Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

PubMed Central

Mehraei, Golbarg; Gallardo, Andreu Paredes; Shinn-Cunningham, Barbara G.; Dau, Torsten

2017-01-01

In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments. PMID:28159652

Preservation of auditory brainstem response thresholds after cochleostomy and titanium microactuator implantation in the lateral wall of cat scala tympani.

PubMed

Lesinski, S George; Prewitt, Jessica; Bray, Victor; Aravamudhan, Radhika; Bermeo Blanco, Oscar A; Farmer-Fedor, Brenda L; Ward, Jonette A

2014-04-01

The safety of implanting a titanium microactuator into the lateral wall of cat scala tympani was assessed by comparing preoperative and postoperative auditory brainstem response (ABR) thresholds for 1 to 3 months. The safety of directly stimulating cochlear perilymph with an implantable hearing system requires maintaining preoperative hearing levels. This cat study is an essential step in the development of the next generation of fully implantable hearing devices for humans. Following GLP surgical standards, a 1-mm cochleostomy was drilled into the lateral wall of the scala tympani, and a nonfunctioning titanium anchor/microactuator assembly was inserted in 8 cats. The scala media was damaged in the 1 cat. ABR thresholds with click and 4- and 8-kHz stimuli were measured preoperatively and compared with postoperative thresholds at 1, 2, and 3 months. Nonimplanted ear thresholds were also measured to establish statistical significance for threshold shifts (>28.4 dB). Two audiologists independently interpreted thresholds. Postoperatively, 7 cats implanted in the scala tympani demonstrated no significant ABR threshold shift for click stimulus; one shifted ABR thresholds to 4- and 8-kHz stimuli. The eighth cat, with surgical damage to the scala media, maintained stable click threshold but had a significant shift to 4- and 8-kHz stimuli. This cat study provides no evidence of worsening hearing thresholds after fenestration of the scala tympani and insertion of a titanium anchor/microactuator, provided there is no surgical trauma to the scala media and the implanted device is securely anchored in the cochleostomy. These 2 issues have been resolved in the development of a fully implantable hearing system for humans. The long-term hearing stability (combined with histologic studies) reaffirm that the microactuator is well tolerated by the cat cochlea.

Cochlear third window in the scala vestibuli: an animal model.

PubMed

Preis, Michal; Attias, Joseph; Hadar, Tuvia; Nageris, Ben I

2009-08-01

Pathologic third window has been investigated in both animals and humans, with a third window located in the vestibular apparatus, specifically, dehiscence of the superior semicircular canal, serving as the clinical model. The present study sought to examine the effect of a cochlear third window in the scala vestibuli on the auditory thresholds in fat sand rats that have a unique anatomy of the inner ear that allows for easy surgical access. The experiment included 7 healthy 6-month-old fat sand rats (a total of 10 ears). A pathologic third window was induced by drilling a hole in the bony labyrinth over the scala vestibuli, with preservation of the membranous labyrinth. Auditory brainstem responses to high- and low-frequency acoustic stimuli delivered via air and bone conduction were recorded before and after the procedure. In the preoperative auditory brainstem response recordings, air-conduction thresholds (ACTs) to clicks and tone bursts averaged 9 and 10 dB, respectively, and bone-conduction thresholds averaged 4.5 and 2.9 dB, respectively. Postfenestration ACTs averaged 41 and 42.2 dB, and bone-conduction thresholds averaged 1.1 and 4.3 dB. The change in ACT was statistically significant (p < 0.01). The presence of a cochlear third window in the scala vestibuli affects auditory thresholds by causing a decrease in sensitivity to air-conducted sound stimuli. These findings agree with the theoretical model and clinical findings.

Loud Music Exposure and Cochlear Synaptopathy in Young Adults: Isolated Auditory Brainstem Response Effects but No Perceptual Consequences.

PubMed

Grose, John H; Buss, Emily; Hall, Joseph W

2017-01-01

The purpose of this study was to test the hypothesis that listeners with frequent exposure to loud music exhibit deficits in suprathreshold auditory performance consistent with cochlear synaptopathy. Young adults with normal audiograms were recruited who either did ( n = 31) or did not ( n = 30) have a history of frequent attendance at loud music venues where the typical sound levels could be expected to result in temporary threshold shifts. A test battery was administered that comprised three sets of procedures: (a) electrophysiological tests including distortion product otoacoustic emissions, auditory brainstem responses, envelope following responses, and the acoustic change complex evoked by an interaural phase inversion; (b) psychoacoustic tests including temporal modulation detection, spectral modulation detection, and sensitivity to interaural phase; and (c) speech tests including filtered phoneme recognition and speech-in-noise recognition. The results demonstrated that a history of loud music exposure can lead to a profile of peripheral auditory function that is consistent with an interpretation of cochlear synaptopathy in humans, namely, modestly abnormal auditory brainstem response Wave I/Wave V ratios in the presence of normal distortion product otoacoustic emissions and normal audiometric thresholds. However, there were no other electrophysiological, psychophysical, or speech perception effects. The absence of any behavioral effects in suprathreshold sound processing indicated that, even if cochlear synaptopathy is a valid pathophysiological condition in humans, its perceptual sequelae are either too diffuse or too inconsequential to permit a simple differential diagnosis of hidden hearing loss.

A comparison of auditory brainstem responses across diving bird species

USGS Publications Warehouse

Crowell, Sara E.; Berlin, Alicia; Carr, Catherine E.; Olsen, Glenn H.; Therrien, Ronald E.; Yannuzzi, Sally E.; Ketten, Darlene R.

2015-01-01

There is little biological data available for diving birds because many live in hard-to-study, remote habitats. Only one species of diving bird, the black-footed penguin (Spheniscus demersus), has been studied in respect to auditory capabilities (Wever et al., Proc Natl Acad Sci USA 63:676–680, 1969). We, therefore, measured in-air auditory threshold in ten species of diving birds, using the auditory brainstem response (ABR). The average audiogram obtained for each species followed the U-shape typical of birds and many other animals. All species tested shared a common region of the greatest sensitivity, from 1000 to 3000 Hz, although audiograms differed significantly across species. Thresholds of all duck species tested were more similar to each other than to the two non-duck species tested. The red-throated loon (Gavia stellata) and northern gannet (Morus bassanus) exhibited the highest thresholds while the lowest thresholds belonged to the duck species, specifically the lesser scaup (Aythya affinis) and ruddy duck (Oxyura jamaicensis). Vocalization parameters were also measured for each species, and showed that with the exception of the common eider (Somateria mollisima), the peak frequency, i.e., frequency at the greatest intensity, of all species' vocalizations measured here fell between 1000 and 3000 Hz, matching the bandwidth of the most sensitive hearing range.

A comparison of auditory brainstem responses across diving bird species

PubMed Central

Crowell, Sara E.; Wells-Berlin, Alicia M.; Carr, Catherine E.; Olsen, Glenn H.; Therrien, Ronald E.; Yannuzzi, Sally E.; Ketten, Darlene R.

2015-01-01

There is little biological data available for diving birds because many live in hard-to-study, remote habitats. Only one species of diving bird, the black-footed penguin (Spheniscus demersus), has been studied in respect to auditory capabilities (Wever et al. 1969). We therefore measured in-air auditory threshold in ten species of diving birds, using the auditory brainstem response (ABR). The average audiogram obtained for each species followed the U-shape typical of birds and many other animals. All species tested shared a common region of greatest sensitivity, from 1000 to 3000 Hz, although audiograms differed significantly across species. Thresholds of all duck species tested were more similar to each other than to the two non-duck species tested. The red-throated loon (Gavia stellata) and northern gannet (Morus bassanus) exhibited the highest thresholds while the lowest thresholds belonged to the duck species, specifically the lesser scaup (Aythya affinis) and ruddy duck (Oxyura jamaicensis). Vocalization parameters were also measured for each species, and showed that with the exception of the common eider (Somateria mollisima), the peak frequency, i.e. frequency at the greatest intensity, of all species’ vocalizations measured here fell between 1000 and 3000 Hz, matching the bandwidth of the most sensitive hearing range. PMID:26156644

Deletion of Fmr1 Alters Function and Synaptic Inputs in the Auditory Brainstem

PubMed Central

Rotschafer, Sarah E.; Marshak, Sonya; Cramer, Karina S.

2015-01-01

Fragile X Syndrome (FXS), a neurodevelopmental disorder, is the most prevalent single-gene cause of autism spectrum disorder. Autism has been associated with impaired auditory processing, abnormalities in the auditory brainstem response (ABR), and reduced cell number and size in the auditory brainstem nuclei. FXS is characterized by elevated cortical responses to sound stimuli, with some evidence for aberrant ABRs. Here, we assessed ABRs and auditory brainstem anatomy in Fmr1 -/- mice, an animal model of FXS. We found that Fmr1 -/- mice showed elevated response thresholds to both click and tone stimuli. Amplitudes of ABR responses were reduced in Fmr1 -/- mice for early peaks of the ABR. The growth of the peak I response with sound intensity was less steep in mutants that in wild type mice. In contrast, amplitudes and response growth in peaks IV and V did not differ between these groups. We did not observe differences in peak latencies or in interpeak latencies. Cell size was reduced in Fmr1 -/- mice in the ventral cochlear nucleus (VCN) and in the medial nucleus of the trapezoid body (MNTB). We quantified levels of inhibitory and excitatory synaptic inputs in these nuclei using markers for presynaptic proteins. We measured VGAT and VGLUT immunolabeling in VCN, MNTB, and the lateral superior olive (LSO). VGAT expression in MNTB was significantly greater in the Fmr1 -/- mouse than in wild type mice. Together, these observations demonstrate that FXS affects peripheral and central aspects of hearing and alters the balance of excitation and inhibition in the auditory brainstem. PMID:25679778

[Comparison of tone burst evoked auditory brainstem responses with different filter settings for referral infants after hearing screening].

PubMed

Diao, Wen-wen; Ni, Dao-feng; Li, Feng-rong; Shang, Ying-ying

2011-03-01

Auditory brainstem responses (ABR) evoked by tone burst is an important method of hearing assessment in referral infants after hearing screening. The present study was to compare the thresholds of tone burst ABR with filter settings of 30 - 1500 Hz and 30 - 3000 Hz at each frequency, figure out the characteristics of ABR thresholds with the two filter settings and the effect of the waveform judgement, so as to select a more optimal frequency specific ABR test parameter. Thresholds with filter settings of 30 - 1500 Hz and 30 - 3000 Hz in children aged 2 - 33 months were recorded by click, tone burst ABR. A total of 18 patients (8 male/10 female), 22 ears were included. The thresholds of tone burst ABR with filter settings of 30 - 3000 Hz were higher than that with filter settings of 30 - 1500 Hz. Significant difference was detected for that at 0.5 kHz and 2.0 kHz (t values were 2.238 and 2.217, P < 0.05), no significant difference between the two filter settings was detected at the rest frequencies tone evoked ABR thresholds. The waveform of ABR with filter settings of 30 - 1500 Hz was smoother than that with filter settings of 30 - 3000 Hz at the same stimulus intensity. Response curve of the latter appeared jagged small interfering wave. The filter setting of 30 - 1500 Hz may be a more optimal parameter of frequency specific ABR to improve the accuracy of frequency specificity ABR for infants' hearing assessment.

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.

Air and Bone Conduction Frequency-specific Auditory Brainstem Response in Children with Agenesis of the External Auditory Canal

PubMed Central

Sleifer, Pricila; Didoné, Dayane Domeneghini; Keppeler, Ísis Bicca; Bueno, Claudine Devicari; Riesgo, Rudimar dos Santos

2017-01-01

Introduction  The tone-evoked auditory brainstem responses (tone-ABR) enable the differential diagnosis in the evaluation of children until 12 months of age, including those with external and/or middle ear malformations. The use of auditory stimuli with frequency specificity by air and bone conduction allows characterization of hearing profile. Objective  The objective of our study was to compare the results obtained in tone-ABR by air and bone conduction in children until 12 months, with agenesis of the external auditory canal. Method  The study was cross-sectional, observational, individual, and contemporary. We conducted the research with tone-ABR by air and bone conduction in the frequencies of 500 Hz and 2000 Hz in 32 children, 23 boys, from one to 12 months old, with agenesis of the external auditory canal. Results  The tone-ABR thresholds were significantly elevated for air conduction in the frequencies of 500 Hz and 2000 Hz, while the thresholds of bone conduction had normal values in both ears. We found no statistically significant difference between genders and ears for most of the comparisons. Conclusion  The thresholds obtained by bone conduction did not alter the thresholds in children with conductive hearing loss. However, the conductive hearing loss alter all thresholds by air conduction. The tone-ABR by bone conduction is an important tool for assessing cochlear integrity in children with agenesis of the external auditory canal under 12 months. PMID:29018492

Differential responses to acoustic damage and furosemide in auditory brainstem and otoacoustic emission measures

NASA Astrophysics Data System (ADS)

Mills, David M.

2003-02-01

Characteristics of distortion product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs) were measured in Mongolian gerbil before and after the introduction of two different auditory dysfunctions: (1) acoustic damage with a high-intensity tone, or (2) furosemide intoxication. The goal was to find emission parameters and measures that best differentiated between the two dysfunctions, e.g., at a given ABR threshold elevation. Emission input-output or ``growth'' functions were used (frequencies f1 and f2, f2/f1=1.21) with equal levels, L1=L2, and unequal levels, with L1=L2+20 dB. The best parametric choice was found to be unequal stimulus levels, and the best measure was found to be the change in the emission threshold level, Δx. The emission threshold was defined as the stimulus level required to reach a criterion emission amplitude, in this case -10 dB SPL. (The next best measure was the change in emission amplitude at high stimulus levels, specifically that measured at L1×L2=90×70 dB SPL.) For an ABR threshold shift of 20 dB or more, there was essentially no overlap in the emission threshold measures for the two conditions, sound damage or furosemide. The dividing line between the two distributions increased slowly with the change in ABR threshold, ΔABR, and was given by Δxt=0.6 ΔABR+8 dB. For a given ΔABR, if the shift in emission threshold was more than the calculated dividing line value, Δxt, the auditory dysfunction was due to acoustic damage, if less, it was due to furosemide.

Auditory brainstem responses predict auditory nerve fiber thresholds and frequency selectivity in hearing impaired chinchillas

PubMed Central

Henry, Kenneth S.; Kale, Sushrut; Scheidt, Ryan E.; Heinz, Michael G.

2011-01-01

Non-invasive auditory brainstem responses (ABRs) are commonly used to assess cochlear pathology in both clinical and research environments. In the current study, we evaluated the relationship between ABR characteristics and more direct measures of cochlear function. We recorded ABRs and auditory nerve (AN) single-unit responses in seven chinchillas with noise induced hearing loss. ABRs were recorded for 1–8 kHz tone burst stimuli both before and several weeks after four hours of exposure to a 115 dB SPL, 50 Hz band of noise with a center frequency of 2 kHz. Shifts in ABR characteristics (threshold, wave I amplitude, and wave I latency) following hearing loss were compared to AN-fiber tuning curve properties (threshold and frequency selectivity) in the same animals. As expected, noise exposure generally resulted in an increase in ABR threshold and decrease in wave I amplitude at equal SPL. Wave I amplitude at equal sensation level (SL), however, was similar before and after noise exposure. In addition, noise exposure resulted in decreases in ABR wave I latency at equal SL and, to a lesser extent, at equal SPL. The shifts in ABR characteristics were significantly related to AN-fiber tuning curve properties in the same animal at the same frequency. Larger shifts in ABR thresholds and ABR wave I amplitude at equal SPL were associated with greater AN threshold elevation. Larger reductions in ABR wave I latency at equal SL, on the other hand, were associated with greater loss of AN frequency selectivity. This result is consistent with linear systems theory, which predicts shorter time delays for broader peripheral frequency tuning. Taken together with other studies, our results affirm that ABR thresholds and wave I amplitude provide useful estimates of cochlear sensitivity. Furthermore, comparisons of ABR wave I latency to normative data at the same SL may prove useful for detecting and characterizing loss of cochlear frequency selectivity. PMID:21699970

Mitochondria-Targeted Antioxidant Mitoquinone Reduces Cisplatin-Induced Ototoxicity in Guinea Pigs.

PubMed

Tate, Alan D; Antonelli, Patrick J; Hannabass, Kyle R; Dirain, Carolyn O

2017-03-01

Objective To determine if mitoquinone (MitoQ) attenuates cisplatin-induced hearing loss in guinea pigs. Study Design Prospective and controlled animal study. Setting Academic, tertiary medical center. Subjects and Methods Guinea pigs were injected subcutaneously with either 5 mg/kg MitoQ (n = 9) or normal saline (control, n = 9) for 7 days and 1 hour before receiving a single dose of 10 mg/kg cisplatin. Auditory brainstem response thresholds were measured before MitoQ or saline administration and 3 to 4 days after cisplatin administration. Results Auditory brainstem response threshold shifts after cisplatin treatment were smaller by 28 to 47 dB in guinea pigs injected with MitoQ compared with those in the control group at all tested frequencies (4, 8, 16, and 24 kHz, P = .0002 to .04). Scanning electron microscopy of cochlear hair cells showed less outer hair cell loss and damage in the MitoQ group. Conclusion MitoQ reduced cisplatin-induced hearing loss in guinea pigs. MitoQ appears worthy of further investigation as a means of preventing cisplatin ototoxicity in humans.

Auditory evoked potentials: predicting speech therapy outcomes in children with phonological disorders.

PubMed

Leite, Renata Aparecida; Wertzner, Haydée Fiszbein; Gonçalves, Isabela Crivellaro; Magliaro, Fernanda Cristina Leite; Matas, Carla Gentile

2014-03-01

This study investigated whether neurophysiologic responses (auditory evoked potentials) differ between typically developed children and children with phonological disorders and whether these responses are modified in children with phonological disorders after speech therapy. The participants included 24 typically developing children (Control Group, mean age: eight years and ten months) and 23 children clinically diagnosed with phonological disorders (Study Group, mean age: eight years and eleven months). Additionally, 12 study group children were enrolled in speech therapy (Study Group 1), and 11 were not enrolled in speech therapy (Study Group 2). The subjects were submitted to the following procedures: conventional audiological, auditory brainstem response, auditory middle-latency response, and P300 assessments. All participants presented with normal hearing thresholds. The study group 1 subjects were reassessed after 12 speech therapy sessions, and the study group 2 subjects were reassessed 3 months after the initial assessment. Electrophysiological results were compared between the groups. Latency differences were observed between the groups (the control and study groups) regarding the auditory brainstem response and the P300 tests. Additionally, the P300 responses improved in the study group 1 children after speech therapy. The findings suggest that children with phonological disorders have impaired auditory brainstem and cortical region pathways that may benefit from speech therapy.

Hearing threshold assessment in young children with electrocochleography (EcochG) and auditory brainstem responses (ABR): experience at the University Hospital of Ferrara.

PubMed

Aimoni, C; Ciorba, A; Bovo, R; Trevisi, P; Busi, M; Martini, A

2010-10-01

Electrophysiological evaluation is a fundamental procedure for the diagnostic assessment of hearing loss during infancy; in these cases, information concerning threshold level and auditory perception is particularly useful to establish a correct hearing rehabilitation program (hearing aids and cochlear implants). Purpose of this study is to underline the role of auditory brainstem responses (ABR) and electrocochleography (EcochG) in the definition of hearing loss in a selected group of children, referred to the Audiology Department of the University Hospital of Ferrara, for a tertiary level audiological assessment. A retrospective study of the paediatric patient database at the Audiology Department of the University Hospital of Ferrara has been performed. In a period between January 2000 and December 2007, a total of 272 paediatric cases have been identified (544 ears). An EM 12 Mercury apparatus has been used for the electrophysiological threshold identification (ABR and EcochG). Recordings were carried out under general anaesthesia, in a protected enviroment. In 19 of the 272 paediatric cases selected--38 ears (7%), the results of threshold evaluation through ABR were uncertain. The Ecochg recording resulted crucial for the final diagnosis in terms of definition of the hearing threshold level, and it was then possible to ensure the better hearing rehabilitation strategy. ABR has to be considered the first choice in hearing assessment strategy, either for screening or for diagnosis in newborns as well as in non-collaborating children; ECochG still may be considered a reliable diagnostic tool. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Evaluation of peripheral auditory pathways and brainstem in obstructive sleep apnea.

PubMed

Matsumura, Erika; Matas, Carla Gentile; Magliaro, Fernanda Cristina Leite; Pedreño, Raquel Meirelles; Lorenzi-Filho, Geraldo; Sanches, Seisse Gabriela Gandolfi; Carvallo, Renata Mota Mamede

2016-11-25

Obstructive sleep apnea causes changes in normal sleep architecture, fragmenting it chronically with intermittent hypoxia, leading to serious health consequences in the long term. It is believed that the occurrence of respiratory events during sleep, such as apnea and hypopnea, can impair the transmission of nerve impulses along the auditory pathway that are highly dependent on the supply of oxygen. However, this association is not well established in the literature. To compare the evaluation of peripheral auditory pathway and brainstem among individuals with and without obstructive sleep apnea. The sample consisted of 38 adult males, mean age of 35.8 (±7.2), divided into four groups matched for age and Body Mass Index. The groups were classified based on polysomnography in: control (n=10), mild obstructive sleep apnea (n=11) moderate obstructive sleep apnea (n=8) and severe obstructive sleep apnea (n=9). All study subjects denied a history of risk for hearing loss and underwent audiometry, tympanometry, acoustic reflex and Brainstem Auditory Evoked Response. Statistical analyses were performed using three-factor ANOVA, 2-factor ANOVA, chi-square test, and Fisher's exact test. The significance level for all tests was 5%. There was no difference between the groups for hearing thresholds, tympanometry and evaluated Brainstem Auditory Evoked Response parameters. An association was observed between the presence of obstructive sleep apnea and changes in absolute latency of wave V (p=0.03). There was an association between moderate obstructive sleep apnea and change of the latency of wave V (p=0.01). The presence of obstructive sleep apnea is associated with changes in nerve conduction of acoustic stimuli in the auditory pathway in the brainstem. The increase in obstructive sleep apnea severity does not promote worsening of responses assessed by audiometry, tympanometry and Brainstem Auditory Evoked Response. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Phase stability analysis of chirp evoked auditory brainstem responses by Gabor frame operators.

PubMed

Corona-Strauss, Farah I; Delb, Wolfgang; Schick, Bernhard; Strauss, Daniel J

2009-12-01

We have recently shown that click evoked auditory brainstem responses (ABRs) can be efficiently processed using a novelty detection paradigm. Here, ABRs as a large-scale reflection of a stimulus locked neuronal group synchronization at the brainstem level are detected as novel instance-novel as compared to the spontaneous activity which does not exhibit a regular stimulus locked synchronization. In this paper we propose for the first time Gabor frame operators as an efficient feature extraction technique for ABR single sweep sequences that is in line with this paradigm. In particular, we use this decomposition technique to derive the Gabor frame phase stability (GFPS) of sweep sequences of click and chirp evoked ABRs. We show that the GFPS of chirp evoked ABRs provides a stable discrimination of the spontaneous activity from stimulations above the hearing threshold with a small number of sweeps, even at low stimulation intensities. It is concluded that the GFPS analysis represents a robust feature extraction method for ABR single sweep sequences. Further studies are necessary to evaluate the value of the presented approach for clinical applications.

Aging effects on the Binaural Interaction Component of the Auditory Brainstem Response in the Mongolian Gerbil: Effects of Interaural Time and Level Differences

PubMed Central

Laumen, Geneviève; Tollin, Daniel J.; Beutelmann, Rainer; Klump, Georg M.

2016-01-01

The effect of interaural time difference (ITD) and interaural level difference (ILD) on wave 4 of the binaural and summed monaural auditory brainstem responses (ABRs) as well as on the DN1 component of the binaural interaction component (BIC) of the ABR in young and old Mongolian gerbils (Meriones unguiculatus) was investigated. Measurements were made at a fixed sound pressure level (SPL) and a fixed level above visually detected ABR threshold to compensate for individual hearing threshold differences. In both stimulation modes (fixed SPL and fixed level above visually detected ABR threshold) an effect of ITD on the latency and the amplitude of wave 4 as well as of the BIC was observed. With increasing absolute ITD values BIC latencies were increased and amplitudes were decreased. ILD had a much smaller effect on these measures. Old animals showed a reduced amplitude of the DN1 component. This difference was due to a smaller wave 4 in the summed monaural ABRs of old animals compared to young animals whereas wave 4 in the binaural-evoked ABR showed no age-related difference. In old animals the small amplitude of the DN1 component was correlated with small binaural-evoked wave 1 and wave 3 amplitudes. This suggests that the reduced peripheral input affects central binaural processing which is reflected in the BIC. PMID:27173973

Measuring hearing in the harbor seal (Phoca vitulina): Comparison of behavioral and auditory brainstem response techniques

NASA Astrophysics Data System (ADS)

Wolski, Lawrence F.; Anderson, Rindy C.; Bowles, Ann E.; Yochem, Pamela K.

2003-01-01

Auditory brainstem response (ABR) and standard behavioral methods were compared by measuring in-air audiograms for an adult female harbor seal (Phoca vitulina). Behavioral audiograms were obtained using two techniques: the method of constant stimuli and the staircase method. Sensitivity was tested from 0.250 to 30 kHz. The seal showed good sensitivity from 6 to 12 kHz [best sensitivity 8.1 dB (re 20 μPa2.s) RMS at 8 kHz]. The staircase method yielded thresholds that were lower by 10 dB on average than the method of constant stimuli. ABRs were recorded at 2, 4, 8, 16, and 22 kHz and showed a similar best range (8-16 kHz). ABR thresholds averaged 5.7 dB higher than behavioral thresholds at 2, 4, and 8 kHz. ABRs were at least 7 dB lower at 16 kHz, and approximately 3 dB higher at 22 kHz. The better sensitivity of ABRs at higher frequencies could have reflected differences in the seal's behavior during ABR testing and/or bandwidth characteristics of test stimuli. These results agree with comparisons of ABR and behavioral methods performed in other recent studies and indicate that ABR methods represent a good alternative for estimating hearing range and sensitivity in pinnipeds, particularly when time is a critical factor and animals are untrained.

Auditory brainstem responses of CBA/J mice with neonatal conductive hearing losses and treatment with GM1 ganglioside.

PubMed

Money, M K; Pippin, G W; Weaver, K E; Kirsch, J P; Webster, D B

1995-07-01

Exogenous administration of GM1 ganglioside to CBA/J mice with a neonatal conductive hearing loss ameliorates the atrophy of spiral ganglion neurons, ventral cochlear nucleus neurons, and ventral cochlear nucleus volume. The present investigation demonstrates the extent of a conductive loss caused by atresia and tests the hypothesis that GM1 ganglioside treatment will ameliorate the conductive hearing loss. Auditory brainstem responses were recorded from four groups of seven mice each: two groups received daily subcutaneous injections of saline (one group had normal hearing; the other had a conductive hearing loss); the other two groups received daily subcutaneous injections of GM1 ganglioside (one group had normal hearing; the other had a conductive hearing loss). In mice with a conductive loss, decreases in hearing sensitivity were greatest at high frequencies. The decreases were determined by comparing mean ABR thresholds of the conductive loss mice with those of normal hearing mice. The conductive hearing loss induced in the mice in this study was similar to that seen in humans with congenital aural atresias. GM1 ganglioside treatment had no significant effect on ABR wave I thresholds or latencies in either group.

Minocycline Protection of Neomycin Induced Hearing Loss in Gerbils

PubMed Central

Robinson, Alan M.; Vujanovic, Irena; Richter, Claus-Peter

2015-01-01

This animal study was designed to determine if minocycline ameliorates cochlear damage is caused by intratympanic injection of the ototoxic aminoglycoside antibiotic neomycin. Baseline auditory-evoked brainstem responses were measured in gerbils that received 40 mM intratympanic neomycin either with 0, 1.2, or 1.5 mg/kg intraperitoneal minocycline. Four weeks later auditory-evoked brainstem responses were measured and compared to the baseline measurements. Minocycline treatments of 1.2 mg/kg and 1.5 mg/kg resulted in significantly lower threshold increases compared to 0 mg/kg, indicating protection of hearing loss between 6 kHz and 19 kHz. Cochleae were processed for histology and sectioned to allow quantification of the spiral ganglion neurons and histological evaluation of organ of Corti. Significant reduction of spiral ganglion neuron density was demonstrated in animals that did not receive minocycline, indicating that those receiving minocycline demonstrated enhanced survival of spiral ganglion neurons, enhanced survival of sensory hairs cells and spiral ganglion neurons, and reduced hearing threshold elevation correlates with minocycline treatment demonstrating that neomycin induced hearing loss can be reduced by the simultaneous application of minocycline. PMID:25950003

Development of auditory sensitivity in budgerigars (Melopsittacus undulatus)

NASA Astrophysics Data System (ADS)

Brittan-Powell, Elizabeth F.; Dooling, Robert J.

2004-06-01

Auditory feedback influences the development of vocalizations in songbirds and parrots; however, little is known about the development of hearing in these birds. The auditory brainstem response was used to track the development of auditory sensitivity in budgerigars from hatch to 6 weeks of age. Responses were first obtained from 1-week-old at high stimulation levels at frequencies at or below 2 kHz, showing that budgerigars do not hear well at hatch. Over the next week, thresholds improved markedly, and responses were obtained for almost all test frequencies throughout the range of hearing by 14 days. By 3 weeks posthatch, birds' best sensitivity shifted from 2 to 2.86 kHz, and the shape of the auditory brainstem response (ABR) audiogram became similar to that of adult budgerigars. About a week before leaving the nest, ABR audiograms of young budgerigars are very similar to those of adult birds. These data complement what is known about vocal development in budgerigars and show that hearing is fully developed by the time that vocal learning begins.

Threshold changes of ABR results in toddlers and children.

PubMed

Louza, Julia; Polterauer, Daniel; Wittlinger, Natalie; Muzaini, Hanan Al; Scheckinger, Siiri; Hempel, Martin; Schuster, Maria

2016-06-01

Auditory brainstem response (ABR) is a clinically established method to identify the hearing threshold in young children and is regularly performed after hearing screening has failed. Some studies have shown that, after the first diagnosis of hearing impairment in ABR, further development takes place in a spectrum between progression of hearing loss and, surprisingly, hearing improvement. The aim of this study is to evaluate changes over time of auditory thresholds measured by ABR among young children. For this retrospective study, 459 auditory brainstem measurements were performed and analyzed between 2010 and 2014. Hearing loss was detected and assessed according to national guidelines. 104 right ears and 101 left ears of 116 children aged between 0 and 3 years with multiple ABR measurements were included. The auditory threshold was identified using click and/or NB-chirp-stimuli in natural sleep or in general anesthesia. The frequency of differences of at least more than 10dB between the measurements was identified. In 37 (35%) measurements of right ears and 38 (38%) of left ears there was an improvement of the auditory threshold of more than 10dB; in 27 of those measurements more than 20dB improvement was found. Deterioration was seen in 12% of the right ears and 10% of the left ears. Only half of the children had stable hearing thresholds in repeated measurements. The time between the measurements was on average 5 months (0 to 31 months). Hearing threshold changes are often seen in repeated ABR measurements. Therefore multiple measurements are necessary when ABR yields abnormal. Hearing threshold changes should be taken into account for hearing aid provision. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

ASSESSMENT OF LOW-FREQUENCY HEARING WITH NARROW-BAND CHIRP EVOKED 40-HZ SINUSOIDAL AUDITORY STEADY STATE RESPONSE

PubMed Central

Wilson, Uzma S.; Kaf, Wafaa A.; Danesh, Ali A.; Lichtenhan, Jeffery T.

2016-01-01

Objective To determine the clinical utility of narrow-band chirp evoked 40-Hz sinusoidal auditory steady state responses (s-ASSR) in the assessment of low-frequency hearing in noisy participants. Design Tone bursts and narrow-band chirps were used to respectively evoke auditory brainstem responses (tb-ABR) and 40-Hz s-ASSR thresholds with the Kalman-weighted filtering technique and were compared to behavioral thresholds at 500, 2000, and 4000 Hz. A repeated measure ANOVA and post-hoc t-tests, and simple regression analyses were performed for each of the three stimulus frequencies. Study Sample Thirty young adults aged 18–25 with normal hearing participated in this study. Results When 4000 equivalent responses averages were used, the range of mean s-ASSR thresholds from 500, 2000, and 4000 Hz were 17–22 dB lower (better) than when 2000 averages were used. The range of mean tb-ABR thresholds were lower by 11–15 dB for 2000 and 4000 Hz when twice as many equivalent response averages were used, while mean tb-ABR thresholds for 500 Hz were indistinguishable regardless of additional response averaging Conclusion Narrow band chirp evoked 40-Hz s-ASSR requires a ~15 dB smaller correction factor than tb-ABR for estimating low-frequency auditory threshold in noisy participants when adequate response averaging is used. PMID:26795555

Mechanism of alpha-lipoic acid in attenuating kanamycin-induced ototoxicity☆

PubMed Central

Wang, Aimei; Hou, Ning; Bao, Dongyan; Liu, Shuangyue; Xu, Tao

2012-01-01

In view of the theory that alpha-lipoic acid effectively prevents cochlear cells from injury caused by various factors such as cisplatin and noise, this study examined whether alpha-lipoic acid can prevent kanamycin-induced ototoxicity. To this end, healthy BALB/c mice were injected subcutaneously with alpha-lipoic acid and kanamycin for 14 days. Auditory brainstem response test showed that increased auditory brainstem response threshold shifts caused by kanamycin were significantly inhibited. Immunohistochemical staining and western blot analysis showed that the expression of phosphorylated p38 mitogen-activated protein kinase and phosphorylated c-Jun N-terminal kinase in mouse cochlea was significantly decreased. The experimental findings suggest that phosphorylated p38 and phosphorylated c-Jun N-terminal kinase mediated kanamycin-induced ototoxic injury in BALB/c mice. Alpha-lipoic acid effectively attenuated kanamycin ototoxicity by inhibiting the kanamycin-induced high expression of phosphorylated p38 and phosphorylated c-Jun N-terminal kinase. PMID:25317129

A kernel-based novelty detection scheme for the ultra-fast detection of chirp evoked Auditory Brainstem Responses.

PubMed

Corona-Strauss, Farah I; Delb, Wolfgang; Schick, Bernhard; Strauss, Daniel J

2010-01-01

Auditory Brainstem Responses (ABRs) are used as objective method for diagnostics and quantification of hearing loss. Many methods for automatic recognition of ABRs have been developed, but none of them include the individual measurement setup in the analysis. The purpose of this work was to design a fast recognition scheme for chirp-evoked ABRs that is adjusted to the individual measurement condition using spontaneous electroencephalographic activity (SA). For the classification, the kernel-based novelty detection scheme used features based on the inter-sweep instantaneous phase synchronization as well as energy and entropy relations in the time-frequency domain. This method provided SA discrimination from stimulations above the hearing threshold with a minimum number of sweeps, i.e., 200 individual responses. It is concluded that the proposed paradigm, processing procedures and stimulation techniques improve the detection of ABRs in terms of the degree of objectivity, i.e., automation of procedure, and measurement time.

Aging effects on the binaural interaction component of the auditory brainstem response in the Mongolian gerbil: Effects of interaural time and level differences.

PubMed

Laumen, Geneviève; Tollin, Daniel J; Beutelmann, Rainer; Klump, Georg M

2016-07-01

The effect of interaural time difference (ITD) and interaural level difference (ILD) on wave 4 of the binaural and summed monaural auditory brainstem responses (ABRs) as well as on the DN1 component of the binaural interaction component (BIC) of the ABR in young and old Mongolian gerbils (Meriones unguiculatus) was investigated. Measurements were made at a fixed sound pressure level (SPL) and a fixed level above visually detected ABR threshold to compensate for individual hearing threshold differences. In both stimulation modes (fixed SPL and fixed level above visually detected ABR threshold) an effect of ITD on the latency and the amplitude of wave 4 as well as of the BIC was observed. With increasing absolute ITD values BIC latencies were increased and amplitudes were decreased. ILD had a much smaller effect on these measures. Old animals showed a reduced amplitude of the DN1 component. This difference was due to a smaller wave 4 in the summed monaural ABRs of old animals compared to young animals whereas wave 4 in the binaural-evoked ABR showed no age-related difference. In old animals the small amplitude of the DN1 component was correlated with small binaural-evoked wave 1 and wave 3 amplitudes. This suggests that the reduced peripheral input affects central binaural processing which is reflected in the BIC. Copyright © 2016 Elsevier B.V. All rights reserved.

The direct pathway from the brainstem reticular formation to the cerebral cortex in the ascending reticular activating system: A diffusion tensor imaging study.

PubMed

Jang, Sung Ho; Kwon, Hyeok Gyu

2015-10-08

Precise evaluation of the ascending reticular activating system (ARAS) is important for diagnosis, prediction of prognosis, and management of patients with disorders of impaired consciousness. In the current study, we attempted to reconstruct the direct neural pathway between the brainstem reticular formation (RF) and the cerebral cortex in normal subjects, using diffusion tensor imaging (DTI). Forty-one healthy subjects were recruited for this study. DTIs were performed using a sensitivity-encoding head coil at 1.5Tesla with FMRIB Software Library. For connectivity of the brainstem RF, we used two regions of interest (ROIs) for the brainstem RF (seed ROI) and the thalamus and hypothalamus (exclusion ROI). Connectivity was defined as the incidence of connection between the brainstem RF and target brain regions at the threshold of 5 and 50 streamlines. Regarding the thresholds of 5 and 50, the brainstem RF showed high connectivity to the lateral prefrontal cortex (lPFC, 67.1% and 20.7%) and ventromedial prefrontal cortex (vmPFC, 50.0% and 18.3%), respectively. In contrast, the brainstem RF showed low connectivity to the primary motor cortex (31.7% and 3.7%), premotor cortex (24.4% and 3.7%), primary somatosensory cortex (23.2% and 2.4%), orbitofrontal cortex (17.1% and 7.3%), and posterior parietal cortex (12.2% and 0%), respectively. The brainstem RF was mainly connected to the prefrontal cortex, particularly lPFC and vmPFC. We believe that the methodology and results of this study would be useful to clinicians involved in the care of patients with impaired consciousness and researchers in studies of the ARAS. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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.

Audiological and electrophysiological assessment of professional pop/rock musicians.

PubMed

Samelli, Alessandra G; Matas, Carla G; Carvallo, Renata M M; Gomes, Raquel F; de Beija, Carolina S; Magliaro, Fernanda C L; Rabelo, Camila M

2012-01-01

In the present study, we evaluated peripheral and central auditory pathways in professional musicians (with and without hearing loss) compared to non-musicians. The goal was to verify if music exposure could affect auditory pathways as a whole. This is a prospective study that compared the results obtained between three groups (musicians with and without hearing loss and non-musicians). Thirty-two male individuals participated and they were assessed by: Immittance measurements, pure-tone air conduction thresholds at all frequencies from 0.25 to 20 kHz, Transient Evoked Otoacoustic Emissions, Auditory Brainstem Response (ABR), and Cognitive Potential. The musicians showed worse hearing thresholds in both conventional and high frequency audiometry when compared to the non-musicians; the mean amplitude of Transient Evoked Otoacoustic Emissions was smaller in the musicians group, but the mean latencies of Auditory Brainstem Response and Cognitive Potential were diminished in the musicians when compared to the non-musicians. Our findings suggest that the population of musicians is at risk for developing music-induced hearing loss. However, the electrophysiological evaluation showed that latency waves of ABR and P300 were diminished in musicians, which may suggest that the auditory training to which these musicians are exposed acts as a facilitator of the acoustic signal transmission to the cortex.

Comparison of distortion product otoacoustic emissions with auditory brain-stem response for clinical use in neonatal intensive care unit.

PubMed

Ochi, A; Yasuhara, A; Kobayashi, Y

1998-11-01

This study compares the clinical usefulness of distortion product otoacoustic emissions (DPOAEs) with the auditory brain-stem response (ABR) for neonates in the neonatal intensive care unit for the evaluation of hearing impairment. Both DPOAEs and ABR were performed on 36 neonates (67 ears) on the same day. We defined neonates as having normal hearing when the thresholds of wave V of ABR were < or =45 dB hearing level. (1) We could not obtain DPOAEs at f2 = 977 Hz in neonates with normal hearing because of high noise floors. DPOAE recording time was 36 min shorter than that of ABR. (2) We defined as normal DPOAEs, the number of frequencies which showed the DPgram-noise floor > or =4 dB was > or =4 at 6 f2 frequencies, from 1416 Hz to 7959 Hz. (3) Normal thresholds of ABR and normal DPOAEs showed the same percentages, i.e. 68.7%, but the percentage of different results between ABR and DPOAEs was 6.0%. Our study indicates that DPOAEs represent a simple procedure, which can be easily performed in the NICU to obtain reliable results in high-risk neonates. Results obtained by DPOAEs were comparable to those obtained by the more complex procedure of ABR.

Speech-in-Noise Tests and Supra-threshold Auditory Evoked Potentials as Metrics for Noise Damage and Clinical Trial Outcome Measures.

PubMed

Le Prell, Colleen G; Brungart, Douglas S

2016-09-01

In humans, the accepted clinical standards for detecting hearing loss are the behavioral audiogram, based on the absolute detection threshold of pure-tones, and the threshold auditory brainstem response (ABR). The audiogram and the threshold ABR are reliable and sensitive measures of hearing thresholds in human listeners. However, recent results from noise-exposed animals demonstrate that noise exposure can cause substantial neurodegeneration in the peripheral auditory system without degrading pure-tone audiometric thresholds. It has been suggested that clinical measures of auditory performance conducted with stimuli presented above the detection threshold may be more sensitive than the behavioral audiogram in detecting early-stage noise-induced hearing loss in listeners with audiometric thresholds within normal limits. Supra-threshold speech-in-noise testing and supra-threshold ABR responses are reviewed here, given that they may be useful supplements to the behavioral audiogram for assessment of possible neurodegeneration in noise-exposed listeners. Supra-threshold tests may be useful for assessing the effects of noise on the human inner ear, and the effectiveness of interventions designed to prevent noise trauma. The current state of the science does not necessarily allow us to define a single set of best practice protocols. Nonetheless, we encourage investigators to incorporate these metrics into test batteries when feasible, with an effort to standardize procedures to the greatest extent possible as new reports emerge.

Systemic immunity influences hearing preservation in cochlear implantation.

PubMed

Souter, Melanie; Eastwood, Hayden; Marovic, Paul; Kel, Gordana; Wongprasartsuk, Sarin; Ryan, Allen F; O'Leary, Stephen John

2012-06-01

To determine whether a systemic immune response influences hearing thresholds and tissue response after cochlear implantation of hearing guinea pigs. Guinea pigs were inoculated with sterile antigen (Keyhole limpet hemocyanin) 3 weeks before cochlear implantation. Pure-tone auditory brainstem response thresholds were performed before implantation and 1 and 4 weeks later. Dexamethasone phosphate 20% was adsorbed onto a hyaluronic acid carboxymethylcellulose sponge and was applied to the round window for 30 minutes before electrode insertion. Normal saline was used for controls. Cochlear histology was performed at 4 weeks after implantation to assess the tissue response to implantation. To control for the effect of keyhole limpet hemocyanin priming, a group of unprimed animals underwent cochlear implantation with a saline-soaked pledget applied to the round window. Keyhole limpet hemocyanin priming had no significant detrimental effect on thresholds without implantation. Thresholds were elevated after implantation across all frequencies tested (2-32 kHz) in primed animals but only at higher frequencies (4-32 kHz) in unprimed controls. In primed animals, dexamethasone treatment significantly reduced threshold shifts at 2 and 8 kHz. Keyhole limpet hemocyanin led to the more frequent observation of lymphocytes in the tissue response to the implant. Systemic immune activation at the time of cochlear implantation broadened the range of frequencies experiencing elevated thresholds after implantation. Local dexamethasone provides partial protection against this hearing loss, but the degree and extent of protection are less compared to previous studies with unprimed animals.

Auditory brainstem responses in the Eastern Screech Owl: An estimate of auditory thresholds

USGS Publications Warehouse

Brittan-Powell, E.F.; Lohr, B.; Hahn, D.C.; Dooling, R.J.

2005-01-01

The auditory brainstem response (ABR), a measure of neural synchrony, was used to estimate auditory sensitivity in the eastern screech owl (Megascops asio). The typical screech owl ABR waveform showed two to three prominent peaks occurring within 5 ms of stimulus onset. As sound pressure levels increased, the ABR peak amplitude increased and latency decreased. With an increasing stimulus presentation rate, ABR peak amplitude decreased and latency increased. Generally, changes in the ABR waveform to stimulus intensity and repetition rate are consistent with the pattern found in several avian families. The ABR audiogram shows that screech owls hear best between 1.5 and 6.4 kHz with the most acute sensitivity between 4?5.7 kHz. The shape of the average screech owl ABR audiogram is similar to the shape of the behaviorally measured audiogram of the barn owl, except at the highest frequencies. Our data also show differences in overall auditory sensitivity between the color morphs of screech owls.

Specialization for underwater hearing by the tympanic middle ear of the turtle, Trachemys scripta elegans

PubMed Central

Christensen-Dalsgaard, Jakob; Brandt, Christian; Willis, Katie L.; Christensen, Christian Bech; Ketten, Darlene; Edds-Walton, Peggy; Fay, Richard R.; Madsen, Peter T.; Carr, Catherine E.

2012-01-01

Turtles, like other amphibious animals, face a trade-off between terrestrial and aquatic hearing. We used laser vibrometry and auditory brainstem responses to measure their sensitivity to vibration stimuli and to airborne versus underwater sound. Turtles are most sensitive to sound underwater, and their sensitivity depends on the large middle ear, which has a compliant tympanic disc attached to the columella. Behind the disc, the middle ear is a large air-filled cavity with a volume of approximately 0.5 ml and a resonance frequency of approximately 500 Hz underwater. Laser vibrometry measurements underwater showed peak vibrations at 500–600 Hz with a maximum of 300 µm s−1 Pa−1, approximately 100 times more than the surrounding water. In air, the auditory brainstem response audiogram showed a best sensitivity to sound of 300–500 Hz. Audiograms before and after removing the skin covering reveal that the cartilaginous tympanic disc shows unchanged sensitivity, indicating that the tympanic disc, and not the overlying skin, is the key sound receiver. If air and water thresholds are compared in terms of sound intensity, thresholds in water are approximately 20–30 dB lower than in air. Therefore, this tympanic ear is specialized for underwater hearing, most probably because sound-induced pulsations of the air in the middle ear cavity drive the tympanic disc. PMID:22438494

Specialization for underwater hearing by the tympanic middle ear of the turtle, Trachemys scripta elegans.

PubMed

Christensen-Dalsgaard, Jakob; Brandt, Christian; Willis, Katie L; Christensen, Christian Bech; Ketten, Darlene; Edds-Walton, Peggy; Fay, Richard R; Madsen, Peter T; Carr, Catherine E

2012-07-22

Turtles, like other amphibious animals, face a trade-off between terrestrial and aquatic hearing. We used laser vibrometry and auditory brainstem responses to measure their sensitivity to vibration stimuli and to airborne versus underwater sound. Turtles are most sensitive to sound underwater, and their sensitivity depends on the large middle ear, which has a compliant tympanic disc attached to the columella. Behind the disc, the middle ear is a large air-filled cavity with a volume of approximately 0.5 ml and a resonance frequency of approximately 500 Hz underwater. Laser vibrometry measurements underwater showed peak vibrations at 500-600 Hz with a maximum of 300 µm s(-1) Pa(-1), approximately 100 times more than the surrounding water. In air, the auditory brainstem response audiogram showed a best sensitivity to sound of 300-500 Hz. Audiograms before and after removing the skin covering reveal that the cartilaginous tympanic disc shows unchanged sensitivity, indicating that the tympanic disc, and not the overlying skin, is the key sound receiver. If air and water thresholds are compared in terms of sound intensity, thresholds in water are approximately 20-30 dB lower than in air. Therefore, this tympanic ear is specialized for underwater hearing, most probably because sound-induced pulsations of the air in the middle ear cavity drive the tympanic disc.

Rapid measurement of auditory filter shape in mice using the auditory brainstem response and notched noise.

PubMed

Lina, Ioan A; Lauer, Amanda M

2013-04-01

The notched noise method is an effective procedure for measuring frequency resolution and auditory filter shapes in both human and animal models of hearing. Briefly, auditory filter shape and bandwidth estimates are derived from masked thresholds for tones presented in noise containing widening spectral notches. As the spectral notch widens, increasingly less of the noise falls within the auditory filter and the tone becomes more detectible until the notch width exceeds the filter bandwidth. Behavioral procedures have been used for the derivation of notched noise auditory filter shapes in mice; however, the time and effort needed to train and test animals on these tasks renders a constraint on the widespread application of this testing method. As an alternative procedure, we combined relatively non-invasive auditory brainstem response (ABR) measurements and the notched noise method to estimate auditory filters in normal-hearing mice at center frequencies of 8, 11.2, and 16 kHz. A complete set of simultaneous masked thresholds for a particular tone frequency were obtained in about an hour. ABR-derived filter bandwidths broadened with increasing frequency, consistent with previous studies. The ABR notched noise procedure provides a fast alternative to estimating frequency selectivity in mice that is well-suited to high through-put or time-sensitive screening. Copyright © 2013 Elsevier B.V. All rights reserved.

Auditory-steady-state response reliability in the audiological diagnosis after neonatal hearing screening.

PubMed

Núñez-Batalla, Faustino; Noriega-Iglesias, Sabel; Guntín-García, Maite; Carro-Fernández, Pilar; Llorente-Pendás, José Luis

2016-01-01

Conventional audiometry is the gold standard for quantifying and describing hearing loss. Alternative methods become necessary to assess subjects who are too young to respond reliably. Auditory evoked potentials constitute the most widely used method for determining hearing thresholds objectively; however, this stimulus is not frequency specific. The advent of the auditory steady-state response (ASSR) leads to more specific threshold determination. The current study describes and compares ASSR, auditory brainstem response (ABR) and conventional behavioural tone audiometry thresholds in a group of infants with various degrees of hearing loss. A comparison was made between ASSR, ABR and behavioural hearing thresholds in 35 infants detected in the neonatal hearing screening program. Mean difference scores (±SD) between ABR and high frequency ABR thresholds were 11.2 dB (±13) and 10.2 dB (±11). Pearson correlations between the ASSR and audiometry thresholds were 0.80 and 0.91 (500Hz); 0.84 and 0.82 (1000Hz); 0.85 and 0.84 (2000Hz); and 0.83 and 0.82 (4000Hz). The ASSR technique is a valuable extension of the clinical test battery for hearing-impaired children. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Auditory brainstem evoked responses and temperature monitoring during pediatric cardiopulmonary bypass.

PubMed

Rodriguez, R A; Edmonds, H L; Auden, S M; Austin, E H

1999-09-01

To examine the effects of temperature on auditory brainstem responses (ABRs) in infants during hypothermic cardiopulmonary bypass for total circulatory arrest (TCA). The relationship between ABRs (as a surrogate measure of core-brain temperature) and body temperature as measured at several temperature monitoring sites was determined. In a prospective, observational study, ABRs were recorded non-invasively at normothermia and at every 1 or 2 degrees C change in ear-canal temperature during cooling and rewarming in 15 infants (ages: 2 days to 14 months) that required TCA. The ABR latencies and amplitudes and the lowest temperatures at which an ABR was identified (the threshold) were measured during both cooling and rewarming. Temperatures from four standard temperature monitoring sites were simultaneously recorded. The latencies of ABRs increased and amplitudes decreased with cooling (P < 0.01), but rewarming reversed these effects. The ABR threshold temperature as related to each monitoring site (ear-canal, nasopharynx, esophagus and bladder) was respectively determined as 23 +/- 2.2 degrees C, 20.8 +/- 1.7 degrees C, 14.6 +/- 3.4 degrees C, and 21.5 +/- 3.8 degrees C during cooling and 21.8 +/- 1.6 degrees C, 22.4 +/- 2.0 degrees C, 27.6 +/- 3.6 degrees C, and 23.0 +/- 2.4 degrees C during rewarming. The rewarming latencies were shorter and Q10 latencies smaller than the corresponding cooling values (P < 0.01). Esophageal and bladder sites were more susceptible to temperature variations as compared with the ear-canal and nasopharynx. No temperature site reliably predicted an electrophysiological threshold. A faster latency recovery during rewarming suggests that body temperature monitoring underestimates the effects of rewarming in the core-brain. ABRs may be helpful to monitor the effects of cooling and rewarming on the core-brain during pediatric cardiopulmonary bypass.

Four cases of acoustic neuromas with normal hearing.

PubMed

Valente, M; Peterein, J; Goebel, J; Neely, J G

1995-05-01

In 95 percent of the cases, patients with acoustic neuromas will have some magnitude of hearing loss in the affected ear. This paper reports on four patients who had acoustic neuromas and normal hearing. Results from the case history, audiometric evaluation, auditory brainstem response (ABR), electroneurography (ENOG), and vestibular evaluation are reported for each patient. For all patients, the presence of unilateral tinnitus was the most common complaint. Audiologically, elevated or absent acoustic reflex thresholds and abnormal ABR findings were the most powerful diagnostic tools.

Auditory Brainstem Responses in Autism: Brainstem Dysfunction or Peripheral Hearing Loss?

ERIC Educational Resources Information Center

Klin, Ami

1993-01-01

A review of 11 studies of auditory brainstem response (ABR) in individuals with autism concludes that the ABR data are only suggestive (rather than supportive) of brainstem involvement in autism. The presence of peripheral hearing impairment was observed in some of the autistic individuals. (Author/DB)

Gap prepulse inhibition and auditory brainstem-evoked potentials as objective measures for tinnitus in guinea pigs

PubMed Central

Dehmel, Susanne; Eisinger, Daniel; Shore, Susan E.

2012-01-01

Tinnitus or ringing of the ears is a subjective phantom sensation necessitating behavioral models that objectively demonstrate the existence and quality of the tinnitus sensation. The gap detection test uses the acoustic startle response elicited by loud noise pulses and its gating or suppression by preceding sub-startling prepulses. Gaps in noise bands serve as prepulses, assuming that ongoing tinnitus masks the gap and results in impaired gap detection. This test has shown its reliability in rats, mice, and gerbils. No data exists for the guinea pig so far, although gap detection is similar across mammals and the acoustic startle response is a well-established tool in guinea pig studies of psychiatric disorders and in pharmacological studies. Here we investigated the startle behavior and prepulse inhibition (PPI) of the guinea pig and showed that guinea pigs have a reliable startle response that can be suppressed by 15 ms gaps embedded in narrow noise bands preceding the startle noise pulse. After recovery of auditory brainstem response (ABR) thresholds from a unilateral noise over-exposure centered at 7 kHz, guinea pigs showed diminished gap-induced reduction of the startle response in frequency bands between 8 and 18 kHz. This suggests the development of tinnitus in frequency regions that showed a temporary threshold shift (TTS) after noise over-exposure. Changes in discharge rate and synchrony, two neuronal correlates of tinnitus, should be reflected in altered ABR waveforms, which would be useful to objectively detect tinnitus and its localization to auditory brainstem structures. Therefore, we analyzed latencies and amplitudes of the first five ABR waves at suprathreshold sound intensities and correlated ABR abnormalities with the results of the behavioral tinnitus testing. Early ABR wave amplitudes up to N3 were increased for animals with tinnitus possibly stemming from hyperactivity and hypersynchrony underlying the tinnitus percept. Animals that did not develop tinnitus after noise exposure showed the opposite effect, a decrease in wave amplitudes for the later waves P4–P5. Changes in latencies were only observed in tinnitus animals, which showed increased latencies. Thus, tinnitus-induced changes in the discharge activity of the auditory nerve and central auditory nuclei are represented in the ABR. PMID:22666193

Effect of middle ear fluid on sound transmission and auditory brainstem response in guinea pigs.

PubMed

Guan, Xiying; Gan, Rong Z

2011-07-01

Combined measurements of middle ear transfer function and auditory brainstem response (ABR) in live guinea pigs with middle ear effusion (MEE) are reported in this paper. The MEE model was created by injecting saline into the middle ear cavity. Vibrations of the tympanic membrane (TM), the tip of the incus, and the round window membrane (RWM) were measured with a laser vibrometer at frequencies of 0.2-40 kHz when the middle ear fluid increased from 0 to 0.2 ml (i.e., full fill of the cavity). The click and pure tone ABRs were recorded as the middle ear fluid increased. Fluid introduction reduced mobility of the TM, incus and RWM mainly at high frequencies (f > 1 kHz). The magnitude of this reduction was related to the volume of fluid. The displacement transmission ratio of the TM to incus varied with frequency and fluid level. The volume displacement ratio of the oval window to round window was approximately 1.0 over most frequencies. Elevation of ABR thresholds and prolongation of ABR latencies were observed as fluid level increased. Reduction of TM displacement correlated well with elevation of ABR threshold at 0.5-8 kHz. Alterations in the ratio of ossicular displacements before and after fluid induction are consistent with fluid-induced changes in complex ossicular motions. Copyright © 2011 Elsevier B.V. All rights reserved.

Control of Phasic Firing by a Background Leak Current in Avian Forebrain Auditory Neurons

PubMed Central

Dagostin, André A.; Lovell, Peter V.; Hilscher, Markus M.; Mello, Claudio V.; Leão, Ricardo M.

2015-01-01

Central neurons express a variety of neuronal types and ion channels that promote firing heterogeneity among their distinct neuronal populations. Action potential (AP) phasic firing, produced by low-threshold voltage-activated potassium currents (VAKCs), is commonly observed in mammalian brainstem neurons involved in the processing of temporal properties of the acoustic information. The avian caudomedial nidopallium (NCM) is an auditory area analogous to portions of the mammalian auditory cortex that is involved in the perceptual discrimination and memorization of birdsong and shows complex responses to auditory stimuli We performed in vitro whole-cell patch-clamp recordings in brain slices from adult zebra finches (Taeniopygia guttata) and observed that half of NCM neurons fire APs phasically in response to membrane depolarizations, while the rest fire transiently or tonically. Phasic neurons fired APs faster and with more temporal precision than tonic and transient neurons. These neurons had similar membrane resting potentials, but phasic neurons had lower membrane input resistance and time constant. Surprisingly phasic neurons did not express low-threshold VAKCs, which curtailed firing in phasic mammalian brainstem neurons, having similar VAKCs to other NCM neurons. The phasic firing was determined not by VAKCs, but by the potassium background leak conductances, which was more prominently expressed in phasic neurons, a result corroborated by pharmacological, dynamic-clamp, and modeling experiments. These results reveal a new role for leak currents in generating firing diversity in central neurons. PMID:26696830

Identifying cochlear implant channels with poor electrode-neuron interface: electrically-evoked auditory brainstem responses measured with the partial tripolar configuration

PubMed Central

Bierer, Julie Arenberg; Faulkner, Kathleen F.; Tremblay, Kelly L.

2011-01-01

Objectives The goal of this study was to compare cochlear implant behavioral measures and electrically-evoked auditory brainstem responses (EABRs) obtained with a spatially focused electrode configuration. It has been shown previously that channels with high thresholds, when measured with the tripolar configuration, exhibit relatively broad psychophysical tuning curves (Bierer and Faulkner, 2010). The elevated threshold and degraded spatial/spectral selectivity of such channels are consistent with a poor electrode-neuron interface, such as suboptimal electrode placement or reduced nerve survival. However, the psychophysical methods required to obtain these data are time intensive and may not be practical during a clinical mapping procedure, especially for young children. Here we have extended the previous investigation to determine if a physiological approach could provide a similar assessment of channel functionality. We hypothesized that, in accordance with the perceptual measures, higher EABR thresholds would correlate with steeper EABR amplitude growth functions, reflecting a degraded electrode-neuron interface. Design Data were collected from six cochlear implant listeners implanted with the HiRes 90k cochlear implant (Advanced Bionics). Single-channel thresholds and most comfortable listening levels were obtained for stimuli that varied in presumed electrical field size by using the partial tripolar configuration, for which a fraction of current (σ) from a center active electrode returns through two neighboring electrodes and the remainder through a distant indifferent electrode. EABRs were obtained in each subject for the two channels having the highest and lowest tripolar (σ=1 or 0.9) behavioral threshold. Evoked potentials were measured with both the monopolar (σ=0) and a more focused partial tripolar (σ ≥ 0.50) configuration. Results Consistent with previous studies, EABR thresholds were highly and positively correlated with behavioral thresholds obtained with both the monopolar and partial tripolar configurations. The Wave V amplitude growth functions with increasing stimulus level showed the predicted effect of shallower growth for the partial tripolar than for the monopolar configuration, but this was observed only for the low threshold channel. In contrast, high-threshold channels showed the opposite effect; steeper growth functions were seen for the partial tripolar configuration. Conclusions These results suggest that behavioral thresholds or EABRs measured with a restricted stimulus can be used to identify potentially impaired cochlear implant channels. Channels having high thresholds and steep growth functions would likely not activate the appropriate spatially restricted region of the cochlea, leading to suboptimal perception. As a clinical tool, quick identification of impaired channels could lead to patient-specific mapping strategies and result in improved speech and music perception. PMID:21178633

Auditory effects of aircraft noise on people living near an airport.

PubMed

Chen, T J; Chen, S S; Hsieh, P Y; Chiang, H C

1997-01-01

Two groups of randomly chosen individuals who lived in two communities located different distances from the airport were studied. We monitored audiometry and brainstem auditory-evoked potentials to evaluate cochlear and retrocochlear functions in the individuals studied. The results of audiometry measurements indicated that hearing ability was reduced significantly in individuals who lived near the airport and who were exposed frequently to aircraft noise. Values of pure-tone average, high pure-tone average, and threshold at 4 kHz were all higher in individuals who lived near the airport, compared with those who lived farther away. With respect to brainstem auditory-evoked potentials, latencies between the two groups were not consistently different; however, the abnormality rate of such potentials was significantly higher in volunteers who lived near the airport, compared with less-exposed counterparts. In addition, a positive correlation was found between brainstem auditory-evoked potential latency and behavioral hearing threshold of high-frequency tone in exposed volunteers. We not only confirmed that damage to the peripheral cochlear organs occurred in individuals exposed frequently to aircraft noise, but we demonstrated involvement of the central auditory pathway.

The human auditory brainstem response to running speech reveals a subcortical mechanism for selective attention.

PubMed

Forte, Antonio Elia; Etard, Octave; Reichenbach, Tobias

2017-10-10

Humans excel at selectively listening to a target speaker in background noise such as competing voices. While the encoding of speech in the auditory cortex is modulated by selective attention, it remains debated whether such modulation occurs already in subcortical auditory structures. Investigating the contribution of the human brainstem to attention has, in particular, been hindered by the tiny amplitude of the brainstem response. Its measurement normally requires a large number of repetitions of the same short sound stimuli, which may lead to a loss of attention and to neural adaptation. Here we develop a mathematical method to measure the auditory brainstem response to running speech, an acoustic stimulus that does not repeat and that has a high ecological validity. We employ this method to assess the brainstem's activity when a subject listens to one of two competing speakers, and show that the brainstem response is consistently modulated by attention.

The dissimilar time course of temporary threshold shifts and reduction of inhibition in the inferior colliculus following intense sound exposure.

PubMed

Heeringa, A N; van Dijk, P

2014-06-01

Excessive noise exposure is known to produce an auditory threshold shift, which can be permanent or transient in nature. Recent studies showed that noise-induced temporary threshold shifts are associated with loss of synaptic connections to the inner hair cells and with cochlear nerve degeneration, which is reflected in a decreased amplitude of wave I of the auditory brainstem response (ABR). This suggests that, despite normal auditory thresholds, central auditory processing may be abnormal. We recorded changes in central auditory processing following a sound-induced temporary threshold shift. Anesthetized guinea pigs were exposed for 1 h to a pure tone of 11 kHz (124 dB sound pressure level). Hearing thresholds, amplitudes of ABR waves I and IV, and spontaneous and tone-evoked firing rates in the inferior colliculus (IC) were assessed immediately, one week, two weeks, and four weeks post exposure. Hearing thresholds were elevated immediately following overexposure, but recovered within one week. The amplitude of the ABR wave I was decreased in all sound-exposed animals for all test periods. In contrast, the ABR wave IV amplitude was only decreased immediately after overexposure and recovered within a week. The proportion of IC units that show inhibitory responses to pure tones decreased substantially up to two weeks after overexposure, especially when stimulated with high frequencies. The proportion of excitatory responses to low frequencies was increased. Spontaneous activity was unaffected by the overexposure. Despite rapid normalization of auditory thresholds, our results suggest an increased central gain following sound exposure and an abnormal balance between excitatory and inhibitory responses in the midbrain up to two weeks after overexposure. These findings may be associated with hyperacusis after a sound-induced temporary threshold shift. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Brainstem Encoding of Aided Speech in Hearing Aid Users with Cochlear Dead Region(s).

PubMed

Hassaan, Mohammad Ramadan; Ibraheem, Ola Abdallah; Galhom, Dalia Helal

2016-07-01

Neural encoding of speech begins with the analysis of the signal as a whole broken down into its sinusoidal components in the cochlea, which has to be conserved up to the higher auditory centers. Some of these components target the dead regions of the cochlea causing little or no excitation. Measuring aided speech-evoked auditory brainstem response elicited by speech stimuli with different spectral maxima can give insight into the brainstem encoding of aided speech with spectral maxima at these dead regions. This research aims to study the impact of dead regions of the cochlea on speech processing at the brainstem level after a long period of hearing aid use. This study comprised 30 ears without dead regions and 46 ears with dead regions at low, mid, or high frequencies. For all ears, we measured the aided speech-evoked auditory brainstem response using speech stimuli of low, mid, and high spectral maxima. Aided speech-evoked auditory brainstem response was producible in all subjects. Responses evoked by stimuli with spectral maxima at dead regions had longer latencies and smaller amplitudes when compared with the control group or the responses of other stimuli. The presence of cochlear dead regions affects brainstem encoding of speech with spectral maxima perpendicular to these regions. Brainstem neuroplasticity and the extrinsic redundancy of speech can minimize the impact of dead regions in chronic hearing aid users.

Why middle-aged listeners have trouble hearing in everyday settings.

PubMed

Ruggles, Dorea; Bharadwaj, Hari; Shinn-Cunningham, Barbara G

2012-08-07

Anecdotally, middle-aged listeners report difficulty conversing in social settings, even when they have normal audiometric thresholds [1-3]. Moreover, young adult listeners with "normal" hearing vary in their ability to selectively attend to speech amid similar streams of speech. Ignoring age, these individual differences correlate with physiological differences in temporal coding precision present in the auditory brainstem, suggesting that the fidelity of encoding of suprathreshold sound helps explain individual differences [4]. Here, we revisit the conundrum of whether early aging influences an individual's ability to communicate in everyday settings. Although absolute selective attention ability is not predicted by age, reverberant energy interferes more with selective attention as age increases. Breaking the brainstem response down into components corresponding to coding of stimulus fine structure and envelope, we find that age alters which brainstem component predicts performance. Specifically, middle-aged listeners appear to rely heavily on temporal fine structure, which is more disrupted by reverberant energy than temporal envelope structure is. In contrast, the fidelity of envelope cues predicts performance in younger adults. These results hint that temporal envelope cues influence spatial hearing in reverberant settings more than is commonly appreciated and help explain why middle-aged listeners have particular difficulty communicating in daily life. Copyright © 2012 Elsevier Ltd. All rights reserved.

Gender differences in binaural speech-evoked auditory brainstem response: are they clinically significant?

PubMed

Jalaei, Bahram; Azmi, Mohd Hafiz Afifi Mohd; Zakaria, Mohd Normani

2018-05-17

Binaurally evoked auditory evoked potentials have good diagnostic values when testing subjects with central auditory deficits. The literature on speech-evoked auditory brainstem response evoked by binaural stimulation is in fact limited. Gender disparities in speech-evoked auditory brainstem response results have been consistently noted but the magnitude of gender difference has not been reported. The present study aimed to compare the magnitude of gender difference in speech-evoked auditory brainstem response results between monaural and binaural stimulations. A total of 34 healthy Asian adults aged 19-30 years participated in this comparative study. Eighteen of them were females (mean age=23.6±2.3 years) and the remaining sixteen were males (mean age=22.0±2.3 years). For each subject, speech-evoked auditory brainstem response was recorded with the synthesized syllable /da/ presented monaurally and binaurally. While latencies were not affected (p>0.05), the binaural stimulation produced statistically higher speech-evoked auditory brainstem response amplitudes than the monaural stimulation (p<0.05). As revealed by large effect sizes (d>0.80), substantive gender differences were noted in most of speech-evoked auditory brainstem response peaks for both stimulation modes. The magnitude of gender difference between the two stimulation modes revealed some distinct patterns. Based on these clinically significant results, gender-specific normative data are highly recommended when using speech-evoked auditory brainstem response for clinical and future applications. The preliminary normative data provided in the present study can serve as the reference for future studies on this test among Asian adults. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Hearing impairment in preterm very low birthweight babies detected at term by brainstem auditory evoked responses.

PubMed

Jiang, Z D; Brosi, D M; Wilkinson, A R

2001-12-01

Seventy preterm babies who were born with a birthweight <1500 g were studied with brainstem auditory evoked responses (BAER) at 37-42 wk of postconceptional age. The data were compared with those of normal term neonates to determine the prevalence of hearing impairment in preterm very low birthweight (VLBW) babies when they reached term. The BAER was recorded with click stimuli at 21 s(-1). Wave I and V latencies increased significantly (ANOVA p < 0.01 and 0.001). I-V and III-V intervals also increased significantly (p < 0.05 and 0.001). Wave V amplitude and V/I amplitude ratio did not differ significantly from those in the normal term controls. Ten of the 70 VLBW babies had a significant elevation in BAER threshold (>30 dB normal hearing level). Eleven had an increase in I-V interval (>2.5 SD above the mean in the normal controls) and one had a decrease in V/I amplitude ratio (<0.45). These results suggest that 14% (10/70) of the VLBW babies had a peripheral hearing impairment and 17% (12/70) a central impairment. Three babies had both an increase in I-V interval and an elevation in BAER threshold, suggesting that 4% (3/70) had both peripheral and central impairments. Thus, the total prevalence of hearing impairment was 27% (19/70). About one in four preterm VLBW babies has peripheral and/or central hearing impairment at term. VLBW and its associated unfavourable perinatal factors predispose the babies to hearing impairment.

Auditory Brainstem Responses in Childhood Psychosis.

ERIC Educational Resources Information Center

Gillberg, Christopher; And Others

1983-01-01

Auditory brainstem responses (ABR) were compared in 24 autistic children, seven children with other childhood psychoses, and 31 normal children. One-third of the autistic Ss showed abnormal ABR indicating brainstem dysfunction and correlating with muscular hypotonia and severe language impairment. Ss with other psychoses and normal Ss showed…

Killer whale (Orcinus orca) hearing: auditory brainstem response and behavioral audiograms.

PubMed

Szymanski, M D; Bain, D E; Kiehl, K; Pennington, S; Wong, S; Henry, K R

1999-08-01

Killer whale (Orcinus orca) audiograms were measured using behavioral responses and auditory evoked potentials (AEPs) from two trained adult females. The mean auditory brainstem response (ABR) audiogram to tones between 1 and 100 kHz was 12 dB (re 1 mu Pa) less sensitive than behavioral audiograms from the same individuals (+/- 8 dB). The ABR and behavioral audiogram curves had shapes that were generally consistent and had the best threshold agreement (5 dB) in the most sensitive range 18-42 kHz, and the least (22 dB) at higher frequencies 60-100 kHz. The most sensitive frequency in the mean Orcinus audiogram was 20 kHz (36 dB), a frequency lower than many other odontocetes, but one that matches peak spectral energy reported for wild killer whale echolocation clicks. A previously reported audiogram of a male Orcinus had greatest sensitivity in this range (15 kHz, approximately 35 dB). Both whales reliably responded to 100-kHz tones (95 dB), and one whale to a 120-kHz tone, a variation from an earlier reported high-frequency limit of 32 kHz for a male Orcinus. Despite smaller amplitude ABRs than smaller delphinids, the results demonstrated that ABR audiometry can provide a useful suprathreshold estimate of hearing range in toothed whales.

Normative behavioral thresholds for short tone-bursts.

PubMed

Beattie, R C; Rochverger, I

2001-10-01

Although tone-bursts have been commonly used in auditory brainstem response (ABR) evaluations for many years, national standards describing normal calibration values have not been established. This study was designed to gather normative threshold data to establish a physical reference for tone-burst stimuli that can be reproduced across clinics and laboratories. More specifically, we obtained norms for 3-msec tone-bursts presented at two repetition rates (9.3/sec and 39/sec), two gating functions (Trapezoid and Blackman), and four frequencies (500, 1000, 2000, and 4000 Hz). Our results are specified using three physical references: dB peak sound pressure level, dB peak-to-peak equivalent sound pressure level, and dB SPL (fast meter response, rate = 50 stimuli/sec). These data are offered for consideration when calibrating ABR equipment. The 39/sec stimulus rate yielded tone-burst thresholds that were approximately 3 dB lower than the 9.3/sec rate. The improvement in threshold with increasing stimulus rate may reflect the ability of the auditory system to integrate energy that occurs within a time interval of 200 to 500 msec (temporal integration). The Trapezoid gating function yielded thresholds that averaged 1.4 dB lower than the Blackman function. Although these differences are small and of little clinical importance, the cumulative effects of several instrument and/or procedural variables may yield clinically important differences.

Brainstem Encoding of Aided Speech in Hearing Aid Users with Cochlear Dead Region(s)

PubMed Central

Hassaan, Mohammad Ramadan; Ibraheem, Ola Abdallah; Galhom, Dalia Helal

2016-01-01

Introduction  Neural encoding of speech begins with the analysis of the signal as a whole broken down into its sinusoidal components in the cochlea, which has to be conserved up to the higher auditory centers. Some of these components target the dead regions of the cochlea causing little or no excitation. Measuring aided speech-evoked auditory brainstem response elicited by speech stimuli with different spectral maxima can give insight into the brainstem encoding of aided speech with spectral maxima at these dead regions. Objective  This research aims to study the impact of dead regions of the cochlea on speech processing at the brainstem level after a long period of hearing aid use. Methods  This study comprised 30 ears without dead regions and 46 ears with dead regions at low, mid, or high frequencies. For all ears, we measured the aided speech-evoked auditory brainstem response using speech stimuli of low, mid, and high spectral maxima. Results  Aided speech-evoked auditory brainstem response was producible in all subjects. Responses evoked by stimuli with spectral maxima at dead regions had longer latencies and smaller amplitudes when compared with the control group or the responses of other stimuli. Conclusion  The presence of cochlear dead regions affects brainstem encoding of speech with spectral maxima perpendicular to these regions. Brainstem neuroplasticity and the extrinsic redundancy of speech can minimize the impact of dead regions in chronic hearing aid users. PMID:27413404

Nociceptive Neuropeptide Increases and Periorbital Allodynia in a Model of Traumatic Brain Injury

PubMed Central

Elliott, Melanie B.; Oshinsky, Michael L.; Amenta, Peter S.; Awe, Olatilewa O.; Jallo, Jack I.

2014-01-01

Objective This study tests the hypothesis that injury to the somatosensory cortex is associated with periorbital allodynia and increases in nociceptive neuropeptides in the brainstem in a mouse model of controlled cortical impact (CCI) injury. Methods Male C57BL/6 mice received either CCI or craniotomy-only followed by weekly periorbital von Frey (mechanical) sensory testing for up to 28 days post-injury. Mice receiving an incision only and naïve mice were included as control groups. Changes in calcitonin gene-related peptide (CGRP) and substance P (SP) within the brainstem were determined using enzyme-linked immunosorbent assay and immunohistochemistry, respectively. Activation of ionized calcium-binding adaptor molecule-1–labeled macrophages/microglia and glial fibrillary acidic protein (GFAP)-positive astrocytes were evaluated using immunohistochemistry because of their potential involvement in nociceptor sensitization. Results Incision-only control mice showed no changes from baseline periorbital von Frey mechanical thresholds. CCI significantly reduced mean periorbital von Frey thresholds (periorbital allodynia) compared with baseline and craniotomy-only at each endpoint, analysis of variance P < .0001. Craniotomy significantly reduced periorbital threshold at 14 days but not 7, 21, or 28 days compared with baseline threshold, P < .01. CCI significantly increased SP immunoreactivity in the brainstem at 7 and 14 days but not 28 days compared with craniotomy-only and controls, P < .001. CGRP levels in brainstem tissues were significantly increased in CCI groups compared with controls (incision-only and naïve mice) or craniotomy-only mice at each endpoint examined, P < .0001. There was a significant correlation between CGRP and periorbital allodynia (P < .0001, r = −0.65) but not for SP (r = 0.20). CCI significantly increased the number of macrophage/microglia in the injured cortex at each endpoint up to 28 days, although cell numbers declined over weeks post-injury, P < .001. GFAP+ immunoreactivity was significantly increased at 7 but not 14 or 28 days after CCI, P < .001. Craniotomy resulted in transient periorbital allodynia accompanied by transient increases in SP, CGRP, and GFAP immunoreactivity compared with control mice. There was no increase in the number of macrophage/microglia cells compared with controls after craniotomy. Conclusion Injury to the somatosensory cortex results in persistent periorbital allodynia and increases in brainstem nociceptive neuropeptides. Findings suggest that persistent allodynia and increased neuropeptides are maintained by mechanisms other than activation of macrophage/microglia or astrocyte in the injured somatosensory cortex. PMID:22568499

Audiological findings in Noonan syndrome.

PubMed

Tokgoz-Yilmaz, Suna; Turkyilmaz, Meral Didem; Cengiz, Filiz Basak; Sjöstrand, Alev Pektas; Kose, Serdal Kenan; Tekin, Mustafa

2016-10-01

The aim of this study was to evaluate audiologic properties of patients with Noonan syndrome and compare these findings with those of unaffected peers. The study included 17 children with Noonan syndrome and 20 typically developing children without Noonan syndrome. Pure tone and speech audiometry, immitancemetric measurement, otoacoustic emissions measurement and auditory brainstem response tests were applied to all (n = 37) children. Hearing thresholds of children with Noonan syndrome were higher (poorer) than those observed unaffected peers, while the hearing sensitivity of the both groups were normal limits (p = 0.013 for right, p = 0.031 for left ear). Transient evoked otoacoustic emissions amplitudes of the children with Noonan syndrome were lower than the children without Noonan syndrome (p = 0.005 for right, p = 0.002 for left ear). Middle ear pressures and auditory brainstem response values were within normal limits and there was no difference between the two groups (p > 0.05). General benefit of the present study is to characterize the audiologic findings of children with Noonan syndrome, which is beneficial in clinics evaluating children with Noonan syndrome. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[The characteristics of auditory brainstem response in preterm very low birth weight babies].

PubMed

Wang, Xiaoya; Luo, Renzhong; Wen, Ruijin; Chen, Qian; Zhou, Jialin; Zou, Yu

2009-08-01

To discuss the characteristics of auditory brainstem response in preterm very low birth weight (VLBW) babies and to investigate the correlations between the ABR and clinical characteristics. Fifty-nine VLBW babies (118 ears) were enrolled in the study and 30 term normal babies as the control group. Tympanometry, acoustic reflex, DPOAE, ABR were obtained in all the babies. The prevalence of hearing loss in VLBW babies was higher than normal term babies and babies with perinatal complications higher than those without perinatal complications. There was no correlations between ABR threshold and gestational age, birth weight, postconceptional age, negative correlations between wave I, III and V latencies I - III, III - V and I - V intervals and postconceptional age. Wave I and V latencies, I - III and III - V intervals differed significantly between the two groups. The perinatal complications were the most important causes of the hearing loss in preterm VLBW babies than the gestational age and birth weight. There was a high prevalence of peripheral hearing loss in the preterm VLBW babies. Combining OAE and automated ABR should be applied for hearing screening. Regular follow-up was very important in all the preterm VLBW neonatal.

Brainstem auditory evoked potential wave V latency-intensity function in normal Dalmatian and Beagle puppies.

PubMed

Poncelet, L; Coppens, A; Deltenre, P

2000-01-01

This study investigated whether Dalmatian puppies with normal hearing bilaterally had the same click-evoked brainstem auditory potential characteristics as age-matched dogs of another breed. Short-latency brainstem auditory potentials evoked by condensation and rarefaction clicks were recorded in 23 1.5- to 2-month-old Dalmatian puppies with normal hearing bilaterally by a qualitative brainstem auditory evoked potential test and in 16 Beagle dogs of the same age. For each stimulus intensity, from 90 dB normal hearing level down to the wave V threshold, the sum of the potentials evoked by the 2 kinds of stimuli were added, giving an equivalent to the alternate click polarity stimulation. The slope of the L segment of the wave V latency-intensity curve was steeper in Dalmatian (-40 +/- 10 micros/dB) than in Beagles (-28 +/- 5 micros/dB, P < .001) puppies. The hearing threshold was lower in the Beagle puppies (P < .05). These results suggest that interbreed differences may exist at the level of cochlear function in this age class. The wave V latency and wave V-wave I latencies differences at high stimulus intensity were different between the groups of puppies (4.3 +/- 0.2 and 2.5 +/- 0.2 milliseconds, respectively, for Beagles; and 4.1 +/- 0.2 and 2.3 +/- 0.2 milliseconds for Dalmatians, P < .05). A different maturation speed of the neural pathways is one possible explanation of this observation.

The changing balance of brainstem–spinal cord modulation of pain processing over the first weeks of rat postnatal life

PubMed Central

Hathway, G J; Koch, S; Low, L; Fitzgerald, M

2009-01-01

Brainstem–spinal cord connections play an essential role in adult pain processing, and the modulation of spinal pain network excitability by brainstem nuclei is known to contribute to hyperalgesia and chronic pain. Less well understood is the role of descending brainstem pathways in young animals when pain networks are more excitable and exposure to injury and stress can lead to permanent modulation of pain processing. Here we show that up to postnatal day 21 (P21) in the rat, the rostroventral medulla of the brainstem (RVM) exclusively facilitates spinal pain transmission but that after this age (P28 to adult), the influence of the RVM shifts to biphasic facilitation and inhibition. Graded electrical microstimulation of the RVM at different postnatal ages revealed a robust shift in the balance of descending control of both spinal nociceptive flexion reflex EMG activity and individual dorsal horn neuron firing properties, from excitation to inhibition, beginning after P21. The shift in polarity of descending control was also observed following excitotoxic lesions of the RVM in adult and P21 rats. In adults, RVM lesions decreased behavioural mechanical sensory reflex thresholds, whereas the same lesion in P21 rats increased thresholds. These data demonstrate, for the first time, the changing postnatal influence of the RVM in spinal nociception and highlight the central role of descending brainstem control in the maturation of pain processing. PMID:19403624

Functional modeling of the human auditory brainstem response to broadband stimulationa)

PubMed Central

Verhulst, Sarah; Bharadwaj, Hari M.; Mehraei, Golbarg; Shera, Christopher A.; Shinn-Cunningham, Barbara G.

2015-01-01

Population responses such as the auditory brainstem response (ABR) are commonly used for hearing screening, but the relationship between single-unit physiology and scalp-recorded population responses are not well understood. Computational models that integrate physiologically realistic models of single-unit auditory-nerve (AN), cochlear nucleus (CN) and inferior colliculus (IC) cells with models of broadband peripheral excitation can be used to simulate ABRs and thereby link detailed knowledge of animal physiology to human applications. Existing functional ABR models fail to capture the empirically observed 1.2–2 ms ABR wave-V latency-vs-intensity decrease that is thought to arise from level-dependent changes in cochlear excitation and firing synchrony across different tonotopic sections. This paper proposes an approach where level-dependent cochlear excitation patterns, which reflect human cochlear filter tuning parameters, drive AN fibers to yield realistic level-dependent properties of the ABR wave-V. The number of free model parameters is minimal, producing a model in which various sources of hearing-impairment can easily be simulated on an individualized and frequency-dependent basis. The model fits latency-vs-intensity functions observed in human ABRs and otoacoustic emissions while maintaining rate-level and threshold characteristics of single-unit AN fibers. The simulations help to reveal which tonotopic regions dominate ABR waveform peaks at different stimulus intensities. PMID:26428802

Hearing and the round goby: Understanding the auditory system of the round goby (Neogobius melanostomus)

NASA Astrophysics Data System (ADS)

Belanger, Andrea J.; Higgs, Dennis M.

2005-04-01

The round goby (Neogobius melanostomus), is an invasive species in the Great Lakes watershed. Adult round gobies show behavioral responses to conspecific vocalizations but physiological investigations have not yet been conducted to quantify their hearing abilities. We have been examining the physiological and morphological development of the auditory system in the round goby. Various frequencies (100 Hz to 800 Hz and conspecific sounds), at various intensities (120 dB to 170 dB re 1 Pa) were presented to juveniles and adults and their auditory brain-stem responses (ABR) were recorded. Round gobies only respond physiologically to tones from 100-600 Hz, with threshold varying between 145 to 155 dB re 1 Pa. The response threshold to conspecific sounds was 140 dB re 1 Pa. There was no significant difference in auditory threshold between sizes of fish for either tones or conspecific sounds. Saccular epithelia were stained using phalloidin and there was a trend towards an increase in both hair cell number and density with an increase in fish size. These results represent a first attempt to quantify auditory abilities in this invasive species. This is an important step in understanding their reproductive physiology, which could potentially aid in their population control. [Funded by NSERC.

Tracing the neural basis of auditory entrainment.

