Therapeutic application of Botulinum Toxin A in patients with local muscle dystonia and oral dyskinesia

Abstract

Botulinum Toxin Type A has been introduced as new therapeutic regime in neurological, cosmetic, urinary, gastrointestinal and pain-related conditions. The use of Botulinum Toxin A in craniomandibular disorders is discussed controversially. Local muscle dystonia is defined as movement disorder in combination with sustained muscle contractions. Contortion, repetitive movements and atypical posture are frequently seen symptoms in such cases. The movements are involuntary and often painful. A single muscle or a group of muscles, even the whole body may be involved. Oral dyskinesias are involuntary repetitive movements of the mouth and face. Severe bruxism can be included in this form of movement disorder. Within this study, patients diagnosed with severe bruxism or local muscle dystonia including oral dyskinesia were examined with electromyography before and after treatment. Subjects were randomly allocated to either myo-relaxation medication and relaxation splint therapy or to Botulinum Toxin A injection therapy. Surface EMG parameters of chewing and neck muscles were used to judge the treatment effects. A positive impact of BTA on EMG-characteristics, reflecting the functional condition of facial muscles, had been detected. BTA injections seem to have a positive effect in patients with bruxism and local muscle dystonia. An increased quantity of mandibular movements and a better coordination can be observed after BTA injection. In comparison with a standard myo relaxation therapy, the effects of BTA treatment are more distinct and long standing. BTA appears to be a promising therapeutic regime in patients with focal muscle dystonia and oral dyskinesia. A confirmed diagnosis and lege artis application by experienced clinicians constitute as sine qua non. Further studies are required to improve our knowledge in Botulinum Toxin A treatment of muscle dystonia and dyskinesia.