Chronic Fatigue Syndrome Research Research Articles

Frontiers in chronic fatigue syndrome research: An analysis of the top 100 most influential articles in the field.

Chronic fatigue syndrome (CFS) is a complex constellation of symptoms that significantly reduces the quality of life among affected individuals and increases public health expenditures. We conducted a search on the Web of Science Core Collection database and selected the top 100 cited articles in the field of CFS. Several literature analysis tools, including CiteSpace 6.1.R6, VOSviewer 1.6.19, and Scimago Graphica 1.0.30, were utilized to integrate the most influential research papers and academic journals in order to obtain a comprehensive understanding of the CFS field. The top 100 highly-cited publications were published in 67 reputable journals, with contributions from 250 institutions across 26 countries/regions involved in CFS research. This demonstrates the extensive attention and coverage of CFS research by high-quality academic journals and institutions, highlighting the interdisciplinary and multidisciplinary nature of CFS studies. The journal with the highest publication volume and total citations was Lancet. The top 5 co-occurring keywords were chronic fatigue syndrome, cognitive behavior therapy, epidemiology, definition, and disorders, indicating the ongoing attention researchers have devoted to the diagnostic criteria and clinical studies of CFS. Cluster analysis results suggested that primary care, infectious retrovirus, gene expression, and metabolomics may become the focal points and trends in future CFS research. The prospective research directions in this field include the search for biological markers, with a particular focus on immunology; the advancement of diagnostic techniques; the screening of risk genes associated with CFS; and the conduct of epidemiological investigations.

Discussion based on the popularity of "A reboot for chronic fatigue syndrome research"

Discussion based on the popularity of "A reboot for chronic fatigue syndrome research"

Lawsuit at Columbia University roils prominent chronic fatigue syndrome research lab

Lawsuit at Columbia University roils prominent chronic fatigue syndrome research lab

Unexpected findings and promoting monocausal claims, a cautionary tale.

Stories of serendipitous discoveries in medicine incorrectly imply that the path from an unexpected observation to major discovery is straightforward or guaranteed. In this paper, I examine a case from the field of research about chronic fatigue syndrome (CFS). In Norway, an unexpected positive result during clinical care has led to the development of a research programme into the potential for the immunosuppressant drug rituximab to relieve the symptoms of CFS. The media and public have taken up researchers' speculations that their research results indicate a causal mechanism for CFS - consequently, patients now have great hope that 'the cause' of CFS has been found, and thus, a cure is sure to follow. I argue that a monocausal claim cannot be correctly asserted, either on the basis of the single case of an unexpected, although positive, result or on the basis of the empirical research that has followed up on that result. Further, assertion and promotion of this claim will have specific harmful effects: it threatens to inappropriately narrow the scope of research on CFS, might misdirect research altogether, and could directly and indirectly harm patients. Therefore, the CFS case presents a cautionary tale, illustrating the risks involved in drawing a theoretical hypothesis from an unexpected observation. Further, I draw attention to the tendency in contemporary clinical research with CFS to promote new research directions on the basis of reductive causal models of that syndrome. Particularly, in the case of CFS research, underdetermination and causal complexity undermine the potential value of a monocausal claim. In sum, when an unexpected finding occurs in clinical practice or medical research, the value of following up on that finding is to be found not in the projected value of a singular causal relationship inferred from the finding but rather in the process of research that follows.

Lobbyists seek new funds for chronic fatigue syndrome research

Lobbyists seek new funds for chronic fatigue syndrome research

The use of mixed methods in studying a chronic illness

This article explores mixed-method approaches with an illness called myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Qualitative and Quantitative data were used to investigate the epidemiology of this illness, as well as explore attributions based on the name of the illness, and finally treatment approaches. In each of the domains within the ME and CFS research reviewed, our analyses were richer and our findings ultimately more impactful when we integrated qualitative and quantitative research methods. The use of a multiphase mixed-methods research program provided our team unique vantage points for better understanding social and community issues involving this controversial chronic illness. Furthermore, this approach allowed us to implement the insights gained through an advocacy lens to change policy, recommend and evaluate treatments, and amplify voices within the patient population. In this way, we believe that the practice of methodological pluralism is especially applicable and effective to the study of chronic illness, and believe that other investigators will benefit from the use of these approaches with similar disenfranchised and unfairly treated populations.

Assessment of recovery status in chronic fatigue syndrome using normative data.

