Absolute sensitivity measured psychophysically and using auditory steady-state potentials.
Absolute thresholds were measured psychophysically (behaviorally) and physiologically in the same subjects. Psychophysical thresholds were obtained using a modified method of limits. Physiological thresholds were based on auditory steady-state potentials recorded from the scalp. The stimuli for both types of test were click trains, periodic tone bursts and amplitude-modulated tones. The center frequency of the bursts and amplitude-modulated tones was 480 or 2000 Hz. It was found that psychophysical thresholds improved, and physiological thresholds worsened as the stimulus became more frequency-specific. Because of this interaction, the differences between psychophysical and physiological thresholds increased monotonically as a function of frequency specificity. Physiological thresholds obtained with the low-frequency stimuli were lower than those acquired with the high-frequency stimuli, while psychophysical thresholds obtained with the two frequencies were essentially the same.
Champlin
C A
CA
Department of Speech Communication, University of Texas at Austin.
O'Neal
J
J
D000161:Acoustic Stimulation; D000328:Adult; D001309:Auditory Threshold / Q000502:physiology; D004558:Electric Stimulation; D004566:Electrodes; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D011601:Psychophysics