PubMed

Lehmann, Alexandre; Arias, Diana Jimena; Schönwiesner, Marc

2016-11-19

Neurons in the auditory cortex synchronize their responses to temporal regularities in sound input. This coupling or "entrainment" is thought to facilitate beat extraction and rhythm perception in temporally structured sounds, such as music. As a consequence of such entrainment, the auditory cortex responds to an omitted (silent) sound in a regular sequence. Although previous studies suggest that the auditory brainstem frequency-following response (FFR) exhibits some of the beat-related effects found in the cortex, it is unknown whether omissions of sounds evoke a brainstem response. We simultaneously recorded cortical and brainstem responses to isochronous and irregular sequences of consonant-vowel syllable /da/ that contained sporadic omissions. The auditory cortex responded strongly to omissions, but we found no evidence of evoked responses to omitted stimuli from the auditory brainstem. However, auditory brainstem responses in the isochronous sound sequence were more consistent across trials than in the irregular sequence. These results indicate that the auditory brainstem faithfully encodes short-term acoustic properties of a stimulus and is sensitive to sequence regularity, but does not entrain to isochronous sequences sufficiently to generate overt omission responses, even for sequences that evoke such responses in the cortex. These findings add to our understanding of the processing of sound regularities, which is an important aspect of human cognitive abilities like rhythm, music and speech perception. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Neurophysiological aspects of brainstem processing of speech stimuli in audiometric-normal geriatric population.

PubMed

Ansari, M S; Rangasayee, R; Ansari, M A H

2017-03-01

Poor auditory speech perception in geriatrics is attributable to neural de-synchronisation due to structural and degenerative changes of ageing auditory pathways. The speech-evoked auditory brainstem response may be useful for detecting alterations that cause loss of speech discrimination. Therefore, this study aimed to compare the speech-evoked auditory brainstem response in adult and geriatric populations with normal hearing. The auditory brainstem responses to click sounds and to a 40 ms speech sound (the Hindi phoneme |da|) were compared in 25 young adults and 25 geriatric people with normal hearing. The latencies and amplitudes of transient peaks representing neural responses to the onset, offset and sustained portions of the speech stimulus in quiet and noisy conditions were recorded. The older group had significantly smaller amplitudes and longer latencies for the onset and offset responses to |da| in noisy conditions. Stimulus-to-response times were longer and the spectral amplitude of the sustained portion of the stimulus was reduced. The overall stimulus level caused significant shifts in latency across the entire speech-evoked auditory brainstem response in the older group. The reduction in neural speech processing in older adults suggests diminished subcortical responsiveness to acoustically dynamic spectral cues. However, further investigations are needed to encode temporal cues at the brainstem level and determine their relationship to speech perception for developing a routine tool for clinical decision-making.

Auditory brainstem activity and development evoked by apical versus basal cochlear implant electrode stimulation in children.

PubMed

Gordon, K A; Papsin, B C; Harrison, R V

2007-08-01

The role of apical versus basal cochlear implant electrode stimulation on central auditory development was examined. We hypothesized that, in children with early onset deafness, auditory development evoked by basal electrode stimulation would differ from that evoked more apically. Responses of the auditory nerve and brainstem, evoked by an apical and a basal implant electrode, were measured over the first year of cochlear implant use in 50 children with early onset severe to profound deafness who used hearing aids prior to implantation. Responses at initial stimulation were of larger amplitude and shorter latency when evoked by the apical electrode. No significant effects of residual hearing or age were found on initial response amplitudes or latencies. With implant use, responses evoked by both electrodes showed decreases in wave and interwave latencies reflecting decreased neural conduction time through the brainstem. Apical versus basal differences persisted with implant experience with one exception; eIII-eV interlatency differences decreased with implant use. Acute stimulation shows prolongation of basally versus apically evoked auditory nerve and brainstem responses in children with severe to profound deafness. Interwave latencies reflecting neural conduction along the caudal and rostral portions of the brainstem decreased over the first year of implant use. Differences in neural conduction times evoked by apical versus basal electrode stimulation persisted in the caudal but not rostral brainstem. Activity-dependent changes of the auditory brainstem occur in response to both apical and basal cochlear implant electrode stimulation.

Alteration of glycine receptor immunoreactivity in the auditory brainstem of mice following three months of exposure to radiofrequency radiation at SAR 4.0 W/kg.

PubMed

Maskey, Dhiraj; Kim, Hyung Gun; Suh, Myung-Whan; Roh, Gu Seob; Kim, Myeung Ju

2014-08-01

The increasing use of mobile communication has triggered an interest in its possible effects on the regulation of neurotransmitter signals. Due to the close proximity of mobile phones to hearing-related brain regions during usage, its use may lead to a decrease in the ability to segregate sounds, leading to serious auditory dysfunction caused by the prolonged exposure to radiofrequency (RF) radiation. The interplay among auditory processing, excitation and inhibitory molecule interactions plays a major role in auditory function. In particular, inhibitory molecules, such a glycine, are predominantly localized in the auditory brainstem. However, the effects of exposure to RF radiation on auditory function have not been reported to date. Thus, the aim of the present study was to investigate the effects of exposure to RF radiation on glycine receptor (GlyR) immunoreactivity (IR) in the auditory brainstem region at 835 MHz with a specific absorption rate of 4.0 W/kg for three months using free-floating immunohistochemistry. Compared with the sham control (SC) group, a significant loss of staining intensity of neuropils and cells in the different subdivisions of the auditory brainstem regions was observed in the mice exposed to RF radiation (E4 group). A decrease in the number of GlyR immunoreactive cells was also noted in the cochlear nuclear complex [anteroventral cochlear nucleus (AVCN), 31.09%; dorsal cochlear nucleus (DCN), 14.08%; posteroventral cochlear nucleus (PVCN), 32.79%] and the superior olivary complex (SOC) [lateral superior olivary nucleus (LSO), 36.85%; superior paraolivary nucleus (SPN), 24.33%, medial superior olivary nucleus (MSO), 23.23%; medial nucleus of the trapezoid body (MNTB), 10.15%] of the mice in the E4 group. Auditory brainstem response (ABR) analysis also revealed a significant threshold elevation of in the exposed (E4) group, which may be associated with auditory dysfunction. The present study suggests that the auditory brainstem region is susceptible to chronic exposure to RF radiation, which may affect the function of the central auditory system.

Comparison of ABR response amplitude, test time, and estimation of hearing threshold using frequency specific chirp and tone pip stimuli in newborns.

PubMed

Ferm, Inga; Lightfoot, Guy; Stevens, John

2013-06-01

To evaluate the auditory brainstem response (ABR) amplitudes evoked by tone pip and narrowband chirp (NB CE-Chirp) stimuli when testing post-screening newborns and to determine the difference in estimated hearing level correction values. Tests were performed with tone pips and NB CE-Chirps at 4 kHz or 1 kHz. The response amplitude, response quality (Fmp), and residual noise were compared for both stimuli. Thirty babies (42 ears) who passed our ABR discharge criterion at 4 kHz following referral from their newborn hearing screen. Overall, NB CE-Chirp responses were 64% larger than the tone pip responses, closer to those evoked by clicks. Fmp was significantly higher for NB CE-Chirps. It is anticipated that there could be significant reductions in test time for the same signal to noise ratio by using NB CE-Chirps when testing newborns. This effect may vary in practice and is likely to be most beneficial for babies with low amplitude ABR responses. We propose that the ABR nHL threshold to eHL correction for NB CE-Chirps should be approximately 5 dB less than the corrections for tone pips at 4 and 1 kHz.

Neural Correlates of the Binaural Masking Level Difference in Human Frequency-Following Responses.

PubMed

Clinard, Christopher G; Hodgson, Sarah L; Scherer, Mary Ellen

2017-04-01

The binaural masking level difference (BMLD) is an auditory phenomenon where binaural tone-in-noise detection is improved when the phase of either signal or noise is inverted in one of the ears (S π N o or S o N π , respectively), relative to detection when signal and noise are in identical phase at each ear (S o N o ). Processing related to BMLDs and interaural time differences has been confirmed in the auditory brainstem of non-human mammals; in the human auditory brainstem, phase-locked neural responses elicited by BMLD stimuli have not been systematically examined across signal-to-noise ratio. Behavioral and physiological testing was performed in three binaural stimulus conditions: S o N o , S π N o , and S o N π . BMLDs at 500 Hz were obtained from 14 young, normal-hearing adults (ages 21-26). Physiological BMLDs used the frequency-following response (FFR), a scalp-recorded auditory evoked potential dependent on sustained phase-locked neural activity; FFR tone-in-noise detection thresholds were used to calculate physiological BMLDs. FFR BMLDs were significantly smaller (poorer) than behavioral BMLDs, and FFR BMLDs did not reflect a physiological release from masking, on average. Raw FFR amplitude showed substantial reductions in the S π N o condition relative to S o N o and S o N π conditions, consistent with negative effects of phase summation from left and right ear FFRs. FFR amplitude differences between stimulus conditions (e.g., S o N o amplitude-S π N o amplitude) were significantly predictive of behavioral S π N o BMLDs; individuals with larger amplitude differences had larger (better) behavioral B MLDs and individuals with smaller amplitude differences had smaller (poorer) behavioral B MLDs. These data indicate a role for sustained phase-locked neural activity in BMLDs of humans and are the first to show predictive relationships between behavioral BMLDs and human brainstem responses.

Brainstem transcription of speech is disrupted in children with autism spectrum disorders

PubMed Central

Russo, Nicole; Nicol, Trent; Trommer, Barbara; Zecker, Steve; Kraus, Nina

2009-01-01

Language impairment is a hallmark of autism spectrum disorders (ASD). The origin of the deficit is poorly understood although deficiencies in auditory processing have been detected in both perception and cortical encoding of speech sounds. Little is known about the processing and transcription of speech sounds at earlier (brainstem) levels or about how background noise may impact this transcription process. Unlike cortical encoding of sounds, brainstem representation preserves stimulus features with a degree of fidelity that enables a direct link between acoustic components of the speech syllable (e.g., onsets) to specific aspects of neural encoding (e.g., waves V and A). We measured brainstem responses to the syllable /da/, in quiet and background noise, in children with and without ASD. Children with ASD exhibited deficits in both the neural synchrony (timing) and phase locking (frequency encoding) of speech sounds, despite normal click-evoked brainstem responses. They also exhibited reduced magnitude and fidelity of speech-evoked responses and inordinate degradation of responses by background noise in comparison to typically developing controls. Neural synchrony in noise was significantly related to measures of core and receptive language ability. These data support the idea that abnormalities in the brainstem processing of speech contribute to the language impairment in ASD. Because it is both passively-elicited and malleable, the speech-evoked brainstem response may serve as a clinical tool to assess auditory processing as well as the effects of auditory training in the ASD population. PMID:19635083

Early postnatal virus inoculation into the scala media achieved extensive expression of exogenous green fluorescent protein in the inner ear and preserved auditory brainstem response thresholds.

PubMed

Wang, Yunfeng; Sun, Yu; Chang, Qing; Ahmad, Shoeb; Zhou, Binfei; Kim, Yeunjung; Li, Huawei; Lin, Xi

2013-01-01

Gene transfer into the inner ear is a promising approach for treating sensorineural hearing loss. The special electrochemical environment of the scala media raises a formidable challenge for effective gene delivery at the same time as keeping normal cochlear function intact. The present study aimed to define a suitable strategy for preserving hearing after viral inoculation directly into the scala media performed at various postnatal developmental stages. We assessed transgene expression of green fluorescent protein (GFP) mediated by various types of adeno-associated virus (AAV) and lentivirus (LV) in the mouse cochlea. Auditory brainstem responses were measured 30 days after inoculation to assess effects on hearing. Patterns of GFP expression confirmed extensive exogenous gene expression in various types of cells lining the endolymphatic space. The use of different viral vectors and promoters resulted in specific cellular GFP expression patterns. AAV2/1 with cytomegalovirus promoter apparently gave the best results for GFP expression in the supporting cells. Histological examination showed normal cochlear morphology and no hair cell loss after either AAV or LV injections. We found that hearing thresholds were not significantly changed when the injections were performed in mice younger than postnatal day 5, regardless of the type of virus tested. Viral inoculation and expression in the inner ear for the restoration of hearing must not damage cochlear function. Using normal hearing mice as a model, we have achieved this necessary step, which is required for the treatment of many types of congenital deafness that require early intervention. Copyright © 2013 John Wiley & Sons, Ltd.

Auditory brainstem responses to broad-band chirps: amplitude growth functions in sedated and anaesthetised infants.

PubMed

Mühler, Roland; Rahne, Torsten; Verhey, Jesko L

2013-01-01

Recently an optimized broad-band chirp stimulus has been proposed for the objective estimation of hearing thresholds with auditory brainstem responses (ABRs). Several studies have demonstrated that this stimulus, compensating for the travelling wave delay of the frequency components of a click stimulus at the basilar membrane, evokes larger ABR amplitudes in adults. This study analyses the amplitude of chirp-evoked ABRs recorded in infants below 48 month of age under clinical conditions and compares these results with literature data. Chirp-evoked ABR recordings in 46 infants under chloral hydrate sedation or general anaesthesia were analysed retrospectively. The amplitude of the wave V was measured as a function of the stimulus intensity. To compare ABR amplitudes across infants with different hearing losses, the stimulus intensity was readjusted to the subjects' individual physiological threshold in dB SL (sensation level). Individual wave V amplitudes were plotted against stimulus intensity and individual amplitude growth functions were calculated. To investigate the maturation of chirp-evoked ABR, data from infants below and above 18 months of age were analysed separately. Chirp-evoked ABR amplitudes in both age groups were larger than the click-evoked ABR amplitudes in young infants from the literature. Amplitudes of chirp-evoked ABR in infants above 18 months of age were not substantially smaller than those reported for normal hearing adults. Amplitudes recorded in infants below 18 months were significantly smaller than those in infants above 18 months. A significant difference between chirp-evoked ABR amplitudes recorded in sedation or under general anaesthesia was not found. The higher amplitudes of ABR elicited by a broadband chirp stimulus allow for a reduction of the recording time in young infants. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Dyslexia risk gene relates to representation of sound in the auditory brainstem.

PubMed

Neef, Nicole E; Müller, Bent; Liebig, Johanna; Schaadt, Gesa; Grigutsch, Maren; Gunter, Thomas C; Wilcke, Arndt; Kirsten, Holger; Skeide, Michael A; Kraft, Indra; Kraus, Nina; Emmrich, Frank; Brauer, Jens; Boltze, Johannes; Friederici, Angela D

2017-04-01

Dyslexia is a reading disorder with strong associations with KIAA0319 and DCDC2. Both genes play a functional role in spike time precision of neurons. Strikingly, poor readers show an imprecise encoding of fast transients of speech in the auditory brainstem. Whether dyslexia risk genes are related to the quality of sound encoding in the auditory brainstem remains to be investigated. Here, we quantified the response consistency of speech-evoked brainstem responses to the acoustically presented syllable [da] in 159 genotyped, literate and preliterate children. When controlling for age, sex, familial risk and intelligence, partial correlation analyses associated a higher dyslexia risk loading with KIAA0319 with noisier responses. In contrast, a higher risk loading with DCDC2 was associated with a trend towards more stable responses. These results suggest that unstable representation of sound, and thus, reduced neural discrimination ability of stop consonants, occurred in genotypes carrying a higher amount of KIAA0319 risk alleles. Current data provide the first evidence that the dyslexia-associated gene KIAA0319 can alter brainstem responses and impair phoneme processing in the auditory brainstem. This brain-gene relationship provides insight into the complex relationships between phenotype and genotype thereby improving the understanding of the dyslexia-inherent complex multifactorial condition. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Sensory-Cognitive Interaction in the Neural Encoding of Speech in Noise: A Review

PubMed Central

Anderson, Samira; Kraus, Nina

2011-01-01

Background Speech-in-noise (SIN) perception is one of the most complex tasks faced by listeners on a daily basis. Although listening in noise presents challenges for all listeners, background noise inordinately affects speech perception in older adults and in children with learning disabilities. Hearing thresholds are an important factor in SIN perception, but they are not the only factor. For successful comprehension, the listener must perceive and attend to relevant speech features, such as the pitch, timing, and timbre of the target speaker’s voice. Here, we review recent studies linking SIN and brainstem processing of speech sounds. Purpose To review recent work that has examined the ability of the auditory brainstem response to complex sounds (cABR), which reflects the nervous system’s transcription of pitch, timing, and timbre, to be used as an objective neural index for hearing-in-noise abilities. Study Sample We examined speech-evoked brainstem responses in a variety of populations, including children who are typically developing, children with language-based learning impairment, young adults, older adults, and auditory experts (i.e., musicians). Data Collection and Analysis In a number of studies, we recorded brainstem responses in quiet and babble noise conditions to the speech syllable /da/ in all age groups, as well as in a variable condition in children in which /da/ was presented in the context of seven other speech sounds. We also measured speech-in-noise perception using the Hearing-in-Noise Test (HINT) and the Quick Speech-in-Noise Test (QuickSIN). Results Children and adults with poor SIN perception have deficits in the subcortical spectrotemporal representation of speech, including low-frequency spectral magnitudes and the timing of transient response peaks. Furthermore, auditory expertise, as engendered by musical training, provides both behavioral and neural advantages for processing speech in noise. Conclusions These results have implications for future assessment and management strategies for young and old populations whose primary complaint is difficulty hearing in background noise. The cABR provides a clinically applicable metric for objective assessment of individuals with SIN deficits, for determination of the biologic nature of disorders affecting SIN perception, for evaluation of appropriate hearing aid algorithms, and for monitoring the efficacy of auditory remediation and training. PMID:21241645

Auditory Brainstem Response Altered in Humans With Noise Exposure Despite Normal Outer Hair Cell Function

PubMed Central

Bramhall, Naomi F.; Konrad-Martin, Dawn; McMillan, Garnett P.; Griest, Susan E.

2017-01-01

Objectives Recent animal studies demonstrated that cochlear synaptopathy, a partial loss of inner hair cell-auditory nerve fiber synapses, can occur in response to noise exposure without any permanent auditory threshold shift. In animal models, this synaptopathy is associated with a reduction in the amplitude of wave I of the auditory brainstem response (ABR). The goal of this study was to determine whether higher lifetime noise exposure histories in young people with clinically normal pure-tone thresholds are associated with lower ABR wave I amplitudes. Design Twenty-nine young military Veterans and 35 non Veterans (19 to 35 years of age) with normal pure-tone thresholds were assigned to 1 of 4 groups based on their self-reported lifetime noise exposure history and Veteran status. Suprathreshold ABR measurements in response to alternating polarity tone bursts were obtained at 1, 3, 4, and 6 kHz with gold foil tiptrode electrodes placed in the ear canal. Wave I amplitude was calculated from the difference in voltage at the positive peak and the voltage at the following negative trough. Distortion product otoacoustic emission input/output functions were collected in each participant at the same four frequencies to assess outer hair cell function. Results After controlling for individual differences in sex and distortion product otoacoustic emission amplitude, the groups containing participants with higher reported histories of noise exposure had smaller ABR wave I amplitudes at suprathreshold levels across all four frequencies compared with the groups with less history of noise exposure. Conclusions Suprathreshold ABR wave I amplitudes were reduced in Veterans reporting high levels of military noise exposure and in non Veterans reporting any history of firearm use as compared with Veterans and non Veterans with lower levels of reported noise exposure history. The reduction in ABR wave I amplitude in the groups with higher levels of noise exposure cannot be accounted for by sex or variability in outer hair cell function. This change is similar to the decreased ABR wave I amplitudes observed in animal models of noise-induced cochlear synaptopathy. However, without post mortem examination of the temporal bone, no direct conclusions can be drawn concerning the presence of synaptopathy in the study groups with higher noise exposure histories. PMID:27992391

Large-scale Phenotyping of Noise-Induced Hearing Loss in 100 Strains of Mice

PubMed Central

Myint, Anthony; White, Cory H.; Ohmen, Jeffrey D.; Li, Xin; Wang, Juemei; Lavinsky, Joel; Salehi, Pezhman; Crow, Amanda L.; Ohyama, Takahiro; Friedman, Rick A.

2015-01-01

A cornerstone technique in the study of hearing is the Auditory Brainstem Response (ABR), an electrophysiologic technique that can be used as a quantitative measure of hearing function. Previous studies have published databases of baseline ABR thresholds for mouse strains, providing a valuable resource for the study of baseline hearing function and genetic mapping of hearing traits in mice. In this study, we further expand upon the existing literature by characterizing the baseline ABR characteristics of 100 inbred mouse strains, 47 of which are newly characterized for hearing function. We identify several distinct patterns of baseline hearing deficits and provide potential avenues for further investigation. Additionally, we characterize the sensitivity of the same 100 strains to noise exposure using permanent thresholds shifts, identifying several distinct patterns of noise-sensitivity. The resulting data provides a new resource for studying hearing loss and noise-sensitivity in mice. PMID:26706709

The Auditory-Brainstem Response to Continuous, Non-repetitive Speech Is Modulated by the Speech Envelope and Reflects Speech Processing

PubMed Central

Reichenbach, Chagit S.; Braiman, Chananel; Schiff, Nicholas D.; Hudspeth, A. J.; Reichenbach, Tobias

2016-01-01

The auditory-brainstem response (ABR) to short and simple acoustical signals is an important clinical tool used to diagnose the integrity of the brainstem. The ABR is also employed to investigate the auditory brainstem in a multitude of tasks related to hearing, such as processing speech or selectively focusing on one speaker in a noisy environment. Such research measures the response of the brainstem to short speech signals such as vowels or words. Because the voltage signal of the ABR has a tiny amplitude, several hundred to a thousand repetitions of the acoustic signal are needed to obtain a reliable response. The large number of repetitions poses a challenge to assessing cognitive functions due to neural adaptation. Here we show that continuous, non-repetitive speech, lasting several minutes, may be employed to measure the ABR. Because the speech is not repeated during the experiment, the precise temporal form of the ABR cannot be determined. We show, however, that important structural features of the ABR can nevertheless be inferred. In particular, the brainstem responds at the fundamental frequency of the speech signal, and this response is modulated by the envelope of the voiced parts of speech. We accordingly introduce a novel measure that assesses the ABR as modulated by the speech envelope, at the fundamental frequency of speech and at the characteristic latency of the response. This measure has a high signal-to-noise ratio and can hence be employed effectively to measure the ABR to continuous speech. We use this novel measure to show that the ABR is weaker to intelligible speech than to unintelligible, time-reversed speech. The methods presented here can be employed for further research on speech processing in the auditory brainstem and can lead to the development of future clinical diagnosis of brainstem function. PMID:27303286

Nonlinear Processing of Auditory Brainstem Response

DTIC Science & Technology

2001-10-25

Kraków, Poland Abstract: - Auditory brainstem response potentials (ABR) are signals calculated from the EEG signals registered as responses to an...acoustic activation of the auditory system. The ABR signals provide an objective, diagnostic method, widely applied in examinations of hearing organs

Effects of underwater noise on auditory sensitivity of a cyprinid fish.

PubMed

Scholik, A R; Yan, H Y

2001-02-01

The ability of a fish to interpret acoustic information in its environment is crucial for its survival. Thus, it is important to understand how underwater noise affects fish hearing. In this study, the fathead minnow (Pimephales promelas) was used to examine: (1) the immediate effects of white noise exposure (0.3-4.0 kHz, 142 dB re: 1 microPa) on auditory thresholds and (2) recovery after exposure. Audiograms were measured using the auditory brainstem response protocol and compared to baseline audiograms of fathead minnows not exposed to noise. Immediately after exposure to 24 h of white noise, five out of the eight frequencies tested showed a significantly higher threshold compared to the baseline fish. Recovery was found to depend on both duration of noise exposure and auditory frequency. These results support the hypothesis that the auditory threshold of the fathead minnow can be altered by white noise, especially in its most sensitive hearing range (0.8-2.0 kHz), and provide evidence that these effects can be long term (>14 days).

Protective Effects of α-Tocopherol on ABR Threshold Shift in Rabbits Exposed to Noise and Carbon Monoxide.

PubMed

Motallebi Kashani, Masoud; Mortazavi, Seyyed Bagher; Khavanin, Ali; Allameh, Abdolamir; Mirzaee, Ramezan; Akbari, Mehdi

2011-01-01

Noise induced hearin gloss (NIHL) is one of the most important occupational disease world wide. NIHL has been found potentiate by simultaneous carbon monoxide (CO) exposure. Free radicals have been implicated in cochlear damage resulted from the exposure to noise and due to the CO hypoxia. This study examined whether α-tocopherol administration , as a free radical scavenger, causes the attenuation of auditory brainstem response (ABR) threshold shifts resulting from noise exposure and noise plus CO exposure. Forty-two rabbits were divided in to seven groups including control, noise + saline, noise + CO + saline, noise + α-tocopherol, noise + CO + α-tocopherol , CO + α-tocopherol and α-tocopherol alone. ABR was assessed before exposure, 1 hand 14 days post exposure. The administration of 50 mg/Kg of α-tocopherol prior, following and post exposure to noise or noise plus CO recovered permanent ABR threshold shift at 1 and KHz almost to the baseline and provided significant attenuation in permanent ABR threshold shift at 4 and 8 KHz in subject swhich were exposed to noise but it did not block the potentiating of threshold elevation by CO exposure (extra threshold loss by combined exposure) at 4 and 8 KHz. α Tocopherol provides protective effect against the hearing loss resulting from noise exposure and simultaneous exposure to noise plus CO.

An animal model for the analysis of cochlear blood flow [corrected] disturbance and hearing threshold in vivo.

PubMed

Canis, Martin; Arpornchayanon, Warangkana; Messmer, Catalina; Suckfuell, Markus; Olzowy, Bernhard; Strieth, Sebastian

2010-02-01

Impairment of cochlear blood flow (CBF) is considered to be important in inner ear pathology. However, direct measurement of CBF is difficult and has not been investigated in combination with hearing function. Six guinea pigs were used to show feasibility of an animal model for the analysis of cochlear microcirculation by intravital microscopy in combination with investigation of the hearing threshold by brainstem response audiometry (ABR). By the application of sodium nitroprusside (SNP), CBF was increased over 30 min. Reproducibility of measurements was shown by retest measurements. Mean baseline velocity of CBF was 109 +/- 19 mum/s. Vessel diameters had a mean value of 9.4 +/- 2.7 mum. Mean hearing threshold was 19 +/- 6 dB. In response to SNP, CBF velocity increased significantly to 161 +/- 26 mum/s. Mean arterial pressure decreased significantly to 36 +/- 11 mmHg. After the end of the application, CBF velocity recovered to a minimum of 123 +/- 17 microm/s. Within the retest, CBF velocity significantly increased to a maximum of 160 +/- 31 microm/s. Second recovery of CBF velocity was 125 +/- 14 mum/s. Within the second retest, CBF increased significantly to 157 +/- 25 microm/s. ABR thresholds did not change significantly. The increase in blood flow velocity occurred in spite of substantial hypotension as induced by a vasodilator. This may explain the fact that ABR threshold remained unchanged reflecting a maintained blood supply in this part of the brain. This technique can be used to evaluate effects of treatments aimed at cochlear microcirculation in inner ear pathologies.

Exploring the Relationship between Physiological Measures of Cochlear and Brainstem Function

PubMed Central

Dhar, S.; Abel, R.; Hornickel, J.; Nicol, T.; Skoe, E.; Zhao, W.; Kraus, N.

2009-01-01

Objective Otoacoustic emissions and the speech-evoked auditory brainstem response are objective indices of peripheral auditory physiology and are used clinically for assessing hearing function. While each measure has been extensively explored, their interdependence and the relationships between them remain relatively unexplored. Methods Distortion product otoacoustic emissions (DPOAE) and speech-evoked auditory brainstem responses (sABR) were recorded from 28 normal-hearing adults. Through correlational analyses, DPOAE characteristics were compared to measures of sABR timing and frequency encoding. Data were organized into two DPOAE (Strength and Structure) and five brainstem (Onset, Spectrotemporal, Harmonics, Envelope Boundary, Pitch) composite measures. Results DPOAE Strength shows significant relationships with sABR Spectrotemporal and Harmonics measures. DPOAE Structure shows significant relationships with sABR Envelope Boundary. Neither DPOAE Strength nor Structure is related to sABR Pitch. Conclusions The results of the present study show that certain aspects of the speech-evoked auditory brainstem responses are related to, or covary with, cochlear function as measured by distortion product otoacoustic emissions. Significance These results form a foundation for future work in clinical populations. Analyzing cochlear and brainstem function in parallel in different clinical populations will provide a more sensitive clinical battery for identifying the locus of different disorders (e.g., language based learning impairments, hearing impairment). PMID:19346159

Auditory Brainstem Responses in Young Adults with Down Syndrome.

ERIC Educational Resources Information Center

Widen, Judith E.; And Others

1987-01-01

In a study of 15 individuals (ages 15-21) with Down Syndrome, auditory brainstem response (ABR) detection levels were elevated, response amplitude reduced, and latency-intensity functions were significantly steeper than for a matched control group. Findings were associated with an impairment in hearing sensitivity at 8000 Hz for the experimental…

Awake craniotomy for assisting placement of auditory brainstem implant in NF2 patients.

PubMed

Zhou, Qiangyi; Yang, Zhijun; Wang, Zhenmin; Wang, Bo; Wang, Xingchao; Zhao, Chi; Zhang, Shun; Wu, Tao; Li, Peng; Li, Shiwei; Zhao, Fu; Liu, Pinan

2018-06-01

Auditory brainstem implants (ABIs) may be the only opportunity for patients with NF2 to regain some sense of hearing sensation. However, only a very small number of individuals achieved open-set speech understanding and high sentence scores. Suboptimal placement of the ABI electrode array over the cochlear nucleus may be one of main factors for poor auditory performance. In the current study, we present a method of awake craniotomy to assist with ABI placement. Awake surgery and hearing test via the retrosigmoid approach were performed for vestibular schwannoma resections and auditory brainstem implantations in four patients with NF2. Auditory outcomes and complications were assessed postoperatively. Three of 4 patients who underwent awake craniotomy during ABI surgery received reproducible auditory sensations intraoperatively. Satisfactory numbers of effective electrodes, threshold levels and distinct pitches were achieved in the wake-up hearing test. In addition, relatively few electrodes produced non-auditory percepts. There was no serious complication attributable to the ABI or awake craniotomy. It is safe and well tolerated for neurofibromatosis type 2 (NF2) patients using awake craniotomy during auditory brainstem implantation. This method can potentially improve the localization accuracy of the cochlear nucleus during surgery.

Motor output evoked by subsaccadic stimulation of primate frontal eye fields.

PubMed

Corneil, Brian D; Elsley, James K; Nagy, Benjamin; Cushing, Sharon L

2010-03-30

In addition to its role in shifting the line of sight, the oculomotor system is also involved in the covert orienting of visuospatial attention. Causal evidence supporting this premotor theory of attention, or oculomotor readiness hypothesis, comes from the effect of subsaccadic threshold stimulation of the oculomotor system on behavior and neural activity in the absence of evoked saccades, which parallels the effects of covert attention. Here, by recording neck-muscle activity from monkeys and systematically titrating the level of stimulation current delivered to the frontal eye fields (FEF), we show that such subsaccadic stimulation is not divorced from immediate motor output but instead evokes neck-muscle responses at latencies that approach the minimal conduction time to the motor periphery. On average, neck-muscle thresholds were approximately 25% lower than saccade thresholds, and this difference is larger for FEF sites associated with progressively larger saccades. Importantly, we commonly observed lower neck-muscle thresholds even at sites evoking saccades

Auditory Function in Rhesus Monkeys: Effects of Aging and Caloric Restriction in the Wisconsin Monkeys Five Years Later

PubMed Central

Fowler, Cynthia G.; Chiasson, Kirstin Beach; Leslie, Tami Hanson; Thomas, Denise; Beasley, T. Mark; Kemnitz, Joseph W.; Weindruch, Richard

2010-01-01

Caloric restriction (CR) slows aging in many species and protects some animals from age-related hearing loss (ARHL), but the effect on humans is not yet known. Because rhesus monkeys are long-lived primates that are phylogenically closer to humans than other research animals are, they provide a better model for studying the effects of CR in aging and ARHL. Subjects were from the pool of 55 rhesus monkeys aged 15–28 years who had been in the Wisconsin study on CR and aging for 8–13.5 years. Distortion product otoacoustic emissions (DPOAE) with f2 frequencies from 2211–8837 Hz and auditory brainstem response (ABR) thresholds from clicks and 8, 16, and 32 kHz tone bursts were obtained. DPOAE levels declined linearly at approximately 1 dB/year, but that rate doubled for the highest frequencies in the oldest monkeys. There were no interactions for diet condition or sex. ABR thresholds to clicks and tone bursts showed increases with aging. Borderline significance was shown for diet in the thresholds at 8 kHz stimuli, with monkeys on caloric restriction having lower thresholds. Because the rhesus monkeys have a maximum longevity of 40 years, the full benefits of CR may not yet be realized. PMID:20079820

Auditory Brainstem Responses from Children Three Months to Three Years of Age: Normal Patterns of Response II.

ERIC Educational Resources Information Center

Gorga, Michael P.; And Others

1989-01-01

Auditory brainstem responses (ABR) were measured in 535 children from 3 months to 3 years of age. Results suggested that changes in wave V latency with age are due to central (neural) factors and that age-appropriate norms should be used in evaluations of ABR latencies in children. (Author/DB)

Aberrant Lateralization of Brainstem Auditory Evoked Responses by Individuals with Down Syndrome.

ERIC Educational Resources Information Center

Miezejeski, Charles M.; And Others

1994-01-01

Brainstem auditory evoked response latencies were studied in 80 males (13 with Down's syndrome). Latencies for waves P3 and P5 were shorter for Down's syndrome subjects, who also showed a different pattern of left versus right ear responses. Results suggest decreased lateralization and receptive and expressive language ability among people with…

Effects of antioxidants on auditory nerve function and survival in deafened guinea pigs.

PubMed

Maruyama, Jun; Yamagata, Takahiko; Ulfendahl, Mats; Bredberg, Göran; Altschuler, Richard A; Miller, Josef M

2007-02-01

Based on in vitro studies, it is hypothesized that neurotrophic factor deprivation following deafferentation elicits an oxidative state change in the deafferented neuron and the formation of free radicals that then signal cell death pathways. This pathway to cell death was tested in vivo by assessing the efficacy of antioxidants (AOs) to prevent degeneration of deafferented CNVIII spiral ganglion cells (SGCs) in deafened guinea pigs. Following destruction of sensory cells, guinea pigs were treated immediately with Trolox (a water soluble vitamin E analogue)+ascorbic acid (vitamin C) administered either locally, directly in the inner ear, or systemically. Electrical auditory brainstem response (EABR) thresholds were recorded to assess nerve function and showed a large increase following deafness. In treated animals EABR thresholds decreased and surviving SGCs were increased significantly compared to untreated animals. These results indicate that a change in oxidative state following deafferentation plays a role in nerve cell death and antioxidant therapy may rescue SGCs from deafferentation-induced degeneration.

Auditory Detection of the Human Brainstem Auditory Evoked Response.

ERIC Educational Resources Information Center

Kidd, Gerald, Jr.; And Others

1993-01-01

This study evaluated whether listeners can distinguish human brainstem auditory evoked responses elicited by acoustic clicks from control waveforms obtained with no acoustic stimulus when the waveforms are presented auditorily. Detection performance for stimuli presented visually was slightly, but consistently, superior to that which occurred for…

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…

Comparison between chloral hydrate and propofol-ketamine as sedation regimens for pediatric auditory brainstem response testing.

PubMed

Abulebda, Kamal; Patel, Vinit J; Ahmed, Sheikh S; Tori, Alvaro J; Lutfi, Riad; Abu-Sultaneh, Samer

2017-10-28

The use of diagnostic auditory brainstem response testing under sedation is currently the "gold standard" in infants and young children who are not developmentally capable of completing the test. The aim of the study is to compare a propofol-ketamine regimen to an oral chloral hydrate regimen for sedating children undergoing auditory brainstem response testing. Patients between 4 months and 6 years who required sedation for auditory brainstem response testing were included in this retrospective study. Drugs doses, adverse effects, sedation times, and the effectiveness of the sedative regimens were reviewed. 73 patients underwent oral chloral hydrate sedation, while 117 received propofol-ketamine sedation. 12% of the patients in the chloral hydrate group failed to achieve desired sedation level. The average procedure, recovery and total nursing times were significantly lower in the propofol-ketamine group. Propofol-ketamine group experienced higher incidence of transient hypoxemia. Both sedation regimens can be successfully used for sedating children undergoing auditory brainstem response testing. While deep sedation using propofol-ketamine regimen offers more efficiency than moderate sedation using chloral hydrate, it does carry a higher incidence of transient hypoxemia, which warrants the use of a highly skilled team trained in pediatric cardio-respiratory monitoring and airway management. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Speech-evoked Brainstem Auditory Responses and Auditory Processing Skills: A Correlation in Adults with Hearing Loss

PubMed Central

Sanguebuche, Taissane Rodrigues; Peixe, Bruna Pias; Bruno, Rúbia Soares; Biaggio, Eliara Pinto Vieira; Garcia, Michele Vargas

2018-01-01

Introduction  The auditory system consists of sensory structures and central connections. The evaluation of the auditory pathway at a central level can be performed through behavioral and electrophysiological tests, because they are complementary to each other and provide important information about comprehension. Objective  To correlate the findings of speech brainstem-evoked response audiometry with the behavioral tests Random Gap Detection Test and Masking Level Difference in adults with hearing loss. Methods  All patients were submitted to a basic audiological evaluation, to the aforementioned behavioral tests, and to an electrophysiological assessment, by means of click-evoked and speech-evoked brainstem response audiometry. Results  There were no statistically significant values among the electrophysiological test and the behavioral tests. However, there was a significant correlation between the V and A waves, as well as the D and F waves, of the speech-evoked brainstem response audiometry peaks. Such correlations are positive, indicating that the increase of a variable implies an increase in another and vice versa. Conclusion  It was possible to correlate the findings of the speech-evoked brainstem response audiometry with those of the behavioral tests Random Gap Detection and Masking Level Difference. However, there was no statistically significant correlation between them. This shows that the electrophysiological evaluation does not depend uniquely on the behavioral skills of temporal resolution and selective attention. PMID:29379574

Speech-evoked brainstem frequency-following responses during verbal transformations due to word repetition.

PubMed

Galbraith, G C; Jhaveri, S P; Kuo, J

1997-01-01

Speech-evoked brainstem frequency-following responses (FFRs) were recorded to repeated presentations of the same stimulus word. Word repetition results in illusory verbal transformations (VTs) in which word perceptions can differ markedly from the actual stimulus. Previous behavioral studies support an explanation of VTs based on changes in arousal or attention. Horizontal and vertical dipole FFRs were recorded to assess responses with putative origins in the auditory nerve and central brainstem, respectively. FFRs were recorded from 18 subjects when they correctly heard the stimulus and when they reported VTs. Although horizontal and vertical dipole FFRs showed different frequency response patterns, dipoles did not differentiate between perceptual conditions. However, when subjects were divided into low- and high-VT groups (based on percentage of VT trials), a significant Condition x Group interaction resulted. This interaction showed the largest difference in FFR amplitudes during VT trials, with the low-VT group showing increased amplitudes, and the high-VT group showing decreased amplitudes, relative to trials in which the stimulus was correctly perceived. These results demonstrate measurable subject differences in the early processing of complex signals, due to possible effects of attention on the brainstem FFR. The present research shows that the FFR is useful in understanding human language as it is coded and processed in the brainstem auditory pathway.

Brainstem response patterns in deeply-sedated critically-ill patients predict 28-day mortality.

PubMed

Rohaut, Benjamin; Porcher, Raphael; Hissem, Tarik; Heming, Nicholas; Chillet, Patrick; Djedaini, Kamel; Moneger, Guy; Kandelman, Stanislas; Allary, Jeremy; Cariou, Alain; Sonneville, Romain; Polito, Andréa; Antona, Marion; Azabou, Eric; Annane, Djillali; Siami, Shidasp; Chrétien, Fabrice; Mantz, Jean; Sharshar, Tarek

2017-01-01

Deep sedation is associated with acute brain dysfunction and increased mortality. We had previously shown that early-assessed brainstem reflexes may predict outcome in deeply sedated patients. The primary objective was to determine whether patterns of brainstem reflexes might predict mortality in deeply sedated patients. The secondary objective was to generate a score predicting mortality in these patients. Observational prospective multicenter cohort study of 148 non-brain injured deeply sedated patients, defined by a Richmond Assessment sedation Scale (RASS) <-3. Brainstem reflexes and Glasgow Coma Scale were assessed within 24 hours of sedation and categorized using latent class analysis. The Full Outline Of Unresponsiveness score (FOUR) was also assessed. Primary outcome measure was 28-day mortality. A "Brainstem Responses Assessment Sedation Score" (BRASS) was generated. Two distinct sub-phenotypes referred as homogeneous and heterogeneous brainstem reactivity were identified (accounting for respectively 54.6% and 45.4% of patients). Homogeneous brainstem reactivity was characterized by preserved reactivity to nociceptive stimuli and a partial and topographically homogenous depression of brainstem reflexes. Heterogeneous brainstem reactivity was characterized by a loss of reactivity to nociceptive stimuli associated with heterogeneous brainstem reflexes depression. Heterogeneous sub-phenotype was a predictor of increased risk of 28-day mortality after adjustment to Simplified Acute Physiology Score-II (SAPS-II) and RASS (Odds Ratio [95% confidence interval] = 6.44 [2.63-15.8]; p<0.0001) or Sequential Organ Failure Assessment (SOFA) and RASS (OR [95%CI] = 5.02 [2.01-12.5]; p = 0.0005). The BRASS (and marginally the FOUR) predicted 28-day mortality (c-index [95%CI] = 0.69 [0.54-0.84] and 0.65 [0.49-0.80] respectively). In this prospective cohort study, around half of all deeply sedated critically ill patients displayed an early particular neurological sub-phenotype predicting 28-day mortality, which may reflect a dysfunction of the brainstem.

Comparisons of auditory brainstem response and sound level tolerance in tinnitus ears and non-tinnitus ears in unilateral tinnitus patients with normal audiograms.

PubMed

Shim, Hyun Joon; An, Yong-Hwi; Kim, Dong Hyun; Yoon, Ji Eun; Yoon, Ji Hyang

2017-01-01

Recently, "hidden hearing loss" with cochlear synaptopathy has been suggested as a potential pathophysiology of tinnitus in individuals with a normal hearing threshold. Several studies have demonstrated that subjects with tinnitus and normal audiograms show significantly reduced auditory brainstem response (ABR) wave I amplitudes compared with control subjects, but normal wave V amplitudes, suggesting increased central auditory gain. We aimed to reconfirm the "hidden hearing loss" theory through a within-subject comparison of wave I and wave V amplitudes and uncomfortable loudness level (UCL), which might be decreased with increased central gain, in tinnitus ears (TEs) and non-tinnitus ears (NTEs). Human subjects included 43 unilateral tinnitus patients (19 males, 24 females) with normal and symmetric hearing thresholds and 18 control subjects with normal audiograms. The amplitudes of wave I and V from the peak to the following trough were measured twice at 90 dB nHL and we separately assessed UCLs at 500 Hz and 3000 Hz pure tones in each TE and NTE. The within-subject comparison between TEs and NTEs showed no significant differences in wave I and wave V amplitude, or wave V/I ratio in both the male and female groups. Individual data revealed increased V/I amplitude ratios > mean + 2 SD in 3 TEs, but not in any control ears. We found no significant differences in UCL at 500 Hz or 3000 Hz between the TEs and NTEs, but the UCLs of both TEs and NTEs were lower than those of the control ears. Our ABR data do not represent meaningful evidence supporting the hypothesis of cochlear synaptopathy with increased central gain in tinnitus subjects with normal audiograms. However, reduced sound level tolerance in both TEs and NTEs might reflect increased central gain consequent on hidden synaptopathy that was subsequently balanced between the ears by lateral olivocochlear efferents.

Tinnitus and Auditory Perception After a History of Noise Exposure: Relationship to Auditory Brainstem Response Measures.

PubMed

Bramhall, Naomi F; Konrad-Martin, Dawn; McMillan, Garnett P

2018-01-15

To determine whether auditory brainstem response (ABR) wave I amplitude is associated with measures of auditory perception in young people with normal distortion product otoacoustic emissions (DPOAEs) and varying levels of noise exposure history. Tinnitus, loudness tolerance, and speech perception ability were measured in 31 young military Veterans and 43 non-Veterans (19 to 35 years of age) with normal pure-tone thresholds and DPOAEs. Speech perception was evaluated in quiet using Northwestern University Auditory Test (NU-6) word lists and in background noise using the words in noise (WIN) test. Loudness discomfort levels were measured using 1-, 3-, 4-, and 6-kHz pulsed pure tones. DPOAEs and ABRs were collected in each participant to assess outer hair cell and auditory nerve function. The probability of reporting tinnitus in this sample increased by a factor of 2.0 per 0.1 µV decrease in ABR wave I amplitude (95% Bayesian confidence interval, 1.1 to 5.0) for males and by a factor of 2.2 (95% confidence interval, 1.0 to 6.4) for females after adjusting for sex and DPOAE levels. Similar results were obtained in an alternate model adjusted for pure-tone thresholds in addition to sex and DPOAE levels. No apparent relationship was found between wave I amplitude and either loudness tolerance or speech perception in quiet or noise. Reduced ABR wave I amplitude was associated with an increased risk of tinnitus, even after adjusting for DPOAEs and sex. In contrast, wave III and V amplitudes had little effect on tinnitus risk. This suggests that changes in peripheral input at the level of the inner hair cell or auditory nerve may lead to increases in central gain that give rise to the perception of tinnitus. Although the extent of synaptopathy in the study participants cannot be measured directly, these findings are consistent with the prediction that tinnitus may be a perceptual consequence of cochlear synaptopathy.

Comparisons of auditory brainstem response and sound level tolerance in tinnitus ears and non-tinnitus ears in unilateral tinnitus patients with normal audiograms

PubMed Central

An, Yong-Hwi; Kim, Dong Hyun; Yoon, Ji Eun; Yoon, Ji Hyang

2017-01-01

Objective Recently, “hidden hearing loss” with cochlear synaptopathy has been suggested as a potential pathophysiology of tinnitus in individuals with a normal hearing threshold. Several studies have demonstrated that subjects with tinnitus and normal audiograms show significantly reduced auditory brainstem response (ABR) wave I amplitudes compared with control subjects, but normal wave V amplitudes, suggesting increased central auditory gain. We aimed to reconfirm the “hidden hearing loss” theory through a within-subject comparison of wave I and wave V amplitudes and uncomfortable loudness level (UCL), which might be decreased with increased central gain, in tinnitus ears (TEs) and non-tinnitus ears (NTEs). Subjects and methods Human subjects included 43 unilateral tinnitus patients (19 males, 24 females) with normal and symmetric hearing thresholds and 18 control subjects with normal audiograms. The amplitudes of wave I and V from the peak to the following trough were measured twice at 90 dB nHL and we separately assessed UCLs at 500 Hz and 3000 Hz pure tones in each TE and NTE. Results The within-subject comparison between TEs and NTEs showed no significant differences in wave I and wave V amplitude, or wave V/I ratio in both the male and female groups. Individual data revealed increased V/I amplitude ratios > mean + 2 SD in 3 TEs, but not in any control ears. We found no significant differences in UCL at 500 Hz or 3000 Hz between the TEs and NTEs, but the UCLs of both TEs and NTEs were lower than those of the control ears. Conclusions Our ABR data do not represent meaningful evidence supporting the hypothesis of cochlear synaptopathy with increased central gain in tinnitus subjects with normal audiograms. However, reduced sound level tolerance in both TEs and NTEs might reflect increased central gain consequent on hidden synaptopathy that was subsequently balanced between the ears by lateral olivocochlear efferents. PMID:29253030

Neonatal Auditory Brainstem Responses Recorded from Four Electrode Montages.

ERIC Educational Resources Information Center

Stuart, Andrew; And Others

1996-01-01

Simultaneous auditory brainstem responses (ABRs) to click stimuli at 30 and 60 decibels were recorded from 16 full-term neonates with 4 different electrode arrays. Results indicated that ABR waveforms were morphologically similar to those recorded in adults. Waveform expression was variable with different electrode recording montages. (Author/DB)

Quantitative proteomic analysis of the brainstem following lethal sarin exposure.

PubMed

Meade, Mitchell L; Hoffmann, Andrea; Makley, Meghan K; Snider, Thomas H; Schlager, John J; Gearhart, Jeffery M

2015-06-22

The brainstem represents a major tissue area affected by sarin organophosphate poisoning due to its function in respiratory and cardiovascular control. While the acute toxic effects of sarin on brainstem-related responses are relatively unknown, other brain areas e.g., cortex or cerebellum, have been studied more extensively. The study objective was to analyze the guinea pig brainstem toxicology response following sarin (2×LD50) exposure by proteome pathway analysis to gain insight into the complex regulatory mechanisms that lead to impairment of respiratory and cardiovascular control. Guinea pig exposure to sarin resulted in the typical acute behavior/physiology outcomes with death between 15 and 25min. In addition, brain and blood acetylcholinesterase activity was significantly reduced in the presence of sarin to 95%, and 89%, respectively, of control values. Isobaric-tagged (iTRAQ) liquid chromatography tandem mass spectrometry (LC-MS/MS) identified 198 total proteins of which 23% were upregulated, and 18% were downregulated following sarin exposure. Direct gene ontology (GO) analysis revealed a sarin-specific broad-spectrum proteomic profile including glutamate-mediated excitotoxicity, calcium overload, energy depletion responses, and compensatory carbohydrate metabolism, increases in ROS defense, DNA damage and chromatin remodeling, HSP response, targeted protein degradation (ubiquitination) and cell death response. With regards to the sarin-dependent effect on respiration, our study supports the potential interference of sarin with CO2/H(+) sensitive chemoreceptor neurons of the brainstem retrotrapezoid nucleus (RTN) that send excitatory glutamergic projections to the respiratory centers. In conclusion, this study gives insight into the brainstem broad-spectrum proteome following acute sarin exposure and the gained information will assist in the development of novel countermeasures. Published by Elsevier B.V.

Acute hyperfibrinogenemia impairs cochlear blood flow and hearing function in guinea pigs in vivo.

PubMed

Ihler, Fritz; Strieth, Sebastian; Pieri, Nicos; Göhring, Peter; Canis, Martin

2012-03-01

Impairment of microcirculation is a possible cause of sudden sensorineural hearing loss (SSNHL). Fibrinogen is known as a risk factor for both microvascular dysfunction and SSNHL. Therefore, the aim of this study was to investigate the effect of elevated serum levels of fibrinogen on cochlear blood flow and hearing function in vivo. One group of guinea pigs received two consecutive injections of 100 mg fibrinogen while a control group received equimolar doses of albumin. Measurements of cochlear microcirculation by intravital microscopy and of hearing thresholds by auditory brainstem response (ABR) recordings were carried out before, after first and after second injection. Ten healthy guinea pigs were randomly assigned to a treatment group or a control group of five animals each. Serum fibrinogen levels were elevated after the first and second injections of fibrinogen compared to basal values and control group respectively. Increasing levels of fibrinogen were paralleled by decreasing cochlear blood flow as well as increasing hearing thresholds. Hearing threshold correlated negatively with cochlear blood flow. The effect of microcirculatory impairment on hearing function could be explained by a malfunction of the cochlear amplifier. Further investigation is needed to quantify cochlear potentials under elevated serum fibrinogen levels.

Deletion of SLC19A2, the high affinity thiamine transporter, causes selective inner hair cell loss and an auditory neuropathy phenotype.

PubMed

Liberman, M C; Tartaglini, E; Fleming, J C; Neufeld, E J

2006-09-01

Mutations in the gene coding for the high-affinity thiamine transporter Slc19a2 underlie the clinical syndrome known as thiamine-responsive megaloblastic anemia (TRMA) characterized by anemia, diabetes, and sensorineural hearing loss. To create a mouse model of this disease, a mutant line was created with targeted disruption of the gene. Cochlear function is normal in these mutants when maintained on a high-thiamine diet. When challenged with a low-thiamine diet, Slc19a2-null mice showed 40-60 dB threshold elevations by auditory brainstem response (ABR), but only 10-20 dB elevation by otoacoustic emission (OAE) measures. Wild-type mice retain normal hearing on either diet. Cochlear histological analysis showed a pattern uncommon for sensorineural hearing loss: selective loss of inner hair cells after 1-2 weeks on low thiamine and significantly greater inner than outer hair cell loss after longer low-thiamine challenges. Such a pattern is consistent with the observed discrepancy between ABR and OAE threshold shifts. The possible role of thiamine transport in other reported cases of selective inner hair cell loss is considered.

Inferior colliculus contributions to phase encoding of stop consonants in an animal model

PubMed Central

Warrier, Catherine M; Abrams, Daniel A; Nicol, Trent G; Kraus, Nina

2011-01-01

The human auditory brainstem is known to be exquisitely sensitive to fine-grained spectro-temporal differences between speech sound contrasts, and the ability of the brainstem to discriminate between these contrasts is important for speech perception. Recent work has described a novel method for translating brainstem timing differences in response to speech contrasts into frequency-specific phase differentials. Results from this method have shown that the human brainstem response is surprisingly sensitive to phase-differences inherent to the stimuli across a wide extent of the spectrum. Here we use an animal model of the auditory brainstem to examine whether the stimulus-specific phase signatures measured in human brainstem responses represent an epiphenomenon associated with far field (i.e., scalp-recorded) measurement of neural activity, or alternatively whether these specific activity patterns are also evident in auditory nuclei that contribute to the scalp-recorded response, thereby representing a more fundamental temporal processing phenomenon. Responses in anaesthetized guinea pigs to three minimally-contrasting consonant-vowel stimuli were collected simultaneously from the cortical surface vertex and directly from central nucleus of the inferior colliculus (ICc), measuring volume conducted neural activity and multiunit, near-field activity, respectively. Guinea pig surface responses were similar to human scalp-recorded responses to identical stimuli in gross morphology as well as phase characteristics. Moreover, surface recorded potentials shared many phase characteristics with near-field ICc activity. Response phase differences were prominent during formant transition periods, reflecting spectro-temporal differences between syllables, and showed more subtle differences during the identical steady-state periods. ICc encoded stimulus distinctions over a broader frequency range, with differences apparent in the highest frequency ranges analyzed, up to 3000 Hz. Based on the similarity of phase encoding across sites, and the consistency and sensitivity of response phase measured within ICc, results suggest that a general property of the auditory system is a high degree of sensitivity to fine-grained phase information inherent to complex acoustical stimuli. Furthermore, results suggest that temporal encoding in ICc contributes to temporal features measured in speech-evoked scalp-recorded responses. PMID:21945200

Auditory Brainstem Responses for Click and CE-chirp Stimuli in Individuals with and without Occupational Noise Exposure

PubMed Central

Pushpalatha, Zeena Venkatacheluvaiah; Konadath, Sreeraj

2016-01-01

Introduction: Encoding of CE-chirp and click stimuli in auditory system was studied using auditory brainstem responses (ABRs) among individuals with and without noise exposure. Materials and Methods: The study consisted of two groups. Group 1 (experimental group) consisted of 20 (40 ears) individuals exposed to occupational noise with hearing thresholds within 25 dB HL. They were further divided into three subgroups based on duration of noise exposure (0–5 years of exposure-T1, 5–10 years of exposure-T2, and >10 years of exposure-T3). Group 2 (control group) consisted of 20 individuals (40 ears). Absolute latency and amplitude of waves I, III, and V were compared between the two groups for both click and CE-chirp stimuli. T1, T2, and T3 groups were compared for the same parameters to see the effect of noise exposure duration on CE-chirp and click ABR. Result: In Click ABR, while both the parameters for wave III were significantly poorer for the experimental group, wave V showed a significant decline in terms of amplitude only. There was no significant difference obtained for any of the parameters for wave I. In CE-Chirp ABR, the latencies for all three waves were significantly prolonged in the experimental group. However, there was a significant decrease in terms of amplitude in only wave V for the same group. Discussion: Compared to click evoked ABR, CE-Chirp ABR was found to be more sensitive in comparison of latency parameters in individuals with occupational noise exposure. Monitoring of early pathological changes at the brainstem level can be studied effectively by using CE-Chirp stimulus in comparison to click stimulus. Conclusion: This study indicates that ABR's obtained with CE-chirp stimuli serves as an effective tool to identify the early pathological changes due to occupational noise exposure when compared to click evoked ABR. PMID:27762255

The Effect of Systemic Steroid on Hearing Preservation After Cochlear Implantation via Round Window Approach: A Guinea Pig Model.

PubMed

Chang, Mun Young; Rah, Yoon Chan; Choi, Jun Jae; Woo, Shin Wook; Hwang, Yu-Jung; Eastwood, Hayden; O'Leary, Stephen J; Lee, Jun Ho

2017-08-01

When administered perioperatively, systemic dexamethasone will reduce the hearing loss associated with cochlear implantation (CI) performed via the round window approach. The benefits of electroacoustic stimulation have led to interest in pharmacological interventions to preserve hearing after CI. Thirty guinea pigs were randomly divided into three experimental groups: a control group; a 3-day infusion group; and a 7-day infusion group. Dexamethasone was delivered via a mini-osmotic pump for either 3 or 7 days after CI via the round window. Pure tone-evoked auditory brainstem response (ABR) thresholds were monitored for a period of 12 weeks after CI. The cochleae were then collected for histology. At 4 and 12 weeks after CI, ABR threshold shifts were significantly reduced in both 7-day and 3-day infusion groups compared with the control group. Furthermore, the 7-day infusion group has significantly reduced ABR threshold shifts compared with the 3-day infusion group. The total tissue response, including fibrosis and ossification, was significantly reduced in the 7-day infusion group compared with the control group. On multiple regression the extent of fibrosis predicted hearing loss across most frequencies, while hair cell counts predicted ABR thresholds at 32 kHz. Hearing protection after systemic administration of steroids is more effective when continued for at least a week after CI. Similarly, this treatment approach was more effective in reducing the fibrosis that encapsulates the CI electrode. Reduced fibrosis seemed to be the most likely explanation for the hearing protection.

Newborn Auditory Brainstem Evoked Responses (ABRs): Longitudinal Correlates in the First Year.

ERIC Educational Resources Information Center

Murray, Ann D.

1988-01-01

Aimed to determine to what degree newborns' auditory brainstem evoked responses (ABRs) predict delayed or impaired development during the first year. When 93 infants' ABRs were evaluated at three, six, and nine months, newborn ABR was moderately sensitive for detecting hearing impairment and more sensitive than other indicators in detecting…

Evidence from Auditory Nerve and Brainstem Evoked Responses for an Organic Brain Lesion in Children with Autistic Traits

ERIC Educational Resources Information Center

Student, M.; Sohmer, H.

1978-01-01

In an attempt to resolve the question as to whether children with autistic traits have an organic nervous system lesion, auditory nerve and brainstem evoked responses were recorded in a group of 15 children (4 to 12 years old) with autistic traits. (Author)

Newborn Auditory Brainstem Evoked Responses (ABRs): Prenatal and Contemporary Correlates.

ERIC Educational Resources Information Center

Murray, Ann D.

1988-01-01

Presented are a literature review and new data on correlates of newborn auditory brainstem evoked responses (ABRs). Concludes that disorders of the central components of the ABR may be more of prenatal than of postnatal origin. The I-V interval had low but reliable correlations with four of 11 Brazelton scale variables. (RH)

Hearing Loss in Middle-Age Persons with Down Syndrome.

ERIC Educational Resources Information Center

Evenhuis, H. M.; And Others

1992-01-01

This study assessed the hearing function of 35 middle-aged adults with Down's syndrome by means of otoscopy, impedance audiometry, brainstem evoked response audiometry, and pure tone audiometry. The study found brainstem evoked response audiometry useful for routine audiological assessment, as it identified hearing losses of 20 to 90 decibels in…

Neurophysiological responses to music and vibroacoustic stimuli in Rett syndrome.

PubMed

Bergström-Isacsson, Märith; Lagerkvist, Bengt; Holck, Ulla; Gold, Christian

2014-06-01

People with Rett syndrome (RTT) have severe communicative difficulties. They have as well an immature brainstem that implies dysfunction of the autonomic nervous system. Music plays an important role in their life, is often used as a motivating tool in a variety of situations and activities, and caregivers are often clear about people with RTTs favourites. The aim of this study was to investigate physiological and emotional responses related to six different musical stimuli in people with RTT. The study included 29 participants with RTT who were referred to the Swedish Rett Center for medical brainstem assessment during the period 2006-2007. 11 children with a typical developmental pattern were used as comparison. A repeated measures design was used, and physiological data were collected from a neurophysiological brainstem assessment. The continuous dependent variables measured were Cardiac Vagal Tone (CVT), Cardiac Sensitivity to Baroreflex (CSB), Mean Arterial Blood Pressure (MAP) and the Coefficient of Variation of Mean Arterial Blood Pressure (MAP-CV). These parameters were used to categorise brainstem responses as parasympathetic (calming) response, sympathetic (activating) response, arousal (alerting) response and unclear response. The results showed that all participants responded to the musical stimuli, but not always in the expected way. It was noticeable that both people with and without RTT responded with an arousal to all musical stimuli to begin with. Even though the initial expressions sometimes changed after some time due to poor control functions of their brainstem, the present results are consistent with the possibility that the RTT participants' normal responses to music are intact. These findings may explain why music is so important for individuals with RTT throughout life. Copyright © 2014 Elsevier Ltd. All rights reserved.

Brainstem processing following unilateral and bilateral hearing-aid amplification.

PubMed

Dawes, Piers; Munro, Kevin J; Kalluri, Sridhar; Edwards, Brent

2013-04-17

Following previous research suggesting hearing-aid experience may induce functional plasticity at the peripheral level of the auditory system, click-evoked auditory brainstem response was recorded at first fitting and 12 weeks after hearing-aid use by unilateral and bilateral hearing-aid users. A control group of experienced hearing-aid users was tested over a similar time scale. No significant alterations in auditory brainstem response latency or amplitude were identified in any group. This does not support the hypothesis of plastic changes in the peripheral auditory system induced by hearing-aid use for 12 weeks.

Far-field brainstem responses evoked by vestibular and auditory stimuli exhibit increases in interpeak latency as brain temperature is decreased

NASA Technical Reports Server (NTRS)

Hoffman, L. F.; Horowitz, J. M.

1984-01-01

The effect of decreasing of brain temperature on the brainstem auditory evoked response (BAER) in rats was investigated. Voltage pulses, applied to a piezoelectric crystal attached to the skull, were used to evoke stimuli in the auditory system by means of bone-conducted vibrations. The responses were recorded at 37 C and 34 C brain temperatures. The peaks of the BAER recorded at 34 C were delayed in comparison with the peaks from the 37 C wave, and the later peaks were more delayed than the earlier peaks. These results indicate that an increase in the interpeak latency occurs as the brain temperature is decreased. Preliminary experiments, in which responses to brief angular acceleration were used to measure the brainstem vestibular evoked response (BVER), have also indicated increases in the interpeak latency in response to the lowering of brain temperature.

A comparison of the brainstem auditory evoked response in healthy ears of unilaterally deaf dogs and bilaterally hearing dogs.

PubMed

Plonek, M; Nicpoń, J; Kubiak, K; Wrzosek, M

2017-03-01

Auditory plasticity in response to unilateral deafness has been reported in various animal species. Subcortical changes occurring in unilaterally deaf young dogs using the brainstem auditory evoked response have not been evaluated yet. The aim of this study was to assess the brainstem auditory evoked response findings in dogs with unilateral hearing loss, and compare them with recordings obtained from healthy dogs. Brainstem auditory evoked responses (amplitudes and latencies of waves I, II, III, V, the V/I wave amplitude ratio, wave I-V, I-III and III-V interpeak intervals) were studied retrospectively in forty-six privately owned dogs, which were either unilaterally deaf or had bilateral hearing. The data obtained from the hearing ears in unilaterally deaf dogs were compared to values obtained from their healthy littermates. Statistically significant differences in the amplitude of wave III and the V/I wave amplitude ratio at 75 dB nHL were found between the group of unilaterally deaf puppies and the control group. The recordings of dogs with single-sided deafness were compared, and the results showed no statistically significant differences in the latencies and amplitudes of the waves between left- (AL) and right-sided (AR) deafness. The recordings of the brainstem auditory evoked response in canines with unilateral inborn deafness in this study varied compared to recordings from healthy dogs. Future studies looking into electrophysiological assessment of hearing in conjunction with imaging modalities to determine subcortical auditory plasticity and auditory lateralization in unilaterally deaf dogs are warranted.

Altered auditory function in rats exposed to hypergravic fields

NASA Technical Reports Server (NTRS)

Jones, T. A.; Hoffman, L.; Horowitz, J. M.

1982-01-01

The effect of an orthodynamic hypergravic field of 6 G on the brainstem auditory projections was studied in rats. The brain temperature and EEG activity were recorded in the rats during 6 G orthodynamic acceleration and auditory brainstem responses were used to monitor auditory function. Results show that all animals exhibited auditory brainstem responses which indicated impaired conduction and transmission of brainstem auditory signals during the exposure to the 6 G acceleration field. Significant increases in central conduction time were observed for peaks 3N, 4P, 4N, and 5P (N = negative, P = positive), while the absolute latency values for these same peaks were also significantly increased. It is concluded that these results, along with those for fields below 4 G (Jones and Horowitz, 1981), indicate that impaired function proceeds in a rostro-caudal progression as field strength is increased.

Effect of High-Pass Filtering on the Neonatal Auditory Brainstem Response to Air- and Bone-Conducted Clicks.

ERIC Educational Resources Information Center

Stuart, Andrew; Yang, Edward Y.

1994-01-01

Simultaneous 3- channel recorded auditory brainstem responses (ABR) were obtained from 20 neonates with various high-pass filter settings and low intensity levels. Results support the advocacy of less restrictive high-pass filtering for neonatal and infant ABR screening to air-conducted and bone-conducted clicks. (Author/JDD)

The Relationship between Brainstem Temporal Processing and Performance on Tests of Central Auditory Function in Children with Reading Disorders

ERIC Educational Resources Information Center

Billiet, Cassandra R.; Bellis, Teri James

2011-01-01

Purpose: Studies using speech stimuli to elicit electrophysiologic responses have found approximately 30% of children with language-based learning problems demonstrate abnormal brainstem timing. Research is needed regarding how these responses relate to performance on behavioral tests of central auditory function. The purpose of the study was to…

Auditory Brainstem Evoked Responses in Newborns with Down Syndrome

ERIC Educational Resources Information Center

Kittler, Phyllis M.; Phan, Ha T. T.; Gardner, Judith M.; Miroshnichenko, Inna; Gordon, Anne; Karmel, Bernard Z.

2009-01-01

Auditory brainstem evoked responses (ABRs) were compared in 15 newborns with Down syndrome and 15 sex-, age-, and weight-matched control newborns. Participants had normal ABRs based upon values specific to 32- to 42-weeks postconceptional age. Although Wave III and Wave V component latencies and the Wave I-III interpeak latency (IPL) were shorter…

Infant Temperament and the Brainstem Auditory Evoked Response in Later Childhood.

ERIC Educational Resources Information Center

Woodward, Sue A.; McManis, Mark H.; Kagan, Jerome; Deldin, Patricia; Snidman, Nancy; Lewis, Melissa; Kahn, Vali

2001-01-01

Evaluated brainstem auditory evoked responses (BAERs) on 10- to 12-year-olds who had been classified as high or low reactive to unfamiliar stimuli at 4 months of age. Found that children previously classified as high reactive at 4 months had larger wave V components than did low reactive children, possibly suggesting greater excitability in…

Auditory Brainstem Response to Complex Sounds Predicts Self-Reported Speech-in-Noise Performance

ERIC Educational Resources Information Center

Anderson, Samira; Parbery-Clark, Alexandra; White-Schwoch, Travis; Kraus, Nina

2013-01-01

Purpose: To compare the ability of the auditory brainstem response to complex sounds (cABR) to predict subjective ratings of speech understanding in noise on the Speech, Spatial, and Qualities of Hearing Scale (SSQ; Gatehouse & Noble, 2004) relative to the predictive ability of the Quick Speech-in-Noise test (QuickSIN; Killion, Niquette,…

Screening the High-Risk Newborn for Hearing Loss: The Crib-O-Gram v the Auditory Brainstem Response.

ERIC Educational Resources Information Center

Cox, L. Clarke

1988-01-01

Presented are a rationale for identifying hearing loss in infancy and a history of screening procedures. The Crib-O-Gram and auditory brainstem response (ABR) tests are evaluated for reliability, validity, and cost-effectiveness. The ABR is recommended, and fully automated ABR instrumentation, which lowers expenses for trained personnel and…

Plasticity of peripheral auditory frequency sensitivity in Emei music frog.

PubMed

Zhang, Dian; Cui, Jianguo; Tang, Yezhong

2012-01-01

In anurans reproductive behavior is strongly seasonal. During the spring, frogs emerge from hibernation and males vocalize for mating or advertising territories. Female frogs have the ability to evaluate the quality of the males' resources on the basis of these vocalizations. Although studies revealed that central single torus semicircularis neurons in frogs exhibit season plasticity, the plasticity of peripheral auditory sensitivity in frog is unknown. In this study the seasonally plasticity of peripheral auditory sensitivity was test in the Emei music frog Babina daunchina, by comparing thresholds and latencies of auditory brainstem responses (ABRs) evoked by tone pips and clicks in the reproductive and non-reproductive seasons. The results show that both ABR thresholds and latency differ significantly between the reproductive and non-reproductive seasons. The thresholds of tone pip evoked ABRs in the non-reproductive season increased significantly about 10 dB than those in the reproductive season for frequencies from 1 KHz to 6 KHz. ABR latencies to waveform valley values for tone pips for the same frequencies using appropriate threshold stimulus levels are longer than those in the reproductive season for frequencies from 1.5 to 6 KHz range, although from 0.2 to 1.5 KHz range it is shorter in the non-reproductive season. These results demonstrated that peripheral auditory frequency sensitivity exhibits seasonal plasticity changes which may be adaptive to seasonal reproductive behavior in frogs.

Evaluation of Treatment Thresholds for Unconjugated Hyperbilirubinemia in Preterm Infants: Effects on Serum Bilirubin and on Hearing Loss?

PubMed Central

Verkerk, Paul H.; Dijk, Peter H.; Van Straaten, Henrica L. M.

2013-01-01

Background Severe unconjugated hyperbilirubinemia may cause deafness. In the Netherlands, 25% lower total serum bilirubin (TSB) treatment thresholds were recently implemented for preterm infants. Objective To determine the rate of hearing loss in jaundiced preterms treated at high or at low TSB thresholds. Design/Methods In this retrospective study conducted at two neonatal intensive care units in the Netherlands, we included preterms (gestational age <32 weeks) treated for unconjugated hyperbilirubinemia at high or low TSB thresholds. Infants with major congenital malformations, syndromes, chromosomal abnormalities or toxoplasmosis, rubella, cytomegalovirus, herpes, syphilis, and human immunodeficiency infections were excluded. We analyzed clinical characteristics and TSB levels during the first ten postnatal days. After two failed automated Auditory Brainstem Response (ABR) tests we used the results of the diagnostic ABR examination to define normal, unilateral, and bilateral hearing loss (>35 dB). Results There were 479 patients in the high and 144 in the low threshold group. Both groups had similar gestational ages (29.5 weeks) and birth weights (1300 g). Mean and mean peak TSB levels were significantly lower after the implementation of the novel thresholds: 152±43 µmol/L and 212±52 µmol/L versus 131±37 µmol/L and 188±46 µmol/L for the high versus low thresholds, respectively (P<0.001). The incidence of hearing loss was 2.7% (13/479) in the high and 0.7% (1/144) in the low TSB threshold group (NNT = 50, 95% CI, 25–3302). Conclusions Implementation of lower treatment thresholds resulted in reduced mean and peak TSB levels. The incidence of hearing impairment in preterms with a gestational age <32 weeks treated at low TSB thresholds was substantially lower compared to preterms treated at high TSB thresholds. Further research with larger sample sizes and power is needed to determine if this effect is statistically significant. PMID:23667532

Evaluation of treatment thresholds for unconjugated hyperbilirubinemia in preterm infants: effects on serum bilirubin and on hearing loss?

PubMed

Hulzebos, Christian V; van Dommelen, Paula; Verkerk, Paul H; Dijk, Peter H; Van Straaten, Henrica L M

2013-01-01

Severe unconjugated hyperbilirubinemia may cause deafness. In the Netherlands, 25% lower total serum bilirubin (TSB) treatment thresholds were recently implemented for preterm infants. To determine the rate of hearing loss in jaundiced preterms treated at high or at low TSB thresholds. In this retrospective study conducted at two neonatal intensive care units in the Netherlands, we included preterms (gestational age <32 weeks) treated for unconjugated hyperbilirubinemia at high or low TSB thresholds. Infants with major congenital malformations, syndromes, chromosomal abnormalities or toxoplasmosis, rubella, cytomegalovirus, herpes, syphilis, and human immunodeficiency infections were excluded. We analyzed clinical characteristics and TSB levels during the first ten postnatal days. After two failed automated Auditory Brainstem Response (ABR) tests we used the results of the diagnostic ABR examination to define normal, unilateral, and bilateral hearing loss (>35 dB). There were 479 patients in the high and 144 in the low threshold group. Both groups had similar gestational ages (29.5 weeks) and birth weights (1300 g). Mean and mean peak TSB levels were significantly lower after the implementation of the novel thresholds: 152 ± 43 µmol/L and 212 ± 52 µmol/L versus 131 ± 37 µmol/L and 188 ± 46 µmol/L for the high versus low thresholds, respectively (P<0.001). The incidence of hearing loss was 2.7% (13/479) in the high and 0.7% (1/144) in the low TSB threshold group (NNT = 50, 95% CI, 25-3302). Implementation of lower treatment thresholds resulted in reduced mean and peak TSB levels. The incidence of hearing impairment in preterms with a gestational age <32 weeks treated at low TSB thresholds was substantially lower compared to preterms treated at high TSB thresholds. Further research with larger sample sizes and power is needed to determine if this effect is statistically significant.

Vestibular evoked myogenic potentials and MRI in early multiple sclerosis: Validation of the VEMP score.

PubMed

Crnošija, Luka; Krbot Skorić, Magdalena; Gabelić, Tereza; Adamec, Ivan; Habek, Mario

2017-01-15

To validate the VEMP score as a measure of brainstem dysfunction in patients with the first symptom of multiple sclerosis (MS) (clinically isolated syndrome (CIS)) and to investigate the correlation between VEMP and brainstem MRI results. 121 consecutive CIS patients were enrolled and brainstem functional system score (BSFS) was determined. Ocular VEMP (oVEMP) and cervical VEMP (cVEMP) were analyzed for latencies, conduction block and amplitude asymmetry ratio and the VEMP score was calculated. MRI was analyzed for the presence of brainstem lesions as a whole and separately for the presence of pontine, midbrain and medulla oblongata lesions. Patients with signs of brainstem involvement during the neurological examination (with BSFS ≥1) had a higher oVEMP score compared to patients with no signs of brainstem involvement. A binary logistic regression model showed that patients with brainstem lesion on the MRI are 6.780 times more likely to have BSFS ≥1 (p=0.001); and also, a higher VEMP score is associated with BSFS ≥1 (p=0.042). Furthermore, significant correlations were found between clinical brainstem involvement and brainstem and pontine MRI lesions, and prolonged latencies and/or absent VEMP responses. The VEMP score is a valuable tool in evaluation of brainstem involvement in patients with early MS. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced brainstem and cortical evoked response amplitudes: single-trial covariance analysis.

PubMed

Galbraith, G C

2001-06-01

The purpose of the present study was to develop analytic procedures that improve the definition of sensory evoked response components. Such procedures could benefit all recordings but would especially benefit difficult recordings where many trials are contaminated by muscle and movement artifacts. First, cross-correlation and latency adjustment analyses were applied to the human brainstem frequency-following response and cortical auditory evoked response recorded on the same trials. Lagged cross-correlation functions were computed, for each of 17 subjects, between single-trial data and templates consisting of the sinusoid stimulus waveform for the brainstem response and the subject's own smoothed averaged evoked response P2 component for the cortical response. Trials were considered in the analysis only if the maximum correlation-squared (r2) exceeded .5 (negatively correlated trials were thus included). Identical correlation coefficients may be based on signals with quite different amplitudes, but it is possible to assess amplitude by the nonnormalized covariance function. Next, an algorithm is applied in which each trial with negative covariance is matched to a trial with similar, but positive, covariance and these matched-trial pairs are deleted. When an evoked response signal is present in the data, the majority of trials positively correlate with the template. Thus, a residual of positively correlated trials remains after matched covariance trials are deleted. When these residual trials are averaged, the resulting brainstem and cortical responses show greatly enhanced amplitudes. This result supports the utility of this analysis technique in clarifying and assessing evoked response signals.

Specialization of the auditory processing in harbor porpoise, characterized by brain-stem potentials

NASA Astrophysics Data System (ADS)

Bibikov, Nikolay G.

2002-05-01

Brain-stem auditory evoked potentials (BAEPs) were recorded from the head surface of the three awaked harbor porpoises (Phocoena phocoena). Silver disk placed on the skin surface above the vertex bone was used as an active electrode. The experiments were performed at the Karadag biological station (the Crimea peninsula). Clicks and tone bursts were used as stimuli. The temporal and frequency selectivity of the auditory system was estimated using the methods of simultaneous and forward masking. An evident minimum of the BAEPs thresholds was observed in the range of 125-135 kHz, where the main spectral component of species-specific echolocation signal is located. In this frequency range the tonal forward masking demonstrated a strong frequency selectivity. Off-response to such tone bursts was a typical observation. An evident BAEP could be recorded up to the frequencies 190-200 kHz, however, outside the acoustical fovea the frequency selectivity was rather poor. Temporal resolution was estimated by measuring BAER recovery functions for double clicks, double tone bursts, and double noise bursts. The half-time of BAERs recovery was in the range of 0.1-0.2 ms. The data indicate that the porpoise auditory system is strongly adapted to detect ultrasonic closely spaced sounds like species-specific locating signals and echoes.

Comparison between ABR with click and narrow band chirp stimuli in children.

PubMed

Zirn, Stefan; Louza, Julia; Reiman, Viktor; Wittlinger, Natalie; Hempel, John-Martin; Schuster, Maria

2014-08-01

Click and chirp-evoked auditory brainstem responses (ABR) are applied for the estimation of hearing thresholds in children. The present study analyzes ABR thresholds across a large sample of children's ears obtained with both methods. The aim was to demonstrate the correlation between both methods using narrow band chirp and click stimuli. Click and chirp evoked ABRs were measured in 253 children aged from 0 to 18 years to determine their individual auditory threshold. The delay-compensated stimuli were narrow band CE chirps with either 2000 Hz or 4000 Hz center frequencies. Measurements were performed consecutively during natural sleep, and under sedation or general anesthesia. Threshold estimation was performed for each measurement by two experienced audiologists. Pearson-correlation analysis revealed highly significant correlations (r=0.94) between click and chirp derived thresholds for both 2 kHz and 4 kHz chirps. No considerable differences were observed either between different age ranges or gender. Comparing the thresholds estimated using ABR with click stimuli and chirp stimuli, only 0.8-2% for the 2000 Hz NB-chirp and 0.4-1.2% of the 4000 Hz NB-chirp measurements differed more than 15 dB for different degrees of hearing loss or normal hearing. The results suggest that either NB-chirp or click ABR is sufficient for threshold estimation. This holds for the chirp frequencies of 2000 Hz and 4000 Hz. The use of either click- or chirp-evoked ABR allows a reduction of recording time in young infants. Nevertheless, to cross-check the results of one of the methods, we recommend measurements with the other method as well. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Prolonged noise exposure-induced auditory threshold shifts in rats

PubMed Central

Chen, Guang-Di; Decker, Brandon; Muthaiah, Vijaya Prakash Krishnan; Sheppard, Adam; Salvi, Richard

2014-01-01

Noise-induced hearing loss (NIHL) initially increases with exposure duration, but eventually reaches an asymptotic threshold shift (ATS) once the exposure duration exceeds 18-24 h. Equations for predicting the ATS have been developed for several species, but not for rats, even though this species is extensively used in noise exposure research. To fill this void, we exposed rats to narrowband noise (NBN, 16-20 kHz) for 5 weeks starting at 80 dB SPL in the first week and then increasing the level by 6 dB per week to a final level of 104 dB SPL. Auditory brainstem responses (ABR) were recorded before, during, and following the exposure to determine the amount of hearing loss. The noise induced threshold shift to continuous long-term exposure, defined as compound threshold shift (CTS), within and above 16-20 kHz increased with noise level at the rate of 1.82 dB threshold shift per dB of noise level (NL) above a critical level (C) of 77.2 dB SPL i.e. CTS = 1.82(NL-77.2). The normalized amplitude of the largest ABR peak measured at 100 dB SPL decreased at the rate of 3.1% per dB of NL above the critical level of 76.9 dB SPL, i.e., %ABR Reduction = 3.1%(NL-76.9). ABR thresholds measured >30 days post-exposure only partially recovered resulting in a permanent threshold shift of 30-40 dB along with severe hair cell loss in the basal, high-frequency region of the cochlea. In the rat, CTS increases with noise level with a slope similar to humans and chinchillas. The critical level (C) in the rat is similar to that of humans, but higher than that of chinchillas. PMID:25219503

Repetitive Diving in Trained Rats Still Increases Fos Production in Brainstem Neurons after Bilateral Sectioning of the Anterior Ethmoidal Nerve

PubMed Central

McCulloch, Paul F.; Warren, Erik A.; DiNovo, Karyn M.

2016-01-01

This research was designed to investigate the role of the anterior ethmoidal nerve (AEN) during repetitive trained diving in rats, with specific attention to activation of afferent and efferent brainstem nuclei that are part of this reflexive response. The AEN innervates the nose and nasal passages and is thought to be an important component of the afferent limb of the diving response. Male Sprague-Dawley rats (N = 24) were trained to swim and dive through a 5 m underwater maze. Some rats (N = 12) had bilateral sectioning of the AEN, others a Sham surgery (N = 12). Twelve rats (6 AEN cut and 6 Sham) had 24 post-surgical dive trials over 2 h to activate brainstem neurons to produce Fos, a neuronal activation marker. Remaining rats were non-diving controls. Diving animals had significantly more Fos-positive neurons than non-diving animals in the caudal pressor area, ventral medullary dorsal horn, ventral paratrigeminal nucleus, nucleus tractus solitarius, rostral ventrolateral medulla, Raphe nuclei, A5, Locus Coeruleus, and Kölliker-Fuse area. There were no significant differences in brainstem Fos labeling in rats diving with and without intact AENs. Thus, the AENs are not required for initiation of the diving response. Other nerve(s) that innervate the nose and nasal passages, and/or suprabulbar activation of brainstem neurons, may be responsible for the pattern of neuronal activation observed during repetitive trained diving in rats. These results help define the central neuronal circuitry of the mammalian diving response. PMID:27148082

Time-variant fMRI activity in the brainstem and higher structures in response to acupuncture.

PubMed

Napadow, Vitaly; Dhond, Rupali; Park, Kyungmo; Kim, Jieun; Makris, Nikos; Kwong, Kenneth K; Harris, Richard E; Purdon, Patrick L; Kettner, Norman; Hui, Kathleen K S

2009-08-01

Acupuncture modulation of activity in the human brainstem is not well known. This structure is plagued by physiological artifact in neuroimaging experiments. In addition, most studies have used short (<15 min) block designs, which miss delayed responses following longer duration stimulation. We used brainstem-focused cardiac-gated fMRI and evaluated time-variant brain response to longer duration (>30 min) stimulation with verum (VA, electro-stimulation at acupoint ST-36) or sham point (SPA, non-acupoint electro-stimulation) acupuncture. Our results provide evidence that acupuncture modulates brainstem nuclei important to endogenous monoaminergic and opioidergic systems. Specifically, VA modulated activity in the substantia nigra (SN), nucleus raphe magnus, locus ceruleus, nucleus cuneiformis, and periaqueductal gray (PAG). Activation in the ventrolateral PAG was greater for VA compared to SPA. Linearly decreasing time-variant activation, suggesting classical habituation, was found in response to both VA and SPA in sensorimotor (SII, posterior insula, premotor cortex) brain regions. However, VA also produced linearly time-variant activity in limbic regions (amygdala, hippocampus, and SN), which was bimodal and not likely habituation--consisting of activation in early blocks, and deactivation by the end of the run. Thus, acupuncture induces different brain response early, compared to 20-30 min after stimulation. We attribute the fMRI differences between VA and SPA to more varied and stronger psychophysical response induced by VA. Our study demonstrates that acupuncture modulation of brainstem structures can be studied non-invasively in humans, allowing for comparison to animal studies. Our protocol also demonstrates a fMRI approach to study habituation and other time-variant phenomena over longer time durations.

Brainstem auditory evoked responses and ophthalmic findings in llamas and alpacas in eastern Canada

PubMed Central

Cullen, Cheryl L.; Lamont, Leigh A.

2006-01-01

Abstract Seventeen llamas and 23 alpacas of various coat and iris colors were evaluated for: 1) deafness by using brainstem auditory evoked response testing; and 2) for ocular abnormalities via complete ophthalmic examination. No animals were deaf. The most common ocular abnormalities noted were iris-to-iris persistent pupillary membranes and incipient cataracts. PMID:16536233

Language-experience plasticity in neural representation of changes in pitch salience

PubMed Central

Krishnan, Ananthanarayan; Gandour, Jackson T.; Suresh, Chandan H.

2016-01-01

Neural representation of pitch-relevant information at the brainstem and cortical levels of processing is influenced by language experience. A well-known attribute of pitch is its salience. Brainstem frequency following responses and cortical pitch specific responses, recorded concurrently, were elicited by a pitch salience continuum spanning weak to strong pitch of a dynamic, iterated rippled noise pitch contour—homolog of a Mandarin tone. Our aims were to assess how language experience (Chinese, English) affects i) enhancement of neural activity associated with pitch salience at brainstem and cortical levels, ii) the presence of asymmetry in cortical pitch representation, and iii) patterns of relative changes in magnitude along the pitch salience continuum. Peak latency (Fz: Na, Pb, Nb) was shorter in the Chinese than the English group across the continuum. Peak-to-peak amplitude (Fz: Na-Pb, Pb-Nb) of the Chinese group grew larger with increasing pitch salience, but an experience-dependent advantage was limited to the Na-Pb component. At temporal sites (T7/T8), the larger amplitude of the Chinese group across the continuum was both limited to the Na-Pb component and the right temporal site. At the brainstem level, F0 magnitude gets larger as you increase pitch salience, and it too reveals Chinese superiority. A direct comparison of cortical and brainstem responses for the Chinese group reveals different patterns of relative changes in magnitude along the pitch salience continuum. Such differences may point to a transformation in pitch processing at the cortical level presumably mediated by local sensory and/or extrasensory influence overlaid on the brainstem output. PMID:26903418

Learning Disability Assessed through Audiologic and Physiologic Measures: A Case Study.

