Category: Symptoms

Mixed methods system for the assessment of post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome: an exploratory study

Abstract:

Background A central feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is post-exertional malaise (PEM), which is an acute worsening of symptoms after a physical, emotional and/or mental exertion. Dynamic measures of PEM have historically included scaled questionnaires, which have not been validated in ME/CFS. To enhance our understanding of PEM and how best to measure it, we conducted semistructured qualitative interviews (QIs) at the same intervals as visual analogue scale (VAS) measures after a cardiopulmonary exercise test (CPET).

Methods Ten ME/CFS and nine healthy volunteers participated in a CPET. For each volunteer, PEM symptom VAS (12 symptoms) and semistructured QIs were administered at six timepoints over 72 hours before and after a single CPET. QI data were used to plot the severity of PEM at each time point and identify the self-described most bothersome symptom for each ME/CFS volunteer. Performance of QI and VAS data was compared with each other using Spearman correlations.

Results Each ME/CFS volunteer had a unique PEM experience, with differences noted in the onset, severity, trajectory over time and most bothersome symptom. No healthy volunteers experienced PEM. QI and VAS fatigue data corresponded well an hour prior to exercise (pre-CPET, r=0.7) but poorly at peak PEM (r=0.28) and with the change from pre-CPET to peak (r=0.20). When the most bothersome symptom identified from QIs was used, these correlations improved (r=0.0.77, 0.42. and 0.54, respectively) and reduced the observed VAS scale ceiling effects.

Conclusion In this exploratory study, QIs were able to capture changes in PEM severity and symptom quality over time, even when VAS scales failed to do so. Measurement of PEM can be improved by using a quantitative–qualitative mixed model approach.

Source: Stussman B, Calco B, Norato G, et al. Mixed methods system for the assessment of post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome: an exploratory study. BMJ Neurology Open 2024;6:e000529. doi: 10.1136/bmjno-2023-000529  https://neurologyopen.bmj.com/content/6/1/e000529 (Full text)

Immune cell exhaustion, dysfunction, and metabolism in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract;
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic and incapacitating multisystem condition with unknown etiology, no cure, and no FDA- approved treatments, all of which can be attributed to historical underfunding, widespread misinformation, and the complexity of the disease. Many patients encounter several immune-related symptoms, extreme fatigue, post-exertional malaise, and a flu-like onset. Studies have documented changes in ME/CFS immune cell populations and decreased natural killer (NK) cell performance, along with aberrant cytokine production, reduced glycolysis in T cells, and altered metabolites relevant to fatty acid oxidation, implicating potential intracellular metabolic dysregulation.
This knowledge prompted me to investigate fatty acid oxidation and immune cell functional states in isolated ME/CFS lymphocytes. Using extracellular flux analysis and flow cytometry, I observed elevated fatty acid oxidation levels in ME/CFS immune cells, including NK cells, CD4+ memory cells, CD4+ effector cells, CD8+ naïve cells, and CD8+ memory cells compared to healthy controls, particularly during high energy demands and activation. My findings suggest a metabolic dysfunction in ME/CFS immune cells, consistent with T cell exhaustion – a state that hinders immune cell proliferation, survival, and cytokine production following persistent antigen stimulation.
Building upon these results, I further investigated immune cell exhaustion and dysfunction in isolated CD8+ and CD4+ T cells from ME/CFS and healthy samples. I analyzed T cell sub-populations, including naïve, effector, memory, regulatory, and helper T cells, for frequencies of inhibitory receptors and transcription factors associated with dysfunctional immune cell states.
I detected distinct transcription factor dynamics and elevated exhausted T cell phenotype proportions in ME/CFS CD8+ T cell populations compared to healthy controls. In ME/CFS CD4+ T cells, I also observed altered inhibitory receptor population frequencies compared to healthy control samples. Moreover, dysfunctional T cell features correlated with ME/CFS health status and symptom presentation.
Overall, my findings detect dysfunctional T cell states in specific ME/CFS cell populations, which can lead to reduced effector function that may contribute to ME/CFS symptom presentation. This work highlights the significance of assessing both metabolic components and immune cell dysfunction-associated targets in the development of potential therapeutic interventions for individuals with ME/CFS.
Source: Maya, Jessica. Immune cell exhaustion, dysfunction, and metabolism in myalgic encephalomyelitis/chronic fatigue syndrome. Cornell Theses and Dissertations. 2024. https://ecommons.cornell.edu/items/242f8723-6f87-47cc-b36d-bf51a21f4255

