MEASURES OF PREFRONTAL DYSFUNCTION AFTER CLOSED-HEAD INJURY

Tasks sensitive to frontal lobe dysfunction (delayed response, delayed alternation, object alternation, and Wisconsin Card Sort) were admini stered to 20 patients with post-acute closed-head injury (CHI). Time s ince injury varied (6 to 280 months; mean, 48 months), as did length o f coma (2 hr to 120 days; mean, 38 days). Compared to normal controls, CHI patients showed no deficits on delayed response tasks, but were i mpaired on delayed alternation, object alternation, and the Wisconsin Card Sort Test. Analyses of the performance profiles of the CHI patien ts suggested that they may have difficulty in establishing set (a cons equence of damage to the orbitofrontal system). (C) 1996 Academic Pres s, Inc.