Category: Symptoms

Identifying post-exertional malaise subtypes: Differentiating physical and mental PEM manifestations

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic illness with post-exertional malaise (PEM) as a key symptom. This study categorized participants with ME/CFS who met PEM criteria into four groups based on severity of physical and mental PEM: severe physical PEM (Physical group), severe mental PEM (Mental group), both severe (Both group), or neither severe (Neither group). A control group was also included.

The Both group exhibited the highest symptom severity, while the Neither group displayed lower scores. The Neither group experienced less disability than other ME/CFS subtypes but was significantly more disabled than Controls. Health assessments revealed that Controls had the highest functioning, followed by the Neither group, with the Both group showing greatest impairment. These results indicate distinct PEM subtypes, emphasizing the need to recognize different manifestations of this complex symptom. Future research should include diverse control groups, longitudinal data, and biological measures to further understand PEM subtypes.

Source: Tuzzolino K, Jason LA, Furst J. Identifying post-exertional malaise subtypes: Differentiating physical and mental PEM manifestations. J Health Psychol. 2026 Feb 28:13591053261420598. doi: 10.1177/13591053261420598. Epub ahead of print. PMID: 41761780. https://pubmed.ncbi.nlm.nih.gov/41761780/

Temporal dynamics of the plasma proteomic landscape reveals maladaptation in ME/CFS following exertion

Abstract:

The overarching symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is post-exertional malaise (PEM), an exacerbation of symptoms following physical or mental exertion. To investigate the molecular underpinnings of PEM, we performed longitudinal plasma proteomics using the Somascan® 7K aptamer-based assay to monitor 6,361 unique plasma proteins in 132 individuals (96 females and 36 males) subjected to two maximal cardiopulmonary exercise tests separated by a 24-hour recovery period.

The cohort included 79 ME/CFS cases compared to 53 age- and BMI-matched sedentary controls, allowing us to distinguish disease-specific molecular alterations from those due to physical deconditioning. Longitudinal profiling revealed widespread proteomic changes following exertion, with the most pronounced alterations observed in ME/CFS participants during the recovery phase, coinciding with the onset of PEM.

Compared to controls, ME/CFS subjects showed persistent dysregulation of immune, metabolic, and neuromuscular pathways. Key findings included suppression of T and B cell signaling, downregulation of IL-17 and cell-cell communication pathways, and upregulation of glycolysis/gluconeogenesis, suggestive of mitochondrial stress and impaired immune recovery from exercise. Proteomic associations with physiological performance (VO2max, anaerobic threshold) revealed disruptions between protein abundance and exercise capacity in ME/CFS versus controls.

Correlations with symptom severity linked changes in immune-related proteins and ME/CFS symptoms including muscle pain, recurrent sore throat, and lymph node tenderness. Sex-stratified analyses revealed distinct molecular responses between females and males, emphasizing the importance of considering sex as a biological variable in ME/CFS research.

Finally, our analysis of sedentary controls contributes new data of molecular responses to acute exertion in a predominantly female sedentary cohort, a population historically underrepresented in exercise physiology studies. Together, these findings underscore the value of dynamic, proteomic profiling over time for characterizing maladaptive responses to exertion in ME/CFS and provide a foundation for deeper mechanistic investigation into PEM.

Source: Germain A, Glass KA, Eckert MA, Giloteaux L, Hanson MR. Temporal dynamics of the plasma proteomic landscape reveals maladaptation in ME/CFS following exertion. Mol Cell Proteomics. 2025 Nov 12:101467. doi: 10.1016/j.mcpro.2025.101467. Epub ahead of print. PMID: 41237904. https://www.mcponline.org/article/S1535-9476(25)00566-3/fulltext (Full text)

Understanding concussion in myalgic encephalomyelitis/chronic fatigue syndrome: Findings from the 2023 National Health Interview study

Abstract:

Background: Although myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) symptoms (dysautonomia, dizziness, balance impairments) may theoretically contribute to an association with concussion, the nature of this association has not been determined. This study explored the association between ME/CFS and concussion, as well as risk factors for concussion, history of recent falls, and feelings of being dizzy or off balance.

Method: 2023 National Health Interview Survey data were utilized. United States adults (unweighted N = 29,373) responded to items regarding sociodemographic factors, ME/CFS status, and history of concussion, falls, and feeling off balance or dizzy. Logistic regression analyses assessed the association between ME/CFS and concussion, falls, and feeling dizziness or balance problems within the past year, adjusting for sociodemographic factors.

