Participants
Twenty-six children participated in the study with 13 children each in the DS (chronological age = 31.55 ± 4.14 months; mental age = 14.75 ± 1.84 months) and TD group (chronological age = 17.31 ± 1.64 months; mental age = 17.39 ± 1.96 months; Table 1). Parents of children in the DS group submitted a medical record confirming the genetic diagnosis of Trisomy 21. Parents of TD infants completed a brief screening to confirm absence of any birth/family/developmental history of delays. Additionally, all parents confirmed the absence of any significant physical/visual/hearing impairments which would impair child’s participation in the study. Participants in the DS group were recruited from local organizations, centers, and schools. TD infants were recruited through birth records obtained from the state and through word of mouth. The group demographics including the age, sex, ethnicity, and parents’ age and education are provided in Table 1. Both groups were similar in terms of mental age, sex, ethnicity, and parents’ age, but differed in terms of parents’ education (Table 1). The parents in the DS group had fewer years of education compared to the parents in the TD group (p < 0.05, Table 1). All parents signed the consent form approved by the university’s Review Board before participating in the study.