Quality of life related to symptomatic outcomes in patients with vestibular schwannomas: A Canadian Centre perspective.

Patients with vestibular schwannomas (VS) typically present with hearing loss and tinnitus as well as variable cranial nerve dysfunctions. Surgical resection, stereotactic radiotherapy and/or conservative management employing serial magnetic resonance or computed tomography imaging serve as the main treatment options. Quality of life (QoL) may be impacted by the extent of tumour burden and exacerbated or relieved by treatment. Subjective assessment and quality of life inventories provide valuable information in client centered approaches with important implications for treatment. The intention of QoL measurements affecting VS patients within a clinical setting is to facilitate discussions regarding treatment options and objectively evaluate patient- centered clinical outcomes in a naturalistic setting.

Commentary on the regulatory implications of noise-induced cochlear neuropathy.

OBJECTIVE: A discussion on whether recent research on noise-induced cochlear neuropathy in rodents justifies changes in current regulation of occupational noise exposure. DESIGN: Informal literature review and commentary, relying on literature found in the authors' files. No formal literature search was performed. STUDY SAMPLE: Published literature on temporary threshold shift (TTS) and cochlear pathology, in humans and experimental animals, as well as the regulations of the US Occupational Safety and Health Administration (OSHA). RESULTS: Humans are less susceptible to TTS, and probably to cochlear neuropathy, than rodents. After correcting for inter-species audiometric differences (but not for differences in susceptibility), exposures that caused cochlear neuropathy in rodents already exceed OSHA limits. Those exposures also caused "pathological TTS" (requiring more than 24 h to recover), which does not appear to occur with human broadband noise exposure permissible under OSHA. CONCLUSION: It would be premature to conclude that noise exposures permissible under OSHA can cause cochlear neuropathy in humans.

Vestibular involvement in peripheral neuropathy: a review.

OBJECTIVE: This paper reviews the current literature on involvement of the vestibular division of the eighth cranial nerve in peripheral neuropathies. The literature abounds with references to auditory neuropathy, which is frequently related to more generalized neuropathies, but there is a marked paucity of work regarding vestibular neuropathy. A brief overview of neuropathies and the anatomy of the vestibulocochlear nerve provide the background for a review of the literature of vestibular nerve involvement in a range of neuropathies. DESIGN: A literature search including textbooks, and peer-reviewed published journal articles in online bibliographic databases was conducted. STUDY SAMPLE: Two databases for medical research were included in this review. RESULTS: The review of the literature indicates that vestibular involvement is a common and consistent finding in many peripheral neuropathies of different aetiologies. Specifically, if patients present unsteadiness/ataxia out of proportion to objective signs of somatosensory loss or muscle weakness. CONCLUSION: This review concludes that vestibular neuropathy, is common in peripheral neuropathy and should be identified to optimize patient management and rehabilitation.

Cochlear implantation for a child with cochlear nerve deficiency: parental perspectives explored through narrative.

OBJECTIVE: The objective of this study was to explore, from the parents' perspectives, decision-making regarding a cochlear implant (CI) for their child when a favourable outcome is less likely because of abnormal neurophysiology. DESIGN: The primary research method of this single case study was qualitative interviewing drawing on a narrative approach to elicit the parents' perspectives about their experiences over time. Each parent was interviewed separately, but thematic analyses were undertaken both within and across interviews in order to identify overlaps and differences. STUDY SAMPLE: Participants included the parents of a five-year old child with severe-profound hearing loss, cochlear nerve deficiency, and bilateral common cavities who had received a CI at the age of 18 months. RESULTS: Four themes were identified across the four narrative stages that emerged from the parents' accounts of their experiences regarding their daughter's CI. Themes included hope and despair, questioning professionals' motivations, does deafness need a cure, and bringing the child into the family. Although these themes emerged from both parents' accounts, each parent expressed different perspectives and insights within them. CONCLUSIONS: Findings highlight the central place of parental needs and perspectives in decision-making regarding a CI, particularly in the context of uncertain outcomes.

Perception of envelope-enhanced speech in the presence of noise by individuals with auditory neuropathy.

