CEREBRAL METABOLIC CHANGES IN ALZHEIMERS-DISEASE - NEUROBEHAVIORAL PATTERNS

Regional cerebral glucose metabolism was surveyed in 37 Alzheimer's di sease (AD) patients and 21 normal controls using positron emission tom ography. Where possible, brain regions were specified according to the ir neurobehavioral function rather than as anatomically demarcated str uctures. Absolute metabolic values revealed significant differences (p < 0.05) between AD patients and controls for whole brain and the more superior supratentorial brain slices. Normalized values (region/brain stem) showed the most striking declines (p < 0.001) in the associatio n cortex (heteromodal region -21%; unimodal region -19%) and the prima ry sensory-motor cortex (-13%), with motor, auditory, and visual areas more affected than somatosensory areas. Limbic and paralimbic systems were equally affected (-14%; -11%; p < 0.001). Thalamus, striatum, ce rebellum and brain stem were minimally or not affected. Neurobehaviora lly defined hypometabolic regions largely parallel affected areas note d in anatomic and previous metabolic studies, with the possible except ion of metabolic deficits in the primary sensory-motor complex. Concei vably, brain areas unaffected morphologically by the pathophysiologica l processes of AD may become dysfunctional due to a disruption of conn ectivity between regions.