An experimental study investigating the link between symptom reporting and heart rate variability in chronic fatigue syndrome patients

Abstract:

Our Master’s thesis falls within the research domain of Rehabilitation Sciences and Physiotherapy. In our study we investigated patients with chronic fatigue syndrome (CFS).

CFS is a complicated disorder of which the pathology is still poorly understood. Due to the significant prevalence, the socio-economic impact of the disorder is high. In addition to the physiological dysfunctions that are often reported in CFS literature, patients can also experience altered symptom perception. Patients for example show increased subjective responses to unpleasant somatic stimuli in comparison with healthy persons (Van den Houte et al., 2018). Therefore, this study project fits within the domain of pain, fatigue and somatically unexplained physical symptoms.

Despite a lot of articles reporting the role of altered symptom perception, they mainly focused on symptom perception in the lab. However, these laboratory measurements do not take day-to-day variability in symptoms into account.

We think that the lack of studies investigating the symptomatology in CFS patients via ecological momentary measurements is a gap in the literature. Therefore, in our study, we executed symptom assessments in the lab and in daily life.

In addition, we investigated the interactions between the reported symptoms and heart rate variability (HRV) in order to investigate, on a small scale, if psychological and physiological dysfunctions in patients do not work independently.

Extra information about the pathology of CFS is useful to all professionals in rehabilitation sciences and physical therapy who work with CFS patients. It will help professionals to understand the complex problem of CFS better and to tailor the care for these patients.

Our study is situated in a larger study project with the title “Identifying (psycho)physiology-based subgroups in chronic fatigue syndrome and their relevance for rehabilitation” and with study number S66452. The project is reimbursed by Fonds Wetenschappelijk Onderzoek. The project runs in collaboration with the Multidisciplinary Diagnostic Center of UZ Leuven, the Multidisciplinary Expertise Center Tumi Therapeutics, the Vlaams Instituut voor Biotechnologie KU Leuven Raes Lab and IMEC. All laboratory tasks were conducted in the University Hospital of Leuven.

The study is written in line with the central format. The study topics and research questions were determined in collaboration with Msc. Y. Dooms and Dr. Maaike Van Den Houte. Due to the fact that the study was a component of an ongoing research project, we were not involved in decisions about research design or methodology.

We carried out the academic writing procedure concerning this Master’s thesis. During the writing procedure, we received input from Msc. Y. Dooms. The thesis was written in close cooperation amongst both of us. We both independently contributed to the thesis, reviewed it, and wrote multiple sections together. The data-analysis was done in collaboration with Dr. Maaike Van Den Houte.

Source: Jentro Dest and Daan Grosemans.An experimental study investigating the link between symptom reporting and heart rate variability in chronic fatigue syndrome patients. Master Thesis [University of Hasselt] https://documentserver.uhasselt.be/bitstream/1942/41042/1/1b9fa48e-2513-4665-8ba1-a6b1eb7f2056.pdf (Full text)

The Potential Role of Ocular and Otolaryngological Mucus Proteins in Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating illness associated with a constellation of other symptoms. While the most common symptom is unrelenting fatigue, many individuals also report suffering from rhinitis, dry eyes and a sore throat.

Mucin proteins are responsible for contributing to the formation of mucosal membranes throughout the body. These mucosal pathways contribute to the body’s defense mechanisms involving pathogenic onset. When compromised by pathogens the epithelium releases numerous cytokines and enters a prolonged state of inflammation to eradicate any particular infection.

Based on genetic analysis, and computational theory and modeling we hypothesize that mucin protein dysfunction may contribute to ME/CFS symptoms due to the inability to form adequate mucosal layers throughout the body, especially in the ocular and otolaryngological pathways leading to low grade chronic inflammation and the exacerbation of symptoms.

