Pre-dementia cognitive impairment

Cognitive disorders are one of the most significant problems of older. Special attention should be paid to the diagnosis of early pre-dementia stages of cognitive impairment (CI): subjective, subtle and mild.The aim of this study was to determine the criteria of pre-mild: subjective and subtle cognitive decline (SCD).Material and methods. The study included 602 patients with pre-mild cognitive impairment with a mean age of 63.24±11.24 years and 515 patients with mild cognitive impairment aged 71.2±8.0 years. The indicators of patients were compared with those of 104 healthy people (average age 64.23±8.14 years) who did not complain of memory impairment and had no deviations during clinical and neuropsychological examination.Results and discussion. Groups of patients with subjective and subtle cognitive decline were distinguished, which differed in most characteristics. At the same time, in both groups of patients, deviations in the results of neuropsychological tests did not exceed one standard deviation from the average results for healthy people, which, in fact, allowed them to be attributed to «pre-mild» cognitive decline. The data obtained confirmed the heterogeneity of the «pre-mild» cognitive decline. The study also shows the allocation limitation of pre-mild cognitive impairment only on the basis of a formal approach based on the quantitative characteristics of neuropsychological research with a difference from control groups necessarily exceeding one standard deviation.Conclusion. The analysis showed the heterogeneity of pre-dementia and pre-mild cognitive impairments that are divided according to the degree of changes in objectively assessed cognitive functions with the similarity of subjective complaints. It is proposed to distinguish subjective cognitive decline with completely normal neuropsychological characteristics and subtle cognitive decline in the event of changes in individual indicators evaluating mainly the control functions and memory.