Solar recharging system for hearing aid cells.

PubMed

Gòmez Estancona, N; Tena, A G; Torca, J; Urruticoechea, L; Muñiz, L; Aristimuño, D; Unanue, J M; Torca, J; Urruticoechea, A

1994-09-01

We present a solar recharging system for nickel-cadmium cells of interest in areas where batteries for hearing aids are difficult to obtain. The charger has sun cells at the top. Luminous energy is converted into electrical energy, during the day and also at night if there is moonlight. The cost of the charger and hearing aid is very low at 35 US$. The use of solar recharging for hearing aids would be useful in alleviating the problems of deafness in parts of developing countries where there is no electricity.

Hearing Aids and Hearing Impaired Students in Rural Schools.

ERIC Educational Resources Information Center

Woodford, Charles

This paper describes functions of the components of hearing aids and provides a detailed procedure to detect hearing aid dysfunctions. The most common type of hearing aids for school children are the behind the ear type. Various hearing aid components change sound into an electrical signal, which is amplified and adjusted by a volume control. The…

Simultaneous masking between electric and acoustic stimulation in cochlear implant users with residual low-frequency hearing.

PubMed

Krüger, Benjamin; Büchner, Andreas; Nogueira, Waldo

2017-09-01

Ipsilateral electric-acoustic stimulation (EAS) is becoming increasingly important in cochlear implant (CI) treatment. Improvements in electrode designs and surgical techniques have contributed to improved hearing preservation during implantation. Consequently, CI implantation criteria have been expanded toward people with significant residual low-frequency hearing, who may benefit from the combined use of both the electric and acoustic stimulation in the same ear. However, only few studies have investigated the mutual interaction between electric and acoustic stimulation modalities. This work characterizes the interaction between both stimulation modalities using psychophysical masking experiments and cone beam computer tomography (CBCT). Two psychophysical experiments for electric and acoustic masking were performed to measure the hearing threshold elevation of a probe stimulus in the presence of a masker stimulus. For electric masking, the probe stimulus was an acoustic tone while the masker stimulus was an electric pulse train. For acoustic masking, the probe stimulus was an electric pulse train and the masker stimulus was an acoustic tone. Five EAS users, implanted with a CI and ipsilateral residual low-frequency hearing, participated in the study. Masking was determined at different electrodes and different acoustic frequencies. CBCT scans were used to determine the individual place-pitch frequencies of the intracochlear electrode contacts by using the Stakhovskaya place-to-frequency transformation. This allows the characterization of masking as a function of the difference between electric and acoustic stimulation sites, which we term the electric-acoustic frequency difference (EAFD). The results demonstrate a significant elevation of detection thresholds for both experiments. In electric masking, acoustic-tone thresholds increased exponentially with decreasing EAFD. In contrast, for the acoustic masking experiment, threshold elevations were present regardless of the tested EAFDs. Based on the present findings, we conclude that there is an asymmetry between the electric and the acoustic masker modalities. These observations have implications for the design and fitting of EAS sound-coding strategies. Copyright © 2017 Elsevier B.V. All rights reserved.

Spatial Release From Masking in Simulated Cochlear Implant Users With and Without Access to Low-Frequency Acoustic Hearing

PubMed Central

Dietz, Mathias; Hohmann, Volker; Jürgens, Tim

2015-01-01

For normal-hearing listeners, speech intelligibility improves if speech and noise are spatially separated. While this spatial release from masking has already been quantified in normal-hearing listeners in many studies, it is less clear how spatial release from masking changes in cochlear implant listeners with and without access to low-frequency acoustic hearing. Spatial release from masking depends on differences in access to speech cues due to hearing status and hearing device. To investigate the influence of these factors on speech intelligibility, the present study measured speech reception thresholds in spatially separated speech and noise for 10 different listener types. A vocoder was used to simulate cochlear implant processing and low-frequency filtering was used to simulate residual low-frequency hearing. These forms of processing were combined to simulate cochlear implant listening, listening based on low-frequency residual hearing, and combinations thereof. Simulated cochlear implant users with additional low-frequency acoustic hearing showed better speech intelligibility in noise than simulated cochlear implant users without acoustic hearing and had access to more spatial speech cues (e.g., higher binaural squelch). Cochlear implant listener types showed higher spatial release from masking with bilateral access to low-frequency acoustic hearing than without. A binaural speech intelligibility model with normal binaural processing showed overall good agreement with measured speech reception thresholds, spatial release from masking, and spatial speech cues. This indicates that differences in speech cues available to listener types are sufficient to explain the changes of spatial release from masking across these simulated listener types. PMID:26721918

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

PubMed

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

2017-05-01

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

Neural Processing of Musical and Vocal Emotions Through Cochlear Implants Simulation.

PubMed

Ahmed, Duha G; Paquette, Sebastian; Zeitouni, Anthony; Lehmann, Alexandre

2018-05-01

Cochlear implants (CIs) partially restore the sense of hearing in the deaf. However, the ability to recognize emotions in speech and music is reduced due to the implant's electrical signal limitations and the patient's altered neural pathways. Electrophysiological correlations of these limitations are not yet well established. Here we aimed to characterize the effect of CIs on auditory emotion processing and, for the first time, directly compare vocal and musical emotion processing through a CI-simulator. We recorded 16 normal hearing participants' electroencephalographic activity while listening to vocal and musical emotional bursts in their original form and in a degraded (CI-simulated) condition. We found prolonged P50 latency and reduced N100-P200 complex amplitude in the CI-simulated condition. This points to a limitation in encoding sound signals processed through CI simulation. When comparing the processing of vocal and musical bursts, we found a delay in latency with the musical bursts compared to the vocal bursts in both conditions (original and CI-simulated). This suggests that despite the cochlear implants' limitations, the auditory cortex can distinguish between vocal and musical stimuli. In addition, it adds to the literature supporting the complexity of musical emotion. Replicating this study with actual CI users might lead to characterizing emotional processing in CI users and could ultimately help develop optimal rehabilitation programs or device processing strategies to improve CI users' quality of life.

The distress of voice-hearing: the use of simulation for awareness, understanding and communication skill development in undergraduate nursing education.

PubMed

Orr, Fiona; Kellehear, Kevin; Armari, Elizabeth; Pearson, Arana; Holmes, Douglas

2013-11-01

Role-play scenarios are frequently used with undergraduate nursing students enrolled in mental health nursing subjects to simulate the experience of voice-hearing. However, role-play has limitations and typically does not involve those who hear voices. This collaborative project between mental health consumers who hear voices and nursing academics aimed to develop and assess simulated voice-hearing as an alternative learning tool that could provide a deeper understanding of the impact of voice-hearing, whilst enabling students to consider the communication skills required when interacting with voice-hearers. Simulated sounds and voices recorded by consumers on mp3 players were given to eighty final year nursing students undertaking a mental health elective. Students participated in various activities whilst listening to the simulations. Seventy-six (95%) students completed a written evaluation following the simulation, which assessed the benefits of the simulation and its implications for clinical practice. An analysis of the students' responses by an external evaluator indicated that there were three major learning outcomes: developing an understanding of voice-hearing, increasing students' awareness of its impact on functioning, and consideration of the communication skills necessary to engage with consumers who hear voices. Copyright © 2013 Elsevier Ltd. All rights reserved.

Do You Hear What I Hear? The Impact of a Hearing Voices Simulation on Affective Domain Attributes in Nursing Students.

PubMed

Ward, Terry D

2015-01-01

Affective domain teaching and learning can facilitate the reduction of stigmatization of clients with mental illness in nursing students. Experiential learning activities such as simulation are regarded as an effective method for facilitating student learning in the affective domain. The project reported here measured the impact of a simulation experience, "Hearing Voices Which Are Distressing," on attitudes, values, and beliefs of accelerated baccalaureate students caring for clients with mental illness who experienced hearing voices.

Potential Benefits of an Integrated Electric-Acoustic Sound Processor with Children: A Preliminary Report.

PubMed

Wolfe, Jace; Neumann, Sara; Schafer, Erin; Marsh, Megan; Wood, Mark; Baker, R Stanley

2017-02-01

A number of published studies have demonstrated the benefits of electric-acoustic stimulation (EAS) over conventional electric stimulation for adults with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. These benefits potentially include better speech recognition in quiet and in noise, better localization, improvements in sound quality, better music appreciation and aptitude, and better pitch recognition. There is, however, a paucity of published reports describing the potential benefits and limitations of EAS for children with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. The objective of this study was to explore the potential benefits of EAS for children. A repeated measures design was used to evaluate performance differences obtained with EAS stimulation versus acoustic- and electric-only stimulation. Seven users of Cochlear Nucleus Hybrid, Nucleus 24 Freedom, CI512, and CI422 implants were included in the study. Sentence recognition (assayed using the pediatric version of the AzBio sentence recognition test) was evaluated in quiet and at three fixed signal-to-noise ratios (SNR) (0, +5, and +10 dB). Functional hearing performance was also evaluated with the use of questionnaires, including the comparative version of the Speech, Spatial, and Qualities, the Listening Inventory for Education Revised, and the Children's Home Inventory for Listening Difficulties. Speech recognition in noise was typically better with EAS compared to participants' performance with acoustic- and electric-only stimulation, particularly when evaluated at the less favorable SNR. Additionally, in real-world situations, children generally preferred to use EAS compared to electric-only stimulation. Also, the participants' classroom teachers observed better hearing performance in the classroom with the use of EAS. Use of EAS provided better speech recognition in quiet and in noise when compared to performance obtained with use of acoustic- and electric-only stimulation, and children responded favorably to the use of EAS implemented in an integrated sound processor for real-world use. American Academy of Audiology

The effect of tinnitus specific intracochlear stimulation on speech perception in patients with unilateral or asymmetric hearing loss accompanied with tinnitus and the effect of formal auditory training.

PubMed

Arts, Remo A G J; George, Erwin L J; Janssen, Miranda A M L; Griessner, Andreas; Zierhofer, Clemens; Stokroos, Robert J

2018-06-01

Previous studies show that intracochlear electrical stimulation independent of environmental sounds appears to suppress tinnitus, even long-term. In order to assess the viability of this potential treatment option it is essential to study the effects of this tinnitus specific electrical stimulation on speech perception. A randomised, prospective crossover design. Ten patients with unilateral or asymmetric hearing loss and severe tinnitus complaints. The audiological effects of standard clinical CI, formal auditory training and tinnitus specific electrical stimulation were investigated. Results show that standard clinical CI in unilateral or asymmetric hearing loss is shown to be beneficial for speech perception in quiet, speech perception in noise and subjective hearing ability. Formal auditory training does not appear to improve speech perception performance. However, CI-related discomfort reduces significantly more rapidly during CI rehabilitation in subjects receiving formal auditory training. Furthermore, tinnitus specific electrical stimulation has neither positive nor negative effects on speech perception. In combination with the findings from previous studies on tinnitus suppression using intracochlear electrical stimulation independent of environmental sounds, the results of this study contribute to the viability of cochlear implantation based on tinnitus complaints.

Tolerable hearing aid delays. V. Estimation of limits for open canal fittings.

PubMed

Stone, Michael A; Moore, Brian C J; Meisenbacher, Katrin; Derleth, Ralph P

2008-08-01

Open canal fittings are a popular alternative to close-fitting earmolds for use with patients whose low-frequency hearing is near normal. Open canal fittings reduce the occlusion effect but also provide little attenuation of external air-borne sounds. The wearer therefore receives a mixture of air-borne sound and amplified but delayed sound through the hearing aid. To explore systematically the effect of the mixing, we simulated with varying degrees of complexity the effects of both a hearing loss and a high-quality hearing aid programmed to compensate for that loss, and used normal-hearing participants to assess the processing. The off-line processing was intended to simulate the percept of listening to the speech of a single (external) talker. The effect of introducing a delay on a subjective measure of speech quality (disturbance rating on a scale from 1 to 7, 7 being maximal disturbance) was assessed using both a constant gain and a gain that varied across frequency. In three experiments we assessed the effects of different amounts of delay, maximum aid gain and rate of change of gain with frequency. The simulated hearing aids were chosen to be appropriate for typical mild to moderate high-frequency losses starting at 1 or 2 kHz. Two of the experiments used simulations of linear hearing aids, whereas the third used fast-acting multichannel wide-dynamic-range compression and a simulation of loudness recruitment. In one experiment, a condition was included in which spectral ripples produced by comb-filtering were partially removed using a digital filter. For linear hearing aids, disturbance increased progressively with increasing delay and with decreasing rate of change of gain; the effect of amount of gain was small when the gain varied across frequency. The effect of reducing spectral ripples was also small. When the simulation of dynamic processes was included (experiment 3), the pattern with delay remained similar, but disturbance increased with increasing gain. It is argued that this is mainly due to disturbance increasing with increasing simulated hearing loss, probably because of the dynamic processing involved in the hearing aid and recruitment simulation. A disturbance rating of 3 may be considered as just acceptable. This rating was reached for delays of about 5 and 6 msec, for simulated hearing losses starting at 2 and 1 kHz, respectively. The perceptual effect of reducing the spectral ripples produced by comb-filtering was small; the effect was greatest when the hearing aid gain was small and when the hearing loss started at a low frequency.

Children Using Cochlear Implants Capitalize on Acoustical Hearing for Music Perception

PubMed Central

Hopyan, Talar; Peretz, Isabelle; Chan, Lisa P.; Papsin, Blake C.; Gordon, Karen A.

2012-01-01

Cochlear implants (CIs) electrically stimulate the auditory nerve providing children who are deaf with access to speech and music. Because of device limitations, it was hypothesized that children using CIs develop abnormal perception of musical cues. Perception of pitch and rhythm as well as memory for music was measured by the children’s version of the Montreal Battery of Evaluation of Amusia (MBEA) in 23 unilateral CI users and 22 age-matched children with normal hearing. Children with CIs were less accurate than their normal hearing peers (p < 0.05). CI users were best able to discern rhythm changes (p < 0.01) and to remember musical pieces (p < 0.01). Contrary to expectations, abilities to hear cues in music improved as the age at implantation increased (p < 0.01). Because the children implanted at older ages also had better low frequency hearing prior to cochlear implantation and were able to use this hearing by wearing hearing aids. Access to early acoustical hearing in the lower frequency ranges appears to establish a base for music perception, which can be accessed with later electrical CI hearing. PMID:23133430

Clinical, surgical, and electrical factors impacting residual hearing in cochlear implant surgery.

PubMed

Eshraghi, Adrien A; Ahmed, Jamal; Krysiak, Eric; Ila, Kadri; Ashman, Peter; Telischi, Fred F; Angeli, Simon; Prentiss, Sandra; Martinez, Diane; Valendia, Sandra

2017-04-01

This study recommends using soft surgical principal and round window insertion to protect residual hearing with favorable anatomical exposure. Further studies are needed to evaluate the impact of the electrical stimulation on the organ of corti and hearing. The objective of this study is to analyze various factors that impact on preservation of residual hearing post-implantation. A retrospective study was performed to analyze loss of residual hearing in a cohort of 225 patients implanted in a large academic center. Sixty-four patients met the inclusion criteria. The impact of age at implantation, gender, etiology of hearing loss, cochleostomy vs round window insertion, partial vs full insertion, and effect of initial stimulation were analyzed using appropriate statistical analysis. The overall hearing preservation rate for all implanted patients was 64%. Loss of residual hearing was significantly more observed in cases of cochleostomy and/or non-soft surgical techniques. No correlation was observed with age at implantation, gender, side of implant, device manufacturer, and presence of pre-lingual deafness vs post-lingual, full or partial electrode insertion. In addition, there was a small but significant decrease in hearing between pre-stimulation and post-stimulation audiograms at 6000 Hz.

Auditory Performance and Electrical Stimulation Measures in Cochlear Implant Recipients With Auditory Neuropathy Compared With Severe to Profound Sensorineural Hearing Loss.

PubMed

Attias, Joseph; Greenstein, Tally; Peled, Miriam; Ulanovski, David; Wohlgelernter, Jay; Raveh, Eyal

The aim of the study was to compare auditory and speech outcomes and electrical parameters on average 8 years after cochlear implantation between children with isolated auditory neuropathy (AN) and children with sensorineural hearing loss (SNHL). The study was conducted at a tertiary, university-affiliated pediatric medical center. The cohort included 16 patients with isolated AN with current age of 5 to 12.2 years who had been using a cochlear implant for at least 3.4 years and 16 control patients with SNHL matched for duration of deafness, age at implantation, type of implant, and unilateral/bilateral implant placement. All participants had had extensive auditory rehabilitation before and after implantation, including the use of conventional hearing aids. Most patients received Cochlear Nucleus devices, and the remainder either Med-El or Advanced Bionics devices. Unaided pure-tone audiograms were evaluated before and after implantation. Implantation outcomes were assessed by auditory and speech recognition tests in quiet and in noise. Data were also collected on the educational setting at 1 year after implantation and at school age. The electrical stimulation measures were evaluated only in the Cochlear Nucleus implant recipients in the two groups. Similar mapping and electrical measurement techniques were used in the two groups. Electrical thresholds, comfortable level, dynamic range, and objective neural response telemetry threshold were measured across the 22-electrode array in each patient. Main outcome measures were between-group differences in the following parameters: (1) Auditory and speech tests. (2) Residual hearing. (3) Electrical stimulation parameters. (4) Correlations of residual hearing at low frequencies with electrical thresholds at the basal, middle, and apical electrodes. The children with isolated AN performed equally well to the children with SNHL on auditory and speech recognition tests in both quiet and noise. More children in the AN group than the SNHL group were attending mainstream educational settings at school age, but the difference was not statistically significant. Significant between-group differences were noted in electrical measurements: the AN group was characterized by a lower current charge to reach subjective electrical thresholds, lower comfortable level and dynamic range, and lower telemetric neural response threshold. Based on pure-tone audiograms, the children with AN also had more residual hearing before and after implantation. Highly positive coefficients were found on correlation analysis between T levels across the basal and midcochlear electrodes and low-frequency acoustic thresholds. Prelingual children with isolated AN who fail to show expected oral and auditory progress after extensive rehabilitation with conventional hearing aids should be considered for cochlear implantation. Children with isolated AN had similar pattern as children with SNHL on auditory performance tests after cochlear implantation. The lower current charge required to evoke subjective and objective electrical thresholds in children with AN compared with children with SNHL may be attributed to the contribution to electrophonic hearing from the remaining neurons and hair cells. In addition, it is also possible that mechanical stimulation of the basilar membrane, as in acoustic stimulation, is added to the electrical stimulation of the cochlear implant.

[The experimental research of inner ear metabolism and electrical physiology of autoimmune sensorineural hearing loss].

PubMed

Tan, C; Cao, Y; Hu, P

1998-09-01

Inquire into the mechanism of inner ear pathological physiology in autoimmune sensorineural hearing loss (ASHL). With the auditory electric-physiological techniques and enzyme-histochemical method, the change of inner ear hearing function and enzyme activity were observed. These animals, which threshold of auditory nerve compound active potential (CAP) and cochlear microphonic potential(CM) heightening evidently, showed that the amplitude of endolymphatic potential(EP) (include-EP) bring down in various degrees, which was related to the change of the active of Na(+)-K(+)-ATPase and SDH in vascularis stria and endolymphatic sac. The abnormality of enzymes metabolism in inner ear tissues, which following autoimmune inflammation damage, is the pathological foundation of hearing dysfunction.

Alternative path to hearing: photonic sonogram hearing aid

NASA Astrophysics Data System (ADS)

Hara, Elmer H.

2002-05-01

For those with total hearing loss, there are no direct remedies except for electronic (i.e. cochlear) implants. They are invasive and do not always function in a satisfactory manner. Although sign language opens the window to a rich culture but communication with the hearing world is hindered. Lip reading can bridge that gap but communication is not without some stress. Inability to detect possible life threatening situations outside the visual field also affects the quality of life for those without the ability to hear. If the hearing process is viewed from the point of system engineering, there is a sound source and air is the transmission medium to the ear. The hearing structure of the ear converts mechanical vibrations to electrical signals that are then transmitted through nerve paths to the section of the brain where sound signals are processed. In most cases of total hearing loss, the hearing structure of the ear is non-functional. A cochlear implant bypasses this hearing structure. It electronically converts sounds from the air into their frequency components and feeds them into transmission nerve paths to the brain as electrical signals. This system-engineering point of view suggests that other pathways to the brain might be explored. The following section considers the visual pathway.

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

ERIC Educational Resources Information Center

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

2016-01-01

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

Restoration of hearing by hearing aids: conventional hearing aids – implantable hearing aids – cochlear implants – auditory brainstem implants

PubMed Central

Leuwer, R.; Müller, J.

2005-01-01

Aim of this report is to explain the current concept of hearing restoration using hearing aids. At present the main issues of conventional hearing aids are the relative benefits of analogue versus digital devices and different strategies for the improvement of hearing in noise. Implantable hearing aids provide a better sound quality and less distortion. The lack of directional microphones is the major disadvantage of the partially implantable hearing aids commercially available. Two different clinical studies about fully implantable hearing aids have been started in 2004. One of the most-promising developments seems to be the electric-acoustic stimulation. PMID:22073051

Evaluation of an Integrated Gas-Cooled Reactor Simulator and Brayton Turbine-Generator

NASA Technical Reports Server (NTRS)

Hissam, David Andy; Stewart, Eric T.

2006-01-01

A closed-loop brayton cycle, powered by a fission reactor, offers an attractive option for generating both planetary and in-space electric power. Non-nuclear testing of this type of system provides the opportunity to safely work out integration and system control challenges for a modest investment. Recognizing this potential, a team at Marshall Space Flight Center has evaluated the viability of integrating and testing an existing gas-cooled reactor simulator and a modified commercially available, off-the-shelf, brayton turbine-generator. Since these two systems were developed independently of one another, this evaluation had to determine if they could operate together at acceptable power levels, temperatures, and pressures. Thermal, fluid, and structural analyses show that this combined system can operate at acceptable power levels and temperatures. In addition, pressure drops across the reactor simulator, although higher than desired, are also viewed as acceptable. Three potential working fluids for the system were evaluated: N2, He/Ar, and He/Xe. Other potential issues, such as electrical breakdown in the generator and the operation of the brayton foil bearings using various gas mixtures, were also investigated.

Effects of age on F0 discrimination and intonation perception in simulated electric and electroacoustic hearing.

PubMed

Souza, Pamela; Arehart, Kathryn; Miller, Christi Wise; Muralimanohar, Ramesh Kumar

2011-02-01

Recent research suggests that older listeners may have difficulty processing information related to the fundamental frequency (F0) of voiced speech. In this study, the focus was on the mechanisms that may underlie this reduced ability. We examined whether increased age resulted in decreased ability to perceive F0 using fine-structure cues provided by the harmonic structure of voiced speech sounds or cues provided by high-rate envelope fluctuations (periodicity). Younger listeners with normal hearing and older listeners with normal to near-normal hearing completed two tasks of F0 perception. In the first task (steady state F0), the fundamental frequency difference limen (F0DL) was measured adaptively for synthetic vowel stimuli. In the second task (time-varying F0), listeners relied on variations in F0 to judge intonation of synthetic diphthongs. For both tasks, three processing conditions were created: eight-channel vocoding that preserved periodicity cues to F0; a simulated electroacoustic stimulation condition, which consisted of high-frequency vocoder processing combined with a low-pass-filtered portion, and offered both periodicity and fine-structure cues to F0; and an unprocessed condition. F0 difference limens for steady state vowel sounds and the ability to discern rising and falling intonations were significantly worse in the older subjects compared with the younger subjects. For both older and younger listeners, scores were lowest for the vocoded condition, and there was no difference in scores between the unprocessed and electroacoustic simulation conditions. Older listeners had difficulty using periodicity cues to obtain information related to talker fundamental frequency. However, performance was improved by combining periodicity cues with (low frequency) acoustic information, and that strategy should be considered in individuals who are appropriate candidates for such processing. For cochlear implant candidates, this effect might be achieved by partial electrode insertion providing acoustic stimulation in the low frequencies or by the combination of a traditional implant in one ear and a hearing aid in the opposite ear.

Contribution of a Contralateral Hearing Aid to Perception of Consonant Voicing, Intonation, and Emotional State in Adult Cochlear Implantees

ERIC Educational Resources Information Center

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

2012-01-01

Binaural hearing in cochlear implant (CI) users can be achieved either by bilateral implantation or bimodally with a contralateral hearing aid (HA). Binaural-bimodal hearing has the advantage of complementing the high-frequency electric information from the CI by low-frequency acoustic information from the HA. We examined the contribution of a…

Molecular biology of hearing

PubMed Central

Stöver, Timo; Diensthuber, Marc

2012-01-01

The inner ear is our most sensitive sensory organ and can be subdivided into three functional units: organ of Corti, stria vascularis and spiral ganglion. The appropriate stimulus for the organ of hearing is sound, which travels through the external auditory canal to the middle ear where it is transmitted to the inner ear. The inner ear houses the hair cells, the sensory cells of hearing. The inner hair cells are capable of mechanotransduction, the transformation of mechanical force into an electrical signal, which is the basic principle of hearing. The stria vascularis generates the endocochlear potential and maintains the ionic homeostasis of the endolymph. The dendrites of the spiral ganglion form synaptic contacts with the hair cells. The spiral ganglion is composed of neurons that transmit the electrical signals from the cochlea to the central nervous system. In recent years there has been significant progress in research on the molecular basis of hearing. An increasing number of genes and proteins related to hearing are being identified and characterized. The growing knowledge of these genes contributes not only to greater appreciation of the mechanism of hearing but also to a deeper understanding of the molecular basis of hereditary hearing loss. This basic research is a prerequisite for the development of molecular diagnostics and novel therapies for hearing loss. PMID:22558056

Interaural envelope correlation change discrimination in bilateral cochlear implantees: effects of mismatch, centering, and onset of deafness.

PubMed

Goupell, Matthew J

2015-03-01

Bilateral cochlear implant (CI) listeners can perform binaural tasks, but they are typically worse than normal-hearing (NH) listeners. To understand why this difference occurs and the mechanisms involved in processing dynamic binaural differences, interaural envelope correlation change discrimination sensitivity was measured in real and simulated CI users. In experiment 1, 11 CI (eight late deafened, three early deafened) and eight NH listeners were tested in an envelope correlation change discrimination task. Just noticeable differences (JNDs) were best for a matched place-of-stimulation and increased for an increasing mismatch. In experiment 2, attempts at intracranially centering stimuli did not produce lower JNDs. In experiment 3, the percentage of correct identifications of antiphasic carrier pulse trains modulated by correlated envelopes was measured as a function of mismatch and pulse rate. Sensitivity decreased for increasing mismatch and increasing pulse rate. The experiments led to two conclusions. First, envelope correlation change discrimination necessitates place-of-stimulation matched inputs. However, it is unclear if previous experience with acoustic hearing is necessary for envelope correlation change discrimination. Second, NH listeners presented with CI simulations demonstrated better performance than real CI listeners. If the simulations are realistic representations of electrical stimuli, real CI listeners appear to have difficulty processing interaural information in modulated signals.

Stability of Low-Frequency Residual Hearing in Patients Who Are Candidates for Combined Acoustic Plus Electric Hearing

ERIC Educational Resources Information Center

Yao, Wai Na; Turner, Christopher W.; Gantz, Bruce J.

2006-01-01

The purpose of this study was to investigate the stability over time of low-frequency auditory thresholds to better determine if the new technique of using a short-electrode cochlear implant that preserves residual low-frequency acoustic hearing can be a long-term solution for those with severe-to-profound hearing loss at high frequencies. The…

What's Hearing Loss?

MedlinePlus

... cells in the cochlea by turning sounds into electrical signals that stimulate the hearing nerve directly. Learning ... loss can read along to follow the action. Technology is changing all the time, and you will ...

Deafness Simulation: A Model for Enhancing Awareness and Sensitivity among Hearing Educators.

ERIC Educational Resources Information Center

Sevigny-Skyer, Solange C.; Dagel, Delbert D.

1990-01-01

The National Technical Institute for the Deaf developed and implemented a school-based deafness simulation project for hearing faculty members called "Keeping in Touch." Faculty members wore tinnitus maskers which produced a moderate-to-severe hearing loss and subsequently discussed their experiences, feelings, and communication…

Electromotile hearing: Acoustic tones mask psychophysical response to high-frequency electrical stimulation of intact guinea pig cochleaea)

PubMed Central

Le Prell, Colleen G.; Kawamoto, Kohei; Raphael, Yehoash; Dolan, David F.

2011-01-01

When sinusoidal electric stimulation is applied to the intact cochlea, a frequency-specific acoustic emission can be recorded in the ear canal. Acoustic emissions are produced by basilar membrane motion, and have been used to suggest a corresponding acoustic sensation termed “electromotile hearing.” Electromotile hearing has been specifically attributed to electric stimulation of outer hair cells in the intact organ of Corti. To determine the nature of the auditory perception produced by electric stimulation of a cochlea with intact outer hair cells, we tested guinea pigs in a psychophysical task. First, subjects were trained to report detection of sinusoidal acoustic stimuli and dynamic range was assessed using response latency. Subjects were then implanted with a ball electrode placed into scala tympani. Following the surgical implant procedure, subjects were transferred to a task in which acoustic signals were replaced by sinusoidal electric stimulation, and dynamic range was assessed again. Finally, the ability of acoustic pure-tone stimuli to mask the detection of the electric signals was assessed. Based on the masking effects, we conclude that sinusoidal electric stimulation of the intact cochlea results in perception of a tonal (rather than a broad-band or noisy) sound at a frequency of 8 kHz or above. PMID:17225416

The musician effect: does it persist under degraded pitch conditions of cochlear implant simulations?

PubMed Central

Fuller, Christina D.; Galvin, John J.; Maat, Bert; Free, Rolien H.; Başkent, Deniz

2014-01-01

Cochlear implants (CIs) are auditory prostheses that restore hearing via electrical stimulation of the auditory nerve. Compared to normal acoustic hearing, sounds transmitted through the CI are spectro-temporally degraded, causing difficulties in challenging listening tasks such as speech intelligibility in noise and perception of music. In normal hearing (NH), musicians have been shown to better perform than non-musicians in auditory processing and perception, especially for challenging listening tasks. This “musician effect” was attributed to better processing of pitch cues, as well as better overall auditory cognitive functioning in musicians. Does the musician effect persist when pitch cues are degraded, as it would be in signals transmitted through a CI? To answer this question, NH musicians and non-musicians were tested while listening to unprocessed signals or to signals processed by an acoustic CI simulation. The task increasingly depended on pitch perception: (1) speech intelligibility (words and sentences) in quiet or in noise, (2) vocal emotion identification, and (3) melodic contour identification (MCI). For speech perception, there was no musician effect with the unprocessed stimuli, and a small musician effect only for word identification in one noise condition, in the CI simulation. For emotion identification, there was a small musician effect for both. For MCI, there was a large musician effect for both. Overall, the effect was stronger as the importance of pitch in the listening task increased. This suggests that the musician effect may be more rooted in pitch perception, rather than in a global advantage in cognitive processing (in which musicians would have performed better in all tasks). The results further suggest that musical training before (and possibly after) implantation might offer some advantage in pitch processing that could partially benefit speech perception, and more strongly emotion and music perception. PMID:25071428

75 FR 74105 - Dominion Virginia Power and Old Dominion Electric Cooperative; Notice of Consideration of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-30

... Patel, Project Manager, US-APWR Projects Branch, Division of New Reactor Licensing, Office of New.... Before issuing the amendment, regardless of whether a hearing is requested, the Commission will make a... make it immediately effective, notwithstanding the request for a hearing. Any hearing held would take...

[Prevalence and characterization of hearing loss in workers exposed to industrial noise of the turbogenerated electric plant of a petrochemical industry].

PubMed

Montiel-López, María; Corzo-Alvarez, Gilbert; Chacín-Almarza, Betulio; Rojas-González, Liliana; Quevedo, Ana; Rendiles, Hernando

2006-06-01

The purpose of the present study was to assess the impact of occupational exposure to noise and its relationship with other factors that can induce hearing loss in the electric plant workers of a petrochemical industry of the west of Venezuela. A cross-sectional study was conducted that included sonometry tests, carried out according to the established methodology by COVENIN rules, and the occupational medical evaluation and liminal tonal audiometrics test in 75 workers. The equivalent noise levels (Leq) was quantified in different workplaces. It was found out that most of the workers are exposed to high noise levels [>85 dB(A)] and during more time than the recommended. All workers use hearing protectors appropriately. The hearing loss prevalence in workers was 16.0%, there were not noise-induced hearing losses. The hearing threshold registered in the audiometrics test was diminished, but inside the normal threshold values. We diagnosed 12 cases of conductive hearing loss, all grade I; there were not sensorial or mixed hearing losses. There was not a relationship between the equivalent noise level and hearing loss. It is suggested the design and implantation of a program of auditory conservation to protect the health and security of the workers and to conduct a longitudinal study considering the findings of the present study as it basis.

An examination of speech reception thresholds measured in a simulated reverberant cafeteria environment.

PubMed

Best, Virginia; Keidser, Gitte; Buchholz, Jörg M; Freeston, Katrina

2015-01-01

There is increasing demand in the hearing research community for the creation of laboratory environments that better simulate challenging real-world listening environments. The hope is that the use of such environments for testing will lead to more meaningful assessments of listening ability, and better predictions about the performance of hearing devices. Here we present one approach for simulating a complex acoustic environment in the laboratory, and investigate the effect of transplanting a speech test into such an environment. Speech reception thresholds were measured in a simulated reverberant cafeteria, and in a more typical anechoic laboratory environment containing background speech babble. The participants were 46 listeners varying in age and hearing levels, including 25 hearing-aid wearers who were tested with and without their hearing aids. Reliable SRTs were obtained in the complex environment, but led to different estimates of performance and hearing-aid benefit from those measured in the standard environment. The findings provide a starting point for future efforts to increase the real-world relevance of laboratory-based speech tests.

An examination of speech reception thresholds measured in a simulated reverberant cafeteria environment

PubMed Central

Best, Virginia; Keidser, Gitte; Buchholz, J(x004E7)rg M.; Freeston, Katrina

2016-01-01

Objective There is increasing demand in the hearing research community for the creation of laboratory environments that better simulate challenging real-world listening environments. The hope is that the use of such environments for testing will lead to more meaningful assessments of listening ability, and better predictions about the performance of hearing devices. Here we present one approach for simulating a complex acoustic environment in the laboratory, and investigate the effect of transplanting a speech test into such an environment. Design Speech reception thresholds were measured in a simulated reverberant cafeteria, and in a more typical anechoic laboratory environment containing background speech babble. Study Sample The participants were 46 listeners varying in age and hearing levels, including 25 hearing-aid wearers who were tested with and without their hearing aids. Results Reliable SRTs were obtained in the complex environment, but led to different estimates of performance and hearing aid benefit from those measured in the standard environment. Conclusions The findings provide a starting point for future efforts to increase the real-world relevance of laboratory-based speech tests. PMID:25853616

Long-Term, Non-Computer, Communication Simulations as Course Integration Activities

ERIC Educational Resources Information Center

Hamilton, James P.

2008-01-01

This article offers a few guidelines for constructing effective simulations. It presents a sample class activity called simulated public hearing which aims to integrate the various elements of a public speaking course into a more comprehensive whole. Properly designed, simulated hearings have elements of persuasive, informative, and impromptu…

47 CFR 20.19 - Hearing aid-compatible mobile handsets.

Code of Federal Regulations, 2010 CFR

2010-10-01

... and Hearing Aids,” ANSI C63.19-2006 (June 12, 2006), Institute of Electrical and Electronics Engineers... and Electronics Engineers, Inc., publisher. These incorporations by reference were approved by the...

Promoting Electric Vehicles Act of 2011

THOMAS, 112th Congress

Sen. Merkley, Jeff [D-OR

2011-05-11

Senate - 05/19/2011 Committee on Energy and Natural Resources. Hearings held. Hearings printed: S.Hrg. 112-38. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

[Which colours can we hear?: light stimulation of the hearing system].

PubMed

Wenzel, G I; Lenarz, T; Schick, B

2014-02-01

The success of conventional hearing aids and electrical auditory prostheses for hearing impaired patients is still limited in noisy environments and for sounds more complex than speech (e. g. music). This is partially due to the difficulty of frequency-specific activation of the auditory system using these devices. Stimulation of the auditory system using light pulses represents an alternative to mechanical and electrical stimulation. Light is a source of energy that can be very exactly focused and applied with little scattering, thus offering perspectives for optimal activation of the auditory system. Studies investigating light stimulation of sectors along the auditory pathway have shown stimulation of the auditory system is possible using light pulses. However, further studies and developments are needed before a new generation of light stimulation-based auditory prostheses can be made available for clinical application.

Bringing Hearing to the Deaf

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

Shipsey, Ian

In his talk, Shipsey will discuss the cochlear implant, the first device to successfully allow the profoundly deaf to regain some sense of hearing. A cochlear implant is a small electronic apparatus. Unlike a normal hearing aid, which amplifies sound, a cochlear implant is surgically implanted behind the ear where it converts sound waves into electrical impulses. These implants have instigated a popular but controversial revolution in the treatment of deafness, and they serve as a model for research in neuroscience and biomedical engineering. Shipsey will discuss the physiology of natural hearing from the perspective of a physicist. He willmore » also touch on the function of cochlear implants in the context of historical treatments, electrical engineering, psychophysics, clinical evaluation of efficacy and personal experience. Finally, Shipsey will address the social implications of cochlear implantation and the future outlook for auditory prostheses.« less

Spatial Release from Masking in Children: Effects of Simulated Unilateral Hearing Loss

PubMed Central

Corbin, Nicole E.; Buss, Emily; Leibold, Lori J.

2016-01-01

Objectives The purpose of this study was twofold: 1) to determine the effect of an acute simulated unilateral hearing loss on children’s spatial release from masking in two-talker speech and speech-shaped noise, and 2) to develop a procedure to be used in future studies that will assess spatial release from masking in children who have permanent unilateral hearing loss. There were three main predictions. First, spatial release from masking was expected to be larger in two-talker speech than speech-shaped noise. Second, simulated unilateral hearing loss was expected to worsen performance in all listening conditions, but particularly in the spatially separated two-talker speech masker. Third, spatial release from masking was expected to be smaller for children than for adults in the two-talker masker. Design Participants were 12 children (8.7 to 10.9 yrs) and 11 adults (18.5 to 30.4 yrs) with normal bilateral hearing. Thresholds for 50%-correct recognition of Bamford-Kowal-Bench sentences were measured adaptively in continuous two-talker speech or speech-shaped noise. Target sentences were always presented from a loudspeaker at 0° azimuth. The masker stimulus was either co-located with the target or spatially separated to +90° or −90° azimuth. Spatial release from masking was quantified as the difference between thresholds obtained when the target and masker were co-located and thresholds obtained when the masker was presented from +90° or − 90°. Testing was completed both with and without a moderate simulated unilateral hearing loss, created with a foam earplug and supra-aural earmuff. A repeated-measures design was used to compare performance between children and adults, and performance in the no-plug and simulated-unilateral-hearing-loss conditions. Results All listeners benefited from spatial separation of target and masker stimuli on the azimuth plane in the no-plug listening conditions; this benefit was larger in two-talker speech than in speech-shaped noise. In the simulated-unilateral-hearing-loss conditions, a positive spatial release from masking was observed only when the masker was presented ipsilateral to the simulated unilateral hearing loss. In the speech-shaped noise masker, spatial release from masking in the no-plug condition was similar to that obtained when the masker was presented ipsilateral to the simulated unilateral hearing loss. In contrast, in the two-talker speech masker, spatial release from masking in the no-plug condition was much larger than that obtained when the masker was presented ipsilateral to the simulated unilateral hearing loss. When either masker was presented contralateral to the simulated unilateral hearing loss, spatial release from masking was negative. This pattern of results was observed for both children and adults, although children performed more poorly overall. Conclusions Children and adults with normal bilateral hearing experience greater spatial release from masking for a two-talker speech than a speech-shaped noise masker. Testing in a two-talker speech masker revealed listening difficulties in the presence of disrupted binaural input that were not observed in a speech-shaped noise masker. This procedure offers promise for the assessment of spatial release from masking in children with permanent unilateral hearing loss. PMID:27787392

75 FR 54920 - In the Matter of Pacific Gas & Electric Company (Diablo Canyon Nuclear Power Plant, Units 1 and 2...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-09

...); Notice of Hearing (Application for License Renewal) September 1, 2010. Atomic Safety and Licensing Board... Regulatory Commission (NRC) published a notice of opportunity to request a hearing concerning the PG&E... for Peace (SLOMFP), a local public interest group, filed a request for hearing and asserted five...

Temporal masking functions for listeners with real and simulated hearing loss

PubMed Central

Desloge, Joseph G.; Reed, Charlotte M.; Braida, Louis D.; Perez, Zachary D.; Delhorne, Lorraine A.

2011-01-01

A functional simulation of hearing loss was evaluated in its ability to reproduce the temporal masking functions for eight listeners with mild to severe sensorineural hearing loss. Each audiometric loss was simulated in a group of age-matched normal-hearing listeners through a combination of spectrally-shaped masking noise and multi-band expansion. Temporal-masking functions were obtained in both groups of listeners using a forward-masking paradigm in which the level of a 110-ms masker required to just mask a 10-ms fixed-level probe (5-10 dB SL) was measured as a function of the time delay between the masker offset and probe onset. At each of four probe frequencies (500, 1000, 2000, and 4000 Hz), temporal-masking functions were obtained using maskers that were 0.55, 1.0, and 1.15 times the probe frequency. The slopes and y-intercepts of the masking functions were not significantly different for listeners with real and simulated hearing loss. The y-intercepts were positively correlated with level of hearing loss while the slopes were negatively correlated. The ratio of the slopes obtained with the low-frequency maskers relative to the on-frequency maskers was similar for both groups of listeners and indicated a smaller compressive effect than that observed in normal-hearing listeners. PMID:21877806

Cognitive hearing aids? Insights and possibilities

NASA Astrophysics Data System (ADS)

Petersen, Eline Borch; Lunner, Thomas

2015-12-01

The working memory plays an important role in successfully overcoming adverse listening conditions and should consequently be considered when designing and testing hearing aids. A number of studies have established the relationship between hearing in noise and working memory involvement, but with the Sentence-final Word Identification and Recall (SWIRL) test, it is possible to show that working memory is also involved in listening under favorable conditions and that noise reduction has a positive influence in situation with very little noise. Although the capacity of the working memory is a finite individual size, its involvement can differ with fatigue and other factors and individualization of hearing aids should take this into account to obtain the best performance. A way of individually adapting hearing aids is based on changes in the electrical activity of the brain (EEG). Here we present the possibilities that arise from using EEG and show that ear-mounted electrodes is able to record useful EEG that can be explored for individualization of hearing aids. Such an adaptation could be done based on changes in the electrical activity of the brain (EEG). Here we present the possibilities that arise from using EEG and show that ear-mounted electrodes is able to record useful EEG that can be explored for individualization of hearing aids.

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

PubMed

Ni, D

1992-12-01

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

Understanding Public Policy Making through the Work of Committees: Utilizing a Student-Led Congressional Hearing Simulation

ERIC Educational Resources Information Center

Rinfret, Sara R.; Pautz, Michelle C.

2015-01-01

In an effort to help students better understand the complexity of making environmental policy and the role of policy actors in this process, we developed a mock congressional hearing simulation. In this congressional hearing, students in two environmental policy courses take on the roles of members of Congress and various interest groups to…

Effects of age on F0-discrimination and intonation perception in simulated electric and electro-acoustic hearing

PubMed Central

Souza, Pamela; Arehart, Kathryn; Miller, Christi Wise; Muralimanohar, Ramesh Kumar

2010-01-01

Objectives Recent research suggests that older listeners may have difficulty processing information related to the fundamental frequency (F0) of voiced speech. In this study, the focus was on the mechanisms that may underlie this reduced ability. We examined whether increased age resulted in decreased ability to perceive F0 using fine structure cues provided by the harmonic structure of voiced speech sounds and/or cues provided by high-rate envelope fluctuations (periodicity). Design Younger listeners with normal hearing and older listeners with normal to near-normal hearing completed two tasks of F0 perception. In the first task (steady-state F0), the fundamental frequency difference limen (F0DL) was measured adaptively for synthetic vowel stimuli. In the second task (time-varying F0), listeners relied on variations in F0 to judge intonation of synthetic diphthongs. For both tasks, three processing conditions were created: 8-channel vocoding which preserved periodicity cues to F0; a simulated electroacoustic stimulation condition, which consisted of high-frequency vocoder processing combined with a low-pass filtered portion, and offered both periodicity and fine-structure cues to F0; and an unprocessed condition. Results F0 difference limens for steady-state vowel sounds and the ability to discern rising and falling intonations were significantly worse in the older subjects compared to the younger subjects. For both older and younger listeners scores were lowest for the vocoded condition, and there was no difference in scores between the unprocessed and electroacoustic simulation conditions. Conclusions Older listeners had difficulty using periodicity cues to obtain information related to talker fundamental frequency. However, performance was improved by combining periodicity cues with (low-frequency) acoustic information, and that strategy should be considered in individuals who are appropriate candidates for such processing. For cochlear implant candidates, that effect might be achieved by partial electrode insertion providing acoustic stimulation in the low frequencies; or by the combination of a traditional implant in one ear and a hearing aid in the opposite ear. PMID:20739892

Does the accuracy of blood pressure measurement correlate with hearing loss of the observer?

PubMed

Song, Soohwa; Lee, Jongshill; Chee, Youngjoon; Jang, Dong Pyo; Kim, In Young

2014-02-01

The auscultatory method is influenced by the hearing level of the observers. If the observer has hearing loss, it is possible to measure blood pressure inaccurately by misreading the Korotkoff sounds at systolic blood pressure (SBP) and diastolic blood pressure (DBP). Because of the potential clinical problems this discrepancy may cause, we used a hearing loss simulator to determine how hearing level affects the accuracy of blood pressure measurements. Two data sets (data set A, 32 Korotkoff sound video clips recorded by the British Hypertension Society; data set B, 28 Korotkoff sound data acquired from the Korotkoff sound recording system developed by Hanyang University) were used and all the data were attenuated to simulate a hearing loss of 5, 10, 15, 20, and 25 dB using the hearing loss simulator. Five observers with normal hearing assessed the blood pressures from these data sets and the differences between the values measured from the original recordings (no attenuation) and the attenuated versions were analyzed. Greater attenuation of the Korotkoff sounds, or greater hearing loss, resulted in larger blood pressure measurement differences when compared with the original data. When measuring blood pressure with hearing loss, the SBP tended to be underestimated and the DBP was overestimated. The mean differences between the original data and the 25 dB hearing loss data for the two data sets combined were 1.55±2.71 and -4.32±4.21 mmHg for SBP and DBP, respectively. This experiment showed that the accuracy of blood pressure measurements using the auscultatory method is affected by observer hearing level. Therefore, to reduce possible error using the auscultatory method, observers' hearing should be tested.

Masking Release in Children and Adults With Hearing Loss When Using Amplification

PubMed Central

McCreery, Ryan; Kopun, Judy; Lewis, Dawna; Alexander, Joshua; Stelmachowicz, Patricia

2016-01-01

Purpose This study compared masking release for adults and children with normal hearing and hearing loss. For the participants with hearing loss, masking release using simulated hearing aid amplification with 2 different compression speeds (slow, fast) was compared. Method Sentence recognition in unmodulated noise was compared with recognition in modulated noise (masking release). Recognition was measured for participants with hearing loss using individualized amplification via the hearing-aid simulator. Results Adults with hearing loss showed greater masking release than the children with hearing loss. Average masking release was small (1 dB) and did not depend on hearing status. Masking release was comparable for slow and fast compression. Conclusions The use of amplification in this study contrasts with previous studies that did not use amplification. The results suggest that when differences in audibility are reduced, participants with hearing loss may be able to take advantage of dips in the noise levels, similar to participants with normal hearing. Although children required a more favorable signal-to-noise ratio than adults for both unmodulated and modulated noise, masking release was not statistically different. However, the ability to detect a difference may have been limited by the small amount of masking release observed. PMID:26540194

21 CFR 874.3330 - Master hearing aid.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Master hearing aid. 874.3330 Section 874.3330 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3330 Master hearing aid. (a) Identification. A master hearing aid is an electronic device intended to simulate a hearing aid during audiometric...

21 CFR 874.3330 - Master hearing aid.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Master hearing aid. 874.3330 Section 874.3330 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3330 Master hearing aid. (a) Identification. A master hearing aid is an electronic device intended to simulate a hearing aid during audiometric...

21 CFR 874.3330 - Master hearing aid.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Master hearing aid. 874.3330 Section 874.3330 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3330 Master hearing aid. (a) Identification. A master hearing aid is an electronic device intended to simulate a hearing aid during audiometric...

21 CFR 874.3330 - Master hearing aid.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Master hearing aid. 874.3330 Section 874.3330 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3330 Master hearing aid. (a) Identification. A master hearing aid is an electronic device intended to simulate a hearing aid during audiometric...

21 CFR 874.3330 - Master hearing aid.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Master hearing aid. 874.3330 Section 874.3330 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3330 Master hearing aid. (a) Identification. A master hearing aid is an electronic device intended to simulate a hearing aid during audiometric...

Masking Release in Children and Adults with Hearing Loss When Using Amplification

ERIC Educational Resources Information Center

Brennan, Marc; McCreery, Ryan; Kopun, Judy; Lewis, Dawna; Alexander, Joshua; Stelmachowicz, Patricia

2016-01-01

Purpose: This study compared masking release for adults and children with normal hearing and hearing loss. For the participants with hearing loss, masking release using simulated hearing aid amplification with 2 different compression speeds (slow, fast) was compared. Method: Sentence recognition in unmodulated noise was compared with recognition…

Vowel perception by noise masked normal-hearing young adults

NASA Astrophysics Data System (ADS)

Richie, Carolyn; Kewley-Port, Diane; Coughlin, Maureen

2005-08-01

This study examined vowel perception by young normal-hearing (YNH) adults, in various listening conditions designed to simulate mild-to-moderate sloping sensorineural hearing loss. YNH listeners were individually age- and gender-matched to young hearing-impaired (YHI) listeners tested in a previous study [Richie et al., J. Acoust. Soc. Am. 114, 2923-2933 (2003)]. YNH listeners were tested in three conditions designed to create equal audibility with the YHI listeners; a low signal level with and without a simulated hearing loss, and a high signal level with a simulated hearing loss. Listeners discriminated changes in synthetic vowel tokens /smcapi e ɛ invv æ/ when F1 or F2 varied in frequency. Comparison of YNH with YHI results failed to reveal significant differences between groups in terms of performance on vowel discrimination, in conditions of similar audibility by using both noise masking to elevate the hearing thresholds of the YNH and applying frequency-specific gain to the YHI listeners. Further, analysis of learning curves suggests that while the YHI listeners completed an average of 46% more test blocks than YNH listeners, the YHI achieved a level of discrimination similar to that of the YNH within the same number of blocks. Apparently, when age and gender are closely matched between young hearing-impaired and normal-hearing adults, performance on vowel tasks may be explained by audibility alone.

Hearing aid malfunction detection system

NASA Technical Reports Server (NTRS)

Kessinger, R. L. (Inventor)

1977-01-01

A malfunction detection system for detecting malfunctions in electrical signal processing circuits is disclosed. Malfunctions of a hearing aid in the form of frequency distortion and/or inadequate amplification by the hearing aid amplifier, as well as weakening of the hearing aid power supply are detectable. A test signal is generated and a timed switching circuit periodically applies the test signal to the input of the hearing aid amplifier in place of the input signal from the microphone. The resulting amplifier output is compared with the input test signal used as a reference signal. The hearing aid battery voltage is also periodically compared to a reference voltage. Deviations from the references beyond preset limits cause a warning system to operate.

A narrative study of the experiences of student nurses who have participated in the Hearing Voices that are Distressing simulation.

PubMed

Hamilton Wilson, Jane E; Azzopardi, Wendy; Sager, Shelley; Gould, Brian; Conroy, Sherrill; Deegan, Patricia; Archie, Suzanne

2009-01-01

The aim of this study was to provide nursing students with an experiential learning opportunity which simulated living with the challenge of voice hearing. The purpose was to access understanding and insights of nursing students who completed "Hearing Voices that are Distressing: A Training Experience and Simulation for Students" (Deegan, 1996). Using a narrative research design and a convenience sample of 27 nursing students, participants were asked to respond in written format to three open ended prompts immediately following their participation in the simulation. Data generated was subjected to a thematic content analysis using a manual cut and paste approach to inductively find meanings and insights elicited from the respondents' actual words. Affirmed in this study was the use of this teaching tool to assist the students in their understanding of the challenges posed by voice hearing.

Electronic filters, hearing aids and methods

NASA Technical Reports Server (NTRS)

Engebretson, A. Maynard (Inventor)

1995-01-01

An electronic filter for an electroacoustic system. The system has a microphone for generating an electrical output from external sounds and an electrically driven transducer for emitting sound. Some of the sound emitted by the transducer returns to the microphone means to add a feedback contribution to its electrical output. The electronic filter includes a first circuit for electronic processing of the electrical output of the microphone to produce a first signal. An adaptive filter, interconnected with the first circuit, performs electronic processing of the first signal to produce an adaptive output to the first circuit to substantially offset the feedback contribution in the electrical output of the microphone, and the adaptive filter includes means for adapting only in response to polarities of signals supplied to and from the first circuit. Other electronic filters for hearing aids, public address systems and other electroacoustic systems, as well as such systems and methods of operating them are also disclosed.

The Benefits of Residual Hair Cell Function for Speech and Music Perception in Pediatric Bimodal Cochlear Implant Listeners.

PubMed

Cheng, Xiaoting; Liu, Yangwenyi; Wang, Bing; Yuan, Yasheng; Galvin, John J; Fu, Qian-Jie; Shu, Yilai; Chen, Bing

2018-01-01

The aim of this study was to investigate the benefits of residual hair cell function for speech and music perception in bimodal pediatric Mandarin-speaking cochlear implant (CI) listeners. Speech and music performance was measured in 35 Mandarin-speaking pediatric CI users for unilateral (CI-only) and bimodal listening. Mandarin speech perception was measured for vowels, consonants, lexical tones, and sentences in quiet. Music perception was measured for melodic contour identification (MCI). Combined electric and acoustic hearing significantly improved MCI and Mandarin tone recognition performance, relative to CI-only performance. For MCI, performance was significantly better with bimodal listening for all semitone spacing conditions ( p < 0.05 in all cases). For tone recognition, bimodal performance was significantly better only for tone 2 (rising; p < 0.05). There were no significant differences between CI-only and CI + HA for vowel, consonant, or sentence recognition. The results suggest that combined electric and acoustic hearing can significantly improve perception of music and Mandarin tones in pediatric Mandarin-speaking CI patients. Music and lexical tone perception depends strongly on pitch perception, and the contralateral acoustic hearing coming from residual hair cell function provided pitch cues that are generally not well preserved in electric hearing.

Paired comparisons of nonlinear frequency compression, extended bandwidth, and restricted bandwidth hearing-aid processing for children and adults with hearing loss

PubMed Central

Brennan, Marc A.; McCreery, Ryan; Kopun, Judy; Hoover, Brenda; Alexander, Joshua; Lewis, Dawna; Stelmachowicz, Patricia G.

2014-01-01

Background Preference for speech and music processed with nonlinear frequency compression and two controls (restricted and extended bandwidth hearing-aid processing) was examined in adults and children with hearing loss. Purpose Determine if stimulus type (music, sentences), age (children, adults) and degree of hearing loss influence listener preference for nonlinear frequency compression, restricted bandwidth and extended bandwidth. Research Design Within-subject, quasi-experimental study. Using a round-robin procedure, participants listened to amplified stimuli that were 1) frequency-lowered using nonlinear frequency compression, 2) low-pass filtered at 5 kHz to simulate the restricted bandwidth of conventional hearing aid processing, or 3) low-pass filtered at 11 kHz to simulate extended bandwidth amplification. The examiner and participants were blinded to the type of processing. Using a two-alternative forced-choice task, participants selected the preferred music or sentence passage. Study Sample Sixteen children (8–16 years) and 16 adults (19–65 years) with mild-to-severe sensorineural hearing loss. Intervention All subjects listened to speech and music processed using a hearing-aid simulator fit to the Desired Sensation Level algorithm v.5.0a (Scollie et al, 2005). Results Children and adults did not differ in their preferences. For speech, participants preferred extended bandwidth to both nonlinear frequency compression and restricted bandwidth. Participants also preferred nonlinear frequency compression to restricted bandwidth. Preference was not related to degree of hearing loss. For music, listeners did not show a preference. However, participants with greater hearing loss preferred nonlinear frequency compression to restricted bandwidth more than participants with less hearing loss. Conversely, participants with greater hearing loss were less likely to prefer extended bandwidth to restricted bandwidth. Conclusion Both age groups preferred access to high frequency sounds, as demonstrated by their preference for either the extended bandwidth or nonlinear frequency compression conditions over the restricted bandwidth condition. Preference for extended bandwidth can be limited for those with greater degrees of hearing loss, but participants with greater hearing loss may be more likely to prefer nonlinear frequency compression. Further investigation using participants with more severe hearing loss may be warranted. PMID:25514451

The CAPOS mutation in ATP1A3 alters Na/K-ATPase function and results in auditory neuropathy which has implications for management.

PubMed

Tranebjærg, Lisbeth; Strenzke, Nicola; Lindholm, Sture; Rendtorff, Nanna D; Poulsen, Hanne; Khandelia, Himanshu; Kopec, Wojciech; Lyngbye, Troels J Brünnich; Hamel, Christian; Delettre, Cecile; Bocquet, Beatrice; Bille, Michael; Owen, Hanne H; Bek, Toke; Jensen, Hanne; Østergaard, Karen; Möller, Claes; Luxon, Linda; Carr, Lucinda; Wilson, Louise; Rajput, Kaukab; Sirimanna, Tony; Harrop-Griffiths, Katherine; Rahman, Shamima; Vona, Barbara; Doll, Julia; Haaf, Thomas; Bartsch, Oliver; Rosewich, Hendrik; Moser, Tobias; Bitner-Glindzicz, Maria

2018-02-01

Cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorineural hearing impairment (CAPOS) is a rare clinically distinct syndrome caused by a single dominant missense mutation, c.2452G>A, p.Glu818Lys, in ATP1A3, encoding the neuron-specific alpha subunit of the Na+/K+-ATPase α3. Allelic mutations cause the neurological diseases rapid dystonia Parkinsonism and alternating hemiplegia of childhood, disorders which do not encompass hearing or visual impairment. We present detailed clinical phenotypic information in 18 genetically confirmed patients from 11 families (10 previously unreported) from Denmark, Sweden, UK and Germany indicating a specific type of hearing impairment-auditory neuropathy (AN). All patients were clinically suspected of CAPOS and had hearing problems. In this retrospective analysis of audiological data, we show for the first time that cochlear outer hair cell activity was preserved as shown by the presence of otoacoustic emissions and cochlear microphonic potentials, but the auditory brainstem responses were grossly abnormal, likely reflecting neural dyssynchrony. Poor speech perception was observed, especially in noise, which was beyond the hearing level obtained in the pure tone audiograms in several of the patients presented here. Molecular modelling and in vitro electrophysiological studies of the specific CAPOS mutation were performed. Heterologous expression studies of α3 with the p.Glu818Lys mutation affects sodium binding to, and release from, the sodium-specific site in the pump, the third ion-binding site. Molecular dynamics simulations confirm that the structure of the C-terminal region is affected. In conclusion, we demonstrate for the first time evidence for auditory neuropathy in CAPOS syndrome, which may reflect impaired propagation of electrical impulses along the spiral ganglion neurons. This has implications for diagnosis and patient management. Auditory neuropathy is difficult to treat with conventional hearing aids, but preliminary improvement in speech perception in some patients suggests that cochlear implantation may be effective in CAPOS patients.

75 FR 59673 - Public Hearing Locations for the Proposed Fuel Economy Labels

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-28

... types, including electric vehicles (EV), plug-in hybrid electric vehicles (PHEV), and conventional... purchase decisions and to address the entrance of advanced technology vehicles into the U.S. market. The...

The role of first formant information in simulated electro-acoustic hearing.

PubMed

Verschuur, Carl; Boland, Conor; Frost, Emily; Constable, Jack

2013-06-01

Cochlear implant (CI) recipients with residual hearing show improved performance with the addition of low-frequency acoustic stimulation (electro-acoustic stimulation, EAS). The present study sought to determine whether a synthesized first formant (F1) signal provided benefit to speech recognition in simulated EAS hearing and to compare such benefit with that from other low-frequency signals. A further aim was to determine if F1 amplitude or frequency was more important in determining benefit and if F1 benefit varied with formant bandwidth. In two experiments, sentence recordings from a male speaker were processed via a simulation of a partial insertion CI, and presented to normal hearing listeners in combination with various low-frequency signals, including a tone tracking fundamental frequency (F0), low-pass filtered speech, and signals based on F1 estimation. A simulated EAS benefit was found with F1 signals, and was similar to the benefit from F0 or low-pass filtered speech. The benefit did not differ significantly with the narrowing or widening of the F1 bandwidth. The benefit from low-frequency envelope signals was significantly less than the benefit from any low-frequency signal containing fine frequency information. Results indicate that F1 provides a benefit in simulated EAS hearing but low frequency envelope information is less important than low frequency fine structure in determining such benefit.

Temporal Intraspeech Masking of Plosive Bursts: Effects of Hearing Loss and Frequency Shaping

ERIC Educational Resources Information Center

Mackersie, Carol L.

2007-01-01

Purpose: The purposes were (a) to compare masking of consonant bursts by adjacent vowels for listeners with and without hearing loss and (b) to determine the extent to which the temporal intraspeech masking can be reduced by a simulated hearing-aid frequency-response shaping. Method: Fourteen adults with sensorineural hearing loss and 10 with…

Public Notice: Electric Boat Corporation, CWA-01-2018-0002

EPA Pesticide Factsheets

Notice of Proposed Assessment of Class II Civil Penalty and Notice of Opportunity for a Hearing under Sections 309(g) of the Clean Water Act (CWA) for Electric Boat Corporation, Groton, CT, CWA-01-2018-0002

Electronic filters, hearing aids and methods

NASA Technical Reports Server (NTRS)

Engebretson, A. Maynard (Inventor); O'Connell, Michael P. (Inventor); Zheng, Baohua (Inventor)

1991-01-01

An electronic filter for an electroacoustic system. The system has a microphone for generating an electrical output from external sounds and an electrically driven transducer for emitting sound. Some of the sound emitted by the transducer returns to the microphone means to add a feedback contribution to its electical output. The electronic filter includes a first circuit for electronic processing of the electrical output of the microphone to produce a filtered signal. An adaptive filter, interconnected with the first circuit, performs electronic processing of the filtered signal to produce an adaptive output to the first circuit to substantially offset the feedback contribution in the electrical output of the microphone, and the adaptive filter includes means for adapting only in response to polarities of signals supplied to and from the first circuit. Other electronic filters for hearing aids, public address systems and other electroacoustic systems, as well as such systems, and methods of operating them are also disclosed.

Electronic filters, signal conversion apparatus, hearing aids and methods

NASA Technical Reports Server (NTRS)

Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

1994-01-01

An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed.

Electrically evoked reticular lamina and basilar membrane vibrations in mice with alpha tectorin C1509G mutation

NASA Astrophysics Data System (ADS)

Ren, Tianying; He, Wenxuan

2015-12-01

Mechanical coupling between the tectorial membrane and the hair bundles of outer hair cells is crucial for stimulating mechanoelectrical transduction channels, which convert sound-induced vibrations into electrical signal, and for transmitting outer hair cell-generated force back to the basilar membrane to boost hearing sensitivity. It has been demonstrated that the detached tectorial membrane in mice with C1509G alpha tectorin mutation caused hearing loss, but enhanced electrically evoked otoacoustic emissions. To understand how the mutated cochlea emits sounds, the reticular lamina and basilar membrane vibrations were measured in the electrically stimulated cochlea in this study. The results showed that the electrically evoked basilar membrane vibration decreased dramatically while the reticular lamina vibration and otoacoustic emissions exhibited no significant change in C1509G mutation mice. This result indicates that a functional cochlear amplifier and a normal basilar membrane vibration are not required for the outer hair cell-generated sound to exit the cochlea.

[Technical advancements in cochlear implants : State of the art].

PubMed

Büchner, A; Gärtner, L

2017-04-01

Twenty years ago, cochlear implants (CI) were indicated only in cases of profound hearing loss or complete deafness. While from today's perspective the technology was clumsy and provided patients with only limited speech comprehension in quiet scenarios, successive advances in CI technology and the consequent substantial hearing improvements over time have since then resulted in continuous relaxation of indication criteria toward residual hearing. While achievements in implant and processor electronics have been one key factor for the ever-improving hearing performance, development of electro-acoustic CI systems-together with atraumatic implantation concepts-has led to enormous improvements in patients with low-frequency residual hearing. Manufactures have designed special processors with integrated hearing aid components for this patient group, which are capable of conveying acoustic and electric stimulation. A further milestone in improvement of hearing in challenging listening environments was the adoption of signal enhancement algorithms and assistive listening devices from the hearing aid industry. This article gives an overview of the current state of the art in the abovementioned areas of CI technology.

A bill to amend the Energy Policy and Conservation Act to establish efficiency standards for bottle-type water dispensers, commercial hot food holding cabinets, and portable electric spas.

THOMAS, 111th Congress

Sen. Menendez, Robert [D-NJ

2010-03-01

Senate - 03/10/2010 Committee on Energy and Natural Resources. Hearings held. Hearings printed: S.Hrg. 111-402. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Automatic Speech Recognition Predicts Speech Intelligibility and Comprehension for Listeners With Simulated Age-Related Hearing Loss.

PubMed

Fontan, Lionel; Ferrané, Isabelle; Farinas, Jérôme; Pinquier, Julien; Tardieu, Julien; Magnen, Cynthia; Gaillard, Pascal; Aumont, Xavier; Füllgrabe, Christian

2017-09-18

The purpose of this article is to assess speech processing for listeners with simulated age-related hearing loss (ARHL) and to investigate whether the observed performance can be replicated using an automatic speech recognition (ASR) system. The long-term goal of this research is to develop a system that will assist audiologists/hearing-aid dispensers in the fine-tuning of hearing aids. Sixty young participants with normal hearing listened to speech materials mimicking the perceptual consequences of ARHL at different levels of severity. Two intelligibility tests (repetition of words and sentences) and 1 comprehension test (responding to oral commands by moving virtual objects) were administered. Several language models were developed and used by the ASR system in order to fit human performances. Strong significant positive correlations were observed between human and ASR scores, with coefficients up to .99. However, the spectral smearing used to simulate losses in frequency selectivity caused larger declines in ASR performance than in human performance. Both intelligibility and comprehension scores for listeners with simulated ARHL are highly correlated with the performances of an ASR-based system. In the future, it needs to be determined if the ASR system is similarly successful in predicting speech processing in noise and by older people with ARHL.

