Monthly Archives: September 2008

Causes of childhood deafness in Pukhtoonkhwa Province of Pakistan and the role of consanguinity

from the Journal of Laryngology and Otology

Background: Deafness is the hidden disability of childhood, and leads to poor educational and employment prospects. There is little published information on deafness in Pakistan. Profound hearing impairment is more prevalent in countries where consanguineous marriages are common, such as Pakistan. This study aimed to assess causes of childhood deafness and association with parental consanguinity, within deaf and hearing children in the Peshawar district of Pukhtoonkhwa Province, Pakistan.

Methods: One hundred and forty deaf children were identified from two schools for deaf children within the Peshawar district. These children were assessed via audiology, otoscopic examination, case note review and parental history, in order to attempt to ascertain the cause of their deafness. Two hundred and twenty-one attendees at a local immunisation clinic (taken as representative of the local childhood population) were also screened for hearing impairment. Parents of both groups of children were assessed by interview and questionnaire in order to ascertain the mother and father’s family relationship (i.e. whether cousins or unrelated).

Results: Of the 140 deaf school pupils, 92.1 per cent were profoundly hearing impaired and 7.9 per cent were severely hearing impaired. All these children had bilateral sensorineural hearing loss. A possible cause of deafness was identified in only six of these children. Parental consanguinity (i.e. first or second cousins) was established for 86.4 per cent of deaf school pupils and 59.7 per cent of immunisation clinic attendees. None of the control children were identified as having a hearing problem.

Conclusion: The prevalence of parental consanguinity was significantly higher in deaf children compared with non-hearing impaired children. However, the study also confirmed a high rate of consanguinity within the general Peshawar community. In this setting, prevention of consanguineous unions is the only means of reducing levels of congenital hearing impairment. The current levels of hearing disability represent both a prominent public health problem and an important, potentially preventable childhood disability.

Hearing aids and tinnitus therapy: a 25-year experience

from the Journal of Laryngology and Otology

Objectives: (1) To assess the subjective tinnitus perception of patients with audiologically proven hearing loss presenting to a tinnitus clinic, both before and after hearing aid provision; (2) to investigate subjective tinnitus perception in patients with unilateral and bilateral hearing loss; and (3) to assess the impact on tinnitus perception, if any, of a digital hearing aid programme in patients provided with hearing aids.

Design: Prospective data collection for patients attending a tinnitus clinic over a 25-year period (1980–2004).

Setting: University teaching hospital otolaryngology department.

Participants: A total of 2153 consecutive patients attending a consultant-delivered specialist tinnitus clinic.

Main outcomes measures: A visual analogue scale was used to assess the degree of tinnitus perception improvement, if any, comparing before versus after unilateral or bilateral aiding (in those with audiometrically proven hearing loss). A further assessment compared the effect of digital hearing aid programme introduction on symptomatic tinnitus perception in patients provided with unilateral or bilateral aids.

Results: A total of 1440 patients were given hearing aids (826 unilateral and 614 bilateral). There was little difference in tinnitus perception, comparing overall aiding results in unilaterally or bilaterally aided patients. Overall, 554 (67 per cent) of unilaterally aided patients and 424 (69 per cent) of bilaterally aided patients reported some improvement in their tinnitus perception following aiding. There was a statistically significant improvement in tinnitus perception, comparing analogue aids with digital hearing aids, following introduction of a digital hearing aid programme in 2000, in both unilaterally (p < 0.001) and bilaterally (p < 0.001) aided patients.

Conclusions: Provision of hearing aids in patients with audiometrically demonstrable hearing loss can play a very important part in tinnitus control. The additional improvement in tinnitus control observed following introduction of programmable digital aids had a summative effect in the management of these patients.

Charity Issues MP3 Top Tips To Prevent Deafness

from Medical News Today.com

Deafness Research UK has published its top tips for the safe use of MP3 players, following research by the charity that shows too many people are putting their hearing at risk by listening to MP3 players too loudly for too long.

