Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Neurological disability
RCT	40 treatment-naive people with symptoms of idiopathic writer's cramp for at least 1 year	Mean improvement in symptom severity scale –3.60 with botulinum A –1.16 with placebo Assessed using symptom severity scale, reduction in score indicates improvement	P = 0.02	Effect size not calculated	botulinum A toxin
RCT	40 treatment-naive people with symptoms of idiopathic writer's cramp for at least 1 year	Mean improvement in writer's cramp scale –2.30 with botulinum A –0.79 with placebo	P <0.01	Effect size not calculated	botulinum A toxin
RCT	40 treatment-naive people with symptoms of idiopathic writer's cramp for at least 1 year	Mean improvement in handwriting 1.85 with botulinum A 0.53 with placebo Assessed using a visual analogue scale from 0 cm to 10 cm	P = 0.01	Effect size not calculated	botulinum A toxin
RCT	40 treatment-naive people with symptoms of idiopathic writer's cramp for at least 1 year	Mean change in writing speed 1.41 with botulinum A 0.27 with placebo Mean change in writing speed = number of lines written in 2 minutes	P = 0.04	Effect size not calculated	botulinum A toxin
RCT	40 treatment-naive people with symptoms of idiopathic writer's cramp for at least 1 year	Mean improvement in functional status +0.65 with botulinum A –1.42 with placebo	P = 0.10		Not significant