Prototype to product—developing a commercially viable neural prosthesis

NASA Astrophysics Data System (ADS)

Seligman, Peter

2009-12-01

The Cochlear implant or 'Bionic ear' is a device that enables people who do not get sufficient benefit from a hearing aid to communicate with the hearing world. The Cochlear implant is not an amplifier, but a device that electrically stimulates the auditory nerve in a way that crudely mimics normal hearing, thus providing a hearing percept. Many recipients are able to understand running speech without the help of lipreading. Cochlear implants have reached a stage of maturity where there are now 170 000 recipients implanted worldwide. The commercial development of these devices has occurred over the last 30 years. This development has been multidisciplinary, including audiologists, engineers, both mechanical and electrical, histologists, materials scientists, physiologists, surgeons and speech pathologists. This paper will trace the development of the device we have today, from the engineering perspective. The special challenges of designing an active device that will work in the human body for a lifetime will be outlined. These challenges include biocompatibility, extreme reliability, safety, patient fitting and surgical issues. It is emphasized that the successful development of a neural prosthesis requires the partnership of academia and industry.

Prototype to product-developing a commercially viable neural prosthesis.

PubMed

Seligman, Peter

2009-12-01

The Cochlear implant or 'Bionic ear' is a device that enables people who do not get sufficient benefit from a hearing aid to communicate with the hearing world. The Cochlear implant is not an amplifier, but a device that electrically stimulates the auditory nerve in a way that crudely mimics normal hearing, thus providing a hearing percept. Many recipients are able to understand running speech without the help of lipreading. Cochlear implants have reached a stage of maturity where there are now 170 000 recipients implanted worldwide. The commercial development of these devices has occurred over the last 30 years. This development has been multidisciplinary, including audiologists, engineers, both mechanical and electrical, histologists, materials scientists, physiologists, surgeons and speech pathologists. This paper will trace the development of the device we have today, from the engineering perspective. The special challenges of designing an active device that will work in the human body for a lifetime will be outlined. These challenges include biocompatibility, extreme reliability, safety, patient fitting and surgical issues. It is emphasized that the successful development of a neural prosthesis requires the partnership of academia and industry.

(PURPA grants to state utility regulatory commissions and electric utilities). Final report

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

Lambert, E.S.

The Utah Commission considered fully in hearings each of the eleven regulatory and ratemaking standards. In addition, the Commission held hearings concerning the lifeline rates provision of PURPA and the cogeneration and small power production provision. The Utah Commission has taken action with respect to each of these standards. In its Order concerning cases numbered 80-999-09 and 81-999-01, 02, 03, 04, and 05, issued May 14, 1982, and appended to this report, the Utah Commission adopted each of the ratemaking standards. Its actions concerning adoption of the regulatory standards have been the subject of hearings and orders issued during themore » period of time prior to the issuance of the May 14, 1982 Order. After full hearing on the subject, the Utah Commission declined to adopt lifeline rates. In an Order issued April 9, 1981, the Commission implemented the FERC regulations issued pursuant to PURPA Sections 201 and 210. Contained in that Order were interim rates based upon the avoided costs of the electric utilities under this Commission's jurisdiction that are subject to PURPA.« less

Binaural hearing with electrical stimulation

PubMed Central

Kan, Alan; Litovsky, Ruth Y.

2014-01-01

Bilateral cochlear implantation is becoming a standard of care in many clinics. While much benefit has been shown through bilateral implantation, patients who have bilateral cochlear implants (CIs) still do not perform as well as normal hearing listeners in sound localization and understanding speech in noisy environments. This difference in performance can arise from a number of different factors, including the areas of hardware and engineering, surgical precision and pathology of the auditory system in deaf persons. While surgical precision and individual pathology are factors that are beyond careful control, improvements can be made in the areas of clinical practice and the engineering of binaural speech processors. These improvements should be grounded in a good understanding of the sensitivities of bilateral CI patients to the acoustic binaural cues that are important to normal hearing listeners for sound localization and speech in noise understanding. To this end, we review the current state-of-the-art in the understanding of the sensitivities of bilateral CI patients to binaural cues in electric hearing, and highlight the important issues and challenges as they relate to clinical practice and the development of new binaural processing strategies. PMID:25193553

Auditory and tactile gap discrimination by observers with normal and impaired hearing.

PubMed

Desloge, Joseph G; Reed, Charlotte M; Braida, Louis D; Perez, Zachary D; Delhorne, Lorraine A; Villabona, Timothy J

2014-02-01

Temporal processing ability for the senses of hearing and touch was examined through the measurement of gap-duration discrimination thresholds (GDDTs) employing the same low-frequency sinusoidal stimuli in both modalities. GDDTs were measured in three groups of observers (normal-hearing, hearing-impaired, and normal-hearing with simulated hearing loss) covering an age range of 21-69 yr. GDDTs for a baseline gap of 6 ms were measured for four different combinations of 100-ms leading and trailing markers (250-250, 250-400, 400-250, and 400-400 Hz). Auditory measurements were obtained for monaural presentation over headphones and tactile measurements were obtained using sinusoidal vibrations presented to the left middle finger. The auditory GDDTs of the hearing-impaired listeners, which were larger than those of the normal-hearing observers, were well-reproduced in the listeners with simulated loss. The magnitude of the GDDT was generally independent of modality and showed effects of age in both modalities. The use of different-frequency compared to same-frequency markers led to a greater deterioration in auditory GDDTs compared to tactile GDDTs and may reflect differences in bandwidth properties between the two sensory systems.

76 FR 23768 - National Emission Standards for Hazardous Air Pollutants From Coal- and Oil-Fired Electric...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-28

...-Fired Electric Utility Steam Generating Units and Standards of Performance for Fossil-Fuel-Fired... Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial... copy form. The hearing schedules, including lists of speakers, will be posted on EPA's Web Sites http...

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

PubMed

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

2016-01-01

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

Impulse noise generator--design and operation.

PubMed

Brinkmann, H

1991-01-01

In the seventies PFANDER (Pfander, 1975) proposed a screening test with an impulse noise simulator to check the particular responsivity of soldiers on vulnerability of the inner ear concerning the impulse noise-induced hearing loss. According to a system developed at the University of Oldenburg (Germany) (Klug & Radek, 1987), we have constructed an impulse noise generator designed for our specific requirements that will be presented. The simulator consists of an electrical ignited impulse noise spark gap which is supplied by a 3.5 kV high voltage source. At a distance of 1.10 m from the center of the impulse noise spark gap a peak pressure level of 155 dB with a C-Duration (Pfander, 1975) of .2 msec and with the main energy in the frequency range from 1 kHz to 2 kHz was good reproducible. It would be preferable to shift the impulse noise spectrum to lower frequencies but experimental effort has failed so far.

Congenital hearing loss

PubMed Central

Korver, Anna M. H.; Smith, Richard J. H.; Van Camp, Guy; Schleiss, Mark R.; Bitner-Glindzicz, Maria A. K.; Lustig, Lawrence R.; Usami, Shin-ichi; Boudewyns, An N.

2017-01-01

Congenital hearing loss (hearing loss present at birth) is one of the most prevalent chronic conditions in children. In the majority of developed countries, neonatal hearing-screening programmes enable early detection; early intervention will prevent delays in speech and language development and have long-lasting beneficial effects on social and emotional development and quality of life. A hearing loss diagnosis is usually followed by a search for an underlying aetiology. Congenital hearing loss might be attributed to environmental and prenatal factors, which prevail in low-income settings; congenital infections, particularly cytomegalovirus, are also a common risk factor for hearing loss. Genetic causes probably account for the majority of cases in developed countries; mutations can affect any component of the hearing pathway, in particular inner ear homeostasis (endolymph production and maintenance) and mechano-electrical transduction (conversion of a mechanical stimulus into electrochemical activity). Once the underlying cause of hearing loss is established, it might direct therapeutic decision-making and guide prevention and (genetic) counseling. Management options include specific antimicrobial therapies, surgical treatment of cranio-facial abnormalities and hearing aids. An improved understanding of the pathophysiology and molecular mechanisms underlying hearing loss and increased awareness of recent advances in genetic testing will promote the development of new treatment and screening strategies. PMID:28079113

Speech perception in noise with a harmonic complex excited vocoder.

PubMed

Churchill, Tyler H; Kan, Alan; Goupell, Matthew J; Ihlefeld, Antje; Litovsky, Ruth Y

2014-04-01

A cochlear implant (CI) presents band-pass-filtered acoustic envelope information by modulating current pulse train levels. Similarly, a vocoder presents envelope information by modulating an acoustic carrier. By studying how normal hearing (NH) listeners are able to understand degraded speech signals with a vocoder, the parameters that best simulate electric hearing and factors that might contribute to the NH-CI performance difference may be better understood. A vocoder with harmonic complex carriers (fundamental frequency, f0 = 100 Hz) was used to study the effect of carrier phase dispersion on speech envelopes and intelligibility. The starting phases of the harmonic components were randomly dispersed to varying degrees prior to carrier filtering and modulation. NH listeners were tested on recognition of a closed set of vocoded words in background noise. Two sets of synthesis filters simulated different amounts of current spread in CIs. Results showed that the speech vocoded with carriers whose starting phases were maximally dispersed was the most intelligible. Superior speech understanding may have been a result of the flattening of the dispersed-phase carrier's intrinsic temporal envelopes produced by the large number of interacting components in the high-frequency channels. Cross-correlogram analyses of auditory nerve model simulations confirmed that randomly dispersing the carrier's component starting phases resulted in better neural envelope representation. However, neural metrics extracted from these analyses were not found to accurately predict speech recognition scores for all vocoded speech conditions. It is possible that central speech understanding mechanisms are insensitive to the envelope-fine structure dichotomy exploited by vocoders.

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

PubMed

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

2018-05-17

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

Morphological Correlates of Hearing Loss after Cochlear Implantation and Electro-Acoustic Stimulation in a Hearing-Impaired Guinea Pig Model

PubMed Central

Reiss, Lina A.J.; Stark, Gemaine; Nguyen-Huynh, Anh T.; Spear, Kayce A.; Zhang, Hongzheng; Tanaka, Chiemi; Li, Hongzhe

2016-01-01

Hybrid or electro-acoustic stimulation (EAS) cochlear implants (CIs) are designed to provide high-frequency electric hearing together with residual low-frequency acoustic hearing. However, 30-50% of EAS CI recipients lose residual hearing after implantation. The objective of this study was to determine the mechanisms of EAS-induced hearing loss in an animal model with high-frequency hearing loss. Guinea pigs were exposed to 24 hours of noise (12-24 kHz at 116 dB) to induce a high-frequency hearing loss. After recovery, two groups of animals were implanted (n=6 per group), with one group receiving chronic acoustic and electric stimulation for 10 weeks, and the other group receiving no stimulation during this time frame. A third group (n=6) was not implanted, but received chronic acoustic stimulation. Auditory brainstem responses were recorded biweekly to monitor changes in hearing. The organ of Corti was immunolabeled with phalloidin, anti-CtBP2, and anti-GluR2 to quantify hair cells, ribbons and post-synaptic receptors. The lateral wall was immunolabeled with phalloidin and lectin to quantify stria vascularis capillary diameters. Bimodal or trimodal diameter distributions were observed; the number and location of peaks were objectively determined using the Aikake Information Criterion and Expectation Maximization algorithm. Noise exposure led to immediate hearing loss at 16-32 kHz for all groups. Cochlear implantation led to additional hearing loss at 4-8 kHz; this hearing loss was negatively and positively correlated with minimum and maximum peaks of the bimodal or trimodal distributions of stria vascularis capillary diameters, respectively. After chronic stimulation, no significant group changes in thresholds were seen; however, elevated thresholds at 1 kHz in implanted, stimulated animals were significantly correlated with decreased presynaptic ribbon and postsynaptic receptor counts. Inner and outer hair cell counts did not differ between groups and were not correlated with threshold shifts at any frequency. As in the previous study in a normal-hearing model, stria vascularis capillary changes were associated with immediate hearing loss after implantation, while little to no hair cell loss was observed even in cochlear regions with threshold shifts as large as 40-50 dB. These findings again support a role of lateral wall blood flow changes, rather than hair cell loss, in hearing loss after surgical trauma, and implicate the endocochlear potential as a factor in implantation-induced hearing loss. Further, the analysis of the hair cell ribbons and post-synaptic receptors suggest that delayed hearing loss may be linked to synapse or peripheral nerve loss due to stimulation excitotoxicity or inflammation. Further research is needed to separate these potential mechanisms of delayed hearing loss. PMID:26087114

The Problem of Feedback in Hearing Aids.

ERIC Educational Resources Information Center

Kates, James M.

1991-01-01

This paper discusses the problem of feedback in hearing aids and offers examples based on a computer simulation of hearing aid behavior. The available technology for dealing with feedback is reviewed, and the new digital signal-processing approaches which may finally solve the feedback problem are described. (Author/DB)

Implications of Minimizing Trauma During Conventional Cochlear Implantation

PubMed Central

Carlson, Matthew L.; Driscoll, Colin L. W.; Gifford, René H.; Service, Geoffrey J.; Tombers, Nicole M.; Hughes-Borst, Becky J.; Neff, Brian A.; Beatty, Charles W.

2014-01-01

Objective To describe the relationship between implantation-associated trauma and postoperative speech perception scores among adult and pediatric patients undergoing cochlear implantation using conventional length electrodes and minimally traumatic surgical techniques. Study Design Retrospective chart review (2002–2010). Setting Tertiary academic referral center. Patients All subjects with significant preoperative low-frequency hearing (≤70 dB HL at 250 Hz) who underwent cochlear implantation with a newer generation implant electrode (Nucleus Contour Advance, Advanced Bionics HR90K [1J and Helix], and Med El Sonata standard H array) were reviewed. Intervention(s) Preimplant and postimplant audiometric thresholds and speech recognition scores were recorded using the electronic medical record. Main Outcome Measure(s) Postimplantation pure tone threshold shifts were used as a surrogate measure for extent of intracochlear injury and correlated with postoperative speech perception scores. Results Between 2002 and 2010, 703 cochlear implant (CI) operations were performed. Data from 126 implants were included in the analysis. The mean preoperative low-frequency pure-tone average was 55.4 dB HL. Hearing preservation was observed in 55% of patients. Patients with hearing preservation were found to have significantly higher postoperative speech perception performance in the cochlear implantation-only condition than those who lost all residual hearing. Conclusion Conservation of acoustic hearing after conventional length cochlear implantation is unpredictable but remains a realistic goal. The combination of improved technology and refined surgical technique may allow for conservation of some residual hearing in more than 50% of patients. Germane to the conventional length CI recipient with substantial hearing loss, minimizing trauma allows for improved speech perception in the electric condition. These findings support the use of minimally traumatic techniques in all CI recipients, even those destined for electric-only stimulation. PMID:21659922

Identifying emotions in music through electrical hearing in deaf children using cochlear implants.

PubMed

Hopyan, T; Gordon, K A; Papsin, B C

2011-02-01

Cochlear implant (CI) devices are the choice of treatment for individuals with severe to profound hearing loss. The CI devices provide the opportunity for children who are deaf to perceive sound by electrical stimulation of the auditory nerve, with the goal of optimizing oral communication. A natural benefit of acquiring hearing using CIs is the ability to hear, and perhaps enjoy, music. Music is a non-verbal auditory stimulus and a powerful tool for transmitting emotion. Identifying emotional cues is an important part of normal social development and communication and thus music may play an important role in establishing these skills during development. To date, it is not known whether children who use cochlear implants to hear can identify the emotional content carried in music. Our objective in the present study was to determine whether children who have been deaf from infancy and are experienced CI users have acquired the ability to identify emotion in musical phrases. Study participants were 18 CI users (ages 7-13 years) who received right unilateral CIs (mean age at CI activation of 2.9 years) and 18 age-and gender-matched controls. Participants were asked to judge 32 brief musical excerpts as happy or sad by pointing to simple graphics of a smiling or frowning face. Children using CIs were able to correctly distinguish happy versus sad music well above chance levels, but performed more poorly on this task than their peers with typical hearing. Age at CI activation and time since CI activation were both uncorrelated with outcome measures. Children with CIs show the ability to perceive emotion in music but do so less accurately than typically hearing peers.

The Master Hearing Aid

PubMed Central

Curran, James R.

2013-01-01

As early as the 1930s the term Master Hearing Aid (MHA) described a device used in the fitting of hearing aids. In their original form, the MHA was a desktop system that allowed for simulated or actual adjustment of hearing aid components that resulted in a changed hearing aid response. Over the years the MHA saw many embodiments and contributed to a number of rationales for the fitting of hearing aids. During these same years, the MHA was viewed by many as an inappropriate means of demonstrating hearing aids; the audio quality of the desktop systems was often superior to the hearing aids themselves. These opinions and the evolution of the MHA have molded the modern perception of hearing aids and the techniques used in the fitting of hearing aids. This article reports on a history of the MHA and its influence on the fitting of hearing aids. PMID:23686682

Electronic filters, repeated signal charge conversion apparatus, hearing aids and methods

NASA Technical Reports Server (NTRS)

Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

1993-01-01

An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed.

Hearing Preservation Outcomes After Cochlear Implantation Depending on the Angle of Insertion: Indication for Electric or Electric-Acoustic Stimulation.

PubMed

Helbig, Silke; Adel, Youssef; Leinung, Martin; Stöver, Timo; Baumann, Uwe; Weissgerber, Tobias

2018-06-15

This study reviewed outcomes of hearing preservation (HP) surgery depending on the angle of insertion (AOI) in a cochlear implant (CI) patient population who used electric stimulation (ES) or combined electric-acoustic stimulation (EAS). Retrospective case review. Tertiary referral university hospital. Ninety-one patients with different degrees of preoperative low-frequency residual hearing who underwent HP surgery with a free-fitting lateral-wall electrode array (MED-EL Flex) with lengths ranging from 20.0 to 31.5 mm. Cochlear implantation using HP surgery technique and subsequent fitting with CI speech processor for ES, or combined CI and hearing aid speech processor for EAS. Individual AOI were estimated using modified Stenvers' projection. Freiburg monosyllable test in quiet (free-field presentation at 65 dB SPL) and pure-tone averages for low frequencies (125, 250, and 500 Hz; PTAlow) were evaluated during a follow-up period of 12 months after implantation. Estimated AOIs showed bimodal distribution: shallow insertion (SI) with mean AOI of 377 degrees and deep insertion (DI) with mean AOI of 608 degrees. Speech test scores after 12 months were comparable between AOI groups, however, they were significantly different between stimulation types with better scores for EAS. Only ES showed a positive correlation (r = 0.293) between speech test score and AOI. When HP was possible, both SI and DI showed significant postoperative PTAlow shifts with mean of 17.8 and 21.6 dB, respectively. These were comparable between AOI groups and no significant shifts were observed in follow-up intervals. Audiometric indication for HP and subsequent EAS is proposed up to 65 dB HL at 500 Hz, and up to 87 dB HL for HP. CI candidates can benefit from HP surgery with deep insertion when only using ES due to insufficient residual hearing. Conversely, candidates with preoperative threshold up to 65 dB HL at 500 Hz could perform significantly better with EAS which requires shallow insertion.

Biophysical Mechanisms Underlying Hearing Loss Associated with a Shortened Tectorial Membrane

NASA Astrophysics Data System (ADS)

Oghalai, John S.; Xia, Anping; Liu, Christopher C.; Gao, Simon S.; Applegate, Brian E.; Puria, Sunil; Rousso, Itay; Steele, Charles

2011-11-01

The tectorial membrane (TM) connects to the stereociliary bundles of outer hair cells (OHCs). Herein, we summarize key experimental data and modeling analyses that describe how biophysical alterations to these connections underlie hearing loss. The heterozygous C1509G mutation in alpha tectorin produces partial congenital hearing loss that progresses in humans. We engineered this mutation in mice, and histology revealed that the TM was shortened. DIC imaging of freshly-dissected cochlea as well as imaging with optical coherence tomography indicated that the TM is malformed and only stimulates the first row of OHCs. Noise exposure produced acute threshold shifts that fully recovered in Tecta+/+ mice although there was some OHC loss within all three rows at the cochlear base. In contrast, threshold shifts only partially recovered in TectaC1509G/+ mice. This was associated with OHC loss more apically and nearly entirely within the first row. Young's modulus of the TM, measured using atomic force microscopy, was substantially reduced at the middle and basal regions. Both the wild-type and heterozygous conditions were simulated in a computational model. This demonstrated that the normalized stress distribution levels between the TM and the tall cilia were significantly elevated in the middle region of the heterozygous cochlea. Another feature of the TectaC1509G/+ mutation is higher prestin expression within all three rows of OHCs. This increased electricallyevoked movements of the reticular lamina and otoacoustic emissions. Furthermore, electrical stimulation was associated with an increased risk of OHC death as measured by vital dye staining. Together, these findings indicate that uncoupling of the TM from some OHCs not only leads to partial hearing loss, but also puts the OHCs that remain coupled at higher risk. Both the mechanics of the malformed TM and increased electromotility contribute to this higher risk profile.

Automatic Speech Recognition Predicts Speech Intelligibility and Comprehension for Listeners with Simulated Age-Related Hearing Loss

ERIC Educational Resources Information Center

Fontan, Lionel; Ferrané, Isabelle; Farinas, Jérôme; Pinquier, Julien; Tardieu, Julien; Magnen, Cynthia; Gaillard, Pascal; Aumont, Xavier; Füllgrabe, Christian

2017-01-01

Purpose: The purpose of this article is to assess speech processing for listeners with simulated age-related hearing loss (ARHL) and to investigate whether the observed performance can be replicated using an automatic speech recognition (ASR) system. The long-term goal of this research is to develop a system that will assist…

Inner ear damage following electric current and lightning injury: a literature review.

PubMed

Modayil, P C; Lloyd, G W; Mallik, A; Bowdler, D A

2014-05-01

Audiovestibular sequelae of electrical injury, due to lightning or electric current, are probably much more common than indicated in literature. The aim of the study was to review the impact of electrical injury on the cochleovestibular system. Studies were identified through Medline, Embase, CINAHL and eMedicine databases. Medical Subject Headings used were 'electrical injury', 'lightning', 'deafness' and 'vertigo'. All prospective and retrospective studies, case series and case reports of patients with cochlear or vestibular damage due to lightning or electrical current injury were included. Studies limited to external and middle ear injuries were excluded. Thirty-five articles met the inclusion criteria. Fifteen reported audiovestibular damage following electric current injury (domestic or industrial); a further 15 reported lightning injuries and five concerned pathophysiology and management. There were no histological studies of electrical current injury to the human audiovestibular system. The commonest acoustic insult after lightning injury is conductive hearing loss secondary to tympanic membrane rupture and the most frequent vestibular symptom is transient vertigo. Electrical current injuries predominantly cause pure sensorineural hearing loss and may significantly increase a patient's lifetime risk of vertigo. Theories for cochleovestibular damage in electrical injury include disruption of inner ear anatomy, electrical conductance, hypoxia, vascular effects and stress response hypothesis. The pathophysiology of cochleovestibular damage following electrical injury is unresolved. The mechanism of injury following lightning strike is likely to be quite different from that following domestic or industrial electrical injury. The formulation of an audiovestibular management protocol for patients who have suffered electrical injuries and systematic reporting of all such events is recommended.

Morphological correlates of hearing loss after cochlear implantation and electro-acoustic stimulation in a hearing-impaired Guinea pig model.

PubMed

Reiss, Lina A J; Stark, Gemaine; Nguyen-Huynh, Anh T; Spear, Kayce A; Zhang, Hongzheng; Tanaka, Chiemi; Li, Hongzhe

2015-09-01

Hybrid or electro-acoustic stimulation (EAS) cochlear implants (CIs) are designed to provide high-frequency electric hearing together with residual low-frequency acoustic hearing. However, 30-50% of EAS CI recipients lose residual hearing after implantation. The objective of this study was to determine the mechanisms of EAS-induced hearing loss in an animal model with high-frequency hearing loss. Guinea pigs were exposed to 24 h of noise (12-24 kHz at 116 dB) to induce a high-frequency hearing loss. After recovery, two groups of animals were implanted (n = 6 per group), with one group receiving chronic acoustic and electric stimulation for 10 weeks, and the other group receiving no stimulation during this time frame. A third group (n = 6) was not implanted, but received chronic acoustic stimulation. Auditory brainstem responses were recorded biweekly to monitor changes in hearing. The organ of Corti was immunolabeled with phalloidin, anti-CtBP2, and anti-GluR2 to quantify hair cells, ribbons and post-synaptic receptors. The lateral wall was immunolabeled with phalloidin and lectin to quantify stria vascularis capillary diameters. Bimodal or trimodal diameter distributions were observed; the number and location of peaks were objectively determined using the Aikake Information Criterion and Expectation Maximization algorithm. Noise exposure led to immediate hearing loss at 16-32 kHz for all groups. Cochlear implantation led to additional hearing loss at 4-8 kHz; this hearing loss was negatively and positively correlated with minimum and maximum peaks of the bimodal or trimodal distributions of stria vascularis capillary diameters, respectively. After chronic stimulation, no significant group changes in thresholds were seen; however, elevated thresholds at 1 kHz in implanted, stimulated animals were significantly correlated with decreased presynaptic ribbon and postsynaptic receptor counts. Inner and outer hair cell counts did not differ between groups and were not correlated with threshold shifts at any frequency. As in the previous study in a normal-hearing model, stria vascularis capillary changes were associated with immediate hearing loss after implantation, while little to no hair cell loss was observed even in cochlear regions with threshold shifts as large as 40-50 dB. These findings again support a role of lateral wall blood flow changes, rather than hair cell loss, in hearing loss after surgical trauma, and implicate the endocochlear potential as a factor in implantation-induced hearing loss. Further, the analysis of the hair cell ribbons and post-synaptic receptors suggest that delayed hearing loss may be linked to synapse or peripheral nerve loss due to stimulation excitotoxicity or inflammation. Further research is needed to separate these potential mechanisms of delayed hearing loss. Copyright © 2015 Elsevier B.V. All rights reserved.

Exploration of a physiologically-inspired hearing-aid algorithm using a computer model mimicking impaired hearing.

PubMed

Jürgens, Tim; Clark, Nicholas R; Lecluyse, Wendy; Meddis, Ray

2016-01-01

To use a computer model of impaired hearing to explore the effects of a physiologically-inspired hearing-aid algorithm on a range of psychoacoustic measures. A computer model of a hypothetical impaired listener's hearing was constructed by adjusting parameters of a computer model of normal hearing. Absolute thresholds, estimates of compression, and frequency selectivity (summarized to a hearing profile) were assessed using this model with and without pre-processing the stimuli by a hearing-aid algorithm. The influence of different settings of the algorithm on the impaired profile was investigated. To validate the model predictions, the effect of the algorithm on hearing profiles of human impaired listeners was measured. A computer model simulating impaired hearing (total absence of basilar membrane compression) was used, and three hearing-impaired listeners participated. The hearing profiles of the model and the listeners showed substantial changes when the test stimuli were pre-processed by the hearing-aid algorithm. These changes consisted of lower absolute thresholds, steeper temporal masking curves, and sharper psychophysical tuning curves. The hearing-aid algorithm affected the impaired hearing profile of the model to approximate a normal hearing profile. Qualitatively similar results were found with the impaired listeners' hearing profiles.

Labyrinthectomy with cochlear implantation.

PubMed

Zwolan, T A; Shepard, N T; Niparko, J K

1993-05-01

Numerous reports indicate that the cochlea remains responsive to electrical stimulation following labyrinthectomy. We report a case of a 47-year-old woman with a severe to profound sensorineural hearing loss from birth, who developed episodic vertigo with symptoms suggestive of delayed onset endolymphatic hydrops. Following 8 months of failed medical and vestibular rehabilitation management, a right-sided labyrinthectomy combined with cochlear implantation was performed without complication. Postoperatively the patient was free of vertigo. Attempts to activate the patient's device between 4 to 12 weeks after surgery were unsuccessful as stimulation of the electrodes resulted in discomfort. However, all 20 electrodes elicited comfortable hearing sensations 16 weeks postsurgery. One year after the successful activation, the patient demonstrated improved sound awareness and speech recognition with the implant when compared with preoperative performance with a hearing aid. This case study suggests that electrical detection thresholds with prosthetic stimulation may be unstable in the recently labyrinthectomized ear but supports and extends prior observations of preserved cochlear responsiveness after labyrinthectomy.

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

PubMed

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

2013-01-01

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

A system to simulate and reproduce audio-visual environments for spatial hearing research.

PubMed

Seeber, Bernhard U; Kerber, Stefan; Hafter, Ervin R

2010-02-01

The article reports the experience gained from two implementations of the "Simulated Open-Field Environment" (SOFE), a setup that allows sounds to be played at calibrated levels over a wide frequency range from multiple loudspeakers in an anechoic chamber. Playing sounds from loudspeakers in the free-field has the advantage that each participant listens with their own ears, and individual characteristics of the ears are captured in the sound they hear. This makes an easy and accurate comparison between various listeners with and without hearing devices possible. The SOFE uses custom calibration software to assure individual equalization of each loudspeaker. Room simulation software creates the spatio-temporal reflection pattern of sound sources in rooms which is played via the SOFE loudspeakers. The sound playback system is complemented by a video projection facility which can be used to collect or give feedback or to study auditory-visual interaction. The article discusses acoustical and technical requirements for accurate sound playback against the specific needs in hearing research. An introduction to software concepts is given which allow easy, high-level control of the setup and thus fast experimental development, turning the SOFE into a "Swiss army knife" tool for auditory, spatial hearing and audio-visual research. Crown Copyright 2009. Published by Elsevier B.V. All rights reserved.

A System to Simulate and Reproduce Audio-Visual Environments for Spatial Hearing Research

PubMed Central

Seeber, Bernhard U.; Kerber, Stefan; Hafter, Ervin R.

2009-01-01

The article reports the experience gained from two implementations of the “Simulated Open-Field Environment” (SOFE), a setup that allows sounds to be played at calibrated levels over a wide frequency range from multiple loudspeakers in an anechoic chamber. Playing sounds from loudspeakers in the free-field has the advantage that each participant listens with their own ears, and individual characteristics of the ears are captured in the sound they hear. This makes an easy and accurate comparison between various listeners with and without hearing devices possible. The SOFE uses custom calibration software to assure individual equalization of each loudspeaker. Room simulation software creates the spatio-temporal reflection pattern of sound sources in rooms which is played via the SOFE loudspeakers. The sound playback system is complemented by a video projection facility which can be used to collect or give feedback or to study auditory-visual interaction. The article discusses acoustical and technical requirements for accurate sound playback against the specific needs in hearing research. An introduction to software concepts is given which allow easy, high-level control of the setup and thus fast experimental development, turning the SOFE into a “Swiss army knife” tool for auditory, spatial hearing and audio-visual research. PMID:19909802

Illegal, Unethical or Just Fattening? A Revisionist Look at the FTC Hearings on Electric Utility Public Relations and Franklin Roosevelt's 1932 Public Power Pledge.

ERIC Educational Resources Information Center

Jordan, Myron K.

Did President Franklin D. Roosevelt's condemnation of electric utility public relations represent a fair interpretation of the findings of the Federal Trade Commission (FTC) investigation into the electric utility industry as authorized by Senate Resolution 83 in February, 1928, or were Roosevelt's statements simply campaign hyperbole that met the…

Top-down Processes in Simulated Electric-Acoustic Hearing: The Effect of Linguistic Context on Bimodal Benefit for Temporally Interrupted Speech

PubMed Central

Oh, Soo Hee; Donaldson, Gail S.; Kong, Ying-Yee

2016-01-01

Objectives Previous studies have documented the benefits of bimodal hearing as compared with a CI alone, but most have focused on the importance of bottom-up, low-frequency cues. The purpose of the present study was to evaluate the role of top-down processing in bimodal hearing by measuring the effect of sentence context on bimodal benefit for temporally interrupted sentences. It was hypothesized that low-frequency acoustic cues would facilitate the use of contextual information in the interrupted sentences, resulting in greater bimodal benefit for the higher context (CUNY) sentences than for the lower context (IEEE) sentences. Design Young normal-hearing listeners were tested in simulated bimodal listening conditions in which noise band vocoded sentences were presented to one ear with or without low-pass (LP) filtered speech or LP harmonic complexes (LPHCs) presented to the contralateral ear. Speech recognition scores were measured in three listening conditions: vocoder-alone, vocoder combined with LP speech, and vocoder combined with LPHCs. Temporally interrupted versions of the CUNY and IEEE sentences were used to assess listeners’ ability to fill in missing segments of speech by using top-down linguistic processing. Sentences were square-wave gated at a rate of 5 Hz with a 50 percent duty cycle. Three vocoder channel conditions were tested for each type of sentence (8, 12, and 16 channels for CUNY; 12, 16, and 32 channels for IEEE) and bimodal benefit was compared for similar amounts of spectral degradation (matched-channel comparisons) and similar ranges of baseline performance. Two gain measures, percentage-point gain and normalized gain, were examined. Results Significant effects of context on bimodal benefit were observed when LP speech was presented to the residual-hearing ear. For the matched-channel comparisons, CUNY sentences showed significantly higher normalized gains than IEEE sentences for both the 12-channel (20 points higher) and 16-channel (18 points higher) conditions. For the individual gain comparisons that used a similar range of baseline performance, CUNY sentences showed bimodal benefits that were significantly higher (7 percentage points, or 15 points normalized gain) than those for IEEE sentences. The bimodal benefits observed here for temporally interrupted speech were considerably smaller than those observed in an earlier study that used continuous speech (Kong et al., 2015). Further, unlike previous findings for continuous speech, no bimodal benefit was observed when LPHCs were presented to the LP ear. Conclusions Findings indicate that linguistic context has a significant influence on bimodal benefit for temporally interrupted speech and support the hypothesis that low-frequency acoustic information presented to the residual-hearing ear facilitates the use of top-down linguistic processing in bimodal hearing. However, bimodal benefit is reduced for temporally interrupted speech as compared to continuous speech, suggesting that listeners’ ability to restore missing speech information depends not only on top-down linguistic knowledge, but also on the quality of the bottom-up sensory input. PMID:27007220

20 CFR 301.1 - Statutory provisions.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., interurban, or suburban electric railway, unless such railway is operating as a part of a general steam... after hearing whether any line operated by electric power falls within the terms of this proviso. The... therefor, or in any of such activities. * * * (b) The term “carrier” means an express company, sleeping-car...

20 CFR 301.1 - Statutory provisions.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., interurban, or suburban electric railway, unless such railway is operating as a part of a general steam... after hearing whether any line operated by electric power falls within the terms of this proviso. The... therefor, or in any of such activities. * * * (b) The term “carrier” means an express company, sleeping-car...

20 CFR 301.1 - Statutory provisions.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., interurban, or suburban electric railway, unless such railway is operating as a part of a general steam... after hearing whether any line operated by electric power falls within the terms of this proviso. The... therefor, or in any of such activities. * * * (b) The term “carrier” means an express company, sleeping-car...

20 CFR 301.1 - Statutory provisions.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., interurban, or suburban electric railway, unless such railway is operating as a part of a general steam... after hearing whether any line operated by electric power falls within the terms of this proviso. The... therefor, or in any of such activities. * * * (b) The term “carrier” means an express company, sleeping-car...

20 CFR 301.1 - Statutory provisions.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., interurban, or suburban electric railway, unless such railway is operating as a part of a general steam... after hearing whether any line operated by electric power falls within the terms of this proviso. The... therefor, or in any of such activities. * * * (b) The term “carrier” means an express company, sleeping-car...

Ipsilateral masking between acoustic and electric stimulations.

PubMed

Lin, Payton; Turner, Christopher W; Gantz, Bruce J; Djalilian, Hamid R; Zeng, Fan-Gang

2011-08-01

Residual acoustic hearing can be preserved in the same ear following cochlear implantation with minimally traumatic surgical techniques and short-electrode arrays. The combined electric-acoustic stimulation significantly improves cochlear implant performance, particularly speech recognition in noise. The present study measures simultaneous masking by electric pulses on acoustic pure tones, or vice versa, to investigate electric-acoustic interactions and their underlying psychophysical mechanisms. Six subjects, with acoustic hearing preserved at low frequencies in their implanted ear, participated in the study. One subject had a fully inserted 24 mm Nucleus Freedom array and five subjects had Iowa/Nucleus hybrid implants that were only 10 mm in length. Electric masking data of the long-electrode subject showed that stimulation from the most apical electrodes produced threshold elevations over 10 dB for 500, 625, and 750 Hz probe tones, but no elevation for 125 and 250 Hz tones. On the contrary, electric stimulation did not produce any electric masking in the short-electrode subjects. In the acoustic masking experiment, 125-750 Hz pure tones were used to acoustically mask electric stimulation. The acoustic masking results showed that, independent of pure tone frequency, both long- and short-electrode subjects showed threshold elevations at apical and basal electrodes. The present results can be interpreted in terms of underlying physiological mechanisms related to either place-dependent peripheral masking or place-independent central masking.

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

PubMed

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

2012-01-01

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

Hearing parameters in noise exposed industrial workers.

PubMed

Celik, O; Yalçin, S; Oztürk, A

1998-12-01

This paper presents the results of a study carried out in a group of noise-exposed workers in a hydro-electric power plant. Thus, the main focus of the study is on 130 industrial workers who were exposed to high level of noise. The control group was consisted of 33 subjects with normal hearing. Hearing and acoustic reflex thresholds were obtained from all subjects and the results from age-matched subgroups were compared. The sensorineural hearing loss which were detected in 71 workers were bilateral, symmetrical and affected mainly frequencies of 4-6 kHz. In essence, the hearing losses were developed within the first 10 years of noise exposure and associated with slight progress in the following years. When acoustic reflex thresholds derived from the study and control groups were compared, statistically significant difference was determined only for the thresholds obtained at 4 kHz (p < 0.0005).

Does cochlear implantation and electrical stimulation affect residual hair cells and spiral ganglion neurons?

PubMed Central

Coco, Anne; Epp, Stephanie B.; Fallon, James B.; Xu, Jin; Millard, Rodney E.; Shepherd, Robert K.

2007-01-01

Increasing numbers of cochlear implant subjects have some level of residual hearing at the time of implantation. The present study examined whether (i) hair cells that have survived one pathological insult (aminoglycoside deafening), can survive and function following long-term cochlear implantation and electrical stimulation (ES); and (ii) chronic ES in these cochleae results in greater trophic support of spiral ganglion neurons (SGNs) compared with cochleae devoid of hair cells. Eight cats, with either partial (n=4) or severe (n=4) sensorineural hearing loss, were bilaterally implanted with scala tympani electrode arrays 2 months after deafening, and received unilateral ES using charge balanced biphasic current pulses for periods of up to 235 days. Frequency-specific compound action potentials and click-evoked auditory brainstem responses (ABRs) were recorded periodically to monitor the residual acoustic hearing. Electrically-evoked ABRs (EABRs) were recorded to confirm the stimulus levels were 3-6 dB above the EABR threshold. On completion of the ES program the cochleae were examined histologically. Partially deafened animals showed no significant increase in acoustic thresholds over the implantation period. Moreover, chronic ES of an electrode array located in the base of the cochlea did not adversely affect hair cells in the middle or apical turns. There was evidence of a small but statistically significant rescue of SGNs in the middle and apical turns of stimulated cochleae in animals with partial hearing. Chronic ES did not, however, prevent a reduction in SGN density for the severely deaf cohort, although SGNs adjacent to the stimulating electrodes did exhibit a significant increase in soma area (p<0.01). In sum, chronic ES in partial hearing animals does not adversely affect functioning residual hair cells apical to the electrode array. Moreover, while there is an increase in the soma area of SGNs close to the stimulating electrodes in severely deaf cochleae, this trophic effect does not result in increased SGN survival. PMID:17258411

Trimodal speech perception: how residual acoustic hearing supplements cochlear-implant consonant recognition in the presence of visual cues.

PubMed

Sheffield, Benjamin M; Schuchman, Gerald; Bernstein, Joshua G W

2015-01-01

As cochlear implant (CI) acceptance increases and candidacy criteria are expanded, these devices are increasingly recommended for individuals with less than profound hearing loss. As a result, many individuals who receive a CI also retain acoustic hearing, often in the low frequencies, in the nonimplanted ear (i.e., bimodal hearing) and in some cases in the implanted ear (i.e., hybrid hearing) which can enhance the performance achieved by the CI alone. However, guidelines for clinical decisions pertaining to cochlear implantation are largely based on expectations for postsurgical speech-reception performance with the CI alone in auditory-only conditions. A more comprehensive prediction of postimplant performance would include the expected effects of residual acoustic hearing and visual cues on speech understanding. An evaluation of auditory-visual performance might be particularly important because of the complementary interaction between the speech information relayed by visual cues and that contained in the low-frequency auditory signal. The goal of this study was to characterize the benefit provided by residual acoustic hearing to consonant identification under auditory-alone and auditory-visual conditions for CI users. Additional information regarding the expected role of residual hearing in overall communication performance by a CI listener could potentially lead to more informed decisions regarding cochlear implantation, particularly with respect to recommendations for or against bilateral implantation for an individual who is functioning bimodally. Eleven adults 23 to 75 years old with a unilateral CI and air-conduction thresholds in the nonimplanted ear equal to or better than 80 dB HL for at least one octave frequency between 250 and 1000 Hz participated in this study. Consonant identification was measured for conditions involving combinations of electric hearing (via the CI), acoustic hearing (via the nonimplanted ear), and speechreading (visual cues). The results suggest that the benefit to CI consonant-identification performance provided by the residual acoustic hearing is even greater when visual cues are also present. An analysis of consonant confusions suggests that this is because the voicing cues provided by the residual acoustic hearing are highly complementary with the mainly place-of-articulation cues provided by the visual stimulus. These findings highlight the need for a comprehensive prediction of trimodal (acoustic, electric, and visual) postimplant speech-reception performance to inform implantation decisions. The increased influence of residual acoustic hearing under auditory-visual conditions should be taken into account when considering surgical procedures or devices that are intended to preserve acoustic hearing in the implanted ear. This is particularly relevant when evaluating the candidacy of a current bimodal CI user for a second CI (i.e., bilateral implantation). Although recent developments in CI technology and surgical techniques have increased the likelihood of preserving residual acoustic hearing, preservation cannot be guaranteed in each individual case. Therefore, the potential gain to be derived from bilateral implantation needs to be weighed against the possible loss of the benefit provided by residual acoustic hearing.

Oversight hearings on P. L. 93-577, ERDA Plan and Program. Hearings before the Subcommittee on Energy Research, Development and Demonstration of the Committee on Science and Technology, U. S. House of Representatives, Ninety-Fourth Congress, Second Session

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

Not Available

1976-01-01

The purpose of the hearings was to examine the comprehensive plan and program for dealing with energy that ERDA submitted to Congress on June 30, 1975. Included as an appendix to these hearings is the October 1975 report of the Office of Technology Assessment (OTA) entitled, ''An Analysis of the ERDA Plan and Program'' (for abstract of this report, see EAPA 2:79). Testifying on Jan. 22 was the director of OTA, Emilio Q. Daddario, and chairmen of various task groups that assisted in the ERDA analysis, namely: Dr. John Gibbons, Conservation; Dr. Paul Craig, Overview Panel; Dr. Alvin Weinberg, Nuclear;more » Dr. Stanford S. Penner, Environmental and Health; and Dr. Jerry Grey, Solar; also present, and participating in the question and answer portion was Lionel Johns, head of the energy projects and programs in OTA. Testifying at the Jan. 23 hearings were experts presenting environmental, scientific, and engineering viewpoints, namely: Dr. Donald McDonald, director of the environmental studies program at Dartmouth College; Dr. Reginald Vachon, Auburn University, representing the American Society of Mechanical Engineers; and Dr. Thomas Lee, General Electric Co., representing the Inst. of Electrical and Electronics Engineers. The final hearings on Jan. 29 included the testimony of Dr. Robert W. Fri, Deputy Administrator, ERDA, and that of each of five assistant administrators: Dr. John Teem, Solar, Geothermal, and Advanced Energy Systems; Dr. Austin Heller, Conservation; Dr. Richard W. Roberts, Nuclear Energy; Dr. Roger W. A. LeGassie, Planning and Analysis; and Dr. James Liverman, Environment and Safety. (LMT)« less

California Supreme Court refuses to hear PG and E appeal

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

Not Available

The California Supreme Court's refusal to hear an appeal to overturn the state commission's ruling is a victory for independent power producers and a defeat for Pacific Gas and Electric's effort to eliminate competition. At issue were decisions that the utility must stand by its agreement to buy power from independent producers under contract. The decision clarifies legal issues and removes the uncertainties which have hampered other projects.

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

PubMed

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

2018-06-01

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

Binaural hearing with electrical stimulation.

PubMed

Kan, Alan; Litovsky, Ruth Y

2015-04-01

Bilateral cochlear implantation is becoming a standard of care in many clinics. While much benefit has been shown through bilateral implantation, patients who have bilateral cochlear implants (CIs) still do not perform as well as normal hearing listeners in sound localization and understanding speech in noisy environments. This difference in performance can arise from a number of different factors, including the areas of hardware and engineering, surgical precision and pathology of the auditory system in deaf persons. While surgical precision and individual pathology are factors that are beyond careful control, improvements can be made in the areas of clinical practice and the engineering of binaural speech processors. These improvements should be grounded in a good understanding of the sensitivities of bilateral CI patients to the acoustic binaural cues that are important to normal hearing listeners for sound localization and speech in noise understanding. To this end, we review the current state-of-the-art in the understanding of the sensitivities of bilateral CI patients to binaural cues in electric hearing, and highlight the important issues and challenges as they relate to clinical practice and the development of new binaural processing strategies. This article is part of a Special Issue entitled . Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of headset, flight workload, hearing ability, and communications message quality on pilot performance.

PubMed

Casto, Kristen L; Casali, John G

2013-06-01

This study was designed to determine the effects of hearing loss, aviation headset type, flight workload complexity, and communication signal quality on pilots' performance in an army rotary-wing flight simulator. To maintain flight status, army aviators who do not meet current audiometric standards require a hearing loss waiver, which is based on speech intelligibility in quiet conditions. Because hearing loss characteristics of hearing-impaired aviators can vary greatly, and because performance is likely also influenced by degree of flight workload and communication demand, it was expected that performance among hearing-impaired aviators would also vary. Participants were 20 army helicopter pilots. Pilots flew three flights in a full motion-based helicopter simulator,with a different headset configuration and varying flight workload levels and communication signal quality characterizing each flight. Objective flight performance parameters of heading, altitude, and airspeed deviation and air traffic control command read-backs were measured. Statistically significant results suggest that high levels of flight workload, especially in combination with poor communications signal quality, lead to deficits in flight performance and speech intelligibility. These results support a conclusion that factors other than hearing thresholds and speech intelligibility in quiet should be considered when evaluating helicopter pilots' flight safety. The results also support a recommendation that hearing-impaired pilots use assistive communication technology and not fly with strictly passive headsets. The combined effects of flight environment with individual hearing levels should be considered when making recommendations concerning continued aviation flight status and those concerning communications headsets used in high-noise cockpits.

Didactic Content and Experiential Aging Simulation for Developing Patient-Centered Strategies and Empathy for Older Adults.

PubMed

Johnson, Carole E; Jilla, Anna Marie; Danhauer, Jeffrey L

2018-02-01

The number of people over 65 years of age is increasing, and many of those individuals will have sensorineural hearing loss in addition to other chronic health conditions. Future hearing health care providers need to be sensitive to the needs of elderly patients. The purpose of this article is to describe an experiential learning curriculum used in the Doctor of Audiology program in the Department of Communication Sciences and Disorders at the University of Oklahoma Health Sciences Center. The curriculum uses simulations of sensory disorders common in the elderly to transform knowledge and active experience into patient-centered, empathetic counseling skills and strategies to use with older adults with hearing loss.

Use of Baby Isao Simulator and Standardized Parents in Hearing Screening and Parent Counseling Education.

PubMed

Alanazi, Ahmad A; Nicholson, Nannette; Atcherson, Samuel R; Franklin, Clifford; Anders, Michael; Nagaraj, Naveen; Franklin, Jennifer; Highley, Patricia

2016-09-01

The primary purpose of this study was to test the effect of the combined use of trained standardized parents and a baby simulator on students' hearing screening and parental counseling knowledge and skills. A one-group pretest-posttest quasi-experimental study design was used to assess self-ratings of confidence in knowledge and skills and satisfaction of the educational experience with standardized parents and a baby simulator. The mean age of the 14 audiology students participating in this study was 24.79 years (SD = 1.58). Participants completed a pre- and postevent questionnaire in which they rated their level of confidence for specific knowledge and skills. Six students (2 students in each scenario) volunteered to participate in the infant hearing screening and counseling scenarios, whereas others participated as observers. All participants participated in the briefing and debriefing sessions immediately before and after each of 3 scenarios. After the last scenario, participants were asked to complete a satisfaction survey of their learning experience using simulation and standardized parents. Overall, the pre- and post-simulation event questionnaire revealed a significant improvement in the participants' self-rated confidence levels regarding knowledge and skills. The mean difference between pre- and postevent scores was 0.52 (p < .01). The mean satisfaction level was 4.71 (range = 3.91-5.00; SD = 0.30) based on a Likert scale, where 1 = not satisfied and 5 = very satisfied. The results of this novel educational activity demonstrate the value of using infant hearing screening and parental counseling simulation sessions to enhance student learning. In addition, this study demonstrates the use of simulation and standardized parents as an important pedagogical tool for audiology students. Students experienced a high level of satisfaction with the learning experience.

Effect of simulated bilateral cochlear distortion on speech discrimination in normal subjects.

PubMed

Hood, J D; Prasher, D K

1990-01-01

Bilateral sensorineural hearing loss may introduce grossly dissimilar cochlear distortion at the two ears, causing abnormal demands to be made upon the cortical analytical centres which normally receive congruent information. As a result, the prescription of binaural hearing aids may be a handicap rather than a help. In order to explore this possibility, 10 normal subjects were presented with simulated, dissimilar cochlear distortion at the two ears. Discrimination scores with binaural presentation were poorer than the best monaural score and there were clear indications that in the former, subjects selectively attended to one ear and neglected the other. In contrast, binaural presentation of the same simulated distortion resulted in a significant improvement, compared with the monaural discrimination score. Inability of the cortex to contend with discongruent speech input from the two ears may be a factor contributing to the rejection of binaural hearing aids in some individuals.

Community health worker training for infant hearing health: effectiveness of distance learning.

PubMed

Araújo, Eliene Silva; de Freitas Alvarenga, Kátia; Urnau, Daniele; Pagnossin, Débora Frizzo; Wen, Chao Lung

2013-09-01

The purpose of this study was to evaluate the effectiveness of a distance training program in infant hearing health to community health workers (CHWs). Pre- and post- tests were administered to two groups of subjects following the use of an interactive CD-ROM for tele-educational training. Two groups of subjects were used: Group I (GI) consisted of 43 CHWs who had previously participated in at least one training activity involving hearing health, and Group II (GII) were 47 CHWs who had received no prior training in hearing health. CHWs retained a significant amount of training content. There was not significant correlation between the global post-training questionnaire score and performance on the simulation activity (GI: r = 0.11, p = 0.698 and GII: r = 0.29, p = 0.074), and the simulation activity performance was significantly better among GI CHWs (p = 0.05). The CHWs' training in infant hearing health using an interactive tele-educational tool was effective, as the CHW demonstrated significant short-term information retention and applied such data in hypothetical situations representative of their daily activities.

Two-port network analysis and modeling of a balanced armature receiver.

PubMed

Kim, Noori; Allen, Jont B

2013-07-01

Models for acoustic transducers, such as loudspeakers, mastoid bone-drivers, hearing-aid receivers, etc., are critical elements in many acoustic applications. Acoustic transducers employ two-port models to convert between acoustic and electromagnetic signals. This study analyzes a widely-used commercial hearing-aid receiver ED series, manufactured by Knowles Electronics, Inc. Electromagnetic transducer modeling must consider two key elements: a semi-inductor and a gyrator. The semi-inductor accounts for electromagnetic eddy-currents, the 'skin effect' of a conductor (Vanderkooy, 1989), while the gyrator (McMillan, 1946; Tellegen, 1948) accounts for the anti-reciprocity characteristic [Lenz's law (Hunt, 1954, p. 113)]. Aside from Hunt (1954), no publications we know of have included the gyrator element in their electromagnetic transducer models. The most prevalent method of transducer modeling evokes the mobility method, an ideal transformer instead of a gyrator followed by the dual of the mechanical circuit (Beranek, 1954). The mobility approach greatly complicates the analysis. The present study proposes a novel, simplified and rigorous receiver model. Hunt's two-port parameters, the electrical impedance Ze(s), acoustic impedance Za(s) and electro-acoustic transduction coefficient Ta(s), are calculated using ABCD and impedance matrix methods (Van Valkenburg, 1964). The results from electrical input impedance measurements Zin(s), which vary with given acoustical loads, are used in the calculation (Weece and Allen, 2010). The hearing-aid receiver transducer model is designed based on energy transformation flow [electric→ mechanic→ acoustic]. The model has been verified with electrical input impedance, diaphragm velocity in vacuo, and output pressure measurements. This receiver model is suitable for designing most electromagnetic transducers and it can ultimately improve the design of hearing-aid devices by providing a simplified yet accurate, physically motivated analysis. This article is part of a special issue entitled "MEMRO 2012". Published by Elsevier B.V.

Molecular dynamics simulations of salicylate effects on the micro- and mesoscopic properties of a dipalmitoylphosphatidylcholine bilayer†

PubMed Central

Song, Yuhua; Guallar, Victor; Baker, Nathan A.

2008-01-01

Salicylate, an amphiphilic molecule and a popular member of non-steroidal antiinflammatory drug family, is known to affect hearing through reduction of the electromechanical coupling in the outer hair cells of the ear. This reduction of electromotility by salicylate has been widely studied but the molecular mechanism of the phenomenon is still unknown. In this study, we investigated one aspect of salicylate’s action; namely, the perturbation of electrical and mechanical membrane properties by salicylate in the absence of cytoskeletal or membrane-bound motor proteins such as prestin. In particular, we simulated the interaction of salicylate with a dipalmitoylphosphatidylcholine (DPPC) bilayer via atomically-detailed molecular dynamics simulations to observe the effect of salicylate on the microscopic and mesoscopic properties of the bilayer. The results demonstrate that salicylate interacts with the bilayer by associating at the water-DPPC interface in a nearly perpendicular orientation and penetrating more deeply into the bilayer than either sodium or chloride. This association has several affects on the membrane properties. First, binding of salicylate to the membrane displaces chloride from the bilayer-water interface. Second, salicylate influences the electrostatic potential and dielectric properties of the bilayer, with significant changes at the water-lipid bilayer interface. Third, salicylate association results in structural changes including decreased head group area per lipid and increased lipid tail order. However, salicylate does not significantly alter the mechanical properties of the DPPC bilayer; bulk compressibility, area compressibility, and bending modulus were only perturbed by small, statistically-insignificant amounts, by the presence of salicylate. The observations from these simulations are in qualitative agreement with experimental data and support the conclusion that salicylate influences the electrical but not the mechanical properties of DPPC membranes. PMID:16216066

Evaluation of Extended-wear Hearing Aid Technology for Operational Military Use

DTIC Science & Technology

2015-07-01

AFRL), Battlespace Acoustics Branch has been updated and approved to include the Lyric device. The AFRL protocol was sent to the Human Research...Jackson Foundation for the Advancement of Military Medicine Battlespace Acoustics Branch AFRL Wright-Patterson AFB, OH 45433 elizabeth_anne.mckenna.1...just after Hearing Aid 10 Drive speaker Incased in Foam 11 3.0 MEASUREMENTS PERFORMED 3.1 RE102 - Radiated Emissions, Electric Field, 2 MHz to 18

The effects of musical and linguistic components in recognition of real-world musical excerpts by cochlear implant recipients and normal-hearing adults.

PubMed

Gfeller, Kate; Jiang, Dingfeng; Oleson, Jacob J; Driscoll, Virginia; Olszewski, Carol; Knutson, John F; Turner, Christopher; Gantz, Bruce

2012-01-01

Cochlear implants (CI) are effective in transmitting salient features of speech, especially in quiet, but current CI technology is not well suited in transmission of key musical structures (e.g., melody, timbre). It is possible, however, that sung lyrics, which are commonly heard in real-world music may provide acoustical cues that support better music perception. The purpose of this study was to examine how accurately adults who use CIs (n = 87) and those with normal hearing (NH) (n = 17) are able to recognize real-world music excerpts based upon musical and linguistic (lyrics) cues. CI recipients were significantly less accurate than NH listeners on recognition of real-world music with or, in particular, without lyrics; however, CI recipients whose devices transmitted acoustic plus electric stimulation were more accurate than CI recipients reliant upon electric stimulation alone (particularly items without linguistic cues). Recognition by CI recipients improved as a function of linguistic cues. Participants were tested on melody recognition of complex melodies (pop, country, & classical styles). Results were analyzed as a function of: hearing status and history, device type (electric only or acoustic plus electric stimulation), musical style, linguistic and musical cues, speech perception scores, cognitive processing, music background, age, and in relation to self-report on listening acuity and enjoyment. Age at time of testing was negatively correlated with recognition performance. These results have practical implications regarding successful participation of CI users in music-based activities that include recognition and accurate perception of real-world songs (e.g., reminiscence, lyric analysis, & listening for enjoyment).

Hearing preservation cochlear implantation in children: The HEARRING Group consensus and practice guide.

PubMed

Rajan, Gunesh; Tavora-Vieira, Dayse; Baumgartner, Wolf-Dieter; Godey, Benoit; Müller, Joachim; O'Driscoll, Martin; Skarzynski, Henryk; Skarzynski, Piotr; Usami, Shin-Ichi; Adunka, Oliver; Agrawal, Sumit; Bruce, Iain; De Bodt, Marc; Caversaccio, Marco; Pilsbury, Harold; Gavilán, Javier; Hagen, Rudolf; Hagr, Abdulrahman; Kameswaran, Mohan; Karltorp, Eva; Kompis, Martin; Kuzovkov, Vlad; Lassaletta, Luis; Yongxin, Li; Lorens, Artur; Manoj, Manikoth; Martin, Jane; Mertens, Griet; Mlynski, Robert; Parnes, Lorne; Pulibalathingal, Sasidharan; Radeloff, Andreas; Raine, Christopher H; Rajeswaran, Ranjith; Schmutzhard, Joachim; Sprinzl, Georg; Staecker, Hinrich; Stephan, Kurt; Sugarova, Serafima; Zernotti, Mario; Zorowka, Patrick; Van de Heyning, Paul

2018-01-01

To provide multidisciplinary cochlear implant teams with a current consensus statement to support hearing preservation cochlear implantation (HPCI) in children, including those children with symptomatic partial deafness (PD) where the intention is to use electric-acoustic stimulation (EAS). The main objectives are to provide guidelines on who is a candidate, how to assess these children and when to implant if Med-El Flex electrode arrays are chosen for implantation. The HEARRING group reviewed the current evidence and practice regarding the management of children to be considered for HPCI surgery emphasizing the assessment needed prior to implantation in order to demonstrate the benefits in these children over time. The consensus statement addresses following three key questions: (1) Should these children be treated? (2) How to identify these children? (3) How to manage these children? The HEARRING group concludes that irrespective of the degree of residual hearing present, the concepts of hearing and structure preservation should be applied in every child undergoing cochlear implantation and that HPCI is a safe and reliable treatment option. Early detection and multidisciplinary assessment are key to the identification of children with symptomatic PD, these children should undergo HPCI as early as possible.

Information Theoretic Evaluation of a Noiseband-Based Cochlear Implant Simulator

PubMed Central

Aguiar, Daniel E.; Taylor, N. Ellen; Li, Jing; Gazanfari, Daniel K.; Talavage, Thomas M.; Laflen, J. Brandon; Neuberger, Heidi; Svirsky, Mario A.

2015-01-01

Noise-band vocoders are often used to simulate the signal processing algorithms used in cochlear implants (CIs), producing acoustic stimuli that may be presented to normal hearing (NH) subjects. Such evaluations may obviate the heterogeneity of CI user populations, achieving greater experimental control than when testing on CI subjects. However, it remains an open question whether advancements in algorithms developed on NH subjects using a simulator will necessarily improve performance in CI users. This study assessed the similarity in vowel identification of CI subjects and NH subjects using an 8-channel noise-band vocoder simulator configured to match input and output frequencies or to mimic output after a basalward shift of input frequencies. Under each stimulus condition, NH subjects performed the task both with and without feedback/training. Similarity of NH subjects to CI users was evaluated using correct identification rates and information theoretic approaches. Feedback/training produced higher rates of correct identification, as expected, but also resulted in error patterns that were closer to those of the CI users. Further evaluation remains necessary to determine how patterns of confusion at the token level are affected by the various parameters in CI simulators, providing insight into how a true CI simulation may be developed to facilitate more rapid prototyping and testing of novel CI signal processing and electrical stimulation strategies. PMID:26409068

Department of Labor Semiannual Regulatory Agenda

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-20

... flavoring. Diacetyl and a number of other volatile organic compounds are used to manufacture artificial... Institute of Electrical and Electronics Engineers consensus standard. Additionally, a public hearing was...

Magnetohydrodynamics and the National Coal Science, Technology, and Engineering Development Acts

NASA Astrophysics Data System (ADS)

The organization of a national coal science program and the production of electricity from coal using magnetohydrodynamic processes were the topics of a hearing before the subcommittee on energy research and development. The analysis of commercial energy at electric power plants, with an emphasis on the protection of the environment, were the main issues discussed.

Combined electric and acoustic hearing performance with Zebra® speech processor: speech reception, place, and temporal coding evaluation.

PubMed

Vaerenberg, Bart; Péan, Vincent; Lesbros, Guillaume; De Ceulaer, Geert; Schauwers, Karen; Daemers, Kristin; Gnansia, Dan; Govaerts, Paul J

2013-06-01

To assess the auditory performance of Digisonic(®) cochlear implant users with electric stimulation (ES) and electro-acoustic stimulation (EAS) with special attention to the processing of low-frequency temporal fine structure. Six patients implanted with a Digisonic(®) SP implant and showing low-frequency residual hearing were fitted with the Zebra(®) speech processor providing both electric and acoustic stimulation. Assessment consisted of monosyllabic speech identification tests in quiet and in noise at different presentation levels, and a pitch discrimination task using harmonic and disharmonic intonating complex sounds ( Vaerenberg et al., 2011 ). These tests investigate place and time coding through pitch discrimination. All tasks were performed with ES only and with EAS. Speech results in noise showed significant improvement with EAS when compared to ES. Whereas EAS did not yield better results in the harmonic intonation test, the improvements in the disharmonic intonation test were remarkable, suggesting better coding of pitch cues requiring phase locking. These results suggest that patients with residual hearing in the low-frequency range still have good phase-locking capacities, allowing them to process fine temporal information. ES relies mainly on place coding but provides poor low-frequency temporal coding, whereas EAS also provides temporal coding in the low-frequency range. Patients with residual phase-locking capacities can make use of these cues.

78 FR 44281 - Semiannual Agenda of Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-23

... Institute of Electrical and Electronics Engineers consensus standard. Additionally, a public hearing was... artificial butter flavoring. Diacetyl and a number of other volatile organic compounds are used to...

Evaluation of Noise Exposure Secondary to Wind Noise in Cyclists.

PubMed

Seidman, Michael D; Wertz, Anna G; Smith, Matthew M; Jacob, Steve; Ahsan, Syed F

2017-11-01

Objective Determine if the noise levels of wind exposure experienced by cyclists reach levels that could contribute to noise-induced hearing loss. Study Design Industrial lab research. Setting Industrial wind tunnel. Subjects and Methods A commercial-grade electric wind tunnel was used to simulate different speeds encountered by a cyclist. A single cyclist was used during the simulation for audiometric measurements. Microphones attached near the ears of the cyclist were used to measure the sound (dB sound pressure level) experienced by the cyclist. Loudness levels were measured with the head positioned at 15-degree increments from 0 degrees to 180 degrees relative to the oncoming wind at different speeds (10-60 mph). Results Wind noise ranged from 84.9 dB at 10 mph and increased proportionally with speed to a maximum of 120.3 dB at 60 mph. The maximum of 120.3 dB was measured at the downwind ear when the ear was 90 degrees away from the wind. Conclusions Wind noise experienced by a cyclist is proportional to the speed and the directionality of the wind current. Turbulent air flow patterns are observed that contribute to increased sound exposure in the downwind ear. Consideration of ear deflection equipment without compromising sound awareness for cyclists during prolonged rides is advised to avoid potential noise trauma. Future research is warranted and can include long-term studies including dosimetry measures of the sound and yearly pre- and postexposure audiograms of cyclists to detect if any hearing loss occurs with long-term cycling.

Validation of a Cochlear Implant Patient-Specific Model of the Voltage Distribution in a Clinical Setting

PubMed Central

Nogueira, Waldo; Schurzig, Daniel; Büchner, Andreas; Penninger, Richard T.; Würfel, Waldemar

2016-01-01

Cochlear Implants (CIs) are medical implantable devices that can restore the sense of hearing in people with profound hearing loss. Clinical trials assessing speech intelligibility in CI users have found large intersubject variability. One possibility to explain the variability is the individual differences in the interface created between electrodes of the CI and the auditory nerve. In order to understand the variability, models of the voltage distribution of the electrically stimulated cochlea may be useful. With this purpose in mind, we developed a parametric model that can be adapted to each CI user based on landmarks from individual cone beam computed tomography (CBCT) scans of the cochlea before and after implantation. The conductivity values of each cochlea compartment as well as the weighting factors of different grounding modes have also been parameterized. Simulations were performed modeling the cochlea and electrode positions of 12 CI users. Three models were compared with different levels of detail: a homogeneous model (HM), a non-patient-specific model (NPSM), and a patient-specific model (PSM). The model simulations were compared with voltage distribution measurements obtained from the backward telemetry of the 12 CI users. Results show that the PSM produces the lowest error when predicting individual voltage distributions. Given a patient-specific geometry and electrode positions, we show an example on how to optimize the parameters of the model and how to couple it to an auditory nerve model. The model here presented may help to understand speech performance variability and support the development of new sound coding strategies for CIs. PMID:27933290

78 FR 1598 - Semiannual Agenda of Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-08

... Institute of Electrical and Electronics Engineers consensus standard. Additionally, a public hearing was... in artificial butter flavoring. Diacetyl and a number of other volatile organic compounds are used to...

