Brain and cognitive changes in patients with long COVID compared with infection-recovered control subjects

Abstract:

Between 2.5 and 28% of people infected with SARS-CoV-2 suffer Long COVID or persistence of symptoms for months after acute illness. Many symptoms are neurological, but the brain changes underlying the neuropsychological impairments remain unclear. This study aimed to provide a detailed description of the cognitive profile, the pattern of brain alterations in Long COVID and the potential association between them.

To address these objectives, 83 patients with persistent neurological symptoms after COVID-19 were recruited, and 22 now healthy controls chosen because they had suffered COVID-19 but did not experience persistent neurological symptoms. Patients and controls were matched for age, sex and educational level. All participants were assessed by clinical interview, comprehensive standardized neuropsychological tests and structural MRI. The mean global cognitive function of patients with Long COVID assessed by ACE III screening test (Overall Cognitive level – OCLz= -0.39± 0.12) was significantly below the infection recovered-controls (OCLz= +0.32± 0.16, p< 0.01).

We observed that 48% of patients with Long COVID had episodic memory deficit, with 27% also impaired overall cognitive function, especially attention, working memory, processing speed and verbal fluency. The MRI examination included grey matter morphometry and whole brain structural connectivity analysis. Compared to infection recovered controls, patients had thinner cortex in a specific cluster centred on the left posterior superior temporal gyrus.

In addition, lower fractional anisotropy (FA) and higher radial diffusivity (RD) were observed in widespread areas of the patients’ cerebral white matter relative to these controls. Correlations between cognitive status and brain abnormalities revealed a relationship between altered connectivity of white matter regions and impairments of episodic memory, overall cognitive function, attention and verbal fluency.

This study shows that patients with neurological Long COVID suffer brain changes, especially in several white matter areas, and these are associated with impairments of specific cognitive functions.

Source: Serrano Del Pueblo VM, Serrano-Heras G, Romero Sánchez CM, Piqueras Landete P, Rojas-Bartolome L, Feria I, Morris RGM, Strange B, Mansilla F, Zhang L, Castro-Robles B, Arias-Salazar L, López-López S, Payá M, Segura T, Muñoz-López M. Brain and cognitive changes in patients with long COVID compared with infection-recovered control subjects. Brain. 2024 Apr 2:awae101. doi: 10.1093/brain/awae101. Epub ahead of print. PMID: 38562097. https://pubmed.ncbi.nlm.nih.gov/38562097/

Imbalanced Brain Neurochemicals in long COVID and ME/CFS: A Preliminary Study using MRI

Abstract:

Purpose: Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) patients experience multiple complex symptoms, potentially linked to imbalances in brain neurochemicals. This study aims to measure brain neurochemical levels in long COVID and ME/CFS patients as well as healthy controls to investigate associations with severity measures.

Methods: Magnetic resonance spectroscopy (MRS) data was acquired with a 3T Prisma MRI scanner. We measured absolute levels of brain neurochemicals in the posterior cingulate cortex in long COVID (n=17), ME/CFS (n=17), and healthy controls (n=10) using Osprey software. The statistical analyses were performed using SPSS version 29. Age and sex were included as nuisance covariates.

Results: Glutamate levels were significantly higher in long COVID (p=0.02) and ME/CFS (p=0.017) than in healthy controls. No significant difference was found between the two patient cohorts. Additionally, N-acetyl-aspartate levels were significantly higher in long COVID patients (p=0.012). Importantly, brain neurochemical levels were associated with self-reported severity measures in long COVID and ME/CFS.

Conclusion: Our study identified significantly elevated Glutamate and N-acetyl-aspartate levels in long COVID and ME/CFS patients compared with healthy controls. No significant differences in brain neurochemicals were observed between the two patient cohorts, suggesting a potential overlap in their underlying pathology. These findings suggest that imbalanced neurochemicals contribute to the complex symptoms experienced by long COVID and ME/CFS patients.