Source: Kaylin Huitsing, Tara Tritsch, Francisco J. Carrera Arias et al. The Potential Role of Ocular and Otolaryngological Mucus Proteins in Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome, 24 July 2023, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-3171709/v1] https://www.researchsquare.com/article/rs-3171709/v1 (Full text)

 

Characterizing Sjögren-Associated Fatigue: A Distinct Phenotype from ME/CFS

Abstract:

Fatigue is the most commonly reported and debilitating extraglandular symptom of primary Sjögren′s syndrome (pSS). Fatigue and exertional intolerance are hallmark symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We aimed to characterize fatigue and further symptoms among pSS patients and to determine whether there is a symptom overlap in pSS and ME/CFS.
In 19 patients with pSS, we assessed pSS symptom severity and disease activity via questionnaires as well as the Canadian Consensus Criteria (CCC) for ME/CFS. Hand grip strength (HGS) and levels of α1-, α2-, β1-, β2-, M3- and M4-receptor-autoantibodies were measured. A subgroup of pSS patients exhibited severe fatigue and had higher severity of pain (p = 0.045), depression (p = 0.021) and sleep disturbances (p = 0.020) compared to those with less fatigue.
Four of eighteen pSS patients fulfilled the CCC. HGS parameters strongly correlated with fatigue severity (p < 0.05), but strength fully recovered one hour after exertion in contrast to ME/CFS. Levels of β1-, β2- and M4-receptor-autoantibodies were elevated and correlated significantly with disease activity assessed by the ESSDAI (p < 0.05), but not fatigue severity.
Only a minor subgroup of pSS patients fulfills the CCC, and post exertional malaise (PEM) is atypical, as it is primarily triggered by mental/emotional but not physical exertion. HGS assessment is an objective measure to assess overall fatigue severity.
Source: Kim L, Kedor C, Buttgereit F, Heidecke H, Schaumburg D, Scheibenbogen C. Characterizing Sjögren-Associated Fatigue: A Distinct Phenotype from ME/CFS. Journal of Clinical Medicine. 2023; 12(15):4994. https://doi.org/10.3390/jcm12154994 https://www.mdpi.com/2077-0383/12/15/4994 (Full text)

Association analysis between symptomology and herpesvirus IgG antibody concentrations in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis (MS) are two complex and multifactorial diseases whose patients experience persistent fatigue, cognitive impairment, among other shared symptoms. The onset of these diseases has also been linked to acute herpesvirus infections or their reactivations.

In this work, we re-analyzed a previously-described dataset related to IgG antibody responses to 6 herpesviruses (CMV – cytomegalovirus; EBV – Epstein-Barr virus; HHV6 – human herpesvirus-6; HSV1 and HSV2 – herpes simplex virus-1 and -2; VZV – varicella-zoster virus) from the United Kingdom ME/CFS biobank. The primary goal was to report the underlying symptomology and its association with herpesvirus IgG antibodies using data from 4 disease-trigger-based subgroups of ME/CFS patients (n = 222) and patients with MS (n = 46). A secondary objective was to assess whether serological data could distinguish ME/CFS and its subgroup from MS using a SuperLearner (SL) algorithm.

There was evidence for a significant negative association between temporary eye insight disturbance and CMV antibody concentrations and for a significant positive association between bladder problems and EBV antibody concentrations in the MS group.

In the ME/CFS or its subgroups, the most significant antibody-symptom association was obtained for increasing HSV1 antibody concentration and brain fog, a finding in line with a negative impact of HSV1 exposure on cognitive outcomes in both healthy and disease conditions. There was also evidence for a higher number of significant antibody-symptom associations in the MS group than in the ME/CFS group.

When we combined all the serological data in an SL algorithm, we could distinguish three ME/CFS subgroups (unknown disease trigger, non-infection trigger, and an infection disease trigger confirmed in the lab at the time of the event) from the MS group. However, we could not find the same for the remaining ME/CFS group (related to an unconfirmed infection disease).

In conclusion, IgG antibody data explains more the symptomology of MS patients than the one of ME/CFS patients. Given the fluctuating nature of symptoms in ME/CFS patients, the clinical implication of these findings remains to be determined with a longitudinal study. This study is likely to ascertain the robustness of the associations during natural disease course.

