Periodic Limb Movement Syndrome in Patients With Cerebral Small Vessel Disease.

Inclusion Criteria: * Diagnosis of a cerebral small vessel disease - assessed by MRI. * Ability to follow the procedures of the study, fluent Russian language - assessed by self-report. Exclusion Criteria: * History of symptomatic stroke, brain tumor or traumatic brain injury - assessed by self-report and clinical history. * History of severe psychiatric comorbidities other than anxiety and depression, substance use disorder - assessed by self-report and clinical history. * Significant visual loss (leading to difficulties with performing cognitive tasks) - assessed by self-report and clinical history. * Presence of dementia - assessed by history and clinical examination. * Movement disorders (e.g. tremor, dystonia etc.) leading to lower velocity of performing cognitive tasks against the clock - assessed by clinical examination. * Obstructive sleep apnea syndrome - according to the criteria of International classification of sleep disorders III. * Restless legs syndrome - according to the criteria of the International restless legs syndrome study group. * Current intake of neuroleptics, benzodiazepines, selective serotonin reuptake inhibitors - assessed by self-report and clinical history.