British journal of audiology最新文献

Over 45 genes that cause autosomal non-syndromic hearing impairment (NSHI) have been localized and many more are predicted to exist. To clone these genes, a number of different strategies can be used. This paper focuses on four general approaches: functional cloning, positional cloning, position-dependent candidate gene cloning, and position-independent candidate gene cloning.

The identification of genes leading to hereditary hearing impairment is one of the ways to elucidate the functioning of the inner ear. Over the past few years, several genes responsible for non-syndromal hereditary hearing impairment have been identified. One of these genes, named COCH, is responsible for autosomal dominant progressive sensorineural hearing loss associated with vestibular impairment (DFNA9). Histopathological analysis in patients with a COCH mutation revealed the presence of an acidophylic mucopolysaccharide deposit in the inner ear. An overview of the clinical, pathological and genetic studies on COCH is given, and the possible role of COCH in the pathology of DFNA9 is discussed.

The management of a child with congenital ear malformation, in particular if the external ear is severely involved, is difficult because of the complexity of the therapeutic problem, and that of parental anxiety. It is very important to plan a complete therapeutic/habilitative programme as soon as possible, even if surgical procedures are delayed. Diagnostic imaging plays an important role in the global assessment of a child with microtia, in order to diagnose possible associated external auditory canal, middle and inner ear malformations. For these reasons our diagnostic protocol for children with microtia includes otological and audiological evaluation, clinical genetics and radiological imaging, from the neonatal period. Here, data are reported on 27 children with microtia who completed the diagnostic protocol. In eight of 27 cases microtia was bilateral: in unilateral cases the right side was affected more frequently. Other congenital malformations were diagnosed in 41% of cases. A high correlation between the degree of microtia and the frequency of external and middle ear dysplasias was found, in accordance with larger studies of the literature. Inner ear malformations were found less frequently, but without apparent correlation with the degree of microtia. The fact that children with microtia may also have severe inner ear malformations is emphasized.

Meta-analysis is a technique of combining results from different trials in order to obtain estimates of effects across studies. Meta-analysis has, as yet, rarely been used in audiological research. The aim of this paper was to conduct a meta-analysis on psychological treatment of tinnitus. The outcomes of 18 studies, including a total of 24 samples and up to 700 subjects, were included and coded. Included were studies on cognitive/cognitive-behavioural treatment, relaxation, hypnosis, biofeedback, educational sessions and problem-solving. Effect sizes for perceived tinnitus loudness, annoyance, negative affect (e.g. depression) and sleep problems were calculated for randomized controlled studies, pre-post-treatment design studies and follow-up results. Results showed strong to moderate effects on tinnitus annoyance for controlled studies (d = 0.86), pre-post designs (d = 0.5) and at follow-up (d = 0.48). Results on tinnitus loudness were weaker and disappeared at follow-up. Lower effect sizes were also obtained for measures of negative affect and sleep problems. Exploratory analyses revealed that cognitive-behavioural treatments were more effective on ratings of annoyance in the controlled studies. It is concluded that psychological treatment for tinnitus is effective, but that aspects such as depression and sleep problems may need to be targeted in future studies.

A follow-up study has been performed on 29 of 33 original subjects who participated in a clinical trial of the digital hearing aid Oticon DigiFocus. The follow-up was performed after one year's use. Use of hearing instruments was assessed and questionnaires on hearing aid benefit, and hearing impairment and handicap were administered. Ratings of sound quality and measurements of speech recognition in noise were also performed. The results indicated almost doubled daily use of hearing aids as compared to that stated for the subjects' previous analogue aids one year earlier. Further, we found statistically significant improvements in speech recognition in noise one year post-fitting as compared to after one month. Other test results were essentially unchanged over time: no measure showed a significantly poorer rating or performance.

One of the many reported advantages of the insert earphone over the supra-aural earphone is increased inter-aural attenuation (IA). Minimum values of IA determine the need for masking of the non-test ear in air-conduction audiometry. The aim of the present study was to measure inter-aural attenuation for the Etymotic Research ER-3A insert earphone (with deep and shallow insertion of the ear plug within the ear canal) and compare this with the supra-aural Telephonics TDH-39/MX41-AR earphone/cushion combination. Subjects were 18 adults ranging in age from 38 to 68 years (mean 50 years). Each subject had no hearing in one ear following translabyrinthine surgery for removal of an acoustic neuroma. The opposite ear had hearing thresholds better than 40 dB HL and an air-bone gap of less than 10 dB at any audiometric frequency. Pure tone air-conduction thresholds were obtained in the range 0.25-8 kHz. Deep insertion of the insert earphone was deemed to occur when the outside edge of the ear plug was flush with the entrance of the ear canal. Shallow insertion was deemed to occur when half of the ear plug (6 mm) was inside the entrance of the ear canal. IA was defined operationally as the difference between the good-ear and poor-ear not-masked air conduction threshold for a given audiometric frequency and earphone. The results show that the TDH-39/MX41-AR combination provides a median IA of approximately 60 dB with a lower limit of approximately 45 dB. Greater IA was obtained with the ER-3A insert earphone but this depended on the depth of insertion. With a deep insertion, the 1A values were some 15-20 dB greater than with the supra-aural earphone. Although frequency-specific IA values are provided, a simple rule of thumb is to apply masking to the non-test ear when the pure tone airconduction signal from the ER-3A insert earphone exceeds the bone conduction threshold of the non-test ear by 55 dB HL or more. If it is not possible to obtain a deep insertion depth this value should be reduced by 5 dB.