Source: Tiago Dias Domingues, João Malato, Anna D. Grabowska, Ji-Sook Lee, Jose Ameijeiras-Alonso, Przemyslaw Biecek, Luís Graça, Helena Mouriño, Carmen Scheibenbogen, Francisco Westermeier, Luis Nacul, Jacqueline M. Cliff, Eliana Lacerda, Nuno Sepúlveda,
Association analysis between symptomology and herpesvirus IgG antibody concentrations in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis. Heliyon, https://doi.org/10.1016/j.heliyon.2023.e18250 https://www.sciencedirect.com/science/article/pii/S2405844023054580 (Full text)

Comparing Frequency and Severity Ratings for ME/CFS versus Controls

Abstract:

Most questionnaires for somatic symptoms focus on occurrence, frequency, or severity, and in doing so, they might not be able to comprehensively assess the burden that symptoms present to patients. For example, a symptom might occur at a high frequency but only a minimal severity, so that it is less likely to be a burden on a patient; whereas a symptom that has both a high frequency and severity is more likely to be negatively impacting a patient.
Study 1 examined frequency and severity scores for classic Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) symptoms among patients with ME/CFS versus a control group. Findings in Study 1 indicate there were more frequency/severity discrepancies for individuals with ME/CFS versus the control group. Study 1 concluded that collecting data on both measures of symptom burden provides unique indicators that can better assess the burden of the symptoms on patients.
In a separate data set, Study 2 reported reliability data on slight differences in the time period and the way the severity was assessed. Study 2 findings indicated high levels of reliability for these changes in the time period and the way questions were asked. These studies provide important psychometric properties that could lead to more reliable and valid assessments of patients with post-viral illnesses.
Source: Jason LA, Benner S, Hansel N. Comparing Frequency and Severity Ratings for ME/CFS versus Controls. Psych. 2023; 5(3):662-669. https://doi.org/10.3390/psych5030042 https://www.mdpi.com/2624-8611/5/3/42 (Full text)

Symptoms and signs of dry eye in US veterans with Myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is clinically defined as persistent and unexplainable post-exertional fatigue and can present with a wide range of cognitive, immunological, endocrinological, and autonomic symptoms. A notable feature of ME/CFS is its comorbidity with pain in multiple compartments. In this study, we examine ocular manifestations associated with ME/CFS, with a focus on ocular surface pain complaints.

Methods: We recruited 124 United States veterans and profiled them for symptoms and signs of dry eye (DE). Individuals were grouped by the presence (n=42) and absence (n=82) of ME/CFS.

Results: The mean age of the population was 55.49 ± 4.61 years, 88.7% of participants identified as male, 58.1% as White, and 39.5% as Hispanic. Demographics, medical comorbidities, and medication use were similar between groups except for depression (57.1% vs. 29.6%, p=0.003), and history of traumatic brain injury (9.5% vs. 1.2%, p=0.03) which were more prevalent in the ME/CFS group. Individuals with ME/CFS reported higher ocular surface pain complaints, both through DE specific questionnaires (Ocular Surface Disease Index, OSDI; 5-Item DE Questionnaire, DEQ-5) and pain specific questionnaires (Neuropathic Pain Symptom Inventory, modified for the Eye, NPSI-E; Numerical rating scale, NRS) (Table 1). Ocular surface parameters were similar between groups, except for persistent pain after topical anesthesia which was more frequent in the ME/CFS group (Table 2).

Conclusions: Individuals who met criteria for ME/CFS had more severe ocular surface pain, but similar signs of DE, compared to controls. This suggests that nerve, and not tear, abnormalities contribute to ocular surface pain in ME/CFS.