Adamowicz et al. have reviewed criteria previously employed to define recovery in chronic fatigue syndrome (CFS). They suggested such criteria have generally lacked stringency and consistency between studies and recommended future research should require "normalization of symptoms and functioning". Options regarding how "normalization of symptoms and functioning" might be operationalized for CFS cohorts are explored. A diagnosis of CFS excludes many chronic disabling illnesses present in the general population, and CFS cohorts can almost exclusively consist of people of working age; therefore, it is suggested that thresholds for recovery should not be based on population samples which include a significant proportion of sick, disabled or elderly individuals. It is highlighted how a widely used measure in CFS research, the SF-36 physical function subscale, is not normally distributed. This is discussed in relation to how recovery was defined for a large intervention trial, the PACE trial, using a method that assumes a normal distribution. Summary data on population samples are also given, and alternative methods to assess recovery are proposed. The "normalization of symptoms and function" holds promise as a means of defining recovery from CFS at the current time. However, care is required regarding how such requirements are operationalized, otherwise recovery rates may be overstated, and perpetuate the confusion and controversy noted by Adamowicz et al.

Chronic fatigue syndrome from vagus nerve infection: A psychoneuroimmunological hypothesis

Chronic fatigue syndrome (CFS) is an often-debilitating condition of unknown origin. There is a general consensus among CFS researchers that the symptoms seem to reflect an ongoing immune response, perhaps due to viral infection. Thus, most CFS research has focused upon trying to uncover that putative immune system dysfunction or specific pathogenic agent. However, no single causative agent has been found. In this speculative article, I describe a new hypothesis for the etiology of CFS: infection of the vagus nerve. When immune cells of otherwise healthy individuals detect any peripheral infection, they release proinflammatory cytokines. Chemoreceptors of the sensory vagus nerve detect these localized proinflammatory cytokines, and send a signal to the brain to initiate sickness behavior. Sickness behavior is an involuntary response that includes fatigue, fever, myalgia, depression, and other symptoms that overlap with CFS. The vagus nerve infection hypothesis of CFS contends that CFS symptoms are a pathologically exaggerated version of normal sickness behavior that can occur when sensory vagal ganglia or paraganglia are themselves infected with any virus or bacteria. Drawing upon relevant findings from the neuropathic pain literature, I explain how pathogen-activated glial cells can bombard the sensory vagus nerve with proinflammatory cytokines and other neuroexcitatory substances, initiating an exaggerated and intractable sickness behavior signal. According to this hypothesis, any pathogenic infection of the vagus nerve can cause CFS, which resolves the ongoing controversy about finding a single pathogen. The vagus nerve infection hypothesis offers testable hypotheses for researchers, animal models, and specific treatment strategies.

Cognitive impairments associated with CFS and POTS

Chronic fatigue syndrome (CFS) is characterized by fatigue, sleep dysfunction, and cognitive deficits (Fukuda et al., 1994). Research surrounding cognitive functioning among patients with CFS has found difficulty with memory, attention, and information processing. A similar disorder, postural tachycardia syndrome (POTS), is characterized by increased heart rate, fatigue, and mental cloudiness (Raj et al., 2009). Potential implications of cognitive deficits for patients with CFS and/or POTS are discussed, including difficulties with school and/or employment. A few biological theories (i.e., kindling, impairments in the central nervous system, and difficulty with blood flow) have emerged as potential explanations for the cognitive deficits reported in both CFS and POTS Future research should continue to examine possible explanations for cognitive impairments in CFS and POTS, and ultimately use this information to try and reduce cognitive impairments for these patients.

Responses to Exercise Differ for Chronic Fatigue Syndrome Patients with Fibromyalgia

Chronic fatigue syndrome (CFS) and fibromyalgia (FM) are chronic multisymptom illnesses with substantial clinical and diagnostic overlap. We have previously shown that, when controlling for aerobic fitness and accounting for comorbid FM, CFS patients do not exhibit abnormal cardiorespiratory responses during maximal aerobic exercise compared with healthy controls, despite differences in pain and exertion. The purpose of the present study was to examine cardiac and perceptual responses to steady-state submaximal exercise in CFS patients and healthy controls. Twenty-one CFS patients (13 CFS with comorbid FM (CFS + FM)) and 14 controls completed 20 min of submaximal cycling exercise. Impedance cardiography was used to determine cardiac responses during exercise. Systolic blood pressure (SBP), RPE, and leg muscle pain were also measured. Data were analyzed using a doubly multivariate, repeated-measures MANOVA to model the exercise response. There was a significant multivariate time-by-group interaction (P < 0.05). The CFS + FM group exhibited an exercise response characterized by higher stroke index, ventilatory equivalents for oxygen and carbon dioxide and RPE, lower SBP, and similar HR responses compared to controls. The present results extend on our previous work with maximal exercise and show that CFS and CFS + FM differ in their responses to steady-state exercise. These results highlight the importance of accounting for comorbid conditions when conducting CFS research, particularly when examining psychophysiological responses to exercise.

