Patterns of cortical activity and memory performance in Alzheimer's disease.
BACKGROUND
Declarative memory changes are the hallmark of Alzheimer's disease, although their functional neuroanatomy is not restricted to a single structure. Factor analysis provides statistical methods for evaluating patterns of cerebral changes in regional glucose uptake.


METHODS
Thirty-three Alzheimer's patients and 33 age- and gender-matched control subjects were studied with magnetic resonance imaging and positron emission tomography with [(18)F] deoxyglucose. During the tracer-uptake period, subjects performed a serial verbal learning task. Cortical activity was measured in 32 regions of interest, four in each lobe on both hemispheres.


RESULTS
Factor analysis with varimax rotation identified seven factors explaining 80% of the variance ("parietal cortex," "occipital cortex," "right temporo-prefrontal areas," "frontal cortex," "motor strip," "left temporal cortex," and "posterior temporal cortex"). Relative to control subjects, Alzheimer's patients showed significantly reduced values on the factors occipital cortex, right temporo-prefrontal areas, frontal cortex, and left temporal cortex. The factor temporo-prefrontal areas showed large differences between patients with good and poor performance, but little difference when control subjects were similarly divided.


CONCLUSIONS
Findings suggest that Alzheimer's disease is characterized by altered patterns of cortical activity, rather than deficits in a single location, and emphasize the importance of right temporo-prefrontal circuitry for understanding memory deficits.
Section of Gerontopsychiatry, Department of Psychiatry, University of Heidelberg, Heidelberg, Germany.
J
J
Schröder
M S
MS
Buchsbaum
L
L
Shihabuddin
C
C
Tang
T C
TC
Wei
J
J
Spiegel-Cohen
E A
EA
Hazlett
L
L
Abel
C
C
Luu-Hsia
T M
TM
Ciaravolo
D
D
Marin
K L
KL
Davis
D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism*; D001921:Brain / Q000033:anatomy & histology; D002540:Cerebral Cortex / Q000098:blood supply* / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis*; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000098:blood supply / Q000378:metabolism; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013702:Temporal Lobe / Q000098:blood supply / Q000378:metabolism; D013997:Time Factors; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18