Development of adaptive motor behaviour in typically developing infants

Aim: During motor development, infants learn to select adaptive motor strategies out of their motor repertoire. The aim of this study is twofold: first, to investigate whether the presence of adaptive motor behaviour can be observed reliably, and second, to explore the ages at which clinically observable transition to adaptive motility emerges for four specific motor functions: abdominal progression, sitting motility, reaching and grasping. Methods: The reliability part of the study included 38 assessments of term and preterm infants in the age range of 4-18 months. The longitudinal prospective study included 30 term born typically developing infants with nine assessments between 3 and 18 months. On the basis of standardized video-recordings of spontaneous motor behaviour, the presence of adaptive motor strategies was scored. Results: Intra- and interobserver reliability were good. Clinically observable transitions to adaptive selection started to emerge from 6 months onwards and peaked between 8 and 15 months. Transitions developed gradually and occurred at specific ages for different motor functions. Conclusion: Transition to adaptive motor behaviour can be observed reliably. Adaptive motor behaviour develops gradually from 6 months onwards at function-specific ages. Comparison of our results to literature showed that changes measured by neurophysiologic methods precede clinically observed transitions.