cqvip:Background: Subcortical ischemic vascular dementia has been ascribed to promin ent frontal lobe dysfunction secondary to ischemic lesions in frontothalamic cir cuits. Whether smallvessel disease in fact predominantly affects the frontal lob es is not well documented. defective: To investigate the effects of subcortical lesions (lacunes and white matter lesions [WML]) on cortical function, as refl ec ted in glucose metabolism and cognitive function, in elderly individuals. Design : Cross sectional analyses of case series. Setting: Multicenter, university ba sed study of subcortical vascular dementia. Patients: Persons with normal cognit ion, mild cognitive impairment, or dementia and with and without lacunes on magn etic resonance images. Main Outcome Measures: Regional cerebral glucose metaboli sm, normalized regional metabolic activity,and neuropsychological test scores. M ajor hypotheses were that volume of lacunes and WML correlate selectively with h ypometabolism of prefrontal cortex and failure of executive cognitive ability. R esults: Lacunes correlated with metabolic rates in dorsolateral frontal cortex ( DLF); WML substantially reduced metabolic rates throughout cortex, most strongly so in DLF. When regional metabolic activity was normalized to whole brain activ ity, lacunes remained correlated with DLF activity, whereas the WML effect was n o longer found, probably because of its general distribution. Regional cerebral glucose metabolism and normalized activity in DLFalso correlated with cortical a trophy. Metabolic activity in DL F correlated with executive function, memory, and global cognitive function, whi le activity in middle temporal gyrus correlated with memory and global function but not executive function. Conclusions: The metabolic effects of lacunes and WM L are most apparent in DLF, but the effects of WML are generalized and frontal h ypometabolism correlates with memory and global impairment, cognitive as well as executive function. The effects of subcortical cerebrovascular disease appear t o converge on the frontal lobes but are diffuse, complex, and of modest magnitud e.
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