Audiology : official organ of the International Society of Audiology最新文献

A study of 56 severely asphyxiated infants (8 hearing impaired and 46 normally hearing) was designed to identify specific markers associated with asphyxia which could be related to hearing loss. Sixteen variables, including such items as: one- and five-minute Apgar scores, muscle tone, use of a ventilator, prolonged stay in the NICU, hypoxic-ischemic encephalopathy (HIE), other organ damage, and intra-uterine growth retardation (IUGR) were considered. Results suggested four factors related to asphyxia which are often found in the presence of hearing loss, but none of these was considered a definitive marker or predictor of such a disability. A combination of HIE, seizures, associated organ damage and IUGR should be considered a strong marker for the probability of a sensorineural hearing loss.

The aim of this study was to assess the value of repeated audiometric screens offered to elderly in general practice. In 1991, an audiometric screen was performed on 660 participants, aged 60 years and over, enlisted in one general practice near Rotterdam, the Netherlands. We repeated the audiometric screen 5 years later in 80.2% (405/505) of the eligible participants of the first screen. After the first screen, 24.3% of those who were hearing impaired had discussed this with their general practitioner, 21.5% were referred to a specialist in otolaryngology and 12.1% had been prescribed a hearing aid. The effect of the repeated screen was lower as only 7.3% of the hearing impaired participants received a hearing aid. Efforts to screen on hearing loss will be fruitless and can best be avoided by general practitioners unless strategies are developed to increase the use of hearing aids after a positive screening result.

A study of self-assessed hearing problems was performed comprising 48,680 Swedish inhabitants aged 16-84 years. The participants of the survey responded to personal interviews during the period 1986-1993. One of the questions in the interview concerned difficulties of hearing in background noise. The total prevalence of the reported hearing problems was 10.7 per cent, varying from 2.4 per cent in the youngest age group to 30 per cent in the oldest. Men reported difficulties in hearing more often than women, except in the youngest age group. Hearing problems were more often reported by manual workers, unemployed and by those who had taken early retirement, than by non-manual employees and the self-employed. Regional differences regarding hearing problems were observed. The prevalence of self-reported problems was lowest in metropolitan Stockholm (7.9 per cent) and increased in the following order: other major cities (9.4 per cent), other cities (10.5 per cent), small population centres (12.5 per cent), agricultural areas (13.5 per cent) and sparsely populated forest areas (15 per cent). In summary, a number of factors related to ageing, socioeconomic status and domicile were related to self-assessed difficulties hearing a conversation. These factors obviously include determinants such as genetics, health status, gender-related differences, exposure to noise and possible conditioning effects of low-level noise exposure.

When applied as a tool for hearing aid fitting, categorical loudness scaling (CLS) is time consuming and not feasible in all subjects. It is therefore desirable to use objective measures for accurate prediction of loudness categories among hearing-impaired individuals. The present study aimed at exploring whether loudness perception at the ART is constant with varying hearing threshold. Seventy-five subjects with various degrees of hearing impairment, measurable acoustic reflex and normal middle ear function participated. The HTLs, ARTs and the levels of six loudness categories at frequencies 0.5, 1, 2 and 4 kHz were determined for all subjects. Loudness at the ART was found to be correlated with the amount of hearing loss. On the basis of these results, it is concluded that the ART cannot be used for accurate estimation of loudness in hearing-impaired subjects.

The purpose of this study was to determine the contribution of click frequency bands (broad-band, >2000 Hz, <2000 Hz and <1000 Hz) to binaural interaction components (BICs) of the human auditory brainstem evoked potentials (ABEPs). The human BICs were studied by subtracting the potentials to binaural clicks from the algebraic sum of monaurally evoked potentials to either ear. Effective frequency bands were derived using clicks alone or clicks with ipsilateral or binaural masking noise, high- or low-pass filtered at different cut-off frequencies. Analysis included single-channel vertex-cervical spinous process VII derivation of BIC and ABEP, as well as estimating the single, centrally located dipole equivalent of the surface activity from three orthogonally positioned electrode pairs, using the three-channel Lissajous' trajectory (3-CLT) analysis. All BIC 3-CLTs included three major components (labeled BdII, BeI, and BeII) approximately corresponding in latency to IIIn, V and VI ABEP peaks. All apex latencies of BIC 3-CLT, except BeI, were longer in response to <2000 Hz and <1000 Hz (low-frequency) effective clicks. Apex amplitude of components BeI and BeII of BIC 3-CLT were smaller with low-frequency effective clicks than with broad-band or high-frequency (>2000 Hz) clicks. We suggest that binaural interaction component BeI is mainly tuned to high frequencies, showing no frequency effect on latency, and decreasing in amplitude with decreasing click high frequency content. In contrast, BdII and BeII of the human BICs are evoked more synchronously by high-frequency binaural inputs, but are also sensitive to low frequencies, increasing in latency according to the cochleotopic activation pattern. These differences between BIC components may reflect their roles in sound localization.

