Auditory Midbrain Implant: Research and Development Towards a Second Clinical Trial.
Abstract The cochlear implant is considered one of the most successful neural prostheses to date, which was made possible by visionaries who continued to develop the cochlear implant through multiple technological and clinical challenges. However, patients without a functional auditory nerve or implantable cochlea cannot benefit from a cochlear implant. The focus of the paper is to review the development and translation of a new type of central auditory prosthesis for this group of patients, which is known as the auditory midbrain implant (AMI) and is designed for electrical stimulation within the inferior collicu...
Source: Hearing Research - January 19, 2015 Category: Audiology Authors: Lim HH, Lenarz T Tags: Hear Res Source Type: research
Auditory deficits of Kcna1 deletion are similar to those of a monaural hearing impairment.
Abstract Kv1.1 subunits of low voltage-activated (Kv) potassium channels are encoded by the Kcna1 gene and crucially determine the synaptic integration window to control the number and temporal precision of action potentials in the auditory brainstem of mammals and birds. Prior electrophysiological studies showed that auditory signaling is compromised in monaural as well as in binaural neurons of the auditory brainstem in Kv1.1 knockout mice (Kcna1(-/-)). Here we examine the behavioral effects of Kcna1 deletion on sensory tasks dependent on either binaural processing (detecting the movement of a sound source acros...
Source: Hearing Research - January 17, 2015 Category: Audiology Authors: Karcz A, Allen PD, Walton J, Ison JR, Kopp-Scheinpflug C Tags: Hear Res Source Type: research
Considering optogenetic stimulation for cochlear implants.
This article is part of a Special Issue entitled . PMID: 25601298 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - January 16, 2015 Category: Audiology Authors: Jeschke M, Moser T Tags: Hear Res Source Type: research
Superior Temporal Resolution of Chronos versus Channelrhodopsin-2 in an Optogenetic Model of the Auditory Brainstem Implant.
Abstract Contemporary auditory brainstem implant (ABI) performance is limited by reliance on electrical neurostimulation with its accompanying channel cross talk and current spread to non-auditory neurons. A new generation ABI based on optogenetic-technology may ameliorate limitations fundamental to electrical stimulation. The most widely studied opsin is channelrhodopsin-2 (ChR2); however, its relatively slow kinetic properties may prevent the encoding of auditory information at high stimulation rates. In the present study, we compare to ChR2 the temporal resolution of light-evoked responses of a recently develop...
Source: Hearing Research - January 15, 2015 Category: Audiology Authors: Edward Hight A, Kozin ED, Darrow K, Lehmann A, Boyden E, Brown MC, Lee DJ Tags: Hear Res Source Type: research
Recovery characteristics of the electrically stimulated auditory nerve in deafened guinea pigs: Relation to neuronal status.
Abstract Successful cochlear implant performance requires adequate responsiveness of the auditory nerve to prolonged pulsatile electrical stimulation. Degeneration of the auditory nerve as a result of severe hair cell loss could considerably compromise this ability. The main objective of this study was to characterize the recovery of the electrically stimulated auditory nerve, as well as to evaluate possible changes caused by deafness-induced degeneration. To this end we studied temporal responsiveness of the auditory nerve in a guinea pig model of sensorineural hearing loss. Using masker-probe and pulse train par...
Source: Hearing Research - January 9, 2015 Category: Audiology Authors: Ramekers D, Versnel H, Strahl SB, Klis SF, Grolman W Tags: Hear Res Source Type: research
Comparison of the sensitivity of prepulse inhibition of the startle reflex and operant conditioning in an auditory intensity difference limen paradigm.
Abstract Reward-based operant conditioning (OC) procedures and reflex-based prepulse inhibition (PPI) procedures are used in mouse psychoacoustics. Therefore it is important to know whether both procedures provide comparable results for perceptual measurements. Here we evaluate the sensitivity of the C57BL/6N mouse in both procedures by testing the same individuals in the same Intensity Difference Limen (IDL(1)) task. Level increments of a 10 kHz tone were presented in a train of 10 kHz reference tones. Objective analysis based on signal-detection theory was applied to compare the results of OC and PPI p...