Mismatch between subjective and objective dysautonomia

Abstract:

Autonomic symptom questionnaires are frequently used to assess dysautonomia. It is unknown whether subjective dysautonomia obtained from autonomic questionnaires correlates with objective dysautonomia measured by quantitative autonomic testing. The objective of our study was to determine correlations between subjective and objective measures of dysautonomia.

This was a retrospective cross-sectional study conducted at Brigham and Women’s Faulkner Hospital Autonomic Laboratory between 2017 and 2023 evaluating the patients who completed autonomic testing. Analyses included validated autonomic questionnaires [Survey of Autonomic Symptoms (SAS), Composite Autonomic Symptom Score 31 (Compass-31)] and standardized autonomic tests (Valsalva maneuver, deep breathing, sudomotor, and tilt test). The autonomic testing results were graded by a Quantitative scale for grading of cardiovascular reflexes, sudomotor tests and skin biopsies (QASAT), and Composite Autonomic Severity Score (CASS). Autonomic testing, QASAT, CASS, and SAS were obtained in 2627 patients, and Compass-31 in 564 patients.

The correlation was strong between subjective instruments (SAS vs. Compass-31, r = 0.74, p < 0.001) and between objective instruments (QASAT vs. CASS, r = 0.81, p < 0.001). There were no correlations between SAS and QASAT nor between Compass-31 and CASS. There continued to be no correlations between subjective and objective instruments for selected diagnoses (post-acute sequelae of COVID-19, n = 61; postural tachycardia syndrome, 211; peripheral autonomic neuropathy, 463; myalgic encephalomyelitis/chronic fatigue syndrome, 95; preload failure, 120; post-treatment Lyme disease syndrome, 163; hypermobile Ehlers-Danlos syndrome, 213; neurogenic orthostatic hypotension, 86; diabetes type II, 71, mast cell activation syndrome, 172; hereditary alpha tryptasemia, 45).

The lack of correlation between subjective and objective instruments highlights the limitations of the commonly used questionnaires with some patients overestimating and some underestimating true autonomic deficit. The diagnosis-independent subjective–objective mismatch further signifies the unmet need for reliable screening surveys. Patients who overestimate the symptom burden may represent a population with idiosyncratic autonomic-like symptomatology, which needs further study. At this time, the use of autonomic questionnaires as a replacement of autonomic testing cannot be recommended.

Source: Novak, P., Systrom, D., Marciano, S.P. et al. Mismatch between subjective and objective dysautonomia. Sci Rep 14, 2513 (2024). https://doi.org/10.1038/s41598-024-52368-x https://www.nature.com/articles/s41598-024-52368-x (Full text)

Sleep Issues Amongst People With ME – A Conversation with Professor Dorothy Bruck

by Bronc

Just before Xmas 2010 I was overcome by a bout of Swine Flu. After the holiday, which was a complete blur due to sickness, I went back to work in January feeling very weak. Over the course of the next 8 months, up until my diagnosis of ME, I was afflicted by a bewildering variety of symptoms which caused a great deal of physical and mental suffering. The symptoms which affected me the most in some respects were the unrefreshing sleep and acute insomnia which made me fear that I would lose my job. I was working over 50 hours a week in a very stressful and physically demanding job which I increasingly struggled to keep onto partly due to the lack of sleep/unrefreshing sleep. I noticed a considerable decline in my ability to do some of the basics of my job as I struggled to concentrate and felt increasingly unable to keep up with the very demanding target driven regime at work. Trying to teach a class of 30 teenagers can be hard work at the best of times but when you’re getting 4 hours of unrefreshing sleep it can be a nightmare. Once I received my diagnosis of ME one of the first things I asked my GP for was a course of sleeping tablets to help me overcome the worst of the insomnia.

