Update on COVID-19 and Parkinson’s disease

Latest Research on COVID-19 & Parkinson’s disease
UPDATE: This post (originally published in June) has been updated with the latest information available.
We will continue to keep this post up-to-date as new information develops.
As citizens of the world, we all continue to grapple with the COVID-19 pandemic. And as members of the Parkinson’s disease (PD) community, we continue to have specific concerns about COVID-19 and how it relates to PD. There is so much information out there, some of it misinformation, so it is important to rely on credible, trusted sources. In this post, I will cover the latest information (as of the date this was published) that investigates the relationship between PD and COVID-19.
What the research data tells us
Over the past eight months, physicians and scientists with expertise in PD have gathered their preliminary data on the experience of people with PD with COVID-19. These findings have been published in journals for others to learn from. This type of work is not unique to PD of course. Physicians are collating the data on how COVID-19 affects different people with the entire array of human conditions.
The data falls into two general categories:

Data regarding the lived experience of people with PD during the era of the pandemic COVID-19 (meaning the effect of the COVID-19 situation at large on their lives, not the effects of having contracted the virus)
Data regarding people with PD who have contracted COVID-19

Studies that investigate the relationship between PD and COVID-19

A study of anxiety during the pandemic was conducted in Iran. Patients with PD were asked to fill out questionnaires to rate their levels of anxiety. Questionnaires also contained questions related to PD and COVID-19. Data was collected from patients, caregivers and controls. The study showed that:

Levels of moderate and severe anxiety were significantly increased in PD patients over caregivers or controls.
20% of patients that were polled felt that the COVID-19 pandemic exacerbated their PD symptoms.
12% increased their PD medication use during the pandemic.

A study of the impact of the COVID-19 lockdown on PD patients was conducted in Egypt. Patients from the movement disorders clinic were assessed over the phone. The study demonstrated that:

Compared to controls, PD patients had significantly increased levels of stress, depression and anxiety along with decreased measures of quality of life, as compared to controls.
PD patients also reported a significant decline in physical activity as compared to pre-lockdown.

Two movement disorders groups – one in London and one in Italy – published a case series of 10 patients with advanced PD symptoms and COVID-19. The average age of the group was 78 with a 12-year duration of disease. The study showed that:

Most of the group that was studied required additional levodopa during their COVID-19 infection.
Anxiety, fatigue, orthostatic hypotension, cognitive impairment, and psychosis worsened during the infection.
Four patients (40%) died.
The case series was not large enough to statistically determine if risk of death is increased in people with advanced PD over other patients of the same age.

Another study took a different approach and did not report on the known cases of

Content provided by the American Parkinson Disease Association

Peripheral neuropathy and Parkinson’s disease

Today I will address the potential link between Parkinson’s disease and a common neurologic condition called peripheral neuropathy. This topic was submitted via the Suggest a Topic portal. I am grateful for your suggestions so please continue to let us know what you’d like to learn more about!
In order to understand what peripheral neuropathy is and what symptoms it can cause, we will briefly review the components of the nervous system.
Central nervous system vs. peripheral nervous system
Neurologic control of the body is very broadly divided into two systems – the central nervous system which consists of the brain and the spinal cord – and the peripheral nervous system which consists of the network of nerves that are outside the brain and spinal cord, and innervate the limbs and the organs of the body.
The peripheral nervous system is composed of three types of nerves: autonomic nerves, sensory nerves and motor nerves. Different types of nerves have varying diameters and are generally divided into those that are small and those that are large.

Autonomic nerves exert control over functions that are not under conscious direction such as respiration, heart function, blood pressure, digestion, urination, sexual function, pupillary response, and much more. This information is conveyed on small fibers.
Motor nerves carry information on limb movement from the brain and spinal cord to the limbs. This information is conveyed on large fibers.
Sensory nerves carry information on the various sensations felt by the limb to the brain and spinal cord. There are two main types of sensory nerves:

Pain and temperature fibers which are small fibers
Vibration and joint position sense fibers which are large fibers

The peripheral nervous system and Parkinson’s disease

It is well-established that the autonomic nervous system can be significantly affected in PD causing symptoms such as constipation, urinary dysfunction and orthostatic hypotension. The autonomic nerves that bring signals to the gut for example, can be directly affected by Lewy body-like accumulations and neurodegeneration. (This is not the only way that automatic functions of the body are affected in PD however. There can also be Lewy bodies and neurodegeneration in the parts of the brain that control these functions.)
What remains unclear is if motor and sensory nerves are also affected in PD.
What is peripheral neuropathy?
Peripheral neuropathy (PN) is a condition in which there is damage to peripheral nerves. Symptoms depend on which type of nerves are affected and can result in:

Weakness
Imbalance with walking
Numbness
Pain or paresthesias (sensations such as burning or tingling) in the limbs

The legs are more commonly affected than the arms because the nerves to the legs are longer than the arms and therefore more prone to damage.
Symptoms of peripheral neuropathy
The symptoms of PN can be non-specific, and a person therefore may not be able to distinguish on their own whether his/her symptoms are due to PN or another condition. PN, however, often results in specific findings on a neurologic exam, such as decreased sensation to pin prick or vibration or the lack of ability to discern which way a toe is being pointed without looking.

Content provided by the American Parkinson Disease Association