OBJECTIVE: To investigate the effect of background noise on perception of unprocessed and envelope-enhanced speech in individuals with auditory neuropathy (AN). DESIGN: Open-set speech identification abilities were assessed for unprocessed and envelope-enhanced speech in quiet and at three signal to noise ratios (10, 5, and 0 dB signal to noise ratio) in 15 individuals with AN. RESULTS: Results revealed that speech identification ability was affected more in the presence of noise than in quiet. The participants were classified into two groups, Good Performers and Poor Performers, based on their speech identification scores in quiet. It was observed that the reduction in mean speech identification scores in noise was less for Good Performers when compared with that of Poor Performers. Envelope enhancement of the signal improved speech identification scores in both the groups. The analysis of results also showed that Good Performers showed a significant improvement in all the conditions, whereas Poor Performers showed improvement only in quiet and +10 dB signal to noise ratio. CONCLUSIONS: For individuals with AN, listening in background noise is more difficult than in quiet condition. Envelope enhancement of speech signal improves speech identification scores in quiet and in background noise for individuals with AN. However, the benefit obtained varies depending on the speech identification ability in quiet.

Speech perception in children with auditory neuropathy/dyssynchrony managed with either hearing AIDS or cochlear implants.

OBJECTIVE: To evaluate speech perception skills in children with auditory neuropathy (AN)/auditory dyssynchrony (AD)-type hearing loss managed with either hearing aids or cochlear implants. STUDY DESIGN: Prospective data collection in 3 subject groups: AN/AD children fitted with bilateral amplification, AN/AD children fitted with cochlear implant (in 1 or both ears), and a matched control group of implanted children with sensorineural hearing loss. MAIN OUTCOME MEASURE: Open-set monosyllabic words (consonant-nucleus-consonant). RESULTS: Of the 10 implanted AN/AD children, 9 demonstrated significant speech discrimination (consonant-nucleus-consonant phoneme score > or =55%). Similar results were obtained for the aided AN/AD group. Findings for both AN/AD subject groups were poorer than those of the implanted sensorineural cohort. CONCLUSION: Cochlear implantation can offer useful hearing in subjects with AN/AD-type hearing loss. However, expectations for this group may need to be lower than for patients with peripheral (cochlear) loss.

Auditory perception in auditory neuropathy: clinical similarity with auditory verbal agnosia.

The precise features of auditory perception in patients with auditory neuropathy have not been well described. In the present study, we examined auditory perception in a patient with auditory neuropathy. The patient was a right-handed 7-year-old boy. His chief complaint was delayed speech and suspected of verbal learning disability. He could talk, read and repeat rather fluently but could not understand fully what was asked. V-IQ, P-IQ and F-IQ of Wechsler Scale for Children III-R were 53, 118 and 81, respectively. Pure tone audiogram was completely normal. His speech discrimination ability was very poor. He could identify environmental sounds with visual matching. He could differentiate intensity difference but not time difference. This phenomenon was reported in patients with hemispheric symptoms. These clinical features are very similar to verbal auditory agnosia. ABR showed no response at 90dBnHL alternating clicks and tone bursts. Click evoked and distortion product otoacoustic emissions (OAE) were normal. Electrocochleogram was also normal. Motor and sensory nerve conduction velocity was completely normal. Pa of MLR and N1 of SVR were present. His diagnosis should be "pure type" of auditory neuropathy or auditory nerve disease. Importance of both ABR and OAE examination should be widely announced and auditory neuropathy must be campaigned stressed to be clinical entity among personnel who take care of children with speech delay.

Perceptual consequences of "hidden" hearing loss.

Dramatic results from recent animal experiments show that noise exposure can cause a selective loss of high-threshold auditory nerve fibers without affecting absolute sensitivity permanently. This cochlear neuropathy has been described as hidden hearing loss, as it is not thought to be detectable using standard measures of audiometric threshold. It is possible that hidden hearing loss is a common condition in humans and may underlie some of the perceptual deficits experienced by people with clinically normal hearing. There is some evidence that a history of noise exposure is associated with difficulties in speech discrimination and temporal processing, even in the absence of any audiometric loss. There is also evidence that the tinnitus experienced by listeners with clinically normal hearing is associated with cochlear neuropathy, as measured using Wave I of the auditory brainstem response. To date, however, there has been no direct link made between noise exposure, cochlear neuropathy, and perceptual difficulties. Animal experiments also reveal that the aging process itself, in the absence of significant noise exposure, is associated with loss of auditory nerve fibers. Evidence from human temporal bone studies and auditory brainstem response measures suggests that this form of hidden loss is common in humans and may have perceptual consequences, in particular, regarding the coding of the temporal aspects of sounds. Hidden hearing loss is potentially a major health issue, and investigations are ongoing to identify the causes and consequences of this troubling condition.

