Spatial negative priming in early Alzheimer's disease: evidence for reduced cognitive inhibition.
Some studies of negative priming and other tasks assumed to reflect inhibitory functions suggest a decline in inhibitory processes in Alzheimer's disease. However, none of the measures used in previous studies can be interpreted as an unambiguous reflection of distractor inhibition. The present study investigates whether reductions in negative priming associated with Alzheimer's disease reflect reduced distractor inhibition, rather than perceptual review processes. Individuals with early Alzheimer's disease were predicted to show reduced negative priming on a spatial localization task designed to provide an unambiguous measure of distractor inhibition. Sixteen clinical participants showed significantly less negative priming than old and young healthy control groups, which is interpreted as evidence for reduced distractor inhibition in early dementia. A second analysis indicated that, within the clinical sample only, negative priming effect size was significantly correlated with prime trial response speed. Clinical participants showing the least negative priming were slower to respond to an initial stimulus. The results may mean that people with early Alzheimer's disease have a reduced capacity to use excitatory as well as inhibitory processes in selection.
Vaughan
Frances L
FL
School of Psychology, University of Wales Bangor, Bangor, United Kingdom. f.vaughan@bangor.ac.uk
Hughes
Elizabeth A
EA
Jones
Robert S P
RS
Woods
Robert T
RT
Tipper
Steven P
SP
D000367:Age Factors; D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000503:physiopathology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time; D012720:Severity of Illness Index; D013028:Space Perception / Q000502:physiology*