Results: Individuals with ME/CFS had 4.89 times greater odds of reporting concussion in the past year compared to individuals without ME/CFS. Individuals with ME/CFS also had 2.86 times greater odds of having fallen within the past year and 5.88 times greater odds of reporting feeling dizzy or off balance in the past year.

Conclusions: ME/CFS status may be associated with concussion status. Healthcare practitioners should improve concussion screening and referrals for reducing concussion risk among individuals with ME/CFS.

Source: Sirotiak Z, Adamowicz JL, Thomas EBK. Understanding concussion in myalgic encephalomyelitis/chronic fatigue syndrome: Findings from the 2023 National Health Interview study. Brain Inj. 2025 Oct 16:1-8. doi: 10.1080/02699052.2025.2575479. Epub ahead of print. PMID: 41103060. https://pubmed.ncbi.nlm.nih.gov/41103060/

The association of fatigue and pain with cognitive test performance in patients with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Objectives: Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) typically perform worse on cognitive tasks compared to controls. The present study explored the independent associations of fatigue and pain symptoms with cognitive performance in a large sample of patients who met CDC criteria of CFS (n = 1375), of whom most also met NICE/ IOM criteria (n = 1072). Moreover, we tested the hypothesis that these associations become stronger with older age and longer symptom duration.

Methods: Questionnaires and diaries were employed assessing fatigue and pain severity, together with the impact of health problems on daily life (using the SF-36 ‘Physical Functioning’ and ‘Bodily Pain’ subscales). Cognitive outcomes consisted of speeded performance measures, namely the Symbol Digit Test, motor speed, simple and choice reaction time (RT), and response inhibition. Categorical regression with lasso penalization was employed to identify relevant correlates of cognitive performance.

Results: Fatigue severity remained as only correlate of response inhibition. For the other cognitive outcomes, fatigue severity consistently emerged together with contributions of pain severity, bodily pain and/or physical functioning. Restricting these analyses to those patients meeting NICE/IOM criteria revealed overall similar results. Age, not symptom duration, moderated several relationships, showing more pronounced associations between cognitive performance and pain severity, physical functioning, and bodily pain with older age.

Conclusions: This study highlights that a multidimensional nature of symptoms, including fatigue and pain severity, and the impact on daily-life functioning, relate to lower cognitive performance in patients with ME/CFS. Studies are needed to identify the direction and potential causality of these associations.

Source: Oosterman JM, van der Schaaf M, de Kleijn WPE, Kuut TA, Brazil IA, Knoop H. The association of fatigue and pain with cognitive test performance in patients with myalgic encephalomyelitis/chronic fatigue syndrome. J Psychosom Res. 2025 Oct 3;199:112401. doi: 10.1016/j.jpsychores.2025.112401. Epub ahead of print. PMID: 41101039. https://www.sciencedirect.com/science/article/pii/S0022399925003654 (Full text)

Autonomic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Findings from the Multi-Site Clinical Assessment of ME/CFS (MCAM) Study in the USA

Abstract:

Background/Objectives: Symptoms of autonomic dysfunction are common in infection-associated chronic conditions and illnesses (IACCIs), including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This study aimed to evaluate autonomic symptoms and their impact on ME/CFS illness severity.
Methods: Data came from a multi-site study conducted in seven ME/CFS specialty clinics during 2012–2020. Autonomic dysfunction was assessed using the Composite Autonomic Symptom Scale 31 (COMPASS-31), medical history, and a lean test originally described by the National Aeronautics and Space Administration (NASA). Illness severity was assessed using Patient-Reported Outcomes Measurement Information System measures, the 36-item short-form, as well as the CDC Symptom Inventory. This analysis included 442 participants who completed the baseline COMPASS-31 assessment, comprising 301 individuals with ME/CFS and 141 healthy controls (HC).
Results: ME/CFS participants reported higher autonomic symptom burden than HC across three assessment tools (all p < 0.0001), including the COMPASS-31 total score (34.1 vs. 6.8) and medical history indicators [dizziness or vertigo (42.6% vs. 2.8%), cold extremities (38.6% vs. 5.7%), and orthostatic intolerance (OI, 33.9% vs. 0.7%)]. Among ME/CFS participants, 97% had at least one autonomic symptom. Those with symptoms in the OI, gastrointestinal, and pupillomotor domains had significantly higher illness severity than those without these symptoms.
Conclusions: ME/CFS patients exhibit a substantial autonomic symptom burden that correlates with greater illness severity. Individualized care strategies targeting dysautonomia assessment and intervention may offer meaningful improvements in symptom management and quality of life for those with ME/CFS and similar chronic conditions.
Source: Issa A, Lin J-MS, Chen Y, Attell J, Brimmer D, Bertolli J, Natelson BH, Lapp CW, Podell RN, Kogelnik AM, et al. Autonomic Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Findings from the Multi-Site Clinical Assessment of ME/CFS (MCAM) Study in the USA. Journal of Clinical Medicine. 2025; 14(17):6269. https://doi.org/10.3390/jcm14176269  https://www.mdpi.com/2077-0383/14/17/6269 (Full text)

Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Debilitating symptoms for many years can follow acute COVID-19 (“long COVID”), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and various post-acute infection syndromes (PAISs). Together, long COVID and ME/CFS affect 60-400 million individuals, globally. Many similar underlying biological abnormalities have been identified in both conditions including autoantibodies against neural targets, endothelial dysfunction, acquired mitochondrial dysfunction, and a pro-inflammatory gut microbiome. Each of these abnormalities may directly cause some of the symptoms.

In addition, the symptoms also may be caused by ancient, evolutionarily conserved symptomatic and metabolic responses to vital threats-sickness behavior and torpor-responses mediated by specific, recently discovered neural circuits. These neural circuits constitute a symptom-generating pathway, activated by neuroinflammation, which may be targeted by therapeutics to quell neuroinflammation.

Many factors cause the symptoms to become chronic, including persistent infectious agents (and/or their nucleic acids and antigens) and the fact that many of the underlying biological abnormalities reinforce each other, creating ongoing physiological vicious cycles.

Source:Komaroff AL, Dantzer R. Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome. Cell Rep Med. 2025 Jul 25:102259. doi: 10.1016/j.xcrm.2025.102259. Epub ahead of print. PMID: 40744021. https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(25)00332-5 (Full text)

A Signal for Voice and Speech Abnormalities in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Background/Objectives: Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may report abnormalities in voice and speech; however, no formal research has been conducted in this area.
Methods: An online mixed-methods survey was completed by 685 people with ME/CFS. A total of 302 respondents completed the qualitative component (44.09%). Questions assessed disease experience with ME/CFS and post-exertional malaise without prompting on specific symptoms. Within the qualitative results, a search of the terms “speech, voice,” “words,” and “speak” was conducted.
Results: Excluding neurocognitive associations, colloquial phrases, and “speech therapy,” there were 38 mentions of the terms in the context of voice or speech changes across 28 unique qualitative survey responses (9.27%).
Conclusions: A notable portion of respondents reported voice or speech changes when responding to open-ended qualitative questions about their disease experience. More research is needed regarding the implications of voice and speech anomalies in ME/CFS pathology and disease monitoring.
Source: Grach SL, Seltzer J, Orbelo DM. A Signal for Voice and Speech Abnormalities in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Journal of Clinical Medicine. 2025; 14(14):4847. https://doi.org/10.3390/jcm14144847 https://www.mdpi.com/2077-0383/14/14/4847 (Full text)

The Implications and Predictability of Sleep Reversal for People with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Machine Learning Approach

Abstract:

Background/objectives: Impaired sleep is one of the core symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), yet the mechanisms and impact of sleep-related issues are poorly understood. Sleep dysfunctions for patients with ME/CFS include frequent napping, difficulties falling asleep, waking up early, and sleep reversal patterns (e.g., sleeping throughout the day and staying awake throughout the night). The current study focuses on sleep reversal for patients with ME/CFS.

Methods: We explored the symptoms and functional impairment of those with and without sleep reversal by analyzing the responses of a large international sample (N = 2313) using the DePaul Symptom Questionnaire (DSQ) and Medical Outcomes Study 36-item Short-Form Health Survey (SF-36).

Results: We found that those in our Sleep Reversal group (N = 327) compared to those without sleep reversal (N = 1986) reported higher symptom burden for 53 out of 54 DSQ symptoms and greater impairments for all six SF-36 subscales. The most accurate predictors of sleep reversal included age (p < 0.05), body mass index (p < 0.05), eleven DSQ symptoms (p < 0.01), and two SF-36 subscales (p < 0.01).

Conclusions: These features provide clues regarding some of the possible pathophysiological underpinnings of sleep reversal among those with ME/CFS.

