Tag: brain volume

Evidence of clinical and brain recovery in post-COVID-19 condition: a three-year follow-up study

Abstract:

Fatigue and cognitive dysfunction linked to persistent brain changes have been reported for up to two years after COVID-19. In this study, we followed the clinical, neuroimaging and fluid biomarker trajectories over three years post SARS-CoV-2 infection to evaluate potential signs and underlying factors of brain recovery.

We conducted a monocentric, longitudinal study using resting-state functional and structural T1-weighted magnetic resonance imaging data from 51 patients with Post-COVID-19 Condition (mean age 50 years, 33 female) collected at a mean time of 6, 23 and 38 months after COVID-19 infection. The trajectory of brain changes was compared to 23 age- and sex-matched healthy controls (mean age 37 years, 13 female) with similar time intervals between brain scans and analysed in relation to clinical, neuropsychological and fluid biomarkers including interleukins and neurodestruction markers at all timepoints. In addition, hand grip strength to evaluate muscular fatigue, was assessed at the final follow-up visit.

Self-reported fatigue improved over time but was still moderate on average three years after COVID-19 infection, while measures of hand grip strength and cognitive performance were largely unaffected. We found a significant increase of both lateral ventricles (∼8%) and the third (∼6%) ventricle accompanied by a structural volume reduction in adjacent areas including the thalamus, pallidum, caudate nucleus and putamen. An increased neuronal activation pattern was widespread and pronounced in these areas. The brainstem no longer exhibited volume loss as reported in our pervious study, but enhanced functional connectivity. Laboratory markers including interleukins and neuronal injury markers remained within the normal reference ranges across all study timepoints.

Our study revealed an overall slow but evident clinical improvement, including improved fatigue, regular muscular strength and recovery as well as normal cognitive function without signs of systemic inflammation three years after COVID-19. Clinical improvement is reflected by a pattern of brain recovery along periventricular regions. This pattern is characterized by structural stabilization and increased connectivity starting in the brainstem as well as efficient neuronal recruitment and increased activation in the basal ganglia, with no evidence of neuronal injury. These results highlight the positive long-term recovery trajectory in post-COVID patients.

Source: Ravi Dadsena, Sophie Wetz, Anna Hofmann, Ana Sofia Costa, Sandro Romanzetti, Stella Andrea Lischewski, Christina Krockauer, Carolin Balloff, Ferdinand Binkofski, Jörg B Schulz, Kathrin Reetz, Julia Walders, Evidence of clinical and brain recovery in post-COVID-19 condition: a three-year follow-up study, Brain Communications, 2025;, fcaf366, https://doi.org/10.1093/braincomms/fcaf366 https://academic.oup.com/braincomms/advance-article/doi/10.1093/braincomms/fcaf366/8262587 (Full study available as PDF file)

Brainstem Reduction and Deformation in the 4th Ventricle Cerebellar Peduncles in Long COVID Patients: Insights into Neuroinflammatory Sequelae and “Broken Bridge Syndrome”

Abstract:

Post-COVID Syndrome (PCS), also known as Long COVID, is characterized by persistent and often debilitating neurological sequelae, including fatigue, cognitive dysfunction, motor deficits, and autonomic dysregulation (Dani et al., 2021). This study investigates structural and functional alterations in the brainstem and cerebellar peduncles of individuals with PCS using diffusion tensor imaging (DTI) and volumetric analysis. Forty-four PCS patients (15 bedridden) and 14 healthy controls underwent neuroimaging. Volumetric analysis focused on 22 brainstem regions, including the superior cerebellar peduncle (SCP), middle cerebellar peduncle (MCP), periaqueductal gray (PAG), and midbrain reticular formation (mRt).

Significant volume reductions were observed in the SCP (p < .001, Hedges’ g = 3.31) and MCP (p < .001, Hedges’ g = 1.77), alongside decreased fractional anisotropy (FA) in the MCP, indicative of impaired white matter integrity. FA_Avg fractional anisotropy average tested by FreeSurfer Tracula, is an index of white matter integrity, reflecting axonal fiber density, axonal diameter and myelination. These neuroimaging findings correlated with clinical manifestations of motor incoordination, proprioceptive deficits, and autonomic instability. Furthermore, volume loss in the dorsal raphe (DR) and midbrain reticular formation suggests disruption of pain modulation and sleep-wake cycles, consistent with patient-reported symptoms.

