Abstract
Background: Transcranial direct current stimulation (tDCS) is a technique that can noninvasively modulate neural states in a targeted brain region. As cerebellar activity levels are associated with upper limb motor improvement after stroke, the cerebellum is a plausible target of tDCS. However, the effect of tDCS remains unclear. Here, we designed a pilot study to assess: 1) the feasibility of a study that aims to examine the effects of cerebellar tDCS combined with an intensive rehabilitation approach based on the concept of constraint-induced movement therapy (CIMT), and 2) the preliminary outcome of the combined approach on upper limb motor function in patients with stroke in the chronic stage.Methods: This pilot study has a double-blind randomized controlled design. Twenty-four chronic stroke patients with mild to moderate levels of upper limb motor impairment will be randomly assigned to an active or sham tDCS group. The participants will receive 20 min of active or sham tDCS to the contralesional cerebellum at the commencement of 4 hours of daily intensive training, repeatedly for 5 days per week for 2 weeks. The primary outcome is upper limb motor function which will be evaluated using the Action Research Arm Test. Secondary outcomes comprise scores of the Fugl-Meyer Assessment for the upper extremity and the Motor Activity Log. Additionally, neurophysiological and neuroanatomical assessments of the cerebellum will be performed using transcranial magnetic stimulation and magnetic resonance imaging. These assessments will be conducted before, at the middle, and after the 2-week intervention, and finally 1 month after the intervention. Any adverse events that occur during the study will be recorded.Discussion: Cerebellar tDCS combined with intensive upper limb training may increase the gains of motor improvement when compared to the sham condition. The present study should provide valuable evidence regarding the feasibility of the design and the efficacy of cerebellar tDCS for upper limb motor function in patients with stroke before a future large trial is conducted.Trial registration: This study has been registered at the Japan Registry of Clinical Trials (jRCTs042200078; https://jrct.niph.go.jp/en-latest-detail/jRCTs042200078). Registered 17 December 2020
Timing-dependent effects of transcranial direct current stimulation with mirror therapy on daily function and motor control in chronic stroke: a randomized controlled pilot study