Validation of 24-hour ambulatory gait assessment in Parkinson's disease with simultaneous video observation

Steven T Moore,Bandar Hakim,Hamish G Macdougall,Valentina Dilda

doi:10.1186/1475-925x-10-82

Abstract

BackgroundParkinson's disease (PD) is a neurodegenerative disorder resulting in motor disturbances that can impact normal gait. Although PD initially responds well to pharmacological treatment, as the disease progresses efficacy often fluctuates over the course of the day, and clinical management would benefit from long-term objective measures of gait. We have previously described a small device worn on the shank that uses acceleration and angular velocity sensors to calculate stride length and identify freezing of gait in PD patients. In this study we extend validation of the gait monitor to 24-h using simultaneous video observation of PD patients.MethodsA sleep laboratory was adapted to perform 24-hr video monitoring of patients while wearing the device. Continuous video monitoring of a sleep lab, hallway, kitchen and conference room was performed using a 4-camera security system and recorded to hard disk. Subjects (3) wore the gait monitor on the left shank (just above the ankle) for a 24-h period beginning around 5 pm in the evening. Accuracy of stride length measures were assessed at the beginning and end of the 24-h epoch. Two independent observers rated the video logs to identify when subjects were walking or lying down.ResultsThe mean error in stride length at the start of recording was 0.05 m (SD 0) and at the conclusion of the 24 h epoch was 0.06 m (SD 0.026). There was full agreement between observer coding of the video logs and the output from the gait monitor software; that is, for every video observation of the subject walking there was a corresponding pulse in the monitor data that indicated gait.ConclusionsThe accuracy of ambulatory stride length measurement was maintained over the 24-h period, and there was 100% agreement between the autonomous detection of locomotion by the gait monitor and video observation.

Highlights

Parkinson’s disease (PD) is a neurodegenerative disorder that results from a progressive loss of dopaminergic neurons, predominantly within the substantia nigra
Stride length measures from the gait monitor were validated while walking along a 30-m hallway in healthy control subjects (N = 9; 5 males and 4 females; mean age 55 years (SD 2)), and PD patients (Table 1) prescribed oral levodopa (N = 4; 3 female and 1 male; 71 years (SD 6.4))
Stride length accuracy was maintained over the 24-h recording epoch (Figure 2); the mean error at the start of recording in the subset of PD patients (N = 3) participating in this part of the study was 0.05 m (SD 0, range 0.05-0.05 m) and at the conclusion of the 24-h period was 0.06 m (SD 0.026; range 0.03-0.08 m)

Summary

Introduction

Parkinson’s disease (PD) is a neurodegenerative disorder that results from a progressive loss of dopaminergic neurons, predominantly within the substantia nigra. One of the disabling clinical manifestations of PD is locomotor dysfunction; shortened stride length, increased variability of stride, reduced walking speed, and freezing of gait (a transient block of movement, when initiating gait, turning, or negotiating an obstacle). While dopamine replacement therapy (most commonly with the dopamine precursor levodopa) is initially effective, most patients develop motor fluctuations after 3 years of treatment [2]. Parkinson’s disease (PD) is a neurodegenerative disorder resulting in motor disturbances that can impact normal gait. PD initially responds well to pharmacological treatment, as the disease progresses efficacy often fluctuates over the course of the day, and clinical management would benefit from long-term objective measures of gait. In this study we extend validation of the gait monitor to 24-h using simultaneous video observation of PD patients

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Conclusion