FUNCTIONAL IMAGING OF THE FRONTAL LOBES IN ORGANIC DEMENTIA - REGIONAL CEREBRAL BLOOD-FLOW FINDINGS IN NORMALS, IN PATIENTS WITH FRONTOTEMPORAL DEMENTIA AND IN PATIENTS WITH ALZHEIMERS-DISEASE, PERFORMING A WORD FLUENCY TEST

Patterns of functional cortical activation were studied by means of re gional cerebral blood flow measurements, performed during rest and dur ing a word fluency task in normal subjects (n = 22), in patients with Alzheimer's disease (n = 17), and in patients with frontotemporal deme ntia (n = 15). Although all groups showed a significant activation of the Broca's area during word production, the activation of the dorsola teral prefrontal cortex was clearly subnormal in both dementia groups. The frontal dysfunction was not explained by number of words produced , illness duration, or age. Thus, the results demonstrate that the wor d fluency task is a sensitive measure of frontal lobe function, and it s incorporation in imaging studies may facilitate the detection of sub tle functional impairment of the frontal lobes in organic dementia.