMed Central

Abdala, Carolina

2015-01-01

Purpose The purpose of this study was to assess the repeatability of a fine-resolution, distortion product otoacoustic emission (DPOAE)–based assay of the medial olivocochlear (MOC) reflex in normal-hearing adults. Method Data were collected during 36 test sessions from 4 normal-hearing adults to assess short-term stability and 5 normal-hearing adults to assess long-term stability. DPOAE level and phase measurements were recorded with and without contralateral acoustic stimulation. MOC reflex indices were computed by (a) noting contralateral acoustic stimulation-induced changes in DPOAE level (both absolute and normalized) at fine-structure peaks, (b) recording the effect as a vector difference, and (c) separating DPOAE components and considering a component-specific metric. Results Analyses indicated good repeatability of all indices of the MOC reflex in most frequency ranges. Short- and long-term repeatability were generally comparable. Indices normalized to a subject's own baseline fared best, showing strong short- and long-term stability across all frequency intervals. Conclusions These results suggest that fine-resolution DPOAE-based measures of the MOC reflex measured at strategic frequencies are stable, and natural variance from day-to-day or week-to-week durations is small enough to detect between-group differences and possibly to monitor intervention-related success. However, this is an empirical question that must be directly tested to confirm its utility. PMID:25320951

Neuroimaging and cognitive changes during déjà vu.

PubMed

Kovacs, Norbert; Auer, Tibor; Balas, Istvan; Karadi, Kazmer; Zambo, Katalin; Schwarcz, Attila; Klivenyi, Peter; Jokeit, Hennric; Horvath, Krisztina; Nagy, Ferenc; Janszky, Jozsef

2009-01-01

The cause or the physiological role of déjà vu (DV) in healthy people is unknown. The pathophysiology of DV-type epileptic aura is also unresolved. Here we describe a 22-year-old woman treated with deep brain stimulation (DBS) of the left internal globus pallidus for hemidystonia. At certain stimulation settings, DBS elicited reproducible episodes of DV. Neuropsychological tests and single-photon-emission computed tomography (SPECT) were performed during DBS-evoked DV and during normal DBS stimulation without DV. SPECT during DBS-evoked DV revealed hyperperfusion of the right (contralateral to the electrode) hippocampus and other limbic structures. Neuropsychological examinations performed during several evoked DV episodes revealed disturbances in nonverbal memory. Our results confirm the role of mesiotemporal structures in the pathogenesis of DV. We hypothesize that individual neuroanatomy and disturbances in gamma oscillations or in the dopaminergic system played a role in DBS-elicited DV in our patient.

Lateralized delay period activity marks the focus of spatial attention in working memory: evidence from somatosensory event-related brain potentials.

PubMed

Katus, Tobias; Eimer, Martin

2015-04-29

The short-term retention of sensory information in working memory (WM) is known to be associated with a sustained enhancement of neural activity. What remains controversial is whether this neural trace indicates the sustained storage of information or the allocation of attention. To evaluate the storage and attention accounts, we examined sustained tactile contralateral delay activity (tCDA component) of the event-related potential. The tCDA manifests over somatosensory cortex contralateral to task-relevant tactile information during stimulus retention. Two tactile sample sets (S1, S2) were presented sequentially, separated by 1.5 s. Each set comprised two stimuli, one per hand. Human participants memorized the location of one task-relevant stimulus per sample set and judged whether one of these locations was stimulated again at memory test. The two relevant pulses were unpredictably located on the same hand (stay trials) or on different hands (shift trials). Initially, tCDA components emerged contralateral to the relevant S1 pulse. Sequential loading of WM enhanced the tCDA after S2 was presented on stay trials. On shift trials, the tCDA's polarity reversed after S2 presentation, resulting in delay activity that was now contralateral to the task-relevant S2 pulse. The disappearance of a lateralized neural trace for the relevant S1 pulse did not impair memory accuracy for this stimulus on shift trials. These results contradict the storage account and suggest that delay period activity indicates the sustained engagement of an attention-based rehearsal mechanism. In conclusion, somatosensory delay period activity marks the current focus of attention in tactile WM. Copyright © 2015 the authors 0270-6474/15/356689-07$15.00/0.

Effect of Thyroid Remnant Volume on the Risk of Hypothyroidism After Hemithyroidectomy: A Prospective Study.

PubMed

Lang, Brian Hung-Hin; Wong, Carlos K H; Wong, Kai Pun; Chu, Kelvin Ka-Wan; Shek, Tony W H

2017-06-01

Hypothyroidism is a common sequel after a hemithyroidectomy. Although various risk factors leading to hypothyroidism have been reported, the effect of the contralateral lobe's volume has been understudied. This study aimed to examine the association between the preoperative contralateral lobe's volume and the risk of postoperative hypothyroidism. During a 2-year period, 150 eligible patients undergoing a hemithyroidectomy were evaluated. The volume of the contralateral nonexcised lobe was estimated preoperatively by independent assessors on ultrasonography using the following formula: width (in cm) × depth (in cm) × length (in cm) × (π/6), adjusted for the body surface area (BSA). Postoperative hypothyroidism was defined as serum thyroid-stimulating hormone (TSH) exceeding 4.78 mIU/L. Any significant characteristics in the univariate analysis were entered into the multivariate analysis to determine independent factors. After a mean follow-up period of 53.5 ± 9.4 months, 44 patients (29.3 %) experienced postoperative hypothyroidism, and 10 of these patients required thyroxine replacement. Hypothyroidism was associated with a higher preoperative TSH level (p < 0.001), a smaller BSA-adjusted volume (p < 0.001), fewer ipsilateral nodules (p = 0.037), and the presence of thyroiditis (p = 0.050). After adjustment for thyroiditis, preoperative TSH (p < 0.001), number of ipsilateral nodules (p = 0.048), and BSA-adjusted volume (p < 0.001) were independent factors for hypothyroidism. Patients with a BSA-adjusted volume smaller than 3.2 ml had a threefold greater hypothyroidism risk than those with a BSA-adjusted volume of 3.2 ml or more (p < 0.001). A significant inverse association between the preoperative contralateral lobe's volume and hypothyroidism risk was observed after hemithyroidectomy. Together with a higher preoperative TSH level and fewer ipsilateral nodules, a smaller BSA-adjusted volume measured by preoperative ultrasonography independently predicted hypothyroidism.

