Clinical and Electrophysiological Investigations of Changes in Muscle Activation Patterns Before and After Botulinum Toxin Injections for Idiopathic Cervical Dystonia

Objective: To evaluate the electromyographic activation of cervical muscles before and after botulinum toxin injections and to investigate the distribution patterns of dystonia that may occur in other muscles during the disease in Cervical Dystonia (CD) patients with no history of previous Botulinum Toxin (BT) injections. Method: Newly diagnosed 9 idiopathic CD patients, who have not been previously injected with BT, are included. After the recruitment of the participants into the study, clinical [Toronto Western Spazmodic Torticollis Evaluation Scale (TWSTRS)] and electrophysiological evaluation [4 pairs of muscles (sternocleidomastoid (SCM), splenius capitis (SC), trapezius (TRA), levator scapulae (LS), a total of 8 EMG sessions for each patient] were carried out in pre- and post-injection period every 6 weeks. BT was performed every 12 weeks (a total of 4 sessions). Results: No permanent change in bioelectrical activity was stated in comparative evaluation of the muscles at the end of the 1-year follow-up. 88.8% of the patients showed subjective amelioration. According to TWSTRS, average 13.36% amelioration was observed. Statistically significant positive correlation was detected between subjective benefit and values of clinical scale (TWSTRS). Discussion: This study is the first in the literature to investigate the changes of muscle activation patterns in CD patients after the BT injections with serial EMG studies, One year follow-up may be thought as a short follow-up period for talking about a permanent change of the muscle activity. In addition to mathematical evaluations, clinical experience and observations are very important; a subjective benefit reported by patients is also reasonably meaningful. (Archives of Neuropsychiatry 2009; 46: 39-43)