NIHL is usually diagnosed by means of the pure-tone audiogram (PTA), the gold standard for identifying hearing threshold levels of individuals, enabling determination of the degree, type, and SHP099 purchase configuration of a hearing loss. Typical patterns in the hearing thresholds (i.e. a noise notch at 3, 4, and/or 6 kHz combined with relatively normal thresholds at 8 kHz) provide a strong indication for NIHL. Kähäri et al. (2001a, b) showed that the degree of hearing impairment as expressed in the PTA in musicians is smaller than could be expected on the basis of their daily exposure.
An extensive review of literature and data of the Vancouver Symphony orchestra concluded that at least some noise-induced hearing impairment among musicians Selleck GDC-0449 can be shown from the PTA (Eaton and Gillis 2002). Yet other studies report musicians’ hearing threshold levels that do not significantly differ from those of non-exposed populations (e.g. Obeling and Poulsen 1999; Johnson et al. 1985). The discrepancy between the high number of musicians that report problems with their hearing and their relatively good pure-tone thresholds could partly be explained by selection bias by withdrawal: musicians with hearing problems could have some reservation to participate in such studies. On the other hand, the assessment selleckchem of musicians’
hearing by means of the PTA could lead to very different results than that of, for instance, workers in the building industry. With their well-trained ears and developed sensitivity to sound and music in general (Seither-Preisler et al. 2007), musicians could simply be better in detecting pure tones than
other populations. The measurement of otoacoustic emissions (OAEs) has been proposed to be a more objective and more sensitive test for assessing the effects of noise exposure than the PTA. OAEs are sounds produced by the healthy ear, by the outer hair cells (OHCs) in the cochlea. The absence of Phospholipase D1 OAEs is associated with poorly functioning outer hair cells resulting in reduced selectivity and a decreased sensitivity (e.g. Avan and Bonfils 1993; Gorga et al. 2005; Martin et al. 1990). Lapsley-Miller et al. (2004) found decreased average OAE amplitudes after 6 months of noise exposure, while the average audiometric thresholds did not (yet) change. She found no significant correlations between changes in audiometric thresholds and changes in OAEs, which is suggestive for the hypothesis that OAEs indicate noise-induced changes in the inner ear, still undetected by pure-tone audiometry. When confirmed by further experimental evidence, the measurement of OAEs could be an attractive method to assess NIHL in musicians in an early stage. Diagnosis of NIHL has often been limited to the measurement of hearing thresholds, while musicians specifically report other sound related hearing problems. Tinnitus (i.e.