Effects of Transcranial Direct Current Stimulation (tDCS) on Balance, Functional Performance, and Neurocognitive Function in Males with Chronic Ankle Instability: Study Protocol for a Randomized Controlled Trial

Background: Approximately 40% of individuals who experience an ankle sprain subsequently develop Chronic Ankle Instability (CAI). Recent evidence highlights alterations in Central Nervous System (CNS) function and deficits in neurocognitive performance among this population. Therefore, there is a need for interventions that target neural excitability alongside traditional physical rehabilitation.Methods: This study is a randomized, sham-controlled, single-blind clinical trial. Twenty participants with CAI will be randomly assigned to two groups (n=10 per group): (1) anodal Transcranial Direct Current Stimulation (a-tDCS) combined with exercise, and (2) sham tDCS combined with exercise. The intervention consists of 12 sessions (three times per week). Assessment of self-reported outcomes, balance, functional performance, and neurocognitive function (such as reaction time) will be conducted at baseline, mid-intervention (6th session), and post-intervention (12th session).Results: As this is a study protocol, primary results are expected to demonstrate whether the combination of a-tDCS and exercise leads to superior improvements in postural balance and neurocognitive reaction time compared to exercise with sham stimulation. It is hypothesized that tDCS will enhance neural plasticity, thereby amplifying the functional gains from the exercise program and improving self-reported stability.Conclusion: This study aims to provide empirical evidence for the role of non-invasive brain stimulation in musculoskeletal rehabilitation. If effective, tDCS could be established as a valuable complementary intervention alongside exercise therapy to address both the physical and neurocognitive deficits associated with Chronic Ankle Instability, potentially reducing the recurrence of sprains.