Auditory neuropathy in a patient exposed to xylene: case report

Objective: To report the case of an adult patient who developed auditory complaints following xylene exposure, and to review the literature on the effects of solvent exposure on hearing.Case report: The patient presented with a gradual deterioration in his ability to hear in difficult acoustic environments and also to hear complex sounds such as music, over a 40-year period. His symptoms began following exposure to the solvent xylene, and in the absence of any other risk factor. Our audiological investigations revealed normal otoacoustic emissions with absent auditory brainstem responses and absent acoustic reflexes in both ears, consistent with a diagnosis of bilateral auditory neuropathy. Central test results were also abnormal, indicating possible involvement of the central auditory pathway.Conclusions: To our knowledge, this is the first report of retrocochlear hearing loss following xylene exposure. The test results may provide some insight into the effect of xylene as an isolated agent on the human auditory pathway

Useful residual hearing despite radiological findings suggestive of anacusis

A severe malformation of the inner ear, often referred to as severe labyrinthine dysplasia or common cavity deformity, consists of an absent or dilated cochlear basal coil, wide communication with the vestibule and a tapered internal acoustic meatus and can be associated with absent hearing. We discuss two children with severe labyrinthine dysplasia as shown by computed tomography (CT) scans and, in the first case, an absent VIIIth nerve bilaterally shown by magnetic resonance imaging (MRT). In 1995, both cases were precluded from cochlear implantation, on the basis of the absent VIIIth nerve (first case) and increased risk of CSF leak during operation (second case). However, audiometric results and vocalization patterns of both children suggested the presence of some residual hearing function, while recently reported specific surgical techniques have been found to be safe and effective in the cochlear implantation of the common cavity deformity. The management of such cases should be decided on the grounds of a full audiological assessment in conjunction with the radiological features, in the light of current surgical trends shown to be safe and effective

Auditory Training Effects on the Listening Skills of Children With Auditory Processing Disorder

OBJECTIVES: Children with auditory processing disorder (APD) typically present with "listening difficulties,"' including problems understanding speech in noisy environments. The authors examined, in a group of such children, whether a 12-week computer-based auditory training program with speech material improved the perception of speech-in-noise test performance, and functional listening skills as assessed by parental and teacher listening and communication questionnaires. The authors hypothesized that after the intervention, (1) trained children would show greater improvements in speech-in-noise perception than untrained controls; (2) this improvement would correlate with improvements in observer-rated behaviors; and (3) the improvement would be maintained for at least 3 months after the end of training. DESIGN: This was a prospective randomized controlled trial of 39 children with normal nonverbal intelligence, ages 7 to 11 years, all diagnosed with APD. This diagnosis required a normal pure-tone audiogram and deficits in at least two clinical auditory processing tests. The APD children were randomly assigned to (1) a control group that received only the current standard treatment for children diagnosed with APD, employing various listening/educational strategies at school (N = 19); or (2) an intervention group that undertook a 3-month 5-day/week computer-based auditory training program at home, consisting of a wide variety of speech-based listening tasks with competing sounds, in addition to the current standard treatment. All 39 children were assessed for language and cognitive skills at baseline and on three outcome measures at baseline and immediate postintervention. Outcome measures were repeated 3 months postintervention in the intervention group only, to assess the sustainability of treatment effects. The outcome measures were (1) the mean speech reception threshold obtained from the four subtests of the listening in specialized noise test that assesses sentence perception in various configurations of masking speech, and in which the target speakers and test materials were unrelated to the training materials; (2) the Children's Auditory Performance Scale that assesses listening skills, completed by the children's teachers; and (3) the Clinical Evaluation of Language Fundamental-4 pragmatic profile that assesses pragmatic language use, completed by parents. RESULTS: All outcome measures significantly improved at immediate postintervention in the intervention group only, with effect sizes ranging from 0.76 to 1.7. Improvements in speech-in-noise performance correlated with improved scores in the Children's Auditory Performance Scale questionnaire in the trained group only. Baseline language and cognitive assessments did not predict better training outcome. Improvements in speech-in-noise performance were sustained 3 months postintervention. CONCLUSIONS: Broad speech-based auditory training led to improved auditory processing skills as reflected in speech-in-noise test performance and in better functional listening in real life. The observed correlation between improved functional listening with improved speech-in-noise perception in the trained group suggests that improved listening was a direct generalization of the auditory training