77 FR 7974 - Semiannual Agenda of Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-13

... Institute of Electrical and Electronics Engineers consensus standard. Additionally, a public hearing was... diacetyl, a major component in artificial butter flavoring. Diacetyl and a number of other volatile organic...

Mastication noise reduction method for fully implantable hearing aid using piezo-electric sensor.

PubMed

Na, Sung Dae; Lee, Gihyoun; Wei, Qun; Seong, Ki Woong; Cho, Jin Ho; Kim, Myoung Nam

2017-07-20

Fully implantable hearing devices (FIHDs) can be affected by generated biomechanical noise such as mastication noise. To reduce the mastication noise using a piezo-electric sensor, the mastication noise is measured with the piezo-electric sensor, and noise reduction is practiced by the energy difference. For the experiment on mastication noise, a skull model was designed using artificial skull model and a piezo-electric sensor that can measure the vibration signals better than other sensors. A 1 kHz pure-tone sound through a standard speaker was applied to the model while the lower jawbone of the model was moved in a masticatory fashion. The correlation coefficients and signal-to-noise ratio (SNR) before and after application of the proposed method were compared. It was found that the signal-to-noise ratio and correlation coefficients increased by 4.48 dB and 0.45, respectively. The mastication noise is measured by piezo-electric sensor as the mastication noise that occurred during vibration. In addition, the noise was reduced by using the proposed method in conjunction with MATLAB. In order to confirm the performance of the proposed method, the correlation coefficients and signal-to-noise ratio before and after signal processing were calculated. In the future, an implantable microphone for real-time processing will be developed.

Virtual acoustic environments for comprehensive evaluation of model-based hearing devices.

PubMed

Grimm, Giso; Luberadzka, Joanna; Hohmann, Volker

2018-06-01

Create virtual acoustic environments (VAEs) with interactive dynamic rendering for applications in audiology. A toolbox for creation and rendering of dynamic virtual acoustic environments (TASCAR) that allows direct user interaction was developed for application in hearing aid research and audiology. The software architecture and the simulation methods used to produce VAEs are outlined. Example environments are described and analysed. With the proposed software, a tool for simulation of VAEs is available. A set of VAEs rendered with the proposed software was described.

A Method for Assessing Auditory Spatial Analysis in Reverberant Multitalker Environments.

PubMed

Weller, Tobias; Best, Virginia; Buchholz, Jörg M; Young, Taegan

2016-07-01

Deficits in spatial hearing can have a negative impact on listeners' ability to orient in their environment and follow conversations in noisy backgrounds and may exacerbate the experience of hearing loss as a handicap. However, there are no good tools available for reliably capturing the spatial hearing abilities of listeners in complex acoustic environments containing multiple sounds of interest. The purpose of this study was to explore a new method to measure auditory spatial analysis in a reverberant multitalker scenario. This study was a descriptive case control study. Ten listeners with normal hearing (NH) aged 20-31 yr and 16 listeners with hearing impairment (HI) aged 52-85 yr participated in the study. The latter group had symmetrical sensorineural hearing losses with a four-frequency average hearing loss of 29.7 dB HL. A large reverberant room was simulated using a loudspeaker array in an anechoic chamber. In this simulated room, 96 scenes comprising between one and six concurrent talkers at different locations were generated. Listeners were presented with 45-sec samples of each scene, and were required to count, locate, and identify the gender of all talkers, using a graphical user interface on an iPad. Performance was evaluated in terms of correctly counting the sources and accuracy in localizing their direction. Listeners with NH were able to reliably analyze scenes with up to four simultaneous talkers, while most listeners with hearing loss demonstrated errors even with two talkers at a time. Localization performance decreased in both groups with increasing number of talkers and was significantly poorer in listeners with HI. Overall performance was significantly correlated with hearing loss. This new method appears to be useful for estimating spatial abilities in realistic multitalker scenes. The method is sensitive to the number of sources in the scene, and to effects of sensorineural hearing loss. Further work will be needed to compare this method to more traditional single-source localization tests. American Academy of Audiology.

[Simulation of speech perception with cochlear implants : Influence of frequency and level of fundamental frequency components with electronic acoustic stimulation].

PubMed

Rader, T; Fastl, H; Baumann, U

2017-03-01

After implantation of cochlear implants with hearing preservation for combined electronic acoustic stimulation (EAS), the residual acoustic hearing ability relays fundamental speech frequency information in the low frequency range. With the help of acoustic simulation of EAS hearing perception the impact of frequency and level fine structure of speech signals can be systematically examined. The aim of this study was to measure the speech reception threshold (SRT) under various noise conditions with acoustic EAS simulation by variation of the frequency and level information of the fundamental frequency f0 of speech. The study was carried out to determine to what extent the SRT is impaired by modification of the f0 fine structure. Using partial tone time pattern analysis an acoustic EAS simulation of the speech material from the Oldenburg sentence test (OLSA) was generated. In addition, determination of the f0 curve of the speech material was conducted. Subsequently, either the parameter frequency or level of f0 was fixed in order to remove one of the two fine contour information of the speech signal. The processed OLSA sentences were used to determine the SRT in background noise under various test conditions. The conditions "f0 fixed frequency" and "f0 fixed level" were tested under two different situations, under "amplitude modulated background noise" and "continuous background noise" conditions. A total of 24 subjects with normal hearing participated in the study. The SRT in background noise for the condition "f0 fixed frequency" was more favorable in continuous noise with 2.7 dB and in modulated noise with 0.8 dB compared to the condition "f0 fixed level" with 3.7 dB and 2.9 dB, respectively. In the simulation of speech perception with cochlear implants and acoustic components, the level information of the fundamental frequency had a stronger impact on speech intelligibility than the frequency information. The method of simulation of transmission of cochlear implants allows investigation of how various parameters influence speech intelligibility in subjects with normal hearing.

Cochlear implant – state of the art

PubMed Central

Lenarz, Thomas

2018-01-01

Cochlear implants are the treatment of choice for auditory rehabilitation of patients with sensory deafness. They restore the missing function of inner hair cells by transforming the acoustic signal into electrical stimuli for activation of auditory nerve fibers. Due to the very fast technology development, cochlear implants provide open-set speech understanding in the majority of patients including the use of the telephone. Children can achieve a near to normal speech and language development provided their deafness is detected early after onset and implantation is performed quickly thereafter. The diagnostic procedure as well as the surgical technique have been standardized and can be adapted to the individual anatomical and physiological needs both in children and adults. Special cases such as cochlear obliteration might require special measures and re-implantation, which can be done in most cases in a straight forward way. Technology upgrades count for better performance. Future developments will focus on better electrode-nerve interfaces by improving electrode technology. An increased number of electrical contacts as well as the biological treatment with regeneration of the dendrites growing onto the electrode will increase the number of electrical channels. This will give room for improved speech coding strategies in order to create the bionic ear, i.e. to restore the process of natural hearing by means of technology. The robot-assisted surgery will allow for high precision surgery and reliable hearing preservation. Biological therapies will support the bionic ear. Methods are bio-hybrid electrodes, which are coded by stem cells transplanted into the inner ear to enhance auto-production of neurotrophins. Local drug delivery will focus on suppression of trauma reaction and local regeneration. Gene therapy by nanoparticles will hopefully lead to the preservation of residual hearing in patients being affected by genetic hearing loss. Overall the cochlear implant is a very powerful tool to rehabilitate patients with sensory deafness. More than 1 million of candidates in Germany today could benefit from this high technology auditory implant. Only 50,000 are implanted so far. In the future, the procedure can be done under local anesthesia, will be minimally invasive and straight forward. Hearing preservation will be routine. PMID:29503669

Properties of an adaptive feedback equalization algorithm.

PubMed

Engebretson, A M; French-St George, M

1993-01-01

This paper describes a new approach to feedback equalization for hearing aids. The method involves the use of an adaptive algorithm that estimates and tracks the characteristic of the hearing aid feedback path. The algorithm is described and the results of simulation studies and bench testing are presented.

The Effects of Musical and Linguistic Components in Recognition of Real-World Musical Excerpts by Cochlear Implant Recipients and Normal-Hearing Adults

PubMed Central

Gfeller, Kate; Jiang, Dingfeng; Oleson, Jacob; Driscoll, Virginia; Olszewski, Carol; Knutson, John F.; Turner, Christopher; Gantz, Bruce

2011-01-01

Background Cochlear implants (CI) are effective in transmitting salient features of speech, especially in quiet, but current CI technology is not well suited in transmission of key musical structures (e.g., melody, timbre). It is possible, however, that sung lyrics, which are commonly heard in real-world music may provide acoustical cues that support better music perception. Objective The purpose of this study was to examine how accurately adults who use CIs (n=87) and those with normal hearing (NH) (n=17) are able to recognize real-world music excerpts based upon musical and linguistic (lyrics) cues. Results CI recipients were significantly less accurate than NH listeners on recognition of real-world music with or, in particular, without lyrics; however, CI recipients whose devices transmitted acoustic plus electric stimulation were more accurate than CI recipients reliant upon electric stimulation alone (particularly items without linguistic cues). Recognition by CI recipients improved as a function of linguistic cues. Methods Participants were tested on melody recognition of complex melodies (pop, country, classical styles). Results were analyzed as a function of: hearing status and history, device type (electric only or acoustic plus electric stimulation), musical style, linguistic and musical cues, speech perception scores, cognitive processing, music background, age, and in relation to self-report on listening acuity and enjoyment. Age at time of testing was negatively correlated with recognition performance. Conclusions These results have practical implications regarding successful participation of CI users in music-based activities that include recognition and accurate perception of real-world songs (e.g., reminiscence, lyric analysis, listening for enjoyment). PMID:22803258

Stability of low-frequency residual hearing in patients who are candidates for combined acoustic plus electric hearing.

PubMed

Yao, Wai Na; Turner, Christopher W; Gantz, Bruce J

2006-10-01

The purpose of this study was to investigate the stability over time of low-frequency auditory thresholds to better determine if the new technique of using a short-electrode cochlear implant that preserves residual low-frequency acoustic hearing can be a long-term solution for those with severe-to-profound hearing loss at high frequencies. The present study determined the long-term rate of decline in acoustic hearing in patients who have a preexisting hearing loss yet have not been implanted with a cochlear implant. A retrospective analysis of patients' audiograms that fit into the range for candidacy for the short-electrode device was performed to calculate the rate of change of threshold over time. The analysis of adult patients' data indicated that there was an average of only 1.05 dB hearing deterioration per year in the low frequencies and that presbycusis accounted for approximately one third to one half of this decline. The average deterioration of hearing threshold for pediatric patients was 1.2 dB per year; however, the rates of change in pediatric patients were considerably more variable (across individuals and across frequencies) than in adults. These data provide support for the idea that the short-electrode cochlear implant may be a practical solution for most adults in the long run, but this may not be the case for all pediatric patients.

Testing a Method for Quantifying the Output of Implantable Middle Ear Hearing Devices

PubMed Central

Rosowski, J.J.; Chien, W.; Ravicz, M.E.; Merchant, S.N.

2008-01-01

This report describes tests of a standard practice for quantifying the performance of implantable middle ear hearing devices (also known as implantable hearing aids). The standard and these tests were initiated by the Food and Drug Administration of the United States Government. The tests involved measurements on two hearing devices, one commercially available and the other home built, that were implanted into ears removed from human cadavers. The tests were conducted to investigate the utility of the practice and its outcome measures: the equivalent ear canal sound pressure transfer function that relates electrically driven middle ear velocities to the equivalent sound pressure needed to produce those velocities, and the maximum effective ear canal sound pressure. The practice calls for measurements in cadaveric ears in order to account for the varied anatomy and function of different human middle ears. PMID:17406105

The effect of compression speed on intelligibility: simulated hearing-aid processing with and without original temporal fine structure information.

PubMed

Hopkins, Kathryn; King, Andrew; Moore, Brian C J

2012-09-01

Hearing aids use amplitude compression to compensate for the effects of loudness recruitment. The compression speed that gives the best speech intelligibility varies among individuals. Moore [(2008). Trends Amplif. 12, 300-315] suggested that an individual's sensitivity to temporal fine structure (TFS) information may affect which compression speed gives most benefit. This hypothesis was tested using normal-hearing listeners with a simulated hearing loss. Sentences in a competing talker background were processed using multi-channel fast or slow compression followed by a simulation of threshold elevation and loudness recruitment. Signals were either tone vocoded with 1-ERB(N)-wide channels (where ERB(N) is the bandwidth of normal auditory filters) to remove the original TFS information, or not processed further. In a second experiment, signals were vocoded with either 1 - or 2-ERB(N)-wide channels, to test whether the available spectral detail affects the optimal compression speed. Intelligibility was significantly better for fast than slow compression regardless of vocoder channel bandwidth. The results suggest that the availability of original TFS or detailed spectral information does not affect the optimal compression speed. This conclusion is tentative, since while the vocoder processing removed the original TFS information, listeners may have used the altered TFS in the vocoded signals.

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

PubMed

Rader, Tobias; Fastl, Hugo; Baumann, Uwe

2013-01-01

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

[Evaluation of hazards caused by magnetic field emitted from magnetotherapy applicator to the users of bone conduction hearing prostheses].

PubMed

Zradziński, Patryk; Karpowicz, Jolanta; Gryz, Krzysztof; Leszko, Wiesław

2017-06-27

Low frequency magnetic field, inducing electrical field (E_in) inside conductive structures may directly affect the human body, e.g., by electrostimulation in the nervous system. In addition, the spatial distribution and level of E_in are disturbed in tissues neighbouring the medical implant. Numerical models of magneto-therapeutic applicator (emitting sinusoidal magnetic field of frequency 100 Hz) and the user of hearing implant (based on bone conduction: Bonebridge type - IS-BB or BAHA (bone anchorde hearing aid) type - IS-BAHA) were worked out. Values of E_in were analyzed in the model of the implant user's head, e.g., physiotherapist, placed next to the applicator. It was demonstrated that the use of IS-BB or IS-BAHA makes electromagnetic hazards significantly higher (up to 4-fold) compared to the person without implant exposed to magnetic field heterogeneous in space. Hazards for IS-BAHA users are higher than those for IS-BB users. It was found that applying the principles of directive 2013/35/EU, at exposure to magnetic field below exposure limits the direct biophysical effects of exposure in hearing prosthesis users may exceed relevant limits. Whereas applying principles and limits set up by Polish labor law or the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines, the compliance with the exposure limits also ensures the compliance with relevant limits of electric field induced in the body of hearing implant user. It is necessary to assess individually electromagnetic hazard concerning hearing implant users bearing in mind significantly higher hazards to them compared to person without implant or differences between levels of hazards faced by users of implants of various structural or technological solutions. Med Pr 2017;68(4):469-477. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Effects of reverberation and noise on speech intelligibility in normal-hearing and aided hearing-impaired listeners.

PubMed

Xia, Jing; Xu, Buye; Pentony, Shareka; Xu, Jingjing; Swaminathan, Jayaganesh

2018-03-01

Many hearing-aid wearers have difficulties understanding speech in reverberant noisy environments. This study evaluated the effects of reverberation and noise on speech recognition in normal-hearing listeners and hearing-impaired listeners wearing hearing aids. Sixteen typical acoustic scenes with different amounts of reverberation and various types of noise maskers were simulated using a loudspeaker array in an anechoic chamber. Results showed that, across all listening conditions, speech intelligibility of aided hearing-impaired listeners was poorer than normal-hearing counterparts. Once corrected for ceiling effects, the differences in the effects of reverberation on speech intelligibility between the two groups were much smaller. This suggests that, at least, part of the difference in susceptibility to reverberation between normal-hearing and hearing-impaired listeners was due to ceiling effects. Across both groups, a complex interaction between the noise characteristics and reverberation was observed on the speech intelligibility scores. Further fine-grained analyses of the perception of consonants showed that, for both listener groups, final consonants were more susceptible to reverberation than initial consonants. However, differences in the perception of specific consonant features were observed between the groups.

Delayed changes in auditory status in cochlear implant users with preserved acoustic hearing.

PubMed

Scheperle, Rachel A; Tejani, Viral D; Omtvedt, Julia K; Brown, Carolyn J; Abbas, Paul J; Hansen, Marlan R; Gantz, Bruce J; Oleson, Jacob J; Ozanne, Marie V

2017-07-01

This retrospective review explores delayed-onset hearing loss in 85 individuals receiving cochlear implants designed to preserve acoustic hearing at the University of Iowa Hospitals and Clinics between 2001 and 2015. Repeated measures of unaided behavioral audiometric thresholds, electrode impedance, and electrically evoked compound action potential (ECAP) amplitude growth functions were used to characterize longitudinal changes in auditory status. Participants were grouped into two primary categories according to changes in unaided behavioral thresholds: (1) stable hearing or symmetrical hearing loss and (2) delayed loss of hearing in the implanted ear. Thirty-eight percent of this sample presented with delayed-onset hearing loss of various degrees and rates of change. Neither array type nor insertion approach (round window or cochleostomy) had a significant effect on prevalence. Electrode impedance increased abruptly for many individuals exhibiting precipitous hearing loss; the increase was often transient. The impedance increases were significantly larger than the impedance changes observed for individuals with stable or symmetrical hearing loss. Moreover, the impedance changes were associated with changes in behavioral thresholds for individuals with a precipitous drop in behavioral thresholds. These findings suggest a change in the electrode environment coincident with the change in auditory status. Changes in ECAP thresholds, growth function slopes, and suprathreshold amplitudes were not correlated with changes in behavioral thresholds, suggesting that neural responsiveness in the region excited by the implant is relatively stable. Further exploration into etiology of delayed-onset hearing loss post implantation is needed, with particular interest in mechanisms associated with changes in the intracochlear environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Benefits of Localization and Speech Perception with Multiple Noise Sources in Listeners with a Short-electrode Cochlear Implant

PubMed Central

Dunn, Camille C.; Perreau, Ann; Gantz, Bruce; Tyler, Richard

2009-01-01

Background Research suggests that for individuals with significant low-frequency hearing, implantation of a short-electrode cochlear implant may provide benefits of improved speech perception abilities. Because this strategy combines acoustic and electrical hearing within the same ear while at the same time preserving low-frequency residual acoustic hearing in both ears, localization abilities may also be improved. However, very little research has focused on the localization and spatial hearing abilities of users with a short-electrode cochlear implant. Purpose The purpose of this study was to evaluate localization abilities for listeners with a short-electrode cochlear implant who continue to wear hearing aids in both ears. A secondary purpose was to document speech perception abilities using a speech in noise test with spatially-separate noise sources. Research Design Eleven subjects that utilized a short-electrode cochlear implant and bilateral hearing aids were tested on localization and speech perception with multiple noise locations using an eight-loudspeaker array. Performance was assessed across four listening conditions using various combinations of cochlear implant and/or hearing aid use. Results Results for localization showed no significant difference between using bilateral hearing aids and bilateral hearing aids plus the cochlear implant. However, there was a significant difference between the bilateral hearing aid condition and the implant plus use of a contralateral hearing aid for all eleven subjects. Results for speech perception showed a significant benefit when using bilateral hearing aids plus the cochlear implant over use of the implant plus only one hearing aid. Conclusion Combined use of both hearing aids and the cochlear implant show significant benefits for both localization and speech perception in noise for users with a short-electrode cochlear implant. These results emphasize the importance of low-frequency information in two ears for the purpose of localization and speech perception in noise. PMID:20085199

Benefits of localization and speech perception with multiple noise sources in listeners with a short-electrode cochlear implant.

PubMed

Dunn, Camille C; Perreau, Ann; Gantz, Bruce; Tyler, Richard S

2010-01-01

Research suggests that for individuals with significant low-frequency hearing, implantation of a short-electrode cochlear implant may provide benefits of improved speech perception abilities. Because this strategy combines acoustic and electrical hearing within the same ear while at the same time preserving low-frequency residual acoustic hearing in both ears, localization abilities may also be improved. However, very little research has focused on the localization and spatial hearing abilities of users with a short-electrode cochlear implant. The purpose of this study was to evaluate localization abilities for listeners with a short-electrode cochlear implant who continue to wear hearing aids in both ears. A secondary purpose was to document speech perception abilities using a speech-in-noise test with spatially separate noise sources. Eleven subjects that utilized a short-electrode cochlear implant and bilateral hearing aids were tested on localization and speech perception with multiple noise locations using an eight-loudspeaker array. Performance was assessed across four listening conditions using various combinations of cochlear implant and/or hearing aid use. Results for localization showed no significant difference between using bilateral hearing aids and bilateral hearing aids plus the cochlear implant. However, there was a significant difference between the bilateral hearing aid condition and the implant plus use of a contralateral hearing aid for all 11 subjects. Results for speech perception showed a significant benefit when using bilateral hearing aids plus the cochlear implant over use of the implant plus only one hearing aid. Combined use of both hearing aids and the cochlear implant show significant benefits for both localization and speech perception in noise for users with a short-electrode cochlear implant. These results emphasize the importance of low-frequency information in two ears for the purpose of localization and speech perception in noise.

The High Price of Noise Exposure

MedlinePlus

... Current Issue Past Issues Hearing Disorders The High Price of Noise Exposure Past Issues / Fall 2008 Table ... These tiny structures convert sound waves into electrical energy. Our auditory nerve sends this energy to the ...

What Are Some Types of Assistive Devices and How Are They Used?

MedlinePlus

... in persons with hearing problems. Cognitive assistance, including computer or electrical assistive devices, can help people function following brain injury. Computer software and hardware, such as voice recognition programs, ...

NIST System for Measuring the Directivity Index of Hearing Aids under Simulated Real-Ear Conditions.

PubMed

Wagner, Randall P

2013-01-01

The directivity index is a parameter that is commonly used to characterize the performance of directional hearing aids, and is determined from the measured directional response. Since this response is different for a hearing aid worn on a person as compared to when it is in a free field, directivity index measurements of hearing aids are usually done under simulated real-ear conditions. Details are provided regarding the NIST system for measuring the hearing aid directivity index under these conditions and how this system is used to implement a standardized procedure for performing such measurements. This procedure involves a sampling method that utilizes sound source locations distributed in a semi-aligned zone array on an imaginary spherical surface surrounding a standardized acoustical test manikin. The capabilities of the system were demonstrated over the frequency range of one-third-octave bands with center frequencies from 200 Hz to 8000 Hz through NIST participation in an interlaboratory comparison. This comparison was conducted between eight different laboratories of members of Working Group S3/WG48, Hearing Aids, established by Accredited Standards Committee S3, Bioacoustics, which is administered by the Acoustical Society of America and accredited by the American National Standards Institute. Directivity measurements were made for a total of six programmed memories in two different hearing aids and for the unaided manikin with the manikin right pinna accompanying the aids. Omnidirectional, cardioid, and bidirectional response patterns were measured. Results are presented comparing the NIST data with the reference values calculated from the data reported by all participating laboratories.

NIST System for Measuring the Directivity Index of Hearing Aids under Simulated Real-Ear Conditions

PubMed Central

Wagner, Randall P

2013-01-01

The directivity index is a parameter that is commonly used to characterize the performance of directional hearing aids, and is determined from the measured directional response. Since this response is different for a hearing aid worn on a person as compared to when it is in a free field, directivity index measurements of hearing aids are usually done under simulated real-ear conditions. Details are provided regarding the NIST system for measuring the hearing aid directivity index under these conditions and how this system is used to implement a standardized procedure for performing such measurements. This procedure involves a sampling method that utilizes sound source locations distributed in a semi-aligned zone array on an imaginary spherical surface surrounding a standardized acoustical test manikin. The capabilities of the system were demonstrated over the frequency range of one-third-octave bands with center frequencies from 200 Hz to 8000 Hz through NIST participation in an interlaboratory comparison. This comparison was conducted between eight different laboratories of members of Working Group S3/WG48, Hearing Aids, established by Accredited Standards Committee S3, Bioacoustics, which is administered by the Acoustical Society of America and accredited by the American National Standards Institute. Directivity measurements were made for a total of six programmed memories in two different hearing aids and for the unaided manikin with the manikin right pinna accompanying the aids. Omnidirectional, cardioid, and bidirectional response patterns were measured. Results are presented comparing the NIST data with the reference values calculated from the data reported by all participating laboratories. PMID:26401425

The use of fundamental frequency for lexical segmentation in listeners with cochlear implants.

PubMed

Spitzer, Stephanie; Liss, Julie; Spahr, Tony; Dorman, Michael; Lansford, Kaitlin

2009-06-01

Fundamental frequency (F0) variation is one of a number of acoustic cues normal hearing listeners use for guiding lexical segmentation of degraded speech. This study examined whether F0 contour facilitates lexical segmentation by listeners fitted with cochlear implants (CIs). Lexical boundary error patterns elicited under unaltered and flattened F0 conditions were compared across three groups: listeners with conventional CI, listeners with CI and preserved low-frequency acoustic hearing, and normal hearing listeners subjected to CI simulations. Results indicate that all groups attended to syllabic stress cues to guide lexical segmentation, and that F0 contours facilitated performance for listeners with low-frequency hearing.

Electric-acoustic interactions in the hearing cochlea: single fiber recordings.

PubMed

Tillein, J; Hartmann, R; Kral, A

2015-04-01

The present study investigates interactions of simultaneous electric and acoustic stimulation in single auditory nerve fibers in normal hearing cats. First, the auditory nerve was accessed with a microelectrode and response areas of single nerve fibers were determined for acoustic stimulation. Second, response thresholds to extracochlear sinusoidal electric stimulation using ball electrodes positioned at the round window were measured. Third, interactions that occurred with combined electric-acoustic stimulation were investigated in two areas: (1) the spectral domain (frequency response areas) and (2) the temporal domain (phase-locking to each stimulus) at moderate stimulus intensities (electric: 6 dB re threshold, acoustic: 20-40 dB re threshold at the characteristic frequency, CF). For fibers responding to both modalities responses to both electric and acoustic stimulation could be clearly identified. CFs, thresholds, and bandwidth (Q10dB) of acoustic responses were not significantly affected by simultaneous electric stimulation. Phase-locking of electric responses decreased in the presence of acoustic stimulation. Indication for electric stimulation of inner hair cells with 125 and 250 Hz were observed. However, these did not disturb the acoustic receptive fields of auditory nerve fibers. There was a trade-off between these responses when the intensities of the stimulation were varied: Relatively more intense stimulation dominated less intense stimulation. The scarcity of interaction between the different stimulus modalities demonstrates the ability of electric-acoustic stimulation to transfer useful information through both stimulation channels at the same time despite cochlear electrophonic effects. Application of 30 Hz electric stimulation resulted in a strong suppression of acoustic activity in the anodic phase of the stimulus. An electric stimulation like this might thus be used to control acoustic responses. This article is part of a Special Issue entitled . Copyright © 2014 Elsevier B.V. All rights reserved.

Impedance testing on cochlear implants after electroconvulsive therapy.

PubMed

McRackan, Theodore R; Rivas, Alejandro; Hedley-Williams, Andrea; Raj, Vidya; Dietrich, Mary S; Clark, Nathaniel K; Labadie, Robert F

2014-12-01

Cochlear implants (CI) are neural prostheses that restore hearing to individuals with profound sensorineural hearing loss. The surgically implanted component consists of an electrode array, which is threaded into the cochlea, and an electronic processor, which is buried under the skin behind the ear. The Food and Drug Administration and CI manufacturers contend that electroconvulsive therapy (ECT) is contraindicated in CI recipients owing to risk of damage to the implant and/or the patient. We hypothesized that ECT does no electrical damage to CIs. Ten functional CIs were implanted in 5 fresh cadaveric human heads. Each head then received a consecutive series of 12 unilateral ECT sessions applying maximum full pulse-width energy settings. Electroconvulsive therapy was delivered contralaterally to 5 CIs and ipsilaterally to 5 CIs. Electrical integrity testing (impedance testing) of the electrode array was performed before and after CI insertion, and after the first, third, fifth, seventh, ninth, and 12th ECT sessions. Electroconvulsive therapy was performed by a staff psychiatrist experienced with the technique. Explanted CIs were sent back to the manufacturer for further integrity testing. No electrical damage was identified during impedance testing. Overall, there were statistically significant decreases in impedances (consistent with no electrical damage) when comparing pre-ECT impedance values to those after 12 sessions. There was no statistically significant difference (P > 0.05) in impedance values comparing ipsilateral to contralateral ECT. Manufacturer testing revealed no other electrical damage to the CIs. Electroconvulsive therapy does not seem to cause any detectable electrical injury to CIs.

77 FR 66963 - Public Hearing and Opportunities for Public Review and Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-08

... generate electricity, increases the levels of nitrogen, oxygen, and other gases in the water, beyond state...' bills until the balance is completely billed. Part V--Proposed Oversupply Rate Schedules BPA's proposed...

Speech recognition for bilaterally asymmetric and symmetric hearing aid microphone modes in simulated classroom environments.

PubMed

Ricketts, Todd A; Picou, Erin M

2013-09-01

This study aimed to evaluate the potential utility of asymmetrical and symmetrical directional hearing aid fittings for school-age children in simulated classroom environments. This study also aimed to evaluate speech recognition performance of children with normal hearing in the same listening environments. Two groups of school-age children 11 to 17 years of age participated in this study. Twenty participants had normal hearing, and 29 participants had sensorineural hearing loss. Participants with hearing loss were fitted with behind-the-ear hearing aids with clinically appropriate venting and were tested in 3 hearing aid configurations: bilateral omnidirectional, bilateral directional, and asymmetrical directional microphones. Speech recognition testing was completed in each microphone configuration in 3 environments: Talker-Front, Talker-Back, and Question-Answer situations. During testing, the location of the speech signal changed, but participants were always seated in a noisy, moderately reverberant classroom-like room. For all conditions, results revealed expected effects of directional microphones on speech recognition performance. When the signal of interest was in front of the listener, bilateral directional microphone was best, and when the signal of interest was behind the listener, bilateral omnidirectional microphone was best. Performance with asymmetric directional microphones was between the 2 symmetrical conditions. The magnitudes of directional benefits and decrements were not significantly correlated. In comparison with their peers with normal hearing, children with hearing loss performed similarly to their peers with normal hearing when fitted with directional microphones and the speech was from the front. In contrast, children with normal hearing still outperformed children with hearing loss if the speech originated from behind, even when the children were fitted with the optimal hearing aid microphone mode for the situation. Bilateral directional microphones can be effective in improving speech recognition performance for children in the classroom, as long as child is facing the talker of interest. Bilateral directional microphones, however, can impair performance if the signal originates from behind a listener. However, these data suggest that the magnitude of decrement is not predictable from an individual's benefit. The results re-emphasize the importance of appropriate switching between microphone modes so children can take full advantage of directional benefits without being hurt by directional decrements. An asymmetric fitting limits decrements, but does not lead to maximum speech recognition scores when compared with the optimal symmetrical fitting. Therefore, the asymmetric mode may not be the best option as a default fitting for children in a classroom environment. While directional microphones improve performance for children with hearing loss, their performance in most conditions continues to be impaired relative to their normal-hearing peers, particularly when the signals of interest originate from behind or from an unpredictable location.

An Evaluation of Economists’ Influence on Electric Utility Rate Reforms,

DTIC Science & Technology

1982-01-01

PURPA ) of 1978 required all 50 state utility commissions and more than 150 other jurisdictions regulating electric utility rates to con- sider the...complex rate structure). The "cost effectiveness" language of PURPA suggests such an evaluation criterion based on long term considerations without...detailing the components of benefit; see Joskow. Individual hearings under PURPA have generally employed three standards: fuel or energy savings (if a TOU

On the stability and compressive nonlinearity of a physiologically based model of the cochlea

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

Nankali, Amir; Grosh, Karl; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan

Hearing relies on a series of coupled electrical, acoustical (fluidic) and mechanical interactions inside the cochlea that enable sound processing. A positive feedback mechanism within the cochlea, called the cochlear amplifier, provides amplitude and frequency selectivity in the mammalian auditory system. The cochlear amplifier and stability are studied using a nonlinear, micromechanical model of the Organ of Corti (OoC) coupled to the electrical potentials in the cochlear ducts. It is observed that the mechano-electrical transduction (MET) sensitivity and somatic motility of the outer hair cell (OHC), control the cochlear stability. Increasing MET sensitivity beyond a critical value, while electromechanical couplingmore » coefficient is within a specific range, causes instability. We show that instability in this model is generated through a supercritical Hopf bifurcation. A reduced order model of the system is approximated and it is shown that the tectorial membrane (TM) transverse mode effect on the dynamics is significant while the radial mode can be simplified from the equations. The cochlear amplifier in this model exhibits good agreement with the experimental data. A comprehensive 3-dimensional model based on the cross sectional model is simulated and the results are compared. It is indicated that the global model qualitatively inherits some characteristics of the local model, but the longitudinal coupling along the cochlea shifts the stability boundary (i.e., Hopf bifurcation point) and enhances stability.« less

On the electrophonic generation of audio frequency sound by meteors

NASA Astrophysics Data System (ADS)

Kelley, Michael C.; Price, Colin

2017-04-01

Recorded for centuries, people can hear and see meteors nearly concurrently. Electromagnetic energy clearly propagates at the speed of light and converts to sound (called electrophonics) when coupled to metals. An explanation for the electromagnetic energy source is suggested. Coma ions around the meteor head can easily travel across magnetic field lines up to 120 km. The electrons, however, are tied to magnetic field lines, since they must gyrate around the field above 75 km. A large ambipolar electric field must be generated to conserve charge neutrality. This localized electric field maps to the E region then drives a large Hall current that launches the electromagnetic wave. Using antenna theory and following, a power flux of over 10-8 W/m2 at the ground is found. Electrophonic conversion to sound efficiency then needs to be only 0.1% to explain why humans can hear and see meteors nearly concurrently.

SPAIDE: A Real-time Research Platform for the Clarion CII/90K Cochlear Implant

NASA Astrophysics Data System (ADS)

Van Immerseel, L.; Peeters, S.; Dykmans, P.; Vanpoucke, F.; Bracke, P.

2005-12-01

SPAIDE ( sound-processing algorithm integrated development environment) is a real-time platform of Advanced Bionics Corporation (Sylmar, Calif, USA) to facilitate advanced research on sound-processing and electrical-stimulation strategies with the Clarion CII and 90K implants. The platform is meant for testing in the laboratory. SPAIDE is conceptually based on a clear separation of the sound-processing and stimulation strategies, and, in specific, on the distinction between sound-processing and stimulation channels and electrode contacts. The development environment has a user-friendly interface to specify sound-processing and stimulation strategies, and includes the possibility to simulate the electrical stimulation. SPAIDE allows for real-time sound capturing from file or audio input on PC, sound processing and application of the stimulation strategy, and streaming the results to the implant. The platform is able to cover a broad range of research applications; from noise reduction and mimicking of normal hearing, over complex (simultaneous) stimulation strategies, to psychophysics. The hardware setup consists of a personal computer, an interface board, and a speech processor. The software is both expandable and to a great extent reusable in other applications.

Evaluation of Adaptive Noise Management Technologies for School-Age Children with Hearing Loss.

PubMed

Wolfe, Jace; Duke, Mila; Schafer, Erin; Jones, Christine; Rakita, Lori

2017-05-01

Children with hearing loss experience significant difficulty understanding speech in noisy and reverberant situations. Adaptive noise management technologies, such as fully adaptive directional microphones and digital noise reduction, have the potential to improve communication in noise for children with hearing aids. However, there are no published studies evaluating the potential benefits children receive from the use of adaptive noise management technologies in simulated real-world environments as well as in daily situations. The objective of this study was to compare speech recognition, speech intelligibility ratings (SIRs), and sound preferences of children using hearing aids equipped with and without adaptive noise management technologies. A single-group, repeated measures design was used to evaluate performance differences obtained in four simulated environments. In each simulated environment, participants were tested in a basic listening program with minimal noise management features, a manual program designed for that scene, and the hearing instruments' adaptive operating system that steered hearing instrument parameterization based on the characteristics of the environment. Twelve children with mild to moderately severe sensorineural hearing loss. Speech recognition and SIRs were evaluated in three hearing aid programs with and without noise management technologies across two different test sessions and various listening environments. Also, the participants' perceptual hearing performance in daily real-world listening situations with two of the hearing aid programs was evaluated during a four- to six-week field trial that took place between the two laboratory sessions. On average, the use of adaptive noise management technology improved sentence recognition in noise for speech presented in front of the participant but resulted in a decrement in performance for signals arriving from behind when the participant was facing forward. However, the improvement with adaptive noise management exceeded the decrement obtained when the signal arrived from behind. Most participants reported better subjective SIRs when using adaptive noise management technologies, particularly when the signal of interest arrived from in front of the listener. In addition, most participants reported a preference for the technology with an automatically switching, adaptive directional microphone and adaptive noise reduction in real-world listening situations when compared to conventional, omnidirectional microphone use with minimal noise reduction processing. Use of the adaptive noise management technologies evaluated in this study improves school-age children's speech recognition in noise for signals arriving from the front. Although a small decrement in speech recognition in noise was observed for signals arriving from behind the listener, most participants reported a preference for use of noise management technology both when the signal arrived from in front and from behind the child. The results of this study suggest that adaptive noise management technologies should be considered for use with school-age children when listening in academic and social situations. American Academy of Audiology

Reimplantation with a conventional length electrode following residual hearing loss in four hybrid implant recipients

PubMed Central

Carlson, Matthew L; Archibald, David J; Gifford, Rene H; Driscoll, Colin LW; Beatty, Charles W

2014-01-01

Hypothesis Revision surgery using a newer-generation conventional length cochlear implant electrode will provide improved speech perception in patients that initially underwent hybrid electrode implantation and experienced post-operative loss of residual hearing and performance deterioration. Clinical presentation We present four patients who experienced delayed post-operative hearing loss following implantation with the Nucleus Hybrid S8 device and underwent reimplantation with the Nucleus Freedom or Nucleus 5 device using the Contour Advance array. Pure-tone thresholds and speech perception data were retrospectively reviewed. Intervention Four subjects underwent reimplantation with the Nucleus Freedom or Nucleus 5 device after experiencing deteriorating performance related to delayed acoustic hearing loss. Comparison of pre-revision performance to the most recent post-revision performance demonstrated improved speech perception performance in all subjects following reimplantation. Conclusions A small percent of patients will experience a significant loss of residual low-frequency hearing following hybrid implantation thereby becoming completely reliant on a shorter electrode for electrical stimulation. In the current series, reimplantation with a conventional length electrode provided improved speech perception performance in such patients. Revision surgery with a conventional length electrode should be considered in ‘short electrode’ recipients who experience performance deterioration following loss of residual hearing. PMID:22333755

Effects of a cochlear implant simulation on immediate memory in normal-hearing adults

PubMed Central

Burkholder, Rose A.; Pisoni, David B.; Svirsky, Mario A.

2012-01-01

This study assessed the effects of stimulus misidentification and memory processing errors on immediate memory span in 25 normal-hearing adults exposed to degraded auditory input simulating signals provided by a cochlear implant. The identification accuracy of degraded digits in isolation was measured before digit span testing. Forward and backward digit spans were shorter when digits were degraded than when they were normal. Participants’ normal digit spans and their accuracy in identifying isolated digits were used to predict digit spans in the degraded speech condition. The observed digit spans in degraded conditions did not differ significantly from predicted digit spans. This suggests that the decrease in memory span is related primarily to misidentification of digits rather than memory processing errors related to cognitive load. These findings provide complementary information to earlier research on auditory memory span of listeners exposed to degraded speech either experimentally or as a consequence of a hearing-impairment. PMID:16317807

Biomedical Simulation Models of Human Auditory Processes

NASA Technical Reports Server (NTRS)

Bicak, Mehmet M. A.

2012-01-01

Detailed acoustic engineering models that explore noise propagation mechanisms associated with noise attenuation and transmission paths created when using hearing protectors such as earplugs and headsets in high noise environments. Biomedical finite element (FE) models are developed based on volume Computed Tomography scan data which provides explicit external ear, ear canal, middle ear ossicular bones and cochlea geometry. Results from these studies have enabled a greater understanding of hearing protector to flesh dynamics as well as prioritizing noise propagation mechanisms. Prioritization of noise mechanisms can form an essential framework for exploration of new design principles and methods in both earplug and earcup applications. These models are currently being used in development of a novel hearing protection evaluation system that can provide experimentally correlated psychoacoustic noise attenuation. Moreover, these FE models can be used to simulate the effects of blast related impulse noise on human auditory mechanisms and brain tissue.

Measuring listening effort: driving simulator vs. simple dual-task paradigm

PubMed Central

Wu, Yu-Hsiang; Aksan, Nazan; Rizzo, Matthew; Stangl, Elizabeth; Zhang, Xuyang; Bentler, Ruth

2014-01-01

Objectives The dual-task paradigm has been widely used to measure listening effort. The primary objectives of the study were to (1) investigate the effect of hearing aid amplification and a hearing aid directional technology on listening effort measured by a complicated, more real world dual-task paradigm, and (2) compare the results obtained with this paradigm to a simpler laboratory-style dual-task paradigm. Design The listening effort of adults with hearing impairment was measured using two dual-task paradigms, wherein participants performed a speech recognition task simultaneously with either a driving task in a simulator or a visual reaction-time task in a sound-treated booth. The speech materials and road noises for the speech recognition task were recorded in a van traveling on the highway in three hearing aid conditions: unaided, aided with omni directional processing (OMNI), and aided with directional processing (DIR). The change in the driving task or the visual reaction-time task performance across the conditions quantified the change in listening effort. Results Compared to the driving-only condition, driving performance declined significantly with the addition of the speech recognition task. Although the speech recognition score was higher in the OMNI and DIR conditions than in the unaided condition, driving performance was similar across these three conditions, suggesting that listening effort was not affected by amplification and directional processing. Results from the simple dual-task paradigm showed a similar trend: hearing aid technologies improved speech recognition performance, but did not affect performance in the visual reaction-time task (i.e., reduce listening effort). The correlation between listening effort measured using the driving paradigm and the visual reaction-time task paradigm was significant. The finding showing that our older (56 to 85 years old) participants’ better speech recognition performance did not result in reduced listening effort was not consistent with literature that evaluated younger (approximately 20 years old), normal hearing adults. Because of this, a follow-up study was conducted. In the follow-up study, the visual reaction-time dual-task experiment using the same speech materials and road noises was repeated on younger adults with normal hearing. Contrary to findings with older participants, the results indicated that the directional technology significantly improved performance in both speech recognition and visual reaction-time tasks. Conclusions Adding a speech listening task to driving undermined driving performance. Hearing aid technologies significantly improved speech recognition while driving, but did not significantly reduce listening effort. Listening effort measured by dual-task experiments using a simulated real-world driving task and a conventional laboratory-style task was generally consistent. For a given listening environment, the benefit of hearing aid technologies on listening effort measured from younger adults with normal hearing may not be fully translated to older listeners with hearing impairment. PMID:25083599

Music Perception with Cochlear Implants: A Review

PubMed Central

McDermott, Hugh J.

2004-01-01

The acceptance of cochlear implantation as an effective and safe treatment for deafness has increased steadily over the past quarter century. The earliest devices were the first implanted prostheses found to be successful in compensating partially for lost sensory function by direct electrical stimulation of nerves. Initially, the main intention was to provide limited auditory sensations to people with profound or total sensorineural hearing impairment in both ears. Although the first cochlear implants aimed to provide patients with little more than awareness of environmental sounds and some cues to assist visual speech-reading, the technology has advanced rapidly. Currently, most people with modern cochlear implant systems can understand speech using the device alone, at least in favorable listening conditions. In recent years, an increasing research effort has been directed towards implant users’ perception of nonspeech sounds, especially music. This paper reviews that research, discusses the published experimental results in terms of both psychophysical observations and device function, and concludes with some practical suggestions about how perception of music might be enhanced for implant recipients in the future. The most significant findings of past research are: (1) On average, implant users perceive rhythm about as well as listeners with normal hearing; (2) Even with technically sophisticated multiple-channel sound processors, recognition of melodies, especially without rhythmic or verbal cues, is poor, with performance at little better than chance levels for many implant users; (3) Perception of timbre, which is usually evaluated by experimental procedures that require subjects to identify musical instrument sounds, is generally unsatisfactory; (4) Implant users tend to rate the quality of musical sounds as less pleasant than listeners with normal hearing; (5) Auditory training programs that have been devised specifically to provide implant users with structured musical listening experience may improve the subjective acceptability of music that is heard through a prosthesis; (6) Pitch perception might be improved by designing innovative sound processors that use both temporal and spatial patterns of electric stimulation more effectively and precisely to overcome the inherent limitations of signal coding in existing implant systems; (7) For the growing population of implant recipients who have usable acoustic hearing, at least for low-frequency sounds, perception of music is likely to be much better with combined acoustic and electric stimulation than is typical for deaf people who rely solely on the hearing provided by their prostheses. PMID:15497033

Music perception with cochlear implants: a review.

PubMed

McDermott, Hugh J

2004-01-01

The acceptance of cochlear implantation as an effective and safe treatment for deafness has increased steadily over the past quarter century. The earliest devices were the first implanted prostheses found to be successful in compensating partially for lost sensory function by direct electrical stimulation of nerves. Initially, the main intention was to provide limited auditory sensations to people with profound or total sensorineural hearing impairment in both ears. Although the first cochlear implants aimed to provide patients with little more than awareness of environmental sounds and some cues to assist visual speech-reading, the technology has advanced rapidly. Currently, most people with modern cochlear implant systems can understand speech using the device alone, at least in favorable listening conditions. In recent years, an increasing research effort has been directed towards implant users' perception of nonspeech sounds, especially music. This paper reviews that research, discusses the published experimental results in terms of both psychophysical observations and device function, and concludes with some practical suggestions about how perception of music might be enhanced for implant recipients in the future. The most significant findings of past research are: (1) On average, implant users perceive rhythm about as well as listeners with normal hearing; (2) Even with technically sophisticated multiple-channel sound processors, recognition of melodies, especially without rhythmic or verbal cues, is poor, with performance at little better than chance levels for many implant users; (3) Perception of timbre, which is usually evaluated by experimental procedures that require subjects to identify musical instrument sounds, is generally unsatisfactory; (4) Implant users tend to rate the quality of musical sounds as less pleasant than listeners with normal hearing; (5) Auditory training programs that have been devised specifically to provide implant users with structured musical listening experience may improve the subjective acceptability of music that is heard through a prosthesis; (6) Pitch perception might be improved by designing innovative sound processors that use both temporal and spatial patterns of electric stimulation more effectively and precisely to overcome the inherent limitations of signal coding in existing implant systems; (7) For the growing population of implant recipients who have usable acoustic hearing, at least for low-frequency sounds, perception of music is likely to be much better with combined acoustic and electric stimulation than is typical for deaf people who rely solely on the hearing provided by their prostheses.

A Physiological Signal Transmission Model to be Used for Specific Diagnosis of Cochlear Impairments

NASA Astrophysics Data System (ADS)

Saremi, Amin; Stenfelt, Stefan

2011-11-01

Many of the sophisticated characteristics of human auditory system are attributed to cochlea. Also, most of patients with a hearing loss suffer from impairments that originate from cochlea (sensorineural). Despite this, today's clinical diagnosis methods do not probe the specific origins of such cochlear lesions. The aim of this research is to introduce a physiological signal transmission model to be clinically used as a tool for diagnosis of cochlear losses. This model enables simulation of different bio-mechano-electrical processes which occur in the auditory organ of Corti inside the cochlea. What makes this model different from many available computational models is its loyalty to physiology since the ultimate goal is to model each single physiological phenomenon. This includes passive BM vibration, outer hair cells' performances such as nonlinear mechanoelectrical transduction (MET), active amplifications by somatic motor, as well as vibration to neural conversion at the inner hair cells.

Effects of Additional Low-Pass-Filtered Speech on Listening Effort for Noise-Band-Vocoded Speech in Quiet and in Noise.

PubMed

Pals, Carina; Sarampalis, Anastasios; van Dijk, Mart; Başkent, Deniz

2018-05-11

Residual acoustic hearing in electric-acoustic stimulation (EAS) can benefit cochlear implant (CI) users in increased sound quality, speech intelligibility, and improved tolerance to noise. The goal of this study was to investigate whether the low-pass-filtered acoustic speech in simulated EAS can provide the additional benefit of reducing listening effort for the spectrotemporally degraded signal of noise-band-vocoded speech. Listening effort was investigated using a dual-task paradigm as a behavioral measure, and the NASA Task Load indeX as a subjective self-report measure. The primary task of the dual-task paradigm was identification of sentences presented in three experiments at three fixed intelligibility levels: at near-ceiling, 50%, and 79% intelligibility, achieved by manipulating the presence and level of speech-shaped noise in the background. Listening effort for the primary intelligibility task was reflected in the performance on the secondary, visual response time task. Experimental speech processing conditions included monaural or binaural vocoder, with added low-pass-filtered speech (to simulate EAS) or without (to simulate CI). In Experiment 1, in quiet with intelligibility near-ceiling, additional low-pass-filtered speech reduced listening effort compared with binaural vocoder, in line with our expectations, although not compared with monaural vocoder. In Experiments 2 and 3, for speech in noise, added low-pass-filtered speech allowed the desired intelligibility levels to be reached at less favorable speech-to-noise ratios, as expected. It is interesting that this came without the cost of increased listening effort usually associated with poor speech-to-noise ratios; at 50% intelligibility, even a reduction in listening effort on top of the increased tolerance to noise was observed. The NASA Task Load indeX did not capture these differences. The dual-task results provide partial evidence for a potential decrease in listening effort as a result of adding low-frequency acoustic speech to noise-band-vocoded speech. Whether these findings translate to CI users with residual acoustic hearing will need to be addressed in future research because the quality and frequency range of low-frequency acoustic sound available to listeners with hearing loss may differ from our idealized simulations, and additional factors, such as advanced age and varying etiology, may also play a role.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

Effects of hearing aid settings for electric-acoustic stimulation.

PubMed

Dillon, Margaret T; Buss, Emily; Pillsbury, Harold C; Adunka, Oliver F; Buchman, Craig A; Adunka, Marcia C

2014-02-01

Cochlear implant (CI) recipients with postoperative hearing preservation may utilize an ipsilateral bimodal listening condition known as electric-acoustic stimulation (EAS). Studies on EAS have reported significant improvements in speech perception abilities over CI-alone listening conditions. Adjustments to the hearing aid (HA) settings to match prescription targets routinely used in the programming of conventional amplification may provide additional gains in speech perception abilities. Investigate the difference in users' speech perception scores when listening with the recommended HA settings for EAS patients versus HA settings adjusted to match National Acoustic Laboratories' nonlinear fitting procedure version 1 (NAL-NL1) targets. Prospective analysis of the influence of HA settings. Nine EAS recipients with greater than 12 mo of listening experience with the DUET speech processor. Subjects were tested in the EAS listening condition with two different HA setting configurations. Speech perception materials included consonant-nucleus-consonant (CNC) words in quiet, AzBio sentences in 10-talker speech babble at a signal-to-noise ratio (SNR) of +10, and the Bamford-Kowal-Bench sentences in noise (BKB-SIN) test. The speech perception performance on each test measure was compared between the two HA configurations. Subjects experienced a significant improvement in speech perception abilities with the HA settings adjusted to match NAL-NL1 targets over the recommended HA settings. EAS subjects have been shown to experience improvements in speech perception abilities when listening to ipsilateral combined stimulation. This population's abilities may be underestimated with current HA settings. Tailoring the HA output to the patient's individual hearing loss offers improved outcomes on speech perception measures. American Academy of Audiology.

The impact of hearing aids and age-related hearing loss on auditory plasticity across three months - An electrical neuroimaging study.

PubMed

Giroud, Nathalie; Lemke, Ulrike; Reich, Philip; Matthes, Katarina L; Meyer, Martin

2017-09-01

The present study investigates behavioral and electrophysiological auditory and cognitive-related plasticity in three groups of healthy older adults (60-77 years). Group 1 was moderately hearing-impaired, experienced hearing aid users, and fitted with new hearing aids using non-linear frequency compression (NLFC on); Group 2, also moderately hearing-impaired, used the same type of hearing aids but NLFC was switched off during the entire period of study duration (NLFC off); Group 3 represented individuals with age-appropriate hearing (NHO) as controls, who were not different in IQ, gender, or age from Group 1 and 2. At five measurement time points (M1-M5) across three months, a series of active oddball tasks were administered while EEG was recorded. The stimuli comprised syllables consisting of naturally high-pitched fricatives (/sh/, /s/, and /f/), which are hard to distinguish for individuals with presbycusis. By applying a data-driven microstate approach to obtain global field power (GFP) as a measure of processing effort, the modulations of perceptual (P50, N1, P2) and cognitive-related (N2b, P3b) auditory evoked potentials were calculated and subsequently related to behavioral changes (accuracy and reaction time) across time. All groups improved their performance across time, but NHO showed consistently higher accuracy and faster reaction times than the hearing-impaired groups, especially under difficult conditions. Electrophysiological results complemented this finding by demonstrating longer latencies in the P50 and the N1 peak in hearing aid users. Furthermore, the GFP of cognitive-related evoked potentials decreased from M1 to M2 in the NHO group, while a comparable decrease in the hearing-impaired group was only evident at M5. After twelve weeks of hearing aid use of eight hours each day, we found a significantly lower GFP in the P3b of the group with NLFC on as compared to the group with NLFC off. These findings suggest higher processing effort, as evidenced by higher GFP, in hearing-impaired individuals when compared to those with normal hearing, although the hearing-impaired show a decrease of processing effort after repeated stimulus exposure. In addition, our findings indicate that the acclimatization to a new hearing aid algorithm may take several weeks. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Binaural fusion and listening effort in children who use bilateral cochlear implants: a psychoacoustic and pupillometric study.

PubMed

Steel, Morrison M; Papsin, Blake C; Gordon, Karen A

2015-01-01

Bilateral cochlear implants aim to provide hearing to both ears for children who are deaf and promote binaural/spatial hearing. Benefits are limited by mismatched devices and unilaterally-driven development which could compromise the normal integration of left and right ear input. We thus asked whether children hear a fused image (ie. 1 vs 2 sounds) from their bilateral implants and if this "binaural fusion" reduces listening effort. Binaural fusion was assessed by asking 25 deaf children with cochlear implants and 24 peers with normal hearing whether they heard one or two sounds when listening to bilaterally presented acoustic click-trains/electric pulses (250 Hz trains of 36 ms presented at 1 Hz). Reaction times and pupillary changes were recorded simultaneously to measure listening effort. Bilaterally implanted children heard one image of bilateral input less frequently than normal hearing peers, particularly when intensity levels on each side were balanced. Binaural fusion declined as brainstem asymmetries increased and age at implantation decreased. Children implanted later had access to acoustic input prior to implantation due to progressive deterioration of hearing. Increases in both pupil diameter and reaction time occurred as perception of binaural fusion decreased. Results indicate that, without binaural level cues, children have difficulty fusing input from their bilateral implants to perceive one sound which costs them increased listening effort. Brainstem asymmetries exacerbate this issue. By contrast, later implantation, reflecting longer access to bilateral acoustic hearing, may have supported development of auditory pathways underlying binaural fusion. Improved integration of bilateral cochlear implant signals for children is required to improve their binaural hearing.

Loudness of dynamic stimuli in acoustic and electric hearing.

PubMed

Zhang, C; Zeng, F G

1997-11-01

Traditional loudness models have been based on the average energy and the critical band analysis of steady-state sounds. However, most environmental sounds, including speech, are dynamic stimuli, in which the average level [e.g., the root-mean-square (rms) level] does not account for the large temporal fluctuations. The question addressed here was whether two stimuli of the same rms level but different peak levels would produce an equal loudness sensation. A modern adaptive procedure was used to replicate two classic experiments demonstrating that the sensation of "beats" in a two- or three-tone complex resulted in a louder sensation [E. Zwicker and H. Fastl, Psychoacoustics-Facts and Models (Springer-Verlag, Berlin, 1990)]. Two additional experiments were conducted to study exclusively the effects of the temporal envelope on the loudness sensation of dynamic stimuli. Loudness balance was performed by normal-hearing listeners between a white noise and a sinusoidally amplitude-modulated noise in one experiment, and by cochlear implant listeners between two harmonic stimuli of the same magnitude spectra, but different phase spectra, in the other experiment. The results from both experiments showed that, for two stimuli of the same rms level, the stimulus with greater temporal fluctuations sometimes produced a significantly louder sensation, depending on the temporal frequency and overall stimulus level. In normal-hearing listeners, the louder sensation was produced for the amplitude-modulated stimuli with modulation frequencies lower than 400 Hz, and gradually disappeared above 400 Hz, resulting in a low-pass filtering characteristic which bore some similarity to the temporal modulation transfer function. The extent to which loudness was greater was a nonmonotonic function of level in acoustic hearing and a monotonically increasingly function in electric hearing. These results suggest that the loudness sensation of a dynamic stimulus is not limited to a 100-ms temporal integration process, and may be determined jointly by a compression process in the cochlea and an expansion process in the brain. A level-dependent compression scheme that may better restore normal loudness of dynamic stimuli in hearing aids and cochlear implants is proposed.

Chronic suppurative otitis media in children of Luanda, Angola.

PubMed

Taipale, Anni; Pelkonen, Tuula; Taipale, Marko; Bernardino, Luis; Peltola, Heikki; Pitkäranta, Anne

2011-08-01

Evaluation of clinical characteristics, bacteriology and hearing in paediatric patients with and without chronic suppurative otitis media (CSOM) in Luanda, Angola. Interview, clinical examination, ear-discharge culture, open air pure-tone audiometry and brainstem auditory-evoked potentials of 23 outpatients with CSOM and 23 controls in a paediatric hospital. Of the CSOM vs. control children, 35% vs. 26% had running water, 70% vs. 70% electricity, 64% vs. 0% HIV (p<0.0001) and 36% vs. 0% tuberculosis in history (p=0.002). Ten (43%) children had bilateral CSOM. The major ear-discharge pathogens were Proteus spp. (44%) and Pseudomonas (22%). Hearing impairment of >25 dB was present in 52% of CSOM-affected ears and bilateral hearing loss in 7 (30%) CSOM children vs. zero control child (p=0.009). Only one hearing-impaired child's family had previously detected the handicap. CSOM occurred in children with high co-morbidity. Persistent otorrhoea was usually caused by Proteus spp. or Pseudomonas, and often suggestive of either HIV or hearing impairment. In the developing countries, prompt diagnosis and treatment of CSOM would enhance the children's linguistic and academic development. © 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.

Speech perception benefits of internet versus conventional telephony for hearing-impaired individuals.

PubMed

Mantokoudis, Georgios; Dubach, Patrick; Pfiffner, Flurin; Kompis, Martin; Caversaccio, Marco; Senn, Pascal

2012-07-16

Telephone communication is a challenge for many hearing-impaired individuals. One important technical reason for this difficulty is the restricted frequency range (0.3-3.4 kHz) of conventional landline telephones. Internet telephony (voice over Internet protocol [VoIP]) is transmitted with a larger frequency range (0.1-8 kHz) and therefore includes more frequencies relevant to speech perception. According to a recently published, laboratory-based study, the theoretical advantage of ideal VoIP conditions over conventional telephone quality has translated into improved speech perception by hearing-impaired individuals. However, the speech perception benefits of nonideal VoIP network conditions, which may occur in daily life, have not been explored. VoIP use cannot be recommended to hearing-impaired individuals before its potential under more realistic conditions has been examined. To compare realistic VoIP network conditions, under which digital data packets may be lost, with ideal conventional telephone quality with respect to their impact on speech perception by hearing-impaired individuals. We assessed speech perception using standardized test material presented under simulated VoIP conditions with increasing digital data packet loss (from 0% to 20%) and compared with simulated ideal conventional telephone quality. We monaurally tested 10 adult users of cochlear implants, 10 adult users of hearing aids, and 10 normal-hearing adults in the free sound field, both in quiet and with background noise. Across all participant groups, mean speech perception scores using VoIP with 0%, 5%, and 10% packet loss were 15.2% (range 0%-53%), 10.6% (4%-46%), and 8.8% (7%-33%) higher, respectively, than with ideal conventional telephone quality. Speech perception did not differ between VoIP with 20% packet loss and conventional telephone quality. The maximum benefits were observed under ideal VoIP conditions without packet loss and were 36% (P = .001) for cochlear implant users, 18% (P = .002) for hearing aid users, and 53% (P = .001) for normal-hearing adults. With a packet loss of 10%, the maximum benefits were 30% (P = .002) for cochlear implant users, 6% (P = .38) for hearing aid users, and 33% (P = .002) for normal-hearing adults. VoIP offers a speech perception benefit over conventional telephone quality, even when mild or moderate packet loss scenarios are created in the laboratory. VoIP, therefore, has the potential to significantly improve telecommunication abilities for the large community of hearing-impaired individuals.

Speech Perception Benefits of Internet Versus Conventional Telephony for Hearing-Impaired Individuals

PubMed Central

Dubach, Patrick; Pfiffner, Flurin; Kompis, Martin; Caversaccio, Marco

2012-01-01

Background Telephone communication is a challenge for many hearing-impaired individuals. One important technical reason for this difficulty is the restricted frequency range (0.3–3.4 kHz) of conventional landline telephones. Internet telephony (voice over Internet protocol [VoIP]) is transmitted with a larger frequency range (0.1–8 kHz) and therefore includes more frequencies relevant to speech perception. According to a recently published, laboratory-based study, the theoretical advantage of ideal VoIP conditions over conventional telephone quality has translated into improved speech perception by hearing-impaired individuals. However, the speech perception benefits of nonideal VoIP network conditions, which may occur in daily life, have not been explored. VoIP use cannot be recommended to hearing-impaired individuals before its potential under more realistic conditions has been examined. Objective To compare realistic VoIP network conditions, under which digital data packets may be lost, with ideal conventional telephone quality with respect to their impact on speech perception by hearing-impaired individuals. Methods We assessed speech perception using standardized test material presented under simulated VoIP conditions with increasing digital data packet loss (from 0% to 20%) and compared with simulated ideal conventional telephone quality. We monaurally tested 10 adult users of cochlear implants, 10 adult users of hearing aids, and 10 normal-hearing adults in the free sound field, both in quiet and with background noise. Results Across all participant groups, mean speech perception scores using VoIP with 0%, 5%, and 10% packet loss were 15.2% (range 0%–53%), 10.6% (4%–46%), and 8.8% (7%–33%) higher, respectively, than with ideal conventional telephone quality. Speech perception did not differ between VoIP with 20% packet loss and conventional telephone quality. The maximum benefits were observed under ideal VoIP conditions without packet loss and were 36% (P = .001) for cochlear implant users, 18% (P = .002) for hearing aid users, and 53% (P = .001) for normal-hearing adults. With a packet loss of 10%, the maximum benefits were 30% (P = .002) for cochlear implant users, 6% (P = .38) for hearing aid users, and 33% (P = .002) for normal-hearing adults. Conclusions VoIP offers a speech perception benefit over conventional telephone quality, even when mild or moderate packet loss scenarios are created in the laboratory. VoIP, therefore, has the potential to significantly improve telecommunication abilities for the large community of hearing-impaired individuals. PMID:22805169

Voiceprints: Hearing for Those Who Can't?

ERIC Educational Resources Information Center

Science News, 1979

1979-01-01

An electrical engineer and phoneticist has taught himself to read voiceprints, spectrograms that display a plot of the sound frequency of speech against time. This technique may prove useful in training the deaf to read voiceprints or to mimic natural speech. (BB)

Bringing Hearing to the Deaf--Cochlear Implants: a Technical and Personal Account

NASA Astrophysics Data System (ADS)

Shipsey, Ian

2006-04-01

Cochlear implants are the first device to successfully restore neural function. They have instigated a popular but controversial revolution in the treatment of deafness, and they serve as a model for research in neuroscience and biomedical engineering. In this talk the physiology of natural hearing will be reviewed from the perspective of a physicist, and the function of cochlear implants will be described in the context of historical treatments, electrical engineering, psychophysics, clinical evaluation of efficacy and personal experience. The social implications of cochlear implantation and the future outlook for auditory prostheses will also be discussed.

Electric and magnetic fields. Hearing before the Subcommittee on Energy and Power of the Committee on Energy and Commerce, House of Representatives, One Hundred Third Congress, First Session, April 1, 1993

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

Not Available

1993-01-01

This hearing focuses on progress on implementing federal legislation establishing a coordinated Federal research and public information program in Electromagnetic fields. Testimony is given by F.Keith, Center for Risk Management, Resources for the Future; R. Neutra, Environmental Health Investigations, California Department of Health Services; K.Olden, National Institute of Environmental Health Sciences; R. San Martin, Acting Ass Sec, Conservation and Renewable Energy, DOE; T. Tenforde, Life Sciences Center, Battelle Pacific Northwest Laboratories.

Melodic contour identification and sentence recognition using sung speech

PubMed Central

Crew, Joseph D.; Galvin, John J.; Fu, Qian-Jie

2015-01-01

For bimodal cochlear implant users, acoustic and electric hearing has been shown to contribute differently to speech and music perception. However, differences in test paradigms and stimuli in speech and music testing can make it difficult to assess the relative contributions of each device. To address these concerns, the Sung Speech Corpus (SSC) was created. The SSC contains 50 monosyllable words sung over an octave range and can be used to test both speech and music perception using the same stimuli. Here SSC data are presented with normal hearing listeners and any advantage of musicianship is examined. PMID:26428838

The effect of different cochlear implant microphones on acoustic hearing individuals’ binaural benefits for speech perception in noise

PubMed Central

Aronoff, Justin M.; Freed, Daniel J.; Fisher, Laurel M.; Pal, Ivan; Soli, Sigfrid D.

