Table 1.

Studies included in the review, methodology assessment according to the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM)^a.

Study	Research design	Level of evidenceb	AACPDM conduct questionsc							Quality scores	Quality summary
			1d	2d	3	4d	5	6d	7d
Ulrich et al. (32)	RCT	II	Yes	No	Yes	No	Yes	No	Yes	4	Moderate
Ulrich et al. (33)	RT	II	Yes	Yes	Yes	No	Yes	Yes	Yes	6	Strong
Angulo-Barrosso et al. (34)	RCT	II	Yes	Yes	Yes	No	Yes	Yes	Yes	6	Strong
Campbell et al. (30)	CCT	II	Yes	No	No	Yes	No	Yes	Yes	4	Moderate
Lee and Samson (35)	Cohort study	V	Yes	No	Yes	No	No	Yes	No	3	Weak
Schlittler et al. (36)	CCT	II	Yes	No	No	No	Yes	No	No	2	Weak
Kolobe and Fagg (31)	Cohort study	V	Yes	No	Yes	Yes	Yes	No	No	4	Moderate
Wentz (37)	CCT	II	Yes	Yes	Yes	No	Yes	Yes	No	5	Moderate
Cameron et al. (38)	RCT	II	Yes	No	No	Yes	Yes	Yes	Yes	5	Strong
Ustad et al. (39)	Cohort study	V	Yes	No	No	Yes	No	No	No	2	Weak

The order of articles presentation was made according to the type of training.

^aCriteria for methodological quality assessment according to the AACPDM (revision 1.2) 28 with adjustments for the current study in italics.

^bLevel of evidence from Sackett et al. (21).

^cAACPDM conduct questions:

1: Were inclusion and exclusion criteria of the study population well-described and followed? Both inclusion and exclusion criteria need to be met to score “yes”.

2: Were the intervention and comparison condition well-described and was there adherence to the intervention assignment? Both parts of the question need to be met to score “yes.” Adherence to intervention implies that adherence is assessed in a systematic way (questionnaire, video) and that >65% of planned intervention was achieved. The cut off of 65% adherence was an arbitrary one based on common sense; it meant that about two-thirds of the intervention had been achieved.

3: Were the measures used clearly described, valid and reliable for measuring the outcomes of interest?

4: Was the outcome assessor unaware of the intervention status of the participants (i.e., was it explicitly described that the assessors were masked)?

5: Did the authors conduct and report appropriate statistical evaluation: that is, did they perform proper statistics and did they include a power calculation (the latter did not need to result in the demonstration of group sizes allowing for adequate power)? Both parts of the question need to be met to score “yes”.

6: Were dropout/loss to follow-up after start of the intervention reported and <20%? For two-group designs, was dropout balanced? Note that dropouts due to death are excluded from the dropout calculation.

7: Considering the potential within the study design, were appropriate methods for controlling confounding variables and limiting potential biases used? Studies with groups with n <10 at the end of the intervention—either because they started with small groups or attrition resulted in groups with fewer than 10 participants—are assigned “no,” as the small number precludes multivariable statistics to control for confounders. Methodological quality is judged—according to the AACPDM criteria—as strong (‘yes’ score on ≥six questions), moderate (score 4 or 5), or weak (score ≤3).

^dCriteria that address the risk of bias within studies. RCT, randomized controlled trial.