FRONTAL LESIONS PRODUCE A DUAL-TASK DEFICIT IN SIMPLE RAPID CHOICES

This study tested the suggestion that frontal lesions produce a dual-t ask deficit in elementary tasks. We compared the performance of 8 pati ents with unilateral frontal excisions, 8 patients with temporal excis ions and 8 controls in three rapid choice tasks involving either (1) a single choice, (2) two overlapping choices with variable inter-stimul us delays, or (3) two successive choices with variable interresponse d elays. In the single-choice task, response time (RT) was similar in fr ontal and temporal groups. However, in both dual tasks, frontals showe d larger increases in RT compared to other groups. This effect was see n on both responses and was independent of the delay. These observatio ns indicate that a frontal dual-task deficit can be found in elementar y choice tasks and that this deficit is not very sensitive to inter-ch oice separation.