ERIC Educational Resources Information Center

Greenblatt, Edward R.; And Others

1983-01-01

The report describes a child with central auditory dysfunction, the first reported case where brain-stem dysfunction on audiologic tests were associated with specific electrophysiologic changes in the brain-stem auditory-evoked responses. (Author/CL)

The auditory brain-stem response to complex sounds: a potential biomarker for guiding treatment of psychosis.

PubMed

Tarasenko, Melissa A; Swerdlow, Neal R; Makeig, Scott; Braff, David L; Light, Gregory A

2014-01-01

Cognitive deficits limit psychosocial functioning in schizophrenia. For many patients, cognitive remediation approaches have yielded encouraging results. Nevertheless, therapeutic response is variable, and outcome studies consistently identify individuals who respond minimally to these interventions. Biomarkers that can assist in identifying patients likely to benefit from particular forms of cognitive remediation are needed. Here, we describe an event-related potential (ERP) biomarker - the auditory brain-stem response (ABR) to complex sounds (cABR) - that appears to be particularly well-suited for predicting response to at least one form of cognitive remediation that targets auditory information processing. Uniquely, the cABR quantifies the fidelity of sound encoded at the level of the brainstem and midbrain. This ERP biomarker has revealed auditory processing abnormalities in various neurodevelopmental disorders, correlates with functioning across several cognitive domains, and appears to be responsive to targeted auditory training. We present preliminary cABR data from 18 schizophrenia patients and propose further investigation of this biomarker for predicting and tracking response to cognitive interventions.

Audiological and electrophysiological evaluation of children with acquired immunodeficiency syndrome (AIDS).

PubMed

Matas, Carla Gentile; Leite, Renata Aparecida; Magliaro, Fernanda Cristina Leite; Gonçalves, Isabela Crivellaro

2006-08-01

We examined the peripheral auditory system and the auditory brainstem pathway of children with Acquired Immunodeficiency Syndrome (AIDS). One hundred and one children, 51 with AIDS diagnosis and 50 normal children were evaluated. Audiological assessment included immittance measures, pure tone and speech audiometry and auditory brainstem response (ABR). The children with AIDS more frequently had abnormal results than did their matched controls, presenting either peripheral or auditory brainstem impairment. We suggest that AIDS be considered a risk factor for peripheral and/or auditory brainstem disorders. Further research should be carried out to investigate the auditory effects of HIV infection along the auditory pathway.

Auditory cortical responses in patients with cochlear implants

PubMed Central

Burdo, S; Razza, S; Di Berardino, F; Tognola, G

2006-01-01

Summary Currently, the most commonly used electrophysiological tests for cochlear implant evaluation are Averaged Electrical Voltages (AEV), Electrical Advisory Brainstem Responses (EABR) and Neural Response Telemetry (NRT). The present paper focuses on the study of acoustic auditory cortical responses, or slow vertex responses, which are not widely used due to the difficulty in recording, especially in young children. Aims of this study were validation of slow vertex responses and their possible applications in monitoring postimplant results, particularly restoration of hearing and auditory maturation. In practice, the use of tone-bursts, also through hearing aids or cochlear implants, as in slow vertex responses, allows many more frequencies to be investigated and louder intensities to be reached than with other tests based on a click as stimulus. Study design focused on latencies of N1 and P2 slow vertex response peaks in cochlear implants. The study population comprised 45 implant recipients (aged 2 to 70 years), divided into 5 different homogeneous groups according to chronological age, age at onset of deafness, and age at implantation. For each subject, slow vertex responses and free-field auditory responses (PTAS) were recorded for tone-bursts at 500 and 2000 Hz before cochlear implant surgery (using hearing aid amplification) and during scheduled sessions at 3rd and 12th month after implant activation. Results showed that N1 and P2 latencies decreased in all groups starting from 3rd through 12th month after activation. Subjects implanted before school age or at least before age 8 yrs showed the widest latency changes. All subjects showed a reduction in the gap between subjective thresholds (obtained with free field auditory responses) and objective thresholds (obtained with slow vertex responses), obtained in presurgery stage and after cochlear implant. In conclusion, a natural evolution of neurophysiological cortical activities of the auditory pathway, over time, was found especially in young children with prelingual deafness and implanted in preschool age. Cochlear implantation appears to provide hearing restoration, demonstrated by the sharp reduction of the gap between subjective free field auditory responses and slow vertex responses threshold obtained with hearing aids vs. cochlear implant. PMID:16886849

The role of RIP3 mediated necroptosis in ouabain-induced spiral ganglion neurons injuries.

PubMed

Wang, Xi; Wang, Ye; Ding, Zhong-jia; Yue, Bo; Zhang, Peng-zhi; Chen, Xiao-dong; Chen, Xin; Chen, Jun; Chen, Fu-quan; Chen, Yang; Wang, Ren-feng; Mi, Wen-juan; Lin, Ying; Wang, Jie; Qiu, Jian-hua

2014-08-22

Spiral ganglion neuron (SGN) injury is a generally accepted precursor of auditory neuropathy. Receptor-interacting protein 3 (RIP3) has been reported as an important necroptosis pathway mediator that can be blocked by necrostatin-1 (Nec-1). In our study, we sought to identify whether necroptosis participated in SGN injury. Ouabain was applied to establish an SGN injury model. We measured the auditory brain-stem response (ABR) threshold shift as an indicator of the auditory conditions. Positive β3-tubulin immunofluorescence staining indicated the surviving SGNs. RIP3 expression was evaluated using immunofluorescence, quantitative real-time polymerase chain reaction and western blot. SGN injury promoted an increase in RIP3 expression that could be suppressed by application of the necroptosis inhibitor Nec-1. A decreased ABR threshold shift and increased SGN density were observed when Nec-1 was administered with apoptosis inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD). These results demonstrated that necroptosis is an indispensable pathway separately from apoptosis leading to SGN death pathway, in which RIP3 plays an important role. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Leupeptin reduces impulse noise induced hearing loss

PubMed Central

2011-01-01

Background Exposure to continuous and impulse noise can induce a hearing loss. Leupeptin is an inhibitor of the calpains, a family of calcium-activated proteases which promote cell death. The objective of this study is to assess whether Leupeptin could reduce the hearing loss resulting from rifle impulse noise. Methods A polyethelene tube was implanted into middle ear cavities of eight fat sand rats (16 ears). Following determination of auditory nerve brainstem evoked response (ABR) threshold in each ear, the animals were exposed to the noise of 10 M16 rifle shots. Immediately after the exposure, saline was then applied to one (control) ear and non-toxic concentrations of leupeptin determined in the first phase of the study were applied to the other ear, for four consecutive days. Results Eight days after the exposure, the threshold shift (ABR) in the control ears was significantly greater (44 dB) than in the leupeptin ears (27 dB). Conclusion Leupeptin applied to the middle ear cavity can reduce the hearing loss resulting from exposure to impulse noise. PMID:22206578

Hearing assessment during deep brain stimulation of the central nucleus of the inferior colliculus and dentate cerebellar nucleus in rat.

PubMed

Smit, Jasper V; Jahanshahi, Ali; Janssen, Marcus L F; Stokroos, Robert J; Temel, Yasin

2017-01-01

Recently it has been shown in animal studies that deep brain stimulation (DBS) of auditory structures was able to reduce tinnitus-like behavior. However, the question arises whether hearing might be impaired when interfering in auditory-related network loops with DBS. The auditory brainstem response (ABR) was measured in rats during high frequency stimulation (HFS) and low frequency stimulation (LFS) in the central nucleus of the inferior colliculus (CIC, n  = 5) or dentate cerebellar nucleus (DCBN, n  = 5). Besides hearing thresholds using ABR, relative measures of latency and amplitude can be extracted from the ABR. In this study ABR thresholds, interpeak latencies (I-III, III-V, I-V) and V/I amplitude ratio were measured during off-stimulation state and during LFS and HFS. In both the CIC and the CNBN groups, no significant differences were observed for all outcome measures. DBS in both the CIC and the CNBN did not have adverse effects on hearing measurements. These findings suggest that DBS does not hamper physiological processing in the auditory circuitry.

Evidence of "hidden hearing loss" following noise exposures that produce robust TTS and ABR wave-I amplitude reductions.

PubMed

Lobarinas, Edward; Spankovich, Christopher; Le Prell, Colleen G

2017-06-01

In animals, noise exposures that produce robust temporary threshold shifts (TTS) can produce immediate damage to afferent synapses and long-term degeneration of low spontaneous rate auditory nerve fibers. This synaptopathic damage has been shown to correlate with reduced auditory brainstem response (ABR) wave-I amplitudes at suprathreshold levels. The perceptual consequences of this "synaptopathy" remain unknown but have been suggested to include compromised hearing performance in competing background noise. Here, we used a modified startle inhibition paradigm to evaluate whether noise exposures that produce robust TTS and ABR wave-I reduction but not permanent threshold shift (PTS) reduced hearing-in-noise performance. Animals exposed to 109 dB SPL octave band noise showed TTS >30 dB 24-h post noise and modest but persistent ABR wave-I reduction 2 weeks post noise despite full recovery of ABR thresholds. Hearing-in-noise performance was negatively affected by the noise exposure. However, the effect was observed only at the poorest signal to noise ratio and was frequency specific. Although TTS >30 dB 24-h post noise was a predictor of functional deficits, there was no relationship between the degree of ABR wave-I reduction and degree of functional impairment. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of erythropoietin on acoustically traumatized rat cochlea: an immunohistochemical study.

PubMed

Gürgen, Oğuzhan; Gürgen, Seren Gülşen; Kirkim, Günay; Kolatan, Efsun; Gürkan, Selhan; Güvenç, Yeşim; Eskiizmir, Görkem

2014-08-01

To investigate the audiological and histopathological effects of erythropoietin on acoustic overstimulation in rats. Twenty-two male Wistar albino rats were divided into 3 groups: sham group (n = 7), erythropoietin injection group (n = 8), and saline injection group (n = 7). Both erythropoietin and saline injection groups were exposed to white noise (100 decibel [dB] sound pressure level [SPL]) for 3 hours. Auditory brainstem responses were measured before, immediately after, and on the 7th day of noise exposure. All animals were sacrificed on the 7th day and temporal bones were collected. The serial sections of the cochleae were stained by caspase-3 and caspase-9 immunostaining and by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method in order to detect apoptotic cells. In the saline group statistically significant differences were detected between the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli. However, when the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli were compared in the erythropoietin injection group, no statistically significant difference was determined. Histopathologic evaluations demonstrated that erythropoietin decreased the amount of apoptotic cells in the cochlea. Erythropoietin is likely to prevent the acute threshold changes and decrease the amount of apoptosis in cochlea after acoustic overstimulation in rats.

Effects of carbogen on cochlear blood flow and hearing function following acute acoustic trauma in guinea pigs.

PubMed

Zhao, Jing; Sun, Jianjun; Liu, Yang

2012-10-01

Disturbances of microcirculation and hemorheological changes in the inner ear are the results of noise-induced hearing loss (NIHL). Both the disturbances of microcirculation and hemorheological changes are the etiologies of NIHL development, but they are also the results. Although previous reports that inhalation of high concentration of CO(2) may increase cochlear blood flow (CoBF), the effects of carbogen on the cochlear microcirculation and NIHL remain unclear. Changes induced by noise, carbogen and pure oxygen within the cochlear lateral wall microvasculature and in hearing thresholds were observed in guinea pigs using intravital microscopy and the auditory brainstem response. At the same time, arterial oxygen saturation and morphologic changes of cochlear hair cells were observed. Carbogen inhalation increased vessel diameters and blood flow velocities. Hearing thresholds elevation in the carbogen group was smaller than those in the control and oxygen group (p <0.05). Carbogen inhalation produced a trend toward less threshold shift after noise exposure, which reached statistical significance after day 3 (p <0.01). Respiratory acidosis was not found in our study. The segmented basal membranes of Corti in three groups indicated that no losses or discorders of hair cells were found. Carbogen inhalation can preserve hearing in animal models after acute acoustic trauma. Copyright © 2012 IMSS. All rights reserved.

Functional impairment of the auditory pathway after perinatal asphyxia and the short-term effect of perinatal propofol anesthesia in lambs.

PubMed

Smit, Adriana L; Seehase, Matthias; Stokroos, Robert J; Jellema, Reint K; Felipe, Lilian; Chenault, Michelene N; Anteunis, Lucien J C; Kremer, Bernd; Kramer, Boris W

2013-07-01

Sensorineural hearing loss (SNHL) is a common feature in the postasphyxial syndrome in newborns. Several anesthetic drugs have been proposed to attenuate secondary neuronal injury elicited by hypoxia-ischemia. We hypothesized that propofol anesthesia reduces auditory impairment after perinatal asphyxia in comparison with isoflurane. Twenty-three pregnant ewes were randomized to propofol or isoflurane anesthesia and sedation. The lambs underwent in utero umbilical cord occlusion (isoflurane n = 5; propofol n = 7) and were compared with sham-treated animals (isoflurane n = 5; propofol n = 6) at a gestational age of 133 d. For 8 h after delivery by cesarean section, repeated auditory brainstem responses (ABRs) were recorded to obtain hearing thresholds, peak amplitudes, latencies, and interpeak latencies. Significantly elevated mean thresholds, diminished amplitudes, and elevated latencies were observed in the asphyxia group relative to the control group through the observation period. Comparison of anesthetic treatment in the asphyxia group revealed a significantly lower elevation in threshold and less impairment in the ABR amplitudes and latencies during propofol anesthesia as compared with isoflurane anesthesia. Our results support the hypothesis that anesthesia with propofol has a preventive effect on the functional changes to the auditory pathway in the event of perinatal asphyxia.

Clinical applications of the human brainstem responses to auditory stimuli

NASA Technical Reports Server (NTRS)

Galambos, R.; Hecox, K.

1975-01-01

A technique utilizing the frequency following response (FFR) (obtained by auditory stimulation, whereby the stimulus frequency and duration are mirror-imaged in the resulting brainwaves) as a clinical tool for hearing disorders in humans of all ages is presented. Various medical studies are discussed to support the clinical value of the technique. The discovery and origin of the FFR and another significant brainstem auditory response involved in studying the eighth nerve is also discussed.

Evidence for Atypical Auditory Brainstem Responses in Young Children with Suspected Autism Spectrum Disorders

ERIC Educational Resources Information Center

Roth, Daphne Ari-Even; Muchnik, Chava; Shabtai, Esther; Hildesheimer, Minka; Henkin, Yael

2012-01-01

Aim: The aim of this study was to characterize the auditory brainstem responses (ABRs) of young children with suspected autism spectrum disorders (ASDs) and compare them with the ABRs of children with language delay and with clinical norms. Method: The ABRs of 26 children with suspected ASDs (21 males, five females; mean age 32.5 mo) and an age-…

Sensory Processing of Backward-Masking Signals in Children with Language-Learning Impairment as Assessed with the Auditory Brainstem Response.

ERIC Educational Resources Information Center

Marler, Jeffrey A.; Champlin, Craig A.

2005-01-01

The purpose of this study was to examine the possible contribution of sensory mechanisms to an auditory processing deficit shown by some children with language-learning impairment (LLI). Auditory brainstem responses (ABRs) were measured from 2 groups of school-aged (8-10 years) children. One group consisted of 10 children with LLI, and the other…

Mechanisms of spectral and temporal integration in the mustached bat inferior colliculus

PubMed Central

Wenstrup, Jeffrey James; Nataraj, Kiran; Sanchez, Jason Tait

2012-01-01

This review describes mechanisms and circuitry underlying combination-sensitive response properties in the auditory brainstem and midbrain. Combination-sensitive neurons, performing a type of auditory spectro-temporal integration, respond to specific, properly timed combinations of spectral elements in vocal signals and other acoustic stimuli. While these neurons are known to occur in the auditory forebrain of many vertebrate species, the work described here establishes their origin in the auditory brainstem and midbrain. Focusing on the mustached bat, we review several major findings: (1) Combination-sensitive responses involve facilitatory interactions, inhibitory interactions, or both when activated by distinct spectral elements in complex sounds. (2) Combination-sensitive responses are created in distinct stages: inhibition arises mainly in lateral lemniscal nuclei of the auditory brainstem, while facilitation arises in the inferior colliculus (IC) of the midbrain. (3) Spectral integration underlying combination-sensitive responses requires a low-frequency input tuned well below a neuron's characteristic frequency (ChF). Low-ChF neurons in the auditory brainstem project to high-ChF regions in brainstem or IC to create combination sensitivity. (4) At their sites of origin, both facilitatory and inhibitory combination-sensitive interactions depend on glycinergic inputs and are eliminated by glycine receptor blockade. Surprisingly, facilitatory interactions in IC depend almost exclusively on glycinergic inputs and are largely independent of glutamatergic and GABAergic inputs. (5) The medial nucleus of the trapezoid body (MNTB), the lateral lemniscal nuclei, and the IC play critical roles in creating combination-sensitive responses. We propose that these mechanisms, based on work in the mustached bat, apply to a broad range of mammals and other vertebrates that depend on temporally sensitive integration of information across the audible spectrum. PMID:23109917

Reticular formation responses to magnetic brain stimulation of primary motor cortex

PubMed Central

Fisher, Karen M; Zaaimi, Boubker; Baker, Stuart N

2012-01-01

Transcranial magnetic stimulation (TMS) of cerebral cortex is a popular technique for the non-invasive investigation of motor function. TMS is often assumed to influence spinal circuits solely via the corticospinal tract. We were interested in possible trans-synaptic effects of cortical TMS on the ponto-medullary reticular formation in the brainstem, which is the source of the reticulospinal tract and could also generate spinal motor output. We recorded from 210 single units in the reticular formation of three anaesthetized macaque monkeys whilst TMS was performed over primary motor cortex. Short latency responses were observed consistent with activation of a cortico-reticular pathway. However, we also demonstrated surprisingly powerful responses at longer latency, which often appeared at lower threshold than the earlier effects. These late responses seemed to be generated partly as a consequence of the sound click made by coil discharge, and changed little with coil location. This novel finding has implications for the design of future studies using TMS, as well as suggesting a means of non-invasively probing an otherwise inaccessible important motor centre. PMID:22674723

Reticular formation responses to magnetic brain stimulation of primary motor cortex.

PubMed

Fisher, Karen M; Zaaimi, Boubker; Baker, Stuart N

2012-08-15

Transcranial magnetic stimulation (TMS) of cerebral cortex is a popular technique for the non-invasive investigation of motor function. TMS is often assumed to influence spinal circuits solely via the corticospinal tract. We were interested in possible trans-synaptic effects of cortical TMS on the ponto-medullary reticular formation in the brainstem, which is the source of the reticulospinal tract and could also generate spinal motor output. We recorded from 210 single units in the reticular formation of three anaesthetized macaque monkeys whilst TMS was performed over primary motor cortex. Short latency responses were observed consistent with activation of a cortico-reticular pathway. However, we also demonstrated surprisingly powerful responses at longer latency, which often appeared at lower threshold than the earlier effects. These late responses seemed to be generated partly as a consequence of the sound click made by coil discharge, and changed little with coil location. This novel finding has implications for the design of future studies using TMS, as well as suggesting a means of non-invasively probing an otherwise inaccessible important motor centre.

Auditory responses to electric and infrared neural stimulation of the rat cochlear nucleus.

PubMed

Verma, Rohit U; Guex, Amélie A; Hancock, Kenneth E; Durakovic, Nedim; McKay, Colette M; Slama, Michaël C C; Brown, M Christian; Lee, Daniel J

2014-04-01

In an effort to improve the auditory brainstem implant, a prosthesis in which user outcomes are modest, we applied electric and infrared neural stimulation (INS) to the cochlear nucleus in a rat animal model. Electric stimulation evoked regions of neural activation in the inferior colliculus and short-latency, multipeaked auditory brainstem responses (ABRs). Pulsed INS, delivered to the surface of the cochlear nucleus via an optical fiber, evoked broad neural activation in the inferior colliculus. Strongest responses were recorded when the fiber was placed at lateral positions on the cochlear nucleus, close to the temporal bone. INS-evoked ABRs were multipeaked but longer in latency than those for electric stimulation; they resembled the responses to acoustic stimulation. After deafening, responses to electric stimulation persisted, whereas those to INS disappeared, consistent with a reported "optophonic" effect, a laser-induced acoustic artifact. Thus, for deaf individuals who use the auditory brainstem implant, INS alone did not appear promising as a new approach. Copyright © 2014 Elsevier B.V. All rights reserved.

Auditory Responses to Electric and Infrared Neural Stimulation of the Rat Cochlear Nucleus

PubMed Central

Verma, Rohit; Guex, Amelie A.; Hancock, Kenneth E.; Durakovic, Nedim; McKay, Colette M.; Slama, Michaël C. C.; Brown, M. Christian; Lee, Daniel J.

2014-01-01

In an effort to improve the auditory brainstem implant, a prosthesis in which user outcomes are modest, we applied electric and infrared neural stimulation (INS) to the cochlear nucleus in a rat animal model. Electric stimulation evoked regions of neural activation in the inferior colliculus and short-latency, multipeaked auditory brainstem responses (ABRs). Pulsed INS, delivered to the surface of the cochlear nucleus via an optical fiber, evoked broad neural activation in the inferior colliculus. Strongest responses were recorded when the fiber was placed at lateral positions on the cochlear nucleus, close to the temporal bone. INS-evoked ABRs were multipeaked but longer in latency than those for electric stimulation; they resembled the responses to acoustic stimulation. After deafening, responses to electric stimulation persisted, whereas those to INS disappeared, consistent with a reported “optophonic” effect, a laser-induced acoustic artifact. Thus, for deaf individuals who use the auditory brainstem implant, INS alone did not appear promising as a new approach. PMID:24508368

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.

[Effects of sildenafil citrate on mice hearing].

PubMed

Luo, Xiaoqin; Guo, Xuyao; Chen, Lin; Chen, Xiaohong; Zhang, Xueyuan; Yuan, Wei

2014-06-01

The purpose of this investigation was to study the effects of the Sildenafil citrate on mice hearing. Seven-week-old adult male Kunming mice were used. The mice were randomly divided into four groups with 10 mice in each group.Sildenafil groups were orally administered daily with sildenafil [0.1 mg/(kg·d), 1 mg/(kg·d), 10 mg/(kg·d)] and control group was orally administered with normal saline. Then mice were tested for auditory brainstem response (ABR) to observe the changes of ABR's thresholds at before administration and 1, 5, 10, 15, 20 day afterwards. The mice basilar membrane samples were studied by immunofluorescent labeling.High performance liquid chromatography was used for determination the concentration of sildenafil in endolymph of mice cochlea. Statistical analysis was performed using SPSS 13.0. After 30 min following administration, the Sildenafil in endolymph of mice cochlear could be assayed by high performance liquid chromatography, and it was dose-related.Sildenafil increased the hearing thresholds with the time of administration. Hearing thresholds increased significantly in the sildenafil group at 20 d compared to the control group (P < 0.05). After administered high dose of Sildenafil, on the 20th day, the ABR thresholds average threshold was (60.0 ± 10.0) dBnHL, and the control group was (14.5 ± 6.0) dBnHL.Hair cells damages in the base ring of cochlea could be observed in experimental group in a concentration-dependent manner. Sildenafil can pass through blood-labyrinth barrier to the inner ear, and doses of sildenafil administration can induce hearing impairment in mice.

Monitoring the Hearing Handicap and the Recognition Threshold of Sentences of a Patient with Unilateral Auditory Neuropathy Spectrum Disorder with Use of a Hearing Aid.

PubMed

Lima, Aline Patrícia; Mantello, Erika Barioni; Anastasio, Adriana Ribeiro Tavares

2016-04-01

Introduction Treatment for auditory neuropathy spectrum disorder (ANSD) is not yet well established, including the use of hearing aids (HAs). Not all patients diagnosed with ASND have access to HAs, and in some cases HAs are even contraindicated. Objective To monitor the hearing handicap and the recognition threshold of sentences in silence and in noise in a patient with ASND using an HA. Resumed Report A 47-year-old woman reported moderate sensorineural hearing loss in the right ear and high-frequency loss of 4 kHz in the left ear, with bilateral otoacoustic emissions. Auditory brainstem response suggested changes in the functioning of the auditory pathway (up to the inferior colliculus) on the right. An HA was indicated on the right. The patient was tested within a 3-month period before the HA fitting with respect to recognition threshold of sentences in quiet and in noise and for handicap determination. After HA use, she showed a 2.1-dB improvement in the recognition threshold of sentences in silence, a 6.0-dB improvement for recognition threshold of sentences in noise, and a rapid improvement of the signal-to-noise ratio from +3.66 to -2.4 dB when compared with the same tests before the fitting of the HA. Conclusion There was a reduction of the auditory handicap, although speech perception continued to be severely limited. There was a significant improvement of the recognition threshold of sentences in silence and in noise and of the signal-to-noise ratio after 3 months of HA use.

The effect of systemic lipoic acid on hearing preservation after cochlear implantation via the round window approach: A guinea pig model.

PubMed

Chang, Mun Young; Gwon, Tae Mok; Lee, Ho Sun; Lee, Jun Ho; Oh, Seung Ha; Kim, Sung June; Park, Min-Hyun

2017-03-15

The present study aimed to evaluate the effects of systemic lipoic acid on hearing preservation after cochlear implantation. Twelve Dunkin-Hartley guinea pigs were randomly divided into two groups: the control group and the lipoic acid group. Animals in the lipoic acid group received lipoic acid intraperitoneally for 4 weeks. A sterilised silicone electrode-dummy was inserted through the round window to a depth of approximately 5 mm. The hearing level was measured using auditory brainstem responses (ABRs) prior to electrode-dummy insertion, and at 4 days and 1, 2, 3 and 4 weeks after electrode-dummy insertion. The threshold shift was defined as the difference between the pre-operative threshold and each of the post-operative thresholds. The cochleae were examined histologically 4 weeks after electrode-dummy insertion. Threshold shifts changed with frequency but not time. At 2kHz, ABR threshold shifts were statistically significantly lower in the lipoic acid group than the control group. At 8, 16 and 32kHz, there was no significant difference in the ABR threshold shift between the two groups. Histologic review revealed less intracochlear fibrosis along the electrode-dummy insertion site in the lipoic acid group than in the control group. The spiral ganglion cell densities of the basal, middle and apical turns were significantly higher in the lipoic acid group compared with the control group. Therefore, systemic lipoic acid administration appears to effectively preserve hearing at low frequencies in patients undergoing cochlear implantation. These effects may be attributed to the protection of spiral ganglion cells and prevention of intracochlear fibrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Monitoring the Hearing Handicap and the Recognition Threshold of Sentences of a Patient with Unilateral Auditory Neuropathy Spectrum Disorder with Use of a Hearing Aid

PubMed Central

Lima, Aline Patrícia; Mantello, Erika Barioni; Anastasio, Adriana Ribeiro Tavares

2015-01-01

Introduction Treatment for auditory neuropathy spectrum disorder (ANSD) is not yet well established, including the use of hearing aids (HAs). Not all patients diagnosed with ASND have access to HAs, and in some cases HAs are even contraindicated. Objective To monitor the hearing handicap and the recognition threshold of sentences in silence and in noise in a patient with ASND using an HA. Resumed Report A 47-year-old woman reported moderate sensorineural hearing loss in the right ear and high-frequency loss of 4 kHz in the left ear, with bilateral otoacoustic emissions. Auditory brainstem response suggested changes in the functioning of the auditory pathway (up to the inferior colliculus) on the right. An HA was indicated on the right. The patient was tested within a 3-month period before the HA fitting with respect to recognition threshold of sentences in quiet and in noise and for handicap determination. After HA use, she showed a 2.1-dB improvement in the recognition threshold of sentences in silence, a 6.0-dB improvement for recognition threshold of sentences in noise, and a rapid improvement of the signal-to-noise ratio from +3.66 to −2.4 dB when compared with the same tests before the fitting of the HA. Conclusion There was a reduction of the auditory handicap, although speech perception continued to be severely limited. There was a significant improvement of the recognition threshold of sentences in silence and in noise and of the signal-to-noise ratio after 3 months of HA use. PMID:27096026

Quadro-pulse stimulation is more effective than paired-pulse stimulation for plasticity induction of the human motor cortex.

PubMed

Hamada, Masashi; Hanajima, Ritsuko; Terao, Yasuo; Arai, Noritoshi; Furubayashi, Toshiaki; Inomata-Terada, Satomi; Yugeta, Akihiro; Matsumoto, Hideyuki; Shirota, Yuichiro; Ugawa, Yoshikazu

2007-12-01

Repetitive paired-pulse transcranial magnetic stimulation (TMS) at I-wave periodicity has been shown to induce a motor-evoked potential (MEP) facilitation. We hypothesized that a greater enhancement of motor cortical excitability is provoked by increasing the number of pulses per train beyond those by paired-pulse stimulation (PPS). We explored motor cortical excitability changes induced by repetitive application of trains of four monophasic magnetic pulses (quadro-pulse stimulation: QPS) at 1.5-ms intervals, repeated every 5s over the motor cortex projecting to the hand muscles. The aftereffects of QPS were evaluated with MEPs to a single-pulse TMS, motor threshold (MT), and responses to brain-stem stimulation. These effects were compared to those after PPS. To evaluate the QPS safety, we also studied the spread of excitation and after discharge using surface electromyograms (EMGs) of hand and arm muscles. Sizes of MEPs from the hand muscle were enhanced for longer than 75min after QPS; they reverted to the baseline at 90min. Responses to brain-stem stimulation from the hand muscle and cortical MEPs from the forearm muscle were unchanged after QPS over the hand motor area. MT was unaffected by QPS. No spreads of excitation were detected after QPS. The appearance rate of after discharges during QPS was not different from that during sham stimulation. Results show that QPS can safely induce long-lasting, topographically specific enhancement of motor cortical excitability. QPS is more effective than PPS for inducing motor cortical plasticity.

Protective effects of vitamins E, B and C and L-carnitine in the prevention of cisplatin-induced ototoxicity in rats.

PubMed

Tokgöz, S Alicura; Vuralkan, E; Sonbay, N D; Çalişkan, M; Saka, C; Beşalti, Ö; Akin, İ

2012-05-01

This experimental study aimed to investigate the effects of vitamins E, B and C and L-carnitine in preventing cisplatin-induced ototoxicity. Twenty-five adult, male, Wistar albino rats were randomly allocated to receive intraperitoneal cisplatin either alone or preceded by vitamins B, E or C or L-carnitine. Auditory brainstem response (i.e. hearing thresholds and wave I-IV intervals) and distortion product otoacoustic emissions (i.e. signal-to-noise ratios) were recorded before and 72 hours after cisplatin administration. The following statistically significant differences were seen: control group pre- vs post-treatment wave I-IV interval values (p < 0.05); control vs vitamin E and B groups' I-IV interval values (p < 0.05); control vs other groups' hearing thresholds; vitamin E vs vitamin B and C and L-carnitine groups' hearing thresholds (p < 0.05); and vitamin B vs vitamin C and L-carnitine groups' hearing thresholds (p < 0.05). Statistically significant decreases were seen when comparing the initial and final signal-to-noise ratios in the control, vitamin B and L-carnitine groups (2000 and 3000 Hz; p < 0.01), and the initial and final signal-to-noise ratios in the control group (at 4000 Hz; p < 0.01). Vitamins B, E and C and L-carnitine appear to reduce cisplatin-induced ototoxicity in rats. The use of such additional treatments to decrease cisplatin-induced ototoxicity in humans is still under discussion.

Inhalational exposure to carbonyl sulfide produces altered brainstem auditory and somatosensory-evoked potentials in Fischer 344N rats.

PubMed

Herr, David W; Graff, Jaimie E; Moser, Virginia C; Crofton, Kevin M; Little, Peter B; Morgan, Daniel L; Sills, Robert C

2007-01-01

Carbonyl sulfide (COS), a chemical listed by the original Clean Air Act, was tested for neurotoxicity by a National Institute of Environmental Health Sciences/National Toxicology Program and U.S. Environmental Protection Agency collaborative investigation. Previous studies demonstrated that COS produced cortical and brainstem lesions and altered auditory neurophysiological responses to click stimuli. This paper reports the results of expanded neurophysiological examinations that were an integral part of the previously published experiments (Morgan et al., 2004, Toxicol. Appl. Pharmacol. 200, 131-145; Sills et al., 2004, Toxicol. Pathol. 32, 1-10). Fisher 334N rats were exposed to 0, 200, 300, or 400 ppm COS for 6 h/day, 5 days/week for 12 weeks, or to 0, 300, or 400 ppm COS for 2 weeks using whole-body inhalation chambers. After treatment, the animals were studied using neurophysiological tests to examine: peripheral nerve function, somatosensory-evoked potentials (SEPs) (tail/hindlimb and facial cortical regions), brainstem auditory-evoked responses (BAERs), and visual flash-evoked potentials (2-week study). Additionally, the animals exposed for 2 weeks were examined using a functional observational battery (FOB) and response modification audiometry (RMA). Peripheral nerve function was not altered for any exposure scenario. Likewise, amplitudes of SEPs recorded from the cerebellum were not altered by treatment with COS. In contrast, amplitudes and latencies of SEPs recorded from cortical areas were altered after 12-week exposure to 400 ppm COS. The SEP waveforms were changed to a greater extent after forelimb stimulation than tail stimulation in the 2-week study. The most consistent findings were decreased amplitudes of BAER peaks associated with brainstem regions after exposure to 400 ppm COS. Additional BAER peaks were affected after 12 weeks, compared to 2 weeks of treatment, indicating that additional regions of the brainstem were damaged with longer exposures. The changes in BAERs were observed in the absence of altered auditory responsiveness in FOB or RMA. This series of experiments demonstrates that COS produces changes in brainstem auditory and cortical somatosensory neurophysiological responses that correlate with previously described histopathological damage.

The Auditory Brain-Stem Response to Complex Sounds: A Potential Biomarker for Guiding Treatment of Psychosis

PubMed Central

Tarasenko, Melissa A.; Swerdlow, Neal R.; Makeig, Scott; Braff, David L.; Light, Gregory A.

2014-01-01

Cognitive deficits limit psychosocial functioning in schizophrenia. For many patients, cognitive remediation approaches have yielded encouraging results. Nevertheless, therapeutic response is variable, and outcome studies consistently identify individuals who respond minimally to these interventions. Biomarkers that can assist in identifying patients likely to benefit from particular forms of cognitive remediation are needed. Here, we describe an event-related potential (ERP) biomarker – the auditory brain-stem response (ABR) to complex sounds (cABR) – that appears to be particularly well-suited for predicting response to at least one form of cognitive remediation that targets auditory information processing. Uniquely, the cABR quantifies the fidelity of sound encoded at the level of the brainstem and midbrain. This ERP biomarker has revealed auditory processing abnormalities in various neurodevelopmental disorders, correlates with functioning across several cognitive domains, and appears to be responsive to targeted auditory training. We present preliminary cABR data from 18 schizophrenia patients and propose further investigation of this biomarker for predicting and tracking response to cognitive interventions. PMID:25352811

Effects of alcohol and noise on temporary threshold shift in Guinea pigs.

PubMed

Liu, Tien-Chen; Hsu, Chuan-Jen; Hwang, Juen-Haur; Tseng, Fen-Yu; Chen, Yuh-Shyang

2004-01-01

The purpose of this study was to investigate the effects of concomitant exposure to noise and alcohol on the auditory thresholds. Twenty-four guinea pigs were equally divided into three groups: the acute intoxication group, the chronic intoxication group and the control group. Animals in the acute group received single intraperitoneal injections of ethanol (2 g/kg). In the chronic group, alcohol was administered via drinking water (10%, v/v) over a 60-day period. All animals were exposed to a white noise at the intensity of 105 dB A for 30 min. Auditory brainstem response (ABR) thresholds and distortion product otoacoustic emission (DPOAE) levels were measured before, immediately after noise exposure and also 1, 2, and 7 days following exposure. The results showed: first, acute alcohol injection caused a significant, temporary elevation of ABR threshold (4.8 dB in average), while chronic alcohol treatment did not change auditory threshold significantly. Second, noise exposure induced a mean threshold shift of 15.4- 19.7 dB. ABR threshold returned to normal 2 days after exposure. Both acute and chronic alcohol treatment did not alter the magnitude and time course of recovery of the temporary threshold shift (TTS). Third, the mean DPOAE amplitudes decreased at most frequencies following acute injection of alcohol. However, the differences did not reach statistical significance. Fourth, the mean DPOAE levels dropped 3.4-9.6 dB in all groups after noise exposure and returned to normal 1 day to 2 days after noise. There were no significant differences in the amount of DPOAE suppression after noise between the three groups. In summary, we have found that acute and chronic treatment of alcohol in combination with noise did not significantly exacerbate TTS or decrease DPOAE amplitudes relative to noise exposure alone. Copyright 2004 S. Karger AG, Basel

Tinnitus with a normal audiogram: Relation to noise exposure but no evidence for cochlear synaptopathy.

PubMed

Guest, Hannah; Munro, Kevin J; Prendergast, Garreth; Howe, Simon; Plack, Christopher J

2017-02-01

In rodents, exposure to high-level noise can destroy synapses between inner hair cells and auditory nerve fibers, without causing hair cell loss or permanent threshold elevation. Such "cochlear synaptopathy" is associated with amplitude reductions in wave I of the auditory brainstem response (ABR) at moderate-to-high sound levels. Similar ABR results have been reported in humans with tinnitus and normal audiometric thresholds, leading to the suggestion that tinnitus in these cases might be a consequence of synaptopathy. However, the ABR is an indirect measure of synaptopathy and it is unclear whether the results in humans reflect the same mechanisms demonstrated in rodents. Measures of noise exposure were not obtained in the human studies, and high frequency audiometric loss may have impacted ABR amplitudes. To clarify the role of cochlear synaptopathy in tinnitus with a normal audiogram, we recorded ABRs, envelope following responses (EFRs), and noise exposure histories in young adults with tinnitus and matched controls. Tinnitus was associated with significantly greater lifetime noise exposure, despite close matching for age, sex, and audiometric thresholds up to 14 kHz. However, tinnitus was not associated with reduced ABR wave I amplitude, nor with significant effects on EFR measures of synaptopathy. These electrophysiological measures were also uncorrelated with lifetime noise exposure, providing no evidence of noise-induced synaptopathy in this cohort, despite a wide range of exposures. In young adults with normal audiograms, tinnitus may be related not to cochlear synaptopathy but to other effects of noise exposure. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Comparison of threshold estimation in infants with hearing loss or normal hearing using auditory steady-state response evoked by narrow band CE-chirps and auditory brainstem response evoked by tone pips.

PubMed

Michel, Franck; Jørgensen, Kristoffer Foldager

2017-02-01

The objective of this study is to compare air-conduction thresholds obtained with ASSR evoked by narrow band (NB) CE-chirps and ABR evoked by tone pips (tpABR) in infants with various degrees of hearing loss. Thresholds were measured at 500, 1000, 2000 and 4000 Hz. Data on each participant were collected at the same day. Sixty-seven infants aged 4 d to 22 months (median age = 96 days), resulting in 57, 52, 87 and 56 ears for 500, 1000, 2000 and 4000 Hz, respectively. Statistical analysis was performed for ears with hearing loss (HL) and showed a very strong correlation between tpABR and ASSR evoked by NB CE-chirps: 0.90 (n = 28), 0.90 (n = 28), 0.96 (n = 42) and 0.95 (n = 30) for 500, 1000, 2000 and 4000 Hz, respectively. At these frequencies, the mean difference between tpABR and ASSR was -3.6 dB (± 7.0), -5.2 dB (± 7.3), -3.9 dB (± 5.2) and -5.2 dB (± 4.7). Linear regression analysis indicated that the relationship was not influenced by the degree of hearing loss. We propose that dB nHL to dB eHL correction values for ASSR evoked by NB CE-chirps should be 5 dB lower than values used for tpABR.

Ototoxicity in rats exposed to ethylbenzene and to two technical xylene vapours for 13 weeks.

PubMed

Gagnaire, François; Langlais, Cristina; Grossmann, Stéphane; Wild, Pascal

2007-02-01

Male Sprague-Dawley rats were exposed to ethylbenzene (200, 400, 600 and 800 ppm) and to two mixed xylenes (250, 500, 1,000 and 2,000 ppm total compounds) by inhalation, 6 h/day, 6 days/week for 13 weeks and sacrificed for morphological investigation 8 weeks after the end of exposure. Brainstem auditory-evoked responses were used to determine auditory thresholds at different frequencies. Ethylbenzene produced moderate to severe ototoxicity in rats exposed to the four concentrations studied. Increased thresholds were observed at 2, 4, 8 and 16 kHz in rats exposed to 400, 600 and 800 ppm ethylbenzene. Moderate to severe losses of outer hair cells of the organ of Corti occurred in animals exposed to the four concentrations studied. Exposure to both mixed xylenes produced ototoxicity characterized by increased auditory thresholds and losses of outer hair cells. Ototoxicity potentiation caused by ethylbenzene was observed. Depending on the mixed xylene studied and the area of the concentration-response curves taken into account, the concentrations of ethylbenzene in mixed xylenes necessary to cause a given ototoxicity were 1.7-2.8 times less than those of pure ethylbenzene. Given the high ototoxicity of ethylbenzene, the safety margin of less or equal to two (LOAEL/TWA) might be too small to protect workers from the potential risk of ototoxicity. Moreover, the enhanced ototoxicity of ethylbenzene and para-xylene observed in mixed xylenes should encourage the production of mixed xylenes with the lowest possible concentrations of ethylbenzene and para-xylene.

Dynamic modulation of decision biases by brainstem arousal systems.

PubMed

de Gee, Jan Willem; Colizoli, Olympia; Kloosterman, Niels A; Knapen, Tomas; Nieuwenhuis, Sander; Donner, Tobias H

2017-04-11

Decision-makers often arrive at different choices when faced with repeated presentations of the same evidence. Variability of behavior is commonly attributed to noise in the brain's decision-making machinery. We hypothesized that phasic responses of brainstem arousal systems are a significant source of this variability. We tracked pupil responses (a proxy of phasic arousal) during sensory-motor decisions in humans, across different sensory modalities and task protocols. Large pupil responses generally predicted a reduction in decision bias. Using fMRI, we showed that the pupil-linked bias reduction was (i) accompanied by a modulation of choice-encoding pattern signals in parietal and prefrontal cortex and (ii) predicted by phasic, pupil-linked responses of a number of neuromodulatory brainstem centers involved in the control of cortical arousal state, including the noradrenergic locus coeruleus. We conclude that phasic arousal suppresses decision bias on a trial-by-trial basis, thus accounting for a significant component of the variability of choice behavior.

Dynamic modulation of decision biases by brainstem arousal systems

PubMed Central

de Gee, Jan Willem; Colizoli, Olympia; Kloosterman, Niels A; Knapen, Tomas; Nieuwenhuis, Sander; Donner, Tobias H

2017-01-01

Decision-makers often arrive at different choices when faced with repeated presentations of the same evidence. Variability of behavior is commonly attributed to noise in the brain’s decision-making machinery. We hypothesized that phasic responses of brainstem arousal systems are a significant source of this variability. We tracked pupil responses (a proxy of phasic arousal) during sensory-motor decisions in humans, across different sensory modalities and task protocols. Large pupil responses generally predicted a reduction in decision bias. Using fMRI, we showed that the pupil-linked bias reduction was (i) accompanied by a modulation of choice-encoding pattern signals in parietal and prefrontal cortex and (ii) predicted by phasic, pupil-linked responses of a number of neuromodulatory brainstem centers involved in the control of cortical arousal state, including the noradrenergic locus coeruleus. We conclude that phasic arousal suppresses decision bias on a trial-by-trial basis, thus accounting for a significant component of the variability of choice behavior. DOI: http://dx.doi.org/10.7554/eLife.23232.001 PMID:28383284

Brainstem Correlates of Temporal Auditory Processing in Children with Specific Language Impairment

ERIC Educational Resources Information Center

Basu, Madhavi; Krishnan, Ananthanarayan; Weber-Fox, Christine

2010-01-01

Deficits in identification and discrimination of sounds with short inter-stimulus intervals or short formant transitions in children with specific language impairment (SLI) have been taken to reflect an underlying temporal auditory processing deficit. Using the sustained frequency following response (FFR) and the onset auditory brainstem responses…

Positron Emission Tomography in Cochlear Implant and Auditory Brainstem Implant Recipients.

ERIC Educational Resources Information Center

Miyamoto, Richard T.; Wong, Donald

2001-01-01

Positron emission tomography imaging was used to evaluate the brain's response to auditory stimulation, including speech, in deaf adults (five with cochlear implants and one with an auditory brainstem implant). Functional speech processing was associated with activation in areas classically associated with speech processing. (Contains five…

CHRONIC DIETARY EXPOSURE WITH INTERMITTENT SPIKE DOSES OF CHLORPYRIFOS FAILS TO ALTER BRAINSTEM AUDITORY EVOKED RESPONSE (BAERS) IN RATS.

EPA Science Inventory

Human exposure to pesticides is often characterized by chronic low level exposure with intermittent spiked higher exposures. Cholinergic transmission is involved in auditory structures in the periphery and the brainstem and is altered following chlorpyrifos exposure. This study e...

Age-Related Changes in Binaural Interaction at Brainstem Level.

PubMed

Van Yper, Lindsey N; Vermeire, Katrien; De Vel, Eddy F J; Beynon, Andy J; Dhooge, Ingeborg J M

2016-01-01

Age-related hearing loss hampers the ability to understand speech in adverse listening conditions. This is attributed to a complex interaction of changes in the peripheral and central auditory system. One aspect that may deteriorate across the lifespan is binaural interaction. The present study investigates binaural interaction at the level of the auditory brainstem. It is hypothesized that brainstem binaural interaction deteriorates with advancing age. Forty-two subjects of various age participated in the study. Auditory brainstem responses (ABRs) were recorded using clicks and 500 Hz tone-bursts. ABRs were elicited by monaural right, monaural left, and binaural stimulation. Binaural interaction was investigated in two ways. First, grand averages of the binaural interaction component were computed for each age group. Second, wave V characteristics of the binaural ABR were compared with those of the summed left and right ABRs. Binaural interaction in the click ABR was demonstrated by shorter latencies and smaller amplitudes in the binaural compared with the summed monaural responses. For 500 Hz tone-burst ABR, no latency differences were found. However, amplitudes were significantly smaller in the binaural than summed monaural condition. An age-effect was found for 500 Hz tone-burst, but not for click ABR. Brainstem binaural interaction seems to decline with age. Interestingly, these changes seem to be stimulus-dependent.

Click-evoked auditory brainstem responses and autism spectrum disorder: A meta-analytic review.

PubMed

Talge, Nicole M; Tudor, Brooke M; Kileny, Paul R

2018-06-01

Behavior does not differentiate ASD risk prior to 12 months of age, but biomarkers may inform risk before symptoms emerge. Click-evoked auditory brainstem responses (ABRs) may be worth consideration due to their measurement properties (noninvasiveness; reliability) and conceptual features (well-characterized neural generators), but participant characteristics and assessment protocols vary considerably across studies. Our goal is to perform a meta-analysis of the association between ABRs and ASD. Following an electronic database search (PubMed, Medline, PsycInfo, PsycArticles), we included papers that were written in English, included ASD and typically-developing (TD) groups, and reported the information needed to calculate standardized mean differences (Hedges's g) for at least one ABR latency component (I, III, V, I-III, III-V, I-V). We weighted and averaged effect sizes across conditions and subsets of participants to yield one estimate per component per study. We then performed random-effects regressions to generate component-specific estimates. ASD was associated with longer ABR latencies for Waves III (g = 0.5, 95% CI 0.1, 0.9), V (g = 0.7, 95% CI 0.3, 1.1), I-III (g = 0.7, 95% CI 0.2, 1.2), and I-V (g = 0.6, 95% CI 0.2, 1.0). All components showed significant heterogeneity. Associations were strongest among participants ≤8 years of age and those without middle ear abnormalities or elevated auditory thresholds. In sum, associations between ABRs and ASD are medium-to-large in size, but exhibit heterogeneity. Identifying sources of heterogeneity is challenging, however, due to power limitations and co-occurrence of sample/design characteristics across studies. Research addressing the above limitations is crucial to determining the etiologic and/or prognostic value of ABRs for ASD. Autism Res 2018, 11: 916-927. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. Auditory brainstem responses (ABR) may be associated with ASD, but participant characteristics and assessment protocols vary considerably across individual studies. Our goal is to combine the results across these studies to facilitate clarity on the topic. Doing so represents a first step in evaluating whether ABRs yield potential for informing the etiology of ASD risk and/or ASD symptom profiles. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

Minocycline attenuates noise-induced hearing loss in rats.

PubMed

Zhang, Jing; Song, Yong-Li; Tian, Ke-Yong; Qiu, Jian-Hua

2017-02-03

Noise-induced hearing loss (NIHL) is a serious health concern and prevention of hair cell death or therapeutic intervention at the early stage of NIHL is critical to preserve hearing. Minocycline is a semi-synthetic derivative of tetracycline and has been shown to have otoprotective effects in ototoxic drug-induced hearing impairment, however, whether minocycline can protect against NIHL has not been investigated. The present study demonstrated elevated ABR (auditory brainstem response) thresholds and outer hair cell loss following traumatic noise exposure, which was mitigated by intraperitoneal administration of minocycline (45mg/kg/d) for 5 consecutive days. In conclusion, the present study demonstrated that minocycline, a clinically approved drug with a good safety profile, can attenuate NIHL in rats and may potentially be used for treatment of hearing loss in clinic. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Exposures to fine particulate matter (PM2.5) and ozone above USA standards are associated with auditory brainstem dysmorphology and abnormal auditory brainstem evoked potentials in healthy young dogs.

PubMed

Calderón-Garcidueñas, Lilian; González-González, Luis O; Kulesza, Randy J; Fech, Tatiana M; Pérez-Guillé, Gabriela; Luna, Miguel Angel Jiménez-Bravo; Soriano-Rosales, Rosa Eugenia; Solorio, Edelmira; Miramontes-Higuera, José de Jesús; Gómez-Maqueo Chew, Aline; Bernal-Morúa, Alexia F; Mukherjee, Partha S; Torres-Jardón, Ricardo; Mills, Paul C; Wilson, Wayne J; Pérez-Guillé, Beatriz; D'Angiulli, Amedeo

2017-10-01

Delayed central conduction times in the auditory brainstem have been observed in Mexico City (MC) healthy children exposed to fine particulate matter (PM 2.5 ) and ozone (O 3 ) above the current United States Environmental Protection Agency (US-EPA) standards. MC children have α synuclein brainstem accumulation and medial superior olivary complex (MSO) dysmorphology. The present study used a dog model to investigate the potential effects of air pollution on the function and morphology of the auditory brainstem. Twenty-four dogs living in clean air v MC, average age 37.1 ± 26.3 months, underwent brainstem auditory evoked potential (BAEP) measurements. Eight dogs (4 MC, 4 Controls) were analysed for auditory brainstem morphology and histopathology. MC dogs showed ventral cochlear nuclei hypotrophy and MSO dysmorphology with a significant decrease in cell body size, decreased neuronal packing density with regions in the nucleus devoid of neurons and marked gliosis. MC dogs showed significant delayed BAEP absolute wave I, III and V latencies compared to controls. MC dogs show auditory nuclei dysmorphology and BAEPs consistent with an alteration of the generator sites of the auditory brainstem response waveform. This study puts forward the usefulness of BAEPs to study auditory brainstem neurodegenerative changes associated with air pollution in dogs. Recognition of the role of non-invasive BAEPs in urban dogs is warranted to elucidate novel neurodegenerative pathways link to air pollution and a promising early diagnostic strategy for Alzheimer's Disease. Copyright © 2017 Elsevier Inc. All rights reserved.

Piracetam-induced changes on the brainstem auditory response in anesthetized juvenile rhesus monkeys (Macaca mulatta). Report of two clinical cases.

PubMed

Durand-Rivera, A; Gonzalez-Pina, R; Hernandez-Godinez, B; Ibanez-Contreras, A; Bueno-Nava, A; Alfaro-Rodriguez, A

2012-10-01

We describe two clinical cases and examine the effects of piracetam on the brainstem auditory response in infantile female rhesus monkeys (Macaca mulatta). We found that the interwave intervals show a greater reduction in a 3-year-old rhesus monkey compared to a 1-year-old rhesus monkey. In this report, we discuss the significance of these observations. © 2012 John Wiley & Sons A/S.

Short-wavelength infrared laser activates the auditory neurons: comparing the effect of 980 vs. 810 nm wavelength.

PubMed

Tian, Lan; Wang, Jingxuan; Wei, Ying; Lu, Jianren; Xu, Anting; Xia, Ming

2017-02-01

Research on auditory neural triggering by optical stimulus has been developed as an emerging technique to elicit the auditory neural response, which may provide an alternative method to the cochlear implants. However, most previous studies have been focused on using longer-wavelength near-infrared (>1800 nm) laser. The effect comparison of different laser wavelengths in short-wavelength infrared (SWIR) range on the auditory neural stimulation has not been previously explored. In this study, the pulsed 980- and 810-nm SWIR lasers were applied as optical stimuli to irradiate the auditory neurons in the cochlea of five deafened guinea pigs and the neural response under the two laser wavelengths was compared by recording the evoked optical auditory brainstem responses (OABRs). In addition, the effect of radiant exposure, laser pulse width, and threshold with the two laser wavelengths was further investigated and compared. The one-way analysis of variance (ANOVA) was used to analyze those data. Results showed that the OABR amplitude with the 980-nm laser is higher than the amplitude with the 810-nm laser under the same radiant exposure from 10 to 102 mJ/cm 2 . And the laser stimulation of 980 nm wavelength has lower threshold radiant exposure than the 810 nm wavelength at varied pulse duration in 20-500 μs range. Moreover, the 810-nm laser has a wider optimized pulse duration range than the 980-nm laser for the auditory neural stimulation.

Developmental exposure to an environmental PCB mixture delays the propagation of electrical kindling from the amygdala.

PubMed

Bandara, Suren B; Sadowski, Renee N; Schantz, Susan L; Gilbert, Mary E

2017-01-01

Developmental PCB exposure impairs hearing and induces brainstem audiogenic seizures in adult offspring. The degree to which this enhanced susceptibility to seizure is manifest in other brain regions has not been examined. Thus, electrical kindling of the amygdala was used to evaluate the effect of developmental exposure to an environmentally relevant PCB mixture on seizure susceptibility in the rat. Female Long-Evans rats were dosed orally with 0 or 6mg/kg/day of the PCB mixture dissolved in corn oil vehicle 4 weeks prior to mating and continued through gestation and up until postnatal day (PND) 21. On PND 21, pups were weaned, and two males from each litter were randomly selected for the kindling study. As adults, the male rats were implanted bilaterally with electrodes in the basolateral amygdala. For each animal, afterdischarge (AD) thresholds in the amygdala were determined on the first day of testing followed by once daily stimulation at a standard 200μA stimulus intensity until three stage 5 generalized seizures (GS) ensued. Developmental PCB exposure did not affect the AD threshold or total cumulative AD duration, but PCB exposure did increase the latency to behavioral manifestations of seizure propagation. PCB exposed animals required significantly more stimulations to reach stage 2 seizures compared to control animals, indicating attenuated focal (amygdala) excitability. A delay in kindling progression in the amygdala stands in contrast to our previous finding of increased susceptibility to brainstem-mediated audiogenic seizures in PCB-exposed animals in response to a an intense auditory stimulus. These seemingly divergent results are not unexpected given the distinct source, type, and mechanistic underpinnings of these different seizure models. A delay in epileptogenesis following focal amygdala stimulation may reflect a decrease in neuroplasticity following developmental PCB exposure consistent with reductions in use-dependent synaptic plasticity that have been reported in the hippocampus of developmentally PCB exposed animals. Copyright © 2016 Elsevier B.V. All rights reserved.

The Effect of Otitis Media with Effusion on the Masking-Level Difference and the Auditory Brainstem Response.

ERIC Educational Resources Information Center

Hall, Joseph W.; Grose, John H.

1993-01-01

This study of 14 children (ages 5-9) with a history of otitis media with effusion found that subjects had significantly reduced masking-level differences (MLD) compared to controls. Results suggest that the reduction in MLD may be related to abnormal brainstem processing. (Author/JDD)

Electrophysiological Evidence for the Sources of the Masking Level Difference

ERIC Educational Resources Information Center

Fowler, Cynthia G.

2017-01-01

Purpose: The purpose of this review article is to review evidence from auditory evoked potential studies to describe the contributions of the auditory brainstem and cortex to the generation of the masking level difference (MLD). Method: A literature review was performed, focusing on the auditory brainstem, middle, and late latency responses used…

CO2-evoked release of PGE2 modulates sighs and inspiration as demonstrated in brainstem organotypic culture

PubMed Central

Forsberg, David; Horn, Zachi; Tserga, Evangelia; Smedler, Erik; Silberberg, Gilad; Shvarev, Yuri; Kaila, Kai; Uhlén, Per; Herlenius, Eric

2016-01-01

Inflammation-induced release of prostaglandin E2 (PGE2) changes breathing patterns and the response to CO2 levels. This may have fatal consequences in newborn babies and result in sudden infant death. To elucidate the underlying mechanisms, we present a novel breathing brainstem organotypic culture that generates rhythmic neural network and motor activity for 3 weeks. We show that increased CO2 elicits a gap junction-dependent release of PGE2. This alters neural network activity in the preBötzinger rhythm-generating complex and in the chemosensitive brainstem respiratory regions, thereby increasing sigh frequency and the depth of inspiration. We used mice lacking eicosanoid prostanoid 3 receptors (EP3R), breathing brainstem organotypic slices and optogenetic inhibition of EP3R+/+ cells to demonstrate that the EP3R is important for the ventilatory response to hypercapnia. Our study identifies a novel pathway linking the inflammatory and respiratory systems, with implications for inspiration and sighs throughout life, and the ability to autoresuscitate when breathing fails. DOI: http://dx.doi.org/10.7554/eLife.14170.001 PMID:27377173

Block-Dependent Sedation during Epidural Anaesthesia is Associated with Delayed Brainstem Conduction

PubMed Central

Wadhwa, Anupama; Shah, Yunus M.; Lin, Chum-Ming; Haugh, Gilbert S.; Sessler, Daniel I.

2005-01-01

Neuraxial anaesthesia produces a sedative and anesthetic-sparing effect. Recent evidence suggests that spinal cord anaesthesia modifies reticulo-thalamo-cortical arousal by decreasing afferent sensory transmission. We hypothesized that epidural anaesthesia produces sensory deafferentation-dependent sedation that is associated with impairment of brainstem transmission. We used brainstem auditory evoked potentials (BAEP) to evaluate reticular function in 11 volunteers. Epidural anaesthesia was induced with 2% 2-chloroprocaine. Hemodynamic and respiratory responses, sensory block level, sedation depth and BAEP were assessed throughout induction and resolution of epidural anaesthesia. Sedation was evaluated using verbal rating score (VRS), observer's assessment alertness/sedation (OAA/S) score, and bispectral index (BIS). Prediction probability (PK) was used to associate sensory block with sedation, as well as BIS with other sedation measures. Spearman rank order correlation was used to associate block level and sedation with the absolute and interpeak BAEP latencies. Sensory block level significantly predicted VRS (PK = 0.747), OAA/S score (PK = 0.748) and BIS. Bispectral index predicted VRS and OAA/S score (PK = 0.728). The latency of wave III of BAEP significantly correlated with sedation level (rho = 0.335, P < 0.01) and sensory block (rho = 0.394, P < 0.01). The other BAEP parameters did not change during epidural anaesthesia. Hemodynamic and respiratory responses remained stable throughout the study. Sedation during epidural anaesthesia depends on sensory block level and is associated with detectable block-dependent alterations in the brainstem auditory evoked responses. Sensory deafferentation may reduce CNS alertness through mechanisms related to brainstem neural activity. PMID:15220178

Ear asymmetries in middle-ear, cochlear, and brainstem responses in human infants

PubMed Central

Keefe, Douglas H.; Gorga, Michael P.; Jesteadt, Walt; Smith, Lynette M.

2008-01-01

In 2004, Sininger and Cone-Wesson examined asymmetries in the signal-to-noise ratio (SNR) of otoacoustic emissions (OAE) in infants, reporting that distortion-product (DP)OAE SNR was larger in the left ear, whereas transient-evoked (TE)OAE SNR was larger in the right. They proposed that cochlear and brainstem asymmetries facilitate development of brain-hemispheric specialization for sound processing. Similarly, in 2006 Sininger and Cone-Wesson described ear asymmetries mainly favoring the right ear in infant auditory brainstem responses (ABRs). The present study analyzed 2640 infant responses to further explore these effects. Ear differences in OAE SNR, signal, and noise were evaluated separately and across frequencies (1.5, 2, 3, and 4 kHz), and ABR asymmetries were compared with cochlear asymmetries. Analyses of ear-canal reflectance and admittance showed that asymmetries in middle-ear functioning did not explain cochlear and brainstem asymmetries. Current results are consistent with earlier studies showing right-ear dominance for TEOAE and ABR. Noise levels were higher in the right ear for OAEs and ABRs, causing ear asymmetries in SNR to differ from those in signal level. No left-ear dominance for DPOAE signal was observed. These results do not support a theory that ear asymmetries in cochlear processing mimic hemispheric brain specialization for auditory processing. PMID:18345839

Vestibular Evoked Myogenic Potentials in Normal Mice and Phex Mice With Spontaneous Endolymphatic Hydrops

PubMed Central

Sheykholeslami, Kianoush; Megerian, Cliff A.; Zheng, Qing Y.

2010-01-01

Objective and Background Vestibular evoked myogenic potentials (VEMPs) have been recorded from the neck musculature and the cervical spinal cord in humans and a limited number of laboratory animals in response to loud sound. However, the mouse VEMP has yet to be described. Evaluation of the sacculocollic pathway via VEMPs in mice can set the stage for future evaluations of mutant mice that now play an important role in research regarding human auditory and vestibular dysfunction. Materials and Methods Sound-evoked potentials were recorded from the neck extensor muscles and the cervical spinal cord in normal adult mice and in circling PhexHyp-Duk/y mice with known vestibular abnormalities, including endolymphatic hydrops (ELH). Results Biphasic potentials were recorded from all normal animals. The mean threshold of the VEMP response in normal adult mice was 60 dB normal hearing level with a mean peak latency of 6.25 ± 0.46 and 7.95 ± 0.42 milliseconds for p1 and n1 peaks, respectively. At the maximum sound intensity used (100 dB normal hearing level), 4 of 5 Phex mice did not exhibit VEMP responses, and 1 showed an elevated threshold, but normal response, with regard to peak latency and amplitude. The histologic findings in all of these Phex mice were consistent with distended membranous labyrinth, displaced Reissner membrane, ganglion cell loss, and ELH. Conclusion This is the first report of VEMP recordings in mice and the first report of abnormal VEMPs in a mouse model with ELH. The characteristics of these potentials such as higher response threshold in comparison to auditory brainstem response, myogenic nature of the response, and latency correlation with the cervical recording (accessory nerve nucleus) were similar to those of VEMPs in humans, guinea pigs, cats, and rats, suggesting that the mouse may be used as an animal model in the study of VEMPs. The simplicity and reliability of these recordings make the VEMP a uniquely informative test for assessing vestibular function, and these results suggest that they may be informative in mice with various mutations. However, further investigation is necessary. PMID:19300299

Effect of low-level laser treatment on cochlea hair-cell recovery after ototoxic hearing loss

NASA Astrophysics Data System (ADS)

Rhee, Chung-Ku; He, Peijie; Jung, Jae Yun; Ahn, Jin-Chul; Chung, Phil-Sang; Lee, Min Young; Suh, Myung-Whan

2013-12-01

The primary cause of hearing loss includes damage to cochlear hair cells. Low-level laser therapy (LLLT) has become a popular treatment for damaged nervous systems. Based on the idea that cochlea hair cells and neural cells are from same developmental origin, the effect of LLLT on hearing loss in animal models is evaluated. Hearing loss animal models were established, and the animals were irradiated by 830-nm diode laser once a day for 10 days. Power density of the laser treatment was 900 mW/cm2, and the fluence was 162 to 194 J. The tympanic membrane was evaluated after LLLT. Thresholds of auditory brainstem responses were evaluated before treatment, after gentamicin, and after 10 days of LLLT. Quantitative scanning electron microscopic (SEM) observations were done by counting remaining hair cells. Tympanic membranes were intact at the end of the experiment. No adverse tissue reaction was found. On SEM images, LLLT significantly increased the number of hair cells in middle and basal turns. Hearing was significantly improved by laser irradiation. After LLLT treatment, both the hearing threshold and hair-cell count significantly improved.

Therapeutic value of nerve growth factor in promoting neural stem cell survival and differentiation and protecting against neuronal hearing loss.

PubMed

Han, Zhao; Wang, Cong-Pin; Cong, Ning; Gu, Yu-Yan; Ma, Rui; Chi, Fang-Lu

2017-04-01

Nerve growth factor (NGF) is a neurotrophic factor that modulates survival and differentiation of neural stem cells (NSCs). We investigated the function of NGF in promoting growth and neuronal differentiation of NSCs isolated from mouse cochlear tissue, as well as its protective properties against gentamicin (GMC) ototoxicity. NSCs were isolated from the cochlea of mice and cultured in vitro. Effect of NGF on survival, neurosphere formation, and differentiation of the NSCs, as well as neurite outgrowth and neural excitability in the subsequent in vitro neuronal network, was examined. Mechanotransduction capacity of intact cochlea and auditory brainstem response (ABR) threshold in mice were also measured following GMC treatment to evaluate protection using NGF against GMC-induced neuronal hearing loss. NGF improved survival, neurosphere formation, and neuronal differentiation of mouse cochlear NSCs in vitro, as well as promoted neurite outgrowth and neural excitability in the NSC-differentiated neuronal culture. In addition, NGF protected mechanotransduction capacity and restored ABR threshold in gentamicin ototoxicity mouse model. Our study supports a potential therapeutic value of NGF in promoting proliferation and differentiation of NSCs into functional neurons in vitro, supporting its protective role in the treatment of neuronal hearing loss.

Pathophysiology of the inner ear after blast injury caused by laser-induced shock wave

PubMed Central

Niwa, Katsuki; Mizutari, Kunio; Matsui, Toshiyasu; Kurioka, Takaomi; Matsunobu, Takeshi; Kawauchi, Satoko; Satoh, Yasushi; Sato, Shunichi; Shiotani, Akihiro; Kobayashi, Yasushi

2016-01-01

The ear is the organ that is most sensitive to blast overpressure, and ear damage is most frequently seen after blast exposure. Blast overpressure to the ear results in sensorineural hearing loss, which is untreatable and is often associated with a decline in the quality of life. In this study, we used a rat model to demonstrate the pathophysiological and structural changes in the inner ear that replicate pure sensorineural hearing loss associated with blast injury using laser-induced shock wave (LISW) without any conductive hearing loss. Our results indicate that threshold elevation of the auditory brainstem response (ABR) after blast exposure was primarily caused by outer hair cell dysfunction induced by stereociliary bundle disruption. The bundle disruption pattern was unique; disturbed stereocilia were mostly observed in the outermost row, whereas those in the inner and middle rows stereocilia remained intact. In addition, the ABR examination showed a reduction in wave I amplitude without elevation of the threshold in the lower energy exposure group. This phenomenon was caused by loss of the synaptic ribbon. This type of hearing dysfunction has recently been described as hidden hearing loss caused by cochlear neuropathy, which is associated with tinnitus or hyperacusis. PMID:27531021

Randomized, Prospective, Three-Arm Study to Confirm the Auditory Safety and Efficacy of Artemether-Lumefantrine in Colombian Patients with Uncomplicated Plasmodium falciparum Malaria

PubMed Central

Carrasquilla, Gabriel; Barón, Clemencia; Monsell, Edwin M.; Cousin, Marc; Walter, Verena; Lefèvre, Gilbert; Sander, Oliver; Fisher, Laurel M.

2012-01-01

The safety of artemether-lumefantrine in patients with acute, uncomplicated Plasmodium falciparum malaria was investigated prospectively using the auditory brainstem response (ABR) and pure-tone thresholds. Secondary outcomes included polymerase chain reaction-corrected cure rates. Patients were randomly assigned in a 3:1:1 ratio to either artemether-lumefantrine (N = 159), atovaquone-proguanil (N = 53), or artesunate-mefloquine (N = 53). The null hypothesis (primary outcome), claiming that the percentage of patients with a baseline to Day-7 ABR Wave III latency increase of > 0.30 msec is ≥ 15% after administration of artemether-lumefantrine, was rejected; 2.6% of patients (95% confidence interval: 0.7–6.6) exceeded 0.30 msec, i.e., significantly below 15% (P < 0.0001). A model-based analysis found no apparent relationship between drug exposure and ABR change. In all three groups, average improvements (2–4 dB) in pure-tone thresholds were observed, and polymerase chain reaction-corrected cure rates were > 95% to Day 42. The results support the continued safe and efficacious use of artemether-lumefantrine in uncomplicated falciparum malaria. PMID:22232454

Randomized, prospective, three-arm study to confirm the auditory safety and efficacy of artemether-lumefantrine in Colombian patients with uncomplicated Plasmodium falciparum malaria.

PubMed

Carrasquilla, Gabriel; Barón, Clemencia; Monsell, Edwin M; Cousin, Marc; Walter, Verena; Lefèvre, Gilbert; Sander, Oliver; Fisher, Laurel M

2012-01-01

The safety of artemether-lumefantrine in patients with acute, uncomplicated Plasmodium falciparum malaria was investigated prospectively using the auditory brainstem response (ABR) and pure-tone thresholds. Secondary outcomes included polymerase chain reaction-corrected cure rates. Patients were randomly assigned in a 3:1:1 ratio to either artemether-lumefantrine (N = 159), atovaquone-proguanil (N = 53), or artesunate-mefloquine (N = 53). The null hypothesis (primary outcome), claiming that the percentage of patients with a baseline to Day-7 ABR Wave III latency increase of > 0.30 msec is ≥ 15% after administration of artemether-lumefantrine, was rejected; 2.6% of patients (95% confidence interval: 0.7-6.6) exceeded 0.30 msec, i.e., significantly below 15% (P < 0.0001). A model-based analysis found no apparent relationship between drug exposure and ABR change. In all three groups, average improvements (2-4 dB) in pure-tone thresholds were observed, and polymerase chain reaction-corrected cure rates were > 95% to Day 42. The results support the continued safe and efficacious use of artemether-lumefantrine in uncomplicated falciparum malaria.

The protective effect of olfactory ensheathing cells on post-injury spiral ganglion cells.

PubMed

Dai, Qi; Zhang, Zhicun; Liu, Quan; Yu, Hongmeng

2016-11-01

Transplantation of OECs into the cochlea may protect and increase the survival of SGCs. To investigate the protective effect of the transplantation of olfactory ensheathing cells (OECs) on injured spiral ganglion cells (SGCs) in rats. OECs were transplanted into the cochlea in rats with SGCs that were injured by kanamycin sulfate (KM). An equal volume of D-Hanks was injected into the cochlea of control rats. Auditory brainstem responses (ABRs) were recorded from the rats in both groups to monitor changes in hearing thresholds. Immunofluorescence was employed to examine the density and morphology of SGCs to assess the ototoxic condition of the cochlea. There was no significant difference in the ABR threshold at each frequency between the control and experimental groups. Notably, in the experimental group, a number of Hoechst 3334-labeled nuclei were detected from the apex to the basal turn of the cochlea, demonstrating that the OECs were successfully transplanted and survived in the cochlea. In the experimental group, most of the SGCs were tightly arranged, and the nuclear membrane, chromatin, and nucleolus were all clear. The SGCs in the control group were loosely arranged, and only a few normal SGCs were observed in this group.

Pathophysiology of the inner ear after blast injury caused by laser-induced shock wave.

PubMed

Niwa, Katsuki; Mizutari, Kunio; Matsui, Toshiyasu; Kurioka, Takaomi; Matsunobu, Takeshi; Kawauchi, Satoko; Satoh, Yasushi; Sato, Shunichi; Shiotani, Akihiro; Kobayashi, Yasushi

2016-08-17

The ear is the organ that is most sensitive to blast overpressure, and ear damage is most frequently seen after blast exposure. Blast overpressure to the ear results in sensorineural hearing loss, which is untreatable and is often associated with a decline in the quality of life. In this study, we used a rat model to demonstrate the pathophysiological and structural changes in the inner ear that replicate pure sensorineural hearing loss associated with blast injury using laser-induced shock wave (LISW) without any conductive hearing loss. Our results indicate that threshold elevation of the auditory brainstem response (ABR) after blast exposure was primarily caused by outer hair cell dysfunction induced by stereociliary bundle disruption. The bundle disruption pattern was unique; disturbed stereocilia were mostly observed in the outermost row, whereas those in the inner and middle rows stereocilia remained intact. In addition, the ABR examination showed a reduction in wave I amplitude without elevation of the threshold in the lower energy exposure group. This phenomenon was caused by loss of the synaptic ribbon. This type of hearing dysfunction has recently been described as hidden hearing loss caused by cochlear neuropathy, which is associated with tinnitus or hyperacusis.

TEN DAY EXPOSURES TO CARBONYL SULFIDE PRODUCE BRAINSTEM LESIONS AND CHANGES IN BRAINSTEM AUDITORY EVOKED RESPONSES IN FISCHER 344N RATS.

EPA Science Inventory

Carbonyl sulfide (COS) is a chemical intermediate in the production of pesticides and herbicides, a metabolite of carbon disulfide, a byproduct of the combustion of organic material, and a naturally occurring compound. COS was included in a Toxic Substances Control Act request fo...

Musicians and Tone-Language Speakers Share Enhanced Brainstem Encoding but Not Perceptual Benefits for Musical Pitch

ERIC Educational Resources Information Center

Bidelman, Gavin M.; Gandour, Jackson T.; Krishnan, Ananthanarayan

2011-01-01

Behavioral and neurophysiological transfer effects from music experience to language processing are well-established but it is currently unclear whether or not linguistic expertise (e.g., speaking a tone language) benefits music-related processing and its perception. Here, we compare brainstem responses of English-speaking musicians/non-musicians…

Effects of acute brainstem compression on auditory brainstem response in the guinea pig.

PubMed

Tu, T Y; Yu, L H; Chiu, J H; Shu, C H; Shiao, A S; Lien, C F

1998-11-01

The purpose of this study was to establish the norm for parameters of auditory brainstem response (ABR) in the guinea pig and to investigate if acute brainstem compression results in significant changes to these parameters. Thirty-six guinea pigs with positive Preyer's reflex were anesthetized. A craniectomy was performed to remove the right occipital bone and the dura mater was opened to expose the brain, cerebellum and cerebellopontine angle (CPA). A small inflatable balloon was placed into the CPA precisely and slowly. ABR was recorded before incision of the skin as a baseline value, after placement and after inflation of the balloon with water at 0.1-ml intervals. Five stable peaks were recorded in 27 experimental animals. When the balloon was inflated with 0.1 ml water, the absolute latency (AL) of peaks IV and V and the interpeak latency (IPL) of peaks III and IV, and IV and V were prolonged. The amplitude ratios (AR) of peaks II, III, IV and V to peak I decreased. Inflation of the balloon with 0.2 ml of water caused further elongation of ALs of peaks IV and V and decreases in each AR. When the balloon volume increased to 0.3 ml, peak V became unrecognizable and peaks III and IV showed significant elongation of AL; peaks I and II did not show significant change in ALs. Further increase of the balloon volume to 0.4 ml resulted in disappearance of peaks III, IV and V; AL of peak II was also elongated. However, the amplitude and AL of peak I remained unchanged. Similar changes were observed in IPLs. This study establishes the norm of parameters of ABR in guinea pigs and demonstrates that acute brainstem compression causes elongation of ALs and IPLs of peaks II, III, IV and V. This suggests that peaks II, III, IV and V come from the brainstem and that peak I is not generated from the brainstem in the guinea pig.

Encoding of speech sounds at auditory brainstem level in good and poor hearing aid performers.

PubMed

Shetty, Hemanth Narayan; Puttabasappa, Manjula

Hearing aids are prescribed to alleviate loss of audibility. It has been reported that about 31% of hearing aid users reject their own hearing aid because of annoyance towards background noise. The reason for dissatisfaction can be located anywhere from the hearing aid microphone till the integrity of neurons along the auditory pathway. To measure spectra from the output of hearing aid at the ear canal level and frequency following response recorded at the auditory brainstem from individuals with hearing impairment. A total of sixty participants having moderate sensorineural hearing impairment with age range from 15 to 65 years were involved. Each participant was classified as either Good or Poor Hearing aid Performers based on acceptable noise level measure. Stimuli /da/ and /si/ were presented through loudspeaker at 65dB SPL. At the ear canal, the spectra were measured in the unaided and aided conditions. At auditory brainstem, frequency following response were recorded to the same stimuli from the participants. Spectrum measured in each condition at ear canal was same in good hearing aid performers and poor hearing aid performers. At brainstem level, better F 0 encoding; F 0 and F 1 energies were significantly higher in good hearing aid performers than in poor hearing aid performers. Though the hearing aid spectra were almost same between good hearing aid performers and poor hearing aid performers, subtle physiological variations exist at the auditory brainstem. The result of the present study suggests that neural encoding of speech sound at the brainstem level might be mediated distinctly in good hearing aid performers from that of poor hearing aid performers. Thus, it can be inferred that subtle physiological changes are evident at the auditory brainstem in a person who is willing to accept noise from those who are not willing to accept noise. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Speech Evoked Auditory Brainstem Response in Stuttering

PubMed Central

Tahaei, Ali Akbar; Ashayeri, Hassan; Pourbakht, Akram; Kamali, Mohammad

2014-01-01

Auditory processing deficits have been hypothesized as an underlying mechanism for stuttering. Previous studies have demonstrated abnormal responses in subjects with persistent developmental stuttering (PDS) at the higher level of the central auditory system using speech stimuli. Recently, the potential usefulness of speech evoked auditory brainstem responses in central auditory processing disorders has been emphasized. The current study used the speech evoked ABR to investigate the hypothesis that subjects with PDS have specific auditory perceptual dysfunction. Objectives. To determine whether brainstem responses to speech stimuli differ between PDS subjects and normal fluent speakers. Methods. Twenty-five subjects with PDS participated in this study. The speech-ABRs were elicited by the 5-formant synthesized syllable/da/, with duration of 40 ms. Results. There were significant group differences for the onset and offset transient peaks. Subjects with PDS had longer latencies for the onset and offset peaks relative to the control group. Conclusions. Subjects with PDS showed a deficient neural timing in the early stages of the auditory pathway consistent with temporal processing deficits and their abnormal timing may underlie to their disfluency. PMID:25215262

[Investigation of neural stem cell-derived donor contribution in the inner ear following blastocyst injection].

PubMed

Volkenstein, S; Brors, D; Hansen, S; Mlynski, R; Dinger, T C; Müller, A M; Dazert, S

2008-03-01

Utilising the enormous proliferation and multi-lineage differentiation potentials of somatic stem cells represents a possible therapeutical strategy for diseases of non-regenerative tissues like the inner ear. In the current study, the possibility of murine neural stem cells to contribute to the developing inner ear following blastocyst injection was investigated. Fetal brain-derived neural stem cells from the embryonic day 14 cortex of male mice were isolated and expanded for four weeks in neurobasal media supplemented with bFGF and EGF. Neural stem cells of male animals were harvested, injected into blastocysts and the blastocysts were transferred into pseudo-pregnant foster animals. Each blastocyst was injected with 5-15 microspheres growing from single cell suspension from neurospheres dissociated the day before. The resulting mice were investigated six months POST PARTUM for the presence of donor cells. Brainstem evoked response audiometry (BERA) was performed in six animals. To visualize donor cells Lac-Z staining was performed on sliced cochleas of two animals. In addition, the cochleas of four female animals were isolated and genomic DNA of the entire cochlea was analyzed for donor contribution by Y-chromosome-specific PCR. All animals had normal thresholds in brainstem evoked response audiometry. The male-specific PCR product indicating the presence of male donor cells were detected in the cochleas of three of the four female animals investigated. In two animals, male donor cells were detected unilateral, in one animal bilateral. The results suggest that descendants of neural stem cells are detectable in the inner ear after injection into blastocysts and possess the ability to integrate into the developing inner ear without obvious loss in hearing function.

Non-Invasive Ultrasonic Diagnosing and Monitoring of Intracranial Pressure/Volume

DTIC Science & Technology

2001-10-01

these risks, intracranial pressure is usually monitored only in the severely head injured patients and only if there is clinical or CT or MRI ...proportion of patients for whom the computer tomography (CT) or magnetic resonance imaging ( MRI ) scan do not show the evidence of the raised pressure...thresholds and the Cushing phenomenon induced by upper brainstem ischemia. During ICH it was demonstrated that there is an increase of sympathetic

The c-FOS Protein Immunohistological Detection: A Useful Tool As a Marker of Central Pathways Involved in Specific Physiological Responses In Vivo and Ex Vivo

PubMed Central

Perrin-Terrin, Anne-Sophie; Jeton, Florine; Pichon, Aurelien; Frugière, Alain; Richalet, Jean-Paul; Bodineau, Laurence; Voituron, Nicolas

2016-01-01

Many studies seek to identify and map the brain regions involved in specific physiological regulations. The proto-oncogene c-fos, an immediate early gene, is expressed in neurons in response to various stimuli. The protein product can be readily detected with immunohistochemical techniques leading to the use of c-FOS detection to map groups of neurons that display changes in their activity. In this article, we focused on the identification of brainstem neuronal populations involved in the ventilatory adaptation to hypoxia or hypercapnia. Two approaches were described to identify involved neuronal populations in vivo in animals and ex vivo in deafferented brainstem preparations. In vivo, animals were exposed to hypercapnic or hypoxic gas mixtures. Ex vivo, deafferented preparations were superfused with hypoxic or hypercapnic artificial cerebrospinal fluid. In both cases, either control in vivo animals or ex vivo preparations were maintained under normoxic and normocapnic conditions. The comparison of these two approaches allows the determination of the origin of the neuronal activation i.e., peripheral and/or central. In vivo and ex vivo, brainstems were collected, fixed, and sliced into sections. Once sections were prepared, immunohistochemical detection of the c-FOS protein was made in order to identify the brainstem groups of cells activated by hypoxic or hypercapnic stimulations. Labeled cells were counted in brainstem respiratory structures. In comparison to the control condition, hypoxia or hypercapnia increased the number of c-FOS labeled cells in several specific brainstem sites that are thus constitutive of the neuronal pathways involved in the adaptation of the central respiratory drive. PMID:27167092

A voxel-based investigation for MRI-only radiotherapy of the brain using ultra short echo times

NASA Astrophysics Data System (ADS)

Edmund, Jens M.; Kjer, Hans M.; Van Leemput, Koen; Hansen, Rasmus H.; Andersen, Jon AL; Andreasen, Daniel

2014-12-01

Radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, so-called MRI-only RT, would remove the systematic registration error between MR and computed tomography (CT), and provide co-registered MRI for assessment of treatment response and adaptive RT. Electron densities, however, need to be assigned to the MRI images for dose calculation and patient setup based on digitally reconstructed radiographs (DRRs). Here, we investigate the geometric and dosimetric performance for a number of popular voxel-based methods to generate a so-called pseudo CT (pCT). Five patients receiving cranial irradiation, each containing a co-registered MRI and CT scan, were included. An ultra short echo time MRI sequence for bone visualization was used. Six methods were investigated for three popular types of voxel-based approaches; (1) threshold-based segmentation, (2) Bayesian segmentation and (3) statistical regression. Each approach contained two methods. Approach 1 used bulk density assignment of MRI voxels into air, soft tissue and bone based on logical masks and the transverse relaxation time T2 of the bone. Approach 2 used similar bulk density assignments with Bayesian statistics including or excluding additional spatial information. Approach 3 used a statistical regression correlating MRI voxels with their corresponding CT voxels. A similar photon and proton treatment plan was generated for a target positioned between the nasal cavity and the brainstem for all patients. The CT agreement with the pCT of each method was quantified and compared with the other methods geometrically and dosimetrically using both a number of reported metrics and introducing some novel metrics. The best geometrical agreement with CT was obtained with the statistical regression methods which performed significantly better than the threshold and Bayesian segmentation methods (excluding spatial information). All methods agreed significantly better with CT than a reference water MRI comparison. The mean dosimetric deviation for photons and protons compared to the CT was about 2% and highest in the gradient dose region of the brainstem. Both the threshold based method and the statistical regression methods showed the highest dosimetrical agreement. Generation of pCTs using statistical regression seems to be the most promising candidate for MRI-only RT of the brain. Further, the total amount of different tissues needs to be taken into account for dosimetric considerations regardless of their correct geometrical position.

Human handedness and asymmetry of the motor cortical silent period.

PubMed

Priori, A; Oliviero, A; Donati, E; Callea, L; Bertolasi, L; Rothwell, J C

1999-10-01

We performed transcranial magnetic stimulation of the motor cortex in 22 left-handed and 25 right-handed subjects during active contraction of a small hand muscle. Motor evoked potentials had the same latency, amplitude and threshold on both sides of the body, whilst the silent period duration was shorter in the dominant hand. Silent periods elicited by nerve and brainstem stimulation were the same in both hands. Since the latter part of the cortical silent period is due mainly to withdrawal of corticospinal input to spinal motoneurones, we speculate that the results are compatible with the suggestion that tonic contractions of the non-dominant hand are associated with a greater involvement of the corticospinal tract than those of the dominant hand. It also seems likely that there is an asymmetry in the excitability of cortical inhibitory mechanisms with those responsible for the cortical silent period being less excitable in the dominant motor cortex.

