Auditory steady-state responses for estimating moderate hearing loss.

The auditory steady-state response (ASSR) has gained popularity as an alternative technique for objective audiometry but its use in less severe degrees of hearing loss has been questioned. The aim of this study was to investigate the usefulness of the ASSR in estimating moderate degrees of hearing loss. Seven subjects (12 ears) with moderate sensorineural hearing loss between 15 and 18 years of age were enrolled in the study. Forty-eight behavioural and ASSR thresholds were obtained across the frequencies of 0.5, 1, 2, and 4 kHz. ASSR thresholds were determined using a dichotic multiple frequency recording technique. Mean threshold differences varied between 2 and 8 dB (+/-7-10 dB SD) across frequencies. The highest difference and variability was recorded at 0.5 kHz. The frequencies 1-4 kHz also revealed significantly better correlations (0.74-0.88) compared to 0.5 kHz (0.31). Comparing correlation coefficients for behavioural thresholds less than 60 and 60 dB and higher revealed a significant difference. Eighty-six percent of ASSR thresholds corresponded within 5 dB of moderate to severe behavioural thresholds compared to only 29% for mild to moderate thresholds in this study. The results confirm that the ASSR can reliably estimate behavioural thresholds of 60 dB and higher, but due to increased variability, caution is recommended when estimating behavioural thresholds of less than 60 dB, especially at 0.5 kHz.