Evidence browser

E2 ModerateBehavioralPEM not requiredCross-Sectional

A measure of heart rate variability is sensitive to orthostatic challenge in women with chronic fatigue syndrome.

Yamamoto, Yoshiharu, LaManca, John J, Natelson, Benjamin H·Experimental biology and medicine (Maywood, N.J.)·2003

This study tested whether a simple heart rhythm measurement during a tilt test could help diagnose ME/CFS. Researchers compared heart rate patterns in 24 women with ME/CFS and 22 healthy women while they lay down and then tilted upright for 10 minutes. They found that women with ME/CFS showed a distinctive abnormal change in their heart rhythm pattern during tilting that could identify about 9 out of 10 ME/CFS patients correctly.

Autonomic Nervous System

Functional status, neuropsychological functioning, and mood in chronic fatigue syndrome (CFS): relationship to psychiatric disorder.

Tiersky, Lana A, Matheis, Robert J, Deluca, John et al.·The Journal of nervous and mental disease·2003

This study looked at how depression and anxiety affect people with ME/CFS. Researchers compared four groups: people with ME/CFS alone, people with ME/CFS plus mental health symptoms that started after CFS, people with ME/CFS plus mental health symptoms that started before CFS, and healthy controls. The main finding was that while mental health problems don't make the physical fatigue and weakness worse, they do make people feel more emotionally distressed—especially if those mental health issues came before the CFS diagnosis.

Cognitive Impairment

Multiple co-infections (Mycoplasma, Chlamydia, human herpes virus-6) in blood of chronic fatigue syndrome patients: association with signs and symptoms.

Nicolson, G L, Gan, R, Haier, J·APMIS : acta pathologica, microbiologica, et immunologica Scandinavica·2003

This study tested the blood of 200 ME/CFS patients and 100 healthy controls for three types of infections: Mycoplasma bacteria, Chlamydia bacteria, and human herpesvirus-6 (HHV-6). The researchers found that ME/CFS patients had significantly higher rates of these infections compared to healthy people, and patients with multiple infections at the same time tended to have more severe symptoms.

Functional status of persons with chronic fatigue syndrome in the Wichita, Kansas, population.

Solomon, Laura, Nisenbaum, Rosane, Reyes, Michele et al.·Health and quality of life outcomes·2003

This study surveyed people in Wichita, Kansas to understand how ME/CFS affects daily life and work. Researchers found that people with ME/CFS were just as impaired in their ability to work and do activities as people whose fatigue came from other medical or psychiatric conditions, and all of them had much less energy than people without fatigue.

Comparing symptoms of chronic fatigue syndrome in a community-based versus tertiary care sample.

Jason, Leonard A, Plioplys, Audrius V, Torres-Harding, Susan et al.·Journal of health psychology·2003

This study compared ME/CFS symptoms between two groups of patients: those who sought care at major medical centers and those found in the general community. Researchers found that people being treated at tertiary care hospitals reported experiencing more symptoms than community members with ME/CFS. This suggests that the people typically studied in research may not represent all people living with ME/CFS.

Diagnostics

E2 ModerateBehavioralPEM not requiredCross-Sectional

Perceived exertion in fatiguing illness: Gulf War veterans with chronic fatigue syndrome.

Cook, Dane B, Nagelkirk, Paul R, Peckerman, Arnold et al.·Medicine and science in sports and exercise·2003

This study compared how hard exercise felt to Gulf War veterans with ME/CFS versus healthy Gulf War veterans. Researchers had both groups exercise on stationary bikes while measuring their effort ratings. People with ME/CFS reported that the same amount of exercise felt much harder than it did for healthy veterans, even though they had similar physical fitness levels.

Post-Exertional Malaise

Psychiatric morbidity in the chronic fatigue syndrome: are patients with personality disorder more physically impaired?

Ciccone, Donald S, Busichio, Kim, Vickroy, Michael et al.·Journal of psychosomatic research·2003

This study looked at whether mental health conditions or personality traits explained why people with ME/CFS experience severe physical disability. Researchers compared 84 women with ME/CFS who had no psychiatric diagnosis, those with psychiatric illness, and those with both psychiatric illness and personality disorders. The key finding was that having mental health conditions did not explain the physical impairment and disability caused by ME/CFS—the disease itself, not psychiatric factors, was the primary driver of disability.

Comparison of subjective and objective measures of insomnia in monozygotic twins discordant for chronic fatigue syndrome.

Watson, Nathaniel F, Kapur, Vishesh, Arguelles, Lester M et al.·Sleep·2003

People with ME/CFS report feeling like they sleep poorly and don't rest well, but when researchers measured their actual sleep using medical equipment, the sleep looked similar to their healthy identical twins. The main difference was that people with ME/CFS had more REM sleep (a specific sleep stage) and felt much less refreshed after sleeping, even though the equipment showed they were sleeping normally. This suggests that ME/CFS may involve a mismatch between how sleep actually is and how it feels.

Sleep

RNase L levels in peripheral blood mononuclear cells: 37-kilodalton/83-kilodalton isoform ratio is a potential test for chronic fatigue syndrome.

