Dynamic Stabilometry Combined With Transcranial Direct Current Stimulation for Balance and Motor Recovery After Ischemic Stroke

Background and Rationale. Stroke is a leading cause of long-term disability. Motor impairment, primarily hemiparesis, occurs in 60-80% of stroke survivors and limits functional independence and quality of life. The early recovery period (7-30 days after stroke onset) is characterized by enhanced neuroplasticity and is considered an optimal window for intensive rehabilitation.

Dynamic stabilometry with biofeedback is active postural control training: the patient receives real-time visual and auditory information on the position of the center of pressure while balancing on a moving platform. Unlike static stabilometry, the dynamic mode creates a controlled sensory load on the postural system and engages adaptive cerebellar-cortical mechanisms. Anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) increases cortical excitability and may potentiate motor learning. tDCS combined with active motor training has shown synergistic effects, but its combination with dynamic stabilometry has not been studied.

Interventions. Dynamic stabilometry is performed on the ReviStabix stabilometric trainer (Samara State Medical University; Russian medical device registration No. G004-00110-00/03075665 of August 29, 2025) in dynamic mode with visual and auditory biofeedback, at a fixed standard platform angle. In the control condition the platform is locked (static mode). tDCS is delivered with the Neurostim device (Neurosoft, Russia; registration certificate No. RZN 2021/13529 of February 20, 2021): anodal stimulation, 2 mA, electrode area 35 cm², 20 minutes; anode over M1, cathode over the supraorbital area. Stimulation starts simultaneously with the stabilometry session. Sham tDCS uses the same electrode montage; current is delivered for the first 30 seconds and then switched off automatically.

Study Design and Participant Groups. This is a prospective, single-center, pilot randomized controlled trial with a 2×2 factorial design (dynamic vs static stabilometry × active vs sham tDCS). A total of 120 patients aged 30-85 years with ischemic stroke and mild to moderate hemiparesis will be randomized 1:1:1:1 into four groups of 30: (A) dynamic stabilometry + active tDCS; (B) dynamic stabilometry + sham tDCS; (C) static stabilometry + active tDCS; (D) static stabilometry + sham tDCS. Randomization is in blocks of 8, stratified by age (<65 / ≥65 years) and side of the lesion (left / right hemisphere), with allocation concealment by sealed opaque envelopes or centralized web-based randomization. Participants are blinded to the type of stimulation (active / sham), and outcome assessors are blinded to group allocation.

What Participation Involves. All groups receive standard rehabilitation of equal volume (exercise therapy, physiotherapy), recorded in a session log. The study course consists of 10 sessions of 20 minutes over 12 days (5 sessions per week on weekdays). Assessments are performed at baseline (Day 0), Day 6 and Day 12: Berg Balance Scale (primary outcome), Functional Independence Measure, Morse Fall Scale, Hauser Ambulation Index, modified Rankin Scale, Rivermead Mobility Index, National Institutes of Health Stroke Scale, Medical Research Council muscle strength scale and Modified Ashworth Scale. Adverse events are recorded throughout the course.

Statistical Analysis. The primary analysis is ANCOVA of Day 12 BBS adjusted for baseline BBS, in the intention-to-treat population. Mixed ANOVA is used for changes across Day 0, 6 and 12, and 2×2 factorial ANOVA to test the interaction (dynamic stabilometry × tDCS). Effect sizes are expressed as Cohen's d; α = 0.05, power 80%. Sample size assumes an expected BBS difference of 6 points (SD 10, d = 0.6).