"Botox"' the popular anti- wrinkle treatment, can also ease writer's cramp, suggests a small study published ahead of print in the Journal of Neurology Neurosurgery and Psychiatry.
Writer's cramp describes the painful involuntary, spasmodic muscle contractions of the fingers, hand, or arm during writing. But it can also occur during other manual tasks.
Some people learn to write with their other hand, but in one in four cases, the condition affects both hands, and the condition is difficult to treat. It affects around three to seven in every 100,000 people.
Relaxation techniques, hypnosis, biofeedback, acupuncture, and 'writing re-education exercises' have all been used, but none of these brings sustained relief. And there is as yet no effective drug treatment.
Forty people with writer's cramp were randomly assigned to a course of injections containing either botulinum toxin (botox) or a dummy substitute in two doses, usually into two muscles, over a period of 12 weeks.
Of the 20 people given botox treatment, 14 (70%) said that their condition had significantly improved, and that they wished to continue treatment. Their improvement was confirmed using validated disability and pain scales.
Only six of the 19 people in the dummy group felt that their condition had improved. One person dropped out of the trial.
One person who received the dummy injection at the first session and botox at the second, also registered an improvement in symptoms.
After a year, half of the trial participants were still receiving botox injections, and were finding them helpful.
Side effects included mild and temporary muscle weakness and pain at the injection site. Symptom relief lasted from three to 18 months, with an average symptom free period of four and a half months.