Examination of the relevance of cochlear dead regions to hearing aid fittings

Abstract

Vickers et al. [J. Acoust. Soc. Am. 110, 1164–1175 (2001)] suggested that identification of Cochlear Dead Regions (CoDR) may provide information relative to hearing aid fittings. The relationship between CoDR and hearing aid fittings was explored in the current study two ways: (1) by reviewing the hearing loss characteristics of Vickers et al. (2001) subjects with CoDR using the Articulation Index, and (2) examining the frequency of CoDR in a clinical population. Using amplified, low-pass filtered nonsense syllables Vickers et al. (2001) found a relationship between the edge of the identified high-frequency CoDR and the filter setting that provided optimal syllable recognition. Because of the severity of the high-frequency hearing loss for the CoDR group the Articulation Index results from the present study suggested that these listeners may have not benefited from high-frequency amplification because of inaudibility. The frequency of CoDR was determined in a clinical population using the Threshold Equalization Noise (TEN) test described in Moore et al. [Br. J. Audiol. 34, 205–224 (2000)]. Results suggested that CoDR are not encountered as frequently as implied in the literature. These findings have important implications on how CoDR testing relates to hearing aid fittings.