Clinical Trial: Botox for Cervical Dystonia Following EMG Mapping

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Pre-injection, Multi-channel EMG Mapping to Optimize Botulinum Toxin Type A Efficacy in Cervical Dystonia.

Brief Summary: The purpose of this study is to determine how to improve treatment of patients with cervical dystonia who have not been helped with standard Botox injections. This study is for patients with cervical dystonia who have not benefited from treatment with Botox using conventional "single lead electromyographic (EMG) techniques" for injection. The study aim is to see if these patients may have significantly more benefit if their Botox is injected into muscles that have been chosen with a multi-channel EMG mapping study of the neck prior to Botox injection.

Detailed Summary:

The most common type of primary late-onset dystonia is cervical dystonia. Botulinum toxin A (BTX-A) injections are a safe and effective treatment for cervical dystonia in a majority of patients, however, a significant minority of patients (between 15 and 25%) have a suboptimal response to Botulinum toxin therapy. It is unclear why some patients do not respond maximally to neurotoxin therapy.

Studies using needle electromyographic "mapping" in the evaluation of cervical dystonia have revealed that clinical examination alone is insufficient for determining which muscles contribute to the dystonic movement. When compared to needle electromyography (EMG) "mapping studies", experienced movement disorders specialists correctly identify only 59% of active muscles and believe that 25% of muscles which upon EMG evaluation are found to be quiescent, are involved in the dystonia. The selection of incorrect muscles for injection of Botulinum toxin may explain why some patients have a sub-optimal response.

This study seeks to measure outcomes when the muscles involved in dystonia are identified using "mapping" via an 8-12 channel EMG. In the proposed study, the most involved/active dystonic muscles will be correctly identified through simultaneous 8-12 channel mapping resulting in a more informed injection strategy, which may improve response to Botulinum toxin A treatment as compared to single lead EMG based injections. This study changes routine clinical care only by adding the step of studying the muscles of the neck with simultaneous EMG mapping to allow a more objective injection strategy.


Sponsor: University of California, San Francisco

Current Primary Outcome:

  • Pre- and Post-injection Toronto Western Spasmodic Torticollis Rating Scale(TWSTRS): Global Clinical Impression Scale (GCI); Visual Analog Scale(VAS) [ Time Frame: pre-injection, week 16, 20, 36, and 40 ]
  • Mean Percentage Change in Total Toronto Western Spasmodic Torticollis Rating Scale [ Time Frame: 48 weeks ]
    Mean Percentage change in Toronto Western Spasmodic Torticollis Rating Scale. This scale ranges from 0 (normal) to 85 (very severe).


Original Primary Outcome: Pre- and post-injection Toronto Western Spasmodic Torticollis Rating Scale: Global Clinical Impression Scale; Visual Analog Scale [ Time Frame: pre-injection, week 16, 20, 36, and 40 ]

Current Secondary Outcome:

Original Secondary Outcome:

Information By: University of California, San Francisco

Dates:
Date Received: October 14, 2008
Date Started: April 2008
Date Completion:
Last Updated: September 9, 2011
Last Verified: September 2011