Included studies and participant characteristics.

DQ calculated as mean mental age/mean chronological age × 100.a Total number of children in study (n) and the number of children in the treatment (T) and control (C) groups.b IQ estimate based on our interpretation of participant characteristics.c LMIC status according to the World Bank.d This study contained three treatment groups and one control group (n = 10).e This study contained two treatment groups and one control group (n = 24).ASD, autism spectrum disorder; ID, intellectual disability; n/a, not available; SD, standard deviation.