Source: Hearing Research - January 8, 2015 Category: Audiology Authors: Behrens D, Klump GM Tags: Hear Res Source Type: research
Perineuronal nets in the auditory system.
i M Abstract Perineuronal nets (PNs) are a unique and complex meshwork of specific extracellular matrix molecules that ensheath a subset of neurons in many regions of the central nervous system (CNS). PNs appear late in development and are supposed to restrict synaptic plasticity and to stabilize functional neuronal connections. PNs were further hypothesized to create a charged milieu around the neurons and thus, might directly modulate synaptic activity. Although PNs were first described more than 120 years ago, their exact functions still remain elusive. The purpose of the present review is to propose the nuclei...
Source: Hearing Research - January 8, 2015 Category: Audiology Authors: Sonntag M, Blosa M, Schmidt S, Rübsamen R, Morawski M Tags: Hear Res Source Type: research
Nanogrooved Surface-Patterns induce cellular organization and axonal outgrowth in neuron-like PC12-Cells.
In conclusion, surface nanopatterns have the potential to be utilized as an electrode modification for a stronger separation of cells, and can be used to direct cells towards the electrode contacts of cochlear implants. PMID: 25576787 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - January 7, 2015 Category: Audiology Authors: Klymov A, Rodrigues Neves CT, Riet JT, Agterberg MJ, Mylanus EA, Snik AF, Jansen JA, Walboomers XF Tags: Hear Res Source Type: research
Morphological and morphometric characterization of direct transdifferentiation of support cells into hair cells in ototoxin-exposed postnatal utricular explants.
Abstract We have studied aminoglycoside-induced vestibular hair-cell renewal using long-term culture of utricular macula explants from 4-day-old rats. Explanted utricles were exposed to 1 mM of gentamicin for 48 h, during 2(nd) and 3(rd) days in vitro (DIV), and then recovering in unsupplemented medium. Utricles were harvested at specified time points from the 2(nd) through the 28(th) DIV. The cellular events that occurred within hair cell epithelia during the culture period were documented from serial sectioned specimens. Vestibular hair cells (HCs) and supporting cells (SCs) were systematically counted using lig...
Source: Hearing Research - January 7, 2015 Category: Audiology Authors: Werner M, Van De Water TR, Hammarsten P, Arnoldsson G, Berggren D Tags: Hear Res Source Type: research
Usher syndrome: An effective sequencing approach to establish a genetic and clinical diagnosis.
Abstract Usher syndrome is an autosomal recessive disorder characterized by retinitis pigmentosa, sensorineural hearing loss and, in some cases, vestibular dysfunction. The disorder is clinically and genetically heterogeneous and, to date, mutations in 11 genes have been described. This finding makes difficult to get a precise molecular diagnosis and offer patients accurate genetic counselling. To overcome this problem and to increase our knowledge of the molecular basis of Usher syndrome, we designed a targeted resequencing custom panel. In a first validation step a series of 16 Italian patients with known molecu...
Source: Hearing Research - January 6, 2015 Category: Audiology Authors: Lenarduzzi S, Vozzi D, Morgan A, Rubinato E, D'Eustacchio A, Osland TM, Rossi C, Graziano C, Castorina P, Ambrosetti U, Morgutti M, Girotto G Tags: Hear Res Source Type: research
Cochlear implant users move in time to the beat of drum music.
Abstract Cochlear implant users show a profile of residual, yet poorly understood, musical abilities. An ability that has received little to no attention in this population is entrainment to a musical beat. We show for the first time that a heterogeneous group of cochlear implant users is able to find the beat and move their bodies in time to Latin Merengue music, especially when the music is presented in unpitched drum tones. These findings not only reveal a hidden capacity for feeling musical rhythm through the body in the deaf and hearing impaired population, but illuminate promising avenues for designing early...
Source: Hearing Research - January 6, 2015 Category: Audiology Authors: Phillips-Silver J, Toiviainen P, Gosselin N, Turgeon C, Lepore F, Peretz I Tags: Hear Res Source Type: research
Early UCSF Contributions to the Development of Multiple-Channel Cochlear Implants.
Abstract The early contributions of the UCSF cochlear implant (CI) research team to the development of multiple-channel cochlear implants from about 1971 through the mid-1980s are briefly summarized. Scientists at UCSF conducted fundamental studies related to device safety, the control of patterned electrical stimulation, and the designs of intracochlear electrode arrays, coders, and implanted multiple-channel electrode drivers. They conducted many original studies documenting parameters of hearing with cochlear implants relevant to next-generation CI designs. On these bases, the UCSF team constructed early models...
