Local cerebral metabolic rates of glucose in movement and language disorders from positron tomography

Positron-computed tomography with [18F]fluorodeoxyglucose to measure glucose metabolism has shown changes in the brain distant to a focal area of infarction, demonstrating that what appears as a focal abnormality represents a more widespread functional process. Several approaches are presented to better understand quantitative metabolic data and focus on caudate and basal ganglia function. Area-to-area correlations in Parkinson's and Huntington's diseases showed decreases in the number of cortical relationships compared with control subjects, suggesting that the basal ganglia are involved with the ability of cortical regions to function together. In aphasia, caudate metabolism correlated with several language measures that suggested a role in some undefined basic process, seemingly related to Broca's area function. The studies presented suggest that the caudate may involve integrating the processing of language and cognition with the execution of the resulting response. Motor and cognitive function seem related to similar and overlapping brain systems. The disruption of such systems may result in loss of both cognitive and motor aspects of a function.