New Therapy For Chronic Fatigue Syndrome To Be Tested

Press Release: A preliminary study suggests there may be hope in the offing for some sufferers of chronic fatigue syndrome with a new therapy being tested by researchers at the Stanford University School of Medicine.

José Montoya, MD, associate professor of medicine (infectious diseases), and postdoctoral scholar Andreas Kogelnik, MD, PhD, have used the drug valganciclovir – an antiviral often used in treating diseases caused by human herpes viruses – to treat a small number of CFS patients.

The researchers said they treated 25 patients during the last three years, 21 of whom responded with significant improvement that was sustained even after going off the medication at the end of the treatment regimen, which usually lasts six months. The first patient has now been off the drug for almost three years and has had no relapses. A paper describing the first dozen patients Montoya and Kogelnik treated with the drug was published in the December issue of Journal of Clinical Virology.

“This study is small and preliminary, but potentially very important,” said Anthony Komaroff, MD, professor of medicine at Harvard Medical School, who was not involved in the study. “If a randomized trial confirmed the value of this therapy for patients like the ones studied here, it would be an important landmark in the treatment of this illness.”

Montoya has received a $1.3 million grant from Roche Pharmaceutical, which manufactures the drug under the brand name Valcyte, to conduct a randomized, placebo-controlled, double-blind study set to begin this quarter at Stanford. The study will assess the effectiveness of the drug in treating a subset of CFS patients.

Montoya is speaking about his efforts at the biannual meeting of the International Association for Chronic Fatigue Syndrome in Fort Lauderdale on Jan. 11 and 12.

Chronic fatigue syndrome has baffled doctors and researchers for decades, because aside from debilitating fatigue, it lacks consistent symptoms. Although many genetic, infectious, psychiatric and environmental factors have been proposed as possible causes, none has been nailed down. It was often derided as “yuppie flu,” since it seemed to occur frequently in young professionals, though the Centers for Disease Control and Prevention says it’s most common in the middle-aged. But to those suffering from it, CFS is all too real and its effects are devastating, reducing once-vigorous individuals to the ranks of the bedridden, with an all-encompassing, painful and sleep-depriving fatigue.

More than 1 million Americans suffer from the disorder, according to the CDC. The disease often begins with what appears to be routine flulike symptoms, but then fails to subside completely – resulting in chronic, waxing and waning debilitation for years.

Valganciclovir is normally used against diseases caused by viruses in the herpes family, including cytomegalovirus, Epstein-Barr virus and human herpes virus-6. These diseases usually affect patients whose immune systems are severely weakened, such as transplant and cancer patients. Montoya, who had used the drug in treating such patients for years, decided to try using it on a CFS patient who came to him in early 2004 with extremely high levels of antibodies for three of the herpes family viruses in her blood. At the time, she had been suffering from CFS for five years.

When a virus infects someone, the levels of antibodies cranked out by the immune system in response typically increase until the virus is overcome, then slowly diminish over time. But Montoya’s patient had persistently high antibodies for the three viruses. In addition, the lymph nodes in her neck were significantly enlarged, some up to eight times their normal size, suggesting her immune system was fighting some kind of infection, even though a comprehensive evaluation had failed to point to any infectious cause.

Concerned about the unusual elevations in antibody levels as well as the swelling of her lymph nodes, Montoya decided to prescribe valganciclovir. “I thought by giving an antiviral that was effective against herpes viruses for a relatively long period of time, perhaps we could impact somehow the inflammation that she had in her lymph nodes,” said Montoya.

Within four weeks, the patient’s lymph nodes began shrinking. Six weeks later she phoned Montoya from her home in South America, describing how she was now exercising, bicycling and going back to work at the company she ran before her illness. “We were really shocked by this,” recalled Montoya.

Of the two dozen patients Montoya and Kogelnik have since treated, the 20 that responded all had developed CFS after an initial flulike illness, while the non-responders had suffered no initial flu.

Some of the patients take the drug for more than six months, such as Michael Manson, whose battle with CFS has lasted more than 18 years. The former triathlete was stricken with a viral infection a year after his marriage. After trying unsuccessfully to overcome what he thought were lingering effects of the flu, he had no choice but to drastically curtail all his activities and eventually stop working.

During his longest period of extreme fatigue, 13 1/2 weeks, Manson said, “My wife literally thought I was passing away. I could hear the emotion in her voice as she tried to wake me, but I couldn’t wake up to console her. That was just maddening.”

