Evaluation of the effect of treatment on movement disorders in astrocytomas of the basal ganglia and the thalamus.

Twenty patients with movement disorders associated with astrocytomas (grade I-IV according to the WHO tumour classification) of the basal ganglia and the thalamus were evaluated for the effects of treatment. Five patients had more than one movement disorder when the histological diagnosis was verified by stereotactic biopsy. Twelve had tremors, eight hemidystonia, three hemichorea, and one hemichorea/ballismus, and myoclonus respectively. Ten patients died during the follow up period, and for the surviving patients follow up periods ranged from 6-21 years. The movement disorders changed over long periods of time related to therapeutic interventions. CSF shunt operations and percutaneous radiotherapy had no definite effect on the movement disorders. There was a moderate response to medical treatment in a few patients. Stereotactic aspiration of tumour cysts had a marked influence on the movement disorder in two patients, and functional stereotactic surgery abolished tumour induced tremor in one. Interstitial radiotherapy was performed in fifteen patients for treatment of the underlying neoplasm and resulted in different and variable alterations of the movement disorders. These differences may be explained by complex interactions involving structures affected primarily by the tumour, as well as by secondary functional lesions of adjacent structures.