Shah‐Basak 2015.
| Methods | Randomised sham‐controlled cross‐over trial | |
| Participants | Country: USA Experiment 1: 12 participants (10 men, 2 women); mean age (SD): 64 (9) years; time since stroke (SD): 31 (30) months; educational level not described; mean WAB‐AQ (SD): 53 (24) Experiment 2: 7 participants who responded with improved naming ability on experiment 1 were enrolled in a randomised sham‐controlled cross‐over trial, 2 participants dropped out during this phase Inclusion criteria of experiment 1: single left‐hemispheric chronic stroke (> 6 months post stroke), mild‐to‐severe non‐fluent aphasia, premorbidly right‐handed, no history of neurological, psychiatric or unstable medical conditions Exclusion criteria of experiment 1: contraindications to either MRI or tDCS Inclusion criteria of experiment 2: positive response in naming ability in experiment 1 with at least 1 active electrode arrangement |
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| Interventions | Each participant, during constraint‐induced language therapy, once underwent on non‐consecutive days all of the following conditions with a mean (SD) intersession interval of 7 (6) days between each condition in experiment 1 in random order: ‐ 1: A‐tDCS over the left frontal area (F3) and the reference electrode over the contralateral mastoid (2 mA for 20 minutes once) ‐ 2: C‐tDCS over the left frontal area (F3) and the reference electrode over the contralateral mastoid (2 mA for 20 minutes once) ‐ 3: A‐tDCS over the right frontal area (F4) and the reference electrode over the contralateral mastoid (2 mA for 20 minutes once) ‐ 4: C‐tDCS over the left frontal area (F4) and the reference electrode over the contralateral mastoid (2 mA for 20 minutes once) ‐ 5: S‐tDCS over the left frontal area (F3) and the reference electrode over the contralateral mastoid (2 mA for 1 minute once) ‐ 6: S‐tDCS over the right frontal area (F4) and the reference electrode over the contralateral mastoid (2 mA for 1 minute once) In experiment 2 each participant underwent the following interventions in random order: ‐ 1 of the active setups described above (1 to 4) (2 mA for 20 minutes, 5 times per week for 2 weeks) and ‐ 1 of the sham setups described above (5 or 6) (2 mA for 1 minute, 5 times per week for 2 weeks) |
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| Outcomes | Outcomes were recorded at baseline, at the end of intervention phase and at 2 and 8 weeks after the end of intervention phase: ‐ WAB ‐ WAB‐AQ |
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| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "Each of the six subjects who entered Phase 2 was randomized to receive either real‐tDCS treatment (n = 3), or sham stimulation followed by real‐tDCS (n = 3)." |
| Allocation concealment (selection bias) | Unclear risk | Not described by the study authors |
| Blinding of participants and personnel (performance bias) Objective outcomes | Low risk | Quote: "The order of five conditions was counterbalanced across subjects, who were blinded to real or sham‐tDCS [...] The person administering tDCS was not blinded to tDCS conditions." |
| Blinding of outcome assessment (detection bias) Objective outcomes | Low risk | Quote: "Responses were recorded digitally and later scored offline by the investigator who was blinded to the montage." |
| Incomplete outcome data (attrition bias) Objective outcomes | Unclear risk | Objective outcomes: there were 2 dropouts out of 7 participants (29%) during experiment 2. No treatment withdrawals, no trial group changes and no major adverse events stated. 1 non‐responder was excluded from analysis |
| Selective reporting (reporting bias) | Unclear risk | All outcomes listed in the 'Methods' section reported, no published protocol could be identified |
| Other bias | Low risk | No other bias identified |