2011-01-01

Objectives Cochlear implant microphones differ in placement, frequency response, and other characteristics such as whether they are directional. Although normal hearing individuals are often used as controls in studies examining cochlear implant users’ binaural benefits, the considerable differences across cochlear implant microphones make such comparisons potentially misleading. The goal of this study was to examine binaural benefits for speech perception in noise for normal hearing individuals using stimuli processed by head-related transfer functions (HRTFs) based on the different cochlear implant microphones. Design HRTFs were created for different cochlear implant microphones and used to test participants on the Hearing in Noise Test. Experiment 1 tested cochlear implant users and normal hearing individuals with HRTF-processed stimuli and with sound field testing to determine whether the HRTFs adequately simulated sound field testing. Experiment 2 determined the measurement error and performance-intensity function for the Hearing in Noise Test with normal hearing individuals listening to stimuli processed with the various HRTFs. Experiment 3 compared normal hearing listeners’ performance across HRTFs to determine how the HRTFs affected performance. Experiment 4 evaluated binaural benefits for normal hearing listeners using the various HRTFs, including ones that were modified to investigate the contributions of interaural time and level cues. Results The results indicated that the HRTFs adequately simulated sound field testing for the Hearing in Noise Test. They also demonstrated that the test-retest reliability and performance-intensity function were consistent across HRTFs, and that the measurement error for the test was 1.3 dB, with a change in signal-to-noise ratio of 1 dB reflecting a 10% change in intelligibility. There were significant differences in performance when using the various HRTFs, with particularly good thresholds for the HRTF based on the directional microphone when the speech and masker were spatially separated, emphasizing the importance of measuring binaural benefits separately for each HRTF. Evaluation of binaural benefits indicated that binaural squelch and spatial release from masking were found for all HRTFs and binaural summation was found for all but one HRTF, although binaural summation was less robust than the other types of binaural benefits. Additionally, the results indicated that neither interaural time nor level cues dominated binaural benefits for the normal hearing participants. Conclusions This study provides a means to measure the degree to which cochlear implant microphones affect acoustic hearing with respect to speech perception in noise. It also provides measures that can be used to evaluate the independent contributions of interaural time and level cues. These measures provide tools that can aid researchers in understanding and improving binaural benefits in acoustic hearing individuals listening via cochlear implant microphones. PMID:21412155

Evidence-based occupational hearing screening II: validation of a screening methodology using measures of functional hearing ability.

PubMed

Soli, Sigfrid D; Amano-Kusumoto, Akiko; Clavier, Odile; Wilbur, Jed; Casto, Kristen; Freed, Daniel; Laroche, Chantal; Vaillancourt, Véronique; Giguère, Christian; Dreschler, Wouter A; Rhebergen, Koenraad S

2018-05-01

Validate use of the Extended Speech Intelligibility Index (ESII) for prediction of speech intelligibility in non-stationary real-world noise environments. Define a means of using these predictions for objective occupational hearing screening for hearing-critical public safety and law enforcement jobs. Analyses of predicted and measured speech intelligibility in recordings of real-world noise environments were performed in two studies using speech recognition thresholds (SRTs) and intelligibility measures. ESII analyses of the recordings were used to predict intelligibility. Noise recordings were made in prison environments and at US Army facilities for training ground and airborne forces. Speech materials included full bandwidth sentences and bandpass filtered sentences that simulated radio transmissions. A total of 22 adults with normal hearing (NH) and 15 with mild-moderate hearing impairment (HI) participated in the two studies. Average intelligibility predictions for individual NH and HI subjects were accurate in both studies (r 2  ≥ 0.94). Pooled predictions were slightly less accurate (0.78 ≤ r 2  ≤ 0.92). An individual's SRT and audiogram can accurately predict the likelihood of effective speech communication in noise environments with known ESII characteristics, where essential hearing-critical tasks are performed. These predictions provide an objective means of occupational hearing screening.

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

PubMed

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

2018-01-01

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

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

PubMed Central

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

2018-01-01

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

Effects of Hearing Preservation on Psychophysical Responses to Cochlear Implant Stimulation

PubMed Central

Kang, Stephen Y.; Colesa, Deborah J.; Swiderski, Donald L.; Su, Gina L.; Raphael, Yehoash

2009-01-01

Previous studies have shown that residual acoustic hearing supplements cochlear implant function to improve speech recognition in noise as well as perception of music. The current study had two primary objectives. First, we sought to determine how cochlear implantation and electrical stimulation over a time period of 14 to 21 months influence cochlear structures such as hair cells and spiral ganglion neurons. Second, we sought to investigate whether the structures that provide acoustic hearing also affect the perception of electrical stimulation. We compared psychophysical responses to cochlear implant stimulation in two groups of adult guinea pigs. Group I (11 animals) received a cochlear implant in a previously untreated ear, while group II (ten animals) received a cochlear implant in an ear that had been previously infused with neomycin to destroy hearing. Psychophysical thresholds were measured in response to pulse-train and sinusoidal stimuli. Histological analysis of all group I animals and a subset of group II animals was performed. Nine of the 11 group I animals showed survival of the organ of Corti and spiral ganglion neurons adjacent to the electrode array. All group I animals showed survival of these elements in regions apical to the electrode array. Group II animals that were examined histologically showed complete loss of the organ of Corti in regions adjacent and apical to the electrode array and severe spiral ganglion neuron loss, consistent with previous reports for neomycin-treated ears. Behaviorally, group II animals had significantly lower thresholds than group I animals in response to 100 Hz sinusoidal stimuli. However, group I animals had significantly lower thresholds than group II animals in response to pulse-train stimuli (0.02 ms/phase; 156 to 5,000 pps). Additionally, the two groups showed distinct threshold versus pulse rate functions. We hypothesize that the differences in detection thresholds between groups are caused by the electrical activation of the hair cells in group I animals and/or differences between groups in the condition of the spiral ganglion neurons. PMID:19902297

A false killer whale adjusts its hearing when it echolocates.

PubMed

Nachtigall, Paul E; Supin, Alexander Y

2008-06-01

The use of auditory evoked potential (AEP) measurements has added considerably to knowledge of the hearing mechanisms of marine mammals. We have recently measured the hearing of a stranded infant Risso's dolphin, the audiograms of white-beaked dolphins temporarily caught and released, and the hearing of anaesthetized polar bears. Most small toothed whales echolocate and hear very high frequency sounds underwater. While much has previously been learned about the echolocation performance and characteristics of the outgoing signals of echolocating dolphins and small whales, the hearing processes occurring while these animals actively echolocate have not previously been examined. Working with a well-trained echolocating false killer whale (Pseudorca crassidens) wearing latex surface suction cup electrodes, we have measured echolocation hearing AEPs in response to outgoing echolocation clicks, returning echoes, and comparable simulated whale clicks and echoes in a variety of situations. We have found that: (1) the whale may hear her loud outgoing clicks and much quieter returning echoes at comparable levels, (2) the whale has protective mechanisms that dampen the intensity of her outgoing signals - she hears her outgoing signals at a level about 40 dB lower than similar signals presented directly in front of her, (3) when echo return levels are lowered either by making the targets smaller or by placing the targets farther away - without changing the levels of her outgoing signals - the hearing of these echoes remains at almost the same level, (4) if targets are made much smaller and harder to echolocate, the animal will modify what she hears of her outgoing signal - as if to heighten overall hearing sensitivity to keep the echo level hearable, (5) the animal has an active 'automatic gain control' mechanism in her hearing based on both forward masking that balances outgoing pulse intensity and time between pulse and echo, and active hearing control. Overall, hearing during echolocation appears to be a very active process.

Binaural Fusion and Listening Effort in Children Who Use Bilateral Cochlear Implants: A Psychoacoustic and Pupillometric Study

PubMed Central

Steel, Morrison M.; Papsin, Blake C.; Gordon, Karen A.

2015-01-01

Bilateral cochlear implants aim to provide hearing to both ears for children who are deaf and promote binaural/spatial hearing. Benefits are limited by mismatched devices and unilaterally-driven development which could compromise the normal integration of left and right ear input. We thus asked whether children hear a fused image (ie. 1 vs 2 sounds) from their bilateral implants and if this “binaural fusion” reduces listening effort. Binaural fusion was assessed by asking 25 deaf children with cochlear implants and 24 peers with normal hearing whether they heard one or two sounds when listening to bilaterally presented acoustic click-trains/electric pulses (250 Hz trains of 36 ms presented at 1 Hz). Reaction times and pupillary changes were recorded simultaneously to measure listening effort. Bilaterally implanted children heard one image of bilateral input less frequently than normal hearing peers, particularly when intensity levels on each side were balanced. Binaural fusion declined as brainstem asymmetries increased and age at implantation decreased. Children implanted later had access to acoustic input prior to implantation due to progressive deterioration of hearing. Increases in both pupil diameter and reaction time occurred as perception of binaural fusion decreased. Results indicate that, without binaural level cues, children have difficulty fusing input from their bilateral implants to perceive one sound which costs them increased listening effort. Brainstem asymmetries exacerbate this issue. By contrast, later implantation, reflecting longer access to bilateral acoustic hearing, may have supported development of auditory pathways underlying binaural fusion. Improved integration of bilateral cochlear implant signals for children is required to improve their binaural hearing. PMID:25668423

Behavioral responses of deafened guinea pigs to intracochlear electrical stimulation: a new rapid psychophysical procedure.

PubMed

Agterberg, Martijn J H; Versnel, Huib

2014-07-01

In auditory research the guinea pig is often preferred above rats and mice because of the easily accessible cochlea and because the frequency range of its hearing is more comparable to that of humans. Studies of the guinea-pig auditory system primarily apply histological and electrophysiological measures. Behavioral animal paradigms, in particular in combination with these histological and electrophysiological methods, are necessary in the development of new therapeutic interventions. However, the guinea pig is not considered an attractive animal for behavioral experiments. Therefore, the purpose of this study was to develop a behavioral task suitable for guinea pigs, that can be utilized in cochlear-implant related research. Guinea pigs were trained in a modified shuttle-box in which a stream of air was used as unconditioned stimulus (UCS). A stream of air was preferred over conventionally used methods as electric foot-shocks since it produces less stress, which is a confounding factor in behavioral experiments. Hearing guinea pigs were trained to respond to acoustic stimuli. They responded correctly within only five sessions of ten minutes. The animals maintained their performance four weeks after the right cochlea was implanted with an electrode array. After systemic deafening, the animals responded in the first session immediately to intracochlear electrical stimulation. These responses were not affected by daily chronic electrical stimulation (CES). In conclusion, the present study demonstrates that guinea pigs can be trained relatively fast to respond to acoustic stimuli, and that the training has a lasting effect, which generalizes to intracochlear electrical stimulation after deafening. Furthermore, it demonstrates that bilaterally deafened guinea pigs with substantial (∼50%) loss of spiral ganglion cells (SGCs), detect intracochlear electrical stimulation. Copyright © 2014 Elsevier B.V. All rights reserved.

Objective Prediction of Hearing Aid Benefit Across Listener Groups Using Machine Learning: Speech Recognition Performance With Binaural Noise-Reduction Algorithms.

PubMed

Schädler, Marc R; Warzybok, Anna; Kollmeier, Birger

2018-01-01

The simulation framework for auditory discrimination experiments (FADE) was adopted and validated to predict the individual speech-in-noise recognition performance of listeners with normal and impaired hearing with and without a given hearing-aid algorithm. FADE uses a simple automatic speech recognizer (ASR) to estimate the lowest achievable speech reception thresholds (SRTs) from simulated speech recognition experiments in an objective way, independent from any empirical reference data. Empirical data from the literature were used to evaluate the model in terms of predicted SRTs and benefits in SRT with the German matrix sentence recognition test when using eight single- and multichannel binaural noise-reduction algorithms. To allow individual predictions of SRTs in binaural conditions, the model was extended with a simple better ear approach and individualized by taking audiograms into account. In a realistic binaural cafeteria condition, FADE explained about 90% of the variance of the empirical SRTs for a group of normal-hearing listeners and predicted the corresponding benefits with a root-mean-square prediction error of 0.6 dB. This highlights the potential of the approach for the objective assessment of benefits in SRT without prior knowledge about the empirical data. The predictions for the group of listeners with impaired hearing explained 75% of the empirical variance, while the individual predictions explained less than 25%. Possibly, additional individual factors should be considered for more accurate predictions with impaired hearing. A competing talker condition clearly showed one limitation of current ASR technology, as the empirical performance with SRTs lower than -20 dB could not be predicted.

Individual Differences in Auditory Brainstem Response Wave Characteristics

PubMed Central

Jagadeesh, Anoop; Mauermann, Manfred; Ernst, Frauke

2016-01-01

Little is known about how outer hair cell loss interacts with noise-induced and age-related auditory nerve degradation (i.e., cochlear synaptopathy) to affect auditory brainstem response (ABR) wave characteristics. Given that listeners with impaired audiograms likely suffer from mixtures of these hearing deficits and that ABR amplitudes have successfully been used to isolate synaptopathy in listeners with normal audiograms, an improved understanding of how different hearing pathologies affect the ABR source generators will improve their sensitivity in hearing diagnostics. We employed a functional model for human ABRs in which different combinations of hearing deficits were simulated and show that high-frequency cochlear gain loss steepens the slope of the ABR Wave-V latency versus intensity and amplitude versus intensity curves. We propose that grouping listeners according to a ratio of these slope metrics (i.e., the ABR growth ratio) might offer a way to factor out the outer hair cell loss deficit and maximally relate individual differences for constant ratios to other peripheral hearing deficits such as cochlear synaptopathy. We compared the model predictions to recorded click-ABRs from 30 participants with normal or high-frequency sloping audiograms and confirm the predicted relationship between the ABR latency growth curve and audiogram slope. Experimental ABR amplitude growth showed large individual differences and was compared with the Wave-I amplitude, Wave-V/I ratio, or the interwaveI–W latency in the same listeners. The model simulations along with the ABR recordings suggest that a hearing loss profile depicting the ABR growth ratio versus the Wave-I amplitude or Wave-V/I ratio might be able to differentiate outer hair cell deficits from cochlear synaptopathy in listeners with mixed pathologies. PMID:27837052

Objective Prediction of Hearing Aid Benefit Across Listener Groups Using Machine Learning: Speech Recognition Performance With Binaural Noise-Reduction Algorithms

PubMed Central

Schädler, Marc R.; Warzybok, Anna; Kollmeier, Birger

2018-01-01

The simulation framework for auditory discrimination experiments (FADE) was adopted and validated to predict the individual speech-in-noise recognition performance of listeners with normal and impaired hearing with and without a given hearing-aid algorithm. FADE uses a simple automatic speech recognizer (ASR) to estimate the lowest achievable speech reception thresholds (SRTs) from simulated speech recognition experiments in an objective way, independent from any empirical reference data. Empirical data from the literature were used to evaluate the model in terms of predicted SRTs and benefits in SRT with the German matrix sentence recognition test when using eight single- and multichannel binaural noise-reduction algorithms. To allow individual predictions of SRTs in binaural conditions, the model was extended with a simple better ear approach and individualized by taking audiograms into account. In a realistic binaural cafeteria condition, FADE explained about 90% of the variance of the empirical SRTs for a group of normal-hearing listeners and predicted the corresponding benefits with a root-mean-square prediction error of 0.6 dB. This highlights the potential of the approach for the objective assessment of benefits in SRT without prior knowledge about the empirical data. The predictions for the group of listeners with impaired hearing explained 75% of the empirical variance, while the individual predictions explained less than 25%. Possibly, additional individual factors should be considered for more accurate predictions with impaired hearing. A competing talker condition clearly showed one limitation of current ASR technology, as the empirical performance with SRTs lower than −20 dB could not be predicted. PMID:29692200

Preliminary Outcomes Report for CO2 Laser Assisted Electric-Acoustic Cochlear Implantation.

PubMed

Stevens, Shawn M; Redmann, Andrew; Whitaker, Kayla; Ruotanen, Alyson; Houston, Lisa; Hammer, Theresa; Samy, Ravi N

2018-06-01

Report on the safety/efficacy of a novel, carbon dioxide (CO2) laser-assisted protocol for hearing-preservation cochlear implantation (HPCI) and electric-acoustic stimulation (EAS). Retrospective case review. Tertiary referral center. Adult patients meeting established criteria for HPCI and EAS. Therapeutic/rehabilitative. A standardized protocol used CO2 laser to achieve meticulous hemostasis and perform cochleostomy was evaluated. Audiometric assessments included low-tone pure tone average (LtPTA), consonant-nucleus-consonant (CNC), and AzBio scores. Primary outcomes were low-tone hearing-preservation (LtHP) and EAS usage rates. Secondary outcomes included change in LtPTA, outcomes durability, and the rate/onset/presentation of delayed hearing loss (DHL). Subset analyses stratified data by presenting LtPTA and surgeon experience. Forty-seven patients and 52 ears were included. Mean follow-up was 20.7 ± 12.6 months. When adjusted for preoperative LtPTA less than 60 dB, the LtHP rate was 77%. This was significantly better than for patients with LtPTA more than 60 dB (24%; p < 0.0001). Outcomes were highly durable. EAS usage was excellent in those with LtPTA less than 60 dB (100%). Nine patients developed DHL. Three additional patients (25%) were successfully salvaged via steroids. Both CNC and AzBio scores improved significantly (p < 0.0001) at definitive testing. Speech-hearing scores did not differ significantly between patients using/not using EAS. The complication rate was 3.8%; none were caused by the laser. Surgeon experience was associated with significantly better outcomes. Use of a CO2 laser-assisted HPCI protocol was safe and effective. Outcomes were consistent with contemporary literature reporting. Patient selection and surgeon experience both significantly impacted outcomes.

Measurement and numerical simulation of the changes in the open-loop transfer function in hearing aid as a function telephone handset proximity

NASA Astrophysics Data System (ADS)

Daigle, Gilles A.; Stinson, Michael R.

2002-11-01

The presence of a nearby object (telephone handset, cupped hand, etc.) can cause acoustical feedback to occur in a hearing aid. The object reflects or scatters additional sound energy to the microphone position causing the open-loop transfer function (OLTF) to increase. Feedback can occur when the OLTF>0 dB. To investigate this problem, measurements of the OLTF were made for three hearing aids (BTE, ITC, ITE) mounted on a KEMAR manikin. A telephone handset, positioned initially in a typical user position, was translated to positions between 0 and 100 mm away from the pinna, repeatibly, using a linear translation system. Changes of up to 15 dB or more were observed as the handset moved, particularly for positions within 20 mm of the pinna. In parallel, numerical simulations were made using a boundary element method. Computed changes in OLTF were consistent with the measured changes.

Using the Real-Ear-to-Coupler Difference within the American Academy of Audiology Pediatric Amplification Guideline: Protocols for Applying and Predicting Earmold RECDs.

PubMed

Moodie, Sheila; Pietrobon, Jonathan; Rall, Eileen; Lindley, George; Eiten, Leisha; Gordey, Dave; Davidson, Lisa; Moodie, K Shane; Bagatto, Marlene; Haluschak, Meredith Magathan; Folkeard, Paula; Scollie, Susan

2016-03-01

Real-ear-to-coupler difference (RECD) measurements are used for the purposes of estimating degree and configuration of hearing loss (in dB SPL ear canal) and predicting hearing aid output from coupler-based measures. Accurate measurements of hearing threshold, derivation of hearing aid fitting targets, and predictions of hearing aid output in the ear canal assume consistent matching of RECD coupling procedure (i.e., foam tip or earmold) with that used during assessment and in verification of the hearing aid fitting. When there is a mismatch between these coupling procedures, errors are introduced. The goal of this study was to quantify the systematic difference in measured RECD values obtained when using a foam tip versus an earmold with various tube lengths. Assuming that systematic errors exist, the second goal was to investigate the use of a foam tip to earmold correction for the purposes of improving fitting accuracy when mismatched RECD coupling conditions occur (e.g., foam tip at assessment, earmold at verification). Eighteen adults and 17 children (age range: 3-127 mo) participated in this study. Data were obtained using simulated ears of various volumes and earmold tubing lengths and from patients using their own earmolds. Derived RECD values based on simulated ear measurements were compared with RECD values obtained for adult and pediatric ears for foam tip and earmold coupling. Results indicate that differences between foam tip and earmold RECDs are consistent across test ears for adults and children which support the development of a correction between foam tip and earmold couplings for RECDs that can be applied across individuals. The foam tip to earmold correction values developed in this study can be used to provide improved estimations of earmold RECDs. This may support better accuracy in acoustic transforms related to transforming thresholds and/or hearing aid coupler responses to ear canal sound pressure level for the purposes of fitting behind-the-ear hearing aids. American Academy of Audiology.

A preliminary report of music-based training for adult cochlear implant users: Rationales and development.

PubMed

Gfeller, Kate; Guthe, Emily; Driscoll, Virginia; Brown, Carolyn J

2015-09-01

This paper provides a preliminary report of a music-based training program for adult cochlear implant (CI) recipients. Included in this report are descriptions of the rationale for music-based training, factors influencing program development, and the resulting program components. Prior studies describing experience-based plasticity in response to music training, auditory training for persons with hearing impairment, and music training for CI recipients were reviewed. These sources revealed rationales for using music to enhance speech, factors associated with successful auditory training, relevant aspects of electric hearing and music perception, and extant evidence regarding limitations and advantages associated with parameters for music training with CI users. This informed the development of a computer-based music training program designed specifically for adult CI users. Principles and parameters for perceptual training of music, such as stimulus choice, rehabilitation approach, and motivational concerns were developed in relation to the unique auditory characteristics of adults with electric hearing. An outline of the resulting program components and the outcome measures for evaluating program effectiveness are presented. Music training can enhance the perceptual accuracy of music, but is also hypothesized to enhance several features of speech with similar processing requirements as music (e.g., pitch and timbre). However, additional evaluation of specific training parameters and the impact of music-based training on speech perception of CI users is required.

A preliminary report of music-based training for adult cochlear implant users: rationales and development

PubMed Central

Gfeller, Kate; Guthe, Emily; Driscoll, Virginia; Brown, Carolyn J.

2015-01-01

Objective This paper provides a preliminary report of a music-based training program for adult cochlear implant (CI) recipients. Included in this report are descriptions of the rationale for music-based training, factors influencing program development, and the resulting program components. Methods Prior studies describing experience-based plasticity in response to music training, auditory training for persons with hearing impairment, and music training for cochlear implant recipients were reviewed. These sources revealed rationales for using music to enhance speech, factors associated with successful auditory training, relevant aspects of electric hearing and music perception, and extant evidence regarding limitations and advantages associated with parameters for music training with CI users. This information formed the development of a computer-based music training program designed specifically for adult CI users. Results Principles and parameters for perceptual training of music, such as stimulus choice, rehabilitation approach, and motivational concerns were developed in relation to the unique auditory characteristics of adults with electric hearing. An outline of the resulting program components and the outcome measures for evaluating program effectiveness are presented. Conclusions Music training can enhance the perceptual accuracy of music, but is also hypothesized to enhance several features of speech with similar processing requirements as music (e.g., pitch and timbre). However, additional evaluation of specific training parameters and the impact of music-based training on speech perception of CI users are required. PMID:26561884

Bilateral cochlear implantation in the ferret: A novel animal model for behavioral studies

PubMed Central

Hartley, Douglas E.H.; Vongpaisal, Tara; Xu, Jin; Shepherd, Robert K.; King, Andrew J.; Isaiah, Amal

2010-01-01

Bilateral cochlear implantation has recently been introduced with the aim of improving both speech perception in background noise and sound localization. Although evidence suggests that binaural perception is possible with two cochlear implants, results in humans are variable. To explore potential contributing factors to these variable outcomes, we have developed a behavioral animal model of bilateral cochlear implantation in a novel species, the ferret. Although ferrets are ideally suited to psychophysical and physiological assessments of binaural hearing, cochlear implantation has not been previously described in this species. This paper describes the techniques of deafening with aminoglycoside administration, surgical implantation of an intracochlear array and chronic intracochlear electrical stimulation with monitoring for electrode integrity and efficacy of stimulation. Experiments have been presented elsewhere to show that the model can be used to study behavioral and electrophysiological measures of binaural hearing in chronically implanted animals. This paper demonstrates that cochlear implantation and chronic intracochlear electrical stimulation are both safe and effective in ferrets, opening up the possibility of using this model to study potential protective effects of bilateral cochlear implantation on the developing central auditory pathway. Since ferrets can be used to assess psychophysical and physiological aspects of hearing along with the structure of the auditory pathway in the same animals, we anticipate that this model will help develop novel neuroprosthetic therapies for use in humans. PMID:20576507

Therapy of hearing disorders - conservative procedures

PubMed Central

Plontke, Stefan

2005-01-01

A wide range of therapeutic strategies are available for the therapy of hearing disorders including pharmaceutical, acoustic, electrical, surgical, radiological, cognitive-behavioural and so-called "alternative" strategies. This review focuses on general conservative strategies and specific therapeutic approaches mainly for inner ear disorders, whereas surgical and device-based therapies including hearing aids and cochlear implants are described in other chapters in this volume. In addition to the systemic medication-based therapies for the treatment of hearing disorders, the rapidly growing field of local drug delivery to the inner ear as a promising therapeutic strategy is discussed on the background of unresolved issues. After description of non-drug-based therapeutic procedures, the conservative therapy of specific diseases and syndromes is reviewed. In general, there is a major discrepancy between promising animal studies up to regeneration and stem-cell transplantation, and uncontrolled experimental studies in humans on the one hand and the shortage of randomized controlled clinical trials with a high level of evidence on the other hand. Therefore, the review and comments on published clinical studies should assist the reader in making his/her own decision about the effectiveness of various, especially pharmaceutical treatments. From a critical analysis - particularly of the clinical studies presented - conclusions are drawn for the therapy of hearing disorders in the future. PMID:22073049

Strategy towards independent electrical stimulation from cochlear implants: Guided auditory neuron growth on topographically modified nanocrystalline diamond.

PubMed

Cai, Yixiao; Edin, Fredrik; Jin, Zhe; Alexsson, Andrei; Gudjonsson, Olafur; Liu, Wei; Rask-Andersen, Helge; Karlsson, Mikael; Li, Hao

2016-02-01

Cochlear implants (CI) have been used for several decades to treat patients with profound hearing loss. Nevertheless, results vary between individuals, and fine hearing is generally poor due to the lack of discrete neural stimulation from the individual receptor hair cells. A major problem is the deliverance of independent stimulation signals to individual auditory neurons. Fine hearing requires significantly more stimulation contacts with intimate neuron/electrode interphases from ordered axonal re-growth, something current CI technology cannot provide. Here, we demonstrate the potential application of micro-textured nanocrystalline diamond (NCD) surfaces on CI electrode arrays. Such textured NCD surfaces consist of micrometer-sized nail-head-shaped pillars (size 5×5μm(2)) made with sequences of micro/nano-fabrication processes, including sputtering, photolithography and plasma etching. The results show that human and murine inner-ear ganglion neurites and, potentially, neural progenitor cells can attach to patterned NCD surfaces without an extracellular matrix coating. Microscopic methods revealed adhesion and neural growth, specifically along the nail-head-shaped NCD pillars in an ordered manner, rather than in non-textured areas. This pattern was established when the inter-NCD pillar distance varied between 4 and 9μm. The findings demonstrate that regenerating auditory neurons show a strong affinity to the NCD pillars, and the technique could be used for neural guidance and the creation of new neural networks. Together with the NCD's unique anti-bacterial and electrical properties, patterned NCD surfaces could provide designed neural/electrode interfaces to create independent electrical stimulation signals in CI electrode arrays for the neural population. Cochlear implant is currently a successful way to treat sensorineural hearing loss and deafness especially in children. Although clinically successful, patients' fine hearing cannot be completely restored. One problem is the amount of the electrodes; 12-20 electrodes are used to replace the function of 3400 inner hair cells. Intense research is ongoing aiming to increase the number of electrodes. This study demonstrates the use of nanocrystalline diamond as a potential nerve-electrode interface. Micrometer-sized nanocrystalline diamond pillars showed high affinity to regenerated human neurons, which grew into a pre-defined network based on the pillar design. Our findings are of particular interest since they can be applied on any silicon-based implant to increase electrode count and to achieve individual neuron stimulation patterns. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Binaural release from masking with single- and multi-electrode stimulation in children with cochlear implantsa)

PubMed Central

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

2016-01-01

Cochlear implants (CIs) provide children with access to speech information from a young age. Despite bilateral cochlear implantation becoming common, use of spatial cues in free field is smaller than in normal-hearing children. Clinically fit CIs are not synchronized across the ears; thus binaural experiments must utilize research processors that can control binaural cues with precision. Research to date has used single pairs of electrodes, which is insufficient for representing speech. Little is known about how children with bilateral CIs process binaural information with multi-electrode stimulation. Toward the goal of improving binaural unmasking of speech, this study evaluated binaural unmasking with multi- and single-electrode stimulation. Results showed that performance with multi-electrode stimulation was similar to the best performance with single-electrode stimulation. This was similar to the pattern of performance shown by normal-hearing adults when presented an acoustic CI simulation. Diotic and dichotic signal detection thresholds of the children with CIs were similar to those of normal-hearing children listening to a CI simulation. The magnitude of binaural unmasking was not related to whether the children with CIs had good interaural time difference sensitivity. Results support the potential for benefits from binaural hearing and speech unmasking in children with bilateral CIs. PMID:27475132

Binaural release from masking with single- and multi-electrode stimulation in children with cochlear implants.

PubMed

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

2016-07-01

Cochlear implants (CIs) provide children with access to speech information from a young age. Despite bilateral cochlear implantation becoming common, use of spatial cues in free field is smaller than in normal-hearing children. Clinically fit CIs are not synchronized across the ears; thus binaural experiments must utilize research processors that can control binaural cues with precision. Research to date has used single pairs of electrodes, which is insufficient for representing speech. Little is known about how children with bilateral CIs process binaural information with multi-electrode stimulation. Toward the goal of improving binaural unmasking of speech, this study evaluated binaural unmasking with multi- and single-electrode stimulation. Results showed that performance with multi-electrode stimulation was similar to the best performance with single-electrode stimulation. This was similar to the pattern of performance shown by normal-hearing adults when presented an acoustic CI simulation. Diotic and dichotic signal detection thresholds of the children with CIs were similar to those of normal-hearing children listening to a CI simulation. The magnitude of binaural unmasking was not related to whether the children with CIs had good interaural time difference sensitivity. Results support the potential for benefits from binaural hearing and speech unmasking in children with bilateral CIs.

The benefits of hearing aids and closed captioning for television viewing by older adults with hearing loss

PubMed Central

Gordon-Salant, Sandra; Callahan, Julia S.

2010-01-01

Objectives Although watching television is a common leisure activity of older adults, the ability to understand televised speech may be compromised by age-related hearing loss. Two potential assistive devices for improving television viewing are hearing aids and closed captioning, but their use and benefit by older adults with hearing loss are unknown. The primary purpose of this initial investigation was to determine if older hearing-impaired adults show improvements in understanding televised speech with the use of these two assistive devices (hearing aids and closed captioning) compared to conditions without these devices. A secondary purpose was to examine the frequency of hearing aid use and closed captioning use among a sample of older hearing aid wearers. Design The investigation entailed a randomized, repeated-measures design of 15 older adults (59–82 years) with bilateral sensorineural hearing losses who wore hearing aids. Participants viewed three types of televised programs (news, drama, game show) that were each edited into lists of speech segments, and provided an identification response. Each participant was tested in four conditions: baseline (no hearing aids or closed captioning), hearing aids only, closed captioning only, and hearing aids + closed captioning. Pilot testing with young normal-hearing listeners was conducted also to establish list equivalence and stimulus intelligibility with a control group. All testing was conducted in a quiet room to simulate a living room, using a 19-in flat screen television. Questionnaires were also administered to participants to determine frequency of hearing aid use and closed captioning use while watching television. Results A significant effect of viewing condition was observed for all programs. Participants exhibited significantly better speech recognition scores in conditions with closed captioning than those without closed captioning (p<.01). Use of personal hearing aids did not significantly improve recognition of televised speech compared to the unaided condition. The condition effect was similar across the three different programs. Most of the participants (73%) regularly wore their hearing aids while watching television; very few of them (13%) had ever used closed captioning. Conclusions On average, use of closed captioning while watching television dramatically improved speech understanding by a sample of older hearing-impaired adults compared to conditions without closed captioning, including when hearing aids were worn. PMID:19444122

The Case of the Missing Pronouns: Does Mentally Simulated Perspective Play a Functional Role in the Comprehension of Person?

ERIC Educational Resources Information Center

Sato, Manami; Bergen, Benjamin K.

2013-01-01

Language comprehenders can mentally simulate perceptual and motor features of scenes they hear or read about (Barsalou, 1999; Glenberg & Kaschak, 2002; Zwaan, Stanfield, & Yaxley, 2002). Recent research shows that these simulations adopt a particular perspective (Borghi, Glenberg & Kaschak, 2004; Brunye, Ditman, Mahoney, Augustyn, & Taylor, 2009).…

Artistic understanding as embodied simulation.

PubMed

Gibbs, Raymond W

2013-04-01

Bullot & Reber (B&R) correctly include historical perspectives into the scientific study of art appreciation. But artistic understanding always emerges from embodied simulation processes that incorporate the ongoing dynamics of brains, bodies, and world interactions. There may not be separate modes of artistic understanding, but a continuum of processes that provide imaginative simulations of the artworks we see or hear.

Toward a Nonspeech Test of Auditory Cognition: Semantic Context Effects in Environmental Sound Identification in Adults of Varying Age and Hearing Abilities

PubMed Central

Sheft, Stanley; Norris, Molly; Spanos, George; Radasevich, Katherine; Formsma, Paige; Gygi, Brian

2016-01-01

Objective Sounds in everyday environments tend to follow one another as events unfold over time. The tacit knowledge of contextual relationships among environmental sounds can influence their perception. We examined the effect of semantic context on the identification of sequences of environmental sounds by adults of varying age and hearing abilities, with an aim to develop a nonspeech test of auditory cognition. Method The familiar environmental sound test (FEST) consisted of 25 individual sounds arranged into ten five-sound sequences: five contextually coherent and five incoherent. After hearing each sequence, listeners identified each sound and arranged them in the presentation order. FEST was administered to young normal-hearing, middle-to-older normal-hearing, and middle-to-older hearing-impaired adults (Experiment 1), and to postlingual cochlear-implant users and young normal-hearing adults tested through vocoder-simulated implants (Experiment 2). Results FEST scores revealed a strong positive effect of semantic context in all listener groups, with young normal-hearing listeners outperforming other groups. FEST scores also correlated with other measures of cognitive ability, and for CI users, with the intelligibility of speech-in-noise. Conclusions Being sensitive to semantic context effects, FEST can serve as a nonspeech test of auditory cognition for diverse listener populations to assess and potentially improve everyday listening skills. PMID:27893791

Analytical and numerical modeling of the hearing system: Advances towards the assessment of hearing damage.

PubMed

De Paolis, Annalisa; Bikson, Marom; Nelson, Jeremy T; de Ru, J Alexander; Packer, Mark; Cardoso, Luis

2017-06-01

Hearing is an extremely complex phenomenon, involving a large number of interrelated variables that are difficult to measure in vivo. In order to investigate such process under simplified and well-controlled conditions, models of sound transmission have been developed through many decades of research. The value of modeling the hearing system is not only to explain the normal function of the hearing system and account for experimental and clinical observations, but to simulate a variety of pathological conditions that lead to hearing damage and hearing loss, as well as for development of auditory implants, effective ear protections and auditory hazard countermeasures. In this paper, we provide a review of the strategies used to model the auditory function of the external, middle, inner ear, and the micromechanics of the organ of Corti, along with some of the key results obtained from such modeling efforts. Recent analytical and numerical approaches have incorporated the nonlinear behavior of some parameters and structures into their models. Few models of the integrated hearing system exist; in particular, we describe the evolution of the Auditory Hazard Assessment Algorithm for Human (AHAAH) model, used for prediction of hearing damage due to high intensity sound pressure. Unlike the AHAAH model, 3D finite element models of the entire hearing system are not able yet to predict auditory risk and threshold shifts. It is expected that both AHAAH and FE models will evolve towards a more accurate assessment of threshold shifts and hearing loss under a variety of stimuli conditions and pathologies. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Constrained inference in mixed-effects models for longitudinal data with application to hearing loss.

PubMed

Davidov, Ori; Rosen, Sophia

2011-04-01

In medical studies, endpoints are often measured for each patient longitudinally. The mixed-effects model has been a useful tool for the analysis of such data. There are situations in which the parameters of the model are subject to some restrictions or constraints. For example, in hearing loss studies, we expect hearing to deteriorate with time. This means that hearing thresholds which reflect hearing acuity will, on average, increase over time. Therefore, the regression coefficients associated with the mean effect of time on hearing ability will be constrained. Such constraints should be accounted for in the analysis. We propose maximum likelihood estimation procedures, based on the expectation-conditional maximization either algorithm, to estimate the parameters of the model while accounting for the constraints on them. The proposed methods improve, in terms of mean square error, on the unconstrained estimators. In some settings, the improvement may be substantial. Hypotheses testing procedures that incorporate the constraints are developed. Specifically, likelihood ratio, Wald, and score tests are proposed and investigated. Their empirical significance levels and power are studied using simulations. It is shown that incorporating the constraints improves the mean squared error of the estimates and the power of the tests. These improvements may be substantial. The methodology is used to analyze a hearing loss study.

Experience Changes How Emotion in Music Is Judged: Evidence from Children Listening with Bilateral Cochlear Implants, Bimodal Devices, and Normal Hearing

PubMed Central

Papsin, Blake C.; Paludetti, Gaetano; Gordon, Karen A.

2015-01-01

Children using unilateral cochlear implants abnormally rely on tempo rather than mode cues to distinguish whether a musical piece is happy or sad. This led us to question how this judgment is affected by the type of experience in early auditory development. We hypothesized that judgments of the emotional content of music would vary by the type and duration of access to sound in early life due to deafness, altered perception of musical cues through new ways of using auditory prostheses bilaterally, and formal music training during childhood. Seventy-five participants completed the Montreal Emotion Identification Test. Thirty-three had normal hearing (aged 6.6 to 40.0 years) and 42 children had hearing loss and used bilateral auditory prostheses (31 bilaterally implanted and 11 unilaterally implanted with contralateral hearing aid use). Reaction time and accuracy were measured. Accurate judgment of emotion in music was achieved across ages and musical experience. Musical training accentuated the reliance on mode cues which developed with age in the normal hearing group. Degrading pitch cues through cochlear implant-mediated hearing induced greater reliance on tempo cues, but mode cues grew in salience when at least partial acoustic information was available through some residual hearing in the contralateral ear. Finally, when pitch cues were experimentally distorted to represent cochlear implant hearing, individuals with normal hearing (including those with musical training) switched to an abnormal dependence on tempo cues. The data indicate that, in a western culture, access to acoustic hearing in early life promotes a preference for mode rather than tempo cues which is enhanced by musical training. The challenge to these preferred strategies during cochlear implant hearing (simulated and real), regardless of musical training, suggests that access to pitch cues for children with hearing loss must be improved by preservation of residual hearing and improvements in cochlear implant technology. PMID:26317976

Experience Changes How Emotion in Music Is Judged: Evidence from Children Listening with Bilateral Cochlear Implants, Bimodal Devices, and Normal Hearing.

PubMed

Giannantonio, Sara; Polonenko, Melissa J; Papsin, Blake C; Paludetti, Gaetano; Gordon, Karen A

2015-01-01

Children using unilateral cochlear implants abnormally rely on tempo rather than mode cues to distinguish whether a musical piece is happy or sad. This led us to question how this judgment is affected by the type of experience in early auditory development. We hypothesized that judgments of the emotional content of music would vary by the type and duration of access to sound in early life due to deafness, altered perception of musical cues through new ways of using auditory prostheses bilaterally, and formal music training during childhood. Seventy-five participants completed the Montreal Emotion Identification Test. Thirty-three had normal hearing (aged 6.6 to 40.0 years) and 42 children had hearing loss and used bilateral auditory prostheses (31 bilaterally implanted and 11 unilaterally implanted with contralateral hearing aid use). Reaction time and accuracy were measured. Accurate judgment of emotion in music was achieved across ages and musical experience. Musical training accentuated the reliance on mode cues which developed with age in the normal hearing group. Degrading pitch cues through cochlear implant-mediated hearing induced greater reliance on tempo cues, but mode cues grew in salience when at least partial acoustic information was available through some residual hearing in the contralateral ear. Finally, when pitch cues were experimentally distorted to represent cochlear implant hearing, individuals with normal hearing (including those with musical training) switched to an abnormal dependence on tempo cues. The data indicate that, in a western culture, access to acoustic hearing in early life promotes a preference for mode rather than tempo cues which is enhanced by musical training. The challenge to these preferred strategies during cochlear implant hearing (simulated and real), regardless of musical training, suggests that access to pitch cues for children with hearing loss must be improved by preservation of residual hearing and improvements in cochlear implant technology.

Improving Balance Function Using Low Levels of Electrical Stimulation of the Balance Organs

NASA Technical Reports Server (NTRS)

Bloomberg, Jacob; Reschke, Millard; Mulavara, Ajitkumar; Wood, Scott; Serrador, Jorge; Fiedler, Matthew; Kofman, Igor; Peters, Brian T.; Cohen, Helen

2012-01-01

Crewmembers returning from long-duration space flight face significant challenges due to the microgravity-induced inappropriate adaptations in balance/ sensorimotor function. The Neuroscience Laboratory at JSC is developing a method based on stochastic resonance to enhance the brain s ability to detect signals from the balance organs of the inner ear and use them for rapid improvement in balance skill, especially when combined with balance training exercises. This method involves a stimulus delivery system that is wearable/portable providing imperceptible electrical stimulation to the balance organs of the human body. Stochastic resonance (SR) is a phenomenon whereby the response of a nonlinear system to a weak periodic input signal is optimized by the presence of a particular non-zero level of noise. This phenomenon of SR is based on the concept of maximizing the flow of information through a system by a non-zero level of noise. Application of imperceptible SR noise coupled with sensory input in humans has been shown to improve motor, cardiovascular, visual, hearing, and balance functions. SR increases contrast sensitivity and luminance detection; lowers the absolute threshold for tone detection in normal hearing individuals; improves homeostatic function in the human blood pressure regulatory system; improves noise-enhanced muscle spindle function; and improves detection of weak tactile stimuli using mechanical or electrical stimulation. SR noise has been shown to improve postural control when applied as mechanical noise to the soles of the feet, or when applied as electrical noise at the knee and to the back muscles.

76 FR 50767 - Southern Nuclear Operating Co., et al.; Combined Licenses for Vogtle Electric Generating Plant...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-16

... Limited Work Authorizations AGENCY: Nuclear Regulatory Commission. ACTION: Notice of hearing. SUMMARY: The... Southern Nuclear Operating Company for two combined licenses (COLs) seeking approval to construct and...), as well as for two limited work authorizations (LWAs) to engage in selected construction activities...

Developmental Exposure to an Environmental PCB Mixture Delays the Propagation of Kindling in the Amygdala

EPA Science Inventory

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 eva...

APPLIED AUDIOLOGY FOR CHILDREN. SECOND EDITION.

ERIC Educational Resources Information Center

DALE, D.M.C.

THE PURPOSE OF THE BOOK IS TO HELP TEACHERS, PARENTS, DOCTORS, AND WORKERS IN AUDIOLOGY CLINICS MAKE THE MOST OF SOUND IN THE EDUCATIONAL AND SOCIAL TREATMENT OF DEAFNESS. ASPECTS OF SOUND AMPLIFICATION CONSIDERED ARE THE NATURE OF SOUND, ELECTRICAL AMPLIFICATION, AND VARIOUS TYPES OF HEARING AIDS (INDIVIDUAL, GROUP, INDUCTION LOOP, SPEECH…

Bush reversal of CO2 pledge draws heated reaction

NASA Astrophysics Data System (ADS)

Showstack, Randy

Chairing a march 14 hearing of the House of Representatives Science Committee on the science of global warning, U.S. congressman Sherwood Boehlert (R-N.Y.) commented on President George W. Bush's reversal the previouse day of a campaign pldege to regulate carbon dioxide from electric power generating plants.

Identification and Multiplicity of Double Vowels in Cochlear Implant Users

ERIC Educational Resources Information Center

Kwon, Bomjun J.; Perry, Trevor T.

2014-01-01

Purpose: The present study examined cochlear implant (CI) users' perception of vowels presented concurrently (i.e., "double vowels") to further our understanding of auditory grouping in electric hearing. Method: Identification of double vowels and single vowels was measured with 10 CI subjects. Fundamental frequencies (F0s) of…

Simulation of Rocket-Grade Kerosene Flowing in an Electrically Heated Experimental Apparatus

DTIC Science & Technology

2015-07-01

Technical Paper 3. DATES COVERED (From - To) July 2015-July 2015 4. TITLE AND SUBTITLE Simulation of Rocket Kerosene Flowing in an Electrically Heated...rocket-grade kerosene (RP-2) flowing in an electrically heated tube is simulated. The model and boundary conditions are selected so as to simulate an...and Astronautics 1 Simulation of Rocket-Grade Kerosene Flowing in an Electrically Heated Experimental Apparatus Ananda Himansu1 and Matthew C

Multicenter Clinical Trial of the Nucleus® Hybrid™ S8 Cochlear Implant: Final Outcomes

PubMed Central

Gantz, Bruce J; Dunn, Camille; Oleson, Jacob; Hansen, Marlan; Parkinson, Aaron; Turner, Christopher

2015-01-01

Objective The concept expanding electrical speech processing to those with more residual acoustic hearing with a less invasive shorter cochlear implant has been ongoing since 1999. A multi-center study of the Nucleus Hybrid S8 CI took place between 2002–11. This report describes the final outcomes of this clinical trial. Study Design Multi-Center longitudinal single subject design Methods Eighty-seven subjects received a Nucleus® Hybrid™ S8 implant in their poorer ear. Speech perception in quiet (CNC words) and in noise (BKB-SIN) was collected pre- and post-operatively at 3, 6, and 12 months. Subjective questionnaire data using the APHAB was also collected. Results Some level of hearing preservation was accomplished in 98% subjects with 90% maintaining a functional low-frequency pure-tone average (LFPTA) at initial activation. By 12 months, 5 subjects had total hearing loss and 80% of subjects maintained functional hearing. CNC words demonstrated that 82.5% and 87.5% of subjects had significant improvements in the Hybrid and Combined conditions. The majority of had improvements with BKB-SIN. Results also indicated that as long as subjects maintained at least a severe LFPTA, there was significant improvement in speech understanding. Furthermore, all subjects reported positive improvements in hearing in three of the 4 subscales of the APHAB. Conclusion The concept of hybrid speech processing has significant advantages for subjects with residual low-frequency hearing. In this study, the Nucleus® Hybrid™ S8 provided improved word understanding in quiet and noise. Additionally, there appears to be stability of the residual hearing after initial activation of the device. Level of evidence 2c PMID:26756395

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

How close should a student with unilateral hearing loss stay to a teacher in a noisy classroom?

PubMed

Noh, Heil; Park, Yong-Gyu

2012-06-01

To determine the optimal seating position in a noisy classroom for students with unilateral hearing loss (UHL) without any auditory rehabilitation as compared to normal-hearing adults and student peers. Speech discrimination scores (SDS) for babble noise at distances of 3, 4, 6, 8, and 10 m from a speaker were measured in a simulated classroom measuring 300 m3 (reverberation time = 0.43 s). Students with UHL (n = 25, 10-19 years old), normal-hearing students (n = 25), and normal-hearing adults (n = 25). The SDS for the normal-hearing adults at the 3, 4, 6, 8, and 10 m distances were 90.0±6.4%, 84.7±7.9%, 80.6±10.0%, 75.5±12.6%, and 68.8±13.0%, respectively. Those for the normal-hearing students were 90.1±6.2%, 78.1±9.4%, 66.4±10.7%, 61.8±11.2%, and 60.8±10.9%. Those for the UHL group were 81.7±9.0%, 70.2±12.4%, 62.1±17.2%, 52.4±17.1%, and 48.9±17.9%. The UHL group needed a seating position of 4.35 m to achieve an equivalent mean SDS as those for normal-hearing adults seated at 10 m. Likewise, the UHL group needed to be seated at 6.27 m to have an equivalent SDS as the normal-hearing students seated at 10 m. Students with UHL in noisy classrooms require seating ranging from 4.35 m to no further than 6.27 m away from a teacher to obtain a SDS comparable to normal hearing adults and student peers.

Optimizing the Combination of Acoustic and Electric Hearing in the Implanted Ear

PubMed Central

Karsten, Sue A.; Turner, Christopher W.; Brown, Carolyn J.; Jeon, Eun Kyung; Abbas, Paul J.; Gantz, Bruce J.

2016-01-01

Objectives The aim of this study was to determine an optimal approach to program combined acoustic plus electric (A+E) hearing devices in the same ear to maximize speech-recognition performance. Design Ten participants with at least 1 year of experience using Nucleus Hybrid (short electrode) A+E devices were evaluated across three different fitting conditions that varied in the frequency ranges assigned to the acoustically and electrically presented portions of the spectrum. Real-ear measurements were used to optimize the acoustic component for each participant, and the acoustic stimulation was then held constant across conditions. The lower boundary of the electric frequency range was systematically varied to create three conditions with respect to the upper boundary of the acoustic spectrum: Meet, Overlap, and Gap programming. Consonant recognition in quiet and speech recognition in competing-talker babble were evaluated after participants were given the opportunity to adapt by using the experimental programs in their typical everyday listening situations. Participants provided subjective ratings and evaluations for each fitting condition. Results There were no significant differences in performance between conditions (Meet, Overlap, Gap) for consonant recognition in quiet. A significant decrement in performance was measured for the Overlap fitting condition for speech recognition in babble. Subjective ratings indicated a significant preference for the Meet fitting regimen. Conclusions Participants using the Hybrid ipsilateral A+E device generally performed better when the acoustic and electric spectra were programmed to meet at a single frequency region, as opposed to a gap or overlap. Although there is no particular advantage for the Meet fitting strategy for recognition of consonants in quiet, the advantage becomes evident for speech recognition in competing-talker babble and in patient preferences. PMID:23059851

Tolerable hearing-aid delays: IV. effects on subjective disturbance during speech production by hearing-impaired subjects.

PubMed

Stone, Michael A; Moore, Brian C J

2005-04-01

We assessed the effects of time delay in a hearing aid on subjective disturbance and reading rates while the user of the aid was speaking, using hearing-impaired subjects and real-time processing. The time delay was constant across frequency. A digital signal processor was programmed as a four-channel, fast-acting, wide-dynamic-range compression hearing aid. One of four delays could be selected on the aid to produce a total delay of 13, 21, 30, or 40 msec between microphone and receiver. Twenty-five subjects, mostly with near-symmetric hearing impairment of cochlear origin, were fitted bilaterally with behind-the-ear aids connected to the processor. The aids were programmed with insertion gains prescribed by the CAMEQ loudness equalization procedure for each subject and ear. Subjects were asked to read aloud from scripts: speech production rates were measured and subjective ratings of the disturbance of the delay were obtained. Subjects required some training to recognize the effects of the delay to rate it consistently. Subjective disturbance increased progressively with increasing delay and was a nonmonotonic function of low-frequency hearing loss. Subjects with mild or severe low-frequency hearing loss were generally less disturbed by the delay than those with moderate loss. Disturbance ratings tended to decrease over successive tests. Word production rates were not significantly affected by delay over the range of delays tested. The results follow a pattern similar to those presented in , obtained using a simulation of hearing loss and normally hearing subjects, except for the nonmonotonic variation of disturbance with low-frequency hearing loss. We hypothesize that disturbance is maximal when the levels in the ear canal of the low-frequency components are similar for the unaided and aided sounds. A rating of 3, which is probably just acceptable, was obtained for delays ranging from 14 to 30 msec, depending on the hearing loss. Some acclimatization to the subjective disturbance occurred over a time scale of about 1 hour.

Simulation of bone-conducted sound transmission in a three-dimensional finite-element model of a human skull

NASA Astrophysics Data System (ADS)

Chang, You; Kim, Namkeun; Stenfelt, Stefan

2015-12-01

Bone conduction (BC) is the transmission of sound to the inner ear through the bones of the skull. This type of transmission is used in humans fitted with BC hearing aids as well as to classify between conductive and sensorineural hearing losses. The objective of the present study is to develop a finite-element (FE) model of the human skull based on cryosectional images of a female cadaver head in order to gain better understanding of the sound transmission. Further, the BC behavior was validated in terms of sound transmission against experimental data published in the literature. Results showed the responses of the simulated skull FE model were consistent with the experimentally reported data.

An electric scooter simulation program for training the driving skills of stroke patients with mobility problems: a pilot study.

PubMed

Jannink, Michiel J A; Erren-Wolters, C Victorien; de Kort, Alexander C; van der Kooij, Herman

2008-12-01

This paper describes an electric scooter simulation program and a first evaluation study in which we explored if it is possible to train the driving skills of future users of electric mobility scooters by means of an electric scooter simulation program in addition to conventional electric scooter training. Within this explorative study,10 stroke survivors were randomly assigned to either the control (n=5) or the electric scooter simulation intervention group (n=5). Participants were assessed twice on the functional evaluating rating scale. During the followup measurement, subjective experiences regarding both forms of electric scooter training were elicited by a questionnaire. After a training period of 5 weeks, both groups improved on the Functional Evaluation Rating Scale. It can be concluded that the patients with stroke were satisfied with the electric scooter simulation training.

2-dimensional simulations of electrically asymmetric capacitively coupled RF-discharges

NASA Astrophysics Data System (ADS)

Mohr, Sebastian; Schulze, Julian; Schuengel, Edmund; Czarnetzki, Uwe

2011-10-01

Capactively coupled RF-discharges are widely used for surface treatment like the deposition of thin films. For industrial applications, the independent control of the ion flux to and the mean energy of the electrons impinging on the surfaces is desired. Experiments and 1D3v-PIC/MCC-simulations have shown that this independent control is possible by applying a fundamental frequency and its second harmonic to the powered electrode. This way, even in geometrically symmetric discharges, as they are often used in industrial reactors, a discharge asymmetry can be induced electrically, hence the name Electrical Asymmetry Effect (EAE). We performed 2D-simulations of electrically asymmetric discharges using HPEM by the group of Mark Kushner, a simulation tool suitable for simulating industrial reactors. First results are presented and compared to previously obtained experimental and simulation data. The comparison shows that for the first time, we succeeded in simulating electrically asymmetric discharges with a 2-dimensional simulation. Capactively coupled RF-discharges are widely used for surface treatment like the deposition of thin films. For industrial applications, the independent control of the ion flux to and the mean energy of the electrons impinging on the surfaces is desired. Experiments and 1D3v-PIC/MCC-simulations have shown that this independent control is possible by applying a fundamental frequency and its second harmonic to the powered electrode. This way, even in geometrically symmetric discharges, as they are often used in industrial reactors, a discharge asymmetry can be induced electrically, hence the name Electrical Asymmetry Effect (EAE). We performed 2D-simulations of electrically asymmetric discharges using HPEM by the group of Mark Kushner, a simulation tool suitable for simulating industrial reactors. First results are presented and compared to previously obtained experimental and simulation data. The comparison shows that for the first time, we succeeded in simulating electrically asymmetric discharges with a 2-dimensional simulation. Funding: German Ministry for the Environment (0325210B).

Child implant users' imitation of happy- and sad-sounding speech

PubMed Central

Wang, David J.; Trehub, Sandra E.; Volkova, Anna; van Lieshout, Pascal

2013-01-01

Cochlear implants have enabled many congenitally or prelingually deaf children to acquire their native language and communicate successfully on the basis of electrical rather than acoustic input. Nevertheless, degraded spectral input provided by the device reduces the ability to perceive emotion in speech. We compared the vocal imitations of 5- to 7-year-old deaf children who were highly successful bilateral implant users with those of a control sample of children who had normal hearing. First, the children imitated several happy and sad sentences produced by a child model. When adults in Experiment 1 rated the similarity of imitated to model utterances, ratings were significantly higher for the hearing children. Both hearing and deaf children produced poorer imitations of happy than sad utterances because of difficulty matching the greater pitch modulation of the happy versions. When adults in Experiment 2 rated electronically filtered versions of the utterances, which obscured the verbal content, ratings of happy and sad utterances were significantly differentiated for deaf as well as hearing children. The ratings of deaf children, however, were significantly less differentiated. Although deaf children's utterances exhibited culturally typical pitch modulation, their pitch modulation was reduced relative to that of hearing children. One practical implication is that therapeutic interventions for deaf children could expand their focus on suprasegmental aspects of speech perception and production, especially intonation patterns. PMID:23801976

The role of spectral and temporal cues in voice gender discrimination by normal-hearing listeners and cochlear implant users.

PubMed

Fu, Qian-Jie; Chinchilla, Sherol; Galvin, John J

2004-09-01

The present study investigated the relative importance of temporal and spectral cues in voice gender discrimination and vowel recognition by normal-hearing subjects listening to an acoustic simulation of cochlear implant speech processing and by cochlear implant users. In the simulation, the number of speech processing channels ranged from 4 to 32, thereby varying the spectral resolution; the cutoff frequencies of the channels' envelope filters ranged from 20 to 320 Hz, thereby manipulating the available temporal cues. For normal-hearing subjects, results showed that both voice gender discrimination and vowel recognition scores improved as the number of spectral channels was increased. When only 4 spectral channels were available, voice gender discrimination significantly improved as the envelope filter cutoff frequency was increased from 20 to 320 Hz. For all spectral conditions, increasing the amount of temporal information had no significant effect on vowel recognition. Both voice gender discrimination and vowel recognition scores were highly variable among implant users. The performance of cochlear implant listeners was similar to that of normal-hearing subjects listening to comparable speech processing (4-8 spectral channels). The results suggest that both spectral and temporal cues contribute to voice gender discrimination and that temporal cues are especially important for cochlear implant users to identify the voice gender when there is reduced spectral resolution.

Data on evolutionary relationships between hearing reduction with history of disease and injuries among workers in Abadan Petroleum Refinery, Iran.

PubMed

Mohammadi, Mohammad Javad; Ghazlavi, Ebtesam; Gamizji, Samira Rashidi; Sharifi, Hajar; Gamizji, Fereshteh Rashidi; Zahedi, Atefeh; Geravandi, Sahar; Tahery, Noorollah; Yari, Ahmad Reza; Momtazan, Mahboobeh

2018-02-01

The present work examined data obtained during the analysis of Hearing Reduction (HR) of Abadan Petroleum Refinery (Abadan PR) workers of Iran with a history of disease and injuries. To this end, all workers in the refinery were chosen. In this research, the effects of history of disease and injury including trauma, electric shock, meningitis-typhoid disease and genetic illness as well as contact with lead, mercury, CO 2 and alcohol consumption were evaluated (Lie, et al., 2016) [1]. After the completion of the questionnaires by workers, the coded data were fed into EXCELL. Statistical analysis of data was carried out, using SPSS 16.

Usher proteins in inner ear structure and function.

PubMed

Ahmed, Zubair M; Frolenkov, Gregory I; Riazuddin, Saima

2013-11-01

Usher syndrome (USH) is a neurosensory disorder affecting both hearing and vision in humans. Linkage studies of families of USH patients, studies in animals, and characterization of purified proteins have provided insight into the molecular mechanisms of hearing. To date, 11 USH proteins have been identified, and evidence suggests that all of them are crucial for the function of the mechanosensory cells of the inner ear, the hair cells. Most USH proteins are localized to the stereocilia of the hair cells, where mechano-electrical transduction (MET) of sound-induced vibrations occurs. Therefore, elucidation of the functions of USH proteins in the stereocilia is a prerequisite to understanding the exact mechanisms of MET.

A Comprehensive Study on the Etiology of Patients Receiving Cochlear Implantation With Special Emphasis on Genetic Epidemiology

PubMed Central

Miyagawa, Maiko; Nishio, Shin-Ya; Usami, Shin-Ichi

2016-01-01

Objective: Cochlear implantation is the most important treatment currently available for profound sensorineural hearing loss. The aim of this study was to investigate the etiology of hearing loss in patients with cochlear implantation, and to compare outcomes. Methods: Japanese hearing loss patients who received cochlear implants (CIs) or electric acoustic stimulation (EAS) in Shinshu University hospital (n = 173, prelingual onset: 92, postlingual onset: 81) participated in this study. Invader assay followed by the targeted exon-sequencing of 63 deafness genes using Massively parallel DNA sequencing (MPS) was applied. For prelingual patients, additional imaging examination, cCMV screening, and pediatric examination were performed for precise diagnosis. Results: Genetic screening successfully identified the causative mutation in 60% of patients with prelingual onset hearing loss and in 36% of those with postlingual hearing loss. Differences in the kinds of genes identified were observed between the two groups. Although there were marked variations in the outcome of cochlear implantation, patients with specific deafness gene mutations showed relatively good results. Conclusion: The present study showed genetic etiology is a major cause of hearing loss in CI/EAS patients. Patients possessing mutations in a number of deafness genes known to be expressed within inner ear have achieved satisfactory auditory performance, suggesting that the identification of the genetic background facilitates the prediction of post-CI performance. MPS is a powerful tool for the identification of causative deafness genes in patients receiving cochlear implantation. Therefore, determination of the involved region inside/outside of the cochlea by identification of the responsible gene is essential. PMID:26756145

Using ILD or ITD Cues for Sound Source Localization and Speech Understanding in a Complex Listening Environment by Listeners With Bilateral and With Hearing-Preservation Cochlear Implants.

PubMed

Loiselle, Louise H; Dorman, Michael F; Yost, William A; Cook, Sarah J; Gifford, Rene H

2016-08-01

To assess the role of interaural time differences and interaural level differences in (a) sound-source localization, and (b) speech understanding in a cocktail party listening environment for listeners with bilateral cochlear implants (CIs) and for listeners with hearing-preservation CIs. Eleven bilateral listeners with MED-EL (Durham, NC) CIs and 8 listeners with hearing-preservation CIs with symmetrical low frequency, acoustic hearing using the MED-EL or Cochlear device were evaluated using 2 tests designed to task binaural hearing, localization, and a simulated cocktail party. Access to interaural cues for localization was constrained by the use of low-pass, high-pass, and wideband noise stimuli. Sound-source localization accuracy for listeners with bilateral CIs in response to the high-pass noise stimulus and sound-source localization accuracy for the listeners with hearing-preservation CIs in response to the low-pass noise stimulus did not differ significantly. Speech understanding in a cocktail party listening environment improved for all listeners when interaural cues, either interaural time difference or interaural level difference, were available. The findings of the current study indicate that similar degrees of benefit to sound-source localization and speech understanding in complex listening environments are possible with 2 very different rehabilitation strategies: the provision of bilateral CIs and the preservation of hearing.

Future technology in cochlear implants: assessing the benefit.

PubMed

Briggs, Robert J S

2011-05-01

It has been over 50 years since Djourno and Eyries first attempted electric stimulation in a patient with deafness. Over this time, the Cochlear Implant (CI) has become not only remarkably successful, but increasingly complex. Although the basic components of the system still comprise an implanted receiver stimulator and electrode, externally worn speech processor, microphone, control system, and power source, there are now several alternative designs of these components with different attributes that can be variably combined to meet the needs of specific patient groups. Development by the manufacturers has been driven both by these various patient needs, and also by the desire to achieve technological superiority, or at least differentiation, ultimately in pursuit of market share. Assessment of benefit is the responsibility of clinicians. It is incumbent on both industry and clinicians to ensure appropriate, safe, and affordable introduction of new technology. For example, experience with the totally implanted cochlear implant (TIKI) has demonstrated that quality of hearing is the over-riding consideration for CI users. To date, improved hearing outcomes have been achieved by improvements in: speech processing strategies; microphone technology; pre-processing strategies; electrode placement; bilateral implantation; use of a hearing aid in the opposite ear (bimodal stimulation); and the combination of electric and acoustic stimulation in the same ear. The resulting expansion of CI candidacy, with more residual hearing, further improves the outcomes achieved. Largely facilitated by advances in electronic capability and computerization, it can be expected that these improvements will continue. However, marked variability of results still occurs and we cannot assure any individual patient of their outcome. Realistic goals for implementation of new technology include: improved hearing in noise and music perception; effective invisible hearing (no external apparatus); automated fitting; and reduction in outcome variability. This paper provides examples of relevant potential future technologies that can be applied to reach these goals. In the quest for better outcomes, future technology must deliver improved reliability and usability for both clinicians and recipients that does not compromise safety and is affordable. One of the challenges related to the introduction of new technologies is the 'classification' of CI systems and the framework under which sufficient change and increased benefit can be demonstrated to establish a claim of 'new generation CI' and hence increased reimbursement from third-party payers. Significant improvements in hearing outcomes and quality of life associated with CI design changes are difficult to measure, particularly when there is such dramatic benefit from the intervention of cochlear implantation from the individual's perspective. Manufacturers and clinicians need to be objective and undertake appropriate safety studies and long-term and multi-centre clinical trials to ensure that the introduction of new technology is both safe and effective and supported by health systems worldwide.

Effects of Talker Variability on Vowel Recognition in Cochlear Implants

ERIC Educational Resources Information Center

Chang, Yi-ping; Fu, Qian-Jie

2006-01-01

Purpose: To investigate the effects of talker variability on vowel recognition by cochlear implant (CI) users and by normal-hearing (NH) participants listening to 4-channel acoustic CI simulations. Method: CI users were tested with their clinically assigned speech processors. For NH participants, 3 CI processors were simulated, using different…

Watergate: The Waterloo of a President. ETC Simulation Number 1.

ERIC Educational Resources Information Center

Hostrop, Richard W.

This booklet provides instructions for simulating the causes and events that led to the resignation of Richard Nixon as President of the United States. Students role-play activities related to the Watergate break-in, the cover-up attempts, the Congressional hearings relating to impeachment considerations, and the resignation of President Richard…

Listening Effort and Speech Recognition with Frequency Compression Amplification for Children and Adults with Hearing Loss.

PubMed

Brennan, Marc A; Lewis, Dawna; McCreery, Ryan; Kopun, Judy; Alexander, Joshua M

2017-10-01

Nonlinear frequency compression (NFC) can improve the audibility of high-frequency sounds by lowering them to a frequency where audibility is better; however, this lowering results in spectral distortion. Consequently, performance is a combination of the effects of increased access to high-frequency sounds and the detrimental effects of spectral distortion. Previous work has demonstrated positive benefits of NFC on speech recognition when NFC is set to improve audibility while minimizing distortion. However, the extent to which NFC impacts listening effort is not well understood, especially for children with sensorineural hearing loss (SNHL). To examine the impact of NFC on recognition and listening effort for speech in adults and children with SNHL. Within-subject, quasi-experimental study. Participants listened to amplified nonsense words that were (1) frequency-lowered using NFC, (2) low-pass filtered at 5 kHz to simulate the restricted bandwidth (RBW) of conventional hearing aid processing, or (3) low-pass filtered at 10 kHz to simulate extended bandwidth (EBW) amplification. Fourteen children (8-16 yr) and 14 adults (19-65 yr) with mild-to-severe SNHL. Participants listened to speech processed by a hearing aid simulator that amplified input signals to fit a prescriptive target fitting procedure. Participants were blinded to the type of processing. Participants' responses to each nonsense word were analyzed for accuracy and verbal-response time (VRT; listening effort). A multivariate analysis of variance and linear mixed model were used to determine the effect of hearing-aid signal processing on nonsense word recognition and VRT. Both children and adults identified the nonsense words and initial consonants better with EBW and NFC than with RBW. The type of processing did not affect the identification of the vowels or final consonants. There was no effect of age on recognition of the nonsense words, initial consonants, medial vowels, or final consonants. VRT did not change significantly with the type of processing or age. Both adults and children demonstrated improved speech recognition with access to the high-frequency sounds in speech. Listening effort as measured by VRT was not affected by access to high-frequency sounds. American Academy of Audiology

Synaptic Plasticity after Chemical Deafening and Electrical Stimulation of the Auditory Nerve in Cats

PubMed Central

Ryugo, D.K.; Baker, C.A.; Montey, K.L.; Chang, L.Y.; Coco, A.; Fallon, J.B.; Shepherd, R.K.

