Indications of Effective Hyperbaric Oxygen Therapy Combined With Steroid Therapy for Sudden Hearing Loss.

OBJECTIVE: This study evaluated the therapeutic effect of hyperbaric oxygen therapy (HBOT) combined with steroid therapy to treat sudden hearing loss and examined the index associated with excellent therapeutic effect. METHODS: We included 109 patients with sudden hearing loss. Patients were divided into the HBOT combination group (59 sides) treated with HBOT and steroid therapy and HBOT noncombination group (50 sides) involving steroid therapy only. The recovery rate of each group was compared according to the severity of hearing loss. Blood samples were evaluated and inflammatory markers, such as neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR), were calculated and compared by severity. We evaluated the usefulness of inflammatory markers for predicting recovery rate, and calculated cutoff values were also evaluated. RESULTS: The HBOT combination group exhibited a higher overall recovery rate than the HBOT noncombination group, particularly in severe cases. However, there was no significant difference in the severity of hearing loss based on various inflammatory markers. NLR and PLR are useful for predicting the effect in patients treated with concomitant HBOT. By setting 2.43 and 146.67 as cutoff values for NLR and PLR, respectively, we observed that lower values resulted in better recovery rates. CONCLUSION: The use of HBOT is effective for severe cases and early blood flow disorders with low NLR and PLR and less inflammation. When determining treatment, not only should the severity of hearing loss be considered, but also the NLR and PLR should be evaluated and examined based on the cutoff values.

Usos de cámara hiperbárica en otorrinolaringología / Uses for hyperbaric chambers in otolaryngology

Resumen En la terapia con oxígeno hiperbárico (HBO) se utiliza oxígeno al 100% de concentración en una cámara presurizada con presiones supraatmosféricas, que corresponden de 2 a 3 atmósferas. Los mecanismos por los cuales funciona esta terapia se relacionan con propiedades físicas de los gases y su comportamiento fisiológico en el organismo, lo que lleva finalmente a la hiperoxia, evento fisiológico que permite la obtención de diversos efectos beneficiosos. La evidencia en medicina ha demostrado su utilidad mayormente en la enfermedad por descompresión, infecciones cutáneas graves e intoxicación por monóxido de carbono. En el ámbito de la otorrinolaringología ha probado ser útil en algunas enfermedades como la hipoacusia súbita idiopática, tanto como terapia única como asociada al uso de corticosteroides, como en la osteomielitis refractaria del oído externo, la que en conjunto con antibioticoterapia y manejo quirúrgico presenta un evidente aumento en la tasa de mejoría. Cabe mencionar que la terapia con HBO ha demostrado también beneficios en los tratamientos y complicaciones posteriores a la radiación en pacientes con cáncer de cabeza y cuello. Es importante mencionar que la terapia con HBO no está exenta de riesgos y requiere que los pacientes cumplan con características específicas para su utilización, por lo que su indicación debe ser juiciosa y en casos seleccionados.

Abstract In hyperbaric oxygen therapy, 100% pure oxygen is used in a pressurized chamber with super atmospheric pressures which correspond to 2-3 atmospheres. The mechanism by which this treatment works is related to the physical properties of gases and their physiological behavior in the body, which leads to hyperoxia, the physiological event which allows for diverse beneficial health effects. The evidence in medicine has proven its utility mainly in decompression sickness, severe skin infections and carbon monoxide poisoning. In the otolaryngology field it has been proven useful in diseases like idiopathic sudden sensorineural hearing loss, both as the only treatment and as a concurrent treatment along with corticosteroids, in malignant otitis externa which in conjunction with antibiotic treatment and a surgical approach presents a clear increase in improvement rates. It must be mentioned that hyperbaric chamber treatment has also shown benefits in radiation treatment and post radiation complications in head and neck cancer patients. It is important to note that hyperbaric oxygen therapy is not without risks and patients must meet specific criteria for it to be applied, therefore it must be indicated using careful judgement and only in necessary cases.

Provision of interaural time difference information in chronic intracochlear electrical stimulation enhances neural sensitivity to these differences in neonatally deafened cats.

