Characteristics of motor development of autism spectrum disorder children until unassisted walking stage

Abstract

There have been few reports on the aspects of the motor function development of autism spectrum disorder (ASD) infants in infancy. In the present study, we investigated the motor development characteristics of ASD infants before the stage at which they acquired the ability to walk unassisted. The subjects were 150 ASD infants (112 males and 38 females), who did not have any clear underlying disease and based on their charts we retrospectively selected motor function acquisition ages until acquiring the ability to walk unassisted. We assessed six parameters: head control, roll over, sitting, crawling, standing up, and walking unassisted and calculated the numbers of infants classified according to whether within the normal range and early or late outside the normal range, by using Japanese edition Denver style development screening test. We also investigated the sequence of motor function acquisition. The mean ages of the ASD infants when they acquired the motor functions were within their normal ranges, but the standard deviations of the ages of acquisition successively widened. Although 122 infants (81%) were within the normal range for the turnover, 83 infants (55%) were within the normal range for walking unassisted. The sequence of motor function acquisition was normal in 54 infants (36%) and irregular in 96 infants (64%), and a tendency was also seen for irregularities in the sequence of acquisition to become greater. Motor development in typically developing children progresses stepwise. However, when motor development delay or a course of motor development outside the normal range in terms of age in months at the time of acquisition is observed despite the absence of any clear underlying disease, it is necessary to bear the possibility of ASD in mind and intervene early, while monitoring the course of the child's interpersonal relations, social skills, behavior, and motor development.