Impact of inability to turn in bed assessed by a wearable three-axis accelerometer on patients with Parkinson's disease

Difficulty turning over in bed is a common night-time symptom in Parkinson's disease (PD). We aimed to quantitatively evaluate overnight turnover movements using a three-axis accelerometer and to investigate whether inability to turn in bed is related to daytime sleepiness, sleep quality, and depressive mood in PD patients. We examined 64 patients with PD (mean age, 73.3±8.21 years; modified Hoehn-Yahr [mH-Y] stage, 3.0±1.0; disease duration, 7.2±6.3 years; unified Parkinson's disease rating scale [UPDRS], 36.9±18.3). Overnight monitoring of turnover movements using a wearable three-axis accelerometer was performed in all patients. Nocturnal kinetic parameters including total time recumbent, total time supine, number of turnover movements, and mean interval between turnover movements were obtained. Daytime immobility was assessed using the Barthel index (B-I), UPDRS, and mH-Y stage. Patients were also assessed with the Epworth Sleepiness Scale (ESS), Parkinson's Disease Sleep Scale-2 (PDSS-2), and Beck Depression Inventory (BDI). Number of turnover movements in bed correlated negatively with disease duration (r = -0.305; p