Although performance with bilateral cochlear implants is superior to that with a unilateral implant, bilateral implantees have poor performance in sound localisation and in speech discrimination in noise compared to normal hearing subjects. Studies of the neural processing of interaural time differences (ITDs) in the inferior colliculus (IC) of long-term deaf animals, show substantial degradation compared to that in normal hearing animals. It is not known whether this degradation can be ameliorated by chronic cochlear electrical stimulation, but such amelioration is unlikely to be achieved using current clinical speech processors and cochlear implants, which do not provide good ITD cues. We therefore developed a custom sound processor to deliver salient ITDs for chronic bilateral intra-cochlear electrical stimulation in a cat model of neonatal deafness, to determine if long-term exposure to salient ITDs would prevent degradation of ITD processing. We compared the sensitivity to ITDs in cochlear electrical stimuli of neurons in the IC of cats chronically stimulated with our custom ITD-aware sound processor with sensitivity in acutely deafened cats with normal hearing development and in cats chronically stimulated with a clinical stimulator and sound processor. Animals that experienced stimulation with our custom ITD-aware sound processor had significantly higher neural sensitivity to ITDs than those that received stimulation from clinical sound processors. There was no significant difference between animals received no stimulation and those that received stimulation from clinical sound processors, consistent with findings from clinical cochlear implant users. This result suggests that development and use of clinical ITD-aware sound processing strategies from a young age may promote ITD sensitivity in the clinical population.

Effects of a mind-body program on symptoms of depression and perceived stress among adults with neurofibromatosis type 2 who are deaf: A live-video randomized controlled trial.

INTRODUCTION: Neurofibromatosis type 2 (NF2) is a rare, progressive and incurable genetic disorder associated with progressive hearing loss and eventual deafness. As a group, patients with NF report high levels of stress and depressive symptoms. However, no studies have explored improvement in these symptoms after psychosocial interventions. We have previously shown that a mind-body program tailored to adults with NF2 who are deaf (the Relaxation Response and Resiliency Program for Deaf NF2, d3RP-NF2) improves quality of life and resiliency over and above a Health Enhancement program when both are delivered via live-video and assisted by Communication Access Realtime Translation (CART). Here we tested the effects of the programs on depression and perceived stress. METHODS: Forty-five patients with NF2 and significant hearing loss were randomized to the d3RP-NF2 or Health-Enhancement program and completed measures of depression (PHQ-9) and perceived stress (PSS-10) at baseline, post-intervention, and six-month follow-up. RESULTS: Patients randomized to the d3RP-NF2 program, but not to the control condition, experienced significant decreases on both measures from baseline to post-test, which were maintained at follow-up (within group tests). However, improvements following the d3RP-NF2 program was not significantly higher than those observed in the control group (between group tests). CONCLUSION: Results provide the first evidence of improvement in symptoms of depression and perceived stress among deaf patients living with NF2 who participate in a virtual mind-body program.

Consistent and chronic cochlear implant use partially reverses cortical effects of single sided deafness in children.

Potentially neuroprotective effects of CI use were studied in 22 children with single sided deafness (SSD). Auditory-evoked EEG confirmed strengthened representation of the intact ear in the ipsilateral auditory cortex at initial CI activation in children with early-onset SSD (n = 15) and late-onset SSD occurring suddenly in later childhood/adolescence (n = 7). In early-onset SSD, representation of the hearing ear decreased with chronic CI experience and expected lateralization to the contralateral auditory cortex from the CI increased with longer daily CI use. In late-onset SSD, abnormally high activity from the intact ear in the ipsilateral cortex reduced, but responses from the deaf ear weakened despite CI use. Results suggest that: (1) cortical reorganization driven by unilateral hearing can occur throughout childhood; (2) chronic and consistent CI use can partially reverse these effects; and (3) CI use may not protect children with late-onset SSD from ongoing deterioration of pathways from the deaf ear.

The perception of the stereo effect in bilateral and bimodal cochlear implant users and its contribution to music enjoyment.

