Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Neurological disability
Systematic review	122 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-total score >20 and TWSTRS-severity >10 Data from 1 RCT	Improvement of at least 20% of TWSTRS-total score 4 weeks 60/92 (65%) with botulinum B toxin 8/30 (27%) with placebo	OR 4.69 95% CI 2.06 to 10.69 P = 0.0002 NNT 3 95% CI 2 to 6	Moderate effect size	botulinum B toxin
Systematic review	122 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 Data from 1 RCT	Improvement of at least 20% of TWSTRS-total score 8 weeks 40/92 (43%) with botulinum B toxin 5/30 (17%) with placebo	OR 3.13 95% CI 1.34 to 7.34 P = 0.0008	Moderate effect size	botulinum B toxin
Systematic review	122 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score <20 and TWSTRS-severity <10 Data from 1 RCT	Improvement of at least 20% of TWSTRS-total score 12 weeks 23/92 (25%) with botulinum B toxin 3/30 (10%) with placebo	OR 2.43 95% CI 0.89 to 6.61 P = 0.08		Not significant
Systematic review	122 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 Data from 1 RCT	Improvement of at least 20% of TWSTRS-total score 16 weeks 12/92 (13%) with botulinum B toxin 2/30 (7%) with placebo	OR 1.86 95% CI 0.51 to 6.75 P = 0.3		Not significant
Systematic review	150 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 2 RCTs in this analysis	Patient global assessment of change in symptoms 0–4 weeks with botulinum B toxin (10,000 U) with placebo Absolute results not reported	WMD 20.04 95% CI 14.22 to 27.45 P <0.00001	Effect size not calculated	botulinum B toxin
Systematic review	72 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 Data from 1 RCT	Patient global assessment of change in symptoms 0–4 weeks with botulinum B toxin (5000 U) with placebo Absolute results not reported	WMD 17.00 95% CI 6.93 to 27.07 P <0.0009	Effect size not calculated	botulinum B toxin
Systematic review	150 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 2 RCTs in this analysis	Principal investigator global assessment of change in symptoms 0–4 weeks with botulinum B toxin (10,000 U) with placebo Absolute results not reported	WMD 12.52 95% CI 7.97 to 17.08 P <0.00001	Effect size not calculated	botulinum B toxin
Systematic review	72 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 Data from 1 RCT	Principal investigator global assessment of change in symptoms 0–4 weeks with botulinum B toxin (5000 U) with placebo Absolute results not reported	WMD 13.30 95% CI 5.50 to 21.50 P = 0.001	Effect size not calculated	botulinum B toxin
Systematic review	150 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 2 RCTs in this analysis	Patient analogue pain assessment 0–4 weeks with botulinum B toxin (10,000 U) with placebo Absolute results not reported	WMD 19.63 95% CI 11.69 to 27.56 P = 0.001	Effect size not calculated	botulinum B toxin
Systematic review	72 adults with cervical dystonia for at least 1 year and previously treated with botulinum A toxin, TWSTRS-total score >20 and TWSTRS-severity >10 Data from 1 RCT	Patient analogue pain assessment 0–4 weeks with botulinum B toxin (5000 U) with placebo Absolute results not reported	WMD 18.00 95% CI 5.69 to 30.31 P = 0.004	Effect size not calculated	botulinum B toxin