Response speed, contingent negative variation and P300 in Alzheimer's disease and MCI.
BACKGROUND
Decreased speed of information processing is a hallmark of Alzheimer's disease (AD) and mild cognitive impairment (MCI). Recent studies suggest that response speed (RS) measures are very sensitive indicators of changes in longitudinal follow-up studies. Insight into the psycho-physiological underpinnings of slowed RS can be provided by measuring the associated event-related potentials (ERP).


OBJECTIVE
The current study aims to investigate the relation between RS and its psycho-physiological correlates in AD and MCI.


METHODS
Fifteen psychoactive drug-naïve AD patients, 20 MCI patients and twenty age-matched, healthy control subjects participated. Response speed was measured during a simple (SRT) and choice reaction time task (CRT). An oddball and contingent negative variation (CNV) paradigm were used to elicit ERP. To evaluate test-retest reliability (TRR), subjects underwent a similar assessment one week after the first.


RESULTS
The SRT and CRT distinguished the patient groups significantly. The P300 amplitude and latency also distinguished the groups and showed a significant correlation with response speed. The CNV amplitude did not reveal a significant difference between groups and also showed a low TRR. The TRR of the SRT, CRT and P300 amplitude and latency in general was moderate to high. The current study suggests that response speed measures on a behavioural and psycho-physiological level deserve attention as a possible marker in the diagnosis and follow-up of AD.
van Deursen
J A
JA
Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
Vuurman
E F P M
EF
Smits
L L
LL
Verhey
F R J
FR
Riedel
W J
WJ
D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000503:physiopathology*; D004569:Electroencephalography; D018913:Event-Related Potentials, P300; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*