Botox® (onabotulinumtoxin A, Allergan, Inc.) reduced arm tremor (uncontrollable shaking) and improved arm and fine hand movements and function significantly more than inactive placebo in a study of 23 people with MS. If confirmed in a larger study, this research may yield a new strategy to address this common and disabling symptom of MS, which is often resistant to treatment. Anneke Van Der Walt, MBChB, and colleagues (University of Melbourne, Melbourne, Australia) report their findings in Neurology (2012;79:92-99
). The study was supported by the Box Hill MS Research Fund and The Royal Melbourne Hospital Neuroscience Foundation.
Many people with MS experience some degree of tremor, or uncontrollable shaking. It can occur in various parts of the body. Tremor occurs because there are damaged areas along the complex nerve pathways that are responsible for coordination of movements. To date, there have been no reports of consistently effective medical or exercise treatments for tremor; it is considered by physicians and other health professionals to be one of the most difficult symptoms of MS to treat.
Botox is a powerful neurotoxin that temporarily blocks connections between the nerves and muscles, resulting in short-term relaxation of the targeted muscle. The FDA has approved Botox for treating upper limb muscle spasticity (extreme tightness) and bladder muscle dysfunction in people with MS and other disorders. Botox has shown some benefit in treating tremor in other disorders.
The investigators recruited 23 people with MS who had arm tremor, and randomly assigned them to receive either Botox or inactive placebo (saline) injections for 12 weeks. Each group was then switched to the other treatment for an additional 12 weeks. Before injections began, the investigators assessed tremor patterns to determine the specific arm muscle to inject. Before and after treatment, tremor severity and writing and drawing ability were measured. Participants underwent video assessments as well.
Tremor severity was reduced significantly more with Botox than placebo injections, and writing/drawing ability improved significantly more with Botox as well. Video assessments by an independent observer also revealed significant improvements with Botox treatment.
Mild to moderate arm weakness occurred in 14 people treated with Botox, compared with two receiving placebo. Weakness resolved within two weeks.
The authors conclude that these results provide the framework for a larger, phase III study to confirm the findings. If confirmed, this research may yield a new strategy for addressing an often disabling and treatment-resistant symptom of MS.
Read more about MS-related tremor.
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