Ten patients with probable Alzheimer's disease were assessed at baseline and a mean 2 years later using a battery of neuropsychological tests, CT scans and Tc99m-HMPAO SPECT scans. The subjects had declined significantly in their functional indices. Cerebral perfusion measures declined in the parietal lobes, left hemisphere and whole brain, but the overall decline did not reach statistical significance. The decline in brain perfusion did not correlate significantly with the decline in various indices of neuropsychological function, either globally or for specific brain regions. The index of cerebral perfusion correlated significantly with global indices of neuropsychological function at baseline but not at follow-up. No single perfusion index was a significant predictor of clinical progression of dementia.