Frequency-dependent, transient effects of subthalamic nucleus deep brain stimulation on methamphetamine-induced circling and neuronal activity in the hemiparkinsonian rat.

PubMed

So, Rosa Q; McConnell, George C; Grill, Warren M

2017-03-01

Methamphetamine-induced circling is used to quantify the behavioral effects of subthalamic nucleus (STN) deep brain stimulation (DBS) in hemiparkinsonian rats. We observed a frequency-dependent transient effect of DBS on circling, and quantified this effect to determine its neuronal basis. High frequency STN DBS (75-260Hz) resulted in transient circling contralateral to the lesion at the onset of stimulation, which was not sustained after the first several seconds of stimulation. Following the transient behavioral change, DBS resulted in a frequency-dependent steady-state reduction in pathological ipsilateral circling, but no change in overall movement. Recordings from single neurons in globus pallidus externa (GPe) and substantia nigra pars reticulata (SNr) revealed that high frequency, but not low frequency, STN DBS elicited transient changes in both firing rate and neuronal oscillatory power at the stimulation frequency in a subpopulation of GPe and SNr neurons. These transient changes were not sustained, and most neurons exhibited a different response during the steady-state phase of DBS. During the steady-state, DBS produced elevated neuronal oscillatory power at the stimulus frequency in a majority of GPe and SNr neurons, and the increase was more pronounced during high frequency DBS than during low frequency DBS. Changes in oscillatory power during both transient and steady-state DBS were highly correlated with changes in firing rates. These results suggest that distinct neural mechanisms were responsible for transient and sustained behavioral responses to STN DBS. The transient contralateral turning behavior following the onset of high frequency DBS was paralleled by transient changes in firing rate and oscillatory power in the GPe and SNr, while steady-state suppression of ipsilateral turning was paralleled by sustained increased synchronization of basal ganglia neurons to the stimulus pulses. Our analysis of distinct frequency-dependent transient and steady-state responses to DBS lays the foundation for future mechanistic studies of the immediate and persistent effects of DBS. Copyright © 2016 Elsevier B.V. All rights reserved.

Episodic Memory Retrieval Functionally Relies on Very Rapid Reactivation of Sensory Information.

PubMed

Waldhauser, Gerd T; Braun, Verena; Hanslmayr, Simon

2016-01-06

Episodic memory retrieval is assumed to rely on the rapid reactivation of sensory information that was present during encoding, a process termed "ecphory." We investigated the functional relevance of this scarcely understood process in two experiments in human participants. We presented stimuli to the left or right of fixation at encoding, followed by an episodic memory test with centrally presented retrieval cues. This allowed us to track the reactivation of lateralized sensory memory traces during retrieval. Successful episodic retrieval led to a very early (∼100-200 ms) reactivation of lateralized alpha/beta (10-25 Hz) electroencephalographic (EEG) power decreases in the visual cortex contralateral to the visual field at encoding. Applying rhythmic transcranial magnetic stimulation to interfere with early retrieval processing in the visual cortex led to decreased episodic memory performance specifically for items encoded in the visual field contralateral to the site of stimulation. These results demonstrate, for the first time, that episodic memory functionally relies on very rapid reactivation of sensory information. Remembering personal experiences requires a "mental time travel" to revisit sensory information perceived in the past. This process is typically described as a controlled, relatively slow process. However, by using electroencephalography to measure neural activity with a high time resolution, we show that such episodic retrieval entails a very rapid reactivation of sensory brain areas. Using transcranial magnetic stimulation to alter brain function during retrieval revealed that this early sensory reactivation is causally relevant for conscious remembering. These results give first neural evidence for a functional, preconscious component of episodic remembering. This provides new insight into the nature of human memory and may help in the understanding of psychiatric conditions that involve the automatic intrusion of unwanted memories. Copyright © 2016 the authors 0270-6474/16/360251-10$15.00/0.

Transcranial Direct Current Stimulation (tDCS) Enhances the Excitability of Trigemino-Facial Reflex Circuits.