Source: Hearing Research - January 2, 2015 Category: Audiology Authors: Merzenich MM Tags: Hear Res Source Type: research
Unilateral spectral and temporal compression reduces binaural fusion for normal hearing listeners with cochlear implant simulations.
Abstract Patients with single sided deafness have recently begun receiving cochlear implants in their deaf ear. These patients gain a significant benefit from having a cochlear implant. However, despite this benefit, they are considerably slower to develop binaural abilities such as summation compared to bilateral cochlear implant patients. This suggests that these patients have difficulty fusing electric and acoustic signals. Although this may reflect inherent differences between electric and acoustic stimulation, it may also reflect properties of the processor and fitting system, which result in spectral and tem...
Source: Hearing Research - December 27, 2014 Category: Audiology Authors: Aronoff JM, Shayman C, Prasad A, Suneel D, Stelmach J Tags: Hear Res Source Type: research
Eye color as a risk factor for acquired sensorineural hearing loss: A review.
CONCLUSIONS: Eye color does not appear to play a role in hearing loss in non-exposed individuals or presbycusis. It is possible that dark-eyed individuals, with greater inner ear melanin content, are better protected against noise-induced hearing loss. Evidence suggests that melanin can be protective against radiation-induced sensorineural hearing loss, but may predispose individuals to cisplatin ototoxicity. Future studies are required to support these conclusions. PMID: 25529530 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - December 19, 2014 Category: Audiology Authors: Mujica-Mota MA, Schermbrucker J, Daniel SJ Tags: Hear Res Source Type: research
A behavioral audiogram of the red fox (Vulpes vulpes).
Abstract We determined the absolute hearing sensitivity of the red fox (Vulpes vulpes) using an adapted standard psychoacoustic procedure. The animals were tested in a reward-based go/no-go procedure in a semi-anechoic chamber. At 60 dB sound pressure level (SPL) (re 20 μPa) red foxes perceive pure tones between 51 Hz and 48 kHz, spanning 9.84 octaves with a single peak sensitivity of -15 dB at 4 kHz. The red foxes' high-frequency cutoff is comparable to that of the domestic dog while the low-frequency cutoff is comparable to that of the domestic cat and the absolute sensitivi...
Source: Hearing Research - December 18, 2014 Category: Audiology Authors: Malkemper EP, Topinka V, Burda H Tags: Hear Res Source Type: research
Current focusing in cochlear implants: An analysis of neural recruitment in a computational model.
Abstract Several multipolar current focusing strategies are examined in a computational model of the implanted human cochlea. The model includes a realistic spatial distribution of cell bodies of the auditory neurons throughout Rosenthal's canal. Simulations are performed of monopolar, (partial) tripolar and phased array stimulation. Excitation patterns, estimated thresholds, electrical dynamic range, excitation density and neural recruitment curves are determined and compared. The main findings are: (I) current focusing requires electrical field interaction to induce spatially restricted excitation patterns. For ...
Source: Hearing Research - December 17, 2014 Category: Audiology Authors: Kalkman RK, Briaire JJ, Frijns JH Tags: Hear Res Source Type: research
Inner ear contribution to bone conduction hearing in the human.
Abstract Bone conduction (BC) hearing relies on sound vibration transmission in the skull bone. Several clinical findings indicate that in the human, the skull vibration of the inner ear dominates the response for BC sound. Two phenomena transform the vibrations of the skull surrounding the inner ear to an excitation of the basilar membrane, (1) inertia of the inner ear fluid and (2) compression and expansion of the inner ear space. The relative importance of these two contributors were investigated using an impedance lumped element model. By dividing the motion of the inner ear boundary in common and differential...
Source: Hearing Research - December 17, 2014 Category: Audiology Authors: Stenfelt S Tags: Hear Res Source Type: research
The early days of the multi channel cochlear implant: Efforts and achievement in France.
This article is part of a Special Issue entitled . PMID: 25499127 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - December 10, 2014 Category: Audiology Authors: Chouard CH Tags: Hear Res Source Type: research
Sensitivity of envelope following responses to vowel polarity.
