Botox for Cervical Dystonia Following EMG Mapping

Condition(s) targeted: Cervical Dystonia

Intervention: Botulinum toxin A (Drug)

Phase: Phase 4

Status: Recruiting

Sponsored by: University of California, San Francisco

Overall contact:
Jamie Grace, B.S., Phone: 415-353-8328, Email: jamie.grace@ucsf.edu

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.

Official title: Pre-Injection, Multi-Channel EMG Mapping to Optimize Botulinum Toxin Type A Efficacy in Cervical Dystonia.

Study design: Treatment, Randomized, Open Label, Crossover Assignment, Efficacy Study

Primary outcome: Pre- and post-injection Toronto Western Spasmodic Torticollis Rating Scale(TWSTRS): Global Clinical Impression Scale (GCI); Visual Analog Scale(VAS)

Detailed description: 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.

Minimum age: 18 Years. Maximum age: 75 Years. Gender(s): Both.

Criteria:

Inclusion criteria:

- Male or female subjects, 18 to 75 years of age.

- Ability to follow study instructions and complete all required visits.

- Subject meets diagnostic criteria for idiopathic primary cervical dystonia.

- Subject has at least moderate severity Cervical Dystonia, with a baseline rating of at

least 30 on the total TWSTRS and at least 15 on the TWSTRS motor severity subsection.

- Patients have had a suboptimal response to 2 previous Botulinum toxin injections at an

outside facility.

- Patients will not have received Botulinum toxin within 16 weeks of the start of the

study.

- In order to not confound the clinical response to BTX-A injections, all patients

enrolled must have been on a stable medication regimen for 30 days. If they are not on medication at the initiation of the study, they will not be started on medication. Patients must be on the same medication regimen through the entire study including assessment of both single lead EMG based injections and "mapping" based injections. Medications cannot be stopped during the study to avoid confounding the clinical response to BTX-A.

Exclusion Criteria:

- Known allergy or sensitivity to any of the components in BTX-A.

- Uncontrolled clinically significant medical condition other than the condition under

evaluation

- Females with a positive pregnancy test, or who are breast-feeding, planning a

pregnancy during the study, who think that they may be pregnant at the start of the study or females of childbearing potential who are unable or unwilling to use a reliable form of contraception during the study.

- Participation in another medication or device study or within 3 months of enrollment

in this study.

- Patients know to have a positive frontalis test or have previously tested positive for

the presence of BTX-A antibodies will be excluded.

- Any known evidence of cervical contractures or significant spinal deformity.

Jamie Grace, B.S., Phone: 415-353-8328, Email: jamie.grace@ucsf.edu

University of California, San Francisco, San Francisco, California 94143, United States; Recruiting
Jamie Grace, B.S., Phone: 415-353-8328, Email: jamie.grace@ucsf.edu
Graham A. Glass, M.D., Phone: 415-221-4810, Ext: 2657, Email: graham.glass@ucsf.edu
Graham A. Glass, M.D., Principal Investigator

San Francisco Veterans Administration Medical Center, San Francisco, California 94121, United States; Recruiting
Susan Heath, M.S.N., Phone: 415-221-4810, Ext: 2505, Email: Susan.Heath@va.gov

Starting date: April 2008
Ending date: October 2010
Last updated: October 22, 2008