BACKGROUND: The value of physical examination in detecting involved neck muscles in cervical dystonia (CD) is uncertain and little is known about changes in electromyographic (EMG) features after botulinum toxin type A (BTA) treatment. METHODS: In a double-blind, randomized study we recorded the EMG activities of 420 neck muscles in 42 patients with CD before and after treatment withBTA or trihexyphenidyl. We regarded any needle EMG activity higher than 100 microV as the gold standard for involuntary involvement of a muscle in the dystonic posture and compared this with the results of physical examination. We calculated EMG total scores by adding the scores of the individual muscles. RESULTS: Physical examination had a low predictive value in the detection of involved muscles. There was a significant correlation between changes in EMG total scores and changes in clinical measurements. We observed increased EMG activity in 20% of noninjected muscles after BTA treatment and in 27% of noninjected muscles after trihexyphenidyl treatment. A switch from one most active muscle to another was seen equally in both groups and had no influence on clinical response. CONCLUSION: Physical examination alone is not sufficient to detect involved muscles, and repeated, simultaneous EMG-guided application of BTA may be helpful. In addition to clinical measurements, changes in EMG activity due to treatment can be used as a physiologic measure in evaluating treatment response. Increased activity of noninjected muscles and a switch from one most active muscle to another are not related to BTA treatment, but are probably pathophysiologic phenomena of CD itself.
RCT Entities:
BACKGROUND: The value of physical examination in detecting involved neck muscles in cervical dystonia (CD) is uncertain and little is known about changes in electromyographic (EMG) features after botulinum toxin type A (BTA) treatment. METHODS: In a double-blind, randomized study we recorded the EMG activities of 420 neck muscles in 42 patients with CD before and after treatment with BTA or trihexyphenidyl. We regarded any needle EMG activity higher than 100 microV as the gold standard for involuntary involvement of a muscle in the dystonic posture and compared this with the results of physical examination. We calculated EMG total scores by adding the scores of the individual muscles. RESULTS: Physical examination had a low predictive value in the detection of involved muscles. There was a significant correlation between changes in EMG total scores and changes in clinical measurements. We observed increased EMG activity in 20% of noninjected muscles after BTA treatment and in 27% of noninjected muscles after trihexyphenidyl treatment. A switch from one most active muscle to another was seen equally in both groups and had no influence on clinical response. CONCLUSION: Physical examination alone is not sufficient to detect involved muscles, and repeated, simultaneous EMG-guided application of BTA may be helpful. In addition to clinical measurements, changes in EMG activity due to treatment can be used as a physiologic measure in evaluating treatment response. Increased activity of noninjected muscles and a switch from one most active muscle to another are not related to BTA treatment, but are probably pathophysiologic phenomena of CD itself.
Authors: Maria Fiorella Contarino; Joost Van Den Dool; Yacov Balash; Kailash Bhatia; Nir Giladi; Johannes H Koelman; Annemette Lokkegaard; Maria J Marti; Miranda Postma; Maja Relja; Matej Skorvanek; Johannes D Speelman; Evelien Zoons; Joaquim J Ferreira; Marie Vidailhet; Alberto Albanese; Marina A J Tijssen Journal: Front Neurol Date: 2017-02-24 Impact factor: 4.003
Authors: Filipe B Rodrigues; Gonçalo S Duarte; Mafalda Castelão; Raquel E Marques; Joaquim Ferreira; Cristina Sampaio; Austen P Moore; João Costa Journal: Cochrane Database Syst Rev Date: 2021-04-14
Authors: Joseph Jankovic; Charles H Adler; P David Charles; Cynthia Comella; Mark Stacy; Marc Schwartz; Susan M Sutch; Mitchell F Brin; Spyridon Papapetropoulos Journal: BMC Neurol Date: 2011-11-04 Impact factor: 2.474