The Clinical Uses of Electrocochleography

PubMed Central

Gibson, William P.

2017-01-01

The clinical uses of electrocochleography are reviewed with some technical notes on the apparatus needed to get clear recordings under different conditions. Electrocochleography can be used to estimate auditory thresholds in difficult to test children and a golf club electrode is described. The same electrode can be used to obtain electrical auditory brainstem responses (EABR). Diagnostic testing in the clinic can be performed with a transtympanic needle electrode, and a suitable disposable monopolar electrode is described. The use of tone bursts rather than click stimuli gives a better means of diagnosis of the presence of endolymphatic hydrops. Electrocochleography can be used to monitor the cochlear function during surgery and a long coaxial cable, which can be sterilized, is needed to avoid electrical artifacts. Recently electrocochleography has been used to monitor cochlear implant insertion and to record residual hearing using an electrode on the cochlear implant array as the non-inverting (active) electrode. PMID:28634435

The Clinical Uses of Electrocochleography.

PubMed

Gibson, William P

2017-01-01

The clinical uses of electrocochleography are reviewed with some technical notes on the apparatus needed to get clear recordings under different conditions. Electrocochleography can be used to estimate auditory thresholds in difficult to test children and a golf club electrode is described. The same electrode can be used to obtain electrical auditory brainstem responses (EABR). Diagnostic testing in the clinic can be performed with a transtympanic needle electrode, and a suitable disposable monopolar electrode is described. The use of tone bursts rather than click stimuli gives a better means of diagnosis of the presence of endolymphatic hydrops. Electrocochleography can be used to monitor the cochlear function during surgery and a long coaxial cable, which can be sterilized, is needed to avoid electrical artifacts. Recently electrocochleography has been used to monitor cochlear implant insertion and to record residual hearing using an electrode on the cochlear implant array as the non-inverting (active) electrode.

Mechanical Damage of Tympanic Membrane in Relation to Impulse Pressure Waveform – A Study in Chinchillas

PubMed Central

Gan, Rong Z.; Nakmali, Don; Ji, Xiao D.; Leckness, Kegan; Yokell, Zachary

2016-01-01

Mechanical damage to middle ear components in blast exposure directly causes hearing loss, and the rupture of the tympanic membrane (TM) is the most frequent injury of the ear. However, it is unclear how the severity of injury graded by different patterns of TM rupture is related to the overpressure waveforms induced by blast waves. In the present study, the relationship between the TM rupture threshold and the impulse or overpressure waveform has been investigated in chinchillas. Two groups of animals were exposed to blast overpressure simulated in our lab under two conditions: open field and shielded with a stainless steel cup covering the animal head. Auditory brainstem response (ABR) and wideband tympanometry were measured before and after exposure to check the hearing threshold and middle ear function. Results show that waveforms recorded in the shielded case were different from those in the open field and the TM rupture threshold in the shielded case was lower than that in the open field (3.4±0.7 vs. 9.1±1.7 psi or 181±1.6 vs. 190±1.9 dB SPL). The impulse pressure energy spectra analysis of waveforms demonstrates that the shielded waveforms include greater energy at high frequencies than that of the open field waves. Finally, a 3D finite element (FE) model of the chinchilla ear was used to compute the distributions of stress in the TM and the TM displacement with impulse pressure waves. The FE model-derived change of stress in response to pressure loading in the shielded case was substantially faster than that in the open case. This finding provides the biomechanical mechanisms for blast induced TM damage in relation to overpressure waveforms. The TM rupture threshold difference between the open and shielded cases suggests that an acoustic role of helmets may exist, intensifying ear injury during blast exposure. PMID:26807796

Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

NASA Technical Reports Server (NTRS)

Hecox, K.; Squires, N.; Galambos, R.

1975-01-01

Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise burst duration (on-time) inter-burst interval (off-time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise-time but was unaffected by changes in fall-time. The amplitude of wave V was insensitive to changes in signal rise-and-fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It is concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

Changes in pitch height elicit both language universal and language dependent changes in neural representation of pitch in the brainstem and auditory cortex

PubMed Central

Krishnan, Ananthanarayan; Suresh, Chandan H.; Gandour, Jackson T.

2017-01-01

Language experience shapes encoding of pitch-relevant information at both brainstem and cortical levels of processing. Pitch height is a salient dimension that orders pitch from low to high. Herein we investigate the effects of language experience (Chinese, English) in the brainstem and cortex on i) neural responses to variations in pitch height, ii) presence of asymmetry in cortical pitch representation, and iii) patterns of relative changes in magnitude of pitch height between these two levels of brain structure. Stimuli were three nonspeech homologs of Mandarin Tone 2 varying in pitch height only. The frequency-following response (FFR) and the cortical pitch-specific response (CPR) were recorded concurrently. At the Fz-linked T7/T8 site, peak latency of Na, Pb, and Nb decreased with increasing pitch height for both groups. Peak-to-peak amplitude of Na–Pb and Pb–Nb increased with increasing pitch height across groups. A language-dependent effect was restricted to Na-Pb; the Chinese had larger amplitude than the English group. At temporal sites (T7/T8), the Chinese group had larger amplitude, as compared to English, across stimuli, but also limited to the Na-Pb component and right temporal site. In the brainstem, F0 magnitude decreased with increasing pitch height; Chinese had larger magnitude across stimuli. A comparison of CPR and FFR responses revealed distinct patterns of relative changes in magnitude common to both groups. CPR amplitude increased and FFR amplitude decreased with increasing pitch height. Experience-dependent effects on CPR components vary as a function of neural sensitivity to pitch height within a particular temporal window (Na–Pb). Differences between the auditory brainstem and cortex imply distinct neural mechanisms for pitch extraction at both levels of brain structure. PMID:28108254

Changes in pitch height elicit both language-universal and language-dependent changes in neural representation of pitch in the brainstem and auditory cortex.

PubMed

Krishnan, Ananthanarayan; Suresh, Chandan H; Gandour, Jackson T

2017-03-27

Language experience shapes encoding of pitch-relevant information at both brainstem and cortical levels of processing. Pitch height is a salient dimension that orders pitch from low to high. Herein we investigate the effects of language experience (Chinese, English) in the brainstem and cortex on (i) neural responses to variations in pitch height, (ii) presence of asymmetry in cortical pitch representation, and (iii) patterns of relative changes in magnitude of pitch height between these two levels of brain structure. Stimuli were three nonspeech homologs of Mandarin Tone 2 varying in pitch height only. The frequency-following response (FFR) and the cortical pitch-specific response (CPR) were recorded concurrently. At the Fz-linked T7/T8 site, peak latency of Na, Pb, and Nb decreased with increasing pitch height for both groups. Peak-to-peak amplitude of Na-Pb and Pb-Nb increased with increasing pitch height across groups. A language-dependent effect was restricted to Na-Pb; the Chinese had larger amplitude than the English group. At temporal sites (T7/T8), the Chinese group had larger amplitude, as compared to English, across stimuli, but also limited to the Na-Pb component and right temporal site. In the brainstem, F0 magnitude decreased with increasing pitch height; Chinese had larger magnitude across stimuli. A comparison of CPR and FFR responses revealed distinct patterns of relative changes in magnitude common to both groups. CPR amplitude increased and FFR amplitude decreased with increasing pitch height. Experience-dependent effects on CPR components vary as a function of neural sensitivity to pitch height within a particular temporal window (Na-Pb). Differences between the auditory brainstem and cortex imply distinct neural mechanisms for pitch extraction at both levels of brain structure. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Development of N-Methyl-D-Aspartate Receptor Subunits in Avian Auditory Brainstem

PubMed Central

TANG, YE-ZHONG; CARR, CATHERINE E.

2012-01-01

N-methyl-D-aspartate (NMDA) receptor subunit-specific probes were used to characterize developmental changes in the distribution of excitatory amino acid receptors in the chicken’s auditory brainstem nuclei. Although NR1 subunit expression does not change greatly during the development of the cochlear nuclei in the chicken (Tang and Carr [2004] Hear. Res 191:79 – 89), there are significant developmental changes in NR2 subunit expression. We used in situ hybridization against NR1, NR2A, NR2B, NR2C, and NR2D to compare NR1 and NR2 expression during development. All five NMDA subunits were expressed in the auditory brainstem before embryonic day (E) 10, when electrical activity and synaptic responses appear in the nucleus magnocellularis (NM) and the nucleus laminaris (NL). At this time, the dominant form of the receptor appeared to contain NR1 and NR2B. NR2A appeared to replace NR2B by E14, a time that coincides with synaptic refinement and evoked auditory responses. NR2C did not change greatly during auditory development, whereas NR2D increased from E10 and remained at fairly high levels into adulthood. Thus changes in NMDA NR2 receptor subunits may contribute to the development of auditory brainstem responses in the chick. PMID:17366608

Auditory- and visual-evoked potentials in Mexican infants are not affected by maternal supplementation with 400 mg/d docosahexaenoic acid in the second half of pregnancy.

PubMed

Stein, Aryeh D; Wang, Meng; Rivera, Juan A; Martorell, Reynaldo; Ramakrishnan, Usha

2012-08-01

The evidence relating prenatal supplementation with DHA to offspring neurological development is limited. We investigated the effect of prenatal DHA supplementation on infant brainstem auditory-evoked responses and visual- evoked potentials in a double-blind, randomized controlled trial in Cuernavaca, Mexico. Pregnant women were supplemented daily with 400 mg DHA or placebo from gestation wk 18-22 through delivery. DHA and placebo groups did not differ in maternal characteristics at randomization or infant characteristics at birth. Brainstem auditory-evoked responses were measured at 1 and 3 mo in 749 and 664 infants, respectively, and visual-evoked potentials were measured at 3 and 6 mo in 679 and 817 infants, respectively. Left-right brainstem auditory-evoked potentials were moderately correlated (range, 0.26-0.43; all P < 0.001) and left-right visual-evoked potentials were strongly correlated (range, 0.79-0.94; all P < 0.001) within any assessment. Correlations across visits were modest to moderate (range, 0.09-0.38; all P < 0.01). The offspring of DHA-supplemented women did not differ from those of control women with respect to any outcome measure (all comparisons P > 0.10). We conclude that DHA supplementation during pregnancy did not influence brainstem auditory-evoked responses at 1 and 3 mo or visual-evoked potentials at 3 and 6 mo.

TASK-2 Channels Contribute to pH Sensitivity of Retrotrapezoid Nucleus Chemoreceptor Neurons

PubMed Central

Wang, Sheng; Benamer, Najate; Zanella, Sébastien; Kumar, Natasha N.; Shi, Yingtang; Bévengut, Michelle; Penton, David; Guyenet, Patrice G.; Lesage, Florian

2013-01-01

Phox2b-expressing glutamatergic neurons of the retrotrapezoid nucleus (RTN) display properties expected of central respiratory chemoreceptors; they are directly activated by CO2/H+ via an unidentified pH-sensitive background K+ channel and, in turn, facilitate brainstem networks that control breathing. Here, we used a knock-out mouse model to examine whether TASK-2 (K2P5), an alkaline-activated background K+ channel, contributes to RTN neuronal pH sensitivity. We made patch-clamp recordings in brainstem slices from RTN neurons that were identified by expression of GFP (directed by the Phox2b promoter) or β-galactosidase (from the gene trap used for TASK-2 knock-out). Whereas nearly all RTN cells from control mice were pH sensitive (95%, n = 58 of 61), only 56% of GFP-expressing RTN neurons from TASK-2−/− mice (n = 49 of 88) could be classified as pH sensitive (>30% reduction in firing rate from pH 7.0 to pH 7.8); the remaining cells were pH insensitive (44%). Moreover, none of the recorded RTN neurons from TASK-2−/− mice selected based on β-galactosidase activity (a subpopulation of GFP-expressing neurons) were pH sensitive. The alkaline-activated background K+ currents were reduced in amplitude in RTN neurons from TASK-2−/− mice that retained some pH sensitivity but were absent from pH-insensitive cells. Finally, using a working heart–brainstem preparation, we found diminished inhibition of phrenic burst amplitude by alkalization in TASK-2−/− mice, with apneic threshold shifted to higher pH levels. In conclusion, alkaline-activated TASK-2 channels contribute to pH sensitivity in RTN neurons, with effects on respiration in situ that are particularly prominent near apneic threshold. PMID:24107938

Hearing status in adult individuals with lifetime, untreated isolated growth hormone deficiency.

PubMed

Prado-Barreto, Valéria M; Salvatori, Roberto; Santos Júnior, Ronaldo C; Brandão-Martins, Mariane B; Correa, Eric A; Garcez, Flávia B; Valença, Eugênia H O; Souza, Anita H O; Pereira, Rossana M C; Nunes, Marco A P; D'Avila, Jeferson S; Aguiar-Oliveira, Manuel H

2014-03-01

To evaluate the hearing status of growth hormone (GH)-naive adults with isolated GH deficiency (IGHD) belonging to an extended Brazilian kindred with a homozygous mutation in the GH-releasing hormone receptor gene. Cross-sectional. Divisions of Endocrinology and Otorhinolaryngology of the Federal University of Sergipe. Twenty-six individuals with IGHD (age, 47.6 ± 15.1 years; 13 women) and 25 controls (age, 46.3 ± 14.3 years; 15 women) were administered a questionnaire on hearing complaints and hearing health history. We performed pure-tone audiometry, logoaudiometry, electroacoustic immittance, and stapedial reflex. To assess outer hair cell function in the cochlea, we completed transient evoked otoacoustic emissions (TEOAEs). To assess the auditory nerve and auditory brainstem, we obtained auditory brainstem responses (ABRs). Misophonia and dizziness complaints were more frequent in those with IGHD than in controls (P = .011). Patients with IGHD had higher thresholds at 250 Hz (P = .005), 500 Hz (P = .006), 3 KHz (P = .008), 4 KHz (P = .038), 6 KHz (P = .008), and 8 KHz (P = .048) and mild high-tones hearing loss (P = .029). Stapedial reflex (P < .001) and TEOAEs (P = .025) were more frequent in controls. There were no differences in ABR latencies. Hearing loss in patients with IGHD occurred earlier than in controls (P < .001). Compared with controls of the same area, subjects with untreated, congenital lifetime IGHD report more misophonia and dizziness, have predominance of mild high-tones sensorineural hearing loss, and have an absence of stapedial reflex and TEOAEs.

Neonatal brainstem dysfunction risks infant social engagement

PubMed Central

Sopher, Koreen; Kurtzman, Lea; Galili, Giora; Feldman, Ruth; Kuint, Jacob

2013-01-01

The role of the brainstem in mediating social signaling in phylogenetic ancestral organisms has been demonstrated. Evidence for its involvement in social engagement in human infants may deepen the understanding of the evolutionary pathway of humans as social beings. In this longitudinal study, neonatal brainstem functioning was measured by auditory brainstem-evoked responses (ABRs) in 125 healthy neonates born prematurely before 35 weeks’ gestational age. At 4 months, infants were tested in a set of structured vignettes that required varying levels of social engagement and cardiac vagal tone was assessed. Data show that neonates with a disrupted I–V waveform, evident mostly by delayed wave V, exhibit shorter latencies to gaze averts in episodes involving direct face-to-face interactions but engage gaze as controls when interacting with masked agents or with agents whose faces are partly veiled by toys. Analysis of variance of infants’ social engagement with ABR, neonatal risk, maternal stress and cardiac vagal tone showed a main effect for ABR and an ABR by gestational age interaction. The integrity of brainstem transmission of sensory information during the final weeks of gestation may scaffold the development of social disengagement, thereby attesting to the brainstem's preserved evolutionary role in developing humans as social organisms prior to engaging in social encounters. PMID:22146141

Curcumin restores diabetes induced neurochemical changes in the brain stem of Wistar rats.

PubMed

Kumar, Peeyush T; George, Naijil; Antony, Sherin; Paulose, Cheramadathikudiyil Skaria

2013-02-28

Diabetes mellitus, when poorly controlled, leads to debilitating central nervous system (CNS) complications including cognitive deficits, somatosensory and motor dysfunction. The present study investigated curcumin's potential in modulating diabetes induced neurochemical changes in brainstem. Expression analysis of cholinergic, insulin receptor and GLUT-3 in the brainstem of streptozotocin (STZ) induced diabetic rats were studied. Radioreceptor binding assays, gene expression studies and immunohistochemical analysis were done in the brainstem of male Wistar rats. Our result showed that Bmax of total muscarinic and muscarinic M3 receptors were increased and muscarinic M1 receptor was decreased in diabetic rats compared to control. mRNA level of muscarinic M3, α7-nicotinic acetylcholine, insulin receptors, acetylcholine esterase, choline acetyltransferase and GLUT-3 significantly increased and M1 receptor decreased in the brainstem of diabetic rats. Curcumin and insulin treatment restored the alterations and maintained all parameters to near control. The results show that diabetes is associated with significant reduction in brainstem function coupled with altered cholinergic, insulin receptor and GLUT-3 gene expression. The present study indicates beneficial effect of curcumin in diabetic rats by regulating the cholinergic, insulin receptor and GLUT-3 in the brainstem similar to the responses obtained with insulin therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

Brainstem dysfunction protects against syncope in multiple sclerosis.

PubMed

Habek, Mario; Krbot Skorić, Magdalena; Crnošija, Luka; Adamec, Ivan

2015-10-15

The aim of this study was to investigate the correlation between autonomic dysfunction in multiple sclerosis (MS) and brainstem dysfunction evaluated with the vestibular evoked myogenic potentials (VEMP) score and conventional MRI. Forty-five patients with the diagnosis of clinically isolated syndrome (CIS) suggestive of MS were enrolled. VEMP, heart rate, and blood pressure responses to the Valsalva maneuver, heart rate response to deep breathing, and pain provoked head-up tilt table test, as well as brain and spinal cord MRI were performed. There was no difference in the VEMP score between patients with and without signs of sympathetic or parasympathetic dysfunction. However, patients with syncope had significantly lower VEMP score compared to patients without syncope (p<0.01). Patients with orthostatic hypotension (OH) showed a trend of higher VEMP score compared to patients without OH (p=0.06). There was no difference in the presence of lesions in the brainstem or cervical spinal cord between patients with or without any of the studied autonomic parameters. The model consisting of a VEMP score of ≤5 and normal MRI of the midbrain and cervical spinal cord has sensitivity and specificity of 83% for the possibility that the patient with MS can develop syncope. Pathophysiological mechanisms underlying functional and structural disorders of autonomic nervous system in MS differ significantly. While preserved brainstem function is needed for development of syncope, structural disorders like OH could be associated with brainstem dysfunction. Copyright © 2015 Elsevier B.V. All rights reserved.

Mature middle and inner ears express Chd7 and exhibit distinctive pathologies in a mouse model of CHARGE syndrome.

PubMed

Hurd, Elizabeth A; Adams, Meredith E; Layman, Wanda S; Swiderski, Donald L; Beyer, Lisa A; Halsey, Karin E; Benson, Jennifer M; Gong, Tzy-Wen; Dolan, David F; Raphael, Yehoash; Martin, Donna M

2011-12-01

Heterozygous mutations in the gene encoding chromodomain-DNA-binding-protein 7 (CHD7) cause CHARGE syndrome, a multiple anomaly condition which includes vestibular dysfunction and hearing loss. Mice with heterozygous Chd7 mutations exhibit semicircular canal dysgenesis and abnormal inner ear neurogenesis, and are an excellent model of CHARGE syndrome. Here we characterized Chd7 expression in mature middle and inner ears, analyzed morphological features of mutant ears and tested whether Chd7 mutant mice have altered responses to noise exposure and correlated those responses to inner and middle ear structure. We found that Chd7 is highly expressed in mature inner and outer hair cells, spiral ganglion neurons, vestibular sensory epithelia and middle ear ossicles. There were no obvious defects in individual hair cell morphology by prestin immunostaining or scanning electron microscopy, and cochlear innervation appeared normal in Chd7(Gt)(/+) mice. Hearing thresholds by auditory brainstem response (ABR) testing were elevated at 4 and 16 kHz in Chd7(Gt)(/+) mice, and there were reduced distortion product otoacoustic emissions (DPOAE). Exposure of Chd7(Gt)(/+) mice to broadband noise resulted in variable degrees of hair cell loss which inversely correlated with severity of stapedial defects. The degrees of hair cell loss and threshold shifts after noise exposure were more severe in wild type mice than in mutants. Together, these data indicate that Chd7(Gt)(/+) mice have combined conductive and sensorineural hearing loss, correlating with changes in both middle and inner ears. Copyright © 2011 Elsevier B.V. All rights reserved.

Mature middle and inner ears express Chd7 and exhibit distinctive pathologies in a mouse model of CHARGE syndrome

PubMed Central

Hurd, Elizabeth A.; Adams, Meredith E.; Layman, Wanda S.; Swiderski, Donald L.; Beyer, Lisa A.; Halsey, Karin E.; Benson, Jennifer M.; Gong, Tzy-Wen; Dolan, David F.; Raphael, Yehoash; Martin, Donna M.

2011-01-01

Heterozygous mutations in the gene encoding chromodomain-DNA-binding-protein 7 (CHD7) cause CHARGE syndrome, a multiple anomaly condition which includes vestibular dysfunction and hearing loss. Mice with heterozygous Chd7 mutations exhibit semicircular canal dysgenesis and abnormal inner ear neurogenesis, and are an excellent model of CHARGE syndrome. Here we characterized Chd7 expression in mature middle and inner ears, analyzed morphological features of mutant ears and tested whether Chd7 mutant mice have altered responses to noise exposure and correlated those responses to inner and middle ear structure. We found that Chd7 is highly expressed in mature inner and outer hair cells, spiral ganglion neurons, vestibular sensory epithelia and middle ear ossicles. There were no obvious defects in individual hair cell morphology by Prestin immunostaining or scanning electron microscopy, and cochlear innervation appeared normal in Chd7Gt/+ mice. Hearing thresholds by auditory brainstem response (ABR) testing were elevated at 4 and 16 kHz in Chd7Gt/+ mice, and there were reduced distortion product otoacoustic emissions (DPOAE). Exposure of Chd7Gt/+ mice to broadband noise resulted in variable degrees of hair cell loss which inversely correlated with severity of stapedial defects. The degrees of hair cell loss and threshold shifts after noise exposure were more severe in wild type mice than in mutants. Together, these data indicate that Chd7Gt/+ mice have combined conductive and sensorineural hearing loss, correlating with changes in both middle and inner ears. PMID:21875659

Modeling the impact of impulsive stimuli on sleep-wake dynamics

NASA Astrophysics Data System (ADS)

Fulcher, B. D.; Phillips, A. J. K.; Robinson, P. A.

2008-11-01

A neuronal population model of the sleep-wake switch is extended to incorporate impulsive external stimuli. The model includes the mutual inhibition of the sleep-active neurons in the hypothalamic ventrolateral preoptic area (VLPO) and the wake-active monoaminergic brainstem populations (MA), as well as circadian and homeostatic drives. Arbitrary stimuli are described in terms of their relative effects on the VLPO and MA nuclei and represent perturbations on the normal sleep-wake dynamics. By separating the model’s intrinsic time scales, an analytic characterization of the dynamics in a reduced model space is developed. Using this representation, the model’s response to stimuli is studied, including the latency to return to wake or sleep, or to elicit a transition between the two states. Since sensory stimuli are known to excite the MA, we correspondingly investigate the model’s response to auditory tones during sleep, as in clinical sleep fragmentation studies. The arousal threshold is found to vary approximately linearly with the model’s total sleep drive, which includes circadian and homeostatic components. This relationship is used to reproduce the clinically observed variation of the arousal threshold across the night, which rises to a maximum near the middle of the night and decreases thereafter. In a further application of the model, time-of-night arousal threshold and body temperature variations in an experimental sleep fragmentation study are replicated. It is proposed that the shift of the extrema of these curves to a greater magnitude later in the night is due to the homeostatic impact of the frequent nocturnal disturbances. By modeling the underlying neuronal interactions, the methods presented here allow the prediction of arousal state responses to external stimuli. This methodology is fundamentally different to previous approaches that model the clinical data within a phenomenological framework. As a result, a broader understanding of how impulsive external stimuli modulate arousal is gained.

Auditory- and Vestibular-Evoked Potentials Correlate with Motor and Non-Motor Features of Parkinson’s Disease

PubMed Central

Shalash, Ali Soliman; Hassan, Dalia Mohamed; Elrassas, Hanan Hani; Salama, Mohamed Mosaad; Méndez-Hernández, Edna; Salas-Pacheco, José M.; Arias-Carrión, Oscar

2017-01-01

Degeneration of several brainstem nuclei has been long related to motor and non-motor symptoms (NMSs) of Parkinson’s disease (PD). Nevertheless, due to technical issues, there are only a few studies that correlate that association. Brainstem auditory-evoked potential (BAEP) and vestibular-evoked myogenic potential (VEMP) responses represent a valuable tool for brainstem assessment. Here, we investigated the abnormalities of BAEPs, ocular VEMPs (oVEMPs), and cervical VEMPs (cVEMPs) in patients with PD and its correlation to the motor and NMSs. Fifteen patients diagnosed as idiopathic PD were evaluated by Unified Parkinson’s Disease Rating Scale and its subscores, Hoehn and Yahr scale, Schwab and England scale, and Non-Motor Symptoms Scale. PD patients underwent pure-tone, speech audiometry, tympanometry, BAEP, oVEMPs, and cVEMPs, and compared to 15 age-matched control subjects. PD subjects showed abnormal BAEP wave morphology, prolonged absolute latencies of wave V and I–V interpeak latencies. Absent responses were the marked abnormality seen in oVEMP. Prolonged latencies with reduced amplitudes were seen in cVEMP responses. Rigidity and bradykinesia were correlated to the BAEP and cVEMP responses contralateral to the clinically more affected side. Contralateral and ipsilateral cVEMPs were significantly correlated to sleep (p = 0.03 and 0.001), perception (p = 0.03), memory/cognition (p = 0.025), and urinary scores (p = 0.03). The oVEMP responses showed significant correlations to cardiovascular (p = 0.01) and sexual dysfunctions (p = 0.013). PD is associated with BAEP and VEMP abnormalities that are correlated to the motor and some non-motor clinical characteristics. These abnormalities could be considered as potential electrophysiological biomarkers for brainstem dysfunction and its associated motor and non-motor features. PMID:28289399

Cortical influences on brainstem circuitry responsible for conditioned pain modulation in humans.

PubMed

Youssef, Andrew M; Macefield, Vaughan G; Henderson, Luke A

2016-07-01

Conditioned pain modulation (CPM) is a powerful endogenous analgesic mechanism which can completely inhibit incoming nociceptor signals at the primary synapse. The circuitry responsible for CPM lies within the brainstem and involves the subnucleus reticularis dorsalis (SRD). While the brainstem is critical for CPM, the cortex can significantly modulate its expression, likely via the brainstem circuitry critical for CPM. Since higher cortical regions such as the anterior, mid-cingulate, and dorsolateral prefrontal cortices are activated by noxious stimuli and show reduced activations during other analgesic responses, we hypothesized that these regions would display reduced responses during CPM analgesia. Furthermore, we hypothesized that functional connectivity strength between these cortical regions and the SRD would be stronger in those that express CPM analgesia compared with those that do not. We used functional magnetic resonance imaging to determine sites recruited during CPM expression and their influence on the SRD. A lack of CPM analgesia was associated with greater signal intensity increases during each test stimulus in the presence of the conditioning stimulus compared to test stimuli alone in the mid-cingulate and dorsolateral prefrontal cortices and increased functional connectivity with the SRD. In contrast, those subjects exhibiting CPM analgesia showed no change in the magnitude of signal intensity increases in these cortical regions or strength of functional connectivity with the SRD. These data suggest that during multiple or widespread painful stimuli, engagement of the prefrontal and cingulate cortices prevents the generation of CPM analgesia, raising the possibility altered responsiveness in these cortical regions underlie the reduced CPM observed in individuals with chronic pain. Hum Brain Mapp 37:2630-2644, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Solid lipid nanoparticles loaded with edaravone for inner ear protection after noise exposure.

PubMed

Gao, Gang; Liu, Ya; Zhou, Chang-Hua; Jiang, Ping; Sun, Jian-Jun

2015-01-20

Antioxidants and the duration of treatment after noise exposure on hearing recovery are important. We investigated the protective effects of an antioxidant substance, edaravone, and its slow-release dosage form, edaravone solid lipid nanoparticles (SLNs), in steady noise-exposed guinea pigs. SLNs loaded with edaravone were produced by an ultrasound technique. Edaravone solution or edaravone SLNs were administered by intratympanic or intravenous injection after the 1 st day of noise exposure. Guinea pigs were exposed to 110 dB sound pressure level (SPL) noise, centered at 0.25-4.0 kHz, for 4 days at 2 h/d. After noise exposure, the guinea pigs underwent auditory brainstem response (ABR) threshold measurements, reactive oxygen species (ROS) were detected in their cochleas with electron spin resonance (ESR), and outer hair cells (OHCs) were counted with silvernitrate (AgNO 3 ) staining at 1, 4, and 6 days. The ultrasound technique was able to prepare adequate edaravone SLNs with a mean particle size of 93.6 nm and entrapment efficiency of 76.7%. Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea. Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group. Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL).

Solid Lipid Nanoparticles Loaded with Edaravone for Inner Ear Protection After Noise Exposure

PubMed Central

Gao, Gang; Liu, Ya; Zhou, Chang-Hua; Jiang, Ping; Sun, Jian-Jun

2015-01-01

Background: Antioxidants and the duration of treatment after noise exposure on hearing recovery are important. We investigated the protective effects of an antioxidant substance, edaravone, and its slow-release dosage form, edaravone solid lipid nanoparticles (SLNs), in steady noise-exposed guinea pigs. Methods: SLNs loaded with edaravone were produced by an ultrasound technique. Edaravone solution or edaravone SLNs were administered by intratympanic or intravenous injection after the 1st day of noise exposure. Guinea pigs were exposed to 110 dB sound pressure level (SPL) noise, centered at 0.25–4.0 kHz, for 4 days at 2 h/d. After noise exposure, the guinea pigs underwent auditory brainstem response (ABR) threshold measurements, reactive oxygen species (ROS) were detected in their cochleas with electron spin resonance (ESR), and outer hair cells (OHCs) were counted with silvernitrate (AgNO3) staining at 1, 4, and 6 days. Results: The ultrasound technique was able to prepare adequate edaravone SLNs with a mean particle size of 93.6 nm and entrapment efficiency of 76.7%. Acoustic stress-induced ROS formation and edaravone exerted a protective effect on the cochlea. Comparisons of hearing thresholds and ROS changes in different animal groups showed that the threshold shift and ROS generation were significantly lower in treated animals than in those without treatment, especially in the edaravone SLN intratympanic injection group. Conclusions: Edaravone SLNs show noticeable slow-release effects and have certain protective effects against noise-induced hearing loss (NIHL). PMID:25591563

In-Air Evoked Potential Audiometry of Grey Seals (Halichoerus grypus) from the North and Baltic Seas

PubMed Central

Ruser, Andreas; Dähne, Michael; Sundermeyer, Janne; Lucke, Klaus; Houser, Dorian S.; Finneran, James J.; Driver, Jörg; Pawliczka, Iwona; Rosenberger, Tanja; Siebert, Ursula

2014-01-01

In-air anthropogenic sound has the potential to affect grey seal (Halichoerus grypus) behaviour and interfere with acoustic communication. In this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. Using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (ABR) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. Thresholds were measured at 10 frequencies between 1–20 kHz. Measurements were made using subcutaneous electrodes on wild seals from the Baltic and North Seas. Thresholds were determined by both visual and statistical approaches (single point F-test) and good agreement was obtained between the results using both methods. The mean auditory thresholds were ≤40 dB re 20 µPa peak equivalent sound pressure level (peSPL) between 4–20 kHz and showed similar patterns to in-air behavioural hearing tests of other phocid seals between 3 and 20 kHz. Below 3 kHz, a steep reduction in hearing sensitivity was observed, which differed from the rate of decline in sensitivity obtained in behavioural studies on other phocids. Differences in the rate of decline may reflect influence of the ear inserts on the ability to reliably transmit lower frequencies or interference from the structure of the distal end of the ear canal. PMID:24632891

Neuronal erythropoietin overexpression is protective against kanamycin-induced hearing loss in mice.

PubMed

Bächinger, David; Horvath, Lukas; Eckhard, Andreas; Goosmann, Madeline M; Honegger, Tim; Gassmann, Max; Vogel, Johannes; Naldi, Arianne Monge

2018-07-01

Aminoglycosides have detrimental effects on the hair cells of the inner ear, yet these agents indisputably are one of the cornerstones in antibiotic therapy. Hence, there is a demand for strategies to prevent aminoglycoside-induced ototoxicity, which are not available today. In vitro data suggests that the pleiotropic growth factor erythropoietin (EPO) is neuroprotective against aminoglycoside-induced hair cell loss. Here, we use a mouse model with EPO-overexpression in neuronal tissue to evaluate whether EPO could also in vivo protect from aminoglycoside-induced hearing loss. Auditory brainstem response (ABR) thresholds were measured in 12-weeks-old mice before and after treatment with kanamycin for 15 days, which resulted in both C57BL/6 and EPO-transgenic animals in a high-frequency hearing loss. However, ABR threshold shifts in EPO-transgenic mice were significantly lower than in C57BL/6 mice (mean difference in ABR threshold shift 13.6 dB at 32 kHz, 95% CI 3.8-23.4 dB, p = 0.003). Correspondingly, quantification of hair cells and spiral ganglion neurons by immunofluorescence revealed that EPO-transgenic mice had a significantly lower hair cell and spiral ganglion neuron loss than C57BL/6 mice. In conclusion, neuronal overexpression of EPO is protective against aminoglycoside-induce hearing loss, which is in accordance with its known neuroprotective effects in other organs, such as the eye or the brain. Copyright © 2018 Elsevier B.V. All rights reserved.

Convergent input from brainstem coincidence detectors onto delay-sensitive neurons in the inferior colliculus.

PubMed

McAlpine, D; Jiang, D; Shackleton, T M; Palmer, A R

1998-08-01

Responses of low-frequency neurons in the inferior colliculus (IC) of anesthetized guinea pigs were studied with binaural beats to assess their mean best interaural phase (BP) to a range of stimulating frequencies. Phase plots (stimulating frequency vs BP) were produced, from which measures of characteristic delay (CD) and characteristic phase (CP) for each neuron were obtained. The CD provides an estimate of the difference in travel time from each ear to coincidence-detector neurons in the brainstem. The CP indicates the mechanism underpinning the coincidence detector responses. A linear phase plot indicates a single, constant delay between the coincidence-detector inputs from the two ears. In more than half (54 of 90) of the neurons, the phase plot was not linear. We hypothesized that neurons with nonlinear phase plots received convergent input from brainstem coincidence detectors with different CDs. Presentation of a second tone with a fixed, unfavorable delay suppressed the response of one input, linearizing the phase plot and revealing other inputs to be relatively simple coincidence detectors. For some neurons with highly complex phase plots, the suppressor tone altered BP values, but did not resolve the nature of the inputs. For neurons with linear phase plots, the suppressor tone either completely abolished their responses or reduced their discharge rate with no change in BP. By selectively suppressing inputs with a second tone, we are able to reveal the nature of underlying binaural inputs to IC neurons, confirming the hypothesis that the complex phase plots of many IC neurons are a result of convergence from simple brainstem coincidence detectors.

Evaluation of tinnitus patients by audiometric configuration.

PubMed

Kim, Su Il; Kim, Myung Gu; Kim, Sung Su; Byun, Jae Yong; Park, Moon Suh; Yeo, Seung Geun

2016-01-01

Although tinnitus patients have different audiometric configuration, we evaluated them using the same approach. Thus we analyzed the clinical features of patients with subjective tinnitus classified according to audiometric configuration. The study cohort consisted of 123 patients with subjective tinnitus who visited the tinnitus clinic from April 2013 to April 2014. Patients with a previous history of otologic disease or migrainous vertigo were excluded. Factors evaluated included pure tone audiometry, tinnitogram, auditory brainstem response (ABR), distortion product otoacoustic emissions (DPOAEs) and transient evoked otoacoustic emissions (TEOAEs). Tinnitus patients could be divided into three groups: Flat, high frequency gently sloping (HFGS) and high frequency steeply sloping (HFSS). HFGS showed female predominance and HFSS male predominance (p<0.05 each). THI score was higher in the HFGS than in the other groups (p<0.05). Tinnitus pitch and occupations varied, but showed specific tendencies in each group. On ABR, the HFSS group showed significant prolongation of wave I, III, and V latencies (p<0.05 each). On DPOAEs, the HFSS group showed significantly lower response rates at 3, 4, and 6 kHz (p<0.05 each). TEOAE normal rates were significantly higher in the Flat than in the HFGS and HFSS groups (p<0.05). Average pure tone thresholds were similar, but threshold values at high frequencies, ABR, DPOAEs, and TEOAEs differed among the groups. Therefore, different access to tinnitus patients could be required according to audiometric shape. Copyright © 2016 Elsevier Inc. All rights reserved.

Noise-induced cochlear synaptopathy in rhesus monkeys (Macaca mulatta).

PubMed

Valero, M D; Burton, J A; Hauser, S N; Hackett, T A; Ramachandran, R; Liberman, M C

2017-09-01

Cochlear synaptopathy can result from various insults, including acoustic trauma, aging, ototoxicity, or chronic conductive hearing loss. For example, moderate noise exposure in mice can destroy up to ∼50% of synapses between auditory nerve fibers (ANFs) and inner hair cells (IHCs) without affecting outer hair cells (OHCs) or thresholds, because the synaptopathy occurs first in high-threshold ANFs. However, the fiber loss likely impairs temporal processing and hearing-in-noise, a classic complaint of those with sensorineural hearing loss. Non-human primates appear to be less vulnerable to noise-induced hair-cell loss than rodents, but their susceptibility to synaptopathy has not been studied. Because establishing a non-human primate model may be important in the development of diagnostics and therapeutics, we examined cochlear innervation and the damaging effects of acoustic overexposure in young adult rhesus macaques. Anesthetized animals were exposed bilaterally to narrow-band noise centered at 2 kHz at various sound-pressure levels for 4 h. Cochlear function was assayed for up to 8 weeks following exposure via auditory brainstem responses (ABRs) and otoacoustic emissions (OAEs). A moderate loss of synaptic connections (mean of 12-27% in the basal half of the cochlea) followed temporary threshold shifts (TTS), despite minimal hair-cell loss. A dramatic loss of synapses (mean of 50-75% in the basal half of the cochlea) was seen on IHCs surviving noise exposures that produced permanent threshold shifts (PTS) and widespread hair-cell loss. Higher noise levels were required to produce PTS in macaques compared to rodents, suggesting that primates are less vulnerable to hair-cell loss. However, the phenomenon of noise-induced cochlear synaptopathy in primates is similar to that seen in rodents. Copyright © 2017 Elsevier B.V. All rights reserved.

Central nervous versus total body thermosensitivity of the duck

NASA Astrophysics Data System (ADS)

Simon, E.; Martin, R.; Simon-Oppermann, Ch.

1981-09-01

Ducks were chronically implanted with thermodes in the POAH region, the lower brainstem or the vertebral canal. At thermoneutral conditions, lowering the temperature of the spinal cord (Tvc) or the lower brainstem (Tmb) stimulated metabolic heat production (M) with a subsequent rise of core temperature (Tc). Lowering the temperature of the POAH region (Thy) induced a fall of Tc due to paradoxical activation of heat defence and, thus, induced slight to moderate general hypothermia depending on the cooling intensity. When Thy was normalized, the hypothermia temporarily stimulated metabolic heat production until Tc was normalized. Cold sensitivity of the entire body, as revealed by the metabolic response to the hypothermia induced by preceding POAH cooling, and cold sensitivity of the spinal cord and the lower brainstem, as revealed by the metabolic response to local cooling, were quantified by calculating the quotient δM/δT from the maximum metabolic response and the experimentally induced drop of Tc, Tmb and Tvc. With lower brainstem cooling δM/δTmbdid not exceed -0.4 W/(kg · ‡C). With spinal cord cooling, δM/δTvc did not exceed -0.6 W/(kg · ‡C). The mean value of δM/δTc after hypothermia induced by POAH cooling was -4.02 W/(kg · ‡C). The results indicate that the cold sensitivity residing in the CNS of ducks represents only a small fraction of the entire cold sensitivity of the body.

Auditory- and Visual-Evoked Potentials in Mexican Infants Are Not Affected by Maternal Supplementation with 400 mg/d Docosahexaenoic Acid in the Second Half of Pregnancy1234

PubMed Central

Stein, Aryeh D.; Wang, Meng; Rivera, Juan A.; Martorell, Reynaldo; Ramakrishnan, Usha

2012-01-01

The evidence relating prenatal supplementation with DHA to offspring neurological development is limited. We investigated the effect of prenatal DHA supplementation on infant brainstem auditory-evoked responses and visual- evoked potentials in a double-blind, randomized controlled trial in Cuernavaca, Mexico. Pregnant women were supplemented daily with 400 mg DHA or placebo from gestation wk 18–22 through delivery. DHA and placebo groups did not differ in maternal characteristics at randomization or infant characteristics at birth. Brainstem auditory-evoked responses were measured at 1 and 3 mo in 749 and 664 infants, respectively, and visual-evoked potentials were measured at 3 and 6 mo in 679 and 817 infants, respectively. Left-right brainstem auditory-evoked potentials were moderately correlated (range, 0.26–0.43; all P < 0.001) and left-right visual-evoked potentials were strongly correlated (range, 0.79–0.94; all P < 0.001) within any assessment. Correlations across visits were modest to moderate (range, 0.09–0.38; all P < 0.01). The offspring of DHA-supplemented women did not differ from those of control women with respect to any outcome measure (all comparisons P > 0.10). We conclude that DHA supplementation during pregnancy did not influence brainstem auditory-evoked responses at 1 and 3 mo or visual-evoked potentials at 3 and 6 mo. PMID:22739364

Impact of monaural frequency compression on binaural fusion at the brainstem level.

PubMed

Klauke, Isabelle; Kohl, Manuel C; Hannemann, Ronny; Kornagel, Ulrich; Strauss, Daniel J; Corona-Strauss, Farah I

2015-08-01

A classical objective measure for binaural fusion at the brainstem level is the so-called β-wave of the binaural interaction component (BIC) in the auditory brainstem response (ABR). However, in some cases it appeared that a reliable detection of this component still remains a challenge. In this study, we investigate the wavelet phase synchronization stability (WPSS) of ABR data for the analysis of binaural fusion and compare it to the BIC. In particular, we examine the impact of monaural nonlinear frequency compression on binaural fusion. As the auditory system is tonotopically organized, an interaural frequency mismatch caused by monaural frequency compression could negatively effect binaural fusion. In this study, only few subjects showed a detectable β-wave and in most cases only for low ITDs. However, we present a novel objective measure for binaural fusion that outperforms the current state-of-the-art technique (BIC): the WPSS analysis showed a significant difference between the phase stability of the sum of the monaurally evoked responses and the phase stability of the binaurally evoked ABR. This difference could be an indicator for binaural fusion in the brainstem. Furthermore, we observed that monaural frequency compression could indeed effect binaural fusion, as the WPSS results for this condition vary strongly from the results obtained without frequency compression.

Cerebral and brainstem electrophysiologic activity during euthanasia with pentobarbital sodium in horses.

PubMed

Aleman, M; Williams, D C; Guedes, A; Madigan, J E

2015-01-01

An overdose of pentobarbital sodium administered i.v. is the most commonly used method of euthanasia in veterinary medicine. Determining death after the infusion relies on the observation of physical variables. However, it is unknown when cortical electrical activity and brainstem function are lost in a sequence of events before death. To examine changes in the electrical activity of the cerebral cortex and brainstem during an overdose of pentobarbital sodium solution for euthanasia. Our testing hypothesis is that isoelectric pattern of the brain in support of brain death occurs before absence of electrocardiogram (ECG) activity. Fifteen horses requiring euthanasia. Prospective observational study. Horses with neurologic, orthopedic, and cardiac illnesses were selected and instrumented for recording of electroencephalogram, electrooculogram, brainstem auditory evoked response (BAER), and ECG. Physical and neurologic (brainstem reflexes) variables were monitored. Loss of cortical electrical activity occurred during or within 52 seconds after the infusion of euthanasia solution. Cessation of brainstem function as evidenced by a lack of brainstem reflexes and disappearance of the BAER happened subsequently. Despite undetectable heart sounds, palpable arterial pulse, and mean arterial pressure, recordable ECG was the last variable to be lost after the infusion (5.5-16 minutes after end of the infusion). Overdose of pentobarbital sodium solution administered i.v. is an effective, fast, and humane method of euthanasia. Brain death occurs within 73-261 seconds of the infusion. Although absence of ECG activity takes longer to occur, brain death has already occurred. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Application of a TNF-alpha-inhibitor into the scala tympany after cochlear electrode insertion trauma in guinea pigs: preliminary audiologic results.

PubMed

Ihler, Friedrich; Pelz, Sabrina; Coors, Melanie; Matthias, Christoph; Canis, Martin

2014-11-01

Cochlear implantation trauma causes both macroscopic and inflammatory trauma. The aim of the present study was to evaluate the effectiveness of the TNF-alpha inhibitor etanercept applied after cochlear implantation trauma on the preservation of acoustic hearing. Guinea pigs were randomly assigned to three groups receiving cochlear implantation trauma by cochleostomy. In one group, the site was sealed by bone cement with no further treatment. A second group was additionally implanted with an osmotic minipump delivering artificial perilymph into the scala tympani for seven days. In the third group, etanercept 1 mg/ml was added to artificial perilymph. Hearing was assessed by auditory brainstem responses at 2, 4, 6, and 8 kHz prior to and after surgery and on days 3, 5, 7, 14, 28. Fifteen healthy guinea pigs. The trauma led to threshold shifts from 50.3 dB ± 16.3 dB to 68.0 dB ± 19.3 dB. Hearing thresholds were significantly lower in etanercept-treated animals compared to controls on day 28 at 8 kHz and from day 3 onwards at 4 and 2 kHz (p < 0.01; two-way RM ANOVA / Bonferroni t-test). The application of etanercept led to preservation of acoustic hearing after cochlear implantation trauma.

Comparison of characteristics observed in tinnitus patients with unilateral vs bilateral symptoms, with both normal hearing threshold and distortion-product otoacoustic emissions.

PubMed

Zagólski, Olaf; Stręk, Paweł

2017-02-01

Tinnitus characteristics in normal-hearing patients differ between the groups with unilateral and bilateral complaints. The study was to determine the differences between tinnitus characteristics observed in patients with unilateral vs bilateral symptoms and normal hearing threshold, as well as normal results of distortion-product otoacoustic emissions (DPOAEs). The patients answered questions concerning tinnitus duration, laterality, character, accompanying symptoms, and circumstances of onset. The results of tympanometry, auditory brainstem responses, tinnitus likeness spectrum, minimum masking level (MML), and uncomfortable loudness level were evaluated. Records of 380 tinnitus sufferers were examined. Patients with abnormal audiograms and/or DPOAEs were excluded. The remaining 66 participants were divided into groups with unilateral and bilateral tinnitus. Unilateral tinnitus in normal-hearing patients was diagnosed twice more frequently than bilateral. Tinnitus pitch was higher in the group with bilateral tinnitus (p < .001). MML was lower in unilateral tinnitus (p < .05). Mean age of patients was higher in the unilateral tinnitus group (p < .05). Mean tinnitus duration was longer (p < .05) and hypersensitivity to sound was more frequent (p < .05) in the bilateral tinnitus group. Repeated exposure to excessive noise was the most frequent cause in the bilateral tinnitus group.

Keeping returns optimal: gain control exerted through sensitivity adjustments in the harbour porpoise auditory system

PubMed Central

Linnenschmidt, Meike; Beedholm, Kristian; Wahlberg, Magnus; Højer-Kristensen, Jakob; Nachtigall, Paul E.

2012-01-01

Animals that use echolocation (biosonar) listen to acoustic signals with a large range of intensities, because echo levels vary with the fourth power of the animal's distance to the target. In man-made sonar, engineers apply automatic gain control to stabilize the echo energy levels, thereby rendering them independent of distance to the target. Both toothed whales and bats vary the level of their echolocation clicks to compensate for the distance-related energy loss. By monitoring the auditory brainstem response (ABR) during a psychophysical task, we found that a harbour porpoise (Phocoena phocoena), in addition to adjusting the sound level of the outgoing signals up to 5.4 dB, also reduces its ABR threshold by 6 dB when the target distance doubles. This self-induced threshold shift increases the dynamic range of the biosonar system and compensates for half of the variation of energy that is caused by changes in the distance to the target. In combination with an increased source level as a function of target range, this helps the porpoise to maintain a stable echo-evoked ABR amplitude irrespective of target range, and is therefore probably an important tool enabling porpoises to efficiently analyse and classify received echoes. PMID:22279169

Involvement of p53 and Bcl-2 in sensory cell degeneration in aging rat cochleae.

PubMed

Xu, Yang; Yang, Wei Ping; Hu, Bo Hua; Yang, Shiming; Henderson, Donald

2017-06-01

p53 and Bcl-2 (B-cell lymphoma 2) are involved in the process of sensory cell degeneration in aging cochleae. To determine molecular players in age-related hair cell degeneration, this study examined the changes in p53 and Bcl-2 expression at different stages of apoptotic and necrotic death of hair cells in aging rat cochleae. Young (3-4 months) and aging (23-24 months) Fisher 344/NHsd rats were used. The thresholds of the auditory brainstem response (ABR) were measured to determine the auditory function. Immunolabeling was performed to determine the expression of p53 and Bcl-2 proteins in the sensory epithelium. Propidium iodide staining was performed to determine the morphologic changes in hair cell nuclei. Aging rats exhibited a significant elevation in ABR thresholds at all tested frequencies (p < 0.001). The p53 and Bcl-2 immunoreactivity was increased in aging hair cells showing the early signs of apoptotic changes in their nuclei. The Bcl-2 expression increase was also observed in hair cells displaying early signs of necrosis. As the hair cell degenerative process advanced, p53 and Bcl-2 immunoreactivity became reduced or absent. In the areas where no detectable nuclear staining was present, p53 and Bcl-2 immunoreactivity was absent.

Diffusion tensor imaging demonstrates brainstem and cerebellar abnormalities in congenital central hypoventilation syndrome.

PubMed

Kumar, Rajesh; Macey, Paul M; Woo, Mary A; Alger, Jeffry R; Harper, Ronald M

2008-09-01

Congenital central hypoventilation syndrome (CCHS) patients show reduced breathing drive during sleep, decreased hypoxic and hypercapnic ventilatory responses, and autonomic and affective deficits, suggesting both brainstem and forebrain injuries. Forebrain damage was previously described in CCHS, but methodological limitations precluded detection of brainstem injury, a concern because genetic mutations in CCHS target brainstem autonomic nuclei. To assess brainstem and cerebellar areas, we used diffusion tensor imaging-based measures, namely axial diffusivity, reflecting water diffusion parallel to fibers, and sensitive to axonal injury, and radial diffusivity, measuring diffusion perpendicular to fibers, and indicative of myelin injury. Diffusion tensor imaging was performed in 12 CCHS and 26 controls, and axial and radial diffusivity maps were compared between groups using analysis of covariance (covariates; age and gender). Increased axial diffusivity in CCHS appeared within the lateral medulla and clusters with injury extended from the dorsal midbrain through the periaqueductal gray, raphé, and superior cerebellar decussation, ventrally to the basal-pons. Cerebellar cortex and deep nuclei, and the superior and inferior cerebellar peduncles showed increased radial diffusivity. Midbrain, pontine, and lateral medullary structures, and the cerebellum and its fiber systems are injured in CCHS, likely contributing to the characteristics found in the syndrome.

Effect of absorbable gelatin sponge in the middle ear: in vitro and in vivo animal model.

PubMed

Goncalves, Stefania; Chiossone-Kerdel, Juan Armando; Bianco, Andrea S; Ercolino, Jose M; Hernandez-Rojas, Jorge

2015-01-01

GelitaSpon gelatin sponge (GS) showed faster reabsorption than gelfoam (GF) in vitro, and GS-packed middle ears resulted in a faster hearing recovery and less inflammation than the ears packed with GF soaked in saline. Soaking GF sponges with boric acid (BA) appeared to offset the inflammatory response of saline-soaked GF, making this inflammatory response comparable to that of GS-packed ears. To describe the reabsorption and inflammatory effects of absorbable gelatin sponge in the middle ear. For in vitro evaluation, GF and GS were used as disks immersed in saline solution or 3% BA and placed in gel. Images were captured with a microscope and processed using image processing Toolbox. For in vivo tests, 16 female albino Sprague Dawley rats were divided into four groups: bulla opening; GF + 0.9% saline; GF + BA; and GS + 0.9% saline. An anterior approach to the right bulla was used for surgery. Preoperative and postoperative auditory brainstem response thresholds were measured. In vitro, there was marked degradation of GF by day 14, while GS showed complete degradation by the third day. In vivo, hearing recovery occurred by day 21. GF produced a more severe inflammatory response, which could be reduced by treating the GF with BA.

Neurotrophic factor intervention restores auditory function in deafened animals

NASA Astrophysics Data System (ADS)

Shinohara, Takayuki; Bredberg, Göran; Ulfendahl, Mats; Pyykkö, Ilmari; Petri Olivius, N.; Kaksonen, Risto; Lindström, Bo; Altschuler, Richard; Miller, Josef M.

2002-02-01

A primary cause of deafness is damage of receptor cells in the inner ear. Clinically, it has been demonstrated that effective functionality can be provided by electrical stimulation of the auditory nerve, thus bypassing damaged receptor cells. However, subsequent to sensory cell loss there is a secondary degeneration of the afferent nerve fibers, resulting in reduced effectiveness of such cochlear prostheses. The effects of neurotrophic factors were tested in a guinea pig cochlear prosthesis model. After chemical deafening to mimic the clinical situation, the neurotrophic factors brain-derived neurotrophic factor and an analogue of ciliary neurotrophic factor were infused directly into the cochlea of the inner ear for 26 days by using an osmotic pump system. An electrode introduced into the cochlea was used to elicit auditory responses just as in patients implanted with cochlear prostheses. Intervention with brain-derived neurotrophic factor and the ciliary neurotrophic factor analogue not only increased the survival of auditory spiral ganglion neurons, but significantly enhanced the functional responsiveness of the auditory system as measured by using electrically evoked auditory brainstem responses. This demonstration that neurotrophin intervention enhances threshold sensitivity within the auditory system will have great clinical importance for the treatment of deaf patients with cochlear prostheses. The findings have direct implications for the enhancement of responsiveness in deafferented peripheral nerves.

Working memory capacity and visual-verbal cognitive load modulate auditory-sensory gating in the brainstem: toward a unified view of attention.

PubMed

Sörqvist, Patrik; Stenfelt, Stefan; Rönnberg, Jerker

2012-11-01

Two fundamental research questions have driven attention research in the past: One concerns whether selection of relevant information among competing, irrelevant, information takes place at an early or at a late processing stage; the other concerns whether the capacity of attention is limited by a central, domain-general pool of resources or by independent, modality-specific pools. In this article, we contribute to these debates by showing that the auditory-evoked brainstem response (an early stage of auditory processing) to task-irrelevant sound decreases as a function of central working memory load (manipulated with a visual-verbal version of the n-back task). Furthermore, individual differences in central/domain-general working memory capacity modulated the magnitude of the auditory-evoked brainstem response, but only in the high working memory load condition. The results support a unified view of attention whereby the capacity of a late/central mechanism (working memory) modulates early precortical sensory processing.

Auditory function in normal-hearing, noise-exposed human ears

PubMed Central

Stamper, Greta C.; Johnson, Tiffany A.

2014-01-01

Objectives To determine if supra-threshold measures of auditory function, such as distortion-product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs), are correlated with noise exposure history in normal-hearing human ears. Recent data from animal studies have revealed significant deafferentation of auditory nerve fibers following full recovery from temporary noise-induced hearing loss (NIHL). Furthermore, these data report smaller ABR wave I amplitudes in noise-exposed animal ears when compared to non-noise exposed control animals or pre-noise exposure amplitudes in the same animal. It is unknown if a similar phenomenon exists in the normal-hearing, noise-exposed human ear. Design Thirty normal-hearing human subjects with a range of noise exposure backgrounds (NEBs) participated in this study. NEB was quantified by the use of a noise exposure questionnaire that extensively queried loud sound exposure over the previous 12 months. DPOAEs were collected at three f2’s (1, 2, and 4 kHz) over a range of L2’s. DPOAE stimulus level began at 80 dB FPL (forward-pressure level) and decreased in 10 dB steps. Two-channel ABRs were collected in response to click stimuli and 4 kHz tone bursts; one channel utilized an ipsilateral mastoid electrode and the other an ipsilateral tympanic membrane (TM) electrode. ABR stimulus level began at 90 dB nHL and was decreased in 10 dB steps. Amplitudes of waves I and V of the ABR were analyzed. Results A statistically significant relationship between ABR wave I amplitude and NEB was found for clicked-evoked ABRs recorded at a stimulus level of 90 dB nHL using a mastoid recording electrode. For this condition, ABR wave I amplitudes decreased as a function of NEB. Similar systematic trends were present for ABRs collected in response to clicks and 4 kHz tone bursts at additional supra-threshold stimulation levels (≥ 70 dB nHL). The relationship weakened and disappeared with decreases in stimulation level (≤ 60 dB nHL). Similar patterns were present for ABRs collected using a TM electrode. However, these relationships were not statistically significant and were weaker and more variable than those collected using a mastoid electrode. In contrast to the findings for ABR wave I, wave V amplitude was not significantly related to NEB. Furthermore, there was no evidence of a systematic relationship between supra-threshold DPOAEs and NEB. Conclusions A systematic trend of smaller ABR wave I amplitudes was found in normal-hearing human ears with greater amounts of voluntary NEB in response to supra-threshold clicks and 4 kHz tone bursts. These findings are consistent with data from previous work completed in animals, where the reduction in supra-threshold responses was a result of deafferentation of high-threshold/low-spontaneous rate auditory nerve fibers. These data suggest a similar mechanism might be operating in human ears following exposure to high sound levels. However, evidence of this damage is only apparent when examining supra-threshold wave I amplitude of the ABR. In contrast, supra-threshold DPOAE level was not significantly related to NEB. This was expected, given noise-induced auditory damage findings in animal ears did not extend to the outer hair cells, the generator for the DPOAE response. PMID:25350405

Pontine hyperperfusion in sporadic hyperekplexia

PubMed Central

Vetrugno, Roberto; Mascalchi, Mario; Vella, Alessandra; Nave, Riccardo Della; Guerrini, Laura; Vattimo, Angelo; del Giudice, Emanuele Miraglia; Plazzi, Giuseppe; D'Angelo, Roberto; Greco, Giovanni; Montagna, Pasquale

2007-01-01

Objective To explore with neuroimaging techniques the anatomical and functional correlates of sporadic hyperekplexia. Methods Two elderly women with sporadic hyperekplexia underwent neurophysiological assessment, MRI of the brain and proton magnetic resonance spectroscopy (1H‐MRS) of the brainstem and frontal lobes. Regional cerebral blood flow was investigated with single photon emission tomography (SPECT) during evoked startles and at rest. Results Both patients showed excessively large and non‐habituating startle responses. In both patients, MRI showed impingement of the brainstem by the vertebrobasilar artery, lack of frontal or brainstem abnormalities on 1H‐MRS and hyperperfusion in the dorsal pons and cingulate cortex, and superior frontal gyrus at SPECT during evoked startles. Conclusions In our patients with hyperekplexia, the vertebrobasilar arteries were found to impinge on the brainstem. Neurophysiological findings and neurofunctional imaging of evoked startles indicated a pontine origin of the movement disorder modulated by activation in cortical, especially frontal, areas. The neurofunctional correlates of evoked startles in human sporadic hyperekplexia are similar to those observed for the startle circuit in animals. PMID:17702784

Pontine hyperperfusion in sporadic hyperekplexia.

PubMed

Vetrugno, Roberto; Mascalchi, Mario; Vella, Alessandra; Della Nave, Riccardo; Guerrini, Laura; Vattimo, Angelo; del Giudice, Emanuele Miraglia; Plazzi, Giuseppe; D'Angelo, Roberto; Greco, Giovanni; Montagna, Pasquale

2007-09-01

To explore with neuroimaging techniques the anatomical and functional correlates of sporadic hyperekplexia. Two elderly women with sporadic hyperekplexia underwent neurophysiological assessment, MRI of the brain and proton magnetic resonance spectroscopy (1H-MRS) of the brainstem and frontal lobes. Regional cerebral blood flow was investigated with single photon emission tomography (SPECT) during evoked startles and at rest. Both patients showed excessively large and non-habituating startle responses. In both patients, MRI showed impingement of the brainstem by the vertebrobasilar artery, lack of frontal or brainstem abnormalities on 1H-MRS and hyperperfusion in the dorsal pons and cingulate cortex, and superior frontal gyrus at SPECT during evoked startles. In our patients with hyperekplexia, the vertebrobasilar arteries were found to impinge on the brainstem. Neurophysiological findings and neurofunctional imaging of evoked startles indicated a pontine origin of the movement disorder modulated by activation in cortical, especially frontal, areas. The neurofunctional correlates of evoked startles in human sporadic hyperekplexia are similar to those observed for the startle circuit in animals.

[Effects of electrical stimulation at acupoints in the distribution area of auricular vagus nerve combined with sound masking method on auditory brainstem response and neurotransmitters of inferior colliculus in rats of tinnitus].

PubMed

Yang, Songbai; Mei, Zhigang; Tan, Lingjing; Ma, Wenhan; Zhang, Dingqi; Wang, Zhaojun; Li, Tiantian; Huang, Kunyan; Cai, Sanjin

2016-05-01

To explore the effects of electrical stimulation at acupoints in the distribution area of auricular vagus nerve combined with sound masking on auditory brainstem response (ABR) and contents of neurotransmitters of γ-aminobutyric acid (γ-GABA), 5-hydroxytryptamine (5-HT) and acetyl choline (Ach) in inferior colliculus of tinnitus rats. Twenty-four male adult SD rats were randomized into a control group, a model group, a 7-d treatment group and a 15-d treatment group. Except the control group, rats in the remaining groups were treated with intraperitoneal injection of 10% salicylate sodium at a dose of 350 mg/kg to establish tinnitus model. Rats in the control group were treated with injection of 0.9% NaCl. Rats in the 7-d treatment group and 15-d treatment group were treated with electrical stimulation at "Shenmen (TF₄)" and "Yidan (CO₁₁)" in the distribution area of auricular vagus nerve combined with sound masking, once a day, for 7 days and 15 days. The SigGenRP software of TDT system was applied to provide voice for single ear and collect the signal, and the voice threshold of ABR was tested. The levels of γ-GABA, 5-HT and Ach in inferior colliculus of rats were detected by enzyme linked immunosorbent assay (ELISA) and compared. Compared with the model group, the threshold values of ABR in 12 kHz and 16 kHz voice stimulation in the 7-d treatment group were significantly lower all P < 0.05); the threshold values of ABR from 4 kHz to 28 kHz voice stimulation in the 15-d treatment group were signally reduced (P < 0.05, P < 0.01), which was more significant than those in the 7-d treatment group. The level of γ-GABA in the model group was significantly lower than that in the control group (P < 0.05), and that in the 15-d treatment group was apparently higher than that in the model group (P < 0.05). The level of 5-HT in the model group was markedly higher than that in the control group (P < 0.05), and that in the 7-d treatment group was lower than that in the model group (P < 0.05), while that in the 15-d treatment group was apparently higher than that in the model group (P < 0.05). The level of Ach in the model group was obviously; lower than that in the control group (P < 0.05), and that in the 7-d treatment group was higher than that in the model group (P < 0.05). Electrical stimulation at auricular vagus nerve combined with sound masking) could regulate the threshold of ABR, especially in the 15-d treatment group. This may be ascribed to modulating the levels of neurotransmitter of γ-GABA, 5-HT and Ach in inferior colliculus.

A nonlinear filter-bank model of the guinea-pig cochlear nerve: Rate responses

NASA Astrophysics Data System (ADS)

Sumner, Christian J.; O'Mard, Lowel P.; Lopez-Poveda, Enrique A.; Meddis, Ray

2003-06-01

The aim of this study is to produce a functional model of the auditory nerve (AN) response of the guinea-pig that reproduces a wide range of important responses to auditory stimulation. The model is intended for use as an input to larger scale models of auditory processing in the brain-stem. A dual-resonance nonlinear filter architecture is used to reproduce the mechanical tuning of the cochlea. Transduction to the activity on the AN is accomplished with a recently proposed model of the inner-hair-cell. Together, these models have been shown to be able to reproduce the response of high-, medium-, and low-spontaneous rate fibers from the guinea-pig AN at high best frequencies (BFs). In this study we generate parameters that allow us to fit the AN model to data from a wide range of BFs. By varying the characteristics of the mechanical filtering as a function of the BF it was possible to reproduce the BF dependence of frequency-threshold tuning curves, AN rate-intensity functions at and away from BF, compression of the basilar membrane at BF as inferred from AN responses, and AN iso-intensity functions. The model is a convenient computational tool for the simulation of the range of nonlinear tuning and rate-responses found across the length of the guinea-pig cochlear nerve.

The auditory enhancement effect is not reflected in the 80-Hz auditory steady-state response.

PubMed

Carcagno, Samuele; Plack, Christopher J; Portron, Arthur; Semal, Catherine; Demany, Laurent

2014-08-01

The perceptual salience of a target tone presented in a multitone background is increased by the presentation of a precursor sound consisting of the multitone background alone. It has been proposed that this "enhancement" phenomenon results from an effective amplification of the neural response to the target tone. In this study, we tested this hypothesis in humans, by comparing the auditory steady-state response (ASSR) to a target tone that was enhanced by a precursor sound with the ASSR to a target tone that was not enhanced. In order to record neural responses originating in the brainstem, the ASSR was elicited by amplitude modulating the target tone at a frequency close to 80 Hz. The results did not show evidence of an amplified neural response to enhanced tones. In a control condition, we measured the ASSR to a target tone that, instead of being perceptually enhanced by a precursor sound, was acoustically increased in level. This level increase matched the magnitude of enhancement estimated psychophysically with a forward masking paradigm in a previous experimental phase. We found that the ASSR to the tone acoustically increased in level was significantly greater than the ASSR to the tone enhanced by the precursor sound. Overall, our results suggest that the enhancement effect cannot be explained by an amplified neural response at the level of the brainstem. However, an alternative possibility is that brainstem neurons with enhanced responses do not contribute to the scalp-recorded ASSR.

Effects of the brominated flame retardant hexabromocyclododecane (HBCD) on dopamine-dependent behavior and brainstem auditory evoked potentials in a one-generation reproduction study in Wistar rats.

PubMed

Lilienthal, Hellmuth; van der Ven, Leo T M; Piersma, Aldert H; Vos, Josephus G

2009-02-25

Hexabromocyclododecane (HBCD) is a widely used brominated flame retardant which has been recently detected in many environmental matrices. Data from a subacute toxicity study indicated dose-related effects particularly on the pituitary thyroid-axis and retinoids in female rats. Brominated and chlorinated aromatic hydrocarbons are also reported to exert effects on the nervous system. Several investigations revealed a pronounced sensitivity of the dopaminergic system and auditory functions to polychlorinated biphenyls. Therefore, the present experiment should examine, whether or not HBCD affects these targets. Rats were exposed to 0, 0.1, 0.3, 1, 3, 10, 30 or 100 mg HBCD/kg body weight via the diet. Exposure started before mating and was continued during mating, gestation, lactation, and after weaning in offspring. Haloperidol-induced catalepsy and brainstem auditory evoked potentials (BAEPs) were used to assess dopamine-dependent behavior and hearing function in adult male and female offspring. On the catalepsy test, reduced latencies to movement onset were observed mainly in female offspring, indicating influences on dopamine-dependent behavior. The overall pattern of BAEP alterations, with increased thresholds and prolonged latencies of early waves, suggested a predominant cochlear effect. Effects were dose-dependent with lower bounds of benchmark doses (BMDL) between < or =1 and 10 mg/kg body weight for both catalepsy and BAEP thresholds. Tissue concentrations at the BMDL values obtained in this study were 3-4 orders of magnitude higher than current exposure levels in humans.

Systematic Morphometry of Catecholamine Nuclei in the Brainstem.

PubMed

Bucci, Domenico; Busceti, Carla L; Calierno, Maria T; Di Pietro, Paola; Madonna, Michele; Biagioni, Francesca; Ryskalin, Larisa; Limanaqi, Fiona; Nicoletti, Ferdinando; Fornai, Francesco

2017-01-01

Catecholamine nuclei within the brainstem reticular formation (RF) play a pivotal role in a variety of brain functions. However, a systematic characterization of these nuclei in the very same experimental conditions is missing so far. Tyrosine hydroxylase (TH) immune-positive cells of the brainstem correspond to dopamine (DA)-, norepinephrine (NE)-, and epinephrine (E)-containing cells. Here, we report a systematic count of TH-positive neurons in the RF of the mouse brainstem by using stereological morphometry. All these nuclei were analyzed for anatomical localization, rostro-caudal extension, volume, neuron number, neuron density, and mean neuronal area for each nucleus. The present data apart from inherent informative value wish to represent a reference for neuronal mapping in those studies investigating the functional anatomy of the brainstem RF. These include: the sleep-wake cycle, movement control, muscle tone modulation, mood control, novelty orienting stimuli, attention, archaic responses to internal and external stressful stimuli, anxiety, breathing, blood pressure, and innumerable activities modulated by the archaic iso-dendritic hard core of the brainstem RF. Most TH-immune-positive cells fill the lateral part of the RF, which indeed possesses a high catecholamine content. A few nuclei are medial, although conventional nosography considers all these nuclei as part of the lateral column of the RF. Despite the key role of these nuclei in psychiatric and neurological disorders, only a few of them aspired a great attention in biomedical investigation, while most of them remain largely obscure although intense research is currently in progress. A simultaneous description of all these nuclei is not simply key to comprehend the variety of brainstem catecholamine reticular neurons, but probably represents an intrinsically key base for understanding brain physiology and physiopathology.

Systematic Morphometry of Catecholamine Nuclei in the Brainstem

PubMed Central

Bucci, Domenico; Busceti, Carla L.; Calierno, Maria T.; Di Pietro, Paola; Madonna, Michele; Biagioni, Francesca; Ryskalin, Larisa; Limanaqi, Fiona; Nicoletti, Ferdinando; Fornai, Francesco

2017-01-01

Catecholamine nuclei within the brainstem reticular formation (RF) play a pivotal role in a variety of brain functions. However, a systematic characterization of these nuclei in the very same experimental conditions is missing so far. Tyrosine hydroxylase (TH) immune-positive cells of the brainstem correspond to dopamine (DA)-, norepinephrine (NE)-, and epinephrine (E)-containing cells. Here, we report a systematic count of TH-positive neurons in the RF of the mouse brainstem by using stereological morphometry. All these nuclei were analyzed for anatomical localization, rostro-caudal extension, volume, neuron number, neuron density, and mean neuronal area for each nucleus. The present data apart from inherent informative value wish to represent a reference for neuronal mapping in those studies investigating the functional anatomy of the brainstem RF. These include: the sleep-wake cycle, movement control, muscle tone modulation, mood control, novelty orienting stimuli, attention, archaic responses to internal and external stressful stimuli, anxiety, breathing, blood pressure, and innumerable activities modulated by the archaic iso-dendritic hard core of the brainstem RF. Most TH-immune-positive cells fill the lateral part of the RF, which indeed possesses a high catecholamine content. A few nuclei are medial, although conventional nosography considers all these nuclei as part of the lateral column of the RF. Despite the key role of these nuclei in psychiatric and neurological disorders, only a few of them aspired a great attention in biomedical investigation, while most of them remain largely obscure although intense research is currently in progress. A simultaneous description of all these nuclei is not simply key to comprehend the variety of brainstem catecholamine reticular neurons, but probably represents an intrinsically key base for understanding brain physiology and physiopathology. PMID:29163071

Respiratory responses to intermittent hypoxia in unsedated piglets: relation to substance P binding in brainstem.

PubMed

Laferrière, André; Moss, Immanuela Ravé

2004-10-12

Respiratory responses to single intermittent hypoxia (5 min 21% O(2), 5 min 8% O(2) X6) in 5-6, 10-11, 21-22 and 26-27 day-old piglets, and to recurrent six daily intermittent hypoxia in 10-11 and 26-27 day-old piglets were assessed. Substance P binding in the piglets' brainstem immediately after the last hypoxic episode was measured. All piglets hyperventilated during hypoxia. Weight adjusted inspired ventilation, tidal volume and instantaneous flow decreased with age. The oldest piglets uniquely displayed attenuated ventilation and tidal volume during the sixth versus first hypoxic episode with single intermittent hypoxia, and reduced inspired ventilation and tidal volume during the first hypoxic episode on the sixth daily hypoxia compared to single hypoxia. By contrast, substance P binding was greatly reduced in the solitary, hypoglossal, paraambigual and lateral reticular brainstem nuclei of both younger and older piglets following either single or recurrent intermittent hypoxia. Thus, the reduction in membrane-bound neurokinin receptors by intermittent hypoxia, presumably consequent to endogenously released substance P, does not exclusively determine whether the ventilatory response to that hypoxia will be attenuated or not.

Brainstem encoding of speech and musical stimuli in congenital amusia: evidence from Cantonese speakers

PubMed Central

Liu, Fang; Maggu, Akshay R.; Lau, Joseph C. Y.; Wong, Patrick C. M.

2015-01-01

Congenital amusia is a neurodevelopmental disorder of musical processing that also impacts subtle aspects of speech processing. It remains debated at what stage(s) of auditory processing deficits in amusia arise. In this study, we investigated whether amusia originates from impaired subcortical encoding of speech (in quiet and noise) and musical sounds in the brainstem. Fourteen Cantonese-speaking amusics and 14 matched controls passively listened to six Cantonese lexical tones in quiet, two Cantonese tones in noise (signal-to-noise ratios at 0 and 20 dB), and two cello tones in quiet while their frequency-following responses (FFRs) to these tones were recorded. All participants also completed a behavioral lexical tone identification task. The results indicated normal brainstem encoding of pitch in speech (in quiet and noise) and musical stimuli in amusics relative to controls, as measured by FFR pitch strength, pitch error, and stimulus-to-response correlation. There was also no group difference in neural conduction time or FFR amplitudes. Both groups demonstrated better FFRs to speech (in quiet and noise) than to musical stimuli. However, a significant group difference was observed for tone identification, with amusics showing significantly lower accuracy than controls. Analysis of the tone confusion matrices suggested that amusics were more likely than controls to confuse between tones that shared similar acoustic features. Interestingly, this deficit in lexical tone identification was not coupled with brainstem abnormality for either speech or musical stimuli. Together, our results suggest that the amusic brainstem is not functioning abnormally, although higher-order linguistic pitch processing is impaired in amusia. This finding has significant implications for theories of central auditory processing, requiring further investigations into how different stages of auditory processing interact in the human brain. PMID:25646077

Developmental study of the distribution of hypoxia-induced factor-1 alpha and microtubule-associated protein 2 in children's brainstem: comparison between controls and cases with signs of perinatal hypoxia.

PubMed

Coveñas, R; González-Fuentes, J; Rivas-Infante, E; Lagartos-Donate, M J; Cebada-Sánchez, S; Arroyo-Jiménez, M M; Insausti, R; Marcos, P

2014-06-20

Perinatal asphyxia and hypoxia are common causes of morbidity in neonates. Prenatal birth associated with hypoxemia often results in several disorders because of the lack of oxygen in the brain. Survival rates from perinatal hypoxia have improved, but appropriate treatments for recovery are still limited, with great impact on patients, their families, society in general and health systems. The aim of this work is to contribute to a better understanding of the cellular mechanisms underlying the brainstem responses to hypoxia. For this purpose, distributions of two proteins, hypoxia-inducible factor-1 alpha (HIF-1α) and microtubule-associated protein 2 (MAP-2) were analyzed in brainstems of 11 children, four of them showing neuropathological evidence of brain hypoxia. They were included in control or hypoxic groups, and then in several subgroups according to their age. Immunohistochemical labeling for these proteins revealed only cell bodies containing HIF-1α, and both cell bodies and fibers positive for MAP-2 in the children's brainstems. The distribution of HIF-1α was more restricted than that of MAP-2, and it can be suggested that the expression of HIF-1α increased with age. The distribution pattern of MAP-2 in the medulla oblongata could be more due to age-related changes than to a response to hypoxic damage, whereas in the pons several regions, such as the nucleus ambiguus or the solitary nucleus, showed different immunolabeling patterns in controls and hypoxic cases. The distribution patterns of these two proteins suggest that some brainstem regions, such as the reticular formation or the central gray, could be less affected by conditions of hypoxia. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Brainstem encoding of speech and musical stimuli in congenital amusia: evidence from Cantonese speakers.

PubMed

Liu, Fang; Maggu, Akshay R; Lau, Joseph C Y; Wong, Patrick C M

2014-01-01

Congenital amusia is a neurodevelopmental disorder of musical processing that also impacts subtle aspects of speech processing. It remains debated at what stage(s) of auditory processing deficits in amusia arise. In this study, we investigated whether amusia originates from impaired subcortical encoding of speech (in quiet and noise) and musical sounds in the brainstem. Fourteen Cantonese-speaking amusics and 14 matched controls passively listened to six Cantonese lexical tones in quiet, two Cantonese tones in noise (signal-to-noise ratios at 0 and 20 dB), and two cello tones in quiet while their frequency-following responses (FFRs) to these tones were recorded. All participants also completed a behavioral lexical tone identification task. The results indicated normal brainstem encoding of pitch in speech (in quiet and noise) and musical stimuli in amusics relative to controls, as measured by FFR pitch strength, pitch error, and stimulus-to-response correlation. There was also no group difference in neural conduction time or FFR amplitudes. Both groups demonstrated better FFRs to speech (in quiet and noise) than to musical stimuli. However, a significant group difference was observed for tone identification, with amusics showing significantly lower accuracy than controls. Analysis of the tone confusion matrices suggested that amusics were more likely than controls to confuse between tones that shared similar acoustic features. Interestingly, this deficit in lexical tone identification was not coupled with brainstem abnormality for either speech or musical stimuli. Together, our results suggest that the amusic brainstem is not functioning abnormally, although higher-order linguistic pitch processing is impaired in amusia. This finding has significant implications for theories of central auditory processing, requiring further investigations into how different stages of auditory processing interact in the human brain.

Evaluation of the thoraco-laryngeal reflex ('slap test') as an aid to the diagnosis of cervical spinal cord and brainstem disease in horses.

PubMed

Newton-Clarke, M J; Divers, T J; Delahunta, A; Mohammed, H O

1994-09-01

A study was conducted over a 12 month period to assess the specificity and sensitivity of the 'slap test', using endoscopic evaluation, in the detection of cervical spinal cord and caudal brainstem lesions in horses. Fifteen ataxic horses were subjected to the 'slap test' and subsequently examined post mortem. Twelve out of the 15 had histopathological lesions consistent with their clinical signs. Thirteen horses with no history of neurological dysfunction and no histopathological evidence of cervical spinal cord or brainstem disease were used as controls. The laryngeal adductory responses exhibited by all horses were filmed and later scored independently by 3 assessors. The proportion of animals diagnosed with cervical spinal cord and/or brainstem disease, defined by histopathological criteria, was found to be statistically similar to the proportion with abnormal 'slap test' responses, using the McNemar chi-Square test. Despite statistical significance between proportions, sensitivity of the 'slap test' was low, 50% for the left side on both days and 58% for the right side. Specificity was higher, 69% (Day 1) and 75% (Day 2) for the left side and 75% (Day 1) and 69% (Day 2) for the right side. In contrast to this, conventional neurological examination was found to be 100% sensitive and 81% specific in the detection of lesions of histopathological significance in the cervical spinal cord/caudal brainstem. Agreement between scores for the 'slap test' from the same assessor on different days was good, with values for kappa of 0.59 to 0.85. In contrast, agreement between assessors on the 'slap test' score was poor, with kappa 0.35.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of mild traumatic brain injury on auditory brain stem dysfunction in mouse model.

PubMed

Amanipour, Reza M; Frisina, Robert D; Cresoe, Samantha A; Parsons, Teresa J; Xiaoxia Zhu; Borlongan, Cesario V; Walton, Joseph P

2016-08-01

The auditory brainstem response (ABR) is an electrophysiological test that examines the functionality of the auditory nerve and brainstem. Traumatic brain injury (TBI) can be detected if prolonged peak latency is observed in ABR measurements, since latency measures the neural conduction time in the brainstem, and an increase in latency can be a sign of pathological lesion at the auditory brainstem level. The ABR is elicited by brief sounds that can be used to measure hearing sensitivity as well as temporal processing. Reduction in peak amplitudes and increases in latency are indicative of dysfunction in the auditory nerve and/or central auditory pathways. In this study we used sixteen young adult mice that were divided into two groups: sham and mild traumatic brain injury (mTBI), with ABR measurements obtained prior to, and at 2, 6, and 14 weeks after injury. Abnormal ABRs were observed for the nine TBI cases as early as two weeks after injury and the deficits lasted for fourteen weeks after injury. Results indicated a significant reduction in the Peak 1 (P1) and Peak 4 (P4) amplitudes to the first noise burst, as well as an increase in latency response for P1 and P4 following mTBI. These results are the first to demonstrate auditory sound processing deficits in a rodent model of mild TBI.

Abnormal findings in brainstem auditory evoked response at 36-37weeks of postconceptional age in babies with neonatal chronic lung disease.

PubMed

Jiang, Ze D; Wang, Cui

2016-12-01

To examine brainstem auditory function at 36-37weeks of postconceptional age in preterm infants who are diagnosed to have neonatal chronic lung disease (CLD). Preterm infants, born at 31 and less weeks of gestation, were studied at 36-37weeks of postconceptional age when they were diagnosed to have neonatal CLD. Brainstem auditory evoked response (BAER) was recorded and analyzed at different click rates. Compared with healthy controls at the same postconceptional age, the CLD infants showed a slightly increase in BAER wave V latency. However, the I-V, and III-V interpeak intervals in the CLD infants were significantly increased. The III-V/I-III interval ratio was also significantly increased. The amplitudes of BAER waves III and V in the CLD infants tended to be reduced. These BAER findings were similar at all 21, 51 and 91/s clicks, although the abnormalities tended to be more significant at higher than at low click rates. At 36-37weeks of postconceptional age, BAER was abnormal in preterm infants who were diagnosed to have neonatal CLD. This suggests that at time when the diagnosis of CLD is made there is functional impairment, reflecting poor myelination, in the brainstem auditory pathway in preterm infants with neonatal CLD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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.

Examining the role of the tectorial membrane in otoacoustic emission generation

NASA Astrophysics Data System (ADS)

Cheatham, Marry Ann; Goodyear, Richard J.; Charaziak, Karolina K.; Conklin, Tess; Zheng, Jing; Dallos, Peter; Richardson, Guy P.; Siegel, Jonathan H.

2015-12-01

A mouse lacking CEACAM16, a member of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family of proteins, shows changes in tectorial membrane (TM) structure including loss of a defined striated-sheet matrix, absence of Hensen's stripe and increased porosity. In spite of these changes, thresholds for distortion product emissions (DPOAEs) and auditory brainstem responses (ABR) are near normal for most frequencies in the mouse audiogram [11]. In contrast, stimulus frequency emissions (SFOAE) are larger in knockouts (KO) and the incidence of spontaneous emissions (SOAE) is ˜70% [5]. This latter statistic is remarkable considering that SOAEs are uncommon in normal wild-type (WT) mice. In order to understand how the TM might influence emissions, SFOAE magnitude and phase were examined and group delays computed. As in humans, an approximately one-cycle phase change is observed in association with SFOAE fine structure. In addition, CEACAM16 KO mice and their WT controls showed similar group delays/phase slopes indicating no obvious changes in the mechanisms associated with emission generation.

D-METHIONINE REDUCES TOBRAMYCIN-INDUCED OTOTOXICITY WITHOUT ANTIMICROBIAL INTERFERENCE IN ANIMAL MODELS

PubMed Central

Fox, Daniel J.; Cooper, Morris D.; Speil, Cristian A.; Roberts, Melissa H.; Yanik, Susan C.; Meech, Robert P.; Hargrove, Tim L.; Verhulst, Steven J.; Rybak, Leonard P.; Campbell, Kathleen C. M.

2015-01-01

Background Tobramycin is a critical cystic fibrosis treatment however it causes ototoxicity. This study tested D-methionine protection from tobramycin-induced ototoxicity and potential antimicrobial interference. Methods Auditory brainstem responses (ABR) and outer hair cell (OHC) quantifications measured protection in guinea pigs treated with tobramycin and a range of D-methionine doses. In vitro antimicrobial interference studies tested inhibition and post antibiotic effect assays. In vivo antimicrobial interference studies tested normal and neutropenic E. coli murine survival and intraperitoneal lavage bacterial counts. Results D-methionine conferred significant ABR threshold shift reductions. OHC protection was less robust but significant at 20 kHz in the 420 mg/kg/day group. In vitro studies did not detect D-methionine-induced antimicrobial interference. In vivo studies did not detect D-methionine-induced interference in normal or neutropenic mice. Conclusions D-methionine protects from tobramycin-induced ototoxicity without antimicrobial interference. The study results suggest D-met as a potential otoprotectant from clinical tobramycin use in cystic fibrosis patients. PMID:26166286

Effects of coil orientation and magnetic field shield on transcranial magnetic stimulation in cats.

PubMed

Nakatoh, S; Kitagawa, H; Kawaguchi, Y; Nakamura, H; Takano, H; Tsuji, H

1998-09-01

To obtain suitable stimulus conditions for transcranial magnetic stimulation, the evoked compound muscle action potential (ECMAP), evoked spinal cord potential (ESCP), and magnetic and electric fields were analyzed in cats with and without the use of a magnetic field shield. Cats were stimulated using a figure 8 magnetic coil placed on the cranium above the motor cortex. The maximum ECMAP amplitude was recorded when the electric current in the coil was in the mediolateral direction, regardless of whether a magnetic shield with a 5 x 5 cm window was used. ECMAP and ESCP thresholds were reduced when magnetic shielding was in place. Due to the edge effect, the strengths of the magnetic and electric fields were highest in the brainstem area, which is an inhomogeneous volume conductor of the cat's cranium. A large induced electric field directed caudally elicited ECMAP and ESCP responses effectively when a magnetic shield with a 5 x 5 cm window was in place.

d-Methionine reduces tobramycin-induced ototoxicity without antimicrobial interference in animal models.

