Transcranial direct current stimulation (tDCS) has been shown not only to improve motor function but also increase cortical excitability and neural plasticity. Several studies demonstrated that the combination of tDCS and different treatments are more effective than a single tDCS alone. However, the effects of combination tDCS and neuromuscular electrical stimulation (NMES) on upper extremity motor recovery in patients with stroke have not yet been investigated. Taking into consideration the safety and feasibility of new medical technology, recruitment of healthy subjects as a pilot study. And then recruit the stroke patients to investigate the effects for the combination of tDCS and NMES on upper extremity motor recovery in stroke.

The Transcranial direct current stimulation (tDCS) and neuromuscular electrical stimulation (NMES) is non-invasive electrical stimulation, and some studies have proved efficacy of the tDCS and NMES on healthy subjects and stroke patients. However, the effects of combination tDCS and NMES on upper extremity motor recovery and neural plasticity in healthy subjects and patients with stroke have not yet been investigated. Moreover in order to discover the tDCS combine NMES of the safety and feasibility and influences on neural plasticity and motor function, the cortical excitability and functional recovery measurements (clinical scales) are taken in the healthy subjects and stroke.

The right-handed subjects will be received the combination of tDCS and NMES for 30 minutes. The changes in the hand function and cortical excitability were probed by recording movement performance scales in upper extremity and mapping of brain cortex before and after the intervention.

The patients will be assigned into one of three groups (A, B,C) by block randomization. All participants will receive regular traditional rehabilitation. In addition, three groups will receive an additional 3 weeks, 5 times per week, 30 minutes once daily, total 15 session. Group A: both tDCS and NMES conduct simultaneously for 30 minutes. Group B: combination of tDCS and sham NMES Group C: combination of sham tDCS and sham NMES.

Inclusion Criteria(healthy subjects):

1. Age: 20~65 years old
2. Who are willing to participate in the experiment
3. Signed the consent
4. Right handed

Exclusion Criteria(healthy subjects):

1. Musculoskeletal pathology or neurological disorders affecting movements in the upper limbs
2. Epilepsy or family history
3. Cardiac pacemaker
4. Metallic implant in the head
5. Pregnancy
6. Sensory complete injury in upper limb
7. Had brain surgery
8. Expected to conduct brain surgery and major surgery during the experiment
9. The patients is suitable for the experiment by investigator assessedInclusion

Inclusion Criteria(stroke):

1. Signed the informed consent
2. First-ever ischemic stroke
3. Stroke at least 6 months
4. Unilateral hemiplegia
5. No severe cognitive impairment (National Institutes of Health Stroke Scale-Level of Consciousness: 0, Level of Consciousness Questions: 0, Level of Consciousness Commands: 0)
6. Sit on a chair for more than 30 minutes independently
7. Brunnstrom recovery stage≧3 in the paretic hand
8. Muscle tone at the wrist flexor with a modified Ashworth scale≦2

Exclusion Criteria(stoke):

1. Speech disorder or global aphasia
2. Musculoskeletal pathology or neurological disorders affecting movements in the paretic upper limbs
3. Epilepsy or family history
4. Cardiac pacemaker
5. Metallic implant in the head
6. Pregnancy
7. Diabetic, peripheral vascular disease or neuropathy that attributable to sensory complete injury
8. Have intracranial space occupied lesion, ex: brain tumors, arteriovenous malformations
9. Had brain surgery
10. Meningitis and encephalitis
11. Expected to conduct brain surgery and major surgery during the experiment
12. The patients is suitable for the experiment by investigator assessed