Year : 2022 | Volume
: 25 | Issue : 3 | Page : 338--339
Sleep disturbances in Parkinson's disease: Is it related to COVID-19?
Arunmozhimaran Elavarasi1, Manvir Bhatia2,
1 Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
2 Director of Sleep Medicine, Neurology Sleep Centre, New Delhi, India
Director of Sleep Medicine and Senior Neurologist, Neurology Sleep Centre, New Delhi
|How to cite this article:|
Elavarasi A, Bhatia M. Sleep disturbances in Parkinson's disease: Is it related to COVID-19?.Ann Indian Acad Neurol 2022;25:338-339
|How to cite this URL:|
Elavarasi A, Bhatia M. Sleep disturbances in Parkinson's disease: Is it related to COVID-19?. Ann Indian Acad Neurol [serial online] 2022 [cited 2022 Oct 6 ];25:338-339
Available from: https://www.annalsofian.org/text.asp?2022/25/3/338/347484
Parkinson's disease (PD) is a neurodegenerative disease and the commonest movement disorder. Though it is classified as a movement disorder and is diagnosed based on motor symptoms such as bradykinesia, rigidity, and tremors, it is associated with several other non-motor symptoms such as cognitive, sleep, autonomic, and olfactory dysfunction.
The authors have taken up the challenge of studying sleep disorders during the pandemic in patients with PD. Sleep-related disorders are difficult to study given the subjective nature of symptoms and the need for detailed history from a reliable bed partner or objective studies such as polysomnography which are time-consuming and cumbersome. These aspects limit the external validity of the data collected in the study. Using questionnaires, though may make the study more generalizable, would lead to inaccuracies in assessing the various sleep disorders.
Sleep disorders in PD can present as insomnia, obstructive sleep apnea, restless legs syndrome, periodic limb movement disorder, and (REM) Rapid eye movement sleep behavior disorder (RBD).
These can occur due to co-existing depression, motor fluctuations, off periods, and stiffness during sleep, nocturia, RBD, or anxiety. Sleep disorders can also be related to the underlying disease per se. Sleep is a relatively overlooked symptom of PD as the other symptoms often overshadow the sleep disorders. Sleep disorders occur in more than 60% of patients with PD.
A good night's sleep is essential to ensure productivity during the day. Disturbed or fragmented sleep leads to excessive daytime sleepiness and thus hampers the personal and professional life of the individual. Sleep is also important in the consolidation of memory, and sleep dysfunction antedates the development of various neurodegenerative conditions such as Alzheimer's disease.,
Desai et al. (AIAN 255.22) have reported a case-control study comparing 50 patients with PD and 50 age, gender, and BMI-matched controls. This was a cross-sectional study in which they compared the sleep parameters between the patients and controls using validated questionnaires.
They found that 88% of patients had one or more sleep disorders as compared to 28% of controls. This study was done during the COVID-19 pandemic; however, none of the patients or their home members have been reported to have had COVID-19.
The controls have been selected from hospital staff, friends, and relatives of patients. It is unknown if the selected hospital staff had shift work, especially during the COVID-19 pandemic when they were short-staffed due to various health-care workers getting infected. Other confounding factors such as nocturia, associated obstructive sleep apnea, motor fluctuations during sleep and anxiety due to disease status, COVID-19 pandemic per se, and health of other family members have not been considered. It is also unclear if the examiner assessing the participant was blinded to the disease status.
The various associated symptoms such as RLS and RBD have been assessed using validated questionnaires. However, they could have over or underestimated these in comparison to polysomnography, and the authors have pointed out these limitations. Future studies may be designed to overcome these limitations.
This paper has compared patients with PD with healthy controls. A study by Kumar et al., which included a multicenter cohort of 832 patients with PD, reported only 35% of patients with PD reporting sleep disturbances. This study did not have controls. In a study from Wuhan, the authors reported a 69% prevalence of sleep disorders in Chinese patients with PD in comparison to 44% of controls. They also found a significantly higher prevalence of poor sleep quality and depression in PD patients as compared to controls.
The authors of this paper have concluded that sleep disturbances have increased during the COVID-19 pandemic. In summary, this is a study comparing PD patients with controls done during the pandemic period. The setting in which the historical studies were done might have been different from the current study. In addition, several other confounding factors such as disease stage, associated comorbidities, medication status, and cognitive status might have been different from the older studies, which have not been considered or compared in this study. Thus, it may be difficult to conclude that the sleep disturbances had indeed increased during the pandemic in patients with PD. It would be interesting to know if this same cohort of patients would have a change in sleep-related parameters after the pandemic. A study by Saluja et al. reported an increase in insomnia during the COVID-19 pandemic in 31% of patients with PD as assessed by caregivers using a structured questionnaire. However, this study could be subject to recall bias.
In a study during the COVID-19 pandemic, compared with baseline, a study from Sweden found reduced sleep-related disturbances during the pandemic in patients with PD. This study had collected baseline ratings before the pandemic as a part of their registry, thus removing an element of recall bias.
The subject of sleep in patients with PD has been a neglected field. It is essential to follow up patients evaluated during the pandemic to study their long-term follow-up status. In addition, it would be interesting to know the long-term neurologic outcomes of the participants in the control group who had RBD, which is known to be a premotor symptom of PD.
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