PubMed

Fox, Daniel J; Cooper, Morris D; Speil, Cristian A; Roberts, Melissa H; Yanik, Susan C; Meech, Robert P; Hargrove, Tim L; Verhulst, Steven J; Rybak, Leonard P; Campbell, Kathleen C M

2016-07-01

Tobramycin is a critical cystic fibrosis treatment however it causes ototoxicity. This study tested d-methionine protection from tobramycin-induced ototoxicity and potential antimicrobial interference. Auditory brainstem responses (ABRs) and outer hair cell (OHC) quantifications measured protection in guinea pigs treated with tobramycin and a range of d-methionine doses. In vitro antimicrobial interference studies tested inhibition and post antibiotic effect assays. In vivo antimicrobial interference studies tested normal and neutropenic Escherichia coli murine survival and intraperitoneal lavage bacterial counts. d-Methionine conferred significant ABR threshold shift reductions. OHC protection was less robust but significant at 20kHz in the 420mg/kg/day group. In vitro studies did not detect d-methionine-induced antimicrobial interference. In vivo studies did not detect d-methionine-induced interference in normal or neutropenic mice. d-Methionine protects from tobramycin-induced ototoxicity without antimicrobial interference. The study results suggest d-met as a potential otoprotectant from clinical tobramycin use in cystic fibrosis patients. Published by Elsevier B.V.

Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

NASA Technical Reports Server (NTRS)

Hecox, K.; Squires, N.; Galambos, R.

1975-01-01

Short latency (under 10 msec) responses elicited by bursts of white noise were recorded from the scalps of human subjects. Response alterations produced by changes in the noise burst duration (on-time), inter-burst interval (off-time), and onset and offset shapes were analyzed. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise time but was unaffected by changes in fall time. Increases in stimulus duration, and therefore in loudness, resulted in a systematic increase in latency. This was probably due to response recovery processes, since the effect was eliminated with increases in stimulus off-time. The amplitude of wave V was insensitive to changes in signal rise and fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It was concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

Age-related changes in the auditory brainstem response.

PubMed

Konrad-Martin, Dawn; Dille, Marilyn F; McMillan, Garnett; Griest, Susan; McDermott, Daniel; Fausti, Stephen A; Austin, Donald F

2012-01-01

This cross-sectional study had two goals: (1) Identify and quantify the effects of aging on the auditory brainstem response (ABR); (2) Describe how click rate and hearing impairment modify effects of aging. RESEARCH DESIGN AND ANALYSIS: ABR measures were obtained from 131 predominately male Veteran participants aged 26 to 71 yr. Metrics analyzed include amplitude and latency for waves I, III, and V, and the I-V interpeak latency interval (IPI) at three repetition rates (11, 51, and 71 clicks/sec) using both polarities. In order to avoid confounding from missing data due to hearing impairment, participants had hearing thresholds <40 dB HL at 2 kHz and 70 dB HL at 4 kHz in at least one ear. Additionally, the median 2, 3, and 4 kHz pure tone threshold average (PTA2,3,4) for the sample, ∼17 dB HL, was used to delineate subgroups of better and worse hearing ears, and only the better hearing sample was modeled statistically. We modeled ABR responses using age, repetition rate, and PTA2,3,4 as covariates. Random effects were used to model correlation between the two ears of a subject and across repetition rates. Inferences regarding effects of aging on ABR measures at each rate were derived from the fitted model. Results were compared to data from subjects with poorer hearing. Aging substantially diminished amplitudes of all of the principal ABR peaks, largely independent of any threshold differences within the group. For waves I and III, age-related amplitude decrements were greatest at a low (11/sec) click rate. At the 11/sec rate, the model-based mean wave III amplitude was significantly smaller in older compared with younger subjects even after adjusting for wave I amplitude. Aging also increased ABR peak latencies, with significant shifts limited to early waves. The I-V IPI did not change with age. For both younger and older subjects, increasing click presentation rate significantly decreased amplitudes of early peaks and prolonged latencies of later peaks, resulting in increased IPIs. Advanced age did not enhance effects of rate. Instead, the rate effect on wave I and III amplitudes was attenuated for the older subjects due to reduced peak amplitudes at lower click rates. Compared with model predictions from the sample of better hearing subjects, mean ABR amplitudes were diminished in the group with poorer hearing, and wave V latencies were prolonged. In a sample of veterans, aging substantially reduced amplitudes of all principal ABR peaks, with significant latency shifts limited to waves I and III. Aging did not influence the I-V IPI even at high click rates, suggesting that the observed absolute latency changes associated with aging can be attributed to changes in auditory nerve input. In contrast, ABR amplitude changes with age are not adequately explained by changes in wave I. Results suggest that aging reduces the numbers and/or synchrony of contributing auditory nerve units. Results also support the concept that aging reduces the numbers, though perhaps not the synchrony, of central ABR generators. American Academy of Audiology.

Mechanical damage of tympanic membrane in relation to impulse pressure waveform - A study in chinchillas.

PubMed

Gan, Rong Z; Nakmali, Don; Ji, Xiao D; Leckness, Kegan; Yokell, Zachary

2016-10-01

Mechanical damage to middle ear components in blast exposure directly causes hearing loss, and the rupture of the tympanic membrane (TM) is the most frequent injury of the ear. However, it is unclear how the severity of injury graded by different patterns of TM rupture is related to the overpressure waveforms induced by blast waves. In the present study, the relationship between the TM rupture threshold and the impulse or overpressure waveform has been investigated in chinchillas. Two groups of animals were exposed to blast overpressure simulated in our lab under two conditions: open field and shielded with a stainless steel cup covering the animal head. Auditory brainstem response (ABR) and wideband tympanometry were measured before and after exposure to check the hearing threshold and middle ear function. Results show that waveforms recorded in the shielded case were different from those in the open field and the TM rupture threshold in the shielded case was lower than that in the open field (3.4 ± 0.7 vs. 9.1 ± 1.7 psi or 181 ± 1.6 vs. 190 ± 1.9 dB SPL). The impulse pressure energy spectra analysis of waveforms demonstrates that the shielded waveforms include greater energy at high frequencies than that of the open field waves. Finally, a 3D finite element (FE) model of the chinchilla ear was used to compute the distributions of stress in the TM and the TM displacement with impulse pressure waves. The FE model-derived change of stress in response to pressure loading in the shielded case was substantially faster than that in the open case. This finding provides the biomechanical mechanisms for blast induced TM damage in relation to overpressure waveforms. The TM rupture threshold difference between the open and shielded cases suggests that an acoustic role of helmets may exist, intensifying ear injury during blast exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Central nervous system prostaglandin endoperoxide synthase-1 and −2 responses to oestradiol and cerebral hypoperfusion in late-gestation fetal sheep

PubMed Central

Wood, Charles E; Giroux, Damian

2003-01-01

Previous work in this laboratory has demonstrated that cerebral hypoperfusion increases the expression of prostaglandin endoperoxide synthase-2 (PGHS-2) in ovine fetal brain regions. Endogenously produced prostaglandins, in turn, partially mediate the fetal hypothalamus- pituitary-adrenal (HPA) axis response to arterial hypotension. In separate experiments, we have found that oestradiol stimulates fetal HPA axis activity. The present experiments were designed to test the hypothesis that oestradiol increases the expression of PGHS isoforms, and that oestradiol augments the PGHS response to cerebral hypoperfusion. Sixteen fetal sheep of known gestational ages (124–128 days' gestation at the time of study) were subjected to chronic catheterization and implantation of extravascular occluder around the brachiocephalic artery. Eight fetuses were subjected to subcutaneous implantation of a pellet containing 17β-oestradiol (release rate 5 mg (21 days)−1). Brachiocephalic occlusion (BCO) stimulated adrenocorticotropin (ACTH), cortisol and arginine vasopressin (AVP) secretion, responses that were augmented by oestradiol. One hour after the beginning of a 10 min period of BCO, PGHS-1 mRNA was increased in fetal brainstem and hypothalamus, and PGHS-2 mRNA was increased in fetal brainstem. Oestradiol, by itself, increased the abundance of PGHS-2 mRNA in brainstem and cerebellum, and augmented the PGHS-2 mRNA response to BCO in brainstem. In contrast, oestradiol had no significant effect on the abundance of PGHS-1 mRNA in any brain region. PGHS-1 and PGHS-2 protein levels did not reflect the changes in the respective mRNAs. The abundance of both proteins was increased in cerebral cortex in response to BCO, and the abundance of PGHS-2 protein was increased by both oestradiol and BCO in the hippocampus. The results of this study confirm and extend the results of our previous studies, demonstrating an effect of cerebral hypoperfusion on the expression of both isoforms of PGHS. We conclude that oestradiol increases the expression of PGHS-2 in specific fetal brain regions, and that there is an interaction between oestradiol and BCO in the control of PGHS-2 expression in the fetal brainstem. We expect that at later time-points, the changes in mRNA would be followed by similar changes in enzyme abundance at the protein level. We speculate that at least a part of the effect of oestradiol on fetal HPA axis function is mediated by an interaction between oestradiol and prostaglandin biosynthesis in the fetal brain. PMID:12702743

The Time Course of Deafness and Retinal Degeneration in a Kunming Mouse Model for Usher Syndrome.

PubMed

Yao, Lu; Zhang, Lei; Qi, Lin-Song; Liu, Wei; An, Jing; Wang, Bin; Xue, Jun-Hui; Zhang, Zuo-Ming

2016-01-01

Usher syndrome is a group of autosomal recessive diseases characterized by congenital deafness and retinitis pigmentosa. In a mouse model for Usher syndrome, KMush/ush, discovered in our laboratory, we measured the phenotypes, characterized the architecture and morphology of the retina, and quantified the level of expression of pde6b and ush2a between postnatal (P) days 7, and 56. Electroretinograms and auditory brainstem response were used to measure visual and auditory phenotypes. Fundus photography and light microscopy were used to measure the architecture and morphology of the retina. Quantitative real-time PCR was used to measure the expression levels of mRNA. KMush/ush mice had low amplitudes and no obvious waveforms of Electroretinograms after P14 compared with controls. Thresholds of auditory brainstem response in our model were higher than those of controls after P14. By P21, the retinal vessels of KMush/ush mice were attenuated and their optic discs had a waxy pallor. The retinas of KMush/ush mice atrophied and the choroidal vessels were clearly visible. Notably, the architecture of each retinal layer was not different as compared with control mice at P7, while the outer nuclear layer (ONL) and other retinal layers of KMush/ush mice were attenuated significantly between P14 and P21. ONL cells were barely seen in KMush/ush mice at P56. As compared with control mice, the expression of pde6b and ush2a in KMush/ush mice declined significantly after P7. This study is a first step toward characterizing the progression of disease in our mouse model. Future studies using this model may provide insights about the etiology of the disease and the relationships between genotypes and phenotypes providing a valuable resource that could contribute to the foundation of knowledge necessary to develop therapies to prevent the retinal degeneration in patients with Usher Syndrome.

Inter- and intrapatient variability of facial nerve response areas in the floor of the fourth ventricle.

PubMed

Bertalanffy, Helmut; Tissira, Nadir; Krayenbühl, Niklaus; Bozinov, Oliver; Sarnthein, Johannes

2011-03-01

Surgical exposure of intrinsic brainstem lesions through the floor of the 4th ventricle requires precise identification of facial nerve (CN VII) fibers to avoid damage. To assess the shape, size, and variability of the area where the facial nerve can be stimulated electrophysiologically on the surface of the rhomboid fossa. Over a period of 18 months, 20 patients were operated on for various brainstem and/or cerebellar lesions. Facial nerve fibers were stimulated to yield compound muscle action potentials (CMAP) in the target muscles. Using the sites of CMAP yield, a detailed functional map of the rhomboid fossa was constructed for each patient. Lesions resected included 14 gliomas, 5 cavernomas, and 1 epidermoid cyst. Of 40 response areas mapped, 19 reached the median sulcus. The distance from the obex to the caudal border of the response area ranged from 8 to 27 mm (median, 17 mm). The rostrocaudal length of the response area ranged from 2 to 15 mm (median, 5 mm). Facial nerve response areas showed large variability in size and position, even in patients with significant distance between the facial colliculus and underlying pathological lesion. Lesions located close to the facial colliculus markedly distorted the response area. This is the first documentation of variability in the CN VII response area in the rhomboid fossa. Knowledge of this remarkable variability may facilitate the assessment of safe entry zones to the brainstem and may contribute to improved outcome following neurosurgical interventions within this sensitive area of the brain.

The Physiological Basis and Clinical Use of the Binaural Interaction Component of the Auditory Brainstem Response

PubMed Central

Klump, Georg M.; Tollin, Daniel J.

2016-01-01

The auditory brainstem response (ABR) is a sound-evoked non-invasively measured electrical potential representing the sum of neuronal activity in the auditory brainstem and midbrain. ABR peak amplitudes and latencies are widely used in human and animal auditory research and for clinical screening. The binaural interaction component (BIC) of the ABR stands for the difference between the sum of the monaural ABRs and the ABR obtained with binaural stimulation. The BIC comprises a series of distinct waves, the largest of which (DN1) has been used for evaluating binaural hearing in both normal hearing and hearing-impaired listeners. Based on data from animal and human studies, we discuss the possible anatomical and physiological bases of the BIC (DN1 in particular). The effects of electrode placement and stimulus characteristics on the binaurally evoked ABR are evaluated. We review how inter-aural time and intensity differences affect the BIC and, analyzing these dependencies, draw conclusion about the mechanism underlying the generation of the BIC. Finally, the utility of the BIC for clinical diagnoses are summarized. PMID:27232077

Electroretinogram (ERG) to photic stimuli should be carefully distinct from photic brainstem reflex in patients with deep coma.

PubMed

Mitsuhashi, Masahiro; Hitomi, Takefumi; Aoyama, Akihiro; Kaido, Toshimi; Ikeda, Akio; Takahashi, Ryosuke

2017-08-31

Patient 1: A 35-year-old woman became deep coma because of intracranial hemorrhage after pulmonary surgery. Patient 2: A 39-year-old woman became deep coma because of cerebellar hemorrhage after hepatic surgery. Scalp-recorded digital electroencephalography (EEG) showed electrocerebral inactivity in both cases. In addition, both EEG showed repetitive discharges at bilateral frontopolar electrodes in response to photic stimuli. The amplitude and latency of the discharges was 17 μV and 24 msec in case 1, and 9 μV and 27 msec in case 2 respectively. The activity at left frontopolar electrode disappeared after coverage of the ipsilateral eye. Based on these findings, we could exclude the possibility of brainstem response and judged it as electroretinogram (ERG). Photic stimulation is a useful activation method in EEG recording, and we can also evaluate brainstem function by checking photic blink reflex if it is evoked. However, we should be cautious about the distinction of ERG from photic blink reflex when brain death is clinically suspected.

Efficacy of carnitine in treatment of tinnitus: evidence from audiological and MRI measures-a case study.

PubMed

Gopal, Kamakshi V; Thomas, Binu P; Mao, Deng; Lu, Hanzhang

2015-03-01

Tinnitus, or ringing in the ears, is an extremely common ear disorder. However, it is a phenomenon that is very poorly understood and has limited treatment options. The goals of this case study were to identify if the antioxidant acetyl-L-carnitine (ALCAR) provides relief from tinnitus, and to identify if subjective satisfaction after carnitine treatment is accompanied by changes in audiological and imaging measures. Case Study. A 41-yr-old female with a history of hearing loss and tinnitus was interested in exploring the benefits of antioxidant therapy in reducing her tinnitus. The patient was evaluated using a standard audiological/tinnitus test battery and magnetic resonance imaging (MRI) recordings before carnitine treatment. After her physician's approval, the patient took 500 mg of ALCAR twice a day for 30 consecutive days. The audiological and MRI measures were repeated after ALCAR treatment. Pure-tone audiometry, tympanometry, distortion-product otoacoustic emissions, tinnitus questionnaires (Tinnitus Handicap Inventory and Tinnitus Reaction Questionnaire), auditory brainstem response, functional MRI (fMRI), functional connectivity MRI, and cerebral blood flow evaluations were conducted before intake of ALCAR and were repeated 30 days after ALCAR treatment. The patient's pretreatment pure-tone audiogram indicated a mild sensorineural hearing loss at 6 kHz in the right ear and 4 kHz in the left ear. Posttreatment evaluation indicated marginal improvement in the patient's pure-tone thresholds, but was sufficient to be classified as being clinically normal in both ears. Distortion-product otoacoustic emissions results showed increased overall emissions after ALCAR treatment. Subjective report from the patient indicated that her tinnitus was less annoying and barely noticeable during the day after treatment, and the posttreatment tinnitus questionnaire scores supported her statement. Auditory brainstem response peak V amplitude growth between stimulus intensity levels of 40-80 dB nHL indicated a reduction in growth for the posttreatment condition compared with the pretreatment condition. This was attributed to a possible active gating mechanism involving the auditory brainstem after ALCAR treatment. Posttreatment fMRI recordings in response to acoustic stimuli indicated a statistically significant reduction in brain activity in several regions of the brain, including the auditory cortex. Cerebral blood flow showed increased flow in the auditory cortex after treatment. The functional connectivity MRI indicated increased connectivity between the right and left auditory cortex, but a decrease in connectivity between the auditory cortex and some regions of the "default mode network," namely the medial prefrontal cortex and posterior cingulate cortex. The changes observed in the objective and subjective test measures after ALCAR treatment, along with the patient's personal observations, indicate that carnitine intake may be a valuable pharmacological option in the treatment of tinnitus. American Academy of Audiology.

Increased endothelial progenitor cell circulation and VEGF production in a rat model of noise-induced hearing loss.

PubMed

Yang, Dong; Zhou, Huifang; Zhang, Jianning; Liu, Li

2015-06-01

The vascular endothelial growth factor (VEGF)-mediated mechanism of endothelial progenitor cell (EPC) mobilization, migration, and differentiation may occur in response to noise-induced acoustic trauma of the cochlea, leading to the protection of cochlear function. The purpose of this study was to analyze changes in the cochlear vessel under an intensive noise environment. Sixty male Sprague-Dawley rats were randomly divided into six groups. Acoustic trauma was induced by 120 dB SPL white noise for 4 h. Auditory function was evaluated by the auditory brainstem response threshold. Morphological changes of the cochleae, the expression of VEGF, and the circulation of EPCs in the peripheral blood were studied by immunohistochemistry, Western blotting analysis, scanning electron microscopy, and flow cytometry. Vascular recovery of the cochlea began after noise exposure. The change in the number of EPCs was consistent with the expression of VEGF at different time points after noise exposure. We propose that VEGF evokes specific permeable and chemotactic effects on the vascular endothelial cells. These effects can mobilize EPCs into the peripheral blood, leading the EPCs to target damaged sites and to exert a neoangiogenic effect.

Adult Plasticity in the Subcortical Auditory Pathway of the Maternal Mouse

PubMed Central

Miranda, Jason A.; Shepard, Kathryn N.; McClintock, Shannon K.; Liu, Robert C.

2014-01-01

Subcortical auditory nuclei were traditionally viewed as non-plastic in adulthood so that acoustic information could be stably conveyed to higher auditory areas. Studies in a variety of species, including humans, now suggest that prolonged acoustic training can drive long-lasting brainstem plasticity. The neurobiological mechanisms for such changes are not well understood in natural behavioral contexts due to a relative dearth of in vivo animal models in which to study this. Here, we demonstrate in a mouse model that a natural life experience with increased demands on the auditory system – motherhood – is associated with improved temporal processing in the subcortical auditory pathway. We measured the auditory brainstem response to test whether mothers and pup-naïve virgin mice differed in temporal responses to both broadband and tone stimuli, including ultrasonic frequencies found in mouse pup vocalizations. Mothers had shorter latencies for early ABR peaks, indicating plasticity in the auditory nerve and the cochlear nucleus. Shorter interpeak latency between waves IV and V also suggest plasticity in the inferior colliculus. Hormone manipulations revealed that these cannot be explained solely by estrogen levels experienced during pregnancy and parturition in mothers. In contrast, we found that pup-care experience, independent of pregnancy and parturition, contributes to shortening auditory brainstem response latencies. These results suggest that acoustic experience in the maternal context imparts plasticity on early auditory processing that lasts beyond pup weaning. In addition to establishing an animal model for exploring adult auditory brainstem plasticity in a neuroethological context, our results have broader implications for models of perceptual, behavioral and neural changes that arise during maternity, where subcortical sensorineural plasticity has not previously been considered. PMID:24992362

Adult plasticity in the subcortical auditory pathway of the maternal mouse.

PubMed

Miranda, Jason A; Shepard, Kathryn N; McClintock, Shannon K; Liu, Robert C

2014-01-01

Subcortical auditory nuclei were traditionally viewed as non-plastic in adulthood so that acoustic information could be stably conveyed to higher auditory areas. Studies in a variety of species, including humans, now suggest that prolonged acoustic training can drive long-lasting brainstem plasticity. The neurobiological mechanisms for such changes are not well understood in natural behavioral contexts due to a relative dearth of in vivo animal models in which to study this. Here, we demonstrate in a mouse model that a natural life experience with increased demands on the auditory system - motherhood - is associated with improved temporal processing in the subcortical auditory pathway. We measured the auditory brainstem response to test whether mothers and pup-naïve virgin mice differed in temporal responses to both broadband and tone stimuli, including ultrasonic frequencies found in mouse pup vocalizations. Mothers had shorter latencies for early ABR peaks, indicating plasticity in the auditory nerve and the cochlear nucleus. Shorter interpeak latency between waves IV and V also suggest plasticity in the inferior colliculus. Hormone manipulations revealed that these cannot be explained solely by estrogen levels experienced during pregnancy and parturition in mothers. In contrast, we found that pup-care experience, independent of pregnancy and parturition, contributes to shortening auditory brainstem response latencies. These results suggest that acoustic experience in the maternal context imparts plasticity on early auditory processing that lasts beyond pup weaning. In addition to establishing an animal model for exploring adult auditory brainstem plasticity in a neuroethological context, our results have broader implications for models of perceptual, behavioral and neural changes that arise during maternity, where subcortical sensorineural plasticity has not previously been considered.

Clinical, Radiologic, and Legal Significance of "Extensor Response" in Posttraumatic Coma.

PubMed

Firsching, Raimund; Woischneck, Dieter; Langejürgen, Alexander; Parreidt, Andreas; Bondar, Imre; Skalej, Martin; Röhl, Friedrich; Voellger, Benjamin

2015-11-01

The timely detection of neurologic deterioration can be critical for the survival of a neurosurgical patient following head injury. Because little reliable evidence is available on the prognostic value of the clinical sign "extensor response" in comatose posttraumatic patients, we investigated the correlation of this clinical sign with outcome and with early radiologic findings from magnetic resonance imaging (MRI). This retrospective analysis of prospectively obtained data included 157 patients who had remained in a coma for a minimum of 24 hours after traumatic brain injury. All patients received a 1.5-T MRI within 10 days (median: 2 days) of the injury. The correlations between clinical findings 12 and 24 hours after the injury-in particular, extensor response and pupillary function, MRI findings, and outcome after 1 year-were investigated. Statistical analysis included contingency tables, Fisher exact test, odds ratios (ORs) with confidence intervals (CIs), and weighted κ values. There were 48 patients with extensor response within the first 24 hours after the injury. Patients with extensor response (World Federation of Neurosurgical Societies coma grade III) statistically were significantly more likely to harbor MRI lesions in the brainstem when compared with patients in a coma who had no further deficiencies (coma grade I; p = 0.0004 by Fisher exact test, OR 10.8 with 95% CI, 2.7-42.5) and patients with unilateral loss of pupil function (coma grade II; p = 0.0187, OR 2.8 with 95% CI, 1.2-6.5). The correlation of brainstem lesions as found by MRI and outcome according to the Glasgow Outcome Scale after 1 year was also highly significant (p ≤ 0.016). The correlation of extensor response and loss of pupil function with an unfavorable outcome and with brainstem lesions revealed by MRI is highly significant. Their sudden onset may be associated with the sudden onset of brainstem dysfunction and should therefore be regarded as one of the most fundamental warning signs in the clinical monitoring of comatose patients. Georg Thieme Verlag KG Stuttgart · New York.

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

Gopishankar, N; Agarwal, Priyanka; Bisht, Raj Kishor

Purpose: To evaluate forward and inverse planning methods for acoustic neuroma cases treated in Gamma Knife Perfexion. Methods: Five patients with acoustic neuroma tumour abutting brainstem were planned twice in LGP TPS (Version 10.1) using TMR10 algorithm. First plan was entirely based on forward planning (FP) in which each shot was chosen manually. Second plan was generated using inverse planning (IP) for which planning parameters like coverage, selectivity, gradient index (GI) and beam-on time threshold were set. Number of shots in IP was automatically selected by objective function using iterative process. In both planning methods MRI MPRAGE sequence images weremore » used for tumour localization and planning. A planning dose of 12Gy at 50% isodose level was chosen. Results and Discussion: Number of shots used in FP was greater than IP and beam-on time in FP was in average 1.4 times more than IP. One advantage of FP was that the brainstem volume subjected to 6Gy dose (25% isodose) was less in FP than IP. Our results showed use of more number of shots as in FP results in GI less than or equal to 2.55 which is close to its lower limit. Dose homogeneity index (DHI) analysis of FP and IP showed average values of 0.59 and 0.67 respectively. General trend in GK for planning in acoustic neuroma cases is to use small collimator shots to avoid dose to adjacent critical structures. More number of shots and prolonged treatment time causes inconvenience to the patients. Similarly overuse of automatic shot shaping as in IP results in increased scatter dose. A compromise is required in shot selection for these cases. Conclusion: IP method could be used in acoustic neuroma cases to decrease treatment time provided the source sector openings near brainstem are shielded or adjusted appropriately to reduce brainstem dose.« less

Effects of myelin or cell body brainstem lesions on 3-channel Lissajous' trajectories of feline auditory brainstem evoked potentials.

PubMed

Pratt, H; Zaaroor, M; Bleich, N; Starr, A

1991-06-01

Auditory brainstem evoked potentials (ABEP) were recorded from 16 awake cats to obtain 3-Channel Lissajous' Trajectories (3CLTs) using three orthogonal differential electrode configurations (nasion-midline nuchal ridge, left-right mastoids, vertex-midline under the mandible). Potentials, evoked by monaural 80 dBnHL (re, human threshold) clicks, were studied before, and up to 7 weeks after inducing neuronal lesions localized to the cochlear nucleus (CN) or the superior olivary complex (SOC), or myelin lesions localized to the fibers of the trapezoid body connecting these two structures. Neuronal lesions were induced by injection of kainic acid (KA), while myelin lesions were induced by injection of L-alpha-lysophosphatidylcholine (LPC). With CN neuronal lesions the major changes in 3CLT were in the time domain of 'b', 'c' and 'd' (components P2, P3 and P4 of single-channel ABEP). With SOC neuronal lesions the major changes were in 'c' and 'd' of 3CLT (P3 and P4 of ABEP). With trapezoid body lesions the major change was in 'c' (P3 of ABEP). The results are compatible with the peripheral generation of the first ABEP components (P1a and P1b). The second component (P2) is generated by ipsilateral CN neurones and their outputs. The third component (P3) is generated primarily by ipsilateral SOC neurones and their outputs, with the ipsilateral CN providing input. The The fourth component (P4) is generated bilaterally by the SOC neurones and their outputs, receiving their inputs from ipsilateral CN. The fifth ABEP component (P5) is generated by structures central to the SOCs and their immediate outputs. Neither focal neuronal nor myelin lesions were sufficient to produce obliteration of any component, consistent with a set of generators for each of the ABEP components, consisting of both cell bodies and their output fibers, that is distributed spatially in the brainstem.

Lateralization and Binaural Interaction of Middle-Latency and Late-Brainstem Components of the Auditory Evoked Response.

PubMed

Dykstra, Andrew R; Burchard, Daniel; Starzynski, Christian; Riedel, Helmut; Rupp, Andre; Gutschalk, Alexander

2016-08-01

We used magnetoencephalography to examine lateralization and binaural interaction of the middle-latency and late-brainstem components of the auditory evoked response (the MLR and SN10, respectively). Click stimuli were presented either monaurally, or binaurally with left- or right-leading interaural time differences (ITDs). While early MLR components, including the N19 and P30, were larger for monaural stimuli presented contralaterally (by approximately 30 and 36 % in the left and right hemispheres, respectively), later components, including the N40 and P50, were larger ipsilaterally. In contrast, MLRs elicited by binaural clicks with left- or right-leading ITDs did not differ. Depending on filter settings, weak binaural interaction could be observed as early as the P13 but was clearly much larger for later components, beginning at the P30, indicating some degree of binaural linearity up to early stages of cortical processing. The SN10, an obscure late-brainstem component, was observed consistently in individuals and showed linear binaural additivity. The results indicate that while the MLR is lateralized in response to monaural stimuli-and not ITDs-this lateralization reverses from primarily contralateral to primarily ipsilateral as early as 40 ms post stimulus and is never as large as that seen with fMRI.

Optimization behavior of brainstem respiratory neurons. A cerebral neural network model.

PubMed

Poon, C S

1991-01-01

A recent model of respiratory control suggested that the steady-state respiratory responses to CO2 and exercise may be governed by an optimal control law in the brainstem respiratory neurons. It was not certain, however, whether such complex optimization behavior could be accomplished by a realistic biological neural network. To test this hypothesis, we developed a hybrid computer-neural model in which the dynamics of the lung, brain and other tissue compartments were simulated on a digital computer. Mimicking the "controller" was a human subject who pedalled on a bicycle with varying speed (analog of ventilatory output) with a view to minimize an analog signal of the total cost of breathing (chemical and mechanical) which was computed interactively and displayed on an oscilloscope. In this manner, the visuomotor cortex served as a proxy (homolog) of the brainstem respiratory neurons in the model. Results in 4 subjects showed a linear steady-state ventilatory CO2 response to arterial PCO2 during simulated CO2 inhalation and a nearly isocapnic steady-state response during simulated exercise. Thus, neural optimization is a plausible mechanism for respiratory control during exercise and can be achieved by a neural network with cognitive computational ability without the need for an exercise stimulus.

[Origin of acoustically evoked short latency negative response in guinea pigs].

PubMed

Huang, Wen-qin; Qin, Huan-hua; Nong, Dong-xiao; Tang, An-zhou; Li, Zhi-mei; Yang, Tian

2011-04-01

To establish a model of acoustically evoked short latency negative response (ASNR) in guinea pigs, a model of profound hearing loss with normal saccular functions, and verify the correlation between ASNR and vestibular evoked myogenic potential (VEMP). Thirty-two healthy guinea pigs were employed in the experiment, which were randomly divided into control group (16 subjects) and deafened group (16 subjects). Each animal experienced auditory and vestibular tests including auditory brainstem response (ABR), VEMP and caloric test. A quick treatment was employed for deafened group consisting of a subcutaneous injection of kanamycin at a dose of 400 mg/kg followed by a jugular vein injection of ethacrynic acid at a dose of 40 mg/kg one hour later. The animals were received ABR, VEMP and caloric test 7 - 10 days following the drug administration. The deafened group was further divided into ASNR group and non-ASNR group, based on the presence of ASNR. In deafened group, five subjects died postoperatively, 11 subjects (22 ears) provided full data, ASNR was elicited in eight ears (36.4%), the threshold was 120 - 130 dB SPL with mean of (124.4 ± 4.96) dB SPL. Its latency range was 1.75 - 2.60 ms with mean of (2.15 ± 0.27) ms. The mean latency of threshold was (2.34 ± 0.18) ms. All eight ASNR ears presented with VEMP. The VEMP threshold, positive and negative potential latencies proved no statistical difference (P > 0.05) between ASNR group and control group. Significant difference was detected between the VEMP presence of ASNR group and non-ASNR group (P = 0.002). There was no statistically significant correlation between VEMP and caloric test neither between ASNR and caloric test in deafened group. This study evoked ASNR in an ototoxicity guinea pig model which has profound hearing loss with normal saccular functions. The presence of ASNR correlated with VEMP, however, not correlated with caloric test, suggesting that ASNR and VEMP are both originated from the saccule.

The Physiological Bases of Hidden Noise-Induced Hearing Loss: Protocol for a Functional Neuroimaging Study

PubMed Central

Hall, Deborah A; Guest, Hannah; Prendergast, Garreth; Plack, Christopher J; Francis, Susan T

2018-01-01

Background Rodent studies indicate that noise exposure can cause permanent damage to synapses between inner hair cells and high-threshold auditory nerve fibers, without permanently altering threshold sensitivity. These demonstrations of what is commonly known as hidden hearing loss have been confirmed in several rodent species, but the implications for human hearing are unclear. Objective Our Medical Research Council–funded program aims to address this unanswered question, by investigating functional consequences of the damage to the human peripheral and central auditory nervous system that results from cumulative lifetime noise exposure. Behavioral and neuroimaging techniques are being used in a series of parallel studies aimed at detecting hidden hearing loss in humans. The planned neuroimaging study aims to (1) identify central auditory biomarkers associated with hidden hearing loss; (2) investigate whether there are any additive contributions from tinnitus or diminished sound tolerance, which are often comorbid with hearing problems; and (3) explore the relation between subcortical functional magnetic resonance imaging (fMRI) measures and the auditory brainstem response (ABR). Methods Individuals aged 25 to 40 years with pure tone hearing thresholds ≤20 dB hearing level over the range 500 Hz to 8 kHz and no contraindications for MRI or signs of ear disease will be recruited into the study. Lifetime noise exposure will be estimated using an in-depth structured interview. Auditory responses throughout the central auditory system will be recorded using ABR and fMRI. Analyses will focus predominantly on correlations between lifetime noise exposure and auditory response characteristics. Results This paper reports the study protocol. The funding was awarded in July 2013. Enrollment for the study described in this protocol commenced in February 2017 and was completed in December 2017. Results are expected in 2018. Conclusions This challenging and comprehensive study will have the potential to impact diagnostic procedures for hidden hearing loss, enabling early identification of noise-induced auditory damage via the detection of changes in central auditory processing. Consequently, this will generate the opportunity to give personalized advice regarding provision of ear defense and monitoring of further damage, thus reducing the incidence of noise-induced hearing loss. PMID:29523503

On the Relevance of Natural Stimuli for the Study of Brainstem Correlates: The Example of Consonance Perception

PubMed Central

Cousineau, Marion; Bidelman, Gavin M.; Peretz, Isabelle; Lehmann, Alexandre

2015-01-01

Some combinations of musical tones sound pleasing to Western listeners, and are termed consonant, while others sound discordant, and are termed dissonant. The perceptual phenomenon of consonance has been traced to the acoustic property of harmonicity. It has been repeatedly shown that neural correlates of consonance can be found as early as the auditory brainstem as reflected in the harmonicity of the scalp-recorded frequency-following response (FFR). “Neural Pitch Salience” (NPS) measured from FFRs—essentially a time-domain equivalent of the classic pattern recognition models of pitch—has been found to correlate with behavioral judgments of consonance for synthetic stimuli. Following the idea that the auditory system has evolved to process behaviorally relevant natural sounds, and in order to test the generalizability of this finding made with synthetic tones, we recorded FFRs for consonant and dissonant intervals composed of synthetic and natural stimuli. We found that NPS correlated with behavioral judgments of consonance and dissonance for synthetic but not for naturalistic sounds. These results suggest that while some form of harmonicity can be computed from the auditory brainstem response, the general percept of consonance and dissonance is not captured by this measure. It might either be represented in the brainstem in a different code (such as place code) or arise at higher levels of the auditory pathway. Our findings further illustrate the importance of using natural sounds, as a complementary tool to fully-controlled synthetic sounds, when probing auditory perception. PMID:26720000

Stress-induced activation of the brainstem Bcl-xL gene expression in rats treated with fluoxetine: correlations with serotonin metabolism and depressive-like behavior.

PubMed

Shishkina, Galina T; Kalinina, Tatyana S; Berezova, Inna V; Dygalo, Nikolay N

2012-01-01

Mechanisms underlying stress-induced depression and antidepressant drug action were shown to involve alterations in serotonergic (5-HT) neurotransmission and expression of genes coding for proteins associated with neurotrophic signaling pathways and cell-survival in the hippocampus and cortex. Expression of these genes in the brainstem containing 5-HT neurons may also be related to vulnerability or resilience to stress-related psychopathology. Here we investigated 5-HT markers and expression of genes for Brain-Derived Neurotrophic Factor (BDNF) and apoptotic proteins in the brainstem in relation to swim stress-induced behavioral despair. We found that anti-apoptotic Bcl-xL gene is sensitive to stress during the course of fluoxetine administration. Responsiveness of this gene to stress appeared concomitantly with an antidepressant-like effect of fluoxetine in the forced swim test. Bcl-xL transcript levels showed negative correlations with duration of immobility in the test and 5-HT turnover in the brainstem. In contrast, BDNF and pro-apoptotic protein Bax mRNA levels were unchanged by either fluoxetine or stress, suggesting specificity of Bcl-xL gene responses to these treatments. We also found that the levels of mRNAs for tryptophan hydroxylase-2 (TPH2) and 5-HT transporter (5-HTT) were significantly down-regulated following prolonged treatment with fluoxetine, but were not affected by stress. Unlike TPH2 and 5-HTT, 5-HT1A receptor mRNA levels were not altered by fluoxetine but significantly increased in response to swim stress. These data show that long-term fluoxetine treatment leads to changes in 5-HT and Bcl-xL responses to stress associated with antidepressant-like effects of the drug. This article is part of a Special Issue entitled 'Anxiety and Depression'. Copyright © 2011 Elsevier Ltd. All rights reserved.

Computational modeling of the human auditory periphery: Auditory-nerve responses, evoked potentials and hearing loss.

PubMed

Verhulst, Sarah; Altoè, Alessandro; Vasilkov, Viacheslav

2018-03-01

Models of the human auditory periphery range from very basic functional descriptions of auditory filtering to detailed computational models of cochlear mechanics, inner-hair cell (IHC), auditory-nerve (AN) and brainstem signal processing. It is challenging to include detailed physiological descriptions of cellular components into human auditory models because single-cell data stems from invasive animal recordings while human reference data only exists in the form of population responses (e.g., otoacoustic emissions, auditory evoked potentials). To embed physiological models within a comprehensive human auditory periphery framework, it is important to capitalize on the success of basic functional models of hearing and render their descriptions more biophysical where possible. At the same time, comprehensive models should capture a variety of key auditory features, rather than fitting their parameters to a single reference dataset. In this study, we review and improve existing models of the IHC-AN complex by updating their equations and expressing their fitting parameters into biophysical quantities. The quality of the model framework for human auditory processing is evaluated using recorded auditory brainstem response (ABR) and envelope-following response (EFR) reference data from normal and hearing-impaired listeners. We present a model with 12 fitting parameters from the cochlea to the brainstem that can be rendered hearing impaired to simulate how cochlear gain loss and synaptopathy affect human population responses. The model description forms a compromise between capturing well-described single-unit IHC and AN properties and human population response features. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Exposure to a high-fat high-sugar diet causes strong up-regulation of proopiomelanocortin and differentially affects dopamine D1 and D2 receptor gene expression in the brainstem of rats.

PubMed

Alsiö, Johan; Rask-Andersen, Mathias; Chavan, Rohit A; Olszewski, Pawel K; Levine, Allen S; Fredriksson, Robert; Schiöth, Helgi B

2014-01-24

A strong link between obesity and dopamine (DA) has been established by studies associating body weight status to variants of genes related to DA signalling. Human and animal studies investigating this relationship have so far focused mainly on the role of DA within the mesolimbic pathway. The aim of this study was to investigate potential DA receptor dysregulation in the brainstem, where these receptors play a potential role in meal termination, during high-fat high-sugar diet (HFHS) exposure. Expression of other key genes, including proopiomelanocortin (POMC), was also analyzed. We randomized rats into three groups; ad libitum access to HFHS (n=24), restricted HFHS access (n=10), or controls (chow-fed, n=10). After 5 weeks, brainstem gene expression was investigated by qRT-PCR. We observed an increase in POMC expression in ad libitum HFHS-fed rats compared to chow-fed controls (p<0.05). Further, expression of DA D2 receptor mRNA was down-regulated in the brainstem of the HFHS ad libitum-fed rats (p<0.05), whereas expression of the DA D1 receptor was upregulated (p<0.05) in these animals compared to chow-fed rats. In control experiments, we observed no effect relative to chow-fed controls on DA-receptor or POMC gene expression in the hypothalamus of HFHS diet-exposed rats, or in the brainstem of acutely food deprived rats. The present findings suggest brainstem POMC to be responsive to palatable foods, and that DA dysregulation after access to energy-dense diets occurs not only in striatal regions, but also in the brainstem, which could be relevant for overeating and for the development and maintenance of obesity. Copyright © 2013. Published by Elsevier Ireland Ltd.

Administration of IL-1beta to the 4th ventricle causes anorexia that is blocked by agouti-related peptide and that coincides with activation of tyrosine-hydroxylase neurons in the nucleus of the solitary tract.

PubMed

DeBoer, Mark D; Scarlett, Jarrad M; Levasseur, Peter R; Grant, Wilmon F; Marks, Daniel L

2009-02-01

Inflammation-associated cachexia is associated with multiple chronic diseases and involves activation of appetite regulating centers in the arcuate nucleus of the hypothalamus (ARH). The nucleus of the solitary tract (NTS) in the brainstem has also been implicated as an important nucleus involved in appetite regulation. We set out to determine whether the NTS may be involved in inflammation-associated anorexia by injecting IL-1 beta into the 4th ventricle and assessing food intake and NTS neuronal activation. Injection of IL-1 beta produced a decrease in food intake at 3 and 12h after injection which was ameliorated at the 12h time point by a sub-threshold dose of agouti-related peptide (AgRP). Investigation into neuron types in the NTS revealed that IL-1 beta injection was associated with an increase in c-Fos activity in NTS neurons expressing tyrosine hydroxylase (TH). Additionally, injection of IL-1 beta into the 4th ventricle did not produce c-Fos activation of neurons expressing pro-opiomelanocortin (POMC) in the ARH, cells known to be involved in producing anorexia in response to systemic inflammation. Double-label in situ hybridization revealed that TH neurons did not express IL-1 receptor I (IL1-RI) transcript, demonstrating that c-Fos activation of TH neurons in this setting was not via direct stimulation of IL-1 beta on TH neurons themselves. We conclude that IL-1 beta injection into the 4th ventricle produces anorexia and is accompanied by an increase in activation in TH neurons in the NTS. This provides evidence that the brainstem may be an important mediator of anorexia in the setting of inflammation.

Nanofibrous scaffolds for the guidance of stem cell-derived neurons for auditory nerve regeneration.

PubMed

Hackelberg, Sandra; Tuck, Samuel J; He, Long; Rastogi, Arjun; White, Christina; Liu, Liqian; Prieskorn, Diane M; Miller, Ryan J; Chan, Che; Loomis, Benjamin R; Corey, Joseph M; Miller, Josef M; Duncan, R Keith

2017-01-01

Impairment of spiral ganglion neurons (SGNs) of the auditory nerve is a major cause for hearing loss occurring independently or in addition to sensory hair cell damage. Unfortunately, mammalian SGNs lack the potential for autonomous regeneration. Stem cell based therapy is a promising approach for auditory nerve regeneration, but proper integration of exogenous cells into the auditory circuit remains a fundamental challenge. Here, we present novel nanofibrous scaffolds designed to guide the integration of human stem cell-derived neurons in the internal auditory meatus (IAM), the foramen allowing passage of the spiral ganglion to the auditory brainstem. Human embryonic stem cells (hESC) were differentiated into neural precursor cells (NPCs) and seeded onto aligned nanofiber mats. The NPCs terminally differentiated into glutamatergic neurons with high efficiency, and neurite projections aligned with nanofibers in vitro. Scaffolds were assembled by seeding GFP-labeled NPCs on nanofibers integrated in a polymer sheath. Biocompatibility and functionality of the NPC-seeded scaffolds were evaluated in vivo in deafened guinea pigs (Cavia porcellus). To this end, we established an ouabain-based deafening procedure that depleted an average 72% of SGNs from apex to base of the cochleae and caused profound hearing loss. Further, we developed a surgical procedure to implant seeded scaffolds directly into the guinea pig IAM. No evidence of an inflammatory response was observed, but post-surgery tissue repair appeared to be facilitated by infiltrating Schwann cells. While NPC survival was found to be poor, both subjects implanted with NPC-seeded and cell-free control scaffolds showed partial recovery of electrically-evoked auditory brainstem thresholds. Thus, while future studies must address cell survival, nanofibrous scaffolds pose a promising strategy for auditory nerve regeneration.

Behavioral State Modulates the Activity of Brainstem Sensorimotor Neurons

PubMed Central

McArthur, Kimberly L.

2011-01-01

Sensorimotor processing must be modulated according to the animal's behavioral state. A previous study demonstrated that motion responses were strongly state dependent in birds. Vestibular eye and head responses were significantly larger and more compensatory during simulated flight, and a flight-specific vestibular tail response was also characterized. In the current study, we investigated the neural substrates for these state-dependent vestibular behaviors by recording extracellularly from neurons in the vestibular nuclear complex and comparing their spontaneous activity and sensory responses during default and simulated flight states. We show that motion-sensitive neurons in the lateral vestibular nucleus are state dependent. Some neurons increased their spontaneous firing rates during flight, though their increased excitability was not reflected in higher sensory gains. However, other neurons exhibited state-dependent gating of sensory inputs, responding to rotational stimuli only during flight. These results demonstrate that vestibular processing in the brainstem is state dependent and lay the foundation for future studies to investigate the synaptic mechanisms responsible for these modifications. PMID:22090497

Electrophysiologic Study of a Method of Euthanasia Using Intrathecal Lidocaine Hydrochloride Administered during Intravenous Anesthesia in Horses.

PubMed

Aleman, M; Davis, E; Williams, D C; Madigan, J E; Smith, F; Guedes, A

2015-01-01

An intravenous (IV) overdose of pentobarbital sodium is the most commonly used method of euthanasia in veterinary medicine. However, this compound is not available in many countries or rural areas resulting in usage of alternative methods such as intrathecal lidocaine administration after IV anesthesia. Its safety and efficacy as a method of euthanasia have not been investigated in the horse. To investigate changes in mean arterial blood pressure and electrical activity of the cerebral cortex, brainstem, and heart during intrathecal administration of lidocaine. Our hypothesis was that intrathecal lidocaine affects the cerebral cortex and brainstem before affecting cardiovascular function. Eleven horses requiring euthanasia for medical reasons. Prospective observational study. Horses were anesthetized with xylazine, midazolam, and ketamine; and instrumented for recording of electroencephalogram (EEG), electrooculogram (EOG), brainstem auditory evoked response (BAER), and electrocardiogram (ECG). Physical and neurological (brainstem reflexes) variables were monitored. Mean arterial blood pressure was recorded throughout the study. Loss of cerebro-cortical electrical activity occurred up to 226 seconds after the end of the infusion of lidocaine solution. Cessation of brainstem function as evidenced by a lack of brainstem reflexes and disappearance of BAER occurred subsequently. Undetectable heart sounds, nonpalpable arterial pulse, and extremely low mean arterial blood pressure supported cardiac death; a recordable ECG was the last variable to disappear after the infusion (300-1,279 seconds). Intrathecal administration of lidocaine is an effective alternative method of euthanasia in anesthetized horses, during which brain death occurs before cardiac death. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of American College of Veterinary Internal Medicine.

Visual recognition memory and auditory brainstem response in infant rhesus monkeys exposed perinatally to environmental tobacco smoke.

PubMed

Golub, Mari S; Slotkin, Theodore A; Tarantal, Alice F; Pinkerton, Kent E

2007-06-02

The impact of perinatal exposure to environmental tobacco smoke (ETS) on cognitive development is controversial. We exposed rhesus monkeys to ETS or filtered air (5 animals per group) beginning in utero on day 50 of pregnancy and continuing throughout postnatal testing. In infancy, we evaluated both groups for visual recognition memory and auditory function (auditory brainstem response). The ETS group showed significantly less novelty preference in the visual recognition task whereas no effects on auditory function were detected. These preliminary results support the view that perinatal ETS exposure has adverse effects on cognitive function and indicate further that rhesus monkeys may provide a valuable nonhuman primate model for investigating this link.

A brief review of the clinical anatomy of the vestibular-ocular connections-how much do we know?

PubMed

Bronstein, A M; Patel, M; Arshad, Q

2015-02-01

The basic connectivity from the vestibular labyrinth to the eye muscles (vestibular ocular reflex, VOR) has been elucidated in the past decade, and we summarise this in graphic format. We also review the concept of 'velocity storage', a brainstem integrator that prolongs vestibular responses. Finally, we present new discoveries of how complex visual stimuli, such as binocular rivalry, influence VOR processing. In contrast to the basic brainstem circuits, cortical vestibular circuits are far from being understood, but parietal-vestibular nuclei projections are likely to be involved.

Gestational flu exposure induces changes in neurochemicals, affiliative hormones and brainstem inflammation, in addition to autism-like behaviors in mice.

PubMed

Miller, V M; Zhu, Y; Bucher, C; McGinnis, W; Ryan, L K; Siegel, A; Zalcman, S

2013-10-01

The prevalence of neurodevelopmental disorders such as autism is increasing, however the etiology of these disorders is unclear and thought to involve a combination of genetic, environmental and immune factors. A recent epidemiological study found that gestational viral exposure during the first trimester increases risk of autism in offspring by twofold. In mice gestational viral exposures alter behavior of offspring, but the biological mechanisms which underpin these behavioral changes are unclear. We hypothesized that gestational viral exposure induces changes in affiliative hormones, brainstem autonomic nuclei and neurotransmitters which are associated with behavioral alterations in offspring. To address this hypothesis, we exposed pregnant mice to influenza A virus (H3N2) on gestational day 9 and determined behavioral, hormonal and brainstem changes in male and female offspring. We found that gestational flu exposure induced dose-dependent alterations in social and aggressive behaviors (p≤0.05) in male and female offspring and increases in locomotor behaviors particularly in male offspring (p≤0.05). We found that flu exposure was also associated with reductions in oxytocin and serotonin (p≤0.05) levels in male and female offspring and sex-specific changes in dopamine metabolism. In addition we found changes in catecholaminergic and microglia density in brainstem tissues of male flu exposed offspring only (p≤0.05). This study demonstrates that gestational viral exposure induces behavioral changes in mice, which are associated with alterations in affiliative hormones. In addition we found sex-specific changes in locomotor behavior, which may be associated with sex-specific alterations in dopamine metabolism and brainstem inflammation. Further investigations into maternal immune responses are necessary to unravel the molecular mechanisms which underpin abnormal hormonal, immune and behavioral responses in offspring after gestational viral exposure. Copyright © 2013 Elsevier Inc. All rights reserved.

Effect of Brain Stem and Dorsal Vagus Complex Dosimetry on Nausea and Vomiting in Head and Neck Intensity-Modulated Radiation Therapy

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

Ciura, Katherine; McBurney, Michelle; Nguyen, Baongoc

Intensity-modulated radiation therapy (IMRT) is becoming the treatment of choice for many head and neck cancer patients. IMRT reduces some toxicities by reducing radiation dose to uninvolved normal tissue near tumor targets; however, other tissues not irradiated using previous 3D techniques may receive clinically significant doses, causing undesirable side effects including nausea and vomiting (NV). Irradiation of the brainstem, and more specifically, the area postrema and dorsal vagal complex (DVC), has been linked to NV. We previously reported preliminary hypothesis-generating dose effects associated with NV in IMRT patients. The goal of this study is to relate brainstem dose to NVmore » symptoms. We retrospectively studied 100 consecutive patients that were treated for oropharyngeal cancer with IMRT. We contoured the brainstem, area postrema, and DVC with the assistance of an expert diagnostic neuroradiologist. We correlated dosimetry for the 3 areas contoured with weekly NV rates during IMRT. NV rates were significantly higher for patients who received concurrent chemotherapy. Post hoc analysis demonstrated that chemoradiation cases exhibited a trend towards the same dose-response relationship with both brainstem mean dose (p = 0.0025) and area postrema mean dose (p = 0.004); however, both failed to meet statistical significance at the p {<=} 0.002 level. Duration of toxicity was also greater for chemoradiation patients, who averaged 3.3 weeks with reported Common Terminology Criteria for Adverse Events (CTC-AE), compared with an average of 2 weeks for definitive RT patients (p = 0.002). For definitive RT cases, no dose-response trend could be ascertained. The mean brainstem dose emerged as a key parameter of interest; however, no one dose parameter (mean/median/EUD) best correlated with NV. This study does not address extraneous factors that would affect NV incidence, including the use of antiemetics, nor chemotherapy dose schedule specifics before and during RT. A prospective study will be required to depict exactly how IMRT dose affects NV.« less

Therapeutic effect of adeno-associated virus (AAV)-mediated ADNF-9 expression on cochlea of kanamycin-deafened guinea pigs.

PubMed

Zheng, Guoxi; Zhu, Zhu; Zhu, Kang; Wei, Junrong; Jing, Yang; Duan, Maoli

2013-10-01

rAAV-NT4-ADNF-9 could ameliorate the damage to auditory function and repair previous impairment of cochlear hair cell loss induced by kanamycin. To investigate the therapeutic effect of ADNF-9 on cochlear hair cells using the recombinant adeno-associated virus (AAV) carrying fusion gene NT4-ADNF-9 and the kanamycin-deafened guinea pig model. Forty white guinea pigs with normal auricle reflex and normal auditory brainstem responses (ABRs) were randomly divided into four groups. Kanamycin was administered to the animals in groups A, B, and C to establish the deafened guinea pig model. rAAV-NT4-ADNF-9, vector only, and artificial perilymph were then delivered to the cochlear tissue of animals in groups A, B, and C, respectively, through the round window membrane. Animals in group D did not receive any treatment and acted as normal controls. The hearing thresholds on the surgery side were recorded before and after the transfection treatment. Fourteen days after treatment, cochleae were removed for paraffin slide preparation and cochlear surface preparation. A phase contrast microscope was used to observe the protective effect of ADNF-9 on hair cells. Significant reduction of the ABR threshold was observed after rAAV-NT4-ADNF-9 treatment (p < 0.05). After 14 days of treatment, the ABR threshold was also significantly different between the rAAV-NT4-ADNF-9-infected group and the non-infected group. Moreover, phase contrast microscopy showed significantly less hair cell damage or hair cell loss in the group treated with rAAV-NT4-ADNF-9 than in the groups treated with vector only or artificial perilymph (p < 0.05).

Could edaravone prevent gentamicin ototoxicity? An experimental study.

PubMed

Turan, M; Ciğer, E; Arslanoğlu, S; Börekci, H; Önal, K

2017-02-01

Clinical application of gentamicin may cause nephrotoxicity and ototoxicity. Our study is the first study to investigate the protective effects of edaravone against the gentamicin-induced ototoxicity. We investigated the protective effect of intraperitoneal (i.p.) edaravone application against gentamicin-induced ototoxicity in guinea pigs. Fourteen guinea pigs were divided into two equal groups consisting of a control group and a study group. One-hundred sixty milligrams per kilogram subcutaneous gentamicin and 0.3 mL i.p. saline were applied simultaneously once daily to seven guinea pigs in the control group (group 1). One-hundred sixty milligrams per kilogram gentamicin was applied subcutaneously and 3 mg/kg edaravone was applied intraperitoneally once daily for 7 days simultaneously to seven guinea pigs in the study group (group 2). Following the drug application, auditory brainstem response measurements were performed for the left ear on the 3rd and 7th days. Hearing threshold values of the group 1 and group 2 measured in the 3rd day of the study were detected as 57.14 ± 4.88 and 82.86 ± 7.56, respectively. This difference was statistically significant ( p < 0.05). Hearing threshold values of the group 1 and group 2 measured in the 7th day of the study were detected as 87.14 ± 4.88 and 62.86 ± 4.88, respectively. This difference was statistically significant ( p < 0.05). A statistically significant difference between the average threshold values of edaravone-administered group 2 and that of group 1 without edaravone was found. These differences show that systemic edaravone administration could diminish ototoxic effects of gentamicin and the severity of the hearing loss.

A new oral otoprotective agent. Part 1: Electrophysiology data from protection against noise-induced hearing loss

PubMed Central

Cascella, Vincenza; Giordano, Pietro; Hatzopoulos, Stavros; Petruccelli, Joseph; Prosser, Silvano; Simoni, Edi; Astolfi, Laura; Fetoni, Annarita Rita; Skarżyński, Henryk; Martini, Alessandro

2012-01-01

Summary Background Data from animal studies show that antioxidants can compensate against noise-induced stress and sensory hair cell death. The aim of this study was to evaluate the otoprotection efficacy of various versions of orally administered Acuval 400® against noise damage in a rat animal model. Material/Methods Fifty-five Sprague Dawley rats were divided into 4 groups: A) noise-exposed animals; B) animals exposed to noise and treated with the Acuval; C) animals exposed to noise and treated with a combination of Coenzyme Q10 and Acuval; D) animals treated only with Acuval and Coenzyme Q10 and with no exposure to noise. All solutions were administered orally 5 times: 24 and 2 hrs prior to noise exposure, and then daily for 3 days. The auditory function was assessed by measuring auditory brainstem responses (ABR) in the range from 2 to 32 kHz at times =1, 7, 14 and 21 days after noise exposure. Results At low frequencies (click and 4 kHz) animals from both A and B groups showed significant threshold shifts in the majority of the tested frequencies and tested times. For the same frequencies, animals from group C presented threshold levels similar to those from group D. At frequencies ≥8 kHz the protective performance of the 2 Acuval groups is more clearly distinguished from the noise group A. At 32 kHz the 2 Acuval groups perform equally well in terms of otoprotection. Animals in Group D did not show any significant differences in the hearing threshold during the experiment. Conclusions The data of this study suggest that a solution containing Coenzyme Q10 and Acuval 400®, administered orally, protects from noise-induced hearing loss. PMID:22207104

A new oral otoprotective agent. Part 1: Electrophysiology data from protection against noise-induced hearing loss.

PubMed

Cascella, Vincenza; Giordano, Pietro; Hatzopoulos, Stavros; Petruccelli, Joseph; Prosser, Silvano; Simoni, Edi; Astolfi, Laura; Fetoni, Anna Rita; Skarżyński, Henryk; Martini, Alessandro

2012-01-01

Data from animal studies show that antioxidants can compensate against noise-induced stress and sensory hair cell death. The aim of this study was to evaluate the otoprotection efficacy of various versions of orally administered Acuval 400 against noise damage in a rat animal model. Fifty-five Sprague Dawley rats were divided into 4 groups: A) noise-exposed animals; B) animals exposed to noise and treated with the Acuval; C) animals exposed to noise and treated with a combination of Coenzyme Q10 and Acuval; D) animals treated only with Acuval and Coenzyme Q10 and with no exposure to noise. All solutions were administered orally 5 times: 24 and 2 hrs prior to noise exposure, and then daily for 3 days. The auditory function was assessed by measuring auditory brainstem responses (ABR) in the range from 2 to 32 kHz at times =1, 7, 14 and 21 days after noise exposure. At low frequencies (click and 4 kHz) animals from both A and B groups showed significant threshold shifts in the majority of the tested frequencies and tested times. For the same frequencies, animals from group C presented threshold levels similar to those from group D. At frequencies ≥ 8 kHz the protective performance of the 2 Acuval groups is more clearly distinguished from the noise group A. At 32 kHz the 2 Acuval groups perform equally well in terms of otoprotection. Animals in Group D did not show any significant differences in the hearing threshold during the experiment. The data of this study suggest that a solution containing Coenzyme Q10 and Acuval 400, administered orally, protects from noise-induced hearing loss.

Increased anesthesia time using 2,2,2-tribromoethanol-chloral hydrate with low impact on mouse psychoacoustics.

PubMed

Maheras, Kathleen J; Gow, Alexander

2013-09-30

To examine psychoacoustics in mice, we have used 2,2,2-tribromoethanol anesthesia in multiple studies. We find this drug is fast-acting and yields consistent results, providing 25-30 min of anesthesia. Our recent studies in binaural hearing prompted development of a regimen to anesthesia time to 1h. We tested a novel cocktail using 2,2,2-tribromoethanol coupled with low dose chloral hydrate to extend the effective anesthesia time. We have established an intraperitoneal dosing regimen for 2,2,2-tribromoethanol-chloral hydrate anesthesia. To measure efficacy of the drug cocktail, we measured auditory brainstem responses (ABRs) at 10 min intervals to determine the effects on hearing thresholds and wave amplitudes and latencies. This novel drug combination increases effective anesthesia to 1h. ABR Wave I amplitudes, but not latencies, are marginally suppressed. Additionally, amplitudes of the centrally derived Waves III and V show significant inter-animal variability that is independent of stimulus intensity. These data argue against the systematic suppression of ABRs by the drug cocktail. Using 2,2,2-tribromoethanol-chloral hydrate combination in psychoacoustic studies has several advantages over other drug cocktails, the most important being preservation of latencies from centrally- and peripherally-derived ABR waves. In addition, hearing thresholds are unchanged and wave amplitudes are not systematically suppressed, although they exhibit greater variability. We demonstrate that 375 mg/kg 2,2,2-tribromoethanol followed after 5 min by 200mg/kg chloral hydrate provides an anesthesia time of 60 min, has negligible effects on ABR wave latencies and thresholds and non-systematic effects on amplitudes. Copyright © 2013 Elsevier B.V. All rights reserved.

Increased Anesthesia Time Using 2,2,2-tribromoethanol-Chloral Hydrate With Low Impact On Mouse Psychoacoustics

PubMed Central

Maheras, Kathleen J.; Gow, Alexander

2013-01-01

Background To examine psychoacoustics in mice, we have used 2,2,2-tribromoethanol anesthesia in multiple studies. We find this drug is fast-acting and yields consistent results, providing 30 – 40 min of anesthesia. Our recent studies in binaural hearing prompted development of a regimen to anesthesia time to one hour. We tested a novel cocktail using 2,2,2-tribromoethanol coupled with low dose chloral hydrate to extend the effective anesthesia time. New Method We have established an intraperitoneal dosing regimen for 2,2,2-tribromoethanol-chloral hydrate anesthesia. To measure efficacy of the drug cocktail, we measured auditory brainstem responses (ABRs) at 10 min intervals to determine the effects on hearing thresholds and wave amplitudes and latencies. Results This novel drug combination increases effective anesthesia to one hour. ABR Wave I amplitudes, but not latencies, are marginally suppressed. Additionally, amplitudes of the centrally-derived Waves III and V show significant inter-animal variability that is independent of stimulus intensity. These data argue against the systematic suppression of ABRs by the drug cocktail. Comparison with Existing Methods Using 2,2,2-tribromoethanol-chloral hydrate combination in psychoacoustic studies has several advantages over other drug cocktails, the most important being preservation of latencies from centrally- and peripherally-derived ABR waves. In addition, hearing thresholds are unchanged and wave amplitudes are not systematically suppressed, although they exhibit greater variability. Conclusions We demonstrate that 375 mg/kg 2,2,2-tribromoethanol followed after five min by 200 mg/kg chloral hydrate provides an anesthesia time of 60 min, has negligible effects on ABR wave latencies and thresholds and non-systematic effects on amplitudes. PMID:23856212

Posterior reversible encephalopathy as the first manifestation of Bickerstaff's brainstem encephalitis.

PubMed

Chen, Pei-Ru; Chen, Shih-Pin

2016-11-08

Posterior reversible encephalopathy syndrome (PRES) has been associated with Guillain-Barre syndrome in rare cases. Here we report a patient in whom PRES was the presenting manifestation of Bickerstaff's brainstem encephalitis. A 75-year-old woman presented with acute onset of hypertension, headache, blurred vision, and left eyelid drooping. Magnetic resonance imaging of the brain showed characteristic PRES lesions involving the parietal and occipital lobes bilaterally. On the 6th day after symptom onset, the patient developed complete ptosis and external ophthalmoplegia of both eyes, progressive ataxia, and bilateral lower limb weakness. Cerebrospinal fluid analyses revealed albuminocytological dissociation (protein: 66.6 mg/dL, WBC: 0/μl), and nerve conduction studies showed demyelinating sensorimotor polyneuropathy. The patient developed somnolence and a left extensor plantar response on the 8th day. A diagnosis of Bickerstaff's brainstem encephalitis was made. Treatment with plasmapheresis led to a rapid improvement of clinical symptoms. To date, only five similar cases have been reported, but this is the only case in which PRES developed prior to treatment. PRES can be a comorbid condition with Bickerstaff's brainstem encephalitis, either preceding or following treatment; caution should be used in patients with either syndrome who exhibit atypical presentations.

The Brainstem and Serotonin in the Sudden Infant Death Syndrome

PubMed Central

Kinney, Hannah C.; Richerson, George B.; Dymecki, Susan M.; Darnall, Robert A.; Nattie, Eugene E.

2012-01-01

The sudden infant death syndrome (SIDS) is the sudden death of an infant under one year of age that is typically associated with sleep and that remains unexplained after a complete autopsy and death scene investigation. A leading hypothesis about its pathogenesis is that many cases result from defects in brainstem-mediated protective responses to homeostatic stressors occurring during sleep in a critical developmental period. Here we review the evidence for the brainstem hypothesis in SIDS with a focus upon abnormalities related to the neurotransmitter serotonin in the medulla oblongata, as these are the most robust pathologic findings to date. In this context, we synthesize the human autopsy data with genetic, whole-animal, and cellular data concerning the function and development of the medullary serotonergic system. These emerging data suggest an important underlying mechanism in SIDS that may help lead to identification of infants at risk and specific interventions to prevent death. PMID:19400695

Speech-evoked auditory brainstem responses in children with hearing loss.

PubMed

Koravand, Amineh; Al Osman, Rida; Rivest, Véronique; Poulin, Catherine

2017-08-01

The main objective of the present study was to investigate subcortical auditory processing in children with sensorineural hearing loss. Auditory Brainstem Responses (ABRs) were recorded using click and speech/da/stimuli. Twenty-five children, aged 6-14 years old, participated in the study: 13 with normal hearing acuity and 12 with sensorineural hearing loss. No significant differences were observed for the click-evoked ABRs between normal hearing and hearing-impaired groups. For the speech-evoked ABRs, no significant differences were found for the latencies of the following responses between the two groups: onset (V and A), transition (C), one of the steady-state wave (F), and offset (O). However, the latency of the steady-state waves (D and E) was significantly longer for the hearing-impaired compared to the normal hearing group. Furthermore, the amplitude of the offset wave O and of the envelope frequency response (EFR) of the speech-evoked ABRs was significantly larger for the hearing-impaired compared to the normal hearing group. Results obtained from the speech-evoked ABRs suggest that children with a mild to moderately-severe sensorineural hearing loss have a specific pattern of subcortical auditory processing. Our results show differences for the speech-evoked ABRs in normal hearing children compared to hearing-impaired children. These results add to the body of the literature on how children with hearing loss process speech at the brainstem level. Copyright © 2017 Elsevier B.V. All rights reserved.

Hierarchical neurocomputations underlying concurrent sound segregation: connecting periphery to percept.

PubMed

Bidelman, Gavin M; Alain, Claude

2015-02-01

Natural soundscapes often contain multiple sound sources at any given time. Numerous studies have reported that in human observers, the perception and identification of concurrent sounds is paralleled by specific changes in cortical event-related potentials (ERPs). Although these studies provide a window into the cerebral mechanisms governing sound segregation, little is known about the subcortical neural architecture and hierarchy of neurocomputations that lead to this robust perceptual process. Using computational modeling, scalp-recorded brainstem/cortical ERPs, and human psychophysics, we demonstrate that a primary cue for sound segregation, i.e., harmonicity, is encoded at the auditory nerve level within tens of milliseconds after the onset of sound and is maintained, largely untransformed, in phase-locked activity of the rostral brainstem. As then indexed by auditory cortical responses, (in)harmonicity is coded in the signature and magnitude of the cortical object-related negativity (ORN) response (150-200 ms). The salience of the resulting percept is then captured in a discrete, categorical-like coding scheme by a late negativity response (N5; ~500 ms latency), just prior to the elicitation of a behavioral judgment. Subcortical activity correlated with cortical evoked responses such that weaker phase-locked brainstem responses (lower neural harmonicity) generated larger ORN amplitude, reflecting the cortical registration of multiple sound objects. Studying multiple brain indices simultaneously helps illuminate the mechanisms and time-course of neural processing underlying concurrent sound segregation and may lead to further development and refinement of physiologically driven models of auditory scene analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exposure to low levels of jet-propulsion fuel impairs brainstem encoding of stimulus intensity.

PubMed

Guthrie, O'neil W; Xu, Helen; Wong, Brian A; McInturf, Shawn M; Reboulet, Jim E; Ortiz, Pedro A; Mattie, David R

2014-01-01

Jet propulsion fuel-8 (JP-8) is a kerosene-based fuel that is used in military jets. The U.S. Armed Services and North Atlantic Treaty Organization countries adopted JP-8 as a standard fuel source and the U.S. military alone consumes more than 2.5 billion gallons annually. Preliminary epidemiologic data suggested that JP-8 may interact with noise to induce hearing loss, and animal studies revealed damage to presynaptic sensory cells in the cochlea. In the current study, Long-Evans rats were divided into four experimental groups: control, noise only, JP-8 only, and JP-8 + noise. A subototoxic level of JP-8 was used alone or in combination with a nondamaging level of noise. Functional and structural assays of the presynaptic sensory cells combined with neurophysiologic studies of the cochlear nerve revealed that peripheral auditory function was not affected by individual exposures and there was no effect when the exposures were combined. However, the central auditory nervous system exhibited impaired brainstem encoding of stimulus intensity. These findings may represent important and major shifts in the theoretical framework that governs current understanding of jet fuel and/or jet fuel + noise-induced ototoxicity. From an epidemiologic perspective, results indicate that jet fuel exposure may exert consequences on auditory function that may be more widespread and insidious than what was previously shown. It is possible that a large population of military personnel who are suffering from the effects of jet fuel exposure may be misidentified because they would exhibit normal hearing thresholds but harbor a "hidden" brainstem dysfunction.

Noise-induced inner hair cell ribbon loss disturbs central arc mobilization: a novel molecular paradigm for understanding tinnitus.

PubMed

Singer, Wibke; Zuccotti, Annalisa; Jaumann, Mirko; Lee, Sze Chim; Panford-Walsh, Rama; Xiong, Hao; Zimmermann, Ulrike; Franz, Christoph; Geisler, Hyun-Soon; Köpschall, Iris; Rohbock, Karin; Varakina, Ksenya; Verpoorten, Sandrine; Reinbothe, Thomas; Schimmang, Thomas; Rüttiger, Lukas; Knipper, Marlies

2013-02-01

Increasing evidence shows that hearing loss is a risk factor for tinnitus and hyperacusis. Although both often coincide, a causal relationship between tinnitus and hyperacusis has not been shown. Currently, tinnitus and hyperacusis are assumed to be caused by elevated responsiveness in subcortical circuits. We examined both the impact of different degrees of cochlear damage and the influence of stress priming on tinnitus induction. We used (1) a behavioral animal model for tinnitus designed to minimize stress, (2) ribbon synapses in inner hair cells (IHCs) as a measure for deafferentation, (3) the integrity of auditory brainstem responses (ABR) to detect differences in stimulus-evoked neuronal activity, (4) the expression of the activity-regulated cytoskeletal protein, Arc, to identify long-lasting changes in network activity within the basolateral amygdala (BLA), hippocampal CA1, and auditory cortex (AC), and (5) stress priming to investigate the influence of corticosteroid on trauma-induced brain responses. We observed that IHC ribbon loss (deafferentation) leads to tinnitus when ABR functions remain reduced and Arc is not mobilized in the hippocampal CA1 and AC. If, however, ABR waves are functionally restored and Arc is mobilized, tinnitus does not occur. Both central response patterns were found to be independent of a profound threshold loss and could be shifted by the corticosterone level at the time of trauma. We, therefore, discuss the findings in the context of a history of stress that can trigger either an adaptive or nonadaptive brain response following injury.

Changes in the Response Properties of Inferior Colliculus Neurons Relating to Tinnitus

PubMed Central

Berger, Joel I.; Coomber, Ben; Wells, Tobias T.; Wallace, Mark N.; Palmer, Alan R.

2014-01-01

Tinnitus is often identified in animal models by using the gap prepulse inhibition of acoustic startle. Impaired gap detection following acoustic over-exposure (AOE) is thought to be caused by tinnitus “filling in” the gap, thus, reducing its salience. This presumably involves altered perception, and could conceivably be caused by changes at the level of the neocortex, i.e., cortical reorganization. Alternatively, reduced gap detection ability might reflect poorer temporal processing in the brainstem, caused by AOE; in which case, impaired gap detection would not be a reliable indicator of tinnitus. We tested the latter hypothesis by examining gap detection in inferior colliculus (IC) neurons following AOE. Seven of nine unilaterally noise-exposed guinea pigs exhibited behavioral evidence of tinnitus. In these tinnitus animals, neural gap detection thresholds (GDTs) in the IC significantly increased in response to broadband noise stimuli, but not to pure tones or narrow-band noise. In addition, when IC neurons were sub-divided according to temporal response profile (onset vs. sustained firing patterns), we found a significant increase in the proportion of onset-type responses after AOE. Importantly, however, GDTs were still considerably shorter than gap durations commonly used in objective behavioral tests for tinnitus. These data indicate that the neural changes observed in the IC are insufficient to explain deficits in behavioral gap detection that are commonly attributed to tinnitus. The subtle changes in IC neuron response profiles following AOE warrant further investigation. PMID:25346722

Effects of noise exposure on young adults with normal audiograms I: Electrophysiology.

PubMed

Prendergast, Garreth; Guest, Hannah; Munro, Kevin J; Kluk, Karolina; Léger, Agnès; Hall, Deborah A; Heinz, Michael G; Plack, Christopher J

2017-02-01

Noise-induced cochlear synaptopathy has been demonstrated in numerous rodent studies. In these animal models, the disorder is characterized by a reduction in amplitude of wave I of the auditory brainstem response (ABR) to high-level stimuli, whereas the response at threshold is unaffected. The aim of the present study was to determine if this disorder is prevalent in young adult humans with normal audiometric hearing. One hundred and twenty six participants (75 females) aged 18-36 were tested. Participants had a wide range of lifetime noise exposures as estimated by a structured interview. Audiometric thresholds did not differ across noise exposures up to 8 kHz, although 16-kHz audiometric thresholds were elevated with increasing noise exposure for females but not for males. ABRs were measured in response to high-pass (1.5 kHz) filtered clicks of 80 and 100 dB peSPL. Frequency-following responses (FFRs) were measured to 80 dB SPL pure tones from 240 to 285 Hz, and to 80 dB SPL 4 kHz pure tones amplitude modulated at frequencies from 240 to 285 Hz (transposed tones). The bandwidth of the ABR stimuli and the carrier frequency of the transposed tones were chosen to target the 3-6 kHz characteristic frequency region which is usually associated with noise damage in humans. The results indicate no relation between noise exposure and the amplitude of the ABR. In particular, wave I of the ABR did not decrease with increasing noise exposure as predicted. ABR wave V latency increased with increasing noise exposure for the 80 dB peSPL click. High carrier-frequency (envelope) FFR signal-to-noise ratios decreased as a function of noise exposure in males but not females. However, these correlations were not significant after the effects of age were controlled. The results suggest either that noise-induced cochlear synaptopathy is not a significant problem in young, audiometrically normal adults, or that the ABR and FFR are relatively insensitive to this disorder in young humans, although it is possible that the effects become more pronounced with age. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Brainstem origins for cortical 'what' and 'where' pathways in the auditory system.

PubMed

Kraus, Nina; Nicol, Trent

2005-04-01

We have developed a data-driven conceptual framework that links two areas of science: the source-filter model of acoustics and cortical sensory processing streams. The source-filter model describes the mechanics behind speech production: the identity of the speaker is carried largely in the vocal cord source and the message is shaped by the ever-changing filters of the vocal tract. Sensory processing streams, popularly called 'what' and 'where' pathways, are well established in the visual system as a neural scheme for separately carrying different facets of visual objects, namely their identity and their position/motion, to the cortex. A similar functional organization has been postulated in the auditory system. Both speaker identity and the spoken message, which are simultaneously conveyed in the acoustic structure of speech, can be disentangled into discrete brainstem response components. We argue that these two response classes are early manifestations of auditory 'what' and 'where' streams in the cortex. This brainstem link forges a new understanding of the relationship between the acoustics of speech and cortical processing streams, unites two hitherto separate areas in science, and provides a model for future investigations of auditory function.

Brainstem auditory responses to resolved and unresolved harmonics of a synthetic vowel in quiet and noise.

PubMed

Laroche, Marilyn; Dajani, Hilmi R; Prévost, François; Marcoux, André M

2013-01-01

This study investigated speech auditory brainstem responses (speech ABR) with variants of a synthetic vowel in quiet and in background noise. Its objectives were to study the noise robustness of the brainstem response at the fundamental frequency F0 and at the first formant F1, evaluate how the resolved/unresolved harmonics regions in speech contribute to the response at F0, and investigate the origin of the response at F0 to resolved and unresolved harmonics in speech. In total, 18 normal-hearing subjects (11 women, aged 18-33 years) participated in this study. Speech ABRs were recorded using variants of a 300 msec formant-synthesized /a/ vowel in quiet and in white noise. The first experiment employed three variants containing the first three formants F1 to F3, F1 only, and F2 and F3 only with relative formant levels following those reported in the literature. The second experiment employed three variants containing F1 only, F2 only, and F3 only, with the formants equalized to the same level and the signal-to-noise ratio (SNR) maintained at -5 dB. Overall response latency was estimated, and the amplitude and local SNR of the envelope following response at F0 and of the frequency following response at F1 were compared for the different stimulus variants in quiet and in noise. The response at F0 was more robust to noise than that at F1. There were no statistically significant differences in the response at F0 caused by the three stimulus variants in both experiments in quiet. However, the response at F0 with the variant dominated by resolved harmonics was more robust to noise than the response at F0 with the stimulus variants dominated by unresolved harmonics. The latencies of the responses in all cases were very similar in quiet, but the responses at F0 due to resolved and unresolved harmonics combined nonlinearly when both were present in the stimulus. Speech ABR has been suggested as a marker of central auditory processing. The results of this study support earlier work on the differential susceptibility to noise of the F0 and F1 components of the evoked response. In the case of F0, the results support the view that in speech, the pitch of resolved harmonics and that of unresolved harmonics are processed in different but interacting pathways that converge in the upper brainstem. Pitch plays an important role in speech perception, and speech ABR can offer a window into the neural extraction of the pitch of speech and how it may change with hearing impairment.

The effects of postnatal phthalate exposure on the development of auditory temporal processing in rats.

PubMed

Kim, Bong Jik; Kim, Jungyoon; Keoboutdy, Vanhnansy; Kwon, Ho-Jang; Oh, Seung-Ha; Jung, Jae Yun; Park, Il Yong; Paik, Ki Chung

2017-06-01

The central auditory pathway is known to continue its development during the postnatal critical periods and is shaped by experience and sensory inputs. Phthalate, a known neurotoxic material, has been reported to be associated with attention deficits in children, impacting many infant neurobehaviors. The objective of this study was to investigate the potential effects of neonatal phthalate exposure on the development of auditory temporal processing. Neonatal Sprague-Dawley rats were randomly assigned into two groups: The phthalate group (n = 6), and the control group (n = 6). Phthalate was given once per day from postnatal day 8 (P8) to P28. Upon completion, at P28, the Auditory Brainstem Response (ABR) and Gap Prepulse Inhibition of Acoustic Startle response (GPIAS) at each gap duration (2, 5, 10, 20, 50 and 80 ms) were measured, and gap detection threshold (GDT) was calculated. These outcomes were compared between the two groups. Hearing thresholds by ABR showed no significant differences at all frequencies between the two groups. Regarding GPIAS, no significant difference was observed, except at a gap duration of 20 ms (p = 0.037). The mean GDT of the phthalate group (44.0 ms) was higher than that of the control group (20.0 ms), but without statistical significance (p = 0.065). Moreover, the phthalate group tended to demonstrate more of a scattered distribution in the GDT group than the in the control group. Neonatal phthalate exposure may disrupt the development of auditory temporal processing in rats. Copyright © 2017 Elsevier B.V. All rights reserved.

The value of ASSR threshold-based bilateral hearing aid fitting in children with difficult or unreliable behavioral audiometry.

PubMed

Vlastarakos, Petros V; Vasileiou, Alexandra; Nikolopoulos, Thomas P

2017-12-01

We conducted an analysis to assess the relative contribution of auditory brainstem response (ABR) testing and auditory steady-state response (ASSR) testing in providing appropriate hearing aid fitting in hearing-impaired children with difficult or unreliable behavioral audiometry. Of 150 infants and children who had been referred to us for hearing assessment as part of a neonatal hearing screening and cochlear implantation program, we identified 5 who exhibited significant discrepancies between click-ABR and ASSR testing results and difficult or unreliable behavioral audiometry. Hearing aid fitting in pediatric cochlear implant candidates for a trial period of 3 to 6 months is a common practice in many implant programs, but monitoring the progress of the amplified infants and providing appropriate hearing aid fitting can be challenging. If we accept the premise that we can assess the linguistic progress of amplified infants with an acceptable degree of certainty, the auditory behavior that we are monitoring presupposes appropriate bilateral hearing aid fitting. This may become very challenging in young children, or even in older children with difficult or unreliable behavioral audiometry results. This challenge can be addressed by using data from both ABR and ASSR testing. Fitting attempts that employ data from only ABR testing provide amplification that involves the range of spoken language but is not frequency-specific. Hearing aid fitting should also incorporate and take into account ASSR data because reliance on ABR testing alone might compromise the validity of the monitoring process. In conclusion, we believe that ASSR threshold-based bilateral hearing aid fitting is necessary to provide frequency-specific amplification of hearing and appropriate propulsion in the prelinguistic vocalizations of monitored infants.

Hearing Loss in a Mouse Model of 22q11.2 Deletion Syndrome

PubMed Central

Fuchs, Jennifer C.; Zinnamon, Fhatarah A.; Taylor, Ruth R.; Ivins, Sarah; Scambler, Peter J.; Forge, Andrew; Tucker, Abigail S.; Linden, Jennifer F.

2013-01-01

22q11.2 Deletion Syndrome (22q11DS) arises from an interstitial chromosomal microdeletion encompassing at least 30 genes. This disorder is one of the most significant known cytogenetic risk factors for schizophrenia, and can also cause heart abnormalities, cognitive deficits, hearing difficulties, and a variety of other medical problems. The Df1/+ hemizygous knockout mouse, a model for human 22q11DS, recapitulates many of the deficits observed in the human syndrome including heart defects, impaired memory, and abnormal auditory sensorimotor gating. Here we show that Df1/+ mice, like human 22q11DS patients, have substantial rates of hearing loss arising from chronic middle ear infection. Auditory brainstem response (ABR) measurements revealed significant elevation of click-response thresholds in 48% of Df1/+ mice, often in only one ear. Anatomical and histological analysis of the middle ear demonstrated no gross structural abnormalities, but frequent signs of otitis media (OM, chronic inflammation of the middle ear), including excessive effusion and thickened mucosa. In mice for which both in vivo ABR thresholds and post mortem middle-ear histology were obtained, the severity of signs of OM correlated directly with the level of hearing impairment. These results suggest that abnormal auditory sensorimotor gating previously reported in mouse models of 22q11DS could arise from abnormalities in auditory processing. Furthermore, the findings indicate that Df1/+ mice are an excellent model for increased risk of OM in human 22q11DS patients. Given the frequently monaural nature of OM in Df1/+ mice, these animals could also be a powerful tool for investigating the interplay between genetic and environmental causes of OM. PMID:24244619

Hearing loss in a mouse model of 22q11.2 Deletion Syndrome.

PubMed

Fuchs, Jennifer C; Zinnamon, Fhatarah A; Taylor, Ruth R; Ivins, Sarah; Scambler, Peter J; Forge, Andrew; Tucker, Abigail S; Linden, Jennifer F

2013-01-01

22q11.2 Deletion Syndrome (22q11DS) arises from an interstitial chromosomal microdeletion encompassing at least 30 genes. This disorder is one of the most significant known cytogenetic risk factors for schizophrenia, and can also cause heart abnormalities, cognitive deficits, hearing difficulties, and a variety of other medical problems. The Df1/+ hemizygous knockout mouse, a model for human 22q11DS, recapitulates many of the deficits observed in the human syndrome including heart defects, impaired memory, and abnormal auditory sensorimotor gating. Here we show that Df1/+ mice, like human 22q11DS patients, have substantial rates of hearing loss arising from chronic middle ear infection. Auditory brainstem response (ABR) measurements revealed significant elevation of click-response thresholds in 48% of Df1/+ mice, often in only one ear. Anatomical and histological analysis of the middle ear demonstrated no gross structural abnormalities, but frequent signs of otitis media (OM, chronic inflammation of the middle ear), including excessive effusion and thickened mucosa. In mice for which both in vivo ABR thresholds and post mortem middle-ear histology were obtained, the severity of signs of OM correlated directly with the level of hearing impairment. These results suggest that abnormal auditory sensorimotor gating previously reported in mouse models of 22q11DS could arise from abnormalities in auditory processing. Furthermore, the findings indicate that Df1/+ mice are an excellent model for increased risk of OM in human 22q11DS patients. Given the frequently monaural nature of OM in Df1/+ mice, these animals could also be a powerful tool for investigating the interplay between genetic and environmental causes of OM.

Histopathologic response of the immature rat to diffuse traumatic brain injury.

