Electroencephalic Audiometry by Cortical Conditioning

Abstract

Twenty-four normal-hearing adults were conditioned to associate a flash of light (unconditioned stimulus) with a pure tone (conditioned stimulus). The contingent response was used to estimate auditory threshold for 500, 1000, and 2000 Hz. Results showed that 23 of the 24 subjects were conditioned to form the tone-light association, the majority within 10 trials. Conditioned EEG responses varied in form, amplitude, and latency within and among individuals, and were without hemispheric predominance. The evoked EEG response habituated rapidly, whereas the conditioned EEG response was maintained throughout the procedure and transferred readily among the test frequencies. Auditory threshold estimated by this method was within 5 dB of voluntary threshold for at least one of the test frequencies for all 23 of the conditioned subjects.