Independent Mobility in Infants with Down Syndrome: Characterizing Locomotor Development and Feasibility of Body-Weight Support Intervention

1. Ellen Sutter (Boston University)
2. Ashley Collimore-Doherty (Boston University)
3. Erin Wilkerson (Boston University)
4. Nicole Baumer (Sie Center for Down Syndrome, Children's Hospital Colorado)
5. Jana Iverson (Boston University)

Correspondence: esutter@bu.edu

Independent locomotion has cascading impacts on overall infant development. Infants with Down syndrome (DS) attain locomotor milestones later, potentially missing developmental opportunities afforded by independent and upright mobility. Moreover, little is known about how infants with DS use locomotor skills in their daily lives after acquisition, which could influence opportunities for exploration and learning. To address these gaps, we completed two studies to 1) characterize how infants with DS use emerging locomotor skills (e.g. crawling, walking) in everyday play and 2) determine feasibility of an in-home mobility intervention for infants with DS. The first study was a longitudinal observational study of infants with DS (n = 13). We used behavioral video coding to investigate locomotion quantity and type during play, and changes with acquisition of new motor skills. Locomotion quantity was compared to that of 25 typically-developing infants. We found that infants with DS spent less time locomoting than typically-developing infants, and their locomotion time changed less with age and motor skill level (p < 0.05). Infants with DS also continued to rely on floor mobility skills even after attaining upright locomotor skills. These differences have potential implications for motor skill learning and development and indicate a need for interventions that promote independent mobility on a similar timeline as same-age peers.

The Portable Mobility Aid (PUMA, Enliten LLC) body-weight support harness is a promising and innovative approach to facilitate mobility in infants with motor delays. In our second study, we aimed to evaluate the feasibility and acceptability of a one-month caregiver-delivered intervention with the PUMA for infants with DS (n = 6, ages: 16.4 - 24.9 months). Caregivers were instructed to use the system during play for 30 minutes a day, 5 days per week. We measured adherence (number of sessions completed) and assessed motor skills practiced by the infants during the PUMA play sessions with caregiver surveys. Caregivers also completed an acceptability survey at the end of the intervention period. 4/6 caregivers completed >95% of the prescribed sessions with their infants. All infants practiced mobility skills in the PUMA that they could not yet perform independently, most commonly pulling to stand (52.63 - 100% of sessions) and standing (77.78 – 100% of sessions). Most caregivers reported that the PUMA was easy to use and felt comfortable using it at home on their own, and all six caregivers reported that the PUMA had an impact on their child’s motor skills. These findings are an important first step in evaluating the PUMA as an early mobility intervention for infants with DS and support a large-scale trial. Future work will evaluate the impact of the PUMA intervention on motor skill acquisition and other developmental domains.