Mendonca 2016

Methods	Parallel RCT
Participants	Country of study: Brazil Setting: laboratory Condition: fibromyalgia Prior management details: excluded if undergoing physical treatment or were on stable pain control medication for "less than 2 months" n = 45 (of which 30 relevant to this review) Age, mean (SD): active group 44.5 (14) years, sham group 48 (11.8) years Duration of symptoms, mean (SD): active group 140.6 (72.2) months, sham group 149.3 (111.1) Gender distribution: 29 F, 1 M
Interventions	Stimulation type: tDCS Stimulation parameters: intensity 2 mA, 35 cm2 electrodes, duration 20 min Stimulation location: anode L M1, cathode right supraorbital area Number of treatments: x 1 daIly for 5 days Control type: sham tDCS
Outcomes	Primary: pain VAS, anchors 0 = no pain, 10 = worst pain imaginable When taken: postintervention, 1 month postintervention, 2 months postintervention Secondary: QoL SF‐36 AEs
Notes	Study authors declared that there were no COI
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: “Randomization was performed by a blinded therapist using sealed envelopes for each individual.” Comment: no description of the actual allocation sequence generation
Allocation concealment (selection bias)	Low risk	Quote: “Randomization was performed by a blinded therapist using sealed envelopes for each individual.” Comment: likely to be a concealed process
Adequate blinding of participants?	Unclear risk	Quote: “Participants were blinded to the intervention groups, as were the therapists who performed the evaluation.” Comment: evidence that blinding can be inadequate at intensity of 2 mA. No formal assessment of blinding success
Adequate blinding of assessors?	Unclear risk	Quote: “Participants were blinded to the intervention groups, as were the therapists who performed the evaluation.” Comment: Evidence that assessor blinding can be inadequate at intensity of 2 mA. No formal assessment of blinding success
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: ITT analysis using LOCF. Low for postintervention (< 10%) and high for 2/12 follow‐up
Selective reporting (reporting bias)	Low risk	Comment: adequate reporting of core outcomes
Study Size	High risk	n = 45 in 3 groups of which n = 30 relevant to this review
Study duration	Low risk	2‐month postintervention follow‐up
Other bias	Low risk	Comment: no other bias detected