Effect of cochlear implant electrode insertion on middle-ear function as measured by intra-operative laser Doppler vibrometry

Hypothesis: The aim of this study was to investigate the impact of cochlear implant electrode insertion on middle-ear low frequency function in humans.Background: Preservation of residual low frequency hearing with addition of electrical speech processing can improve the speech perception abilities and hearing in noise of cochlear implant users. Preservation of low frequency hearing requires an intact middle-ear conductive mechanism in addition to intact inner-ear mechanisms. Little is known about the effect of a cochlear implant electrode on middle-ear function.Methods: Stapes displacement was measured in seven patients undergoing cochlear implantation. Measurements were carried out intra-operatively before and after electrode insertion. Each patient acted as his or her own control. Sound was delivered into the external auditory canal via a speaker and calibrated via a probe microphone. The speaker and probe microphone were integrated into an individually custom-made ear mould. Ossicular displacement in response to a multisine stimulus at 80 dB SPL was measured at the incudostapedial joint via the posterior tympanotomy, using an operating microscope mounted laser Doppler vibrometry system.Results: Insertion of a cochlear implant electrode into the scala tympani had a variable effect on stapes displacement. In three patients, there was little change in stapes displacement following electrode insertion. In two patients, there was a significant increase, while in a further two there was a significant reduction in stapes displacement. This variability may reflect alteration of cochlear impedance, possibly due to differing loss of perilymph associated with the electrode insertion.Conclusion: Insertion of a cochlear implant electrode produces a change in stapes displacement at low frequencies, which may have an effect on residual low frequency hearing thresholds

Lack of Association between Audiogram and Hearing Disability Measures in Mild Cognitive Impairment and Dementia: What Audiogram Does Not Tell You

(1) Introduction: The validity of self-reported hearing disability measures has been assessed using their correlation with the pure-tone average (PTA) hearing loss for non-cognitively impaired adults. However, for people with cognitive impairment, factors in addition to the PTA can play a role in their self-reported difficulties. Patients with cognitive impairment may experience more hearing difficulties due to their brain processing sounds abnormally, irrespective of PTA. (2) Methods: Three groups of hearing aid users who had normal cognition, mild cognitive impairment and dementia were recruited. Self-reported hearing abilities were assessed with the modified Amsterdam inventory for auditory disability (mAIAD) and the speech, spatial and qualities of hearing scale (SSQ). (3) Results: The SSQ and mAIAD scores were highly correlated with each other for all three groups. However, a correlation with objective PTA was found in the normal cognition but not the cognitively impaired groups. Self-reported hearing scores were associated with cognitive scores for the dementia group (4) Discussion: In people with combined cognitive and hearing impairment, PTA alone may be a poor predictor of hearing abilities. Subjective hearing questionnaires together with hearing tests may provide a better understanding of their hearing difficulties

Experiences of Patients With Auditory Processing Disorder in Getting Support in Health, Education, and Work Settings: Findings From an Online Survey

