The Role of Clinical and Electrophysiological Evaluations in the Planning of Botulinum Toxin Therapy in Cervical Dystonia

Abstract

Scientific Background: lntramuscular injections of botulinum toxin (BTX) are the most effective treatment for cervical dystonia (CD). The success of BTX treatment in CD is related to the precise identification of dystonic muscles and the accurate placement of toxin. The basic approach in planning and application of BTX treatment in CD is clinical examination. Despite making precise identification of dystonic muscles possible, electromyography (EMG), as an expensive and time consuming approach, has not been used routinely. Objectives: The aim of the present study is to detect the ratio of correct determination of dystonia by clinical examination in muscles that are shown to be dystonic by EMG. Material and Methods: We compared the data obtained from the clinical predictions of dystonic muscles by 4 clinicians and the data obtained from multichannel EMG recordings in 17 patients with CD. Results: Our data indicated that approximately 60%of dystonic muscles would not be recognized and nearly 24%of inactive muscles would be judged as dyst onic by clinical evaluation. Especially the dystonic activity msuperfıcıal and well known muscle groups was detected easily by the clinicians, but the role of deeply located muscles in CD was underlooked. Conclusions: As a conclusion, the present study demonstrated the important role of EMG in identification of the dystonic muscles which can not be determined by clinical examination.