Comparison of ultra-high frequency hearing thresholds with short increment sensitivity index results : are tests of cochlear function correlated?

Abstract

The present study investigated the possible correlation between two tests assessing cochlear function, namely Ultra-high frequency audiometry (UHFA) and the short increment sensitivity index (SISI). Ninety young adults with normal hearing aged between 18 and 30 years old were recruited in the study. Ultra-high frequency audiometry at 9, 10, 11.2, 12.5, 14 and 16 kHz and the SISI test at 1 and 2 kHz were conducted for all participants. Subjects with higher SISI test scores for 1 dB increment level at 1000 and 2000 Hz showed significantly lower (worse) average UHF thresholds in both ears, except for the 2000 Hz SISI test in the left ear. For individual frequencies, subjects with higher SISI scores at 1 dB increment level at 1000 and 2000 Hz showed significantly lower (worse) UHF thresholds at 14 and 16 kHz in right ears and 9, 14 and 16 kHz in left ears. The results suggest a need for further investigation of the degree of correlation between UHF audiometry thresholds and SISI test scores, conducted with carrier tones at various frequencies with a wider range of age groups and participants with various cochlear conditions. If there is a strong correlation between UHF audiometry thresholds and SISI test scores, SISI could act as a screener of UHF for early identification of cochlear pathology and act as a “red flag” for normal hearing patients with high risk of cochlear pathology to suggest the need for preventive measures.