Can the Lateralized Readiness Potential Detect Suppressed Manual Responses to Pure Tones?

BACKGROUND

Willfully not responding to auditory stimuli hampers accurate behavioral measurements. An objective measure of covert manual suppression recorded during response tasks may be useful to assess the veracity of responses to stimuli.

PURPOSE: To investigate whether the lateralized readiness potential (LRP), an electrophysiological measure of corticomotor response and suppression, may be of use in determining when participants hear but do not respond to pure tones.

RESEARCH

DESIGN

Within-subject repeated measures with a Go-NoGo paradigm.

STUDY SAMPLE: Five males and five females (mean age = 38.8 years, standard deviation = 8.8) underwent electrophysiology testing. All had normal hearing, except one.

INTERVENTION: Participants were tested in a condition where they consistently responded to tonal stimuli, and in a condition where intensity cued whether they should respond or not. Scalp-recorded cortical potentials and behavioral responses were recorded, along with a question that probed the perceived effort required to suppress responses to the stimuli.

DATA COLLECTION AND ANALYSIS: Electrophysiology data were processed with independent component analysis and epoch-based artifact rejection. Averaged group and individual LRPs were calculated.

RESULTS

Group averaged waveforms show that suppressed responses, cued by NoGo stimuli, diverge positively at approximately 300 msec poststimulus, when compared with performed (Go) responses. LRPs were comparable when Go responses were recorded in a separate condition in which participants responded to all stimuli, and when Go and NoGo trials were included in the same condition. The LRP was not observed in one participant.

CONCLUSIONS

Subsequent to further investigation, the LRP may prove suitable in assessing the suppression of responses to audiometric stimuli, and, thereby, useful in cases where functional hearing loss is suspected.