Post-mortem studies provide supporting evidence for brainstem involvement in COVID-19. Radtke et al. (2024) reported activation of intracellular signaling pathways and release of immune mediators in brainstem regions of deceased COVID-19 patients, suggesting an attempt to inhibit viral spread. While viral genetic material was detectable, infected neurons were not observed. Matschke et al. (2020) found that microglial activation and cytotoxic T lymphocyte infiltration were predominantly localized to the brainstem and cerebellum, with limited involvement of the frontal lobe. This aligns with clinical observations implicating the brainstem in PCS pathophysiology. Cell-specific expression analysis of genes contributing to viral entry (ACE2, TMPRSS2, TPCN2, TMPRSS4, NRP1, CTSL) in the cerebral cortex showed their presence in neurons, glial cells, and endothelial cells, indicating the potential for SARS-CoV-2 infection of these cell types. Associations with autoimmune diseases with specific autoantibodies, including beta-2 and M-2 against G-protein coupled alpha-1, beta-1, beta-2 adrenoceptors against angiotensin II type 1 receptor or M1,2,3-mAChR, among others, voltage-gated calcium channels (VGCC) are known (Blitshteyn et al. 2015 and Wallukat and Schminke et al. 2014).

These findings support the “Broken Bridge Syndrome” hypothesis, positing that structural disconnections between the brainstem and cerebellum contribute to PCS symptomatology. Furthermore, we propose that chronic activation of the Extended Autonomic System (EAS), encompassing the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system, may perpetuate these symptoms (Goldstein, 2020). Perturbations in this system may relate to the elevation of toxic autoantibodies AABs (Beta-2 and M-2), specific epitopes of the COVID virus’s SPIKE protein and Cytokine storm of IL-1, IL-6, and IL-8 in their increased numbers (1,000->10,000)

Further research is warranted to elucidate the underlying neuroinflammatory mechanisms, EAS dysregulation, and potential therapeutic interventions for PCS

Source: Ziaja Peter Christof, Young Yvette Susanne, Stark Sadre-Chirazi Michael, Lindner Thomas, Zurék Grzegorz, Sedlacik Jan. Brainstem Reduction and Deformation in the 4th Ventricle Cerebellar Peduncles in Long COVID Patients: Insights into Neuroinflammatory Sequelae and “Broken Bridge Syndrome” medRxiv 2025.04.08.25325108; doi: https://doi.org/10.1101/2025.04.08.25325108 https://www.medrxiv.org/content/10.1101/2025.04.08.25325108v1.full-text (Full text)

Hippocampal subfield volume alterations and associations with severity measures in long COVID and ME/CFS: A 7T MRI study

Abstract:

Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) patients share similar symptoms including post-exertional malaise, neurocognitive impairment, and memory loss. The neurocognitive impairment in both conditions might be linked to alterations in the hippocampal subfields. Therefore, this study compared alterations in hippocampal subfields of 17 long COVID, 29 ME/CFS patients, and 15 healthy controls (HC).

Structural MRI data was acquired with sub-millimeter isotropic resolution on a 7 Telsa MRI scanner and hippocampal subfield volumes were then estimated for each participant using FreeSurfer software. Our study found significantly larger volumes in the left hippocampal subfields of both long COVID and ME/CFS patients compared to HC.

These included the left subiculum head (long COVID; p = 0.01, ME/CFS; p = 0.002,), presubiculum head (long COVID; p = 0.004, ME/CFS; p = 0.005), molecular layer hippocampus head (long COVID; p = 0.014, ME/CFS; p = 0.011), and whole hippocampal head (long COVID; p = 0.01, ME/CFS; p = 0.01). Notably, hippocampal subfield volumes were similar between long COVID and ME/CFS patients.

Additionally, we found significant associations between hippocampal subfield volumes and severity measures of ‘Pain’, ‘Duration of illness’, ‘Severity of fatigue’, ‘Impaired concentration’, ‘Unrefreshing sleep’, and ‘Physical function’ in both conditions. These findings suggest that hippocampal alterations may contribute to the neurocognitive impairment experienced by long COVID and ME/CFS patients. Furthermore, our study highlights similarities between these two conditions.