OBJECTIVES: In this clinical study, stereo perception of music samples and its contribution to music enjoyment in CI users is investigated. It is studied in free field as well as direct audio presentation. METHODS: 20 bilateral and 9 bimodal CI users performed stereo detection tests and music enjoyment ratings. Music was presented either in mono or in stereo in free field or with direct audio presentation. Stereo detection was assessed with a 3-AFC paradigm. Music enjoyment was studied with scale ratings. RESULTS: For bilateral CI users, stereo detection increased from 52% correct in free field to 86% with direct audio presentation. Increased music enjoyment with improved stereo detection was obtained. Bimodal CI users could not identify stereo sounds. Music enjoyment did not increase for stereo presentations in bimodal subjects. DISCUSSION: For bilateral CI users, improved stereo detection might increase music enjoyment with direct audio presentation, which is likely due to bypassing the room acoustics. In bimodal CI users, no clear improvement was found, which is likely attributed due to the different hearing losses and therefore individually different interaural frequency overlaps between the hearing aid and the cochlear implant. CONCLUSION: Direct audio presentation is an efficient method to improve music enjoyment in bilateral CI users.

Enhanced Pitch Discrimination for Cochlear Implant Users with a New Haptic Neuroprosthetic.

The cochlear implant (CI) is the most widely used neuroprosthesis, recovering hearing for more than half a million severely-to-profoundly hearing-impaired people. However, CIs still have significant limitations, with users having severely impaired pitch perception. Pitch is critical to speech understanding (particularly in noise), to separating different sounds in complex acoustic environments, and to music enjoyment. In recent decades, researchers have attempted to overcome shortcomings in CIs by improving implant technology and surgical techniques, but with limited success. In the current study, we take a new approach of providing missing pitch information through haptic stimulation on the forearm, using our new mosaicOne_B device. The mosaicOne_B extracts pitch information in real-time and presents it via 12 motors that are arranged in ascending pitch along the forearm, with each motor representing a different pitch. In normal-hearing subjects listening to CI simulated audio, we showed that participants were able to discriminate pitch differences at a similar performance level to that achieved by normal-hearing listeners. Furthermore, the device was shown to be highly robust to background noise. This enhanced pitch discrimination has the potential to significantly improve music perception, speech recognition, and speech prosody perception in CI users.

Itinerário terapêutico da criança surda na rede de atenção à saúde / Therapeutic itinerary of a deaf child in the Network of Health Care / Itinerario terapéutico de ninõs sordos en la red de atención a la salud

Introdução: Na criança, a existência da deficiência auditiva é ainda mais preocupante que no adulto ou idoso, devido à interferência no processo de aquisição e desenvolvimento da linguagem. Por esse motivo, é preciso que haja uma rede de atenção à saúde organizada de modo a oferecer diagnóstico e intervenção rapidamente. Objetivo: Analisar a atenção à saúde auditiva infantil a partir do itinerário terapêutico (IT) de uma criança surda usuária de um Centro de Reabilitação Auditiva. Método: A pesquisa, de natureza qualitativa e do tipo estudo de caso, foi realizada tomando-se como ponto de partida um município da região de Campinas/SP, os serviços da rede municipal de saúde e referências regionais. Foi feita entrevista em profundidade com a mãe da criança para reconstituição do IT e 10 entrevistas semiestruturadas com gestores e profissionais para obter informações sobre a linha de cuidado à saúde auditiva. Resultados: A maternidade foi um importante ponto de atenção para detecção precoce da deficiência auditiva, porém há falhas no protocolo de triagem utilizado por ela. O Centro de Reabilitação cumpria com seu papel, mas foi apontada a necessidade de serviços de reabilitação nas cidades de origem dos usuários. Houve problemas na coordenação do cuidado da Unidade Básica de Saúde de referência para a criança surda. Conclusão: A reconstituição do IT foi uma importante ferramenta para analisar a integralidade na atenção à saúde, permitindo compreender a trajetória real do usuário na busca por cuidado, permitindo que se conheça e como funciona a rede real de atenção à saúde.

