Detection of Gait and Postures Using a Miniaturized Triaxial Accelerometer-Based System: Accuracy in Patients With Mild to Moderate Parkinson's Disease

Dijkstra B, Kamsma YP, Zijlstra W. Detection of gait and postures using a miniaturized triaxial accelerometer-based system: accuracy in patients with mild to moderate Parkinson's disease.ObjectiveTo examine whether gait and postures can accurately be detected with a single small body-fixed device in patients with mild to moderate Parkinson's disease (PD).DesignResults of a triaxial accelerometer-based method were evaluated against video observation scores (criterion measure). Study 1: Subjects performed basic mobility-related activities (walking, lying, sitting, standing) in a fixed and free sequence. Study 2: Subjects were monitored while doing similar activities as in study 1 and while doing usual domestic activities.SettingStudy 1: Standardized set-up in a movement laboratory. Study 2: Home environment.Participants(N=37) Study 1: Patients with PD (n=32; mean age ± SD, 67.3±6.6y; mean disease duration ± SD, 6.1±3.4y). Study 2: Patients with PD (n=5; mean age ± SD, 76.0±7.3y; mean disease duration ± SD, 3.8±4.7y).InterventionsNot applicable.Main Outcome MeasuresThe degree of correspondence between the monitor and the video observation for the duration of each activity. Overall agreement, sensitivity, specificity, and positive predictive values were calculated.ResultsStudy 1: Overall agreement ranged between 69.8% and 90.8% (fixed sequence) and 57.5% and 96.9% (free sequence). Study 2: Overall agreement ranged between 60.0% and 89.2%. Lying, sitting (home), and walking were detected most accurately with mean sensitivity varying from 81.7% to 99.9%. Lower values were found for sitting (laboratory), standing, and shuffling.ConclusionsThis triaxial monitor system is a practical and valuable tool for objective, continuous evaluation of walking and postures in patients with mild to moderate PD. Detection of sitting and standing requires further fine-tuning.