title: A novel algorithm for detecting active propulsion in wheelchair users following spinal cord injury.
abstract: Physical activity in wheelchair-bound individuals can be assessed by monitoring their mobility as this is one of the most intense upper extremity activities they perform. Current accelerometer-based approaches for describing wheelchair mobility do not distinguish between self- and attendant-propulsion and hence may overestimate total physical activity. The aim of this study was to develop and validate an inertial measurement unit based algorithm to monitor wheel kinematics and the type of wheelchair propulsion (self- or attendant-) within a "real-world" situation. Different sensor set-ups were investigated, ranging from a high precision set-up including four sensor modules with a relatively short measurement duration of 24 h, to a less precise set-up with only one module attached at the wheel exceeding one week of measurement because the gyroscope of the sensor was turned off. The "high-precision" algorithm distinguished self- and attendant-propulsion with accuracy greater than 93% whilst the long-term measurement set-up showed an accuracy of 82%. The estimation accuracy of kinematic parameters was greater than 97% for both set-ups. The possibility of having different sensor set-ups allows the use of the inertial measurement units as high precision tools for researchers as well as unobtrusive and simple tools for manual wheelchair users.
authors: Rehabilitation Engineering Lab, ETH Zurich, Switzerland; Spinal Cord Injury Center, University Hospital Balgrist, Switzerland. Electronic address: poppw@ethz.ch.
authors: Werner L
authors: WL
authors: Popp
authors: Spinal Cord Injury Center, University Hospital Balgrist, Switzerland.
authors: Michael
authors: M
authors: Brogioli
authors: Rehabilitation Engineering Lab, ETH Zurich, Switzerland.
authors: Kaspar
authors: K
authors: Leuenberger
authors: Spinal Cord Injury Center, University Hospital Balgrist, Switzerland.
authors: Urs
authors: U
authors: Albisser
authors: Swiss Paraplegic Center, Nottwil, Switzerland.
authors: Angela
authors: A
authors: Frotzler
authors: Spinal Cord Injury Center, University Hospital Balgrist, Switzerland.
authors: Armin
authors: A
authors: Curt
authors: Rehabilitation Engineering Lab, ETH Zurich, Switzerland.
authors: Roger
authors: R
authors: Gassert
authors: Spinal Cord Injury Center, University Hospital Balgrist, Switzerland.
authors: Michelle L
authors: ML
authors: Starkey
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D008297:Male; D055595:Mechanical Phenomena; D008875:Middle Aged; D009038:Motion; D013119:Spinal Cord Injuries; D060388:Support Vector Machine; D014910:Wheelchairs
keywords: Algorithm; Inertial measurement unit; Long-term; Machine learning; Monitoring; Propulsion; Spinal cord injury; Wheelchair