NEW YORK, Aug 29 (Praxis Press). Botulinum toxin A (BTX) is an effective treatment for an increasing number of conditions characterized by abnormal muscle contractions. However, its safety and efficacy in the treatment of tics in patients with Tourette syndrome (TS) has not been well studied. To evaluate BTX for this purpose, Kwak and colleagues studied 35 patients (30 male, 5 female) by injecting them with BTX in the sites of their most problematic tics. They evaluated the response to BTX based on a 0 to 4 clinical rating scale (0, no improvement, to 4, marked improvement in both severity and function). In addition, questionnaires were administered to evaluate patients' impressions of overall efficacy and degree of benefit with premonitory sensations. They found that 21 out of 25 patients with premonitory sensations derived marked relief of these symptoms. They also found that the mean peak-effect response in 35 patients treated in 115 sessions was 2.8 (range, 0–4); the mean duration of benefit was 14.4 weeks (maximum, 45 weeks); and the mean latency to onset of benefit was 3.8 days. Botulinum toxin A injections are an effective and well-tolerated treatment of tics and provide relief of premonitory sensations in addition to improving the motor component of tics.