Source: Dietrich MP, Pravin R, Furst J, Jason LA. The Implications and Predictability of Sleep Reversal for People with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Machine Learning Approach. Healthcare (Basel). 2025 May 26;13(11):1255. doi: 10.3390/healthcare13111255. PMID: 40508869. https://www.mdpi.com/2227-9032/13/11/1255 (Full text)

The Effect on Quality of Life of Therapeutic Plasmapheresis and Intravenous Immunoglobulins on a Population of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients with Elevated β-Adrenergic and M3-Muscarinic Receptor Antibodies—A Pilot Study

Abstract:

Background/Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition with not fully understood causes, though evidence points to immune system involvement and possible autoimmunity. ME/CFS could be triggered by various infectious pathogens, like SARS-CoV-2; furthermore, a subset of the post-COVID-19 condition (PCC) patients fulfill the diagnostic criteria of ME/CFS. According to the Canadian Consensus Criteria (CCC), the presence of specific symptoms such as fatigue, post-exertional malaise, sleep dysfunction, pain, neurological/cognitive manifestations, and symptoms from at least two of the following categories lead to the diagnosis of ME/CFS: autonomic, neuroendocrine, and immune manifestation. In this study, the patient selection was based on the identification of ME/CFS patients with elevated autoantibodies, regardless of the triggering factor of their condition.
Methods: The aim of this study was to identify ME/CFS patients among long COVID patients with elevated autoantibodies. In seven cases, plasmapheresis (PE) and intravenous immunoglobulins (IVIGs) with repetitive autoantibody measurements were applied: four PE sessions on days 1, 5, 30, and 60, and a low-dose IVIG therapy after each treatment. Antibodies were measured before the first PE and two weeks after the last PE session. To monitor clinical outcomes, the following somatic and psychometric follow-up assessments were conducted before the first PE, 2 weeks after the second, and 2 weeks after the last PE: the Schellong test, ISI (insomnia), FSS (fatigue), HADS (depression and anxiety), and EQ-5D-5L (quality of life) questionnaires.
Results: There was a negative association between both the β2-adrenergic and M3-muscarinic receptor autoantibody concentration and the quality of life measurements assessed with the EQ-5D-5L questionnaire. Per 1 U/mL increase in the concentration levels of β2-adrenergic receptor antibodies or M3-muscarinic acetylcholine receptor antibodies, the EQ-5D-5L index score [−0.59 to 1] decreased by 0.01 (0.63%) or 0.02 (1.26%), respectively. There were no significant associations between the ISI, HADS, and FSS questionnaires and the β1-adrenergic and M4-muscarinic receptor antibodies titers.
Conclusions: After a thorough selection of patients with present autoantibodies, this pilot study found negative associations concerning autoantibody concentration and somatic, as well as psychological wellbeing. To validate these promising feasibility study results—indicating the potential therapeutic potential of antibody-lowering methods—further investigation with larger sample sizes is needed.
Source: Oesch-Régeni B, Germann N, Hafer G, Schmid D, Arn N. The Effect on Quality of Life of Therapeutic Plasmapheresis and Intravenous Immunoglobulins on a Population of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients with Elevated β-Adrenergic and M3-Muscarinic Receptor Antibodies—A Pilot Study. Journal of Clinical Medicine. 2025; 14(11):3802. https://doi.org/10.3390/jcm14113802 https://www.mdpi.com/2077-0383/14/11/3802 (Full text)

Truncal ataxia or disequilibrium is an unrecognised cause of orthostatic intolerance in patients with myalgic encephalomyelitis

Introduction:

Chronic fatigue syndrome (CFS) causes a marked reduction in the activities of daily living and impairs the quality of life. Recently, dysfunction of the central nervous system associated with myalgic encephalomyelitis (ME) has been postulated as the main cause of CFS.1 Most patients with ME/CFS have orthostatic intolerance (OI) which is the primary factor restricting the daily functional capacity and in turn quality of life.2-4 OI is characterised by the inability to remain upright without severe signs and symptoms, such as hypotension, tachycardia, light-headedness, pallor, fatigue, weakness, dizziness, diminished concentration, tremulousness and nausea. Most symptoms of OI have been surmised to be related to reduced cerebral blood flow with or without impaired cerebral circulatory autoregulation, and the compensatory activation of the sympathetic nervous system.5, 6 Indeed, many patients have postural orthostatic tachycardia, delayed orthostatic hypotension and neurally mediated hypotension.4, 5, 7-9 Also many patients have low cardiac output in association with a small left ventricle.10-12 With further progression of the disease, patients may have even sitting intolerance and finally become bedridden.

Although static balance is an essential element for the performance of daily activities as well as postural stability, the possible relation between disequilibrium and OI has never been investigated. The possible role of static or truncal ataxia in the genesis of both orthostatic and sitting intolerance was examined in patients with ME.

Source: Miwa K, Inoue Y. Truncal ataxia or disequilibrium is an unrecognised cause of orthostatic intolerance in patients with myalgic encephalomyelitis. Int J Clin Pract. 2017 Jun;71(6). doi: 10.1111/ijcp.12967. PMID: 28613452. https://onlinelibrary.wiley.com/doi/10.1111/ijcp.12967 (Full text)