Mental programming after frontal lobe lesions: results on digit symbol performance with self-selected goals

The aim of this study was to demonstrate that the inability to set adequate sub-goals in a cognitive task is a sensitive indicator of programming deficit after frontal lobe lesion. Sixty-one patients with focal cerebral lesions and 25 control subjects were studied with a modified Digit Symbol task, in which the score depended on the adequacy of the sub-goals set by the subject. This score was compared to that on the standard condition, in which the subject was requested to work as quickly as possible without self-selected goals. The results confirmed the prediction that patients with anterior lesions set less adequate sub-goals than patients with posterior lesions and, unlike the latter patients, have a more pronounced deficit on the performance with self-selected goals than on the standard condition. In particular patients with left frontal lobe lesions underestimated their capabilities in relation to task requirements.