Patients diagnosed with COVID-19 may show neurological symptoms, such as loss of smell, delirium and cognitive impairment. Mayo Clinic researchers are investigating these side effects to determine whether being infected with COVID-19 influences development or progression of Alzheimer’s disease and Alzheimer’s disease-related dementias.

While COVID-19 is primarily regarded as a respiratory disease, brain scans and neuropathological studies confirm brain abnormalities in some patients infected with COVID-19. In addition, a recent Mayo study revealed that approximately half of patients hospitalized with COVID-19 have elevated levels of neurofilament light in their blood. This protein is present only in neurons, which carry and transmit electrical signals throughout the nervous system, and its detection in blood indicates neuronal injury.

To examine that finding further, a team led by Leonard Petrucelli, Ph.D., a Mayo Clinic molecular neuroscientist, and James Meschia, M.D., a Mayo Clinic neurologist, is poised to investigate key questions about the effects of COVID-19 on the brain and assess long-term neurological implications of COVID-19 infection. Dr. Petrucelli is the Ralph B. and Ruth K. Abrams Professor of Neuroscience.

Adults 65 and older are especially vulnerable to COVID-19 and at higher risk of developing Alzheimer’s disease-related dementias.

The researchers plan to study:

•Blood neurofilament light protein.

•Other proteins associated with Alzheimer’s disease, such as tau and beta amyloid.

•Changes in cognition, behavior and daily function related to neurodegenerative disorders, which may be unmasked or accelerated by COVID-19.

Imaging for markers of brain neuroinflammation and beta amyloid pathology may help researchers determine whether neuroinflammation associated with COVID-19 triggers or accelerates the buildup of beta amyloid.