Similar patterns of cognitive deficits in the preclinical phases of vascular dementia and Alzheimer's disease
We investigated whether (1) cognitive deficits are present among persons who will be diagnosed with vascular dementia (VaD) 3 years later, and (2) the pattern of such deficits is similar to that observed in preclinical Alzheimer's disease (AD). The VaD diagnosis was a diagnosis of post-stroke dementia. Population-based samples of 15 incident VaD cases, 43 incident AD cases, and 149 normal controls were compared on tests of episodic and short-term memory, verbal fluency, and visuospatial skill. Both dementia groups showed preclinical impairment relative controls on tasks assessing episodic memory 3 years before diagnosis, and there were no differences between these groups on any cognitive measure. The existence of a preclinical phase in the present VaD cases suggests that circulatory disturbance may affect cognitive performance before the occurrence of stroke that leads to clinical VaD. These results extend previous findings of similar patterns of cognitive deficits in the early clinical phases of AD and VaD to the preclinical phases of these diseases. (JINS, 2004, 10, 382–391.)(Received January 2 2003)
(Revised August 19 2003)
(Accepted September 22 2003)
Key Words: Preclinical dementia; Cognition; Episodic memory.
c1 Reprint requests to: Erika Jonsson Laukka, Stockholm Gerontology Research Center, Box 6401, 113 82 Stockholm, Sweden. E-mail: Erika.Jonsson@neurotec.ki.se