ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

2768 studies

581–600 of 2,768 studies

E2 ModerateCohortPEM not requiredCross-Sectional

Post-COVID-19 Syndrome: Retinal Microcirculation as a Potential Marker for Chronic Fatigue.

Schlick, Sarah, Lucio, Marianna, Wallukat, Gerd et al.·International journal of molecular sciences·2022

Researchers studied whether tiny blood vessels in the eye could be a measurable sign of fatigue in people with long COVID. Using a special imaging technique to look at blood vessels in the retina (back of the eye), they found that people with long COVID—especially women—had reduced blood flow in these tiny vessels compared to healthy people. Those with long COVID who reported severe fatigue had even lower blood vessel density than those with milder fatigue, suggesting the eye scan might objectively confirm what patients report feeling.

Biomarkers

E2 ModerateCohortPEM not requiredObservational

Transitional Changes in Fatigue-Related Symptoms Due to Long COVID: A Single-Center Retrospective Observational Study in Japan.

Nakano, Yasuhiro, Otsuka, Yuki, Honda, Hiroyuki et al.·Medicina (Kaunas, Lithuania)·2022

This study compared long COVID symptoms in patients infected with different COVID-19 variants (Delta vs. Omicron) in Japan. Patients infected with Omicron had milder initial illness but were more likely to experience fatigue, sleep problems, and ongoing cough. Those infected with Delta were more likely to lose their sense of taste or smell and experience hair loss.

Sleep

E2 ModerateCohortPEM requiredObservational

A 2-day cardiopulmonary exercise test in chronic fatigue syndrome patients who were exposed to humidifier disinfectants.

Leem, Jong-Han, Jeon, Hyoung-Eun, Nam, Hun et al.·Environmental analysis, health and toxicology·2022

This study tested whether a special two-day exercise test could detect post-exertional malaise (PEM)—the worsening of symptoms after physical activity—in people with ME/CFS who had been exposed to humidifier disinfectants. The researchers had 29 participants complete an exercise test, rest for 24 hours, then repeat it. They found that performance noticeably declined on the second day, showing that PEM is real and measurable.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCross-Sectional

Pathway Phenotypes Underpinning Depression, Anxiety, and Chronic Fatigue Symptoms Due to Acute Rheumatoid Arthritis: A Precision Nomothetic Psychiatry Analysis.

Smesam, Hasan Najah, Qazmooz, Hasan Abbas, Khayoon, Sinan Qayes et al.·Journal of personalized medicine·2022

This study looked at 118 people with rheumatoid arthritis (RA, an autoimmune disease affecting joints) and 50 healthy people to understand why RA patients often experience depression, anxiety, and fatigue. Researchers measured immune system markers and psychological symptoms, finding that about 70% of these mental and fatigue symptoms could be explained by the same immune system problems that cause RA itself.

Immune System

E2 ModerateCohortPEM not requiredCross-Sectional

Exposure-response relationship between K. brevis blooms and reporting of upper respiratory and neurotoxin-associated symptoms.

Abdullah, L, Ferguson, S, Niedospial, D et al.·Harmful algae·2022

Researchers studied whether harmful algal blooms caused by Karenia brevis (a type of seaweed) in Florida's Gulf waters trigger respiratory symptoms, headaches, and nerve-related illness symptoms in people living nearby. They surveyed 258 residents in five coastal counties and found a clear link: when blooms were stronger, more people reported these symptoms. People with previous diagnoses of migraines, chronic fatigue syndrome, or memory problems were more likely to report these symptoms during blooms.

E2 ModerateCohortPEM unclearCross-Sectional

The Significance of Pain Drawing as a Screening Tool for Cervicogenic Headache and Associated Symptoms in Chronic Fatigue.

Bernhoff, Gabriella, Huhmar, Helena M, Rasmussen-Barr, Eva et al.·Journal of pain research·2022

This study looked at whether a simple drawing tool could help identify a specific type of headache (cervicogenic headache) in people with ME/CFS. Researchers found that 42% of ME/CFS patients had a particular pain pattern on their drawings that suggested their headache came from their neck. Patients with this neck-related pain pattern also experienced more dizziness, worse pain, and lower quality of life compared to others.

