A New Study from USC finds Potential Developmental Markers of Infant Neuromotor Control

The Question

A study conducted by the University of Michigan found that infants with Down syndrome produced more low intensity activity than infants with typical development, and that infants who kicked less or kicked more slowly took a longer time to learn to stand [1]. This left researchers wondering how early motor activity influences the development of infant neuromotor control. Can we quantify instantaneous infant leg movement and characterize the kinematics to determine if a baby at risk of developmental delay is on a trajectory toward a later diagnosis of delay? Dr. Beth Smith, the Director of the Infant Neuromotor Control Lab at the University of Southern California, set out to answer this question.

The Participants Suit Up

Data was collected from 31 babies – 11 of which exhibited typical development and 20 of which were determined to be at risk of developmental delay. The Children’s Hospital of Los Angeles High Risk Follow-Up Clinic was one of the several places where qualified participants were found. After recruitment, the babies were scored on the Alberta Infant Motor Scale to determine their motor development status and the researchers measured their weight, length, and head circumference. At this point in the visit (always held in the morning), the researcher placed the Opal wearable sensors on the baby’s ankles to track their movement. The Opals were attached with custom-made leg warmers, photographed below.

Custom-made leg warmers by Stephanie Alves, Founder/Designer of ABL Denim.

The Results

The baby’s caregiver was told to go about their usual business for the day, but to keep a detailed activity log and capture the type and duration of different positions and activities. Once the data was collected and analyzed, they discovered that the at-risk infants demonstrated smaller Sample Entropy values in comparison with the typical development group. What does a small Sample Entropy value look like at home?

What Does it Look Like at Home?

Lower values of Sample Entropy can be interpreted as a baby with more similarity in movement patterns across time. In other words, they exhibit more repetitive and less exploratory behavior. Similar behavior has been seen in pre-term babies and infants with cerebral palsy or development delay. The results from Dr. Smith’s study support the theory that movement is necessary for exploration and marks the emergence of a new functional skill [2].

A Possible Solution

How can we help a baby at risk of developmental delay? Treadmill training has been used as error-based learning for teaching toddlers with cerebral palsy to walk. There is a strong case for increasing an infant’s activity level and the variability of activities early on to encourage more typical development rather than waiting until the disparity is obvious.

APDM Wearable Technologies – More Than Just Activity Monitoring

APDM Wearable Technologies offers sensor-based solutions for quantifying human movement. Independently validated and trusted by thousands of researchers worldwide, APDM’s digital health solutions are used to analyze full-body kinematics, gait, and balance. Applications range from neurological assessments, rehabilitation research, clinical trials, fall-risk, continuous monitoring, and more. To learn more about incorporating APDM’s technology into your upcoming research study and view recent publications please visit www.apdm.com.

1. McKay, et al. “Longitudinal assessment of leg motor activity and sleep patterns in infants with and without Down syndrome.” Infant Behavior and Development. 2006

2. Smith, et al. “Sample entropy identifies differences in spontaneous leg movement behavior between infants with typical development and infants at risk of developmental delay.” Technologies. 2017

3. Featured photo by Colin Maynard on Unsplash