Since my diagnosis unrefreshing sleep and insomnia have been my constant companions. Sadly, none of the health professionals and scientists I’ve spoken to over the years have been able to offer much insight as to what is causing this and what might help treat it.

There is lack of research into this important aspect of ME. As we all know sleep is the foundation stone of good health for anyone. Those of us who live with dysfunctional sleep all the time it can be very debilitating and have a considerable knock on effect on the other symptoms of our illness.

I recently spoke with Professor Dorothy Bruck about her insights into some of the sleep issues which affect people with ME.

Emeritus Professor Bruck’s main area of research interest and expertise is sleep and sleep health. She has been thinking about, and working with, many aspects of sleep for about 40 years. Professor Bruck has had a long academic career at Victoria University in Melbourne, with particular expertise in sleep/wake behaviour, mental health, chronic fatigue syndrome, waking thresholds and human behaviour in emergencies. She has an international research reputation, with over 120 peer-reviewed full-length publications, $2.5 million in competitive grant income, dozens of invited international and national professional speaking engagements, and numerous awards. Professor Bruck’s research has been regularly featured in the media, including Time Magazine and New Scientist. Apart from her academic work Professor Bruck has worked as a sleep psychologist and most recently she was Chair of the Sleep Health Foundation (Australia). She is now semi-retired and lives in the Far South of Tasmania, Australia.

Q1. How did you get involved in the field of M.E. research?

I have been a sleep researcher since undertaking my Honours degree in 1978, with a particular interest in disorders of excessive daytime sleepiness such as narcolepsy.  In 2010 my teenage son was diagnosed with ME/CFS, which left him bed and recliner bound for about 10 of the next 15 years. Remarkably he has now improved sufficiently to hold a job with flexible hours.  While he was very sick I met ME/CFS clinicians and researchers in Melbourne and we managed to obtain funding for a series of studies focussing on sleep and gut microbes.  We have since published this research with Melinda Jackson and Amy Wallis as the first authors.

Q2. In October 2021 the National Institute for Clinical Excellence in the UK issued a new guideline for the treatment and care of people with M.E. This guideline recognised that for a diagnosis of M.E. to be made people had to suffer from four key symptoms. Unrefreshing sleep or non-restorative sleep is recognised as one of the core symptoms of the illness. The sleep disturbance experienced by pwME can be broken down into two categories: disturbed sleep patterns and unrefreshing sleep. Despite this, there is remarkably little research being conducted into this core symptom of the illness. Amongst the limited studies that have been done into this issue there appears to be no consensus as to what is causing the sleep dysfunction among pwME. How would you explain the sleep dysfunction experienced by pwME?

I think the dichotomy between disturbed sleep patterns and unrefreshing sleep is quite useful, keeping in mind however, that a pwME/CFS may have both.  Neither are unique to ME/CFS.

Disturbed sleep patterns (where the person is unable to sleep when they want to) may arise from co-morbidities with ME/CFS, such as sleep apnea, insomnia and circadian rhythm disorders. Sometimes the latter two disorders may begin with, or be perpetuated by, behavioural changes in sleep/wake behaviours that lead to disturbed sleep.