OBJECTIVE: To explore the views and experiences of individuals with Auditory Processing Disorder (APD) and/or their families in getting support from services and to receive their suggestions for improvement. DESIGN: Cross-sectional random sample survey with descriptive analysis. SETTINGS: Online survey. PARTICIPANTS: One hundred and fifty six individuals with APD and/or their family members from the APD Support UK patient support organization and four associated APD Facebook groups. MAIN OUTCOME MEASURE: A 16-item questionnaire on negative and positive experiences in getting a referral for diagnosis, funding for the FM system, and overall support for APD. RESULTS: The key findings that emerged included reports of difficulty in getting a referral for diagnosis (54%), obtaining funding for an FM system (45%), getting support for APD (61%), and poor recognition and awareness of APD (63%) in Education, Health or Work settings. The positive experiences reported were ease in getting a referral for diagnosis (46%), in obtaining an FM system (20%), and with diagnosis leading to help at school or to a better understanding of the condition and the required adjustments. The recommended improvement areas were raising awareness of APD and related management in Education (30%), the Health sector (25%), and the public (18%). CONCLUSIONS: Individuals and families of individuals with APD overwhelmingly report a lack of awareness of APD across health, education, and work sectors, and difficulties in getting access to diagnosis and support. This information may provide an initial understanding of the patients' needs for clinical services for APD, identify research priorities, and influence longer-term public health decisions toward improved care

Auditory Processing Performance of the Middle-Aged and Elderly: Auditory or Cognitive Decline?

BACKGROUND: Despite the well-established relationship between aging and auditory processing decline, identifying the extent to which age effect is the main factor on auditory processing performance remains a great challenge due to the co-occurrence of age-related hearing loss and age-related cognitive decline as potential confounding factors. PURPOSE: To investigate the effects of age-related hearing loss and working memory on the clinical evaluation of auditory processing of middle-aged and elderly. RESEARCH DESIGN: Cross-sectional study. STUDY SAMPLE: A total of 77 adults between 50 and 70 yr of age were invited to participate in the study. DATA COLLECTION AND ANALYSIS: The participants were recruited from a larger study that focused on the assessment and management of sensory and cognitive skills in elderly participants. Only participants with normal hearing or mild-to-moderate age-related hearing loss, with no evidence of cognitive, psychological, or neurological conditions were included. Speech-in-noise, dichotic digit, and frequency pattern tests were conducted as well as a working memory test. The hearing loss effect was investigated using an audibility index, calculated from the audiometric threshold. The performance on the digit span test was used to investigate working memory effects. Both hearing loss and working memory effects were investigated via correlation and regression analyses, partialling out age effects. The significance level was set at p < 0.05. RESULTS: The results demonstrated that, while hearing loss was associated to the speech-in-noise performance, working memory was associated to the frequency pattern and dichotic digit performances. Regression analyses confirmed the relative contribution of hearing loss to the variance in speech-in-noise and working memory test to the variance in frequency pattern and dichotic digit test performance. CONCLUSIONS: The performance decline of the elderly in auditory processing tests may be partially attributable to the working memory performance and, consequently, to the cognitive decline exhibited by this population. Mild-to-moderate hearing loss seems to affect performance on specific auditory processing tasks, such as speech in noise, reinforcing the idea that auditory processing disorder in the elderly might also be associated to auditory peripheral deficits

The Screening Accuracy of a Visually Based Montreal Cognitive Assessment Tool for Older Adult Hearing Aid Users

OBJECTIVES: This research aims to validate a modified visually based Montreal Cognitive Assessment for hearing-aid users (MoCA-HA). This population should be the target of cognitive screening due to high risk of developing dementia. DESIGN: Case-control study. SETTING: The participants were recruited from referral hearing-aid center and memory clinic in central London, United Kingdom. PARTICIPANT: 75 hearing-aid users were recruited. Of these, thirty were cognitively intact controls with hearing impairment (NC-HI); thirty had mild cognitive impairment with hearing impairment (MCI-HI); fifteen had dementia with hearing impairment (D-HI). MEASUREMENTS: The baseline characteristics and analysis of the MoCA-HA for the NC-HI were recorded. The MoCA-HA performance of the MCI-HI cohort and D-HI cohort were also studied. RESULTS: The cutpoint of <26 yields 93.3% sensitivity with 80% specificity in distinguishing MCI-HI from NC-HI. The specificity increased to 95.6% in screening for all cognitive impairment (MCI-HI and D-HI) from NC-HI. CONCLUSION: The MoCA-HA has been validated with a cutpoint which is comparable to the traditional MoCA. This tool may help clinicians to early identify older adult hearing-aid users for appropriate cognitive evaluation