[Change of subjective cognitive decline in first-degree relatives of patients with Alzheimer's disease: results of a 15-year prospective study].

Abstract

Objective: To evaluate the change of cognitive functioning for 15 years in non-treated first-degree relatives of patients with Alzheimer's disease (AD) with symptoms of memory loss.

Material and methods: The observation cohort included 66 relatives of the first-degree relatives of patients with AD (Centre For Mental Health Research) with subjective cognitive decline (SCD), who agreed to a routine psychometric and in-depth neuropsychological examination and subsequent participation in the prolonged observation program but refused to use any drug therapy.

Materials and methods: An open-label 15-year observational study of the change of cognitive functioning in first-degree relatives of AD patients with symptoms of memory loss (SCD) was conducted. The baseline indicators of cognitive functioning of the study were compared with similar indicators after 5, 10, and 15 years. For psychometric assessment, routine psychometric scales and tests were used (Mini-Mental State Examination; the Montreal Cognitive Assessment Test; a Clock Drawing test, a scale of general deterioration; a test of random memorization of 10 words; the Boston naming test; subtest 6 of the Wechsler test; a test of memorizing 5 geometric shapes; the Benton test; the subtest sound and categorical associations, and the G. Münsterberg test.

Results: A prospective study of a cohort of first-degree relatives of AD patients with symptoms of cognitive dysfunction showed a high risk of subsequent cognitive deterioration up to dementia. After 5 years of observation, 16.7% of subjects developed mild cognitive impairment (mci) syndrome. By year 10 of the study, mci syndrome was diagnosed in 42.4% of subjects, and in 7.6%, AD was diagnosed; in 50.0% of subjects, the initial condition did not worsen. By year 15 of observation, 30.3% of patients were diagnosed with dementia in AD and 34.85% with mci syndrome; in 34.85% of cases, the condition remained at the SCD level.

Conclusion: The results of a 15-year cognitive study in first-degree relatives of AD patients with SCD who did not receive prophylactic therapy showed a significant decrease in cognitive functioning parameters with a quite high conversion rate to MCI and/or to dementia in ad. Subsequent analysis of a complex of demographic, clinical, neuropsychological, and other risk factors for dementia due to ad contributes to determining the hereditary risk of SCD progression and developing personalized approaches to the prevention of dementia in individuals with a genetic risk of AD.