WAIS-R subtest profile and cortical perfusion in Alzheimer's disease

WAIS-R profiles were investigated in 28 Alzheimer's disease (AD) and 21 healthy elderly subjects. The Fuld subtest profile, previously reported to have potential as a diagnostic marker for AD, was observed in 35.7% of our AD patients and 4.8% of the controls. We compared AD patients with the Fuld profile (ADF+) to a group of patients without the profile (ADF-) with similar demographics and dementia severity and demographically matched normals using regional Cerebral Blood Flow. Both AD groups showed reduced blood flow in the parietotemporal cortex compared to normals, but the ADF+ patients had greater flow reductions than the ADF- group. Examination of WAIS-R performance indicated that the ADF+ group had lower scores than the ADF- patients on the Digit Symbol and Block Design subtests, and further, that these two subtests were associated with the parietotemporal perfusion deficit in our AD sample. Our findings do not support the use of the Fuld profile as a diagnostic marker for AD, but do provide physiological evidence for behavioral heterogeneity among AD patients based on WAIS-R subtest performance.