Dementia of the frontal type: neuropsychological and [99Tc]-HM-PAO SPET features

Dementia of the frontal type (DFT) is a degenerative disorder with early behavioral and language disturbances and with relative preservation of memory and visuospatial abilities. On neuropathology, DFT lacks the pathologic hallmarks of Alzheimer's disease (AD). We assessed the neuropsychological and SPET imaging features of 11 DFT and 16 AD patients. The two groups had similar performances on verbal learning, while the former had significantly higher nonverbal learning scores. Testing of verbal and nonverbal instrumental abilities showed that this different behavior could be due to poorer verbal fluency of DFT patients, and not necessarily to poorer learning. Neuropsychological data indicated that the often reported sparing of memory in daily functions of DFT patients can also be shown with formal neuropsychological testing of nonverbal learning. SPET showed a comparatively higher perfusion deficit of frontal regions in the left hemisphere of DFT patients, suggesting that this region might be affected more often in the disease.