Abstract Envelope following responses (EFRs) elicited by stimuli of opposite polarities are often averaged due to their insensitivity to polarity when elicited by amplitude modulated tones. A recent report illustrates that individuals exhibit varying degrees of polarity-sensitive differences in EFR amplitude when elicited by vowel stimuli (Aiken and Purcell, 2013). The aims of the current study were to evaluate the incidence and degree of polarity-sensitive differences in EFRs recorded in a large group of individuals, and to examine potential factors influencing the polarity-sensitive nature of EFRs. In Experiment...
Source: Hearing Research - December 8, 2014 Category: Audiology Authors: Easwar V, Beamish L, Aiken S, Choi JM, Scollie S, Purcell D Tags: Hear Res Source Type: research
Getting a decent (but sparse) signal to the brain for users of cochlear implants.
Abstract The challenge in getting a decent signal to the brain for users of cochlear implants (CIs) is described. A breakthrough occurred in 1989 that later enabled most users to understand conversational speech with their restored hearing alone. Subsequent developments included stimulation in addition to that provided with a unilateral CI, either with electrical stimulation on both sides or with acoustic stimulation in combination with a unilateral CI, the latter for persons with residual hearing at low frequencies in either or both ears. Both types of adjunctive stimulation produced further improvements in perfo...
Source: Hearing Research - December 8, 2014 Category: Audiology Authors: Wilson BS Tags: Hear Res Source Type: research
Familial hemiplegic migraine type-1 mutated cav2.1 calcium channels alter inhibitory and excitatory synaptic transmission in the lateral superior olive of mice.
Abstract CaV2.1 Ca(2+) channels play a key role in triggering neurotransmitter release and mediating synaptic transmission. Familial hemiplegic migraine type-1 (FHM-1) is caused by missense mutations in the CACNA1A gene that encodes the α1A pore-forming subunit of CaV2.1 Ca(2+) channels. We used knock-in (KI) transgenic mice harbouring the pathogenic FHM-1 mutation R192Q to study inhibitory and excitatory neurotransmission in the principle neurons of the lateral superior olive (LSO) in the auditory brainstem. We tested if the R192Q FHM-1 mutation differentially affects excitatory and inhibitory synaptic tran...
Source: Hearing Research - December 4, 2014 Category: Audiology Authors: Inchauspe CG, Pilati N, Di Guilmi MN, Urbano FJ, Ferrari MD, van den Maagdenberg AM, Forsythe ID, Uchitel OD Tags: Hear Res Source Type: research
Biological correlates of tinnitus-related distress: An exploratory study.
Abstract During the process of tinnitus diagnostics, various psychometric instruments are used to measure tinnitus-related distress. The aim of present work was to explore whether candidates for biological correlates of the tinnitus-related distress could be found in peripheral blood of patients and if so, whether there was association between them and psychometric scores that reflect tinnitus-related distress. The concentrations of interleukin-1β (IL1β), interleukin-6 (IL6), tumor necrosis factor-α (TNFα) and a brain-derived neutrotrophic factor (BDNF) were measured in serum of 30 patients d...
Source: Hearing Research - December 1, 2014 Category: Audiology Authors: Szczepek AJ, Haupt H, Klapp BF, Olze H, Mazurek B Tags: Hear Res Source Type: research
Attentional modulation of medial olivocochlear inhibition: Evidence for immaturity in children.
Abstract Efferent feedback shapes afferent auditory processing. Auditory attention has been shown to modulate medial olivocochlear (MOC) efferent activity in human adults. Since auditory attention continues to develop throughout childhood, the present study explored whether attentional control of medial-efferent inhibition in 5-10 year-old children is adult-like. MOC inhibition was measured in adults (n = 14) and children (n = 12) during no-task (contralateral broadband noise), passive (contralateral noise with tone-pips) and active listening conditions (attended tone-pips embedded in contralat...
Source: Hearing Research - December 1, 2014 Category: Audiology Authors: Mishra SK Tags: Hear Res Source Type: research
Turtle utricle dynamic behavior using a combined anatomically accurate model and experimentally measured hair bundle stiffness.