Source: Thapaliya K, Marshall-Gradisnik S, Eaton-Fitch N, Barth M, Inderyas M, Barnden L. Hippocampal subfield volume alterations and associations with severity measures in long COVID and ME/CFS: A 7T MRI study. PLoS One. 2025 Jan 13;20(1):e0316625. doi: 10.1371/journal.pone.0316625. PMID: 39804864; PMCID: PMC11729965. https://pmc.ncbi.nlm.nih.gov/articles/PMC11729965/ (Full text)

Cognitive impact and brain structural changes in long COVID patients: a cross-sectional MRI study two years post infection in a cohort from Argentina

Abstract:

Objective: Long COVID is a condition characterised by persistent symptoms after a SARS-CoV-2 infection, with neurological manifestations being particularly frequent. Existing research suggests that long COVID patients not only report cognitive symptoms but also exhibit measurable cognitive impairment. Neuroimaging studies have identified structural alterations in brain regions linked to cognitive functions. However, most of these studies have focused on patients within months of their initial infection. This study aims to explore the longer-term cognitive effects and brain structural changes in long COVID patients, approximately two years post-infection, in a cohort from San Martín, Buenos Aires, Argentina.

Methods: We conducted a cross-sectional study involving 137 participants: 109 with long COVID symptoms and 28 healthy controls. The participants underwent an initial clinical assessment, completed a structured questionnaire and standardised scales, underwent a cognitive assessment, and had a brain MRI scan. Structural MRI images were processed via FreeSurfer and FSL to obtain volumetric measures for subcortical and cortical regions, along with regional cortical thickness. Differences between groups for these variables were analysed using ANCOVA, with permutation tests applied to correct for multiple comparisons.

Results: Long COVID patients reported persistent cognitive symptoms such as memory problems and brain fog, with higher levels of fatigue and reduced quality of life compared to controls. Despite subjective cognitive complaints, cognitive tests did not reveal significant differences between groups, except for the TMT-A (p = 0.05). MRI analysis revealed decreased volume in the cerebellum (p = 0.03), lingual gyrus (p = 0.04), and inferior parietal regions (p = 0.03), and reduced cortical thickness in several areas, including the left and right postcentral gyri (p = 0.02, p = 0.03) and precuneus (p = 0.01, p = 0.02).

Conclusions: This study highlights the enduring impact of long COVID on quality of life and physical activity, with specific brain structural changes identified two years post-infection. Although cognitive tests did not show clear impairment, the observed brain atrophy and significant reduction in quality of life emphasize the need for comprehensive interventions and further longitudinal studies to understand the long-term effects of long COVID on cognition and brain health.

Source: Cataldo SA, Micciulli A, Margulis L, Cibeyra M, Defeo S, Horovitz SG, Martino A, Melano R, Mena M, Parisi F, Santoro D, Sarmiento F, Belzunce MA. Cognitive impact and brain structural changes in long COVID patients: a cross-sectional MRI study two years post infection in a cohort from Argentina. BMC Neurol. 2024 Nov 18;24(1):450. doi: 10.1186/s12883-024-03959-8. PMID: 39558250; PMCID: PMC11572126. https://pmc.ncbi.nlm.nih.gov/articles/PMC11572126/ (Full text)

Cerebral microstructural alterations in Post-COVID-condition are related to cognitive impairment, olfactory dysfunction and fatigue

Abstract:

After contracting COVID-19, a substantial number of individuals develop a Post-COVID-Condition, marked by neurologic symptoms such as cognitive deficits, olfactory dysfunction, and fatigue. Despite this, biomarkers and pathophysiological understandings of this condition remain limited. Employing magnetic resonance imaging, we conduct a comparative analysis of cerebral microstructure among patients with Post-COVID-Condition, healthy controls, and individuals that contracted COVID-19 without long-term symptoms.

We reveal widespread alterations in cerebral microstructure, attributed to a shift in volume from neuronal compartments to free fluid, associated with the severity of the initial infection. Correlating these alterations with cognition, olfaction, and fatigue unveils distinct affected networks, which are in close anatomical-functional relationship with the respective symptoms.