The Vibrant soundbridge is a semi-implantable hearing device. The implanted electromagnetic transducer is attached to the incus and it is linked by telemetry to the externally worn audio processor. In Nijmegen, this device has been applied to seven patients with moderate or severe sensorineural hearing loss (PTA between 43 and 71 dB HL) who could not tolerate ear moulds. As the amplification of the device depends on the input level (amplifier with wide dynamic range compression), loudness scaling measurements were performed. The gain as a function of input level was determined from aided and unaided loudness growth curves. The mean gain was 21 dB at an input level of 40 dB SPL. The mean gain decreased to 5 dB at an input level of 90 dB SPL. Measured gain values were lower than target values prescribed by the FIG6 method, mainly however for the low-frequency range and for low-level sounds. It was concluded that this device is very promising for patients who cannot tolerate an ear mould.

Auditory brainstem responses (ABRs) were recorded in 60 male or female, anxious or anxiety-free university students, before and after separated or simultaneous intake of alprazolam and exposure to noise. A significant increase of the latencies of the ABRs was found when subjects took alprazolam. This effect is consistent with the presence of gamma-aminobutyric acid (GABA), one of the neurotransmitters at terminals of cochlear efferent fibres A significant increase of the latencies was observed after noise alone. In subjects taking alprazolam when they are exposed to noise, the effect of noise on the ABR latencies is reduced, but not abolished. The effects of alprazolam on the ABR are consistent with the presence of GABA in the medulla and pons. Significant effects of noise upon III-V and I-V intervals suggest that auditory 'fatigue' may involve a retrocochlear component. Differences due to sex appear to be abolished by anxiety.

The present paper reports on the implementation of a neonatal hearing screening programme in a private hospital in Belgium. A maternity-based neonatal hearing screening project with transient evoked otoacoustic emissions (TEOAEs) was started in 1993. The cost of the test was not covered by the public health insurance, so the parents had to pay the full cost for screening their child (approximately 30 Euro). Since 1993 the programme strategies have been changed on several occasions to improve the quality and efficacy. A retrospective analysis was performed on: (1) the test pass rate; (2) the coverage; and (3) the number of children who become 'Lost to follow-up' after failing the initial test. The data show a steady learning curve with a time course of several years. They also demonstrate that it is worthwhile and feasible to run a high-quality screening programme in a private establishment.

The incidence of and inter-relationship between audiogram fine structure and spontaneous otoacoustic emissions (SOAEs) was investigated in patients with Menière's disease. This project is a part of a comprehensive longitudinal study in which a range of tests of cochlear and vestibular function in patients who suffer from Menière's disease, is carried out and repeated over time. In this paper we present preliminary data from both ears (in most cases an affected and an unaffected ear) of 13 patients. The thresholds in these 26 ears ranged from normal to 80 dB HL. SOAEs could be measured in only four ears; these ears had near-normal thresholds. Data from seven ears had to be excluded because of the possibility of cross-over effects. In 16 out of the 19 remaining ears, audiogram fine structure was found. Our data confirm that (1) SOAEs correspond to behavioural sensitivity peaks. (2) There is no simple relationship between SOAE level and height of sensitivity peaks. (3) Sensitivity peaks may occur at frequencies without measurable SOAEs. In addition, our data show that: (1) Audiogram fine structure may occur in ears without observable SOAEs. (2) Fine structure can be present in ears without normal thresholds. (3) There is a weak tendency for fine structure to be more pronounced in ears with milder hearing loss.

Click evoked otoacoustic emissions (CEOAEs), pure-tone audiograms (PTAs), and Bekesy sweep frequency audiograms were recorded from 15 ears of 11 subjects with noise-induced hearing loss. For all ears, hearing threshold levels > or = 30 dB HL were found at the high frequencies. The aims of the study were to examine whether the decomposition of CEOAEs into narrow band components could identify hearing loss in a frequency-specific manner and to what extent audiometric thresholds could be predicted. CEOAEs were parcelled into 0.5-kHz-wide components by means of the wavelet transform. Reproducibility of CEOAE components was compared with audiometric threshold at corresponding frequencies. A general trend of low reproducibility for increasing audiometric thresholds was found. A reproducibility value of 60 per cent was found to best separate normal and elevated thresholds. The presence of a CEOAE component at a given frequency was always associated with audiometric thresholds < or = 20-25 dB HL. On the other hand, the absence of a component was equally associated either with normal or abnormal hearing levels. Large inter-subject variability was observed. A weak linear relationship was found between reproducibility and audiometric thresholds at corresponding frequencies, indicating that analysis of narrow band CEOAE components is valuable for separating normal from hearing-impaired ears but cannot replace the audiogram.