Decreased cerebral blood flow in non-hospitalized adults who self-isolated due to COVID-19

  1. William S.H. Kim
  2. Xiang Ji
  3. Eugenie Roudaia
  4. J. Jean Chen
  5. Asaf Gilboa
  6. Allison Sekuler
  7. Fuqiang Gao
  8. Zhongmin Lin
  9. Aravinthan Jegatheesan
  10. Mario Masellis
  11. Maged Goubran
  12. Jennifer S. Rabin
  13. Benjamin Lam
  14. Ivy Cheng
  15. Robert Fowler
  16. Chris Heyn
  17. Sandra E. Black
  18. Simon J. Graham
  19. Bradley J. MacIntosh

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Abstract

The long-term consequences of coronavirus disease 2019 (COVID-19) on brain physiology and function are not yet well understood. From the recently described NeuroCOVID-19 study, we examined cerebral blood flow (CBF) in 50 participants recruited to one of two groups: 1) adults who previously self-isolated at home due to COVID-19 (n = 39; 116.5 ± 62.2 days since positive diagnosis), or 2) controls who experienced flu-like symptoms but had a negative COVID-19 diagnosis (n = 11). Participants underwent arterial spin labeling magnetic resonance imaging at 3 T to yield measures of CBF. Voxel-wise analyses of CBF were performed to assess for between-group differences, after controlling for age and sex. Relative to controls, the COVID-19 group exhibited decreased CBF in the thalamus, orbitofrontal cortex, and regions of the basal ganglia. Within the COVID-19 group, CBF differences in occipital and parietal regions were observed between those with (n = 11) and without (n = 28) self-reported on-going fatigue. These results suggest long-term changes in brain physiology in adults across the post-COVID-19 timeframe. Moreover, CBF may aid in understanding the heterogeneous symptoms of the post-COVID-19 condition. Future longitudinal studies are needed to further characterize the consequences of COVID-19 on the brain.

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  1. ScreenIT

    SciScore for 10.1101/2022.05.04.22274208: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsIRB: The Research Ethics Board at Sunnybrook Health Sciences Centre approved this study.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    MRI processing: MRI processing was performed using tools from the FMRIB Software Library (FSL, version 6.0.3).
    FMRIB
    suggested: (FSL, RRID:SCR_002823)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    These results need to be interpreted in the context of several limitations. First, although well-matched, the sample sizes of the two groups were modest and unequal; furthermore, a power analysis was not performed. To our knowledge, the current study benefits from the largest ASL dataset focusing on non-hospitalized adults in the post-COVID-19 timeframe. Moreover, recruitment for the NeuroCOVID-19 study is on-going and will address these issues in future studies. Second, our recruitment may be confounded by selection bias. For example, the current study’s cohort was comprised of 66% female and 72% Caucasian participants. We further note that participants needed internet access to be screened for eligibility. Third, our control group exhibited flu-like symptoms of unknown origin. The recruitment of this unique control group is a relatively novel aspect of this study, as these participants are a de-novo sample of adults that experienced non-specific flu-like symptoms during the pandemic. Fourth, ASL images were acquired at a spatial resolution comparable to the average thickness of the cortex, which may be susceptible to partial volume error.45 To address this, we included partial volume correction as an additional ASL processing step in a sensitivity analysis, which did not drastically change the results. Fifth, our fatigue-related exploratory analysis relied on self-reported symptoms. Study staff ensured that on-going fatigue was understood as being impairing to activities of...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2022.05.04.22274208v1 on medRxiv