Source: Hosp JA, Reisert M, Dressing A, Götz V, Kellner E, Mast H, Arndt S, Waller CF, Wagner D, Rieg S, Urbach H, Weiller C, Schröter N, Rau A. Cerebral microstructural alterations in Post-COVID-condition are related to cognitive impairment, olfactory dysfunction and fatigue. Nat Commun. 2024 May 18;15(1):4256. doi: 10.1038/s41467-024-48651-0. PMID: 38762609; PMCID: PMC11102465. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11102465/ (Full text)

Hypothalamus volumes in adolescent Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Impact of self-reported fatigue and illness duration

Abstract:

Adolescent Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex illness of unknown aetiology. Emerging theories suggest ME/CFS may reflect a progressive, aberrant state of homeostasis caused by disturbances within the hypothalamus, yet few studies have investigated this using magnetic resonance imaging in adolescents with ME/CFS.

We conducted a volumetric analysis to investigate whether whole and regional hypothalamus volumes in adolescents with ME/CFS differed compared to healthy controls, and whether these volumes were associated with fatigue severity and illness duration. 48 adolescents (25 ME/CFS, 23 controls) were recruited. Lateralised whole and regional hypothalamus volumes, including the anterior superior, superior tubular, posterior, anterior inferior and inferior tubular subregions, were calculated from T1 weighted images.

When controlling for age, sex and intracranial volume, Bayesian linear regression revealed no evidence for differences in hypothalamus volumes between groups. However, in the ME/CFS group, a negative linear relationship between right anterior superior volumes and fatigue severity was identified, which was absent in controls. In addition, Bayesian ordinal regression revealed a likely-positive association between illness duration and right superior tubular volumes in the ME/CFS group.

While these findings suggest overall comparability in regional and whole hypothalamus volumes between adolescents with ME/CFS and controls, preliminary evidence was identified to suggest greater fatigue and longer illness duration were associated with greater right anterior superior and superior tubular volumes, respectively. These regions contain the anterior and superior divisions of the paraventricular nucleus, involved in the neuroendocrine response to stress, suggesting involvement in ME/CFS pathophysiology. However, replication in a larger, longitudinal cohort is required.

Source: Hollie Byrne, Elisha K Josev, Sarah J Knight, Adam Scheinberg, Katherine Rowe, Lionel Lubitz, Marc L Seal. Hypothalamus volumes in adolescent Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Impact of self-reported fatigue and illness duration. medRxiv 2023.05.16.23290031; doi: https://doi.org/10.1101/2023.05.16.23290031 (Full text available as PDF file)

Effect of Post-COVID-19 on Brain Volume and Glucose Metabolism: Influence of Time Since Infection and Fatigue Status

Abstract:

Post-COVID-19 syndrome (PCS) fatigue is typically most severe <6 months post-infection. Combining magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging with the glucose analog [18F]-Fluorodeoxyglucose (FDG) provides a comprehensive overview of the effects of PCS on regional brain volumes and metabolism, respectively. The primary purpose of this exploratory study was to investigate differences in MRI/PET outcomes between people < 6 months (N = 18, 11 female) and > 6 months (N = 15, 6 female) after COVID-19.
The secondary purpose was to assess if any differences in MRI/PET outcomes were associated with fatigue symptoms. Subjects > 6 months showed smaller volumes in the putamen, pallidum, and thalamus compared to subjects < 6 months. In subjects > 6 months, fatigued subjects had smaller volumes in frontal areas compared to non-fatigued subjects. Moreover, worse fatigue was associated with smaller volumes in several frontal areas in subjects > 6 months.
The results revealed no brain metabolism differences between subjects > 6 and < 6 months. However, both groups exhibited both regional hypo- and hypermetabolism compared to a normative database. These results suggest that PCS may alter regional brain volumes but not metabolism in people > 6 months, particularly those experiencing fatigue symptoms.
Source: Deters JR, Fietsam AC, Gander PE, Boles Ponto LL, Rudroff T. Effect of Post-COVID-19 on Brain Volume and Glucose Metabolism: Influence of Time Since Infection and Fatigue Status. Brain Sciences. 2023; 13(4):675. https://doi.org/10.3390/brainsci13040675 https://www.mdpi.com/2076-3425/13/4/675 (Full text)

