Abstract

Eight patients with a clinical diagnosis of probable Alzheimer's disease, eight patients with the clinical diagnosis of frontal lobe dementia, and eight controls were examined with single photon emission tomography (SPECT) using 99Tc-HMPAO. Patients with Alzheimer's disease and those with frontal lobe dementia met DSM-III-R criteria for mild dementia and were in the early stages of the illness. Compared with patients with Alzheimer's disease, the group with frontal lobe dementia had significantly lower blood flow in the frontal lobes (dorsolateral and orbital), the anterior temporal cortex, and the basal ganglia. Within the frontal lobe dementia group, blood flow was significantly lower in the orbital than in the dorsal frontal cortex, and in the anterior temporal than in the dorsal temporal cortex. The present study shows the specificity of changes in regional cerebral blood flow in the diagnosis of different types of dementia, and supports the importance of orbitofrontal, anterior temporal, and basal ganglia dysfunction in the production of the psychiatric syndrome of frontal lobe dementia.