Objective
To evaluate the change of abnormal spontaneous activities according to the clinical and radiologic findings, and to the time course after onset in hemiplegic upper limb.

Method
We scored abnormal spontaneous activities of hemiplegic upper limb muscles (infraspinatus, deltoid, extensor carpi radialis, abductor pollicis brevis, abductor digiti minimi) in 100 hemiplegic patients without peripheral neuropathy. The abnormal spontaneous activities were evaluated according to their radiologic findings and to Brunnstrom stage and the presence of reflex sympathetic dystrophy (RSD), and the time course after the onset (A cross-sectional study). In addition we repeatedly examined 40 hemiplegic patients until 12 weeks after the onset to define the pattern of change (A prospective study).

Results
There was no significant difference in the score of abnormal spontaneous activities according to the radiologic findings. The score of abnormal spontaneous activities decreased while Brunnstrom stage progressed. In both the cross-sectional and prospective studies, we found that the abnormal spontaneous activities decreased according to the time course after the onset in the limb without RSD, but sustained in the limb with RSD.

Conclusion
Abnormal spontaneous activities decreased according to the progression of Brunnstrom stages. The hemiplegic patients with RSD showed more profuse and sustained abnormal spontaneous activities at needle EMG study of hemiplegic upper limb than the patients without RSD.