The disruptive effect of chronic pain on mismatch negativity.

OBJECTIVE

To investigate the effect of chronic pain on processes that generate the mismatch negativity (MMN).

METHODS

Twelve participants with a diagnosis of chronic intractable pain were tested before and after pain treatment. During testing, event-related potentials were recorded while participants performed tasks of varying difficulty.

RESULTS

The amplitude of the MMN was found to be greater following a nerve block procedure compared to MMN amplitude when participants were experiencing chronic pain. This effect was found to occur in the MMN for difficult-to-detect tones elicited while participants were performing a simultaneous cognitively demanding visual task. MMN amplitude was found to be greater with attention to difficult-to-detect deviants during pain but not in no pain conditions.

CONCLUSIONS

These results provide an electrophysiological correlate of previous findings that high levels of pain disrupt cognition during the performance of demanding tasks.