Sleep and other non-motor parameters in patients with Parkinson’s Disease

Abstract

Background: Parkinson’s Disease (PD) is a progressive neurodegenerative disease that leads to both motor and non-motor manifestations. Early research focused mainly on the motor symptoms in PD as they were the most apparent during early manifestations, while non-motor symptoms were generally neglected. However, over the past decade, non-motor symptoms in PD have gained more recognition for their negative impact on the quality of life (QOL) in patients with PD. The non-motor symptoms in PD consist of sleep disturbances, cognitive impairment advancing to dementia, autonomic dysfunctions, sensory disorders, and neuropsychiatric symptoms. Among these, sleep disturbances have a high prevalence of 74- 94% in PD and may severely impact the QOL, mental and physical health and behaviour of patients with PD. Common therapeutic strategies for PD consist of antiparkinsonian drugs. However, during the mid to late stages of the disease, a surgical intervention using deep brain stimulation (DBS) is performed in patients who have a decreased sensitivity to available medication or patients with drug induced complications.

Study Aims and Objectives: This study aims to compare subjective and objective sleep measures in patients with PD following DBS with PD patients who have not undergone DBS (non-DBS) as well as to determine the relationship between sleep parameters and other PDrelated non-motor and motor symptoms such as cognitive function, depression, fatigue, pain, physical activity and light exposure.

Methods: Twenty-two patients with PD were recruited and divided into two groups; DBS (n = 7) and non-DBS (n = 15). All patients completed the sleep and general health questionnaires that also assessed other PD- related non-motor symptoms. Nineteen of the patients wore both the wrist and hip-mounted activity monitors. Eight patients completed polysomnography. Sleep parameters assessed included: sleep quality, sleep efficiency, total sleep time, latency, and wake after sleep onset (WASO). Unified Parkinson’s Disease rating scale scores and Hoehn and Yahr stages were also obtained from all patients.

Results: Overall, subjective sleep measures comparing DBS and non-DBS groups showed that the DBS group had greater excessive daytime dysfunction (p = 0.044) and fatigue (p = 0.017). There were no significant differences seen in PSQI global scores, or its components except the DBS group exhibited greater PSQI daytime sleepiness compared to the non-DBS group (p = 0.016). The DBS group also presented with a significantly higher prevalence of RLS compared to the non-DBS group (n = 29 % vs n = 13 %) (p = 0.0087), however the non-DBS group had more severe RLS according to the International Restless Legs Study Group Severity Scale scores. There were no significant differences seen in the objective sleep parameters (actigraphy and PSG) and physical activity patterns between the two groups except NREM stage 3 was higher in the non-DBS group (p = 0.029). Among the PD-related non-motor symptoms in PD, the DBS group showed higher BDI II scores compared to the non-DBS group (p = 0.0143). No significant differences were seen for pain, cognitive dysfunction, physical activity, and light exposure between the two groups, however both groups spent an increased amount of time of 83% in sedentary behaviour. Negative correlations were observed between wrist actigraphy sleep efficiency and pain (r = -0.647, p = 0.011) and wrist actigraphy total sleep time and pain (r = -0.793, p = 0.001). A positive correlation was observed between hip actigraphy sleep latency and moderate physical activity (r = 0.576 , p = 0.011). None of the other relationships between sleep parameters and other PD-related non-motor symptoms and physical activity were significant.

Conclusion: In conclusion, the non-DBS group had better sleep quality compared to the DBS group, which was supported by the non-DBS group having better subjective sleep measures compared to the DBS group. This was further corroborated by the non-DBS group scoring higher in slow wave sleep as well as pain and moderate physical were also associated with sleep, suggesting that these relationships may affect sleep in PD.