Tracts in the limbic system show microstructural alterations post COVID-19 recovery

Area of Science:

• Neuroscience
• Radiology
• Infectious Diseases

Background:

• Long COVID is associated with persistent neurological symptoms such as delirium, memory loss, and fatigue.
• The underlying neurobiological mechanisms of these long-term sequelae remain poorly understood.

Purpose of the Study:

• To investigate microstructural white matter abnormalities in Indian COVID-19 survivors using diffusion MRI.
• To explore potential correlations between white matter changes and COVID-19 infection severity.

Main Methods:

• A cross-sectional study involving 44 COVID-recovered patients and 29 healthy controls in New Delhi.
• Deterministic whole-brain tractography was used to analyze 20 white matter tracts, comparing fractional anisotropy and diffusivity measures.

Main Results:

• Statistically significant microstructural differences were observed in the uncinate fasciculus, cingulate, and arcuate fasciculus of COVID survivors (P < 0.01).
• White matter diffusion measures correlated with COVID-19 infection severity, though no significant differences were found between hospitalized and non-hospitalized patients.
• Affected tracts are part of the limbic system and orbitofrontal cortex, crucial for memory and emotion.

Conclusions:

• COVID-19 recovery is associated with white matter microstructural abnormalities, particularly within the limbic system.
• These alterations may represent a neuroimaging signature for Long COVID, linking to reported functional deficits.
• Findings highlight the limbic system as a key target for future research on the long-term impact of COVID-19.