PubMed

Cabib, Christopher; Cipullo, Federica; Morales, Merche; Valls-Solé, Josep

2016-01-01

Transcranial direct current stimulation (tDCS) causes a tiny burning sensation through activation of local cutaneous trigeminal afferents. Trigeminal sensory inputs from tDCS may generate excitability changes in the trigemino-facial reflex circuits. Sixteen healthy volunteers were submitted to 20 minutes tDCS sessions with two types of electrode-montage conditions: 1. Real vs Sham 'bi-hemispheric' tDCS (cathode/anode: C4/C3), for blinded assessment of effects, and 2. 'uni-hemispheric' tDCS (cathode/anode: Fp3/C3), for assessment of laterality of the effects. Supraorbital nerve stimuli were used to obtain blink reflexes before, during (10 minutes from onset) and after (30 minutes from onset) the tDCS session. Outcome measures were R2 habituation (R2H) to repeated stimuli, the blink reflex excitability recovery (BRER) to paired stimuli and the blink reflex inhibition by a prepulse (BRIP). Real but not sham bi-hemispheric tDCS caused a significant decrease of R2H and leftward shift of BRER curve (p < 0.05 for all measures). The effects of uni-hemispheric tDCS on BRER and BRIP were larger on ipsilateral than on contralateral blink reflexes (p < 0.05). Excitability changes were still present 10 minutes after the end of stimulation in a lesser extent. This study shows that 20 minute tDCS enhances the excitability of trigemino-facial reflex circuits. The finding of larger ipsilateral than contralateral effects suggests that sensitization through cutaneous trigeminal afferents adds on other possible mechanisms such as activation of cortico-nuclear or cortico-reticular connections. Copyright © 2016 Elsevier Inc. All rights reserved.

Thalamic DBS with a constant-current device in essential tremor: A controlled clinical trial.

PubMed

Wharen, Robert E; Okun, Michael S; Guthrie, Barton L; Uitti, Ryan J; Larson, Paul; Foote, Kelly; Walker, Harrison; Marshall, Frederick J; Schwalb, Jason; Ford, Blair; Jankovic, Joseph; Simpson, Richard; Dashtipour, Khashayar; Phibbs, Fenna; Neimat, Joseph S; Stewart, R Malcolm; Peichel, DeLea; Pahwa, Rajesh; Ostrem, Jill L

2017-07-01

This study of thalamic deep brain stimulation (DBS) investigated whether a novel constant-current device improves tremor and activities of daily living (ADL) in patients with essential tremor (ET). A prospective, controlled, multicenter study was conducted at 12 academic centers. We investigated the safety and efficacy of unilateral and bilateral constant-current DBS of the ventralis intermedius (VIM) nucleus of the thalamus in patients with essential tremor whose tremor was inadequately controlled by medications. The primary outcome measure was a rater-blinded assessment of the change in the target limb tremor score in the stimulation-on versus stimulation-off state six months following surgery. Multiple secondary outcomes were assessed at one-year follow-up, including motor, mood, and quality-of-life measures. 127 patients were implanted with VIM DBS. The blinded, primary outcome variable (n = 76) revealed a mean improvement of 1.25 ± 1.26 points in the target limb tremor rating scale (TRS) score in the arm contralateral to DBS (p < 0.001). Secondary outcome variables at one year revealed significant improvements (p ≤ 0.001) in quality of life, depression symptoms, and ADL scores. Forty-seven patients had a second contralateral VIM-DBS, and this group demonstrated reduction in second-sided tremor at 180 days (p < 0.001). Serious adverse events related to the surgery included infection (n = 3), intracranial hemorrhage (n = 3), and device explantation (n = 3). Unilateral and bilateral constant-current VIM DBS significantly improves upper extremity tremor, ADL, quality of life, and depression in patients with severe ET. Copyright © 2017 Elsevier Ltd. All rights reserved.

Finite element modelling of sound transmission from outer to inner ear.

PubMed

Areias, Bruno; Santos, Carla; Natal Jorge, Renato M; Gentil, Fernanda; Parente, Marco Pl

2016-11-01

The ear is one of the most complex organs in the human body. Sound is a sequence of pressure waves, which propagates through a compressible media such as air. The pinna concentrates the sound waves into the external auditory meatus. In this canal, the sound is conducted to the tympanic membrane. The tympanic membrane transforms the pressure variations into mechanical displacements, which are then transmitted to the ossicles. The vibration of the stapes footplate creates pressure waves in the fluid inside the cochlea; these pressure waves stimulate the hair cells, generating electrical signals which are sent to the brain through the cochlear nerve, where they are decoded. In this work, a three-dimensional finite element model of the human ear is developed. The model incorporates the tympanic membrane, ossicular bones, part of temporal bone (external auditory meatus and tympanic cavity), middle ear ligaments and tendons, cochlear fluid, skin, ear cartilage, jaw and the air in external auditory meatus and tympanic cavity. Using the finite element method, the magnitude and the phase angle of the umbo and stapes footplate displacement are calculated. Two slightly different models are used: one model takes into consideration the presence of air in the external auditory meatus while the other does not. The middle ear sound transfer function is determined for a stimulus of 60 dB SPL, applied to the outer surface of the air in the external auditory meatus. The obtained results are compared with previously published data in the literature. This study highlights the importance of external auditory meatus in the sound transmission. The pressure gain is calculated for the external auditory meatus.

Close-field electroporation gene delivery using the cochlear implant electrode array enhances the bionic ear.

