Transcranial Direct Current Stimulation Combined Sensory Modulation Intervention in Chronic Stroke Patients

Background and purpose: About 30% of people with stroke suffered from severe long-term upper extremity （UE） motor impairment. Severe UE impairment, especially dysfunction of hand, can greatly impact stroke patients' daily living independence and quality of life. However, treatment effect of current interventions is still limited. Nick Ward and Leonardo Cohen suggested 5 intervention strategies for stroke motor recovery: （1） reduction of somatosensory input from the intact; （2） increase in somatosensory input from the paretic; （3） anesthesia of a body part proximal to the paretic hand; （4） activity within the affected motor cortex may be up-regulated; （5） activity within the intact motor cortex may be down-regulated. Recent studies have shown each strategy to be effective in stroke patients with mild or moderate UE impairment. However, evidence for people with severe UE impairment after stroke remains unclear. Since research has found a greater effect for combined strategies than a single strategy, this proposal develops a combined intervention with the above 5 strategies, named "transcranial direct current stimulation （tDCS） combined sensory modulation intervention". This intervention is expected to be most effective for people with severe UE impairment after stroke. In addition, neuroimaging can provide in vivo information about the brain plasticity which underpinning the motor recovery after stroke. However, image indexes that can be used in stroke patients with severe UE impairment remained examined. Therefore, this proposal has 3 aims: （1） to examine the treatment effect of the "tDCS combined sensory modulation intervention" in stroke patients with severe UE impairment; （2） to examine the underline mechanism of the efficacy of "tDCS combined sensory modulation intervention" using neuroimaging technology. Methods: This study is a double-blinded randomized controlled trial which will recruit 60 people who have had stroke onset more than 6 months and have sever