Efficacy of botulinum toxin for cervical dystonia. A comparison of methods for evaluation

Twenty patients with cervical dystonia were treated during one year with repeated intramuscular injections of botulinum toxin. The outcome was evaluated comparing subjective global rating with relative changes in degree of pain on the Visual analogue scale (VAS), degree of dysfunction due to dystonia, and quality of life according to the Nottingham health profile (NHP). Objective measurement of dystonic position and movement ability was performed using a goniometer, semiquantitatively noted as scores according to Fahn and Tsui. Before treatment, the degree of impaired life quality on the NHP did not correlate with the Tsui score of dystonic posture, but significantly with the Fahn score (p < 0.01) which also includes data on pain. Significant improvement after treatment was seen for all parameters (p < 0.05). Global subjective rating correlated significantly with improved posture according to the Tsui score (p < 0.05), but not with reduced pain or degree of dysfunction. The results suggest that the efficacy of botulinum toxin in cervical dystonia is best evaluated using a combination of the VAS for pain and the Tsui score for dystonic posture and movement ability.