Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Neurological disability
Systematic review	113 adults with cervical dystonia 3 RCTs in this analysis	Improvement of at least 3 points on Tsui scale 3 to 6 weeks 32/56 (57%) with botulinum A toxin 13/57 (23%) with placebo	OR 4.25 95% CI 2.00 to 9.05 P = 0.002 NNT 4 95% CI 3 to 6	Moderate effect size	botulinum A toxin
Systematic review	353 adults with cervical dystonia 6 RCTs in this analysis	Any improvement in Tsui or Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) 0 to 12 weeks 97/174 (56%) with botulinum A toxin 31/179 (17%) with placebo	OR 5.47 95% CI 3.52 to 8.48 P = 0.002	Large effect size	botulinum A toxin
Systematic review	510 adults with cervical dystonia 11 RCTs in this analysis	Any improvement in subjective patient-related scales 0 to 16 weeks 161/273 (59%) with botulinum A toxin 46/237 (19%) with placebo	OR 6.58 95% CI 4.55 to 9.54 P = 0.00001 NNT 3 95% CI 3 to 3	Large effect size	botulinum A toxin
Systematic review	350 adults with cervical dystonia 4 RCTs in this analysis	Physicians reporting improvement 0 to 16 weeks 123/197 (62%) with botulinum A toxin 46/153 (30%) with placebo	OR 4.17 95% CI 2.70 to 6.44 P <0.00001 NNT 3 95% CI 3 to 5	Moderate effect size	botulinum A toxin
Systematic review	162 adults with cervical dystonia 5 RCTs in this analysis	Proportion of people reporting pain relief time frame not reported 60/84 (71%) with botulinum A toxin 9/78 (12%) with placebo	OR 11.92 95% CI 6.32 to 22.5 P <0.00001 NNT 2 95% CI 2 to 3	Large effect size	botulinum A toxin
RCT	116 adults with cervical dystonia	Mean change in TWSTRS-Total score from baseline at week 4 –15.6 with botulinum A toxin –6.7 with placebo	P <0.001 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin