Progression of mild cognitive impairment to Alzheimer's disease: improved diagnostic value of the combined use of N200 latency and beta-amyloid(1-42) levels.
OBJECTIVE
The aim of this study was to investigate the role of cerebrospinal fluid beta-amyloid(1-42) levels and auditory event-related potentials (AERPs) in the progress of mild cognitive impairment (MCI) to Alzheimer's disease (AD).


METHODS
In 53 MCI patients, lumbar puncture was performed and beta-amyloid(1-42) levels were determined. Twenty patients were reexamined after 11 months. During this period, 5 of them progressed to AD. Neuropsychological and ERP analyses were performed on all patients during both baseline and endpoint examinations.


RESULTS
Compared to stable MCI patients, those that progressed to AD had significantly lower beta-amyloid(1-42) levels (Mann-Whitney test, Z = -2.952, p = 0.003; effect size r = -0.41) and significantly prolonged N200 latencies (Mann-Whitney test, Z = -3.561, p < 0.001, effect size r = -0.49). From ERP variables, only the N200 latency significantly correlated with beta-amyloid(1-42) levels (baseline examination: r(s) = -0.421, p = 0.002; follow-up examination: r(s) = -0.574, p = 0.008).


CONCLUSIONS
The combined use of these two parameters enabled discrimination of stable MCI patients from those who developed AD, with 100% sensitivity and specificity. Therefore, this method could be of high diagnostic value for the early diagnosis of AD.
Papaliagkas
Vasileios T
VT
Department of Experimental Physiology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece. vpapal@auth.gr
Anogianakis
G
G
Tsolaki
M N
MN
Koliakos
G
G
Kimiskidis
V K
VK
D000368:Aged; D000544:Alzheimer Disease / Q000097:blood / Q000175:diagnosis* / Q000523:psychology*; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid*; D015415:Biomarkers; D003072:Cognition Disorders / Q000097:blood / Q000175:diagnosis* / Q000523:psychology*; D004192:Discrimination, Psychological / Q000502:physiology; D018450:Disease Progression; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010446:Peptide Fragments / Q000134:cerebrospinal fluid*
D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)