Botulinum toxin in writer's cramp: objective response evaluation in 31 patients.

OBJECTIVES: To quantify the treatment effect of local botulinum toxin injections in writer's cramp a newly developed rating scale of writing performance and a computer assisted analysis of writing speed were used in 31 patients undergoing botulinum toxin therapy. METHODS: Baseline data of the writer's cramp rating scale (WCRS, see appendix) and computer based writing speed analysis were compared with those obtained at the time of subjective best response as recorded during follow up visits. RESULTS: The mean dose injected per session was 133.2 units Dysport divided between two forearm muscles. Of all 124 injection sessions during mean follow up of one year 76% produced a good improvement. The most common side effect was weakness (72% of the follow up visits). The WCRS scores as assessed by a blinded videotape review by four independent raters showed good reliability between raters and a significant improvement after treatment (P < 0.001). The speed of pen movements showed a significant (P < 0.05) increase after treatment at subjective best effect recordings and a significant correlation with WCRS subscores, documenting the validity of the scale. CONCLUSION: The present study is the first to show significant effects of botulinum toxin treatment in patients with writer's cramp on the basis of a quantifiable scale for writing performance which correlates significantly with writing speed measurements. The WCRS as employed in this study might therefore prove a useful rating instrument in other studies assessing severity and treatment response in patients with writer's cramp.

GAG deletion in the DYT1 gene in early limb-onset idiopathic torsion dystonia in Germany.

We examined 57 patients with idiopathic torsion dystonia (ITD) for the 3-bp GAG deletion in the DYT1 gene on human chromosome 9q34. Three of five patients with early limb-onset ITD, one of them with a positive family history, tested positive for the mutation, as did one young patient with multifocal dystonia and a short course of the disease. Two patients with early-onset generalized dystonia beginning in the cervical muscles, as well as five other patients with multifocal, 14 patients with segmental, and 30 patients with focal cervical dystonia did not carry the mutation. This suggests that the GAG deletion is responsible for a major portion of cases of typical early limb-onset dystonia, but not for other types of dystonia, in our population.

What is the optimal dose of botulinum toxin A in the treatment of cervical dystonia? Results of a double blind, placebo controlled, dose ranging study using Dysport. German Dystonia Study Group.

OBJECTIVES: Botulinum toxin injections have become a first line therapeutic approach in cervical dystonia. Nevertheless, published dosing schedules, responder rates, and frequency of adverse events vary widely. The present prospective multicentre placebo controlled double blind dose ranging study was performed in a homogenous group of previously untreated patients with rotational torticollis to obtain objective data on dose-response relations. METHODS: Seventy five patients were randomly assigned to receive treatment with placebo or total doses of 250, 500, and 1000 Dysport units divided between one splenius capitis (0, 175, 350, 700 units) and the contralateral sternocleidomastoid (0, 75, 150, 300 units) muscle. Assessments were obtained at baseline and weeks 2, 4, and 8 after treatment and comprised a modified Tsui scale, a four point pain scale, a checklist of adverse events, global assessment of improvement, and a global rating taking into account efficacy and adverse events. At week 8 the need for retreatment was assessed and then the code was unblinded. For those still responding, there was an open follow up until retreatment to assess the duration of effect. RESULTS: Seventy nine per cent reported subjective improvement at one or more follow up visits. Decreases in the modified Tsui score were significant at week 4 for the 500 and 1000 unit groups versus placebo (p<0.05). Additionally positive dose-response relations were found for the degree of subjective improvement, duration of improvement, improvement on clinical global rating, and need for reinjection at eight weeks. A significant dose relation was also established for the number of adverse events overall and for the incidence of neck muscle weakness and voice changes. CONCLUSION: Magnitude and duration of improvement was greatest after injections of 1000 units Dysport; however, at the cost of significantly more adverse events. Therefore a lower starting dose of 500 units Dysport is recommended in patients with cervical dystonia, with upward titration at subsequent injection sessions if clinically necessary.