Reaction times and performance variability in normal aging, mild cognitive impairment, and Alzheimer's disease.
This study evaluated whether reaction times (RT) and performance variability are potential markers for the early detection of Alzheimer's disease (AD). Cognitively healthy elderly (n = 218), persons with amnestic MCI (a-MCI) (n = 29) and patients with AD (n = 50) were examined with RT tasks with increasing complexity, subdividing RT into a decision and a movement component. Persons with cognitive deterioration demonstrated more intra-individual variability and more slowing than cognitively healthy elderly. The slowing in AD affects both the cognitive and the motor component, while performance variability mainly affects the cognitive component of the RT. Although in a-MCI not all differences reached statistical significance, primarily the cognitive component of the RT is affected in a-MCI. Intra-individual variability and RT of the complex tasks are the best predictors for a-MCI and AD status, respectively. We conclude that performance variability can be regarded as a useful preclinical marker for AD.
Gerontology Department, Vrije Universiteit Brussel, Brussels, Belgium.
Ellen
E
Gorus
Rudi
R
De Raedt
Margareta
M
Lambert
Jean-Claude
JC
Lemper
Tony
T
Mets
D000203:Activities of Daily Living / Q000145:classification / Q000523:psychology; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D000647:Amnesia / Q000175:diagnosis / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D003657:Decision Making; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D008609:Mental Status Schedule / Q000706:statistics & numerical data; D011594:Psychometrics; D011597:Psychomotor Performance; D011930:Reaction Time; D012016:Reference Values