Effects of dose frequency of early communication intervention in young children with and without Down syndrome

Abstract

Children with intellectual disability were randomly assigned to receive Milieu Communication Teaching (MCT) at one 1-hr session per week (low dose frequency, LDF) or five 1-hr sessions per week (high dose frequency, HDF) over 9 months ( Fey, Yoder, Warren, & Bredin-Oja, 2013 . Non-Down syndrome (NDS) and Down syndrome (DS) subgroups were matched on intelligence, mental age, and chronological age. The NDS group had significantly more growth in spoken vocabulary than the DS group. In the DS subgroup, the HDF group had more spoken vocabulary growth than the LDF group when IQ was controlled. In both etiological subgroups, the HDF group yielded greater vocabulary production outcomes than the LDF group for children who played functionally with a range of objects.

Figure 1

Average growth in the number of words spoken as a function of diagnosis controlling for Bayley III Cognitive Composite standard score. Y-axis reflects log10 transformed values (Log 10 (x+1)) for the number of words children were reported to say on the MacArthur-Bates Communicative Development Inventory. X-axis denotes time in study (in months) centered at post-treatment (completion of the 9-month treatment protocol). NDS = non-Down syndrome (mixed-etiology ID) subgroup, DS= Down syndrome subgroup.

Figure 2

Effects of dose frequency (DF) on spoken vocabulary growth controlling for Bayley III Cognitive Composite standard score in children with Down syndrome (DS). Y-axis reflects log10 transformed values (Log 10 (x+1)) for the number of words children were reported to say on the MacArthur-Bates Communicative Development Inventory. X-axis denotes time in study (in months) centered at post-treatment (completion of the 9-month treatment protocol). LDF = low dose frequency, HDF = high dose frequency. Note: Controlling for Time 1 number of words said did not affect the interpretation of the dose frequency effects.