Anodal high-definition transcranial direct current stimulation over the primary motor cortex enhances post-concussion postural control

Research Objectives: To investigate whether HD-tDCS over primary motor cortex can improve postural control deficits following concussion.

Design: This study employed a double-blind design, integrating both within-subjects and between-subjects approaches. Participants visited the laboratory weekly, with a minimum interval of 5 days between visits.

Setting: Brain Stimulation Lab at the University.

Participants: Participants were undergraduate and graduate students from multiple universities, comprising both genders aged 18 to 35 years. We recruited 20 participants for those with a concussion history (at least one-year post-injury).

Interventions: Treatment utilized a 4 × 1 ring-type high-definition tDCS with a wireless multichannel Starstim® neurostimulator (Neuroelectrics, Spain). Current was delivered via round gel Ag/AgCl electrodes (3.14 cm2). Anodal electrode was positioned over Cz, surrounded by return electrodes (Fc1, Fc2, Cp1, and Cp2) based on 10/20 electroencephalogram templates. HD-tDCS applied for 20 minutes with 30 seconds ramp-up and ramp-down, using 2 mA current. Sham stimulation had 30 s current delivery and then stopped.

Main Outcome Measures: The postural control tests utilized the Bertec Balance Advantage-Computerized Dynamic Posturography with Immersion Virtual Reality (CDP/IVR). Each visit began with a 15-minute warm-up of jogging and stretching, followed by posture control tests. Three tests were conducted post-intervention, with the first being immediate and the subsequent two at 20-minute intervals, all within 1.5 hours. CDP included sensory organization test (SOT).

Results: A significant interaction effect between time and session for SOTC, VIS, and VEST was revealed by the repeated-measures ANOVA (p < 0.05). Bonferroni post hoc tests indicated that all three parameters significantly increased post-tDCS compared to after the sham stimulation session (p < 0.05). In contrast, for SOM and PREF, no significant interaction effects were found between time and session (p > 0.05), and no notable differences emerged between tDCS and sham sessions in the post hoc tests (p > 0.05).

Conclusions: This study demonstrated the potential efficacy of HD-tDCS over the primary motor cortex in enhancing postural control deficits post-concussion. These findings suggest that while HD-tDCS offers promising benefits for certain postural control measures, its effects may be selective, warranting further exploration into its comprehensive therapeutic potential.

Author(s) Disclosures: The authors declare no conflicts of interest.