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 3–6 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 Scale or Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) 0–12 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 0–16 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 0–16 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
RCT 3-armed trial	233 adults with cervical dystonia	Mean change in TWSTRS-Total score from baseline at week 4 –9.9 with incobotulinumtoxinA (120 U) –2.2 with placebo	Adjusted mean difference –7.5 95% CI –10.4 to –4.6 P <0.001 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin
RCT 3-armed trial	233 adults with cervical dystonia	Mean change in TWSTRS-Total score from baseline at week 4 –10.9 with incobotulinumtoxinA (240 U) –2.2 with placebo	Adjusted mean difference –9.0 95% CI –12.0 to –5.9 P <0.001 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin
RCT 3-armed trial	233 adults with cervical dystonia	Mean change in TWSTRS-Total score from baseline at week 8 –6.9 with incobotulinumtoxinA (120 U) +0.4 with placebo	Adjusted mean difference –7.1 95% CI –10.1 to –4.2 P <0.001 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin
RCT 3-armed trial	233 adults with cervical dystonia	Mean change in TWSTRS-Total score from baseline at week 8 –8.2 with incobotulinumtoxinA (240 U) +0.4 with placebo	Adjusted mean difference –8.6 95% CI –11.5 to –5.8 P <0.001 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin
RCT 3-armed trial	233 adults with cervical dystonia	Mean change in TWSTRS-Total score from baseline up to 20 weeks –3.6 with incobotulinumtoxinA (120 U) +1.7 with placebo	Adjusted mean difference –5.2 95% CI –7.4 to –3.0 P <0.001 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin
RCT 3-armed trial	233 adults with cervical dystonia	Mean change in TWSTRS-Total score from baseline up to 20 weeks –4.6 with incobotulinumtoxinA (240 U) +1.7 with placebo	Adjusted mean difference –6.4 95% CI –8.6 to –4.2 P <0.001 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin
RCT	170 adults with cervical dystonia and who previously responded to onabotulinumtoxinA injections; see further information on studies	Cervical Dystonia Severity Scale (CDSS) at week 6 Mean –1.81 points with known responders to onabotulinumtoxinA Mean –0.31 points with placebo	P = 0.012 Intention-to-treat analysis	Effect size not calculated	botulinum A toxin
RCT	170 adults with cervical dystonia and who previously responded to onabotulinumtoxinA injections; see further information on studies	Improved Physician Global Assessment Scale scores at week 6 62% with known responders to onabotulinumtoxinA 42% with placebo	P = 0.022	Effect size not calculated	botulinum A toxin