  • For example, the fatigue associated with ME/CFS may lead to irregular sleep patterns where the person sleeps episodically (i.e. naps) across the 24 hour period and the circadian (24 hour) rhythm becomes confused. The person’s sleep quality suffers because they are no longer getting their main sleep period in a single block at the time the body clock expects it. A different pattern that we may see in ME./CFS is Delayed Sleep Phase Disorder, where the person is very much an ‘evening’ type, going to bed late and getting up late. People who get insufficient outdoor light during the daytime are particularly susceptible to this.  Sometimes their body clock begins to ‘free run’ and each night they may go to bed later than the previous night, so their ‘day’ may be 25 hours instead of 24 hours.
  • Behavioural changes that may precipitate insomnia include decreased sleep drive (or sleep pressure) arising from reduced activity, significant napping during the day, reduced exposure to daytime light, worry at night about the consequences of having ME/CFS, and/or longer time in bed trying to sleep than the actual sleep duration that person may need. For example, due to boredom and/or feelings of fatigue, turning lights off from 9pm to 8am each night (i.e. 11 hours trying to sleep) when the person may only need 8 hours of actual sleep.  Best if lights-out time equals sleep time required.  The research shows quite clearly that treatment with Cognitive Behavioural Therapy for Insomnia can provide significant improvements in people whose sleep has been impaired by such behavioural factors and online programs are available.

On the other hand, disturbed sleep patterns in pwME/CFS may arise, not from behavioural factors, but from factors associated with ME/CFS itself, such as impaired melatonin secretion or other imbalances in the many hormonal or metabolic or neurological factors that we are only now beginning to understand affect sleep patterns.  Such imbalances may, in fact lead to either disturbed sleep patterns or unrefreshing sleep.

Unrefreshing sleep occurs across the population, both in people with a range of clinical conditions and sometimes in people with no diagnosed medical problem.  It is usually described by self-report. It is likely to be a very heterogenous phenomenon. A study by El-Mekkawy Leqaa et al (2022) noted a significant change in delta wave power (deep sleep) in the temporal brain region in those with unrefreshing sleep arising from sleep apnea, compared to controls. In our review of sleep patterns in ME/CFS (Jackson and Bruck, 2012) we concluded that technological advances in the assessment/monitoring of sleep may lead to further understanding of how the micro-structure of sleep may differ between those with self-reported unrefreshing sleep compared to quality sleep.

Q3. Anecdotal evidence from some pwME and a few research studies suggest that the sleep disturbance that people experience can have a significant impact on their cognitive abilities. How prevalent is this? What may be causing the sleep disturbance to impact people’s cognitive function?

Any ongoing sleep disturbance will affect a person’s cognitive abilities. Attention, concentration, memory and reaction time may all be affected in some way depending on (a) their overall health (physical and/or mental) and (b) individual differences in how poor sleep quality affects an individual.  It seems reasonable to think that a pwME/CFS that includes the symptom of brain fog would be affected by the cognitive impairments we associate with poor sleep in an additive way.

Q.4 Is there any evidence that non-restorative sleep is impacting other symptoms which pwME experience such as pain?

I believe that ANY ongoing poor quality sleep, whether it is unrestorative sleep or disturbed sleep will affect a range of ME/CFS symptoms, possibly all.  Pain and brain fog are likely to be particularly affected.

With regard to pain we know that sleep loss increases the experience of pain.  Krause et al (2019) showed that acute sleep deprivation amplifies pain reactivity within the human primary somatosensory cortex, lowers pain thresholds and that ‘even modest nightly changes in sleep quality within an individual determine consequential day-to-day changes in experienced pain’.

Q5. Having a clearer understanding about the pathophysiology of non-restorative sleep in pwME may lead to better treatment options for patients. Are you aware of any clinical trials which are exploring treatment issues for non-restorative sleep in pwME?

Unfortunately not.

Q6. Many people with M.E. report that there is a direct link between the degree of their non-restorative sleep and the depth of the fatigue they experience the next day. What research has been done into this particular issue and what were their findings?

To my knowledge this issue has not yet been investigated in pwME/CFS.  However, cognitive fatigue as measured on a range of working memory tests (Benkirane et al, 2022) found that the main effect of sleep fragmentation was to increase subjectively reported fatigue rather than reduce cognitive test performance.  This study, using healthy participants, highlights the difficulties in objectively measuring fatigue, as many people can rally their mental resources for short-term testing in a research setting.  This may have little to do with how fatigue is experienced in real-life settings.

Q7. What further research is required to investigate the causes of non-restorative sleep and the impact this has on cognitive function, fatigue and pain in pwME?

