Utility of an EMG mapping study in treating cervical dystonia

Intramuscular injections of botulinum toxin are the cornerstone of treatmen t for cervical dystonia. Controversy exists regarding the necessity for EMG -guided injections. We compared the clinical examination of four movement d isorder specialists to an electromyographic (EMG) mapping study. Clinical p redictions of individual muscle involvement were only 59% sensitive and 75% specific. Muscle hypertrophy, shoulder elevation, and dominant head vector did not bolster clinical accuracy. An EMG mapping study facilitates identi fication of dystonic muscles in cervical dystonia, which may enhance botuli num toxin therapy. (C) 2000 John Wiley & Sons, Inc.