Diagnosing Cochlear Dead Regions in Children

A dead region (DR) is defined as a region in the cochlea where inner hair cells and/or neurons are functioning so poorly that a tone producing peak vibration in this region is detected by off-frequency listening, i.e., via a place on the basilar membrane with a characteristic frequency different from that of the tone. The presence of a DR can have a significant effect on the perception of speech. People with and without DRs may differ in the benefit obtained from amplification and require different hearing aid settings. The Threshold Equalizing Noise (TEN) test and psychophysical tuning curves (PTCs) are two procedures used to identify a DR in adults. Because diagnosing a DR involves measuring masked thresholds, and there are reports in the literature that young children perform poorly compared with adults in background noise, it may be possible that the criteria used with adults may not be appropriate when testing children. Therefore, the aim of this study was to evaluate the consistency of the fast-PTC and TEN tests in diagnosing a DR in hearing-impaired children. In addition, the masked thresholds for normal-hearing children were measured with different TEN levels to assess whether any age-related effect in children compared with adults may occur.