DENVER — COVID-19 could trigger Alzheimer’s disease, according to new research. Memory loss and confusion were common symptoms among hundreds of older patients up to six months after infection.
The symptoms were linked to biological markers of brain injury, inflammation, and dementia. Those suffering cognitive decline after infection were prone to low blood oxygen, which can lead to the devastating neurological illness. Researchers say their study shows that COVID-19 could accelerate the development and onset of Alzheimer’s disease.
“We are starting to see clear connections between COVID-19 and problems with cognition months after infection. It is imperative we continue to study this population, and others around the world, for a longer period of time to further understand the long-term neurological impacts of COVID-19,” says Dr. Gabriel de Erausquin, of the University of Texas, in a statement.
The findings are based on almost 300 Argentinians with coronavirus who were tracked for three to six months. Symptoms occurred after brief exertion. The patients were also in poor overall physical condition. More than half showed persistent forgetfulness.
‘COVID-19 infections lead to lasting cognitive impairment, and even Alzheimer’s symptoms’
A quarter of the patients had additional cognition problems, such as loss of speech and executive skills. The problems were associated with ongoing smell dysfunction and not the severity of the original COVID-19 disease.
This sheds fresh light on short and long-term neuropsychiatric symptoms that have been reported after infection, including loss of smell and taste, and mental deficits with thinking and attention, known as “brain fog.” These symptoms may come on top of the respiratory and gastrointestinal complaints that accompany the virus.
For some, the symptoms persist. Experts are working to understand the mechanisms behind the phenomenon.
The study’s results were backed by a smaller study of patients in Greece. The implications are potentially shocking, the authors say. “These new data point to disturbing trends. They show COVID-19 infections lead to lasting cognitive impairment and even Alzheimer’s symptoms,” said Dr. Heather Snyder, vice president of Medical & Scientific Relations at the Alzheimer’s Association. “With more than 190 million cases and nearly 4 million deaths worldwide, COVID-19 has devastated the entire world. It is imperative that we continue to study what this virus is doing to our bodies and brains. The Alzheimer’s Association and its partners are leading, but more research is needed.”
Another study of 32 people previously hospitalized with mild to moderate COVID also found more than half were suffering cognitive decline. Multiple cognitive impairments and short-term memory loss were the most common symptoms. Worse thinking scores were linked to lower levels of oxygen during a six-minute walk test used to assess cardiopulmonary disease patients.
“A brain deprived of oxygen is not healthy, and persistent deprivation may very well contribute to cognitive difficulties,” explains study lead author Dr. George Vavougios, of the University of Thessaly in Greece. “These data suggest some common biological mechanisms between COVID-19’s dyscognitive spectrum and post-COVID-19 fatigue that have been anecdotally reported over the last several months.”
A third study of 310 older COVID patients in the U.S. who were previously cognitively normal identified higher levels of the protein tau in their brains. The rogue protein is one of the key indicators in Alzheimer’s. It gathers in tangles, killing neurons. Blood samples were taken from the participants, around half of whom were suffering confusion.
“These findings suggest patients who had COVID-19 may have an acceleration of Alzheimer’s-related symptoms and pathology. However, more longitudinal research is needed to study how these biomarkers impact cognition in individuals who had COVID-19 in the long term,” said lead author Professor Thomas Wisniewski of New York University.
All three studies were presented at the virtual Alzheimer’s Association International Conference in Denver.
Earlier this year an Oxford University study of more than half a million COVID patients in the U.S. found they were more prone to common psychological or neurological conditions. These included depression, dementia, psychosis, stroke, and Parkinson’s disease.
SWNS writer Mark Waghorn contributed to this report.