Cortical vs subcortical dementia. Neuropsychological differences.

The distinction between cortical and subcortical syndromes of dementia is controversial. Clinical reports suggest that subcortical syndromes (eg, Parkinson's disease) involve less severe intellectual and memory dysfunction and lack the aphasia, agnosia, and apraxia typical of the cortical dementias (eg, dementia of the Alzheimer type). A recent neuropsychological investigation using a standardized procedure failed to confirm the distinction. We examined patients with Alzheimer's disease, patients with Parkinson's disease, and normal controls by using a neuropsychological procedure specifically designed to quantitatively evaluate the proposed clinical differences. The results differentiated these dementia syndromes, and the pattern of performance was consistent with the cortical-subcortical hypothesis.