Cochlear implantations in young children with cochlear nerve deficiency diagnosed by MRI.

OBJECTIVE: To investigate postoperative outcomes after cochlear implantation in young children with cochlear nerve deficiency and compare the results with those of cochlear implantation in patients with normal cochlear nerve. STUDY DESIGN: Historical cohort study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Six children under the age of 36 months with cochlear nerve deficiency, as determined by magnetic resonance imaging (MRI), received cochlear implantation between July 2006 and March 2008. Fifteen children under the age of 36 months with normal cochlear nerve in the implanted ear underwent cochlear implantation during the same period and were selected as the control group. Medical records, imaging studies, and speech evaluations were reviewed. RESULTS: Our study group scored lower in the Infant-Toddler Meaningful Auditory Integration Scale compared to the control group. Our study group produced categories of auditory performance scores not less than 4 except for one patient. Speech intelligibility rating scores in the control group gradually increased after cochlear implantation, but for the study group, the score remained zero 12 months after the implantation. In open-set one-syllable tests, five patients with cochlear nerve deficiency showed no response at the latest follow-up, whereas patient 6 began to show delayed improvement after 18 months. The results of the open-set two-syllable test were similar to those of the open-set one-syllable test. CONCLUSION: Young children with nonvisualized cochlear nerve on MRI showed worse outcomes compared to the children with normal cochlear nerve. Cochlear nerve deficiency on MRI is a marker of very poor outcome with cochlear implantations.

Modulation detection by patients with eighth-nerve tumors.

Detection thresholds for sinusoidally amplitude-modulated broad-band noise were measured as a function of modulation frequency for 4 normally hearing listeners and for 6 patients suffering eighth-nerve tumors. Measurements were obtained using a method-of-adjustment (MOA) procedure. On average, the threshold values revealed that more modulation was needed across all modulation frequencies for the patients' affected ears relative to either the normally hearing listeners or the patients' better ears. The cutoff frequency derived from the average modulation-threshhold function (MTF) for the affected ears was about half the normal value. For a simple lowpass-filter model of the process, the latter result suggested a doubling of the auditory time constant in the affected ears. These patients, on average, exhibited the characteristic high-frequency audiometric hearing loss most often associated with eighth-nerve tumors. Their MTFs closely resembled MTFs described previously for high-frequency audiometric hearing loss. The results of statistical analyses suggested that high frequency audiometric hearing loss, irrespective of other influences, is the most parsimonious explanation for the increased modulation thresholds measured for the eighth-nerve tumor patients.

Déficit funcional en la capacidad auditiva de oyentes con trastorno de neuropatía auditiva / Functional hearing deficits in listeners with auditory neuropathy spectrum disorder

El trastorno de neuropatía auditiva (ANSD) es un tipo de disfunción auditiva en la que los procesos periféricos pueden ser normales, pero la transmisión neural a través del par craneal VIII y el tronco encefálico auditivo está perturbada. Las consecuencias perceptivas del ANSD difieren de las pérdidas auditivas cocleares y, por lo general, incluyen distorsión de las claves temporales (sincronización) y discriminación de frecuencias alterada. Estos déficit básicos de procesamiento pueden, a su vez, afectar a la audición funcional, lo que da lugar a deficiencias graves en la percepción del habla, sobre todo en la presencia de ruido de fondo. Este artículo abordará los mecanismos subyacentes en el ANSD, ilustrará sus efectos mediante un detallado estudio de caso y presentará pruebas sobre el uso de un sistema FM personal en un oyente afectado (AU)

Auditory neuropathy spectrum disorder (ANSD) is a form of auditory dysfunction in which peripheral processes can be normal, but neural transmission through the VIIIth nerve and auditory brainstem is disrupted. The perceptual consequences of ANSD are distinct from those of cochlear hearing loss and most commonly include distortion of temporal (timing) cues and altered frequency discrimination. These basic processing deficits can, in turn, affect functional hearing, resulting in severe impairment of speech perception particularly in the presence of background noise. This article will address the mechanisms underlying ANSD, illustrate it's effects in a detailed case study and show evidence for the use of personal FM devices in affected listeners (AU)