Objective: To investigate whether body-fixed sensor mobility metrics identify older adults without a diagnosis of Parkinson disease (PD) at risk for developing parkinsonism.

Background: Parkinsonism is common in the elderly, and predicts adverse health outcomes. In prior work we showed that mobility metrics from a body-fixed sensor are related to the severity of parkinsonism in older adults without PD. However, it is not known if these metrics identify older adults at risk for developing parkinsonism.

Methods: 683 ambulatory, community-dwelling older adults without parkinsonism were evaluated annually for four parkinsonian signs (bradykinesia, tremor, rigidity, parkinsonian gait) using a modified Unified Parkinson’s Disease Rating Scale. Subjects also wore a belt with a body-fixed triaxial accelerometer/gyroscope as they performed 3 motor tests (32 ft walk, standing with eyes closed, Timed Up and Go test [TUG]). Baseline measures were summarized into 12 gait scores including gait speed metrics, which quantified 5 subtasks including: a) walking, b) standing posture, plus 3 TUG subtasks: c) sit to stand transition, d) stand to sit transition, and e) turning. In a series of Cox proportional hazards models controlled for age, sex, education and race, we examined which gait scores were associated with incident parkinsonism (2 or more parkinsonian signs at a follow-up examination). Stepwise backwards elimination was performed to identify combinations of gait scores independently associated with incident parkinsonism.

Results: 139 out of 683 (20.4%) participants developed parkinsonism during 2.5 ± 1.28 years of follow-up. When modeled separately, 6 out of 12 gait scores were associated with incident parkinsonism. Two of 12 scores (stand to sit transition and turning scores) survived stepwise backward elimination, and were independently associated with incident parkinsonism (p=0.003 and p<0.001, respectively).

Conclusions: Mobility metrics derived from a wearable body-fixed sensor facilitate identification of older adults without PD at risk of developing parkinsonism.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/quantitative-mobility-metrics-from-a-body-fixed-sensor-predict-incident-parkinsonism-in-older-adults/