Minimum data elements for research reports on CFS

Chronic fatigue syndrome (CFS) is a debilitating condition that has received increasing attention from researchers in the past decade. However, it has become difficult to compare data collected in different laboratories due to the variability in basic information regarding descriptions of sampling methods, patient characteristics, and clinical assessments. The issue of variability in CFS research was recently highlighted at the NIH's 2011 State of the Knowledge of CFS meeting prompting researchers to consider the critical information that should be included in CFS research reports. To address this problem, we present our consensus on the minimum data elements that should be included in all CFS research reports, along with additional elements that are currently being evaluated in specific research studies that show promise as important patient descriptors for subgrouping of CFS. These recommendations are intended to improve the consistency of reported methods and the interpretability of reported results. Adherence to minimum standards and increased reporting consistency will allow for better comparisons among published CFS articles, provide guidance for future research and foster the generation of knowledge that can directly benefit the patient.

Random Sample

On 23 September, archaeologists and historians from across Europe will reconstruct the evolution of clothing on the catwalk. PHD Comics, the cartoon read by procrastinating grad students everywhere, is coming to life on the big screen: The PHD Movie debuted 22 September at the California Institute of Technology. And this week's numbers quantify funding for chronic fatigue syndrome research and the amount that five common, chronic noncommunicable diseases will cost the world by 2030.

Chronic fatigue syndrome: understanding a complex illness

Chronic fatigue syndrome (CFS) is a debilitating illness that affects many people. It has been marred by controversy, from initial scepticism in the medical community about the existence of the condition itself to continuing disagreements--mainly between some patient advocacy groups on one side, and researchers and physicians on the other--about the name for the illness, its aetiology, its pathophysiology and the effectiveness of the few currently available treatments. The role of the CNS in the disease is central in many of these discussions. Nature Reviews Neuroscience asked four scientists involved in CFS research about their views on the condition, its causes and the future of research aimed at improving our understanding of this chronic illness.

What is XMRV and should we be worried about it?

What is XMRV and should we be worried about it?

A review of the definitional criteria for chronic fatigue syndrome

The research community has for more than three decades tried to unravel the diagnostic mystery that is Chronic Fatigue Syndrome (CFS). This has resulted in considerable amounts of time and money being invested in attempts aimed at establishing the aetiology and pathogenesis of CFS. All of this investment has produced evidence of an interesting variety of endocrine, immune, infectious, muscular and neurological abnormalities in CFS; however, the cause remains elusive. The absence of a known causative agent or diagnostic test for CFS has resulted in the development of a number of CFS case definitions. As such, the main objectives of this paper are to provide a critical review of the similarities and differences between the varying approaches to CFS case definition. The conflicts and controversies that have emerged as a result of the differing definitional criterion for CFS are highlighted and the potential impact on future research is identified. This paper presents a critical review of the most frequently used case definitions in CFS. There are currently five case definitions of CFS; however, the most prominent and widely used of these definitions is the 1994 Centre for Disease Control and Prevention Case Definitions. However, the pre-eminence of this definition over the others has never been substantiated and it has been widely criticized for its lack of specificity. Furthermore, none of the above case definitions have produced evidence to demonstrate their accuracy or precision at defining cases of CFS. A summary description of the symptom profile included in each of the case definitions is provided. The inconsistencies that have emerged in CFS research as a consequence of differing approaches to case definition are also highlighted and discussed.

A comparison of classification methods for predicting Chronic Fatigue Syndrome based on genetic data.

BackgroundIn the studies of genomics, it is essential to select a small number of genes that are more significant than the others for the association studies of disease susceptibility. In this work, our goal was to compare computational tools with and without feature selection for predicting chronic fatigue syndrome (CFS) using genetic factors such as single nucleotide polymorphisms (SNPs).MethodsWe employed the dataset that was original to the previous study by the CDC Chronic Fatigue Syndrome Research Group. To uncover relationships between CFS and SNPs, we applied three classification algorithms including naive Bayes, the support vector machine algorithm, and the C4.5 decision tree algorithm. Furthermore, we utilized feature selection methods to identify a subset of influential SNPs. One was the hybrid feature selection approach combining the chi-squared and information-gain methods. The other was the wrapper-based feature selection method.ResultsThe naive Bayes model with the wrapper-based approach performed maximally among predictive models to infer the disease susceptibility dealing with the complex relationship between CFS and SNPs.ConclusionWe demonstrated that our approach is a promising method to assess the associations between CFS and SNPs.

