Passive biosensors successfully monitored neurologic disease-related symptoms among patients with multiple sclerosis (MS) both in-clinic and in the free-living setting, according to study results published in NPJ Digital Medicine.

Study researchers sought to evaluate the feasibility and correlation of wearable biosensors with traditional clinical disability measures in patients with MS. They recruited patients (N=25) with MS at the Brigham and Women’s Hospital for this ongoing, prospective longitudinal study. Cardiac and Activity Monitor (CAM) devices assessed acceleration, motion, heart rate, skin impedance, body temperature, and environmental exposures. The researchers assessed patients in the clinic on 3 occasions, in which patients completed tasks while wearing the CAM device at 9 body locations. Between the last 2 clinic visits, patients were given wrist, ankle, and sternum CAM devices and instructed to keep the devices on during the day and overnight for 8 weeks.

92 percent of participants were women, with an average age of 47 years and an average of 16 years since MS diagnosis. The mean expanded disability status scale (EDSS) score was 3.4 at baseline (range, 1.0-6.5).

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At the in-clinic assessment, of the 23 mobility categories, EDSS scores and MS functional composite-4 (MSFC-4) scores correlated with several biosensor-derived features,  including gait measurements of stance time (EDSS: r, 0.677; P =.01; MSFC-4: r, -0.546; P =.0070) and mobility activity time (EDSS: r, 0.814; ; MSFC-4: r, -0.859; P =.01 for both), and balance measurements of left-right sway distance (EDSS: r, 0.568; P =.05; MSFC-4: r, -0.532; P =.01) and anterior-posterior sway distance (EDSS: r, 0.503; P =.05; MSFC-4: r, -0.489; P =.05).

During the 8-week free-living assessment, study researchers collected about 50,000 hours of data. Several of the correlations with MSFC-4 scores were replicated, including gait stance time (r, -0.56; P =.0055), chest turn angle (r, 0.44; P =.0377), and average psychomotor vigilance task delay (r, -0.55; P =.0060). Findings indicated that additional measured features correlated with MSFC-4 scores, such as leg movement during sleep (r, -0.45; P =.0398) and overall idle minutes (r, -0.52; P =.0110).

The participants appeared to be satisfied with wearing the sensors, indicating that most (87%) would recommend others to participate in a similar body-sensor study. The most frequently reported difficulties were charging the sensors (40%) followed by ‘ease of use’ issues (27%).

This study was limited by its retention and participation rates (4 participants did not complete all clinic visits, 10 did not complete the final survey, and 7 were not highly compliant at wearing the sensors at home).

Study researchers concluded that the wearable biosensors provide “metrics with good correlations to complex MS scales traditionally assessed by a neurologist” and that findings “demonstrate the feasibility of applying passive biosensor measurement techniques to monitor disability in MS patients both in clinic and in the free-living setting.”


Chitnis T, Glanz BI, Gonzalez C, et al. Quantifying neurologic disease using biosensor measurements in-clinic and in free-living settings in multiple sclerosis. NPJ Digit Med. 2019;2(1):123. doi:10.1038/s41746-019-0197-7