Botulinum toxin treatment of tremors.

We report the results of an open trial of botulinum toxin (Botox) in the treatment of 51 patients with disabling tremors, classified as dystonic (14), essential (12), combination of dystonic and essential (22), parkinsonian (1), peripherally induced (1), and midbrain (1). The average age of the patients was 55.8 years, and duration of symptoms was 13.9 years. During a total of 160 treatment visits, an average of 242 +/- 75 units of Botox was injected per visit in cervical muscles of 42 patients with head tremor and 95 +/- 38 in forearm muscles of 10 patients with hand tremor; one patient was injected in both. The average peak effect for all patients was rated as 3.0 (0 to 4 scale). Thirty-five (67%) patients improved (peak effect greater than or equal to 1). The average latency from injection to response was 6.8 days, and the average duration of maximum improvement was 10.5 weeks. Local complications, lasting an average of 20.6 days, were noted in 17 (40%) patients injected for head tremor, consisting chiefly of dysphagia in 12 (29%), transient neck weakness in four (10%), and local pain in two (5%). Six (60%) patients with hand tremor had transient focal weakness. EMG recordings showed decreased amplitude of EMG bursts after Botox treatment. The results of this pilot study indicate that Botox injections can be used to control tremor in patients in whom other forms of therapy have failed.