title: Unobtrusive monitoring of the longitudinal evolution of in-home gait velocity data with applications to elder care.
abstract: Gait velocity has repeatedly been shown to be an important indicator and predictor of both cognitive and physical function, especially in elderly. However, clinical gait assessments are conducted infrequently and cannot distinguish between abrupt changes in function and changes that occur more slowly over time. Collecting gait measurements continuously in-home has recently been proposed and validated to overcome these clinical limitations. In this paper, we describe the longitudinal analysis of in-home gait velocity collected unobtrusively from passive infrared motion sensors. We first describe a model for the probability density function of the in-home gait velocities. We then describe estimation of the evolution of the density function over time and report empirically determined algorithm parameters that have performed well over a wide variety of different gait velocity data. Finally, we demonstrate how this approach allows detection of significant events (abrupt changes in function) and slower changes over time in gait velocity data collected from a sample of two elderly subjects in the Intelligent Systems for Assessing Aging Changes (ISAAC) study.
authors.affiliation: Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA. USA. austidan@bme.ogi.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Austin
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Hayes
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kaye
authors.forename: Nora
authors.initials: N
authors.lastname: Mattek
authors.forename: Misha
authors.initials: M
authors.lastname: Pavel
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000465:Algorithms; D005260:Female; D005684:Gait; D005853:Geriatrics; D006801:Humans; D008297:Male; D015233:Models, Statistical; D018670:Monitoring, Ambulatory / Q000379:methods*; D009068:Movement; D009735:Nursing Homes; D011336:Probability; D013997:Time Factors; D016138:Walking