Long Covid: study points to brain changes – 11/26/2023 – Balance and Health

People with long-lasting Covid symptoms show patterns of changes in the brain that are different from patients who have fully recovered or those who have never been diagnosed with the infection.

This is what research presented at the annual meeting of the Radiological Society of North America (RSNA), which takes place until next Wednesday (29), in Chicago (USA) shows. It is the first comparative study with these three distinct groups, according to the authors.

Following Covid-19 infection, up to 25% of patients may develop a condition commonly called “long Covid”, which includes a wide range of symptoms such as fatigue, difficulty concentrating (“brain fog”), change in smell or taste, joint or muscle pain, shortness of breath, digestive symptoms, among others.

These symptoms can persist for weeks, months or even years after infection, as several studies have shown.

In October, another study, published in the journal Cell, proposed another explanation for some cases of long Covid, based on findings that serotonin levels were lower in people with the condition.

Researchers at the University of Pennsylvania suggested that the reduction in serotonin is triggered by remnants of the virus that persist in the intestine. The decrease in serotonin could especially explain memory problems and some neurological and cognitive symptoms of long Covid.

However, the basis of this condition is still poorly understood. According to the authors of the study presented in Chicago, diffusion microstructure imaging (DMI), a new magnetic resonance technique, could be a promising approach to advance this field.

DMI analyzes the movement of water molecules in tissues. By studying how water molecules move in different directions and speeds, DMI can provide detailed information about the microstructure of the brain.

According to Alexander Rau, one of the study’s authors and resident physician at the Departments of Neuroradiology and Diagnostic and Interventional Radiology at the University Hospital Freiburg (Germany), the technique can detect even very small changes in the brain, not detectable by conventional MRI.

Rau and colleagues compared brain MRI scans from three groups: 89 patients with long Covid, 38 patients who contracted Covid-19 but reported no long-term subjective symptoms, and 46 healthy patients with no history of Covid-19.

The researchers first compared the brain macrostructure of these three groups to test for atrophy or any other abnormalities. Then they used DMI to gain deeper insight into the brain.

The three groups underwent whole-brain analyzes to assess the spatial distribution of possible changes and associations with clinical data, including long-term Covid symptoms such as fatigue, cognitive impairment or smell.

The results did not show loss of brain volume or any other lesions that could explain the symptoms of long Covid. However, Covid-19 infection induced a specific pattern of microstructural changes in various regions of the brain, and this pattern differed between those who had long-term Covid and those who did not manifest symptoms.

“This study provides in vivo insight into the impact of Covid-19 on the brain,” said Rau, during the presentation.

The findings revealed a correlation between microstructural changes and symptom-specific brain networks associated with problems with cognition, smell and fatigue.

“The expression of post-Covid symptoms was associated with specific affected brain networks, suggesting a pathophysiological basis of this syndrome,” said Rau.

The researchers hope to re-examine the patients in the future, recording both clinical symptoms and changes in the brain’s microstructure.

Despite the results, it remains unclear why some people develop long Covid and others do not, although previous studies have identified risk factors including female sex, older age, higher body mass index, smoking, pre-existing comorbidities, and hospitalization or care. previous intensives.