Causes of extreme fatigue in underperforming athletes - a synthesis of recent hypotheses and reviews

The underperformance syndrome (UPS), previously known as the overtraining syndrome (OTS), has been defined as a persistent decrement in athletic performance capacity despite 2 weeks of relative rest. Clinical research has suggested that cytokines play a key role in fatigue in disease and chronic fatigue syndrome. Furthermore, it has recently been demonstrated that exogenous administration of interleukin-6 (IL-6) increases the sensation of fatigue during exercise. In light of current cytokine and chronic fatigue syndrome research, this article reviews and updates the cytokine theories that attempt to explain the aetiology of the debilitating fatigue experienced in OTS/UPS. Initially, it was proposed that UPS may be caused by excessive cytokine release during and following exercise, causing a chronic inflammatory state and ‘cytokine sickness'. More recently, the hypothesis was extended and it was proposed that time-dependent sensitisation could provide a model through which the aetiology of UPS may be explained. According to this model, the principal abnormal factor in UPS is an intolerance/heightened sensitivity to IL-6 during exercise. South African Journal of Sports Medicine Vol. 18 (4) 2006: pp. 108-114

A Bayesian Approach to Gene–Gene and Gene–Environment Interactions in Chronic Fatigue Syndrome

In the study of genomics, it is essential to address gene-gene and gene-environment interactions for describing the complex traits that involves disease-related mechanisms. In this work, our goal is to detect gene-gene and gene-environment interactions resulting from the analysis of chronic fatigue syndrome patients' genetic and demographic factors including SNPs, age, gender and BMI. We employed the dataset that was original to the previous study by the Centers for Disease Control and Prevention Chronic Fatigue Syndrome Research Group. To investigate gene-gene and gene-environment interactions, we implemented a Bayesian based method for identifying significant interactions between factors. Here, we employed a two-stage Bayesian variable selection methodology based on Markov Chain Monte Carlo approaches. By applying our Bayesian based approach, NR3C1 was found in the significant two-locus gene-gene effect model, as well as in the significant two-factor gene-environment effect model. Furthermore, a significant gene-environment interaction was identified between NR3C1 and gender. These results support the hypothesis that NR3C1 and gender may play a role in biological mechanisms associated with chronic fatigue syndrome. We demonstrated that our Bayesian based approach is a promising method to assess the gene-gene and gene-environment interactions in chronic fatigue syndrome patients by using genetic factors, such as SNPs, and demographic factors such as age, gender and BMI.

Chronic Fatigue Syndrome and the Central Nervous System

An increasing amount of neuroimaging evidence supports the hypothesis that chronic fatigue syndrome patients have structural or functional abnormalities within the brain. Moreover, some neurotrophic factors, neurotransmitters and cytokines have also been evaluated in order to elucidate the mechanism of abnormal neuropsychic findings in chronic fatigue syndrome. In this review, we suggest that the focal point of chronic fatigue syndrome research should be transferred to the central nervous system.

Teaching medical students about medically unexplained illnesses: A preliminary study

Background: This study examined how an interactive seminar focusing on two medically unexplained illnesses, chronic fatigue syndrome (CFS) and fibromyalgia, influenced medical student attitudes toward CFS, a more strongly stigmatized illness. Methods: Forty-five fourth year medical students attended a 90 minute interactive seminar on the management of medically unexplained illnesses that was exemplified with CFS and fibromyalgia. A modified version of the CFS attitudes test was administered immediately before and after the seminar. Results: Pre-seminar assessment revealed neutral to slightly favorable toward CFS. At the end of the seminar, significantly more favorable attitudes were found toward CFS in general (t (42) = 2.77; P < 0.01) and for specific items that focused on (1) supporting more CFS research funding (t (42) = 4.32; P < 0.001; (2) employers providing flexible hours for people with CFS (t (42) = 3.52, P < 0.01); and (3) viewing CFS as not primarily a psychological disorder (t (42) = 2.87, P < 0.01). Thus, a relatively brief exposure to factual information on specific medically unexplained illnesses was associated with more favorable attitudes toward CFS in fourth year medical students. Conclusion: This type of instruction may lead to potentially more receptive professional attitudes toward providing care to these underserved patients.