Source: Victor Sanchez; Colin Kim; Kimberly Cabrera; Elyana Vittoria Tessa Locatelli; Molly Johnson; Anat Galor. Symptoms and signs of dry eye in US veterans with Myalgic encephalomyelitis/chronic fatigue syndrome. Investigative Ophthalmology & Visual Science June 2023, Vol.64, 3978. https://iovs.arvojournals.org/article.aspx?articleid=2790532 

Serum from Myalgic encephalomyelitis/chronic fatigue syndrome patients causes loss of coherence in cellular circadian rhythms

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disabling disorder characterized by disrupted daily patterns of activity, sleep, and physiology. Past studies in ME/CFS patients have examined circadian rhythms, suggested that desynchronization between central and peripheral rhythms may be an important pathological feature, and identified associated changes in post-inflammatory cytokines such as transforming growth factor beta (TGFB). However, no previous studies have examined circadian rhythms in ME/CFS using cellular models or studied the role of cytokines on circadian rhythms.

In this study, we used serum samples previously collected from ME/CFS patients (n = 20) selected for the presence of insomnia symptoms and matched controls (n = 20) to determine the effects of serum factors and TGFB on circadian rhythms in NIH3T3 mouse immortalized fibroblasts stably transfected with the Per2-luc bioluminescent circadian reporter.

Compared to control serum, ME/CFS serum caused a significant loss of rhythm robustness (decreased goodness of fit) and nominally increased the rate of damping of cellular rhythms. Damping rate was associated with insomnia severity in ME/CFS patients using the Pittsburgh Sleep Quality Index (PSQI). Recombinant TGFB1 peptide applied to cells reduced rhythm amplitude, caused phase delay and decreased robustness of rhythms.

However, there was no difference in TGFB1 levels between ME/CFS and control serum indicating the effects of serum on cellular rhythms cannot be explained by levels of this cytokine. Future studies will be required to identify additional serum factors in ME/CFS patients that alter circadian rhythms in cells.

Source: Heather Wei, Zoe Adelsheim, Rita Fischer, Michael J. McCarthy. Serum from Myalgic encephalomyelitis/chronic fatigue syndrome patients causes loss of coherence in cellular circadian rhythms. Journal of Neuroimmunology. Available online 24 June 2023, 578142. https://doi.org/10.1016/j.jneuroim.2023.578142 https://www.sciencedirect.com/science/article/abs/pii/S0165572823001285

Alcohol intolerance and myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

BACKGROUND: The literature is mixed about the occurrence of alcohol intolerance among patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Surveys that asked respondents with ME/CFS whether they experienced alcohol intolerance within a recent time frame might produce inaccurate results because respondents may indicate that the symptom was not present if they avoid alcohol due to alcohol intolerance.

AIM: To overcome this methodologic problem, participants in the current study were asked whether they have avoided alcohol in the past 6 mo, and if they had, how severe their alcohol intolerance would be if they were to drink alcohol.

METHODS: The instrument used was a validated scale called the DePaul symptom questionnaire. Independent t-tests were performed among the alcohol intolerant or not alcohol intolerant group. The alcohol intolerant group had 208 participants, and the not alcohol intolerant group had 96 participants.

RESULTS: Using specially designed questions to properly identify those with alcohol intolerance, those who experienced alcohol intolerance vs those who did not experience alcohol intolerance experienced more frequent/severe symptoms and domains. In addition, using a multiple regression analysis, the orthostatic intolerance symptom domain was related to alcohol intolerance.

CONCLUSION: The findings from the current study indicated that those with ME/CFS are more likely to experience alcohol intolerance. In addition, those with this symptom have more overall symptoms than those without alcohol intolerance.

Source: Maciuch J, Jason LA. Alcohol intolerance and myalgic encephalomyelitis/chronic fatigue syndrome. World J Neurol 2023; 9(3): 17-27 [DOI: 10.5316/wjn.v9.i3.17] https://www.wjgnet.com/2218-6212/full/v9/i3/17.htm (Full text)

Comparison of a 20 degree and 70 degree tilt test in adolescent myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients

Abstract:

Introduction: During a standard 70-degree head-up tilt test, 90% of adults with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) develop an abnormal reduction in cerebral blood flow (CBF). A 70-degree test might not be tolerated by young ME/CFS patients because of the high incidence of syncopal spells. This study examined whether a test at 20 degrees would be sufficient to provoke important reductions in CBF in young ME/CFS patients.

