Changes in Brain Activity Associated With Upper Limb Motor Recovery

This study is to investigate changes in brain activities in acute stroke patients , and to correlate findings with clinical outcome measures. Another aim of the study is to investigate whether transcranial direct current stimulation (tDCS) could improve motor function in subjects with poor brain activity after stroke. The brain activity will be measured by single and paired pulse TMS (transcranial magnetic stimulation). The study hypothesizes that: 1. The neural mechanisms employed in patients who have different response to TMS stimulation are different. It is hypothesized that patients with no response upon TMS stimulation might have poorer motor function outcome, compared with patients with response upon TMS stimulation. 2. The result of clinical outcome measures is related with TMS measurement. 3. tDCS intervention is beneficial to subjects with poor brain activity. Clinical outcome measures will include a battery of upper limb motor tests such as upper extremity component of the Fugl-Meyer Assessment, Modified Ashworth scale for spasticity, box and block test, and manual muscle testing. Clinical outcome and TMS measurement will be assessed at within 2 weeks, 4-6 weeks and at 6 months post-stroke.