Use of Modern Classification Systems for the Complex Diagnostics of Alzheimer’s Disease

Objective. To compare levels of Aβ40, Aβ42, total tau protein, and tau protein phosphorylated at threonine 181 in cerebrospinal fl uid (CSF) with clinical diagnoses of Alzheimer’s disease (AD). Materials and methods. The study was conducted in 64 patients with diagnoses of dementia and Mini-Mental State Examination (MMSE) scores of 24 points or lower. All patients underwent lumbar puncture. Aβ40 and Aβ42 levels, the Aβ42/40 ratio, and levels of total Tau and Tau phosphorylated at threonine 181 were determined in CSF using a multiplex assay following the manufacturer’s protocol. Concentrations were expressed in pg/ml. Results. Prior clinical diagnoses of AD had been made in only three patients (5%). The study revealed increased contents of AD-typical pathological proteins in the CSF in 48 subjects (75%). The data obtained indicate that the diagnosis of AD is made 10–14 times less frequently, according to global statistics, than might be expected. The discrepancy between the clinical diagnosis and laboratory data is confi rmed by our study. Conclusions. Differences in the treatment of dementia and the development of new drugs targeting specifi c elements in the pathogenesis of different types of dementia require accurate and complete diagnosis of dementia, especially AD as the most common form of this disease.