Objective
The purpose of this study is to evaluate the effects of intramuscular botulinum toxin A injection for the improvement of hand function in spastic hemiplegia.

Method
We have studied 8 patients with spastic hemiplegia. Botulinum toxin A was injected into target muscles with electromyographic guidance. Before injection, muscle activity patterns were evaluated by dynamic electromyography. Follow-up assessments were performed at three months after injection.

Results
There were continuous activity patterns in all dynamic electromyography of target muscles. Dynamic electromyography of antagonist muscles in five patients showed normal phasic activity pattern but it showed absent pattern in other three patients. Mean modified Ashworth scale decreased significantly after injection. There were an improvement in functional classification and a significant increase of mean scores of unilateral hand skills after injection in patients with normal phasic pattern of antagonist muscles.

Conclusion
Botulinum toxin A can improve the impaired hand movement and function in spastic hemiplegia by reducing spasticity and contracture of the target muscles in cases of normal phasic activity in antagonist muscles and continuous activity in target muscles.