Effects of Anodal tDCS Applied Over the Cerebellum Combined with Physical Therapy on Center of Gravity Sway in a Patient with Cerebellar Ataxia: A Single-Case Study

Abstract

Damage to the cerebellum results in dysfunctional standing postural control. Patients with cerebellar ataxia have a larger sway in the center of gravity (COG) while standing. Transcranial direct current stimulation (tDCS) has been applied in the rehabilitation of patients with central nervous system disorders; however, its effect on COG sway in patients with cerebellar ataxia remains unknown. We aimed to confirm the effects of anodal cerebellar tDCS (ctDCS) combined with physical therapy on COG sway in a patient with cerebellar ataxia using a retrospective ABA single-case study design. This study involved a patient with left cerebellar hemorrhage. Walking and postural balance rehabilitation were conducted in phase A. Anodal ctDCS was combined with the walking and postural balance rehabilitation in phase B. We measured COG sway in the open- and closed-eyes standing conditions daily throughout all the phases. In the open-eyes standing condition, there was no significant change in COG sway in phase B. Conversely, in the closed-eyes standing condition, the circumferential area, total sway path length, and anteroposterior sway path length decreased in phase B. No change was observed in the mediolateral sway path length. The combination of anodal ctDCS and physical therapy may decrease COG sway in patients with cerebellar ataxia in the closed-eyes standing condition, and its effect may be greater in the anteroposterior direction.

Keywords: Center of gravity sway; Cerebellar ataxia; Cerebellum; tDCS.