Abstract Anatomically correct turtle utricle geometry was incorporated into two finite element models. The geometrically accurate model included appropriately shaped macular surface and otoconial layer, compact gel and column filament (or shear) layer thicknesses and thickness distributions. The first model included a shear layer where the effects of hair bundle stiffness was included as part of the shear layer modulus. This solid model's undamped natural frequency was matched to an experimentally measured value. This frequency match established a realistic value of the effective shear layer Young's modulus of 16&...
Source: Hearing Research - December 1, 2014 Category: Audiology Authors: Davis JL, Grant JW Tags: Hear Res Source Type: research
Speech perception with interaction-compensated simultaneous stimulation and long pulse durations in cochlear implant users.
Abstract Early multi-channel designs in the history of cochlear implant development were based on a vocoder-type processing of frequency channels and presented bands of compressed analog stimulus waveforms simultaneously on multiple tonotopically arranged electrodes. The realization that the direct summation of electrical fields as a result of simultaneous electrode stimulation exacerbates interactions among the stimulation channels and limits cochlear implant outcome led to the breakthrough in the development of cochlear implants, the continuous interleaved (CIS) sampling coding strategy. By interleaving stimulat...
Source: Hearing Research - November 29, 2014 Category: Audiology Authors: Schatzer R, Koroleva I, Griessner A, Levin S, Kusovkov V, Yanov Y, Zierhofer C Tags: Hear Res Source Type: research
Localization Training Results in Individuals with Unilateral Severe to Profound Hearing Loss.
Abstract Adults with unilateral hearing loss often demonstrate decreased sound localization ability and report that situations requiring spatial hearing are especially challenging. Few studies have evaluated localization abilities combined with training in this population. The present pilot study examined whether localization of two sound types would improve after training, and explored the relation between localization ability or training benefit and demographic factors. Eleven participants with unilateral severe to profound hearing loss attended five training sessions; localization cues gradually decreased acros...
Source: Hearing Research - November 29, 2014 Category: Audiology Authors: Firszt JB, Reeder RM, Dwyer NY, Burton H, Holden LK Tags: Hear Res Source Type: research
Auditory Implant Research at the House Ear Institute 1989-2013.
This article is part of a Special Issue entitled . PMID: 25449009 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 17, 2014 Category: Audiology Authors: Shannon RV Tags: Hear Res Source Type: research
Simulating the dual-peak excitation pattern produced by bipolar stimulation of a cochlear implant: Effects on speech intelligibility.
Abstract Several electrophysiological and psychophysical studies have shown that the spatial excitation pattern produced by bipolar stimulation of a cochlear implant (CI) can have a dual-peak shape. The perceptual effects of this dual-peak shape were investigated using noise-vocoded CI simulations in which synthesis filters were designed to simulate the spread of neural activity produced by various electrode configurations, as predicted by a simple cochlear model. Experiments 1 and 2 tested speech recognition in the presence of a concurrent speech masker for various sets of single-peak and dual-peak synthesis filt...
Source: Hearing Research - November 15, 2014 Category: Audiology Authors: Mesnildrey Q, Macherey O Tags: Hear Res Source Type: research
Further tests of the local nonlinear interaction-based mechanism for simultaneous suppression of tone burst-evoked otoacoustic emissions.
Abstract Tone burst-evoked otoacoustic emission (TBOAE) components measured in response to a 1 kHz tone burst (TB1) are suppressed by the simultaneous presence of an additional tone burst (TB2). This "simultaneous suppression of TBOAEs" has been explained in terms of a mechanism based on local nonlinear interactions between the basilar membrane (BM) travelling waves caused by TB1 and TB2. A test of this local nonlinear interaction (LNI)-based mechanism, as a function of the frequency separation (Δf, expressed in kHz) between TB1 and TB2, has previously been reported by Killan et al. (2012...
Source: Hearing Research - November 7, 2014 Category: Audiology Authors: Killan EC, Lutman ME, Thyer NJ Tags: Hear Res Source Type: research
Neural correlates of perceptual grouping effects in the processing of sound omission by musicians and nonmusicians.
Abstract Perceptual grouping is the process of organizing sounds into perceptually meaningful elements. Psychological studies have found that tones presented as a regular frequency or temporal pattern are grouped according to gestalt principles, such as similarity, proximity, and good continuity. Predictive coding theory suggests that this process helps create an internal model for the prediction of sounds in a tone sequence and that an omission-related brain response reflects the violation of this prediction. However, it remains unclear which brain areas are related to this process, especially in paying attention...