Source: Thapaliya K, Marshall-Gradisnik S, Eaton-Fitch N, Eftekhari Z, Inderyas M, Barnden L. Imbalanced Brain Neurochemicals in long COVID and ME/CFS: A Preliminary Study using MRI. Am J Med. 2024 Apr 6:S0002-9343(24)00216-X. doi: 10.1016/j.amjmed.2024.04.007. Epub ahead of print. PMID: 38588934. https://www.sciencedirect.com/science/article/pii/S000293432400216X (Full text)

Impaired Hand Grip Strength Correlates with Greater Disability and Symptom Severity in Post-COVID Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Post-COVID syndrome (PCS) encompasses a diverse array of symptoms persisting beyond 3 months after acute SARS-CoV-2 infection, with mental as well as physical fatigue being the most frequent manifestations.
Methods: In 144 female patients with PCS, hand grip strength (HGS) parameters were assessed as an objective measure of muscle fatigue, with 78 meeting the Canadian Consensus Criteria for postinfectious myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The severity of disability and key symptoms was evaluated using self-reported questionnaires.
Results: Patients with ME/CFS exhibited heightened overall symptom severity, including lower physical function (p < 0.001), a greater degree of disability (< 0.001), more severe fatigue (< 0.001), postexertional malaise (p < 0.001), and autonomic dysfunction (p = 0.004) compared to other patients with PCS. While HGS was impaired similarly in all patients with PCS and exhibited a significant correlation with physical function across the entire patient group, HGS of patients with ME/CFS uniquely demonstrated associations with key symptoms.
Conclusions: Thus, impaired HGS serves as an objective marker of physical function in patients with PCS. Only in patients meeting ME/CFS criteria is impaired HGS also associated with the severity of hallmark symptoms. This suggests a common mechanism for muscle fatigue and other symptoms in the ME/CFS subtype, distinct from that in other types of PCS.
Source: Paffrath A, Kim L, Kedor C, Stein E, Rust R, Freitag H, Hoppmann U, Hanitsch LG, Bellmann-Strobl J, Wittke K, et al. Impaired Hand Grip Strength Correlates with Greater Disability and Symptom Severity in Post-COVID Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Journal of Clinical Medicine. 2024; 13(7):2153. https://doi.org/10.3390/jcm13072153 https://www.mdpi.com/2077-0383/13/7/2153

Reduced Cortical Thickness Correlates of Cognitive Dysfunction in Post-COVID-19 Condition: Insights from a Long-Term Follow-up

Abstract:

Background and purpose: There is a paucity of data on long-term neuroimaging findings from individuals who have developed the post-coronavirus 2019 (COVID-19) condition. Only 2 studies have investigated the correlations between cognitive assessment results and structural MR imaging in this population. This study aimed to elucidate the long-term cognitive outcomes of participants with the post-COVID-19 condition and to correlate these cognitive findings with structural MR imaging data in the post-COVID-19 condition.

Materials and methods: A cohort of 53 participants with the post-COVID-19 condition underwent 3T brain MR imaging with T1 and FLAIR sequences obtained a median of 1.8 years after Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) infection. A comprehensive neuropsychological battery was used to assess several cognitive domains in the same individuals. Correlations between cognitive domains and whole-brain voxel-based morphometry were performed. Different ROIs from FreeSurfer were used to perform the same correlations with other neuroimaging features.

Results: According to the Frascati criteria, more than one-half of the participants had deficits in the attentional (55%, n = 29) and executive (59%, n = 31) domains, while 40% (n = 21) had impairment in the memory domain. Only 1 participant (1.89%) showed problems in the visuospatial and visuoconstructive domains. We observed that reduced cortical thickness in the left parahippocampal region (t(48) = 2.28, = .03) and the right caudal-middle-frontal region (t(48) = 2.20, = .03) was positively correlated with the memory domain.

Conclusions: Our findings suggest that cognitive impairment in individuals with the post-COVID-19 condition is associated with long-term alterations in the structure of the brain. These macrostructural changes may provide insight into the nature of cognitive symptoms.

Source: Dacosta-Aguayo R, Puig J, Lamonja-Vicente N, Carmona-Cervelló M, Biaani León-Gómez B, Monté-Rubio G, López-Linfante VM, Zamora-Putin V, Montero-Alia P, Chacon C, Bielsa J, Moreno-Gabriel E, Garcia-Sierra R, Pachón A, Costa A, Mataró M, Prado JG, Martinez-Cáceres E, Mateu L, Massanella M, Violán C, Torán-Monserrat P; Aliança ProHEpiC-19 Cognitiu (The APC Collaborative Group). Reduced Cortical Thickness Correlates of Cognitive Dysfunction in Post-COVID-19 Condition: Insights from a Long-Term Follow-up. AJNR Am J Neuroradiol. 2024 Apr 4. doi: 10.3174/ajnr.A8167. Epub ahead of print. PMID: 38575319. https://pubmed.ncbi.nlm.nih.gov/38575319/