2010-01-01

The effects of deafness on brain structure and function have been studied using animal models of congenital deafness that include surgical ablation of the organ of Corti, acoustic trauma, ototoxic drugs, and hereditary deafness. This report describes the morphologic plasticity of auditory nerve synapses in response to ototoxic deafening and chronic electrical stimulation of the auditory nerve. Normal kittens were deafened by neonatal administration of neomycin that eliminated auditory receptor cells. Some of these cats were raised deaf, whereas others were chronically implanted with cochlear electrodes at two months of age and electrically stimulated for up to 12 months. The large endings of the auditory nerve, endbulbs of Held, were studied because they hold a key position in the timing pathway for sound localization, are readily identifiable, and exhibit deafness-associated abnormalities. Compared to normal hearing cats, synapses of ototoxically deafened cats displayed expanded postsynaptic densities, a decrease in synaptic vesicle (SV) density, and a reduction in the somatic size of spherical bushy cells (SBCs). When compared to normal hearing cats, endbulbs of ototoxically deafened cats that received cochlear stimulation expressed postsynaptic densities (PSDs) that were statistically identical in size, showed a 32.8% reduction in SV density, and whose target SBCs had a 25.5% reduction in soma area. These results demonstrate that electrical stimulation via a cochlear implant in chemically-deafened cats preserves PSD size but not other aspects of synapse morphology. The results further suggest that the effects of ototoxic deafness are not identical to those of hereditary deafness. PMID:20127807

Reference-Free Assessment of Speech Intelligibility Using Bispectrum of an Auditory Neurogram.

PubMed

Hossain, Mohammad E; Jassim, Wissam A; Zilany, Muhammad S A

2016-01-01

Sensorineural hearing loss occurs due to damage to the inner and outer hair cells of the peripheral auditory system. Hearing loss can cause decreases in audibility, dynamic range, frequency and temporal resolution of the auditory system, and all of these effects are known to affect speech intelligibility. In this study, a new reference-free speech intelligibility metric is proposed using 2-D neurograms constructed from the output of a computational model of the auditory periphery. The responses of the auditory-nerve fibers with a wide range of characteristic frequencies were simulated to construct neurograms. The features of the neurograms were extracted using third-order statistics referred to as bispectrum. The phase coupling of neurogram bispectrum provides a unique insight for the presence (or deficit) of supra-threshold nonlinearities beyond audibility for listeners with normal hearing (or hearing loss). The speech intelligibility scores predicted by the proposed method were compared to the behavioral scores for listeners with normal hearing and hearing loss both in quiet and under noisy background conditions. The results were also compared to the performance of some existing methods. The predicted results showed a good fit with a small error suggesting that the subjective scores can be estimated reliably using the proposed neural-response-based metric. The proposed metric also had a wide dynamic range, and the predicted scores were well-separated as a function of hearing loss. The proposed metric successfully captures the effects of hearing loss and supra-threshold nonlinearities on speech intelligibility. This metric could be applied to evaluate the performance of various speech-processing algorithms designed for hearing aids and cochlear implants.

Reference-Free Assessment of Speech Intelligibility Using Bispectrum of an Auditory Neurogram

PubMed Central

Hossain, Mohammad E.; Jassim, Wissam A.; Zilany, Muhammad S. A.

2016-01-01

Sensorineural hearing loss occurs due to damage to the inner and outer hair cells of the peripheral auditory system. Hearing loss can cause decreases in audibility, dynamic range, frequency and temporal resolution of the auditory system, and all of these effects are known to affect speech intelligibility. In this study, a new reference-free speech intelligibility metric is proposed using 2-D neurograms constructed from the output of a computational model of the auditory periphery. The responses of the auditory-nerve fibers with a wide range of characteristic frequencies were simulated to construct neurograms. The features of the neurograms were extracted using third-order statistics referred to as bispectrum. The phase coupling of neurogram bispectrum provides a unique insight for the presence (or deficit) of supra-threshold nonlinearities beyond audibility for listeners with normal hearing (or hearing loss). The speech intelligibility scores predicted by the proposed method were compared to the behavioral scores for listeners with normal hearing and hearing loss both in quiet and under noisy background conditions. The results were also compared to the performance of some existing methods. The predicted results showed a good fit with a small error suggesting that the subjective scores can be estimated reliably using the proposed neural-response-based metric. The proposed metric also had a wide dynamic range, and the predicted scores were well-separated as a function of hearing loss. The proposed metric successfully captures the effects of hearing loss and supra-threshold nonlinearities on speech intelligibility. This metric could be applied to evaluate the performance of various speech-processing algorithms designed for hearing aids and cochlear implants. PMID:26967160

Normal-Hearing Listeners’ and Cochlear Implant Users’ Perception of Pitch Cues in Emotional Speech

PubMed Central

Fuller, Christina; Gilbers, Dicky; Broersma, Mirjam; Goudbeek, Martijn; Free, Rolien; Başkent, Deniz

2015-01-01

In cochlear implants (CIs), acoustic speech cues, especially for pitch, are delivered in a degraded form. This study’s aim is to assess whether due to degraded pitch cues, normal-hearing listeners and CI users employ different perceptual strategies to recognize vocal emotions, and, if so, how these differ. Voice actors were recorded pronouncing a nonce word in four different emotions: anger, sadness, joy, and relief. These recordings’ pitch cues were phonetically analyzed. The recordings were used to test 20 normal-hearing listeners’ and 20 CI users’ emotion recognition. In congruence with previous studies, high-arousal emotions had a higher mean pitch, wider pitch range, and more dominant pitches than low-arousal emotions. Regarding pitch, speakers did not differentiate emotions based on valence but on arousal. Normal-hearing listeners outperformed CI users in emotion recognition, even when presented with CI simulated stimuli. However, only normal-hearing listeners recognized one particular actor’s emotions worse than the other actors’. The groups behaved differently when presented with similar input, showing that they had to employ differing strategies. Considering the respective speaker’s deviating pronunciation, it appears that for normal-hearing listeners, mean pitch is a more salient cue than pitch range, whereas CI users are biased toward pitch range cues. PMID:27648210

Sensorineural hearing loss degrades behavioral and physiological measures of human spatial selective auditory attention

PubMed Central

Dai, Lengshi; Best, Virginia; Shinn-Cunningham, Barbara G.

2018-01-01

Listeners with sensorineural hearing loss often have trouble understanding speech amid other voices. While poor spatial hearing is often implicated, direct evidence is weak; moreover, studies suggest that reduced audibility and degraded spectrotemporal coding may explain such problems. We hypothesized that poor spatial acuity leads to difficulty deploying selective attention, which normally filters out distracting sounds. In listeners with normal hearing, selective attention causes changes in the neural responses evoked by competing sounds, which can be used to quantify the effectiveness of attentional control. Here, we used behavior and electroencephalography to explore whether control of selective auditory attention is degraded in hearing-impaired (HI) listeners. Normal-hearing (NH) and HI listeners identified a simple melody presented simultaneously with two competing melodies, each simulated from different lateral angles. We quantified performance and attentional modulation of cortical responses evoked by these competing streams. Compared with NH listeners, HI listeners had poorer sensitivity to spatial cues, performed more poorly on the selective attention task, and showed less robust attentional modulation of cortical responses. Moreover, across NH and HI individuals, these measures were correlated. While both groups showed cortical suppression of distracting streams, this modulation was weaker in HI listeners, especially when attending to a target at midline, surrounded by competing streams. These findings suggest that hearing loss interferes with the ability to filter out sound sources based on location, contributing to communication difficulties in social situations. These findings also have implications for technologies aiming to use neural signals to guide hearing aid processing. PMID:29555752

Assessment of a directional microphone array for hearing-impaired listeners.

PubMed

Soede, W; Bilsen, F A; Berkhout, A J

1993-08-01

Hearing-impaired listeners often have great difficulty understanding speech in surroundings with background noise or reverberation. Based on array techniques, two microphone prototypes (broadside and endfire) have been developed with strongly directional characteristics [Soede et al., "Development of a new directional hearing instrument based on array technology," J. Acoust. Soc. Am. 94, 785-798 (1993)]. Physical measurements show that the arrays attenuate reverberant sound by 6 dB (free-field) and can improve the signal-to-noise ratio by 7 dB in a diffuse noise field (measured with a KEMAR manikin). For the clinical assessment of these microphones an experimental setup was made in a sound-insulated listening room with one loudspeaker in front of the listener simulating the partner in a discussion and eight loudspeakers placed on the edges of a cube producing a diffuse background noise. The hearing-impaired subject wearing his own (familiar) hearing aid is placed in the center of the cube. The speech-reception threshold in noise for simple Dutch sentences was determined with a normal single omnidirectional microphone and with one of the microphone arrays. The results of monaural listening tests with hearing impaired subjects show that in comparison with an omnidirectional hearing-aid microphone the broadside and endfire microphone array gives a mean improvement of the speech reception threshold in noise of 7.0 dB (26 subjects) and 6.8 dB (27 subjects), respectively. Binaural listening with two endfire microphone arrays gives a binaural improvement which is comparable to the binaural improvement obtained by listening with two normal ears or two conventional hearing aids.

Effects of Hearing Loss on Dual-Task Performance in an Audiovisual Virtual Reality Simulation of Listening While Walking.

PubMed

Lau, Sin Tung; Pichora-Fuller, M Kathleen; Li, Karen Z H; Singh, Gurjit; Campos, Jennifer L

2016-07-01

Most activities of daily living require the dynamic integration of sights, sounds, and movements as people navigate complex environments. Nevertheless, little is known about the effects of hearing loss (HL) or hearing aid (HA) use on listening during multitasking challenges. The objective of the current study was to investigate the effect of age-related hearing loss (ARHL) on word recognition accuracy in a dual-task experiment. Virtual reality (VR) technologies in a specialized laboratory (Challenging Environment Assessment Laboratory) were used to produce a controlled and safe simulated environment for listening while walking. In a simulation of a downtown street intersection, participants completed two single-task conditions, listening-only (standing stationary) and walking-only (walking on a treadmill to cross the simulated intersection with no speech presented), and a dual-task condition (listening while walking). For the listening task, they were required to recognize words spoken by a target talker when there was a competing talker. For some blocks of trials, the target talker was always located at 0° azimuth (100% probability condition); for other blocks, the target talker was more likely (60% of trials) to be located at the center (0° azimuth) and less likely (40% of trials) to be located at the left (270° azimuth). The participants were eight older adults with bilateral HL (mean age = 73.3 yr, standard deviation [SD] = 8.4; three males) who wore their own HAs during testing and eight controls with normal hearing (NH) thresholds (mean age = 69.9 yr, SD = 5.4; two males). No participant had clinically significant visual, cognitive, or mobility impairments. Word recognition accuracy and kinematic parameters (head and trunk angles, step width and length, stride time, cadence) were analyzed using mixed factorial analysis of variances with group as a between-subjects factor. Task condition (single versus dual) and probability (100% versus 60%) were within-subject factors. In analyses of the 60% listening condition, spatial expectation (likely versus unlikely) was a within-subject factor. Differences between groups in age and baseline measures of hearing, mobility, and cognition were tested using t tests. The NH group had significantly better word recognition accuracy than the HL group. Both groups performed better when the probability was higher and the target location more likely. For word recognition, dual-task costs for the HL group did not depend on condition, whereas the NH group demonstrated a surprising dual-task benefit in conditions with lower probability or spatial expectation. For the kinematic parameters, both groups demonstrated a more upright and less variable head position and more variable trunk position during dual-task conditions compared to the walking-only condition, suggesting that safe walking was prioritized. The HL group demonstrated more overall stride time variability than the NH group. This study provides new knowledge about the effects of ARHL, HA use, and aging on word recognition when individuals also perform a mobility-related task that is typically experienced in everyday life. This research may help inform the development of more effective function-based approaches to assessment and intervention for people who are hard-of-hearing. American Academy of Audiology.

Basic guidelines to introduce electric circuit simulation software in a general physics course

NASA Astrophysics Data System (ADS)

Moya, A. A.

2018-05-01

The introduction of electric circuit simulation software for undergraduate students in a general physics course is proposed in order to contribute to the constructive learning of electric circuit theory. This work focuses on the lab exercises based on dc, transient and ac analysis in electric circuits found in introductory physics courses, and shows how students can use the simulation software to do simple activities associated with a lab exercise itself and with related topics. By introducing electric circuit simulation programs in a general physics course as a brief activitiy complementing lab exercise, students develop basic skills in using simulation software, improve their knowledge on the topology of electric circuits and perceive that the technology contributes to their learning, all without reducing the time spent on the actual content of the course.

Electrical Engineering and Nontechnical Design Variables of Multiple Inductive Loop Systems for Auditoriums

ERIC Educational Resources Information Center

Alterovitz, Gil

2004-01-01

This research analyzed both engineering and nontechnical issues involved in the use of Induction Loop Amplification (ILA) devices in auditoriums or large gathering places for hard-of-hearing individuals. A variety of parameters need to be taken into account to determine an optimal shape/configuration for the ILA device. In many cases, an optimal…

From Archi Torture to Architecture: Undergraduate Students Design and Implement Computers Using the Multimedia Logic Emulator

ERIC Educational Resources Information Center

Stanley, Timothy D.; Wong, Lap Kei; Prigmore, Daniel; Benson, Justin; Fishler, Nathan; Fife, Leslie; Colton, Don

2007-01-01

Students learn better when they both hear and do. In computer architecture courses "doing" can be difficult in small schools without hardware laboratories hosted by computer engineering, electrical engineering, or similar departments. Software solutions exist. Our success with George Mills' Multimedia Logic (MML) is the focus of this paper. MML…

Brian hears: online auditory processing using vectorization over channels.

PubMed

Fontaine, Bertrand; Goodman, Dan F M; Benichoux, Victor; Brette, Romain

2011-01-01

The human cochlea includes about 3000 inner hair cells which filter sounds at frequencies between 20 Hz and 20 kHz. This massively parallel frequency analysis is reflected in models of auditory processing, which are often based on banks of filters. However, existing implementations do not exploit this parallelism. Here we propose algorithms to simulate these models by vectorizing computation over frequency channels, which are implemented in "Brian Hears," a library for the spiking neural network simulator package "Brian." This approach allows us to use high-level programming languages such as Python, because with vectorized operations, the computational cost of interpretation represents a small fraction of the total cost. This makes it possible to define and simulate complex models in a simple way, while all previous implementations were model-specific. In addition, we show that these algorithms can be naturally parallelized using graphics processing units, yielding substantial speed improvements. We demonstrate these algorithms with several state-of-the-art cochlear models, and show that they compare favorably with existing, less flexible, implementations.

Music preferences with hearing aids: effects of signal properties, compression settings, and listener characteristics.

PubMed

Croghan, Naomi B H; Arehart, Kathryn H; Kates, James M

2014-01-01

Current knowledge of how to design and fit hearing aids to optimize music listening is limited. Many hearing-aid users listen to recorded music, which often undergoes compression limiting (CL) in the music industry. Therefore, hearing-aid users may experience twofold effects of compression when listening to recorded music: music-industry CL and hearing-aid wide dynamic-range compression (WDRC). The goal of this study was to examine the roles of input-signal properties, hearing-aid processing, and individual variability in the perception of recorded music, with a focus on the effects of dynamic-range compression. A group of 18 experienced hearing-aid users made paired-comparison preference judgments for classical and rock music samples using simulated hearing aids. Music samples were either unprocessed before hearing-aid input or had different levels of music-industry CL. Hearing-aid conditions included linear gain and individually fitted WDRC. Combinations of four WDRC parameters were included: fast release time (50 msec), slow release time (1,000 msec), three channels, and 18 channels. Listeners also completed several psychophysical tasks. Acoustic analyses showed that CL and WDRC reduced temporal envelope contrasts, changed amplitude distributions across the acoustic spectrum, and smoothed the peaks of the modulation spectrum. Listener judgments revealed that fast WDRC was least preferred for both genres of music. For classical music, linear processing and slow WDRC were equally preferred, and the main effect of number of channels was not significant. For rock music, linear processing was preferred over slow WDRC, and three channels were preferred to 18 channels. Heavy CL was least preferred for classical music, but the amount of CL did not change the patterns of WDRC preferences for either genre. Auditory filter bandwidth as estimated from psychophysical tuning curves was associated with variability in listeners' preferences for classical music. Fast, multichannel WDRC often leads to poor music quality, whereas linear processing or slow WDRC are generally preferred. Furthermore, the effect of WDRC is more important for music preferences than music-industry CL applied to signals before the hearing-aid input stage. Variability in hearing-aid users' perceptions of music quality may be partially explained by frequency resolution abilities.

Perception of Binaural Cues Develops in Children Who Are Deaf through Bilateral Cochlear Implantation

PubMed Central

Gordon, Karen A.; Deighton, Michael R.; Abbasalipour, Parvaneh; Papsin, Blake C.

2014-01-01

There are significant challenges to restoring binaural hearing to children who have been deaf from an early age. The uncoordinated and poor temporal information available from cochlear implants distorts perception of interaural timing differences normally important for sound localization and listening in noise. Moreover, binaural development can be compromised by bilateral and unilateral auditory deprivation. Here, we studied perception of both interaural level and timing differences in 79 children/adolescents using bilateral cochlear implants and 16 peers with normal hearing. They were asked on which side of their head they heard unilaterally or bilaterally presented click- or electrical pulse- trains. Interaural level cues were identified by most participants including adolescents with long periods of unilateral cochlear implant use and little bilateral implant experience. Interaural timing cues were not detected by new bilateral adolescent users, consistent with previous evidence. Evidence of binaural timing detection was, for the first time, found in children who had much longer implant experience but it was marked by poorer than normal sensitivity and abnormally strong dependence on current level differences between implants. In addition, children with prior unilateral implant use showed a higher proportion of responses to their first implanted sides than children implanted simultaneously. These data indicate that there are functional repercussions of developing binaural hearing through bilateral cochlear implants, particularly when provided sequentially; nonetheless, children have an opportunity to use these devices to hear better in noise and gain spatial hearing. PMID:25531107

Accuracy of cochlear implant recipients in speech reception in the presence of background music.

PubMed

Gfeller, Kate; Turner, Christopher; Oleson, Jacob; Kliethermes, Stephanie; Driscoll, Virginia

2012-12-01

This study examined speech recognition abilities of cochlear implant (CI) recipients in the spectrally complex listening condition of 3 contrasting types of background music, and compared performance based upon listener groups: CI recipients using conventional long-electrode devices, Hybrid CI recipients (acoustic plus electric stimulation), and normal-hearing adults. We tested 154 long-electrode CI recipients using varied devices and strategies, 21 Hybrid CI recipients, and 49 normal-hearing adults on closed-set recognition of spondees presented in 3 contrasting forms of background music (piano solo, large symphony orchestra, vocal solo with small combo accompaniment) in an adaptive test. Signal-to-noise ratio thresholds for speech in music were examined in relation to measures of speech recognition in background noise and multitalker babble, pitch perception, and music experience. The signal-to-noise ratio thresholds for speech in music varied as a function of category of background music, group membership (long-electrode, Hybrid, normal-hearing), and age. The thresholds for speech in background music were significantly correlated with measures of pitch perception and thresholds for speech in background noise; auditory status was an important predictor. Evidence suggests that speech reception thresholds in background music change as a function of listener age (with more advanced age being detrimental), structural characteristics of different types of music, and hearing status (residual hearing). These findings have implications for everyday listening conditions such as communicating in social or commercial situations in which there is background music.

A Genetic Basis for Mechanosensory Traits in Humans

PubMed Central

Frenzel, Henning; Bohlender, Jörg; Pinsker, Katrin; Wohlleben, Bärbel; Tank, Jens; Lechner, Stefan G.; Schiska, Daniela; Jaijo, Teresa; Rüschendorf, Franz; Saar, Kathrin; Jordan, Jens; Millán, José M.; Gross, Manfred; Lewin, Gary R.

2012-01-01

In all vertebrates hearing and touch represent two distinct sensory systems that both rely on the transformation of mechanical force into electrical signals. There is an extensive literature describing single gene mutations in humans that cause hearing impairment, but there are essentially none for touch. Here we first asked if touch sensitivity is a heritable trait and second whether there are common genes that influence different mechanosensory senses like hearing and touch in humans. Using a classical twin study design we demonstrate that touch sensitivity and touch acuity are highly heritable traits. Quantitative phenotypic measures of different mechanosensory systems revealed significant correlations between touch and hearing acuity in a healthy human population. Thus mutations in genes causing deafness genes could conceivably negatively influence touch sensitivity. In agreement with this hypothesis we found that a proportion of a cohort of congenitally deaf young adults display significantly impaired measures of touch sensitivity compared to controls. In contrast, blind individuals showed enhanced, not diminished touch acuity. Finally, by examining a cohort of patients with Usher syndrome, a genetically well-characterized deaf-blindness syndrome, we could show that recessive pathogenic mutations in the USH2A gene influence touch acuity. Control Usher syndrome cohorts lacking demonstrable pathogenic USH2A mutations showed no impairment in touch acuity. Our study thus provides comprehensive evidence that there are common genetic elements that contribute to touch and hearing and has identified one of these genes as USH2A. PMID:22563300

Order-restricted inference for multivariate longitudinal data with applications to the natural history of hearing loss.

PubMed

Rosen, Sophia; Davidov, Ori

2012-07-20

Multivariate outcomes are often measured longitudinally. For example, in hearing loss studies, hearing thresholds for each subject are measured repeatedly over time at several frequencies. Thus, each patient is associated with a multivariate longitudinal outcome. The multivariate mixed-effects model is a useful tool for the analysis of such data. There are situations in which the parameters of the model are subject to some restrictions or constraints. For example, it is known that hearing thresholds, at every frequency, increase with age. Moreover, this age-related threshold elevation is monotone in frequency, that is, the higher the frequency, the higher, on average, is the rate of threshold elevation. This means that there is a natural ordering among the different frequencies in the rate of hearing loss. In practice, this amounts to imposing a set of constraints on the different frequencies' regression coefficients modeling the mean effect of time and age at entry to the study on hearing thresholds. The aforementioned constraints should be accounted for in the analysis. The result is a multivariate longitudinal model with restricted parameters. We propose estimation and testing procedures for such models. We show that ignoring the constraints may lead to misleading inferences regarding the direction and the magnitude of various effects. Moreover, simulations show that incorporating the constraints substantially improves the mean squared error of the estimates and the power of the tests. We used this methodology to analyze a real hearing loss study. Copyright © 2012 John Wiley & Sons, Ltd.

Coal conversion legislation. Part I. Hearings before the Subcommittee on Energy Production and Supply of the Committee on Energy and Natural Resources, United States Senate, Ninety-Fifth Congress, First Session on S. 272, S. 273, and S. 977, March 21 and 29, 1977. [Coal utilization

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

Not Available

1977-01-01

The legislation on greater coal utilization before the committee includes S. 272 (requiring, to the extent practicable, electric power plants and major fuel-bearing installations to utilize fuels other than natural gas); S. 273 (requiring, to the extent practicable, new electric power plants and new major fuel-burning installations be constructed to utliize fuels other than natural gas or petroleum); and S. 977 (requiring, to the extent practicable, existing electric power plants and major fuel-burning installations to utilize fuels other than natural gas or petroleum). Statements were heard from seven senators and representatives from the following: American Electric Power Service Corp., Americanmore » Boiler Manufactures Association, National Electric Reliability Council, Virgina Electric and Power Co., Fossil Power Systems, Houston Lighting and Power Co., other electric utility industry representatives, and the Federal Energy Adminstration. Additional material from the Wall Street Journal and the Washington Post is included. (MCW)« less

Electric/Hybrid Vehicle Simulation

NASA Technical Reports Server (NTRS)

Slusser, R. A.; Chapman, C. P.; Brennand, J. P.

1985-01-01

ELVEC computer program provides vehicle designer with simulation tool for detailed studies of electric and hybrid vehicle performance and cost. ELVEC simulates performance of user-specified electric or hybrid vehicle under user specified driving schedule profile or operating schedule. ELVEC performs vehicle design and life cycle cost analysis.

Recruitment of the auditory cortex in congenitally deaf cats by long-term cochlear electrostimulation.

PubMed

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

1999-09-10

In congenitally deaf cats, the central auditory system is deprived of acoustic input because of degeneration of the organ of Corti before the onset of hearing. Primary auditory afferents survive and can be stimulated electrically. By means of an intracochlear implant and an accompanying sound processor, congenitally deaf kittens were exposed to sounds and conditioned to respond to tones. After months of exposure to meaningful stimuli, the cortical activity in chronically implanted cats produced field potentials of higher amplitudes, expanded in area, developed long latency responses indicative of intracortical information processing, and showed more synaptic efficacy than in naïve, unstimulated deaf cats. The activity established by auditory experience resembles activity in hearing animals.

Artificial organs: recent progress in artificial hearing and vision.

PubMed

Ifukube, Tohru

2009-01-01

Artificial sensory organs are a prosthetic means of sending visual or auditory information to the brain by electrical stimulation of the optic or auditory nerves to assist visually impaired or hearing-impaired people. However, clinical application of artificial sensory organs, except for cochlear implants, is still a trial-and-error process. This is because how and where the information transmitted to the brain is processed is still unknown, and also because changes in brain function (plasticity) remain unknown, even though brain plasticity plays an important role in meaningful interpretation of new sensory stimuli. This article discusses some basic unresolved issues and potential solutions in the development of artificial sensory organs such as cochlear implants, brainstem implants, artificial vision, and artificial retinas.

Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness

PubMed Central

Ma, Ning; Morris, Saffron; Kitterick, Pádraig Thomas

2016-01-01

Objectives: This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place. Design: Eight NH volunteers participated in the study and listened to sentences embedded in background noise via headphones. Stimuli presented to the left ear were unprocessed. Stimuli presented to the right ear (referred to as the CI-simulation ear) were processed using an eight-channel noise vocoder with one of the three processing strategies. An Ideal strategy simulated a frequency-to-place map across all channels that matched the delivery of spectral information between the ears. A Realistic strategy created a misalignment in the mapping of frequency to place in the CI-simulation ear where the size of the mismatch between the ears varied across channels. Finally, a Shifted strategy imposed a similar degree of misalignment in all channels, resulting in consistent mismatch between the ears across frequency. The ability to report key words in sentences was assessed under monaural and binaural listening conditions and at signal to noise ratios (SNRs) established by estimating speech-reception thresholds in each ear alone. The SNRs ensured that the monaural performance of the left ear never exceeded that of the CI-simulation ear. The advantages of binaural integration were calculated by comparing binaural performance with monaural performance using the CI-simulation ear alone. Thus, these advantages reflected the additional use of the experimentally constrained left ear and were not attributable to better-ear listening. Results: Binaural performance was as accurate as, or more accurate than, monaural performance with the CI-simulation ear alone. When both ears supported a similar level of monaural performance (50%), binaural integration advantages were found regardless of whether a mismatch was simulated or not. When the CI-simulation ear supported a superior level of monaural performance (71%), evidence of binaural integration was absent when a mismatch was simulated using both the Realistic and the Ideal processing strategies. This absence of integration could not be accounted for by ceiling effects or by changes in SNR. Conclusions: If generalizable to unilaterally deaf CI users, the results of the current simulation study would suggest that benefits to speech perception in noise can be obtained by integrating information from an implanted ear and an NH ear. A mismatch in the delivery of spectral information between the ears due to a misalignment in the mapping of frequency to place may disrupt binaural integration in situations where both ears cannot support a similar level of monaural speech understanding. Previous studies that have measured the speech perception of unilaterally deaf individuals after CI but with nonindividualized frequency-to-electrode allocations may therefore have underestimated the potential benefits of providing binaural hearing. However, it remains unclear whether the size and nature of the potential incremental benefits from individualized allocations are sufficient to justify the time and resources required to derive them based on cochlear imaging or pitch-matching tasks. PMID:27116049

Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness.

PubMed

Ma, Ning; Morris, Saffron; Kitterick, Pádraig Thomas

2016-01-01

This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place. Eight NH volunteers participated in the study and listened to sentences embedded in background noise via headphones. Stimuli presented to the left ear were unprocessed. Stimuli presented to the right ear (referred to as the CI-simulation ear) were processed using an eight-channel noise vocoder with one of the three processing strategies. An Ideal strategy simulated a frequency-to-place map across all channels that matched the delivery of spectral information between the ears. A Realistic strategy created a misalignment in the mapping of frequency to place in the CI-simulation ear where the size of the mismatch between the ears varied across channels. Finally, a Shifted strategy imposed a similar degree of misalignment in all channels, resulting in consistent mismatch between the ears across frequency. The ability to report key words in sentences was assessed under monaural and binaural listening conditions and at signal to noise ratios (SNRs) established by estimating speech-reception thresholds in each ear alone. The SNRs ensured that the monaural performance of the left ear never exceeded that of the CI-simulation ear. The advantages of binaural integration were calculated by comparing binaural performance with monaural performance using the CI-simulation ear alone. Thus, these advantages reflected the additional use of the experimentally constrained left ear and were not attributable to better-ear listening. Binaural performance was as accurate as, or more accurate than, monaural performance with the CI-simulation ear alone. When both ears supported a similar level of monaural performance (50%), binaural integration advantages were found regardless of whether a mismatch was simulated or not. When the CI-simulation ear supported a superior level of monaural performance (71%), evidence of binaural integration was absent when a mismatch was simulated using both the Realistic and the Ideal processing strategies. This absence of integration could not be accounted for by ceiling effects or by changes in SNR. If generalizable to unilaterally deaf CI users, the results of the current simulation study would suggest that benefits to speech perception in noise can be obtained by integrating information from an implanted ear and an NH ear. A mismatch in the delivery of spectral information between the ears due to a misalignment in the mapping of frequency to place may disrupt binaural integration in situations where both ears cannot support a similar level of monaural speech understanding. Previous studies that have measured the speech perception of unilaterally deaf individuals after CI but with nonindividualized frequency-to-electrode allocations may therefore have underestimated the potential benefits of providing binaural hearing. However, it remains unclear whether the size and nature of the potential incremental benefits from individualized allocations are sufficient to justify the time and resources required to derive them based on cochlear imaging or pitch-matching tasks.

Suppression tuning of distortion-product otoacoustic emissions: Results from cochlear mechanics simulation

PubMed Central

Liu, Yi-Wen; Neely, Stephen T.

2013-01-01

This paper presents the results of simulating the acoustic suppression of distortion-product otoacoustic emissions (DPOAEs) from a computer model of cochlear mechanics. A tone suppressor was introduced, causing the DPOAE level to decrease, and the decrement was plotted against an increasing suppressor level. Suppression threshold was estimated from the resulting suppression growth functions (SGFs), and suppression tuning curves (STCs) were obtained by plotting the suppression threshold as a function of suppressor frequency. Results show that the slope of SGFs is generally higher for low-frequency suppressors than high-frequency suppressors, resembling those obtained from normal hearing human ears. By comparing responses of normal (100%) vs reduced (50%) outer-hair-cell sensitivities, the model predicts that the tip-to-tail difference of the STCs correlates well with that of intra-cochlear iso-displacement tuning curves. The correlation is poorer, however, between the sharpness of the STCs and that of the intra-cochlear tuning curves. These results agree qualitatively with what was recently reported from normal-hearing and hearing-impaired human subjects, and examination of intra-cochlear model responses can provide the needed insight regarding the interpretation of DPOAE STCs obtained in individual ears. PMID:23363112

Auditory and behavioral responses of California sea lions (Zalophus californianus) to single underwater impulses from an arc-gap transducer.

PubMed

Finneran, James J; Dear, Randall; Carder, Donald A; Ridgway, Sam H

2003-09-01

A behavioral response paradigm was used to measure underwater hearing thresholds in two California sea lions (Zalophus californianus) before and after exposure to underwater impulses from an arc-gap transducer. Preexposure and postexposure hearing thresholds were compared to determine if the subjects experienced temporary shifts in their masked hearing thresholds (MTTS). Hearing thresholds were measured at 1 and 10 kHz. Exposures consisted of single underwater impulses produced by an arc-gap transducer referred to as a "pulsed power device" (PPD). The electrical charge of the PPD was varied from 1.32 to 2.77 kJ; the distance between the subject and the PPD was varied over the range 3.4 to 25 m. No MTTS was observed in either subject at the highest received levels: peak pressures of approximately 6.8 and 14 kPa, rms pressures of approximately 178 and 183 dB re: 1 microPa, and total energy fluxes of 161 and 163 dB re: 1 microPa2s for the two subjects. Behavioral reactions to the tests were observed in both subjects. These reactions primarily consisted of temporary avoidance of the site where exposure to the PPD impulse had previously occurred.

Direct recordings from the auditory cortex in a cochlear implant user.

PubMed

Nourski, Kirill V; Etler, Christine P; Brugge, John F; Oya, Hiroyuki; Kawasaki, Hiroto; Reale, Richard A; Abbas, Paul J; Brown, Carolyn J; Howard, Matthew A

2013-06-01

Electrical stimulation of the auditory nerve with a cochlear implant (CI) is the method of choice for treatment of severe-to-profound hearing loss. Understanding how the human auditory cortex responds to CI stimulation is important for advances in stimulation paradigms and rehabilitation strategies. In this study, auditory cortical responses to CI stimulation were recorded intracranially in a neurosurgical patient to examine directly the functional organization of the auditory cortex and compare the findings with those obtained in normal-hearing subjects. The subject was a bilateral CI user with a 20-year history of deafness and refractory epilepsy. As part of the epilepsy treatment, a subdural grid electrode was implanted over the left temporal lobe. Pure tones, click trains, sinusoidal amplitude-modulated noise, and speech were presented via the auxiliary input of the right CI speech processor. Additional experiments were conducted with bilateral CI stimulation. Auditory event-related changes in cortical activity, characterized by the averaged evoked potential and event-related band power, were localized to posterolateral superior temporal gyrus. Responses were stable across recording sessions and were abolished under general anesthesia. Response latency decreased and magnitude increased with increasing stimulus level. More apical intracochlear stimulation yielded the largest responses. Cortical evoked potentials were phase-locked to the temporal modulations of periodic stimuli and speech utterances. Bilateral electrical stimulation resulted in minimal artifact contamination. This study demonstrates the feasibility of intracranial electrophysiological recordings of responses to CI stimulation in a human subject, shows that cortical response properties may be similar to those obtained in normal-hearing individuals, and provides a basis for future comparisons with extracranial recordings.

Power capacity from earcanal dynamic motion

NASA Astrophysics Data System (ADS)

Carioli, Johan; Delnavaz, Aidin; Zednik, Ricardo J.; Voix, Jérémie

2016-12-01

In-ear devices, such as a hearing aids, electronic earplugs, and wearables, need electrical power to operate. Batteries are the current solution, but unfortunately they also create other problems. For example, several hundred million users, mostly elderly, must change their hearing aid batteries on a weekly basis, which represents not only significant financial costs but a negative environmental impact. A promising alternative involves harvesting energy by converting the dynamic jaw movements into electrical energy via the earcanal. The extent that jaw movements distort the earcanal is still unknown, making it difficult to design the appropriate energy harvesting system for the earplug. Moreover, the finite element methods are barely capable to model the behavior of the earcanal distortion because of the complexity of mechanisms that deform the earcanal. However, this paper presents an alternative method, based on analytical considerations, to understand in-ear mechanical quasi-static deformations using earcanal point clouds. This model quantifies the bending and compressive movements of the earcanal. It can therefore be used to select an appropriate deformation mode for harvesting energy from the earcanal's dynamic motion. The value of this approach was illustrated by calculating the obtainable mechanical energy from 12 human subjects. On average, the bending energy in a human earcanal was found to be three times greater than the radial compression energy. This key finding will need to be considered in the design of future in-ear energy harvesting devices. Such an energy harvesting device has the potential to revolutionize the market for in-ear wearable devices and hearing aids by complementing or replacing battery technology.

Acoustic neuroma: potential risk factors and audiometric surveillance in the aluminium industry

PubMed Central

Taiwo, Oyebode; Galusha, Deron; Tessier-Sherman, Baylah; Kirsche, Sharon; Cantley, Linda; Slade, Martin D; Cullen, Mark R; Donoghue, A Michael

2014-01-01

Objectives To look for an association between acoustic neuroma (AN) and participation in a hearing conservation programme (HCP) and also for an association between AN and possible occupational risk factors in the aluminium industry. Methods We conducted a case–control analysis of a population of US aluminium production workers in 8 smelters and 43 other plants. Using insurance claims data, 97 cases of AN were identified between 1996 and 2009. Each was matched with four controls. Covariates included participation in a HCP, working in an aluminium smelter, working in an electrical job and hearing loss. Results In the bivariate analyses, covariates associated with AN were participation in the HCP (OR=1.72; 95% CI 1.09 to 2.69) and smelter work (OR=1.88; 95% CI 1.06 to 3.36). Electrical work was not significant (OR=1.60; 95% CI 0.65 to 3.94). Owing to high participation in the HCP in smelters, multivariate subanalyses were required. In the multivariate analyses, participation in the HCP was the only statistically significant risk factor for AN. In the multivariate analysis restricted to employees not working in a smelter, the OR was 1.81 (95% CI 1.04 to 3.17). Hearing loss, an indirect measure of in-ear noise dose, was not predictive of AN. Conclusions Our results suggest the incidental detection of previously undiagnosed tumours in workers who participated in the company-sponsored HCP. The increased medical surveillance among this population of workers most likely introduced detection bias, leading to the identification of AN cases that would have otherwise remained undetected. PMID:25015928

An application of boundary element method calculations to hearing aid systems: The influence of the human head

NASA Astrophysics Data System (ADS)

Rasmussen, Karsten B.; Juhl, Peter

2004-05-01

Boundary element method (BEM) calculations are used for the purpose of predicting the acoustic influence of the human head in two cases. In the first case the sound source is the mouth and in the second case the sound is plane waves arriving from different directions in the horizontal plane. In both cases the sound field is studied in relation to two positions above the right ear being representative of hearing aid microphone positions. Both cases are relevant for hearing aid development. The calculations are based upon a direct BEM implementation in Matlab. The meshing is based on the original geometrical data files describing the B&K Head and Torso Simulator 4128 combined with a 3D scan of the pinna.

Crip for a day: The unintended negative consequences of disability simulations.

PubMed

Nario-Redmond, Michelle R; Gospodinov, Dobromir; Cobb, Angela

2017-08-01

To investigate the impact of disability simulations on mood, self-ascribed disability stereotypes, attitudes about interacting with disabled individuals, and behavioral intentions for improving campus accessibility. Experiment 1 evaluated disability-awareness simulations by randomly assigning undergraduates (N = 60) with and without disabilities to stations simulating either dyslexia, hearing or mobility impairments. Experiment 2 extended the field study into the lab where undergraduates (N = 50) with and without disabilities each completed low vision, hearing impairment, and dyslexia simulations. Both studies incorporated pretest-posttest measures of mood, self-ascribed disability stereotypes, and attitudinal measures. In both experiments, disability simulations made participants feel more confused, embarrassed, helpless, and more vulnerable to becoming disabled themselves compared to baseline. Following the simulations, empathetic concern (warmth) toward disabled people increased in both studies, but attitudes about interacting did not improve. In Experiment 1, postsimulation anxiety, embarrassment, and helplessness were highest for those who used wheelchairs or simulated dyslexia. In Experiment 2, participants judged themselves less competent, expressed more pity, expressed more interaction discomfort, and were not more willing to interview disabled students for an accessibility project following the simulations compared to baseline. In addition, Experiment 2 found frustration, guilt, anxiety, and depression were most pronounced among those who interacted with disabled people less than once per month. Simulating disabilities promotes distress and fails to improve attitudes toward disabled people, undermining efforts to improve integration even while participants report more empathetic concern and "understanding of what the disability experience is like." (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Planck Visualization Project: Seeing and Hearing the CMB

NASA Astrophysics Data System (ADS)

Van Der Veen, Jatila; Lubin, P. M.; 2; Alper, B.; 3; Smith, W.; 4; McGee, R.; 5; US Planck Collaboration

2011-01-01

The Planck Education and Public Outreach collaborators at the University of California, Santa Barbara and Purdue University have prepared a variety of materials to present the science goals of the Planck Mission to the public. Here we present our interactive simulation of the Cosmic Microwave Background, in which the user can change the ingredients of the universe and hear the different harmonics. We also present how we derive information about the early universe from the power spectrum of the CMB by using the physics of music for the public.

A framework for geometry acquisition, 3-D printing, simulation, and measurement of head-related transfer functions with a focus on hearing-assistive devices

PubMed Central

Harder, Stine; Paulsen, Rasmus R.; Larsen, Martin; Laugesen, Søren; Mihocic, Michael; Majdak, Piotr

2017-01-01

Individual head-related transfer functions (HRTFs) are essential in applications like fitting hearing-assistive devices (HADs) for providing accurate sound localization performance. Individual HRTFs are usually obtained through intricate acoustic measurements. This paper investigates the use of a three-dimensional (3D) head model for acquisition of individual HRTFs. Two aspects were investigated; whether a 3D-printed model can replace measurements on a human listener and whether numerical simulations can replace acoustic measurements. For this purpose, HRTFs were acoustically measured for four human listeners and for a 3D printed head model of one of these listeners. Further, HRTFs were simulated by applying the finite element method to the 3D head model. The monaural spectral features and spectral distortions were very similar between re-measurements and between human and printed measurements, however larger deviations were observed between measurement and simulation. The binaural cues were in agreement among all HRTFs of the same listener, indicating that the 3D model is able to provide localization cues potentially accessible to HAD users. Hence, the pipeline of geometry acquisition, printing, and acoustic measurements or simulations, seems to be a promising step forward towards in-silico design of HADs. PMID:28239188

76 FR 54261 - Carolina Power & Light; H.B. Robinson Steam Electric Plant, Unit No. 2; HBRSEP Independent Spent...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-31

... via electronic submission through the NRC E-Filing system. Requests for a hearing and petitions for... entities participating under 10 CFR 2.315(c), must be filed in accordance with the NRC E-Filing rule (72 FR 49139, August 28, 2007). The E-Filing process requires participants to submit and serve all adjudicatory...

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Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-14

... electronic submission through the NRC E-filing system. Requests for a hearing and petitions for leave to... entities participating under 10 CFR 2.315(c), must be filed in accordance with the NRC E-Filing rule (72 FR 49139, August 28, 2007). The E-Filing process requires participants to submit and serve all adjudicatory...

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Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-30

... submission through the NRC E-Filing system. Requests for a hearing and petitions for leave to intervene... participating under 10 CFR 2.315(c), must be filed in accordance with the NRC E-Filing rule (72 FR 49139, August 28, 2007). The E-Filing process requires participants to submit and serve all adjudicatory documents...

Dynamic Pressure Microphones

NASA Astrophysics Data System (ADS)

Werner, E.

In 1876, Alexander Graham Bell described his first telephone with a microphone using magnetic induction to convert the voice input into an electric output signal. The basic principle led to a variety of designs optimized for different needs, from hearing impaired users to singers or broadcast announcers. From the various sound pressure versions, only the moving coil design is still in mass production for speech and music application.

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Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-22

... to generate electric power and would capture carbon dioxide (CO 2 ) for use in enhanced oil recovery... cooperative agreement. The polygen plant would be built on a 600 acre oil field site in Ector County, Texas, north of the abandoned oil town of Penwell. Summit would design and construct the plant to capture...

Reduced electromotility of outer hair cells associated with connexin-related forms of deafness: an in silico study of a cochlear network mechanism.

PubMed

Mistrík, Pavel; Ashmore, Jonathan F

2010-12-01

Mutations in the GJB2 gene encoding for the connexin 26 (Cx26) protein are the most common source of nonsyndromic forms of deafness. Cx26 is a building block of gap junctions (GJs) which establish electrical connectivity in distinct cochlear compartments by allowing intercellular ionic (and metabolic) exchange. Animal models of the Cx26 deficiency in the organ of Corti seem to suggest that the hearing loss and the degeneration of outer hair cells (OHCs) and inner hair cells is due to failed K(+) and metabolite homeostasis. However, OHCs can develop normally in some mutants, suggesting that the hair cells death is not the universal mechanism. In search for alternatives, we have developed an in silico large scale three-dimensional model of electrical current flow in the cochlea in the small signal, linearised, regime. The effect of mutations was analysed by varying the magnitude of resistive components representing the GJ network in the organ of Corti. The simulations indeed show that reduced GJ conductivity increases the attenuation of the OHC transmembrane potential at frequencies above 5 kHz from 6.1 dB/decade in the wild-type to 14.2 dB/decade. As a consequence of increased GJ electrical filtering, the OHC transmembrane potential is reduced by up to 35 dB at frequencies >10 kHz. OHC electromotility, driven by this potential, is crucial for sound amplification, cochlear sensitivity and frequency selectivity. Therefore, we conclude that reduced OHC electromotility may represent an additional mechanism underlying deafness in the presence of Cx26 mutations and may explain lowered OHC functionality in particular reported Cx26 mutants.

Factors affecting speech understanding in gated interference: Cochlear implant users and normal-hearing listeners

NASA Astrophysics Data System (ADS)

Nelson, Peggy B.; Jin, Su-Hyun

2004-05-01

Previous work [Nelson, Jin, Carney, and Nelson (2003), J. Acoust. Soc. Am 113, 961-968] suggested that cochlear implant users do not benefit from masking release when listening in modulated noise. The previous findings indicated that implant users experience little to no release from masking when identifying sentences in speech-shaped noise, regardless of the modulation frequency applied to the noise. The lack of masking release occurred for all implant subjects who were using three different devices and speech processing strategies. In the present study, possible causes of this reduced masking release in implant listeners were investigated. Normal-hearing listeners, implant users, and normal-hearing listeners presented with a four-band simulation of a cochlear implant were tested for their understanding of sentences in gated noise (1-32 Hz gate frequencies) when the duty cycle of the noise was varied from 25% to 75%. No systematic effect of noise duty cycle on implant and simulation listeners' performance was noted, indicating that the masking caused by gated noise is not only energetic masking. Masking release significantly increased when the number of spectral channels was increased from 4 to 12 for simulation listeners, suggesting that spectral resolution is important for masking release. Listeners were also tested for their understanding of gated sentences (sentences in quiet interrupted by periods of silence ranging from 1 to 32 Hz as a measure of auditory fusion, or the ability to integrate speech across temporal gaps. Implant and simulation listeners had significant difficulty understanding gated sentences at every gate frequency. When the number of spectral channels was increased for simulation listeners, their ability to understand gated sentences improved significantly. Findings suggest that implant listeners' difficulty understanding speech in modulated conditions is related to at least two (possibly related) factors: degraded spectral information and limitations in auditory fusion across temporal gaps.

Kirchhoff and Ohm in action: solving electric currents in continuous extended media

NASA Astrophysics Data System (ADS)

Dolinko, A. E.

2018-03-01

In this paper we show a simple and versatile computational simulation method for determining electric currents and electric potential in 2D and 3D media with arbitrary distribution of resistivity. One of the highlights of the proposed method is that the simulation space containing the distribution of resistivity and the points of external applied voltage are introduced by means of digital images or bitmaps, which easily allows simulating any phenomena involving distributions of resistivity. The simulation is based on the Kirchhoff’s laws of electric currents and it is solved by means of an iterative procedure. The method is also generalised to account for media with distributions of reactive impedance. At the end of this work, we show an example of application of the simulation, consisting in reproducing the response obtained with the geophysical method of electric resistivity tomography in presence of soil cracks. This paper is aimed at undergraduate or graduated students interested in computational physics and electricity and also researchers involved in the area of continuous electric media, which could find a simple and powerful tool for investigation.

Camera traps can be heard and seen by animals.

PubMed

Meek, Paul D; Ballard, Guy-Anthony; Fleming, Peter J S; Schaefer, Michael; Williams, Warwick; Falzon, Greg

2014-01-01

Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5) and infrared illumination outputs (n = 7) of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21) and assessed the vision ranges (n = 3) of mammals species (where data existed) to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals' hearing and produce illumination that can be seen by many species.

Aging of the ear, exposed and not exposed to noise

NASA Astrophysics Data System (ADS)

Fleischer, Gerald; Müller, Reinhard; Heppelmann, Guido; Bache, Thomas; Gao, Xia; Wang, Feng; Huang, Weiguo

2002-05-01

Hearing in two special groups was compared, using pure-tone audiometry up to 16 kHz. One group consisted of commercial airline pilots in Germany, the other of people living in remote parts of the People's Republic of China, without electricity, cars or, other technical equipment. The age of the 502 pilots (99% male) ranged from 22 to 65 years, while that of the 644 Chinese (61% male) ranged from 6 to 82 years. In both groups participants with diseases of the ear and with acute acoustic trauma were excluded. Analysis showed that the threshold of hearing in young adults is identical in Germany and in China. It is evident that the effect of aging is reduced in pilots, as compared to people living without technical or industrial noise. Older pilots clearly hear better than people not subjected to technical noise, most prominently at higher frequencies. Together with other observations, it can be concluded that continuous wideband noise reduces the aging of the ear. Long-term exposure to such noise-within limits-appears to be good for the ear.

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

Cochlear Implants Special Issue Article: Vocal Emotion Recognition by Normal-Hearing Listeners and Cochlear Implant Users

PubMed Central

Luo, Xin; Fu, Qian-Jie; Galvin, John J.

2007-01-01

The present study investigated the ability of normal-hearing listeners and cochlear implant users to recognize vocal emotions. Sentences were produced by 1 male and 1 female talker according to 5 target emotions: angry, anxious, happy, sad, and neutral. Overall amplitude differences between the stimuli were either preserved or normalized. In experiment 1, vocal emotion recognition was measured in normal-hearing and cochlear implant listeners; cochlear implant subjects were tested using their clinically assigned processors. When overall amplitude cues were preserved, normal-hearing listeners achieved near-perfect performance, whereas listeners with cochlear implant recognized less than half of the target emotions. Removing the overall amplitude cues significantly worsened mean normal-hearing and cochlear implant performance. In experiment 2, vocal emotion recognition was measured in listeners with cochlear implant as a function of the number of channels (from 1 to 8) and envelope filter cutoff frequency (50 vs 400 Hz) in experimental speech processors. In experiment 3, vocal emotion recognition was measured in normal-hearing listeners as a function of the number of channels (from 1 to 16) and envelope filter cutoff frequency (50 vs 500 Hz) in acoustic cochlear implant simulations. Results from experiments 2 and 3 showed that both cochlear implant and normal-hearing performance significantly improved as the number of channels or the envelope filter cutoff frequency was increased. The results suggest that spectral, temporal, and overall amplitude cues each contribute to vocal emotion recognition. The poorer cochlear implant performance is most likely attributable to the lack of salient pitch cues and the limited functional spectral resolution. PMID:18003871

The influence of audibility on speech recognition with nonlinear frequency compression for children and adults with hearing loss

PubMed Central

McCreery, Ryan W.; Alexander, Joshua; Brennan, Marc A.; Hoover, Brenda; Kopun, Judy; Stelmachowicz, Patricia G.

2014-01-01

Objective The primary goal of nonlinear frequency compression (NFC) and other frequency lowering strategies is to increase the audibility of high-frequency sounds that are not otherwise audible with conventional hearing-aid processing due to the degree of hearing loss, limited hearing aid bandwidth or a combination of both factors. The aim of the current study was to compare estimates of speech audibility processed by NFC to improvements in speech recognition for a group of children and adults with high-frequency hearing loss. Design Monosyllabic word recognition was measured in noise for twenty-four adults and twelve children with mild to severe sensorineural hearing loss. Stimuli were amplified based on each listener’s audiogram with conventional processing (CP) with amplitude compression or with NFC and presented under headphones using a software-based hearing aid simulator. A modification of the speech intelligibility index (SII) was used to estimate audibility of information in frequency-lowered bands. The mean improvement in SII was compared to the mean improvement in speech recognition. Results All but two listeners experienced improvements in speech recognition with NFC compared to CP, consistent with the small increase in audibility that was estimated using the modification of the SII. Children and adults had similar improvements in speech recognition with NFC. Conclusion Word recognition with NFC was higher than CP for children and adults with mild to severe hearing loss. The average improvement in speech recognition with NFC (7%) was consistent with the modified SII, which indicated that listeners experienced an increase in audibility with NFC compared to CP. Further studies are necessary to determine if changes in audibility with NFC are related to speech recognition with NFC for listeners with greater degrees of hearing loss, with a greater variety of compression settings, and using auditory training. PMID:24535558

Post-processing of auditory steady-state responses to correct spectral leakage.

PubMed

Felix, Leonardo Bonato; de Sá, Antonio Mauricio Ferreira Leite Miranda; Mendes, Eduardo Mazoni Andrade Marçal; Moraes, Márcio Flávio Dutra

2009-06-30

Auditory steady-state responses (ASSRs) are electrical manifestations of brain due to high rate sound stimulation. These evoked responses can be used to assess the hearing capabilities of a subject in an objective, automatic fashion. Usually, the detection protocol is accomplished by frequency-domain techniques, such as magnitude-squared coherence, whose estimation is based on the fast Fourier transform (FFT) of several data segments. In practice, the FFT-based spectrum may spread out the energy of a given frequency to its side bins and this escape of energy in the spectrum is called spectral leakage. The distortion of the spectrum due to leakage may severely compromise statistical significance of objective detection. This work presents an offline, a posteriori method for spectral leakage minimization in the frequency-domain analysis of ASSRs using coherent sampling criterion and interpolation in time. The technique was applied to the local field potentials of 10 Wistar rats and the results, together with those from simulated data, indicate that a leakage-free analysis of ASSRs is possible for any dataset if the methods showed in this paper were followed.

A Preliminary Investigation of the Air-Bone Gap: Changes in Intracochlear Sound Pressure With Air- and Bone-conducted Stimuli After Cochlear Implantation.

PubMed

Banakis Hartl, Renee M; Mattingly, Jameson K; Greene, Nathaniel T; Jenkins, Herman A; Cass, Stephen P; Tollin, Daniel J

2016-10-01

A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion. Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative ABG remains unexplained and could result in part from altered cochlear mechanics. Here, we sought to investigate changes to these mechanics via intracochlear pressure measurements before and after electrode implantation to quantify the contribution to postoperative ABG. Human cadaveric heads were implanted with titanium fixtures for bone conduction transducers. Velocities of stapes capitulum and cochlear promontory between the two windows were measured using single-axis laser Doppler vibrometry and fiber-optic sensors measured intracochlear pressures in scala vestibuli and tympani for air- and bone-conducted stimuli before and after cochlear implant electrode insertion through the round window. Intracochlear pressures revealed only slightly reduced responses to air-conducted stimuli consistent with previous literature. No significant changes were noted to bone-conducted stimuli after implantation. Velocities of the stapes capitulum and the cochlear promontory to both stimuli were stable after electrode placement. Presence of a cochlear implant electrode causes alterations in intracochlear sound pressure levels to air, but not bone, conducted stimuli and helps to explain changes in residual hearing noted clinically. These results suggest the possibility of a cochlear conductive component to postoperative changes in hearing sensitivity.

Accessibility assessment of assistive technology for the hearing impaired.

PubMed

Áfio, Aline Cruz Esmeraldo; Carvalho, Aline Tomaz de; Caravalho, Luciana Vieira de; Silva, Andréa Soares Rocha da; Pagliuca, Lorita Marlena Freitag

2016-01-01

to assess the automatic accessibility of assistive technology in online courses for the hearing impaired. evaluation study guided by the Assessment and Maintenance step proposed in the Model of Development of Digital Educational Material. The software Assessor and Simulator for the Accessibility of Sites (ASES) was used to analyze the online course "Education on Sexual and Reproductive Health: the use of condoms" according to the accessibility standards of national and international websites. an error report generated by the program identified, in each didactic module, one error and two warnings related to two international principles and six warnings involved with six national recommendations. The warnings relevant to hearing-impaired people were corrected, and the course was considered accessible by automatic assessment. we concluded that the pages of the course were considered, by the software used, appropriate to the standards of web accessibility.

Passive flow heat exchanger simulation for power generation from solar pond using thermoelectric generators

NASA Astrophysics Data System (ADS)

Baharin, Nuraida'Aadilia; Arzami, Amir Afiq; Singh, Baljit; Remeli, Muhammad Fairuz; Tan, Lippong; Oberoi, Amandeep

2017-04-01

In this study, a thermoelectric generator heat exchanger system was designed and simulated for electricity generation from solar pond. A thermoelectric generator heat exchanger was studied by using Computational Fluid Dynamics to simulate flow and heat transfer. A thermoelectric generator heat exchanger designed for passive in-pond flow used in solar pond for electrical power generation. A simple analysis simulation was developed to obtain the amount of electricity generated at different conditions for hot temperatures of a solar pond at different flow rates. Results indicated that the system is capable of producing electricity. This study and design provides an alternative way to generate electricity from solar pond in tropical countries like Malaysia for possible renewable energy applications.

Assessment of Capabilities for First-Principles Simulation of Spacecraft Electric Propulsion Systems and Plasma Spacecraft Environment

DTIC Science & Technology

2016-04-29

Simulation of Spacecraft Electric Propulsion Systems and Plasma Spacecraft Environment 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...Assessment of Capabilities for First‐ Principles Simulation of Spacecraft Electric  Propulsion   Systems and Plasma Spacecraft Environment” Team leader(s

Infrared neural stimulation (INS) inhibits electrically evoked neural responses in the deaf white cat

NASA Astrophysics Data System (ADS)

Richter, Claus-Peter; Rajguru, Suhrud M.; Robinson, Alan; Young, Hunter K.

2014-03-01

Infrared neural stimulation (INS) has been used in the past to evoke neural activity from hearing and partially deaf animals. All the responses were excitatory. In Aplysia californica, Duke and coworkers demonstrated that INS also inhibits neural responses [1], which similar observations were made in the vestibular system [2, 3]. In deaf white cats that have cochleae with largely reduced spiral ganglion neuron counts and a significant degeneration of the organ of Corti, no cochlear compound action potentials could be observed during INS alone. However, the combined electrical and optical stimulation demonstrated inhibitory responses during irradiation with infrared light.

Simulations of Interdigitated Electrode Interactions with Gold Nanoparticles for Impedance-Based Biosensing Applications

PubMed Central

MacKay, Scott; Hermansen, Peter; Wishart, David; Chen, Jie

2015-01-01

In this paper, we describe a point-of-care biosensor design. The uniqueness of our design is in its capability for detecting a wide variety of target biomolecules and the simplicity of nanoparticle enhanced electrical detection. The electrical properties of interdigitated electrodes (IDEs) and the mechanism for gold nanoparticle-enhanced impedance-based biosensor systems based on these electrodes are simulated using COMSOL Multiphysics software. Understanding these properties and how they can be affected is vital in designing effective biosensor devices. Simulations were used to show electrical screening develop over time for IDEs in a salt solution, as well as the electric field between individual digits of electrodes. Using these simulations, it was observed that gold nanoparticles bound closely to IDEs can lower the electric field magnitude between the digits of the electrode. The simulations are also shown to be a useful design tool in optimizing sensor function. Various different conditions, such as electrode dimensions and background ion concentrations, are shown to have a significant impact on the simulations. PMID:26364638

Structure of a force-conveying cadherin bond essential for inner-ear mechanotransduction.

PubMed

Sotomayor, Marcos; Weihofen, Wilhelm A; Gaudet, Rachelle; Corey, David P

2012-12-06

Hearing and balance use hair cells in the inner ear to transform mechanical stimuli into electrical signals. Mechanical force from sound waves or head movements is conveyed to hair-cell transduction channels by tip links, fine filaments formed by two atypical cadherins known as protocadherin 15 and cadherin 23 (refs 4, 5). These two proteins are involved in inherited deafness and feature long extracellular domains that interact tip-to-tip in a Ca(2+)-dependent manner. However, the molecular architecture of this complex is unknown. Here we combine crystallography, molecular dynamics simulations and binding experiments to characterize the protocadherin 15-cadherin 23 bond. We find a unique cadherin interaction mechanism, in which the two most amino-terminal cadherin repeats (extracellular cadherin repeats 1 and 2) of each protein interact to form an overlapped, antiparallel heterodimer. Simulations predict that this tip-link bond is mechanically strong enough to resist forces in hair cells. In addition, the complex is shown to become unstable in response to Ca(2+) removal owing to increased flexure of Ca(2+)-free cadherin repeats. Finally, we use structures and biochemical measurements to study the molecular mechanisms by which deafness mutations disrupt tip-link function. Overall, our results shed light on the molecular mechanics of hair-cell sensory transduction and on new interaction mechanisms for cadherins, a large protein family implicated in tissue and organ morphogenesis, neural connectivity and cancer.

Brian Hears: Online Auditory Processing Using Vectorization Over Channels

PubMed Central

Fontaine, Bertrand; Goodman, Dan F. M.; Benichoux, Victor; Brette, Romain

2011-01-01

The human cochlea includes about 3000 inner hair cells which filter sounds at frequencies between 20 Hz and 20 kHz. This massively parallel frequency analysis is reflected in models of auditory processing, which are often based on banks of filters. However, existing implementations do not exploit this parallelism. Here we propose algorithms to simulate these models by vectorizing computation over frequency channels, which are implemented in “Brian Hears,” a library for the spiking neural network simulator package “Brian.” This approach allows us to use high-level programming languages such as Python, because with vectorized operations, the computational cost of interpretation represents a small fraction of the total cost. This makes it possible to define and simulate complex models in a simple way, while all previous implementations were model-specific. In addition, we show that these algorithms can be naturally parallelized using graphics processing units, yielding substantial speed improvements. We demonstrate these algorithms with several state-of-the-art cochlear models, and show that they compare favorably with existing, less flexible, implementations. PMID:21811453

Hearing thresholds of a harbor porpoise (Phocoena phocoena) for helicopter dipping sonar signals (1.43-1.33 kHz) (L).

PubMed

Kastelein, Ronald A; Hoek, Lean; de Jong, Christ A F

2011-08-01

Helicopter long range active sonar (HELRAS), a "dipping" sonar system used by lowering transducer and receiver arrays into water from helicopters, produces signals within the functional hearing range of many marine animals, including the harbor porpoise. The distance at which the signals can be heard is unknown, and depends, among other factors, on the hearing sensitivity of the species to these particular signals. Therefore, the hearing thresholds of a harbor porpoise for HELRAS signals were quantified by means of a psychophysical technique. Detection thresholds were obtained for five 1.25 s simulated HELRAS signals, varying in their harmonic content and amplitude envelopes. The 50% hearing thresholds for the different signals were similar: 76 dB re 1 μPa (broadband sound pressure level, averaged over the signal duration). The detection thresholds were similar to those found in the same porpoise for tonal signals in the 1-2 kHz range measured in a previous study. Harmonic distortion, which occurred in three of the five signals, had little influence on their audibility. The results of this study, combined with information on the source level of the signal, the propagation conditions and ambient noise levels, allow the calculation of accurate estimates of the distances at which porpoises can detect HELRAS signals.

Impact of Age and Hearing Impairment on Work Performance during Long Working Hours

PubMed Central

Grossi, Nina R.; Kallus, K. Wolfgang

2018-01-01

Based on demographic prognoses, it must be assumed that a greater number of older workers will be found in the future labor market. How to deal with their possible age-related impairments of sensory functions, like hearing impairment and work performance during extended working time, has not been addressed explicitly until now. The study addresses this interplay. The study was performed on two consecutive days after normal working hours. The 55 participants had to “work” in the study at least three additional hours to simulate a situation of long working hours. The tested measures for (job) performance were: general attention, long-term selective attention, concentration, and reaction time. All of the investigated variables were taken at both days of the study (2 × 2 × 2 repeated measurement design). The results show effects for age, the interaction of hearing impairment and time of measurement, and effects of the measurement time. Older participants reacted slower than younger participants did. Furthermore, younger participants reacted more frequently in a correct way. Hearing impairment seems to have a negative impact especially on measures of false reactions, and therefore especially on measurement time 1. The results can be interpreted in a way that hearing-impaired participants are able to compensate their deficits over time. PMID:29315260

Impact of Age and Hearing Impairment on Work Performance during Long Working Hours.

PubMed

Wagner-Hartl, Verena; Grossi, Nina R; Kallus, K Wolfgang

2018-01-09

Based on demographic prognoses, it must be assumed that a greater number of older workers will be found in the future labor market. How to deal with their possible age-related impairments of sensory functions, like hearing impairment and work performance during extended working time, has not been addressed explicitly until now. The study addresses this interplay. The study was performed on two consecutive days after normal working hours. The 55 participants had to "work" in the study at least three additional hours to simulate a situation of long working hours. The tested measures for (job) performance were: general attention, long-term selective attention, concentration, and reaction time. All of the investigated variables were taken at both days of the study (2 × 2 × 2 repeated measurement design). The results show effects for age, the interaction of hearing impairment and time of measurement, and effects of the measurement time. Older participants reacted slower than younger participants did. Furthermore, younger participants reacted more frequently in a correct way. Hearing impairment seems to have a negative impact especially on measures of false reactions, and therefore especially on measurement time 1. The results can be interpreted in a way that hearing-impaired participants are able to compensate their deficits over time.

The effect of round window reinforcement on human hearing

NASA Astrophysics Data System (ADS)

Guan, Xiying; Cheng, Y. Song; Galaiya, Deepa; Nakajima, Hideko H.

2018-05-01

The compliant round window (RW) allows volume velocity to flow within the incompressible fluid of the cochlea as the oval window vibrates during sound stimulation. Recently, surgically stiffened RW is emerging as a treatment for various conditions such as superior canal dehiscence and hyperacusis. However, we lack the basic understanding of how reinforcing the RW affects sound transmission in the ear. The aim of this study is to clarify the effect of RW reinforcement on hearing. To study the effect of RW reinforcement with tissue and adhesive, we measured intracochlear pressures in scala vestibuli (Psv) and scala tympani (Pst) at the cochlear base together with stapes velocity in response to sound at the ear canal. The cochlear input drive (Pdiff = Psv - Pst, an estimate of hearing) was determined before and after RW reinforcement in a fresh human cadaveric ear. Results show that increasing the RW stiffness by reinforcement can affect the cochlear input drive in unexpected ways. Below 200 Hz, RW reinforcement resulted in reduced stapes motion, however an increase in cochlear drive, consistent with increase in hearing. At 200-1000 Hz, the hearing and stapes motion both were slightly decreased. Reinforcing the RW had no effect above 1 kHz. To understand the cochlear mechanical effects of RW reinforcement, we used a lumped-element model that simulated our findings.

