ALZHEIMER: Does long COVID promote cognitive decline?

With aging populations, dementia including Alzheimer’s disease is a growing health problem for older people around the world. COVID-19, along with possible other diseases characterized by brain inflammation, may have accelerated the incidence of cognitive impairment and dementia.

Inflammation is part of the chain of events leading to dementia

But that’s not all, other factors link COVID to the incidence of dementia:

• epidemiologists from the Centers for Disease Control and Prevention (US CDC) recall that just under a third of all COVID-19 cases have occurred in people aged 50 and over. However, it is this same group that also presents an increased risk of having or developing a neurodegenerative disease;
• patients with COVID-19 often report neurological symptoms such as memory impairment, “brain fog”, and loss of smell and taste – some symptoms persisting months after diagnosis, and characterizing long COVIDs;
• in particular, some scientists hypothesize that loss of smell also signals the onset of neurodegenerative processes that lead to both Alzheimer’s and Parkinson’s disease. This can arise from a person’s continued exposure to viruses and environmental toxicants that enter through the olfactory system (nose and nasal passages) – a concept known as

olfactory vector hypothesis for neurodegenerative diseases.

• SARS-CoV-2, the virus that causes COVID-19, is just one example of a virus that enters the body through the olfactory system;
• finally, previous research has also suggested that these patients are at higher risk of being diagnosed with dementia as a result of their acute infection.

These data led the Penn researchers to look at to what extent, and by what processes, COVID-19 could contribute to promoting premature cognitive decline.

To better understand the link between COVID-19 infection and neurocognitive decline, Dr. Xuemei Huang, professor of neurology, pharmacology, neurosurgery, radiology and physical therapy at Penn State Health and his multidisciplinary team will collect the data (history of COVID-19 infection, vaccination status, exposure to environmental toxins, medical history and lifestyle factors) from more than 500 participants including some with Alzheimer’s and Parkinson’s disease as well as biological samples (blood, skin biopsy and cerebrospinal fluid (CSF)) from participants having had and suffering from long forms of COVID.

The objective is to identify the biological signs (biomarkers) of neurodegenerative disorders and their evolution with COVID disease.

“We have a unique opportunity to study whether COVID-19 infection contributes to the progression of neurodegenerative diseases”