Locomotor Learning in Infants at High Risk for Cerebral Palsy

Children's Hospital Los Angeles, University of Oklahoma, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

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).

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.

This study has three phases. The first phase of the study will be the observation of early spontaneous leg movements which will be measured monthly from 1-4 months of age. The prone locomotor intervention phase using the Self-Initiated Prone Progression Crawler (SIPPC) will occur from 5-9 months of post-term age, or end earlier if the child achieves the ability to crawl six feet. Treatment will occur at an intensity of 3 times per week for 15-30 minutes. Infants will use the SIPPC for the duration of each therapy session The upright locomotor intervention phase using DWS will occur from 9-18 months of age, or begin earlier if the child achieves the ability to crawl six feet before 9 months of age, and end earlier if the child achieves independent walking before 18 months of age. Treatment will occur at an intensity of 3 times per week for 30 minutes. Infants will receive dynamic weight support (DWS) for the duration of the 30-minute therapy session.

During the movement observation phase, infants will wear a wireless movement sensor at each ankle for two days. Research staff will show the caregivers how to place the sensors in the morning and charge them overnight. The training protocol for the prone training will consist of: 1) Warm-up. 2) Assisted movement of the arms and legs. 3) Calibration of the infant's arm and leg positions. 4) Self-initiated mobility for up to five minutes. For upright training, the environment will be arranged to encourage active motor exploration and variability in walking activities.The therapist will assist the child as needed to encourage upright locomotor activities, but only the minimum amount needed to perform the task. Weight assistance will be gradually reduced as postural control and coordination improve.

The Gross Motor Function Measure-66 (GMFM-66) is a Rasch-analyzed measure of gross motor function designed for children with cerebral palsy (CP). Computation of the GMFM-66 score involves statistical weighting of the raw item scores for difficulty. Scores range from 0 to 100 with higher scores indicating more functional ability.

The Movement Observation Coding System will use video coding to assess postural control, arm and leg movements, and goal directed movement.

Wearable sensor data will be analyzed to describe leg movements produced across in the natural environment.

Error during prone locomotor training will measured using the Self-Initiated Prone Progression Crawler (SIPPC).

Error during upright locomotor training will measured using the dynamic weight support (DWS) technology.

Movement index is the percent of time moving during each therapy session which will be recorded by sensors.

Movement variability during prone locomotor training will be measured using the Self-Initiated Prone Progression Crawler (SIPPC).

The cognition age equivalent obtained from the Bayley Scales of Infant and Toddler Development- Fourth Edition (BSID-IV). This value describes what age the child is currently similar to in their cognitive performance, and all values are reported in months of age. The range of values on the scale 0-42 months of age. A higher number value means a greater cognitive ability.

The Motivation to Move Scale is scored from video data of infant behavior during treatment sessions. Children are classified on a scale of 1 to 5 with higher scoring indicating increased motivation to move.

Inclusion Criteria: less than 6 weeks of age (corrected for prematurity, if applicable) have a history of an early brain injury associated with high risk for cerebral palsy including periventricular leukomalacia, hypoxic-ischemic encephalopathy, intraventricular hemorrhage, hydrocephalus, stroke, neonatal seizures, or intracranial cystic lesion family is able to commit to study visits Exclusion Criteria: * known genetic condition unrelated to cerebral palsy (CP) or congenital abnormalities Infants with fidgety movements on the General Movements Assessments (GMA) at 3 months of age or a score greater than -0.5sd below the mean on the Test of Infant Motor Performance at 4 months of age will not progress in the study because these infants are unlikely to have CP.