There are so many unanswered questions.  The first step for any such research is to have a standard definition of non-restorative sleep.  Is it a certain level of sleep fragmentation? Sleep disruption? Lower EEG delta power? Subjective report in the light of an otherwise normal sleep diary?  Is reported non-restorative sleep the same for someone with sleep apnea, vivid dreaming or ME/CFS?

The role of clinical neurophysiology in the definition and assessment of fatigue and fatigability

Highlights:

  • Though a common symptom, fatigue is difficult to define and investigate, and occurs in a wide variety of disorders, with differing pathological causes.
  • This review aims to guide clinicians in how to approach fatigue and to suggest that neurophysiological tests may allow an understanding of its origin and severity.
  • The effectiveness of neurophysiological tests as cost-effective objective biomarkers for the assessment of fatigue has been summarised.

Abstract

Though a common symptom, fatigue is difficult to define and investigate, occurs in a wide variety of neurological and systemic disorders, with differing pathological causes. It is also often accompanied by a psychological component. As a symptom of long-term COVID-19 it has gained more attention.

In this review, we begin by differentiating fatigue, a perception, from fatigability, quantifiable through biomarkers. Central and peripheral nervous system and muscle disorders associated with these are summarised. We provide a comprehensive and objective framework to help identify potential causes of fatigue and fatigability in a given disease condition. It also considers the effectiveness of neurophysiological tests as objective biomarkers for its assessment. Among these, twitch interpolation, motor cortex stimulation, electroencephalography and magnetencephalography, and readiness potentials will be described for the assessment of central fatigability, and surface and needle electromyography (EMG), single fibre EMG and nerve conduction studies for the assessment of peripheral fatigability.

The purpose of this review is to guide clinicians in how to approach fatigue, and fatigability, and to suggest that neurophysiological tests may allow an understanding of their origin and interactions. In this way, their differing types and origins, and hence their possible differing treatments, may also be defined more clearly.

Source: Tankisi H, Versace V, Kuppuswamy A, Cole J. The role of clinical neurophysiology in the definition and assessment of fatigue and fatigability. Clin Neurophysiol Pract. 2023 Dec 18;9:39-50. doi: 10.1016/j.cnp.2023.12.004. PMID: 38274859; PMCID: PMC10808861. https://www.sciencedirect.com/science/article/pii/S2467981X23000367 (Full text)

Immunosuppression in ME may underlie energy deficits that drive ME symptomology

Interview of Dr. Armin Alaedini by Bronc

In October of 2023 the UK the Department of Health and Social Care held a public consultation to improve the care/life outcomes for people with ME. It included an acknowledgement that there has been a lack of biomedical research into ME but failed to accept the very negative impact this has had on the lives of people living with the illness. It also failed to point the finger at those responsible for this which includes the National Institute of Clinical Excellence and the Medical Research Council amongst others.

Despite calling for more research into ME there is acknowledgement that this will need substantial sums of money for this to happen. The DHSC consultation also asked for views about its plans which included a section about disability benefits and how the Department of Work and Pensions wants to improve the service it provides to those people who claim disability benefits. This laughable comment ignores the war on people claiming disability benefits which has been waged by the DWP since 2010. To compound matters the British government recently announced that it wants to make it harder for people to claim disability benefits and snoop on their bank accounts.

The DWP has consistently failed to acknowledge the debilitating nature of ME and instead focuses on the fluctuating nature of the illness to deny many people with ME disability benefits such as ESA and PIP.

Thankfully, there is plenty of evidence revealing how people with ME suffer from a suppressed immune response which accounts for many of the debilitating symptoms of the illness.

I recently talked with Dr. Armin Alaedini about his recent research into this issue. Dr Alaedini is an assistant professor at Columbia University and principal investigator at the Alaedini Lab. Its research is aimed at identifying ‘novel biomarkers, understanding disease mechanism, and finding therapeutic targets in gastrointestinal and neuropsychiatric disease.’ He is chair of ME/CFS Biospecimen Resource Access Committee at the National Institute of Neurological Disorders and Stroke and a member of the Neurobiology of Pain Study Section at NIH.

