Sakrajai 2014

Methods	Parallel RCT
Participants	Country of study: Thailand Setting: laboratory Condition: myofascial pain syndrome (affecting shoulder) Prior management details: stable analgesic use for 3 months preceding study n = 31 Age mean (SD): active group 49.94 (8.25) years, sham group 45.93 (10.24) years Duration of symptoms, mean(SD) active group 5.91 (2.55) months, sham group 45.93 (10.24) Gender distribution: 22 F, 9 M
Interventions	Stimulation type: tDCS Stimulation parameters: intensity 1 mA, 35 cm2 electrodes, duration 20 min Stimulation location: anode M1 contralateral to most painful side, cathode supraorbital area contralateral to anode Number of treatments: x 1 daily for 5 days Control type: sham tDCS
Outcomes	Primary: pain VAS, anchors 0 = no pain, 10 = the most possible pain When taken: post‐treatment, average of daily score in week 1 postintervention, week 2, 3, 4 postintervention. Only responder analysis presented Secondary: QoL WHO‐QoL, data not reported AEs
Notes	COI: "M.P.J. is a consultant to Noninvasive Brain Stimulation Research Group of Thailand. The remaining authors declare no conflict of interest." Sources of support: "Supported in part by Grant Number R21 HD058049 from the National Institutes of Health, National Institute of Child Health and Human Development, Rockville, MD; and National Center for Medical Rehabilitation Research, Rockville, MD."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: method of sequence generation not described
Allocation concealment (selection bias)	Unclear risk	Comment: allocation concealment procedures not described
Adequate blinding of participants?	Low risk	Comment: “The tDCS device was designed to allow for masked (sham) stimulation. Specifically, the control switch was in front of the instrument, which was covered by an opaque adhesive during stimulation. The power indicator was on the front of the machine, which lit up during the time of stimulation both in active and sham stimulations.”
Adequate blinding of assessors?	Unclear risk	Comment: blinding of assessors not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: only 1 dropout
Selective reporting (reporting bias)	Low risk	Comment: no numeric reporting of pain score or QoL point estimates in the paper. All data provided by study authors upon request
Study Size	High risk	Comment: n = 31
Study duration	Unclear risk	Comment: 4‐week follow‐up postintervention
Other bias	Low risk	Comment: no other bias detected