Machine learning algorithms for detection of visuomotor neural control differences in individuals with PASC and ME

Abstract:

The COVID-19 pandemic has affected millions worldwide, giving rise to long-term symptoms known as post-acute sequelae of SARS-CoV-2 (PASC) infection, colloquially referred to as long COVID. With an increasing number of people experiencing these symptoms, early intervention is crucial. In this study, we introduce a novel method to detect the likelihood of PASC or Myalgic Encephalomyelitis (ME) using a wearable four-channel headband that collects Electroencephalogram (EEG) data. The raw EEG signals are processed using Continuous Wavelet Transform (CWT) to form a spectrogram-like matrix, which serves as input for various machine learning and deep learning models. We employ models such as CONVLSTM (Convolutional Long Short-Term Memory), CNN-LSTM, and Bi-LSTM (Bidirectional Long short-term memory). Additionally, we test the dataset on traditional machine learning models for comparative analysis.

Our results show that the best-performing model, CNN-LSTM, achieved an accuracy of 83%. In addition to the original spectrogram data, we generated synthetic spectrograms using Wasserstein Generative Adversarial Networks (WGANs) to augment our dataset. These synthetic spectrograms contributed to the training phase, addressing challenges such as limited data volume and patient privacy. Impressively, the model trained on synthetic data achieved an average accuracy of 93%, significantly outperforming the original model.

These results demonstrate the feasibility and effectiveness of our proposed method in detecting the effects of PASC and ME, paving the way for early identification and management of the condition. The proposed approach holds significant potential for various practical applications, particularly in the clinical domain. It can be utilized for evaluating the current condition of individuals with PASC or ME, and monitoring the recovery process of those with PASC, or the efficacy of any interventions in the PASC and ME populations. By implementing this technique, healthcare professionals can facilitate more effective management of chronic PASC or ME effects, ensuring timely intervention and improving the quality of life for those experiencing these conditions.

Source: Harit Ahuja, Smriti Badhwar, Heather Edgell, Lauren E. Sergio, Marin Litoiu. Machine learning algorithms for detection of visuomotor neural control differences in individuals with PASC and ME. Front. Hum. Neurosci. Sec. Brain-Computer Interfaces, Volume 18 – 2024 | doi: 10.3389/fnhum.2024.1359162 https://www.frontiersin.org/articles/10.3389/fnhum.2024.1359162/full (Full text)

Pituitary–Adrenal Axis and Peripheral Immune Cell Profile in Long COVID

Abstract:

In Long COVID, dysfunction in the pituitary–adrenal axis and alterations in immune cells and inflammatory status are warned against. We performed a prospective study in a cohort of 42 patients who suffered COVID-19 at least 6 months before attending the Long COVID unit at Althaia Hospital.
Based on Post-COVID Functional Status, 29 patients were diagnosed with Long COVID, while 13 were deemed as recovered. The hormones of the pituitary–adrenal axis, adrenocorticotropin stimulation test, and immune cell profiles and inflammatory markers were examined. Patients with Long COVID had significantly lower EuroQol and higher mMRC scores compared to the recovered individuals. Their symptoms included fatigue, myalgia, arthralgia, persistent coughing, a persistent sore throat, dyspnoea, a lack of concentration, and anxiety.
We observed the physiological levels of cortisol and adrenocorticotropin in individuals with or without Long COVID. The results of the adrenocorticotropin stimulation test were similar between both groups. The absolute number of neutrophils was lower in the Long COVID patients compared to recovered individuals (p < 0.05). The total count of B lymphocytes remained consistent, but Long COVID patients had a higher percentage of mature B cells compared to recovered participants (p < 0.05) and exhibited a higher percentage of circulating resident memory CD8+ T cells (p < 0.05) and Treg-expressing exonucleases (p < 0.05).
Our findings did not identify adrenal dysfunction related to Long COVID, nor an association between adrenal function and clinical symptoms. The data indicated a dysregulation in certain immune cells, pointing to immune activation. No overt hyperinflammation was observed in the Long COVID group.
Source: Alijotas-Reig J, Anunciacion-Llunell A, Esteve-Valverde E, Morales-Pérez S, Rivero-Santana S, Trapé J, González-García L, Ruiz D, Marques-Soares J, Miro-Mur F. Pituitary–Adrenal Axis and Peripheral Immune Cell Profile in Long COVID. Biomedicines. 2024; 12(3):581. https://doi.org/10.3390/biomedicines12030581 https://www.mdpi.com/2227-9059/12/3/581 (Full text)