Pain and Sensitization

E2 ModerateDiagnosticPEM not requiredMethods-Paper

Comparison of assessment scores for fatigue between multidimensional fatigue inventory (MFI-K) and modified chalder fatigue scale (mKCFQ).

Lim, Eun-Jin, Son, Chang-Gue·Journal of translational medicine·2022

This study compared two questionnaires used to measure fatigue: the Multidimensional Fatigue Inventory (MFI-K) and the modified Chalder Fatigue Scale (mKCFQ). Researchers asked 70 people with varying levels of fatigue to complete both questionnaires and then analyzed how similarly the two tools measured fatigue. Both questionnaires showed strong agreement overall, but they measured different aspects of fatigue with varying accuracy.

E2 ModerateCohortPEM unclearCase-Control

Genetic and epigenetic regulation of Catechol-O-methyltransferase in relation to inflammation in chronic fatigue syndrome and Fibromyalgia.

Polli, Andrea, Hendrix, Jolien, Ickmans, Kelly et al.·Journal of translational medicine·2022

This study looked at how genes and chemical changes in DNA affect a protein called COMT, which plays a role in pain and inflammation in ME/CFS and fibromyalgia. Researchers compared 28 patients with these conditions to 26 healthy people and measured pain sensitivity, genetic variants, and immune markers. They found that certain genetic patterns and DNA changes were linked to symptoms and immune responses, suggesting that how our genes are "switched on or off" may contribute to these conditions.

E2 ModerateCohortPEM not requiredCross-Sectional

Survey of Anti-Pathogen Antibody Levels in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

O'Neal, Adam J, Glass, Katherine A, Emig, Christopher J et al.·Proteomes·2022

Researchers tested blood samples from ME/CFS patients to look for antibodies against 122 different germs that might trigger the illness. They compared the results to healthy people of similar age, sex, and weight. While they found differences in how men and women with ME/CFS respond to infections, they couldn't identify one specific germ as the culprit.

Immune System

E2 ModerateCohortPEM unclearCross-Sectional

Differences in Symptoms among Black and White Patients with ME/CFS.

Jason, Leonard A, Torres, Chelsea·Journal of clinical medicine·2022

This study looked at whether ME/CFS symptoms differ between Black and White patients. Researchers compared 19 Black patients with ME/CFS to White patients with ME/CFS and healthy people without the condition. They found that ME/CFS patients had notably different symptoms compared to healthy controls, but Black and White ME/CFS patients reported very similar symptom patterns.

E2 ModerateBehavioralPEM unclearObservational

Performance Validity and Outcome of Cognitive Behavior Therapy in Patients with Chronic Fatigue Syndrome.

Roor, Jeroen J, Dandachi-FitzGerald, Brechje, Peters, Maarten J V et al.·Journal of the International Neuropsychological Society : JINS·2022

This study looked at whether certain types of memory test performance could predict how well people with ME/CFS would respond to cognitive behavioral therapy (CBT). Researchers tested 1,081 patients before and after CBT treatment. While test scores didn't predict treatment outcomes for people who stuck with the program, patients with lower test scores were more likely to drop out of treatment early. The key finding is that if people with lower scores stayed in treatment, they actually improved just as much as others.

E2 ModerateCohortPEM unclearCross-Sectional

Comparison of the finger plethysmography derived stroke volumes by Nexfin CO Trek and suprasternal aortic Doppler derived stroke volume measurements in adults with myalgic encephalomyelitis/chronic fatigue syndrome and in healthy controls.

van Campen, C Linda M C, Verheugt, Freek W A, Rowe, Peter C et al.·Technology and health care : official journal of the European Society for Engineering and Medicine·2021

This study compared two different ways of measuring how much blood the heart pumps with each beat during a tilt table test (where patients lie down then are tilted upright). Researchers tested 154 ME/CFS patients and 39 healthy people using finger cuff measurements and ultrasound of the heart. They found that the finger cuff method gave higher readings than ultrasound, but after adjusting the finger cuff numbers to match ultrasound values, the device became reliable enough to track changes during tilt testing.

