AGE-RELATED COGNITIVE DECLINE - A CLINICAL ENTITY - A LONGITUDINAL-STUDY OF CEREBRAL BLOOD-FLOW AND MEMORY PERFORMANCE

Objectives-To evaluate the changes in regional cerebral blood flow (rC BF) and memory performance in patients with age related cognitive decl ine (ARCD) who did and did not become demented during a follow up peri od. Methods-Twenty four patients with ARCD were recruited from an outp atient memory clinic, of whom 18 were followed up over a mean period o f two years. Eighteen patients with mild to moderate probable Alzheime r's disease and 18 aged normal controls were followed up over a mean p eriod of three years. Memory performance and rCBF were evaluated quant itatively at inclusion and during follow up, using single photon emiss ion computed tomography with xenon-133 injection and three subtests of the Wechsler memory scale (logical memory, paired associated learning , and digit span). Results-Patients with ARCD showed decreased rCBF an d memory performance at initial evaluation compared with controls. Fiv e of them became demented during the follow up period, with further de cline in memory and rCBF. At inclusion, the only feature that distingu ished these five patients as a group from the remainder was a pronounc ed temporoparietal asymmetry. The 13 patients with ARCD who did not be came demented still exhibited impaired memory and rCBF at follow up, b ut without any further decline and no increase in flow asymmetry. Conc lusions-Apart from patients in the preclinical phase of Alzheimer's di sease, the ARCD category includes nondemented patients who have brain dysfunction that may represent a distinct clinical entity.