The use of botulinum toxin type A (BoNT/A) as an adjunctive treatment modality for phonic tics on a series of 30 patients affected with tourette's syndrome (TS)

Abstract

Introduction: Tics are the most important feature of Tourette's Syndrome (TS), and, together with a very variable comorbidity, can determine a significant social impairment. Although tic expression can be very variable, drug therapy has shown to be beneficial in a significant amount of patients. Botulinum toxin type A (BoNT/A) is nowadays used to treat a large variety of abnormal muscle tone disorders and cholinergic gland dysfunction, among which an ameliorating effect over TS has been documented. Material and methods: We assessed the effect of BoNT/A on phonic tics in patients affected with TS, refractory to conservative drug therapy with the currently accepted medications. A detailed informed consent was given to the patients prior to the procedure. A total number of 70 patients (29 children aged 10–16 and 41 adults aged 19–55) were included in this prospective, non-randomized study protocol, receiving 2.5 IU BoNT/A (Botox, Allergan) in both vocal cords, under EMG guidance. All the patients were assessed post-procedurally after 15 days and then 4 times over a 12-months period. At each endpoint, the following data were collected: global impression of change (CGI scale), tics phenomenology, number of injections performed, interval between injections, time and duration of response, presence and duration of side effects (mainly hypophonia), presence of premonitory sensations of the tics, and interference of the tics with the normal social functioning of the patient. Results: Phonic tics improved at the CGI scale in 66 patients (94%), 30 (41%) being completely tic-free, while a certain degree of improvement of the overall clinical picture of TS was present in all the patients. Average time before improvement was 4.2 days (SD 2), while average duration of improvement was 82 days (SD 14). Quality of life in terms of social integration improved for all the patients and a subjective diminution of premonitory sensations was also reported by the patients. Hypophonia was documented in 59 (84%) patients and its duration ranged 15–48 days. No major side effect was documented. Conclusions: An extremely disabling feature of TS as phonic tics in which resistance to conventional conservative drug therapy has been documented can to our experience be addressed with BoNT/A. Botulinum toxin injection should be used more extensively in the treatment of TS in that it specifically addresses the involved apparatus, thus avoiding systemic side effects. Reduction of premonitory sensations also indicates that modifications in sensory triggers can be of great interest in order to obtain a better knowledge of the pathophysiological mechanism of phonic tics.