Cognitive function in patients with atrial fibrillation (AF) is often impaired due to the complex influence of various factors (cerebral hypoperfusion, neurodegeneration, microemboli, hypertension, chronic inflammation). This leads to impairment of cognitive functions, including attention, memory, executive functions, and speed of information processing. The search for affordable and safe methods to maintain or improve cognitive function in this group of people is an urgent task of modern medicine. One of the promising approaches is percutaneous low-frequency electrical stimulation of the auricular branch of the vagus nerve (transcutaneous Vagus Nerve Stimulation - tVNS). The auricular (auricular) branch of the vagus nerve is a peripheral branch of the vagus nerve innervating the skin of the auricle in the area of the tragus and the inner part of the external auditory canal. The tVNS engages the sensory fibres of the vagus nerve and thus mimics the sensory input to the brainstem, forming the so-called auriculo-vagal afferent pathway. Since these fibres project directly to the nucleus of the solitary pathway (solitary tract), which, in turn, has direct and indirect projections to the nuclei providing noradrenergic, endorphinergic and serotoninergic fibres in various parts of the brain regulating systemic indices of cardiovascular, respiratory and immunological functions, the organism's response to stimulation of the auricular branch of the vagus nerve is systemic in nature. Stimulation of this nerve can modulate central nervous system (CNS) activity, affecting processes related to memory, attention and emotional state. Mechanisms of action of tVNS include modulation of parasympathetic activity, enhancement of neuroplasticity through increased expression of neurotrophic factors (e.g., BDNF), improvement of cerebral blood circulation, and regulation of neuroinflammation (reduction of proinflammatory cytokines).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
60
tVNS will be performed daily after workouts for 60 minutes over a period of 6 months.
Bakulev National Medical Research Center for Cardiovascular Surgery
Moscow, Russia
Neurodynamics and Cognitive Technologies Research Laboratory of the Neuroscience Research Institute
Nizhny Novgorod, Russia
Dynamics of neural activity of the brain.
Changes in the characteristics of time-frequency analysis of the neural activity of the brain associated with the performance of a cognitive task.
Time frame: This parameter will be assessed at the beginning of the study (initially) and at the end of the study (6 months) in the active and fictitious stimulation groups.
Reaction Time (RT) Changes & EEG Correlates
Changes in reaction time (RT) during the perception and classification of ambiguous visual stimuli (Necker cubes) by a patient. The test is conducted with simultaneous EEG recording during the visual task (determining the orientation of the Necker cube - right-oriented or left-oriented configuration). The presentation of ambiguous stimuli, such as the Necker cube, leads to an increase in reaction time due to the need to resolve perceptual conflict and make decisions under uncertainty. Parallel EEG recording reveals specific neural correlates of this process (N200 - conflict, P300 - decision/classification, frontal theta - cognitive control, gamma - perceptual reorganization), which are directly related to the observed changes in reaction speed. Analysis of these EEG markers together with RT provides deep insight into brain dynamics during the processing of ambiguous information.
Time frame: This parameter will be assessed at the beginning of the study (initially) and at the end of the study (6 months) in the active and fictitious stimulation groups.
Attention Level Changes & Error Rates
Changes in the level of attention during the perception and classification of ambiguous visual stimuli (Necker cubes) by a patient. The test is conducted with simultaneous EEG recording during the visual task (determining the orientation of the Necker cube - right-oriented or left-oriented configuration). The frequency of actual errors (incorrect reporting) is assessed. The presentation of ambiguous stimuli, such as the Necker cube, requires an increased level of attention (especially executive control), reflected in specific EEG patterns (theta, N2, P3). The primary sources of errors are perceptual instability (switches during response) and unresolved conflict/uncertainty. Analysis of EEG (ERN/Pe) allows studying the process of error detection and correction itself.
Time frame: This parameter will be assessed at the beginning of the study (initially) and at the end of the study (6 months) in the active and fictitious stimulation groups.
Dynamics of the cognitive test MoCA-8 (Montreal Cognitive Assessment).
Changes in the MoCA-8 score. Scores on the MoCA-8 test range from 0 to 30, where a score \<26 may indicate cognitive impairment.
Time frame: This parameter will be assessed at the beginning of the study (initially) and at the end of the study (6 months) in the active and fictitious stimulation groups.
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