Introduction: In children, hearing impairment is more serious than in adults or elders, because it interferes in the language acquisition and development. For this reason, there must be a healthcare network aimed at offering diagnoses and medical intervention quickly. Objective: to analyze child hearing care as from the therapeutic itinerary (TI) of a deaf child using the services of a Centro de Reabilitação Auditiva (Hearing Rehabilitation Centre). Methods: this research is a case study of qualitative nature. Our starting point was the health services of a city in the urban area of Campinas/SP, and also some regional references. We conducted an in-depth interview with the child's mother for the reconstruction of the TI and 10 semi-structured interviews with managers and professionals in order to obtain information about the type of hearing care. Results: the maternity unit was important for the early detection of hearing impairment, but there were flaws in the screening protocol it employed. The Rehabilitation Centre fulfilled its role, but there was an unmet need of rehabilitation services in the home city of the users. There were also flaws in the healthcare coordination of the Unidade Básica de Saúde (Primary Health Unit) for deaf children. Conclusion: The reconstruction of the TI was an important tool to analyze the completeness of attention to health services, allowing us to understand the user's real story in the search for health care and the way the healthcare network operates.

Introducción: La existencia de discapacidad auditiva es más preocupante en el niño que en el adulto o el anciano debido a la interferencia en el proceso de adquisición y desarrollo del lenguaje, siendo necesario que haya una red de salud organizada que ofrezca un diagnóstico e intervención oportunas. Objetivo: Analizar la atención a la salud auditiva infantil partiendo del itinerario terapéutico (IT) de un niño sordo usuario de un Centro de Rehabilitación Auditiva. Método: La investigación cualitativa, de tipo estudio de caso, consideró: servicios de la red municipal de salud de una ciudad de la región de Campinas/SP y referencias regionales. Fue realizada una entrevista en profundidad con la madre del niño para la reconstitución del IT y 10 entrevistas semiestructuradas con gestores y profesionales para obtener información sobre la línea de cuidado a la salud auditiva. Resultados: La maternidad fue un importante punto de atención para la detección temprana de la discapacidad auditiva, aunque con fallas en su protocolo de cribado. El Centro de Rehabilitación cumplía con su papel, pero fue señalada la necesidad de estos servicios en las ciudades de origen de los usuarios. Hubo problemas en la coordinación del cuidado de la Unidad Primaria de Salud de referencia para el niño sordo. Conclusión: La reconstitución del IT fue una herramienta importante para analizar la integralidad a la salud, permitiendo tanto comprender la trayectoria real del usuario en la búsqueda por atención, como que se conozca la red real de atención a la salud y su funcionamiento.

Auditory Selective Attention Hindered by Visual Stimulus in Prelingually Deaf Children With Cochlear Implants.

OBJECTIVE: To compare the influence of visual distractors on the performance of auditory selective attention between prelingually deaf children with a CI (cochlear implant) and children with normal-hearing. DESIGN: Twenty-two patients who had a cochlear implant device (10 males and 12 females, aged 6.64 ±â€Š0.99 yrs) and 16 normal-hearing children (6 males and 10 females, aged 6.09 ±â€Š0.51 yrs) were recruited. Half of the auditory stimuli were presented together with visual stimuli, and participants were required to complete an auditory identification task. Reaction times and discriminability (d') for these two groups were recorded and calculated. RESULTS: The normal-hearing group had shorter mean reaction times than the CI group in detecting auditory targets. With visual distraction, the d' of the normal-hearing group was significantly better than that of CI group (t = 2.649, p = 0.012), while no statistical significance was found between the two groups without visual distraction (t = 0.693, p = 0.493). CONCLUSION: Enhanced processing of visual stimuli interferes with auditory perception in CI users by occupying the capacity-limited attention.

A mouse model of cochlear implantation with chronic electric stimulation.