Now in his seventh month of treatment, Manson is able to go backpacking with his children with no ill after-effects. Prior to starting the treatment, Manson’s three children, ages 9 to 14, had never seen him healthy.

Montoya and Kogelnik emphasized that even if their new clinical trial validates the use of valganciclovir in treating some CFS patients, the drug may not be effective in all cases. In fact, the trial will assess the effectiveness of the medication among a specific subset of CFS patients; namely, those who have viral-induced dysfunction of the central nervous system.

“This could be a solution for a subset of patients, but that subset could be quite large,” said Kristin Loomis, executive director of the HHV-6 Foundation, which has helped fund a significant portion of the preparatory work for the clinical trial. “These viruses have been suspected in CFS for decades, but researchers couldn’t prove it because they are so difficult to detect in the blood. If Montoya’s results are confirmed, he will have made a real breakthrough.”

“What is desperately needed is the completion of the randomized, double-blind, placebo-controlled clinical trial that we are about to embark on,” Montoya said.

 

Source: Stanford University Medical Center. “New Therapy For Chronic Fatigue Syndrome To Be Tested.” ScienceDaily. ScienceDaily, 9 January 2007. https://www.sciencedaily.com/releases/2007/01/070108191506.htm

 

New Hypothesis Proposed For Cause Of Chronic Fatigue Syndrome

Press Release: COLUMBUS, Ohio — Researchers here have proposed a new theory for the cause of chronic fatigue syndrome (CFS) — one that blames the illness both on a low-level viral infection and on the body’s own immune response to that virus.

If true, it would offer an explanation for why virologists so far haven’t found evidence of a common virus when looking at a population of CFS patients. The hypothesis was included in a paper published in the current issue of the American Journal of Medicine.

The new theory, proposed by Ronald Glaser, professor of medical microbiology and immunology, and Janice Kiecolt-Glaser, professor of psychology and psychiatry at Ohio State University, is the latest work in more than two decades of their research on the effects of stress on the human immune system.

“Our data suggests that stress may be causing the expression of certain viral proteins and that these proteins may be modulating the body’s immune response, turning it on or off,”Glaser said.

CFS was first characterized by researchers in the mid-1980s who described it as a combination of symptoms including low-grade fevers, body aches, malaise, and depression among other signs. The condition seems more prevalent among young adult women. Those diagnosed with CFS often experience stress and depression.

Symptoms routinely linger for six months or more and may continue for years. The federal Centers for Disease Control and Prevention estimate that CFS may affect anywhere from four to 10 of every 100,000 people in the United States.

Other researchers have reported higher-than-normal titers of antibodies to various latent viruses — Epstein-Barr virus, cytomegalovirus, human herpes virus 6, for example — in the blood of patients diagnosed as having CFS. But no one viral infection was present in all patients — evidence that would be needed to prove a viral cause of the illness.

The Ohio State researchers’ new theory poses several mechanisms that might be linked to CFS.

Once a person is infected, these viruses can remain latent in the body for long periods of time. Glaser proposes that the viruses could be partially reactivated, that is, viral proteins could be produced at levels high enough to cause a low-grade infection but too low to be seen using current laboratory assays.

Glaser and Kiecolt-Glaser suggest that CFS patients may experience an ongoing, low-grade viral infection — more like a smoldering fire rather than a three-alarm blaze — which could stimulate parts of the immune response without raising antibody titers to typically high levels.

That low-grade infection would be enough to increase production of various cytokines — chemical mediators for the immune system — and begin the immune response.

“A lot of the symptoms that you find in chronic fatigue syndrome are the same ones induced by cytokines during our normal immune response,” Glaser said.

He admits that studies of patients have yet to show a pattern of abnormal cytokine behavior that would substantiate their theory but he has an explanation for that.

“We haven’t discovered all the cytokines involved in immunity. We may not have found the right one, yet,” he said, adding that new cytokines are steadily being identified.

Stress and depression may be playing a related role as well, Kiecolt-Glaser said. Earlier research has repeatedly shown that increased stress and depression can reactivate latent viruses, decrease the body’s immune response, and stimulate the production of certain cytokines linked to some CFS-like symptoms.

“Part of this is a chicken-and-egg problem,” Kiecolt-Glaser said. “People diagnosed with CFS often are depressed since they’re unable to carry out normal, daily activities. What we don’t know is whether the depression followed the diagnosis of CFS or if CFS contributed to it.

“We do know, however, that this kind of depression can weaken our immune response.”

Glaser said researchers need to reconsider past work on CFS.