Source: Hearing Research - November 7, 2014 Category: Audiology Authors: Ono K, Altmann CF, Matsuhashi M, Mima T, Fukuyama H Tags: Hear Res Source Type: research
Gradual adaptation to auditory frequency mismatch.
This article is part of a Special Issue entitled . PMID: 25445816 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 6, 2014 Category: Audiology Authors: Svirsky MA, Talavage TM, Sinha S, Neuburger H, Azadpour M Tags: Hear Res Source Type: research
Assessment of responses to cochlear implant stimulation at different levels of the auditory pathway.
This article is part of a Special Issue entitled . PMID: 25445817 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - November 4, 2014 Category: Audiology Authors: Abbas PJ, Brown CJ Tags: Hear Res Source Type: research
Deep electrode insertion and sound coding in cochlear implants.
This article discusses the potential benefits of deep insertion which are obtained using pitch-locked temporal stimulation patterns. Besides the access to low frequency information, further advantages of deeply inserted long electrodes are the possibility to better approximate the correct tonotopic location of contacts, the coverage of a wider range of cochlear locations, and the somewhat reduced channel interaction due to the wider contact separation for a given number of channels. A newly developed set of strategies has been shown to improve speech understanding in noise and to enhance sound quality by providing a more &...
Source: Hearing Research - October 22, 2014 Category: Audiology Authors: Hochmair I, Hochmair E, Nopp P, Waller M, Jolly C Tags: Hear Res Source Type: research
Disparities in auditory physiology and pathology between C57BL/6J and C57BL/6N substrains.
Abstract C57BL/6 inbred mice are frequently used as models in auditory research, mostly the C57BL/6J and C57BL/6N substrains. Genetic variation and phenotypic disparities between these two substrains have been extensively investigated, but conflicting information exists about differences in their auditory and vestibular phenotypes. Literature-based comparisons are rendered difficult or impossible because most auditory publications do not designate the substrain used. We therefore evaluated commercial C57BL/6N and C57BL/6J mice for their baseline auditory brainstem response (ABR) thresholds at 3 months of age as we...
Source: Hearing Research - October 22, 2014 Category: Audiology Authors: Kendall A, Schacht J Tags: Hear Res Source Type: research
Perception and coding of interaural time differences with bilateral cochlear implants.
This article is part of a Special Issue entitled . PMID: 25456088 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 19, 2014 Category: Audiology Authors: Laback B, Egger K, Majdak P Tags: Hear Res Source Type: research
PET-imaging of brain plasticity after cochlear implantation.
This article is part of a Special Issue entitled . PMID: 25448166 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 16, 2014 Category: Audiology Authors: Strelnikov K, Marx M, Lagleyre S, Fraysse B, Deguine O, Barone P Tags: Hear Res Source Type: research
Voice emotion recognition by cochlear-implanted children and their normally-hearing peers.
This article is part of a Special Issue entitled . PMID: 25448167 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 16, 2014 Category: Audiology Authors: Chatterjee M, Zion DJ, Deroche ML, Burianek BA, Limb CJ, Goren AP, Kulkarni AM, Christensen JA Tags: Hear Res Source Type: research
Tinnitus and Neural Plasticity (Tonndorf lecture at XI(th) International Tinnitus Seminar, Berlin, 2014).
Abstract Ten years ago, animal models of noise-induced hearing loss predicted three cortical neural correlates of tinnitus resulting from noise-induced hearing loss: increased spontaneous firing rates, increased neural synchrony, and reorganization of tonotopic maps. Salicylate also induces tinnitus, however, the cortical correlates were reduced spontaneous firing rates, unchanged neural synchrony but some change to the tonotopic map. In both conditions increased central gain, potentially a correlate of hyperacusis, was found. Behavioral animal models suggested that tinnitus occurred, albeit not in all cases. The ...
Source: Hearing Research - October 11, 2014 Category: Audiology Authors: Eggermont JJ Tags: Hear Res Source Type: research
Electric-acoustic interactions in the hearing cochlea: single fiber recordings.
Abstract 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-level dependent response ar...
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Tillein J, Hartmann R, Kral A Tags: Hear Res Source Type: research
Cellular Immunologic responses to cochlear implantation In the human.
