We examined patterns of cerebral glucose metabolism in 33 patients with
dementia of the Alzheimer type by applying principal component analysis to
identify subgroups. Four subgroups were identified: one with predominant
parietotemporal hypometabolism (15 patients); one with paralimbic metabolic
deficits (8 patients); one with left hemisphere neocortical abnormality (5
patients); and one with frontal and parietotemporal deficit (5 patients).
Differences among the subgroups were found in neuropsychological
impairments and prevalence of psychiatric symptoms. These metabolic
subgroups could not be explained on the basis of dementia severity, illness
duration, or age, but were most likely related to an underlying pathology
with a variable regional distribution.