Dr Alaedini took time out of his busy schedule to talk to me about his research into ME.

How did you get involved in the field of ME research?

I have always been interested in the study of complex medical conditions, especially those that are poorly understood and understudied. I became specifically involved in ME research because of my acquaintance with Dr. Suzanne Vernon, who at that time was the chief scientific officer at The Solve ME/CFS Initiative. I was fortunate to have her support for a NIH-funded project, which resulted in our recent publication that demonstrates how microbial translocation links gastrointestinal, immunologic, and metabolic defects in ME/CFS.

In the paper you co-authored, Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome, it notes that the relationship between immunologic, metabolic and gastrointestinal abnormalities remains unclear. In your study you examined two groups of people with ME: one at rest and one undergoing an exercise challenge. They were compared to a group of healthy people. Can you explain what differences you noted between the healthy control group and the people with ME and between the two groups of people with ME? What may have caused this elevated antibody response to microbial agents in people with ME?

I had been particularly intrigued by the fact that gastrointestinal complaints are common in ME/CFS. Data from the patients in our study clearly confirmed this, showing that gastrointestinal symptoms were indeed much more common and more severe in ME/CFS study participants than in the non-ME/CFS controls. Along with this, we found a specific marker of injury or damage to the intestinal lining, called FABP2, to be higher in the blood of ME/CFS participants than in controls, providing a potential biological link to least some of the associated gastrointestinal symptoms. Increased intestinal permeability due to damage can lead to greater translocation of dietary and microbial antigens, which are typically constrained within the gut lumen, across the intestinal barrier. This, in turn, may result in an immune response to those translocated dietary and microbial products to counter and remove the potentially inflammatory antigens from systemic circulation.

Indeed, our data pointed to a significant increase in antibody responses to microbial and dietary antigens in ME/CFS patients in comparison to controls. What especially surprised us, however, was the fact that we did not observe an expected rise in the more immediate, or what we call “acute-phase”, innate immune responses. Specifically, we found that despite the increased markers of intestinal damage and higher antibody responses, ME/CFS patients did not exhibit a significant acute-phase immune response to counter circulating microbial products. This was suggestive of a suppressed systemic immune response that could possibly explain some of the ME/CFS symptoms.

Your study also noted ‘Enhanced antibody response to dietary antigens in ME/CFS’. What might be causing this?

The antibody response to dietary antigens is likely part of the same process resulting from a dysfunctional intestinal barrier that results in an enhanced immune response to the contents of the gut lumen. These would include both microbial and dietary antigens that the immune system is generally tolerant to and does not mount a significant antibody response against under normal conditions.

People with ME suffer from post exertion malaise which means that exercise will exacerbate their symptoms. What differences did you note between the healthy participants and people with ME who took the exercise challenge? What might be causing the differences in their response to exercise?

Intense exercise is known to cause increased intestinal permeability. Therefore, a maximal exercise challenge can be a particularly useful tool to better understand the effect of gut barrier function on the dysfunctional immune responses we were seeing in the ME/CFS cohort. The data from the exercise challenge confirmed our earlier data, suggesting that ME/CFS patients have a dysfunctional immune response, characterized by a suppressed innate/acute-phase response that is ineffective at countering microbial translocation from the intestinal tract into systemic circulation.

At the same time, another part of the immune response, the adaptive immune system, tries to compensate for this dysfunction by producing antibodies against those microbial antigens. However, the antibody response appears to be inadequate, as the ME/CFS patients continued to have increased circulating microbial antigens. We hypothesize that these microbial antigens can trigger downstream inflammatory responses that impact the central nervous system and may contribute to some of the hallmark symptoms of ME/CFS, such as fatigue.

We also compared metabolic responses in response to exercise between ME/CFS and control study participants. Of particular significance, we found a suppression of glucose and citrate metabolic responses in ME/CFS that to some extent correlated with the suppressed innate immune responses in these patients. This dysfunctional metabolic response is not only conceivably capable of contributing to the observed immunosuppression in ME/CFS, but it may also further underlie energy deficits that drive ME/CFS symptomology.

