Spasticity of stroke patient, a very common complication in clinical practice, affects performance of hand function and gait pattern. It also interferes with quality of life of patients severely. Currently first line clinical approach to spasticity consist of physical therapy and pharmacological management. However, there are still some refractory cases that needed local intervention such as Botox injection.

So far, we only can use subjective methods to measure muscle tension, such as modified Ashworth scale and Tone Assessment Scale. In our previous study, we found that ultrasound shear wave image could correlate with muscle stiffness caused by poststroke spasticity. With this new method, we aim to establish a more objective method in measuring abnormal poststroke muscle tension before and after treatments and further monitor therapeutic effect. We also include several assessment scales to evaluate the correlation between measured muscle spasm and activity of daily living.

We hypothesize that the rheological changes in muscles muscle spasm after Botox injection can be detected by ultrasound shear wave image. Therapeutic effect can also be seen in its effect on daily functions.

In this project, we will use shear wave imaging of ultrasound to investigate the elasticity (and hardness) of the biceps brachii and brachialis muscle in stroke patients with unilateral hemiplegia before and after Botox injection. The findings of this project will provide the objective evaluation of muscle spasticity and its correlation with functional status, which will provide new points of view toward treatment of spasticity.

Inclusion Criteria:

[Intervention group]

• Stroke patients with unilateral involvement
• Patient's spasticity over affected upper extremities scored at least 1+ with Modified Ashworth Scale
• Patient required botulinum toxin injection at affected upper limb muscle per primary care physician.

[Control group]

• Stroke patients with unilateral involvement
• Patient's spasticity over affected upper extremities scored at least 1+ with Modified Ashworth Scale

Exclusion Criteria:

• Patients ever diagnosed with cerebral diseases other than stroke, such as traumatic brain injury, encephalitis and brain tumor
• Patients failed to cooperated due to cognition, consciousness or speech problem
• Patients with illness that could affect muscle stiffness, such as spinal cord injury and Parkinson's disease
• Patients with upper limb contracture
• Patients receiving botulinum toxin injection or shock wave therapy over upper extremities during past three months

Stroke patient aged above 20 years old with unilateral involvement.