Post-COVID Fatigue Linked to Reduced Blood Flow in Visual Processing centers of the Brain
New research reveals a consistent pattern of reduced blood flow-hypoperfusion-in the right occipital lobe among individuals experiencing persistent fatigue following a COVID-19 infection. The findings, published in PLoS One, suggest a neurological basis for the debilitating fatigue experienced by many in the post-COVID condition, perhaps opening avenues for targeted diagnostic and therapeutic interventions.
Millions worldwide continue to grapple with long-term symptoms after initial COVID-19 infection, collectively known as post-COVID condition or “long COVID.” Fatigue is among the most prevalent and disabling of these symptoms, considerably impacting quality of life and daily function. This study provides critical evidence linking this fatigue not to psychological factors alone, but to demonstrable changes in cerebral blood flow, specifically impacting areas of the brain responsible for visual processing and spatial awareness. Understanding these neurological underpinnings is crucial for developing effective strategies to alleviate the burden of post-COVID fatigue and improve patient outcomes.
Researchers utilized single-photon emission computed tomography (SPECT) to assess cerebral blood flow in 36 participants-20 experiencing post-COVID fatigue and 16 healthy controls. SPECT imaging revealed significantly decreased regional cerebral blood flow in the right occipital lobe of fatigued participants compared to the control group. This hypoperfusion was observed even when accounting for factors like age, sex, and cardiovascular risk.
The right occipital lobe is critical for processing visual information, spatial orientation, and attention-functions often impaired in individuals with post-COVID fatigue. This finding aligns with previous research highlighting disruptions in visual processing in post-COVID patients (Renier et al., 2010; de Haas et al., 2021; Friederichs & Friederichs, 2022; Bennett et al., 2020).The study also noted alterations in EEG power spectra during simulated driving tasks in fatigued individuals (Makeig,2009; Chuang et al., 2018), suggesting a broader impact on brain function related to cognitive demands.
Notably, the observed hypoperfusion wasn’t linked to structural brain changes, as evidenced by MRI scans, indicating a functional rather than structural deficit. Researchers propose that the reduced blood flow may contribute to impaired neuronal function and the subjective experience of fatigue. Further inquiry is needed to determine the underlying mechanisms driving this hypoperfusion and to explore potential interventions, such as targeted rehabilitation or pharmacological approaches, to restore cerebral blood flow and alleviate fatigue symptoms. A recent study also indicated structural brain changes in post-COVID fatigue patients (Heine et al., 2023), suggesting a complex interplay between structural and functional alterations.
References
* Bennett CR, Bauer CM, Bailin ES, Merabet LB. Neuroplasticity in cerebral visual impairment (CVI): Assessing functional vision and the neurophysiological correlates of dorsal stream dysfunction. Neurosci Biobehav Rev.2020;108:171-81.
* Chuang C-H,Cao Z,King J-T,wu B-S,Wang Y-K,Lin C-T. brain Electrodynamic and Hemodynamic Signatures Against Fatigue During Driving. Front Neurosci. 2018;12:181.
* de Haas B, Sereno MI, Schwarzkopf DS. Inferior Occipital Gyrus Is Organized along Common gradients of Spatial and Face-Part Selectivity. J neurosci. 2021;41(25):5511-21.
* Friederichs E, Friederichs P.approaching New Clinical Horizons: The Case of Cerebral Visual Impairment (CVI). MRAJ. 2022;10(8).
* Heine J, Schwichtenberg K, hartung TJ, Rekers S, Chien C, Boesl F, et al. Structural brain changes in patients with post-COVID fatigue: a prospective observational study.EClinicalMedicine. 2023;58:101874.
* Makeig S. Tonic Changes in EEG Power spectra during Simulated Driving.Lecture Notes in Computer science. Berlin, Heidelberg: Springer Berlin Heidelberg. 2009. p. 394-403.
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