The clinical characteristics of Parkinson's disease patients with concomitant periodic limb movements in sleep

Abstract

The current study aimed to investigate the clinical characteristics of Parkinson's disease (PD) patients with concomitant periodic limb movements in sleep (PLMS). The clinical data of 36 PD patients who underwent polysomnography (PSG) in Beijing Tiantan Hospital from October 2018 to July 2022 were collected. Unified Parkinson's Disease Rating Scale 3.0 and Hoehn & Yahr (H-Y) stage were used to evaluate the disease severity. Patients were divided into two groups: the PLMS+group periodic limb movements in sleep index [(PLMSI)≥15 times/h] and the PLMS-group (PLMSI<15 times/h), using the PLMSI 15 times/h as the cut-off value. The clinical characteristics between the two groups were compared. There were 15 patients (42%) in the PLMS+group and 21 patients (58%) in the PLMS-group, among which 12 patients (12/15) in the PLMS+group and 9 patients (42.9%) in the PLMS-group had rapid eye movement sleep behavior disorder (RBD). The rate of RBD in PLMS+group was higher than that in PLMS-group (P<0.05). There was statistically significant difference in the blood folate level between the PLMS-group and PLMS+group [6.20 (5.14, 11.70) ng/ml vs 4.41 (3.07, 5.64) ng/ml] (P<0.01). Folate deficiency was more common in the PLMS+group, while no statistically significant differences were found in homocysteine and ferritin levels (both P>0.05). Four patients in the PLMS+group had falling experience, while 14.3% (3/21) patients in the PLMS-group had falling experience. Patients in the PLMS+group were more likely to fall. The PLMS+group had higher arousal index according to PSG [PLMS-group: 11.90 (9.10, 15.80) times/h; PLMS+group: 21.50 (19.35, 29.90) times/h] (P<0.05). No statistically significant differences in other sleep parameters were detected between the two groups (all P>0.05). Meanwhile, the apnea-hypopnea index (AHI) in both groups was higher than normal (<5 times/h), of which the PLMS-group was 9.80 (4.70, 22.20) times/h and the PLMS+group was 8.20 (1.70, 11.15) times/h, indicating that PD patients were more likely to experience sleep apnea and hypopnea. PD patients with PLMS had lower folate level, higher risk for falls, higher sleep arousal index, more sleep fragmentation, and higher prevalence of RBD.