Relationship between the home environment and sensorimotor development of Down syndrome and nonretarded infants.

Thirteen Down syndrome and 19 nonretarded infants participated in a prospective, longitudinal study designed to investigate the effect of the home environment on sensorimotor development as assessed by infant tests and direct observation of behavior. The present paper is concerned with the age span from 6.5 to 24 months. The two groups did not differ on measures of the social environment obtained at 6.5 months but differed on such measures at 17 months. At 6.5 months, the amount of tactile stimulation, encouragement of postural control, and level of social stimulation were all related to concurrent test performance in both groups; characteristics of the inanimate environment were of longer-term predictive significance among the Down syndrome babies. At 17 months, mothers' referential speech was related to the developmental pattern from 6.5 to 24 months for the Down syndrome children. The Down syndrome children tended to explore objects as a solitary activity, whereas exploration was done within the interactional situation by the nonretarded subjects. An attempt at multiple prediction demonstrated the usefulness of an interactional approach, showing the joint predictive value of language behavior and mothers' referential speech. Of special concern was how slowness of development among Down syndrome children may be a factor producing changes in maternal behavior.