Kang 2011.
| Methods | Randomised double‐blind sham‐controlled cross‐over trial | |
| Participants | Country: Republic of Korea
10 right‐handed Korean participants (2 women) with post‐stroke aphasia due to single left hemispheric infarction, age 46 to 73 years (mean ± SE, 61.9 ± 2.7) with mean full‐time education time 0 to 16 (mean ± SE, 11.6 ± 1.5), mean time from stroke onset to study entry 52.4 ± 21.9 months (range 6.0 to 180.6 months) Inclusion criteria: not clearly stated Exclusion criteria: multiple brain lesions, unstable medical or neurological conditions, metallic foreign body within the brain, pacemaker or artificial cochlear implant, severe depression, history of seizures and inability to perform protocol‐related behavioural tasks |
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| Interventions | Every participant underwent both of the following treatment conditions, each over right Broca's homologue area: ‐ word retrieval training + 5 days C‐tDCS (2 mA for 20 minutes), at least 7 days' rest period, word retrieval training + 5 days S‐tDCS (20 minutes) ‐ word retrieval training + 5 days S‐tDCS (20 minutes), at least 7 days' rest period, word retrieval training + 5 days C‐tDCS (2 mA for 20 minutes) |
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| Outcomes | Outcomes were reported at baseline and at the end of each treatment phase: ‐ number of correct responses (0 to 60 with 60 reflecting highest correctness) and ‐ reaction time of an adapted, standardized, validated Korean version of the BNT (0 to infinity with a lower value indicating better performance) |
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| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Not stated by the study authors |
| Allocation concealment (selection bias) | Unclear risk | Not stated by the study authors |
| Blinding of participants and personnel (performance bias) Objective outcomes | Low risk | Objective outcome measures: 1) personnel: "Word‐retrieval training was provided by a speech and language pathologist who was unaware of the type of stimulation administered (C‐tDCS or sham)"; 2) participants: "This sham procedure does not elicit patient's perceptions and was performed out of the patients' view" |
| Blinding of outcome assessment (detection bias) Objective outcomes | Low risk | Objective outcome measures: "A single rater, unaware of stimulation type, administered the BNT" |
| Incomplete outcome data (attrition bias) Objective outcomes | Low risk | Objective outcome measures: all participants apparently completed the study. No treatment withdrawals, no trial group changes and no major adverse events stated |
| Selective reporting (reporting bias) | Unclear risk | All outcomes listed in the 'Methods' section reported, no protocol could be identified |
| Other bias | Unclear risk | No other bias identified |