Temporal lobe perfusion on single photon emission computed tomography predicts the rate of cognitive decline in Alzheimer's disease
N. Wolfe, B. R. Reed, J. L. Eberling and W. J. Jagust
Department of Neurology, University of California, Davis-Northern California Alzheimer's Disease Center, Berkeley.
OBJECTIVE: To examine the ability of relative regional cerebral blood flow
as measured by single photon emission computed tomography to predict
longitudinal course of cognitive decline in Alzheimer's disease. DESIGN:
Single photon emission computed tomography using the blood flow tracer
123I-N-isopropyl-p-iodoamphetamine was performed at initial evaluation and
was used to predict the rate of cognitive decline over a follow-up period
from 1 to 4 years. SETTING: Outpatient university dementia clinic and
center for functional imaging. PARTICIPANTS: Twenty-nine patients met
National Institute of Neurological and Communicative Disorders and
Stroke-Alzheimer's Disease and Related Disorders Association criteria for
probably or possible AD. RESULTS: Temporal lobe regional cerebral blood
flow ratio at initial evaluation correlated with rate of decline in
Mini-Mental State Examination over the longitudinal follow-up. Temporal
regional cerebral blood flow ratio also predicted rate of decline of
specific memory measures on the California Verbal Learning Test. Neither
parietal nor frontal ratios predicted rate of cognitive decline.
Dorsolateral frontal hypoperfusion was associated with the emergence of
perseverative behaviors over time. Age, prior dementia duration, estimated
prior rate of decline, and initial severity did not predict rate of
cognitive decline. CONCLUSION: Results suggest that regional perfusion on
single photon emission computed tomography may predict cognitive decline in
Alzheimer's disease better than these demographic and course variables.