Background COVID-19 has affected global communities with multiple neurological complications in addition to other critical medical issues. COVID-19 binds to the host’s angiotensin-converting enzyme 2 (ACE2) receptors, which are expressed in the neurons and glial cells, acting as an entry port to the central nervous system (CNS). ACE2 receptors are abundantly expressed on dopamine neurons, which may worsen the prognosis of motor symptoms in Parkinson’s disease (PD). SARS-CoV-2 may lead to an indirect response via immune-mediated cytokine storms and propagate through the CNS leading to damage. In this systematic review, we aim to provide thorough analyses of associations between COVID-19 and neurological outcomes for patients with PD. Methods Using PRISMA statement 2020, a systematic review was conducted to isolate confirmed COVID-19 patients and analyze the PD-associated neurological outcomes using the following databases: PubMed, Science Direct, Google Scholar, and Cochrane databases. The following keywords were used “COVID19, SARS-CoV-2, Parkinson’s disease, Pandemic, Mortality.” A modified Delphi process was employed. Results Of the 355 studies located during the initial round of screening, 16 were included in the final synthesis. Of PD patients who tested positive for SARS-CoV-2, worsening motor symptoms and other viral-associated symptoms were reported. These symptoms included bradykinesia, tremors, gait disturbances, delirium and dementia, and severe spasms of arms and legs. Encephalopathy was presented in 2 of the included studies. Increased mortality rates were identified for hospitalized patients due to COVID-19 and PD as compared to other patient groups. Conclusion Patients with PD may experience substantial worsening of symptoms due to COVID 19. Given the novelty of neurological-viral associations, clinical studies in the future ought to explore the disease severity and neurological outcomes in COVID-19 positive patients with PD as compared to non-PD patients, in addition to understanding the role of ACE2 in increased vulnerability to contracting the infection and as a treatment modality.

Background: The novel Coronavirus (COVID 19) infection has affected the population with various medical issues including the underlying neurological comorbidities such as Parkinson disease. COVID 19 is found to bind with the host angiotensin-converting enzyme 2 (ACE2) receptors for viral entry. ACE2 receptors are normally expressed in various body surfaces as well as in the neurons and glial cells where they act as an entry port to SARS-CoV-2 infection to invade the central nervous system (CNS). ACE2 are also highly expressed in dopamine neurons which might worsen the outcome in terms of motor symptoms in PD with the treatment course. It may lead to an indirect response via immune-mediated cytokine storms and propagate through CNS leading to damage. Parkinsons disease has also been noticed due to certain post viral infections apart from COVID-19 such as, HSV, Influenza virus A, Measles virus, Cytomegalovirus and Mumps (Olsen et al, 2018). We aim to provide a thorough review on neurological outcomes and impact of COVID-19 in Parkinson disease. Methods: A systematic review was conducted to analyze the impact of COVID 19 in patients with Parkinson disease (> 21 yo). Systematic literature search was done using PubMed, Science Direct, Google Scholar and Cochrane databases. PRISMA guidelines were followed summarized in Fig. 3 for study acquisition. Results: Of the Parkinsons patients that were tested positive for SARS-CoV 2, worsening of motor symptoms were reported along with other COVID 19 symptoms (Fig. 4 and 5). These symptoms include bradykinesia, tremors, gait disturbances, delirium and dementia and severe spasms of arms and legs. Encephalopathy was also one of the main symptoms presented in two of the studies. Increased mortality rates were identified for those who were hospitalized due to COVID-19 and PD when compared to other patients. Conclusion: Parkinsons disease may experience substantial worsening of motor and non motor symptoms during COVID 19. Due to the novelty of the virus, studies were reported from recent years and further extensive studies are needed to explore more about the disease severity and neurological outcomes when compared to other non-PD patients. Authors identify this as a limitation for this paper. Additional studies are needed to understand the role of ACE2 in increasing vulnerability to viruses and role of ACE inhibitors as treatment modality.