“We need to look for immune system changes that are much more subtle and specific than those we’ve been using as benchmarks,” he said.

 

Source: Ohio State University. “New Hypothesis Proposed For Cause Of Chronic Fatigue Syndrome.” ScienceDaily. ScienceDaily, 3 November 1998. https://www.sciencedaily.com/releases/1998/10/981031180910.htm

Chronic Fatigue Syndrome Impairs A Person’s Slow Wave Activity During Sleep

Press Release: Chronic fatigue syndrome (CFS) has been associated with altered amounts of slow wave sleep, which could reflect reduced electroencephalograph (EEG) activity and impaired sleep regulation. A study published in the journal SLEEP finds that CFS is also associated with a blunted slow wave activity (SWA) response to sleep challenge, suggesting an impairment of the basic sleep drive and homeostatic response.

The study, authored by Roseanna Armitage, PhD, and colleagues at the University of Michigan, focused on 13 pairs of identical twins discordant for CFS. Analyses, which were restricted to the first four non-REM periods each night in order to show comparability, revealed that SWA, or other sleep EEG measures, did not differ between the CFS and healthy twins during a regular night’s sleep. According to Armitage, it was only after a “challenge” to sleep regulation was introduced (keeping them awake an extra four hours) that the CFS twins exhibited significantly less SWA power in the first non-REM period of recovery sleep and accumulated a smaller percentage of SWA in the first non-REM period than their twin counterparts.

“CFS shares symptoms with depression, and some experts have suggested that it is not a distinctly different disorder,” said Armitage. “We have also conducted studies of SWA response to sleep challenge in depression, and the results are very different. Depressed women did not show a blunted SWA response to sleep challenge. The present CFS study included only women, and none had current depression. Therefore, our results cannot be explained on the basis of depression.”

Experts recommend that adults get between seven and eight hours of sleep each night to maintain good health and optimum performance. Persons who think they might have a sleep disorder are urged to consult with their primary care physician, who will refer them to a sleep specialist.

Article: “The Impact of a Four-Hour Sleep Delay on Slow Wave Activity in Twins Discordant for Chronic Fatigue Syndrome”, Sleep, May 1, 2007.

 

Source: American Academy of Sleep Medicine. “Chronic Fatigue Syndrome Impairs A Person’s Slow Wave Activity During Sleep.” ScienceDaily. ScienceDaily, 7 May 2007. www.sciencedaily.com/releases/2007/05/070501075253.htm

Research Provides More Evidence That Chronic Fatigue Syndrome Is A Legitimate Medical Condition

Press Release: Researchers at Georgetown University Medical Center have found that chronic fatigue syndrome (CFS) may be rooted in distinct neurological abnormalities that can be medically tested. Although the sample studied was small, this research provides objective, physiological evidence that the controversial disorder can be considered a legitimate medical condition.

Chronic fatigue syndrome defines a range of illnesses including fibromyalgia and Gulf War syndrome, all of which have fatigue as a major symptom. Even among medical professionals, there is a disagreement about the causes, diagnosis and treatment of CFS because so much about the disorder remains unknown. One reason CFS is difficult to diagnose is because it shares symptoms with many other diseases, including multiple sclerosis and lupus. Even when other illnesses are ruled out and a CFS diagnosis is given, there is not a standardized course of treatment and it’s difficult for doctors to measure patient improvement. Estimates are that two to four times as many women as men are diagnosed with CFS.

The Georgetown study, published in the November edition of the BMC Neurology Journal, an online publication, reveals that patients diagnosed with CFS and its family of illnesses have a set of proteins in their spinal cord fluid that were not detected in healthy individuals. These proteins might give insight into the causes of CFS and could someday be used as markers to diagnose patients with the disorder.

“For years, patients with chronic fatigue syndrome have suffered from painful symptoms for which there is no blood test, diagnosable physical condition or any method for doctors to measure improvement,” said James Baraniuk, MD, assistant professor of medicine at Georgetown University Medical Center and first author on the study. “Our research provides initial evidence that chronic fatigue syndrome and its family of illnesses may be legitimate, neurological diseases and that at least part of the pathology involves the central nervous system.”

The disorder is characterized by profound fatigue that is not improved by bed rest and that may get worse with physical or mental activity, according to the Centers for Disease Control and Prevention. Persons with CFS usually function at a lower level of activity than they were capable of before the onset of illness, feeling too tired to perform normal activities or easily exhausted with no apparent reason. Patients also report various nonspecific symptoms, including weakness, muscle pain, impaired memory and/or mental concentration, insomnia and post-exertional fatigue lasting more than 24 hours.