PubMed

Pinyon, Jeremy L; Tadros, Sherif F; Froud, Kristina E; Y Wong, Ann C; Tompson, Isabella T; Crawford, Edward N; Ko, Myungseo; Morris, Renée; Klugmann, Matthias; Housley, Gary D

2014-04-23

The cochlear implant is the most successful bionic prosthesis and has transformed the lives of people with profound hearing loss. However, the performance of the "bionic ear" is still largely constrained by the neural interface itself. Current spread inherent to broad monopolar stimulation of the spiral ganglion neuron somata obviates the intrinsic tonotopic mapping of the cochlear nerve. We show in the guinea pig that neurotrophin gene therapy integrated into the cochlear implant improves its performance by stimulating spiral ganglion neurite regeneration. We used the cochlear implant electrode array for novel "close-field" electroporation to transduce mesenchymal cells lining the cochlear perilymphatic canals with a naked complementary DNA gene construct driving expression of brain-derived neurotrophic factor (BDNF) and a green fluorescent protein (GFP) reporter. The focusing of electric fields by particular cochlear implant electrode configurations led to surprisingly efficient gene delivery to adjacent mesenchymal cells. The resulting BDNF expression stimulated regeneration of spiral ganglion neurites, which had atrophied 2 weeks after ototoxic treatment, in a bilateral sensorineural deafness model. In this model, delivery of a control GFP-only vector failed to restore neuron structure, with atrophied neurons indistinguishable from unimplanted cochleae. With BDNF therapy, the regenerated spiral ganglion neurites extended close to the cochlear implant electrodes, with localized ectopic branching. This neural remodeling enabled bipolar stimulation via the cochlear implant array, with low stimulus thresholds and expanded dynamic range of the cochlear nerve, determined via electrically evoked auditory brainstem responses. This development may broadly improve neural interfaces and extend molecular medicine applications.

DNA damage signaling regulates age-dependent proliferative capacity of quiescent inner ear supporting cells

PubMed Central

Laos, Maarja; Anttonen, Tommi; Kirjavainen, Anna; Hällström, Taija af; Laiho, Marikki; Pirvola, Ulla

2014-01-01

Supporting cells (SCs) of the cochlear (auditory) and vestibular (balance) organs hold promise as a platform for therapeutic regeneration of the sensory hair cells. Prior data have shown proliferative restrictions of adult SCs forced to re-enter the cell cycle. By comparing juvenile and adult SCs in explant cultures, we have here studied how proliferative restrictions are linked with DNA damage signaling. Cyclin D1 overexpression, used to stimulate cell cycle re-entry, triggered higher proliferative activity of juvenile SCs. Phosphorylated form of histone H2AX (γH2AX) and p53 binding protein 1 (53BP1) were induced in a foci-like pattern in SCs of both ages as an indication of DNA double-strand break formation and activated DNA damage response. Compared to juvenile SCs, γH2AX and the repair protein Rad51 were resolved with slower kinetics in adult SCs, accompanied by increased apoptosis. Consistent with the in vitro data, in a Rb mutant mouse model in vivo, cell cycle re-entry of SCs was associated with γH2AX foci induction. In contrast to cell cycle reactivation, pharmacological stimulation of SC-to-hair-cell transdifferentiation in vitro did not trigger γH2AX. Thus, DNA damage and its prolonged resolution are critical barriers in the efforts to stimulate proliferation of the adult inner ear SCs. PMID:25063730

VAGUS NERVE STIMULATION REGULATES HEMOSTASIS IN SWINE

PubMed Central

Czura, Christopher J.; Schultz, Arthur; Kaipel, Martin; Khadem, Anna; Huston, Jared M.; Pavlov, Valentin A.; Redl, Heinz; Tracey, Kevin J.

2010-01-01

The central nervous system regulates peripheral immune responses via the vagus nerve, the primary neural component of the cholinergic anti-inflammatory pathway. Electrical stimulation of the vagus nerve suppresses pro-inflammatory cytokine release in response to endotoxin, I/R injury, and hypovolemic shock and protects against lethal hypotension. To determine the effect of vagus nerve stimulation on coagulation pathways, anesthetized pigs were subjected to partial ear resection before and after electrical vagus nerve stimulation. We observed that electrical vagus nerve stimulation significantly decreased bleeding time (pre–electrical vagus nerve stimulation = 1033 ± 210 s versus post–electrical vagus nerve stimulation = 585 ± 111 s; P < 0.05) and total blood loss (pre–electrical vagus nerve stimulation = 48.4 ± 6.8 mL versus post–electrical vagus nerve stimulation = 26.3 ± 6.7 mL; P < 0.05). Reduced bleeding time after vagus nerve stimulation was independent of changes in heart rate or blood pressure and correlated with increased thrombin/antithrombin III complex generation in shed blood. These data indicate that electrical stimulation of the vagus nerve attenuates peripheral hemorrhage in a porcine model of soft tissue injury and that this protective effect is associated with increased coagulation factor activity. PMID:19953009

BODIPY-Conjugated Xyloside Primes Fluorescent Glycosaminoglycans in the Inner Ear of Opsanus tau.

PubMed

Holman, Holly A; Tran, Vy M; Kalita, Mausam; Nguyen, Lynn N; Arungundram, Sailaja; Kuberan, Balagurunathan; Rabbitt, Richard D

2016-12-01

We report on a new xyloside conjugated to BODIPY, BX and its utility to prime fluorescent glycosaminoglycans (BX-GAGs) within the inner ear in vivo. When BX is administered directly into the endolymphatic space of the oyster toadfish (Opsanus tau) inner ear, fluorescent BX-GAGs are primed and become visible in the sensory epithelia of the semicircular canals, utricle, and saccule. Confocal and 2-photon microscopy of vestibular organs fixed 4 h following BX treatment, reveal BX-GAGs constituting glycocalyces that envelop hair cell kinocilium, nerve fibers, and capillaries. In the presence of GAG-specific enzymes, the BX-GAG signals are diminished, suggesting that chondroitin sulfates are the primary GAGs primed by BX. Results are consistent with similar click-xylosides in CHO cell lines, where the xyloside enters the Golgi and preferentially initiates chondroitin sulfate B production. Introduction of BX produces a temporary block of hair cell mechanoelectrical transduction (MET) currents in the crista, reduction in background discharge rate of afferent neurons, and a reduction in sensitivity to physiological stimulation. A six-degree-of-freedom pharmacokinetic mathematical model has been applied to interpret the time course and spatial distribution of BX and BX-GAGs. Results demonstrate a new optical approach to study GAG biology in the inner ear, for tracking synthesis and localization in real time.