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

PubMed

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

2015-10-01

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

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

PubMed Central

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

2015-01-01

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

Acoustic neuroma: potential risk factors and audiometric surveillance in the aluminium industry.

PubMed

Taiwo, Oyebode; Galusha, Deron; Tessier-Sherman, Baylah; Kirsche, Sharon; Cantley, Linda; Slade, Martin D; Cullen, Mark R; Donoghue, A Michael

2014-09-01

To look for an association between acoustic neuroma (AN) and participation in a hearing conservation programme (HCP) and also for an association between AN and possible occupational risk factors in the aluminium industry. We conducted a case-control analysis of a population of US aluminium production workers in 8 smelters and 43 other plants. Using insurance claims data, 97 cases of AN were identified between 1996 and 2009. Each was matched with four controls. Covariates included participation in a HCP, working in an aluminium smelter, working in an electrical job and hearing loss. In the bivariate analyses, covariates associated with AN were participation in the HCP (OR=1.72; 95% CI 1.09 to 2.69) and smelter work (OR=1.88; 95% CI 1.06 to 3.36). Electrical work was not significant (OR=1.60; 95% CI 0.65 to 3.94). Owing to high participation in the HCP in smelters, multivariate subanalyses were required. In the multivariate analyses, participation in the HCP was the only statistically significant risk factor for AN. In the multivariate analysis restricted to employees not working in a smelter, the OR was 1.81 (95% CI 1.04 to 3.17). Hearing loss, an indirect measure of in-ear noise dose, was not predictive of AN. Our results suggest the incidental detection of previously undiagnosed tumours in workers who participated in the company-sponsored HCP. The increased medical surveillance among this population of workers most likely introduced detection bias, leading to the identification of AN cases that would have otherwise remained undetected. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

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

PubMed

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

2016-12-01

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

EERE's State & Local Energy Data Tool

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

Shambarger, Erick; DeCesaro, Jennifer

2014-06-23

EERE's State and Local Energy Data (SLED) Tool provides basic energy market information that can help state and local governments plan and implement clean energy projects, including electricity generation; fuel sources and costs; applicable policies, regulations, and financial incentives; and renewable energy resource potential. Watch this video to learn more about the tool and hear testimonials from real users about the benefits of using this tool.

EERE's State & Local Energy Data Tool

ScienceCinema

Shambarger, Erick; DeCesaro, Jennifer

2018-05-30

EERE's State and Local Energy Data (SLED) Tool provides basic energy market information that can help state and local governments plan and implement clean energy projects, including electricity generation; fuel sources and costs; applicable policies, regulations, and financial incentives; and renewable energy resource potential. Watch this video to learn more about the tool and hear testimonials from real users about the benefits of using this tool.

Nerve Regeneration in the Peripheral Nervous System versus the Central Nervous System and the Relevance to Speech and Hearing after Nerve Injuries

ERIC Educational Resources Information Center

Gordon, Tessa; Gordon, Karen

2010-01-01

Schwann cells normally form myelin sheaths around axons in the peripheral nervous system (PNS) and support nerve regeneration after nerve injury. In contrast, nerve regeneration in the central nervous system (CNS) is not supported by the myelinating cells known as oligodendrocytes. We have found that: 1) low frequency electrical stimulation can be…

Empowering Students to Investigate Their Energy Consumption with a Safe, Easy-to-Use, Low-Cost Electrical Energy Meter

ERIC Educational Resources Information Center

Darling, Gerald

2012-01-01

Middle school students hear about energy continuously: in the news, in many of their classes, and at home. Most students realize that recent wars have been fought over energy resources, and many will accept that overreliance on fossil fuels is changing the global climate. Students understand that as the world population surges past seven billion,…

The sensitivity of hearing-impaired adults to acoustic attributes in simulated rooms

PubMed Central

Whitmer, William M.; McShefferty, David; Akeroyd, Michael A.

2016-01-01

In previous studies we have shown that older hearing-impaired individuals are relatively insensitive to changes in the apparent width of broadband noises when those width changes were based on differences in interaural coherence [W. Whitmer, B. Seeber and M. Akeroyd, J. Acoust. Soc. Am. 132, 369-379 (2012)]. This insensitivity has been linked to senescent difficulties in resolving binaural fine-structure differences. It is therefore possible that interaural coherence, despite its widespread use, may not be the best acoustic surrogate of spatial perception for the aged and impaired. To test this, we simulated the room impulse responses for various acoustic scenarios with differing coherence and lateral (energy) fraction attributes using room modelling software (ODEON). Bilaterally impaired adult participants were asked to sketch the perceived size of speech tokens and musical excerpts that were convolved with these impulse responses and presented to them in a sound-dampened enclosure through a 24-loudspeaker array. Participants’ binaural acuity was also measured using an interaural phase discrimination task. Corroborating our previous findings, the results showed less sensitivity to interaural coherence in the auditory source width judgments of older hearing-impaired individuals, indicating that alternate acoustic measurements in the design of spaces for the elderly may be necessary. PMID:27213028

Microscopic prediction of speech intelligibility in spatially distributed speech-shaped noise for normal-hearing listeners.

PubMed

Geravanchizadeh, Masoud; Fallah, Ali

2015-12-01

A binaural and psychoacoustically motivated intelligibility model, based on a well-known monaural microscopic model is proposed. This model simulates a phoneme recognition task in the presence of spatially distributed speech-shaped noise in anechoic scenarios. In the proposed model, binaural advantage effects are considered by generating a feature vector for a dynamic-time-warping speech recognizer. This vector consists of three subvectors incorporating two monaural subvectors to model the better-ear hearing, and a binaural subvector to simulate the binaural unmasking effect. The binaural unit of the model is based on equalization-cancellation theory. This model operates blindly, which means separate recordings of speech and noise are not required for the predictions. Speech intelligibility tests were conducted with 12 normal hearing listeners by collecting speech reception thresholds (SRTs) in the presence of single and multiple sources of speech-shaped noise. The comparison of the model predictions with the measured binaural SRTs, and with the predictions of a macroscopic binaural model called extended equalization-cancellation, shows that this approach predicts the intelligibility in anechoic scenarios with good precision. The square of the correlation coefficient (r(2)) and the mean-absolute error between the model predictions and the measurements are 0.98 and 0.62 dB, respectively.

Understanding speech when wearing communication headsets and hearing protectors with subband processing.

PubMed

Brammer, Anthony J; Yu, Gongqiang; Bernstein, Eric R; Cherniack, Martin G; Peterson, Donald R; Tufts, Jennifer B

2014-08-01

An adaptive, delayless, subband feed-forward control structure is employed to improve the speech signal-to-noise ratio (SNR) in the communication channel of a circumaural headset/hearing protector (HPD) from 90 Hz to 11.3 kHz, and to provide active noise control (ANC) from 50 to 800 Hz to complement the passive attenuation of the HPD. The task involves optimizing the speech SNR for each communication channel subband, subject to limiting the maximum sound level at the ear, maintaining a speech SNR preferred by users, and reducing large inter-band gain differences to improve speech quality. The performance of a proof-of-concept device has been evaluated in a pseudo-diffuse sound field when worn by human subjects under conditions of environmental noise and speech that do not pose a risk to hearing, and by simulation for other conditions. For the environmental noises employed in this study, subband speech SNR control combined with subband ANC produced greater improvement in word scores than subband ANC alone, and improved the consistency of word scores across subjects. The simulation employed a subject-specific linear model, and predicted that word scores are maintained in excess of 90% for sound levels outside the HPD of up to ∼115 dBA.

The sensitivity of hearing-impaired adults to acoustic attributes in simulated rooms.

PubMed

Whitmer, William M; McShefferty, David; Akeroyd, Michael A

2013-06-02

In previous studies we have shown that older hearing-impaired individuals are relatively insensitive to changes in the apparent width of broadband noises when those width changes were based on differences in interaural coherence [W. Whitmer, B. Seeber and M. Akeroyd, J. Acoust. Soc. Am. 132, 369-379 (2012)]. This insensitivity has been linked to senescent difficulties in resolving binaural fine-structure differences. It is therefore possible that interaural coherence, despite its widespread use, may not be the best acoustic surrogate of spatial perception for the aged and impaired. To test this, we simulated the room impulse responses for various acoustic scenarios with differing coherence and lateral (energy) fraction attributes using room modelling software (ODEON). Bilaterally impaired adult participants were asked to sketch the perceived size of speech tokens and musical excerpts that were convolved with these impulse responses and presented to them in a sound-dampened enclosure through a 24-loudspeaker array. Participants' binaural acuity was also measured using an interaural phase discrimination task. Corroborating our previous findings, the results showed less sensitivity to interaural coherence in the auditory source width judgments of older hearing-impaired individuals, indicating that alternate acoustic measurements in the design of spaces for the elderly may be necessary.

Adipose-derived stromal cells enhance auditory neuron survival in an animal model of sensory hearing loss.

PubMed

Schendzielorz, Philipp; Vollmer, Maike; Rak, Kristen; Wiegner, Armin; Nada, Nashwa; Radeloff, Katrin; Hagen, Rudolf; Radeloff, Andreas

2017-10-01

A cochlear implant (CI) is an electronic prosthesis that can partially restore speech perception capabilities. Optimum information transfer from the cochlea to the central auditory system requires a proper functioning auditory nerve (AN) that is electrically stimulated by the device. In deafness, the lack of neurotrophic support, normally provided by the sensory cells of the inner ear, however, leads to gradual degeneration of auditory neurons with undesirable consequences for CI performance. We evaluated the potential of adipose-derived stromal cells (ASCs) that are known to produce neurotrophic factors to prevent neural degeneration in sensory hearing loss. For this, co-cultures of ASCs with auditory neurons have been studied, and autologous ASC transplantation has been performed in a guinea pig model of gentamicin-induced sensory hearing loss. In vitro ASCs were neuroprotective and considerably increased the neuritogenesis of auditory neurons. In vivo transplantation of ASCs into the scala tympani resulted in an enhanced survival of auditory neurons. Specifically, peripheral AN processes that are assumed to be the optimal activation site for CI stimulation and that are particularly vulnerable to hair cell loss showed a significantly higher survival rate in ASC-treated ears. ASC transplantation into the inner ear may restore neurotrophic support in sensory hearing loss and may help to improve CI performance by enhanced AN survival. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Cortical Auditory Evoked Potentials Recorded From Nucleus Hybrid Cochlear Implant Users.

PubMed

Brown, Carolyn J; Jeon, Eun Kyung; Chiou, Li-Kuei; Kirby, Benjamin; Karsten, Sue A; Turner, Christopher W; Abbas, Paul J

2015-01-01

Nucleus Hybrid Cochlear Implant (CI) users hear low-frequency sounds via acoustic stimulation and high-frequency sounds via electrical stimulation. This within-subject study compares three different methods of coordinating programming of the acoustic and electrical components of the Hybrid device. Speech perception and cortical auditory evoked potentials (CAEP) were used to assess differences in outcome. The goals of this study were to determine whether (1) the evoked potential measures could predict which programming strategy resulted in better outcome on the speech perception task or was preferred by the listener, and (2) CAEPs could be used to predict which subjects benefitted most from having access to the electrical signal provided by the Hybrid implant. CAEPs were recorded from 10 Nucleus Hybrid CI users. Study participants were tested using three different experimental processor programs (MAPs) that differed in terms of how much overlap there was between the range of frequencies processed by the acoustic component of the Hybrid device and range of frequencies processed by the electrical component. The study design included allowing participants to acclimatize for a period of up to 4 weeks with each experimental program prior to speech perception and evoked potential testing. Performance using the experimental MAPs was assessed using both a closed-set consonant recognition task and an adaptive test that measured the signal-to-noise ratio that resulted in 50% correct identification of a set of 12 spondees presented in background noise. Long-duration, synthetic vowels were used to record both the cortical P1-N1-P2 "onset" response and the auditory "change" response (also known as the auditory change complex [ACC]). Correlations between the evoked potential measures and performance on the speech perception tasks are reported. Differences in performance using the three programming strategies were not large. Peak-to-peak amplitude of the ACC was not found to be sensitive enough to accurately predict the programming strategy that resulted in the best performance on either measure of speech perception. All 10 Hybrid CI users had residual low-frequency acoustic hearing. For all 10 subjects, allowing them to use both the acoustic and electrical signals provided by the implant improved performance on the consonant recognition task. For most subjects, it also resulted in slightly larger cortical change responses. However, the impact that listening mode had on the cortical change responses was small, and again, the correlation between the evoked potential and speech perception results was not significant. CAEPs can be successfully measured from Hybrid CI users. The responses that are recorded are similar to those recorded from normal-hearing listeners. The goal of this study was to see if CAEPs might play a role either in identifying the experimental program that resulted in best performance on a consonant recognition task or in documenting benefit from the use of the electrical signal provided by the Hybrid CI. At least for the stimuli and specific methods used in this study, no such predictive relationship was found.

Electric field with bipolar structure during magnetic reconnection without a guide field

NASA Astrophysics Data System (ADS)

Guo, Jun

2014-05-01

We present a study on the polarized electric field during the collisionless magnetic reconnection of antiparallel fields using two dimensional particle-in-cell simulations. The simulations demonstrate clearly that electron holes and electric field with bipolar structure are produced during magnetic reconnection without a guide field. The electric field with bipolar structure can be found near the X-line and on the separatrix and the plasma sheet boundary layer, which is consistent with the observations. These structures will elongate electron's time staying in the diffusion region. In addition, the electric fields with tripolar structures are also found in our simulation.

Basic Guidelines to Introduce Electric Circuit Simulation Software in a General Physics Course

ERIC Educational Resources Information Center

Moya, A. A.

2018-01-01

The introduction of electric circuit simulation software for undergraduate students in a general physics course is proposed in order to contribute to the constructive learning of electric circuit theory. This work focuses on the lab exercises based on dc, transient and ac analysis in electric circuits found in introductory physics courses, and…

Electric-car simulation

NASA Technical Reports Server (NTRS)

Chapman, C. P.; Slusser, R. A.

1980-01-01

PARAMET, interactive simulation program for parametric studies of electric vehicles, guides user through simulation by menu and series of prompts for input parameters. Program considers aerodynamic drag, rolling resistance, linear and rotational acceleration, and road gradient as forces acting on vehicle.

Equivalent threshold sound pressure levels (ETSPL) for Sennheiser HDA 280 supra-aural audiometric earphones in the frequency range 125 Hz to 8000 Hz.

PubMed

Poulsen, Torben; Oakley, Sebastian

2009-05-01

Hearing threshold sound pressure levels were measured for the Sennheiser HDA 280 audiometric earphone. Hearing thresholds were measured for 25 normal-hearing test subjects at the 11 audiometric test frequencies from 125 Hz to 8000 Hz. Sennheiser HDA 280 is a supra-aural earphone that may be seen as a substitute for the classical Telephonics TDH 39. The results are given as the equivalent threshold sound pressure level (ETSPL) measured in an acoustic coupler specified in IEC 60318-3. The results are in good agreement with an independent investigation from PTB, Braunschweig, Germany. From acoustic laboratory measurements ETSPL values are calculated for the ear simulator specified in IEC 60318-1. Fitting of earphone and coupler is discussed. The data may be used for a future update of the RETSPL standard for supra-aural audiometric earphones, ISO 389-1.

The Perception of Stress Pattern in Young Cochlear Implanted Children: An EEG Study.

PubMed

Vavatzanidis, Niki K; Mürbe, Dirk; Friederici, Angela D; Hahne, Anja

2016-01-01

Children with sensorineural hearing loss may (re)gain hearing with a cochlear implant-a device that transforms sounds into electric pulses and bypasses the dysfunctioning inner ear by stimulating the auditory nerve directly with an electrode array. Many implanted children master the acquisition of spoken language successfully, yet we still have little knowledge of the actual input they receive with the implant and specifically which language sensitive cues they hear. This would be important however, both for understanding the flexibility of the auditory system when presented with stimuli after a (life-) long phase of deprivation and for planning therapeutic intervention. In rhythmic languages the general stress pattern conveys important information about word boundaries. Infant language acquisition relies on such cues and can be severely hampered when this information is missing, as seen for dyslexic children and children with specific language impairment. Here we ask whether children with a cochlear implant perceive differences in stress patterns during their language acquisition phase and if they do, whether it is present directly following implant stimulation or if and how much time is needed for the auditory system to adapt to the new sensory modality. We performed a longitudinal ERP study, testing in bimonthly intervals the stress pattern perception of 17 young hearing impaired children (age range: 9-50 months; mean: 22 months) during their first 6 months of implant use. An additional session before the implantation served as control baseline. During a session they passively listened to an oddball paradigm featuring the disyllable "baba," which was stressed either on the first or second syllable (trochaic vs. iambic stress pattern). A group of age-matched normal hearing children participated as controls. Our results show, that within the first 6 months of implant use the implanted children develop a negative mismatch response for iambic but not for trochaic deviants, thus showing the same result as the normal hearing controls. Even congenitally deaf children show the same developing pattern. We therefore conclude (a) that young implanted children have early access to stress pattern information and (b) that they develop ERP responses similar to those of normal hearing children.

An Electroacoustic Hearing Protector Simulator That Accurately Predicts Pressure Levels in the Ear Based on Standard Performance Metrics

DTIC Science & Technology

2013-08-01

earplug and earmuff showing HPD simulator elements for energy flow paths...unprotected or protected ear traditionally start with analysis of energy flow through schematic diagrams based on electroacoustic (EA) analogies between...Schröter, 1983; Schröter and Pösselt, 1986; Shaw and Thiessen, 1958, 1962; Zwislocki, 1957). The analysis method tracks energy flow through fluid and

Numerical Computation of Electric Field and Potential Along Silicone Rubber Insulators Under Contaminated and Dry Band Conditions

NASA Astrophysics Data System (ADS)

Arshad; Nekahi, A.; McMeekin, S. G.; Farzaneh, M.

2016-09-01

Electrical field distribution along the insulator surface is considered one of the important parameters for the performance evaluation of outdoor insulators. In this paper numerical simulations were carried out to investigate the electric field and potential distribution along silicone rubber insulators under various polluted and dry band conditions. Simulations were performed using commercially available simulation package Comsol Multiphysics based on the finite element method. Various pollution severity levels were simulated by changing the conductivity of pollution layer. Dry bands of 2 cm width were inserted at the high voltage end, ground end, middle part, shed, sheath, and at the junction of shed and sheath to investigate the effect of dry band location and width on electric field and potential distribution. Partial pollution conditions were simulated by applying pollution layer on the top and bottom surface respectively. It was observed from the simulation results that electric field intensity was higher at the metal electrode ends and at the junction of dry bands. Simulation results showed that potential distribution is nonlinear in the case of clean and partially polluted insulator and linear for uniform pollution layer. Dry band formation effect both potential and electric field distribution. Power dissipated along the insulator surface and the resultant heat generation was also studied. The results of this study could be useful in the selection of polymeric insulators for contaminated environments.

Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

NASA Astrophysics Data System (ADS)

Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

2016-06-01

The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

Low-thrust solar electric propulsion navigation simulation program

NASA Technical Reports Server (NTRS)

Hagar, H. J.; Eller, T. J.

1973-01-01

An interplanetary low-thrust, solar electric propulsion mission simulation program suitable for navigation studies is presented. The mathematical models for trajectory simulation, error compensation, and tracking motion are described. The languages, input-output procedures, and subroutines are included.

Simulation Models for the Electric Power Requirements in a Guideway Transit System

DOT National Transportation Integrated Search

1980-04-01

This report describes a computer simulation model developed at the Transportation Systems Center to study the electrical power distribution characteristics of Automated Guideway Transit (AGT) systems. The objective of this simulation effort is to pro...

Effects of delayed treatment with combined GDNF and continuous electrical stimulation on spiral ganglion cell survival in deafened guinea pigs.

PubMed

Scheper, Verena; Paasche, Gerrit; Miller, Josef M; Warnecke, Athanasia; Berkingali, Nurdanat; Lenarz, Thomas; Stöver, Timo

2009-05-01

Electrical stimulation (ES) of spiral ganglion cells (SGC) via a cochlear implant is the standard treatment for profound sensor neural hearing loss. However, loss of hair cells as the morphological correlate of sensor neural hearing loss leads to deafferentation and death of SGC. Although immediate treatment with ES or glial cell line-derived neurotrophic factor (GDNF) can prevent degeneration of SGC, only few studies address the effectiveness of delayed treatment. We hypothesize that both interventions have a synergistic effect and that even delayed treatment would protect SGC. Therefore, an electrode connected to a pump was implanted into the left cochlea of guinea pigs 3 weeks after deafening. The contralateral untreated cochleae served as deafened intraindividual controls. Four groups were set up. Control animals received intracochlear infusion of artificial perilymph (AP/-). The experimental groups consisted of animals treated with AP in addition to continuous ES (AP/ES) or treated with GDNF alone (GDNF/-) or GDNF combined with continuous ES (GDNF/ES). Acoustically and electrically evoked auditory brain stem responses were recorded. All animals were killed 48 days after deafening; their cochleae were histologically evaluated. Survival of SGC increased significantly in the GDNF/- and AP/ES group compared with the AP/- group. A highly significant increase in SGC density was observed in the GDNF/ES group compared with the control group. Additionally, animals in the GDNF/ES group showed reduced EABR thresholds. Thus, delayed treatment with GDNF and ES can protect SGC from degeneration and may improve the benefits of cochlear implants.

A preliminary investigation of the air-bone gap: Changes in intracochlear sound pressure with air- and bone-conducted stimuli after cochlear implantation

PubMed Central

Banakis Hartl, Renee M.; Mattingly, Jameson K.; Greene, Nathaniel T.; Jenkins, Herman A.; Cass, Stephen P.; Tollin, Daniel J.

2016-01-01

Hypothesis A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion. Background Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative air-bone gap remains unexplained and could result in part from altered cochlear mechanics. Here, we sought to investigate changes to these mechanics via intracochlear pressure measurements before and after electrode implantation to quantify the contribution to postoperative air-bone gap. Methods Human cadaveric heads were implanted with titanium fixtures for bone conduction transducers. Velocities of stapes capitulum and cochlear promontory between the two windows were measured using single-axis laser Doppler vibrometry and fiber-optic sensors measured intracochlear pressures in scala vestibuli and tympani for air- and bone-conducted stimuli before and after cochlear implant electrode insertion through the round window. Results Intracochlear pressures revealed only slightly reduced responses to air-conducted stimuli consistent with prior literature. No significant changes were noted to bone-conducted stimuli after implantation. Velocities of the stapes capitulum and the cochlear promontory to both stimuli were stable following electrode placement. Conclusion Presence of a cochlear implant electrode causes alterations in intracochlear sound pressure levels to air, but not bone, conducted stimuli and helps to explain changes in residual hearing noted clinically. These results suggest the possibility of a cochlear conductive component to postoperative changes in hearing sensitivity. PMID:27579835

Spectrotemporal Modulation Detection and Speech Perception by Cochlear Implant Users

PubMed Central

Won, Jong Ho; Moon, Il Joon; Jin, Sunhwa; Park, Heesung; Woo, Jihwan; Cho, Yang-Sun; Chung, Won-Ho; Hong, Sung Hwa

2015-01-01

Spectrotemporal modulation (STM) detection performance was examined for cochlear implant (CI) users. The test involved discriminating between an unmodulated steady noise and a modulated stimulus. The modulated stimulus presents frequency modulation patterns that change in frequency over time. In order to examine STM detection performance for different modulation conditions, two different temporal modulation rates (5 and 10 Hz) and three different spectral modulation densities (0.5, 1.0, and 2.0 cycles/octave) were employed, producing a total 6 different STM stimulus conditions. In order to explore how electric hearing constrains STM sensitivity for CI users differently from acoustic hearing, normal-hearing (NH) and hearing-impaired (HI) listeners were also tested on the same tasks. STM detection performance was best in NH subjects, followed by HI subjects. On average, CI subjects showed poorest performance, but some CI subjects showed high levels of STM detection performance that was comparable to acoustic hearing. Significant correlations were found between STM detection performance and speech identification performance in quiet and in noise. In order to understand the relative contribution of spectral and temporal modulation cues to speech perception abilities for CI users, spectral and temporal modulation detection was performed separately and related to STM detection and speech perception performance. The results suggest that that slow spectral modulation rather than slow temporal modulation may be important for determining speech perception capabilities for CI users. Lastly, test–retest reliability for STM detection was good with no learning. The present study demonstrates that STM detection may be a useful tool to evaluate the ability of CI sound processing strategies to deliver clinically pertinent acoustic modulation information. PMID:26485715

The Effect of Residual Acoustic Hearing and Adaptation to Uncertainty on Speech Perception in Cochlear Implant Users: Evidence from Eye-Tracking

PubMed Central

McMurray, Bob; Farris-Trimble, Ashley; Seedorff, Michael; Rigler, Hannah

2015-01-01

Objectives While outcomes with cochlear implants (CIs) are generally good, performance can be fragile. The authors examined two factors that are crucial for good CI performance. First, while there is a clear benefit for adding residual acoustic hearing to CI stimulation (typically in low frequencies), it is unclear whether this contributes directly to phonetic categorization. Thus, the authors examined perception of voicing (which uses low-frequency acoustic cues) and fricative place of articulation (s/ʃ, which does not) in CI users with and without residual acoustic hearing. Second, in speech categorization experiments, CI users typically show shallower identification functions. These are typically interpreted as deriving from noisy encoding of the signal. However, psycholinguistic work suggests shallow slopes may also be a useful way to adapt to uncertainty. The authors thus employed an eye-tracking paradigm to examine this in CI users. Design Participants were 30 CI users (with a variety of configurations) and 22 age-matched normal hearing (NH) controls. Participants heard tokens from six b/p and six s/ʃ continua (eight steps) spanning real words (e.g., beach/peach, sip/ship). Participants selected the picture corresponding to the word they heard from a screen containing four items (a b-, p-, s- and ʃ-initial item). Eye movements to each object were monitored as a measure of how strongly they were considering each interpretation in the moments leading up to their final percept. Results Mouse-click results (analogous to phoneme identification) for voicing showed a shallower slope for CI users than NH listeners, but no differences between CI users with and without residual acoustic hearing. For fricatives, CI users also showed a shallower slope, but unexpectedly, acoustic + electric listeners showed an even shallower slope. Eye movements showed a gradient response to fine-grained acoustic differences for all listeners. Even considering only trials in which a participant clicked “b” (for example), and accounting for variation in the category boundary, participants made more looks to the competitor (“p”) as the voice onset time neared the boundary. CI users showed a similar pattern, but looked to the competitor more than NH listeners, and this was not different at different continuum steps. Conclusion Residual acoustic hearing did not improve voicing categorization suggesting it may not help identify these phonetic cues. The fact that acoustic + electric users showed poorer performance on fricatives was unexpected as they usually show a benefit in standardized perception measures, and as sibilants contain little energy in the low-frequency (acoustic) range. The authors hypothesize that these listeners may over-weight acoustic input, and have problems when this is not available (in fricatives). Thus, the benefit (or cost) of acoustic hearing for phonetic categorization may be complex. Eye movements suggest that in both CI and NH listeners, phoneme categorization is not a process of mapping continuous cues to discrete categories. Rather listeners preserve gradiency as a way to deal with uncertainty. CI listeners appear to adapt to their implant (in part) by amplifying competitor activation to preserve their flexibility in the face of potential misperceptions. PMID:26317298

Single and Multiple Microphone Noise Reduction Strategies in Cochlear Implants

PubMed Central

Azimi, Behnam; Hu, Yi; Friedland, David R.

2012-01-01

To restore hearing sensation, cochlear implants deliver electrical pulses to the auditory nerve by relying on sophisticated signal processing algorithms that convert acoustic inputs to electrical stimuli. Although individuals fitted with cochlear implants perform well in quiet, in the presence of background noise, the speech intelligibility of cochlear implant listeners is more susceptible to background noise than that of normal hearing listeners. Traditionally, to increase performance in noise, single-microphone noise reduction strategies have been used. More recently, a number of approaches have suggested that speech intelligibility in noise can be improved further by making use of two or more microphones, instead. Processing strategies based on multiple microphones can better exploit the spatial diversity of speech and noise because such strategies rely mostly on spatial information about the relative position of competing sound sources. In this article, we identify and elucidate the most significant theoretical aspects that underpin single- and multi-microphone noise reduction strategies for cochlear implants. More analytically, we focus on strategies of both types that have been shown to be promising for use in current-generation implant devices. We present data from past and more recent studies, and furthermore we outline the direction that future research in the area of noise reduction for cochlear implants could follow. PMID:22923425

A Comparison of Students' Conceptual Understanding of Electric Circuits in Simulation Only and Simulation-Laboratory Contexts

ERIC Educational Resources Information Center

Jaakkola, Tomi; Nurmi, Sami; Veermans, Koen

2011-01-01

The aim of this experimental study was to compare learning outcomes of students using a simulation alone (simulation environment) with outcomes of those using a simulation in parallel with real circuits (combination environment) in the domain of electricity, and to explore how learning outcomes in these environments are mediated by implicit (only…

Electric potential calculation in molecular simulation of electric double layer capacitors

NASA Astrophysics Data System (ADS)

Wang, Zhenxing; Olmsted, David L.; Asta, Mark; Laird, Brian B.

2016-11-01

For the molecular simulation of electric double layer capacitors (EDLCs), a number of methods have been proposed and implemented to determine the one-dimensional electric potential profile between the two electrodes at a fixed potential difference. In this work, we compare several of these methods for a model LiClO4-acetonitrile/graphite EDLC simulated using both the traditional fixed-charged method (FCM), in which a fixed charge is assigned a priori to the electrode atoms, or the recently developed constant potential method (CPM) (2007 J. Chem. Phys. 126 084704), where the electrode charges are allowed to fluctuate to keep the potential fixed. Based on an analysis of the full three-dimensional electric potential field, we suggest a method for determining the averaged one-dimensional electric potential profile that can be applied to both the FCM and CPM simulations. Compared to traditional methods based on numerically solving the one-dimensional Poisson’s equation, this method yields better accuracy and no supplemental assumptions.

Relationship of the interplanetary electric field to the high-latitude ionospheric electric field and currents Observations and model simulation

NASA Technical Reports Server (NTRS)

Clauer, C. R.; Banks, P. M.

1986-01-01

The electrical coupling between the solar wind, magnetosphere, and ionosphere is studied. The coupling is analyzed using observations of high-latitude ion convection measured by the Sondre Stromfjord radar in Greenland and a computer simulation. The computer simulation calculates the ionospheric electric potential distribution for a given configuration of field-aligned currents and conductivity distribution. The technique for measuring F-region in velocities at high time resolution over a large range of latitudes is described. Variations in the currents on ionospheric plasma convection are examined using a model of field-aligned currents linking the solar wind with the dayside, high-latitude ionosphere. The data reveal that high-latitude ionospheric convection patterns, electric fields, and field-aligned currents are dependent on IMF orientation; it is observed that the electric field, which drives the F-region plasma curve, responds within about 14 minutes to IMF variations in the magnetopause. Comparisons of the simulated plasma convection with the ion velocity measurements reveal good correlation between the data.

Troubleshooting Instruction in Vocational-Technical Education Via Dynamic Simulation. Final Report.

ERIC Educational Resources Information Center

Finch, Curtis R.

This study was designed to examine the feasibility of using simulation as a means of teaching vocational-technical students to detect and identify malfunctions in selected electrical and mechanical systems. A dynamic simulator was employed which features interchangeable panels and logic that permits the simulation of electrical or mechanical…

Design and Development of a 200-kW Turbo-Electric Distributed Propulsion Testbed

NASA Technical Reports Server (NTRS)

Papathakis, Kurt V.; Kloesel, Kurt J.; Lin, Yohan; Clarke, Sean; Ediger, Jacob J.; Ginn, Starr

2016-01-01

The National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center (AFRC) (Edwards, California) is developing a Hybrid-Electric Integrated Systems Testbed (HEIST) Testbed as part of the HEIST Project, to study power management and transition complexities, modular architectures, and flight control laws for turbo-electric distributed propulsion technologies using representative hardware and piloted simulations. Capabilities are being developed to assess the flight readiness of hybrid electric and distributed electric vehicle architectures. Additionally, NASA will leverage experience gained and assets developed from HEIST to assist in flight-test proposal development, flight-test vehicle design, and evaluation of hybrid electric and distributed electric concept vehicles for flight safety. The HEIST test equipment will include three trailers supporting a distributed electric propulsion wing, a battery system and turbogenerator, dynamometers, and supporting power and communication infrastructure, all connected to the AFRC Core simulation. Plans call for 18 high performance electric motors that will be powered by batteries and the turbogenerator, and commanded by a piloted simulation. Flight control algorithms will be developed on the turbo-electric distributed propulsion system.

The benefits of hearing aids and closed captioning for television viewing by older adults with hearing loss.

PubMed

Gordon-Salant, Sandra; Callahan, Julia S

2009-08-01

Although watching television is a common leisure activity of older adults, the ability to understand televised speech may be compromised by age-related hearing loss. Two potential assistive devices for improving television viewing are hearing aids (HAs) and closed captioning (CC), but their use and benefit by older adults with hearing loss are unknown. The primary purpose of this initial investigation was to determine if older hearing-impaired adults show improvements in understanding televised speech with the use of these two assistive devices (HAs and CC) compared with conditions without these devices. A secondary purpose was to examine the frequency of HA and CC use among a sample of older HA wearers. The investigation entailed a randomized, repeated-measures design of 15 older adults (59 to 82 yr) with bilateral sensorineural hearing losses who wore HAs. Participants viewed three types of televised programs (news, drama, and game show) that were each edited into lists of speech segments and provided an identification response. Each participant was tested in four conditions: baseline (no HA or CC), HA only, CC only, and HA + CC. Also, pilot testing with young normal-hearing listeners was conducted to establish list equivalence and stimulus intelligibility with a control group. All testing was conducted in a quiet room to simulate a living room, using a 20 in flat screen television. Questionnaires were also administered to participants to determine the frequency of HA and CC use while watching television. A significant effect of viewing condition was observed for all programs. Participants exhibited significantly better speech recognition scores in conditions with CC than those without CC (p < 0.01). Use of personal HAs did not significantly improve recognition of televised speech compared with the unaided condition. The condition effect was similar across the three different programs. Most of the participants (73%) regularly wore their HAs while watching television; very few of them (13%) had ever used CC. On average, use of CC while watching television dramatically improved speech understanding by a sample of older hearing-impaired adults compared with conditions without CC, including when HAs were worn.

Camera Traps Can Be Heard and Seen by Animals

PubMed Central

Meek, Paul D.; Ballard, Guy-Anthony; Fleming, Peter J. S.; Schaefer, Michael; Williams, Warwick; Falzon, Greg

2014-01-01

Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5) and infrared illumination outputs (n = 7) of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21) and assessed the vision ranges (n = 3) of mammals species (where data existed) to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals’ hearing and produce illumination that can be seen by many species. PMID:25354356

Speaker recognition with temporal cues in acoustic and electric hearing

NASA Astrophysics Data System (ADS)

Vongphoe, Michael; Zeng, Fan-Gang

2005-08-01

Natural spoken language processing includes not only speech recognition but also identification of the speaker's gender, age, emotional, and social status. Our purpose in this study is to evaluate whether temporal cues are sufficient to support both speech and speaker recognition. Ten cochlear-implant and six normal-hearing subjects were presented with vowel tokens spoken by three men, three women, two boys, and two girls. In one condition, the subject was asked to recognize the vowel. In the other condition, the subject was asked to identify the speaker. Extensive training was provided for the speaker recognition task. Normal-hearing subjects achieved nearly perfect performance in both tasks. Cochlear-implant subjects achieved good performance in vowel recognition but poor performance in speaker recognition. The level of the cochlear implant performance was functionally equivalent to normal performance with eight spectral bands for vowel recognition but only to one band for speaker recognition. These results show a disassociation between speech and speaker recognition with primarily temporal cues, highlighting the limitation of current speech processing strategies in cochlear implants. Several methods, including explicit encoding of fundamental frequency and frequency modulation, are proposed to improve speaker recognition for current cochlear implant users.

Rate and onset cues can improve cochlear implant synthetic vowel recognition in noise

PubMed Central

Mc Laughlin, Myles; Reilly, Richard B.; Zeng, Fan-Gang

2013-01-01

Understanding speech-in-noise is difficult for most cochlear implant (CI) users. Speech-in-noise segregation cues are well understood for acoustic hearing but not for electric hearing. This study investigated the effects of stimulation rate and onset delay on synthetic vowel-in-noise recognition in CI subjects. In experiment I, synthetic vowels were presented at 50, 145, or 795 pulse/s and noise at the same three rates, yielding nine combinations. Recognition improved significantly if the noise had a lower rate than the vowel, suggesting that listeners can use temporal gaps in the noise to detect a synthetic vowel. This hypothesis is supported by accurate prediction of synthetic vowel recognition using a temporal integration window model. Using lower rates a similar trend was observed in normal hearing subjects. Experiment II found that for CI subjects, a vowel onset delay improved performance if the noise had a lower or higher rate than the synthetic vowel. These results show that differing rates or onset times can improve synthetic vowel-in-noise recognition, indicating a need to develop speech processing strategies that encode or emphasize these cues. PMID:23464025

[Communication and noise. Speech intelligibility of airplane pilots with and without active noise compensation].

PubMed

Matschke, R G

1994-08-01

Noise exposure measurements were performed with pilots of the German Federal Navy during flight situations. The ambient noise levels during regular flight were maintained at levels above a 90 dB A-weighted level. This noise intensity requires wearing ear protection to avoid sound-induced hearing loss. To be able to understand radio communication (ATC) in spite of a noisy environment, headphone volume must be raised above the noise of the engines. The use of ear plugs in addition to the headsets and flight helmets is only of limited value because personal ear protection affects the intelligibility of ATC. Whereas speech intelligibility of pilots with normal hearing is affected to only a smaller degree, pilots with pre-existing high-frequency hearing losses show substantial impairments of speech intelligibility that vary in proportion to the hearing deficit present. Communication abilities can be reduced drastically, which in turn can affect air traffic security. The development of active noise compensation devices (ANC) that make use of the "anti-noise" principle may be a solution to this dilemma. To evaluate the effectiveness of an ANC-system and its influence on speech intelligibility, speech audiometry was performed with a German standardized test during simulated flight conditions with helicopter pilots. Results demonstrate the helpful effect on speech understanding especially for pilots with noise-induced hearing losses. This may help to avoid pre-retirement professional disability.

Nursing students' knowledge of and performance in communicating with patients with hearing impairment.

PubMed

Adib-Hajbaghery, Mohsen; Rezaei-Shahsavarloo, Zahra

2015-04-01

The present study aimed to investigate nursing students' knowledge of and performance in communicating with patients with hearing impairment. A cross-sectional study was conducted on all senior nursing students (n = 71) in a nursing school in Iran in 2013. Data collection was performed with a demographics questionnaire, knowledge questionnaire, and performance assessment checklist. Two stages were designed to evaluate the students. In the first stage, students conducted an interview with a simulated patient with hearing impairment who experienced chest pain. In the second stage, students answered the knowledge questionnaire. Descriptive statistics, independent sample Student's t-test, and Pearson correlation coefficient were used to analyze the data. In total, 11.3% of participants had a history of caring for a patient with hearing impairment. The majority of students evaluated their performance in communicating with such patients at a moderate level. A significant difference was observed between the mean score of knowledge in men and women (P = 0.05), and male students gained higher scores. In total, 61.5% of the students had low to very low levels of knowledge and 87.3% of them had weak to very weak performance in communicating with patients with hearing impairment. Nursing students are lacking in knowledge and skills required for effective communication with patients with hearing impairment. Nurse educators should pay more attention to this issue as it is their responsibility to prepare nurses who are competent to deal with common issues they will face in practice. © 2014 The Authors. Japan Journal of Nursing Science © 2014 Japan Academy of Nursing Science.

Simulation of switching overvoltages in the mine electric power supply system

NASA Astrophysics Data System (ADS)

Ivanchenko, D. I.; Novozhilov, N. G.

2017-02-01

Overvoltages occur in mine power supply systems during switching off consumers with high inductive load, such as transformers, reactors and electrical machines. Overvoltages lead to an increase of insulation degradation rate and may cause electric faults, power outage, fire and explosion of methane and coal dust. This paper is dedicated to simulation of vacuum circuit breaker switching overvoltages in a mine power supply system by means of Simulink MATLAB. The model of the vacuum circuit breaker implements simulation of transient recovery voltage, current chopping and an electric arc. Obtained results were compared to available experimental data.

Performance of Electric Double-Layer Capacitor Simulators

NASA Astrophysics Data System (ADS)

Funabiki, Shigeyuki; Kodama, Shinsuke; Yamamoto, Masayoshi

This paper proposes a simulator of EDLC, which realizes the performance equivalent to electric double-layer capacitors (EDLCs). The proposed simulator consists of an electrolytic capacitor and a two-quadrant chopper working as a current source. Its operation principle is described in the first place. The voltage dependence of capacitance of EDLCs is taken into account. The performance of the proposed EDLC simulator is verified by computer simulations.

Electric-hybrid-vehicle simulation

NASA Astrophysics Data System (ADS)

Pasma, D. C.

The simulation of electric hybrid vehicles is to be performed using experimental data to model propulsion system components. The performance of an existing ac propulsion system will be used as the baseline for comparative purposes. Hybrid components to be evaluated include electrically and mechanically driven flywheels, and an elastomeric regenerative braking system.

Voice gender identification by cochlear implant users: The role of spectral and temporal resolution

NASA Astrophysics Data System (ADS)

Fu, Qian-Jie; Chinchilla, Sherol; Nogaki, Geraldine; Galvin, John J.

2005-09-01

The present study explored the relative contributions of spectral and temporal information to voice gender identification by cochlear implant users and normal-hearing subjects. Cochlear implant listeners were tested using their everyday speech processors, while normal-hearing subjects were tested under speech processing conditions that simulated various degrees of spectral resolution, temporal resolution, and spectral mismatch. Voice gender identification was tested for two talker sets. In Talker Set 1, the mean fundamental frequency values of the male and female talkers differed by 100 Hz while in Talker Set 2, the mean values differed by 10 Hz. Cochlear implant listeners achieved higher levels of performance with Talker Set 1, while performance was significantly reduced for Talker Set 2. For normal-hearing listeners, performance was significantly affected by the spectral resolution, for both Talker Sets. With matched speech, temporal cues contributed to voice gender identification only for Talker Set 1 while spectral mismatch significantly reduced performance for both Talker Sets. The performance of cochlear implant listeners was similar to that of normal-hearing subjects listening to 4-8 spectral channels. The results suggest that, because of the reduced spectral resolution, cochlear implant patients may attend strongly to periodicity cues to distinguish voice gender.

DSL prescriptive targets for bone conduction devices: adaptation and comparison to clinical fittings.

PubMed

Hodgetts, William E; Scollie, Susan D

2017-07-01

To develop an algorithm that prescribes targets for bone conduction frequency response shape, compression, and output limiting, along with a clinical method that ensures accurate transforms between assessment and verification stages of the clinical workflow. Technical report of target generation and validation. We recruited 39 adult users of unilateral percutaneous bone conduction hearing aids with a range of unilateral, bilateral, mixed and conductive hearing losses across the sample. The initial algorithm over-prescribed output compared to the user's own settings in the low frequencies, but provided a good match to user settings in the high frequencies. Corrections to the targets were derived and implemented as a low-frequency cut aimed at improving acceptance of the wearer's own voice during device use. The DSL-BCD prescriptive algorithm is compatible with verification of devices and fine-tuning to target for percutaneous bone conduction hearing devices that can be coupled to a skull simulator. Further study is needed to investigate the appropriateness of this prescriptive algorithm for other input levels, and for other clinical populations including those with single-sided deafness, bilateral devices, children and users of transcutaneous bone conduction hearing aids.

Adaptive spatial filtering improves speech reception in noise while preserving binaural cues.

PubMed

Bissmeyer, Susan R S; Goldsworthy, Raymond L

2017-09-01

Hearing loss greatly reduces an individual's ability to comprehend speech in the presence of background noise. Over the past decades, numerous signal-processing algorithms have been developed to improve speech reception in these situations for cochlear implant and hearing aid users. One challenge is to reduce background noise while not introducing interaural distortion that would degrade binaural hearing. The present study evaluates a noise reduction algorithm, referred to as binaural Fennec, that was designed to improve speech reception in background noise while preserving binaural cues. Speech reception thresholds were measured for normal-hearing listeners in a simulated environment with target speech generated in front of the listener and background noise originating 90° to the right of the listener. Lateralization thresholds were also measured in the presence of background noise. These measures were conducted in anechoic and reverberant environments. Results indicate that the algorithm improved speech reception thresholds, even in highly reverberant environments. Results indicate that the algorithm also improved lateralization thresholds for the anechoic environment while not affecting lateralization thresholds for the reverberant environments. These results provide clear evidence that this algorithm can improve speech reception in background noise while preserving binaural cues used to lateralize sound.

COMSOL based Simulation on the Effect of Electric Field changes due to Lightning on Ground

NASA Astrophysics Data System (ADS)

Premlet, B.; Joby, N. E.; Sabu, S.

2017-12-01

The phenomenon of lightning is accompanied by localised changes in atmospheric electric fields. In cloud-to-ground strike locations, changes in atmospheric electric fields can even be observed at the ground a few minutes prior to a strike. A lot of research has been done already on the electrostatic changes prior to lightning in the region above ground. Through this work, we investigate into the effects of lightning electric fields on/under ground with the aid of simulations done in COMSOL Multiphysics. Horizontal and vertical profiles of voltage gradient, electric field, polarisation etc. are investigated. Simulation experiments were conducted using a general model of lightning electric fields formed using data recorded by the Electric Field Mills(EFMs) from three diverse parts of the world- Kennedy Space Centre (KSC),Florida (Using GHRC datasets),Sonnblick Observatory, Austria and National Centre for Earth Science Studies Trivandrum (NCESS),India. COMSOL models of the global electric circuit were developed using Sandstone as the base model for ground. Similar works in literature have only dealt with lightning electric fields above the ground. This work is the first step towards a high-level simulation on the effects of atmospheric electric field on/below ground. The results of this simulation work can aid lightning forecasting and preparedness by opening new doors for voltage based prediction methods at ground. It is also a tool to understand phenomena such as fulgurites, corona effect etc. It also helps in the design of buried cables and improved grounding systems. This work can also be a first step towards understanding localised potential variations at the ground during lightning.

Speech Perception in Tones and Noise via Cochlear Implants Reveals Influence of Spectral Resolution on Temporal Processing

PubMed Central

Kreft, Heather A.

2014-01-01

Under normal conditions, human speech is remarkably robust to degradation by noise and other distortions. However, people with hearing loss, including those with cochlear implants, often experience great difficulty in understanding speech in noisy environments. Recent work with normal-hearing listeners has shown that the amplitude fluctuations inherent in noise contribute strongly to the masking of speech. In contrast, this study shows that speech perception via a cochlear implant is unaffected by the inherent temporal fluctuations of noise. This qualitative difference between acoustic and electric auditory perception does not seem to be due to differences in underlying temporal acuity but can instead be explained by the poorer spectral resolution of cochlear implants, relative to the normally functioning ear, which leads to an effective smoothing of the inherent temporal-envelope fluctuations of noise. The outcome suggests an unexpected trade-off between the detrimental effects of poorer spectral resolution and the beneficial effects of a smoother noise temporal envelope. This trade-off provides an explanation for the long-standing puzzle of why strong correlations between speech understanding and spectral resolution have remained elusive. The results also provide a potential explanation for why cochlear-implant users and hearing-impaired listeners exhibit reduced or absent masking release when large and relatively slow temporal fluctuations are introduced in noise maskers. The multitone maskers used here may provide an effective new diagnostic tool for assessing functional hearing loss and reduced spectral resolution. PMID:25315376

Simulated effect of pneumococcal vaccination in the Netherlands on existing rules constructed in a non-vaccinated cohort predicting sequelae after bacterial meningitis

PubMed Central

2010-01-01

Background Previously two prediction rules identifying children at risk of hearing loss and academic or behavioral limitations after bacterial meningitis were developed. Streptococcus pneumoniae as causative pathogen was an important risk factor in both. Since 2006 Dutch children receive seven-valent conjugate vaccination against S. pneumoniae. The presumed effect of vaccination was simulated by excluding all children infected by S. pneumoniae with the serotypes included in the vaccine, from both previous collected cohorts (between 1990-1995). Methods Children infected by one of the vaccine serotypes were excluded from both original cohorts (hearing loss: 70 of 628 children; academic or behavioral limitations: 26 of 182 children). All identified risk factors were included in multivariate logistic regression models. The discriminative ability of both new models was calculated. Results The same risk factors as in the original models were significant. The discriminative ability of the original hearing loss model was 0.84 and of the new model 0.87. In the academic or behavioral limitations model it was 0.83 and 0.84 respectively. Conclusion It can be assumed that the prediction rules will also be applicable on a vaccinated population. However, vaccination does not provide 100% coverage and evidence is available that serotype replacement will occur. The impact of vaccination on serotype replacement needs to be investigated, and the prediction rules must be validated externally. PMID:20815866

Analysis of audiometric notch as a noise-induced hearing loss phenotype in US youth: data from the National Health And Nutrition Examination Survey, 2005-2010.

PubMed

Bhatt, Ishan S; Guthrie, O'neil

2017-06-01

Bilateral audiometric notch (BN) at 4000-6000 Hz was identified as a noise-induced hearing loss (NIHL) phenotype for genetic association analysis in college-aged musicians. This study analysed BN in a sample of US youth. Prevalence of the BN within the study sample was determined and logistic-regression analyses were performed to identify audiologic and other demographic factors associated with BN. Computer-simulated "flat" audiograms were used to estimate potential influence of false-positive rates in estimating the prevalence of the BN. 2348 participants (12-19 years) following the inclusion criteria were selected from the National Health and Nutrition Examination Survey data (2005-2010). The prevalence of BN was 16.6%. Almost 55.6% of the participants showed notch in at least one ear. Noise exposure, gender, ethnicity and age showed significant relationship with the BN. Computer simulation revealed that 5.5% of simulated participants with "flat" audiograms showed BN. Association of noise exposure with BN suggests that it is a useful NIHL phenotype for genetic association analyses. However, further research is necessary to reduce false-positive rates in notch identification.

Perception of speech in reverberant conditions using AM-FM cochlear implant simulation.

PubMed

Drgas, Szymon; Blaszak, Magdalena A

2010-10-01

This study assessed the effects of speech misidentification and cognitive processing errors in normal-hearing adults listening to degraded auditory input signals simulating cochlear implants in reverberation conditions. Three variables were controlled: number of vocoder channels (six and twelve), instantaneous frequency change rate (none, 50, 400 Hz), and enclosures (different reverberation conditions). The analyses were made on the basis of: (a) nonsense word recognition scores for eight young normal-hearing listeners, (b) 'ease of listening' based on the time of response, and (c) the subjective measure of difficulty. The maximum score of speech intelligibility in cochlear implant simulation was 70% for non-reverberant conditions with a 12-channel vocoder and changes of instantaneous frequency limited to 400 Hz. In the presence of reflections, word misidentification was about 10-20 percentage points higher. There was little difference between the 50 and 400 Hz frequency modulation cut-off for the 12-channel vocoder; however, in the case of six channels this difference was more significant. The results of the experiment suggest that the information other than F0, that is carried by FM, can be sufficient to improve speech intelligibility in the real-world conditions.

Estimates of olivine-basaltic melt electrical conductivity using a digital rock physics approach

NASA Astrophysics Data System (ADS)

Miller, Kevin J.; Montési, Laurent G. J.; Zhu, Wen-lu

2015-12-01

Estimates of melt content beneath fast-spreading mid-ocean ridges inferred from magnetotelluric tomography (MT) vary between 0.01 and 0.10. Much of this variation may stem from a lack of understanding of how the grain-scale melt geometry influences the bulk electrical conductivity of a partially molten rock, especially at low melt fraction. We compute bulk electrical conductivity of olivine-basalt aggregates over 0.02 to 0.20 melt fraction by simulating electric current in experimentally obtained partially molten geometries. Olivine-basalt aggregates were synthesized by hot-pressing San Carlos olivine and high-alumina basalt in a solid-medium piston-cylinder apparatus. Run conditions for experimental charges were 1.5 GPa and 1350 °C. Upon completion, charges were quenched and cored. Samples were imaged using synchrotron X-ray micro-computed tomography (μ-CT). The resulting high-resolution, 3-dimensional (3-D) image of the melt distribution constitutes a digital rock sample, on which numerical simulations were conducted to estimate material properties. To compute bulk electrical conductivity, we simulated a direct current measurement by solving the current continuity equation, assuming electrical conductivities for olivine and melt. An application of Ohm's Law yields the bulk electrical conductivity of the partially molten region. The bulk electrical conductivity values for nominally dry materials follow a power-law relationship σbulk = Cσmeltϕm with fit parameters m = 1.3 ± 0.3 and C = 0.66 ± 0.06. Laminar fluid flow simulations were conducted on the same partially molten geometries to obtain permeability, and the respective pathways for electrical current and fluid flow over the same melt geometry were compared. Our results indicate that the pathways for flow fluid are different from those for electric current. Electrical tortuosity is lower than fluid flow tortuosity. The simulation results are compared to existing experimental data, and the potential influence of volatiles and melt films on electrical conductivity of partially molten rocks is discussed.

Simulation and energy analysis of distributed electric heating system

NASA Astrophysics Data System (ADS)

Yu, Bo; Han, Shenchao; Yang, Yanchun; Liu, Mingyuan

2018-02-01

Distributed electric heating system assistssolar heating systemby using air-source heat pump. Air-source heat pump as auxiliary heat sourcecan make up the defects of the conventional solar thermal system can provide a 24 - hour high - efficiency work. It has certain practical value and practical significance to reduce emissions and promote building energy efficiency. Using Polysun software the system is simulated and compared with ordinary electric boiler heating system. The simulation results show that upon energy request, 5844.5kW energy is saved and 3135kg carbon - dioxide emissions are reduced and5844.5 kWhfuel and energy consumption is decreased with distributed electric heating system. Theeffect of conserving energy and reducing emissions using distributed electric heating systemis very obvious.

A NEW TECHNIQUE FOR THE PHOTOSPHERIC DRIVING OF NON-POTENTIAL SOLAR CORONAL MAGNETIC FIELD SIMULATIONS

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

Weinzierl, Marion; Yeates, Anthony R.; Mackay, Duncan H.

2016-05-20

In this paper, we develop a new technique for driving global non-potential simulations of the Sun’s coronal magnetic field solely from sequences of radial magnetic maps of the solar photosphere. A primary challenge to driving such global simulations is that the required horizontal electric field cannot be uniquely determined from such maps. We show that an “inductive” electric field solution similar to that used by previous authors successfully reproduces specific features of the coronal field evolution in both single and multiple bipole simulations. For these cases, the true solution is known because the electric field was generated from a surfacemore » flux-transport model. The match for these cases is further improved by including the non-inductive electric field contribution from surface differential rotation. Then, using this reconstruction method for the electric field, we show that a coronal non-potential simulation can be successfully driven from a sequence of ADAPT maps of the photospheric radial field, without including additional physical observations which are not routinely available.« less

High Level Impulse Sounds and Human Hearing: Standards, Physiology, Quantification

DTIC Science & Technology

2012-05-01

a result of this change the piston-like movements of the stapes are replaced by a tilting action, which is much less effective in pushing cochlear ...Above this threshold, high noise levels result in a turbulent flow of air through the nonlinear element of the protector, effectively dissipating the...electrical diagrams of earplug and earmuff models (Kalb, 2011). In the model shown, the energy flow through the HPD propagates along three parallel

Sampling the Deaf Experience.

ERIC Educational Resources Information Center

Teller, Henry E.; And Others

1993-01-01

Two graduate students in deaf education wore ear plugs for two months to simulate hearing loss, and recorded their experiences and feelings. Excerpts from their journals are presented, commenting on such daily activities as shopping at a mall, watching television, driving, babysitting, and attending a football game. (JDD)

Gender and speaker identification as a function of the number of channels in spectrally reduced speech

NASA Astrophysics Data System (ADS)

Gonzalez, Julio; Oliver, Juan C.

2005-07-01

Considerable research on speech intelligibility for cochlear-implant users has been conducted using acoustic simulations with normal-hearing subjects. However, some relevant topics about perception through cochlear implants remain scantly explored. The present study examined the perception by normal-hearing subjects of gender and identity of a talker as a function of the number of channels in spectrally reduced speech. Two simulation strategies were compared. They were implemented by two different processors that presented signals as either the sum of sine waves at the center of the channels or as the sum of noise bands. In Experiment 1, 15 subjects determined the gender of 40 talkers (20 males + 20 females) from a natural utterance processed through 3, 4, 5, 6, 8, 10, 12, and 16 channels with both processors. In Experiment 2, 56 subjects matched a natural sentence uttered by 10 talkers with the corresponding simulation replicas processed through 3, 4, 8, and 16 channels for each processor. In Experiment 3, 72 subjects performed the same task but different sentences were used for natural and processed stimuli. A control Experiment 4 was conducted to equate the processing steps between the two simulation strategies. Results showed that gender and talker identification was better for the sine-wave processor, and that performance through the noise-band processor was more sensitive to the number of channels. Implications and possible explanations for the superiority of sine-wave simulations are discussed.

Method of imaging the electrical conductivity distribution of a subsurface

DOEpatents

Johnson, Timothy C.

2017-09-26

A method of imaging electrical conductivity distribution of a subsurface containing metallic structures with known locations and dimensions is disclosed. Current is injected into the subsurface to measure electrical potentials using multiple sets of electrodes, thus generating electrical resistivity tomography measurements. A numeric code is applied to simulate the measured potentials in the presence of the metallic structures. An inversion code is applied that utilizes the electrical resistivity tomography measurements and the simulated measured potentials to image the subsurface electrical conductivity distribution and remove effects of the subsurface metallic structures with known locations and dimensions.

ERP evidence for the recognition of emotional prosody through simulated cochlear implant strategies.

PubMed

Agrawal, Deepashri; Timm, Lydia; Viola, Filipa Campos; Debener, Stefan; Büchner, Andreas; Dengler, Reinhard; Wittfoth, Matthias

2012-09-20

Emotionally salient information in spoken language can be provided by variations in speech melody (prosody) or by emotional semantics. Emotional prosody is essential to convey feelings through speech. In sensori-neural hearing loss, impaired speech perception can be improved by cochlear implants (CIs). Aim of this study was to investigate the performance of normal-hearing (NH) participants on the perception of emotional prosody with vocoded stimuli. Semantically neutral sentences with emotional (happy, angry and neutral) prosody were used. Sentences were manipulated to simulate two CI speech-coding strategies: the Advance Combination Encoder (ACE) and the newly developed Psychoacoustic Advanced Combination Encoder (PACE). Twenty NH adults were asked to recognize emotional prosody from ACE and PACE simulations. Performance was assessed using behavioral tests and event-related potentials (ERPs). Behavioral data revealed superior performance with original stimuli compared to the simulations. For simulations, better recognition for happy and angry prosody was observed compared to the neutral. Irrespective of simulated or unsimulated stimulus type, a significantly larger P200 event-related potential was observed for happy prosody after sentence onset than the other two emotions. Further, the amplitude of P200 was significantly more positive for PACE strategy use compared to the ACE strategy. Results suggested P200 peak as an indicator of active differentiation and recognition of emotional prosody. Larger P200 peak amplitude for happy prosody indicated importance of fundamental frequency (F0) cues in prosody processing. Advantage of PACE over ACE highlighted a privileged role of the psychoacoustic masking model in improving prosody perception. Taken together, the study emphasizes on the importance of vocoded simulation to better understand the prosodic cues which CI users may be utilizing.

Near-field marking of gold nanostars by ultrashort pulsed laser irradiation: experiment and simulations

NASA Astrophysics Data System (ADS)

Møller, Søren H.; Vester-Petersen, Joakim; Nazir, Adnan; Eriksen, Emil H.; Julsgaard, Brian; Madsen, Søren P.; Balling, Peter

2018-02-01

Quantitative measurements of the electric near-field distribution of star-shaped gold nanoparticles have been performed by femtosecond laser ablation. Measurements were carried out on and off the plasmon resonance. A detailed comparison with numerical simulations of the electric fields is presented. Semi-quantitative agreement is found, with slight systematic differences between experimentally observed and simulated near-field patterns close to strong electric-field gradients. The deviations are attributed to carrier transport preceding ablation.

Pricing and Application of Electric Storage

NASA Astrophysics Data System (ADS)

Zhao, Jialin

Electric storage provides a vehicle to store power for future use. It contributes to the grids in multiple aspects. For instance, electric storage is a more effective approach to provide electricity ancillary services than conventional methods. Additionally, electric storage, especially fast-responding units, allows owners to implement high-frequency power transactions in settings such as the 5-min real-time trading market. Such high-frequency power trades were limited in the past. However, as technology advances, the power markets have evolved. For instance, the California Independent System Operator now supports the 5-min real-time trading and the hourly day-ahead ancillary services bidding. Existing valuation models of electric storage were not designed to accommodate these recent market developments. To fill this gap, I focus on the fast-responding grid-level electric storage that provides both the real-time trading and the day-ahead ancillary services bidding. To evaluate such an asset, I propose a Monte Carlo Simulation-based valuation model. The foundation of my model is simulations of power prices. This study develops a new simulation model of electric prices. It is worth noting that, unlike existing models, my proposed simulation model captures the dependency of the real-time markets on the day-ahead markets. Upon such simulations, this study investigates the pricing and the application of electric storage at a 5-min granularity. Essentially, my model is a Dynamic Programming system with both endogenous variables (i.e., the State-of-Charge of electric storage) and exogenous variables (i.e., power prices). My first numerical example is the valuation of a fictitious 4MWh battery. Similarly, my second example evaluates the application of two units of 2MWh batteries. By comparing these two experiments, I investigate the issues related to battery configurations, such as the impacts of splitting storage capability on the valuation of electric storage.

Modeling and simulation of deformation of hydrogels responding to electric stimulus.

PubMed

Li, Hua; Luo, Rongmo; Lam, K Y

2007-01-01

A model for simulation of pH-sensitive hydrogels is refined in this paper to extend its application to electric-sensitive hydrogels, termed the refined multi-effect-coupling electric-stimulus (rMECe) model. By reformulation of the fixed-charge density and consideration of finite deformation, the rMECe model is able to predict the responsive deformations of the hydrogels when they are immersed in a bath solution subject to externally applied electric field. The rMECe model consists of nonlinear partial differential governing equations with chemo-electro-mechanical coupling effects and the fixed-charge density with electric-field effect. By comparison between simulation and experiment extracted from literature, the model is verified to be accurate and stable. The rMECe model performs quantitatively for deformation analysis of the electric-sensitive hydrogels. The influences of several physical parameters, including the externally applied electric voltage, initial fixed-charge density, hydrogel strip thickness, ionic strength and valence of surrounding solution, are discussed in detail on the displacement and average curvature of the hydrogels.

The Effects of Simulated Hearing Loss on Simultaneous Speech Recognition and Walking Navigation Tasks

DTIC Science & Technology

2013-02-01

and ear impedance testing, respectively. Normality of vestibular function was assessed by asking the participants about any cases of chronic vertigo ...none) and observing participant behavior during the ODT walking training session. Two potential participants incurred light vertigo during ODT

An electrical circuit model for simulation of indoor radon concentration.

PubMed

Musavi Nasab, S M; Negarestani, A

2013-01-01

In this study, a new model based on electric circuit theory was introduced to simulate the behaviour of indoor radon concentration. In this model, a voltage source simulates radon generation in walls, conductivity simulates migration through walls and voltage across a capacitor simulates radon concentration in a room. This simulation considers migration of radon through walls by diffusion mechanism in one-dimensional geometry. Data reported in a typical Greek house were employed to examine the application of this technique of simulation to the behaviour of radon.

Speedup computation of HD-sEMG signals using a motor unit-specific electrical source model.

PubMed

Carriou, Vincent; Boudaoud, Sofiane; Laforet, Jeremy

2018-01-23

Nowadays, bio-reliable modeling of muscle contraction is becoming more accurate and complex. This increasing complexity induces a significant increase in computation time which prevents the possibility of using this model in certain applications and studies. Accordingly, the aim of this work is to significantly reduce the computation time of high-density surface electromyogram (HD-sEMG) generation. This will be done through a new model of motor unit (MU)-specific electrical source based on the fibers composing the MU. In order to assess the efficiency of this approach, we computed the normalized root mean square error (NRMSE) between several simulations on single generated MU action potential (MUAP) using the usual fiber electrical sources and the MU-specific electrical source. This NRMSE was computed for five different simulation sets wherein hundreds of MUAPs are generated and summed into HD-sEMG signals. The obtained results display less than 2% error on the generated signals compared to the same signals generated with fiber electrical sources. Moreover, the computation time of the HD-sEMG signal generation model is reduced to about 90% compared to the fiber electrical source model. Using this model with MU electrical sources, we can simulate HD-sEMG signals of a physiological muscle (hundreds of MU) in less than an hour on a classical workstation. Graphical Abstract Overview of the simulation of HD-sEMG signals using the fiber scale and the MU scale. Upscaling the electrical source to the MU scale reduces the computation time by 90% inducing only small deviation of the same simulated HD-sEMG signals.

Computer Simulation of Spatial Arrangement and Connectivity of Particles in Three-Dimensional Microstructure: Application to Model Electrical Conductivity of Polymer Matrix Composite

NASA Technical Reports Server (NTRS)

Louis, P.; Gokhale, A. M.

1996-01-01

Computer simulation is a powerful tool for analyzing the geometry of three-dimensional microstructure. A computer simulation model is developed to represent the three-dimensional microstructure of a two-phase particulate composite where particles may be in contact with one another but do not overlap significantly. The model is used to quantify the "connectedness" of the particulate phase of a polymer matrix composite containing hollow carbon particles in a dielectric polymer resin matrix. The simulations are utilized to estimate the morphological percolation volume fraction for electrical conduction, and the effective volume fraction of the particles that actually take part in the electrical conduction. The calculated values of the effective volume fraction are used as an input for a self-consistent physical model for electrical conductivity. The predicted values of electrical conductivity are in very good agreement with the corresponding experimental data on a series of specimens having different particulate volume fraction.