OBJECTIVES: Cochlear implants provide an effective treatment option for those with severe hearing loss, including those with preserved low frequency hearing. However, certain issues can reduce implant efficacy including intracochlear tissue response and delayed loss of residual acoustic hearing. We describe a mouse model of cochlear implantation with chronic electric stimulation that can be used to study cochlear implant biology and related pathologies. METHODS: Twelve normal hearing adult CBA/J mice underwent unilateral cochlear implantation and were evenly divided into one group receiving electric stimulation and one not. Serial impedance and neural response telemetry (NRT) measurements were made to assess implant functionality. Functionality was defined as having at least one electrode with an impedance ≤ 35 kOhms. Mouse cochleae were harvested for histology and 3D x-ray microscopy 21 days post-operatively, or, in case the implant was still functional, at a later time point when the implant failed. A separate experiment measured the hearing preservation rate in 7 adult CBA/J mice undergoing unilateral cochlear implantation with serial auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE). RESULTS: Implants maintained functionality for a mean of 35 days in the non-stimulated group and 19.8 days in the stimulated group. Reliable NRT and behavioral responses to electric stimulation were recorded. A robust intracochlear peri-implant tissue response with neo-ossification was seen in all cochleae. Six of seven mice maintained intact low frequency hearing up to 6 weeks following cochlear implantation. CONCLUSIONS: We demonstrate the feasibility of cochlear implantation and behaviorally significant electric stimulation in the mouse, with the potential for hearing preservation. This model may be combined with established mouse models of hearing loss and the large genetic and molecular research toolkit unique to the mouse for mechanistic and therapeutic investigations of cochlear implant biology.

Electro-Natural Stimulation in Partial Deafness Treatment of Adult Cochlear Implant Users: Long-Term Hearing Preservation Results.

BACKGROUND: Due to the constant development of technology and medicine, the eligibility criteria for cochlear implantation (CI) are undergoing gradual expansion. OBJECTIVES: To provide long-term hearing preservation (HP) results for partial deafness treatment (PDT) of a group of adults using electro-natural stimulation (ENS). METHODS: We examined a database of medical records of patients who underwent CI in a single ENT center. We identified 12 adults (3 men and 9 women) who fitted the PDT-ENS classification. To calculate HP, we used the -HEARRING consensus and conducted statistical analyses using SPSS v24. RESULTS: In the long-term follow-up, 7 of 12 patients had complete HP and the remaining 5 had partial HP. None of the patients experienced significant hearing impairment. A significant improvement in speech understanding in both quiet and noise conditions was also observed. CONCLUSIONS: The use of minimally invasive surgery leads to excellent HP results in PDT-ENS patients, enabling them to enjoy the benefits of good speech discrimination which they would be unable to get from traditional hearing aids. Our findings support extending the inclusion criteria for CI to include this new group of patients who would otherwise obtain only limited benefit from conventional hearing aids.

Optimizing maps for electric acoustic stimulation users.

OBJECTIVES: To optimize patient's maps in Electric Acoustic Stimulation (EAS) users based on the degree of post-operative aided hearing thresholds. METHODS: Twenty-one adult EAS patients participated in this study. Patients were subdivided into three groups, based on their unaided hearing threshold: (1) electric complementary (EC, n = 6) patients with ≤30 dB HL at 125-500 Hz with severe to profound hearing loss at higher frequencies who only use electric stimulation, (2) EAS (n = 8) patients with 30-70 dB HL from 125 to 250 Hz and profound hearing loss in high frequencies who use combined EAS, and (3) Marginal-EAS (M-EAS, n = 7) patients with 70-95 dB HL at frequencies ≤250 Hz who use combined EAS. Sentence perception in noise, melodic contour identification, and subjective preference were measured using Full Overlap, Narrow Overlap, Gap, and Meet maps. RESULT: Of the 21 patients that participated, 12 subjects were classified as complete hearing preservation and 9 subjects were classified as partial hearing preservation. The highest performing maps in sentence-in-noise perception and melodic contour identification were Gap, Meet, and Full Overlap for the EC, EAS, and the M-EAS groups, respectively. These results are consistently across different test materials and align with subject preference as well. CONCLUSION: These results suggest that clinical fitting in EAS listening should be individually tailored. EAS performance can be enhanced by optimizing maps between acoustic and electric stimulation based on the degree of aided hearing thresholds.

Impedance measures for a better understanding of the electrical stimulation of the inner ear.

