Table 3.

Criteria for risk of bias assessment

	Question	Criteria for “Yes”	Judgment
A	1. Was the method of randomization adequate?	A random (unpredictable) assignment sequence. Examples of adequate methods are coin toss, rolling a dice, drawing of ballots with the study group labels from a dark bag, computer-generated random sequence, pre-ordered sealed envelops, sequentially ordered vials Examples of inadequate methods are alternation, birth date, social insurance/security number, and hospital registration number	Yes/No/Unsure
B	2. Was the treatment allocation concealed?	Assignments are generated by an independent person not responsible for determining the eligibility of the patients. This person has no information about the persons included in the trial and has no influence on the assignment sequence or on the eligibility decision of the patient	Yes/No/Unsure
C	3. Was the patient blinded to the intervention?	The index and control groups are indistinguishable for the patients	Yes/No/Unsure
	4. Was the care provider blinded to the intervention?	The index and control groups are indistinguishable for the care providers	Yes/No/Unsure
	5. Was the outcome assessor blinded to the intervention?	• For patient-reported outcomes with adequately blinded patients • For outcome criteria that supposes a contact between participants and outcome assessors: the blinding procedure is adequate if patients are blinded, and the treatment or adverse effects of the treatment cannot be noticed during examination • For outcome criteria that do not suppose a contact with participants: the blinding procedure is adequate if the treatment or adverse effects of the treatment cannot be noticed during the assessment • For outcome criteria that are clinical or therapeutic events that will be determined by the interaction between patients and care providers, in which the care provider is the outcome assessor: the report needs to be free of selective outcome reporting	Yes/No/Unsure
D	6. Was the drop-out rate described and acceptable?	The number of participants who were included in the study but did not complete the observation period or were not included in the analysis are described and reasons are given and are <20 % for short-term and <30 % for long-term follow-up	Yes/No/Unsure
	7. Were all randomized participants analyzed in the group to which they were allocated?	All randomized patients are reported/analyzed in the group they were allocated to by randomization for the most important moments of effect measurement (minus missing values) irrespective of non-compliance and co-interventions	Yes/No/Unsure
E	8. Are reports of the study free of suggestion of selective outcome reporting?		Yes/No/Unsure
F	9. Were the groups similar at baseline regarding the most important prognostic indicators?	The groups have to be similar at baseline regarding demographic factors, duration and severity of complaints, percentage of patients with neurological symptoms, and value of main outcome measure(s)	Yes/No/Unsure
	10. Were co-interventions avoided or similar?	There were no co-interventions or they were similar between the index and control groups	Yes/No/Unsure
	11. Was the compliance acceptable in all groups?	The compliance with the interventions is acceptable, based on the reported intensity, duration, number and frequency of sessions for both the index intervention and control intervention(s). For single-session interventions (for ex: surgery), this item is irrelevant	Yes/No/Unsure
	12. Was the timing of the outcome assessment similar in all groups?	Timing of outcome assessment was identical for all intervention groups and for all important outcome assessments	Yes/No/Unsure