Fatigue: Biomedicine, Health & Behavior - Volume 3, Issue 2, 2015

Titles and abstracts for the journal, Fatigue: Biomedicine, Health & Behavior, Volume 3, Issue 2, 2015.

Volume 4, Issue 2, 2016

• Institute of medicine report on chronic fatigue syndrome: case definition issues and future directions., Editorial by Fred Friedberg
• Comparing and contrasting consensus versus empirical domains

  Abstract - Background: Since the publication of the CFS case definition, there have been a number of other criteria proposed including the Canadian Consensus Criteria and the Myalgic Encephalomyelitis: International Consensus Criteria. Purpose: The current study compared these domains that were developed through consensus methods to one obtained through more empirical approaches using factor analysis. Methods: Using data mining, we compared and contrasted fundamental features of consensus-based criteria versus empirical latent factors. In general, these approaches found the domain of fatigue/post-exertional malaise as best differentiating patients from controls. Results: Findings indicated that the Fukuda et al. criteria had the worst sensitivity and specificity. Conclusions: These outcomes might help both theorists and researchers better determine which fundamental domains to be used for the case definition.

• Findings from a clinical and laboratory database developed for discovery of pathogenic mechanisms in myalgic encephalomyelitis/chronic fatigue syndrome

  Abstract - Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, chronic illness that is often disabling. This paper introduces the Chronic Fatigue Initiative, which conducted a large multi-center study to more fully characterize ME/CFS and ultimately to describe and understand the underlying mechanisms and pathogenesis of this illness. Methods: A total of 203 patients with ME/CFS (cases) and 202 matched healthy controls (HCs) were enrolled from 5 geographically different expert clinical sites to create a well-characterized population linked to a national biorepository. ME/CFS subjects were compared to a one-to-one matched HC population for analyses of symptoms and illness severity. Cases were further evaluated for frequency and severity of symptoms and symptom clusters, and the effects of illness duration and acute vs. gradual onset. Results: This study collected more than 4000 pieces of data from each subject in the study. Marked impairment was demonstrated for cases vs. controls. Symptoms of fatigue were identified, but also, nearly as frequent and severe, were symptoms of cognitive dysfunction, inflammation, pain and autonomic dysfunction. Potential subgrouping strategies were suggested by these identified symptom clusters: sleep, neurocognitive, autonomic, inflammatory, neuroinflammatory, gastrointestinal and endocrine symptoms. Conclusions: Clearly, ME/CFS is not simply a state of chronic fatigue. These data indicate that fatigue severity is matched by cognitive, autonomic, pain, inflammatory and neuroinflammatory symptoms as the predominant clinical features. These findings may assist in the clarification and validation of case definitions. In addition, the data can aid clinicians in recognizing and understanding the overall illness presentation. Framing ME/CFS as a multisystem disorder may assist in developing therapies targeting the multifaceted domains of illness.

• Improving academic success for students with myalgic encephalomyelitis/chronic fatigue syndrome

  Abstract - Students with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) often struggle to achieve academic success not only due to symptom interference, but also because educators may lack an understanding of the cognitive and learning deficits that accompany the illness. Traditional education research may lead teachers to employ less-than-effective strategies and accommodations to support students with this illness. Recent findings from neurocognitive research provide greater insight into the cognitive deficits that accompany ME/CFS and also suggest more effective classroom strategies. The purpose of this paper is to outline the cognitive and classroom challenges faced by students with ME/CFS, and to provide examples of sensible accommodations for those problems. These accommodations are intended to improve the academic success of students with this debilitating illness.

• Exercise and caffeine improve sustained attention following fatigue independent of fitness status.

  Abstract - Background: Exercise improves cognition, but whether fitness status and caffeine modulate this effect remains unclear. Purpose: To determine if sustained attention is improved following exercise with and without caffeine in endurance-trained vs. sedentary adults. Methods: A continuous performance task (CPT), that is, a 20 min measure of sustained attention to assess accuracy and precision, was used to induce mental fatigue. Following the 20 min CPT, trained (n = 12) and sedentary (n = 12) participants completed either 30-min rest or 30-min moderate-intensity cycling below lactate threshold. Exercise trials were completed with placebo and caffeine (3 mg/kg) followed by cycling to volitional fatigue. Results: Exercise, as compared to rest, improved (p < .05) accuracy and precision after a mentally fatiguing task (CPT) and was not different between endurance-trained and sedentary groups. During the CPT, accuracy and precision declined (p < .05) with placebo, but both were maintained with caffeine following both exercise and cycling to volitional fatigue. Mental energy declined (p < .05) after the CPT with placebo but not caffeine. Cycling to volitional fatigue resulted in lower mental energy/greater mental fatigue as compared to baseline and following moderate intensity exercise, for both caffeine and placebo (p < .05). Conclusions: Exercise improved sustained attention following a mentally fatiguing attentional task independent of fitness status; and, when coupled with caffeine, provided greater benefit on the attentional task for accuracy, precision, and mental energy. Although caffeine's beneficial effect on sustained attention persisted after cycling to volitional fatigue, it did not prevent a decline in mental energy/increase in mental fatigue.

• Brain-derived neurotrophic factor concentration may not be depressed in chronic fatigue syndrome.

  Abstract - Due to its effect on the central nervous system, brain-derived neurotrophic factor (BDNF) has been hypothesized to be involved in a number of neurodegenerative and psychiatric disorders. Recently, BDNF was also reported to be significantly lower in patients with chronic fatigue syndrome (CFS) and multiple sclerosis patients, than in healthy controls. We tried to repeat this observation in 25 patients with CFS matched to 25 healthy controls and 11 patients with systemic lupus erythematosus. Our study did not find significant differences in BDNF between groups. Furthermore, we investigated the relationship between BDNF levels and fatigue within CFS sufferers using the fatigue severity score and found no correlation between the two measures. Our findings act as a caution that results should be replicated in independent laboratories for validation, and we would welcome more research in this area.

See also

• Fatigue: Biomedicine, Health & Behavior for other Issues

Canadian Consensus Criteria (CCC) - A set of diagnostic criteria used to diagnose ME/CFS, developed by a group of practicing ME/CFS clinicians in 2003. The CCC is often considered to be the most complex criteria, but possibly the most accurate, with the lowest number of patients meeting the criteria. Led to the development of the International Consensus Criteria (ICC) in 2011.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.

post-exertional malaise (PEM) - A notable exacerbation of symptoms brought on by small physical or cognitive exertions. PEM may be referred to as a "crash" or "collapse" and can last for days or weeks. Symptoms can include cognitive impairments, muscle pain, trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, and others.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.

chronic fatigue (CF) - Persistent and abnormal fatigue is a symptom, not an illness. It may be caused by depression, multiple sclerosis, fibromyalgia, chronic fatigue syndrome or many other illnesses. The term "chronic fatigue" should never be confused with the disease chronic fatigue syndrome.

cognition Thought processes, including attention, reasoning, and memory.

cognition Thought processes, including attention, reasoning, and memory.

accuracy The "closeness of an observation to the true clinical state". With respect to diagnostic tests, "accuracy" means how specific and sensitive the test is.

central nervous system (CNS) - One of the two parts of the human nervous system, the other part being the peripheral nervous system. The central nervous system consists of the brain and spinal cord, while the peripheral nervous system consists of nerves that travel from the central nervous system into the various organs and tissues of the body.

National Academy of Medicine (NAM) - An American non-profit, non-governmental organization which provides expert advice to governmental agencies on issues relating to biomedical science, medicine and health. Formerly known as the Institute of Medicine (IOM).