Trouble With Your Ears? You’re Not Alone, And Help Is At Hand From Leading National Charity. UK

from Medical News Today.com

Help is at hand for the many thousands each year who suffer painful and debilitating ear complaints, many of which are avoidable with better ear hygiene and prompt medical attention, according to Deafness Research UK who have recently published a handy leaflet called ‘Trouble With Your Ears?’

Ear Breakthrough Gives Hope To Millions Of Deaf And Hard Of Hearing People

from Medical News Today.com

The latest research, conducted by Dr Jörg T. Albert, a Deafness Research UK research fellow at the UCL Ear Institute, together with scientists at the University of Cologne, shows that fruit flies have ears which mechanically amplify sound signals in a remarkably similar way to the sensory cells found in the inner ear of vertebrates including humans. The finding means that the wealth of genetic techniques already available to study the fruit fly can now be used to target how the ear works.

Steroid treatment of hearing loss in enlarged vestibular aqueduct anomaly

from the International Journal of Pediatric Otorhinolaryngology

Objective
1. Determine whether corticosteroid therapy improves hearing thresholds of patients with enlarged vestibular aqueduct (EVA) anomaly. 2. Determine sample size for a future prospective study.

Methods
Retrospective chart review hearing loss in EVA patients comparing patients treated with corticosteroids and untreated patients.

Results
Eighty percent (n = 5) of patients treated with steroids for hearing loss demonstrated audiometric improvement, compared to 14.3% of patients (n = 7) not treated. The pure tone average improved by 17.7 dB in the steroid treated group. A prospective, placebo-controlled trial would need between 19 and 45 patients in each group, treatment versus no-treatment, to achieve statistical significance.

Conclusion
Patients with EVA who develop hearing loss have a high rate of hearing improvement when treated with corticosteroid therapy. The hearing improvement appears to be better than spontaneous recovery.

Twenty years of audiology in a patient with Norrie disease

from the International Journal of Pediatric Otorhinolaryngology

Objective
To describe disease progression and treatment outcomes over a 20-year period (ages 5–25) in a young man with Norrie disease (occuloacousticocerebral dysplasia), ND; OMIM #310600. Affected individuals are born blind and develop progressive sensory loss with onset in adolescence. This disease is X-linked and has been associated with mutations of the NDP gene (Xp11.4).

Methods
The patient was followed using repeated audiograms, as well as reports of educational progress and hearing aid use. The specific mutation was found by molecular analysis.

Results
The patient demonstrated progressive sensory loss with good preservation of word recognition. The loss was initially high frequency and asymmetric in adolescence and became more severe, more symmetric and affected practically all frequencies by the end of childhood. Educational progress was affected by the cognitive effects of the syndrome, and hearing aid use was very effective.

Conclusions
A bilateral progressive sensory loss with good preservation of word recognition was documented in detail. The residual word recognition supported good use of hearing aids in this case.

Grading the First Presidential Debate

fromWebMD.com

Experts Analyze Body Language and Speech Patterns in the First Debate

Dyslexic participants show intact spontaneous categorization processes

from Dyslexia

We examine the performance of dyslexic participants on an unsupervised categorization task against that of matched non-dyslexic control participants. Unsupervised categorization is a cognitive process critical for conceptual development. Existing research in dyslexia has emphasized perceptual tasks and supervised categorization tasks (for which intact attentional processes are paramount), but there have been no studies on unsupervised categorization. Our investigation was based on Pothos and Chater’s (Cognit. Sci., 2002; 26: 303-343) model of unsupervised categorization and the corresponding methodology for analysing results. Across all performance indices and various data-processing options, we could identify no difference between dyslexic and non-dyslexic participants. Copyright © 2008 John Wiley & Sons, Ltd.