PubMed

Adelson, P D; Jenkins, L W; Hamilton, R L; Robichaud, P; Tran, M P; Kochanek, P M

2001-10-01

The purpose of this study was to characterize the histopathologic response of rats at postnatal day (PND) 17 following an impact-acceleration diffuse traumatic brain injury (TBI) using a 150-g/2-meter injury as previously described. This injury produces acute neurologic and physiologic derangements as well as enduring motor and Morris water maze (MWM) functional deficits. Histopathologic studies of perfusion-fixed brains were performed by gross examination and light microscopy using hematoxylin and eosin, Bielschowsky silver stain, and glial fibrillary acidic protein (GFAP) immunohistochemistry at 1, 3, 7, 28, and 90 day after injury. Gross pathologic examination revealed diffuse subarachnoid hemorrhage (SAH) at 1-3 days but minimal supratentorial intraparenchymal hemorrhage. Petechial hemorrhages were noted in ventral brainstem segments and in the cerebellum. After 1-3-day survivals, light microscopy revealed diffuse SAH and intraventricular hemorrhage (IVH), mild edema, significant axonal injury, reactive astrogliosis, and localized midline cerebellar hemorrhage. Axonal injury most commonly occurred in the long ascending and descending fiber tracts of the brainstem and occasionally in the forebrain, and was maximal at 3 days, but present until 7 days after injury. Reactive astrocytes were similarly found both in location and timing, but were also significantly identified in the hippocampus, white matter tracts, and corpus callosum. Typically, TBI produced significant diffuse SAH accompanied by cerebral and brainstem astrogliosis and axonal injury without obvious neuronal loss. Since this injury produces some pathologic changes with sustained functional deficits similar to TBI in infants and children, it should be useful for the further study of the pathophysiology and therapy of diffuse TBI and brainstem injury in the immature brain.

The auditory cross-section (AXS) test battery: A new way to study afferent/efferent relations linking body periphery (ear, voice, heart) with brainstem and cortex

NASA Astrophysics Data System (ADS)

Lauter, Judith

2002-05-01

Several noninvasive methods are available for studying the neural bases of human sensory-motor function, but their cost is prohibitive for many researchers and clinicians. The auditory cross section (AXS) test battery utilizes relatively inexpensive methods, yet yields data that are at least equivalent, if not superior in some applications, to those generated by more expensive technologies. The acronym emphasizes access to axes-the battery makes it possible to assess dynamic physiological relations along all three body-brain axes: rostro-caudal (afferent/efferent), dorso-ventral, and right-left, on an individually-specific basis, extending from cortex to the periphery. For auditory studies, a three-level physiological ear-to-cortex profile is generated, utilizing (1) quantitative electroencephalography (qEEG); (2) the repeated evoked potentials version of the auditory brainstem response (REPs/ABR); and (3) otoacoustic emissions (OAEs). Battery procedures will be explained, and sample data presented illustrating correlated multilevel changes in ear, voice, heart, brainstem, and cortex in response to circadian rhythms, and challenges with substances such as antihistamines and Ritalin. Potential applications for the battery include studies of central auditory processing, reading problems, hyperactivity, neural bases of voice and speech motor control, neurocardiology, individually-specific responses to medications, and the physiological bases of tinnitus, hyperacusis, and related treatments.

Test-retest reliability of speech-evoked auditory brainstem response in healthy children at a low sensation level.

PubMed

Zakaria, Mohd Normani; Jalaei, Bahram

2017-11-01

Auditory brainstem responses evoked by complex stimuli such as speech syllables have been studied in normal subjects and subjects with compromised auditory functions. The stability of speech-evoked auditory brainstem response (speech-ABR) when tested over time has been reported but the literature is limited. The present study was carried out to determine the test-retest reliability of speech-ABR in healthy children at a low sensation level. Seventeen healthy children (6 boys, 11 girls) aged from 5 to 9 years (mean = 6.8 ± 3.3 years) were tested in two sessions separated by a 3-month period. The stimulus used was a 40-ms syllable /da/ presented at 30 dB sensation level. As revealed by pair t-test and intra-class correlation (ICC) analyses, peak latencies, peak amplitudes and composite onset measures of speech-ABR were found to be highly replicable. Compared to other parameters, higher ICC values were noted for peak latencies of speech-ABR. The present study was the first to report the test-retest reliability of speech-ABR recorded at low stimulation levels in healthy children. Due to its good stability, it can be used as an objective indicator for assessing the effectiveness of auditory rehabilitation in hearing-impaired children in future studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization and Reduction of Cardiac- and Respiratory-Induced Noise as a Function of the Sampling Rate (TR) in fMRI

PubMed Central

Cordes, Dietmar; Nandy, Rajesh R.; Schafer, Scott; Wager, Tor D.

2014-01-01

It has recently been shown that both high-frequency and low-frequency cardiac and respiratory noise sources exist throughout the entire brain and can cause significant signal changes in fMRI data. It is also known that the brainstem, basal forebrain and spinal cord area are problematic for fMRI because of the magnitude of cardiac-induced pulsations at these locations. In this study, the physiological noise contributions in the lower brain areas (covering the brainstem and adjacent regions) are investigated and a novel method is presented for computing both low-frequency and high-frequency physiological regressors accurately for each subject. In particular, using a novel optimization algorithm that penalizes curvature (i.e. the second derivative) of the physiological hemodynamic response functions, the cardiac -and respiratory-related response functions are computed. The physiological noise variance is determined for each voxel and the frequency-aliasing property of the high-frequency cardiac waveform as a function of the repetition time (TR) is investigated. It is shown that for the brainstem and other brain areas associated with large pulsations of the cardiac rate, the temporal SNR associated with the low-frequency range of the BOLD response has maxima at subject-specific TRs. At these values, the high-frequency aliased cardiac rate can be eliminated by digital filtering without affecting the BOLD-related signal. PMID:24355483

LANGUAGE EXPERIENCE SHAPES PROCESSING OF PITCH RELEVANT INFORMATION IN THE HUMAN BRAINSTEM AND AUDITORY CORTEX: ELECTROPHYSIOLOGICAL EVIDENCE.

PubMed

Krishnan, Ananthanarayan; Gandour, Jackson T

2014-12-01

Pitch is a robust perceptual attribute that plays an important role in speech, language, and music. As such, it provides an analytic window to evaluate how neural activity relevant to pitch undergo transformation from early sensory to later cognitive stages of processing in a well coordinated hierarchical network that is subject to experience-dependent plasticity. We review recent evidence of language experience-dependent effects in pitch processing based on comparisons of native vs. nonnative speakers of a tonal language from electrophysiological recordings in the auditory brainstem and auditory cortex. We present evidence that shows enhanced representation of linguistically-relevant pitch dimensions or features at both the brainstem and cortical levels with a stimulus-dependent preferential activation of the right hemisphere in native speakers of a tone language. We argue that neural representation of pitch-relevant information in the brainstem and early sensory level processing in the auditory cortex is shaped by the perceptual salience of domain-specific features. While both stages of processing are shaped by language experience, neural representations are transformed and fundamentally different at each biological level of abstraction. The representation of pitch relevant information in the brainstem is more fine-grained spectrotemporally as it reflects sustained neural phase-locking to pitch relevant periodicities contained in the stimulus. In contrast, the cortical pitch relevant neural activity reflects primarily a series of transient temporal neural events synchronized to certain temporal attributes of the pitch contour. We argue that experience-dependent enhancement of pitch representation for Chinese listeners most likely reflects an interaction between higher-level cognitive processes and early sensory-level processing to improve representations of behaviorally-relevant features that contribute optimally to perception. It is our view that long-term experience shapes this adaptive process wherein the top-down connections provide selective gating of inputs to both cortical and subcortical structures to enhance neural responses to specific behaviorally-relevant attributes of the stimulus. A theoretical framework for a neural network is proposed involving coordination between local, feedforward, and feedback components that can account for experience-dependent enhancement of pitch representations at multiple levels of the auditory pathway. The ability to record brainstem and cortical pitch relevant responses concurrently may provide a new window to evaluate the online interplay between feedback, feedforward, and local intrinsic components in the hierarchical processing of pitch relevant information.

LANGUAGE EXPERIENCE SHAPES PROCESSING OF PITCH RELEVANT INFORMATION IN THE HUMAN BRAINSTEM AND AUDITORY CORTEX: ELECTROPHYSIOLOGICAL EVIDENCE

PubMed Central

Krishnan, Ananthanarayan; Gandour, Jackson T.

2015-01-01

Pitch is a robust perceptual attribute that plays an important role in speech, language, and music. As such, it provides an analytic window to evaluate how neural activity relevant to pitch undergo transformation from early sensory to later cognitive stages of processing in a well coordinated hierarchical network that is subject to experience-dependent plasticity. We review recent evidence of language experience-dependent effects in pitch processing based on comparisons of native vs. nonnative speakers of a tonal language from electrophysiological recordings in the auditory brainstem and auditory cortex. We present evidence that shows enhanced representation of linguistically-relevant pitch dimensions or features at both the brainstem and cortical levels with a stimulus-dependent preferential activation of the right hemisphere in native speakers of a tone language. We argue that neural representation of pitch-relevant information in the brainstem and early sensory level processing in the auditory cortex is shaped by the perceptual salience of domain-specific features. While both stages of processing are shaped by language experience, neural representations are transformed and fundamentally different at each biological level of abstraction. The representation of pitch relevant information in the brainstem is more fine-grained spectrotemporally as it reflects sustained neural phase-locking to pitch relevant periodicities contained in the stimulus. In contrast, the cortical pitch relevant neural activity reflects primarily a series of transient temporal neural events synchronized to certain temporal attributes of the pitch contour. We argue that experience-dependent enhancement of pitch representation for Chinese listeners most likely reflects an interaction between higher-level cognitive processes and early sensory-level processing to improve representations of behaviorally-relevant features that contribute optimally to perception. It is our view that long-term experience shapes this adaptive process wherein the top-down connections provide selective gating of inputs to both cortical and subcortical structures to enhance neural responses to specific behaviorally-relevant attributes of the stimulus. A theoretical framework for a neural network is proposed involving coordination between local, feedforward, and feedback components that can account for experience-dependent enhancement of pitch representations at multiple levels of the auditory pathway. The ability to record brainstem and cortical pitch relevant responses concurrently may provide a new window to evaluate the online interplay between feedback, feedforward, and local intrinsic components in the hierarchical processing of pitch relevant information. PMID:25838636

Repeated antenatal corticosteroid treatments adversely affect neural transmission time and auditory thresholds in laboratory rats.

PubMed

Church, M W; Adams, B R; Anumba, J I; Jackson, D A; Kruger, M L; Jen, K-L C

2012-01-01

Antenatal corticosteroid (AC) treatment is given to pregnant women at risk for preterm birth to reduce infant morbidity and mortality by enhancing lung and brain maturation. However, there is no accepted regimen on how frequently AC treatments should be given and some studies found that repeated AC treatments can cause growth retardation and brain damage. Our goal was to assess the dose-dependent effects of repeated AC treatment and estimate the critical number of AC courses to cause harmful effects on the auditory brainstem response (ABR), a sensitive measure of brain development, neural transmission and hearing loss. We hypothesized that repeated AC treatment would have harmful effects on the offspring's ABRs and growth only if more than 3 AC treatment courses were given. To test this hypothesis, pregnant Wistar rats were given either a high regimen of AC (HAC), a moderate regimen (MAC), a low regimen (LAC), or saline (SAL). An untreated control (CON) group was also used. Simulating the clinical condition, the HAC dams received 0.2mg/kg Betamethasone (IM) twice daily for 6 days during gestation days (GD) 17-22. The MAC dams received 3 days of AC treatment followed by 3 days of saline treatment on GD 17-19 and GD 20-22, respectively. The LAC dams received 1 day of AC treatment followed by 5 days of saline treatment on GD 17 and GD 18-22, respectively. The SAL dams received 6 days of saline treatment from GD 17 to 22 (twice daily, isovolumetric to the HAC injections, IM). The offspring were ABR-tested on postnatal day 24. Results indicated that the ABR's P4 latencies (neural transmission time) were significantly prolonged (worse) in the HAC pups and that ABR's thresholds were significantly elevated (worse) in the HAC and MAC pups when compared to the CON pups. The HAC and MAC pups were also growth retarded and had higher postnatal mortality than the CON pups. The SAL and LAC pups showed little or no adverse effects. In conclusion, repeated AC treatment had harmful effects on the rat offspring's ABRs, postnatal growth and survival. The prolonged ABR latencies reflect slowed neural transmission times along the auditory nerve and brainstem auditory pathway. The elevated ABR thresholds reflect hearing deficits. We concluded that repeated AC treatment can have harmful neurological, sensory and developmental effects on the rat offspring. These effects should be considered when weighing the benefits and risks of repeated AC treatment and when monitoring and managing the prenatally exposed child for possible adverse effects. Copyright © 2011 Elsevier Inc. All rights reserved.

Bilingualism increases neural response consistency and attentional control: Evidence for sensory and cognitive coupling

PubMed Central

Krizman, Jennifer; Skoe, Erika; Marian, Viorica; Kraus, Nina

2014-01-01

Auditory processing is presumed to be influenced by cognitive processes – including attentional control – in a top-down manner. In bilinguals, activation of both languages during daily communication hones inhibitory skills, which subsequently bolster attentional control. We hypothesize that the heightened attentional demands of bilingual communication strengthens connections between cognitive (i.e., attentional control) and auditory processing, leading to greater across-trial consistency in the auditory evoked response (i.e., neural consistency) in bilinguals. To assess this, we collected passively-elicited auditory evoked responses to the syllable [da] and separately obtained measures of attentional control and language ability in adolescent Spanish-English bilinguals and English monolinguals. Bilinguals demonstrated enhanced attentional control and more consistent brainstem and cortical responses. In bilinguals, but not monolinguals, brainstem consistency tracked with language proficiency and attentional control. We interpret these enhancements in neural consistency as the outcome of strengthened attentional control that emerged from experience communicating in two languages. PMID:24413593

Astragaloside IV inhibits apoptotic cell death in the guinea pig cochlea exposed to impulse noise.

PubMed

Xiong, Min; He, Qinglian; Lai, Huangwen; Wang, Jian

2012-05-01

The results suggest that the beneficial effect of astragaloside IV on impulse noise-induced hearing loss may be due to its ability to inhibit reactive oxygen species (ROS) and prevent apoptosis. Astragaloside IV is the major active constituent of Astragalus membranaceus, which has been widely used for the treatment of diseases in China for its antioxidant properties. ROS and apoptosis are involved in damage induced by impulse noise trauma. We aimed to investigate if the beneficial effects of astragaloside IV on cochlea exposed to impulse noise are associated with the inhibition of ROS and the decrease in apoptosis. 4-Hydroxynonenal (HNE) was used as the marker of ROS. Active-caspase-3 (cas-3) served as a marker for apoptosis. 4HNE and cas-3 were determined immunohistochemically. Guinea pigs in the experimental group were administered astragaloside IV intragastrically. Auditory thresholds were assessed by sound-evoked auditory brainstem response (ABR) 72 h before and after exposure to impulse noise. The results showed that astragaloside IV significantly reduced ABR deficits, and decreased the expression of ROS and cas-3.

Safety, reliability, and operability of cochlear implant electrode arrays coated with biocompatible polymer.

PubMed

Kinoshita, Makoto; Kikkawa, Yayoi S; Sakamoto, Takashi; Kondo, Kenji; Ishihara, Kazuhiko; Konno, Tomohiro; Pawsey, Nick; Yamasoba, Tatsuya

2015-04-01

Polymer-coated electrodes can reduce surgically-induced trauma associated with the insertion of a cochlear implant (CI) electrode array. To evaluate if insertion trauma in CI surgery can be reduced by using electrode arrays coated with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer. We analyzed characteristics of the Contour Advance electrode arrays coated with MPC polymer. To assess surgical trauma during electrode insertion, polymer-coated or uncoated (n = 5 each) animal electrode arrays were implanted in guinea pig cochleae and operability and electrophysiological and histological changes were assessed. Under light and scanning electron microscopy, polymer-coated electrodes did not appear different from uncoated electrodes, and no change was observed after mechanical stressing of the arrays. Electrode insertion was significantly easier when polymer-coated electrodes were used. Auditory brainstem response (ABR) thresholds did not differ between groups, but p1-n1 amplitudes of the coated group were larger compared with the uncoated group at 32 kHz at 28 days after surgery. The survival of outer hair cells and spiral ganglion cells was significantly greater in the polymer-coated group.

Hearing dysfunction in heterozygous Mitf(Mi-wh) /+ mice, a model for Waardenburg syndrome type 2 and Tietz syndrome.

PubMed

Ni, Christina; Zhang, Deming; Beyer, Lisa A; Halsey, Karin E; Fukui, Hideto; Raphael, Yehoash; Dolan, David F; Hornyak, Thomas J

2013-01-01

The human deafness-pigmentation syndromes, Waardenburg syndrome (WS) type 2a, and Tietz syndrome are characterized by profound deafness but only partial cutaneous pigmentary abnormalities. Both syndromes are caused by mutations in MITF. To illuminate differences between cutaneous and otic melanocytes in these syndromes, their development and survival in heterozygous Microphthalmia-White (Mitf(Mi-wh) /+) mice were studied and hearing function of these mice characterized. Mitf(Mi-wh) /+ mice have a profound hearing deficit, characterized by elevated auditory brainstem response thresholds, reduced distortion product otoacoustic emissions, absent endocochlear potential, loss of outer hair cells, and stria vascularis abnormalities. Mitf(Mi-wh) /+ embryos have fewer melanoblasts during embryonic development than their wild-type littermates. Although cochlear melanocytes are present at birth, they disappear from the Mitf(Mi-wh) /+ cochlea between P1 and P7. These findings may provide insight into the mechanism of melanocyte and hearing loss in human deafness-pigmentation syndromes such as WS and Tietz syndrome and illustrate differences between otic and follicular melanocytes. © 2012 John Wiley & Sons A/S.

Morphology of subcortical brain nuclei is associated with autonomic function in healthy humans.

PubMed

Ruffle, James K; Coen, Steven J; Giampietro, Vincent; Williams, Steven C R; Apkarian, A Vania; Farmer, Adam D; Aziz, Qasim

2018-01-01

The autonomic nervous system (ANS) is a brain body interface which serves to maintain homeostasis by influencing a plethora of physiological processes, including metabolism, cardiorespiratory regulation and nociception. Accumulating evidence suggests that ANS function is disturbed in numerous prevalent clinical disorders, including irritable bowel syndrome and fibromyalgia. While the brain is a central hub for regulating autonomic function, the association between resting autonomic activity and subcortical morphology has not been comprehensively studied and thus was our aim. In 27 healthy subjects [14 male and 13 female; mean age 30 years (range 22-53 years)], we quantified resting ANS function using validated indices of cardiac sympathetic index (CSI) and parasympathetic cardiac vagal tone (CVT). High resolution structural magnetic resonance imaging scans were acquired, and differences in subcortical nuclei shape, that is, 'deformation', contingent on resting ANS activity were investigated. CSI positively correlated with outward deformation of the brainstem, right nucleus accumbens, right amygdala and bilateral pallidum (all thresholded to corrected P < 0.05). In contrast, parasympathetic CVT negatively correlated with inward deformation of the right amygdala and pallidum (all thresholded to corrected P < 0.05). Left and right putamen volume positively correlated with CVT (r = 0.62, P = 0.0047 and r = 0.59, P = 0.008, respectively), as did the brainstem (r = 0.46, P = 0.049). These data provide novel evidence that resting autonomic state is associated with differences in the shape and volume of subcortical nuclei. Thus, subcortical morphological brain differences in various disorders may partly be attributable to perturbation in autonomic function. Further work is warranted to investigate these findings in clinical populations. Hum Brain Mapp 39:381-392, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Neural connectivity of the posterior body of the fornix in the human brain: diffusion tensor imaging study.

PubMed

Jang, Sung Ho; Kwon, Hyeok Gyu

2013-08-09

Little is known about the neural connectivity of the fornix in the human brain. In the current study, using diffusion tensor imaging, we attempted to investigate the neural connectivity of the posterior body of the fornix in the normal human brain. A total of 43 healthy subjects were recruited for this study. DTIs were acquired using a sensitivity-encoding head coil at 1.5T. For connectivity of the posterior body of the fornix, a seed region of interest was used on the posterior body of the fornix. Connectivity was defined as the incidence of connection between the posterior body of the fornix and any neural structure of the brain at the threshold of 5, 25, and 50 streamline. At the threshold of 5, 25, and 50, the posterior body of the fornix showed connectivity to the precentral gyrus (37%, 19%, and 15%), the postcentral gyrus (25%, 11.5%, and 7%), the posterior parietal cortex (16.5%, 5%, and 5%), the brainstem (12%, 4.5%, and 3.5%), the crus of the fornix (34%, 10.5%, and 7%), the contralateral splenium of the corpus callosum (12.5%, 5%, and 0%), and the ipsilateral splenium of the CC (69.8%%, 33.7%, and 23.3%), respectively. Findings of this study showed that the posterior body of the fornix had connectivity with the cerebral cortex, the brainstem, the fornical crus, and the contralateral splenium through the splenium of the corpus callosum in normal subjects. We believe that the results of this study would be helpful in investigation of the neural network related to memory and recovery mechanisms following fornical injury in the human brain. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A novel DARS2 mutation in a Japanese patient with leukoencephalopathy with brainstem and spinal cord involvement but no lactate elevation

PubMed Central

Shimojima, Keiko; Higashiguchi, Takafumi; Kishimoto, Kanako; Miyatake, Satoko; Miyake, Noriko; Takanashi, Jun-ichi; Matsumoto, Naomichi; Yamamoto, Toshiyuki

2017-01-01

The mitochondrial aspartyl-tRNA synthetase 2 gene (DARS2) is responsible for leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL). A Japanese patient with LBSL showed compound heterozygous DARS2 mutations c.358_359delinsTC (p.Gly120Ser) and c.228-15C>G (splicing error). This provides further evidence that most patients with LBSL show compound heterozygous mutations in DARS2 in association with a common splicing mutation in the splicing acceptor site of intron 2. PMID:29138691

Chronic lead exposure induces cochlear oxidative stress and potentiates noise-induced hearing loss.

PubMed

Jamesdaniel, Samson; Rosati, Rita; Westrick, Judy; Ruden, Douglas M

2018-08-01

Acquired hearing loss is caused by complex interactions of multiple environmental risk factors, such as elevated levels of lead and noise, which are prevalent in urban communities. This study delineates the mechanism underlying lead-induced auditory dysfunction and its potential interaction with noise exposure. Young-adult C57BL/6 mice were exposed to: 1) control conditions; 2) 2 mM lead acetate in drinking water for 28 days; 3) 90 dB broadband noise 2 h/day for two weeks; and 4) both lead and noise. Blood lead levels were measured by inductively coupled plasma mass spectrometry analysis (ICP-MS) lead-induced cochlear oxidative stress signaling was assessed using targeted gene arrays, and the hearing thresholds were assessed by recording auditory brainstem responses. Chronic lead exposure downregulated cochlear Sod1, Gpx1, and Gstk1, which encode critical antioxidant enzymes, and upregulated ApoE, Hspa1a, Ercc2, Prnp, Ccl5, and Sqstm1, which are indicative of cellular apoptosis. Isolated exposure to lead or noise induced 8-12 dB and 11-25 dB shifts in hearing thresholds, respectively. Combined exposure induced 18-30 dB shifts, which was significantly higher than that observed with isolated exposures. This study suggests that chronic exposure to lead induces cochlear oxidative stress and potentiates noise-induced hearing impairment, possibly through parallel pathways. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Targeted Mutation of the Gene for Cellular Glutathione Peroxidase (Gpx1) Increases Noise-Induced Hearing Loss in Mice

PubMed Central

McFadden, Sandra L.; Ding, Da-Lian; Lear, Patricia M.; Ho, Ye-Shih

2000-01-01

Reactive oxygen species (ROS) and oxidative stress have been implicated in cochlear injury following loud noise and ototoxins. Genetic mutations that impair antioxidant defenses would be expected to increase cochlear injury following acute insults and to contribute to cumulative injury that presents as age-related hearing loss. We examined whether genetically based deficiency of cellular glutathione peroxidase, a major antioxidant enzyme, increases noise-induced hearing loss in mice. Two-month-old "knockout" mice with a targeted inactivating mutation of the gene coding for glutathione peroxidase (Gpx1) and wild type controls were exposed to broadband noise for one hour at 110 dB SPL. Auditory brainstem response (ABR) thresholds at test frequencies ranging from 5 to 40 kHz were obtained two and four weeks after exposure to determine the stable permanent component of the hearing loss. Depending on test frequency, Gpx1 knockout mice showed up to 16 dB higher ABR thresholds prior to noise exposure, and up to 15 dB greater noise-induced hearing loss, compared with controls. Within the cochlear base, there was also a significant contribution of the knockout to inner and outer hair cell loss, as well as nerve fiber loss. Our results support a link between genetic impairment of antioxidant defenses, vulnerability of the cochlea injury, and cochlear degeneration. Such impairment produces characteristics expected of some mutations associated with age-related hearing loss and offers one possible mechanism for their action. PMID:11545230

Mechanisms of Hearing Loss after Blast Injury to the Ear

PubMed Central

Cho, Sung-Il; Gao, Simon S.; Xia, Anping; Wang, Rosalie; Salles, Felipe T.; Raphael, Patrick D.; Abaya, Homer; Wachtel, Jacqueline; Baek, Jongmin; Jacobs, David; Rasband, Matthew N.; Oghalai, John S.

2013-01-01

Given the frequent use of improvised explosive devices (IEDs) around the world, the study of traumatic blast injuries is of increasing interest. The ear is the most common organ affected by blast injury because it is the body’s most sensitive pressure transducer. We fabricated a blast chamber to re-create blast profiles similar to that of IEDs and used it to develop a reproducible mouse model to study blast-induced hearing loss. The tympanic membrane was perforated in all mice after blast exposure and found to heal spontaneously. Micro-computed tomography demonstrated no evidence for middle ear or otic capsule injuries; however, the healed tympanic membrane was thickened. Auditory brainstem response and distortion product otoacoustic emission threshold shifts were found to be correlated with blast intensity. As well, these threshold shifts were larger than those found in control mice that underwent surgical perforation of their tympanic membranes, indicating cochlear trauma. Histological studies one week and three months after the blast demonstrated no disruption or damage to the intra-cochlear membranes. However, there was loss of outer hair cells (OHCs) within the basal turn of the cochlea and decreased spiral ganglion neurons (SGNs) and afferent nerve synapses. Using our mouse model that recapitulates human IED exposure, our results identify that the mechanisms underlying blast-induced hearing loss does not include gross membranous rupture as is commonly believed. Instead, there is both OHC and SGN loss that produce auditory dysfunction. PMID:23840874

The modulation rate transfer function of a harbour porpoise (Phocoena phocoena).

PubMed

Linnenschmidt, Meike; Wahlberg, Magnus; Damsgaard Hansen, Janni

2013-02-01

During echolocation, toothed whales produce ultrasonic clicks at extremely rapid rates and listen for the returning echoes. The auditory brainstem response (ABR) duration was evaluated in terms of latency between single peaks: 5.5 ms (from peak I to VII), 3.4 ms (I-VI), and 1.4 ms (II-IV). In comparison to the killer whale and the bottlenose dolphin, the ABR of the harbour porpoise has shorter intervals between the peaks and consequently a shorter ABR duration. This indicates that the ABR duration and peak latencies are possibly related to the relative size of the auditory structures of the central nervous system and thus to the animal's size. The ABR to a sinusoidal amplitude modulated stimulus at 125 kHz (sensitivity threshold 63 dB re 1 μPa rms) was evaluated to determine the modulation rate transfer function of a harbour porpoise. The ABR showed distinct envelope following responses up to a modulation rate of 1,900 Hz. The corresponding calculated equivalent rectangular duration of 263 μs indicates a good temporal resolution in the harbour porpoise auditory system similar to the one for the bottlenose dolphin. The results explain how the harbour porpoise can follow clicks and echoes during echolocation with very short inter click intervals.

Sensory coding and cognitive processing of sound in Veterans with blast exposure

PubMed Central

Bressler, Scott; Goldberg, Hannah; Shinn-Cunningham, Barbara

2017-01-01

Recent anecdotal reports from VA audiology clinics as well as a few published studies have identified a sub-population of Service Members seeking treatment for problems communicating in everyday, noisy listening environments despite having normal to near-normal hearing thresholds. Because of their increased risk of exposure to dangerous levels of prolonged noise and transient explosive blast events, communication problems in these soldiers could be due to either hearing loss (traditional or “hidden”) in the auditory sensory periphery or from blast-induced injury to cortical networks associated with attention. We found that out of the 14 blast-exposed Service Members recruited for this study, 12 had hearing thresholds in the normal to near-normal range. A majority of these participants reported having problems specifically related to failures with selective attention. Envelope following responses (EFRs) measuring neural coding fidelity of the auditory brainstem to suprathreshold sounds were similar between blast-exposed and non-blast controls. Blast-exposed subjects performed substantially worse than non-blast controls in an auditory selective attention task in which listeners classified the melodic contour (rising, falling, or “zig-zagging”) of one of three simultaneous, competing tone sequences. Salient pitch and spatial differences made for easy segregation of the three concurrent melodies. Poor performance in the blast-exposed subjects was associated with weaker evoked response potentials (ERPs) in frontal EEG channels, as well as a failure of attention to enhance the neural responses evoked by a sequence when it was the target compared to when it was a distractor. These results suggest that communication problems in these listeners cannot be explained by compromised sensory representations in the auditory periphery, but rather point to lingering blast-induced damage to cortical networks implicated in the control of attention. Because all study participants also suffered from post-traumatic disorder (PTSD), follow-up studies are required to tease apart the contributions of PTSD and blast-induced injury on cognitive performance. PMID:27815131

Temporary Hearing Threshold Shift in Healthy Volunteers with Hearing Protection Caused by Acoustic Noise Exposure during 3-T Multisequence MR Neuroimaging.

PubMed

Jin, Chao; Li, Huan; Li, Xianjun; Wang, Miaomiao; Liu, Congcong; Guo, Jianxin; Yang, Jian

2018-02-01

Purpose To determine whether a single 51-minute exposure to acoustic noise during 3-T multisequence magnetic resonance (MR) neuroimaging could affect the hearing threshold of healthy adults with earplugs and sponge mats as hearing protection. Materials and Methods With earplugs and motion-refraining sponge mats as hearing protection, 26 healthy young adults underwent 3-T MR neuroimaging imaging that included T1-weighted three-dimensional gradient-echo sequence, T2-weighted fast spin-echo sequence, diffusion-tensor imaging, diffusion-kurtosis imaging, T2*-weighted three-dimensional multiecho gradient-echo sequence, and blood oxygen level-dependent imaging. Automated auditory brainstem response (ABR) was used to measure the hearing thresholds within 24 hours before, within 20 minutes after, and 25 days after the MR examination. One-way repeated-measure analysis of variance with Bonferroni adjustment was used to compare automated ABR results among the three tests and partial η 2 (η p 2 ) was reported as a measure of effect size. Results Automated ABR results showed significantly increased mean threshold shift of 5.0 dB ± 8.1 (standard deviation) (left ear: 4.8 dB ± 9.2 [95% confidence interval: 1.09, 8.53], η p 2 = 0.221, P = .013; right ear: 5.2 dB ± 6.9 [95% confidence interval: 2.36, 8.02], η p 2 = 0.364, P = .001) immediately after the MR examination compared with the baseline study. This shift is below the temporary threshold shift of 40-50 dB that is associated with cochlea nerve changes. Automated ABR obtained at day 25 after MR imaging showed no significant differences from baseline (left ear: -2.3 dB ± 8.6 [95% confidence interval: -5.79, 1.78], η p 2 = 0.069, P = .185; right ear: 0.4 dB ± 7.3 [95% confidence interval: -3.35, 2.58], η p 2 = 0.003, P = .791). Conclusion A 3-T MR neuroimaging examination with the acoustic noise at equivalent sound pressure level of 103.5-111.3 dBA lasting 51 minutes can cause temporary hearing threshold shift in healthy volunteers with hearing protection. © RSNA, 2017.

BAER - brainstem auditory evoked response

MedlinePlus

... Updated by: Sumana Jothi, MD, specialist in laryngology, Assistant Clinical Professor, UCSF Otolaryngology, NCHCS VA, SFVA, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, ...

Auditory brainstem response in neonates: influence of gender and weight/gestational age ratio

PubMed Central

Angrisani, Rosanna M. Giaffredo; Bautzer, Ana Paula D.; Matas, Carla Gentile; de Azevedo, Marisa Frasson

2013-01-01

OBJECTIVE: To investigate the influence of gender and weight/gestational age ratio on the Auditory Brainstem Response (ABR) in preterm (PT) and term (T) newborns. METHODS: 176 newborns were evaluated by ABR; 88 were preterm infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). The preterm infants were compared to 88 term infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). All newborns had bilateral presence of transient otoacoustic emissions and type A tympanometry. RESULTS: No interaural differences were found. ABR response did not differentiate newborns regarding weight/gestational age in males and females. Term newborn females showed statistically shorter absolute latencies (except on wave I) than males. This finding did not occur in preterm infants, who had longer latencies than term newborns, regardless of gender. CONCLUSIONS: Gender and gestational age influence term infants' ABR, with lower responses in females. The weight/gestational age ratio did not influence ABR response in either groups. PMID:24473955

Musicians and tone-language speakers share enhanced brainstem encoding but not perceptual benefits for musical pitch

PubMed Central

Bidelman, Gavin M.; Gandour, Jackson T.; Krishnan, Ananthanarayan

2011-01-01

Behavioral and neurophysiological transfer effects from music experience to language processing are well-established but it is currently unclear whether or not linguistic expertise (e.g., speaking a tone language) benefits music-related processing and its perception. Here, we compare brainstem responses of English-speaking musicians/non-musicians and native speakers of Mandarin Chinese elicited by tuned and detuned musical chords, to determine if enhancements in subcortical processing translate to improvements in the perceptual discrimination of musical pitch. Relative to non-musicians, both musicians and Chinese had stronger brainstem representation of the defining pitches of musical sequences. In contrast, two behavioral pitch discrimination tasks revealed that neither Chinese nor non-musicians were able to discriminate subtle changes in musical pitch with the same accuracy as musicians. Pooled across all listeners, brainstem magnitudes predicted behavioral pitch discrimination performance but considering each group individually, only musicians showed connections between neural and behavioral measures. No brain-behavior correlations were found for tone language speakers or non-musicians. These findings point to a dissociation between subcortical neurophysiological processing and behavioral measures of pitch perception in Chinese listeners. We infer that sensory-level enhancement of musical pitch information yields cognitive-level perceptual benefits only when that information is behaviorally relevant to the listener. PMID:21835531

Phrenic nerve deficits and neurological immunopathology associated with acute West Nile virus infection in mice and hamsters.

PubMed

Zukor, Katherine; Wang, Hong; Hurst, Brett L; Siddharthan, Venkatraman; Van Wettere, Arnaud; Pilowsky, Paul M; Morrey, John D

2017-04-01

Neurological respiratory deficits are serious outcomes of West Nile virus (WNV) disease. WNV patients requiring intubation have a poor prognosis. We previously reported that WNV-infected rodents also appear to have respiratory deficits when assessed by whole-body plethysmography and diaphragmatic electromyography. The purpose of this study was to determine if the nature of the respiratory deficits in WNV-infected rodents is neurological and if deficits are due to a disorder of brainstem respiratory centers, cervical spinal cord (CSC) phrenic motor neuron (PMN) circuitry, or both. We recorded phrenic nerve (PN) activity and found that in WNV-infected mice, PN amplitude is reduced, corroborating a neurological basis for respiratory deficits. These results were associated with a reduction in CSC motor neuron number. We found no dramatic deficits, however, in brainstem-mediated breathing rhythm generation or responses to hypercapnia. PN frequency and pattern parameters were normal, and all PN parameters changed appropriately upon a CO 2 challenge. Histological analysis revealed generalized microglia activation, astrocyte reactivity, T cell and neutrophil infiltration, and mild histopathologic lesions in both the brainstem and CSC, but none of these were tightly correlated with PN function. Similar results in PN activity, brainstem function, motor neuron number, and histopathology were seen in WNV-infected hamsters, except that histopathologic lesions were more severe. Taken together, the results suggest that respiratory deficits in acute WNV infection are primarily due to a lower motor neuron disorder affecting PMNs and the PN rather than a brainstem disorder. Future efforts should focus on markers of neuronal dysfunction, axonal degeneration, and myelination.

Tonotopic alterations in inhibitory input to the medial nucleus of the trapezoid body in a mouse model of Fragile X syndrome.

PubMed

McCullagh, Elizabeth A; Salcedo, Ernesto; Huntsman, Molly M; Klug, Achim

2017-11-01

Hyperexcitability and the imbalance of excitation/inhibition are one of the leading causes of abnormal sensory processing in Fragile X syndrome (FXS). The precise timing and distribution of excitation and inhibition is crucial for auditory processing at the level of the auditory brainstem, which is responsible for sound localization ability. Sound localization is one of the sensory abilities disrupted by loss of the Fragile X Mental Retardation 1 (Fmr1) gene. Using triple immunofluorescence staining we tested whether there were alterations in the number and size of presynaptic structures for the three primary neurotransmitters (glutamate, glycine, and GABA) in the auditory brainstem of Fmr1 knockout mice. We found decreases in either glycinergic or GABAergic inhibition to the medial nucleus of the trapezoid body (MNTB) specific to the tonotopic location within the nucleus. MNTB is one of the primary inhibitory nuclei in the auditory brainstem and participates in the sound localization process with fast and well-timed inhibition. Thus, a decrease in inhibitory afferents to MNTB neurons should lead to greater inhibitory output to the projections from this nucleus. In contrast, we did not see any other significant alterations in balance of excitation/inhibition in any of the other auditory brainstem nuclei measured, suggesting that the alterations observed in the MNTB are both nucleus and frequency specific. We furthermore show that glycinergic inhibition may be an important contributor to imbalances in excitation and inhibition in FXS and that the auditory brainstem is a useful circuit for testing these imbalances. © 2017 Wiley Periodicals, Inc.

Hidden Hearing Loss and Computational Models of the Auditory Pathway: Predicting Speech Intelligibility Decline

DTIC Science & Technology

2016-11-28

of low spontaneous rate auditory nerve fibers (ANFs) and reduction of auditory brainstem response wave-I amplitudes. The goal of this research is...auditory nerve (AN) responses to speech stimuli under a variety of difficult listening conditions. The resulting cochlear neurogram, a spectrogram

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

Koyfman, Shlomo A.; Tendulkar, Rahul D.; Chao, Samuel T.

Purpose: To assess the imaging and clinical outcomes of patients with single brainstem metastases treated with stereotactic radiosurgery (SRS). Materials and Methods: We retrospectively reviewed the data from patients with single brainstem metastases treated with SRS. Locoregional control and survival were calculated using the Kaplan-Meier method. Prognostic factors were assessed using a Cox proportional hazards model. Results: Between 1997 and 2007, 43 patients with single brainstem metastases were treated with SRS. The median age at treatment was 59 years, the median Karnofsky performance status was 80, and the median follow-up was 5.3 months. The median dose was 15 Gy (range,more » 9.6-24), and the median conformality and heterogeneity index was 1.7 and 1.9, respectively. The median survival was 5.8 months from the procedure date. Of the 33 patient with post-treatment imaging available, a complete radiographic response was achieved in 2 (4.7%), a partial response in 8 (18.6%), and stable disease in 23 (53.5%). The 1-year actuarial rate of local control, distant brain control, and overall survival was 85%, 38.3%, and 31.5%, respectively. Of the 43 patients, 8 (19%) died within 2 months of undergoing SRS, and 15 (36%) died within 3 months. On multivariate analysis, greater performance status (hazard ratio [HR], 0.95, p = .004), score index for radiosurgery (HR, 0.7; p = .004), graded prognostic assessment score (HR, 0.48; p = .003), and smaller tumor volume (HR, 1.23, p = .002) were associated with improved survival. No Grade 3 or 4 toxicities were observed. Conclusion: The results of our study have shown that SRS is a safe and effective local therapy for patients with brainstem metastases.« less

Effect of pinching-evoked pain on jaw-stretch reflexes and exteroceptive suppression periods in healthy subjects.

PubMed

Biasiotta, A; Peddireddy, A; Wang, K; Romaniello, A; Frati, A; Svensson, P; Arendt-Nielsen, L

2007-10-01

To investigate the influence of conditioning cutaneous nociceptive inputs by a new "pinch" model on the jaw-stretch reflex and the exteroceptive suppression periods (ES1 and ES2) in jaw muscles. The jaw-stretch reflex was evoked with the use of a custom-made muscle stretcher and electrical stimuli were used to evoke an early and late exteroceptive suppression period (ES1 and ES2) in the jaw-closing muscles. Electromyographic (EMG) activity was recorded bilaterally from the masseter and temporalis muscles. These brainstem reflexes were recorded in 19 healthy men (28.8+/-1.1 years) during three different conditions: one painful clip applied to the earlobe; one painful clip applied to the nostril, and four painful clips applied simultaneously to the earlobe, nostril, eyebrow, and lower lip. Pain intensity induced by the application of the clips was scored continuously by the subjects on a 100mm visual analogue scale (VAS). The highest VAS pain scores were evoked by placement of four clips (79+/-0.5mm). There was no significant modulation of the jaw-stretch reflex (ANOVAs: P=0.929), the ES1 (P=0.298) or ES2 (P=0.082) in any of the three painful conditions. Intense and tonic cutaneous pain could be elicited by this new "pinch" pain model; however, there was no significant modulation on either excitatory or inhibitory brainstem reflex responses. The novel observation that high-intensity pinch stimuli applied to the craniofacial region fail to modulate two different brainstem reflexes is in contrast to other experimental pain studies documented facilitation of the jaw-stretch reflexes or inhibition of exteroceptive suppression periods. The clinical implication of the present findings is that only some craniofacial pain conditions could be expected to show perturbation of the brainstem reflex responses.

Sensitization of trigeminal brainstem pathways in a model for tear deficient dry eye

PubMed Central

Rahman, Mostafeezur; Okamoto, Keiichiro; Thompson, Randall; Katagiri, Ayano; Bereiter, David A.

2015-01-01

Abstract Chronic dry eye disease (DE) is associated with an unstable tear film and symptoms of ocular discomfort. The characteristics of symptoms suggest a key role for central neural processing; however, little is known about central neuroplasticity and DE. We used a model for tear deficient DE and assessed effects on eye blink behavior, orbicularis oculi muscle activity (OOemg), and trigeminal brainstem neural activity in male rats. Ocular-responsive neurons were recorded at the interpolaris/caudalis transition (Vi/Vc) and Vc/upper cervical cord (Vc/C1) regions under isoflurane, whereas OOemg activity was recorded under urethane. Spontaneous tear volume was reduced by ∼50% at 14 days after exorbital gland removal. Hypertonic saline–evoked eye blink behavior in awake rats was enhanced throughout the 14 days after surgery. Saline-evoked neural activity at the Vi/Vc transition and in superficial and deep laminae at the Vc/C1 region was greatly enhanced in DE rats. Neurons from DE rats classified as wide dynamic range displayed enlarged convergent periorbital receptive fields consistent with central sensitization. Saline-evoked OOemg activity was markedly enhanced in DE rats compared with controls. Synaptic blockade at the Vi/Vc transition or the Vc/C1 region greatly reduced hypertonic saline–evoked OOemg activity in DE and sham rats. These results indicated that persistent tear deficiency caused sensitization of ocular-responsive neurons at multiple regions of the caudal trigeminal brainstem and enhanced OOemg activity. Central sensitization of ocular-related brainstem circuits is a significant factor in DE and likely contributes to the apparent weak correlation between peripheral signs of tear dysfunction and symptoms of irritation. PMID:25734990

The effect of device use after sequential bilateral cochlear implantation in children: An electrophysiological approach.

PubMed

Sparreboom, Marloes; Beynon, Andy J; Snik, Ad F M; Mylanus, Emmanuel A M

2016-07-01

In many studies evaluating the effect of sequential bilateral cochlear implantation in congenitally deaf children, device use is not taken into account. In this study, however, device use was analyzed in relation to auditory brainstem maturation and speech recognition, which were measured in children with early-onset deafness, 5-6 years after bilateral cochlear implantation. We hypothesized that auditory brainstem maturation is mostly functionally driven by auditory stimulation and is therefore influenced by device use and not mainly by inter-implant delay. Twenty-one children participated and had inter-implant delays between 1.2 and 7.2 years. The electrically-evoked auditory brainstem response was measured for both implants separately. The difference in interaural wave V latency and speech recognition between both implants were used in the analyses. Device use was measured with a Likert scale. Results showed that the less the second device is used, the larger the difference in interaural wave V latencies is, which consequently leads to larger differences in interaural speech recognition. In children with early-onset deafness, after various periods of unilateral deprivation, full-time device use can lead to similar auditory brainstem responses and speech recognition between both ears. Therefore, device use should be considered as a relevant factor contributing to outcomes after sequential bilateral cochlear implantation. These results are indicative for a longer window between implantations in children with early-onset deafness to obtain symmetrical auditory pathway maturation than is mentioned in the literature. Results, however, must be interpreted as preliminary findings as actual device use with data logging was not yet available at the time of the study. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Optimizing Clinical Interpretation of Distortion Product Otoacoustic Emissions in Infants.

PubMed

Blankenship, Chelsea M; Hunter, Lisa L; Keefe, Douglas H; Feeney, M Patrick; Brown, David K; McCune, Annie; Fitzpatrick, Denis F; Lin, Li

2018-03-06

The purpose of this study was to analyze distortion product otoacoustic emission (DPOAE) level and signal to noise ratio in a group of infants from birth to 4 months of age to optimize prediction of hearing status. DPOAEs from infants with normal hearing (NH) and hearing loss (HL) were used to predict the presence of conductive HL (CHL), sensorineural HL (SNHL), and mixed HL (MHL). Wideband ambient absorbance was also measured and compared among the HL types. This is a prospective, longitudinal study of 279 infants with verified NH and HL, including conductive, sensorineural, and mixed types that were enrolled from a well-baby nursery and two neonatal intensive care units in Cincinnati, Ohio. At approximately 1 month of age, DPOAEs (1-8 kHz), wideband absorbance (0.25-8 kHz), and air and bone conduction diagnostic tone burst auditory brainstem response (0.5-4 kHz) thresholds were measured. Hearing status was verified at approximately 9 months of age with visual reinforcement audiometry (0.5-4 kHz). Auditory brainstem response air conduction thresholds were used to assign infants to an NH or HL group, and the efficacy of DPOAE data to classify ears as NH or HL was analyzed using receiver operating characteristic (ROC) curves. Two summary statistics of the ROC curve were calculated: the area under the ROC curve and the point of symmetry on the curve at which the sensitivity and specificity were equal. DPOAE level and signal to noise ratio cutoff values were defined at each frequency as the symmetry point on their respective ROC curve, and DPOAE results were combined across frequency in a multifrequency analysis to predict the presence of HL. Single-frequency test performance of DPOAEs was best at mid to high frequencies (3-8 kHz) with intermediate performance at 1.5 and 2 kHz and chance performance at 1 kHz. Infants with a conductive component to their HL (CHL and MHL combined) displayed significantly lower ambient absorbance values than the NH group. No differences in ambient absorbance were found between the NH and SNHL groups. Multifrequency analysis resulted in the best prediction of HL for the SNHL/MHL group with poorer sensitivity values when infants with CHL were included. Clinical interpretation of DPOAEs in infants can be improved by using age-appropriate normative ranges and optimized cutoff values. DPOAE interpretation is most predictive at higher F2 test frequencies in young infants (2-8 kHz) due to poor test performance at 1 to 1.5 kHz. Multifrequency rules can be used to improve sensitivity while balancing specificity. Last, a sensitive middle ear measure such as wideband absorbance should be included in the test battery to assess possibility of a conductive component to the HL.

Subcortical encoding of speech cues in children with attention deficit hyperactivity disorder.

PubMed

Jafari, Zahra; Malayeri, Saeed; Rostami, Reza

2015-02-01

There is little information about processing of nonspeech and speech stimuli at the subcortical level in individuals with attention deficit hyperactivity disorder (ADHD). The auditory brainstem response (ABR) provides information about the function of the auditory brainstem pathways. We aim to investigate the subcortical function in neural encoding of click and speech stimuli in children with ADHD. The subjects include 50 children with ADHD and 34 typically developing (TD) children between the ages of 8 and 12 years. Click ABR (cABR) and speech ABR (sABR) with 40 ms synthetic /da/ syllable stimulus were recorded. Latencies of cABR in waves of III and V and duration of V-Vn (P⩽0.027), and latencies of sABR in waves A, D, E, F and O and duration of V-A (P⩽0.034) were significantly longer in children with ADHD than in TD children. There were no apparent differences in components the sustained frequency following response (FFR). We conclude that children with ADHD have deficits in temporal neural encoding of both nonspeech and speech stimuli. There is a common dysfunction in the processing of click and speech stimuli at the brainstem level in children with suspected ADHD. Copyright © 2015. Published by Elsevier Ireland Ltd.

Noradrenergic Regulation of Central Amygdala in Aversive Pavlovian-to-Instrumental Transfer

PubMed Central

Soroeta, Jose M.

2017-01-01

Abstract The neural mechanisms through which a Pavlovian conditioned stimulus (CS) elicits innate defense responses are well understood. But a Pavlovian CS can also invigorate ongoing instrumental responding, as shown by studies of aversive Pavlovian-to-instrumental transfer (PIT). While the neural circuitry of appetitive PIT has been studied extensively, little is known about the brain mechanisms of aversive PIT. We recently showed the central amygdala (CeA) is essential for aversive PIT. In the current studies, using pharmacology and designer receptors in rodents, we demonstrate that noradrenergic (NE) activity negatively regulates PIT via brainstem locus coeruleus (LC) activity and LC projections to CeA. Our results provide evidence for a novel pathway through which response modulation occurs between brainstem neuromodulatory systems and CeA to invigorate adaptive behavior in the face of threat. PMID:29071299

Fos-defined activity in rat brainstem following centripetal acceleration.

PubMed

Kaufman, G D; Anderson, J H; Beitz, A J

1992-11-01

To identify rat brainstem nuclei involved in the initial, short-term response to a change in gravito-inertial force, adult Long-Evans rats were rotated in the horizontal plane for 90 min in complete darkness after they were eccentrically positioned off the axis of rotation (off-axis) causing a centripetal acceleration of 2 g. Neural activation was defined by the brainstem distribution of the c-fos primary response gene protein, Fos, using immunohistochemistry. The Fos labeling in off-axis animals was compared with that of control animals who were rotated on the axis of rotation (on-axis) with no centripetal acceleration, or who were restrained but not rotated. In the off-axis animals there was a significant labeling of neurons: in the inferior, medial, and y-group subnuclei of the vestibular complex; in subnuclei of the inferior olive, especially the dorsomedial cell column; in midbrain nuclei, including the interstitial nucleus of Cajal, nucleus of Darkschewitsch, Edinger-Westphal nucleus, and dorsolateral periaqueductal gray; in autonomic centers including the solitary nucleus, area postrema, and locus coeruleus; and in reticular nuclei including the lateral reticular nucleus and the lateral parabrachial nucleus. Also, there was greater Fos expression in the dorsomedial cell column, the principal inferior olive subnuclei, inferior vestibular nucleus, the dorsolateral central gray, and the locus coeruleus in animals who had their heads restrained compared to animals whose heads were not restrained. As one control, the vestibular neuroepithelium was destroyed by injecting sodium arsanilate into the middle ear, bilaterally. This resulted in a complete lack of Fos labeling in the vestibular nuclei and the inferior olive, and a significant reduction in labeling in other nuclei in the off-axis condition, indicating that these nuclei have a significant labyrinth-sensitive component to their Fos labeling. The data indicate that several novel brainstem regions, including the dorsomedial cell column of the inferior olive and the periaqueductal gray, as well as more traditional brainstem nuclei including vestibular and oculomotor related nuclei, respond to otolith activation during a sustained centripetal acceleration.

The Physiological Bases of Hidden Noise-Induced Hearing Loss: Protocol for a Functional Neuroimaging Study.

PubMed

Dewey, Rebecca Susan; Hall, Deborah A; Guest, Hannah; Prendergast, Garreth; Plack, Christopher J; Francis, Susan T

2018-03-09

Rodent studies indicate that noise exposure can cause permanent damage to synapses between inner hair cells and high-threshold auditory nerve fibers, without permanently altering threshold sensitivity. These demonstrations of what is commonly known as hidden hearing loss have been confirmed in several rodent species, but the implications for human hearing are unclear. Our Medical Research Council-funded program aims to address this unanswered question, by investigating functional consequences of the damage to the human peripheral and central auditory nervous system that results from cumulative lifetime noise exposure. Behavioral and neuroimaging techniques are being used in a series of parallel studies aimed at detecting hidden hearing loss in humans. The planned neuroimaging study aims to (1) identify central auditory biomarkers associated with hidden hearing loss; (2) investigate whether there are any additive contributions from tinnitus or diminished sound tolerance, which are often comorbid with hearing problems; and (3) explore the relation between subcortical functional magnetic resonance imaging (fMRI) measures and the auditory brainstem response (ABR). Individuals aged 25 to 40 years with pure tone hearing thresholds ≤20 dB hearing level over the range 500 Hz to 8 kHz and no contraindications for MRI or signs of ear disease will be recruited into the study. Lifetime noise exposure will be estimated using an in-depth structured interview. Auditory responses throughout the central auditory system will be recorded using ABR and fMRI. Analyses will focus predominantly on correlations between lifetime noise exposure and auditory response characteristics. This paper reports the study protocol. The funding was awarded in July 2013. Enrollment for the study described in this protocol commenced in February 2017 and was completed in December 2017. Results are expected in 2018. This challenging and comprehensive study will have the potential to impact diagnostic procedures for hidden hearing loss, enabling early identification of noise-induced auditory damage via the detection of changes in central auditory processing. Consequently, this will generate the opportunity to give personalized advice regarding provision of ear defense and monitoring of further damage, thus reducing the incidence of noise-induced hearing loss. ©Rebecca Susan Dewey, Deborah A Hall, Hannah Guest, Garreth Prendergast, Christopher J Plack, Susan T Francis. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 09.03.2018.

Antibodies to dendritic neuronal surface antigens in opsoclonus myoclonus ataxia syndrome

PubMed Central

Panzer, Jessica A.; Anand, Ronan; Dalmau, Josep; Lynch, David R.

2015-01-01

Opsoclonus myoclonus ataxia syndrome (OMAS) is an autoimmune disorder characterized by rapid, random, conjugate eye movements (opsoclonus), myoclonus, and ataxia. Given these symptoms, autoantibodies targeting the cerebellum or brainstem could mediate the disease or be markers of autoimmunity. In a subset of patients with OMAS, we identified such autoantibodies, which bind to non-synaptic puncta on the surface of live cultured cerebellar and brainstem neuronal dendrites. These findings implicate autoimmunity to a neuronal surface antigen in the pathophysiology of OMAS. Identification of the targeted antigen(s) could elucidate the mechanisms underlying OMAS and provide a biomarker for diagnosis and response to therapy. PMID:26298330

Successful Retreatment of a Child with a Refractory Brainstem Ganglioglioma with Vemurafenib.

PubMed

Aguilera, Dolly; Janss, Anna; Mazewski, Claire; Castellino, Robert Craig; Schniederjan, Matthew; Hayes, Laura; Brahma, Barunashish; Fogelgren, Lauren; MacDonald, Tobey J

2016-03-01

A child with brainstem ganglioglioma underwent subtotal resection and focal radiation. Magnetic resonance imaging confirmed tumor progression 6 months later. Another partial resection revealed viable BRAF V600E-positive residual tumor. Vemurafenib (660 mg/m(2) /dose) was administered twice daily, resulting in >70% tumor reduction with sustained clinical improvement for 1 year. Vemurafenib was then terminated, but significant tumor progression occurred 3 months later. Vemurafenib was restarted, resulting in partial response. Toxicities included Grade I pruritus and Grade II rash. Vemurafenib was effectively crushed and administered in solution via nasogastric tube. We demonstrate benefit from restarting vemurafenib therapy. © 2015 Wiley Periodicals, Inc.

Brainstem ischemic lesions on MRI in children with tuberculous meningitis: with diffusion weighted confirmation.

PubMed

van der Merwe, Dirk Johannes; Andronikou, Savvas; Van Toorn, Ronald; Pienaar, Manana

2009-08-01

The Western Cape in South Africa has one of the highest incidences of tuberculous meningitis (TBM) in the world. Despite therapy, the outcome in children with advanced TBM remains dismal. Magnetic resonance imaging (MRI) has been shown to be superior to computed tomography (CT) in demonstrating ischemia in TBM, especially of the brainstem. The objective of this study was to characterize brainstem lesions and association with clinical findings in children with TBM by using MRI. CT and multiplanar MRI scans were performed in 30 children with proven TBM. From this group, a subgroup with radiological ischemic changes of the brainstem were identified. Radiological findings in these patients were then correlated with severity of disease, motor deficit, and outcome after 6 months. Radiological brainstem abnormalities were identified in 14 out of 30 children. Thirty-eight brainstem lesions were confirmed to be ischemic. The severity of disease at presentation, degree of motor deficit, and developmental outcome after 6 months of the children with ischemic brainstem lesions was poorer compared to those children without brainstem involvement. However, both sensitivity and specificity of the MRI brainstem lesion detection for clinical outcome proved low. A significant percentage of children with TBM have ischemic brainstem lesions. These are poorly visualized on conventional CT. MRI scanning is more sensitive in detecting these lesions and localizing them. There appears to be some association between MRI-detected brainstem lesions and clinical outcome. The exact meaning of these lesions and their implication for the patient's management require further clarification.

Subacute Sclerosing Panencephalitis of the Brainstem as a Clinical Entity.

PubMed

Upadhyayula, Pavan S; Yang, Jason; Yue, John K; Ciacci, Joseph D

2017-11-07

Subacute sclerosing panencephalitis (SSPE) is a rare progressive neurological disorder of early adolescence caused by persistent infection of the measles virus, which remains prevalent worldwide despite an effective vaccine. SSPE is a devastating disease with a characteristic clinical course in subcortical white matter; however, atypical presentations of brainstem involvement may be seen in rare cases. This review summarizes reports to date on brainstem involvement in SSPE, including the clinical course of disease, neuroimaging presentations, and guidelines for treatment. A comprehensive literature search was performed for English-language publications with keywords "subacute sclerosing panencephalitis" and "brainstem" using the National Library of Medicine PubMed database (March 1981-September 2017). Eleven articles focusing on SSPE of the brainstem were included. Predominant brainstem involvement remains uncharacteristic of SSPE, which may lead to misdiagnosis and poor outcome. A number of case reports have demonstrated brainstem involvement associated with other intracranial lesions commonly presenting in later SSPE stages (III and IV). However, brainstem lesions can appear in all stages, independent of higher cortical structures. The varied clinical presentations complicate diagnosis from a neuroimaging perspective. SSPE of the brainstem is a rare but important clinical entity. It may present like canonical SSPE or with unique clinical features such as absence seizures and pronounced ataxia. While SSPE generally progresses to the brainstem, it can also begin with a primary focus of infection in the brainstem. Awareness of varied SSPE presentations can aid in early diagnosis as well as guide management and treatment.

Relating the variability of tone-burst otoacoustic emission and auditory brainstem response latencies to the underlying cochlear mechanics

NASA Astrophysics Data System (ADS)

Verhulst, Sarah; Shera, Christopher A.

2015-12-01

Forward and reverse cochlear latency and its relation to the frequency tuning of the auditory filters can be assessed using tone bursts (TBs). Otoacoustic emissions (TBOAEs) estimate the cochlear roundtrip time, while auditory brainstem responses (ABRs) to the same stimuli aim at measuring the auditory filter buildup time. Latency ratios are generally close to two and controversy exists about the relationship of this ratio to cochlear mechanics. We explored why the two methods provide different estimates of filter buildup time, and ratios with large inter-subject variability, using a time-domain model for OAEs and ABRs. We compared latencies for twenty models, in which all parameters but the cochlear irregularities responsible for reflection-source OAEs were identical, and found that TBOAE latencies were much more variable than ABR latencies. Multiple reflection-sources generated within the evoking stimulus bandwidth were found to shape the TBOAE envelope and complicate the interpretation of TBOAE latency and TBOAE/ABR ratios in terms of auditory filter tuning.

Difference of auditory brainstem responses by stimulating to round and oval window in animal experiments.

PubMed

Lee, Jyung Hyun; Park, Hyo Soon; Wei, Qun; Kim, Myoung Nam; Cho, Jin-Ho

2017-01-02

ABSTACT To ensure the safety and efficacy of implantable hearing aids, animal experiments are an essential developmental procedure, in particular, auditory brainstem responses (ABRs) can be used to verify the objective effectiveness of implantable hearing aids. This study measured and compared the ABRs generated when applying the same vibration stimuli to an oval window and round window. The ABRs were measured using a TDT system 3 (TDT, USA), while the vibration stimuli were applied to a round window and oval window in 4 guinea pigs using a piezo-electric transducer with a proper contact tip. A paired t-test was used to determine any differences between the ABR amplitudes when applying the stimulation to an oval window and round window. The paired t-test revealed a significant difference between the ABR amplitudes generated by the round and oval window stimulation (t = 10.079, α < .0001). Therefore, the results confirmed that the biological response to round window stimulation was not the same as that to oval window stimulation.

The H3.3 K27M mutation results in a poorer prognosis in brainstem gliomas than thalamic gliomas in adults.

PubMed

Feng, Jie; Hao, Shuyu; Pan, Changcun; Wang, Yu; Wu, Zhen; Zhang, Junting; Yan, Hai; Zhang, Liwei; Wan, Hong

2015-11-01

Brainstem and thalamic gliomas are rare, and they are poorly understood in adults. Genetic aberrations that occur in these tumors are still unknown. In this study, we investigated whether thalamic gliomas have different genetic aberrations and clinical outcomes compared with brainstem gliomas in adults. Forty-three glioma samples were selected, including 28 brainstem and 15 thalamic gliomas. The frequency of the K27M mutation in adult midline gliomas was 58.1%. High-grade gliomas in the thalamus were statistically significantly more numerous than brainstem gliomas. Patients with K27M mutant brainstem gliomas had a significantly shorter overall survival than patients with wild-type tumors (P = .020) by Cox regression after adjustment for other independent risk factors. However, there was no statistical tendency toward a poorer overall survival in thalamic gliomas containing the K27M mutation compared with wild-type tumors. The presence of the K27M mutation significantly corresponded with mutations in TP53 in thalamic gliomas. Interestingly, the K27M mutation was mutually exclusive with mutations in IDH1, which was detected only in brainstem gliomas. The microarray data identified 86 differentially expressed genes between brainstem and thalamic gliomas with the K27M mutation. The cyclin-dependent kinase 6 (CDK6) gene, which plays an important role in cancer pathways, was found to be differentially expressed between brainstem and thalamic gliomas with K27M mutations. Although the K27M mutation was frequently observed in adult brainstem and thalamic gliomas, this mutation tended to be associated with a poorer prognosis in brainstem gliomas but not in thalamic gliomas. Brainstem gliomas may present different genetic aberrations from thalamic gliomas. These differences may provide guidance for therapeutic decisions for the treatment of adult brainstem and thalamic gliomas, which may have different molecular targets. Copyright © 2015. Published by Elsevier Inc.

A direct approach for the design of chirp stimuli used for the recording of auditory brainstem responses

PubMed Central

Elberling, Claus; Don, Manuel

2010-01-01

A recent study evaluates auditory brainstem responses (ABRs) evoked by chirps of different durations (sweeping rates) [Elberling et al. (2010). J. Acoust. Soc. Am. 128, 215–223]. The study demonstrates that shorter chirps are most efficient at higher levels of stimulation whereas longer chirps are most efficient at lower levels. Mechanisms other than the traveling wave delay, in particular, upward spread of excitation and changes in cochlear-neural delay with level, are suggested to be responsible for these findings. As a consequence, delay models based on estimates of the traveling wave delay are insufficient for the design of chirp stimuli, and another delay model based on a direct approach is therefore proposed. The direct approach uses ABR-latencies from normal-hearing subjects in response to octave-band chirps over a wide range of levels. The octave-band chirps are constructed by decomposing a broad-band chirp, and constitute a subset of the chirp. The delay compensations of the proposed model are similar to those found in the previous experimental study, which thus verifies the results of the proposed model. PMID:21110591

Congenital brainstem disconnection associated with a syrinx of the brainstem.

PubMed

Barth, P G; de Vries, L S; Nikkels, P G J; Troost, D

2008-02-01

We report a case of congenital brainstem disconnection including the second detailed autopsy. A full-term newborn presented with irreversible apnoea and died on the fifth day. MRI revealed disconnection of the brainstem. The autopsy included a series of transverse sections of the mesencephalon, medulla oblongata and bridging tissue fragments. A fragile tube walled by mature brainstem tissue could be reconstructed. It enveloped a cylinder of fluid within the ventral pons extending to the mesencephalon and the lower brainstem. The aqueduct was patent and outside the lesion. The basilar artery was represented by a tiny median vessel. The ventral and lateral parts of the posterior brainstem were surrounded by heterotopic glial tissue. The olivary nucleus was absent and the cerebellar dentate nucleus was dysplastic. Considering the maturity of the remaining parts of the pons, the onset of structural decline is likely to be close to the time of birth. Probable causes are progressively insufficient perfusion through an hypoplastic basilar artery, and obstructed venous drainage through an abnormal glial barrier surrounding the posterior brainstem. The morphological findings can be characterized as a syrinx, known from disorders in which brainstem or spinal cord are damaged by a combination of mechanical and circulatory factors.

Brainstem auditory evoked potentials with the use of acoustic clicks and complex verbal sounds in young adults with learning disabilities.

PubMed

Kouni, Sophia N; Giannopoulos, Sotirios; Ziavra, Nausika; Koutsojannis, Constantinos

2013-01-01

Acoustic signals are transmitted through the external and middle ear mechanically to the cochlea where they are transduced into electrical impulse for further transmission via the auditory nerve. The auditory nerve encodes the acoustic sounds that are conveyed to the auditory brainstem. Multiple brainstem nuclei, the cochlea, the midbrain, the thalamus, and the cortex constitute the central auditory system. In clinical practice, auditory brainstem responses (ABRs) to simple stimuli such as click or tones are widely used. Recently, complex stimuli or complex auditory brain responses (cABRs), such as monosyllabic speech stimuli and music, are being used as a tool to study the brainstem processing of speech sounds. We have used the classic 'click' as well as, for the first time, the artificial successive complex stimuli 'ba', which constitutes the Greek word 'baba' corresponding to the English 'daddy'. Twenty young adults institutionally diagnosed as dyslexic (10 subjects) or light dyslexic (10 subjects) comprised the diseased group. Twenty sex-, age-, education-, hearing sensitivity-, and IQ-matched normal subjects comprised the control group. Measurements included the absolute latencies of waves I through V, the interpeak latencies elicited by the classical acoustic click, the negative peak latencies of A and C waves, as well as the interpeak latencies of A-C elicited by the verbal stimulus 'baba' created on a digital speech synthesizer. The absolute peak latencies of waves I, III, and V in response to monoaural rarefaction clicks as well as the interpeak latencies I-III, III-V, and I-V in the dyslexic subjects, although increased in comparison with normal subjects, did not reach the level of a significant difference (p<0.05). However, the absolute peak latencies of the negative wave C and the interpeak latencies of A-C elicited by verbal stimuli were found to be increased in the dyslexic group in comparison with the control group (p=0.0004 and p=0.045, respectively). In the subgroup consisting of 10 patients suffering from 'other learning disabilities' and who were characterized as with 'light' dyslexia according to dyslexia tests, no significant delays were found in peak latencies A and C and interpeak latencies A-C in comparison with the control group. Acoustic representation of a speech sound and, in particular, the disyllabic word 'baba' was found to be abnormal, as low as the auditory brainstem. Because ABRs mature in early life, this can help to identify subjects with acoustically based learning problems and apply early intervention, rehabilitation, and treatment. Further studies and more experience with more patients and pathological conditions such as plasticity of the auditory system, cochlear implants, hearing aids, presbycusis, or acoustic neuropathy are necessary until this type of testing is ready for clinical application. © 2013 Elsevier Inc. All rights reserved.

Insights into the central pathways involved in the emetic and behavioural responses to exendin-4 in the ferret.

PubMed

Lu, Zengbing; Yeung, Chi-Kong; Lin, Ge; Yew, David T W; Andrews, P L R; Rudd, John A

2017-01-01

GLP-1 receptor agonists are utilised for the treatment of Type-2 diabetes but can be associated with undesirable effects of nausea and vomiting. To investigate the role of GLP-1 receptors in mechanisms of emesis, behaviours indicative of nausea (BIN) and food intake in the ferret. Exendin-4 (10 and 30nmol, i.c.v.) induced emesis, inhibited food intake, and increased the frequency of BIN. Increases in c-Fos in the brainstem, midbrain and forebrain occurred in animals exhibiting emesis; no activation of the brainstem occurred in animals not vomiting. Exendin-4 (10nmol, i.c.v.) when preceded by i.c.v. saline (15μl), was not emetic but induced BIN and inhibited food intake; exendin (9-39) (100nmol) reduced BIN only. c-Fos showed that consistent with the absence of emesis in saline/exendin-4 treated animals there was no increase in c-Fos in the brainstem, but it increased in midbrain and forebrain nuclei. Excepting the amygdala, exendin (9-39) was without efffect on the increases in c-Fos. Analysis of c-Fos data showed a positive linear relationship between midbrain and forebrain areas irrespective of the occurrence of emesis induced by exendin-4. In contrast, brainstem and midbrain c-Fos levels were positively correlated, but only in animals with emesis. The brainstem is critical for exendin-4-induced emesis but suppression of food intake and BIN involves more rostral brain sites. Exendin-4-induced BIN and c-Fos activation of the amygdala are sensitive to exendin (9-39), whereas the suppression of food intake is not implicating separate control mechanisms for emesis and BIN. Copyright © 2016 Elsevier B.V. All rights reserved.

Resting-state functional magnetic resonance imaging of the subthalamic microlesion and stimulation effects in Parkinson's disease: Indications of a principal role of the brainstem

PubMed Central

Holiga, Štefan; Mueller, Karsten; Möller, Harald E.; Urgošík, Dušan; Růžička, Evžen; Schroeter, Matthias L.; Jech, Robert

2015-01-01

During implantation of deep-brain stimulation (DBS) electrodes in the target structure, neurosurgeons and neurologists commonly observe a “microlesion effect” (MLE), which occurs well before initiating subthalamic DBS. This phenomenon typically leads to a transitory improvement of motor symptoms of patients suffering from Parkinson's disease (PD). Mechanisms behind MLE remain poorly understood. In this work, we exploited the notion of ranking to assess spontaneous brain activity in PD patients examined by resting-state functional magnetic resonance imaging in response to penetration of DBS electrodes in the subthalamic nucleus. In particular, we employed a hypothesis-free method, eigenvector centrality (EC), to reveal motor-communication-hubs of the highest rank and their reorganization following the surgery; providing a unique opportunity to evaluate the direct impact of disrupting the PD motor circuitry in vivo without prior assumptions. Penetration of electrodes was associated with increased EC of functional connectivity in the brainstem. Changes in connectivity were quantitatively related to motor improvement, which further emphasizes the clinical importance of the functional integrity of the brainstem. Surprisingly, MLE and DBS were associated with anatomically different EC maps despite their similar clinical benefit on motor functions. The DBS solely caused an increase in connectivity of the left premotor region suggesting separate pathophysiological mechanisms of both interventions. While the DBS acts at the cortical level suggesting compensatory activation of less affected motor regions, the MLE affects more fundamental circuitry as the dysfunctional brainstem predominates in the beginning of PD. These findings invigorate the overlooked brainstem perspective in the understanding of PD and support the current trend towards its early diagnosis. PMID:26509113

Imaging of glial cell morphology, SOD1 distribution and elemental composition in the brainstem and hippocampus of the ALS hSOD1G93A rat.

PubMed

Stamenković, Stefan; Dučić, Tanja; Stamenković, Vera; Kranz, Alexander; Andjus, Pavle R

2017-08-15

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting motor and cognitive domains of the CNS. Mutations in the Cu,Zn-superoxide dismutase (SOD1) cause 20% of familial ALS and provoke formation of intracellular aggregates and copper and zinc unbinding, leading to glial activation and neurodegeneration. Therefore, we investigated glial cell morphology, intracellular SOD1 distribution, and elemental composition in the brainstem and hippocampus of the hSOD1 G93A transgenic rat model of ALS. Immunostaining for astrocytes, microglia and SOD1 revealed glial proliferation and progressive tissue accumulation of SOD1 in both brain regions of ALS rats starting already at the presymptomatic stage. Glial cell morphology analysis in the brainstem of ALS rats revealed astrocyte activation occurring before disease symptoms onset, followed by activation of microglia. Hippocampal ALS astrocytes exhibited an identical reactive profile, while microglial morphology was unchanged. Additionally, ALS brainstem astrocytes demonstrated progressive SOD1 accumulation in the cell body and processes, while microglial SOD1 levels were reduced and its distribution limited to distal cell processes. In the hippocampus both glial cell types exhibited SOD1 accumulation in the cell body. X-ray fluorescence imaging revealed decreased P and increased Ca, Cl, K, Ni, Cu and Zn in the brainstem, and higher levels of Cl, Ni and Cu, but lower levels of Zn in the hippocampus of symptomatic ALS rats. These results bring new insights into the glial response during disease development and progression in motor as well as in non-motor CNS structures, and indicate disturbed tissue elemental homeostasis as a prominent hallmark of disease pathology. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Resting-state functional magnetic resonance imaging of the subthalamic microlesion and stimulation effects in Parkinson's disease: Indications of a principal role of the brainstem.

PubMed

Holiga, Štefan; Mueller, Karsten; Möller, Harald E; Urgošík, Dušan; Růžička, Evžen; Schroeter, Matthias L; Jech, Robert

2015-01-01

During implantation of deep-brain stimulation (DBS) electrodes in the target structure, neurosurgeons and neurologists commonly observe a "microlesion effect" (MLE), which occurs well before initiating subthalamic DBS. This phenomenon typically leads to a transitory improvement of motor symptoms of patients suffering from Parkinson's disease (PD). Mechanisms behind MLE remain poorly understood. In this work, we exploited the notion of ranking to assess spontaneous brain activity in PD patients examined by resting-state functional magnetic resonance imaging in response to penetration of DBS electrodes in the subthalamic nucleus. In particular, we employed a hypothesis-free method, eigenvector centrality (EC), to reveal motor-communication-hubs of the highest rank and their reorganization following the surgery; providing a unique opportunity to evaluate the direct impact of disrupting the PD motor circuitry in vivo without prior assumptions. Penetration of electrodes was associated with increased EC of functional connectivity in the brainstem. Changes in connectivity were quantitatively related to motor improvement, which further emphasizes the clinical importance of the functional integrity of the brainstem. Surprisingly, MLE and DBS were associated with anatomically different EC maps despite their similar clinical benefit on motor functions. The DBS solely caused an increase in connectivity of the left premotor region suggesting separate pathophysiological mechanisms of both interventions. While the DBS acts at the cortical level suggesting compensatory activation of less affected motor regions, the MLE affects more fundamental circuitry as the dysfunctional brainstem predominates in the beginning of PD. These findings invigorate the overlooked brainstem perspective in the understanding of PD and support the current trend towards its early diagnosis.

Hemodynamic Signal Changes Accompanying Execution and Imagery of Swallowing in Patients with Dysphagia: A Multiple Single-Case Near-Infrared Spectroscopy Study

PubMed Central

Kober, Silvia Erika; Bauernfeind, Günther; Woller, Carina; Sampl, Magdalena; Grieshofer, Peter; Neuper, Christa; Wood, Guilherme

2015-01-01

In the present multiple case study, we examined hemodynamic changes in the brain in response to motor execution (ME) and motor imagery (MI) of swallowing in dysphagia patients compared to healthy matched controls using near-infrared spectroscopy (NIRS). Two stroke patients with cerebral lesions in the right hemisphere, two stroke patients with lesions in the brainstem, and two neurologically healthy control subjects actively swallowed saliva (ME) and mentally imagined to swallow saliva (MI) in a randomized order while changes in concentration of oxygenated hemoglobin (oxy-Hb) and deoxygenated hemoglobin (deoxy-Hb) were assessed. In line with recent findings in healthy young adults, MI and ME of swallowing led to the strongest NIRS signal change in the inferior frontal gyrus in stroke patients as well as in healthy elderly. We found differences in the topographical distribution and time course of the hemodynamic response in dependence on lesion location. Dysphagia patients with lesions in the brainstem showed bilateral hemodynamic signal changes in the inferior frontal gyrus during active swallowing comparable to healthy controls. In contrast, dysphagia patients with cerebral lesions in the right hemisphere showed more unilateral activation patterns during swallowing. Furthermore, patients with cerebral lesions showed a prolonged time course of the hemodynamic response during MI and ME of swallowing compared to healthy controls and patients with brainstem lesions. Brain activation patterns associated with ME and MI of swallowing were largely comparable, especially for changes in deoxy-Hb. Hence, the present results provide new evidence regarding timing and topographical distribution of the hemodynamic response during ME and MI of swallowing in dysphagia patients and may have practical impact on future dysphagia treatment. PMID:26217298

Deciphering the Neural Control of Sympathetic Nerve Activity: Status Report and Directions for Future Research.

PubMed

Barman, Susan M; Yates, Bill J

2017-01-01

Sympathetic nerve activity (SNA) contributes appreciably to the control of physiological function, such that pathological alterations in SNA can lead to a variety of diseases. The goal of this review is to discuss the characteristics of SNA, briefly review the methodology that has been used to assess SNA and its control, and to describe the essential role of neurophysiological studies in conscious animals to provide additional insights into the regulation of SNA. Studies in both humans and animals have shown that SNA is rhythmic or organized into bursts whose frequency varies depending on experimental conditions and the species. These rhythms are generated by brainstem neurons, and conveyed to sympathetic preganglionic neurons through several pathways, including those emanating from the rostral ventrolateral medulla. Although rhythmic SNA is present in decerebrate animals (indicating that neurons in the brainstem and spinal cord are adequate to generate this activity), there is considerable evidence that a variety of supratentorial structures including the insular and prefrontal cortices, amygdala, and hypothalamic subnuclei provide inputs to the brainstem regions that regulate SNA. It is also known that the characteristics of SNA are altered during stress and particular behaviors such as the defense response and exercise. While it is a certainty that supratentorial structures contribute to changes in SNA during these behaviors, the neural underpinnings of the responses are yet to be established. Understanding how SNA is modified during affective responses and particular behaviors will require neurophysiological studies in awake, behaving animals, including those that entail recording activity from neurons that generate SNA. Recent studies have shown that responses of neurons in the central nervous system to most sensory inputs are context-specific. Future neurophysiological studies in conscious animals should also ascertain whether this general rule also applies to sensory signals that modify SNA.

Benign paroxysmal vertigo of childhood: diagnostic value of vestibular test and high stimulus rate auditory brainstem response test.

PubMed

Zhang, Daogong; Fan, Zhaomin; Han, Yuechen; Wang, Mingming; Xu, Lei; Luo, Jianfen; Ai, Yu; Wang, Haibo

2012-01-01

To investigate the diagnostic value of vestibular test and high stimulus rate auditory brainstem response (ABR) test and the possible mechanism responsible for benign paroxysmal vertigo of childhood (BPVC). Data of 56 patients with BPVC in vertigo clinic of our hospital from May 2007 to September 2008 were retrospectively analyzed in this study. Patients with BPVC were tested with pure tone audiometry, high stimulus rate auditory brainstem response test (ABR), transcranial Doppler sonography (TCD), bithermal caloric test, and VEMP. The results of the hearing and vestibular function test were compared and analyzed. There were 56 patients with BPVC, including 32 men, 24 women, aged 3-12 years old, with an average of 6.5 years. Among 56 cases of BPVC patients, the results of pure tone audiometry were all normal. High stimulus rate ABR was abnormal in 66.1% (37/56) of cases. TCD showed 57.1% abnormality in 56 cases, including faster flow rate in 28 cases and slower flow rate in 4 cases. High stimulus rate ABR and TCD were both abnormal in 48.2% (27/56) of cases. Bithermal caloric test was abnormal in 14.3% (8/56) of cases. VEMP showed 32.1% abnormality, including amplitude abnormality in 16 cases and latency abnormality in 2 cases. The abnormal rate of VEMP was much higher than that of caloric test. Vascular mechanisms might be involved in the pathogenesis of BPVC and there is strong evidence for close relationship between BPVC and migraine. High stimulus rate ABR is helpful in the diagnosis of BPVC. The inferior vestibular pathway is much more impaired than the superior vestibular pathway in BPVC. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Cardiorespiratory concerns shape brain responses during automatic panic-related scene processing in patients with panic disorder

PubMed Central

Feldker, Katharina; Heitmann, Carina Yvonne; Neumeister, Paula; Brinkmann, Leonie; Bruchmann, Maximillan; Zwitserlood, Pienie; Straube, Thomas

2018-01-01

Background Increased automatic processing of threat-related stimuli has been proposed as a key element in panic disorder. Little is known about the neural basis of automatic processing, in particular to task-irrelevant, panic-related, ecologically valid stimuli, or about the association between brain activation and symptomatology in patients with panic disorder. Methods The present event-related functional MRI (fMRI) study compared brain responses to task-irrelevant, panic-related and neutral visual stimuli in medication-free patients with panic disorder and healthy controls. Panic-related and neutral scenes were presented while participants performed a spatially non-overlapping bar orientation task. Correlation analyses investigated the association between brain responses and panic-related aspects of symptomatology, measured using the Anxiety Sensitivity Index (ASI). Results We included 26 patients with panic disorder and 26 heatlhy controls in our analysis. Compared with controls, patients with panic disorder showed elevated activation in the amygdala, brainstem, thalamus, insula, anterior cingulate cortex and midcingulate cortex in response to panic-related versus neutral task-irrelevant stimuli. Furthermore, fear of cardiovascular symptoms (a subcomponent of the ASI) was associated with insula activation, whereas fear of respiratory symptoms was associated with brainstem hyperactivation in patients with panic disorder. Limitations The additional implementation of measures of autonomic activation, such as pupil diameter, heart rate, or electrodermal activity, would have been informative during the fMRI scan as well as during the rating procedure. Conclusion Results reveal a neural network involved in the processing of panic-related distractor stimuli in patients with panic disorder and suggest an automatic weighting of panic-related information depending on the magnitude of cardiovascular and respiratory symptoms. Insula and brainstem activations show function-related associations with specific components of panic symptomatology. PMID:29252163

Cardiorespiratory concerns shape brain responses during automatic panic-related scene processing in patients with panic disorder.

PubMed

Feldker, Katharina; Heitmann, Carina Yvonne; Neumeister, Paula; Brinkmann, Leonie; Bruchmann, Maximillan; Zwitserlood, Pienie; Straube, Thomas

2018-01-01

Increased automatic processing of threat-related stimuli has been proposed as a key element in panic disorder. Little is known about the neural basis of automatic processing, in particular to task-irrelevant, panic-related, ecologically valid stimuli, or about the association between brain activation and symptomatology in patients with panic disorder. The present event-related functional MRI (fMRI) study compared brain responses to task-irrelevant, panic-related and neutral visual stimuli in medication-free patients with panic disorder and healthy controls. Panic-related and neutral scenes were presented while participants performed a spatially nonoverlapping bar orientation task. Correlation analyses investigated the association between brain responses and panic-related aspects of symptomatology, measured using the Anxiety Sensitivity Index (ASI). We included 26 patients with panic disorder and 26 heatlhy controls in our analysis. Compared with controls, patients with panic disorder showed elevated activation in the amygdala, brainstem, thalamus, insula, anterior cingulate cortex and midcingulate cortex in response to panic-related versus neutral task-irrelevant stimuli. Furthermore, fear of cardiovascular symptoms (a subcomponent of the ASI) was associated with insula activation, whereas fear of respiratory symptoms was associated with brainstem hyperactivation in patients with panic disorder. The additional implementation of measures of autonomic activation, such as pupil diameter, heart rate, or electrodermal activity, would have been informative during the fMRI scan as well as during the rating procedure. Results reveal a neural network involved in the processing of panic-related distractor stimuli in patients with panic disorder and suggest an automatic weighting of panic-related information depending on the magnitude of cardiovascular and respiratory symptoms. Insula and brainstem activations show function-related associations with specific components of panic symptomatology.

Cardiorespiratory concerns shape brain responses during automatic panic-related scene processing in patients with panic disorder.

PubMed

Feldker, Katharina; Heitmann, Carina Yvonne; Neumeister, Paula; Brinkmann, Leonie; Bruchmann, Maximillan; Zwitserlood, Pienie; Straube, Thomas

2017-09-26

Increased automatic processing of threat-related stimuli has been proposed as a key element in panic disorder. Little is known about the neural basis of automatic processing, in particular to task-irrelevant, panic-related, ecologically valid stimuli, or about the association between brain activation and symptomatology in patients with panic disorder. The present event-related fMRI study compared brain responses to task-irrelevant, panic-related and neutral visual stimuli in medication-free patients with panic disorder and healthy controls. Panic-related and neutral scenes were presented while participants performed a spatially nonoverlapping bar orientation task. Correlation analyses investigated the association between brain responses and panic-related aspects of symptomatology, measured using the Anxiety Sensitivity Index (ASI). We included 26 patients with panic disorder and 26 heatlhy controls in our analysis. Compared with controls, patients with panic disorder showed elevated activation in the amygdala, brainstem, thalamus, insula, anterior cingulate cortex and midcingulate cortex in response to panic-related versus neutral task-irrelevant stimuli. Furthermore, fear of cardiovascular symptoms (a subcomponent of the ASI) was associated with insula activation, whereas fear of respiratory symptoms was associated with brainstem hyperactivation in patients with panic disorder. The additional implementation of measures of autonomic activation, such as pupil diameter, heart rate, or electrodermal activity, would have been informative during the fMRI scan as well as during the rating procedure. Results reveal a neural network involved in the processing of panic-related distractor stimuli in patients with panic disorder and suggest an automatic weighting of panic-related information depending on the magnitude of cardiovascular and respiratory symptoms. Insula and brainstem activations show function-related associations with specific components of panic symptomatology.