Methods: We analyzed 83 studies of adolescent ME/CFS patients. We assessed CBF using extracranial Doppler measurements of the internal carotid and vertebral arteries supine and during the tilt. We studied 42 adolescents during a 20 degree and 41 during a 70 degree test.

Results: At 20 degrees, no patients developed postural orthostatic tachycardia (POTS), compared to 32% at 70 degrees (p = 0.0002). The CBF reduction during the 20 degree tilt of -27(6)% was slightly less than during the reduction during a 70 degree test [-31(7)%; p = 0.003]. Seventeen adolescents had CBF measurements at both 20 and 70 degrees. The CBF reduction in these patients with both a 20 and 70 degrees test was significantly larger at 70 degrees than at 20 degrees (p < 0.0001).

Conclusions: A 20 degree tilt in young ME/CFS patients resulted in a CBF reduction comparable to that in adult patients during a 70 degree test. The lower tilt angle provoked less POTS, emphasizing the importance of using the 70 degree angle for that diagnosis. Further study is needed to explore whether CBF measurements during tilt provide an improved standard for classifying orthostatic intolerance.

Source: van Campen CLMC, Rowe PC, Visser FC. Comparison of a 20 degree and 70 degree tilt test in adolescent myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients. Front Pediatr. 2023 May 12;11:1169447. doi: 10.3389/fped.2023.1169447. PMID: 37252045; PMCID: PMC10213432. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10213432/ (Full text)

ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing

Abstract

Introduction: Mechanisms underlying exercise and orthostatic intolerance in myalgic encephalomyelitis/chronic
fatigue syndrome (ME/CFS) have been uncovered by invasive cardiopulmonary exercise testing (iCPET) and
autonomic function testing (AFT), but the relationships between the two are not known. This study aims to determine
if there is overlap of cardiovascular and respiratory pathophysiology in patients who have undergone both
tests.

Methods: Between January 2017 and April 2022, 62 patients were identified with a contemporary iCPET and
AFT. Key variables from the iCPET included peak oxygen uptake (pVO2), cardiac output (pQc), right atrial pressure
(pRAP), and systemic oxygen extraction (Ca-vOy/Hgb) at peak exercise. Key variables from the autonomic testing
included epidermal and sweat gland small fiber neurite density, electrochemical skin conductance, and change in
heart rate (AH) and end tidal carbon dioxide (AETCO2) from supine to upright during the tilt table test
(TTT).

Results: All 62 patients demonstrated preload failure (pRAP < 6.5mmHg). Of this group, 54 patients (87.1%) fulfilled NAM criteria for ME/CFS, with 32 testing positive (59.3%) for small fiber neuropathy (SFN) using either morphological and/or functional testing. Significant correlations were found between pVOg and both AH (r=-0.439. P<0.05) and AETCO, (r=0.474, P<0.05) during TTT. The same tilt table variables were found to be significantly correlated with pQc (r=-0.365, P<0.05 and r=0.351, P<0.05) from the iCPET. It should be noted that 8 of the ME/CFS SFN patients (25%) fulfilled diagnostic criteria for postural orthostatic tachycardia syndrome (POTS) based on the tilt table test.

Conclusion: Decreased oxygen uptake and cardiac output at peak exercise during iCPET correlated with a greater change in heart rate and ETCO from supine to upright during TTT. There appears to be significant overlap of cardiopulmonary pathophysiology in ME/CFS underlying exercise and orthostatic symptoms.

Source: J. Squires, K. Wichmann Madsen, M.C. Stovall, S. Al-Zayer, W. Xiao, C.-J. Chang, P. Novak, D.M. Systrom. ME/CFS Pathophysiology Investigated by Invasive Cardiopulmonary Exercise Testing and Autonomic Function Testing. American Journal of Respiratory and Critical Care Medicine 2023;207:A2996. https://www.atsjournals.org/doi/abs/10.1164/ajrccm-conference.2023.207.1_MeetingAbstracts.A2996