[Identifying cochlear dead regions in hearing impaired children with the threshold equalizing noise test]

ABSTRACT

Regions in the cochlea with no [or very few] functioning inner hair cells and/or neurons are called dead regions. The aim of this study was to identify the cochlear dead regions in moderate to profound sensory neural hearing impaired children through the Threshold equalizing noise [TEN[HL]] test. In this cross-sectional study, the TEN[HL] was performed for the all frequencies available on test CD, on 30 children with ages ranging from five to forteen years [mean age, 8.5 +/- 2.8 years old]. In this study, 58.3% of ears were found to have a dead region for at least one frequency. Classifying by test frequencies, 20% were found to have a dead region, 24% to be inconclusive and 56% to have no dead regions. The difference between mean SNR[T] in ears with and without dead regions was statistically significant. The difference between mean absolute thresholds in two groups was statistically significant at 1000 Hz and below [p <0.05]. The results indicated a relatively high prevalence of dead regions in children with sensory neural hearing impairment, especially for frequencies at which the hearing loss exceeds 70 dB HL