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ANA: Botulinum Toxin Type B Does Not Help Gait Freezing in Parkinson's Patients By Jill Stein SAN FRANCISCO, CA -- October 24, 2003 -- Botulinum toxin type B does not significantly improve freezing of gait (FOG) in patients with Parkinson's disease (PD), investigators announced on October 19th here at the 128th Annual Meeting of the American Neurological Association. Freezing of gait is a common and disabling symptom in PD that is often refractory to medical treatment. Hubert H. Fernandez, MD, and associates at Brown University, Providence, Rhode Island, United States, presented results in 14 patients with idiopathic PD who were enrolled in a double blind, placebo-controlled study using botulinum toxin type B injections for FOG. Subjects received either normal saline injections (n=5) or intramuscular injections of 5,000 units of botulinum toxin type B to the soleus-gastrocnemius complex of the predominantly affected leg (n=9). Anti-PD medications were kept constant throughout the study. Based on the Clinical Global Impressions Scale, 1 patient was markedly improved, and 2 patients had minimal improvement. Nine patients were unchanged from baseline, and 2 patients were slightly worse. The treatment and placebo groups did not differ in the number of patients improved versus unchanged, nor were there any differences between the 2 groups in the Unified Parkinson's Disease Rating Scale II and III, Visual Analogue Score, or Modified Webster Step-Seconds scores between the treatment and placebo arms, at baseline and after treatment. Two patients had dry mouth, and 1 patient had increased festination. Although double blind, the study had several weaknesses, Dr. Fernandez said. First, the sample size was small, and the study may have been insufficiently powered to detect a small but significant beneficial effect of botulinum toxin type B. Also, the study used only a single injection of botulinum toxin type B, and the appropriate dose is not known. "We chose the 5,000-unit dose based on the reported approximate botulinum toxin type A to B ratio of 1:50, whereas 125 units of botulinum toxin type A improved freezing of gait in a single case report," Dr. Fernandez noted. "Higher doses may have improved freezing of gait symptoms," he added. Also, the researchers did not perform botulinum toxin type B injections under electromyographic guidance, although it would probably be difficult to miss the soleus-gastrocnemius complex. And, finally, it is not known whether injection of the soleus-gastrocnemius is adequate, and whether injection of both legs would be more effective than injection in 1 leg. Dr. Fernandez said that future double blind dose-ranging studies are needed to determine whether botulinum toxin type B has a role in FOG in PD. Since leg weakness was not noted in any participant, higher doses, injecting both legs and/or including opposing muscles in the anterior compartment of the leg (as may be done in botulinum treatment of limb dystonia), should be considered in future studies. [Study Title: Botulinum Toxin Type B for Gait Freezing in Parkinson's Disease. Poster 7] SOURCE: Doctor's Guide (press release) http://tinyurl.com/smnq * * * ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn