Transcranial direct current stimulation for post-stroke dysphagia: a meta-analysis

Table 4 Risk of bias for included studies (RoB tool results)

Authors	Random sequence (selection bias)^a	Allocation concealment (selection bias)^b	Blinding of participants and personnel (performance bias)	Blinding of outcome assessment (detection bias)	Incomplete outcome data (attrition bias)^c	Selective reporting (reporting bias)^d	Other bias	Overall
Ahn et al. [35] (2017)	Low	Low	Low	Low	High	Low	Low	High
Farpour et al. [41] (2023)	Low	Low	Low	Low	Low	Low	Low	Low
Kumar et al. [32] (2011)	Low	Low	Low	Low	Low	Low	Low	Low
Mao et al. [36] (2021)	Low	Low	Moderate	Low	Low	Low	Low	Low
Pingue et al. [33] (2018)	Low	Low	Low	High	Low	Low	Low	High
Sawan et al. [34] (2020)	Low	Moderate	Moderate	Low	High	Low	Low	High
Shigematsu et al. [37] (2013)	Low	Low	Moderate	Low	Low	Low	Low	Low
Suntrup-Krueger et al. [38] (2018)	Low	Low	Low	Low	Low	Low	Low	Low
Wang et al. [39] (2020)	Low	Low	Moderate	Low	Low	Low	Low	Low
Wang et al. [42] (2023)	Low	Low	Moderate	Low	Low	Low	Low	Low
Yang et al. [40] (2012)	Low	Moderate	Moderate	Low	Low	Low	Low	Moderate

^aRisk of bias from confounding was considered critical when confounding was not inherently controlled for (i.e. no or limited adjustment). ^bSelection bias was critical when selection into the study was very strongly related to intervention and outcome. This occurred when the study included men with diagnoses other than erectile dysfunction. ^cRisk of bias due to missing data was considered moderate when there appeared to be a substantial amount of missing data. In these cases, the proportions of and reasons for missing data might differ across interventions groups. Of note, the majority of studies did not report on missing data. The risk of bias for these were classified as low, but could also be considered “unknown”. ^dThe studies with a moderate risk for selective outcome reporting were those that did not provided a pre-registered protocol

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