New Insights on Long COVID Symptoms

St. Paul, Minn., May 15 — Millions of individuals grappling with “long COVID,” particularly those facing persistent “brain fog” and extreme fatigue, received encouraging news from a recent study published on Thursday.

While the findings may seem intricate, researchers indicated that these issues seem to have biological and neurological underpinnings, suggesting that it’s not merely psychological.

Approximately 12 million people in the U.S. dealing with long COVID report various neurological symptoms, which can manifest as mental sluggishness, trouble concentrating, confusion, and memory issues long after they’ve recovered from the virus.

Patients describe as many as 200 different symptoms, but the most prevalent include brain fog, lingering tiredness, and breathlessness.

The neurological complications notably affect those who used to excel at multitasking, restricting their capacity to manage stress and diminishing their mental flexibility needed for work.

Since long COVID was first acknowledged, researchers have been striving to uncover a “biological mechanism” underlying this condition. Recent small-scale studies have highlighted changes in key brain chemicals among patients who continue to experience symptoms six months after their initial infection.

Research from Corewell Health in Grand Rapids and Michigan State University suggests that these findings lend support to the theory that biological factors contribute significantly to cognitive impairments in these patients.

This study represents the first attempt to directly examine inflammation in long COVID patients, strengthening the idea that the persistent brain fog and fatigue stem from identifiable biological causes rather than being solely psychological.

In 2023, over 6% of American adults reported experiencing long COVID symptoms—nearly 25 million individuals in total. Among them, about half have reported brain fog. This underscores a pressing need to develop effective health strategies.

The research, published in the multidisciplinary journal PLOS One, aimed to identify specific biomarkers and assess cognitive functions in patients classified as having long COVID, particularly those still suffering from brain fog months after infection with SARS-CoV-2.

The study involved 17 individuals with confirmed COVID diagnoses, including 10 with ongoing symptoms and a control group of seven who had fully recovered without lingering effects.

It was found that those experiencing symptoms had lower levels of nerve growth factor (NGF), a protein essential for neuron development and the maintenance of brain plasticity, which is critical for high-level cognitive functions requiring memory and adaptability.

Additionally, those patients displayed higher levels of interleukin-10, an anti-inflammatory protein crucial for immune regulation.

Participants also showed declines in “letter fluency,” a cognitive test designed to assess how quickly subjects can perform complex mental tasks that demand working memory and attention.

According to Dr. Bengt Arnetz, a professor and study co-author, the combined biological and neurological variations seen in long COVID patients are important. He emphasized the significance of these biological changes and their alignment with cognitive test results.

This is a groundbreaking discovery, as researchers have not previously investigated this specific relationship among confirmed COVID cases that have recovered from the infection.

Co-author Michael Lawrence, a clinical neuropsychologist, noted that while long COVID patients typically present normally on most neurocognitive tests, one measure—the letter fluency test—showed disparities. Patients often voice frustrations regarding their cognitive inefficiencies, feeling invalidated by the medical community due to the absence of clear biological explanations.

The study suggests issues related to processing speed could indicate the biological causes behind the cognitive challenges associated with long COVID.

Lawrence pointed out that interleukin-10’s connection to energy production might reveal a relevant relationship, providing objective evidence that aligns with patients’ experiences.

The findings hold the potential for targeted treatments if biomarkers can be identified early, allowing for a comprehensive approach to care.

Lawrence noted the importance of treating both mental and physical health as interconnected, suggesting improved mental health can alleviate reports of fatigue and pain. It’s essential to address these issues promptly for better outcomes.

Future research may explore how these biomarkers evolve over time and which treatments effectively alter these serum levels.