Table 2.

Risk of bias assessments for individual randomized studies according to standardized criteria (Risk of Bias tool [5, 12]). A minus sign (-) indicates a high risk of bias assessment, and a plus sign (+) indicates a low risk of bias assessment for the randomized studies. A question mark (?) indicates some concerns of bias due to insufficient documentation or information. No symbol indicates the type of bias could not be assessed

Randomized studies (RoB tool assessment criteria)	Holmes et al., 2007 [7]	Rowe et al., 2010 [8]	Rowe et al., 2009 [9]
Random sequence generation	-	-b	-c
Allocation concealment	-	-	-
Blinding of participants / personnel	-	-	-
Blinding of outcome assessment	-	-	-
Incomplete outcome data	-	-	+
Selective reporting	+	+	+
Other bias	?a
Comments	a staff showed “resistance” to the intervention and altering methods of care	b 8 participants were exempted from randomization according to preference or previous study participation	c 8 participants were exempted from randomization according to preference or previous study participation