Sensorimotor and action development in autistic children from infancy to early childhood.

Home movies of eight normal children and eight children later diagnosed as autistic were analysed according to development in sensorimotor and action competencies. The age range covered was from 4 to 42 months of age. From the beginning of the second year of life, the timing and sequence of developmental gains in normal and autistic children show striking differences. One year later the development of the autistic children seems to be not only delayed, but qualitatively different with respect to the more challenging kinds of action outcomes. This is particularly noticeable for action outcomes involving mental representations of the intended outcome.