Pathways to self-initiated mobility: Adoption and use of mobility aids by young children with developmental disabilities

Abstract

Self‑initiated mobility is a critical driver of early childhood development, supporting autonomy, exploration, social engagement, and participation. As children acquire new mobility skills, they experience cascading developmental effects across motor, cognitive, linguistic, and social domains. For young children with developmental disabilities, however, opportunities for self-initiated mobility are often limited by physical impairments, inaccessible environments, and limited access to age‑appropriate mobility technologies. While increasing attention has been given to supporting mobility for children with disabilities at the same time as typically developing peers, important questions remain regarding how mobility aids function within children's everyday environments and how they impact physical development. This dissertation examines how mobility technologies, device configurations, and environments of use shape self‑initiated mobility experiences for young children with developmental disabilities. Drawing from engineering, rehabilitation science, biomechanics, and disability studies, mobility is conceptualized as an interaction among the child, technology, and the physical and social environment. Across four observational, experimental, and mixed-methods studies conducted in laboratory and community settings, this work evaluates three mobility aids designed for young children: modified ride‑on car (mROCs), the Permobil Explorer Mini powered mobility device, and an open‑area partial bodyweight support (PBWS) system. Although qualitative research has identified inaccessible surfaces and inadequate space as barriers to mobility aid use, quantitative evidence describing how environmental accessibility shapes mobility behavior has been limited. By integrating embedded sensors, geospatial tracking, and open-source accessibility data, we quantified community-based modified ride-on car use over a one-year period. Findings demonstrated that environmental accessibility influenced mobility intervention success, with children living in more pedestrian-friendly neighborhoods using their devices more frequently and traveling greater distances than children living in less accessible environments. These findings indicate that access to self‑initiated mobility for young children is shaped not only by device availability, but also by the accessibility of the surrounding built environment. Community-based mobility is frequently evaluated using caregiver reports and clinical assessments, yet objective sensing technologies offer opportunities to quantify mobility behavior in real-world settings. To advance measurement of community-based powered mobility, this study compared device-integrated data loggers, GPS trackers, and caregiver-reported activity logs using data from a randomized crossover trial involving two pediatric mobility devices. Sensor-based measures provided objective information regarding frequency, duration, and distance of use, while caregiver reports captured contextual information regarding participation, engagement, and non-locomotor interactions with devices. These findings demonstrate that no single measurement approach fully characterizes self-initiated mobility and support combining engineering-based sensing methods with caregiver perspectives to evaluate mobility interventions in real-world settings. Concerns regarding the physical implications of supporting self‑initiated mobility, particularly related to posture, physical activity, and musculoskeletal development, remain a barrier to ON‑Time mobility. To address these concerns, children’s physical activity, posture, and biomechanical responses during play were examined using wearable sensors across multiple mobility conditions. In one study comparing play with and without partial bodyweight support, children demonstrated high levels of physical activity in both conditions, while PBWS supported increased time spent in upright postures across sessions. In a second study comparing unassisted mobility, PBWS, and powered mobility with static and dynamic seating configurations, children explored the largest areas when using powered mobility. Muscle activity was higher during PBWS and unassisted mobility than during powered mobility, and upright posture was highly variable across conditions but occurred most frequently for the greatest number of children when using powered mobility with a dynamic seat configuration. Together, these findings show that technologies supporting self‑initiated mobility redistribute physical effort and postural demands rather than reduce activity, and that different devices afford distinct movement opportunities aligned with different developmental and therapeutic goals. Caregiver perspectives provided critical context for understanding how mobility aid use is experienced and integrated in daily life. Across interviews conducted before and after children’s exposure to multiple mobility aids, caregivers described enthusiasm for mobility technologies and perceived benefits for children’s autonomy, exploration, and development. At the same time, families navigated societal and clinical norms that prioritize independent walking, along with practical challenges related to device fit within the home, feasibility of use, and access. Systemic factors, including insurance coverage, cost, and provider support, were described as key enablers or barriers to supporting self‑initiated mobility. Caregivers emphasized that mobility aids were most successful when they aligned with family routines and supported participation across multiple settings. Taken together, this dissertation situates mobility for young children with developmental disabilities at the intersection of engineering, rehabilitation medicine, and disability studies. Across studies, children’s self‑initiated mobility experiences were shaped not only by device capabilities, but also by neighborhood accessibility, measurement practices, physical demands, and caregiver priorities. Considering these factors together underscores that supporting mobility requires attention to children’s lived experiences across environments rather than focusing solely on movement metrics or device performance. Across laboratory and community settings, these findings emphasize the importance of accessible environments, mixed‑method assessment approaches, and family‑centered practices to support self‑initiated mobility for young children with developmental disabilities.