Cyclic Alternating Pattern of EEG Activities and Heart Rate Variability in Parkinson's Disease Patients during Deep Sleep

Background: Sleep disturbance and autonomic dysfunction are often found in Parkinson's disease (PD) patients, but little is known about changes in cyclic alternating patterns (CAPs) of electroencephalographic (EEG) activities and heart rate variability (HRV) during deep sleep in PD patients.Objectives: To investigate changes in EEG activities and HRV during CAPs and non-CAPs (NCAPs) of N3 sleep in PD patients.Methods: Polysomnographic (PSG) examinations were carried out on 18 PD patients and 18 healthy controls, and power spectral analysis of EEG activities and HRV during CAPs and NCAPs (the segment of sleep without CAPs for more than 60 seconds) of N3 sleep were carried out.Results: The percentages of N3 sleep with CAPs and CAP A1, as well as the CAP A1 index in the PD patients, were significantly smaller compared with the healthy controls. In addition, the power of alpha waves in NCAPs was significantly higher, while the powers of delta waves in Phase A and B of CAP A1 and A3, and NCAPs were significantly smaller. Furthermore, the durations of total delta waves and delta waves with an amplitude >= 75 mu V were significantly shorter, and the low frequency (LF) power of HRV during CAPs and the LF/high frequency (HF) HRV ratio during both CAPs and NCAPs were significantly smaller.Conclusions: The changes documented in EEG activities and HRV in PD patients during CAPs and NCAPs of N3 sleep compared with healthy controls suggest that N3 sleep quality and sympathetic function are compromised in PD patients.