The Effects of 2 mA and 4 mA Cerebellar Transcranial Direct Current Stimulation and Balance Training to Reduce Fall Risk in People With Multiple Sclerosis

Many people with multiple sclerosis (PwMS) have decreased balance and postural control, gait deficits, and a high frequency of falls. High fall rates and mobility impairments pose a significant risk to the independence and quality of life of PwMS. Therefore, effective interventions to improve balance and postural control are urgently needed to decrease the frequency of falls in PwMS. Balance training has been demonstrated to significantly improve postural control and gait in PwMS. One possible treatment modality to amplify the effects of balance training is transcranial direct current stimulation (tDCS), a non-invasive means to increase cortical excitability and potentially prime the brain for task specific learning. The cerebellum plays a vital role in balance and posture and may be an important target structure for tDCS studies seeking to reduce fall risk. Studies have shown that anodal cerebellar tDCS is effective in improving balance control in older adults with high fall risk and patients with chronic stroke. However, the most effective tDCS intensity and the duration of the effects on balance control has not been established. Moreover, no study has combined cerebellar tDCS and balance training to reduce fall risk in PwMS. The purpose of this study is to investigate the effects of cerebellar transcranial direct current stimulation (tDCS) on fall risk in people with relapsing-remitting multiple sclerosis. We will conduct tDCS or SHAM followed by balance training on 4 consecutive days. We will evaluate fall risk with well-established functional tasks, such as the Berg Balance Scale, Timed Up and Go (TUG), the six minute walk test (6MWT), and static posturography.

Prospective participants, men and women with relapsing-remitting MS, will be recruited. To accomplish this study, 30 participants will be randomly assigned into 3 groups (2 mA tDCS, 4 mA tDCS, or SHAM). This study involves 4 daily visits at the Integrative Neurophysiology Lab at the same time of day for each subject and three follow-up visits. The duration of visit 1 will be approximately 2.5 hours and the duration of visits 2-4 will be approximately 1.5 hours. Visit 5, 6, and 7 will be approximately 24 hours, 1 week, and 3 weeks, respectively, after visit 4 and will last approximately 1.5 hours. During tDCS sessions, participants will undergo either Sham, 2 mA, and 4 mA tDCS for 20 minutes followed by balance training.