Assessing attention: comparison of response-inhibition and traditional continuous performance tests.

The purpose of this study was to compare a recently developed response-inhibition task (Conners, 1995) to slow- and fast-event-rate versions of the traditional A-X Continuous Performance Test (CPT). Among 146 normal adults, results revealed significant differences between tasks in omission and commission error rates, reaction time, reaction time variability, and responses to critical signals. Effects of environmental noise and participant anxiety also differed for the three tasks. Traditional CPTs produced time-related performance decrements, but the response-inhibition task produced improvement across initial blocks of trials. The response-inhibition task may measure "executive control" rather than sustained attention, and therefore may represent functions of different brain systems.