Evidence browser

Antioxidant status and lipoprotein peroxidation in chronic fatigue syndrome.

Manuel y Keenoy, B, Moorkens, G, Vertommen, J et al.·Life sciences·2001

This study looked at whether oxidative stress—a type of cellular damage—might contribute to ME/CFS. Researchers compared 33 people with ME/CFS to 28 people with similar symptoms who didn't meet ME/CFS criteria. They found that people with ME/CFS had higher levels of fat damage in their blood particles and lower levels of a protective protein called transferrin, suggesting their bodies may be more vulnerable to oxidative damage.

Physiological responses to incremental exercise in patients with chronic fatigue syndrome.

Inbar, O, Dlin, R, Rotstein, A et al.·Medicine and science in sports and exercise·2001

Researchers compared how the bodies of 15 people with ME/CFS responded to a gradually increasing exercise test on a treadmill, compared to 15 healthy people. People with ME/CFS showed lower heart rates and weaker cardiovascular responses during exercise, even when they appeared to be pushing themselves as hard as they could. This suggests their bodies may have trouble with either heart function or muscle oxygen use during physical exertion.

Working memory deficits associated with chronic fatigue syndrome.

Dobbs, B M, Dobbs, A R, Kiss, I·Journal of the International Neuropsychological Society : JINS·2001

This study tested memory and thinking skills in 20 people with ME/CFS and compared them to 20 healthy people. The researchers found that people with ME/CFS performed worse on difficult memory tasks, particularly those requiring quick mental switching and staying focused despite distractions. However, their basic memory storage ability was normal.

A family history study of chronic fatigue syndrome.

Walsh, C M, Zainal, N Z, Middleton, S J et al.·Psychiatric genetics·2001

This study examined whether ME/CFS runs in families by comparing relatives of people with ME/CFS to relatives of people with other medical conditions. Researchers found that relatives of ME/CFS patients were significantly more likely to also have ME/CFS, suggesting that family history and possibly genetics play a role in developing the condition.

E2 ModerateCohortPEM not requiredObservational

Urinary free cortisol in chronic fatigue syndrome.

Cleare, A J, Blair, D, Chambers, S et al.·The American journal of psychiatry·2001

This study measured a stress hormone called cortisol in the urine of people with ME/CFS and compared it to healthy controls. The researchers found that people with ME/CFS had lower cortisol levels than expected. This difference was consistent across the patient group and wasn't explained by depression, medications, sleep problems, or disability levels.

Endocrine Disruption

Antiviral pathway activation in patients with chronic fatigue syndrome and acute infection.

Gow, J W, Simpson, K, Behan, P O et al.·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·2001

Researchers compared two immune system defense pathways (RNase L and PKR) in people with ME/CFS, people with acute stomach infections, and healthy people. The immune pathways were only activated in people with acute infections, not in people with ME/CFS or healthy controls. This finding suggests that these particular immune markers cannot be used as a simple diagnostic test for ME/CFS.

Immune System

Divided attention deficits in patients with chronic fatigue syndrome.

Ross, S, Fantie, B, Straus, S F et al.·Applied neuropsychology·2001

This study compared thinking and attention abilities in people with ME/CFS and healthy controls. Researchers found that ME/CFS patients had specific trouble with divided attention—the ability to focus on two things at once (like listening to someone while reading). However, they performed normally on other cognitive tests like memory and word-finding. This suggests that ME/CFS affects one particular type of thinking rather than overall intelligence.

Cognitive compromise following exercise in monozygotic twins discordant for chronic fatigue syndrome: fact or artifact?

Claypoole, K, Mahurin, R, Fischer, M E et al.·Applied neuropsychology·2001

This study asked whether exercise makes thinking and memory problems worse in people with ME/CFS. Researchers tested 21 pairs of identical twins where one twin had ME/CFS and one did not, asking them to exercise until exhausted and then testing their memory, attention, and thinking speed. The twins with ME/CFS did not show worse cognitive decline after exercise compared to their healthy twin, suggesting that exercise itself does not damage thinking ability.

E2 ModerateCohortPEM unclearCross-Sectional

Cardiovascular responses of women with chronic fatigue syndrome to stressful cognitive testing before and after strenuous exercise.

LaManca, J J, Peckerman, A, Sisto, S A et al.·Psychosomatic medicine·2001

This study compared how the hearts and blood pressure of women with ME/CFS respond to stressful mental tasks compared to healthy women. Researchers found that women with ME/CFS had a weaker cardiovascular response to cognitive stress than healthy controls, and this pattern held true even after exercise. The study also found that women with more severe ME/CFS symptoms had the lowest cardiovascular responses to stress.

Is physical deconditioning a perpetuating factor in chronic fatigue syndrome? A controlled study on maximal exercise performance and relations with fatigue, impairment and physical activity.

Bazelmans, E, Bleijenberg, G, Van Der Meer, J W et al.·Psychological medicine·2001

This study tested whether ME/CFS patients are in poor physical condition compared to healthy people, and whether being out of shape might be making their illness worse. Researchers had 20 ME/CFS patients and 20 healthy controls perform exercise tests while measuring heart rate, oxygen use, and other body functions. The study found no significant difference in physical fitness between the two groups, suggesting that poor fitness is not the main reason ME/CFS patients struggle with exercise.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Illness perceptions and mood in chronic fatigue syndrome.

