Writer's cramp: is focal dystonia the best explanation?

A unifying motor control framework for task-specific dystonia

Task-specific dystonia is a movement disorder characterized by a painless loss of dexterity specific to a particular motor skill. This disorder is prevalent among writers, musicians, dancers and athletes. No current treatment is predictably effective, and the disorder generally ends the careers of affected individuals. Traditional disease models of dystonia have a number of limitations with regard to task-specific dystonia. We therefore discuss emerging evidence that the disorder has its origins within normal compensatory mechanisms of a healthy motor system in which the representation and reproduction of motor skill are disrupted. We describe how risk factors for task-specific dystonia can be stratified and translated into mechanisms of dysfunctional motor control. The proposed model aims to define new directions for experimental research and stimulate therapeutic advances for this highly disabling disorder.

[Experience of botulinum toxin in treatment of writer's cramp]

OBJECTIVE

To evaluate the efficacy and safety of botulinum toxin type A (BTA) injections in patients with writer's cramp (WC).

MATERIAL AND METHODS

We treated 29 patients, in general, 49 BTA injections were performed. To determine points for the injections, we used ultrasound examination of the forearm including the time of writing.

RESULTS

Patients reported subjective improvement in 75.9% after the first injection. Positive results as assessed with the WCRS were seen in 82.7% of the patients. We observed muscle weakness in the hands of 17.2% of the patients. Most of the patients were satisfied with the result of the injection and agreed on the need to re-injection when clinical effect of BTA had decreased.

CONCLUSION

To determine the indications for BTA injections in PS, an individual approach to the development of schemes of injections and calculation of dose is needed. Treatment of BTA should be used in severe forms of WC with social significance to the patients.