Tiev, Kiet Phong, Demettre, Edith, Ercolano, Philippe et al.·Clinical and diagnostic laboratory immunology·2003

This study looked at a protein called RNase L in the immune cells of ME/CFS patients and healthy people. Researchers found that ME/CFS patients had a different pattern of RNase L forms compared to healthy volunteers, and this pattern could potentially be used as a simple blood test to help diagnose ME/CFS. The test showed promise in distinguishing ME/CFS patients from healthy people in this small group.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Perception of cognitive performance in patients with chronic fatigue syndrome.

Metzger, Fredric A, Denney, Douglas R·Annals of behavioral medicine : a publication of the Society of Behavioral Medicine·2002

This study looked at how accurately people with ME/CFS judge their own mental performance. When patients with ME/CFS completed a challenging thinking task, they consistently thought they did worse than they actually did, even though their actual performance matched healthy people's performance. This gap between what they thought they could do and what they actually accomplished was linked to how mentally tired and fatigued the task made them feel.

Cognitive Impairment

E2 ModerateBehavioralPEM not requiredObservational

Caring for a relative with chronic fatigue syndrome: difficulties, cognition and acceptance over time.

Ax, S, Gregg, V H, Jones, D·The journal of the Royal Society for the Promotion of Health·2002

This study spoke with 17 family members who care for people with ME/CFS to understand how the illness affects their lives. Surprisingly, many caregivers said their own daily lives weren't drastically changed, even though they all developed specific ways to cope and manage stress. Over time, caregivers learned to accept the illness, though this acceptance felt more like resignation than genuine understanding or appreciation of what the illness truly means.

E2 ModerateBehavioralPEM not requiredLongitudinal

Natural course and predicting self-reported improvement in patients with chronic fatigue syndrome with a relatively short illness duration.

van der Werf, Sieberen P, de Vree, Berna, Alberts, Maurice et al.·Journal of psychosomatic research·2002

This study followed 79 people with ME/CFS who had been ill for less than 2 years to see what happened over the next year without treatment. About 46% of these patients reported feeling better after one year, which is much higher than the 20% improvement rate seen in people who had been ill for longer. The study found that people who didn't improve tended to have worse concentration problems, fewer social supports, and didn't believe their illness had a physical cause.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Fractal analysis and recurrence quantification analysis of heart rate and pulse transit time for diagnosing chronic fatigue syndrome.

Naschitz, Jochanan E, Sabo, Edmond, Naschitz, Shaul et al.·Clinical autonomic research : official journal of the Clinical Autonomic Research Society·2002

This study tested a new way to diagnose ME/CFS by measuring how the heart and blood vessels respond to a simple tilt test (lying down then standing up). Researchers used mathematical analysis of heart rate patterns and blood flow timing to create a scoring system that could correctly identify ME/CFS patients 70% of the time. The test was safe and well-tolerated by participants.

Autonomic Nervous System

Fatigue after breast cancer and in chronic fatigue syndrome: similarities and differences.

Servaes, Petra, Prins, Judith, Verhagen, Stans et al.·Journal of psychosomatic research·2002

This study compared 57 women with ME/CFS to 57 women who had breast cancer and were experiencing severe fatigue after treatment. Researchers measured fatigue, physical activity, mood, sleep, and concentration using questionnaires, tests, and activity monitors worn for 12 days. While both groups experienced significant fatigue, ME/CFS patients generally had more severe symptoms overall, though some breast cancer survivors reported similar problems with sleep and concentration.

SleepCognitive Impairment

E2 ModerateCohortPEM unclearCase-Control

Chronic fatigue in a population-based study of Gulf War veterans.

McCauley, Linda A, Joos, Sandra K, Barkhuizen, Andre et al.·Archives of environmental health·2002

Researchers studied Gulf War veterans to see how many had chronic fatigue that couldn't be explained by standard medical tests. They found that about 2.2% of veterans met the official criteria for ME/CFS, and another 5.1% had unexplained fatigue. Women veterans were more likely to have these conditions than men. Unlike some other ME/CFS patients, most of these veterans developed their fatigue gradually rather than suddenly.

Diagnostics

Chronic fatigue syndrome and immune dysfunction: cause or effect?

Pollack, Shimon·The Israel Medical Association journal : IMAJ·2002

This study examined whether immune system problems in ME/CFS patients are a cause of the illness or a result of having the illness. Researchers compared immune markers between people with ME/CFS and healthy controls to understand this relationship better. The study helps clarify an important question: does a faulty immune system trigger ME/CFS, or does having ME/CFS damage the immune system over time?

Cellular immunity in monozygotic twins discordant for chronic fatigue syndrome.

Sabath, Daniel E, Barcy, Serge, Koelle, David M et al.·The Journal of infectious diseases·2002

This study looked at immune system differences in identical twins where one twin had ME/CFS and the other didn't. By comparing identical twins, researchers could focus on immune changes related to the illness rather than genetic differences. The study found that certain immune cells were more variable in twins with ME/CFS, suggesting the immune system may be less stable in this condition.