Strategy application disorder: the role of the frontal lobes in human multitasking

Strategy application disorder is a term used to describe a pattern of deficits, usually associated with frontal lobe dysfunction, where people show disorganisation, absentmindedness and problems with planning and decision making in everyday life despite normal performance on traditional neuropsychological tests. It is argued that the prototypical situation which presents problems for these cases are those which require multitasking, and although good cases are rare in the literature, those that do exist show a characteristic neuropsychological pattern. Moreover, this pattern is confirmed in recent group studies of multitasking and of the relationship between multitasking tests (such as the Six Element Test), failures in everyday life and other neuropsychological measures. At present the evidence suggests that the potential frontal brain regions most implicated in multitasking are the anterior cingulate; B.A. 10 and immediately adjacent areas; and the right dorsolateral prefrontal cortex, with each making a unique contribution to different aspects of performance. Furthermore, recent studies show striking dissociations between performances on multitasking tests and two of the most commonly administered measures of executive function: the verbal fluency test and the Wisconsin Card Sorting Test, which sets a minimum level for a fractionation of the executive syndrome in humans.