Wearables capture patterns of activity, gait, tremors in Parkinson’s disease patients

Parkinson’s disease (PD) significantly impairs activity even when patients are in their natural environment, according to a recent real-world study.

“These new insights advance our understanding of the motor features of PD and could in the future provide valuable information to improve care and enhance the evaluation of therapies,” the researchers said. “Larger and longer-duration studies are required to replicate these findings and to evaluate how they change over time.”

A total of 17 PD patients (mean age 66.4 years, 41.2 percent women) participated in the present study. Activity and gait were measured using a wearable accelerometer device. Participants underwent in-clinic assessments with the Movement Disorder Society-Unified Parkinson Disease Rating Scale Part III, Timed Up-and-Go, and Ten-Meter Walk tests.

Afterwards, participants were instructed to continue wearing the sensors in the real world and complete a supplementary activity log. A parallel group of 17 non-PD controls was also included for reference (mean age 64.0 years, 76.5 percent women).

Device data showed that compared with healthy controls, PD patients spent significantly less active time per day. For instance, patients walked a median of only 0.9 hours per day, as opposed to 1.4 hours per day in controls (p=0.04). In contrast, PD patients spent similar amounts of time per day lying down (p=0.65), sitting (p=0.73), and standing (p=0.47) as controls. [NPJ Parkinsons Dis 2021;7:106]

Aside from impaired activity, the wearables likewise detected significant gait impairments in PD patients. In particular, they took significantly fewer median steps (4,980 vs 7,367 steps per day; p=0.04) and had worse step coordination (0.25 vs 0.30; p=0.01) than controls.

No such between-group differences were detected for step length (p=0.28), gait speed (p=0.47), and step duration (p=0.22).

The devices were also used to assess hand tremors, comparing patterns between the less- vs more-affected limb. The more heavily affected hand showed a significantly greater median tremor proportion per day as compared with both the less affected hand and with the right hand of a corresponding control (6.5 percent vs 2.2 percent and 1.6 percent; p=0.003 and p<0.001, respectively).

In absolute terms, the more affected hand of PD patients had tremors for a median of 1.6 hours per day, as opposed to only 0.5 hours per day in the less affected hand and 0.4 hours per day in controls. Notably, the researchers observed a link between activity and hand tremors in PD patients, such that amplitude tended to be highest during sitting intervals and lowest while lying down, when the wearers were likely asleep.

“Most wearable sensor studies in Parkinson’s disease have been conducted in the clinic and thus may not be a true representation of everyday symptoms and symptom variation,” the researchers said. “Our goal was to measure activity, gait, and tremor using wearable sensors inside and outside the clinic.”

“Importantly, our study analyses tremors at home and quantifies the duration, frequency, and amplitude of tremors experienced by individuals with PD over the course of their daily lives outside the clinic,” they added.