The performance of cochlear implant (CI) listeners is limited by several factors among which the lack of spatial selectivity of the electrical stimulation. Recently, many studies have explored the use of multipolar strategies where several electrodes are stimulated simultaneously to focus the electrical field in a restricted region of the cochlea. OBJECTIVE: These strategies are based on several assumptions concerning the electrical properties of the inner ear that need validation. The first, often implicit, assumption is that the medium is purely resistive and that the current waveforms produced by several electrodes sum linearly. The second assumption relates to the estimation of the contribution of each electrode to the overall electrical field. These individual contributions are usually obtained by stimulating each electrode and measuring the resulting voltage with the other inactive electrodes (i.e. the impedance matrix). However, measuring the voltage on active electrodes (i.e. the diagonal of the matrix) is not straightforward because of the polarization of the electrode-fluid interface. In existing multipolar strategies, the diagonal terms of the matrix are therefore inferred using linear extrapolation from measurements made at neighboring electrodes. APPROACH: In experiment 1, several impedance measurements were carried out in vitro and in eight CI users using sinusoidal and pulsatile waveforms to test the resistivity and linearity hypotheses. In experiment 2, we used an equivalent electrical model including a constant phase element in order to isolate the polarization component of the contact impedance. MAIN RESULTS: In experiment 1, high-resolution voltage recordings (1.1 MHz sampling) showed the resistivity assumption to be valid at 46.4 kHz, the highest frequency tested. However, these measures also revealed the presence of parasitic capacitive effects at high frequency that could be deleterious to multipolar strategies. Experiment 2 showed that the electrical model provides a better account of the high-resolution impedance measurements than previous approaches in the CI field that used resistor-capacitance circuit models. SIGNIFICANCE: These results validate the main hypotheses underlying the use of multipolar stimulation but also suggest possible modifications to their implementation, including the use of an impedance model and the modification of the electrical pulse waveform.

Potential Application of Electrical Stimulation in Stem Cell-Based Treatment against Hearing Loss.

Deafness is a common human disease, which is mainly caused by irreversible damage to hair cells and spiral ganglion neurons (SGNs) in the mammalian cochlea. At present, replacement of damaged or missing hair cells and SGNs by stem cell transplantation therapy is an effective treatment. However, the survival rate of stem cell transplantation is low, with uncontrollable differentiation hindering its application. Most researchers have focused on biochemical factors to regulate the growth and differentiation of stem cells, whereas little study has been performed using physical factors. This review intends to illustrate the current problems in stem cell-based treatment against deafness and to introduce electric field stimulation as a physical factor to regulate stem cell behavior and facilitate stem cell therapy to treat hearing loss in the future.

Auditory Neural Activity in Congenitally Deaf Mice Induced by Infrared Neural Stimulation.

To determine whether responses during infrared neural stimulation (INS) result from the direct interaction with spiral ganglion neurons (SGNs), we tested three genetically modified deaf mouse models: Atoh1-cre; Atoh1 f/f (Atoh1 conditional knockout, CKO), Atoh1-cre; Atoh1 f/kiNeurog1 (Neurog1 knockin, KI), and the Vglut3 knockout (Vglut3 -/-) mice. All animals were exposed to tone bursts and clicks up to 107 dB (re 20 µPa) and to INS, delivered with a 200 µm optical fiber. The wavelength (λ) was 1860 nm, the radiant energy (Q) 0-800 µJ/pulse, and the pulse width (PW) 100-500 µs. No auditory responses to acoustic stimuli could be evoked in any of these animals. INS could not evoke auditory brainstem responses in Atoh1 CKO mice but could in Neurog1 KI and Vglut3 -/- mice. X-ray micro-computed tomography of the cochleae showed that responses correlated with the presence of SGNs and hair cells. Results in Neurog1 KI mice do not support a mechanical stimulation through the vibration of the basilar membrane, but cannot rule out the direct activation of the inner hair cells. Results in Vglut3 -/- mice, which have no synaptic transmission between inner hair cells and SGNs, suggested that hair cells are not required.

Delayed access to bilateral input alters cortical organization in children with asymmetric hearing.