Tympanometry provides a rapid, non-invasive and objective assessment of middle ear (ME) status and is widely used for the clinical diagnosis and follow-up of otitis media with effusion (OME). ME pressure, acoustic admittance and tympanometric gradient are the main test parameters used in making assignments to diagnostic classes (i.e. presence or absence of effusion, effusion quantity). Of these, the tympanometric gradient was suggested to be more sensitive to the presence of effusion, but this has not been demonstrated conclusively and no standard definition of that gradient is accepted. In this study, 10 cynomolgus monkeys with experimental OME were used to compare the diagnosis of OME made using three different methods to estimate tympanometric gradient with that provided by simultaneous magnetic resonance imaging (MRI) of the ME. All three methods of tympanometric gradient measurement were highly correlated with the quantity of ME effusion measured by the MRI. Although not significant, the MRI results were better correlated with those for the 'width' method when compared to either the 'difference' or the 'ratio' method of gradient estimation. This study demonstrates the use of MRI as a gold standard for evaluating the accuracy of other methods to diagnose ME effusion.

A model for predicting loudness for people with cochlear hearing loss is applied to the problem of the initial fitting of multi-channel fast-acting compression hearing aids. The fitting is based entirely on the pure tone audiogram, and does not require measures of loudness growth. One constraint is always applied: the specific loudness pattern evoked by speech of a moderate level (65 dB SPL) should be reasonably flat (equal loudness per critical band), and the overall loudness should be similar to that evoked in a normal listener by 65-dB speech. This is achieved using the 'Cambridge' formula. For hearing aids where the compression threshold in each channel can be set to a very low value, an additional constraint is used: speech with an overall level of 45 dB SPL should be audible over its entire dynamic range in all frequency channels from 500 Hz up to about 4 kHz. For hearing aids where the compression thresholds cannot be set to very low values, a different additional constraint is used: the specific loudness pattern evoked by speech of a high level (85 dB SPL, and with the spectral characteristics of shouted speech) should be reasonably flat, and the overall loudness should be similar to that evoked in a normal listener by 85-dB speech. For both cases, compression ratios are limited to values below 3. For each of these two cases, we show how to derive compression ratios and gains, and for the first case, compression thresholds, for each channel. The derivations apply to systems with any number of channels. A computer program implementing the derivations is described. The program also calculates target insertion gains at the centre frequency of each channel for input levels of 50, 65 and 80 dB SPL, and target gains at the eardrum measured relative to the level at the reference microphone of a probe microphone system.

Popular concern about widespread damage to the hearing from exposure to amplified music continues, although there has been little firm evidence of permanent effects in casual listeners. Measurement of transient evoked otoacoustic emissions (TEOAEs) provides a sensitive technique for testing outer hair cell (OHC) function, and was used in this study of 28 young adults aged 18-25 years, whose only significant source of noise exposure was loud music, to look for evidence of poorer cochlear function in those of greater exposure; they provided 27 right ears and 27 left ears suitable for measurement of TEOAE strength. Estimates of subjects' total noise dose were obtained from self-reports of the duration and intensity of their exposure to music and other sources of noise. Ears with greater exposure to loud music showed significantly weaker TEOAEs than less exposed ears in response to a 4 kHz tone burst, or in response to a saturating (82 dBSPL) click if the response was treated with a high-frequency bandpass filter (2-4 kHz) (p<0.05). Differences between more exposed and less exposed groups of ears were most marked in the 2 kHz half-octave band for right ears, and in the 2.8 kHz half-octave band for left ears. A hypothesis is proposed that weakness in TEOAEs as a result of exposure to loud music is seen first in the 2 kHz region of the emission spectrum, and later at higher frequencies; and that for a given amount of exposure, TEOAE weakness (or OHC damage) is more advanced in left ears than in right.