Mental age and cognitive stage in young handicapped and at-risk children

This research addressed the question of whether stage-related patterns of early cognitive development, reported for normally developing children in the first two and a half years of life, may also characterize the development of at-risk and handicapped children when mental age rather than chronological age is used to organize the data. Performance on a psychometric infant test and two neo-Piagetian-based stage measures was assessed for 95 at-risk and handicapped children. Mental age predicted cognitive level of performance for levels 1 to 3, representing the first year and a half of development, but did not predict the highest level, symbolic functioning. In addition, transition points between levels were observed at mental ages similar to the chronological ages when these transitions have been reported for normally developing infants, for all but the last level. The significance of the correspondence between the psychometric measure and the stage measures is discussed and several alternatives for the breakdown at the highest level are considered.