Enhanced preattentive central nervous system reactivity in irritable bowel syndrome.

OBJECTIVE

Irritable bowel syndrome (IBS) is a common functional disorder characterized by enhanced perceptual sensitivity and hypervigilance toward afferent signals from the viscera. We hypothesize that the increased responsiveness of IBS patients is a generalized phenomenon applying to stimuli other than visceral and attempt to demonstrate increased responsiveness to sounds as measured by the P1 scalp potential.

METHODS

Event-related potentials were recorded from IBS patients and control subjects in an auditory task requiring detection of rare pitch targets in a designated ear. Visual words served as targets in an additional block.

RESULTS

Compared to control subjects, IBS patients displayed a robust increase in the amplitude of the P1 scalp potential elicited by both attended and unattended sounds.

CONCLUSIONS

Enhanced P1 indicates preattentive central nervous system dishabituation in response to repeated sounds. A generalized preattentive increase in central nervous system reactivity may be a feature that IBS shares with several anxiety disorders that frequently co-occur in these patients.