Bone-Conducted Hearing Assessment with 80-Hz Multiple Auditory Steady-State Responses to Brief Tones in Adults with Normal Hearing

Objective: To investigate interactions (if any) in the bone-conduction auditory steady-state response (BC ASSR) between multiple brief tones presented simultaneously. Methods: 500-, 1,000-, 2,000-, and 4,000-Hz brief tones, repeated at a rate of 77–101 Hz, were presented using a B-71 vibrator. BC ASSR thresholds and amplitudes at 50 dB nHL were measured in two conditions where the stimulus was either presented alone or together with other stimuli. Results: Significantly larger amplitudes in the single-stimulus condition were found at 50 dB nHL. However, there was no significant threshold difference between single- and multiple-stimulus conditions. The BC ASSR thresholds (means ± SD) at 500, 1,000, 2,000, and 4,000 Hz were 96.7 ± 9.7, 75.3 ± 11.5, 65.6 ± 7.4, and 57.8 ± 7.2 dB re 1 µN ppe, respectively. Conclusion: Interactions occurred in the multiple-stimulus condition at high presentation levels, but not at threshold levels. The results of the present study imply that BC ASSR thresholds to multiple brief-tone stimuli can be assessed at the same time, at least in normal-hearing adults.