Physiological Characterization of Vestibular Efferent Brainstem Neurons Using a Transgenic Mouse Model

PubMed Central

Leijon, Sara; Magnusson, Anna K.

2014-01-01

The functional role of efferent innervation of the vestibular end-organs in the inner ear remains elusive. This study provides the first physiological characterization of the cholinergic vestibular efferent (VE) neurons in the brainstem by utilizing a transgenic mouse model, expressing eGFP under a choline-acetyltransferase (ChAT)-locus spanning promoter in combination with targeted patch clamp recordings. The intrinsic electrical properties of the eGFP-positive VE neurons were compared to the properties of the lateral olivocochlear (LOC) brainstem neurons, which gives rise to efferent innervation of the cochlea. Both VE and the LOC neurons were marked by their negative resting membrane potential <−75 mV and their passive responses in the hyperpolarizing range. In contrast, the response properties of VE and LOC neurons differed significantly in the depolarizing range. When injected with positive currents, VE neurons fired action potentials faithfully to the onset of depolarization followed by sparse firing with long inter-spike intervals. This response gave rise to a low response gain. The LOC neurons, conversely, responded with a characteristic delayed tonic firing upon depolarizing stimuli, giving rise to higher response gain than the VE neurons. Depolarization triggered large TEA insensitive outward currents with fast inactivation kinetics, indicating A-type potassium currents, in both the inner ear-projecting neuronal types. Immunohistochemistry confirmed expression of Kv4.3 and 4.2 ion channel subunits in both the VE and LOC neurons. The difference in spiking responses to depolarization is related to a two-fold impact of these transient outward currents on somatic integration in the LOC neurons compared to in VE neurons. It is speculated that the physiological properties of the VE neurons might be compatible with a wide-spread control over motion and gravity sensation in the inner ear, providing likewise feed-back amplification of abrupt and strong phasic signals from the semi-circular canals and of tonic signals from the gravito-sensitive macular organs. PMID:24867596

Auditory brainstem response as a diagnostic tool for patients suffering from schizophrenia, attention deficit hyperactivity disorder, and bipolar disorder: protocol.

PubMed

Wahlström, Viktor; Åhlander, Fredrik; Wynn, Rolf

2015-02-12

Psychiatric disorders, such as schizophrenia, attention deficit hyperactivity disorder (ADHD), and bipolar disorder, may sometimes be difficult to diagnose. There is a great need for a valid and reliable diagnostic tool to aid clinicians in arriving at the diagnoses in a timely and accurate manner. Prior studies have suggested that patients suffering from schizophrenia and ADHD may process certain sound stimuli in the brainstem in an unusual manner. When these patient groups have been examined with the electrophysiological method of brainstem audiometry, some studies have found illness-specific aberrations. Such aberrations may also exist for patients suffering from bipolar disorder. In this study, we will examine whether the method of brainstem audiometry can be used as a diagnostic tool for patients suffering from schizophrenia, ADHD, and bipolar disorder. The method includes three steps: (1) auditory stimulation with specific sound stimuli, (2) simultaneous measurement of brainstem activity, and (3) automated interpretation of the resulting brain stem audiograms with data-based signal analysis. We will compare three groups of 12 individuals with confirmed diagnoses of schizophrenia, ADHD, or bipolar disorder with 12 healthy subjects under blinded conditions for a total of 48 participants. The extent to which the method can be used to reach the correct diagnosis will be investigated. The project is now in a recruiting phase. When all patients and controls have been recruited and the measurements have been performed, the data will be analyzed according to a previously arranged algorithm. We expect the recruiting phase and measurements to be completed in early 2015, the analyses to be performed in mid-2015, and the results of the study to be published in early 2016. If the results support previous findings, this will lend strength to the idea that brainstem audiometry can offer objective diagnostic support for patients suffering from schizophrenia, ADHD, and bipolar disorder. A positive result from the study could imply that brainstem audiometry could become an important supportive tool for clinicians in their efforts to diagnose patients with these disorders in a timely and accurate manner. ClinicalTrials.gov NCT01629355; https://clinicaltrials.gov/ct2/show/NCT01629355 (Archived by WebCite at http://www.webcitation.org/6VBfTwx5H).

An Analysis of The Parameters Used In Speech ABR Assessment Protocols.

PubMed

Sanfins, Milaine D; Hatzopoulos, Stavros; Donadon, Caroline; Diniz, Thais A; Borges, Leticia R; Skarzynski, Piotr H; Colella-Santos, Maria Francisca

2018-04-01

The aim of this study was to assess the parameters of choice, such as duration, intensity, rate, polarity, number of sweeps, window length, stimulated ear, fundamental frequency, first formant, and second formant, from previously published speech ABR studies. To identify candidate articles, five databases were assessed using the following keyword descriptors: speech ABR, ABR-speech, speech auditory brainstem response, auditory evoked potential to speech, speech-evoked brainstem response, and complex sounds. The search identified 1288 articles published between 2005 and 2015. After filtering the total number of papers according to the inclusion and exclusion criteria, 21 studies were selected. Analyzing the protocol details used in 21 studies suggested that there is no consensus to date on a speech-ABR protocol and that the parameters of analysis used are quite variable between studies. This inhibits the wider generalization and extrapolation of data across languages and studies.

Magnetic resonance imaging differential diagnosis of brainstem lesions in children

PubMed Central

Quattrocchi, Carlo Cosimo; Errante, Yuri; Rossi Espagnet, Maria Camilla; Galassi, Stefania; Della Sala, Sabino Walter; Bernardi, Bruno; Fariello, Giuseppe; Longo, Daniela

2016-01-01

Differential diagnosis of brainstem lesions, either isolated or in association with cerebellar and supra-tentorial lesions, can be challenging. Knowledge of the structural organization is crucial for the differential diagnosis and establishment of prognosis of pathologies with involvement of the brainstem. Familiarity with the location of the lesions in the brainstem is essential, especially in the pediatric population. Magnetic resonance imaging (MRI) is the most sensitive and specific imaging technique for diagnosing disorders of the posterior fossa and, particularly, the brainstem. High magnetic static field MRI allows detailed visualization of the morphology, signal intensity and metabolic content of the brainstem nuclei, together with visualization of the normal development and myelination. In this pictorial essay we review the brainstem pathology in pediatric patients and consider the MR imaging patterns that may help the radiologist to differentiate among vascular, toxico-metabolic, infective-inflammatory, degenerative and neoplastic processes. Helpful MR tips can guide the differential diagnosis: These include the location and morphology of lesions, the brainstem vascularization territories, gray and white matter distribution and tissue selective vulnerability. PMID:26834941

[Results from ten years newborn hearing screening in a secondary hospital].

PubMed

Sequi Canet, José Miguel; Sala Langa, Maria José; Collar Del Castillo, José Ignacio

2016-10-01

A critical analysis is performed on the results of a newborn hearing screening program in a regional hospital. Screening results from 14,247 newborns in our maternity ward from 2002 to 2013. Two step recordings of bilateral otoacoustic emissions (initial and repeat, if failed, at about one month of life). Assessment by clinical brainstem responses. The first step was performed on 14,015 newborns (98.3% of the total) reaching the screening objective. The first step pass figures were 93.7%, which implies a good pass rate with a few patients to repeat. The second step is also good because it has a pass rate of 88.9% of newborns examined (only 0.63% of initial group needed brainstem responses assessment), but 10.6% were lost to follow up, and that is a major problem. In newborns, scheduled for brainstem responses, the loss to follow-up is worse, with a figure of 29.5%, despite the high accuracy of this test given that 69.4% of those assessed showed hearing loss. This figure represents a 0.31% of the initial group, and is a similar to that published for congenital hearing loss. Including patients that were lost to follow up this figure could be greater. Newborn hearing screening is useful but needs stronger control to avoid the follow up loss. In order to achieve this, it is crucial to have a good database and a screening coordinator. Copyright © 2015 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Short GSM mobile phone exposure does not alter human auditory brainstem response.

PubMed

Stefanics, Gábor; Kellényi, Lóránd; Molnár, Ferenc; Kubinyi, Györgyi; Thuróczy, György; Hernádi, István

2007-11-12

There are about 1.6 billion GSM cellular phones in use throughout the world today. Numerous papers have reported various biological effects in humans exposed to electromagnetic fields emitted by mobile phones. The aim of the present study was to advance our understanding of potential adverse effects of the GSM mobile phones on the human hearing system. Auditory Brainstem Response (ABR) was recorded with three non-polarizing Ag-AgCl scalp electrodes in thirty young and healthy volunteers (age 18-26 years) with normal hearing. ABR data were collected before, and immediately after a 10 minute exposure to 900 MHz pulsed electromagnetic field (EMF) emitted by a commercial Nokia 6310 mobile phone. Fifteen subjects were exposed to genuine EMF and fifteen to sham EMF in a double blind and counterbalanced order. Possible effects of irradiation was analyzed by comparing the latency of ABR waves I, III and V before and after genuine/sham EMF exposure. Paired sample t-test was conducted for statistical analysis. Results revealed no significant differences in the latency of ABR waves I, III and V before and after 10 minutes of genuine/sham EMF exposure. The present results suggest that, in our experimental conditions, a single 10 minute exposure of 900 MHz EMF emitted by a commercial mobile phone does not produce measurable immediate effects in the latency of auditory brainstem waves I, III and V.

Auditory Brainstem Circuits That Mediate the Middle Ear Muscle Reflex

PubMed Central

Mukerji, Sudeep; Windsor, Alanna Marie; Lee, Daniel J.

2010-01-01

The middle ear muscle (MEM) reflex is one of two major descending systems to the auditory periphery. There are two middle ear muscles (MEMs): the stapedius and the tensor tympani. In man, the stapedius contracts in response to intense low frequency acoustic stimuli, exerting forces perpendicular to the stapes superstructure, increasing middle ear impedance and attenuating the intensity of sound energy reaching the inner ear (cochlea). The tensor tympani is believed to contract in response to self-generated noise (chewing, swallowing) and nonauditory stimuli. The MEM reflex pathways begin with sound presented to the ear. Transduction of sound occurs in the cochlea, resulting in an action potential that is transmitted along the auditory nerve to the cochlear nucleus in the brainstem (the first relay station for all ascending sound information originating in the ear). Unknown interneurons in the ventral cochlear nucleus project either directly or indirectly to MEM motoneurons located elsewhere in the brainstem. Motoneurons provide efferent innervation to the MEMs. Although the ascending and descending limbs of these reflex pathways have been well characterized, the identity of the reflex interneurons is not known, as are the source of modulatory inputs to these pathways. The aim of this article is to (a) provide an overview of MEM reflex anatomy and physiology, (b) present new data on MEM reflex anatomy and physiology from our laboratory and others, and (c) describe the clinical implications of our research. PMID:20870664

Subacute Sclerosing Panencephalitis of the Brainstem as a Clinical Entity

PubMed Central

Yang, Jason; Ciacci, Joseph D.

2017-01-01

Subacute sclerosing panencephalitis (SSPE) is a rare progressive neurological disorder of early adolescence caused by persistent infection of the measles virus, which remains prevalent worldwide despite an effective vaccine. SSPE is a devastating disease with a characteristic clinical course in subcortical white matter; however, atypical presentations of brainstem involvement may be seen in rare cases. This review summarizes reports to date on brainstem involvement in SSPE, including the clinical course of disease, neuroimaging presentations, and guidelines for treatment. A comprehensive literature search was performed for English-language publications with keywords “subacute sclerosing panencephalitis” and “brainstem” using the National Library of Medicine PubMed database (March 1981–September 2017). Eleven articles focusing on SSPE of the brainstem were included. Predominant brainstem involvement remains uncharacteristic of SSPE, which may lead to misdiagnosis and poor outcome. A number of case reports have demonstrated brainstem involvement associated with other intracranial lesions commonly presenting in later SSPE stages (III and IV). However, brainstem lesions can appear in all stages, independent of higher cortical structures. The varied clinical presentations complicate diagnosis from a neuroimaging perspective. SSPE of the brainstem is a rare but important clinical entity. It may present like canonical SSPE or with unique clinical features such as absence seizures and pronounced ataxia. While SSPE generally progresses to the brainstem, it can also begin with a primary focus of infection in the brainstem. Awareness of varied SSPE presentations can aid in early diagnosis as well as guide management and treatment. PMID:29112137

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

Giantsoudi, D; Adams, J; MacDonald, S

Purpose: In proton radiation therapy of posterior fossa tumors, to spare other sensitive structures, the preferred beam geometry results in placing the treatment field distal edge within or just beyond the brainstem, including in at least partially in the treatment volume. Concerns for brainstem toxicity are increased and a controversy exists as to weather the beam’s distal edge should be placed within the brainstem or beyond it, to avoid elevated linear energy transfer (LET) and relative biological effectiveness (RBE) within the brainstem. The dosimetric efficacy of these techniques was examined, accounting for LET- and dose-dependent variable RBE distributions. Methods: Threemore » treatment planning techniques were applied in six ependymoma cases: (a) three-field dose-sparing, with beams’ distal edge within the brainstem; (b) three-field LET-sparing, using same beam directions as (a) but extended field ranges beyond the brainstem; (c) two-posterior-oblique LET-sparing, with extended ranges as (b). Monte Carlo calculated dose, LET and RBE-weighted dose distributions were compared. Results: Lower LET values in the brainstem were accompanied by higher median dose: 53.7 Gy[RBE] and 54.3 Gy[RBE] for techniques (b) and (c) versus 52.1 Gy[RBE] for (a). Accounting for variable RBE, a 15% increase of the brainstem volume receiving at least 60 Gy[RBE] was observed for technique (c) versus (a). Maximum variable-RBE-weighted brainstem dose was comparable for all techniques. Conclusion: Extending the treatment beam range beyond the brainstem, significantly increased its volume receiving high dose radiation, even when accounting for the decreased LET values. The dosimetric benefits of techniques limiting the brainstem dose may outweigh the impact of LET reduction achieved through this technique, especially since clinical consequences of increased LET at the end of range have not been proven yet.« less

Administration of IL-1β to the 4th ventricle causes anorexia that is blocked by agouti-related peptide and that coincides with activation of tyrosine-hydroxylase neurons in the nucleus of the solitary tract

PubMed Central

DeBoer, Mark D.; Scarlett, Jarrad M.; Levasseur, Peter R.; Grant, Wilmon F.; Marks, Daniel L.

2010-01-01

Inflammation-associated cachexia is associated with multiple chronic diseases and involves activation of appetite regulating centers in the arcuate nucleus of the hypothalamus (ARH). The nucleus of the solitary tract (NTS) in the brainstem has also been implicated as an important nucleus involved in appetite regulation. We set out to determine whether the NTS may be involved in inflammation-associated anorexia by injecting IL-1β into the 4th ventricle and assessing food intake and NTS neuronal activation. Injection of IL-1β produced a decrease in food intake at 3 and 12 h after injection which was ameliorated at the 12 h time point by a sub-threshold dose of agouti-related peptide (AgRP). Investigation into neuron types in the NTS revealed that IL-1β injection was associated with an increase in c-Fos activity in NTS neurons expressing tyrosine hydroxylase (TH). Additionally, injection of IL-1β into the 4th ventricle did not produce c-Fos activation of neurons expressing pro-opiomelanocortin (POMC) in the ARH, cells known to be involved in producing anorexia in response to systemic inflammation. Double-label in situ hybridization revealed that TH neurons did not express IL-1 receptor I (IL1-RI) transcript, demonstrating that c-Fos activation of TH neurons in this setting was not via direct stimulation of IL-1β on TH neurons themselves. We conclude that IL-1β injection into the 4th ventricle produces anorexia and is accompanied by an increase in activation in TH neurons in the NTS. This provides evidence that the brainstem may be an important mediator of anorexia in the setting of inflammation. PMID:19028534

Impact of Morphometry, Myelinization and Synaptic Current Strength on Spike Conduction in Human and Cat Spiral Ganglion Neurons

PubMed Central

Rattay, Frank; Potrusil, Thomas; Wenger, Cornelia; Wise, Andrew K.; Glueckert, Rudolf; Schrott-Fischer, Anneliese

2013-01-01

Background Our knowledge about the neural code in the auditory nerve is based to a large extent on experiments on cats. Several anatomical differences between auditory neurons in human and cat are expected to lead to functional differences in speed and safety of spike conduction. Methodology/Principal Findings Confocal microscopy was used to systematically evaluate peripheral and central process diameters, commonness of myelination and morphology of spiral ganglion neurons (SGNs) along the cochlea of three human and three cats. Based on these morphometric data, model analysis reveales that spike conduction in SGNs is characterized by four phases: a postsynaptic delay, constant velocity in the peripheral process, a presomatic delay and constant velocity in the central process. The majority of SGNs are type I, connecting the inner hair cells with the brainstem. In contrast to those of humans, type I neurons of the cat are entirely myelinated. Biophysical model evaluation showed delayed and weak spikes in the human soma region as a consequence of a lack of myelin. The simulated spike conduction times are in accordance with normal interwave latencies from auditory brainstem response recordings from man and cat. Simulated 400 pA postsynaptic currents from inner hair cell ribbon synapses were 15 times above threshold. They enforced quick and synchronous spiking. Both of these properties were not present in type II cells as they receive fewer and much weaker (∼26 pA) synaptic stimuli. Conclusions/Significance Wasting synaptic energy boosts spike initiation, which guarantees the rapid transmission of temporal fine structure of auditory signals. However, a lack of myelin in the soma regions of human type I neurons causes a large delay in spike conduction in comparison with cat neurons. The absent myelin, in combination with a longer peripheral process, causes quantitative differences of temporal parameters in the electrically stimulated human cochlea compared to the cat cochlea. PMID:24260179

Electrically-evoked frequency-following response (EFFR) in the auditory brainstem of guinea pigs.

PubMed

He, Wenxin; Ding, Xiuyong; Zhang, Ruxiang; Chen, Jing; Zhang, Daoxing; Wu, Xihong

2014-01-01

It is still a difficult clinical issue to decide whether a patient is a suitable candidate for a cochlear implant and to plan postoperative rehabilitation, especially for some special cases, such as auditory neuropathy. A partial solution to these problems is to preoperatively evaluate the functional integrity of the auditory neural pathways. For evaluating the strength of phase-locking of auditory neurons, which was not reflected in previous methods using electrically evoked auditory brainstem response (EABR), a new method for recording phase-locking related auditory responses to electrical stimulation, called the electrically evoked frequency-following response (EFFR), was developed and evaluated using guinea pigs. The main objective was to assess feasibility of the method by testing whether the recorded signals reflected auditory neural responses or artifacts. The results showed the following: 1) the recorded signals were evoked by neuron responses rather than by artifact; 2) responses evoked by periodic signals were significantly higher than those evoked by the white noise; 3) the latency of the responses fell in the expected range; 4) the responses decreased significantly after death of the guinea pigs; and 5) the responses decreased significantly when the animal was replaced by an electrical resistance. All of these results suggest the method was valid. Recording obtained using complex tones with a missing fundamental component and using pure tones with various frequencies were consistent with those obtained using acoustic stimulation in previous studies.

Effect of c-myc on the ultrastructural structure of cochleae in guinea pigs with noise induced hearing loss

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

Han, Yu; Zhong, Cuiping; Hong, Liu

2009-12-18

Noise over-stimulation may induce hair cells loss and hearing deficit. The c-myc oncogene is a major regulator for cell proliferation, growth, and apoptosis. However, the role of this gene in the mammalian cochlea is still unclear. The study was designed to firstly investigate its function under noise condition, from the aspect of cochlear ultrastructural changes. We had established the adenoviral vector of c-myc gene and delivered the adenovirus suspension into the scala tympani of guinea pigs 4 days before noise exposure. The empty adenoviral vectors were injected as control. Then, all subjects were exposed to 4-kHz octave-band noise at 110more » dB SPL for 8 h/day, 3 days consecutively. Auditory thresholds were assessed by auditory brainstem response, prior to and 7 days following noise exposure. On the seventh days after noise exposure, the cochlear sensory epithelia surface was observed microscopically and the cochleae were taken to study the ultrastructural changes. The results indicated that auditory threshold shift after noise exposure was higher in the ears treated with Ad.EGFP than that treated with Ad.c-myc-EGFP. Stereocilia loss and the disarrangement of outer hair cells were observed, with greater changes found in the Ad.EGFP group. Also, the ultrastructure changes were severe in the Ad.EGFP group, but not obvious in the Ad.c-myc-EGFP group. Therefore, c-myc gene might play an unexpected role in hearing functional and morphological protection from acoustic trauma.« less

Differential pathologies resulting from sound exposure: Tinnitus vs hearing loss

NASA Astrophysics Data System (ADS)

Longenecker, Ryan James

The first step in identifying the mechanism(s) responsible for tinnitus development would be to discover a neural correlate that is differentially expressed in tinnitus-positive compared to tinnitus negative animals. Previous research has identified several neural correlates of tinnitus in animals that have tested positive for tinnitus. However it is unknown whether all or some of these correlates are linked to tinnitus or if they are a byproduct of hearing loss, a common outcome of tinnitus induction. Abnormally high spontaneous activity has frequently been linked to tinnitus. However, while some studies demonstrate that hyperactivity positively correlates with behavioral evidence of tinnitus, others show that when all animals develop hyperactivity to sound exposure, not all exposed animals show evidence of tinnitus. My working hypothesis is that certain aspects of hyperactivity are linked to tinnitus while other aspects are linked to hearing loss. The first specific aim utilized the gap induced prepulse inhibition of the acoustic startle reflex (GIPAS) to monitor the development of tinnitus in CBA/CaJ mice during one year following sound exposure. Immediately after sound exposure, GIPAS testing revealed widespread gap detection deficits across all frequencies, which was likely due to temporary threshold shifts. However, three months after sound exposure these deficits were limited to a narrow frequency band and were consistently detected up to one year after exposure. This suggests the development of chronic tinnitus is a long lasting and highly dynamic process. The second specific aim assessed hearing loss in sound exposed mice using several techniques. Acoustic brainstem responses recorded initially after sound exposure reveal large magnitude deficits in all exposed mice. However, at the three month period, thresholds return to control levels in all mice suggesting that ABRs are not a reliable tool for assessing permanent hearing loss. Input/output functions of the acoustic startle reflex show that after sound exposure the magnitude of startle responses decrease in most mice, to varying degrees. Lastly, PPI audiometry was able to detect specific behavioral threshold deficits for each mouse after sound exposure. These deficits persist past initial threshold shifts and are able to detect frequency specific permanent threshold shifts. The third specific aim examined hyperactivity and increased bursting activity in the inferior colliculus after sound exposure in relation to tinnitus and hearing loss. Spontaneous firing rates were increased in all mice after sound exposure regardless of behavioral evidence of tinnitus. However, abnormal increased bursting activity was not found in the animals identified with tinnitus but was exhibited in a mouse with broad-band severe threshold deficits. CBA/CaJ mice are a good model for both tinnitus development and noise-induced hearing loss studies. Hyperactivity which was evident in all exposed animals does not seem to be well correlated with behavioral evidence of tinnitus but more likely to be a general result of acoustic over exposure. Data from one animal strongly suggest that wide-spread severe threshold deficits are linked to an elevation of bursting activity predominantly ipsilateral to the side of sound exposure. This result is intriguing and should be followed up in further studies. Data obtained in this study provide new insights into underlying neural pathologies following sound exposure and have possible clinical applications for development of effective treatments and diagnostic tools for tinnitus and hearing loss.

Focal brainstem gliomas

PubMed Central

Sabbagh, Abdulrahman J.; Alaqeel, Ahmed M.

2015-01-01

Improved neuronavigation guidance as well as intraoperative imaging and neurophysiologic monitoring technologies have enhanced the ability of neurosurgeons to resect focal brainstem gliomas. In contrast, diffuse brainstem gliomas are considered to be inoperable lesions. This article is a continuation of an article that discussed brainstem glioma diagnostics, imaging, and classification. Here, we address open surgical treatment of and approaches to focal, dorsally exophytic, and cervicomedullary brainstem gliomas. Intraoperative neuronavigation, intraoperative neurophysiologic monitoring, as well as intraoperative imaging are discussed as adjunctive measures to help render these procedures safer, more acute, and closer to achieving surgical goals. PMID:25864061

Attenuation of progressive hearing loss in DBA/2J mice by reagents that affect epigenetic modifications is associated with up-regulation of the zinc importer Zip4.

PubMed

Mutai, Hideki; Miya, Fuyuki; Fujii, Masato; Tsunoda, Tatsuhiko; Matsunaga, Tatsuo

2015-01-01

Various factors that are important for proper hearing have been identified, including serum levels of zinc. Here we investigated whether epigenetic regulatory pathways, which can be modified by environmental factors, could modulate hearing. RT-PCR detected expression of genes encoding DNA methyltransferase and histone deacetylase (Hdac) in the postnatal as well as adult mouse auditory epithelium. DBA/2J mice, which are a model for progressive hearing loss, were injected subcutaneously with one or a combination of the following reagents: L-methionine as a methyl donor, valproic acid as a pan-Hdac inhibitor, and folic acid and vitamin B12 as putative factors involved in age-related hearing loss. The mice were treated from ages 4 to 12 weeks (N ≥ 5), and auditory brainstem response (ABR) thresholds were measured at 8, 16, and 32 kHz. Treatment of the mice with a combination of L-methionine and valproic acid (M+V) significantly reduced the increase in the ABR threshold at 32 kHz. Treatment with any of these reagents individually produced no such effect. Microarray analyses detected 299 gene probes that were significantly up- or down-regulated in the cochleae of mice treated with M+V compared with the control vehicle-treated mice. Quantitative RT-PCR confirmed significant up-regulation of a zinc importer gene, Zip4, in the cochleae of mice treated with M+V. Immunohistochemistry demonstrated an intense Zip4 signal in cochlear tissues such as the lateral wall, organ of Corti, and spiral ganglion. Finally, mice treated with the Zip4 inducer (-)-epigallocatechin-3-O-gallate showed a significant reduction in the increase of the ABR threshold at 32 kHz and up-regulation of Zip4 expression in the cochlea. This study suggests that epigenetic regulatory pathways can modify auditory function and that zinc intake in the cochlea via Zip4 mediates maintenance of mammalian hearing.

Molecular mechanisms involved in cochlear implantation trauma and the protection of hearing and auditory sensory cells by inhibition of c-Jun-N-terminal kinase signaling.

PubMed

Eshraghi, Adrien A; Gupta, Chhavi; Van De Water, Thomas R; Bohorquez, Jorge E; Garnham, Carolyn; Bas, Esperanza; Talamo, Victoria Maria

2013-03-01

To investigate the molecular mechanisms involved in electrode insertion trauma (EIT) and to test the otoprotective effect of locally delivered AM-111. An animal model of cochlear implantation. Guinea pigs' hearing thresholds were measured by auditory brainstem response (ABR) before and after cochlear implantation in four groups: EIT; pretreated with hyaluronate gel 30 minutes before EIT (EIT+Gel); pretreated with hyaluronate gel/AM-111 30 minutes before EIT (EIT+AM-111); and unoperated contralateral ears as controls. Neurofilament, synapsin, and fluorescein isothiocyanate (FITC)-phalloidin staining for hair cell counts were performed at 90 days post-EIT. Immunostaining for 4-hydroxy-2-nonenal (HNE), activated caspase-3, CellROX, and phospho-c-Jun were performed at 24 hours post-EIT. ABR thresholds increased post-EIT in the cochleae of EIT only and EIT+Gel treated animals. There was no significant increase in hearing thresholds in cochleae from either EIT+AM-111 treated or unoperated control ears. AM-111 protection of organ of Corti sensory elements (i.e., hair cells [HCs], supporting cells [SCs], nerve fibers, and synapses) was documented at 3 months post-EIT. Immunostaining of 24-hour post-EIT specimens demonstrated increased levels of HNE in HCs and SCs; increased levels of CellROX and activation of caspase-3 was observed only in SCs, and phosphorylation of c-Jun occurred only in HCs of the EIT-only and EIT+Gel specimens. There was no immunostaining for either HNE, CellROX, caspase-3, or phospho-c-Jun in the organ of Corti specimens from AM-111 treated cochleae. Molecular mechanisms involved in programmed cell death of HCs are different than the ones involved in programmed cell death of SCs. Local delivery of AM-111 provided a significant level of protection against EIT-induced hearing losses, HC losses, and damage to neural elements. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

Pinpointing brainstem mechanisms responsible for autonomic dysfunction in Rett syndrome: therapeutic perspectives for 5-HT1A agonists

PubMed Central

Abdala, Ana P.; Bissonnette, John M.; Newman-Tancredi, Adrian

2014-01-01

Rett syndrome is a neurological disorder caused by loss of function of methyl-CpG-binding protein 2 (MeCP2). Reduced function of this ubiquitous transcriptional regulator has a devastating effect on the central nervous system. One of the most severe and life-threatening presentations of this syndrome is brainstem dysfunction, which results in autonomic disturbances such as breathing deficits, typified by episodes of breathing cessation intercalated with episodes of hyperventilation or irregular breathing. Defects in numerous neurotransmitter systems have been observed in Rett syndrome both in animal models and patients. Here we dedicate special attention to serotonin due to its role in promoting regular breathing, increasing vagal tone, regulating mood, alleviating Parkinsonian-like symptoms and potential for therapeutic translation. A promising new symptomatic strategy currently focuses on regulation of serotonergic function using highly selective serotonin type 1A (5-HT1A) “biased agonists.” We address this newly emerging therapy for respiratory brainstem dysfunction and challenges for translation with a holistic perspective of Rett syndrome, considering potential mood and motor effects. PMID:24910619

Extensive basal ganglia edema caused by a traumatic carotid-cavernous fistula: a rare presentation related to a basal vein of Rosenthal anatomical variation.

PubMed

Ract, Isabelle; Drier, Aurélie; Leclercq, Delphine; Sourour, Nader; Gabrieli, Joseph; Yger, Marion; Nouet, Aurélien; Dormont, Didier; Chiras, Jacques; Clarençon, Frédéric

2014-07-01

The authors report a very rare presentation of traumatic carotid-cavernous fistula (CCF) with extensive edema of the basal ganglia and brainstem because of an anatomical variation of the basal vein of Rosenthal (BVR). A 45-year-old woman was admitted to the authors' institution for left hemiparesis, dysarthria, and a comatose state caused by right orbital trauma from a thin metal rod. Brain MRI showed a right CCF and vasogenic edema of the right side of the brainstem, right temporal lobe, and basal ganglia. Digital subtraction angiography confirmed a high-flow direct CCF and revealed a hypoplastic second segment of the BVR responsible for the hypertension in inferior striate veins and venous congestion. Endovascular treatment was performed on an emergency basis. One month after treatment, the patient's symptoms and MRI signal abnormalities almost totally disappeared. Basal ganglia and brainstem venous congestion may occur in traumatic CCF in cases of a hypoplastic or agenetic second segment of the BVR and may provoke emergency treatment.

Different contributions of primary motor cortex, reticular formation, and spinal cord to fractionated muscle activation.

PubMed

Zaaimi, Boubker; Dean, Lauren R; Baker, Stuart N

2018-01-01

Coordinated movement requires patterned activation of muscles. In this study, we examined differences in selective activation of primate upper limb muscles by cortical and subcortical regions. Five macaque monkeys were trained to perform a reach and grasp task, and electromyogram (EMG) was recorded from 10 to 24 muscles while weak single-pulse stimuli were delivered through microelectrodes inserted in the motor cortex (M1), reticular formation (RF), or cervical spinal cord (SC). Stimulus intensity was adjusted to a level just above threshold. Stimulus-evoked effects were assessed from averages of rectified EMG. M1, RF, and SC activated 1.5 ± 0.9, 1.9 ± 0.8, and 2.5 ± 1.6 muscles per site (means ± SD); only M1 and SC differed significantly. In between recording sessions, natural muscle activity in the home cage was recorded using a miniature data logger. A novel analysis assessed how well natural activity could be reconstructed by stimulus-evoked responses. This provided two measures: normalized vector length L, reflecting how closely aligned natural and stimulus-evoked activity were, and normalized residual R, measuring the fraction of natural activity not reachable using stimulus-evoked patterns. Average values for M1, RF, and SC were L = 119.1 ± 9.6, 105.9 ± 6.2, and 109.3 ± 8.4% and R = 50.3 ± 4.9, 56.4 ± 3.5, and 51.5 ± 4.8%, respectively. RF was significantly different from M1 and SC on both measurements. RF is thus able to generate an approximation to the motor output with less activation than required by M1 and SC, but M1 and SC are more precise in reaching the exact activation pattern required. Cortical, brainstem, and spinal centers likely play distinct roles, as they cooperate to generate voluntary movements. NEW & NOTEWORTHY Brainstem reticular formation, primary motor cortex, and cervical spinal cord intermediate zone can all activate primate upper limb muscles. However, brainstem output is more efficient but less precise in producing natural patterns of motor output than motor cortex or spinal cord. We suggest that gross muscle synergies from the reticular formation are sculpted and refined by motor cortex and spinal circuits to reach the finely fractionated output characteristic of dexterous primate upper limb movements.

Different contributions of primary motor cortex, reticular formation, and spinal cord to fractionated muscle activation

PubMed Central

Dean, Lauren R.

2018-01-01

Coordinated movement requires patterned activation of muscles. In this study, we examined differences in selective activation of primate upper limb muscles by cortical and subcortical regions. Five macaque monkeys were trained to perform a reach and grasp task, and electromyogram (EMG) was recorded from 10 to 24 muscles while weak single-pulse stimuli were delivered through microelectrodes inserted in the motor cortex (M1), reticular formation (RF), or cervical spinal cord (SC). Stimulus intensity was adjusted to a level just above threshold. Stimulus-evoked effects were assessed from averages of rectified EMG. M1, RF, and SC activated 1.5 ± 0.9, 1.9 ± 0.8, and 2.5 ± 1.6 muscles per site (means ± SD); only M1 and SC differed significantly. In between recording sessions, natural muscle activity in the home cage was recorded using a miniature data logger. A novel analysis assessed how well natural activity could be reconstructed by stimulus-evoked responses. This provided two measures: normalized vector length L, reflecting how closely aligned natural and stimulus-evoked activity were, and normalized residual R, measuring the fraction of natural activity not reachable using stimulus-evoked patterns. Average values for M1, RF, and SC were L = 119.1 ± 9.6, 105.9 ± 6.2, and 109.3 ± 8.4% and R = 50.3 ± 4.9, 56.4 ± 3.5, and 51.5 ± 4.8%, respectively. RF was significantly different from M1 and SC on both measurements. RF is thus able to generate an approximation to the motor output with less activation than required by M1 and SC, but M1 and SC are more precise in reaching the exact activation pattern required. Cortical, brainstem, and spinal centers likely play distinct roles, as they cooperate to generate voluntary movements. NEW & NOTEWORTHY Brainstem reticular formation, primary motor cortex, and cervical spinal cord intermediate zone can all activate primate upper limb muscles. However, brainstem output is more efficient but less precise in producing natural patterns of motor output than motor cortex or spinal cord. We suggest that gross muscle synergies from the reticular formation are sculpted and refined by motor cortex and spinal circuits to reach the finely fractionated output characteristic of dexterous primate upper limb movements. PMID:29046427

Processing Complex Sounds Passing through the Rostral Brainstem: The New Early Filter Model

PubMed Central

Marsh, John E.; Campbell, Tom A.

2016-01-01

The rostral brainstem receives both “bottom-up” input from the ascending auditory system and “top-down” descending corticofugal connections. Speech information passing through the inferior colliculus of elderly listeners reflects the periodicity envelope of a speech syllable. This information arguably also reflects a composite of temporal-fine-structure (TFS) information from the higher frequency vowel harmonics of that repeated syllable. The amplitude of those higher frequency harmonics, bearing even higher frequency TFS information, correlates positively with the word recognition ability of elderly listeners under reverberatory conditions. Also relevant is that working memory capacity (WMC), which is subject to age-related decline, constrains the processing of sounds at the level of the brainstem. Turning to the effects of a visually presented sensory or memory load on auditory processes, there is a load-dependent reduction of that processing, as manifest in the auditory brainstem responses (ABR) evoked by to-be-ignored clicks. Wave V decreases in amplitude with increases in the visually presented memory load. A visually presented sensory load also produces a load-dependent reduction of a slightly different sort: The sensory load of visually presented information limits the disruptive effects of background sound upon working memory performance. A new early filter model is thus advanced whereby systems within the frontal lobe (affected by sensory or memory load) cholinergically influence top-down corticofugal connections. Those corticofugal connections constrain the processing of complex sounds such as speech at the level of the brainstem. Selective attention thereby limits the distracting effects of background sound entering the higher auditory system via the inferior colliculus. Processing TFS in the brainstem relates to perception of speech under adverse conditions. Attentional selectivity is crucial when the signal heard is degraded or masked: e.g., speech in noise, speech in reverberatory environments. The assumptions of a new early filter model are consistent with these findings: A subcortical early filter, with a predictive selectivity based on acoustical (linguistic) context and foreknowledge, is under cholinergic top-down control. A prefrontal capacity limitation constrains this top-down control as is guided by the cholinergic processing of contextual information in working memory. PMID:27242396

Processing Complex Sounds Passing through the Rostral Brainstem: The New Early Filter Model.

PubMed

Marsh, John E; Campbell, Tom A

2016-01-01

The rostral brainstem receives both "bottom-up" input from the ascending auditory system and "top-down" descending corticofugal connections. Speech information passing through the inferior colliculus of elderly listeners reflects the periodicity envelope of a speech syllable. This information arguably also reflects a composite of temporal-fine-structure (TFS) information from the higher frequency vowel harmonics of that repeated syllable. The amplitude of those higher frequency harmonics, bearing even higher frequency TFS information, correlates positively with the word recognition ability of elderly listeners under reverberatory conditions. Also relevant is that working memory capacity (WMC), which is subject to age-related decline, constrains the processing of sounds at the level of the brainstem. Turning to the effects of a visually presented sensory or memory load on auditory processes, there is a load-dependent reduction of that processing, as manifest in the auditory brainstem responses (ABR) evoked by to-be-ignored clicks. Wave V decreases in amplitude with increases in the visually presented memory load. A visually presented sensory load also produces a load-dependent reduction of a slightly different sort: The sensory load of visually presented information limits the disruptive effects of background sound upon working memory performance. A new early filter model is thus advanced whereby systems within the frontal lobe (affected by sensory or memory load) cholinergically influence top-down corticofugal connections. Those corticofugal connections constrain the processing of complex sounds such as speech at the level of the brainstem. Selective attention thereby limits the distracting effects of background sound entering the higher auditory system via the inferior colliculus. Processing TFS in the brainstem relates to perception of speech under adverse conditions. Attentional selectivity is crucial when the signal heard is degraded or masked: e.g., speech in noise, speech in reverberatory environments. The assumptions of a new early filter model are consistent with these findings: A subcortical early filter, with a predictive selectivity based on acoustical (linguistic) context and foreknowledge, is under cholinergic top-down control. A prefrontal capacity limitation constrains this top-down control as is guided by the cholinergic processing of contextual information in working memory.

Stimulation of the basal and central amygdala in the mustached bat triggers echolocation and agonistic vocalizations within multimodal output

PubMed Central

Ma, Jie; Kanwal, Jagmeet S.

2014-01-01

The neural substrate for the perception of vocalizations is relatively well described, but how their timing and specificity are tightly coupled with accompanying physiological changes and context-appropriate behaviors remains unresolved. We hypothesized that temporally integrated vocal and emotive responses, especially the expression of fear, vigilance and aggression, originate within the amygdala. To test this hypothesis, we performed electrical microstimulation at 461 highly restricted loci within the basal and central amygdala in awake mustached bats. At a subset of these sites, high frequency stimulation with weak constant current pulses presented at near-threshold levels triggered vocalization of either echolocation pulses or social calls. At the vast majority of locations, microstimulation produced a constellation of changes in autonomic and somatomotor outputs. These changes included widespread co-activation of significant tachycardia and hyperventilation and/or rhythmic ear pinna movements (PMs). In a few locations, responses were constrained to vocalization and/or PMs despite increases in the intensity of stimulation. The probability of eliciting echolocation pulses vs. social calls decreased in a medial-posterior to anterolateral direction within the centrobasal amygdala. Microinjections of kainic acid (KA) at stimulation sites confirmed the contribution of cellular activity rather than fibers-of-passage in the control of multimodal outputs. The results suggest that localized clusters of neurons may simultaneously modulate the activity of multiple central pattern generators (CPGs) present within the brainstem. PMID:24624089

Stimulation of the basal and central amygdala in the mustached bat triggers echolocation and agonistic vocalizations within multimodal output.

PubMed

Ma, Jie; Kanwal, Jagmeet S

2014-01-01

The neural substrate for the perception of vocalizations is relatively well described, but how their timing and specificity are tightly coupled with accompanying physiological changes and context-appropriate behaviors remains unresolved. We hypothesized that temporally integrated vocal and emotive responses, especially the expression of fear, vigilance and aggression, originate within the amygdala. To test this hypothesis, we performed electrical microstimulation at 461 highly restricted loci within the basal and central amygdala in awake mustached bats. At a subset of these sites, high frequency stimulation with weak constant current pulses presented at near-threshold levels triggered vocalization of either echolocation pulses or social calls. At the vast majority of locations, microstimulation produced a constellation of changes in autonomic and somatomotor outputs. These changes included widespread co-activation of significant tachycardia and hyperventilation and/or rhythmic ear pinna movements (PMs). In a few locations, responses were constrained to vocalization and/or PMs despite increases in the intensity of stimulation. The probability of eliciting echolocation pulses vs. social calls decreased in a medial-posterior to anterolateral direction within the centrobasal amygdala. Microinjections of kainic acid (KA) at stimulation sites confirmed the contribution of cellular activity rather than fibers-of-passage in the control of multimodal outputs. The results suggest that localized clusters of neurons may simultaneously modulate the activity of multiple central pattern generators (CPGs) present within the brainstem.

Live CT imaging of sound reception anatomy and hearing measurements in the pygmy killer whale, Feresa attenuata.

PubMed

Montie, Eric W; Manire, Charlie A; Mann, David A

2011-03-15

In June 2008, two pygmy killer whales (Feresa attenuata) were stranded alive near Boca Grande, FL, USA, and were taken into rehabilitation. We used this opportunity to learn about the peripheral anatomy of the auditory system and hearing sensitivity of these rare toothed whales. Three-dimensional (3-D) reconstructions of head structures from X-ray computed tomography (CT) images revealed mandibles that were hollow, lacked a bony lamina medial to the pan bone and contained mandibular fat bodies that extended caudally and abutted the tympanoperiotic complex. Using auditory evoked potential (AEP) procedures, the modulation rate transfer function was determined. Maximum evoked potential responses occurred at modulation frequencies of 500 and 1000 Hz. The AEP-derived audiograms were U-shaped. The lowest hearing thresholds occurred between 20 and 60 kHz, with the best hearing sensitivity at 40 kHz. The auditory brainstem response (ABR) was composed of seven waves and resembled the ABR of the bottlenose and common dolphins. By changing electrode locations, creating 3-D reconstructions of the brain from CT images and measuring the amplitude of the ABR waves, we provided evidence that the neuroanatomical sources of ABR waves I, IV and VI were the auditory nerve, inferior colliculus and the medial geniculate body, respectively. The combination of AEP testing and CT imaging provided a new synthesis of methods for studying the auditory system of cetaceans.

Chronic pain and pain processing in Parkinson's disease.

PubMed

Blanchet, Pierre J; Brefel-Courbon, Christine

2017-10-12

Pain is experienced by the vast majority of patients living with Parkinson's disease. It is most often of nociceptive origin, but may also be ascribed to neuropathic (radicular or central) or miscellaneous sources. The recently validated King's Parkinson's Disease Pain Scale is based on 7 domains including musculoskeletal pain, chronic body pain (central or visceral), fluctuation-related pain, nocturnal pain, oro-facial pain, pain with discolouration/oedema/swelling, and radicular pain. The basal ganglia integrate incoming nociceptive information and contribute to coordinated motor responses in pain avoidance and nocifensive behaviors. In Parkinson's disease, nigral and extra-nigral pathology, involving cortical areas, brainstem nuclei, and spinal cord, may contribute to abnormal central nociceptive processing in patients experiencing pain or not. The dopamine deficit lowers multimodal pain thresholds that are amenable to correction following levodopa dosing. Functional brain imaging with positron emission tomography following administration of H 2 15 O revealed abnormalities in the sensory discriminative processing of pain (insula/SII), as well as in the affective motivational processing of pain (anterior cingulate cortex, prefrontal cortex). Pain management is dependent on efforts invested in diagnostic accuracy to distinguish nociceptive from neuropathic pain. Treatment requires an integrated approach including strategies to lessen levodopa-related response fluctuations, in addition to other pharmacological and non-pharmacological options such as deep brain stimulation and rehabilitation. Copyright © 2017. Published by Elsevier Inc.

Reduced noise susceptibility in littermate offspring from heterozygous animals of the German waltzing guinea pig.

PubMed

Skjönsberg, Åsa; Mannström, Paula

2015-07-08

The German waltzing guinea pig is a spontaneously mutated strain with severe auditory and vestibular impairment caused by a so far unknown genetic mutation. The animals are born deaf and show a circling behavior. The heterozygote animals of this guinea pig strain have functionally normal hearing and balance. However, these animals have, in earlier studies, shown an increased resistance to noise compared with normal wild-type guinea pigs. In the present study, we explored the functional hearing with auditory brainstem response thresholds before and at different time points after noise exposure. Symptom-free littermates from heterozygote couples of the German waltzing guinea pigs were exclusively used for the study, which, after the hearing test, were sent back for breeding to confirm their genotype (i.e. heterozygote or normal). The aim of this paper was to ascertain that the previously shown reduced susceptibility to noise trauma in the heterozygote animals of the German waltzing guinea pig was also evident when littermates were used as control animals. The findings are important for further analysis of the heterozygote animals of this strain and for future investigations of the underlying mechanisms behind the diverse susceptibility to exposures of loud sound.

Time course of apoptotic cell death in guinea pig cochlea following intratympanic gentamicin application.

PubMed

Suzuki, Mitsuya; Ushio, Munetaka; Yamasoba, Tatsuya

2008-07-01

The present study showed that the molecular signal that promotes the death of cochlear hair cells (HCs) induced by intratympanic gentamicin application is significant before the manifestation of morphological and functional changes. The effect of agents that protect the HCs from aminoglycoside ototoxicity is influenced by the timing of their administration. However, morphological, functional and molecular changes in the cochlea in the early stage following aminoglycoside application have rarely been studied. Therefore, we examined the chronological changes in the cochlea following intratympanic gentamicin application. Small pieces of gelatin sponge soaked with gentamicin (40 mg/ml) were placed on the round window membrane of mature guinea pigs, and the tympanic bulla was filled with gentamicin solution. They were euthanized at 6, 12, 18, 24, and 48 h following gentamicin application. Auditory brainstem responses (ABRs) were measured before gentamicin application and immediately before euthanasia, and the extent of missing and TUNEL-positive HCs was evaluated. ABR thresholds significantly increased 18 h or later following gentamicin application, and the loss of HCs was seen at 24 and 48 h. While functional and morphological changes were not evident until 18 h after gentamicin application, substantial amounts of TUNEL-positive HCs appeared at 12 h.

[Magnetic resonance imaging study and cochlear implantation in post-meningitic deaf patients].

PubMed

Liu, Xiuli; Yao, Yiwen; He, Guili; Zhai, Lijie

2004-07-01

To investigate the clinical application of magnetic resonance imaging (MRI) in post-meningitic patients and its impact on surgical decision. The pre-operative MRI data and auditory brainstem response (ABR) examination of five post-meningitic patients were studied. They were implanted with cochleas. The interval between the onset of bacterial meningitis and the hearing loss was (15.8 +/- 15.0)d and it was longer in children than adults. Five ears showed membranous cochlear labyrinth abnormality; 3 ears had vestibule vestibule abnormality; 8 ears demonstrated semicircular canal abnormality on MRI examinations in totally 10 ears. The mean hearing threshold of 10 ears was (102.0 +/- 7.1)dB HL,that of the operated ears was (98.0 +/- 5.7)dB HL and that of the un-operated ears was (106.0 +/- 6.5)dB HL. It was (15.8 +/- 15.0)d from the bacterial meningitis onset to hearing loss. The interval is longer in children than adults. There were 3 ears that electrodes could not be inserted completely. The bacterial meningitis may cause the abnormalities of inner ears and the MRI before surgery is essential for the pre-operative planning of cochlear implant.

Study of the protective effect of dexamethasone on cisplatin-induced ototoxicity in rats.

PubMed

Capelo, Isabelle Oliveira Jatai; Batista, Avner Marcos Alves; Brito, Yuri Neyson Ferreira; Diniz, Krissia Braga; Brito, Gerly Anne de Castro; Freitas, Marcos Rabelo de

2017-10-01

To evaluate the ability of dexamethasone to protect against cisplatin (CDDP)-induced ototoxicity. Male Wistar rats were divided into the following three groups: 1) Control (C): 6 animals received intraperitoneal (IP) saline solution, 8 ml/kg/day for four days; 2) C + CDDP: 11 animals received 8 ml/kg/day of IP saline and, 90 min after saline administration, 8 mg/kg/day of IP CDDP for four days; and 3) DEXA15 + CDDP: 11 animals received IP dexamethasone 15 mg/kg/day and, 90 min after dexamethasone administration, received 8 mg/kg/day of IP CDDP for four days. It was found that dexamethasone did not protect against weight loss in CDDP-exposed animals. The mortality rate was comparable with that previously reported in the literature. The auditory threshold of animals in the DEXA15 + CDDP group was not significantly altered after exposure to CDDP. The stria vascularis of animals in the DEXA15 + CDDP group was partially preserved after CDDP exposure. Dexamethasone at the dose of 15 mg/kg/day partially protected against CDDP-induced ototoxicity, based on functional evaluation by brainstem evoked response audiontry (BERA) and morphological evaluation by optical microscopy. However, dexamethasone did not protect against systemic toxicity.

Precocious hearing in harbour porpoise neonates.

PubMed

Wahlberg, Magnus; Delgado-García, Lara; Kristensen, Jakob H

2017-02-01

Hearing is the primary sensory modality for toothed whales, but it is not known at which age it is fully developed. For newborn calves, hearing could fill an important function in maintaining contact with the mother and to develop echolocation skills. We non-invasively measured the auditory brainstem response (ABR) in two neonate (age 1-4 days) and three adult harbour porpoises (Phocoena phocoena). The stimuli consisted of clicks centred at 130 kHz, which is within the frequency band used for echolocation and communication in this species. The temporal pattern of the neonate ABRs was indistinguishable to the adult ones. There were no significant differences between calves and adults regarding hearing thresholds and ABR latencies. The ABR amplitudes were up to more than an order of magnitude larger in newborns than in adults, most likely due to the neonates' smaller size. These results indicate that hearing is fully developed within a day after birth, which suggests that harbour porpoise neonates have the earliest hearing development of any mammal studied so far. This may be explained by the evolutionary pressures imposed by the aquatic environment for a rapid development of the key sensory system in harbour porpoises.

Ferulic acid promotes survival and differentiation of neural stem cells to prevent gentamicin-induced neuronal hearing loss.

PubMed

Gu, Lintao; Cui, Xinhua; Wei, Wei; Yang, Jia; Li, Xuezhong

2017-11-15

Neural stem cells (NSCs) have exhibited promising potential in therapies against neuronal hearing loss. Ferulic acid (FA) has been widely reported to enhance neurogenic differentiation of different stem cells. We investigated the role of FA in promoting NSC transplant therapy to prevent gentamicin-induced neuronal hearing loss. NSCs were isolated from mouse cochlear tissues to establish in vitro culture, which were then treated with FA. The survival and differentiation of NSCs were evaluated. Subsequently, neurite outgrowth and excitability of the in vitro neuronal network were assessed. Gentamicin was used to induce neuronal hearing loss in mice, in the presence and absence of FA, followed by assessments of auditory brainstem response (ABR) and distortion product optoacoustic emissions (DPOAE) amplitude. FA promoted survival, neurosphere formation and differentiation of NSCs, as well as neurite outgrowth and excitability of in vitro neuronal network. Furthermore, FA restored ABR threshold shifts and DPOAE in gentamicin-induced neuronal hearing loss mouse model in vivo. Our data, for the first time, support potential therapeutic efficacy of FA in promoting survival and differentiation of NSCs to prevent gentamicin-induced neuronal hearing loss. Copyright © 2017 Elsevier Inc. All rights reserved.

A two-year longitudinal pilot MRI study of the brainstem in autism.

PubMed

Jou, Roger J; Frazier, Thomas W; Keshavan, Matcheri S; Minshew, Nancy J; Hardan, Antonio Y

2013-08-15

Research has demonstrated the potential role of the brainstem in the pathobiology of autism. Previous studies have suggested reductions in brainstem volume and a relationship between this structure and sensory abnormalities. However, little is known regarding the developmental aspects of the brainstem across childhood and adolescence. The goal of this pilot study was to examine brainstem development via MRI volumetry using a longitudinal research design. Participants included 23 boys with autism and 23 matched controls (age range=8-17 years), all without intellectual disability. Participants underwent structural MRI scans once at baseline and again at two-year follow-up. Brainstem volumetric measurements were performed using the BRAINS2 software package. There were no significant group differences in age, gender, handedness, and total brain volume; however, full-scale IQ was higher in controls. Autism and control groups showed different patterns of growth in brainstem volume. While whole brainstem volume remained stable in controls over the two-year period, the autism group showed increases with age reaching volumes comparable to controls by age 15 years. This increase of whole brainstem volume was primarily driven by bilateral increases in gray matter volume. Findings from this preliminary study are suggestive of developmental brainstem abnormalities in autism primarily involving gray matter structures. These findings are consistent with autism being conceptualized as a neurodevelopmental disorder with alterations in brain-growth trajectories. More longitudinal MRI studies are needed integrating longitudinal cognitive/behavioral data to confirm and elucidate the clinical significance of these atypical growth patterns. Copyright © 2013 Elsevier B.V. All rights reserved.

Brainstem timing: implications for cortical processing and literacy.

PubMed

Banai, Karen; Nicol, Trent; Zecker, Steven G; Kraus, Nina

2005-10-26

The search for a unique biological marker of language-based learning disabilities has so far yielded inconclusive findings. Previous studies have shown a plethora of auditory processing deficits in learning disabilities at both the perceptual and physiological levels. In this study, we investigated the association among brainstem timing, cortical processing of stimulus differences, and literacy skills. To that end, brainstem timing and cortical sensitivity to acoustic change [mismatch negativity (MMN)] were measured in a group of children with learning disabilities and normal-learning children. The learning-disabled (LD) group was further divided into two subgroups with normal and abnormal brainstem timing. MMNs, literacy, and cognitive abilities were compared among the three groups. LD individuals with abnormal brainstem timing were more likely to show reduced processing of acoustic change at the cortical level compared with both normal-learning individuals and LD individuals with normal brainstem timing. This group was also characterized by a more severe form of learning disability manifested by poorer reading, listening comprehension, and general cognitive ability. We conclude that abnormal brainstem timing in learning disabilities is related to higher incidence of reduced cortical sensitivity to acoustic change and to deficient literacy skills. These findings suggest that abnormal brainstem timing may serve as a reliable marker of a subgroup of individuals with learning disabilities. They also suggest that faulty mechanisms of neural timing at the brainstem may be the biological basis of malfunction in this group.

Binaural interaction in the auditory brainstem response: a normative study.

PubMed

Van Yper, Lindsey N; Vermeire, Katrien; De Vel, Eddy F J; Battmer, Rolf-Dieter; Dhooge, Ingeborg J M

2015-04-01

Binaural interaction can be investigated using auditory evoked potentials. A binaural interaction component can be derived from the auditory brainstem response (ABR-BIC) and is considered evidence for binaural interaction at the level of the brainstem. Although click ABR-BIC has been investigated thoroughly, data on 500 Hz tone-burst (TB) ABR-BICs are scarce. In this study, characteristics of click and 500 Hz TB ABR-BICs are described. Furthermore, reliability of both click and 500 Hz TB ABR-BIC are investigated. Eighteen normal hearing young adults (eight women, ten men) were included. ABRs were recorded in response to clicks and 500 Hz TBs. ABR-BICs were derived by subtracting the binaural response from the sum of the monaural responses measured in opposite ears. Good inter-rater reliability is obtained for both click and 500 Hz TB ABR-BICs. The most reliable peak in click ABR-BIC occurs at a mean latency of 6.06 ms (SD 0.354 ms). Reliable 500 Hz TB ABR-BIC are obtained with a mean latency of 9.47 ms (SD 0.678 ms). Amplitudes are larger for 500 Hz TB ABR-BIC than for clicks. The most reliable peak in click ABR-BIC occurs at the downslope of wave V. Five hundred Hertz TB ABR-BIC is characterized by a broad positivity occurring at the level of wave V. The ABR-BIC is a useful technique to investigate binaural interaction in certain populations. Examples are bilateral hearing aid users, bilateral cochlear implant users and bimodal listeners. The latter refers to the combination of unilateral cochlear implantation and contralateral residual hearing. The majority of these patients have residual hearing in the low frequencies. The current study suggests that 500 Hz TB ABR-BIC may be a suitable technique to assess binaural interaction in this specific population of cochlear implant users. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Long-term survival of an infant with diffuse brainstem lesion diagnosed by prenatal MRI: a case report and review of the literature.

PubMed

Suo-Palosaari, M; Rantala, H; Lehtinen, S; Kumpulainen, T; Salokorpi, N

2016-06-01

We describe a unique case of expansive diffuse brainstem lesion diagnosed prenatally by magnetic resonance imaging (MRI) with long-term survival. Findings of fetal and postpartum MRI were highly consistent with the characteristics of diffuse brainstem glioma. Diagnosis was based on the features of MRI, and histopathology was not confirmed by biopsy. Although the prognosis of diffuse brainstem tumor is usually poor, this child was asymptomatic at birth and the neurological condition is still normal at 4 years of age without any treatment. During routine imaging follow-up, diameters of the expansion have remained stable, while the size of the lesion compared to the posterior fossa size has diminished. In addition to brainstem tumor, a skin lesion of the back was observed and MRI of the thoracic spine showed a large asymptomatic extradural cystic lesion suggesting an arachnoid cyst. The pontine tumor of this infant, in agreement with a few previously reported cases, suggests a subgroup of beneficial outcome of expansive diffuse brainstem lesions, particularly in the neonatal period. In this article, we discuss the prognosis and characteristics of pediatric brainstem tumors and differential diagnosis of neonatal brainstem lesions.

Neural Mechanisms of Emotion.

ERIC Educational Resources Information Center

Derryberry, Douglas; Tucker, Don M.

1992-01-01

Views neural mechanisms of emotion from an evolutionary perspective, seeing them distributed across the brainstem, limbic, paralimbic, and neocortical regions. Discusses descending and ascending connections among these levels in relation to three types of emotional processes: peripheral effects on patterned bodily responses, central effects on…

A clinical study of electrophysiological correlates of behavioural comfort levels in cochlear implantees.

PubMed

Raghunandhan, S; Ravikumar, A; Kameswaran, Mohan; Mandke, Kalyani; Ranjith, R

2014-05-01

Indications for cochlear implantation have expanded today to include very young children and those with syndromes/multiple handicaps. Programming the implant based on behavioural responses may be tedious for audiologists in such cases, wherein matching an effective Measurable Auditory Percept (MAP) and appropriate MAP becomes the key issue in the habilitation program. In 'Difficult to MAP' scenarios, objective measures become paramount to predict optimal current levels to be set in the MAP. We aimed to (a) study the trends in multi-modal electrophysiological tests and behavioural responses sequentially over the first year of implant use; (b) generate normative data from the above; (c) correlate the multi-modal electrophysiological thresholds levels with behavioural comfort levels; and (d) create predictive formulae for deriving optimal comfort levels (if unknown), using linear and multiple regression analysis. This prospective study included 10 profoundly hearing impaired children aged between 2 and 7 years with normal inner ear anatomy and no additional handicaps. They received the Advanced Bionics HiRes 90 K Implant with Harmony Speech processor and used HiRes-P with Fidelity 120 strategy. They underwent, impedance telemetry, neural response imaging, electrically evoked stapedial response telemetry (ESRT), and electrically evoked auditory brainstem response (EABR) tests at 1, 4, 8, and 12 months of implant use, in conjunction with behavioural mapping. Trends in electrophysiological and behavioural responses were analyzed using paired t-test. By Karl Pearson's correlation method, electrode-wise correlations were derived for neural response imaging (NRI) thresholds versus most comfortable level (M-levels) and offset based (apical, mid-array, and basal array) correlations for EABR and ESRT thresholds versus M-levels were calculated over time. These were used to derive predictive formulae by linear and multiple regression analysis. Such statistically predicted M-levels were compared with the behaviourally recorded M-levels among the cohort, using Cronbach's alpha reliability test method for confirming the efficacy of this method. NRI, ESRT, and EABR thresholds showed statistically significant positive correlations with behavioural M-levels, which improved with implant use over time. These correlations were used to derive predicted M-levels using regression analysis. On an average, predicted M-levels were found to be statistically reliable and they were a fair match to the actual behavioural M-levels. When applied in clinical practice, the predicted values were found to be useful for programming members of the study group. However, individuals showed considerable deviations in behavioural M-levels, above and below the electrophysiologically predicted values, due to various factors. While the current method appears helpful as a reference to predict initial maps in 'difficult to Map' subjects, it is recommended that behavioural measures are mandatory to further optimize the maps for these individuals. The study explores the trends, correlations and individual variabilities that occur between electrophysiological tests and behavioural responses, recorded over time among a cohort of cochlear implantees. The statistical method shown may be used as a guideline to predict optimal behavioural levels in difficult situations among future implantees, bearing in mind that optimal M-levels for individuals can vary from predicted values. In 'Difficult to MAP' scenarios, following a protocol of sequential behavioural programming, in conjunction with electrophysiological correlates will provide the best outcomes.

Audiological characteristics of infants with abnormal transient evoked otoacoustic emission and normal auditory brainstem response.

PubMed

Huang, Lihui; Han, Demin; Guo, Ying; Liu, Sha; Cui, Xiaoyan; Mo, Lingyan; Qi, Beier; Cai, Zhenghua; Liu, Hui; En, Hui; Guo, Liansheng

2008-10-01

Audiological characteristics were investigated in 81 ears of 53 infants with abnormal transient evoked otoacoustic emission (TEOAE) and normal auditory brainstem response (ABR). The relationship between ABR and other hearing testing methods, including 40Hz auditory event-related potential (40Hz-AERP), auditory steady state response (ASSR), distortion product otoacoustic emission (DPOAE), tympanometry, and acoustic reflex, was analyzed. Of the 81 ears, 18 ears (22.2%) were normal, while 63 ears (77.8%) were abnormal according to the tests. Testing of the 40 Hz AERP (36 ears) and ASSR (45 ears) revealed that 14 ears (38.9%) and 27 ears (60.0%) were abnormal, respectively. Testing of DPOAE in 68 ears revealed that 50 ears (73.5%) were abnormal. Testing of tympanometry in 50 ears and acoustic reflex in 47 ears revealed that 9 ears (18%) and 27 ears (57.4%) were abnormal, respectively. The present data suggests that the hearing of infants cannot be sufficiently evaluated with ABR only and that it must be evaluated with integrative audiological testing methods.

Lung respiratory rhythm and pattern generation in the bullfrog: role of neurokinin-1 and mu-opioid receptors.

PubMed

Davies, B L; Brundage, C M; Harris, M B; Taylor, B E

2009-07-01

Location of the lung respiratory rhythm generator (RRG) in the bullfrog brainstem was investigated by examining neurokinin-1 and mu-opioid receptor (NK1R, muOR) colocalization by immunohistochemistry and characterizing the role of these receptors in lung rhythm and episodic pattern generation. NK1R and muOR occurred in brainstems from all developmental stages. In juvenile bullfrogs a distinct area of colocalization was coincident with high-intensity fluorescent labeling of muOR; high-intensity labeling of muOR was not distinctly and consistently localized in tadpole brainstems. NK1R labeling intensity did not change with development. Similarity in colocalization is consistent with similarity in responses to substance P (SP, NK1R agonist) and DAMGO (muOR agonist) when bath applied to bullfrog brainstems of different developmental stages. In early stage tadpoles and juvenile bullfrogs, SP increased and DAMGO decreased lung burst frequency. In juvenile bullfrogs, SP increased lung burst frequency, episode frequency, but decreased number of lung bursts per episode and lung burst duration. In contrast, DAMGO decreased lung burst frequency and burst cycle frequency, episode frequency, and number of lung bursts per episode but increased all other lung burst parameters. Based on these results, we hypothesize that NK1R and muOR colocalization together with a metamorphosis-related increase in muOR intensity marks the location of the lung RRG but not necessarily the lung episodic pattern generator.

A long-term high-fat diet increases oxidative stress, mitochondrial damage and apoptosis in the inner ear of D-galactose-induced aging rats.

PubMed

Du, Zhengde; Yang, Yang; Hu, Yujuan; Sun, Yu; Zhang, Sulin; Peng, Wei; Zhong, Yi; Huang, Xiang; Kong, Weijia

2012-05-01

In humans, chronic dyslipidemia associated with elevated triglycerides may reduce auditory function. However, there is little evidence available in the literature concerning the effects of a long-term high-fat diet (HFD) on the inner ears of animals. The purpose of this study was to investigate the effect of 12 month-HFD on the inner ear of Sprague-Dawley rats and on the D-galactose (D-gal)-induced aging process in the inner ear. We found that 12 month-HFD markedly elevated the auditory brainstem response (ABR) threshold in the high-frequency region. The HFD significantly increased the generation of reactive oxygen species (ROS) and the expressions of NADPH oxidase (NOX) and the uncoupling proteins (UCP). Furthermore, an elevated accumulation of the mitochondrial DNA (mtDNA) common deletion (CD) and mitochondrial ultrastructural changes in the inner ear suggested that there was mitochondrial damage in response to the excessive fat intake. The expression level of cleaved caspase-3 and the number of terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end-labelling (TUNEL)-positive cells in the inner ear were increased by the HFD. The effects of D-gal on the inner ears were similar with 12 month-HFD. We found that rats receiving both the HFD and D-gal exhibited a greater shift in the ABR threshold, larger increases in the expression levels of NOX, UCP and cleaved caspase-3 and an increased number of TUNEL-positive cells in the inner ear. The present study demonstrated that HFD may induce oxidative stress, mitochondrial damage and apoptosis in the inner ear, and it provided evidence regarding the link between HFD and an increased risk of age-related hearing loss. Copyright © 2012 Elsevier B.V. All rights reserved.

Correlation of Acute and Late Brainstem Toxicities With Dose-Volume Data for Pediatric Patients With Posterior Fossa Malignancies

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

Nanda, Ronica H., E-mail: rhazari@emory.edu; Ganju, Rohit G.; Schreibmann, Edward

Purpose: Radiation-induced brainstem toxicity after treatment of pediatric posterior fossa malignancies is incompletely understood, especially in the era of intensity modulated radiation therapy (IMRT). The rates of, and predictive factors for, brainstem toxicity after photon RT for posterior fossa tumors were examined. Methods and Materials: After institutional review board approval, 60 pediatric patients treated at our institution for nonmetastatic infratentorial ependymoma and medulloblastoma with IMRT were included in the present analysis. Dosimetric variables, including the mean and maximum dose to the brainstem, the dose to 10% to 90% of the brainstem (in 10% increments), and the volume of the brainstemmore » receiving 40, 45, 50, and 55 Gy were recorded for each patient. Acute (onset within 3 months) and late (>3 months of RT completion) RT-induced brainstem toxicities with clinical and radiographic correlates were scored using Common Terminology Criteria for Adverse Events, version 4.0. Results: Patients aged 1.4 to 21.8 years underwent IMRT or volumetric arc therapy postoperatively to the posterior fossa or tumor bed. At a median clinical follow-up period of 2.8 years, 14 patients had developed symptomatic brainstem toxicity (crude incidence 23.3%). No correlation was found between the dosimetric variables examined and brainstem toxicity. Vascular injury or ischemia showed a strong trend toward predicting brainstem toxicity (P=.054). Patients with grade 3 to 5 brainstem toxicity had undergone treatment to significant volumes of the posterior fossa. Conclusion: The results of the present series demonstrate a low, but not negligible, risk of brainstem radiation necrosis for pediatric patients with posterior fossa malignancies treated with IMRT. No specific dose-volume correlations were identified; however, modern treatment volumes might help limit the incidence of severe toxicity. Additional work investigating inherent biologic sensitivity might also provide further insight into this clinical problem.« less

Anodal Cerebellar Direct Current Stimulation Reduces Facilitation of Propriospinal Neurons in Healthy Humans.

PubMed

Chothia, Muhammed; Doeltgen, Sebastian; Bradnam, Lynley V

2016-01-01

Coordinated muscle synergies in the human upper limb are controlled, in part, by a neural distribution network located in the cervical spinal cord, known as the cervical propriospinal system. Studies in the cat and non-human primate indicate the cerebellum is indirectly connected to this system via output pathways to the brainstem. Therefore, the cerebellum may indirectly modulate excitability of putative propriospinal neurons (PNs) in humans during upper limb coordination tasks. This study aimed to test whether anodal direct current stimulation (DCS) of the cerebellum modulates PNs and upper limb coordination in healthy adults. The hypothesis was that cerebellar anodal DCS would reduce descending facilitation of PNs and improve upper limb coordination. Transcranial magnetic stimulation (TMS), paired with peripheral nerve stimulation, probed activity in facilitatory and inhibitory descending projections to PNs following an established protocol. Coordination was tested using a pursuit rotor task performed by the non-dominant (ipsilateral) hand. Anodal and sham DCS were delivered over the cerebellum ipsilateral to the non-dominant hand in separate experimental sessions. Anodal DCS was applied to a control site lateral to the vertex in a third session. Twelve right-handed healthy adults participated. Pairing TMS with sub-threshold peripheral nerve stimulation facilitated motor evoked potentials at intensities just above threshold in accordance with the protocol. Anodal cerebellar DCS reduced facilitation without influencing inhibition, but the reduction in facilitation was not associated with performance of the pursuit rotor task. The results of this study indicate dissociated indirect control over cervical PNs by the cerebellum in humans. Anodal DCS of the cerebellum reduced excitability in the facilitatory descending pathway with no effect on the inhibitory pathway to cervical PNs. The reduction in PN excitability is likely secondary to modulation of primary motor cortex or brainstem nuclei, and identifies a neuroanatomical pathway for the cerebellum to assist in coordination of upper limb muscle synergies in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

[An evaluation of clinical characteristics and prognosis of brain-stem infarction in diabetics].

PubMed

Lu, Zheng-qi; Li, Hai-yan; Hu, Xue-qiang; Zhang, Bing-jun

2011-01-01

To analyze the relationship between diabetics and the onset, clinical outcomes and prognosis of brainstem infarction, and to evaluate the impact of diabetes on brainstem infarction. Compare 172 cases of acute brainstem infarction in patients with or without diabetes. Analyze the associated risk factors of patients with brain-stem infarction in diabetics by multi-variate logistic regression analysis. Compare the National Institutes of Health Stroke Scale (NIHSS) and Modified Rankin scale (mRS) Score, pathogenetic condition and the outcome of the two groups in different times. The systolic blood pressure (SBP), TG, LDL-C, apolipoprotein B (Apo B), glutamyl transpeptidase (γ-GT), fibrinogen (Fb), fasting blood glucose (FPG) and glycosylated hemoglobin(HbA1c)in diabetic group were higher than those in non-diabetic group, which was statistically significant (P < 0.05). From multi-variate logistic regression analysis, γ-GT, Apo B and FPG were the risk predictors of diabetes with brainstem infarction(OR = 1.017, 4.667 and 3.173, respectively), while HDL-C was protective (OR = 0.288). HbA1c was a risk predictor of severity for acute brainstem infarction (OR = 1.299), while Apo A was beneficial (OR = 0.212). Compared with brain-stem infarction in non-diabetic group, NIHSS score and intensive care therapy of diabetic groups on the admission had no statistically significance, while the NIHSS score on discharge and the outcome at 6 months' of follow-up were statistically significant. Diabetes is closely associated with brainstem infarction. Brainstem infarction with diabetes cause more rapid progression, poorer prognosis, higher rates of mortality as well as disability and higher recurrence rate of cerebral infarction.

Pinniped Hearing in Complex Acoustic Environments

DTIC Science & Technology

2013-09-30

published] Mulsow, J. & Reichmuth, C. (2013). The binaural click-evoked auditory brainstem response of the California sea lion (Zalophus...California sea lion can keep the beat : Motor entrainment to rhythmic auditory stimuli in a non vocal mimic. Journal of Comparative Psychology, online first. [published

Brainstem Auditory Evoked Potential in HIV-Positive Adults.

PubMed

Matas, Carla Gentile; Samelli, Alessandra Giannella; Angrisani, Rosanna Giaffredo; Magliaro, Fernanda Cristina Leite; Segurado, Aluísio C

2015-10-20

To characterize the findings of brainstem auditory evoked potential in HIV-positive individuals exposed and not exposed to antiretroviral treatment. This research was a cross-sectional, observational, and descriptive study. Forty-five HIV-positive individuals (18 not exposed and 27 exposed to the antiretroviral treatment - research groups I and II, respectively - and 30 control group individuals) were assessed through brainstem auditory evoked potential. There were no significant between-group differences regarding wave latencies. A higher percentage of altered brainstem auditory evoked potential was observed in the HIV-positive groups when compared to the control group. The most common alteration was in the low brainstem. HIV-positive individuals have a higher percentage of altered brainstem auditory evoked potential that suggests central auditory pathway impairment when compared to HIV-negative individuals. There was no significant difference between individuals exposed and not exposed to antiretroviral treatment.

Distribution of CGRP in the minipig brainstem.

PubMed

Lisardo Sánchez, Manuel; Vecino, Elena; Coveñas, Rafael

2014-05-01

For the first time, an in-depth study has been made of the distribution of fibers and cell bodies containing calcitonin gene-related peptide (CGRP) in the minipig brainstem using an indirect immunoperoxidase technique. The animals studied were not treated with colchicine. Cell bodies containing CGRP were found in 20 nuclei/regions of the brainstem. These perikarya were located in somatomotor, brachiomotor and raphae nuclei, nucleus ambiguus, substantia nigra, nucleus reticularis tegmenti pontis, nucleus prepositus hypoglossi, nuclei olivaris inferior and superior, nuclei pontis, formatio reticularis, nucleus dorsalis tegmenti of Gudden, and in the nucleus reticularis lateralis. Fourteen of the 20 brainstem nuclei showed a high density of immunoreactive cell bodies. In comparison with other species, the minipig, together with the rat, show the most widespread distribution of cell bodies containing CGRP in the mammalian brainstem. Immunoreactive fibers were also observed in the brainstem. However, in the minipig brainstem the density of these fibers is low, as in many brainstem nuclei only single immunoreactive fibers were observed. A high density of immunoreactive fibers was only observed in the pars caudalis of the nucleus tractus spinalis nervi trigemini and in the nucleus ventralis tegmenti of Gudden. According to the observed anatomical distribution of the immunoreactive structures containing CGRP, the peptide could be involved in motor, somatosensory, gustative, and autonomic mechanisms. Copyright © 2014 Wiley Periodicals, Inc.

Transcranial sonography of brainstem structures in panic disorder.

PubMed

Šilhán, Petr; Jelínková, Monika; Walter, Uwe; Pavlov Praško, Ján; Herzig, Roman; Langová, Kateřina; Školoudík, David

2015-10-30

Panic disorder has been associated with altered serotonin metabolism in the brainstem raphe. The aim of study was to evaluate the BR echogenicity on transcranial sonography (TCS) in panic disorder. A total of 96 healthy volunteers were enrolled in the "derivation" cohort, and 26 healthy volunteers and 26 panic disorder patients were enrolled in the "validation" cohort. TCS echogenicity of brainstem raphe and substantia nigra was assessed on anonymized images visually and by means of digitized image analysis. Significantly reduced brainstem raphe echogenicity was detected more frequently in panic disorder patients than in controls using both visual (68% vs. 31%) and digitized image analysis (52% vs. 12%). The optimal cut-off value of digitized brainstem raphe echogenicity indicated the diagnosis of panic disorder with a sensitivity of 64% and a specificity of 73%, and corresponded to the 30th percentile in the derivation cohort. Reduced brainstem raphe echogenicity was associated with shorter treatment duration, and, by trend, lower severity of anxiety. No relationship was found between echogenicity of brainstem raphe or substantia nigra and age, gender, severity of panic disorder, or severity of depression. Patients with panic disorder exhibit changes of brainstem raphe on TCS suggesting an alteration of the central serotonergic system. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Neonate Auditory Brainstem Responses to CE-Chirp and CE-Chirp Octave Band Stimuli II: Versus Adult Auditory Brainstem Responses.

PubMed

Cobb, Kensi M; Stuart, Andrew

The purpose of the study was to examine the differences in auditory brainstem response (ABR) latency and amplitude indices to the CE-Chirp stimuli in neonates versus young adults as a function of stimulus level, rate, polarity, frequency and gender. Participants were 168 healthy neonates and 20 normal-hearing young adults. ABRs were obtained to air- and bone-conducted CE-Chirps and air-conducted CE-Chirp octave band stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps. The effect of stimulus level was also examined with bone-conducted CE-Chirps and CE-Chirp octave band stimuli. The effect of gender was examined across all stimulus manipulations. In general, ABR wave V amplitudes were significantly larger (p < 0.0001) and latencies were significantly shorter (p < 0.0001) for adults versus neonates for all air-conducted CE-Chirp stimuli with all stimulus manipulations. For bone-conducted CE-Chirps, infants had significantly shorter wave V latencies than adults at 15 dB nHL and 45 dB nHL (p = 0.02). Adult wave V amplitude was significantly larger for bone-conducted CE-Chirps only at 30 dB nHL (p = 0.02). The effect of gender was not statistically significant across all measures (p > 0.05). Significant differences in ABR latencies and amplitudes exist between newborns and young adults using CE-Chirp stimuli. These differences are consistent with differences to traditional click and tone burst stimuli and reflect maturational differences as a function of age. These findings continue to emphasize the importance of interpreting ABR results using age-based normative data.

Non-homeostatic body weight regulation through a brainstem-restricted receptor for GDF15

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

Hsu, Jer-Yuan; Crawley, Suzanne; Chen, Michael

Under homeostatic conditions, animals use well-defined hypothalamic neural circuits to help maintain stable body weight, by integrating metabolic and hormonal signals from the periphery to balance food consumption and energy expenditure1,2. In stressed or disease conditions, however, animals use alternative neuronal pathways to adapt to the metabolic challenges of altered energy demand3. Recent studies have identified brain areas outside the hypothalamus that are activated under these ‘non-homeostatic’ conditions4,5,6, but the molecular nature of the peripheral signals and brain-localized receptors that activate these circuits remains elusive. Here we identify glial cell-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) as a brainstem-restricted receptormore » for growth and differentiation factor 15 (GDF15). GDF15 regulates food intake, energy expenditure and body weight in response to metabolic and toxin-induced stresses; we show that Gfral knockout mice are hyperphagic under stressed conditions and are resistant to chemotherapy-induced anorexia and body weight loss. GDF15 activates GFRAL-expressing neurons localized exclusively in the area postrema and nucleus tractus solitarius of the mouse brainstem. It then triggers the activation of neurons localized within the parabrachial nucleus and central amygdala, which constitute part of the ‘emergency circuit’ that shapes feeding responses to stressful conditions7. GDF15 levels increase in response to tissue stress and injury, and elevated levels are associated with body weight loss in numerous chronic human diseases8,9. By isolating GFRAL as the receptor for GDF15-induced anorexia and weight loss, we identify a mechanistic basis for the non-homeostatic regulation of neural circuitry by a peripheral signal associated with tissue damage and stress. These findings provide opportunities to develop therapeutic agents for the treatment of disorders with altered energy demand.« less

Perinatal Fluoxetine Exposure Impairs the CO2 Chemoreflex. Implications for Sudden Infant Death Syndrome.

PubMed

Bravo, Karina; Eugenín, Jaime L; Llona, Isabel

2016-09-01

High serotonin levels during pregnancy affect central nervous system development. Whether a commonly used antidepressant such as fluoxetine (a selective serotonin reuptake inhibitor) taken during pregnancy may adversely affect respiratory control in offspring has not been determined. The objective was to determine the effect of prenatal-perinatal fluoxetine exposure on the respiratory neural network in offspring, particularly on central chemoreception. Osmotic minipumps implanted into CF-1 mice on Days 5-7 of pregnancy delivered 7 milligrams per kilogram per day of fluoxetine, achieving plasma levels within the range found in patients. Ventilation was assessed in offspring at postnatal Days 0-40 using head-out body plethysmography. Neuronal activation was evaluated in the raphe nuclei and in the nucleus tractus solitarius by c-Fos immunohistochemistry during normoxic eucapnia and hypercapnia (10% CO2). Respiratory responses to acidosis were evaluated in brainstem slices. Prenatal-perinatal fluoxetine did not affect litter size, birth weight, or the postnatal growth curve. Ventilation under eucapnic normoxic conditions was similar to that of control offspring. Fluoxetine exposure reduced ventilatory responses to hypercapnia at P8-P40 (P < 0.001) but not at P0-P5. At P8, it reduced hypercapnia-induced neuronal activation in raphe nuclei (P < 0.05) and nucleus tractus solitarius (P < 0.01) and the acidosis-induced increase in the respiratory frequency in brainstem slices (P < 0.05). Fluoxetine applied acutely on control slices did not modify their respiratory response to acidosis. We concluded that prenatal-perinatal fluoxetine treatment impairs central respiratory chemoreception during postnatal life. These results are relevant in understanding the pathogenesis of respiratory failures, such as sudden infant death syndrome, associated with brainstem serotonin abnormalities and the failure of respiratory chemoreflexes.

Auditory evoked functions in ground crew working in high noise environment of Mumbai airport.

PubMed

Thakur, L; Anand, J P; Banerjee, P K

2004-10-01

The continuous exposure to the relatively high level of noise in the surroundings of an airport is likely to affect the central pathway of the auditory system as well as the cognitive functions of the people working in that environment. The Brainstem Auditory Evoked Responses (BAER), Mid Latency Response (MLR) and P300 response of the ground crew employees working in Mumbai airport were studied to evaluate the effects of continuous exposure to high level of noise of the surroundings of the airport on these responses. BAER, P300 and MLR were recorded by using a Nicolet Compact-4 (USA) instrument. Audiometry was also monitored with the help of GSI-16 Audiometer. There was a significant increase in the peak III latency of the BAER in the subjects exposed to noise compared to controls with no change in their P300 values. The exposed group showed hearing loss at different frequencies. The exposure to the high level of noise caused a considerable decline in the auditory conduction upto the level of the brainstem with no significant change in conduction in the midbrain, subcortical areas, auditory cortex and associated areas. There was also no significant change in cognitive function as measured by P300 response.

Rapid adenosine release in the nucleus tractus solitarii during defence response in rats: real-time measurement in vivo

PubMed Central

Dale, Nicholas; Gourine, Alexander V; Llaudet, Enrique; Bulmer, David; Thomas, Teresa; Spyer, K Michael

2002-01-01

We have measured the release of adenosine and inosine from the dorsal surface of the brainstem and from within the nucleus tractus solitarii (NTS) during the defence response evoked by hypothalamic stimulation in the anaesthetised rat. At the surface of the brainstem, only release of inosine was detected on hypothalamic defence area stimulation. This inosine signal was greatly reduced by addition of the ecto-5′-nucleotidase inhibitor α,β-methylene ADP (200 μM), suggesting that the inosine arose from adenosine that was produced in the extracellular space by the prior release of ATP. By placing a microelectrode biosensor into the NTS under stereotaxic control we have recorded release of adenosine within this nucleus. By contrast to the brainstem surface, a fast increase in adenosine, accompanied only by a much smaller change in inosine levels, was seen following stimulation of the hypothalamic defence area. The release of adenosine following hypothalamic stimulation was mainly confined to a narrow region of the NTS some 500 μm in length around the level of the obex. Interestingly the release of adenosine was depletable: when the defence reaction was evoked at short time intervals, much less adenosine was released on the second stimulus. Our novel techniques have given unprecedented real-time measurement and localisation of adenosine release in vivo and demonstrate that adenosine is released at the right time and in sufficient quantities to contribute to the cardiovascular components of the defence reaction. PMID:12356888

Plasticity of vagal brainstem circuits in the control of gastric function

PubMed Central

Browning, Kirsteen N.; Travagli, R. Alberto

2010-01-01

Background Sensory information from the viscera, including the gastrointestinal (GI) tract, is transmitted through the afferent vagus via a glutamatergic synapse to neurons of the nucleus tractus solitarius (NTS), which integrate this sensory information to regulate autonomic functions and homeostasis. The integrated response is conveyed to, amongst other nuclei, the preganglionic neurons of the dorsal motor nucleus of the vagus (DMV) using mainly GABA, glutamate and catecholamines as neurotransmitters. Despite being modulated by almost all the neurotransmitters tested so far, the glutamatergic synapse between NTS and DMV does not appear to be tonically active in the control of gastric motility and tone. Conversely, tonic inhibitory GABAergic neurotransmission from the NTS to the DMV appears critical in setting gastric tone and motility, yet, under basal conditions, this synapse appears resistant to modulation. Purpose Here, we review the available evidence suggesting that vagal efferent output to the GI tract is regulated, perhaps even controlled, in an “on-demand” and efficient manner in response to ever-changing homeostatic conditions. The focus of this review is on the plasticity induced by variations in the levels of second messengers in the brainstem neurons that form vago-vagal reflex circuits. Emphasis is placed upon the modulation of GABAergic transmission to DMV neurons and the modulation of afferent input from the GI tract by neurohormones/neurotransmitters and macronutrients. Derangement of this “on-demand” organization of brainstem vagal circuits may be one of the factors underlying the pathophysiological changes observed in functional dyspepsia or hyperglycemic gastroparesis. PMID:20804520

Value of intracochlear electrically evoked auditory brainstem response after cochlear implantation in patients with narrow internal auditory canal.