In your study you observed an increase in antibody responses to both microbial and dietary antigens, reflecting greater epithelial cell damage, which point to enhanced translocation of gut luminal antigens across a compromised intestinal barrier in ME/CFS. Did your findings point to a possible treatment for this damage to the intestinal barrier?

Indeed, the data point to a number of potential targets to consider for therapy in the context of ME/CFS. These include reducing or repairing the intestinal damage in order to decrease the microbial translocation; blocking or sequestering the already translocated microbial antigens; reversing the identified defects in the acute-phase immune responses towards the microbial antigens, and targeting the suppressed metabolic pathways.

What further research is needed to address the issues highlighted in your study?

More research is needed to better understand the relevance and level of contribution of the identified defects in the intestinal barrier, immune response, and metabolic pathways to ME/CFS symptomology, as well as to further characterize the molecular pathways involved, in order to move this research closer to development of effective treatments for ME/CFS.

Post-exertional malaise in daily life and experimental exercise models in patients with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Post-exertional malaise (PEM) is commonly recognized as a hallmark of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and is often used as one of several criteria for diagnosing ME/CFS.

In this perspective paper we want to reflect on how PEM is understood, assessed, and evaluated in scientific literature, and to identify topics to be addressed in future research.

Studies show that patients use a wide variety of words and concepts to label their experience of PEM in everyday life, and they report physical or mental exertions as triggers of PEM. They also report that PEM may have an immediate or delayed onset and may last from a few days to several months.

When standardized exercise tests are used to trigger PEM experimentally, the exacerbation of symptoms has a more immediate onset but still shows a wide variability in duration.

There are indications of altered muscular metabolism and autonomic nervous responses if exercise is repeated on successive days in patients with ME/CFS. The decreased muscular capacity appears to be maintained over several days following such controlled exercise bouts. These responses may correspond to patients’ experiences of increased exertion.

Based on this background we argue that there is a need to look more closely into the processes occurring in the restitution period following exercise, as PEM reaches the peak in this phase.

Source: Nina K. Vøllestad, Anne Marit Mengshoel. Post-exertional malaise in daily life and experimental exercise models in patients with myalgic encephalomyelitis/chronic fatigue syndrome. Frontiers in Physiology, Volume 14- 2023. https://www.frontiersin.org/articles/10.3389/fphys.2023.1257557/abstract

Dry eye symptoms and signs in United States Gulf War era veterans with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Background: To examine ocular symptoms and signs of veterans with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) diagnosis, ME/CFS symptoms, and controls.

Methods: This was a prospective, cross-sectional study of 124 South Florida veterans in active duty during the Gulf War era. Participants were recruited at an ophthalmology clinic at the Miami Veterans Affairs Hospital and evaluated for a diagnosis of ME/CFS, or symptoms of ME/CFS (intermediate fatigue, IF) using the Canadian Consensus criteria. Ocular symptoms were assessed via standardised questionnaires and signs via comprehensive slit lamp examination. Inflammatory blood markers were analysed and compared across groups.

Results: Mean age was 55.1 ± 4.7 years, 88.7% identified as male, 58.1% as White, and 39.5% as Hispanic. Ocular symptoms were more severe in the ME/CFS (n = 32) and IF (n = 48) groups compared to controls (n = 44) across dry eye (DE; Ocular Surface Disease Index [OSDI]: 48.9 ± 22.3 vs. 38.8 ± 23.3 vs. 19.1 ± 17.8, p < 0.001; 5 item Dry Eye Questionnaire [DEQ-5]: 10.8 ± 3.9 vs. 10.0 ± 4.6 vs. 6.6 ± 4.2, p < 0.001) and pain-specific questionnaires (Numerical Rating Scale 1-10 [NRS] right now: 2.4 ± 2.8 vs. 2.4 ± 2.9 vs 0.9 ± 1.5; p = 0.007; Neuropathic Pain Symptom Inventory modified for the Eye [NPSI-E]: 23.0 ± 18.6 vs. 19.8 ± 19.1 vs. 6.5 ± 9.0, p < 0.001). Ocular surface parameters and blood markers of inflammation were generally similar across groups.