In conclusion, a cochlear implant generates a vigorous cellular immune response consisting of B and T lymphocytes, foreign body giant cells, and macrophages. Platinum was identified as one of the antigens likely responsible for this cellular response. This foreign body response may in certain cases result in migration or even extrusion of an implant device. PMID: 25285622 [PubMed - as supplied by publisher] (Source: Hearing Research)
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Nadol JB, O'Malley JT, Burgess BJ, Galler D Tags: Hear Res Source Type: research
An examination of the effects of broadband air-conduction masker on the speech intelligibility of speech-modulated bone-conduction ultrasound.
In this study, eight volunteers with normal hearing participated. The intelligibilities of speech-modulated BCU were measured using a numeral word list under masking conditions. Because the masker can mask the demodulated sounds, the evaluation of the masking reveals the contribution of the demodulation to the recognition of speech-modulated BCU. In the current results, the masking of speech-modulated BCU differed from that of original non-modulated speech. Although the masking shifted the recognition curve for the original speech upward, the same results were not observed for the speech-modulated BCU. The masking generate...
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Nishimura T, Okayasu T, Saito O, Shimokura R, Yamashita A, Yamanaka T, Hosoi H, Kitahara T Tags: Hear Res Source Type: research
Factors constraining the benefit to speech understanding of combining information from low-frequency hearing and a cochlear implant.
In this study we assessed the role of three factors in determining the magnitude of bimodal benefit -- (i) the level of CI-only performance, (ii) the magnitude of the hearing loss in the ear with low-frequency acoustic hearing and (iii) the type of test material. The patients had low-frequency PTAs (average of 125, 250 and 500 Hz) varying over a large range (70 dB HL) in the ear contralateral to the implant. The patients were tested with (i) CNC words presented in quiet (n=105) (ii) AzBio sentences presented in quiet (n=102), (iii) AzBio sentences in noise at +10 dB signal-to-noise ratio (SNR) (n=69), and (iv) AzBio senten...
Source: Hearing Research - October 3, 2014 Category: Audiology Authors: Dorman MF, Cook S, Spahr T, Zhang T, Loiselle L, Schramm D, Whittingham J, Gifford R Tags: Hear Res Source Type: research
Development and Evaluation of the Nurotron 26-Electrode Cochlear Implant System.
The objective measures show that electrode impedance decreased within the first month of device use, but was stable until a slight increase at the end of two years. The subjective loudness measures show that electric stimulation threshold was stable while the maximal comfort level increased over the 3 years. Mandarin sentence recognition increased from the pre-surgical 0%-correct score to a plateau of about 80% correct with 6-month use of the device. Both indirect and direct comparisons indicate indistinguishable performance differences between the Nurotron system and other commercially available devices. The present 26-el...
Source: Hearing Research - October 1, 2014 Category: Audiology Authors: Zeng FG, Rebscher SJ, Fu QJ, Chen H, Sun X, Yin L, Ping L, Feng H, Yang S, Gong S, Yang B, Kang HY, Gao N, Chi F Tags: Hear Res Source Type: research
Structural alterations of brain grey and white matter in early deaf adults.
Abstract Functional and structural brain alterations in the absence of the auditory input have been described, but the observed structural brain changes in the deaf are not uniform. Some of the previous researchers focused only on the auditory areas, while others investigated the whole brain or other selected regions of interest. Majority of studies revealed decreased white matter (WM) volume or altered WM microstructure and preserved grey matter (GM) structure of the auditory areas in the deaf. However, preserved WM and increased or decreased GM volume of the auditory areas in the deaf have also been reported. Se...
Source: Hearing Research - September 25, 2014 Category: Audiology Authors: Hribar M, Suput D, Carvalho AA, Battelino S, Vovk A Tags: Hear Res Source Type: research
Sensitivity, specificity and efficiency of speech-evoked ABR.
Abstract We determined the sensitivity, specificity and efficiency of speech-evoked Auditory Brainstem Response (ABR) as a diagnostic support for Auditory Processing Disorder (APD) and specific language impairment (SLI). Speech-evoked ABRs were elicited using the five-formant syllable/da/. The waveforms V, A, C, D, E, F, and O of all groups were analyzed. The sensitivity and specificity were calculated, and receiver operating characteristic analyses were performed to determine the optimum cut-off. Seventy-five children who were native speakers of Brazilian-Portuguese participated. The participants included 25 chil...