Calcium oxalate stone formation in the inner ear as a result of an Slc26a4 mutation.

PubMed

Dror, Amiel A; Politi, Yael; Shahin, Hashem; Lenz, Danielle R; Dossena, Silvia; Nofziger, Charity; Fuchs, Helmut; Hrabé de Angelis, Martin; Paulmichl, Markus; Weiner, Steve; Avraham, Karen B

2010-07-09

Calcium oxalate stone formation occurs under pathological conditions and accounts for more than 80% of all types of kidney stones. In the current study, we show for the first time that calcium oxalate stones are formed in the mouse inner ear of a genetic model for hearing loss and vestibular dysfunction in humans. The vestibular system within the inner ear is dependent on extracellular tiny calcium carbonate minerals for proper function. Thousands of these biominerals, known as otoconia, are associated with the utricle and saccule sensory maculae and are vital for mechanical stimulation of the sensory hair cells. We show that a missense mutation within the Slc26a4 gene abolishes the transport activity of its encoded protein, pendrin. As a consequence, dramatic changes in mineral composition, size, and shape occur within the utricle and saccule in a differential manner. Although abnormal giant carbonate minerals reside in the utricle at all ages, in the saccule, a gradual change in mineral composition leads to a formation of calcium oxalate in adult mice. By combining imaging and spectroscopy tools, we determined the profile of mineral composition and morphology at different time points. We propose a novel mechanism for the accumulation and aggregation of oxalate crystals in the inner ear.

Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature

PubMed Central

Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

2016-01-01

An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception. PMID:26959026

Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature.

PubMed

Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

2016-03-04

An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception.

Coordinated Noninvasive Studies (CNS) Project

NASA Astrophysics Data System (ADS)

Lauter, Judith

1988-11-01

Research activities during this period include: data collection related to the interface between complex-sound production and perception, specifically, studies on speech acoustics including two experiments on voice-onset-time variability in productions by speakers of several languages, and a series on acoustical characteristics of emotional expression; data collection regarding individual differences in the effect of stimulus characteristic on relative ear advantages; continuing data analysis and new collections documenting individual differences in auditory evoked potentials, with details related to auditory-systems asymmetries preliminary tests regarding the match between behavioral measures of relative ear advantages and quantitative-electroencephalographic asymmetries observed during auditory stimulation; pilot testing using a combination of Nuclear Magnetic Resonance's (NMR) anatomical-imaging and chemical-spectral-analysis capabilities to study physiological activation in the human brain.

Metoclopramide unmasks potentially misleading contralateral suppression in patients undergoing adrenal vein sampling for primary aldosteronism.

PubMed

Rossitto, Giacomo; Miotto, Diego; Battistel, Michele; Barbiero, Giulio; Maiolino, Giuseppe; Bisogni, Valeria; Sanga, Viola; Rossi, Gian Paolo

2016-11-01

As metoclopramide stimulates aldosterone secretion, we tested its usefulness in the assessment of lateralization of primary aldosteronism by adrenal vein sampling (AVS). Prospective within-patient study in consecutive patients undergoing AVS for primary aldosteronism subtyping. We compared the diagnostic accuracy of baseline and postmetoclopramide lateralization index and relative (to cortisol) aldosterone secretion indices (RASI) for each adrenal gland with aldosterone-producing adenoma (APA) determined by the four corners criteria as the reference diagnosis. We recruited 93 consecutive patients (mean age: 52 years; women 31%). Metoclopramide increased plasma aldosterone in the inferior vena cava and in both adrenal veins. The postmetoclopramide lateralization index was accurate in identifying APA, but did not increase diagnostic accuracy over baseline lateralization index, because the RASI increased similarly in both sides. Conversely, metoclopramide raised RASI to values more than 0.90 bilaterally in non-APA patients allowing accurate identification of factitious aldosterone suppression. In contrast, RASI was 0.90 or less in 48% contralateral to the tumor in APA patients. Regression analysis showed the APA patients with persistent suppression of RASI contralaterally showed a more florid primary aldosteronism phenotype. Metoclopramide does not enhance lateralization of aldosterone excess in APA, but consistently increased the value of RASI in non-APA cases, thus unmasking potentially misleading suppression of aldosterone. Postmetoclopramide RASI may therefore allow a more precise diagnosis when AVS can be achieved only unilaterally.

