Evidence browser

E2 ModerateCohortPEM unclearCross-Sectional

Blood volume and its relation to peak O(2) consumption and physical activity in patients with chronic fatigue.

Farquhar, William B, Hunt, Brian E, Taylor, J Andrew et al.·American journal of physiology. Heart and circulatory physiology·2002

This study looked at whether people with ME/CFS have lower blood volume (the amount of fluid circulating in their bodies) and whether this might explain their exercise problems. Researchers compared 17 ME/CFS patients with 17 healthy controls, measuring blood volume and fitness capacity. They found that ME/CFS patients had significantly reduced exercise capacity and a trend toward lower blood volume, and these two measurements were strongly related to each other.

Post-Exertional Malaise

Immunological variables mediate cognitive dysfunction in gulf war veterans but not civilians with chronic fatigue syndrome.

Brimacombe, Michael, Zhang, QuanWu, Lange, Gudrun et al.·Neuroimmunomodulation·2002

This study compared immune system markers and thinking/memory problems in Gulf War veterans with ME/CFS and civilians with ME/CFS. The researchers found that in Gulf War veterans, certain immune system patterns were connected to cognitive problems like slower reaction times, and these immune changes seemed to affect how well they could function. Interestingly, this same immune-cognition relationship was not found in civilians with ME/CFS, suggesting the two groups may have different underlying causes for their illness.

Hemodynamics instability score in chronic fatigue syndrome and in non-chronic fatigue syndrome.

Naschitz, Jochanan E, Sabo, Edmond, Naschitz, Shaul et al.·Seminars in arthritis and rheumatism·2002

Researchers developed a simple scoring system to measure how much a person's blood pressure and heart rate fluctuate during a tilt test (where patients lie flat then are tilted upright). They found that ME/CFS patients had much more unstable blood pressure and heart rate compared to healthy people, people with other types of fatigue, and even people who faint unexpectedly. This instability might be a useful marker to help diagnose ME/CFS.

Autonomic instability, as measured by pupillary unrest, is not associated with multiple sclerosis fatigue severity.

Egg, R, Högl, B, Glatzl, S et al.·Multiple sclerosis (Houndmills, Basingstoke, England)·2002

This study looked at whether problems with the nervous system's ability to regulate automatic body functions (like pupil responses) might explain fatigue in multiple sclerosis patients. Researchers measured pupil movements in MS patients and healthy volunteers, then compared these measurements to fatigue severity scores. Surprisingly, they found the opposite of what they expected: people with more pupil instability actually reported less fatigue, not more.

E2 ModerateCohortPEM not requiredObservational

Analysis of 16S rRNA gene sequences and circulating cell-free DNA from plasma of chronic fatigue syndrome and non-fatigued subjects.

Vernon, Suzanne D, Shukla, Sanjay K, Conradt, Jennifer et al.·BMC microbiology·2002

Researchers tested whether bacteria in the bloodstream might be linked to ME/CFS by analyzing blood samples from people with ME/CFS and healthy controls. They found that healthy people had more detectable bacterial DNA in their blood than ME/CFS patients did, and no unique or unusual bacteria were found in either group. This suggests that a specific bacterial infection is unlikely to be a primary cause of ME/CFS.

A six-month trial of valacyclovir in the Epstein-Barr virus subset of chronic fatigue syndrome: improvement in left ventricular function.

Lerner, A Martin, Beqaj, Safedin H, Deeter, Robert G et al.·Drugs of today (Barcelona, Spain : 1998)·2002

This small study tested whether an antiviral medication called valacyclovir could help ME/CFS patients who had persistent Epstein-Barr virus (EBV) infection. Researchers gave 25 patients valacyclovir for 6 months and found that those with only EBV infection showed improvement in heart function and energy levels, but those with both EBV and cytomegalovirus infections did not improve.

Cytokines in nasal lavage fluids from acute sinusitis, allergic rhinitis, and chronic fatigue syndrome subjects.

Repka-Ramirez, Susana, Naranch, Kristina, Park, Yong-Jin et al.·Allergy and asthma proceedings·2002

Researchers measured inflammation markers in nasal fluid samples from people with ME/CFS, allergic rhinitis, acute sinusitis, and healthy controls. They found that people with acute sinusitis had significantly higher levels of inflammatory substances, but people with ME/CFS did not show elevated inflammation in their nasal passages compared to healthy controls.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Physicians' diagnoses of psychiatric disorders for people with chronic fatigue syndrome.

Torres-Harding, Susan R, Jason, Leonard A, Cane, Victoria et al.·International journal of psychiatry in medicine·2002

This study looked at whether doctors correctly identify psychiatric conditions (like depression or anxiety) in patients with ME/CFS compared to other groups. Researchers found that doctors often missed psychiatric disorders when they were present, but they rarely incorrectly diagnosed someone as having a psychiatric condition when they didn't. Interestingly, patients themselves were often better at recognizing their own psychiatric symptoms than their physicians were.

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 requiredCross-Sectional

Fatigue in chronic migraine patients.

Peres, M F P, Zukerman, E, Young, W B et al.·Cephalalgia : an international journal of headache·2002

This study looked at fatigue in 63 patients with chronic migraine headaches. The researchers found that most of these patients experienced significant fatigue, and many met the diagnostic criteria for chronic fatigue syndrome (CFS). The study suggests that fatigue and migraines may be connected conditions that should be recognized and treated together.

E2 ModerateCohortPEM unclearCross-Sectional

Latent class analysis of symptoms associated with chronic fatigue syndrome and fibromyalgia.

Sullivan, P F, Smith, W, Buchwald, D·Psychological medicine·2002

Researchers studied 646 patients with ME/CFS and/or fibromyalgia to see if these are truly separate conditions or if they overlap significantly. Using statistical analysis of 32 common symptoms, they found that patients fell into four groups that differed in severity rather than type—suggesting these conditions are more similar to each other than previously thought. This challenges the traditional belief that ME/CFS and fibromyalgia are distinct disorders.

Diagnostics

E2 ModerateBehavioralPEM not requiredObservational

Radiophobia: long-term psychological consequences of Chernobyl.

Pastel, Ross H·Military medicine·2002

After the Chernobyl nuclear accident, many people experienced psychological distress and developed symptoms like extreme fatigue, sleep problems, mood changes, memory difficulties, and muscle or joint pain. These symptom patterns resembled chronic fatigue syndrome and fibromyalgia. Importantly, these symptoms appeared in people across both highly and minimally contaminated areas and didn't increase with radiation exposure levels, suggesting psychological stress rather than radiation damage caused the illness.

E2 ModerateCohortPEM unclearCross-Sectional

Antinuclear autoantibodies (ANA) in Gulf War-related illness and chronic fatigue syndrome (CFS) patients.

Skowera, A, Stewart, E, Davis, E T et al.·Clinical and experimental immunology·2002

This study looked for a specific type of immune protein called antinuclear autoantibodies (ANAs) in people with ME/CFS and Gulf War veterans with multiple symptoms. Researchers compared blood samples from ME/CFS patients, symptomatic Gulf War veterans, and healthy controls. They found no significant differences in ANA levels between any of the groups, and none of the patients had the specific nuclear envelope ANA type that had been suggested as a possible ME/CFS marker.

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.

E2 ModerateCohortPEM not requiredCase-Control

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.

Physical performance and prediction of 2-5A synthetase/RNase L antiviral pathway activity in patients with chronic fatigue syndrome.

Snell, Christopher R, Vanness, J Mark, Strayer, David R et al.·In vivo (Athens, Greece)·2002

This study looked at whether exercise test results could predict high levels of RNase L, an enzyme that may be involved in ME/CFS. Researchers asked 73 patients to exercise until they were exhausted, and found that those with elevated RNase L had lower exercise capacity than those with normal levels. The findings suggest that simple exercise tests might help doctors identify which ME/CFS patients have this particular biological abnormality.

BiomarkersImmune System

Impaired postural cerebral hemodynamics in young patients with chronic fatigue with and without orthostatic intolerance.

Tanaka, Hidetaka, Matsushima, Reiko, Tamai, Hiroshi et al.·The Journal of pediatrics·2002

This study measured how blood flow to the brain changes when young people with ME/CFS stand up, compared to healthy controls. Researchers found that many ME/CFS patients—especially those who feel dizzy or have a racing heart when standing—did not get the normal quick boost of oxygen to their brain that healthy people do. This suggests that problems with brain blood flow during position changes may be connected to ME/CFS symptoms.