Autonomic Nervous System

E2 ModerateCohortPEM unclearCross-Sectional

A Comprehensive Examination of Severely Ill ME/CFS Patients.

Chang, Chia-Jung, Hung, Li-Yuan, Kogelnik, Andreas M et al.·Healthcare (Basel, Switzerland)·2021

This study examined severely ill ME/CFS patients who are mostly housebound or bedbound—a group that hasn't received much research attention. Researchers found that fatigue, pain, and thinking difficulties were the most common complaints, and patients showed distinct sleep problems and hormone imbalances. The study suggests that ME/CFS and long COVID may share similar mechanisms, meaning treatments discovered for one condition could potentially help the other.

Long COVID OverlapPost-Exertional Malaise

E2 ModerateCohortPEM unclearCase-Control

Central sensitisation in chronic fatigue syndrome and fibromyalgia; a case control study.

Bourke, Julius H, Wodehouse, Theresa, Clark, Lucy V et al.·Journal of psychosomatic research·2021

This study tested whether ME/CFS and fibromyalgia involve a condition called 'central sensitisation,' where the nervous system becomes overly sensitive to pain signals. Researchers compared pain sensitivity in 19 ME/CFS patients, 19 fibromyalgia patients, and 20 healthy people using physical tests. They found that 84% of ME/CFS patients and 95% of fibromyalgia patients showed signs of central sensitisation, while none of the healthy controls did.

Pain and Sensitization

E2 ModerateCohortPEM unclearCross-Sectional

Kynurenine metabolites and ratios differ between Chronic Fatigue Syndrome, Fibromyalgia, and healthy controls.

Groven, Nina, Reitan, Solveig Klæbo, Fors, Egil Andreas et al.·Psychoneuroendocrinology·2021

This study examined a specific metabolic pathway in the blood called the kynurenine pathway, which affects how the brain functions. Researchers compared blood samples from people with ME/CFS, people with fibromyalgia, and healthy people to see if the chemical breakdown products in this pathway differed. They found that the balance of certain chemicals was different in people with these conditions, and these differences may relate to fatigue and pain symptoms.

NeuroinflammationEnergy Metabolism

E2 ModerateCohortPEM not requiredLongitudinal

Association between chronic fatigue syndrome and suicidality among survivors of Middle East respiratory syndrome over a 2-year follow-up period.

Ahn, So-Hyun, Kim, Jeong Lan, Kim, Jang Rae et al.·Journal of psychiatric research·2021

This study followed people who recovered from MERS (a serious respiratory illness) for 2 years to see if chronic fatigue increased their risk of suicidal thoughts. Researchers found that people who had chronic fatigue were about 7.5 times more likely to experience suicidal thoughts than those without fatigue. This connection remained strong even when accounting for other factors that might affect mental health.

E2 ModerateCohortPEM not requiredLongitudinal

Relationship between Cardiopulmonary, Mitochondrial and Autonomic Nervous System Function Improvement after an Individualised Activity Programme upon Chronic Fatigue Syndrome Patients.

Kujawski, Sławomir, Cossington, Jo, Słomko, Joanna et al.·Journal of clinical medicine·2021

This study tested whether a personalized activity program could help ME/CFS patients feel less tired and function better. Thirty-four patients followed a 16-week program tailored to their individual abilities. After the program, patients reported significant improvements in fatigue, and blood tests showed improvements in mitochondrial markers (Mfn1 and Mfn2)—the energy-producing components of cells. However, about half of the patients found exercise difficult to tolerate.

Autonomic Nervous SystemPost-Exertional Malaise

E2 ModeratePEM unclearRegistry-Resource

Prevalence and characteristics of self-reported hypothyroidism and its association with nonorgan-specific manifestations in US sarcoidosis patients: a nationwide registry study.