The Effect of Sex on the Risk of Long-COVID and Cardiovascular Complications in Healthy Patients without Comorbidities: Data from a Polish Long-COVID Cardiovascular (PoLoCOV-CVD) Study

Abstract:

Background: The prevalence of long-COVID (LC) presents a significant challenge to healthcare systems globally. There are still some discrepancies on the role of sex as an independent risk factor of LC complications. Thus, we aimed to determine the differences in clinical and cardiovascular complications between males and females without comorbidities after COVID-19.
Methods: Clinical data on the course of the disease with the accompanying symptoms and post-COVID-19 symptoms were compiled from both male and female subjects with a minimum 12-week interval after COVID-19 recovery. Next, the patients were followed for 12 months. ECG, echocardiography, 24 h ECG monitoring, 24 h ambulatory blood pressure monitoring (ABPM), and selected biochemical tests were performed. LC was diagnosed based on the World Health Organization (WHO) definition. To reduce the impact of confounders, i.e., body mass index (BMI) and age, on the results of the study, the nearest neighbour (NN) propensity score matching (PSM) method with a 1:1 ratio was used.
Results: The results were obtained following the removal of cases with comorbidities from the database consisting of 1237 males and 2192 females, and PSM of the new database included 886 cases (443 males and 443 females). At both the 3-month and 1-year post-recovery marks, females consistently reported a higher frequency of LC symptoms compared to males (p < 0.001 for both comparisons). Moreover, after 1 year of follow-up, females exhibited a higher prevalence of LC compared to males, with rates of 14% versus 8.3%, respectively (p = 0.013).
The symptoms that significantly differed between females and males in the 12-month follow-up were hair loss (5.4 vs. 0.7%, p < 0.001), memory and concentration disturbances (8.4 vs. 4.3%, p = 0.013), and headaches (4.3 vs. 1.4%, p = 0.008). Females presented lower mean arterial pressure (MAP) [89 (83–95) mmHg versus (vs.) 94 (89–100); p < 0.001] and lower pulse pressure (PP) [46 (42–52) mmHg vs. 51 (48–57); p < 0.001] in 24 h ABPM and more elevated heart rates (HRs) in 24 h ECG monitoring as well as arrhythmia (p < 0.001 and p = 0.018, respectively). Males had a higher occurrence of ECG abnormalities such as QRS >= 120 ms, ST-T changes, T inversion, arrhythmia, and QRS fragmentation (27.3% vs. 19.2%; p = 0.004). No significant differences were observed between males and females concerning physical activity levels, stress, fatigue, alcohol consumption, and smoking habits.
Conclusions: One year post-COVID-19 recovery, regardless of age and BMI, healthy females more often suffered from LC symptoms than males. They had lower MAP and PP in 24 h ABPM, more often had higher HRs and arrhythmia in 24 h ECG monitoring, and fewer ECG abnormalities than males.
Source: Bielecka-Dabrowa A, Sakowicz A, Gryglewska-Wawrzak K, Kapusta J, Banach M, Jankowski P, Chudzik M. The Effect of Sex on the Risk of Long-COVID and Cardiovascular Complications in Healthy Patients without Comorbidities: Data from a Polish Long-COVID Cardiovascular (PoLoCOV-CVD) Study. Journal of Clinical Medicine. 2024; 13(6):1559. https://doi.org/10.3390/jcm13061559 https://www.mdpi.com/2077-0383/13/6/1559 (Full text)

Brain temperature and free water increases after mild COVID-19 infection

Abstract:

The pathophysiology underlying the post-acute sequelae of COVID-19 remains understudied and poorly understood, particularly in healthy adults with a history of mild infection. Chronic neuroinflammation may underlie these enduring symptoms, but studying neuroinflammatory phenomena in vivo is challenging, especially without a comparable pre-COVID-19 dataset.

In this study, we present a unique dataset of 10 otherwise healthy individuals scanned before and after experiencing mild COVID-19. Two emerging MR-based methods were used to map pre- to post-COVID-19 brain temperature and free water changes. Post-COVID-19 brain temperature and free water increases, which are indirect biomarkers of neuroinflammation, were found in structures functionally associated with olfactory, cognitive, and memory processing.