Auditory sensitivity of larval zebrafish (Danio rerio) measured using a behavioral prepulse inhibition assay

PubMed Central

Bhandiwad, Ashwin A.; Zeddies, David G.; Raible, David W.; Rubel, Edwin W.; Sisneros, Joseph A.

2013-01-01

SUMMARY Zebrafish (Danio rerio) have become a valuable model for investigating the molecular genetics and development of the inner ear in vertebrates. In this study, we employed a prepulse inhibition (PPI) paradigm to assess hearing in larval wild-type (AB) zebrafish during early development at 5–6 days post-fertilization (d.p.f.). We measured the PPI of the acoustic startle response in zebrafish using a 1-dimensional shaker that simulated the particle motion component of sound along the fish's dorsoventral axis. The thresholds to startle-inducing stimuli were determined in 5–6 d.p.f. zebrafish, and their hearing sensitivity was then characterized using the thresholds of prepulse tone stimuli (90–1200 Hz) that inhibited the acoustic startle response to a reliable startle stimulus (820 Hz at 20 dB re. 1 m s−2). Hearing thresholds were defined as the minimum prepulse tone level required to significantly reduce the startle response probability compared with the baseline (no-prepulse) condition. Larval zebrafish showed greatest auditory sensitivity from 90 to 310 Hz with corresponding mean thresholds of −19 to −10 dB re. 1 m s−2, respectively. Hearing thresholds of prepulse tones were considerably lower than previously predicted by startle response assays. The PPI assay was also used to investigate the relative contribution of the lateral line to the detection of acoustic stimuli. After aminoglycoside-induced neuromast hair-cell ablation, we found no difference in PPI thresholds between treated and control fish. We propose that this PPI assay can be used to screen for novel zebrafish hearing mutants and to investigate the ontogeny of hearing in zebrafish and other fishes. PMID:23966590

Road map to Title I of the Public Utility Regulatory Policies Act of 1978

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

Partridge, W.

1979-01-18

Within the next two years all electric utilities retailing over 500 million kilowatts per year will be forced into rate-making proceedings or public hearings to meet the requirements of Title I of the Public Utility Regulatory Policies Act of 1978. In these proceedings they will be required to consider the application of Federal requirements for lifeline rates, class rates based on cost of service, declining block rates, time-of-day rates, seasonal rates, interruptible rates, load management techniques, prohibitions on master metering, restrictions on use of automatic adjustment clauses, provision of consumer information, termination procedures, and restrictions on advertising. The act hasmore » immediate, significant implications for electric utility management.« less

Tonic effects of the dopaminergic ventral midbrain on the auditory cortex of awake macaque monkeys.

PubMed

Huang, Ying; Mylius, Judith; Scheich, Henning; Brosch, Michael

2016-03-01

This study shows that ongoing electrical stimulation of the dopaminergic ventral midbrain can modify neuronal activity in the auditory cortex of awake primates for several seconds. This was reflected in a decrease of the spontaneous firing and in a bidirectional modification of the power of auditory evoked potentials. We consider that both effects are due to an increase in the dopamine tone in auditory cortex induced by the electrical stimulation. Thus, the dopaminergic ventral midbrain may contribute to the tonic activity in auditory cortex that has been proposed to be involved in associating events of auditory tasks (Brosch et al. Hear Res 271:66-73, 2011) and may modulate the signal-to-noise ratio of the responses to auditory stimuli.

Conductive network formation of carbon nanotubes in elastic polymer microfibers and its effect on the electrical conductance: Experiment and simulation

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

Cho, Hyun Woo; Kim, Jeongmin; Sung, Bong June, E-mail: jjpark@chonnam.ac.kr, E-mail: bjsung@sogang.ac.kr

We investigate how the electrical conductance of microfibers (made of polymers and conductive nanofillers) decreases upon uniaxial deformation by performing both experiments and simulations. Even though various elastic conductors have been developed due to promising applications for deformable electronic devices, the mechanism at a molecular level for electrical conductance change has remained elusive. Previous studies proposed that the decrease in electrical conductance would result from changes in either distances or contact numbers between conductive fillers. In this work, we prepare microfibers of single walled carbon nanotubes (SWCNTs)/polyvinyl alcohol composites and investigate the electrical conductance and the orientation of SWCNTs uponmore » uniaxial deformation. We also perform extensive Monte Carlo simulations, which reproduce experimental results for the relative decrease in conductance and the SWCNTs orientation. We investigate the electrical networks of SWCNTs in microfibers and find that the decrease in the electrical conductance upon uniaxial deformation should be attributed to a subtle change in the topological structure of the electrical network.« less

Electric Vehicles in Colorado: Anticipating Consumer Demand for Direct Current Fast Charging

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

Wood, Eric W.; Rames, Clement L.

To support the State of Colorado in planning for growth in direct current fast charging (DCFC) for electric vehicles, the National Renewable Energy Laboratory (NREL) has partnered with the Regional Air Quality Council (RAQC) and the Colorado Department of Transportation (CDOT) to analyze a number of DCFC investment scenarios. NREL analyzed existing electric vehicle registration data from IHS Markit (IHS) to highlight early trends in the electric vehicle market, which were compared with sales forecasts predicting large growth in the Colorado electric vehicle market. Electric vehicle forecasts were then used to develop future DCFC scenarios to be evaluated in amore » simulation environment to estimate consumer benefits of the hypothetical DCFC networks in terms of increased driving range and electric vehicle miles traveled (eVMT). Simulated utilization of the hypothetical DCFC networks was analyzed for geographic trends, particularly for correlations with vehicle electric range. Finally, a subset of simulations is presented for consumers with potentially inconsistent access to charging at their home location and presumably greater reliance on public DCFC infrastructure.« less

Simulation of electrostatic ion instabilities in the presence of parallel currents and transverse electric fields

NASA Technical Reports Server (NTRS)

Nishikawa, K.-I.; Ganguli, G.; Lee, Y. C.; Palmadesso, P. J.

1989-01-01

A spatially two-dimensional electrostatic PIC simulation code was used to study the stability of a plasma equilibrium characterized by a localized transverse dc electric field and a field-aligned drift for L is much less than Lx, where Lx is the simulation length in the x direction and L is the scale length associated with the dc electric field. It is found that the dc electric field and the field-aligned current can together play a synergistic role to enable the excitation of electrostatic waves even when the threshold values of the field aligned drift and the E x B drift are individually subcritical. The simulation results show that the growing ion waves are associated with small vortices in the linear stage, which evolve to the nonlinear stage dominated by larger vortices with lower frequencies.

An econometric simulation model of income and electricity demand in Alaska's Railbelt, 1982-2022

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

Maddigan, R.J.; Hill, L.J.; Hamblin, D.M.

1987-01-01

This report describes the specification of-and forecasts derived from-the Alaska Railbelt Electricity Load, Macroeconomic (ARELM) model. ARELM was developed as an independent, modeling tool for the evaluation of the need for power from the Susitna Hydroelectric Project which has been proposed by the Alaska Power Authority. ARELM is an econometric simulation model consisting of 61 equations - 46 behavioral equations and 15 identities. The system includes two components: (1) ARELM-MACRO which is a system of equations that simulates the performance of both the total Alaskan and Railbelt macroeconomies and (2) ARELM-LOAD which projects electricity-related activity in the Alaskan Railbelt region.more » The modeling system is block recursive in the sense that forecasts of population, personal income, and employment in the Railbelt derived from ARELM-MACRO are used as explanatory variables in ARELM-LOAD to simulate electricity demand, the real average price of electricity, and the number of customers in the Railbelt. Three scenarios based on assumptions about the future price of crude oil are simulated and documented in the report. The simulations, which do not include the cost-of-power impacts of Susitna-based generation, show that the growth rate in Railbelt electricity load is between 2.5 and 2.7% over the 1982 to 2022 forecast period. The forecasting results are consistent with other projections of load growth in the region using different modeling approaches.« less

Numerical simulation of electromagnetic fields and impedance of CERN LINAC4 H(-) source taking into account the effect of the plasma.

PubMed

Grudiev, A; Lettry, J; Mattei, S; Paoluzzi, M; Scrivens, R

2014-02-01

Numerical simulation of the CERN LINAC4 H(-) source 2 MHz RF system has been performed taking into account a realistic geometry from 3D Computer Aided Design model using commercial FEM high frequency simulation code. The effect of the plasma has been added to the model by the approximation of a homogenous electrically conducting medium. Electric and magnetic fields, RF power losses, and impedance of the circuit have been calculated for different values of the plasma conductivity. Three different regimes have been found depending on the plasma conductivity: (1) Zero or low plasma conductivity results in RF electric field induced by the RF antenna being mainly capacitive and has axial direction; (2) Intermediate conductivity results in the expulsion of capacitive electric field from plasma and the RF power coupling, which is increasing linearly with the plasma conductivity, is mainly dominated by the inductive azimuthal electric field; (3) High conductivity results in the shielding of both the electric and magnetic fields from plasma due to the skin effect, which reduces RF power coupling to plasma. From these simulations and measurements of the RF power coupling on the CERN source, a value of the plasma conductivity has been derived. It agrees well with an analytical estimate calculated from the measured plasma parameters. In addition, the simulated and measured impedances with and without plasma show very good agreement as well demonstrating validity of the plasma model used in the RF simulations.

A generic model of real-world non-ideal behaviour of FES-induced muscle contractions: simulation tool

NASA Astrophysics Data System (ADS)

Lynch, Cheryl L.; Graham, Geoff M.; Popovic, Milos R.

2011-08-01

Functional electrical stimulation (FES) applications are frequently evaluated in simulation prior to testing in human subjects. Such simulations are usually based on the typical muscle responses to electrical stimulation, which may result in an overly optimistic assessment of likely real-world performance. We propose a novel method for simulating FES applications that includes non-ideal muscle behaviour during electrical stimulation resulting from muscle fatigue, spasms and tremors. A 'non-idealities' block that can be incorporated into existing FES simulations and provides a realistic estimate of real-world performance is described. An implementation example is included, showing how the non-idealities block can be incorporated into a simulation of electrically stimulated knee extension against gravity for both a proportional-integral-derivative controller and a sliding mode controller. The results presented in this paper illustrate that the real-world performance of a FES system may be vastly different from the performance obtained in simulation using nominal muscle models. We believe that our non-idealities block should be included in future simulations that involve muscle response to FES, as this tool will provide neural engineers with a realistic simulation of the real-world performance of FES systems. This simulation strategy will help engineers and organizations save time and money by preventing premature human testing. The non-idealities block will become available free of charge at www.toronto-fes.ca in late 2011.

Test-retest reliability of probe-microphone verification in children fitted with open and closed hearing aid tips.

PubMed

Kim, Hannah; Ricketts, Todd A

2013-01-01

To investigate the test-retest reliability of real-ear aided response (REAR) measures in open and closed hearing aid fittings in children using appropriate probe-microphone calibration techniques (stored equalization for open fittings and concurrent equalization for closed fittings). Probe-microphone measurements were completed for two mini-behind-the-ear (BTE) hearing aids which were coupled to the ear using open and closed eartips via thin (0.9 mm) tubing. Before probe-microphone testing, the gain of each of the test hearing aids was programmed using an artificial ear simulator (IEC 711) and a Knowles Electronic Manikin for Acoustic Research to match the National Acoustic Laboratories-Non-Linear, version 1 targets for one of two separate hearing loss configurations using an Audioscan Verifit. No further adjustments were made, and the same amplifier gain was used within each hearing aid across both eartip configurations and all participants. Probe-microphone testing included real-ear occluded response (REOR) and REAR measures using the Verifit's standard speech signal (the carrot passage) presented at 65 dB sound pressure level (SPL). Two repeated probe-microphone measures were made for each participant with the probe-tube and hearing aid removed and repositioned between each trial in order to assess intrasubject measurement variability. These procedures were repeated using both open and closed domes. Thirty-two children, ages ranging from 4 to 14 yr. The test-retest standard deviations for open and closed measures did not exceed 4 dB at any frequency. There was also no significant difference between the open (stored equalization) and closed (concurrent equalization) methods. Reliability was particularly similar in the high frequencies and was also quite similar to that reported in previous research. There was no correlation between reliability and age, suggesting high reliability across all ages evaluated. The findings from this study suggest that reliable probe-microphone measurements are obtainable on children 4 yr and older for both traditional unvented and open-canal hearing aid fittings. These data suggest that clinicians should not avoid fitting open technology to children as young as 4 y because of concerns regarding the reliability of verification techniques. American Academy of Audiology.

Project ITCH: Interactive Digital Simulation in Electrical Engineering Education.

ERIC Educational Resources Information Center

Bailey, F. N.; Kain, R. Y.

A two-stage project is investigating the educational potential of a low-cost time-sharing system used as a simulation tool in Electrical Engineering (EE) education. Phase I involves a pilot study and Phase II a full integration. The system employs interactive computer simulation to teach engineering concepts which are not well handled by…

Transient Analysis Generator /TAG/ simulates behavior of large class of electrical networks

NASA Technical Reports Server (NTRS)

Thomas, W. J.

1967-01-01

Transient Analysis Generator program simulates both transient and dc steady-state behavior of a large class of electrical networks. It generates a special analysis program for each circuit described in an easily understood and manipulated programming language. A generator or preprocessor and a simulation system make up the TAG system.

Subcortical amplitude modulation encoding deficits suggest evidence of cochlear synaptopathy in normal-hearing 18-19 year olds with higher lifetime noise exposure.

PubMed

Paul, Brandon T; Waheed, Sajal; Bruce, Ian C; Roberts, Larry E

2017-11-01

Noise exposure and aging can damage cochlear synapses required for suprathreshold listening, even when cochlear structures needed for hearing at threshold remain unaffected. To control for effects of aging, behavioral amplitude modulation (AM) detection and subcortical envelope following responses (EFRs) to AM tones in 25 age-restricted (18-19 years) participants with normal thresholds, but different self-reported noise exposure histories were studied. Participants with more noise exposure had smaller EFRs and tended to have poorer AM detection than less-exposed individuals. Simulations of the EFR using a well-established cochlear model were consistent with more synaptopathy in participants reporting greater noise exposure.

Molecular dynamics simulations of dislocations in TlBr crystals under an electrical field

DOE PAGES

Zhou, X. W.; Foster, M. E.; Yang, P.; ...

2016-07-13

TlBr crystals have superior radiation detection properties; however, their properties degrade in the range of hours to weeks when an operating electrical field is applied. To account for this rapid degradation using the widely-accepted vacancy migration mechanism, the vacancy concentration must be orders of magnitude higher than any conventional estimates. The present work has incorporated a new analytical variable charge model in molecular dynamics (MD) simulations to examine the structural changes of materials under electrical fields. Our simulations indicate that dislocations in TlBr move under electrical fields. As a result, this discovery can lead to new understanding of TlBr agingmore » mechanisms under external fields.« less

Electronic filters, signal conversion apparatus, hearing aids and methods

NASA Technical Reports Server (NTRS)

Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

1992-01-01

An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits as GOVERNMENT SUPPORT This invention was made with U.S. Government support under Veterans Administration Contract VA KV 674P857 and National Aeronautics and Space Administration (NASA) Research Grant No. NAG10-0040. The U.S. Government has certain rights in this invention.

Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator.

PubMed

Luo, Chuan; Omelchenko, Irina; Manson, Robert; Robbins, Carol; Oesterle, Elizabeth C; Cao, Guo Zhong; Shen, I Y; Hume, Clifford R

2015-12-01

Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800 µm by 800 µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24 kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays. © The Author(s) 2015.

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

PubMed

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

2016-01-01

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

Noise reduction technologies implemented in head-worn preprocessors for improving cochlear implant performance in reverberant noise fields.

PubMed

Chung, King; Nelson, Lance; Teske, Melissa

2012-09-01

The purpose of this study was to investigate whether a multichannel adaptive directional microphone and a modulation-based noise reduction algorithm could enhance cochlear implant performance in reverberant noise fields. A hearing aid was modified to output electrical signals (ePreprocessor) and a cochlear implant speech processor was modified to receive electrical signals (eProcessor). The ePreprocessor was programmed to flat frequency response and linear amplification. Cochlear implant listeners wore the ePreprocessor-eProcessor system in three reverberant noise fields: 1) one noise source with variable locations; 2) three noise sources with variable locations; and 3) eight evenly spaced noise sources from 0° to 360°. Listeners' speech recognition scores were tested when the ePreprocessor was programmed to omnidirectional microphone (OMNI), omnidirectional microphone plus noise reduction algorithm (OMNI + NR), and adaptive directional microphone plus noise reduction algorithm (ADM + NR). They were also tested with their own cochlear implant speech processor (CI_OMNI) in the three noise fields. Additionally, listeners rated overall sound quality preferences on recordings made in the noise fields. Results indicated that ADM+NR produced the highest speech recognition scores and the most preferable rating in all noise fields. Factors requiring attention in the hearing aid-cochlear implant integration process are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Motion Simulator

NASA Technical Reports Server (NTRS)

1993-01-01

MOOG, Inc. supplies hydraulic actuators for the Space Shuttle. When MOOG learned NASA was interested in electric actuators for possible future use, the company designed them with assistance from Marshall Space Flight Center. They also decided to pursue the system's commercial potential. This led to partnership with InterActive Simulation, Inc. for production of cabin flight simulators for museums, expositions, etc. The resulting products, the Magic Motion Simulator 30 Series, are the first electric powered simulators. Movements are computer-guided, including free fall to heighten the sense of moving through space. A projection system provides visual effects, and the 11 speakers of a digital laser based sound system add to the realism. The electric actuators are easier to install, have lower operating costs, noise, heat and staff requirements. The U.S. Space & Rocket Center and several other organizations have purchased the simulators.

Experimental study and simulation of space charge stimulated discharge

NASA Astrophysics Data System (ADS)

Noskov, M. D.; Malinovski, A. S.; Cooke, C. M.; Wright, K. A.; Schwab, A. J.

2002-11-01

The electrical discharge of volume distributed space charge in poly(methylmethacrylate) (PMMA) has been investigated both experimentally and by computer simulation. The experimental space charge was implanted in dielectric samples by exposure to a monoenergetic electron beam of 3 MeV. Electrical breakdown through the implanted space charge region within the sample was initiated by a local electric field enhancement applied to the sample surface. A stochastic-deterministic dynamic model for electrical discharge was developed and used in a computer simulation of these breakdowns. The model employs stochastic rules to describe the physical growth of the discharge channels, and deterministic laws to describe the electric field, the charge, and energy dynamics within the discharge channels and the dielectric. Simulated spatial-temporal and current characteristics of the expanding discharge structure during physical growth are quantitatively compared with the experimental data to confirm the discharge model. It was found that a single fixed set of physically based dielectric parameter values was adequate to simulate the complete family of experimental space charge discharges in PMMA. It is proposed that such a set of parameters also provides a useful means to quantify the breakdown properties of other dielectrics.

Neurotrophins and electrical stimulation for protection and repair of spiral ganglion neurons following sensorineural hearing loss

PubMed Central

Shepherd, Robert K.; Coco, Anne; Epp, Stephanie B.

2008-01-01

Exogenous neurotrophins (NTs) have been shown to rescue spiral ganglion neurons (SGNs) from degeneration following a sensorineural hearing loss (SNHL). Furthermore, chronic electrical stimulation (ES) has been shown to retard SGN degeneration in some studies but not others. Since there is evidence of even greater SGN rescue when NT administration is combined with ES, we examined whether chronic ES can maintain SGN survival long after cessation of NT delivery. Young adult guinea pigs were profoundly deafened using ototoxic drugs; five days later they were unilaterally implanted with an electrode array and drug delivery system. Brain derived neurotrophic factor (BDNF) was continuously delivered to the scala tympani over a four week period while the animal simultaneously received ES via bipolar electrodes in the basal turn (i.e. turn 1) scala tympani. One cohort (n=5) received ES for six weeks (i.e. including a two week period after the cessation of BDNF delivery; ES6); a second cohort (n=5) received ES for 10 weeks (i.e. a six week period following cessation of BDNF delivery; ES10). The cochleae were harvested for histology and SGN density determined for each cochlear turn for comparison with normal hearing controls (n=4). The withdrawal of BDNF resulted in a rapid loss of SGNs in turns 2–4 of the deafened/BDNF-treated cochleae; this was significant as early as two weeks following removal of the NT when compared with normal controls (p<0.05). Importantly, there was not a significant reduction in SGNs in turn 1 (i.e. adjacent to the electrode array) two and six weeks after NT removal, as compared with normal controls. This result suggests that chronic ES can prevent the rapid loss of SGNs that occurs after the withdrawal of exogenous NTs. Implications for the clinical delivery of NTs are discussed. PMID:18243608

Electron Acceleration in the Magnetotail during Substorms in Semi-Global PIC Simulations

NASA Astrophysics Data System (ADS)

Richard, R. L.; Schriver, D.; Ashour-Abdalla, M.; El-Alaoui, M.; Lapenta, G.; Walker, R. J.

2015-12-01

To understand the acceleration of electrons during a substorm reconnection event we have applied a semi-global particle in cell (PIC) simulation box embedded within a global magnetohydrodynamic (MHD) simulation of Earth's magnetosphere for an event on February 15, 2008. The MHD results were used to populate the PIC simulation and to set the boundary conditions. In the magnetotail we found that a series of dipolarizations formed due to unsteady reconnection. We also found that the most energetic electrons were in the separatrices far from the x-point. We attributed the acceleration to a streaming instability in the separatrices. To further understand electron acceleration we have applied the large scale kinetic (LSK) technique in which tens- to hundreds- of thousands of electrons are followed within the electric and magnetic fields from the PIC simulations., Electrons are already included in the PIC simulation, but the LSK simulations will allow selected individual particles to be followed and analyzed. Initially we performed electron LSK calculations in a two dimensional version of the PIC simulation in which electrons were allowed to move in the ignorable cross tail direction. These LSK calculations showed that electrons gained energy primarily for two reasons: (1) acceleration by the average dawn to dusk electric field and (2) acceleration by intense but localized electric field structures. The overall electron transport was more dawnward than duskward due to the average electric field. At the same time electrons typically moved away from the reconnection region in both the earthward and tailward directions. Superimposed on this large-scale transport was motion in both the dusk and dawn directions across the tail because of the electric field structures, which were particularly intense in the separatrices. LSK calculations are now being carried out by using the full three-dimensional magnetic and electric fields from the PIC simulation and these results will be compared with the two-dimensional results for the same substorm event.

Audiovisual Cues and Perceptual Learning of Spectrally Distorted Speech

ERIC Educational Resources Information Center

Pilling, Michael; Thomas, Sharon

2011-01-01

Two experiments investigate the effectiveness of audiovisual (AV) speech cues (cues derived from both seeing and hearing a talker speak) in facilitating perceptual learning of spectrally distorted speech. Speech was distorted through an eight channel noise-vocoder which shifted the spectral envelope of the speech signal to simulate the properties…

Simulation of Electric Propulsion Thrusters (Preprint)

DTIC Science & Technology

2011-02-07

activity concerns the plumes produced by electric thrusters. Detailed information on the plumes is required for safe integration of the thruster...ground-based laboratory facilities. Device modelling also plays an important role in plume simulations by providing accurate boundary conditions at...methods used to model the flow of gas and plasma through electric propulsion devices. Discussion of the numerical analysis of other aspects of

Reduction technique of drop voltage and power losses to improve power quality using ETAP Power Station simulation model

NASA Astrophysics Data System (ADS)

Satrio, Reza Indra; Subiyanto

2018-03-01

The effect of electric loads growth emerged direct impact in power systems distribution. Drop voltage and power losses one of the important things in power systems distribution. This paper presents modelling approach used to restructrure electrical network configuration, reduce drop voltage, reduce power losses and add new distribution transformer to enhance reliability of power systems distribution. Restructrure electrical network was aimed to analyse and investigate electric loads of a distribution transformer. Measurement of real voltage and real current were finished two times for each consumer, that were morning period and night period or when peak load. Design and simulation were conduct by using ETAP Power Station Software. Based on result of simulation and real measurement precentage of drop voltage and total power losses were mismatch with SPLN (Standard PLN) 72:1987. After added a new distribution transformer and restructrured electricity network configuration, the result of simulation could reduce drop voltage from 1.3 % - 31.3 % to 8.1 % - 9.6 % and power losses from 646.7 watt to 233.29 watt. Result showed, restructrure electricity network configuration and added new distribution transformer can be applied as an effective method to reduce drop voltage and reduce power losses.

Generation of induced neurons by direct reprogramming in the mammalian cochlea.

PubMed

Nishimura, K; Weichert, R M; Liu, W; Davis, R L; Dabdoub, A

2014-09-05

Primary auditory neurons (ANs) in the mammalian cochlea play a critical role in hearing as they transmit auditory information in the form of electrical signals from mechanosensory cochlear hair cells in the inner ear to the brainstem. Their progressive degeneration is associated with disease conditions, excessive noise exposure and aging. Replacement of ANs, which lack the ability to regenerate spontaneously, would have a significant impact on research and advancement in cochlear implants in addition to the amelioration of hearing impairment. The aim of this study was to induce a neuronal phenotype in endogenous non-neural cells in the cochlea, which is the essential organ of hearing. Overexpression of a neurogenic basic helix-loop-helix transcription factor, Ascl1, in the cochlear non-sensory epithelial cells induced neurons at high efficiency at embryonic, postnatal and juvenile stages. Moreover, induced neurons showed typical properties of neuron morphology, gene expression and electrophysiology. Our data indicate that Ascl1 alone or Ascl1 and NeuroD1 is sufficient to reprogram cochlear non-sensory epithelial cells into functional neurons. Generation of neurons from non-neural cells in the cochlea is an important step for the regeneration of ANs in the mature mammalian cochlea. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Diverse Roles of Axonemal Dyneins in Drosophila Auditory Neuron Function and Mechanical Amplification in Hearing.

PubMed

Karak, Somdatta; Jacobs, Julie S; Kittelmann, Maike; Spalthoff, Christian; Katana, Radoslaw; Sivan-Loukianova, Elena; Schon, Michael A; Kernan, Maurice J; Eberl, Daniel F; Göpfert, Martin C

2015-11-26

Much like vertebrate hair cells, the chordotonal sensory neurons that mediate hearing in Drosophila are motile and amplify the mechanical input of the ear. Because the neurons bear mechanosensory primary cilia whose microtubule axonemes display dynein arms, we hypothesized that their motility is powered by dyneins. Here, we describe two axonemal dynein proteins that are required for Drosophila auditory neuron function, localize to their primary cilia, and differently contribute to mechanical amplification in hearing. Promoter fusions revealed that the two axonemal dynein genes Dmdnah3 (=CG17150) and Dmdnai2 (=CG6053) are expressed in chordotonal neurons, including the auditory ones in the fly's ear. Null alleles of both dyneins equally abolished electrical auditory neuron responses, yet whereas mutations in Dmdnah3 facilitated mechanical amplification, amplification was abolished by mutations in Dmdnai2. Epistasis analysis revealed that Dmdnah3 acts downstream of Nan-Iav channels in controlling the amplificatory gain. Dmdnai2, in addition to being required for amplification, was essential for outer dynein arms in auditory neuron cilia. This establishes diverse roles of axonemal dyneins in Drosophila auditory neuron function and links auditory neuron motility to primary cilia and axonemal dyneins. Mutant defects in sperm competition suggest that both dyneins also function in sperm motility.

Interservice/Industry Training Systems Conference (13th) Held in Orlando, Florida on 2-5 December 1991

DTIC Science & Technology

1991-12-01

within the be able to design and implement tactile feedback, cube. These simulations range from pc-oased binaural hearing, and autosterioscopic...of the 6-per-revolution beat simulate local wind velocities near the hub. experienced by the tandem 3-blade rotor hubs of the CH46, thus minimizing the...totally -- taking inventory and main- ignored- in another. For example, the taining the security of the videotape entitled " Beating the Odds -- of the

Effects of Age and Working Memory Capacity on Speech Recognition Performance in Noise Among Listeners With Normal Hearing.

PubMed

Gordon-Salant, Sandra; Cole, Stacey Samuels

2016-01-01

This study aimed to determine if younger and older listeners with normal hearing who differ on working memory span perform differently on speech recognition tests in noise. Older adults typically exhibit poorer speech recognition scores in noise than younger adults, which is attributed primarily to poorer hearing sensitivity and more limited working memory capacity in older than younger adults. Previous studies typically tested older listeners with poorer hearing sensitivity and shorter working memory spans than younger listeners, making it difficult to discern the importance of working memory capacity on speech recognition. This investigation controlled for hearing sensitivity and compared speech recognition performance in noise by younger and older listeners who were subdivided into high and low working memory groups. Performance patterns were compared for different speech materials to assess whether or not the effect of working memory capacity varies with the demands of the specific speech test. The authors hypothesized that (1) normal-hearing listeners with low working memory span would exhibit poorer speech recognition performance in noise than those with high working memory span; (2) older listeners with normal hearing would show poorer speech recognition scores than younger listeners with normal hearing, when the two age groups were matched for working memory span; and (3) an interaction between age and working memory would be observed for speech materials that provide contextual cues. Twenty-eight older (61 to 75 years) and 25 younger (18 to 25 years) normal-hearing listeners were assigned to groups based on age and working memory status. Northwestern University Auditory Test No. 6 words and Institute of Electrical and Electronics Engineers sentences were presented in noise using an adaptive procedure to measure the signal-to-noise ratio corresponding to 50% correct performance. Cognitive ability was evaluated with two tests of working memory (Listening Span Test and Reading Span Test) and two tests of processing speed (Paced Auditory Serial Addition Test and The Letter Digit Substitution Test). Significant effects of age and working memory capacity were observed on the speech recognition measures in noise, but these effects were mediated somewhat by the speech signal. Specifically, main effects of age and working memory were revealed for both words and sentences, but the interaction between the two was significant for sentences only. For these materials, effects of age were observed for listeners in the low working memory groups only. Although all cognitive measures were significantly correlated with speech recognition in noise, working memory span was the most important variable accounting for speech recognition performance. The results indicate that older adults with high working memory capacity are able to capitalize on contextual cues and perform as well as young listeners with high working memory capacity for sentence recognition. The data also suggest that listeners with normal hearing and low working memory capacity are less able to adapt to distortion of speech signals caused by background noise, which requires the allocation of more processing resources to earlier processing stages. These results indicate that both younger and older adults with low working memory capacity and normal hearing are at a disadvantage for recognizing speech in noise.

Validity of the Hum Test, a Simple and Reliable Alternative to the Weber Test.

PubMed

Ahmed, Omar H; Gallant, Sara C; Ruiz, Ryan; Wang, Binhuan; Shapiro, William H; Voigt, Erich P

2018-06-01

To compare the diagnostic performance of the Hum Test against the Weber Test using pure tone audiometry (PTA) as the "gold standard" comparator. 29 participants with normal hearing of ages 18 to 35 without any history of hearing abnormalities or otologic conditions were enrolled. Subjects underwent three tests (Hum Test, Weber Test, and PTA) across two conditions: with an ear plug in one ear (side randomized) and without ear plugs. When examining the ability of the Hum Test to detect simulated conductive hearing loss (CHL), the test had a sensitivity of 89.7% and specificity of 100% with high pitched humming and 93.1% and 100%, respectively, with low pitched humming. The Weber Test had a sensitivity and specificity of 96.6% and 100%, respectively. McNemar's test demonstrated agreement between the Hum Test, performed with either high pitched ( P = .32) or low pitched ( P = .56) humming, and the Weber Test. Receiver operating characteristic (ROC) curves for the Hum Test (both high and low pitched) and Weber test were compared and demonstrated no statistically significant difference. The Hum Test is comparable to the Weber Test with regards to its sensitivity, specificity, and diagnostic accuracy in assessing new onset unilateral CHL in previously normal hearing subjects.

Fast Computation of High Energy Elastic Collision Scattering Angle for Electric Propulsion Plume Simulation (Conference Paper with Briefing Charts)

DTIC Science & Technology

2016-07-10

Elastic Collision Scattering Angle for Electric Propulsion Plume Simulation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...atom needs to be sampled; however, it is confirmed that initial target atom velocity does not play significant role in typical electric propulsion ...by ANSI Std. 239.18 Fast Computation of High Energy Elastic Collision Scattering Angle for Electric Propulsion Plume Simulation∗ Samuel J. Araki1

Simulation study on electric field intensity above train roof

NASA Astrophysics Data System (ADS)

Fan, Yizhe; Li, Huawei; Yang, Shasha

2018-04-01

In order to understand the distribution of electric field in the space above the train roof accurately and select the installation position of the detection device reasonably, in this paper, the 3D model of pantograph-catenary is established by using SolidWorks software, and the spatial electric field distribution of pantograph-catenary model is simulated based on Comsol software. According to the electric field intensity analysis within the 0.4m space above train roof, we give a reasonable installation of the detection device.

Intracochlear electrical stimulation suppresses apoptotic signaling in rat spiral ganglion neurons after deafening in vivo.

PubMed

Kopelovich, Jonathan C; Cagaanan, Alain P; Miller, Charles A; Abbas, Paul J; Green, Steven H

2013-11-01

To establish the intracellular consequences of electrical stimulation to spiral ganglion neurons after deafferentation. Here we use a rat model to determine the effect of both low and high pulse rate acute electrical stimulation on activation of the proapoptotic transcription factor Jun in deafferented spiral ganglion neurons in vivo. Experimental animal study. Hearing research laboratories of the University of Iowa Departments of Biology and Otolaryngology. A single electrode was implanted through the round window of kanamycin-deafened rats at either postnatal day 32 (P32, n = 24) or P60 (n = 22) for 4 hours of stimulation (monopolar, biphasic pulses, amplitude twice electrically evoked auditory brainstem response [eABR] threshold) at either 100 or 5000 Hz. Jun phosphorylation was assayed by immunofluorescence to quantitatively assess the effect of electrical stimulation on proapoptotic signaling. Jun phosphorylation was reliably suppressed by 100 Hz stimuli in deafened cochleae of P32 but not P60 rats. This effect was not significant in the basal cochlear turns. Stimulation frequency may be consequential: 100 Hz was significantly more effective than was 5 kHz stimulation in suppressing phospho-Jun. Suppression of Jun phosphorylation occurs in deafferented spiral ganglion neurons after only 4 hours of electrical stimulation. This finding is consistent with the hypothesis that electrical stimulation can decrease spiral ganglion neuron death after deafferentation.

Investigations in thunderstorm energetics using satellite instrumentation and Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Brunner, K. N.; Bitzer, P. M.

2017-12-01

The electrical energy dissipated by lightning is a fundamental question in lightning physics and may be used in severe weather applications. However, the electrical energy, flash area/extent and spectral energy density (radiance) are all influenced by the geometry of the lightning channel. We present details of a Monte Carlo based model simulating the optical emission from lightning and compare with observations. Using time-of-arrival techniques and the electric field change measurements from the Huntsville Alabama Marx Meter Array (HAMMA), the 4D lightning channel is reconstructed. The located sources and lightning channel emit optical emission, calibrated by the ground based electric field, that scatters until absorbed or a cloud boundary is reached within the model. At cloud top, the simulation is gridded as LIS pixels (events) and contiguous events (groups). The radiance is related via the LIS calibration and the estimated lightning electrical energy is calculated at the LIS/GLM time resolution. Previous Monte Carlo simulations have relied on a simplified lightning channel and scattering medium. This work considers the cloud a stratified medium of graupel/ice and inhomogeneous at flash scale. The impact of cloud inhomogeneity on the scattered optical emission at cloud top and at the time resolution of LIS and GLM are also considered. The simulation results and energy metrics provide an estimation of the electrical energy using GLM and LIS on the International Space Station (ISS-LIS).

Sentence Recognition Prediction for Hearing-impaired Listeners in Stationary and Fluctuation Noise With FADE

PubMed Central

Schädler, Marc René; Warzybok, Anna; Meyer, Bernd T.; Brand, Thomas

2016-01-01

To characterize the individual patient’s hearing impairment as obtained with the matrix sentence recognition test, a simulation Framework for Auditory Discrimination Experiments (FADE) is extended here using the Attenuation and Distortion (A+D) approach by Plomp as a blueprint for setting the individual processing parameters. FADE has been shown to predict the outcome of both speech recognition tests and psychoacoustic experiments based on simulations using an automatic speech recognition system requiring only few assumptions. It builds on the closed-set matrix sentence recognition test which is advantageous for testing individual speech recognition in a way comparable across languages. Individual predictions of speech recognition thresholds in stationary and in fluctuating noise were derived using the audiogram and an estimate of the internal level uncertainty for modeling the individual Plomp curves fitted to the data with the Attenuation (A-) and Distortion (D-) parameters of the Plomp approach. The “typical” audiogram shapes from Bisgaard et al with or without a “typical” level uncertainty and the individual data were used for individual predictions. As a result, the individualization of the level uncertainty was found to be more important than the exact shape of the individual audiogram to accurately model the outcome of the German Matrix test in stationary or fluctuating noise for listeners with hearing impairment. The prediction accuracy of the individualized approach also outperforms the (modified) Speech Intelligibility Index approach which is based on the individual threshold data only. PMID:27604782

Carrier trajectory tracking equations for Simple-band Monte Carlo simulation of avalanche multiplication processes

NASA Astrophysics Data System (ADS)

Ong, J. S. L.; Charin, C.; Leong, J. H.

2017-12-01

Avalanche photodiodes (APDs) with steep electric field gradients generally have low excess noise that arises from carrier multiplication within the internal gain of the devices, and the Monte Carlo (MC) method is among popular device simulation tools for such devices. However, there are few articles relating to carrier trajectory modeling in MC models for such devices. In this work, a set of electric-field-gradient-dependent carrier trajectory tracking equations are developed and used to update the positions of carriers along the path during Simple-band Monte Carlo (SMC) simulations of APDs with non-uniform electric fields. The mean gain and excess noise results obtained from the SMC model employing these equations show good agreement with the results reported for a series of silicon diodes, including a p+n diode with steep electric field gradients. These results confirm the validity and demonstrate the feasibility of the trajectory tracking equations applied in SMC models for simulating mean gain and excess noise in APDs with non-uniform electric fields. Also, the simulation results of mean gain, excess noise, and carrier ionization positions obtained from the SMC model of this work agree well with those of the conventional SMC model employing the concept of a uniform electric field within a carrier free-flight. These results demonstrate that the electric field variation within a carrier free-flight has an insignificant effect on the predicted mean gain and excess noise results. Therefore, both the SMC model of this work and the conventional SMC model can be used to predict the mean gain and excess noise in APDs with highly non-uniform electric fields.

Fostering Elementary School Students' Understanding of Simple Electricity by Combining Simulation and Laboratory Activities

ERIC Educational Resources Information Center

Jaakkola, T.; Nurmi, S.

2008-01-01

Computer simulations and laboratory activities have been traditionally treated as substitute or competing methods in science teaching. The aim of this experimental study was to investigate if it would be more beneficial to combine simulation and laboratory activities than to use them separately in teaching the concepts of simple electricity. Based…

Frame analysis of UNNES electric bus chassis construction using finite element method

NASA Astrophysics Data System (ADS)

Nugroho, Untoro; Anis, Samsudin; Kusumawardani, Rini; Khoiron, Ahmad Mustamil; Maulana, Syahdan Sigit; Irvandi, Muhammad; Mashdiq, Zia Putra

2018-03-01

Designing the chassis needs to be done element simulation analysis to gain chassis strength on an electric bus. The purpose of this research is to get the results of chassis simulation on an electric bus when having load use FEM (Finite element method). This research was conduct in several stages of process, such as modeling chassis by Autodesk Inventor and finite element simulation software. The frame is going to be simulated with static loading by determine fixed support and then will be given the vertical force. The fixed on the frame is clamped at both the front and rear suspensions. After the simulation based on FEM it can conclude that frame is still under elastic zone, until the frame design is safe to use.

An Orbital Trap Mass Analyzer Using a Hybrid Magnetic-Electric Field: A Simulation Study

NASA Astrophysics Data System (ADS)

Xu, Chongsheng; Wu, Fangling; Ding, Li; Ding, Chuan-Fan

2018-03-01

An orbital ion trap mass analyzer employing hybrid magnetic-electric field was designed and simulated. The trap has a rotational symmetrical structure and the hybrid trapping field was created in a toroidal space between 12 pairs of sector detection electrodes. Ion injection and ion orbital motion inside the trap were simulated using SIMION 8.1 with a user Lua program, and the required electric and magnetic field were investigated. The image charge signal can be picked up by the 12 pairs of detection electrodes and the mass resolution was evaluated using FFT. The simulated resolving power for the optimized configuration over 79,000 FWHM was obtained at the magnetic induction intensity of 0.5 Tesla in the simulation. [Figure not available: see fulltext.

USING TIME VARIANT VOLTAGE TO CALCULATE ENERGY CONSUMPTION AND POWER USE OF BUILDING SYSTEMS

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

Makhmalbaf, Atefe; Augenbroe , Godfried

2015-12-09

Buildings are the main consumers of electricity across the world. However, in the research and studies related to building performance assessment, the focus has been on evaluating the energy efficiency of buildings whereas the instantaneous power efficiency has been overlooked as an important aspect of total energy consumption. As a result, we never developed adequate models that capture both thermal and electrical characteristics (e.g., voltage) of building systems to assess the impact of variations in the power system and emerging technologies of the smart grid on buildings energy and power performance and vice versa. This paper argues that the powermore » performance of buildings as a function of electrical parameters should be evaluated in addition to systems’ mechanical and thermal behavior. The main advantage of capturing electrical behavior of building load is to better understand instantaneous power consumption and more importantly to control it. Voltage is one of the electrical parameters that can be used to describe load. Hence, voltage dependent power models are constructed in this work and they are coupled with existing thermal energy models. Lack of models that describe electrical behavior of systems also adds to the uncertainty of energy consumption calculations carried out in building energy simulation tools such as EnergyPlus, a common building energy modeling and simulation tool. To integrate voltage-dependent power models with thermal models, the thermal cycle (operation mode) of each system was fed into the voltage-based electrical model. Energy consumption of systems used in this study were simulated using EnergyPlus. Simulated results were then compared with estimated and measured power data. The mean square error (MSE) between simulated, estimated, and measured values were calculated. Results indicate that estimated power has lower MSE when compared with measured data than simulated results. Results discussed in this paper will illustrate the significance of enhancing building energy models with electrical characteristics. This would support different studies such as those related to modernization of the power system that require micro scale building-grid interaction, evaluating building energy efficiency with power efficiency considerations, and also design and control decisions that rely on accuracy of building energy simulation results.« less

Comprehensive photonics-electronics convergent simulation and its application to high-speed electronic circuit integration on a Si/Ge photonic chip

NASA Astrophysics Data System (ADS)

Takeda, Kotaro; Honda, Kentaro; Takeya, Tsutomu; Okazaki, Kota; Hiraki, Tatsurou; Tsuchizawa, Tai; Nishi, Hidetaka; Kou, Rai; Fukuda, Hiroshi; Usui, Mitsuo; Nosaka, Hideyuki; Yamamoto, Tsuyoshi; Yamada, Koji

2015-01-01

We developed a design technique for a photonics-electronics convergence system by using an equivalent circuit of optical devices in an electrical circuit simulator. We used the transfer matrix method to calculate the response of an optical device. This method used physical parameters and dimensions of optical devices as calculation parameters to design a device in the electrical circuit simulator. It also used an intermediate frequency to express the wavelength dependence of optical devices. By using both techniques, we simulated bit error rates and eye diagrams of optical and electrical integrated circuits and calculated influences of device structure change and wavelength shift penalty.

Measuring the effects of spectral smearing and enhancement on speech recognition in noise for adults and children

PubMed Central

Nittrouer, Susan; Tarr, Eric; Wucinich, Taylor; Moberly, Aaron C.; Lowenstein, Joanna H.

2015-01-01

Broadened auditory filters associated with sensorineural hearing loss have clearly been shown to diminish speech recognition in noise for adults, but far less is known about potential effects for children. This study examined speech recognition in noise for adults and children using simulated auditory filters of different widths. Specifically, 5 groups (20 listeners each) of adults or children (5 and 7 yrs), were asked to recognize sentences in speech-shaped noise. Seven-year-olds listened at 0 dB signal-to-noise ratio (SNR) only; 5-yr-olds listened at +3 or 0 dB SNR; and adults listened at 0 or −3 dB SNR. Sentence materials were processed both to smear the speech spectrum (i.e., simulate broadened filters), and to enhance the spectrum (i.e., simulate narrowed filters). Results showed: (1) Spectral smearing diminished recognition for listeners of all ages; (2) spectral enhancement did not improve recognition, and in fact diminished it somewhat; and (3) interactions were observed between smearing and SNR, but only for adults. That interaction made age effects difficult to gauge. Nonetheless, it was concluded that efforts to diagnose the extent of broadening of auditory filters and to develop techniques to correct this condition could benefit patients with hearing loss, especially children. PMID:25920851

Reverberation time influences musical enjoyment with cochlear implants.

PubMed

Certo, Michael V; Kohlberg, Gavriel D; Chari, Divya A; Mancuso, Dean M; Lalwani, Anil K

2015-02-01

To identify factors that enhance the enjoyment of music in cochlear implant (CI) recipients. Specifically, we assessed the hypothesis that variations in reverberation time (RT60) may be linked to variations in the level of musical enjoyment in CI users. Prospective analysis of music enjoyment in normal-hearing individuals. Single tertiary academic medical center. Normal-hearing adults (N = 20) were asked to rate a novel 20-second melody on three enjoyment modalities: musicality, pleasantness, and naturalness. Subjective rating of music excerpts. Participants listened to seven different instruments play the melody, each with five levels (0.2, 1.6, 3.0, 5.0, 10.0 s) of RT60, both with and without CI simulation processing. Linear regression analysis with analysis of variance was used to assess the impact of RT60 on music enjoyment. Without CI simulation, music samples with RT60 = 3.0 seconds were ranked most pleasant and most musical, whereas those with RT60 = 1.6 seconds and RT60 = 3.0 seconds were ranked equally most natural (all p < 0.05). With CI simulation, music samples with RT60 = 0.2 seconds were ranked most pleasant, most musical, and most natural (all p < 0.05). Samples without CI simulation show a preference for middle-range RT60, whereas samples with CI simulation show a negative linear relationship between RT60 and musical enjoyment, with preference for minimal reverberation. Minimization of RT60 may be a useful strategy for increasing musical enjoyment under CI conditions, both in altering existing music as well as in composition of new music.

3D PIC-MCC simulations of positive streamers in air gaps

NASA Astrophysics Data System (ADS)

Jiang, M.; Li, Y.; Wang, H.; Liu, C.

2017-10-01

Simulation of positive streamer evolution is important for understanding the microscopic physical process in discharges. Simulations described in this paper are done using a 3D Particle-In-Cell, Monte-Carlo-Collision code with photoionization. Three phases of a positive streamer evolution, identified as initiation, propagation, and branching are studied during simulations. A homogeneous electric field is applied between parallel-flat electrodes forming a millimeter air gap to make simulations and analysis more simple and general. Free electrons created by the photoionization process determine initiation, propagation, and branching of the streamers. Electron avalanches form a positive streamer tip, when the space charge of ions at the positive tip dominates the local electric field. The propagation of the positive tip toward a cathode is the result of combinations of the positive tip and secondary avalanches ahead of it. A curved feather-like channel is formed without obvious branches when the electric field between electrodes is 50 kV/cm. However, a channel is formed with obvious branches when the electric field increases up to 60 kV/cm. In contrast to the branches around a sharp needle electrode, branches near the flat anode are formed at a certain distance away from it. Simulated parameters of the streamer such as diameter, maximum electric field, propagation velocity, and electron density at the streamer tip are in a good agreement with those published earlier.

The General-Use Nodal Network Solver (GUNNS) Modeling Package for Space Vehicle Flow System Simulation

NASA Technical Reports Server (NTRS)

Harvey, Jason; Moore, Michael

2013-01-01

The General-Use Nodal Network Solver (GUNNS) is a modeling software package that combines nodal analysis and the hydraulic-electric analogy to simulate fluid, electrical, and thermal flow systems. GUNNS is developed by L-3 Communications under the TS21 (Training Systems for the 21st Century) project for NASA Johnson Space Center (JSC), primarily for use in space vehicle training simulators at JSC. It has sufficient compactness and fidelity to model the fluid, electrical, and thermal aspects of space vehicles in real-time simulations running on commodity workstations, for vehicle crew and flight controller training. It has a reusable and flexible component and system design, and a Graphical User Interface (GUI), providing capability for rapid GUI-based simulator development, ease of maintenance, and associated cost savings. GUNNS is optimized for NASA's Trick simulation environment, but can be run independently of Trick.

An Investigation of Spatial Hearing in Children with Normal Hearing and with Cochlear Implants and the Impact of Executive Function

NASA Astrophysics Data System (ADS)

Misurelli, Sara M.

The ability to analyze an "auditory scene"---that is, to selectively attend to a target source while simultaneously segregating and ignoring distracting information---is one of the most important and complex skills utilized by normal hearing (NH) adults. The NH adult auditory system and brain work rather well to segregate auditory sources in adverse environments. However, for some children and individuals with hearing loss, selectively attending to one source in noisy environments can be extremely challenging. In a normal auditory system, information arriving at each ear is integrated, and thus these binaural cues aid in speech understanding in noise. A growing number of individuals who are deaf now receive cochlear implants (CIs), which supply hearing through electrical stimulation to the auditory nerve. In particular, bilateral cochlear implants (BICIs) are now becoming more prevalent, especially in children. However, because CI sound processing lacks both fine structure cues and coordination between stimulation at the two ears, binaural cues may either be absent or inconsistent. For children with NH and with BiCIs, this difficulty in segregating sources is of particular concern because their learning and development commonly occurs within the context of complex auditory environments. This dissertation intends to explore and understand the ability of children with NH and with BiCIs to function in everyday noisy environments. The goals of this work are to (1) Investigate source segregation abilities in children with NH and with BiCIs; (2) Examine the effect of target-interferer similarity and the benefits of source segregation for children with NH and with BiCIs; (3) Investigate measures of executive function that may predict performance in complex and realistic auditory tasks of source segregation for listeners with NH; and (4) Examine source segregation abilities in NH listeners, from school-age to adults.

Influence and Correction from the Human Body on the Measurement of a Power-Frequency Electric Field Sensor

PubMed Central

Xiao, Dongping; Liu, Huaitong; Zhou, Qiang; Xie, Yutong; Ma, Qichao

2016-01-01

According to the operating specifications of existing electric field measuring instruments, measuring technicians must be located far from the instruments to eliminate the influence of the human body occupancy on a spatial electric field. Nevertheless, in order to develop a portable safety protection instrument with an effective electric field warning function for working staff in a high-voltage environment, it is necessary to study the influence of an approaching human body on the measurement of an electric field and to correct the measurement results. A single-shaft electric field measuring instrument called the Type LP-2000, which was developed by our research team, is used as the research object in this study. First, we explain the principle of electric field measurement and describe the capacitance effect produced by the human body. Through a theoretical analysis, we show that the measured electric field value decreases as a human body approaches. Their relationship is linearly proportional. Then, the ratio is identified as a correction coefficient to correct for the influence of human body proximity. The conclusion drawn from the theoretical analysis is proved via simulation. The correction coefficient kb = 1.8010 is obtained on the basis of the linear fitting of simulated data. Finally, a physical experiment is performed. When no human is present, we compare the results from the Type LP-2000 measured with Narda EFA-300 and the simulated value to verify the accuracy of the Type LP-2000. For the case of an approaching human body, the correction coefficient kb* = 1.9094 is obtained by comparing the data measured with the Type LP-2000 to the simulated value. The correction coefficient obtained from the experiment (i.e., kb*) is highly consistent with that obtained from the simulation (i.e., kb). Two experimental programs are set; under these programs, the excitation voltages and distance measuring points are regulated to produce different electric field intensities. Using kb = 1.9094, the corrected measurement of electric field intensity can accurately reflect the original environmental electric field intensity, and the maximal error is less than 6% in all the data comparisons. These results verify the effectiveness of our proposed method. PMID:27294936

Influence and Correction from the Human Body on the Measurement of a Power-Frequency Electric Field Sensor.

PubMed

Xiao, Dongping; Liu, Huaitong; Zhou, Qiang; Xie, Yutong; Ma, Qichao

2016-06-10

According to the operating specifications of existing electric field measuring instruments, measuring technicians must be located far from the instruments to eliminate the influence of the human body occupancy on a spatial electric field. Nevertheless, in order to develop a portable safety protection instrument with an effective electric field warning function for working staff in a high-voltage environment, it is necessary to study the influence of an approaching human body on the measurement of an electric field and to correct the measurement results. A single-shaft electric field measuring instrument called the Type LP-2000, which was developed by our research team, is used as the research object in this study. First, we explain the principle of electric field measurement and describe the capacitance effect produced by the human body. Through a theoretical analysis, we show that the measured electric field value decreases as a human body approaches. Their relationship is linearly proportional. Then, the ratio is identified as a correction coefficient to correct for the influence of human body proximity. The conclusion drawn from the theoretical analysis is proved via simulation. The correction coefficient kb = 1.8010 is obtained on the basis of the linear fitting of simulated data. Finally, a physical experiment is performed. When no human is present, we compare the results from the Type LP-2000 measured with Narda EFA-300 and the simulated value to verify the accuracy of the Type LP-2000. For the case of an approaching human body, the correction coefficient kb* = 1.9094 is obtained by comparing the data measured with the Type LP-2000 to the simulated value. The correction coefficient obtained from the experiment (i.e., kb*) is highly consistent with that obtained from the simulation (i.e., kb). Two experimental programs are set; under these programs, the excitation voltages and distance measuring points are regulated to produce different electric field intensities. Using kb = 1.9094, the corrected measurement of electric field intensity can accurately reflect the original environmental electric field intensity, and the maximal error is less than 6% in all the data comparisons. These results verify the effectiveness of our proposed method.

Effect of Precipitating Electrons on Stormtime Inner Magnetospheric Electric Fields during the 17 March 2013 Storm

NASA Astrophysics Data System (ADS)

Chen, M.; Lemon, C. L.; Sazykin, S. Y.; Wolf, R.; Hecht, J. H.; Walterscheid, R. L.; Boyd, A. J.; Turner, D. L.

2015-12-01

We investigate how scattering of electrons by waves in the plasma sheet and plasmasphere affects precipitating energy flux distributions and how the precipitating electrons modify the ionospheric conductivity and electric potentials during the large 17 March 2013 magnetic storm. Of particular interest is how electron precipitation in the evening sector affects the development of the Sub-auroral Polarization Stream (SAPS) electric field that is observed at sub-auroral latitudes in that sector. Our approach is to use the magnetically and electrically self-consistent Rice Convection Model - Equilibrium (RCM-E) of the inner magnetosphere to simulate the stormtime precipitating electron distributions and the electric field. We use parameterized rates of whistler-generated electron pitch-angle scattering from Orlova and Shprits [JGR, 2014] that depend on equatorial radial distance, magnetic activity (Kp), and magnetic local time (MLT) outside the simulated plasmasphere. Inside the plasmasphere, parameterized scattering rates due to hiss [Orlova et al., GRL, 2014] are used. We compare simulated trapped and precipitating electron flux distributions with measurements from Van Allen Probes/MagEIS, POES/TED and MEPED, respectively, to validate the electron loss model. Ground-based (SuperDARN) and in-situ (Van Allen Probes/EFW) observations of electric fields are compared with the simulation results. We discuss the effect of precipitating electrons on the SAPS and inner magnetospheric electric field through the data-model comparisons.

The Modern Cochlear Implant: A Triumph of Biomedical Engineering and the First Substantial Restoration of Human Sense Using a Medical Intervention.

PubMed

Wilson, Blake S

2017-01-01

Even as recently as the mid-1980s, many experts in otology and auditory science thought that restoration of useful hearing with crude and pervasive electrical stimulation of the cochlea was a fool's dream. The esteemed Prof. Rainer Klinke from Frankfurt (Figure 1) was among the chorus of critics, asserting in 1978 that "from a physiological point of view, cochlear implants will not work." Many others made similar categorical statements.

Bulletin of Prosthetics Research. Rehabilitative Engineering Research and Development, Volume 18, Number 2, Fall 1981,

DTIC Science & Technology

1981-01-01

of 140 beats per minute Upper limb prosthetic terminal devices have remained un- could either crutch walk at 60 meters per minute or run at 134...Responses During Binaural Stimulation, TN. Decker and S.W. Howe; J. Functional Effectiveness of a Myo-Electric Prosthesis Compared Acoust. Soc. Amer., 69(4...were whether the aid(s) should be fitted monaurally, binaurally or fitted with hearing aids. Of these, roughly 9,000 were CROS. About 95 percent of

Is There a Shortage of Computer Programmers/Systems Analysts? An Examination of the Empirical Evidence.

DTIC Science & Technology

1990-09-01

to own a Mercedes Benz . However, based on the market determined price few people are willing to pay for one. Yet, we don’t hear complaints that there...of Electrical and Electronic En§±neers, Fox Morris Personnel Consultants, The San Francisco Newspapers Advertising department and other sources. The...conducted in 12 December 1980 among 20 top metro markets revealed that companies across the board plan to increase their hiring in 1981 by anywhere from 10

Nuclear electric power sources

NASA Technical Reports Server (NTRS)

Singh, J. J.

1978-01-01

Measurements on radioactive commercial p-n junction silicon cells show that these units are capable of delivering several hundred microwatts per curie of Am-241 alpha source, indicating their usefulness in such electronic devices as hearing aids, heart pacemakers, electronic watches, delay timers and nuclear dosimeter chargers. It is concluded that the Am-241 sources are superior to the beta sources used previously, because of higher alpha specific ionization and simultaneous production of low energy photons which are easily converted into photoelectrons for additional power.

Simulation of an Asynchronous Machine by using a Pseudo Bond Graph

NASA Astrophysics Data System (ADS)

Romero, Gregorio; Felez, Jesus; Maroto, Joaquin; Martinez, M. Luisa

2008-11-01

For engineers, computer simulation, is a basic tool since it enables them to understand how systems work without actually needing to see them. They can learn how they work in different circumstances and optimize their design with considerably less cost in terms of time and money than if they had to carry out tests on a physical system. However, if computer simulation is to be reliable it is essential for the simulation model to be validated. There is a wide range of commercial brands on the market offering products for electrical domain simulation (SPICE, LabVIEW PSCAD,Dymola, Simulink, Simplorer,...). These are powerful tools, but require the engineer to have a perfect knowledge of the electrical field. This paper shows an alternative methodology to can simulate an asynchronous machine using the multidomain Bond Graph technique and apply it in any program that permit the simulation of models based in this technique; no extraordinary knowledge of this technique and electric field are required to understand the process .

Mechanical and electrical tuning in a tonotopically organized insect ear

NASA Astrophysics Data System (ADS)

Hummel, Jennifer; Schöneich, Stefan; Hedwig, Berthold; Kössl, Manfred; Nowotny, Manuela

2015-12-01

The high-frequency hearing organ of bushcrickets - the crista acustica (CA) - is tonotopically organized. Details about the mechano-electrical transduction mechanisms within the sensory-cell complex, however, remain unknown. In the recent study, we investigated and compared the anatomical, mechanical and electrophysiological properties of the CA and reveal a strong correlation of the mechanical and neuronal frequency tuning, which is supported by an anatomical gradient along the CA. Only in the distal high-frequency region of the CA a discrepancy between a strong mechanical response to low frequencies <30 kHz and a neuronal response that was restricted to frequencies >30 kHz was found. Therefore, we suggest that there might be additional intrinsic tuning mechanisms in the sensory cells of the distal region to distinguish the frequency content of sound.

A flight simulator control system using electric torque motors

NASA Technical Reports Server (NTRS)

Musick, R. O.; Wagner, C. A.

1975-01-01

Control systems are required in flight simulators to provide representative stick and rudder pedal characteristics. A system has been developed that uses electric dc torque motors instead of the more common hydraulic actuators. The torque motor system overcomes certain disadvantages of hydraulic systems, such as high cost, high power consumption, noise, oil leaks, and safety problems. A description of the torque motor system is presented, including both electrical and mechanical design as well as performance characteristics. The system develops forces sufficiently high for most simulations, and is physically small and light enough to be used in most motion-base cockpits.

On the road performance tests of electric test vehicle for correlation with road load simulator

NASA Technical Reports Server (NTRS)

Dustin, M. O.; Slavik, R. J.

1982-01-01

A dynamometer (road load simulator) is used to test and evaluate electric vehicle propulsion systems. To improve correlation between system tests on the road load simulator and on the road, similar performance tests are conducted using the same vehicle. The results of track tests on the electric propulsion system test vehicle are described. The tests include range at constant speeds and over SAE J227a driving cycles, maximum accelerations, maximum gradability, and tire rolling resistance determination. Road power requirements and energy consumption were also determined from coast down tests.

Lenard-Balescu calculations and classical molecular dynamics simulations of electrical and thermal conductivities of hydrogen plasmas

DOE PAGES

Whitley, Heather D.; Scullard, Christian R.; Benedict, Lorin X.; ...

2014-12-04

Here, we present a discussion of kinetic theory treatments of linear electrical and thermal transport in hydrogen plasmas, for a regime of interest to inertial confinement fusion applications. In order to assess the accuracy of one of the more involved of these approaches, classical Lenard-Balescu theory, we perform classical molecular dynamics simulations of hydrogen plasmas using 2-body quantum statistical potentials and compute both electrical and thermal conductivity from out particle trajectories using the Kubo approach. Our classical Lenard-Balescu results employing the identical statistical potentials agree well with the simulations.

Effects of High-Rate Pulse Trains on Electrode Discrimination in Cochlear Implant Users

PubMed Central

Runge-Samuelson, Christina L.

2009-01-01

Overcoming issues related to abnormally high neural synchrony in response to electrical stimulation is one aspect in improving hearing with a cochlear implant. Desynchronization of electrical stimuli have shown benefits in neural encoding of electrical signals and improvements in psychophysical tasks. In the present study, 10 participants with either CII or HiRes 90k Advanced Bionics devices were tested for the effects of desynchronizing constant-amplitude high-rate (5,000 Hz) pulse trains on electrode discrimination of sinusoidal stimuli (1,000 Hz). When averaged across the sinusoidal dynamic range, overall improvements in electrode discrimination with high-rate pulses were found for 8 of 10 participants. This effect was significant for the group (p = .003). Nonmonotonic patterns of electrode discrimination as a function of sinusoidal stimulation level were observed. By providing additional spectral channels, it is possible that clinical implementation of constant-amplitude high-rate pulse trains in a signal processing strategy may improve performance with the device. PMID:19447763

Flexoelectricity in two-dimensional crystalline and biological membranes

NASA Astrophysics Data System (ADS)

Ahmadpoor, Fatemeh; Sharma, Pradeep

2015-10-01

The ability of a material to convert electrical stimuli into mechanical deformation, i.e. piezoelectricity, is a remarkable property of a rather small subset of insulating materials. The phenomenon of flexoelectricity, on the other hand, is universal. All dielectrics exhibit the flexoelectric effect whereby non-uniform strain (or strain gradients) can polarize the material and conversely non-uniform electric fields may cause mechanical deformation. The flexoelectric effect is strongly enhanced at the nanoscale and accordingly, all two-dimensional membranes of atomistic scale thickness exhibit a strong two-way coupling between the curvature and electric field. In this review, we highlight the recent advances made in our understanding of flexoelectricity in two-dimensional (2D) membranes--whether the crystalline ones such as dielectric graphene nanoribbons or the soft lipid bilayer membranes that are ubiquitous in biology. Aside from the fundamental mechanisms, phenomenology, and recent findings, we focus on rapidly emerging directions in this field and discuss applications such as energy harvesting, understanding of the mammalian hearing mechanism and ion transport among others.

The Role of Visual Speech Information in Supporting Perceptual Learning of Degraded Speech

ERIC Educational Resources Information Center

Wayne, Rachel V.; Johnsrude, Ingrid S.

2012-01-01

Following cochlear implantation, hearing-impaired listeners must adapt to speech as heard through their prosthesis. Visual speech information (VSI; the lip and facial movements of speech) is typically available in everyday conversation. Here, we investigate whether learning to understand a popular auditory simulation of speech as transduced by a…

Factors affecting credibility in a simulated sexual harassment hearing.

PubMed

Gibbs, M; Sigal, J; Friedman, C R; Orosy-fildes, C

1995-12-01

This paper presents two studies investigating judgments in a simulated sexual harassment hearing in which 240 male and female undergraduates participated. The transcript presented a female student's allegations of sexual harassment against a male professor. In the first experiment, 4 versions of a transcript were created, varying the aggressiveness of the attack on the female student complainant and the status of the accused professor. The findings supported the hypothesis that an aggressive attack negatively affects believability of the victim. The findings are also consistent with previous studies, which found out that denial was an effective technique for handling attacks. In the second experiment, the case was modified as to the emotionality of both the victim and the accused and the time of the between the occurrence and the reporting of the alleged harassment incident (1 month vs. 6 months). The results indicated that emotionality was important to decisions about the severity of punishment and guilt; when the victim was emotional, the defendant was punished more severely. Both experiments indicated that process variables (e.g., aggressiveness of attack) might be important in the perception of sexual harassment.

Electric Field Distribution in High Voltage Power Modules Using Finite Element Simulations

NASA Astrophysics Data System (ADS)

Wang, Zhao; Liu, Yaoning

2018-03-01

With the development of the high voltage insulated gate bipolar transistor (IGBT) power module, it leads to serious problems concerning the electric field insulation. The electric field capabilities of the silicone gels used in the power module encapsulation directly affect the module insulation. Some solutions have been developed to optimize the electric field and reliability. In this letter, the finite element simulation was used to analyze and localize the maximum electric field position; solutions were proposed to improve the module insulation. It’s demonstrated that BaTiO3 silicone composite is a promising insulation material for high voltage power device.

Three-Dimensional Finite-Element Simulation for a Thermoelectric Generator Module

NASA Astrophysics Data System (ADS)

Hu, Xiaokai; Takazawa, Hiroyuki; Nagase, Kazuo; Ohta, Michihiro; Yamamoto, Atsushi

2015-10-01

A three-dimensional closed-circuit numerical model of a thermoelectric generator (TEG) module has been constructed with COMSOL® Multiphysics to verify a module test system. The Seebeck, Peltier, and Thomson effects and Joule heating are included in the thermoelectric conversion model. The TEG model is employed to simulate the operation of a 16-leg TEG module based on bismuth telluride with temperature-dependent material properties. The module is mounted on a test platform, and simulated by combining the heat conduction process and thermoelectric conversion process. Simulation results are obtained for the terminal voltage, output power, heat flow, and efficiency as functions of the electric current; the results are compared with measurement data. The Joule and Thomson heats in all the thermoelectric legs, as functions of the electric current, are calculated by finite-element volume integration over the entire legs. The Peltier heat being pumped at the hot side and released at the cold side of the module are also presented in relation to the electric current. The energy balance relations between heat and electricity are verified to support the simulation.

