Twenty patients with torticollis had electromyographic studies of their neck muscles performed before and after a series of local injections of botulinum toxin. The pattern of muscle activity changed after the injections, and this effect persisted even after head position had returned to baseline. Patients who did not experience any clinical benefit from the injections also demonstrated a change in the pattern of muscle activity. These results suggest that the underlying abnormality in torticollis usually involves a general motor program for head position, rather than the activity of individual neck muscles.

We investigated the effectiveness of botulinum toxin in 17 patients with limb dystonias (10 with occupational cramps, three with idiopathic dystonia unrelated to activity, and two each with post-stroke and parkinsonian dystonia) in a placebo-controlled, blinded study. We identified affected muscles clinically and by recording the EMG from implanted wire electrodes at rest and during performance of tasks that precipitated abnormal postures. There were three injections given with graded doses of toxin (average doses, 5 to 10, 10 to 20, and 20 to 40 units per muscle) and one with placebo, in random order. Subjective improvement occurred after 53% of injections of botulinum toxin, and this was substantial in 24%. Only one patient (7%) improved after placebo injection. Subjective improvement occurred in 82% of patients with at least one dose of toxin, lasting for 1 to 4 months. Response rates were similar between clinical groups. Objective evaluation failed to demonstrate significant improvement following treatment with toxin compared with placebo. The major side effect was transient focal weakness after 53% of injections of toxin.

The effectiveness of botulinum toxin injections in 11 patients with hemifacial spasm was investigated in a prospective placebo-controlled blinded study. The patients were treated with four sets of injections to various facial muscles, selected by clinical evaluation. Three injections were with graded doses of toxin and one was with placebo. The order of injections was random and unknown to the patients. Results were scored both subjectively by patient assessment of symptoms and objectively by blinded review of videotapes made one month after each injection. Subjective improvement occurred after 79% of injections with botulinum toxin, regardless of dose of toxin. Only 1 patient improved after placebo. Objective improvement was seen after 84% of injections with botulinum toxin. No patient showed objective improvement after placebo injection. The most frequent side effect was facial weakness, seen after 97% of injections of botulinum toxin. Facial bruising (20%), diplopia (13%), ptosis (7%), and various other mild side effects were seen less frequently. Botulinum toxin appears to be an effective and safe method of therapy for hemifacial spasm.