Source: Hearing Research - September 25, 2014 Category: Audiology Authors: Rocha-Muniz CN, Befi-Lopes DM, Schochat E Tags: Hear Res Source Type: research
Response to best-frequency tone bursts in the ventral cochlear nucleus is governed by ordered inter-spike interval statistics.
Abstract The spike-trains generated by short constant-amplitude constant-frequency tone bursts in the ventral cochlear nucleus of the anaesthetised guinea pig are examined. Spikes are grouped according to the order in which they occur following the onset of the stimulus. It is found that successive inter-spike intervals have low statistical dependence according to information-theoretic measures. This is in contrast to previous observations with long duration tone bursts in the cat dorsal and posteroventral cochlear nuclei and lateral superior olive, where it was found that long intervals tended to be followed by s...
Source: Hearing Research - September 24, 2014 Category: Audiology Authors: Wright MC, Winter IM, Forster JJ, Bleeck S Tags: Hear Res Source Type: research
Importance of cochlear health for implant function.
Abstract Amazing progress has been made in providing useful hearing to hearing-impaired individuals using cochlear implants, but challenges remain. One such challenge is understanding the effects of partial degeneration of the auditory nerve, the target of cochlear implant stimulation. Here we review studies from our human and animal laboratories aimed at characterizing the health of the implanted cochlea and the auditory nerve. We use the data on cochlear and neural health to guide rehabilitation strategies. The data also motivate the development of tissue-engineering procedures to preserve or build a healthy coc...
Source: Hearing Research - September 24, 2014 Category: Audiology Authors: Pfingst BE, Zhou N, Colesa DJ, Watts MM, Strahl SB, Garadat SN, Schvartz-Leyzac KC, Budenz CL, Raphael Y, Zwolan TA Tags: Hear Res Source Type: research
Simultaneous comparison of two sound Localization Measures.
Abstract Almost all behavioral studies of sound localization have used either an approach-to-target or pointing/orienting task to assess absolute sound localization performance, yet there are very few direct comparisons of these measures. In an approach-to-target task, the subject is trained to walk to a sound source from a fixed location. In an orienting task, finger, head and/or eye movements are monitored while the subject's body is typically constrained. The fact that subjects may also initiate head and eye movements toward the target during the approach-to-target task allows us to measure the accuracy of the ...
Source: Hearing Research - September 24, 2014 Category: Audiology Authors: Jones AE, Ruhland JL, Gai Y, Yin TC Tags: Hear Res Source Type: research
Amplitude-modulation detection by recreational-noise-exposed humans with near-normal hearing thresholds and its medium-term progression.
Abstract Noise exposure can affect the functioning of cochlear inner and outer hair cells (IHC/OHC), leading to multiple perceptual changes. This work explored possible changes in detection of amplitude modulation (AM) at three Sensation Levels (SL) for carrier frequencies of 3, 4 and 6 kHz. There were two groups of participants, aged 19 to 24 (Young) and 26 to 35 (Older) years. All had near-normal audiometric thresholds. Participants self-assessed exposure to high-level noise in recreational settings. Each group was sub-grouped into low-noise (LN) or high-noise (HN) exposure. AM detection thresholds were worse fo...
Source: Hearing Research - September 23, 2014 Category: Audiology Authors: Stone MA, Moore BC Tags: Hear Res Source Type: research
Correlations of decision weights and cognitive function for the masked discrimination of vowels by young and old adults.
Abstract Older adults are often reported in the literature to have greater difficulty than younger adults understanding speech in noise [Helfer and Wilber (1988). J. Acoust. Soc. Am, 859-893]. The poorer performance of older adults has been attributed to a general deterioration of cognitive processing, deterioration of cochlear anatomy, and/or greater difficulty segregating speech from noise. The current work used perturbation analysis [Berg(1990). J. Acoust. Soc. Am., 149-158] to provide a more specific assessment of the effect of cognitive factors on speech perception in noise. Sixteen older (age 56-79 years) an...
Source: Hearing Research - September 22, 2014 Category: Audiology Authors: Gilbertson L, Lutfi RA Tags: Hear Res Source Type: research