Quantitative evaluation of the effects of L-dopa in torsion dystonia: a case report.

We used electrophysiologic methods in the diagnosis of torsion dystonia and the evaluation of therapy in a 7-year-old child. Electromyographic (EMG) activity patterns in five leg muscles were recorded during specific voluntary and passive movements as well as during gait. We found patterns of coactivation in leg muscles in walking or isolated movements, and a shortening reaction was seen in the tibialis anterior. These findings in combination with clinical observations led to the diagnosis of torsion dystonia and the choice of L-dopa therapy. Beneficial effects of therapy were assessed by the same methods.