Deletion of Ten-m3 Induces the Formation of Eye Dominance Domains in Mouse Visual Cortex

PubMed Central

Merlin, Sam; Horng, Sam; Marotte, Lauren R.; Sur, Mriganka; Sawatari, Atomu

2013-01-01

The visual system is characterized by precise retinotopic mapping of each eye, together with exquisitely matched binocular projections. In many species, the inputs that represent the eyes are segregated into ocular dominance columns in primary visual cortex (V1), whereas in rodents, this does not occur. Ten-m3, a member of the Ten-m/Odz/Teneurin family, regulates axonal guidance in the retinogeniculate pathway. Significantly, ipsilateral projections are expanded in the dorsal lateral geniculate nucleus and are not aligned with contralateral projections in Ten-m3 knockout (KO) mice. Here, we demonstrate the impact of altered retinogeniculate mapping on the organization and function of V1. Transneuronal tracing and c-fos immunohistochemistry demonstrate that the subcortical expansion of ipsilateral input is conveyed to V1 in Ten-m3 KOs: Ipsilateral inputs are widely distributed across V1 and are interdigitated with contralateral inputs into eye dominance domains. Segregation is confirmed by optical imaging of intrinsic signals. Single-unit recording shows ipsilateral, and contralateral inputs are mismatched at the level of single V1 neurons, and binocular stimulation leads to functional suppression of these cells. These findings indicate that the medial expansion of the binocular zone together with an interocular mismatch is sufficient to induce novel structural features, such as eye dominance domains in rodent visual cortex. PMID:22499796

Ocular vestibular evoked myogenic potentials in response to air-conducted 500 Hz short tones: Effect of stimulation procedure (monaural or binaural), age and gender.

PubMed

Versino, Maurizio; Colnaghi, Silvia; Ranzani, Marina; Alloni, Roberto; Bolis, Carlotta; Sacco, Simone; Moglia, Arrigo; Callieco, Roberto

2015-01-01

The ocular vestibular myogenic potentials (oVEMP) can be elicited by monaural air-conducted sound stimulation, and are usually recorded from the contralateral eye. In clinical setting a binaural stimulation would save time and require less effort from the subjects. We evaluated the differences between monaural and binaural stimulation, and the possible effect of age and gender on oVEMP parameters. Air-conducted oVEMP were recorded by binaural and by monaural stimulation in a group of 54 normal subjects, aged from 12 to 83 years, and in 50 vestibular patients. From each side, we measured the latency of the N1 component, and the peak-to-peak N1-P1 amplitude. For both parameters we also computed the asymmetry ratio. In normal subjects binaural stimulation produced slightly larger responses than monaural stimulation; detectability, latency and amplitude ratio were the same for the two techniques. We found no differences related to gender, and the age-induced amplitude decline was likely to be negligible.oVEMP recorded not in an acute phase of their disorder, proved to be abnormal in about 20% of the patients, and the normal or abnormal findings obtained either with monaural or with binaural stimulation were always concordant. The oVEMP obtained after binaural and monaural stimulation are very similar, and they are largely independent from age and gender.

Immediate improvement of motor function after epilepsy surgery in congenital hemiparesis.

PubMed

Pascoal, Tharick; Paglioli, Eliseu; Palmini, André; Menezes, Rafael; Staudt, Martin

2013-08-01

Hemispherectomy often leads to a loss of contralateral hand function. In some children with congenital hemiparesis, however, paretic hand function remains unchanged. An immediate improvement of hand function has never been reported. A 17-year-old boy with congenital hemiparesis and therapy-refractory seizures due to a large infarction in the territory of the middle cerebral artery underwent epilepsy surgery. Intraoperatively, electrical cortical stimulation of the affected hemisphere demonstrated preserved motor projections from the sensorimotor cortex to the (contralateral) paretic hand. A frontoparietal resection was performed, which included a complete disconnection of all motor projections originating in the sensorimotor cortex of the affected hemisphere. Surprisingly, the paretic hand showed a significant functional improvement immediately after the operation. This observation demonstrates that, in congenital hemiparesis, crossed motor projections from the affected hemisphere are not always beneficial, but can be dysfunctional, interfering with ipsilateral motor control over the paretic hand by the contralesional hemisphere. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

Responses of the ear to low frequency sounds, infrasound and wind turbines.

PubMed

Salt, Alec N; Hullar, Timothy E

2010-09-01

Infrasonic sounds are generated internally in the body (by respiration, heartbeat, coughing, etc) and by external sources, such as air conditioning systems, inside vehicles, some industrial processes and, now becoming increasingly prevalent, wind turbines. It is widely assumed that infrasound presented at an amplitude below what is audible has no influence on the ear. In this review, we consider possible ways that low frequency sounds, at levels that may or may not be heard, could influence the function of the ear. The inner ear has elaborate mechanisms to attenuate low frequency sound components before they are transmitted to the brain. The auditory portion of the ear, the cochlea, has two types of sensory cells, inner hair cells (IHC) and outer hair cells (OHC), of which the IHC are coupled to the afferent fibers that transmit "hearing" to the brain. The sensory stereocilia ("hairs") on the IHC are "fluid coupled" to mechanical stimuli, so their responses depend on stimulus velocity and their sensitivity decreases as sound frequency is lowered. In contrast, the OHC are directly coupled to mechanical stimuli, so their input remains greater than for IHC at low frequencies. At very low frequencies the OHC are stimulated by sounds at levels below those that are heard. Although the hair cells in other sensory structures such as the saccule may be tuned to infrasonic frequencies, auditory stimulus coupling to these structures is inefficient so that they are unlikely to be influenced by airborne infrasound. Structures that are involved in endolymph volume regulation are also known to be influenced by infrasound, but their sensitivity is also thought to be low. There are, however, abnormal states in which the ear becomes hypersensitive to infrasound. In most cases, the inner ear's responses to infrasound can be considered normal, but they could be associated with unfamiliar sensations or subtle changes in physiology. This raises the possibility that exposure to the infrasound component of wind turbine noise could influence the physiology of the ear. Copyright (c) 2010 Elsevier B.V. All rights reserved.

