Cognitive-communicative development of identical triplets, one with unilateral cleft lip and palate.

Identical male triplets, one with a complete unilateral cleft, were studied developmentally from 16 to 25 months of age and tested with several cognitive-communicative developmental measures. Measures of hearing and motor and behavioral development also were obtained. The triplets did not differ from normative data or from each other on hearing, motor, behavioral, and for the most part, cognitive-mental measures. All of the children were within normal limits on receptive communication measures; however, all were delayed on expressive measures. The triplet with the cleft was more delayed than his brothers. Discussion centers on the interaction of variables that may account for this differential effect in expressive measures in relation to the structural anomaly.