Frequency-specif ic Auditory Brainstem Responses in Adults with Sensorineural Hearing Loss

The purpose of this study was to investigate the prediction of pure tone thresholds from auditory brainstem response (ABR) thresholds to tone bursts in noise using two formulae: (1) a correction factor based on the average difference between pure tone thresholds and ABR thresholds, and (2) a regression equation describing the relationship between pure tone thresholds and ABR thresholds. Twenty subjects with mild to moderate sensorineural hearing loss were tested with tone bursts having 1 millisecond rise-plateau-fall times in highpass noise (500 Hz) and notch noise (1000, 2000, and 4000 Hz). The data revealed that the pure tone-ABR threshold difference systematically decreased as frequency increased. Mean differences were approximately 25 dB at 500 Hz and 1000 Hz, 15 dB at 2000 Hz, and 10 dB at 4000 Hz. Using these correction factors, approximately 90 per cent of pure tone thresholds were predicted within +/- 10 dB at 2000 Hz and 4000 Hz, and within +/- 20 dB at 500 Hz and 1000 Hz. Similar results were found using the regression formulae. The results suggest that ABR thresholds to tone bursts in noise may provide valuable information on the auditory sensitivity and audiometric configuration of difficult-to-test patients.