The Neural Correlates of Long-Term Carryover following Functional Electrical Stimulation for Stroke.

PubMed

Gandolla, Marta; Ward, Nick S; Molteni, Franco; Guanziroli, Eleonora; Ferrigno, Giancarlo; Pedrocchi, Alessandra

2016-01-01

Neurorehabilitation effective delivery for stroke is likely to be improved by establishing a mechanistic understanding of how to enhance adaptive plasticity. Functional electrical stimulation is effective at reducing poststroke foot drop; in some patients, the effect persists after therapy has finished with an unknown mechanism. We used fMRI to examine neural correlates of functional electrical stimulation key elements, volitional intent to move and concurrent stimulation, in a group of chronic stroke patients receiving functional electrical stimulation for foot-drop correction. Patients exhibited task-related activation in a complex network, sharing bilateral sensorimotor and supplementary motor activation with age-matched controls. We observed consistent separation of patients with and without carryover effect on the basis of brain responses. Patients who experienced the carryover effect had responses in supplementary motor area that correspond to healthy controls; the interaction between experimental factors in contralateral angular gyrus was seen only in those without carryover. We suggest that the functional electrical stimulation carryover mechanism of action is based on movement prediction and sense of agency/body ownership-the ability of a patient to plan the movement and to perceive the stimulation as a part of his/her own control loop is important for carryover effect to take place.

Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study.

PubMed

Santos, Michele Devido; Gagliardi, Rubens José; Mac-Kay, Ana Paula Machado Goyano; Boggio, Paulo Sergio; Lianza, Roberta; Fregni, Felipe

2013-01-01

Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. Prospective cohort study developed in a public university hospital. Nineteen patients with chronic aphasia received 10 transcranial direct current stimulation sessions lasting 20 minutes each on consecutive days, using a current of 2 mA. The anode was positioned over the supraorbital area and the cathode over the contralateral motor cortex. The following variables were analyzed before and after the 10 neuromodulation sessions: oral language comprehension, copying, dictation, reading, writing, naming and verbal fluency. There were no adverse effects in the study. We found statistically significant differences from before to after stimulation in relation to simple sentence comprehension (P = 0.034), naming (P = 0.041) and verbal fluency for names of animals (P = 0.038). Improved scores for performing these three tasks were seen after stimulation. We observed that excitability of the primary motor cortex through transcranial direct current stimulation was associated with effects on different aspects of language. This can contribute towards future testing in randomized controlled trials.

The RetroX auditory implant for high-frequency hearing loss.

PubMed

Garin, P; Genard, F; Galle, C; Jamart, J

2004-07-01

The objective of this study was to analyze the subjective satisfaction and measure the hearing gain provided by the RetroX (Auric GmbH, Rheine, Germany), an auditory implant of the external ear. We conducted a retrospective case review. We conducted this study at a tertiary referral center at a university hospital. We studied 10 adults with high-frequency sensori-neural hearing loss (ski-slope audiogram). The RetroX consists of an electronic unit sited in the postaural sulcus connected to a titanium tube implanted under the auricle between the sulcus and the entrance of the external auditory canal. Implanting requires only minor surgery under local anesthesia. Main outcome measures were a satisfaction questionnaire, pure-tone audiometry in quiet, speech audiometry in quiet, speech audiometry in noise, and azimuth audiometry (hearing threshold in function of sound source location within the horizontal plane at ear level). : Subjectively, all 10 patients are satisfied or even extremely satisfied with the hearing improvement provided by the RetroX. They wear the implant daily, from morning to evening. We observe a statistically significant improvement of pure-tone thresholds at 1, 2, and 4 kHz. In quiet, the speech reception threshold improves by 9 dB. Speech audiometry in noise shows that intelligibility improves by 26% for a signal-to-noise ratio of -5 dB, by 18% for a signal-to-noise ratio of 0 dB, and by 13% for a signal-to-noise ratio of +5 dB. Localization audiometry indicates that the skull masks sound contralateral to the implanted ear. Of the 10 patients, one had acoustic feedback and one presented with a granulomatous reaction to the foreign body that necessitated removing the implant. The RetroX auditory implant is a semi-implantable hearing aid without occlusion of the external auditory canal. It provides a new therapeutic alternative for managing high-frequency hearing loss.

Speech intelligibility and subjective benefit in single-sided deaf adults after cochlear implantation.

