LETTER AND CATEGORY FLUENCY IN PATIENTS WITH FRONTAL-LOBE LESIONS

This study examines the hypothesis that patients with frontal lobe les ions are impaired on tests of letter but not category fluency. This hy pothesis was proposed by Moscovitch (1994), based on a series of cogni tive studies with young. normal participants. A group of patients with lateral prefrontal lesions and age-matched controls were tested on 2 tests of verbal fluency, the FAS task and a category fluency task that used semantic categories as cues (e.g., animals). Patients with front al lobe lesions generated fewer items than controls on both letter and category fluency. This effect did not interact with the type of fluen cy test, suggesting that the frontal lobes are more generally involved in verbal fluency. Moreover, this pattern of findings, along with pre vious results of impaired free recall and remote retrieval in this pat ient group, suggests that patients with frontal lobe lesions do not ef ficiently organize and develop retrieval strategies.