The largest pre- to post-COVID brain temperature increase was observed in the left olfactory tubercle (p = 0.007, 95% CI [0.48, 3.01]), with a mean increase of 1.75 °C. Notably, the olfactory tubercle is also the region of the primary olfactory cortex where participants with chronic olfactory dysfunction showed the most pronounced increases as compared to those without lingering olfactory dysfunction (adjusted pFDR = 0.0189, 95% CI [1.42, 5.27]). These preliminary insights suggest a potential link between neuroinflammation and chronic cognitive and olfactory dysfunction following mild COVID-19, although further investigations are needed to improve our understanding of what underlies these phenomena.

Source: Sharma AA, Nenert R, Goodman AM, Szaflarski JP. Brain temperature and free water increases after mild COVID-19 infection. Sci Rep. 2024 Mar 28;14(1):7450. doi: 10.1038/s41598-024-57561-6. PMID: 38548815; PMCID: PMC10978935. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10978935/ (Full text)

Use of testosterone replacement therapy to treat long-COVID-related hypogonadism

Abstract:

Summary: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can impair pituitary-gonadal axis and a higher prevalence of hypogonadism in post-coronavirus disease 2019 (COVID-19) patients compared with the general population has been highlighted. Here we report the first case of a patient affected with a long-COVID syndrome leading to hypogonadism and treated with testosterone replacement therapy (TRT) and its effects on clinical and quality of life (QoL) outcomes.

We encountered a 62-year-old man who had been diagnosed with hypogonadotropic hypogonadism about 2 months after recovery from COVID-19 underwent a complete physical examination, general and hormonal blood tests, and self-reported questionnaires administration before and after starting TRT. Following the TRT, both serum testosterone level and hypogonadism-related symptoms were improved, but poor effects occurred on general and neuropsychiatric symptoms and QoL.

Therefore, hypogonadism does not appear to be the cause of neurocognitive symptoms, but rather a part of the long-COVID syndrome; as a consequence, starting TRT can improve the hypogonadism-related symptoms without clear benefits on general clinical condition and QoL, which are probably related to the long-COVID itself. Longer follow-up might clarify whether post-COVID hypogonadism is a transient condition that can revert as the patient recovers from long-COVID syndrome.

Learning points: Hypogonadism is more prevalent in post-COVID-19 patients compared with the general population. In these patients, hypogonadism may be part of long-COVID syndrome, and it is still unclear whether it is a transient condition or a permanent impairment of gonadal function. Testosterone replacement therapy has positive effects on hypogonadism-related clinic without clear benefits on general symptomatology and quality of life, which are more likely related to the long-COVID itself.

Source: Amodeo A, Persani L, Bonomi M, Cangiano B. Use of testosterone replacement therapy to treat long-COVID-related hypogonadism. Endocrinol Diabetes Metab Case Rep. 2024 Mar 22;2024(1):23-0097. doi: 10.1530/EDM-23-0097. PMID: 38520748; PMCID: PMC10959025. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10959025/ (Full text)

Attenuating Post-exertional Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long-COVID: Is Blood Lactate Monitoring the Answer?

Highlights:

  • Lactate monitoring has the potential to extend beyond applied sports settings and could be used to monitor the physiologic and pathophysiological responses to external and internal stimuli in chronic disease areas such as Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Post-Covid syndrome or Long Covid.
  • It is applicable due to the recurrent, episodic and often disabling post-exertional symptom exacerbation (PESE) otherwise referred to as post-exertional malaise (PEM) which is a characteristic symptom of ME/CFS and Long Covid that can last for days and/or weeks.
  • Lactate monitoring presents an opportunity to support those living with ME/CFS and Long COVID, by allowing patients and practitioners to determine the intensity and anaerobic contribution to everyday tasks which could aid the development of pacing strategies that prevent PEM/PESE.

Source: Faghy PMA, Ashton DRE, McNeils MR, Arena R, Duncan DR. Attenuating Post-exertional Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long-COVID: Is Blood Lactate Monitoring the Answer? Curr Probl Cardiol. 2024 Mar 30:102554. doi: 10.1016/j.cpcardiol.2024.102554. Epub ahead of print. PMID: 38561114. https://www.sciencedirect.com/science/article/abs/pii/S0146280624001932