Development and Buildup of a Stirling Radioisotope Generator Electrical Simulator

NASA Technical Reports Server (NTRS)

Prokop, Norman F.; Krasowski, Michael J.; Greer, Lawrence C.; Flatico, Joseph M.; Spina, Dan C.

2008-01-01

This paper describes the development of a Stirling Radioisotope Generator (SRG) Simulator for use in a prototype lunar robotic rover. The SRG developed at NASA Glenn Research Center (GRC) is a promising power source for the robotic exploration of the sunless areas of the moon. The simulator designed provides a power output similar to the SRG output of 5.7 A at 28 Vdc, while using ac wall power as the input power source. The designed electrical simulator provides rover developers the physical and electrical constraints of the SRG supporting parallel development of the SRG and rover. Parallel development allows the rover design team to embrace the SRG s unique constraints while development of the SRG is continued to a flight qualified version.

Effectiveness of Dry Cell Microscopic Simulation (DCMS) to Promote Conceptual Understanding about Battery

NASA Astrophysics Data System (ADS)

Catur Wibowo, Firmanul; Suhandi, Andi; Rusdiana, Dadi; Samsudin, Achmad; Rahmi Darman, Dina; Faizin, M. Noor; Wiyanto; Supriyatman; Permanasari, Anna; Kaniawati, Ida; Setiawan, Wawan; Karyanto, Yudi; Linuwih, Suharto; Fatah, Abdul; Subali, Bambang; Hasani, Aceng; Hidayat, Sholeh

2017-07-01

Electricity is a concept that is abstract and difficult to see by eye directly, one example electric shock, but cannot see the movement of electric current so that students have difficulty by students. A computer simulation designed to improve the understanding of the concept of the workings of the dry cell (battery). This study was conducted to 82 students (aged 18-20 years) in the experimental group by learning to use the Dry Cell Microscopic Simulation (DCMS). The result shows the improving of students’ conceptual understanding scores from post test were statistically significantly of the workings of batteries. The implication using computer simulations designed to overcome the difficulties of conceptual understanding, can effectively help students in facilitating conceptual change.

Binaural masking release in children with Down syndrome.

PubMed

Porter, Heather L; Grantham, D Wesley; Ashmead, Daniel H; Tharpe, Anne Marie

2014-01-01

Binaural hearing results in a number of listening advantages relative to monaural hearing, including enhanced hearing sensitivity and better speech understanding in adverse listening conditions. These advantages are facilitated in part by the ability to detect and use interaural cues within the central auditory system. Binaural hearing for children with Down syndrome could be impacted by multiple factors including, structural anomalies within the peripheral and central auditory system, alterations in synaptic communication, and chronic otitis media with effusion. However, binaural hearing capabilities have not been investigated in these children. This study tested the hypothesis that children with Down syndrome experience less binaural benefit than typically developing peers. Participants included children with Down syndrome aged 6 to 16 years (n = 11), typically developing children aged 3 to 12 years (n = 46), adults with Down syndrome (n = 3), and adults with no known neurological delays (n = 6). Inclusionary criteria included normal to near-normal hearing sensitivity. Two tasks were used to assess binaural ability. Masking level difference (MLD) was calculated by comparing threshold for a 500-Hz pure-tone signal in 300-Hz wide Gaussian noise for N0S0 and N0Sπ signal configurations. Binaural intelligibility level difference was calculated using simulated free-field conditions. Speech recognition threshold was measured for closed-set spondees presented from 0-degree azimuth in speech-shaped noise presented from 0-, 45- and 90-degree azimuth, respectively. The developmental ability of children with Down syndrome was estimated and information regarding history of otitis media was obtained for all child participants via parent survey. Individuals with Down syndrome had higher masked thresholds for pure-tone and speech stimuli than typically developing individuals. Children with Down syndrome had significantly smaller MLDs than typically developing children. Adults with Down syndrome and control adults had similar MLDs. Similarities in simulated spatial release from masking were observed for all groups for the experimental parameters used in this study. No association was observed for any measure of binaural ability and developmental age for children with Down syndrome. Similar group psychometric functions were observed for children with Down syndrome and typically developing children in most instances, suggesting that attentiveness and motivation contributed equally to performance for both groups on most tasks. The binaural advantages afforded to typically developing children, such as enhanced hearing sensitivity in noise, were not as robust for children with Down syndrome in this study. Children with Down syndrome experienced less binaural benefit than typically developing peers for some stimuli, suggesting that they could require more favorable signal-to-noise ratios to achieve optimal performance in some adverse listening conditions. The reduced release from masking observed for children with Down syndrome could represent a delay in ability rather than a deficit that persists into adulthood. This could have implications for the planning of interventions for individuals with Down syndrome.

Approximated affine projection algorithm for feedback cancellation in hearing aids.

PubMed

Lee, Sangmin; Kim, In-Young; Park, Young-Cheol

2007-09-01

We propose an approximated affine projection (AP) algorithm for feedback cancellation in hearing aids. It is based on the conventional approach using the Gauss-Seidel (GS) iteration, but provides more stable convergence behaviour even with small step sizes. In the proposed algorithm, a residue of the weighted error vector, instead of the current error sample, is used to provide stable convergence. A new learning rate control scheme is also applied to the proposed algorithm to prevent signal cancellation and system instability. The new scheme determines step size in proportion to the prediction factor of the input, so that adaptation is inhibited whenever tone-like signals are present in the input. Simulation results verified the efficiency of the proposed algorithm.

An RF phased array applicator designed for hyperthermia breast cancer treatments

PubMed Central

Wu, Liyong; McGough, Robert J; Arabe, Omar Ali; Samulski, Thaddeus V

2007-01-01

An RF phased array applicator has been constructed for hyperthermia treatments in the intact breast. This RF phased array consists of four antennas mounted on a Lexan water tank, and geometric focusing is employed so that each antenna points in the direction of the intended target. The operating frequency for this phased array is 140 MHz. The RF array has been characterized both by electric field measurements in a water tank and by electric field simulations using the finite-element method. The finite-element simulations are performed with HFSS software, where the mesh defined for finite-element calculations includes the geometry of the tank enclosure and four end-loaded dipole antennas. The material properties of the water tank enclosure and the antennas are also included in each simulation. The results of the finite-element simulations are compared to the measured values for this configuration, and the results, which include the effects of amplitude shading and phase shifting, show that the electric field predicted by finite-element simulations is similar to the measured field. Simulations also show that the contributions from standing waves are significant, which is consistent with measurement results. Simulated electric field and bio-heat transfer results are also computed within a simple 3D breast model. Temperature simulations show that, although peak temperatures are generated outside the simulated tumour target, this RF phased array applicator is an effective device for regional hyperthermia in the intact breast. PMID:16357427

Validated numerical simulation model of a dielectric elastomer generator

NASA Astrophysics Data System (ADS)

Foerster, Florentine; Moessinger, Holger; Schlaak, Helmut F.

2013-04-01

Dielectric elastomer generators (DEG) produce electrical energy by converting mechanical into electrical energy. Efficient operation requires homogeneous deformation of each single layer. However, by different internal and external influences like supports or the shape of a DEG the deformation will be inhomogeneous and hence negatively affect the amount of the generated electrical energy. Optimization of the deformation behavior leads to improved efficiency of the DEG and consequently to higher energy gain. In this work a numerical simulation model of a multilayer dielectric elastomer generator is developed using the FEM software ANSYS. The analyzed multilayer DEG consists of 49 active dielectric layers with layer thicknesses of 50 μm. The elastomer is silicone (PDMS) while the compliant electrodes are made of graphite powder. In the simulation the real material parameters of the PDMS and the graphite electrodes need to be included. Therefore, the mechanical and electrical material parameters of the PDMS are determined by experimental investigations of test samples while the electrode parameters are determined by numerical simulations of test samples. The numerical simulation of the DEG is carried out as coupled electro-mechanical simulation for the constant voltage energy harvesting cycle. Finally, the derived numerical simulation model is validated by comparison with analytical calculations and further simulated DEG configurations. The comparison of the determined results show good accordance with regard to the deformation of the DEG. Based on the validated model it is now possible to optimize the DEG layout for improved deformation behavior with further simulations.

A percolation approach to study the high electric field effect on electrical conductivity of insulating polymer

NASA Astrophysics Data System (ADS)

Benallou, Amina; Hadri, Baghdad; Martinez-Vega, Juan; El Islam Boukortt, Nour

2018-04-01

The effect of percolation threshold on the behaviour of electrical conductivity at high electric field of insulating polymers has been briefly investigated in literature. Sometimes the dead ends links are not taken into account in the study of the electric field effect on the electrical properties. In this work, we present a theoretical framework and Monte Carlo simulation of the behaviour of the electric conductivity at high electric field based on the percolation theory using the traps energies levels which are distributed according to distribution law (uniform, Gaussian, and power-law). When a solid insulating material is subjected to a high electric field, and during trapping mechanism the dead ends of traps affect with decreasing the electric conductivity according to the traps energies levels, the correlation length of the clusters, the length of the dead ends, and the concentration of the accessible positions for the electrons. A reasonably good agreement is obtained between simulation results and the theoretical framework.

Simulating the value of electric-vehicle-grid integration using a behaviourally realistic model

NASA Astrophysics Data System (ADS)

Wolinetz, Michael; Axsen, Jonn; Peters, Jotham; Crawford, Curran

2018-02-01

Vehicle-grid integration (VGI) uses the interaction between electric vehicles and the electrical grid to provide benefits that may include reducing the cost of using intermittent renwable electricity or providing a financial incentive for electric vehicle ownerhip. However, studies that estimate the value of VGI benefits have largely ignored how consumer behaviour will affect the magnitude of the impact. Here, we simulate the long-term impact of VGI using behaviourally realistic and empirically derived models of vehicle adoption and charging combined with an electricity system model. We focus on the case where a central entity manages the charging rate and timing for participating electric vehicles. VGI is found not to increase the adoption of electric vehicles, but does have a a small beneficial impact on electricity prices. By 2050, VGI reduces wholesale electricity prices by 0.6-0.7% (0.7 MWh-1, 2010 CAD) relative to an equivalent scenario without VGI. Excluding consumer behaviour from the analysis inflates the value of VGI.

Design and Implementation of Effective Electrical Power System for Surya Satellite-1

NASA Astrophysics Data System (ADS)

Sulistya, A. H.; Hasbi, W.; Muhida, R.

2018-05-01

Surya Satellite-1 is a nanosatellite developed by students of Surya University. The subject of this paper is the design and implementation of effective electrical power system for Surya Satellite 1. The electrical power system role is to supply other systems of the satellite with appropriate electrical power. First, the requirements of the electrical power system are defined. The architecture of the electrical power system is then designed to build the prototype. The orbit simulation is calculated to predict the power production. When prototype test and simulation data is gained, we make an operation scenario to keep the produced power and the consumed power in balance. The design of the modules of the electrical power system is carried out with triple junction solar cells, lithium ion batteries, maximum power point trackers, charging controllers, power distributions, and protection systems. Finally, the prototypes of the electrical power system are presented.

Computational Evaluation of Cochlear Implant Surgery Outcomes Accounting for Uncertainty and Parameter Variability.

PubMed

Mangado, Nerea; Pons-Prats, Jordi; Coma, Martí; Mistrík, Pavel; Piella, Gemma; Ceresa, Mario; González Ballester, Miguel Á

2018-01-01

Cochlear implantation (CI) is a complex surgical procedure that restores hearing in patients with severe deafness. The successful outcome of the implanted device relies on a group of factors, some of them unpredictable or difficult to control. Uncertainties on the electrode array position and the electrical properties of the bone make it difficult to accurately compute the current propagation delivered by the implant and the resulting neural activation. In this context, we use uncertainty quantification methods to explore how these uncertainties propagate through all the stages of CI computational simulations. To this end, we employ an automatic framework, encompassing from the finite element generation of CI models to the assessment of the neural response induced by the implant stimulation. To estimate the confidence intervals of the simulated neural response, we propose two approaches. First, we encode the variability of the cochlear morphology among the population through a statistical shape model. This allows us to generate a population of virtual patients using Monte Carlo sampling and to assign to each of them a set of parameter values according to a statistical distribution. The framework is implemented and parallelized in a High Throughput Computing environment that enables to maximize the available computing resources. Secondly, we perform a patient-specific study to evaluate the computed neural response to seek the optimal post-implantation stimulus levels. Considering a single cochlear morphology, the uncertainty in tissue electrical resistivity and surgical insertion parameters is propagated using the Probabilistic Collocation method, which reduces the number of samples to evaluate. Results show that bone resistivity has the highest influence on CI outcomes. In conjunction with the variability of the cochlear length, worst outcomes are obtained for small cochleae with high resistivity values. However, the effect of the surgical insertion length on the CI outcomes could not be clearly observed, since its impact may be concealed by the other considered parameters. Whereas the Monte Carlo approach implies a high computational cost, Probabilistic Collocation presents a suitable trade-off between precision and computational time. Results suggest that the proposed framework has a great potential to help in both surgical planning decisions and in the audiological setting process.

Study of SF6 gas decomposition products based on spectroscopy technology

NASA Astrophysics Data System (ADS)

Cai, Ji-xing; Na, Yan-xiang; Ni, Wei-yuan; Li, Guo-wei; Feng, Ke-cheng; Song, Gui-cai

2011-08-01

With the rapid development of power industry, the number of SF6 electrical equipment are increasing, it has gradually replaced the traditional insulating oil material as insulation and arc media in the high-voltage electrical equipment. Pure SF6 gas has excellent insulating properties and arc characteristics; however, under the effect of the strong arc, SF6 gas will decompose and generate toxic substances, then corroding electrical equipment, thereby affecting the insulation and arc ability of electrical equipment. If excessive levels of impurities in the gas that will seriously affect the mechanical properties, breaking performance and electrical performance of electrical equipment, it will cause many serious consequences, even threaten the safe operation of the grid. This paper main analyzes the basic properties of SF6 gas and the basic situation of decomposition in the discharge conditions, in order to simulate the actual high-voltage electrical equipment, designed and produced a simulation device that can simulate the decomposition of SF6 gas under a high voltage discharge, and using fourier transform infrared spectroscopy to analyze the sample that produced by the simulation device. The result show that the main discharge decomposition product is SO2F2 (sulfuryl fluoride), the substance can react with water and generate corrosive H2SO4(sulfuric acid) and HF (hydrogen fluoride), also found that the increase in the number with the discharge, SO2F2concentration levels are on the rise. Therefore, the material can be used as one of the main characteristic gases to determine the SF6 electrical equipment failure, and to monitor their concentration levels.

Efferent feedback can explain many hearing phenomena

NASA Astrophysics Data System (ADS)

Holmes, W. Harvey; Flax, Matthew R.

2015-12-01

The mixed mode cochlear amplifier (MMCA) model was presented at the last Mechanics of Hearing workshop [4]. The MMCA consists principally of a nonlinear feedback loop formed when an efferent-controlled outer hair cell (OHC) is combined with the cochlear mechanics and the rest of the relevant neurobiology. Essential elements of this model are efferent control of the OHC motility and a delay in the feedback to the OHC. The input to the MMCA is the passive travelling wave. In the MMCA amplification is localized where both the neural and tuned mechanical systems meet in the Organ of Corti (OoC). The simplest model based on this idea is a nonlinear delay line resonator (DLR), which is mathematically described by a nonlinear delay-differential equation (DDE). This model predicts possible Hopf bifurcations and exhibits its most interesting behaviour when operating near a bifurcation. This contribution presents some simulation results using the DLR model. These show that various observed hearing phenomena can be accounted for by this model, at least qualitatively, including compression effects, two-tone suppression and some forms of otoacoustic emissions (OAEs).

Predicting academic success among deaf college students.

PubMed

Convertino, Carol M; Marschark, Marc; Sapere, Patricia; Sarchet, Thomastine; Zupan, Megan

2009-01-01

For both practical and theoretical reasons, educators and educational researchers seek to determine predictors of academic success for students at different levels and from different populations. Studies involving hearing students at the postsecondary level have documented significant predictors of success relating to various demographic factors, school experience, and prior academic attainment. Studies involving deaf and hard-of-hearing students have focused primarily on younger students and variables such as degree of hearing loss, use of cochlear implants, educational placement, and communication factors-although these typically are considered only one or two at a time. The present investigation utilizes data from 10 previous experiments, all using the same paradigm, in an attempt to discern significant predictors of readiness for college (utilizing college entrance examination scores) and classroom learning at the college level (utilizing scores from tests in simulated classrooms). Academic preparation was a clear and consistent predictor in both domains, but the audiological and communication variables examined were not. Communication variables that were significant reflected benefits of language flexibility over skills in either spoken language or American Sign Language.

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.

ERDA authorization, Fiscal Year 1977. Part I. Conservation. Hearings before the Subcommittee on Energy Research, Development and Demonstration of the Committee on Science and Technology, U. S. House of Representatives, Ninety-Fourth Congress, Second Session

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

Not Available

1976-01-01

The hearing was the first in a series of nine before the subcommittee in connection with the fiscal year 1977 ERDA authorization bill. The ERDA conservation program and its funding are reviewed and Representative Ray Thornton, presiding, announced that Congress was expected to pass significant energy conservation legislation to augment the existing ERDA program. Included here is a statement on the issue by Mr. Austin N. Heller, Asst. Administrator for Conservation, ERDA, who was accompanied by his division directors--Mr. Francis Parry, Mr. John Brogan, Dr. Maxine Savitz, Dr. John Belding, and Mr. George Murray. Another statement was presented by Rogermore » W. Sant, Asst. Administrator for Energy, FEA. Additional statements are presented in Appendix I by Mr. Lowell Endahl, National Rural Electric Cooperative Association, and Mr. Wes Uhlman, Mayor of Seattle, Wash. Additional information is presented in three other appendixes. (MCW)« less

Flexible piezoelectric energy harvesting from jaw movements

NASA Astrophysics Data System (ADS)

Delnavaz, Aidin; Voix, Jérémie

2014-10-01

Piezoelectric fiber composites (PFC) represent an interesting subset of smart materials that can function as sensor, actuator and energy converter. Despite their excellent potential for energy harvesting, very few PFC mechanisms have been developed to capture the human body power and convert it into an electric current to power wearable electronic devices. This paper provides a proof of concept for a head-mounted device with a PFC chin strap capable of harvesting energy from jaw movements. An electromechanical model based on the bond graph method is developed to predict the power output of the energy harvesting system. The optimum resistance value of the load and the best stretch ratio in the strap are also determined. A prototype was developed and tested and its performances were compared to the analytical model predictions. The proposed piezoelectric strap mechanism can be added to all types of head-mounted devices to power small-scale electronic devices such as hearing aids, electronic hearing protectors and communication earpieces.

Cochlear Implant Using Neural Prosthetics

NASA Astrophysics Data System (ADS)

Gupta, Shweta; Singh, Shashi kumar; Dubey, Pratik Kumar

2012-10-01

This research is based on neural prosthetic device. The oldest and most widely used of these electrical, and often computerized, devices is the cochlear implant, which has provided hearing to thousands of congenitally deaf people in this country. Recently, the use of the cochlear implant is expanding to the elderly, who frequently suffer major hearing loss. More cutting edge are artificial retinas, which are helping dozens of blind people see, and ìsmartî artificial arms and legs that amputees can maneuver by thoughts alone, and that feel more like real limbs.Research, which curiosity led to explore frog legs dancing during thunderstorms, a snail shapedorgan in the inner ear, and how various eye cells react to light, have fostered an understanding of how to ìtalkî to the nervous system. That understanding combined with the miniaturization of electronics and enhanced computer processing has enabled prosthetic devices that often can bridge the gap in nerve signaling that is caused by disease or injury.

Estimating potential stranded commitments for U.S. investor-owned electric utilities

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

Baxter, L.; Hirst, E.

New technologies, low natural gas prices, and federal and state utility regions are restructuring the electricity industry. Yesterday`s vertically integrated utility with a retail monopoly franchise may be a very different organization in a few years. Conferences, regulatory-commission hearings, and other industry fora are dominated by debates over the extent and form of utility deintegration, wholesale competition, and retail wheeling. A key obstacle to restructuring the electricity industry is stranded commitments. Past investments, power-purchase contracts, and public-policy-driven programs that made sense in an era of cost-of-service regulation may not be cost-effective in a competitive power market. Regulators, utilities, and othermore » parties face tough decisions concerning the mitigation and allocation of these stranded commitments. The authors developed and applied a simple method to calculate the amount of stranded commitments facing US investor-owned electric utilities. The results obtained with this method depend strongly on a few key assumptions: (1) the fraction of utility sales that is at risk with respect to competition, (2) the market price of electric generation, and (3) the number of years during which the utility would lose money because of differences between its embedded cost of production and the market price.« less

One-step fabrication of nanostructure-covered microstructures using selective aluminum anodization based on non-uniform electric field

NASA Astrophysics Data System (ADS)

Park, Yong Min; Kim, Byeong Hee; Seo, Young Ho

2016-06-01

This paper presents a selective aluminum anodization technique for the fabrication of microstructures covered by nanoscale dome structures. It is possible to fabricate bulging microstructures, utilizing the different growth rates of anodic aluminum oxide in non-uniform electric fields, because the growth rate of anodic aluminum oxide depends on the intensity of electric field, or current density. After anodizing under a non-uniform electric field, bulging microstructures covered by nanostructures were fabricated by removing the residual aluminum layer. The non-uniform electric field induced by insulative micropatterns was estimated by computational simulations and verified experimentally. Utilizing computational simulations, the intensity profile of the electric field was calculated according to the ratio of height and width of the insulative micropatterns. To compare computational simulation results and experimental results, insulative micropatterns were fabricated using SU-8 photoresist. The results verified that the shape of the bottom topology of anodic alumina was strongly dependent on the intensity profile of the applied electric field, or current density. The one-step fabrication of nanostructure-covered microstructures can be applied to various fields, such as nano-biochip and nano-optics, owing to its simplicity and cost effectiveness.

The electrical conductivity of in vivo human uterine fibroids.

PubMed

DeLonzor, Russ; Spero, Richard K; Williams, Joseph J

2011-01-01

The purpose of this study was to determine the value of electrical conductivity that can be used for numerical modelling in vivo radiofrequency ablation (RFA) treatments of human uterine fibroids. No experimental electrical conductivity data have previously been reported for human uterine fibroids. In this study electrical data (voltage) from selected in vivo clinical procedures on human uterine fibroids were used to numerically model the treatments. Measured versus calculated power dissipation profiles were compared to determine uterine fibroid electrical conductivity. Numerical simulations were conducted utilising a wide range of values for tissue thermal conductivity, heat capacity and blood perfusion coefficient. The simulations demonstrated that power dissipation was insensitive to the exact values of these parameters for the simulated geometry, treatment duration, and power level. Consequently, it was possible to determine tissue electrical conductivity without precise knowledge of the values for these parameters. Results of this study showed that an electrical conductivity for uterine fibroids of 0.305 S/m at 37°C and a temperature coefficient of 0.2%/°C can be used for modelling Radio Frequency Ablation of human uterine fibroids at a frequency of 460 kHz for temperatures from 37°C to 100°C.

Bilateral Changes of Spontaneous Activity Within the Central Auditory Pathway Upon Chronic Unilateral Intracochlear Electrical Stimulation.

PubMed

Basta, Dietmar; Götze, Romy; Gröschel, Moritz; Jansen, Sebastian; Janke, Oliver; Tzschentke, Barbara; Boyle, Patrick; Ernst, Arne

2015-12-01

In recent years, cochlear implants have been applied successfully for the treatment of unilateral hearing loss with quite surprising benefit. One reason for this successful treatment, including the relief from tinnitus, could be the normalization of spontaneous activity in the central auditory pathway because of the electrical stimulation. The present study, therefore, investigated at a cellular level, the effect of a unilateral chronic intracochlear stimulation on key structures of the central auditory pathway. Normal-hearing guinea pigs were mechanically single-sided deafened through a standard HiFocus1j electrode array (on a HiRes 90k cochlear implant) being inserted into the first turn of the cochlea. Four to five electrode contacts could be used for the stimulation. Six weeks after surgery, the speech processor (Auria) was fitted, based on tNRI values and mounted on the animal's back. The two experimental groups were stimulated 16 hours per day for 90 days, using a HiRes strategy based on different stimulation rates (low rate (275 pps/ch), high rate (5000 pps/ch)). The results were compared with those of unilateral deafened controls (implanted but not stimulated), as well as between the treatment groups. All animals experienced a standardized free field auditory environment. The low-rate group showed a significantly lower average spontaneous activity bilaterally in the dorsal cochlear nucleus and the medial geniculate body than the controls. However, there was no difference in the inferior colliculus and the primary auditory cortex. Spontaneous activity of the high-rate group was also reduced bilaterally in the dorsal cochlear nucleus and in the primary auditory cortex. No differences could be observed between the high-rate group and the controls in the contra-lateral inferior colliculus and medial geniculate body. The high-rate group showed bilaterally a higher activity in the CN and the MGB compared with the low-rate group, whereas in the IC and in the AC a trend for an opposite effect could be determined. Unilateral intracochlear electrical stimulation seems to facilitate the homeostasis of the network activity, since it decreases the spontaneous activity that is usually elevated upon deafferentiation. The electrical stimulation per se seems to be responsible for the bilateral changes described above, rather than the particular nature of the electrical stimulation (e.g., rate). The normalization effects of electrical stimulation found in the present study are of particular importance in cochlear implant recipients with single-sided deafness.

Progress in Modeling and Simulation of Batteries

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

Turner, John A

2016-01-01

Modeling and simulation of batteries, in conjunction with theory and experiment, are important research tools that offer opportunities for advancement of technologies that are critical to electric motors. The development of data from the application of these tools can provide the basis for managerial and technical decision-making. Together, these will continue to transform batteries for electric vehicles. This collection of nine papers presents the modeling and simulation of batteries and the continuing contribution being made to this impressive progress, including topics that cover: * Thermal behavior and characteristics * Battery management system design and analysis * Moderately high-fidelity 3D capabilitiesmore » * Optimization Techniques and Durability As electric vehicles continue to gain interest from manufacturers and consumers alike, improvements in economy and affordability, as well as adoption of alternative fuel sources to meet government mandates are driving battery research and development. Progress in modeling and simulation will continue to contribute to battery improvements that deliver increased power, energy storage, and durability to further enhance the appeal of electric vehicles.« less

Quasi-static time-series simulation using OpenDSS in IEEE distribution feeder model with high PV penetration and its impact on solar forecasting

NASA Astrophysics Data System (ADS)

Mohammed, Touseef Ahmed Faisal

Since 2000, renewable electricity installations in the United States (excluding hydropower) have more than tripled. Renewable electricity has grown at a compounded annual average of nearly 14% per year from 2000-2010. Wind, Concentrated Solar Power (CSP) and solar Photo Voltaic (PV) are the fastest growing renewable energy sectors. In 2010 in the U.S., solar PV grew over 71% and CSP grew by 18% from the previous year. Globally renewable electricity installations have more than quadrupled from 2000-2010. Solar PV generation grew by a factor of more than 28 between 2000 and 2010. The amount of CSP and solar PV installations are increasing on the distribution grid. These PV installations transmit electrical current from the load centers to the generating stations. But the transmission and distribution grid have been designed for uni-directional flow of electrical energy from generating stations to load centers. This causes imbalances in voltage and switchgear of the electrical circuitry. With the continuous rise in PV installations, analysis of voltage profile and penetration levels remain an active area of research. Standard distributed photovoltaic (PV) generators represented in simulation studies do not reflect the exact location and variability properties such as distance between interconnection points to substations, voltage regulators, solar irradiance and other environmental factors. Quasi-Static simulations assist in peak load planning hour and day ahead as it gives a time sequence analysis to help in generation allocation. Simulation models can be daily, hourly or yearly depending on duty cycle and dynamics of the system. High penetration of PV into the power grid changes the voltage profile and power flow dynamically in the distribution circuits due to the inherent variability of PV. There are a number of modeling and simulations tools available for the study of such high penetration PV scenarios. This thesis will specifically utilize OpenDSS, a open source Distribution System Simulator developed by Electric Power Research Institute, to simulate grid voltage profile with a large scale PV system under quasi-static time series considering variations of PV output in seconds, minutes, and the average daily load variations. A 13 bus IEEE distribution feeder model is utilized with distributed residential and commercial scale PV at different buses for simulation studies. Time series simulations are discussed for various modes of operation considering dynamic PV penetration at different time periods in a day. In addition, this thesis demonstrates simulations taking into account the presence of moving cloud for solar forecasting studies.

Simulation Tools and Techniques for Analyzing the Impacts of Photovoltaic System Integration

NASA Astrophysics Data System (ADS)

Hariri, Ali

Solar photovoltaic (PV) energy integration in distribution networks is one of the fastest growing sectors of distributed energy integration. The growth in solar PV integration is incentivized by various clean power policies, global interest in solar energy, and reduction in manufacturing and installation costs of solar energy systems. The increase in solar PV integration has raised a number of concerns regarding the potential impacts that might arise as a result of high PV penetration. Some impacts have already been recorded in networks with high PV penetration such as in China, Germany, and USA (Hawaii and California). Therefore, network planning is becoming more intricate as new technologies are integrated into the existing electric grid. The integrated new technologies pose certain compatibility concerns regarding the existing electric grid infrastructure. Therefore, PV integration impact studies are becoming more essential in order to have a better understanding of how to advance the solar PV integration efforts without introducing adverse impacts into the network. PV impact studies are important for understanding the nature of the new introduced phenomena. Understanding the nature of the potential impacts is a key factor for mitigating and accommodating for said impacts. Traditionally, electric power utilities relied on phasor-based power flow simulations for planning their electric networks. However, the conventional, commercially available, phasor-based simulation tools do not provide proper visibility across a wide spectrum of electric phenomena. Moreover, different types of simulation approaches are suitable for specific types of studies. For instance, power flow software cannot be used for studying time varying phenomena. At the same time, it is not practical to use electromagnetic transient (EMT) tools to perform power flow solutions. Therefore, some electric phenomena caused by the variability of PV generation are not visible using the conventional utility simulation software. On the other hand, EMT simulation tools provide high accuracy and visibility over a wide bandwidth of frequencies at the expense of larger processing and memory requirements, limited network size, and long simulation time. Therefore, there is a gap in simulation tools and techniques that can efficiently and effectively identify potential PV impact. New planning simulation tools are needed in order to accommodate for the simulation requirements of new integrated technologies in the electric grid. The dissertation at hand starts by identifying some of the potential impacts that are caused by high PV penetration. A phasor-based quasi-static time series (QSTS) analysis tool is developed in order to study the slow dynamics that are caused by the variations in the PV generation that lead to voltage fluctuations. Moreover, some EMT simulations are performed in order to study the impacts of PV systems on the electric network harmonic levels. These studies provide insights into the type and duration of certain impacts, as well as the conditions that may lead to adverse phenomena. In addition these studies present an idea about the type of simulation tools that are sufficient for each type of study. After identifying some of the potential impacts, certain planning tools and techniques are proposed. The potential PV impacts may cause certain utilities to refrain from integrating PV systems into their networks. However, each electric network has a certain limit beyond which the impacts become substantial and may adversely interfere with the system operation and the equipment along the feeder; this limit is referred to as the hosting limit (or hosting capacity). Therefore, it is important for utilities to identify the PV hosting limit on a specific electric network in order to safely and confidently integrate the maximum possible PV systems. In the following dissertation, two approaches have been proposed for identifying the hosing limit: 1. Analytical approach: this is a theoretical mathematical approach that demonstrated the understanding of the fundamentals of electric power system operation. It provides an easy way to estimate the maximum amount of PV power that can be injected at each node in the network. This approach has been tested and validated. 2. Stochastic simulation software approach: this approach provides a comprehensive simulation software that can be used in order to identify the PV hosting limit. The software performs a large number of stochastic simulation while varying the PV system size and location. The collected data is then analyzed for violations in the voltage levels, voltage fluctuations and reverse power flow. (Abstract shortened by ProQuest.).

Masking release with changing fundamental frequency: Electric acoustic stimulation resembles normal hearing subjects.

PubMed

Auinger, Alice Barbara; Riss, Dominik; Liepins, Rudolfs; Rader, Tobias; Keck, Tilman; Keintzel, Thomas; Kaider, Alexandra; Baumgartner, Wolf-Dieter; Gstoettner, Wolfgang; Arnoldner, Christoph

2017-07-01

It has been shown that patients with electric acoustic stimulation (EAS) perform better in noisy environments than patients with a cochlear implant (CI). One reason for this could be the preserved access to acoustic low-frequency cues including the fundamental frequency (F0). Therefore, our primary aim was to investigate whether users of EAS experience a release from masking with increasing F0 difference between target talker and masking talker. The study comprised 29 patients and consisted of three groups of subjects: EAS users, CI users and normal-hearing listeners (NH). All CI and EAS users were implanted with a MED-EL cochlear implant and had at least 12 months of experience with the implant. Speech perception was assessed with the Oldenburg sentence test (OlSa) using one sentence from the test corpus as speech masker. The F0 in this masking sentence was shifted upwards by 4, 8, or 12 semitones. For each of these masker conditions the speech reception threshold (SRT) was assessed by adaptively varying the masker level while presenting the target sentences at a fixed level. A statistically significant improvement in speech perception was found for increasing difference in F0 between target sentence and masker sentence in EAS users (p = 0.038) and in NH listeners (p = 0.003). In CI users (classic CI or EAS users with electrical stimulation only) speech perception was independent from differences in F0 between target and masker. A release from masking with increasing difference in F0 between target and masking speech was only observed in listeners and configurations in which the low-frequency region was presented acoustically. Thus, the speech information contained in the low frequencies seems to be crucial for allowing listeners to separate multiple sources. By combining acoustic and electric information, EAS users even manage tasks as complicated as segregating the audio streams from multiple talkers. Preserving the natural code, like fine-structure cues in the low-frequency region, seems to be crucial to provide CI users with the best benefit. Copyright © 2017 Elsevier B.V. All rights reserved.

Power quality analysis of DC arc furnace operation using the Bowman model for electric arc

NASA Astrophysics Data System (ADS)

Gherman, P. L.

2018-01-01

This work is about a relatively new domain. The DC electric arc is superior to the AC electric arc and it’s not used in Romania. This is why we analyzed the work functions of these furnaces by simulation and model checking of the simulation results.The conclusions are favorable, to be carried is to develop a real-time control system of steel elaboration process.

Positron Emission Tomography Imaging Reveals Auditory and Frontal Cortical Regions Involved with Speech Perception and Loudness Adaptation.

PubMed

Berding, Georg; Wilke, Florian; Rode, Thilo; Haense, Cathleen; Joseph, Gert; Meyer, Geerd J; Mamach, Martin; Lenarz, Minoo; Geworski, Lilli; Bengel, Frank M; Lenarz, Thomas; Lim, Hubert H

2015-01-01

Considerable progress has been made in the treatment of hearing loss with auditory implants. However, there are still many implanted patients that experience hearing deficiencies, such as limited speech understanding or vanishing perception with continuous stimulation (i.e., abnormal loudness adaptation). The present study aims to identify specific patterns of cerebral cortex activity involved with such deficiencies. We performed O-15-water positron emission tomography (PET) in patients implanted with electrodes within the cochlea, brainstem, or midbrain to investigate the pattern of cortical activation in response to speech or continuous multi-tone stimuli directly inputted into the implant processor that then delivered electrical patterns through those electrodes. Statistical parametric mapping was performed on a single subject basis. Better speech understanding was correlated with a larger extent of bilateral auditory cortex activation. In contrast to speech, the continuous multi-tone stimulus elicited mainly unilateral auditory cortical activity in which greater loudness adaptation corresponded to weaker activation and even deactivation. Interestingly, greater loudness adaptation was correlated with stronger activity within the ventral prefrontal cortex, which could be up-regulated to suppress the irrelevant or aberrant signals into the auditory cortex. The ability to detect these specific cortical patterns and differences across patients and stimuli demonstrates the potential for using PET to diagnose auditory function or dysfunction in implant patients, which in turn could guide the development of appropriate stimulation strategies for improving hearing rehabilitation. Beyond hearing restoration, our study also reveals a potential role of the frontal cortex in suppressing irrelevant or aberrant activity within the auditory cortex, and thus may be relevant for understanding and treating tinnitus.

Positron Emission Tomography Imaging Reveals Auditory and Frontal Cortical Regions Involved with Speech Perception and Loudness Adaptation

PubMed Central

Berding, Georg; Wilke, Florian; Rode, Thilo; Haense, Cathleen; Joseph, Gert; Meyer, Geerd J.; Mamach, Martin; Lenarz, Minoo; Geworski, Lilli; Bengel, Frank M.; Lenarz, Thomas; Lim, Hubert H.

2015-01-01

Considerable progress has been made in the treatment of hearing loss with auditory implants. However, there are still many implanted patients that experience hearing deficiencies, such as limited speech understanding or vanishing perception with continuous stimulation (i.e., abnormal loudness adaptation). The present study aims to identify specific patterns of cerebral cortex activity involved with such deficiencies. We performed O-15-water positron emission tomography (PET) in patients implanted with electrodes within the cochlea, brainstem, or midbrain to investigate the pattern of cortical activation in response to speech or continuous multi-tone stimuli directly inputted into the implant processor that then delivered electrical patterns through those electrodes. Statistical parametric mapping was performed on a single subject basis. Better speech understanding was correlated with a larger extent of bilateral auditory cortex activation. In contrast to speech, the continuous multi-tone stimulus elicited mainly unilateral auditory cortical activity in which greater loudness adaptation corresponded to weaker activation and even deactivation. Interestingly, greater loudness adaptation was correlated with stronger activity within the ventral prefrontal cortex, which could be up-regulated to suppress the irrelevant or aberrant signals into the auditory cortex. The ability to detect these specific cortical patterns and differences across patients and stimuli demonstrates the potential for using PET to diagnose auditory function or dysfunction in implant patients, which in turn could guide the development of appropriate stimulation strategies for improving hearing rehabilitation. Beyond hearing restoration, our study also reveals a potential role of the frontal cortex in suppressing irrelevant or aberrant activity within the auditory cortex, and thus may be relevant for understanding and treating tinnitus. PMID:26046763

Simulated nuclear reactor fuel assembly

DOEpatents

Berta, V.T.

1993-04-06

An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor. The embedded conductor elements in each heater tube is split into two halves for a substantial portion of its length and provided with electrical isolation such that each half of the conductor is joined at one end and is not joined at the other end.

Simulated nuclear reactor fuel assembly

DOEpatents

Berta, Victor T.

1993-01-01

An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor. The embedded conductor elements in each heater tube is split into two halves for a substantial portion of its length and provided with electrical isolation such that each half of the conductor is joined at one end and is not joined at the other end.

The effect of a radial electric field on ripple-trapped ions observed by neutral particle fluxes

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

Heikkinen, J.A.; Herrmann, W.; Kurki-Suonio, T.

1997-10-01

The effect of a radial electric field on nonthermal ripple-trapped ions is investigated using toroidal Monte Carlo simulations for edge tokamak plasmas. The increase in the neutral particle flux from the ions trapped in local magnetic wells observed by the charge exchange (CX) detector at a low confinement to high confinement transition at ASDEX (Axially Symmetric Divertor Experiment). Upgrade tokamak [{ital Proceedings of the 20th European Conference on Controlled Fusion and Plasma Physics}, Lisbon (European Physical Society, Petit-Lancy, Switzerland, 1993), Vol. 17C, Part I, p. 267] is reproduced in the simulations by turning on a radial electric field near themore » plasma periphery. The poloidal and toroidal angles at which the CX detector signal is most sensitive to the radial electric field are determined. A fast response time of the signal in the range of 50{endash}100 {mu}s to the appearance of the electric field can be found in the simulations with a relatively large half-width of the negative electric field region. {copyright} {ital 1997 American Institute of Physics.}« less

Fuel Economy Improvement by Utilizing Thermoelectric Generator in Heavy-Duty Vehicle

NASA Astrophysics Data System (ADS)

Deng, Y. D.; Hu, T.; Su, C. Q.; Yuan, X. H.

2017-05-01

Recent advances in thermoelectric technology have made exhaust-based thermoelectric generators (TEGs) promising for recovery of waste heat. Utilization of exhaust-based TEGs in heavy-duty vehicles was studied in this work. Given that the generated power is limited, the alternator is still indispensable. To improve the fuel economy, the generated electricity must be integrated into the automotive electrical system and consumed by electrical loads. Therefore, two feasible ways of integrating the generated electricity into the automotive electrical system are discussed: one in which the original alternator works only under certain conditions, i.e., the "thermostat" strategy, and another in which a smaller alternator is adopted and works together with the TEG, i.e., the "cooperative work" strategy. The overall performance and efficiency are obtained through simulation analysis. The simulation results show that both methods can improve the fuel economy, but the former provides better results. Moreover, if the electrical loads can be properly modified, the fuel economy is further improved. These simulation results lay a solid foundation for application of TEGs in vehicles in the future.

Accurate Computation of Electric Field Enhancement Factors for Metallic Nanoparticles Using the Discrete Dipole Approximation

PubMed Central

2010-01-01

We model the response of nanoscale Ag prolate spheroids to an external uniform static electric field using simulations based on the discrete dipole approximation, in which the spheroid is represented as a collection of polarizable subunits. We compare the results of simulations that employ subunit polarizabilities derived from the Clausius–Mossotti relation with those of simulations that employ polarizabilities that include a local environmental correction for subunits near the spheroid’s surface [Rahmani et al. Opt Lett 27: 2118 (2002)]. The simulations that employ corrected polarizabilities give predictions in very good agreement with exact results obtained by solving Laplace’s equation. In contrast, simulations that employ uncorrected Clausius–Mossotti polarizabilities substantially underestimate the extent of the electric field “hot spot” near the spheroid’s sharp tip, and give predictions for the field enhancement factor near the tip that are 30 to 50% too small. PMID:20672062

Internal services simulation control in 220/110kV power transformer station Mintia

NASA Astrophysics Data System (ADS)

Ciulica, D.; Rob, R.

2018-01-01

The main objectives in developing the electric transport and distribution networks infrastructure are satisfying the electric energy demand, ensuring the continuity of supply to customers, minimizing electricity losses in the transmission and distribution networks of public interest. This paper presents simulations in functioning of the internal services system 400/230 V ac in the 220/110 kV power transformer station Mintia. Using simulations in Visual Basic, the following premises are taken into consideration. All the ac consumers of the 220/110 kV power transformer station Mintia will be supplied by three 400/230 V transformers for internal services which can mutual reserve. In case of damaging at one transformer, the others are able to assume the entire consumption using automatic release of reserves. The simulation program studies three variants in which the continuity of supply to customers are ensured. As well, by simulations, all the functioning situations are analyzed in detail.

The electrical properties of auditory hair cells in the frog amphibian papilla.

PubMed

Smotherman, M S; Narins, P M

1999-07-01

The amphibian papilla (AP) is the principal auditory organ of the frog. Anatomical and neurophysiological evidence suggests that this hearing organ utilizes both mechanical and electrical (hair cell-based) frequency tuning mechanisms, yet relatively little is known about the electrophysiology of AP hair cells. Using the whole-cell patch-clamp technique, we have investigated the electrical properties and ionic currents of isolated hair cells along the rostrocaudal axis of the AP. Electrical resonances were observed in the voltage response of hair cells harvested from the rostral and medial, but not caudal, regions of the AP. Two ionic currents, ICa and IK(Ca), were observed in every hair cell; however, their amplitudes varied substantially along the epithelium. Only rostral hair cells exhibited an inactivating potassium current (IA), whereas an inwardly rectifying potassium current (IK1) was identified only in caudal AP hair cells. Electrically tuned hair cells exhibited resonant frequencies from 50 to 375 Hz, which correlated well with hair cell position and the tonotopic organization of the papilla. Variations in the kinetics of the outward current contribute substantially to the determination of resonant frequency. ICa and IK(Ca) amplitudes increased with resonant frequency, reducing the membrane time constant with increasing resonant frequency. We conclude that a tonotopically organized hair cell substrate exists to support electrical tuning in the rostromedial region of the frog amphibian papilla and that the cellular mechanisms for frequency determination are very similar to those reported for another electrically tuned auditory organ, the turtle basilar papilla.

Theoretical transient analysis of a hearing aid feedback canceller with a saturation type nonlinearity in the direct path.

PubMed

Costa, Márcio Holsbach

2017-12-01

Feedback cancellation in a hearing aid is essential for achieving high maximum stable gain to compensate for the losses in severe to profound hearing impaired people. The performance of adaptive feedback cancellers has been studied by assuming that the feedback path can be modeled as a linear system. However, limited dynamic range, low-cost loudspeakers, and nonlinear power amplifiers may distort the hearing aid output signal. In this way, linear-based predictions of the canceller performance may lead to significant deviations from its actual behavior. This work presents a theoretical performance analysis of a Least Mean Square based shadow filter that is applied to set up the coefficients of a feedback canceller, which is subject to a static saturation type nonlinearity at the output of the direct path. Deterministic recursive equations are derived to predict the mean square feedback error and the mean coefficient vector evolution between updates of the feedback canceller. These models are defined as functions of the canceller parameters and input signal statistics. Comparisons with Monte Carlo simulations show the provided models are highly accurate under the considered assumptions. The developed models allow inferences about the potential impact of an overdriven loudspeaker over the transient performance of the direct method feedback canceller, serving as insightful tools for understanding the involved mechanisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preferred Compression Speed for Speech and Music and Its Relationship to Sensitivity to Temporal Fine Structure.

PubMed

Moore, Brian C J; Sęk, Aleksander

2016-09-07

Multichannel amplitude compression is widely used in hearing aids. The preferred compression speed varies across individuals. Moore (2008) suggested that reduced sensitivity to temporal fine structure (TFS) may be associated with preference for slow compression. This idea was tested using a simulated hearing aid. It was also assessed whether preferences for compression speed depend on the type of stimulus: speech or music. Twenty-two hearing-impaired subjects were tested, and the stimulated hearing aid was fitted individually using the CAM2A method. On each trial, a given segment of speech or music was presented twice. One segment was processed with fast compression and the other with slow compression, and the order was balanced across trials. The subject indicated which segment was preferred and by how much. On average, slow compression was preferred over fast compression, more so for music, but there were distinct individual differences, which were highly correlated for speech and music. Sensitivity to TFS was assessed using the difference limen for frequency at 2000 Hz and by two measures of sensitivity to interaural phase at low frequencies. The results for the difference limens for frequency, but not the measures of sensitivity to interaural phase, supported the suggestion that preference for compression speed is affected by sensitivity to TFS. © The Author(s) 2016.

Simulation of Light Collection for Neutron Electrical Dipole Moment measurement

NASA Astrophysics Data System (ADS)

Ji, Pan; nEDM Collaboration

2017-09-01

nEDM (Neutron Electrical Dipole moment) measurement addresses a critical topic in particle physics and Standard Model, that is CPT violation in neutron electrical dipole moment if detected in which the Time reversal violation is connected to the matter/antimatter imparity of the universe. The neutron electric dipole moment was first measured in 1950 by Smith, Purcell, and Ramsey at the Oak Ridge Reactor - the first intense neutron source. This measurement showed that the neutron was very nearly round (to better than one part in a million). The goal of the nEDM experiment is to further improve the precision of this measurement by another factor of 100. The signal from the experiment is detected by collecting the photons generated when neutron beams were captured by liquid helium 3. The Geant4 simulation project that I participate simulates the process of light collection to improve the design for higher capture efficiency. The simulated geometry includes light source, reflector, wavelength shifting fibers, wavelength shifting TPB and acrylic as in real experiment. The UV photons exiting from Helium go through two wavelength-shifting processes in TPB and fibers to be finally captured. Oak Ridge National Laboratory Neutron Electric Dipole Moment measurement project.

Sentence Recognition Prediction for Hearing-impaired Listeners in Stationary and Fluctuation Noise With FADE: Empowering the Attenuation and Distortion Concept by Plomp With a Quantitative Processing Model.

PubMed

Kollmeier, Birger; Schädler, Marc René; Warzybok, Anna; Meyer, Bernd T; Brand, Thomas

2016-09-07

To characterize the individual patient's hearing impairment as obtained with the matrix sentence recognition test, a simulation Framework for Auditory Discrimination Experiments (FADE) is extended here using the Attenuation and Distortion (A+D) approach by Plomp as a blueprint for setting the individual processing parameters. FADE has been shown to predict the outcome of both speech recognition tests and psychoacoustic experiments based on simulations using an automatic speech recognition system requiring only few assumptions. It builds on the closed-set matrix sentence recognition test which is advantageous for testing individual speech recognition in a way comparable across languages. Individual predictions of speech recognition thresholds in stationary and in fluctuating noise were derived using the audiogram and an estimate of the internal level uncertainty for modeling the individual Plomp curves fitted to the data with the Attenuation (A-) and Distortion (D-) parameters of the Plomp approach. The "typical" audiogram shapes from Bisgaard et al with or without a "typical" level uncertainty and the individual data were used for individual predictions. As a result, the individualization of the level uncertainty was found to be more important than the exact shape of the individual audiogram to accurately model the outcome of the German Matrix test in stationary or fluctuating noise for listeners with hearing impairment. The prediction accuracy of the individualized approach also outperforms the (modified) Speech Intelligibility Index approach which is based on the individual threshold data only. © The Author(s) 2016.

Early Bimodal Stimulation Benefits Language Acquisition for Children With Cochlear Implants.

PubMed

Moberly, Aaron C; Lowenstein, Joanna H; Nittrouer, Susan

2016-01-01

Adding a low-frequency acoustic signal to the cochlear implant (CI) signal (i.e., bimodal stimulation) for a period of time early in life improves language acquisition. Children must acquire sensitivity to the phonemic units of language to develop most language-related skills, including expressive vocabulary, working memory, and reading. Acquiring sensitivity to phonemic structure depends largely on having refined spectral (frequency) representations available in the signal, which does not happen with CIs alone. Combining the low-frequency acoustic signal available through hearing aids with the CI signal can enhance signal quality. A period with this bimodal stimulation has been shown to improve language skills in very young children. This study examined whether these benefits persist into childhood. Data were examined for 48 children with CIs implanted under age 3 years, participating in a longitudinal study. All children wore hearing aids before receiving a CI, but upon receiving a first CI, 24 children had at least 1 year of bimodal stimulation (Bimodal group), and 24 children had only electric stimulation subsequent to implantation (CI-only group). Measures of phonemic awareness were obtained at second and fourth grades, along with measures of expressive vocabulary, working memory, and reading. Children in the Bimodal group generally performed better on measures of phonemic awareness, and that advantage was reflected in other language measures. Having even a brief period of time early in life with combined electric-acoustic input provides benefits to language learning into childhood, likely because of the enhancement in spectral representations provided.

Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator

PubMed Central

Luo, Chuan; Omelchenko, Irina; Manson, Robert; Robbins, Carol; Oesterle, Elizabeth C.; Cao, Guo Zhong; Hume, Clifford R.

2015-01-01

Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800 µm by 800 µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24 kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays. PMID:26631107

Finite element simulation of thunderstorm electrodynamics in the proximity of the storm

NASA Technical Reports Server (NTRS)

Baginski, Michael Edward

1988-01-01

Observations of electric fields, Maxwell current density, and air conductivity over thunderstorms were presented. The measurements were obtained using electric field mils and conductivity probes installed on a U2 aircraft as the aircraft passed approximately directly over an active thunderstorm at an altitude of 18 to 20 km. Accurate electrical observations of this type are rare and provide important information to those involved in numerically modeling a thunderstorm. A preliminary set of computer simulations based on this data were conducted and are described. The simulations show good agreement with measurements and are used to infer the thundercloud's charging current and amount of charge exchanged per flash.

Physical and Electronic Isolation of Carbon Nanotube Conductors

NASA Technical Reports Server (NTRS)

OKeeffe, James; Biegel, Bryan (Technical Monitor)

2001-01-01

Multi-walled nanotubes are proposed as a method to electrically and physically isolate nanoscale conductors from their surroundings. We use tight binding (TB) and density functional theory (DFT) to simulate the effects of an external electric field on multi-wall nanotubes. Two categories of multi-wall nanotube are investigated, those with metallic and semiconducting outer shells. In the metallic case, simulations show that the outer wall effectively screens the inner core from an applied electric field. This offers the ability to reduce crosstalk between nanotube conductors. A semiconducting outer shell is found not to perturb an electric field incident on the inner core, thereby providing physical isolation while allowing the tube to remain electrically coupled to its surroundings.

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

PubMed Central

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

2012-01-01

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

Algorithms and architecture for multiprocessor based circuit simulation

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

Deutsch, J.T.

Accurate electrical simulation is critical to the design of high performance integrated circuits. Logic simulators can verify function and give first-order timing information. Switch level simulators are more effective at dealing with charge sharing than standard logic simulators, but cannot provide accurate timing information or discover DC problems. Delay estimation techniques and cell level simulation can be used in constrained design methods, but must be tuned for each application, and circuit simulation must still be used to generate the cell models. None of these methods has the guaranteed accuracy that many circuit designers desire, and none can provide detailed waveformmore » information. Detailed electrical-level simulation can predict circuit performance if devices and parasitics are modeled accurately. However, the computational requirements of conventional circuit simulators make it impractical to simulate current large circuits. In this dissertation, the implementation of Iterated Timing Analysis (ITA), a relaxation-based technique for accurate circuit simulation, on a special-purpose multiprocessor is presented. The ITA method is an SOR-Newton, relaxation-based method which uses event-driven analysis and selective trace to exploit the temporal sparsity of the electrical network. Because event-driven selective trace techniques are employed, this algorithm lends itself to implementation on a data-driven computer.« less

High-Fidelity Simulations of Electrically-Charged Atomizing Diesel-Type Jets

NASA Astrophysics Data System (ADS)

Gaillard, Benoit; Owkes, Mark; van Poppel, Bret

2015-11-01

Combustion of liquid fuels accounts for over a third of the energy usage today. Improving efficiency of combustion systems is critical to meet the energy needs while limiting environmental impacts. Additionally, a shift away from traditional fossil fuels to bio-derived alternatives requires fuel injection systems that can atomize fuels with a wide range of properties. In this work, the potential benefits of electrically-charged atomization is investigated using numerical simulations. Particularly, the electrostatic forces on the hydrodynamic jet are quantified and the impact of the forces is analyzed by comparing simulations of Diesel-type jets at realistic flow conditions. The simulations are performed using a state-of-the-art numerical framework that globally conserves mass, momentum, and the electric charge density even at the gas-liquid interface where discontinuities exist.

Simulation study on heat conduction of a nanoscale phase-change random access memory cell.

PubMed

Kim, Junho; Song, Ki-Bong

2006-11-01

We have investigated heat transfer characteristics of a nano-scale phase-change random access memory (PRAM) cell using finite element method (FEM) simulation. Our PRAM cell is based on ternary chalcogenide alloy, Ge2Sb2Te5 (GST), which is used as a recording layer. For contact area of 100 x 100 nm2, simulations of crystallization and amorphization processes were carried out. Physical quantities such as electric conductivity, thermal conductivity, and specific heat were treated as temperature-dependent parameters. Through many simulations, it is concluded that one can reduce set current by decreasing both electric conductivities of amorphous GST and crystalline GST, and in addition to these conditions by decreasing electric conductivity of molten GST one can also reduce reset current significantly.

Automatic detection of electric power troubles (AI application)

NASA Technical Reports Server (NTRS)

Wang, Caroline; Zeanah, Hugh; Anderson, Audie; Patrick, Clint

1987-01-01

The design goals for the Automatic Detection of Electric Power Troubles (ADEPT) were to enhance Fault Diagnosis Techniques in a very efficient way. ADEPT system was designed in two modes of operation: (1) Real time fault isolation, and (2) a local simulator which simulates the models theoretically.

Modeling Spoken Word Recognition Performance by Pediatric Cochlear Implant Users using Feature Identification

PubMed Central

Frisch, Stefan A.; Pisoni, David B.

2012-01-01

Objective Computational simulations were carried out to evaluate the appropriateness of several psycholinguistic theories of spoken word recognition for children who use cochlear implants. These models also investigate the interrelations of commonly used measures of closed-set and open-set tests of speech perception. Design A software simulation of phoneme recognition performance was developed that uses feature identification scores as input. Two simulations of lexical access were developed. In one, early phoneme decisions are used in a lexical search to find the best matching candidate. In the second, phoneme decisions are made only when lexical access occurs. Simulated phoneme and word identification performance was then applied to behavioral data from the Phonetically Balanced Kindergarten test and Lexical Neighborhood Test of open-set word recognition. Simulations of performance were evaluated for children with prelingual sensorineural hearing loss who use cochlear implants with the MPEAK or SPEAK coding strategies. Results Open-set word recognition performance can be successfully predicted using feature identification scores. In addition, we observed no qualitative differences in performance between children using MPEAK and SPEAK, suggesting that both groups of children process spoken words similarly despite differences in input. Word recognition ability was best predicted in the model in which phoneme decisions were delayed until lexical access. Conclusions Closed-set feature identification and open-set word recognition focus on different, but related, levels of language processing. Additional insight for clinical intervention may be achieved by collecting both types of data. The most successful model of performance is consistent with current psycholinguistic theories of spoken word recognition. Thus it appears that the cognitive process of spoken word recognition is fundamentally the same for pediatric cochlear implant users and children and adults with normal hearing. PMID:11132784

Crash simulation of UNS electric vehicle under frontal front impact

NASA Astrophysics Data System (ADS)

Susilo, D. D.; Lukamana, N. I.; Budiana, E. P.; Tjahjana, D. D. D. P.

2016-03-01

Sebelas Maret University has been developing an Electric Vehicle namely SmarT-EV UNS. The main structure of the car are chasis and body. The chasis is made from steel and the body is made from fiberglass composite. To ensure the safety of the car, both static and dynamic tests were carried out to these structures, including their materials, like: tensile test, bending test, and impact test. Another test needed by this vehicle is crashworthiness test. To perform the test, it is needed complex equipments and it is quite expensive. Another way to obtain vehicle crashworthiness behaviour is by simulate it. The purpose of this study was to simulate the response of the Smart-EV UNS electric vehicle main structure when crashing rigid barrier from the front. The crash simulation was done in according to the NHTSA (National Highway Traffic Safety Administration) within the speed of the vehicle of 35 mph. The UNS Electric Vehicle was modelled using SolidWorks software, and the simulation process was done by finite element method using ANSYS software. The simulation result showed that the most internal impact energy was absorbed by chassis part. It absorbed 76.2% of impact energy, then the base absorbed 11.3 %, while the front body absorbed 2.5 %, and the rest was absorbed by fender, hood, and other parts.

Simulation of a manual electric-arc welding in a working gas pipeline. 2. Numerical investigation of the temperature-stress distribution in the wall of a gas pipe

NASA Astrophysics Data System (ADS)

Baikov, V. I.; Gishkelyuk, I. A.; Rus', A. M.; Sidorovich, T. V.; Tonkonogov, B. A.

2010-11-01

A numerical simulation of the action of the current experienced by an electric arc and the rate of gas flow in a pipe of a cross-country gas pipeline on the depth of penetration of the electric arc into the wall of this pipe and on the current and residual stresses arising in the pipe material in the process of electric-arc welding of nonthrough cavity-like defects in it has been carried out for gas pipes with walls of different thickness.

Particle-in-Cell Simulations of the Twisted Magnetospheres of Magnetars. I.

NASA Astrophysics Data System (ADS)

Chen, Alexander Y.; Beloborodov, Andrei M.

2017-08-01

The magnetospheres of magnetars are believed to be filled with electron-positron plasma generated by electric discharge. We present a first numerical experiment demonstrating this process in an axisymmetric magnetosphere with a simple threshold prescription for pair creation, which is applicable to the inner magnetosphere with an ultrastrong field. The {e}+/- discharge occurs in response to the twisting of the closed magnetic field lines by a shear deformation of the magnetar surface, which launches electric currents into the magnetosphere. The simulation shows the formation of an electric “gap” with an unscreened electric field ({\\boldsymbol{E}}\\cdot {\\boldsymbol{B}}\

Development of electrical test procedures for qualification of spacecraft against EID. Volume 1: The CAN test and other relevant data

NASA Technical Reports Server (NTRS)

Wilkenfeld, J. M.; Judge, R. J. R.; Harlacher, B. L.

1982-01-01

A combined experimental and analytical program to develop system electrical test procedures for the qualification of spacecraft against damage produced by space-electron-induced discharges (EID) occurring on spacecraft dielectric outer surfaces is described. The data on the response of a simple satellite model, called CAN, to electron-induced discharges is presented. The experimental results were compared to predicted behavior and to the response of the CAN to electrical injection techniques simulating blowoff and arc discharges. Also included is a review of significant results from other ground tests and the P78-2 program to form a data base from which is specified those test procedures which optimally simulate the response of spacecraft to EID. The electrical and electron spraying test data were evaluated to provide a first-cut determination of the best methods for performance of electrical excitation qualification tests from the point of view of simulation fidelity.

The Use of Simulation in Audiology Education to Improve Students' Professional Competency

ERIC Educational Resources Information Center

Alanazi, Ahmad A.

2017-01-01

Thousands of children are diagnosed with hearing loss every year in the United States (U.S.) and worldwide. The advanced technology and the growing body of research support the early identification, diagnosis, and intervention of these children, so training audiology students and other healthcare students (e.g., nursing students) is important.…

Binaural unmasking with multiple adjacent masking electrodes in bilateral cochlear implant users

PubMed Central

Lu, Thomas; Litovsky, Ruth; Zeng, Fan-Gang

2011-01-01

Bilateral cochlear implant (BiCI) users gain an advantage in noisy situations from a second implant, but their bilateral performance falls short of normal hearing listeners. Channel interactions due to overlapping electrical fields between electrodes can impair speech perception, but its role in limiting binaural hearing performance has not been well characterized. To address the issue, binaural masking level differences (BMLD) for a 125 Hz tone in narrowband noise were measured using a pair of pitch-matched electrodes while simultaneously presenting the same masking noise to adjacent electrodes, representing a more realistic stimulation condition compared to prior studies that used only a single electrode pair. For five subjects, BMLDs averaged 8.9 ± 1.0 dB (mean ± s.e.) in single electrode pairs but dropped to 2.1 ± 0.4 dB when presenting noise on adjacent masking electrodes, demonstrating a negative impact of the additional maskers. Removing the masking noise from only the pitch-matched electrode pair not only lowered thresholds but also resulted in smaller BMLDs. The degree of channel interaction estimated from auditory nerve evoked potentials in three subjects was significantly and negatively correlated with BMLD. The data suggest that if the amount of channel interactions can be reduced, BiCI users may experience some performance improvements related to binaural hearing. PMID:21682415

Energy Saving in DC Electric Railways by Battery Substation

NASA Astrophysics Data System (ADS)

Sugimoto, Takeshi

New rolling vehicles used in dc electric railways are of the regenerative type. At less busy time a part of regenerative power is not used for powering vehicles, and canceled by changed air brake. Recently, significant attention has been paid to the development of secondary batteries for hybrid and electric motorcars. The use of this battery enables reduction in electric power consumption. Because we can charge excess regenerative power and use for powering vehicles after. Before the fact we compared the actual and simulated effective coefficient of regenerative energy, we confirmed the suitability of the simulation model. In this simulation, we studied the energy-saving effect of the battery substations and determined the battery capacity at which maximum power saving is achieved. We found that the power consumption could be reduced remarkably by using a 15-20kWh battery substation.

Composition and Manufacturing Effects on Electrical Conductivity of Li/FeS 2 Thermal Battery Cathodes

DOE PAGES

Reinholz, Emilee L.; Roberts, Scott A.; Apblett, Christopher A.; ...

2016-06-11

The electrical conductivity is key to the performance of thermal battery cathodes. In this work we present the effects of manufacturing and processing conditions on the electrical conductivity of Li/FeS2 thermal battery cathodes. Finite element simulations were used to compute the conductivity of three-dimensional microcomputed tomography cathode microstructures and compare results to experimental impedance spectroscopy measurements. A regression analysis reveals a predictive relationship between composition, processing conditions, and electrical conductivity; a trend which is largely erased after thermally-induced deformation. Moreover, the trend applies to both experimental and simulation results, although is not as apparent in simulations. This research is amore » step toward a more fundamental understanding of the effects of processing and composition on thermal battery component microstructure, properties, and performance.« less

Development of hybrid electric vehicle powertrain test system based on virtue instrument

NASA Astrophysics Data System (ADS)

Xu, Yanmin; Guo, Konghui; Chen, Liming

2017-05-01

Hybrid powertrain has become the standard configuration of some automobile models. The test system of hybrid vehicle powertrain was developed based on virtual instrument, using electric dynamometer to simulate the work of engines, to test the motor and control unit of the powertrain. The test conditions include starting, acceleration, and deceleration. The results show that the test system can simulate the working conditions of the hybrid electric vehicle powertrain under various conditions.

Anatomically realistic multiscale models of normal and abnormal gastrointestinal electrical activity

PubMed Central

Cheng, Leo K; Komuro, Rie; Austin, Travis M; Buist, Martin L; Pullan, Andrew J

2007-01-01

One of the major aims of the International Union of Physiological Sciences (IUPS) Physiome Project is to develop multiscale mathematical and computer models that can be used to help understand human health. We present here a small facet of this broad plan that applies to the gastrointestinal system. Specifically, we present an anatomically and physiologically based modelling framework that is capable of simulating normal and pathological electrical activity within the stomach and small intestine. The continuum models used within this framework have been created using anatomical information derived from common medical imaging modalities and data from the Visible Human Project. These models explicitly incorporate the various smooth muscle layers and networks of interstitial cells of Cajal (ICC) that are known to exist within the walls of the stomach and small bowel. Electrical activity within individual ICCs and smooth muscle cells is simulated using a previously published simplified representation of the cell level electrical activity. This simulated cell level activity is incorporated into a bidomain representation of the tissue, allowing electrical activity of the entire stomach or intestine to be simulated in the anatomically derived models. This electrical modelling framework successfully replicates many of the qualitative features of the slow wave activity within the stomach and intestine and has also been used to investigate activity associated with functional uncoupling of the stomach. PMID:17457969