Combining Accelerometer and GPS Features to Evaluate Community Mobility in Knee Ankle Foot Orthoses (KAFO) Users

Abstract

Orthotic and assistive devices such as knee ankle foot orthoses (KAFO), come in a variety of forms and fits, with several levels of available features that could help users perform daily activities more naturally. However, objective data on the actual use of these devices outside of the research lab is usually not obtained. Such data could enhance traditional lab-based outcome measures and inform clinical decision-making when prescribing new orthotic and assistive technology. Here, we link data from a GPS unit and an accelerometer mounted on the orthotic device to quantify its usage in the community and examine the correlations with clinical metrics. We collected data from 14 individuals over a period of 2 months as they used their personal KAFO first, and then a novel research KAFO; for each device we quantified number of steps, cadence, time spent at community locations and time wearing the KAFO at those locations. Sensorderived metrics showed that mobility patterns differed widely between participants (mean steps: 591.3, SD=704.2). The novel KAFO generally enabled participants to walk faster during clinical tests (Δ6Minute-Walk-Test=71.5 m, p=0.006). However, some participants wore the novel device less often despite improved performance on these clinical measures, leading to poor correlation between changes in clinical outcome measures and changes in community mobility (Δ6Minute-Walk-Test -ΔCommunity Steps: r=0.09, p=0.76). Our results suggest that some traditional clinical outcome measures may not be associated with the actual wear time of an assistive device in the community, and obtaining personalized data from real-world use through wearable technology is valuable.

Walk the Talk: Current Evidence for Walking Recovery After Stroke, Future Pathways and a Mission for Research and Clinical Practice

“…Alternatively, combining objective measurement with subjective report may help to understand why capacity often does not relate to performance and how to target this. Ecological momentary assessment, where real-time self-report data are used to provide information on the persons behavior, cognitions, affect, context, and other experiences, 25 could be combined with other technologies including accelerometers and global positioning systems 26,27 to provide a more holistic measure of walking performance.…”

Utilization of orthoses and assistive devices among a national sample of lower limb orthosis users

“… 4 A prior study examined orthosis use and community mobility using sensors attached to participants’ orthoses. 5 The authors found that LLO usage and time spent at community locations were not associated with self-reported mobility or performance test outcomes, suggesting that decisions to use LLOs for different activities are not based only upon a user’s mobility level. Further exploration into the situations for which people with LLOs choose to use them could offer insights into how LLO users make decisions to optimize their mobility.…”