Table 3.

Participant characteristics.

Study	No. of participants	Geographical location	Demographics: parent	Demographics: child
Hamad et al [49]	51	“Geographically disparate” in the United States	Gender: male n=4, female n=47 Age: not specified Education level: high school n=6, associate degrees n=0, bachelor degrees n=20, master degrees n=12, other n=3 Note: subgroup demographic breakdown not provided	Gender: not specified Age: not specified
Heitzman-Powell et al [50]	7	Remote areas in the United States	Gender: not specified Age: mean age 37.3 (range=32-47) Education level: ranged from graduate degree to high school diploma. Breakdown not specified.	Gender: not specified Age: not specified
Ingersoll and Berger [43] Ingersoll et al [44] Pickard et al [45]	27	70% (19/27) of participants resided in “rural or medically underserved areas”	Gender: male n=1, female n=26 Age: not specified Education: college degree or higher=16, education levels of remaining participants not specified	Gender: male n=19, female n=8 Age: mean chronological age 3 years, 6 months.
St. Peter et al [46]	32	Rural Appalachian counties in West Virginia, Kentucky, Maryland, Virginia, or Pennsylvania, United States	Gender: male n=11, female n=21 Age: mean age of parents=35.87 years (range, 24-69) Education level: 54.15% had received a college degree. Remaining participant education levels not specified.	Not specified
Vismara et al [48]	8	“Very little access to early intervention services” in California, North Carolina, Arkansas, Texas, and Pennsylvania, United States.	Gender: male n=1, female n=7 Age: not specified Education: not specified	Gender: male n=7, female n=1 Age: mean chronological age 2 years, 4 months (standard deviation=7.6 months, range 16-38 months)
Vismara et al [12]	8	“Minimally available intervention services in their community” in the United States and Canada	Gender: male n=1, female n=7 Age: not specified Education level: college n=4, postcollege n=4	Gender: not specified Age: 1 year n=4, 2 years n=2, 3 years n=1
Wacker et al [47]	17	Regional Iowa, United States	Gender: male n=2, female n=16 Age: mean age 33 years Education level: “most” had some level of postsecondary education. Breakdown not specified.	Gender: male n=16, female n=1 Age: 2 years n=3, 3 years n=4, 4 years n=3, 5 years n=5, 6 years n=2 (range 29-80 months)