The study looked at 50 individuals suffering from at least two disorders related to CFS, including fibromyalgia and Gulf War syndrome. By examining spinal cord fluid in patients with CFS and in healthy individuals, the researchers found that CFS patients have 16 proteins that healthy individuals do not. Five of these 16 proteins are found in all patients with the illnesses but in none of the controls. The results indicate that those 16 proteins could possibly serve as a “biosignature” for the disease and could someday be used to diagnose CFS.

“Although this is a small study and more research on the subject is necessary, these results indicate it might be possible to develop a simple laboratory test to diagnose these disorders in the future,” Baraniuk said.

Other co-authors on the paper include Begona Casada, PhD, and Hilda Maibach, MS, of Georgetown University Medical Center; Daniel J. Clauw, MD, of the University of Michigan; and Lewis K. Pannell, PhD, of the University of South Carolina; and Sonya Hess, PhD, of the National Institute of Diabetes and Digestive and Kidney Diseases.

 

Source: Georgetown University Medical Center. “Research Provides More Evidence That Chronic Fatigue Syndrome Is A Legitimate Medical Condition.” ScienceDaily. ScienceDaily, 10 January 2006. www.sciencedaily.com/releases/2006/01/060110013424.htm

Chronic Fatigue: Clues In The Blood

Press Release: University of New South Wales, July 8, 2007. Researchers at UNSW believe that blood may hold vital insights into what is happening in the brain of patients with chronic fatigue syndrome (CFS).

In a study unparalleled in its scope, a team led by UNSW Professor Andrew Lloyd of the Centre for Infection and Inflammation Research, has studied the differences in gene expression patterns in the blood of people who either recover promptly after acute glandular fever or develop the prolonged illness called post-infective syndrome.

The researchers examined six million pieces of gene expression information for analysis in the project, known as the Dubbo Infection Outcomes Study. The study is named after the NSW town in which the work was conducted. The team studied the expression of 30,000 genes in the blood, testing each of the 15 individuals between four and five times over a 12-month period.

The team was able to narrow its findings to the expression of just 35 genes whose pattern of expression correlated closely with the key symptoms of the illness when examined from onset through to recovery. Gene expression is significant because it is the process by which a gene’s DNA sequence is converted into the proteins which ultimately determine the manifestations of disease.

Since 1999, the team has been tracking the long-term health of individuals infected with Ross River virus (RRV), Q fever infection and Epstein-Barr virus, which causes glandular fever.

“These [35] genes might point to the nature of the disease process that underlies CFS, which is currently unknown,” said Professor Lloyd, who is based in the School of Medical Sciences at UNSW. “None of them are ones that I would have predicted, except for those relating to neurotransmitters,” he concedes. “Some of them relate to transport of zinc and other metal ions within the cell, which may suggest a fundamental disturbance in cellular function.”

The researchers now hope to narrow the focus of research onto the expression of these 35 genes in the blood of a much larger group of subjects from the Dubbo Infection Outcomes Study, with varied patterns of illness and recovery.

“There are very few complex diseases which have been comprehensively analysed, with large scale and longitudinal studies, like this,” said Professor Lloyd. “It sets a standard for highly sophisticated, comprehensive gene expression studies in the blood of all sorts of human diseases from rheumatoid arthritis and multiple sclerosis through to schizophrenia.”

The research paper has been published in the Journal of Infectious Diseases.

 

Source: University of New South Wales. “Chronic Fatigue: Clues In The Blood.” ScienceDaily. ScienceDaily, 8 July 2007. https://www.sciencedaily.com/releases/2007/07/070706090020.htm

Epigenetic modifications and glucocorticoid sensitivity in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Abstract:

BACKGROUND: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating idiopathic disease characterized by unexplained fatigue that fails to resolve with sufficient rest. Diagnosis is based on a list of symptoms and exclusion of other fatigue-related health conditions. Despite a heterogeneous patient population, immune and hypothalamic-pituitary-adrenal (HPA) axis function differences, such as enhanced negative feedback to glucocorticoids, are recurring findings in ME/CFS studies. Epigenetic modifications, such as CpG methylation, are known to regulate long-term phenotypic differences and previous work by our group found DNA methylome differences in ME/CFS, however the relationship between DNA methylome modifications, clinical and functional characteristics associated with ME/CFS has not been examined.

