Dual-task repetition alters event-related brain potentials and task performance

Objective: We examined the modulation of event-related brain potentials (ERPs) and the accuracy of sensori-motor coordination on short-term repetition of the concurrent performance of a somatosensory discrimination (oddball) task and a visuo-motor tracking task. Methods: The subjects concurrently performed visuomotor tracking and somatosensory oddball tasks. In the dual-task condition, the subjects performed the visuomotor tracking and somatosensory oddball tasks concurrently for about an hour. In the oddball-only condition, they performed just the oddball task for the same period. Results: Tracking performance improved with task repetition. The amplitude of the P300 elicited by somatosensory stimulation in the oddball-only condition decreased significantly with task repetition, whereas in the dual-task condition, it showed a complex pattern of change. The earlier responses were decreased in amplitude in the dual-task condition compared to the oddball-only condition, and gradually decreased with task repetition in both conditions. Conclusions: Dynamic changes in ERPs and task performance with dual-task repetition support the idea that dual-task repetition produces changes in resource allocation following the automation of stimulus processing in addition to so-called habituation. Significance: This study also provides evidence for use of ERP amplitudes as physiological indices of functionally different types of resources. (C) 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.