PubMed

Song, Mee Hyun; Bae, Mi Ran; Kim, Hee Nam; Lee, Won-Sang; Yang, Won Sun; Choi, Jae Young

2010-08-01

Cochlear implantation in patients with narrow internal auditory canal (IAC) can result in variable outcomes; however, preoperative evaluations have limitations in accurately predicting outcomes. In this study, we analyzed the outcomes of cochlear implantation in patients with narrow IAC and correlated the intracochlear electrically evoked auditory brainstem response (EABR) findings to postoperative performance to determine the prognostic significance of intracochlear EABR. Retrospective case series at a tertiary hospital. Thirteen profoundly deaf patients with narrow IAC who received cochlear implantation from 2002 to 2008 were included in this study. Postoperative performance was evaluated after at least 12 months of follow-up, and postoperative intracochlear EABR was measured to determine its correlation with outcome. The clinical significance of electrically evoked compound action potential (ECAP) was also analyzed. Patients with narrow IAC showed postoperative auditory performances ranging from CAP 0 to 4 after cochlear implantation. Intracochlear EABR measured postoperatively demonstrated prognostic value in the prediction of long-term outcomes, whereas ECAP measurements failed to show a significant correlation with outcome. Consistent with the advantages of intracochlear EABR over extracochlear EABR, this study demonstrates that intracochlear EABR has prognostic significance in predicting long-term outcomes in patients with narrow IAC. Intracochlear EABR measured either intraoperatively or in the early postoperative period may play an important role in deciding whether to continue with auditory rehabilitation using a cochlear implant or to switch to an auditory brainstem implant so as not to miss the optimal timing for language development.

Bone-Conduction ABR Tests.

ERIC Educational Resources Information Center

Cone-Wesson, Barbara

1995-01-01

This article discusses the accuracy of bone-conduction auditory brainstem response (BC-ABR) tests to determine the presence and severity of conductive hearing impairment. It provides warnings about technical pitfalls and recommends incorporating BC-ABR protocols for routine clinical use. It concludes that the method allows estimating cochlear…

Identification and Treatment of Very Young Children with Hearing Loss.

ERIC Educational Resources Information Center

Madell, Jane R.

1988-01-01

Hearing loss in infants and young children can be identified through behavioral observation audiometry, visual reinforcement audiometry, or auditory brainstem response testing. Habilitation may involve amplification with hearing aids, other assistive listening devices, or cochlear implants. Expectations for children with different degrees of…

Motor evoked potential monitoring of the vagus nerve with transcranial electrical stimulation during skull base surgeries.

PubMed

Ito, Eiji; Ichikawa, Masahiro; Itakura, Takeshi; Ando, Hitoshi; Matsumoto, Yuka; Oda, Keiko; Sato, Taku; Watanabe, Tadashi; Sakuma, Jun; Saito, Kiyoshi

2013-01-01

Dysphasia is one of the most serious complications of skull base surgeries and results from damage to the brainstem and/or cranial nerves involved in swallowing. Here, the authors propose a method to monitor the function of the vagus nerve using endotracheal tube surface electrodes and transcranial electrical stimulation during skull base surgeries. Fifteen patients with skull base or brainstem tumors were enrolled. The authors used surface electrodes of an endotracheal tube to record compound electromyographic responses from the vocalis muscle. Motor neurons were stimulated using corkscrew electrodes placed subdermally on the scalp at C3 and C4. During surgery, the operator received a warning when the amplitude of the vagal motor evoked potential (MEP) decreased to less than 50% of the control level. After surgery, swallowing function was assessed clinically using grading criteria. In 5 patients, vagal MEP amplitude permanently deteriorated to less than 50% of the control level on the right side when meningiomas were dissected from the pons or basilar artery, or when a schwannoma was dissected from the vagal rootlets. These 5 patients had postoperative dysphagia. At 4 weeks after surgery, 2 patients still had dysphagia. In 2 patients, vagal MEPs of one side transiently disappeared when the tumors were dissected from the brainstem or the vagal rootlets. After surgery, both patients had dysphagia, which recovered in 4 weeks. In 7 patients, MEP amplitude was consistent, maintaining more than 50% of the control level throughout the operative procedures. After surgery all 7 patients were neurologically intact with normal swallowing function. Vagal MEP monitoring with transcranial electrical stimulation and endotracheal tube electrode recording was a safe and effective method to provide continuous real-time information on the integrity of both the supranuclear and infranuclear vagal pathway. This method is useful to prevent intraoperative injury of the brainstem corticobulbar tract or the vagal rootlets and to avoid the postoperative dysphagia that is often associated with brainstem or skull base surgeries.

Gender Disparities in Speech-evoked Auditory Brainstem Response in Healthy Adults.

PubMed

Jalaei, Bahram; Zakaria, Mohd Normani; Mohd Azmi, Mohd Hafiz Afifi; Nik Othman, Nik Adilah; Sidek, Dinsuhaimi

2017-04-01

Gender disparities in speech-evoked auditory brainstem response (speech-ABR) outcomes have been reported, but the literature is limited. The present study was performed to further verify this issue and determine the influence of head size on speech-ABR results between genders. Twenty-nine healthy Malaysian subjects (14 males and 15 females) aged 19 to 30 years participated in this study. After measuring the head circumference, speech-ABR was recorded by using synthesized syllable /da/ from the right ear of each participant. Speech-ABR peaks amplitudes, peaks latencies, and composite onset measures were computed and analyzed. Significant gender disparities were noted in the transient component but not in the sustained component of speech-ABR. Statistically higher V/A amplitudes and less steeper V/A slopes were found in females. These gender differences were partially affected after controlling for the head size. Head size is not the main contributing factor for gender disparities in speech-ABR outcomes. Gender-specific normative data can be useful when recording speech-ABR for clinical purposes.

Principal cells of the brainstem's interaural sound level detector are temporal differentiators rather than integrators.

PubMed

Franken, Tom P; Joris, Philip X; Smith, Philip H

2018-06-14

The brainstem's lateral superior olive (LSO) is thought to be crucial for localizing high-frequency sounds by coding interaural sound level differences (ILD). Its neurons weigh contralateral inhibition against ipsilateral excitation, making their firing rate a function of the azimuthal position of a sound source. Since the very first in vivo recordings, LSO principal neurons have been reported to give sustained and temporally integrating 'chopper' responses to sustained sounds. Neurons with transient responses were observed but largely ignored and even considered a sign of pathology. Using the Mongolian gerbil as a model system, we have obtained the first in vivo patch clamp recordings from labeled LSO neurons and find that principal LSO neurons, the most numerous projection neurons of this nucleus, only respond at sound onset and show fast membrane features suggesting an importance for timing. These results provide a new framework to interpret previously puzzling features of this circuit. © 2018, Franken et al.

A probabilistic atlas of human brainstem pathways based on connectome imaging data.

PubMed

Tang, Yuchun; Sun, Wei; Toga, Arthur W; Ringman, John M; Shi, Yonggang

2018-04-01

The brainstem is a critical structure that regulates vital autonomic functions, houses the cranial nerves and their nuclei, relays motor and sensory information between the brain and spinal cord, and modulates cognition, mood, and emotions. As a primary relay center, the fiber pathways of the brainstem include efferent and afferent connections among the cerebral cortex, spinal cord, and cerebellum. While diffusion MRI has been successfully applied to map various brain pathways, its application for the in vivo imaging of the brainstem pathways has been limited due to inadequate resolution and large susceptibility-induced distortion artifacts. With the release of high-resolution data from the Human Connectome Project (HCP), there is increasing interest in mapping human brainstem pathways. Previous works relying on HCP data to study brainstem pathways, however, did not consider the prevalence (>80%) of large distortions in the brainstem even after the application of correction procedures from the HCP-Pipeline. They were also limited in the lack of adequate consideration of subject variability in either fiber pathways or region of interests (ROIs) used for bundle reconstruction. To overcome these limitations, we develop in this work a probabilistic atlas of 23 major brainstem bundles using high-quality HCP data passing rigorous quality control. For the large-scale data from the 500-Subject release of HCP, we conducted extensive quality controls to exclude subjects with severe distortions in the brainstem area. After that, we developed a systematic protocol to manually delineate 1300 ROIs on 20 HCP subjects (10 males; 10 females) for the reconstruction of fiber bundles using tractography techniques. Finally, we leveraged our novel connectome modeling techniques including high order fiber orientation distribution (FOD) reconstruction from multi-shell diffusion imaging and topography-preserving tract filtering algorithms to successfully reconstruct the 23 fiber bundles for each subject, which were then used to calculate the probabilistic atlases in the MNI152 space for public release. In our experimental results, we demonstrate that our method yielded anatomically faithful reconstruction of the brainstem pathways and achieved improved performance in comparison with an existing atlas of cerebellar peduncles based on HCP data. These atlases have been publicly released on NITRIC (https://www.nitrc.org/projects/brainstem_atlas/) and can be readily used by brain imaging researchers interested in studying brainstem pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

Brainstem involvement in subacute sclerosing panencephalitis.

PubMed

Sharma, Pawan; Singh, Dileep; Singh, Maneesh Kumar; Garg, Ravindra Kumar; Kohli, Neera

2011-01-01

The parieto-occipital region of the brain is most frequently and severely affected in subacute sclerosing panencephalitis (SSPE). The basal ganglia, cerebellum and corpus callosum are less commonly involved. Brainstem involvement is rarely described in SSPE, and usually there is involvement of other regions of the brain. We describe a patient with subacute sclerosing panencephalitis with brain magnetic resonance imaging showing extensive brainstem involvement without significant involvement of other cortical structures. Though rarely described in SSPE, one should be aware of such brainstem and cerebellum involvement, and SSPE should be kept in mind when brainstem signal changes are seen in brain MRI with or without involvement of other regions of brain to avoid erroneous reporting.

Longitudinal Development of Distortion Product Otoacoustic Emissions in Infants With Normal Hearing.

PubMed

Hunter, Lisa L; Blankenship, Chelsea M; Keefe, Douglas H; Feeney, M Patrick; Brown, David K; McCune, Annie; Fitzpatrick, Denis F; Lin, Li

2018-01-23

The purpose of this study was to describe normal characteristics of distortion product otoacoustic emission (DPOAE) signal and noise level in a group of newborns and infants with normal hearing followed longitudinally from birth to 15 months of age. This is a prospective, longitudinal study of 231 infants who passed newborn hearing screening and were verified to have normal hearing. Infants were enrolled from a well-baby nursery and two neonatal intensive care units (NICUs) in Cincinnati, OH. Normal hearing was confirmed with threshold auditory brainstem response and visual reinforcement audiometry. DPOAEs were measured in up to four study visits over the first year after birth. Stimulus frequencies f1 and f2 were used with f2/f1 = 1.22, and the DPOAE was recorded at frequency 2f1-f2. A longitudinal repeated-measure linear mixed model design was used to study changes in DPOAE level and noise level as related to age, middle ear transfer, race, and NICU history. Significant changes in the DPOAE and noise levels occurred from birth to 12 months of age. DPOAE levels were the highest at 1 month of age. The largest decrease in DPOAE level occurred between 1 and 5 months of age in the mid to high frequencies (2 to 8 kHz) with minimal changes occurring between 6, 9, and 12 months of age. The decrease in DPOAE level was significantly related to a decrease in wideband absorbance at the same f2 frequencies. DPOAE noise level increased only slightly with age over the first year with the highest noise levels in the 12-month-old age range. Minor, nonsystematic effects for NICU history, race, and gestational age at birth were found, thus these results were generalizable to commonly seen clinical populations. DPOAE levels were related to wideband middle ear absorbance changes in this large sample of infants confirmed to have normal hearing at auditory brainstem response and visual reinforcement audiometry testing. This normative database can be used to evaluate clinical results from birth to 1 year of age. The distributions of DPOAE level and signal to noise ratio data reported herein across frequency and age in normal-hearing infants who were healthy or had NICU histories may be helpful to detect the presence of hearing loss in infants.

Chloral hydrate sedation for auditory brainstem response (ABR) testing in children: Safety and effectiveness.

PubMed

Valenzuela, Dianne G; Kumar, Divjot Singh; Atkins, Cheryl Labelle; Beers, Alison; Kozak, Frederick K; Chadha, Neil K

2016-04-01

The auditory brainstem response (ABR) test is used to identify hearing loss and measure hearing thresholds of infants and children who cannot be tested using standard behavioral hearing testing methods. In order for the ABR to yield useful data, a child must be asleep throughout the duration of the test. In many centers, this is achieved through the use of a general anesthetic, with its inherent risks and costs. Since 2004, ABRs have been routinely conducted at BC Children's Hospital in an ambulatory care setting under oral chloral hydrate sedation, with monitoring by a specialist nurse. The aim of this retrospective study was to assess the effectiveness and safety of nurse-led sedation with chloral hydrate for ABR testing at our tertiary pediatric center. Medical and audiology records were reviewed for children aged 6 months to 17 years who underwent ABR testing from 2004 to 2012. We reviewed the dosage of drug used, condition of the child after chloral hydrate administration, adverse effects, audiological results, patients' vital signs, and the effectiveness of the sedative in keeping the child asleep throughout the duration of the test. Frequency distributions were derived for adverse outcomes. 725 ABR records encompassing 635 children (multiple ABR tests in some children) were reviewed. The average dose of chloral hydrate used was 52mg/kg. The majority of sedated ABR's (80.8%) were completed without any incident. Significant events [apnea and/or bradycardia], minor complications [vomiting, hypoxemia, prolonged sedation, and/or tachypnea] and restlessness were noted in 3.4%, 6.2%, and 5.0% of the cases, respectively. The majority of these issues resolved without medical intervention, such as the need to provide supplementary oxygen. In 95.9% of ABRs, chloral hydrate was successful in sedating the child adequately to answer the audiological question. This forms the largest study to date on oral sedation for ABR testing. Based on our results, the use of chloral hydrate in the presence of a sedation nurse was a safe and reliable method of performing ABR in infants and children. This may be of significant value to centres worldwide exploring alternatives to general anesthesia for ABR testing. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Brainstem cavernous malformations: anatomical, clinical, and surgical considerations.

PubMed

Giliberto, Giuliano; Lanzino, Desiree J; Diehn, Felix E; Factor, David; Flemming, Kelly D; Lanzino, Giuseppe

2010-09-01

Symptomatic brainstem cavernous malformations carry a high risk of permanent neurological deficit related to recurrent hemorrhage, which justifies aggressive management. Detailed knowledge of the microscopic and surface anatomy is important for understanding the clinical presentation, predicting possible surgical complications, and formulating an adequate surgical plan. In this article the authors review and illustrate the surgical and microscopic anatomy of the brainstem, provide anatomoclinical correlations, and illustrate a few clinical cases of cavernous malformations in the most common brainstem areas.

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

Gong, G; Liu, C; Liu, C

Purpose: To analyze the error in contouring the brainstem for patients with head and neck cancer who underwent radiotherapy based on computed tomography (CT) and magnetic resonance (MR) images. Methods: 20 brain tumor and 17 nasopharyngeal cancer patients were randomly selected. Each patient underwent MR and CT scanning. For each patient, one observer contoured the brainstem on CT and MR images for 10 times, and 10 observers from five centers delineated the brainstem on CT and MR images only one time. The inter- and intra-observers volume and outline variations were compared. Results: The volumes of brainstem contoured by inter- andmore » intra-observers on CT and MR images were similar (p>0.05). The reproducibility of contouring brainstem on MR images was better than that on CT images (p<0.05) for both inter- and intra-observer variability. The inter- and intra-observer for contouring on CT images reached mean values of 0.81±0.05 (p>0.05) and of 0.85±0.05 (p>0.05), respectively, while on MR images these respective values were 0.90±0.05 (p>0.05) and 0.92±0.04 (p>0.05). Conclusion: Contouring the brainstem on MR images was more accurate and reproducible than that on CT images. Precise information might be more helpful for protecting the brainstem radiation injury the patients whose lesion were closed to brainstem.« less

[Distribution of human enterovirus 71 in brainstem of infants with brain stem encephalitis and infection mechanism].

PubMed

Hao, Bo; Gao, Di; Tang, Da-Wei; Wang, Xiao-Guang; Liu, Shui-Ping; Kong, Xiao-Ping; Liu, Chao; Huang, Jing-Lu; Bi, Qi-Ming; Quan, Li; Luo, Bin

2012-04-01

To explore the mechanism that how human enterovirus 71 (EV71) invades the brainstem and how intercellular adhesion molecules-1 (ICAM-1) participates by analyzing the expression and distribution of human EV71, and ICAM-1 in brainstem of infants with brain stem encephalitis. Twenty-two brainstem of infants with brain stem encephalitis were collected as the experimental group and 10 brainstems of fatal congenital heart disease were selected as the control group. The sections with perivascular cuffings were selected to observe EV71-VP1 expression by immunohistochemistry method and ICAM-1 expression was detected for the sections with EV71-VP1 positive expression. The staining image analysis and statistics analysis were performed. The experiment and control groups were compared. (1) EV71-VP1 positive cells in the experimental group were mainly astrocytes in brainstem with nigger-brown particles, and the control group was negative. (2) ICAM-1 positive cells showed nigger-brown. The expression in inflammatory cells (around blood vessels of brain stem and in glial nodules) and gliocytes increased. The results showed statistical difference comparing with control group (P < 0.05). The brainstem encephalitis can be used to diagnose fatal EV71 infection in infants. EV71 can invade the brainstem via hematogenous route. ICAM-1 may play an important role in the pathogenic process.

Deviance detection based on regularity encoding along the auditory hierarchy: electrophysiological evidence in humans.

PubMed

Escera, Carles; Leung, Sumie; Grimm, Sabine

2014-07-01

Detection of changes in the acoustic environment is critical for survival, as it prevents missing potentially relevant events outside the focus of attention. In humans, deviance detection based on acoustic regularity encoding has been associated with a brain response derived from the human EEG, the mismatch negativity (MMN) auditory evoked potential, peaking at about 100-200 ms from deviance onset. By its long latency and cerebral generators, the cortical nature of both the processes of regularity encoding and deviance detection has been assumed. Yet, intracellular, extracellular, single-unit and local-field potential recordings in rats and cats have shown much earlier (circa 20-30 ms) and hierarchically lower (primary auditory cortex, medial geniculate body, inferior colliculus) deviance-related responses. Here, we review the recent evidence obtained with the complex auditory brainstem response (cABR), the middle latency response (MLR) and magnetoencephalography (MEG) demonstrating that human auditory deviance detection based on regularity encoding-rather than on refractoriness-occurs at latencies and in neural networks comparable to those revealed in animals. Specifically, encoding of simple acoustic-feature regularities and detection of corresponding deviance, such as an infrequent change in frequency or location, occur in the latency range of the MLR, in separate auditory cortical regions from those generating the MMN, and even at the level of human auditory brainstem. In contrast, violations of more complex regularities, such as those defined by the alternation of two different tones or by feature conjunctions (i.e., frequency and location) fail to elicit MLR correlates but elicit sizable MMNs. Altogether, these findings support the emerging view that deviance detection is a basic principle of the functional organization of the auditory system, and that regularity encoding and deviance detection is organized in ascending levels of complexity along the auditory pathway expanding from the brainstem up to higher-order areas of the cerebral cortex.

A new view of “dream enactment” in REM sleep behavior disorder

PubMed Central

Blumberg, Mark S.; Plumeau, Alan M.

2015-01-01

SUMMARY REM sleep behavior disorder (RBD) is a disorder in which patients exhibit increased muscle tone and exaggerated myoclonic twitching during REM sleep. In addition, violent movements of the limbs, and complex behaviors that can sometimes appear to involve the enactment of dreams, are associated with RBD. These behaviors are widely thought to result from a dysfunction involving atonia-producing neural circuitry in the brainstem, thereby unmasking cortically generated dreams. Here we scrutinize the assumptions that led to this interpretation of RBD. In particular, we challenge the assumption that motor cortex produces twitches during REM sleep, thus calling into question the related assumption that motor cortex is primarily responsible for all of the pathological movements of RBD. Moreover, motor cortex is not even necessary to produce complex behavior; for example, stimulation of some brainstem structures can produce defensive and aggressive behaviors in rats and monkeys that are striking similar to those reported in human patients with RBD. Accordingly, we suggest an interpretation of RBD that focuses increased attention on the brainstem as a source of the pathological movements and that considers sensory feedback from moving limbs as an important influence on the content of dream mentation. PMID:26802823

Brainstem auditory-evoked potentials as an objective tool for evaluating hearing dysfunction in traumatic brain injury.

PubMed

Lew, Henry L; Lee, Eun Ha; Miyoshi, Yasushi; Chang, Douglas G; Date, Elaine S; Jerger, James F

2004-03-01

Because of the violent nature of traumatic brain injury, traumatic brain injury patients are susceptible to various types of trauma involving the auditory system. We report a case of a 55-yr-old man who presented with communication problems after traumatic brain injury. Initial results from behavioral audiometry and Weber/Rinne tests were not reliable because of poor cooperation. He was transferred to our service for inpatient rehabilitation, where review of the initial head computed tomographic scan showed only left temporal bone fracture. Brainstem auditory-evoked potential was then performed to evaluate his hearing function. The results showed bilateral absence of auditory-evoked responses, which strongly suggested bilateral deafness. This finding led to a follow-up computed tomographic scan, with focus on bilateral temporal bones. A subtle transverse fracture of the right temporal bone was then detected, in addition to the left temporal bone fracture previously identified. Like children with hearing impairment, traumatic brain injury patients may not be able to verbalize their auditory deficits in a timely manner. If hearing loss is suspected in a patient who is unable to participate in traditional behavioral audiometric testing, brainstem auditory-evoked potential may be an option for evaluating hearing dysfunction.

Effect of edaravone on acute brainstem-cerebellar infarction with vertigo and sudden hearing loss.

PubMed

Inoue, Yuta; Yabe, Takao; Okada, Kazunari; Nakamura, Yuka

2014-06-01

We report 2 cases with acute brainstem and brainstem-cerebellar infarction showed improvement of their signs and symptoms after administration of edaravone. Case 1, a 74-year-old woman who experienced sudden vertigo, also had dysarthria and left hemiplegia. Magnetic resonance imaging (MRI) showed an abnormal region in the right ventrolateral medulla oblongata. The patient's vertigo and hemiplegia improved completely after treatment. Case 2, a 50-year-old man who experienced sudden vertigo and sensorineural hearing loss (SNHL), developed dysarthria after admission. MRI revealed acute infarction in the right cerebellar hemisphere. Magnetic resonance angiography revealed dissection of the basilar artery and occlusion of the right anterior inferior cerebellar artery. The patient's vertigo and hearing remarkably improved. We have described 2 patients whose early symptoms were vertigo and sudden SNHL, but who were later shown to have ischemic lesions of the central nervous system. Edaravone is neuroprotective drug with free radical-scavenging actions. Free radicals in the ear are responsible for ischemic damage. Edaravone, a free radical scavenger, may be useful in the treatment of vertigo and SNHL. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Brainstem auditory evoked potentials in children with lead exposure.

PubMed

Alvarenga, Katia de Freitas; Morata, Thais Catalani; Lopes, Andrea Cintra; Feniman, Mariza Ribeiro; Corteletti, Lilian Cassia Bornia Jacob

2015-01-01

Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months). The mean time-integrated cumulative blood lead index was 12 μg/dL (SD ± 5.7, range: 2.433). All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

The effect of preterm birth on brainstem, middle latency and cortical auditory evoked responses (BMC AERs).

PubMed

Pasman, J W; Rotteveel, J J; de Graaf, R; Stegeman, D F; Visco, Y M

1992-12-01

Recent studies on the maturation of auditory brainstem evoked responses (ABRs) present conflicting results, whereas only sparse reports exist with respect to the maturation of middle latency auditory evoked responses (MLRs) and auditory cortical evoked responses (ACRs). The present study reports the effect of preterm birth on the maturation of auditory evoked responses in low risk preterm infants (27-34 weeks conceptional age). The ABRs indicate a consistent trend towards longer latencies for all individual ABR components and towards longer interpeak latencies in preterm infants. The MLR shows longer latencies for early component P0 in preterm infants. The ACRs show a remarkable difference between preterm and term infants. At 40 weeks CA the latencies of ACR components Na and P2 are significantly longer in term infants, whereas at 52 weeks CA the latencies of the same ACR components are shorter in term infants. The results support the hypothesis that retarded myelination of the central auditory pathway is partially responsible for differences found between preterm infants and term infants with respect to late ABR components and early MLR component P0. Furthermore, mild conductive hearing loss in preterm infants may also play its role. A more complex mechanism is implicated to account for the findings noted with respect to MLR component Na and ACR components Na and P2.

The Brainstem Tau Cytoskeletal Pathology of Alzheimer's Disease: A Brief Historical Overview and Description of its Anatomical Distribution Pattern, Evolutional Features, Pathogenetic and Clinical Relevance.

PubMed

Rüb, Udo; Stratmann, Katharina; Heinsen, Helmut; Turco, Domenico Del; Seidel, Kay; Dunnen, Wilfred den; Korf, Horst-Werner

2016-01-01

The human brainstem is involved in the regulation of the sleep/waking cycle and normal sleep architectonics and is crucial for the performance of a variety of somatomotor, vital autonomic, oculomotor, vestibular, auditory, ingestive and somatosensory functions. It harbors the origins of the ascending dopaminergic, cholinergic, noradrenergic, serotonergic systems, as well the home base of the descending serotonergic system. In contrast to the cerebral cortex the affection of the brainstem in Alzheimer's disease (AD) by the neurofibrillary or tau cytoskeletal pathology was recognized only approximately fourty years ago in initial brainstem studies. Detailed pathoanatomical investigations of silver stained or tau immunostained brainstem tissue sections revealed nerve cell loss and prominent ADrelated cytoskeletal changes in the raphe nuclei, locus coeruleus, and in the compact parts of the substantia nigra and pedunculopontine nucleus. An additional conspicuous AD-related cytoskeletal pathology was also detected in the auditory brainstem system of AD patients (i.e. inferior colliculus, superior olive, dorsal cochlear nucleus), in the oculomotor brainstem network (i.e. rostral interstitial nucleus of the medial longitudinal fascicle, Edinger-Westphal nucleus, reticulotegmental nucleus of pons), autonomic system (i.e. central and periaqueductal grays, parabrachial nuclei, gigantocellular reticular nucleus, dorsal motor vagal and solitary nuclei, intermediate reticular zone). The alterations in these brainstem nuclei offered for the first time adequate explanations for a variety of less understood disease symptoms of AD patients: Parkinsonian extrapyramidal motor signs, depression, hallucinations, dysfunctions of the sleep/wake cycle, changes in sleeping patterns, attentional deficits, exaggerated pupil dilatation, autonomic dysfunctions, impairments of horizontal and vertical saccades, dysfunctional smooth pursuits. The very early occurrence of the AD-related cytoskeletal pathology in some of these brainstem nuclei points to a major and strategic role of the brainstem in the induction and brain spread of the AD-related cytoskeletal pathology.

Compound heterozygosity of the functionally null Cdh23(v-ngt) and hypomorphic Cdh23(ahl) alleles leads to early-onset progressive hearing loss in mice.

PubMed

Miyasaka, Yuki; Suzuki, Sari; Ohshiba, Yasuhiro; Watanabe, Kei; Sagara, Yoshihiko; Yasuda, Shumpei P; Matsuoka, Kunie; Shitara, Hiroshi; Yonekawa, Hiromichi; Kominami, Ryo; Kikkawa, Yoshiaki

2013-01-01

The waltzer (v) mouse mutant harbors a mutation in Cadherin 23 (Cdh23) and is a model for Usher syndrome type 1D, which is characterized by congenital deafness, vestibular dysfunction, and prepubertal onset of progressive retinitis pigmentosa. In mice, functionally null Cdh23 mutations affect stereociliary morphogenesis and the polarity of both cochlear and vestibular hair cells. In contrast, the murine Cdh23(ahl) allele, which harbors a hypomorphic mutation, causes an increase in susceptibility to age-related hearing loss in many inbred strains. We produced congenic mice by crossing mice carrying the v niigata (Cdh23(v-ngt)) null allele with mice carrying the hypomorphic Cdh23(ahl) allele on the C57BL/6J background, and we then analyzed the animals' balance and hearing phenotypes. Although the Cdh23(v-ngt/ahl) compound heterozygous mice exhibited normal vestibular function, their hearing ability was abnormal: the mice exhibited higher thresholds of auditory brainstem response (ABR) and rapid age-dependent elevation of ABR thresholds compared with Cdh23(ahl/ahl) homozygous mice. We found that the stereocilia developed normally but were progressively disrupted in Cdh23(v-ngt/ahl) mice. In hair cells, CDH23 localizes to the tip links of stereocilia, which are thought to gate the mechanoelectrical transduction channels in hair cells. We hypothesize that the reduction of Cdh23 gene dosage in Cdh23(v-ngt/ahl) mice leads to the degeneration of stereocilia, which consequently reduces tip link tension. These findings indicate that CDH23 plays an important role in the maintenance of tip links during the aging process.

Chronic depolarization enhances the trophic effects of BDNF in rescuing auditory neurons following a sensorineural hearing loss

PubMed Central

Shepherd, Robert K.; Coco, Anne; Epp, Stephanie B.; Crook, Jeremy M.

2007-01-01

The development and maintenance of spiral ganglion neurons (SGNs) appears to be supported by both neural activity and neurotrophins. Removal of this support leads to their gradual degeneration. Here, we examine whether the exogenous delivery of the neurotrophin brain-derived neurotrophic factor (BDNF) in concert with electrical stimulation (ES) provides a greater protective effect than delivery of BDNF alone in vivo. The left cochlea of profoundly deafened guinea pigs was implanted with an electrode array and drug delivery system. BDNF or artificial perilymph (AP) was delivered continuously for 28 days. ES induced neural activity in two cohorts (BDNF/ES and AP/ES) while control animals received BDNF or AP without ES (BDNF/- and AP/-). The right cochleae of each animal served as deafened untreated controls. Electrically-evoked auditory brainstem responses (EABRs) were recorded immediately following surgery and at completion of the drug delivery period. AP/ES and AP/- cohorts showed an increase in EABR threshold over the implantation period while both BDNF cohorts exhibited a reduction in threshold (P < 0.001, t-test). Changes in neural sensitivity were complemented by significant differences in both SGN survival and soma area. BDNF cohorts demonstrated a significant trophic or survival advantage and larger soma area compared with AP-treated and deafened control cochleae; this advantage was greatest in the base of the cochlea. Importantly, ES significantly enhanced the survival effects of BDNF throughout the majority of the cochlea (P < 0.05, Bonferroni's test), while there was no evidence of trophic support provided by ES alone. Co-treatment of SGNs with BDNF and ES provide a substantial functional and trophic advantage; this treatment may have important implications for neural prostheses. PMID:15844207

Abnormalities in auditory efferent activities in children with selective mutism.

PubMed

Muchnik, Chava; Ari-Even Roth, Daphne; Hildesheimer, Minka; Arie, Miri; Bar-Haim, Yair; Henkin, Yael

2013-01-01

Two efferent feedback pathways to the auditory periphery may play a role in monitoring self-vocalization: the middle-ear acoustic reflex (MEAR) and the medial olivocochlear bundle (MOCB) reflex. Since most studies regarding the role of auditory efferent activity during self-vocalization were conducted in animals, human data are scarce. The working premise of the current study was that selective mutism (SM), a rare psychiatric disorder characterized by consistent failure to speak in specific social situations despite the ability to speak normally in other situations, may serve as a human model for studying the potential involvement of auditory efferent activity during self-vocalization. For this purpose, auditory efferent function was assessed in a group of 31 children with SM and compared to that of a group of 31 normally developing control children (mean age 8.9 and 8.8 years, respectively). All children exhibited normal hearing thresholds and type A tympanograms. MEAR and MOCB functions were evaluated by means of acoustic reflex thresholds and decay functions and the suppression of transient-evoked otoacoustic emissions, respectively. Auditory afferent function was tested by means of auditory brainstem responses (ABR). Results indicated a significantly higher proportion of children with abnormal MEAR and MOCB function in the SM group (58.6 and 38%, respectively) compared to controls (9.7 and 8%, respectively). The prevalence of abnormal MEAR and/or MOCB function was significantly higher in the SM group (71%) compared to controls (16%). Intact afferent function manifested in normal absolute and interpeak latencies of ABR components in all children. The finding of aberrant efferent auditory function in a large proportion of children with SM provides further support for the notion that MEAR and MOCB may play a significant role in the process of self-vocalization. © 2013 S. Karger AG, Basel.

Mice deficient in H+-ATPase a4 subunit have severe hearing impairment associated with enlarged endolymphatic compartments within the inner ear

PubMed Central

Lorente-Cánovas, Beatriz; Ingham, Neil; Norgett, Elizabeth E.; Golder, Zoe J.; Karet Frankl, Fiona E.; Steel, Karen P.

2013-01-01

SUMMARY Mutations in the ATP6V0A4 gene lead to autosomal recessive distal renal tubular acidosis in patients, who often show sensorineural hearing impairment. A first Atp6v0a4 knockout mouse model that recapitulates the loss of H+-ATPase function seen in humans has been generated and recently reported (Norgett et al., 2012). Here, we present the first detailed analysis of the structure and function of the auditory system in Atp6v0a4−/− knockout mice. Measurements of the auditory brainstem response (ABR) showed significantly elevated thresholds in homozygous mutant mice, which indicate severe hearing impairment. Heterozygote thresholds were normal. Analysis of paint-filled inner ears and sections from E16.5 embryos revealed a marked expansion of cochlear and endolymphatic ducts in Atp6v0a4−/− mice. A regulatory link between Atp6v0a4, Foxi1 and Pds has been reported and we found that the endolymphatic sac of Atp6v0a4−/− mice expresses both Foxi1 and Pds, which suggests a downstream position of Atp6v0a4. These mutants also showed a lack of endocochlear potential, suggesting a functional defect of the stria vascularis on the lateral wall of the cochlear duct. However, the main K+ channels involved in the generation of endocochlear potential, Kcnj10 and Kcnq1, are strongly expressed in Atp6v0a4−/− mice. Our results lead to a better understanding of the role of this proton pump in hearing function. PMID:23065636

The ototoxic effect of boric acid solutions applied into the middle ear of guinea pigs.

PubMed

Oztürkcan, Sedat; Dündar, Riza; Katilmis, Hüseyin; Ilknur, Ali Ekber; Aktaş, Sinem; Haciömeroğlu, Senem

2009-05-01

This study analyzed the ototoxic effects of boric acid solutions. Boric acid solutions have been used as otologic preparations for many years. Boric acid is commonly found in solutions prepared with alcohol or distilled water but can also be found in a powder form. These preparations are used for both their antiseptic and acidic qualities in external and middle ear infections. We investigated the ototoxic effect of boric acid solutions on guinea pigs. We are unaware of any similar, previously published study of this subject in English. The study was conducted on 28 young albino guinea pigs. Prior to application of the boric acid solution under general anesthesia, an Auditory Brainstem Response (ABRs) test was applied to the right ear of the guinea pigs. Following the test, a perforation was created on the tympanic membrane of the right ear of each guinea pig and small gelfoam pieces were inserted into the perforated area. Test solutions were administered to the middle ear for 10 days by means of a transcanal route. Fifteen days after inserting the gelfoams in all of the guinea pigs, we anasthesized the guinea pigs and removed the gelfoams from the perforated region of the ear and then performed an ABRs on each guinea pig. The ABRs were within the normal range before the applications. After the application, no significant changes were detected in the ABRs thresholds in neither the saline group nor the group administered boric acid and distilled water solution; however, significant changes were detected in the ABRs thresholds of the Gentamicine and boric acid and alcohol solution groups. We believe that a 4% boric acid solution prepared with distilled water can be a more reliable preparation than a 4% boric acid solution prepared with alcohol.

Factors influencing the efficacy of round window dexamethasone protection of residual hearing post-cochlear implant surgery.

PubMed

Chang, Andrew; Eastwood, Hayden; Sly, David; James, David; Richardson, Rachael; O'Leary, Stephen

2009-09-01

To protect hearing in an experimental model of cochlear implantation by the application of dexamethasone to the round window prior to surgery. The present study examined the dosage and timing relationships required to optimise the hearing protection. Dexamethasone or saline (control) was absorbed into a pledget of the carboxymethylcellulose and hyaluronic acid and applied to the round window of the guinea pig prior to cochlear implantation. The treatment groups were 2% w/v dexamethasone for 30, 60 and 120min; 20% dexamethasone applied for 30min. Auditory sensitivity was determined pre-operatively, and at 1 week after surgery, with pure-tone auditory brainstem response audiometry (2-32kHz). Cochlear implantation was performed via a cochleostomy drilled into the basal turn of the cochlea, into which a miniature cochlear implant dummy electrode was inserted using soft-surgery techniques. ABR thresholds were elevated after cochlear implantation, maximally at 32kHz and to a lesser extent at lower frequencies. Thresholds were less elevated after dexamethasone treatment, and the hearing protection improved when 2% dexamethasone was applied to the round window for longer periods of time prior to implantation. The time that dexamethasone need be applied to achieve hearing protection could be reduced by increasing the concentration of steroid, with a 20% application for 30min achieving similar levels of protection to a 60min application of 2% dexamethasone. Hearing protection is improved by increasing the time that dexamethasone is applied to the round window prior to cochlear implantation, and the waiting time can be reduced by increasing the steroid concentration. These results suggest that the diffusion dexamethasone through the cochlea is the prime determinant of the extent of hearing protection.

Synaptic transmission and short-term plasticity at the calyx of Held synapse revealed by multielectrode array recordings.

PubMed

Haustein, Martin D; Reinert, Thomas; Warnatsch, Annika; Englitz, Bernhard; Dietz, Beatrice; Robitzki, Andrea; Rübsamen, Rudolf; Milenkovic, Ivan

2008-09-30

We assessed the potential of using multielectrode arrays (MEAs) to investigate several physiological properties of the calyx of Held synapse in the medial nucleus of the trapezoid body of gerbil. Due to the large size of the synapse, it became widely employed in studies on synaptic mechanisms. Electrical stimulation at the midline evoked a characteristic compound signal consisting of a presynaptic volley (C(1)) and a postsynaptic response (C(2)). The C(1) was blocked by tetrodotoxin, whilst the C(2) was blocked by perfusion of low Ca(2+) external solution, or the AMPA-R antagonists CNQX, and GYKI52466. NMDA-R blocker D-AP5, partially inhibited the postsynaptic response at P12, but showed no effect in P30 animals. The inhibitory effects of GABA or glycine on postsynaptic responses were reciprocal with regard to animal's maturity: GABA caused a pronounced reduction of C(2) amplitude in P20-22 animals, while glycine showed a stronger inhibition in P27-28 animals. Low-frequency super-threshold stimulation of the afferents induced facilitation of the postsynaptic C(2) amplitudes and only minor changes in temporal characteristics of the signals. At stimulation frequencies >200 Hz, however, significant depression occurs accompanied by increases in transmission delay and in the width of the postsynaptic response. This study suggests MEAs as a useful tool to study calyx of Held synapse by simultaneous recordings of pre- and postsynaptic elements of synaptically interconnected neurons in the auditory brainstem. Moreover, MEAs enable convenient analysis of activity-dependent depression and modulation of neuronal activity by glycine and GABA at later developmental stages not accessible to patch recordings.

Pharmacological and Morphological Evidence of AMPK-Mediated Energy Sensing in the Lower Brain Stem Ependymocytes to Control Reproduction in Female Rodents.

PubMed

Minabe, Shiori; Deura, Chikaya; Ikegami, Kana; Goto, Teppei; Sanbo, Makoto; Hirabayashi, Masumi; Inoue, Naoko; Uenoyama, Yoshihisa; Maeda, Kei-Ichiro; Tsukamura, Hiroko

2015-06-01

Ependymocytes are one of the energy-sensing cells that regulate animal reproduction through their responsiveness to changes in extracellular glucose levels and the expression of pancreatic-type glucokinase and glucose transporter 2, which play a critical role in sensing blood glucose levels in pancreatic β-cells. Molecular mechanisms underlying glucose sensing in the ependymocytes remain poorly understood. The AMP-activated protein kinase (AMPK), a serine/threonine kinase highly conserved in all eukaryotic cells, has been suggested to be an intracellular fuel gauge that detects cellular energy status. The present study aims to clarify the role AMPK of the lower brainstem ependymocytes has in sensing glucose levels to regulate reproductive functions. First, we will show that administration of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, an AMPK activator, into the 4th ventricle suppressed pulsatile LH release in female rats. Second, we will demonstrate the presence of AMPK catalytic subunit immunoreactivities in the rat lower brainstem ependymocytes. Third, transgenic mice were generated to visualize the ependymocytes with Venus, a green fluorescent protein, expressed under the control of the mouse vimentin promoter for further in vitro study. The Venus-labeled ependymocytes taken from the lower brainstem of transgenic mice revealed that AMPK activation by 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, an AMPK activator, increased in vitro intracellular calcium concentrations. Taken together, malnutrition-induced AMPK activation of ependymocytes of the lower brainstem might be involved in suppression of GnRH/LH release and then gonadal activities.

Pharmacological and Morphological Evidence of AMPK-Mediated Energy Sensing in the Lower Brain Stem Ependymocytes to Control Reproduction in Female Rodents

PubMed Central

Minabe, Shiori; Deura, Chikaya; Ikegami, Kana; Goto, Teppei; Sanbo, Makoto; Hirabayashi, Masumi; Inoue, Naoko; Uenoyama, Yoshihisa; Maeda, Kei-ichiro

2015-01-01

Ependymocytes are one of the energy-sensing cells that regulate animal reproduction through their responsiveness to changes in extracellular glucose levels and the expression of pancreatic-type glucokinase and glucose transporter 2, which play a critical role in sensing blood glucose levels in pancreatic β-cells. Molecular mechanisms underlying glucose sensing in the ependymocytes remain poorly understood. The AMP-activated protein kinase (AMPK), a serine/threonine kinase highly conserved in all eukaryotic cells, has been suggested to be an intracellular fuel gauge that detects cellular energy status. The present study aims to clarify the role AMPK of the lower brainstem ependymocytes has in sensing glucose levels to regulate reproductive functions. First, we will show that administration of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, an AMPK activator, into the 4th ventricle suppressed pulsatile LH release in female rats. Second, we will demonstrate the presence of AMPK catalytic subunit immunoreactivities in the rat lower brainstem ependymocytes. Third, transgenic mice were generated to visualize the ependymocytes with Venus, a green fluorescent protein, expressed under the control of the mouse vimentin promoter for further in vitro study. The Venus-labeled ependymocytes taken from the lower brainstem of transgenic mice revealed that AMPK activation by 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, an AMPK activator, increased in vitro intracellular calcium concentrations. Taken together, malnutrition-induced AMPK activation of ependymocytes of the lower brainstem might be involved in suppression of GnRH/LH release and then gonadal activities. PMID:25822714

Management of a severe forceful breather with Rett syndrome using carbogen.

PubMed

Smeets, Eric E J; Julu, Peter O O; van Waardenburg, Dick; Engerström, Ingegerd Witt; Hansen, Stig; Apartopoulos, Flora; Curfs, Leopold M G; Schrander-Stumpel, Connie T R M

2006-11-01

We have used a novel neurophysiological technique in the NeuroScope system in combination with conventional electroencephalography (EEG) to monitor both brainstem and cortical activity simultaneously in real-time in a girl with Rett syndrome. The presenting clinical features in our patient were severe sleep disturbances, irregular breathing in the awake state dominated by Valsalva's type of breathing followed by tachypnoea and very frequent attacks of seizures and vacant spells. Our novel neurophysiological data showed that the patient was a Forceful Breather according to the breathing categories in Rett syndrome. She had frequent abnormal spontaneous brainstem activation (ASBA) preceded by severe attacks of hypocapnoea, which was caused by a combination of Valsalva's type of breathing and tachypnoea and all these together were responsible for the seizures and non-epileptic vacant spells. The ASBA was not detectable in conventional EEG and there were no epileptiform changes in the EEG during the seizures and vacant spells caused by the hypocapnic attacks, therefore these were pseudo-seizures. The record of brainstem activity confirmed that these were autonomic events, a kind of "brainstem epilepsy". We successfully treated the sleep disturbance with Pipamperone, a 5-hydroxytryptophan antagonist of receptor type 2 and we prevented the severe hypocapnoea during Valsalva's type of breathing and during tachypnoea using carbogen (a mixture of 5% carbon dioxide and 95% oxygen), which we gave by inhalation. Our treatment drastically reduced the autonomic events, promoted whole night sleep and significantly improved the quality of life in our patient. She can now participate in normal family activity which was previously impossible before treatment.

Cortico-fugal output from visual cortex promotes plasticity of innate motor behaviour.

PubMed

Liu, Bao-Hua; Huberman, Andrew D; Scanziani, Massimo

2016-10-20

The mammalian visual cortex massively innervates the brainstem, a phylogenetically older structure, via cortico-fugal axonal projections. Many cortico-fugal projections target brainstem nuclei that mediate innate motor behaviours, but the function of these projections remains poorly understood. A prime example of such behaviours is the optokinetic reflex (OKR), an innate eye movement mediated by the brainstem accessory optic system, that stabilizes images on the retina as the animal moves through the environment and is thus crucial for vision. The OKR is plastic, allowing the amplitude of this reflex to be adaptively adjusted relative to other oculomotor reflexes and thereby ensuring image stability throughout life. Although the plasticity of the OKR is thought to involve subcortical structures such as the cerebellum and vestibular nuclei, cortical lesions have suggested that the visual cortex might also be involved. Here we show that projections from the mouse visual cortex to the accessory optic system promote the adaptive plasticity of the OKR. OKR potentiation, a compensatory plastic increase in the amplitude of the OKR in response to vestibular impairment, is diminished by silencing visual cortex. Furthermore, targeted ablation of a sparse population of cortico-fugal neurons that specifically project to the accessory optic system severely impairs OKR potentiation. Finally, OKR potentiation results from an enhanced drive exerted by the visual cortex onto the accessory optic system. Thus, cortico-fugal projections to the brainstem enable the visual cortex, an area that has been principally studied for its sensory processing function, to plastically adapt the execution of innate motor behaviours.

Plasticity in the adult human auditory brainstem following short-term linguistic training

PubMed Central

Song, Judy H.; Skoe, Erika; Wong, Patrick C. M.; Kraus, Nina

2009-01-01

Peripheral and central structures along the auditory pathway contribute to speech processing and learning. However, because speech requires the use of functionally and acoustically complex sounds which necessitates high sensory and cognitive demands, long-term exposure and experience using these sounds is often attributed to the neocortex with little emphasis placed on subcortical structures. The present study examines changes in the auditory brainstem, specifically the frequency following response (FFR), as native English-speaking adults learn to incorporate foreign speech sounds (lexical pitch patterns) in word identification. The FFR presumably originates from the auditory midbrain, and can be elicited pre-attentively. We measured FFRs to the trained pitch patterns before and after training. Measures of pitch-tracking were then derived from the FFR signals. We found increased accuracy in pitch-tracking after training, including a decrease in the number of pitch-tracking errors and a refinement in the energy devoted to encoding pitch. Most interestingly, this change in pitch-tracking accuracy only occurred in the most acoustically complex pitch contour (dipping contour), which is also the least familiar to our English-speaking subjects. These results not only demonstrate the contribution of the brainstem in language learning and its plasticity in adulthood, but they also demonstrate the specificity of this contribution (i.e., changes in encoding only occurs in specific, least familiar stimuli, not all stimuli). Our findings complement existing data showing cortical changes after second language learning, and are consistent with models suggesting that brainstem changes resulting from perceptual learning are most apparent when acuity in encoding is most needed. PMID:18370594

Spinal and pontine relay pathways mediating respiratory rhythm entrainment by limb proprioceptive inputs in the neonatal rat.

PubMed

Giraudin, Aurore; Le Bon-Jégo, Morgane; Cabirol, Marie-Jeanne; Simmers, John; Morin, Didier

2012-08-22

The coordination of locomotion and respiration is widespread among mammals, although the underlying neural mechanisms are still only partially understood. It was previously found in neonatal rat that cyclic electrical stimulation of spinal cervical and lumbar dorsal roots (DRs) can fully entrain (1:1 coupling) spontaneous respiratory activity expressed by the isolated brainstem/spinal cord. Here, we used a variety of preparations to determine the type of spinal sensory inputs responsible for this respiratory rhythm entrainment, and to establish the extent to which limb movement-activated feedback influences the medullary respiratory networks via direct or relayed ascending pathways. During in vivo overground locomotion, respiratory rhythm slowed and became coupled 1:1 with locomotion. In hindlimb-attached semi-isolated preparations, passive flexion-extension movements applied to a single hindlimb led to entrainment of fictive respiratory rhythmicity recorded in phrenic motoneurons, indicating that the recruitment of limb proprioceptive afferents could participate in the locomotor-respiratory coupling. Furthermore, in correspondence with the regionalization of spinal locomotor rhythm-generating circuitry, the stimulation of DRs at different segmental levels in isolated preparations revealed that cervical and lumbosacral proprioceptive inputs are more effective in this entraining influence than thoracic afferent pathways. Finally, blocking spinal synaptic transmission and using a combination of electrophysiology, calcium imaging and specific brainstem lesioning indicated that the ascending entraining signals from the cervical or lumbar limb afferents are transmitted across first-order synapses, probably monosynaptic, in the spinal cord. They are then conveyed to the brainstem respiratory centers via a brainstem pontine relay located in the parabrachial/Kölliker-Fuse nuclear complex.

The relationship of age, gender, and IQ with the brainstem and thalamus in healthy children and adolescents: a magnetic resonance imaging volumetric study

PubMed Central

Xie, Yuhuan; Chen, Yian Ann; De Bellis, Michael D.

2011-01-01

In healthy children, there is a paucity of information on the growth of the brainstem and thalamus measured by anatomical magnetic resonance imaging. The relationships of age, gender, and age by gender with brainstem and thalamus volumes were analyzed from magnetic resonance brain images of 122 healthy children and adolescents (62 males, 60 females; ages four to seventeen). Results showed that age is a significant predictor of brainstem and thalamus volumes. The volume of the brainstem increases with age, while thalamus volume declines with age. The volumes of right thalami are significantly larger than that of left in both genders with greater rightward asymmetry and greater thalamus/grey matter ratio in females. Males have larger brainstems, but these differences are not significant when covarying for cerebral volumes. Larger thalami were associated with higher verbal IQ. This normative pediatric data is of value to researchers who study these regions in neurodevelopmental disorders. PMID:21954432

The relationship of age, gender, and IQ with the brainstem and thalamus in healthy children and adolescents: a magnetic resonance imaging volumetric study.

PubMed

Xie, Yuhuan; Chen, Yian Ann; De Bellis, Michael D

2012-03-01

In healthy children, there is a paucity of information on the growth of the brainstem and thalamus measured anatomically magnetic resonance imaging. The relations of age, gender, and age by gender with brainstem and thalamus volumes were analyzed from magnetic resonance brain images of 122 healthy children and adolescents (62 males, 60 females; ages 4 to 17). Results showed that age is a significant predictor of brainstem and thalamus volumes. The volume of the brainstem increases with age, while thalamus volume declines with age. The volume of the right thalamus is significantly larger than that of the left in both genders, with greater rightward asymmetry and greater thalamus to grey matter ratio in females. Males have larger brainstems, but these differences are not significant when covarying for cerebral volume. Larger thalami were associated with higher Verbal IQ. These normative pediatric data are of value to researchers who study these regions in neurodevelopmental disorders.

Dorsally exophytic glioblastoma arising from the medulla oblongata in an adult presenting as 4th ventricular mass.

PubMed

Das, Kuntal Kanti; Bettaswamy, Guru Prasad; Mehrotra, Anant; Jaiswal, Sushila; Jaiswal, Awadhesh Kumar; Behari, Sanjay

2017-01-01

Brainstem gliomas are relatively rare in adults (<2% of all gliomas). Exophytic gliomas are focal brainstem lesions, which project into the 4 th ventricle or cerebellopontine angles. These exophytic lesions are usually of low-grade histology (pilocytic astrocytoma or ganglioglioma) and have a relatively better outcome compared with brainstem gliomas as a whole. Glioblastoma is the commonest primary glial cell neoplasm and mostly occurs in the supratentorial compartment. It is rather uncommon in the brainstem and seldom has been described as having an exophytic growth pattern. Here we describe an exophytic brainstem glioblastoma arising from the medulla oblongata in a 55-year-old lady who presented with a 4 th ventricular mass, and present a brief review of the literature. Till now, six cases of glioblastoma arising from the medulla oblongata have been reported. So, ours is the seventh such report. To the best of our knowledge, it also happens to be the sixth reported case of dorsally exophytic brainstem glioblastoma till date.

Early spinal cord and brainstem involvement in infantile Leigh syndrome possibly caused by a novel variant.

PubMed

Tenney, Jeffrey R; Prada, Carlos E; Hopkin, Robert J; Hallinan, Barbara E

2013-12-01

Leigh syndrome, due to a dysfunction of mitochondrial energy metabolism, is a genetically heterogeneous and progressive neurologic disorder that usually occurs in infancy and childhood. Its clinical presentation and neuroimaging findings can be variable, especially early in the course of the disease. This report presents a patient with infantile Leigh syndrome who had atypical radiologic findings on serial neuroimaging studies with early and severe involvement of the cervical spinal cord and brainstem and injury to the thalami and basal ganglia occurring only late in the clinical course. Postmortem microscopic examination supported this timing of injury within the central nervous system. In addition, mitochondrial deoxyribonucleic acid sequencing showed a novel homoplasmic variant that could be responsible for this unique lethal form of Leigh syndrome.

Feasibility of creating a high-resolution 3D diffusion tensor imaging based atlas of the human brainstem: A case study at 11.7T

PubMed Central

Aggarwal, Manisha; Zhang, Jiangyang; Pletnikova, Olga; Crain, Barbara; Troncoso, Juan; Mori, Susumu

2013-01-01

A three-dimensional stereotaxic atlas of the human brainstem based on high resolution ex vivo diffusion tensor imaging (DTI) is introduced. The atlas consists of high resolution (125–255 μm isotropic) three-dimensional DT images of the formalin-fixed brainstem acquired at 11.7T. The DTI data revealed microscopic neuroanatomical details, allowing three-dimensional visualization and reconstruction of fiber pathways including the decussation of the pyramidal tract fibers, and interdigitating fascicles of the corticospinal and transverse pontine fibers. Additionally, strong grey-white matter contrasts in the apparent diffusion coefficient (ADC) maps enabled precise delineation of grey matter nuclei in the brainstem, including the cranial nerve and the inferior olivary nuclei. Comparison with myelin-stained histology shows that at the level of resolution achieved in this study, the structural details resolved with DTI contrasts in the brainstem were comparable to anatomical delineation obtained with histological sectioning. Major neural structures delineated from DTI contrasts in the brainstem are segmented and three-dimensionally reconstructed. Further, the ex vivo DTI data are nonlinearly mapped to a widely-used in vivo human brain atlas, to construct a high-resolution atlas of the brainstem in the Montreal Neurological Institute (MNI) stereotaxic coordinate space. The results demonstrate the feasibility of developing a 3D DTI based atlas for detailed characterization of brainstem neuroanatomy with high resolution and contrasts, which will be a useful resource for research and clinical applications. PMID:23384518

The Structural Connectome of the Human Central Homeostatic Network.

PubMed

Edlow, Brian L; McNab, Jennifer A; Witzel, Thomas; Kinney, Hannah C

2016-04-01

Homeostatic adaptations to stress are regulated by interactions between the brainstem and regions of the forebrain, including limbic sites related to respiratory, autonomic, affective, and cognitive processing. Neuroanatomic connections between these homeostatic regions, however, have not been thoroughly identified in the human brain. In this study, we perform diffusion spectrum imaging tractography using the MGH-USC Connectome MRI scanner to visualize structural connections in the human brain linking autonomic and cardiorespiratory nuclei in the midbrain, pons, and medulla oblongata with forebrain sites critical to homeostatic control. Probabilistic tractography analyses in six healthy adults revealed connections between six brainstem nuclei and seven forebrain regions, several over long distances between the caudal medulla and cerebral cortex. The strongest evidence for brainstem-homeostatic forebrain connectivity in this study was between the brainstem midline raphe and the medial temporal lobe. The subiculum and amygdala were the sampled forebrain nodes with the most extensive brainstem connections. Within the human brainstem-homeostatic forebrain connectome, we observed that a lateral forebrain bundle, whose connectivity is distinct from that of rodents and nonhuman primates, is the primary conduit for connections between the brainstem and medial temporal lobe. This study supports the concept that interconnected brainstem and forebrain nodes form an integrated central homeostatic network (CHN) in the human brain. Our findings provide an initial foundation for elucidating the neuroanatomic basis of homeostasis in the normal human brain, as well as for mapping CHN disconnections in patients with disorders of homeostasis, including sudden and unexpected death, and epilepsy.

Screening Procedures Used to Identify Children with Hearing Loss.

ERIC Educational Resources Information Center

Barringer, Donald G.; And Others

1993-01-01

Analysis of data on 1,404 young children with hearing losses indicated that 80% of the children were identified via informal hearing-screening procedures, such as parental suspicion and referral. Auditory brainstem response technology provided the lowest mean identification age. The study concludes that formal screening programs are not locating…

POSSIBLE ROLE OF THE BRAINSTEM IN THE MEDIATION OF PREPULSE INHIBITION IN THE RAT (JOURNAL VERSION)

EPA Science Inventory

Bilateral stimulation of electrodes aimed at the cuneiform nucleus produced significant inhibition of the startle response produced by presentation of an 8 KHz, 110 dB tone. Stimulation of electrodes aimed at the deep mesencephalic nucleus also reduced the magnitude of the startl...

Auditory brainstem response to complex sounds: a tutorial

PubMed Central

Skoe, Erika; Kraus, Nina

2010-01-01

This tutorial provides a comprehensive overview of the methodological approach to collecting and analyzing auditory brainstem responses to complex sounds (cABRs). cABRs provide a window into how behaviorally relevant sounds such as speech and music are processed in the brain. Because temporal and spectral characteristics of sounds are preserved in this subcortical response, cABRs can be used to assess specific impairments and enhancements in auditory processing. Notably, subcortical function is neither passive nor hardwired but dynamically interacts with higher-level cognitive processes to refine how sounds are transcribed into neural code. This experience-dependent plasticity, which can occur on a number of time scales (e.g., life-long experience with speech or music, short-term auditory training, online auditory processing), helps shape sensory perception. Thus, by being an objective and non-invasive means for examining cognitive function and experience-dependent processes in sensory activity, cABRs have considerable utility in the study of populations where auditory function is of interest (e.g., auditory experts such as musicians, persons with hearing loss, auditory processing and language disorders). This tutorial is intended for clinicians and researchers seeking to integrate cABRs into their clinical and/or research programs. PMID:20084007

Combining Use of Captopril and Losartan Attenuates the Progress of Streptococcus pneumoniae-Induced Tympanosclerosis through the Suppression of TGF-β1 Expression

PubMed Central

Yan, Wenqing; Li, Jianfeng; Chai, Renjie; Guo, Wentao; Xu, Lei; Han, Yuechen; Bai, Xiaohui; Wang, Haibo

2014-01-01

Objectives In this study, using an Streptococcus pneumoniae-induced tympanosclerosis (TS) model, we explored the effects of captopril and losartan in the treatment of TS and the possible mechanisms. Study Design A prospective experimental animal study. Methods We set up the TS models in both guinea pig and wistar rat by inoculation of type-3 Streptococcus pneumoniae microorganisms and then treated the animals with the combining use of captopril and losartan. Otomicroscopy was employed to observe the development of TS. Auditory brainstem response was used to test the hearing function of animals. Hematoxylin-eosin and von Kossa staining were performed to determine the morphological changes and calcium depositions. The protein expressions of transforming growth factor β1 (TGF-β1) were assessed by western blot and immunohistochemistry staining, and the mRNA level of TGF-β1 was measured by quantitative reverse transcription- polymerase chain reaction. Results The combining use of captopril and losartan attenuated TS responses in terms of a decrease in the TS incidence and the ABR threshold, a reduction of hyalinization and calcification in the middle ear mucosa and the thickness of the mucosa. In addition, the TGF-β1 expression was decreased at both protein and mRNA levels. Conclusion Our data indicate, for the first time, that the combining use of captopril and losartan obviously attenuates TS progress through inhibiting the overexpressing of TGF-β1. PMID:25360706

Responses evoked from man by acoustic stimulation

NASA Technical Reports Server (NTRS)

Galambos, R.; Hecox, K.; Picton, T.

1974-01-01

Clicks and other acoustic stimuli evoke time-locked responses from the brain of man. The properties of the waves recordable within the interval from 1 to 10 msec after the stimuli strike the eardrum are discussed along with factors influencing the waves in the 100 to 500 msec epoch. So-called brainstem responses from a normal young adult are considered. No waves were observed for clicks to weak to be heard. With increasing stimulus strength the waves become larger in amplitude and their latency shortens.

Brainstem Auditory Evoked Potential Study in Children with Autistic Disorder.

ERIC Educational Resources Information Center

Wong, Virginia; Wong, Sik Nin

1991-01-01

Brainstem auditory evoked potentials were compared in 109 children with infantile autism, 38 with autistic condition, 19 with mental retardation, and 20 normal children. Children with infantile autism or autistic condition had significantly longer brainstem transmission time than normal children suggesting neurological damage as the basis of…

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

Mayo, Charles, E-mail: charles.mayo@umassmemorial.or; Yorke, Ellen; Merchant, Thomas E.

Publications relating brainstem radiation toxicity to quantitative dose and dose-volume measures derived from three-dimensional treatment planning were reviewed. Despite the clinical importance of brainstem toxicity, most studies reporting brainstem effects after irradiation have fewer than 100 patients. There is limited evidence relating toxicity to small volumes receiving doses above 60-64 Gy using conventional fractionation and no definitive criteria regarding more subtle dose-volume effects or effects after hypofractionated treatment. On the basis of the available data, the entire brainstem may be treated to 54 Gy using conventional fractionation using photons with limited risk of severe or permanent neurological effects. Smaller volumesmore » of the brainstem (1-10 mL) may be irradiated to maximum doses of 59 Gy for dose fractions <=2 Gy; however, the risk appears to increase markedly at doses >64 Gy.« less

Auditory Brainstem and Middle Latency Responses Measured Pre- and Posttreatment for Hyperacusic Hearing-Impaired Persons Successfully Treated to Improve Sound Tolerance and to Expand the Dynamic Range for Loudness: Case Evidence.

PubMed

Formby, Craig; Korczak, Peggy; Sherlock, LaGuinn P; Hawley, Monica L; Gold, Susan

2017-02-01

In this report of three cases, we consider electrophysiologic measures from three hyperacusic hearing-impaired individuals who, prior to treatment to expand their dynamic ranges for loudness, were problematic hearing aid candidates because of their diminished sound tolerance and reduced dynamic ranges. Two of these individuals were treated with structured counseling combined with low-level broadband sound therapy from bilateral sound generators and the third case received structured counseling in combination with a short-acting placebo sound therapy. Each individual was highly responsive to his or her assigned treatment as revealed by expansion of the dynamic range by at least 20 dB at one or more frequencies posttreatment. Of specific interest in this report are their latency and amplitude measures taken from tone burst-evoked auditory brainstem response (ABR) and cortically derived middle latency response (MLR) recordings, measured as a function of increasing loudness at 500 and 2,000 Hz pre- and posttreatment. The resulting ABR and MLR latency and amplitude measures for each case are considered here in terms of pre- and posttreatment predictions. The respective pre- and posttreatment predictions anticipated larger pretreatment response amplitudes and shorter pretreatment response latencies relative to typical normal control values and smaller normative-like posttreatment response amplitudes and longer posttreatment response latencies relative to the corresponding pretreatment values for each individual. From these results and predictions, we conjecture about the neural origins of the hyperacusis conditions (i.e., brainstem versus cortical) and the neuronal sites responsive to treatment. The only consistent finding in support of the pre- and posttreatment predictions and, thus, the strongest index of hyperacusis and positive treatment-related effects was measured for MLR latency responses for wave Pa at 2,000 Hz. Other response indices, including ABR wave V latency and wave V-V' amplitude and MLR wave Na-Pa amplitude for 500 and 2,000 Hz, appear either ambiguous across and/or within these individuals. Notwithstanding significant challenges for interpreting these findings, including associated confounding effects of their sensorineural hearing losses and differences in the presentation levels of the toneburst stimuli used to collect these measures for each individual, our limited analyses of three cases suggest measures of MLR wave Pa latency at 2,000 Hz (reflecting cortical contributions) may be a promising objective indicator of hyperacusis and dynamic range expansion treatment effects.

Linear summation in the barn owl's brainstem underlies responses to interaural time differences.

PubMed

Kuokkanen, Paula T; Ashida, Go; Carr, Catherine E; Wagner, Hermann; Kempter, Richard

2013-07-01

The neurophonic potential is a synchronized frequency-following extracellular field potential that can be recorded in the nucleus laminaris (NL) in the brainstem of the barn owl. Putative generators of the neurophonic are the afferent axons from the nucleus magnocellularis, synapses onto NL neurons, and spikes of NL neurons. The outputs of NL, i.e., action potentials of NL neurons, are only weakly represented in the neurophonic. Instead, the inputs to NL, i.e., afferent axons and their synaptic potentials, are the predominant origin of the neurophonic (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274-2290, 2010). Thus in NL the monaural inputs from the two brain sides converge and create a binaural neurophonic. If these monaural inputs contribute independently to the extracellular field, the response to binaural stimulation can be predicted from the sum of the responses to ipsi- and contralateral stimulation. We found that a linear summation model explains the dependence of the responses on interaural time difference as measured experimentally with binaural stimulation. The fit between model predictions and data was excellent, even without taking into account the nonlinear responses of NL coincidence detector neurons, although their firing rate and synchrony strongly depend on the interaural time difference. These results are consistent with the view that the afferent axons and their synaptic potentials in NL are the primary origin of the neurophonic.

Neural Timing is Linked to Speech Perception in Noise

PubMed Central

Samira, Anderson; Erika, Skoe; Bharath, Chandrasekaran; Nina, Kraus

2010-01-01

Understanding speech in background noise is challenging for every listener, including those with normal peripheral hearing. This difficulty is due in part to the disruptive effects of noise on neural synchrony, resulting in degraded representation of speech at cortical and subcortical levels as reflected by electrophysiological responses. These problems are especially pronounced in clinical populations such as children with learning impairments. Given the established effects of noise on evoked responses, we hypothesized that listening-in-noise problems are associated with degraded processing of timing information at the brainstem level. Participants (66 children, ages 8 to 14 years, 22 females) were divided into groups based on their performance on clinical measures of speech-in-noise perception (SIN) and reading. We compared brainstem responses to speech syllables between top and bottom SIN and reading groups in the presence and absence of competing multi-talker babble. In the quiet condition, neural response timing was equivalent between groups. In noise, however, the bottom groups exhibited greater neural delays relative to the top groups. Group-specific timing delays occurred exclusively in response to the noise-vulnerable formant transition, not to the more perceptually-robust, steady-state portion of the stimulus. These results demonstrate that neural timing is disrupted by background noise and that greater disruptions are associated with the inability to perceive speech in challenging listening conditions. PMID:20371812

Overactive bladder and pontine reticular formation.

PubMed

Zorba, Orhan Ünal; Kırbaş, Serkan; Uzun, Hakkı; Cetinkaya, Mehmet; Önem, Kadir; Rifaioğlu, Mehmet Murat

2013-01-01

The etiology of overactive bladder (OAB) remains unclear. Observed neurogenic factors in the literature are limited to suprapontine or spinal pathologies. The blink reflex is a useful tool in the evaluation of brainstem functions. Blink reflex latency times were evaluated in order to reveal pathology in the brainstem. A total of 60 women, 30 patients with idiopathic OAB and 30 healthy controls, were enrolled in the study. Blink reflex latency times were analyzed by electrical stimulation of the supraorbital nerve. Two responses in the orbicularis oculi muscle, early ipsilateral response (R1) and late bilateral response (R2) latency times, were recorded. Mean ages of the patients and controls were 51.9 ± 5.3 and 49.2 ± 6.2 years, respectively. R2 latency times were significantly higher in patients than in controls. However, R1 latency times were similar between the two groups. The results of the study suggest a significant relation between late blink latency times and OAB. An oligosynaptic path via the trigeminal nuclei is responsible for R1; however, R2 response is relayed through the reticular formation. Stimulation of pontine reticular formation inhibits micturition contraction. In some patients, idiopathic OAB may result from reticular formation-originated pathology. Additional studies on other reticular formation-mediated reflexes are needed to reveal possible dysfunction of reticular formation. Copyright © 2013 S. Karger AG, Basel.

Hydrogen-rich saline alleviates experimental noise-induced hearing loss in guinea pigs.

PubMed

Zhou, Y; Zheng, H; Ruan, F; Chen, X; Zheng, G; Kang, M; Zhang, Q; Sun, X

2012-05-03

To examine the efficiency of hydrogen-rich saline in the treatment of intensive noise-induced cochlear injury. Forty guinea pigs were assigned to one of four groups: HS+NOISE (i.p. injection hydrogen-rich saline), NS+NOISE (i.p. injection normal saline), NOISE ALONE (noise control), and NO TREATMENT (normal control) groups. The HS+NOISE, NS+NOISE, and NOISE ALONE groups were exposed to intensive noise (4 h at 115 dB SPL noise of 4000±100 Hz). The auditory brainstem response (ABR) was used to examine the hearing threshold in each group. Distortion product otoacoustic emission (DPOAE) was used to examine outer hair cell function. We also examined cochlear morphology to evaluate inner and outer hair cell trauma induced by noise exposure. Hydrogen-rich saline was administered twice daily for 6 days (2.5 ml/kg, i.p.) 24 h after noise exposure. Baseline ABR thresholds and DPOAE values were normal in all groups at the measured frequencies (2, 4, 8, and 16 kHz) before noise exposure. The ABR threshold shift was 50-55 dB across the frequencies tested, and average DPOAE declined in the NOISE ALONE, NS+NOISE, and HS+NOISE groups 24 h after noise exposure. However, the changes in cochlear parameters were different between groups. The HS+NOISE group showed a significantly decreased ABR threshold value as compared with the NS+NOISE or NOISE ALONE group (P<0.01) on day 7. The mean DPOAE recovered to some extent in the three noise exposure groups, but at most frequencies the HS+NOISE group showed significantly increased DPOAE on day 7 as compared with the NS+NOISE group or NOISE ALONE group (P<0.01). Surface Corti organ preparations stained with succinate dehydrogenase (SDH) showed that most outer hair cells (OHCs) were still dropsical and a few were missing 7 days after noise exposure in the NS+NOISE group. Only a few OHCs were slightly dropsical in the HS+NOISE group. The numbers of missing hair cells 7 days after noise exposure were significantly greater in the NOISE ONLY and NS+NOISE groups than the HS+NOISE group (P<0.01). Hydrogen-rich saline can alleviate experimental noise-induced hearing loss in guinea pigs, partially by preventing the death of cochlear hair cells after intensive noise exposure. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Methionine Sulfoxide Reductase A Knockout Mice Show Progressive Hearing Loss and Sensitivity to Acoustic Trauma.

PubMed

Alqudah, Safa; Chertoff, Mark; Durham, Dianne; Moskovitz, Jackob; Staecker, Hinrich; Peppi, Marcello

2018-06-21

Methionine sulfoxide reductases (MsrA and MsrB) protect the biological activity of proteins from oxidative modifications to methionine residues and are important for protecting against the pathological effects of neurodegenerative diseases. In the current study, we characterized the auditory phenotype of the MsrA knockout mouse. Young MsrA knockout mice showed small high-frequency threshold elevations for auditory brainstem response and distortion product otoacoustic emission compared to those of wild-type mice, which progressively worsened in older MsrA knockout mice. MsrA knockout mice showed an increased sensitivity to noise at young and older ages, suggesting that MsrA is part of a mechanism that protects the cochlea from acoustic damage. MsrA mRNA in the cochlea was increased following acoustic stimulation. Finally, expression of mRNA MsrB1 was compromised at 6 months old, but not in younger MsrA knockout mice (compared to controls). The identification of MsrA in the cochlea as a protective mediator from both early onset hearing loss and acoustic trauma expands our understanding of the pathways that may induce protection from acoustic trauma and foster further studies on how to prevent the damaging effect of noise exposure through Msr-based therapy. © 2018 S. Karger AG, Basel.

Blast-Induced Tinnitus and Elevated Central Auditory and Limbic Activity in Rats: A Manganese-Enhanced MRI and Behavioral Study.

PubMed

Ouyang, Jessica; Pace, Edward; Lepczyk, Laura; Kaufman, Michael; Zhang, Jessica; Perrine, Shane A; Zhang, Jinsheng

2017-07-07

Blast-induced tinitus is the number one service-connected disability that currently affects military personnel and veterans. To elucidate its underlying mechanisms, we subjected 13 Sprague Dawley adult rats to unilateral 14 psi blast exposure to induce tinnitus and measured auditory and limbic brain activity using manganese-enhanced MRI (MEMRI). Tinnitus was evaluated with a gap detection acoustic startle reflex paradigm, while hearing status was assessed with prepulse inhibition (PPI) and auditory brainstem responses (ABRs). Both anxiety and cognitive functioning were assessed using elevated plus maze and Morris water maze, respectively. Five weeks after blast exposure, 8 of the 13 blasted rats exhibited chronic tinnitus. While acoustic PPI remained intact and ABR thresholds recovered, the ABR wave P1-N1 amplitude reduction persisted in all blast-exposed rats. No differences in spatial cognition were observed, but blasted rats as a whole exhibited increased anxiety. MEMRI data revealed a bilateral increase in activity along the auditory pathway and in certain limbic regions of rats with tinnitus compared to age-matched controls. Taken together, our data suggest that while blast-induced tinnitus may play a role in auditory and limbic hyperactivity, the non-auditory effects of blast and potential traumatic brain injury may also exert an effect.

Peripheral auditory processing changes seasonally in Gambel’s white-crowned sparrow

PubMed Central

Caras, Melissa L.; Brenowitz, Eliot; Rubel, Edwin W

2010-01-01

Song in oscine birds is a learned behavior that plays important roles in breeding. Pronounced seasonal differences in song behavior, and in the morphology and physiology of the neural circuit underlying song production are well documented in many songbird species. Androgenic and estrogenic hormones largely mediate these seasonal changes. While much work has focused on the hormonal mechanisms underlying seasonal plasticity in songbird vocal production, relatively less work has investigated seasonal and hormonal effects on songbird auditory processing, particularly at a peripheral level. We addressed this issue in Gambel’s white-crowned sparrow (Zonotrichia leucophrys gambelii), a highly seasonal breeder. Photoperiod and hormone levels were manipulated in the laboratory to simulate natural breeding and non-breeding conditions. Peripheral auditory function was assessed by measuring the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs) of males and females in both conditions. Birds exposed to breeding-like conditions demonstrated elevated thresholds and prolonged peak latencies compared with birds housed under non-breeding-like conditions. There were no changes in DPOAEs, however, which indicates that the seasonal differences in ABRs do not arise from changes in hair cell function. These results suggest that seasons and hormones impact auditory processing as well as vocal production in wild songbirds. PMID:20563817

Hydrogen in drinking water attenuates noise-induced hearing loss in guinea pigs.

PubMed

Lin, Ying; Kashio, Akinori; Sakamoto, Takashi; Suzukawa, Keigo; Kakigi, Akinobu; Yamasoba, Tatsuya

2011-01-03

It has been shown that molecular hydrogen acts as a therapeutic and preventive antioxidant by selectively reducing the hydroxyl radical, the most cytotoxic of the reactive oxygen species. In the present study, we tested the hypothesis that acoustic damage in guinea pigs can be attenuated by the consumption of molecular hydrogen. Guinea pigs received normal water or hydrogen-rich water for 14 days before they were exposed to 115 dB SPL 4-kHz octave band noise for 3h. Animals in each group underwent measurements for auditory brainstem response (ABR) or distortion-product otoacoustic emissions (DPOAEs) before the treatment (baseline) and immediately, 1, 3, 7, and 14 days after noise exposure. The ABR thresholds at 2 and 4 kHz were significantly better on post-noise days 1, 3, and 14 in hydrogen-treated animals when compared to the normal water-treated controls. Compared to the controls, the hydrogen-treated animals showed greater amplitude of DPOAE input/output growth functions during the recovery process, with statistical significance detected on post-noise days 3 and 7. These findings suggest that hydrogen can facilitate the recovery of hair cell function and attenuate noise-induced temporary hearing loss. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

A study of hearing function and histopathologic changes in the cochlea of the type 2 diabetes model Tsumura Suzuki obese diabetes mouse.

PubMed

Tsuda, Junko; Sugahara, Kazuma; Hori, Takeshi; Kanagawa, Eiju; Takaki, Eiichi; Fujimoto, Mitsuaki; Nakai, Akira; Yamashita, Hiroshi

2016-11-01

This study used Tsumura Suzuki Obese Diabetes (TSOD) mice as a spontaneous type 2 diabetes model and Tsumura Suzuki Non-obesity (TSNO) mice as controls to investigate factors involved in the onset of hearing impairment. Body weight, blood glucose levels, and auditory brainstem responses (ABRs) were measured. The cochleae were excised and evaluated histopathologically. The TSOD mice showed significant hyperglycemia at 2-7 months and severe obesity at 5-10 months; significantly elevated ABR thresholds at 8-10 months; and the capillary lumens in the cochlea stria vascularis were narrower in the TSOD mice than in the TSNO mice. At 17 months, India ink vascular staining of the TSOD mice's cochleae revealed decreased capillary density in the stria vascularis. The vascular area of capillaries in the stria vascularis and the vascular area were significantly smaller in TSOD mice. Histopathological analysis showed vessel wall thickening in the modiolus and narrowed capillaries in the stria vascularis, suggesting reduced blood flow to the inner ear. The diabetes mice model used in our study showed early age-associated hearing loss, and histopathology showed findings of vessel wall thickening in the modiolus, narrowing of capillaries in the stria vascularis, and chronically reduced blood flow in the cochlea.

[Effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in the guinea pig].

PubMed

Feng, B; Jiang, S; Yang, W; Han, D; Zhang, S

2001-02-01

To define the effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in guinea pigs. The animals involved in the study were exposed to 8 Hz infrasound at 135dB SPL for 90 minutes in a reverberant chamber. The sinusoidal pendular test (SPT), auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) were respectively detected pre-exposure and at 0(within 2 hrs), 2 and 5 day after exposure. The ultrastructures of the inner ear were observed by scanning electron microscopy. The slow-phase velocity and the frequency of the vestibular nystagmus elicited by sinusoidal pendular test (SPT) declined slightly following infrasound exposure, but the changes were not significant (P > 0.05). No differences in the ABR thresholds, the latencies and the interval peak latencies of I, III, V waves were found between the normal and the experimental groups, and among experimental groups. The amplitudes of DPOAE at any frequency declined remarkably in all experimental groups. The ultrastructures of the inner ear were damaged to different extent. Infrasound could transiently depress the excitability of the vestibular end-organs, decrease the function of OHC in the organ of Corti and cause damage to the inner ear of guinea pigs.

Radioprotective Effect of Aminothiol PrC-210 on Irradiated Inner Ear of Guinea Pig

PubMed Central

Choo, Daniel I.; Riazuddin, Saima; Ahmed, Zubair M.

2015-01-01

Radiotherapy of individuals suffering with head & neck or brain tumors subserve the risk of sensorineural hearing loss. Here, we evaluated the protective effect of Aminothiol PrC-210 (3-(methyl-amino)-2-((methylamino)methyl)propane-1-thiol) on the irradiated inner ear of guinea pigs. An intra-peritoneal or intra-tympanic dose of PrC-210 was administered prior to receiving a dose of gamma radiation (3000 cGy) to each ear. Auditory Brainstem Responses (ABRs) were recorded one week and two weeks after the radiation and compared with the sham animal group. ABR thresholds of guinea pigs that received an intra-peritoneal dose of PrC-210 were significantly better compared to the non-treated, control animals at one week post-radiation. Morphologic analysis of the inner ear revealed significant inflammation and degeneration of the spiral ganglion in the irradiated animals not treated with PrC-210. In contrast, when treated with PrC-210 the radiation effect and injury to the spiral ganglion was significantly alleviated. PrC-210 had no apparent cytotoxic effect in vivo and did not affect the morphology or count of cochlear hair cells. These findings suggest that aminothiol PrC-210 attenuated radiation-induced cochlea damage for at least one week and protected hearing. PMID:26599238

Arctigenin protects against neuronal hearing loss by promoting neural stem cell survival and differentiation.

PubMed

Huang, Xinghua; Chen, Mo; Ding, Yan; Wang, Qin

2017-03-01

Neuronal hearing loss has become a prevalent health problem. This study focused on the function of arctigenin (ARC) in promoting survival and neuronal differentiation of mouse cochlear neural stem cells (NSCs), and its protection against gentamicin (GMC) induced neuronal hearing loss. Mouse cochlea was used to isolate NSCs, which were subsequently cultured in vitro. The effects of ARC on NSC survival, neurosphere formation, differentiation of NSCs, neurite outgrowth, and neural excitability in neuronal network in vitro were examined. Mechanotransduction ability demonstrated by intact cochlea, auditory brainstem response (ABR), and distortion product optoacoustic emissions (DPOAE) amplitude in mice were measured to evaluate effects of ARC on GMC-induced neuronal hearing loss. ARC increased survival, neurosphere formation, neuron differentiation of NSCs in mouse cochlear in vitro. ARC also promoted the outgrowth of neurites, as well as neural excitability of the NSC-differentiated neuron culture. Additionally, ARC rescued mechanotransduction capacity, restored the threshold shifts of ABR and DPOAE in our GMC ototoxicity murine model. This study supports the potential therapeutic role of ARC in promoting both NSCs proliferation and differentiation in vitro to functional neurons, thus supporting its protective function in the therapeutic treatment of neuropathic hearing loss in vivo. © 2017 Wiley Periodicals, Inc.

Detection Rates of Cortical Auditory Evoked Potentials at Different Sensation Levels in Infants with Sensory/Neural Hearing Loss and Auditory Neuropathy Spectrum Disorder

PubMed Central

Gardner-Berry, Kirsty; Chang, Hsiuwen; Ching, Teresa Y. C.; Hou, Sanna

2016-01-01

With the introduction of newborn hearing screening, infants are being diagnosed with hearing loss during the first few months of life. For infants with a sensory/neural hearing loss (SNHL), the audiogram can be estimated objectively using auditory brainstem response (ABR) testing and hearing aids prescribed accordingly. However, for infants with auditory neuropathy spectrum disorder (ANSD) due to the abnormal/absent ABR waveforms, alternative measures of auditory function are needed to assess the need for amplification and evaluate whether aided benefit has been achieved. Cortical auditory evoked potentials (CAEPs) are used to assess aided benefit in infants with hearing loss; however, there is insufficient information regarding the relationship between stimulus audibility and CAEP detection rates. It is also not clear whether CAEP detection rates differ between infants with SNHL and infants with ANSD. This study involved retrospective collection of CAEP, hearing threshold, and hearing aid gain data to investigate the relationship between stimulus audibility and CAEP detection rates. The results demonstrate that increases in stimulus audibility result in an increase in detection rate. For the same range of sensation levels, there was no difference in the detection rates between infants with SNHL and ANSD. PMID:27587922

Endoscopic Endonasal Transclival Approach to the Ventral Brainstem: Anatomic Study of the Safe Entry Zones Combining Fiber Dissection Technique with 7 Tesla Magnetic Resonance Guided Neuronavigation.

PubMed

Weiss, Alessandro; Perrini, Paolo; De Notaris, Matteo; Soria, Guadalupe; Carlos, Alarcon; Castagna, Maura; Lutzemberger, Lodovico; Santonocito, Orazio Santo; Catapano, Giuseppe; Kassam, Amin; Galino, Alberto Prats

2018-05-10

Treatment of intrinsic lesions of the ventral brainstem is a surgical challenge that requires complex skull base antero- and posterolateral approaches. More recently, endoscopic endonasal transclival approach (EETA) has been reported in the treatment of selected ventral brainstem lesions. In this study we explored the endoscopic ventral brainstem anatomy with the aim to describe the degree of exposure of the ventral safe entry zones. In addition, we used a newly developed method combining traditional white matter dissection with high-resolution 7T magnetic resonance imaging (MRI) of the same specimen coregistered using a neuronavigation system. Eight fresh-frozen latex-injected cadaver heads underwent EETA. Additional 8 formalin-fixed brainstems were dissected using Klingler technique guided by ultra-high resolution MRI. The EETA allows a wide exposure of different safe entry zones located on the ventral brainstem: the exposure of perioculomotor zone requires pituitary transposition and can be hindered by superior cerebellar artery. The peritrigeminal zone was barely visible and its exposure required an extradural anterior petrosectomy. The anterolateral sulcus of the medulla was visible in most of specimens, although its close relationship with the corticospinal tract makes it suboptimal as an entry point for intrinsic lesions. In all cases, the use of 7T-MRI allowed the identification of tiny fiber bundles, improving the quality of the dissection. Exposure of the ventral brainstem with EETA requires mastering surgical maneuvers, including pituitary transposition and extradural petrosectomy. The correlation of fiber dissection with 7T-MRI neuronavigation significantly improves the understanding of the brainstem anatomy.

Development of the Brainstem and Cerebellum in Autistic Patients.

ERIC Educational Resources Information Center

Hashimoto, Toshiaki; And Others

1995-01-01

This study of 102 individuals with autism found that the brainstem and cerebellum increased in size with age but were significantly smaller in autistic patients than in controls. Analysis of the speed of development suggests that brainstem and vermian abnormalities in autism were due to an early insult and hypoplasia rather than to progressive…