As human beings live longer, geriatric disease develop, one of which was stroke whose prevalence elevated by aging. Increased spasticity is a common symptom after stroke and may hinder patient from rehabilitation. The spasticity was evaluated by subjective judgement before. However, in the recent studies, the electrophysiological test, an objective evaluation, showed possibly positive correlation with the spasticity. They compared stroke patients' hemiplegic side with non-hemiplegic side by H/M ratio which showed significant difference. The stroke patients included in studies had stroke onset over 2 years. Therefore, investigators wonder if H/M ratio can evaluate spasticity in stroke patients onset within 2 years and if H/M ratio is correlated to spasticity.

Stroke is a condition that insufficient brain blood supply due to ischemia or hemorrhage causes brain cell death, which impacts normal function of motor, sensory, and speech, depending on the damaged location. Over the world wide, the incidence of stroke is 119 per 100,000 population per year with death rate up to 10-42% in one month after stroke. The survivor developed varying degrees of spasticity up to 42.6%.

In the conventional physical examination, modified Ashworth scale is used to evaluate spasticity, but its results may be influenced by temperature, joints range of motion, subjective judgement by tester or patient's nervousness. In the previous studies, spasticity between hemiplegic side and sound side showed significant difference in ratio of H/M amplitude, H/M threshold and H/M slope. Among them, H/M slope is the most sensitive tool and may be correlated to increased spasticity because H/M slope showed higher value in people with Brunnstrom stage III.

However, patients included in previous studies had disease onset over 2 years. The gold recovery stage after stroke is within 6 months. During this time, many methods can be used to reduce spasticity, such as medicine, stretching exercise, and injection. Therefore, it is very important whether H/M ratio for spasticity evaluation can be performed in patients with disease onset less than 2 years.

In our study, according to onset time, participants will be assigned to three groups: less than 6 months, 6 months to 2 years, and over 2 years. All the participants will accept electrophysiological test over four limbs to collect data of H/M ratio of slope, maximal amplitude and threshold. Hemiplegic side will be compared with sound side for significant difference. The relation between H/M ratio and modified Ashworth Scale will also be identified.

Inclusion Criteria:

• Single episode of stroke
• Single side hemiplegia after stroke

Exclusion Criteria:

• Other diagnosis of neurovascular disease or major cardiovascular disease
• Poor cognition
• Poor cooperation
• Aphasia
• People who can not tolerate the exam

Inpatient or outpatient at department of physical medicine and rehabilitation