Alzghoul, Bashar N, Amer, Farah N, Barb, Diana et al.·ERJ open research·2021

This study looked at how common thyroid problems are in sarcoidosis patients and how they relate to other symptoms. Researchers found that about 1 in 7 sarcoidosis patients reported having an underactive thyroid (hypothyroidism), and these patients were more likely to experience fatigue, depression, sleep problems, and difficulty with physical activities. The study suggests that checking for thyroid problems might help doctors better manage sarcoidosis symptoms.

E2 ModerateCohortPEM not requiredObservational

Infections in temporal proximity to HPV vaccination and adverse effects following vaccination in Denmark: A nationwide register-based cohort study and case-crossover analysis.

Krogsgaard, Lene Wulff, Petersen, Irene, Plana-Ripoll, Oleguer et al.·PLoS medicine·2021

This study examined whether having an infection around the time of HPV vaccination increases the risk of developing illness symptoms afterward in Danish women. Researchers found that women who had a treated infection within one month before or after their first HPV vaccine dose were more likely to later seek care at specialized centers for suspected vaccine side effects. The symptoms reported were similar to those seen in chronic fatigue syndrome.

E2 ModerateCohortPEM unclearObservational

Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study.

Eccles, Jessica A, Thompson, Beth, Themelis, Kristy et al.·Clinical medicine (London, England)·2021

This study looked at whether joint hypermobility (unusual flexibility and loose joints) is connected to fibromyalgia and ME/CFS. Researchers found that most patients with these conditions also had signs of hypermobility, and that higher hypermobility scores matched with worse symptoms. The results suggest that hypermobility is often missed in diagnosis, even though it significantly affects how sick people feel.

Diagnostics

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Post-COVID-19 Syndrome: Retinal Microcirculation as a Potential Marker for Chronic Fatigue.

Transitional Changes in Fatigue-Related Symptoms Due to Long COVID: A Single-Center Retrospective Observational Study in Japan.

A 2-day cardiopulmonary exercise test in chronic fatigue syndrome patients who were exposed to humidifier disinfectants.

Pathway Phenotypes Underpinning Depression, Anxiety, and Chronic Fatigue Symptoms Due to Acute Rheumatoid Arthritis: A Precision Nomothetic Psychiatry Analysis.

Exposure-response relationship between K. brevis blooms and reporting of upper respiratory and neurotoxin-associated symptoms.

The Significance of Pain Drawing as a Screening Tool for Cervicogenic Headache and Associated Symptoms in Chronic Fatigue.

Comparison of assessment scores for fatigue between multidimensional fatigue inventory (MFI-K) and modified chalder fatigue scale (mKCFQ).

Genetic and epigenetic regulation of Catechol-O-methyltransferase in relation to inflammation in chronic fatigue syndrome and Fibromyalgia.

Survey of Anti-Pathogen Antibody Levels in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Differences in Symptoms among Black and White Patients with ME/CFS.

Performance Validity and Outcome of Cognitive Behavior Therapy in Patients with Chronic Fatigue Syndrome.

Comparison of the finger plethysmography derived stroke volumes by Nexfin CO Trek and suprasternal aortic Doppler derived stroke volume measurements in adults with myalgic encephalomyelitis/chronic fatigue syndrome and in healthy controls.

A Comprehensive Examination of Severely Ill ME/CFS Patients.

Central sensitisation in chronic fatigue syndrome and fibromyalgia; a case control study.

Kynurenine metabolites and ratios differ between Chronic Fatigue Syndrome, Fibromyalgia, and healthy controls.

Association between chronic fatigue syndrome and suicidality among survivors of Middle East respiratory syndrome over a 2-year follow-up period.

Relationship between Cardiopulmonary, Mitochondrial and Autonomic Nervous System Function Improvement after an Individualised Activity Programme upon Chronic Fatigue Syndrome Patients.

Prevalence and characteristics of self-reported hypothyroidism and its association with nonorgan-specific manifestations in US sarcoidosis patients: a nationwide registry study.

Infections in temporal proximity to HPV vaccination and adverse effects following vaccination in Denmark: A nationwide register-based cohort study and case-crossover analysis.

Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study.

Curated Collections

Neuroinflammation Evidence

Metabolism & Mitochondria

Biomarkers

PEM-Specific Research