Bilateral hearing in early development protects auditory cortices from reorganizing to prefer the better ear. Yet, such protection could be disrupted by mismatched bilateral input in children with asymmetric hearing who require electric stimulation of the auditory nerve from a cochlear implant in their deaf ear and amplified acoustic sound from a hearing aid in their better ear (bimodal hearing). Cortical responses to bimodal stimulation were measured by electroencephalography in 34 bimodal users and 16 age-matched peers with normal hearing, and compared with the same measures previously reported for 28 age-matched bilateral implant users. Both auditory cortices increasingly favoured the better ear with delay to implanting the deaf ear; the time course mirrored that occurring with delay to bilateral implantation in unilateral implant users. Preference for the implanted ear tended to occur with ongoing implant use when hearing was poor in the non-implanted ear. Speech perception deteriorated with longer deprivation and poorer access to high-frequencies. Thus, cortical preference develops in children with asymmetric hearing but can be avoided by early provision of balanced bimodal stimulation. Although electric and acoustic stimulation differ, these inputs can work sympathetically when used bilaterally given sufficient hearing in the non-implanted ear.

Auditory and cognitive development in a partially deaf child with bilateral electro-acoustic stimulation: a case study.

OBJECTIVE: To study the long-term evolution of speech and intelligence in a child with partial deafness and normal hearing in the low frequencies after sequentially receiving cochlear implants in both ears. DESIGN: Retrospective chart review. STUDY SAMPLE: Male child aged 6 years was followed over a time period of four years. RESULTS: The paediatric patient had normal hearing up to 1 kHz and profound hearing loss at all higher frequencies symmetrical in both ears. Deprivation of high-frequency sounds resulted in retarded development of speech, language and cognitive skills. The choice for rehabilitation was cochlear implantation with the aim of preserving a considerable amount of low-frequency hearing. With natural hearing at low frequencies and electrical stimulation at high frequencies, the child was able to compensate most of his developmental deficits. Moreover, spatial hearing was almost normal. CONCLUSIONS: Electro-natural stimulation without amplification of the low frequencies (electro-natural hearing) provides access to the whole audible frequency range for children, who suffer from partial deafness in the high frequencies and are normal hearing at low frequencies. Such provision allows for regular speech development and favours the development of spatial hearing. The case report also demonstrates a strong impact on intellectual performance.

Head Shadow and Binaural Squelch for Unilaterally Deaf Cochlear Implantees.

BACKGROUND: Cochlear implants (CIs) can improve speech-in-noise performance for listeners with unilateral sensorineural deafness. But these benefits are modest and in most cases are limited to head-shadow advantages, with little evidence of binaural squelch. HYPOTHESIS: The goal of the investigation was to determine whether CI listeners with normal hearing or moderate hearing loss in the contralateral ear would receive a larger head-shadow benefit for target speech and noise originating from opposite sides of the head, and whether listeners would experience binaural squelch in the free field in a test involving interfering talkers. METHODS: Eleven CI listeners performed a speech-identification task in the presence of interfering noise or speech. Six listeners had single-sided deafness (normal or near-normal audiometric thresholds in the acoustic ear) and five had asymmetric hearing loss (hearing loss in the acoustic ear treated with a hearing aid). Listeners were tested with the acoustic ear only and bilaterally with the CI turned on. One set of conditions examined head-shadow effects with target speech and masking noise presented from azimuths of 0 or ±108 degrees. A second set of conditions examined binaural squelch, with target speech presented from the front and interfering talkers symmetrically placed on both sides. RESULTS: On average, the largest head-shadow benefit (5 dB) occurred when the target and masking noise were presented on opposite sides of the head. Listeners also showed an average of 2 dB of squelch, but only when the target speech was masked by interfering talkers of the same sex as the target. CONCLUSIONS: CIs provide listeners with unilateral deafness important benefits for speech perception in complex spatial environments, including a larger head-shadow benefit when speech and noise originate on opposite sides of the head, and an improved ability to perceptually organize an auditory scene with multiple competing voices.The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or US Government.

Pitch Matching between Electrical Stimulation of a Cochlear Implant and Acoustic Stimuli Presented to a Contralateral Ear with Residual Hearing.

