Early detection and diagnosis of developinental disability has been practiced in many districts in Japan recently. In Matsue, Shimane prefecture, such a public enterprise was started on three years ago. Before then, medical diagnosis formed the nucleus on the health examination for infants. Introducing the developmental viewpoint, infants who undergoes the developmental examination increase in number and developmental disability is detected effectively.
But in diagnosing developmental disorder, we must consider their motive powers of development. The necesslty of this point of view is posed through one of those cases in this paper.