The authors examined the presence of significant regional cerebral blood
flow (rCBF) differences between Alzheimer's disease (AD) patients with and
without extrapyramidal signs (EPS). Nine patients with probable AD and EPS
(resting tremor or rigidity and bradykinesia) and 9 AD patients without
EPS, comparable in age, duration of illness, and global cognitive decline,
were studied with [99mTc]HMPAO SPECT. Patients with 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 accounted for the decreased rCBF in
these areas. These findings suggest that the presence of EPS in AD may
result from dysfunction in specific brain regions.