A Parametric Exploration of the Paired-Stimulus Suppression Paradigm

Abstract

The paired-stimulus suppression paradigm has been used to evaluate sensory gating in the auditory nervous system. Previous work in the AHEAD Lab has employed the paired-stimulus paradigm to investigate the perception of noise level or interference during speech perception tasks. In the present study, the effects of stimulus frequency and inter-stimulus interval were investigated as two previous experiments suggested that these could influence the amount of suppression observed. The aims of this study were to evaluate the effects of stimulus frequency and inter-stimulus interval on the latencies and amplitudes of the CAEP components evoked by each stimulus. Eleven normal hearing adults were tested using paired-stimulus paradigms in which both stimuli were 500 Hz or 4000 Hz tone bursts, and the interstimulus intervals were varied in 100 ms steps between 100 and 500 ms. The results indicated that stimulus frequency had an effect on the CAEP onset response latencies and amplitudes, whereas interstimulus interval did not. Conversely, interstimulus interval had an effect on the CAEP response amplitude to the second stimulus (the suppressed response) whereas the effect of stimulus frequency was not significant. The results of these findings will be discussed with respect to the physiological mechanisms proposed to explain these differences and the possible translation of a two-stimulus suppression paradigm into a clinical test of acceptable noise level for those who use hearing aids.