TABLE 2.

Characteristics of the studies included in the review.

Study	Study design	VFI protocol	Setting	Sample size (dyads)	Sessions number	Sessions frequency	Children age	Clinical category
Mahoney and Powell (1988)	Trial	TRIP	Home	41	N.A.	>Weekly	2–32 months	ND
Seifer et al. (1991)	Trial	N.A.	Hospital	40	6	Weekly	8.5 months	ND
Kim and Mahoney (2005)	Trial	RFI	Home	18	2	Weekly	3–8 years	ND
Phaneuf and McIntyre (2007)	Case study	IVF	Home	4	1–3	>Weekly	2–4 years	ND
Phaneuf and McIntyre (2011)	Case study	N.A.	Home	8	1–3	N.A.	2–4 years	ND
James et al. (2013)	Case study	VIG	Home	3	3	>Weekly	9–36 months	Hearing impairments* and ND
Glanemann et al. (2013)	Trial	MPP	Hospital	29	8	Weekly	3–6 months	Hearing impairments* and ND
Lam-Cassettari et al. (2015)	Trial	N.A.	Hospital	14	3	N.A.	2.5 years	Hearing impairments* and ND
Sealy and Glovinsky (2016)	Trial	DIR/FT	Hospital	40	12	N.A.	2–6 years	ND
Platje et al. (2018)	Trial	VIPP-V	Home	40	7	>Weekly	1–5 years	Visual or visual-and-intellectual disability

N.A., not available; ND, neurodevelopmental disability; TRIP, Transactional Intervention Program; RFI, Relationship-Focused Intervention; IVF, Individualized Video Feedback; VIG, Video Intervention Guidance; DIR/FT, Developmental Individual-difference, Relationship-based/Floortime Intervention; VIPP-V, Video feedback Intervention to promote Positive Parenting in parents of children with visual or visual-and-intellectual disabilities; MPP, Muenster Parental Program; *, onset of hearing impairments is prelingual.