COVID-19 could lead to a "silent wave" of neurological issues

The world should prepare for a “silent wave” of neurological complications stemming from the COVID-19 pandemic, according to a team of neuroscientists and clinicians at the Florey Institute of Neuroscience and Mental Health. 

In a paper published by IOS Press, the researchers describe the potential link between COVID-19 and increased risk of Parkinson’s disease. They are urgently calling for the availability of more accurate diagnostic tools to identify neurodegeneration early on, as well as a long-term monitoring approach for people who have been infected with SARS-CoV-2.

“Although scientists are still learning how the SARS-CoV-2 virus is able to invade the brain and central nervous system, the fact that it’s getting in there is clear,” said Professor Kevin Barnham. “Our best understanding is that the virus can cause insult to brain cells, with potential for neurodegeneration to follow on from there.”

The team reports that the neurological symptoms associated with COVID-19 have ranged from the loss of smell to much more severe symptoms, such as lack of oxygen to the brain, or hypoxia.

“We found that loss of smell or reduced smell was on average reported in three out of four people infected with the SARS-CoV-2 virus. While on the surface this symptom can appear as little cause for concern, it actually tells us a lot about what’s happening on the inside and that is that there’s acute inflammation in the olfactory system responsible for smell,” explained study co-author Leah Beauchamp.

Inflammation is known to play a major role in the progression of neurodegenerative diseases, and this link has been extensively studied in patients with Parkinson’s. Further research into neurodegenerative issues may prove critical for addressing the lasting health impacts of COVID-19 infection.

“We believe that loss of smell presents a new way forward in detecting someone’s risk of developing Parkinson’s disease early. Armed with the knowledge that loss of smell presents in around 90% of people in the early stages of Parkinson’s disease and a decade ahead of motor symptoms, we feel we are on the right track,” said Beauchamp.

By the time Parkinson’s disease is diagnosed, which is based on the loss of motor dysfunction, dopamine cells in the brain have already been lost to some degree. 

“By waiting until this stage of Parkinson’s disease to diagnose and treat, you’ve already missed the window for neuroprotective therapies to have their intended effect. We are talking about an insidious disease affecting 80,000 people in Australia, which is set to double by 2040 before even considering the potential consequences of COVID, and we currently have no available disease-modifying therapies,” said Professor Barnham.

The researchers hope to establish a simple, cost-effective test to identify people in the community at risk of developing Parkinson’s, or who are in early stages of the disease. The team has also developed two neuroprotective therapies that are currently under investigation.

“We have to shift community thinking that Parkinson’s is not a disease of old age. As we’ve been hearing time and time again, the coronavirus does not discriminate – and neither does Parkinson’s,” said Professor Barnham.

“We can take insight from the neurological consequences that followed the Spanish Flu pandemic in 1918 where the risk of developing Parkinson’s disease increased two to three-fold. Given that the world’s population has been hit again by a viral pandemic, it is very worrying indeed to consider the potential global increase of neurological diseases that could unfold down track.”

“The world was caught off guard the first-time, but it doesn’t need to be again. We now know what needs to be done. Alongside a strategized public health approach, tools for early diagnosis and better treatments are going to be key.”

The study is published in the Journal of Parkinson’s Disease.

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By Chrissy Sexton, Earth.com Staff Writer