Neuropathology and Neurological Manifestations in ME/CFS and Long COVID with focus on Post-Exertional Symptom Exacerbation: a Literature Review

Summary:

Many of the people that get infected with the Coronavirus develop long-lasting complaints and are diagnosed with Long COVID after the acute infection is gone. These complains can last several months or years and include fatigue, cognitive impairment, sleeping problems and post-exertional symptom exacerbation (PESE). Research shows that COVID-19 patients with an acute infection have abnormalities in their brain, which could potentially lead to long-lasting neurological problems and symptoms. However, although many researchers are trying to uncover the underlying mechanisms, Long COVID is still very new.
The underlying mechanisms causing and maintaining the disease are therefore unclear. A large group of Long COVID patients resembles patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in terms of symptoms and, in many cases, the viral trigger of the disease. A core symptom of ME/CFS is PESE, which is uncommon in other fatiguing illnesses, but frequently seen in Long COVID patients. PESE involves an abnormal worsening of symptoms and cognitive and physical functions after any type of normal activity. Because of the large symptom overlap and lack of knowledge regarding PESE, underlying brain-mechanisms associated with Long COVID and ME/CFS in general as well as after physical exertion were investigated.
The findings of this review indicate that ME/CFS is associated with several abnormalities in the brain which are also proposed to be present in Long COVID patients. Such abnormalities include inflammation of the brain, shrinkage of the brain and less blood flow to the brain. After physical exertion, these abnormalities might be exacerbated in ME/CFS patients. This results in a brain that needs to work harder than the healthy brain to complete a task. It is demonstrated by increased brain activity in several brain regions after physical exertion and general symptom exacerbation. Since the two diseases seem to have a large overlap in symptoms and underlying brain-mechanisms, this finding might apply to patients with long COVID as well. Importantly, Long COVID seems to consist of different subgroups of which a large part fulfills the criteria for ME/CFS.
Treatment and therapy for ME/CFS patients is therefore likely transferable to this subgroup of Long COVID patients, with explicit attention towards the PESE phenomenon. More research is needed to uncover the underlying mechanisms as well as correct treatment approach of these diseases. Future research should take subgroups of Long COVID into account.
Source: Rodenburg, Sanne. Neuropathology and Neurological Manifestations in ME/CFS and Long COVID with focus on Post-Exertional Symptom Exacerbation: a Literature Review. Master Thesis, Utrecht University. March 14, 2023. https://studenttheses.uu.nl/bitstream/handle/20.500.12932/43647/Rodenburg_7433050_Neuropathology%20and%20neurological%20manifestations%20in%20MECFS%20and%20Long%20COVID%20with%20focus%20on%20PESE.pdf (Full text)

Brainstem volume changes in myalgic encephalomyelitis/chronic fatigue syndrome and long COVID patients

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID patients have overlapping neurological, autonomic, pain, and post-exertional symptoms. We compared volumes of brainstem regions for 10 ME/CFS (CCC or ICC criteria), 8 long COVID (WHO Delphi consensus), and 10 healthy control (HC) subjects on 3D, T1-weighted MRI images acquired using sub-millimeter isotropic resolution using an ultra-high field strength of 7 Tesla.

Group comparisons with HC detected significantly larger volumes in ME/CFS for pons (p = 0.004) and whole brainstem (p = 0.01), and in long COVID for pons (p = 0.003), superior cerebellar peduncle (p = 0.009), and whole brainstem (p = 0.005). No significant differences were found between ME/CFS and long COVID volumes. In ME/CFS, we detected positive correlations between the pons and whole brainstem volumes with “pain” and negative correlations between the midbrain and whole brainstem volumes with “breathing difficulty.”

In long COVID patients a strong negative relationship was detected between midbrain volume and “breathing difficulty.” Our study demonstrated an abnormal brainstem volume in both ME/CFS and long COVID consistent with the overlapping symptoms.

Source: Thapaliya K, Marshall-Gradisnik S, Barth M, Eaton-Fitch N, Barnden L. Brainstem volume changes in myalgic encephalomyelitis/chronic fatigue syndrome and long COVID patients. Frontiers in Neuroscience, 2023 March 2; 17:1125208. https://www.frontiersin.org/articles/10.3389/fnins.2023.1125208/full (Full text)