Authors studied impairment of cognitive functions in 180 patients, aged 56-74 years, with chronic blood flow deficiency in the vertebrobasilar territory. Along with neurological examination, we used MRI of the brain and the cervical spine, MRI-angiography, ultrasound Doppler method, EEG, ECG, clinical and biochemical blood testing. Cognitive functions were assessed using standard neuropsychological tests (a word retrieval test, the Mini-Mental State Examination, the Frontal Assessment battery, the Schulte test, the Landolt test, Wechsler tests, the Wisconsin Card Sorting Test and others). Neuropsychological performance was assessed before and after treatment with cavinton (25 mg intravenous during 10 days and then 10 mg 3 times daily during 3 months). The treatment improved cognitive function and the effect remained for more than 3 months.