Cortical abnormalities associated with subcortical lesions in vascular dementia. Clinical and position emission tomographic findings
D. L. Sultzer, M. E. Mahler, J. L. Cummings, W. G. Van Gorp, C. H. Hinkin and C. Brown
Department of Psychiatry and Biobehavioral Sciences, University of California-Los Angeles School of Medicine, USA.
OBJECTIVE: To examine the effects of subcortical lesions on cortical
metabolic rate and clinical symptoms in patients with vascular dementia.
METHOD: Eleven elderly patients with vascular dementia who demonstrated no
lesion involving the cerebral cortex on magnetic resonance imaging
underwent 18F-fluorodeoxyglucose positron emission tomography to assess
global cortical metabolism and metabolic activity in each cortical lobe.
Subcortical lesions on magnetic resonance imaging (periventricular
hyperintensities, deep white matter hyperintensities, and subcortical
lacunar infarcts) were measured using a graded scale of severity. Cognitive
and noncognitive symptoms were assessed with the Neurobehavioral Rating
Scale. RESULTS: Reduced cortical metabolism was generally associated with
the severity of subcortical pathologic changes, but there was substantial
heterogeneity in the relationship between subcortical lesions and cortical
metabolic activity. Mean global cortical metabolism was lower in patients
with periventricular hyperintensities in anterior subcortical regions than
in those without such lesions. The metabolic rate in the frontal cortex was
lower in patients with a lacunar infarct of the basal ganglia or thalamus
than in those without. Neurobehavioral Rating Scale total score, the Verbal
Output Disturbance factor score, and the Anxiety/Depression factor score
were correlated with the severity of white matter lesions. CONCLUSIONS:
Cortical metabolic dysfunction is related to ischemic subcortical lesions
in patients with vascular dementia. Metabolism in the frontal cortex may be
particularly dependent on pathologic alterations of subcortical nuclei.
Anxiety, depression, and the overall severity of neuropsychiatric symptoms
in vascular dementia are associated with the extent of white matter
ischemia.