THURSDAY, Dec. 21, 2006 (HealthDay News) -- Already hailed for its wrinkling-erasing properties, Botox is now being touted as an effective treatment for writer's cramp, too.
"This study provides ample evidence for the beneficial effect of Botulinum toxin injections on writer's cramp," said study lead author Dr. Jose Kruisdijk, of the department of neurology at Academic Medical Centre in Amsterdam, the Netherlands.
"The injections with Botulinum toxin can be given by a neurologist or other medical specialist who has gained some experience with this treatment," Kruisdijk added.
Outside experts urged caution. "The study does show some evidence of efficacy, but it's a relatively small study, and it's only one paper, so it's hard to make a generalization," said Dr. Robert A. Weber, associate professor of surgery at Texas A&M Health Science Center College of Medicine and chief of the Section of Hand Surgery at Scott & White Hospital.
Writer's cramp refers to involuntary muscle contractions of the fingers, hand or arm while writing or performing other manual tasks. In one quarter of cases, the condition affects both hands. Overall, writer's cramp affects three to seven of every 100,000 people, a relatively small proportion, but it can negatively affect work, self-esteem and social life, the study authors stated.
Weber had one patient who was a first-chair violinist who watched in horror when her hand drew back and her bow dropped in the middle of a solo. Other patients can only use their hands for a few minutes before the writer's cramp sets in.
There are no effective drugs to treat writer's cramp, and other therapies, including relaxation, hypnosis, biofeedback and acupuncture, have had only limited success.
Botulinum toxin type A is a protein complex produced by the bacterium Clostridium botulinum and contains the same toxin that causes food poisoning. But sterile, purified botulin toxin in small doses also blocks the release of acetylcholine, a chemical produced by nerve cells that signals muscles to contract.
The substance was first approved in 1998 to treat eye problems such as "lazy eye." Next, it got approval from the U.S. Food and Drug Administration for the treatment of a movement disorder that causes neck and shoulder contractions. It is also used to help stroke victims recover some limb function and to help children with cerebral palsy.
For the new study, which appeared online Dec. 20 in the Journal of Neurology, Neurosurgery and Psychiatry, 40 people with writer's cramp were randomly assigned to receive Botox injections or a placebo injection over a period of 12 weeks.
Fourteen of 20 patients (70 percent) receiving Botox reported significant improvement and chose to continue treatment. Only six of 19 patients (31.6 percent) in the placebo group reported improvements and wanted to continue. One person dropped out of the trial.
Participants receiving Botox injections also scored higher on clinical rating scales.
After one year, 50 percent of the original participants were still receiving Botox injections and finding them helpful.
Some participants reported mild hand weakness, but this side effect was generally transitory.
This muscle weakness is one of the main drawbacks of Botox and one of the reasons Weber said he didn't use it. Another drawback is the fact that Botox is not a permanent treatment.
In this study, individuals had relief from writer's cramp for three to 18 months, with an average symptom-free period of four-and-a-half months. The effects of Botox are not permanent and require repeat injections about every three months.
The trial was the largest conducted to date on this topic, the researchers said.
"Our study is the first large double-blind randomized placebo controlled trial regarding the treatment effect of Botulinum toxin on writer's cramp," Kruisdijk said. "Open-label studies and a few small randomized controlled trials were reported before and showed positive results."
And the findings were not surprising to the authors.
"The results were in accordance with our expectations," Kruisdijk said.
More information
To learn more about Botox, visit the U.S. Food and Drug Administration.
