A SPECT STUDY OF PARKINSONISM IN ALZHEIMERS-DISEASE

The authors examined the presence of significant regional cerebral blo odflow (rCBF) differences between Alzheimer's disease (AD) patients wi th and without extrapyramidal signs (EPS). Nine patients with probable AD and EPS (resting tremor or rigidity and bradykinesia) and 9 AD pat ients without EPS, comparable in age, duration of illness, and global cognitive decline, were studied with [Tc-99m]HMPAO SPECT. Patients wit h AD and EPS showed significantly lower rCBF in the superior frontal, superior temporal, and parietal regions of the left hemisphere than AD patients without EPS. Rigidity and bradykinesia independently account ed for the decreased rCBF in these areas. These findings suggest that the presence of EPS in AD may result from dysfunction in specific brai n regions.