Diagnostic value of event-related evoked potentials N200 and P300 subcomponents in early diagnosis of Alzheimer's disease and mild cognitive impairment.
Event-related potentials (ERPs) have a large application in the evaluation of cognitive processes, particularly in Alzheimer's disease (AD). The aim of the present study was to evaluate the clinical relevance of event-related evoked potentials (N2 and P3 subcomponents) in early diagnosis of AD and mild cognitive impairment (MCI). We prospectively studied 60 subjects. They all underwent the following investigations: neurologic and neuropsychological examination; functional evaluation, i.e., ERPs; cerebral imagery (morphologic and functional). Subjects were classified into 3 groups: group 1: 30 dementia of Alzheimer type (NINCDS-ADRDA, DSM-IV criteria); group 2: 20 MCI; and group 3: 10 control subjects. ERPs were significantly different between the groups (AD, MCI, control subjects), with a marked increase of P3 latencies, particularly when compared with N2 latencies (P < 0.0001). Furthermore, sensitivity was 87% to 95% for the differentiation of AD patients from MCI and control subjects, using prolonged P3 latencies (specificity, 90% to 95%), whereas using N2 prolonged latencies, sensitivity was 70% to 75% (specificity, 70% to 90%). Moreover, in the MCI group, N2 latencies strongly discriminated MCI from control subjects, with 90% sensitivity and 70% specificity and correctly categorized 80% of MCI subjects against 73% for P3. The abnormalities of N2 and P3 components may be linked, in AD and MCI, to an alteration of automatic and controlled attention processing.
Bennys
Karim
K
Department of Neurology, University Hospital of Montpellier, France. k-bennys@chu-montpellier.fr
Portet
Florence
F
Touchon
Jacques
J
Rondouin
Gérard
G
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity