Combination of P300 and CSF β-amyloid(1-42) assays may provide a potential tool in the early diagnosis of Alzheimer's disease.
OBJECTIVE
The aim of this study was to investigate the diagnostic role of CSF beta amyloid(1-42) levels and auditory event-related potentials (AERPs) in the progression of mild cognitive impairment (MCI) to Alzheimer's disease (AD).


METHODS
In fifty three MCI patients a lumbar puncture was performed and beta amyloid(1-42) levels were determined. Twenty patients were re-examined after 11 months. During this period five of them progressed to AD. Neuropsychological and ERP examinations were performed in all patients at both exams.


RESULTS
Compared to MCI stable patients, AD-converters showed significantly lower beta-amyloid(1-42) values both for group 1 (Mann Whitney test, Z=-2.952, p=0.003, effect size r=-0.41) and group 2 (Z=-2.458, p=0.011; effect size r=-0.55). On the other hand, the patients of group 1 who converted to AD had prolonged latencies and lower amplitudes of the P300 wave compared to those of the MCI-stable patients, although the differences were not significant.


CONCLUSIONS
Compared to the separate use of CSF beta-amyloid(1-42) and AERPs, higher values of sensitivity and specificity were achieved by the combined use of beta-amyloid(1-42) levels and P300 latencies (80% and 98%) or amplitudes (100% and 89%) in the discrimination between AD converters and MCI stable patients. Therefore the combination of an electrophysiological and a biological marker is potentially of high diagnostic value for the early diagnosis of AD converters.
Papaliagkas
V T
VT
Department of Experimental Physiology, Faculty of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. vpapal@auth.gr
Anogianakis
G
G
Tsolaki
M N
MN
Koliakos
G
G
Kimiskidis
V K
VK
D000161:Acoustic Stimulation / Q000379:methods; D000368:Aged; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid* / Q000175:diagnosis* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid*; D001306:Auditory Pathways / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D042241:Early Diagnosis; D004569:Electroencephalography / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000134:cerebrospinal fluid*; D011237:Predictive Value of Tests; D011379:Prognosis; D012680:Sensitivity and Specificity; D013129:Spinal Puncture / Q000379:methods
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)