PubMed

Finke, Mareike; Strauß-Schier, Angelika; Kludt, Eugen; Büchner, Andreas; Illg, Angelika

2017-05-01

Treatment with cochlear implants (CIs) in single-sided deaf individuals started less than a decade ago. CIs can successfully reduce incapacitating tinnitus on the deaf ear and allow, so some extent, the restoration of binaural hearing. Until now, systematic evaluations of subjective CI benefit in post-lingually single-sided deaf individuals and analyses of speech intelligibility outcome for the CI in isolation have been lacking. For the prospective part of this study, the Bern Benefit in Single-Sided Deafness Questionnaire (BBSS) was administered to 48 single-sided deaf CI users to evaluate the subjectively perceived CI benefit across different listening situations. In the retrospective part, speech intelligibility outcome with the CI up to 12 month post-activation was compared between 100 single-sided deaf CI users and 125 bilaterally implanted CI users (2nd implant). The positive median ratings in the BBSS differed significantly from zero for all items suggesting that most individuals with single-sided deafness rate their CI as beneficial across listening situations. The speech perception scores in quiet and noise improved significantly over time in both groups of CI users. Speech intelligibility with the CI in isolation was significantly better in bilaterally implanted CI users (2nd implant) compared to the scores obtained from single-sided deaf CI users. Our results indicate that CI users with single-sided deafness can reach open set speech understanding with their CI in isolation, encouraging the extension of the CI indication to individuals with normal hearing on the contralateral ear. Compared to the performance reached with bilateral CI users' second implant, speech reception threshold are lower, indicating an aural preference and dominance of the normal hearing ear. The results from the BBSS propose good satisfaction with the CI across several listening situations. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of focused multipolar stimulation for cochlear implants in acutely deafened cats

NASA Astrophysics Data System (ADS)

George, Shefin S.; Wise, Andrew K.; Shivdasani, Mohit N.; Shepherd, Robert K.; Fallon, James B.

2014-12-01

Objective. The conductive nature of the fluids and tissues of the cochlea can lead to broad activation of spiral ganglion neurons using contemporary cochlear implant stimulation configurations such as monopolar (MP) stimulation. The relatively poor spatial selectivity is thought to limit implant performance, particularly in noisy environments. Several current focusing techniques have been proposed to reduce the spread of activation with the aim towards achieving improved clinical performance. Approach. The present research evaluated the efficacy of focused multipolar (FMP) stimulation, a relatively new focusing technique in the cochlea, and compared its efficacy to both MP stimulation and tripolar (TP) stimulation. The spread of neural activity across the inferior colliculus (IC), measured by recording the spatial tuning curve, was used as a measure of spatial selectivity. Adult cats (n = 6) were acutely deafened and implanted with an intracochlear electrode array before multi-unit responses were recorded across the cochleotopic gradient of the contralateral IC. Recordings were made in response to acoustic and electrical stimulation using the MP, TP and FMP configurations. Main results. FMP and TP stimulation resulted in greater spatial selectivity than MP stimulation. However, thresholds were significantly higher (p < 0.001) for FMP and TP stimulation compared to MP stimulation. There were no differences found in spatial selectivity and threshold between FMP and TP stimulation. Significance. The greater spatial selectivity of FMP and TP stimulation would be expected to result in improved clinical performance. However, further research will be required to demonstrate the efficacy of these modes of stimulation after longer durations of deafness.

Dichotic beats of mistuned consonances.

PubMed

Feeney, M P

1997-10-01

The beats of mistuned consonances (BMCs) result from the presentation of two sinusoids at frequencies slightly mistuned from a ratio of small integers. Several studies have suggested that the source of dichotic BMCs is an interaction within a binaural critical band. In one case the mechanism has been explained as an aural harmonic of the low-frequency tone (f1) creating binaural beats with the high-frequency tone (f2). The other explanation involves a binaural cross correlation between the excitation pattern of f1 and the contralateral f2--occurring within the binaural critical band centered at f2. This study examined the detection of dichotic BMCs for the octave and fifth. In one experiment with the octave, narrow-band noise centered at f2 was presented to one ear along with f1. The other ear was presented with f2. The noise was used to prevent interactions in the binaural critical band centered at f2. Dichotic BMCs were still detected under these conditions, suggesting that binaural interaction within a critical band does not explain the effect. Localization effects were also observed under this masking condition for phase reversals of tuned dichotic octave stimuli. These findings suggest a new theory of dichotic BMCs as a between-channel phase effect. The modified weighted-image model of localization [Stern and Trahiotis, in Auditory Physiology and Perception, edited by Y. Cazals, L. Demany, and K. Horner (Pergamon, Oxford, 1992), pp. 547-554] was used to provide an explanation of the between-channel mechanism.

Acoustic Transmission Characteristics of a Eustachian Tube Volitionally Opened in Two Living Subjects.

PubMed

Amoako-Tuffour, Yaw; Jufas, Nicholas; Quach, Jack; Le, Lisa; Earle, Guy; Kotiya, Akhilesh A; Bance, Manohar

2016-09-01

To assess the acoustic transmission characteristics of the Eustachian tube (ET) in living subjects in verified patent and closed ET states to facilitate the detection and quantification of ET function using acoustic measures such as sonotubometry. The two subjects in this study had no history of ear disease nor previous ear surgery and were capable of volitionally opening and closing their ET. Tympanometry and otologic examinations were used to confirm ET patent and closed states by observing tympanic membrane movement with respiration and by acoustic immitance measurements during forced respiration. A series of 500-ms long chirps containing frequencies from 100 Hz to 10 kHz were introduced into the nasal cavity during both ET states and recorded by microphones in both the contralateral naris and external auditory canal. Acoustic energy transmission through the ET across the 0.1 to 10 kHz frequency range in the closed state versus the patent state. An increase in acoustic energy transmission occurs across the frequencies of 1 to 4 kHz between the closed and patent ET states, particularly in frequencies below 2.5 kHz. Results support sonotubometry as a potential diagnostic tool for ET dysfunction. Acoustic differences between the ET states manifest as a general increase in transmitted signal amplitude. Characterizing the acoustic properties in the verified patent and closed ET states allows investigators to more reliably interpret sonotubometric tests of ET function.