How well do Parkinson's disease patients turn in bed? Quantitative analysis of nocturnal hypokinesia using multisite wearable inertial sensors

Background: Nocturnal hypokinesia/akinesia is a distressing symptom in patients with Parkinson's disease (PD). However, it is difficult to accurately monitor these symptoms based on clinical interviews alone. Objectives: To quantitatively compare nocturnal movements of PD patients with their spouses by using multisite inertial sensors and to correlate these parameters with disease severity scores. Methods: Nocturnal movements in 19 PD couples (mild-moderate stage) were assessed and compared using wearable sensors (limbs and trunk) for one night at their homes. Nocturnal parameters included number, velocity, acceleration, degree, and duration of rolling over, number of getting out of bed, and limb movements. Each activity was compared to sleep diary, and video recording for accuracy. Results: PD patients significantly had fewer rolling over (p = 0.048), turned with smaller degree (p = 0.007), less velocity (p = 0.011), and acceleration (p < 0.001), but had more episodes of getting out of bed (p = 0.03, nocturia) when compared to their spouses. Moderate and significant correlations were observed between the mean duration of rolling over and the Unified Parkinson's Disease Rating Scale Axial score, and Nocturnal Akinesia Dystonia and Cramp Score. The number of leg movements (predominant side) significantly correlated with REM behavior disorder single-question screen. Episodes of nocturia correlated with total and bedtime levodopa equivalent dose. Several other correlations were also observed. Conclusion: Our study was able to demonstrate quantitatively the presence of nocturnal hypokinesia in PD patients. This problem correlated with daytime axial motor and nonmotor symptoms. Treatment strategy for PD should be based on a comprehensive review of both day- and nighttime symptoms. (C) 2015 Elsevier Ltd. All rights reserved.