FREQUENCY-SPECIFIC AUDIOMETRY USING STEADY-STATE RESPONSES

Objective: To evaluate the audiometric usefulness of steady-state resp onses to multiple simultaneous tones, amplitude-modulated at 75 to 110 Hz. Design: Steady-state responses to multiple tones amplitude-modula ted at different rates between 75 and 110 Hz and presented simultaneou sly were recorded at different intensities in normal adults, well babi es, normal adults with;simulated hearing loss, and adolescents with kn own hearing losses. Response thresholds were compared with behavioral thresholds. Results: In normal adults the thresholds for steady-state responses to tones of 0.5, 1, 2, and 4 kHz were 14 +/- 11, 12 +/- 11, 11 +/- 8, and 13 +/- 11 dB, respectively, above behavioral thresholds for air-conducted stimuli, and 11 +/- 5, 14 +/- 8, 9 +/- 8, and 10 +/- 10 dB above behavioral thresholds for bone-conducted stimuli. In well babies tested in a quiet environment, the thresholds were 45 +/- 13, 29 +/- 10, 26 +/- 8, and 29 +/- 10 dB SPL. In adolescents with known h earing losses, the steady-state responses thresholds predict behaviora l thresholds with correlation coefficients (r) of 0.72, 0.70, 0.16, an d 0.91 at 0.5, 1, 2, and 4 kHz, respectively. Conclusion: Steady-state responses to tones amplitude-modulated at 75 to 110 Hz can be used fo r frequency-specific objective audiometry. The multiple-stimulus techn ique allows thresholds to be estimated for eight different stimuli at the same time.