Conclusion: Individuals with ME/CFS report increased ocular pain but similar DE signs, suggesting that mechanisms beyond the ocular surface contribute to symptoms.

Source: Victor Sanchez BS, Colin K. Kim BS, Elyana V. T. Locatelli BS, Adam K. Cohen, Kimberly Cabrera MS, Kristina Aenlle PhD, Nancy G. Klimas MD, Robert O’Brien PhD, Anat Galor MD, MSPH. Dry eye symptoms and signs in United States Gulf War era veterans with myalgic encephalomyelitis/chronic fatigue syndrome. First published: 12 November 2023 https://doi.org/10.1111/ceo.14313 https://onlinelibrary.wiley.com/doi/10.1111/ceo.14313 (Full text)

Prevalence and Predictive Factors of Small Intestinal Bacterial Overgrowth in Patients With Chronic Fatigue Syndrome

Introduction: Chronic fatigue syndrome (CFS) is a poorly understood illness, characterized by fatigue and related symptoms including cognitive dysfunction, headaches, joint pains, and gastrointestinal distress. Irritable bowel syndrome (IBS) is common and present in approximately 60% patients with CFS while the prevalence of small intestinal bacterial overgrowth (SIBO) in IBS is approximately 40%. Our study aimed to 1) Determine the prevalence of SIBO in patients with CFS with and without IBS symptoms 2) Identify factors associated with increased risk of SIBO.

Methods: A retrospective chart review of 479 patients with CFS referred for hydrogen/methane breath testing. Clinical documentation was reviewed to identify positive breath test result diagnosing SIBO. Statistical analysis was conducted with 2-proportions z test and logistic regression analysis to identify predictive variables of SIBO diagnosis.

Results: 479 patients with CFS referred for glucose or lactulose breath testing were identified. Three hundred sixty-seven of those patients completed a breath test with available result: 152(41%) SIBO+ (mean age (SD) 50 (17)), 164(45%) SIBO- (mean age SD 46 (15)), and 78(21%) equivocal results. In CFS patients with conclusive breath test result, 48% tested positive for SIBO, and the diagnosis of IBS was present in 186/316 (59%). There was no difference in the prevalence of IBS between the SIBO+ vs SIBO-group [98/152 (64%) vs 88/164 (53%), P < 0.05]. Using multiple logistic regression analysis, age, unknown race, and IBS diagnosis all significantly predicted increased odds of having a positive breath test (Table 1). Conversely, PPI use was associated with decreased odds of a positive breath test. Due to the high prevalence of IBS in our cohort and the association between IBS and SIBO, an analysis was performed excluding patients with IBS diagnosis. When excluding patients with IBS, unknown race and TCA use were associated with increased odds of positive breath test, while diarrhea, hypothyroidism, PPI, and naltrexone use were associated with decreased odds (P< 0.05).

Conclusion: SIBO is highly prevalent in patients with CFS referred for breath testing. Older age and comorbid IBS diagnosis predict increased odds of positive breath test. Surprisingly, PPI use predicted decreased odds despite its prior implication as a possible risk factor for SIBO. Further studies are needed to explore the underlying mechanism causing the overlap between CFS, IBS and SIBO which may provide insights into potential therapies for CFS.

Source: Karhu, Elisa MD, MS; Neshatian, Leila MD, MS; Fass, Ofer MD; Sonu, Irene MD; Nguyen, Linda Anh MD. S1821 Prevalence and Predictive Factors of Small Intestinal Bacterial Overgrowth in Patients With Chronic Fatigue Syndrome. The American Journal of Gastroenterology 118(10S):p S1351-S1352, October 2023. | DOI: 10.14309/01.ajg.0000956924.26236.c4 https://journals.lww.com/ajg/fulltext/2023/10001/s1821_prevalence_and_predictive_factors_of_small.2162.aspx

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)