Detection of Motor Dysfunction With Wearable Sensors in Patients With Idiopathic Rapid Eye Movement Disorder

Abstract

Patients with idiopathic rapid eye movement sleep behavior disorder (iRBD) are at high risk for conversion to synucleinopathy and Parkinson disease (PD). This can potentially be monitored by measuring gait characteristics of iRBD patients, although quantitative data are scarce and previous studies have reported inconsistent findings. This study investigated subclinical gait changes in polysomnography-proven iRBD patients compared to healthy controls (HCs) during 3 different walking conditions using wearable motor sensors in order to determine whether gait changes can be detected in iRBD patients that could reflect early symptoms of movement disorder. A total 31 iRBD patients and 20 HCs were asked to walk in a 10-m corridor at their usual pace, their fastest pace, and a normal pace while performing an arithmetic operation (dual-task condition) for 1 min each while using a wearable gait analysis system. General gait measurements including stride length, stride velocity, stride time, gait length asymmetry, and gait variability did not differ between iRBD patients and HCs; however, the patients showed decreases in range of motion (P = 0.004) and peak angular velocity of the trunk (P = 0.001) that were significant in all 3 walking conditions. iRBD patients also had a longer step time before turning compared to HCs (P = 0.035), and the difference between groups remained significant after adjusting for age, sex, and height. The decreased trunk motion while walking and increased step time before turning observed in iRBD may be early manifestations of body rigidity and freezing of gait and are possible prodromal symptoms of PD.

Keywords: Idiopathic REM sleep behavior disorder; gait; prodromal stage; quantitative measurement; wearable sensors.

FIGURE 1

Location of sensors on the body.

FIGURE 2

Comparison of gait measures between groups under different walking conditions. (A–I) Group differences in stride length (A), stride velocity (B), stride time (C), stride length asymmetry (D), stride length variability (E), range of motion of the trunk in the sagittal plane (F), peak angular velocity of the trunk in the sagittal plane (G), range of motion of the trunk in the horizontal plane (H), and step time before turn (I) between iRBD patients and HCs under the usual pace, fast pace, and dual-task walking conditions.