Edwards, R, Suresh, R, Lynch, S et al.·Journal of psychosomatic research·2001

This study looked at how ME/CFS patients' beliefs about their illness—such as what they think caused it, whether they can control it, and how long they expect it to last—relate to their mood and fatigue levels. Researchers surveyed 126 ME/CFS patients from a clinic and found that these beliefs were connected to both how tired patients felt and their levels of anxiety and depression, suggesting that what patients think about their illness may influence how much it affects them.

Circadian rhythm of core body temperature in subjects with chronic fatigue syndrome.

Hamilos, D L, Nutter, D, Gershtenson, J et al.·Clinical physiology (Oxford, England)·2001

Researchers wanted to know if ME/CFS might be caused by broken internal body clocks, similar to jet lag. They measured core body temperature continuously in 10 ME/CFS patients and 10 healthy controls over 48 hours and analyzed the patterns. The body temperature rhythms in ME/CFS patients looked almost identical to healthy people, suggesting a disrupted body clock is unlikely to be the main cause of ME/CFS symptoms.

Assessment of pentachlorophenol-exposed timber workers using a test-of-poisoning model.

Gorman, D, Monigatti, J, Glass, B et al.·International journal of occupational and environmental health·2001

This study looked at 62 former timber workers in New Zealand who were exposed to a toxic chemical called pentachlorophenol (PCP) during their jobs. Researchers found that some workers developed a cluster of symptoms including fever, headaches, breathing problems, and skin issues, while others developed a long-lasting fatigue that started while they were still working. However, the researchers concluded that these fatigue syndromes didn't clearly match what doctors expect from PCP poisoning, and many other factors could have caused the symptoms.

Clinicopathological findings consistent with primary Sjögren's syndrome in a subset of patients diagnosed with chronic fatigue syndrome: preliminary observations.

Sirois, D A, Natelson, B·The Journal of rheumatology·2001

Some people with ME/CFS experience dry eyes and dry mouth, which are also common symptoms of Sjögren's syndrome, an autoimmune disorder. This study tested 25 ME/CFS patients and 18 healthy volunteers for signs of Sjögren's syndrome using eye tests, saliva gland biopsies, and blood tests. The researchers found that about one-third of the ME/CFS patients had findings consistent with primary Sjögren's syndrome, while none of the healthy volunteers did.

Diagnostics

E2 ModerateBehavioralPEM not requiredCross-Sectional

Quantitative assessment of cerebral ventricular volumes in chronic fatigue syndrome.

Lange, G, Holodny, A I, DeLuca, J et al.·Applied neuropsychology·2001

This study looked at brain scans from people with ME/CFS to measure the size of fluid-filled spaces (ventricles) in their brains. Researchers found that people with ME/CFS had slightly larger ventricles compared to healthy controls, suggesting there may be subtle physical changes in the brains of some ME/CFS patients. While this difference was close to being statistically significant, it provides another piece of evidence that ME/CFS involves measurable brain changes.

Information processing in chronic fatigue syndrome: a preliminary investigation of suggestibility.

DiClementi, J D, Schmaling, K B, Jones, J F·Journal of psychosomatic research·2001

This study looked at how the brain processes information in people with ME/CFS compared to healthy people. Researchers found that people with ME/CFS reported more symptoms and were more easily influenced by suggestions, but they actually performed similarly to healthy people on memory and thinking tests. The findings suggest that how our brains automatically process information and respond to suggestions may affect how much people feel their thinking is impaired.

Health-related quality of life in patients with chronic fatigue syndrome: an international study.

Hardt, J, Buchwald, D, Wilks, D et al.·Journal of psychosomatic research·2001

This study measured how ME/CFS affects daily life and well-being in patients from the United States, United Kingdom, and Germany. Researchers found that patients in all three countries experienced very similar impacts on their quality of life—significantly worse than healthy people across most areas measured, including physical function, emotional health, and energy levels. The findings suggest that ME/CFS affects people similarly regardless of where they live.

Lack of association between HLA genotype and chronic fatigue syndrome.

Underhill, J A, Mahalingam, M, Peakman, M et al.·European journal of immunogenetics : official journal of the British Society for Histocompatibility and Immunogenetics·2001

Researchers tested whether certain immune system genes (HLA genes) were more common in ME/CFS patients compared to healthy people. They studied 58 ME/CFS patients and 134 healthy controls using modern genetic testing methods. They found no significant differences in HLA genes between the two groups, suggesting that these particular immune genes are not a major cause of ME/CFS.

Immune System

Intraindividual variability in cognitive performance in persons with chronic fatigue syndrome.

Fuentes, K, Hunter, M A, Strauss, E et al.·The Clinical neuropsychologist·2001

This study tested how well 14 people with ME/CFS and 16 healthy people could perform thinking tasks over 10 weeks. While the ME/CFS group completed tasks more slowly, they were just as accurate. The key finding was that people with ME/CFS showed much more inconsistency in their performance from week to week—sometimes doing better, sometimes worse—even when doing the same type of task.