Early spontaneous leg movements will be measured monthly from 1-4 months of age. Infants who remain at high risk for CP by month 4 as measured by the General Movements Assessment and the Test of Infant Motor Performance (TIMP) at 4 months of age will continue to locomotor training phases. Prone locomotor training using the Self-Initiated Prone Progression Crawler (SIPPC) will be delivered from 5-9 months of age. Upright locomotor training with dynamic weight support (DWS) will be delivered from 9-18 months of age. Repeated assessments of locomotor skill, movement quality, training characteristics, and variables that may mediate locomotor learning will be collected at time points from 1 month to 18 months of post-term age.~Investigators will examine the relationships between motor error and locomotor skill acquisition over time, anticipating that experiencing and correcting movement errors is critical to skill acquisition in infants at risk for CP; the contribution of other training characteristics (movement time, movement variability, and postural control) to locomotor learning; and how learning is mediated by neurobehavioral factors outside of training. Investigators will develop comprehensive models of training predictors and mediators for prone and upright locomotor learning.
The objective of this project is to characterize the evolution of locomotor learning over the first 18 months of life in infants at high risk for cerebral palsy (CP). To characterize how locomotor skill is learned (or not learned) during this critical period, the investigators will combine established protocols using robust, unbiased robotic and sensor technology to longitudinally study infant movement across three consecutive stages during the development of impaired human motor control - early spontaneous movement, prone locomotion (crawling), and upright locomotion (walking).