METHODS: We examined the DNA methylome in peripheral blood mononuclear cells (PBMCs) of a larger cohort of female ME/CFS patients using the Illumina HumanMethylation450 BeadChip Array. In parallel to the DNA methylome analysis, we investigated in vitro glucocorticoid sensitivity differences by stimulating PBMCs with phytohaemagglutinin and suppressed growth with dexamethasone. We explored DNA methylation differences using bisulfite pyrosequencing and statistical permutation. Linear regression was implemented to discover epigenomic regions associated with self-reported quality of life and network analysis of gene ontology terms to biologically contextualize results.

RESULTS: We detected 12,608 differentially methylated sites between ME/CFS patients and healthy controls predominantly localized to cellular metabolism genes, some of which were also related to self-reported quality of life health scores. Among ME/CFS patients, glucocorticoid sensitivity was associated with differential methylation at 13 loci.

CONCLUSIONS: Our results indicate DNA methylation modifications in cellular metabolism in ME/CFS despite a heterogeneous patient population, implicating these processes in immune and HPA axis dysfunction in ME/CFS. Modifications to epigenetic loci associated with differences in glucocorticoid sensitivity may be important as biomarkers for future clinical testing. Overall, these findings align with recent ME/CFS work that point towards impairment in cellular energy production in this patient population.

 

Source: de Vega WC, Herrera S, Vernon SD, McGowan PO. Epigenetic modifications and glucocorticoid sensitivity in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). BMC Med Genomics. 2017 Feb 23;10(1):11. doi: 10.1186/s12920-017-0248-3. https://www.ncbi.nlm.nih.gov/pubmed/28231836

 

Gross and fine motor function in fibromyalgia and chronic fatigue syndrome

Abstract:

PURPOSE: This paper aimed to investigate motor proficiency in fine and gross motor function, with a focus on reaction time (RT) and movement skill, in patients with fibromyalgia (FM) and chronic fatigue syndrome (CFS) compared to healthy controls (HC).

METHODS: A total of 60 individuals (20 CFS, 20 FM, and 20 HC), age 19-49 years, participated in this study. Gross motor function in the lower extremity was assessed using a RT task during gait initiation in response to an auditory trigger. Fine motor function in the upper extremity was measured during a precision task (the Purdue Pegboard test) where the number of pins inserted within 30 s was counted.

RESULTS: No significant differences were found between FM and CFS in any parameters. FM and CFS groups had significantly longer RT than HC in the gait initiation (p=0.001, and p=0.004 respectively). In the Purdue Pegboard test, 20% in the FM group, 15% in the CFS groups, and 0% of HC group, scored below the threshold of the accepted performance. However, there were no significant differences between FM, CFS, and HC in this task (p=0.12).

CONCLUSION: Compared to controls, both CFS and FM groups displayed significantly longer RT in the gait initiation task. Generally, FM patients showed the worst results in both tests, although no group differences were found in fine motor control, according to the Purdue Pegboard test.

 

Source: Rasouli O, Fors EA, Borchgrevink PC, Öhberg F, Stensdotter AK. Gross and fine motor function in fibromyalgia and chronic fatigue syndrome. J Pain Res. 2017 Feb 7;10:303-309. doi: 10.2147/JPR.S127038. ECollection 2017. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5304994/ (Full article)

 

Assessing current functioning as a measure of significant reduction in activity level

Abstract:

BACKGROUND: Myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) have case definitions with varying criteria, but almost all criteria require an individual to have a substantial reduction in activity level. Unfortunately, a consensus has not been reached regarding what constitutes substantial reductions. One measure that has been used to measure substantial reduction is the Medical Outcomes Study Short Form-36 Health Survey (SF-36).[1].

PURPOSE: The current study examined the relationship between the SF-36, a measure of current functioning, and a self-report measure of the percent reduction in hours spent on activities.

RESULTS: Findings indicated that select subscales of the SF-36 accurately measure significant reductions in functioning. Further, this measure significantly differentiates patients from controls.

CONCLUSION: Determining what constitutes a significant reduction in activity is difficult because it is subjective to the individual. However, certain subscales of the SF-36 could provide a uniform way to accurately measure and define substantial reductions in functioning.

 

Source: Thorpe T, McManimen S, Gleason K, Stoothoff J, Newton JL, Strand EB, Jason LA. Assessing current functioning as a measure of significant reduction in activity level. Fatigue. 2016;4(3):175-188. doi: 10.1080/21641846.2016.1206176. Epub 2016 Jul 19. https://www.ncbi.nlm.nih.gov/pubmed/28217427

 

Neural Consequences of Post-Exertion Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Post exertion malaise is one of the most debilitating aspects of Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome, yet the neurobiological consequences are largely unexplored. The objective of the study was to determine the neural consequences of acute exercise using functional brain imaging.

