Frontal lobe hypometabolism predicts cognitive decline in patients with lacunar infarcts.
BACKGROUND
A proportion of patients with subcortical lacunes will suffer progressive cognitive dysfunction, but the basis for this decline is controversial and little is known about predicting cognitive decline in these patients. Studies of Alzheimer disease have shown that imaging measures of temporal and parietal metabolism and blood flow predict disease course.


OBJECTIVE
To determine whether regional cerebral glucose metabolism predicts cognitive decline by testing 2 opposing hypotheses: (1) temporoparietal activity predicts decline (based on the idea that concomitant Alzheimer disease causes decline) vs (2) frontal hypometabolism predicts decline (based on evidence that subcortical frontal circuits are especially vulnerable to small vessel ischemia).


METHODS
Prospective cohort study.


METHODS
University outpatient dementia center.


METHODS
A convenience sample of 26 patients with radiologically defined lacunes and baseline cognitive function ranging from normal to moderately demented.


METHODS
Regional cerebral metabolism was quantitated in the form of atrophy-corrected positron emission tomographic activity ratios in cortical regions that were defined a priori. Patients were followed up at a mean of 1.8 years, and the dependent variable was rate of change in the Mini-Mental State Examination score.


RESULTS
Bilateral and right hemisphere dorsolateral frontal metabolism significantly predicted cognitive decline, with right dorsolateral frontal metabolism explaining 19% of the variance. No other positron emission tomographic region was a significant predictor, nor were demographic variables or baseline Mini-Mental State Examination scores significant predictors.


CONCLUSIONS
Cognitive decline in patients with lacunes may result in part from progressive vascular compromise in subcortical frontal circuits.
Department of Neurology, University of California, Davis, CA, USA. BRReed@ucdavis.edu
B R
BR
Reed
J L
JL
Eberling
D
D
Mungas
M
M
Weiner
W J
WJ
Jagust
D000368:Aged; D000369:Aged, 80 and over; D020520:Brain Infarction / Q000175:diagnosis / Q000378:metabolism*; D003072:Cognition Disorders / Q000175:diagnosis / Q000378:metabolism*; D004734:Energy Metabolism; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism*; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales