This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
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 µV 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.
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
Letters: Rapid online correspondence
REQUIREMENTS
You must ensure that your Disclosures have been updated within the previous six months. Please go to our Submission Site to add or update your Disclosure information.
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
You May Also be Interested in
Alert Me
Recommended articles
Human response to botulinum toxin injection: Type B compared with type A
Management of cervical dystonia with botulinum neurotoxins and EMG/ultrasound guidance
Botulinum toxin versus trihexyphenidyl in cervical dystonia
Comparison of efficacy and immunogenicity of original versus current botulinum toxin in cervical dystonia