Fifteen female Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients and 15 healthy female controls completed 30 minutes of submaximal exercise (70% of peak heart rate) on a cycle ergometer. Symptom assessments (e.g. fatigue, pain, mood) and brain imaging data were collected one week prior to and 24 hours following exercise.

Functional brain images were obtained during performance of: 1) a fatiguing cognitive task – the Paced Auditory Serial Addition Task, 2) a non-fatiguing cognitive task – simple number recognition, and 3) a non-fatiguing motor task – finger tapping. Symptom and exercise data were analyzed using independent samples t-tests. Cognitive performance data were analyzed using mixed-model analysis of variance with repeated measures. Brain responses to fatiguing and non-fatiguing tasks were analyzed using linear mixed effects with cluster-wise (101-voxels) alpha of 0.05.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients reported large symptom changes compared to controls (effect size ≥0.8, p<0.05). Patients and controls had similar physiological responses to exercise (p>0.05). However, patients exercised at significantly lower Watts and reported greater exertion and leg muscle pain (p<0.05).

For cognitive performance, a significant Group by Time interaction (p<0.05), demonstrated pre- to post-exercise improvements for controls and worsening for patients. Brain responses to finger tapping did not differ between groups at either time point. During number recognition, controls exhibited greater brain activity (p<0.05) in the posterior cingulate cortex, but only for the pre-exercise scan. For the Paced Serial Auditory Addition Task, there was a significant Group by Time interaction (p<0.05) with patients exhibiting increased brain activity from pre- to post-exercise compared to controls bilaterally for inferior and superior parietal and cingulate cortices.

Changes in brain activity were significantly related to symptoms for patients (p<0.05). Acute exercise exacerbated symptoms, impaired cognitive performance and affected brain function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients.

These converging results, linking symptom exacerbation with brain function, provide objective evidence of the detrimental neurophysiological effects of post-exertion malaise.

Published by Elsevier Inc.

 

Source: Cook DB, Light AR, Light KC, Broderick G, Shields MR, Dougherty RJ, Meyer JD, VanRiper S, Stegner AJ, Ellingson LD, Vernon SD. Neural Consequences of Post-Exertion Malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Brain Behav Immun. 2017 Feb 16. pii: S0889-1591(17)30051-X. doi: 10.1016/j.bbi.2017.02.009. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/28216087

 

Validation of the Flinders Fatigue Scale as a measure of daytime fatigue

Abstract:

STUDY OBJECTIVES: To clinically validate the Flinders Fatigue Scale (FFS) as a brief measure of daytime fatigue, and to derive cut-off scores to classify fatigue severity.

METHOD: The FFS was administered to 439 adult volunteers from the general population, 292 adults with insomnia, 132 adults with Obstructive Sleep Apnoea (OSA) and 66 adults with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME), together with the Fatigue Severity Scale (FSS) and the Epworth Sleepiness Scale (ESS).

RESULTS: A factor analysis revealed a single factor solution for the seven-item scale (67% of total variance), although a better fit was obtained for a modified six-item version (75% of total variance). Group FFS scores varied in accordance with theorised fatigue levels, with CFS/ME and insomnia samples reporting significantly higher fatigue than OSA and volunteer samples. Good convergent validity was established with the FSS for volunteer (r = 0.67) and CFS/ME samples (r = 0.61). Excellent discriminant validity with the ESS was observed for the insomnia (r = -0.08) and CFS/ME groups (r = 0.03), while a small-to-moderate correlation was found within the volunteer sample (r = 0.29). Cut-off scores were identified to categorise borderline (13-15), moderate (16-20) and severe (≥21) fatigue.

CONCLUSIONS: The FFS is a reliable and valid instrument to quantify subjective daytime fatigue. Sensitivity and specificity analyses indicate scores that best discriminate insomniacs and CFS/ME populations from a non-clinical population. However, it is proposed that the data can also be used to indicate the severity of fatigue by reference to these first two groups.

Copyright © 2016. Published by Elsevier B.V.

 

Source: Cameron K, Williamson P, Short MA, Gradisar M. Validation of the Flinders Fatigue Scale as a measure of daytime fatigue. Sleep Med. 2017 Feb;30:105-112. doi: 10.1016/j.sleep.2016.11.016. Epub 2016 Dec 3. https://www.ncbi.nlm.nih.gov/pubmed/28215232