Agreement between psychophysical tuning curves and the threshold equalizing noise test in dead region identification.

OBJECTIVE

Identification of dead regions is currently based on the results of psychophysical tuning curves (PTC) and the threshold equalizing noise (TEN) test. Summers et al (2003) found poor agreement (56%) between PTC- and TEN test results. Kluk and Moore (2005) argued that these results are explained by beat- and/or combination tone detection. The purpose of this study was to examine the diagnostic dead region relationship between PTCs, modified for beats and/or combination tone detection, and the TEN test with levels calibrated in hearing levels (HL), i.e., TEN[HL].

DESIGN

Twenty-four hearing-impaired ears were evaluated using PTCs and the TEN[HL] test.

RESULTS

The results show an agreement of about 75%, depending on the criteria applied, between PTC and the TEN[HL] test. Results also show that PTC probe levels affected diagnostic results in PTCs.

CONCLUSIONS

Recommended criteria based on the highest agreement score included a PTC shift of 20% and an 8-dB probe elevation above TEN masking levels for the TEN[HL] test. Low agreement scores and level dependent effects in PTCs and the TEN[HL] test suggest that identification of dead regions using a single test is not reliable.