Potential of APDM mobility lab for the monitoring of the progression of Parkinson's disease

Abstract

APDM's Mobility Lab system provides portable, validated, reliable, objective measures of balance and gait that are sensitive to Parkinson's disease (PD). In this review, we describe the potential of objective measures collected with the Mobility Lab system for tracking longitudinal progression of PD. Balance and gait are among the most important motor impairments influencing quality of life for people with PD. Mobility Lab uses body-worn, Opal sensors on the legs, trunk and arms during prescribed tasks, such as the instrumented Get Up and Go test or quiet stance, to quickly quantify the quality of balance and gait in the clinical environment. The same Opal sensors can be sent home with patients to continuously monitor the quality of their daily activities. Objective measures have the potential to monitor progression of mobility impairments in PD throughout its course to improve patient care and accelerate clinical trials.

Keywords: Mobility; Parkinson’s disease; inertial sensors; mobility lab; objective measures.

Figure 1

Sensors on body/photo of Opal

Figure 2

Example of measures calculated with Mobility Lab. A) Range of motion, velocity, and symmetry of arm swing during gait. B) Turning during gait includes measures of turning angle, turning duration, velocity, and number of steps to complete a turn.

Figure 3

Gait and Balance measures that differentiate subjects with PD and control subjects at different stages of disease severity (quantified by the PIGD subscore). Figure adapted from Dewey et al., [46]

Figure 4

Effect of levodopa on gait and balance measures, measured by the standardize response mean (Adapted from Curtze et al, [6]).

Figure 5

Change in group mean (±SEM) balance and gait measures over time in 12 subjects with early PD (denovo) and 12 age-matched control subjects over 18 months. Upper panel: turning duration and arm swing during gait, measured during the instrumented Timed-up and go over 18 months. Lower panel: medio-lateral sway dispersion and sway velocity during 2 minutes of quiet stance over 12 months.

Figure 6

Effect of DBS in GPi on balance (A. Medio-lateral sway dispersion) and gait (B. Stride velocity) in 12 patients with PD. Means (±SEM) are represented in the best state before surgery (ON levodopa medication) and in the best state after surgery (ON levodopa and ON DBS) 60–90 days after DBS surgery. Significant (p<.01) improvement of balance by reducing sway dispersion but no improvement in gait is shown.

Figure 7

Quality of turns measured across 7 days of continuous monitoring in 12 subjects with PD and 15 control subjects (Adapted from Mancini et al [48]). A) and B) box plots compare medians and interquartile range of quality of turning measures between the PD and control groups; C) Relationship between disease severity and quality of turns in the group with PD.