Early home-based intervention in the Netherlands for children at familial risk of dyslexia

from Dyslexia

Dutch children at higher familial risk of reading disability received a home-based intervention programme before formal reading instruction started to investigate whether this would reduce the risk of dyslexia. The experimental group (n=23) received a specific training in phoneme awareness and letter knowledge. A control group (n=25) received a non-specific training in morphology, syntax, and vocabulary. Both interventions were designed to take 10 min a day, 5 days a week for 10 weeks. Most parents were sufficiently able to work with the programme properly. At post-test the experimental group had gained more on phoneme awareness than the control group. The control group gained more on one of the morphology measures. On average, these specific training results did not lead to significant group differences in first-grade reading and spelling measures. However, fewer experimental children scored below 10th percentile on word recognition. Copyright © 2008 John Wiley & Sons, Ltd.

Neural tonotopy in cochlear implants: an evaluation in unilateral cochlear implant patients with unilateral deafness and tinnitus

from Hearing Research

Article in press. No abstract available.

Brainstem encoding of voiced consonant–vowel stop syllables

from Clinical Neurophysiology

Objective
The purpose of this study is to expand our understanding of how the human auditory brainstem encodes temporal and spectral acoustic cues in voiced stop consonant–vowel syllables.
Methods
Auditory evoked potentials measuring activity from the brainstem of 22 normal learning children were recorded to the voiced stop consonant syllables [ga], [da], and [ba]. Spectrotemporal information distinguishing these voiced consonant–vowel syllables is contained within the first few milliseconds of the burst and the formant transition to the vowel. Responses were compared across stimuli with respect to their temporal and spectral content.
Results
Brainstem response latencies change in a predictable manner in response to systematic alterations in a speech syllable indicating that the distinguishing acoustic cues are represented by neural response timing (synchrony). Spectral analyses of the responses show frequency distribution differences across stimuli (some of which appear to represent acoustic characteristics created by difference tones of the stimulus formants) indicating that neural phase-locking is also important for encoding these acoustic elements.
Conclusions
Considered within the context of existing knowledge of brainstem encoding of speech–sound structure, these data are the beginning of a comprehensive delineation of how the human auditory brainstem encodes perceptually critical features of speech.
Significance
The results of this study could be used to determine how neural encoding is disrupted in the clinical populations for whom stop consonants pose particular perceptual challenges (e.g., hearing impaired individuals and poor readers).

Advances in pediatric audiological and vestibular disorders

from the International Journal of Audiology

This Article does not have an abstract.

Current considerations in pediatric speech audiometry

from the International Journal of Audiology

Abstract
Current considerations in pediatric speech perception assessment are highlighted in this article with a focus on specific test principles and variables that must be addressed when evaluating speech perception performance in children. Existing test materials are reviewed with an emphasis on the level of sensitivity and standardization that they have for accurate assessment of a child’s speech perception performance. A test battery approach is advocated because speech perception is an abstract construct, and in order to provide a comprehensive assessment of a child’s capabilities, information is needed from several sources of concrete data. The importance of ongoing speech perception assessment in children is also emphasized because a child’s progress over time must be monitored to determine if improvements need to be made with amplification and intervention efforts. Results from pediatric speech perception assessments can provide practical information regarding the prognosis of speech, language, reading, and cognitive abilities of children as well as steps that need to be taken in the intervention process.

It all sounds the same to me: sequential ERP and behavioral effects during pitch and harmonicity judgments

from Cognitive, Affective, & Behavioral Neuroscience

The representation of complex sounds was examined by comparing both behavioral and event-related brain potentials (ERPs) to the change or repetition of fundamental frequency (f0) and harmonicity. In the pitch task, participants were asked to categorize the incoming stimulus as either low or high, regardless of harmonicity, and in the harmonicity task, participants indicated whether the stimulus was tuned or mistuned, regardless of pitch. Over three experiments, participants were faster in responding to pitch than to harmonicity. As a result of this asymmetry, behavioral and ERP data showed that irrelevant changes in harmonicity had little impact on performance during the pitch task, whereas harmonicity judgments were impeded by irrelevant changes in f0. These data are consistent with both general horse-race accounts of processing and specific accounts of mistuning detection that posit prior f0 registration. In addition, ERP components N2 and P3 were modulated by both intertrial contingency and task instructions, revealing the further influence of top-down mechanisms on concurrent sound segregation.