Fridriksson 2018.

Methods	Randomised sham‐controlled double‐blind trial
Participants	Country: USA 74 right‐handed people between 25 and 80 years of age, with aphasia due to left‐hemispheric first‐time ever stroke, more than 6 months post stroke, who are native English speakers Inclusion criteria: willing and able to give informed consent, willing and able to comply with study requirements, at least 65% accuracy on naming task during screening Exclusion criteria: previous brain surgery, seizures during last 12 months, sensitive scalp (self‐report), being able to name more than an average of 140 out of 175 items during the pre‐treatment PNT, inability to overtly name at least an average of 5 out of 80 items during the pre‐treatment fMRI sessions
Interventions	2 arms: ‐ A‐tDCS (1 mA) for 20 minutes over the left scalp over the individually most active cortex region identified by naming tasks fMRI during 45 minutes of computerised naming treatment ‐ S‐tDCS for 20 minutes over the left scalp over the individually most active cortex region identified by naming tasks fMRI during 45 minutes of computerised naming treatment
Outcomes	Outcomes were recorded at baseline and at 1 week after the end of intervention period: Primary outcomes: ‐ change in correctly named objects of the PNT Secondary outcomes: ‐ adverse events during intervention period
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The Biostatistics Core at the Data Coordination Unit (located at Medical University of South Carolina) programmed the randomization algorithm, which used the minimal sufficient balancing method to prevent imbalances in site, baseline age, aphasia type, and aphasia severity."
Allocation concealment (selection bias)	Low risk	Quote: "Study participants and all members of the study team (the speech language pathologists [SLPs] who administered clinical testing and treatment, study coordinators, and principal and co‐investigators) were blinded to the intervention assignment."
Blinding of participants and personnel (performance bias) Objective outcomes	Low risk	Quote: "To blind patients as to whether they were receiving active or sham tDCS, the same scalp sensation was induced during the start of the S‐tDCS sessions when the tDCS stimulation was applied to the scalp for 30 seconds but then the current was gradually decreased over 15 seconds as the current was shunted to a load resistor. In‐house hardware was used to mask treatment type (A‐tDCS vs S‐tDCS) for both patients as well as the SLPs. The described randomization scheme directed an independent technician to set the position of an internal switch on the sham controller. Neither the patient nor SLP was aware of the position and the SLP did not know which switch position (X or Y) was the sham position. Treatment type was encoded in the software so the SLP only needed to enter a patient and session number to start stimulation without knowing whether those specific numbers were assigned toA‐tDCS or S‐tDCS.Following each individual’s treatment, a technician validated whether the tDCS device was delivering anodal or sham stimulation."
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Please see "Allocation concealment".
Incomplete outcome data (attrition bias) Objective outcomes	Low risk	The authors performed an intention‐to‐treat analysis. 33 out of 34 patients (97%) in the experimental group and 39 out of 40 patients (98%) in the control group received the assigned intervention. In the experimental group there were 3 dropouts (9%) until follow‐up (reasons not stated), whereas in the control group there were 2 dropouts (8%) with 1 patient's reasons being put down to adverse events.
Selective reporting (reporting bias)	Unclear risk	Results of naming error analysis presented in the protocol (supplementary file) not presented
Other bias	Low risk	No other bias identified