title: Accuracy of a custom physical activity and knee angle measurement sensor system for patients with neuromuscular disorders and gait abnormalities.
abstract: Long-term assessment of ambulatory behavior and joint motion are valuable tools for the evaluation of therapy effectiveness in patients with neuromuscular disorders and gait abnormalities. Even though there are several tools available to quantify ambulatory behavior in a home environment, reliable measurement of joint motion is still limited to laboratory tests. The aim of this study was to develop and evaluate a novel inertial sensor system for ambulatory behavior and joint motion measurement in the everyday environment. An algorithm for behavior classification, step detection, and knee angle calculation was developed. The validation protocol consisted of simulated daily activities in a laboratory environment. The tests were performed with ten healthy subjects and eleven patients with multiple sclerosis. Activity classification showed comparable performance to commercially available activPAL sensors. Step detection with our sensor system was more accurate. The calculated flexion-extension angle of the knee joint showed a root mean square error of less than 5° compared with results obtained using an electro-mechanical goniometer. This new system combines ambulatory behavior assessment and knee angle measurement for long-term measurement periods in a home environment. The wearable sensor system demonstrated high validity for behavior classification and knee joint angle measurement in a laboratory setting.
authors.affiliation: Department of Orthopaedics, University Medicine Rostock, Doberaner Str. 142, 18057 Rostock, Germany. frank.feldhege@med.uni-rostock.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Feldhege
authors.affiliation: Department of Orthopaedics, University Medicine Rostock, Doberaner Str. 142, 18057 Rostock, Germany. anett.mau-moeller@med.uni-rostock.de.
authors.forename: Anett
authors.initials: A
authors.lastname: Mau-Moeller
authors.affiliation: Department of Orthopaedics, University Medicine Rostock, Doberaner Str. 142, 18057 Rostock, Germany. tobias.lindner@med.uni-rostock.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Lindner
authors.affiliation: Institute of Computer Science, University of Rostock, Albert-Einstein-Str. 22, Rostock 18059, Germany. albert.hein@uni-rostock.de.
authors.forename: Albert
authors.initials: A
authors.lastname: Hein
authors.affiliation: Medizintechnik Rostock GmbH, Zur Himmelspforte 1, Rostock 18055, Germany. a.markschies@mtronline.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Markschies
authors.affiliation: Department of Neurology, University Medicine Rostock, Gehlsheimer Str. 20, Rostock 18147, Germany. uwe.zettl@med.uni-rostock.de.
authors.forename: Uwe Klaus
authors.initials: UK
authors.lastname: Zettl
authors.affiliation: Department of Orthopaedics, University Medicine Rostock, Doberaner Str. 142, 18057 Rostock, Germany. rainer.bader@med.uni-rostock.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Bader
mesh_terms: D061725:Accelerometry / Q000295:instrumentation; D000203:Activities of Daily Living / Q000145:classification; D000328:Adult; D000465:Algorithms; D004867:Equipment Design; D005260:Female; D020233:Gait Disorders, Neurologic / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009103:Multiple Sclerosis / Q000503:physiopathology*; D016059:Range of Motion, Articular / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D055815:Young Adult