Long-term effects are seen with many flu-like diseases, and the local medical leaders will aid research to determine their seriousness.
The article, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, cites decades of scientific evidence suggesting it is very likely that COVID-19 will have long-term effects on the brains and nervous systems of its survivors. The Alzheimer’s Association is helping launch a study to better understand how COVID-19 could increase the risk of diseases such as Alzheimer’s and psychiatric illnesses, including depression.
He said research is needed but that chronic consequences of COVID-19 could impact many individuals’ quality of life and independence and it is likely that even mild infections will have some negative long-term effects on the brain.
“The under-recognized medical history of these viruses over the last century suggests a strong link to brain diseases that affect memory and behavior,” said Maria Carrillo, Alzheimer’s Association chief science officer and a co-author on the article.
The study will consist of work from a consortium of scientific experts representing over 30 countries, according to a statement from UT Health. The Alzheimer’s Association, a Chicago-based nonprofit dedicated to Alzheimer’s care, support and research, is putting about $300,000 toward the initial funding, said Heather Snyder, its vice president of medical and scientific relations.
These experts will enroll study participants from a pool of millions of confirmed COVID-19 cases documented in hospitals worldwide. A second group will consist of people who are participating in other international COVID-19 studies.
Participants will be evaluated at an initial appointment and again at six, nine, and 18 months. They will be tested on their cognition, behavior, and brain activity measured by magnetic resonance imaging.
Proof that the virus affects the brain lies in the COVID-19 symptom of anosmia, or loss of smell, said consortium member Dr. Sudha Seshadri, professor of neurology in the Long School of Medicine at UT Health San Antonio, director of the Glenn Biggs Institute, and a senior author of Tuesday’s article.
“Some of the respiratory viruses [like COVID-19] have an affinity for nervous system cells,” Seshadri said. “Olfactory cells [our smell nerve cells] are very susceptible to viral invasion and are particularly targeted by SARS-CoV-2, and that’s why one of the prominent symptoms of COVID-19 is loss of smell.”
The olfactory bulb – the bundle of nerves that transmit smell information from the nose to the brain – connects with the hippocampus, a brain structure primarily responsible for short-term memory. The hippocampus also is one of the first areas to be affected by Alzheimer’s disease.
The path the SARS-CoV-2 virus takes when it invades the brain leads almost straight to the hippocampus, de Erausquin said.
“That is believed to be one of the [reasons for] the cognitive impairment observed in COVID-19 patients,” he said. “We suspect it may also be part of the reason why there will be an accelerated cognitive decline over time in susceptible individuals.”