Emerging research suggests that long Covid may cause distinct changes in the brain, potentially explaining the persistent neurological symptoms reported by many patients, the Daily Mail reports.
A new study has identified reduced levels of protective proteins and increased inflammation in the brains of individuals with long Covid—biological changes that have also been associated with conditions like dementia.
The study, published in the journal PLOS One, involved 17 participants aged 25 to 60 who had previously contracted COVID-19 at least six months prior. Of the participants, 10 were experiencing symptoms of long Covid while seven served as healthy controls. Most of the participants were female, and the average age was 42.
Researchers conducted interviews to assess ongoing symptoms such as brain fog, memory issues, fatigue, anxiety, and depression. Participants also underwent cognitive testing to evaluate language skills, memory, problem-solving abilities, and concentration. Blood samples were taken to measure levels of inflammatory markers and the stress hormone cortisol.
According to lead author Dr. Michael Lawrence, a neuropsychologist at Corewell Health in Michigan, this is the first controlled study to document specific neurocognitive changes in individuals with long Covid.
“To our knowledge, this is the first controlled study that shows specific self-reported neurocognitive and central nervous systems changes in long COVID patients, which validates the symptoms they’ve been experiencing,” he said.
One key finding was that long Covid patients had 33% lower levels of nerve growth factor (NGF)—a protein critical for maintaining healthy neurons. Low NGF levels have been previously linked to neurological conditions such as Alzheimer’s disease and multiple sclerosis.
Additionally, long Covid patients showed 50% higher levels of interleukin 10, a protein involved in immune response. While typically anti-inflammatory, elevated interleukin 10 can sometimes result in increased inflammation within the brain. Nine out of 10 long Covid participants exhibited high levels of inflammatory markers, compared to only one in the control group.
Cognitive testing also revealed that long Covid participants scored 30% lower on language processing tasks and were more likely to report diminished quality of life and general discomfort. The researchers suggest that this combination of inflammation and reduced neuroprotective proteins may affect brain regions involved in language, pain regulation, and emotional well-being.
Long Covid is a complex condition with a wide range of symptoms, including fatigue, shortness of breath, joint pain, and cognitive difficulties such as memory loss or difficulty concentrating—often described collectively as “brain fog.” An estimated 17 million Americans are believed to be living with long Covid, making it a growing area of clinical concern.
The authors acknowledge the limitations of the study, including its small size and the lack of diversity among participants. However, they view the findings as a foundation for future research. Larger studies are planned to confirm these results and explore potential treatment strategies.
Dr. Judith Arnetz, co-author and professor emerita at Michigan State University, emphasized the importance of early recognition:
“Although this is a small study and more work needs to be done, from a clinical application standpoint, physicians potentially can identify individuals who are struggling sooner and provide wrap-around care that could be helpful to them.”
Dr. Lawrence added that interventions such as speech therapy, psychological support, and medications targeting fatigue and cognitive symptoms could form part of a comprehensive treatment plan for long Covid patients.
While the study does not establish a direct link between long Covid and dementia, the similarities in biological markers suggest a need for ongoing investigation into long-term neurological impacts.
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