BACKGROUND: Cochlear implants (CIs) successfully restore hearing in postlingually deaf adults, but in doing so impose a frequency-position function in the cochlea that may differ from the physiological one. PURPOSE: The CI-imposed frequency-position function is determined by the frequency allocation table programmed into the listener's speech processor and by the location of the electrode array along the cochlea. To what extent can postlingually deaf CI users successfully adapt to the difference between physiological and CI-imposed frequency-position functions? RESEARCH DESIGN: We attempt to answer the question by combining behavioral measures of electroacoustic pitch matching (PM) and measures of electrode location within the cochlea. STUDY SAMPLE: The participants in this study were 16 adult CI users with residual hearing who could match the pitch of acoustic pure tones presented to their unimplanted ears to the pitch resulting from stimulation of different CI electrodes. DATA COLLECTION AND ANALYSIS: We obtained data for four to eight apical electrodes from 16 participants with CIs (most of whom were long-term users), and estimated electrode insertion angle for 12 of these participants. PM functions in this group were compared with the two frequency-position functions discussed above. RESULTS: Taken together, the findings were consistent with the possibility that adaptation to the frequency-position function imposed by CIs does happen, but it is not always complete. CONCLUSIONS: Some electrodes continue to be perceived as higher pitched than the acoustic frequencies with which they are associated despite years of listening experience after cochlear implantation.

Behavioral Measures of Temporal Processing and Speech Perception in Cochlear Implant Users.

BACKGROUND: Although most cochlear implant (CI) users achieve improvements in speech perception, there is still a wide variability in speech perception outcomes. There is a growing body of literature that supports the relationship between individual differences in temporal processing and speech perception performance in CI users. Previous psychophysical studies have emphasized the importance of temporal acuity for overall speech perception performance. Measurement of gap detection thresholds (GDTs) is the most common measure currently used to assess temporal resolution. However, most GDT studies completed with CI participants used direct electrical stimulation not acoustic stimulation and they used psychoacoustic research paradigms that are not easy to administer clinically. Therefore, it is necessary to determine if the variance in GDTs assessed with clinical measures of temporal processing such as the Randomized Gap Detection Test (RGDT) can be used to explain the variability in speech perception performance. PURPOSE: The primary goal of this study was to investigate the relationship between temporal processing and speech perception performance in CI users. RESEARCH DESIGN: A correlational study investigating the relationship between behavioral GDTs (assessed with the RGDT or the Expanded Randomized Gap Detection Test) and commonly used speech perception measures (assessed with the Speech Recognition Test [SRT], Central Institute for the Deaf W-22 Word Recognition Test [W-22], Consonant-Nucleus-Consonant Test [CNC], Arizona Biomedical Sentence Recognition Test [AzBio], Bamford-Kowal-Bench Speech-in-Noise Test [BKB-SIN]). STUDY SAMPLE: Twelve postlingually deafened adult CI users (24-83 yr) and ten normal-hearing (NH; 22-30 yr) adults participated in the study. DATA COLLECTION AND ANALYSIS: The data were collected in a sound-attenuated test booth. After measuring pure-tone thresholds, GDTs and speech perception performance were measured. The difference in performance between-participant groups on the aforementioned tests, as well as the correlation between GDTs and speech perception performance was examined. The correlations between participants' biologic factors, performance on the RGDT and speech perception measures were also explored. RESULTS: Although some CI participants performed as well as the NH listeners, the majority of the CI participants displayed temporal processing impairments (GDTs > 20 msec) and poorer speech perception performance than NH participants. A statistically significant difference was found between the NH and CI test groups in GDTs and some speech tests (SRT, W-22, and BKB-SIN). For the CI group, there were significant correlations between GDTs and some measures of speech perception (CNC Phoneme, AzBio, BKB-SIN); however, no significant correlations were found between biographic factors and GDTs or speech perception performance. CONCLUSIONS: Results support the theory that the variability in temporal acuity in CI users contributes to the variability in speech performance. Results also indicate that it is reasonable to use the clinically available RGDT to identify CI users with temporal processing impairments for further appropriate rehabilitation.