Background and purpose: The progression of cognitive deterioration in patients with Alzheimer's disease (AD) is considerably variable. The ability to predict the progression rate is important for clinicians to treat and manage patients with AD. We examined the possible relationship between the rate of cognitive deterioration and regional cerebral blood flow (rCBF) patterns in patients with AD.
Methods: We followed 48 patients with AD for an average of 37 months. They were subsequently divided into the rapidly progressing group (n=24) and slowly progressing group (n=24) based on an annual Mini-Mental State Examination (MMSE) score change. Initial and follow-up rCBF were assessed using single photon emission CT (SPECT) and the SPECT data were analyzed by 3D-stereotactic surface projections.
Results: At initial evaluation, the rapidly progressing group had greater rCBF deficits mainly in the parietotemporal and frontal regions, and left posterior cingulate than did the slowly progressing group. When compared with initial SPECT, follow-up SPECT showed a significant rCBF reduction in widespread regions, including parietotemporal and frontal lobes, of the rapidly progressing group, while showed in the scattered and small regions of hemispheres of the slowly progressing group.
Conclusion: Our longitudinal SPECT study suggests a significant association between rCBF deficits in the parietotemporal, posterior cingulate, and frontal regions and subsequent rapid cognitive and rCBF deterioration.