Fatigue: Biomedicine, Health & Behavior - Volume 1, Issue 1-2, 2013

Volume 1, Issue 1-2, 2013

 * Welcome to our inaugural issue! Editorial, by Fred Friedberg, First Page Preview
 * Scientific status of fatigue and pain. Publishing and professional activities: 2002–2011 "Abstract - Background: Clinicians and researchers often deal with fatigue and pain in patients who are ill, and in healthy individuals. Purpose: To identify fatigue and pain publishing trends and professional activities over a recent decade in order to assess the scientific status of these domains. Methods: Peer review citations and professional activities for fatigue as compared to pain were tabulated for the decade, 2002–2011. Results: For the decade, fatigue represented 15% of citations, and pain, 85%. Annual publication frequencies fit an exponential model for fatigue (R squared=0.97; p<0.0001) and a linear model for pain (R squared=0.94; p<0.0001). The most common fatigue research categories were: “non-disease” (38%; e.g., fatigue in exercise, workers, healthy populations), medically unexplained fatigue (18.8%; primarily chronic fatigue syndrome/myalgic encephalomyelitis [CFS/ME]), and cancer fatigue (8%). No overarching theory of fatigue was identified. By comparison, the central sensitization model of pain has gained cross-disciplinary recognition. Although a scientific discipline of pain was evident, the field of fatigue studies lacks many of the elements (e.g., texts, accreditation programs) necessary for an established discipline. Conclusions: Although fewer articles were found for fatigue in comparison to pain, publishing rates for both domains increased by about 90% over the decade. The literature has begun to identify the importance of the symptom of fatigue."
 * Fatigue and circadian activity rhythms in breast cancer patients before and after chemotherapy: a controlled study "Abstract - Background: Breast cancer (BC) patients often experience cancer-related fatigue (CRF) before, during, and after their chemotherapy. Circadian rhythms are 24-hour cycles of behavior and physiology that are generated by internal pacemakers and entrained by zeitgebers (e.g., light). A few studies have suggested a relationship between fatigue and circadian rhythms in some clinical populations. Methods: One hundred and forty-eight women diagnosed with stage I–III breast cancer and scheduled to receive at least four cycles of adjuvant or neoadjuvant chemotherapy, and 61 controls (cancer-free healthy women) participated in this study. Data were collected before (Baseline) and after four cycles of chemotherapy (Cycle-4). Fatigue was assessed with the Short Form of Multidimensional Fatigue Symptom Inventory (MFSI–SF); circadian activity rhythm (CAR) was recorded with wrist actigraphy (six parameters included: amplitude, acrophase, mesor, up-mesor, down-mesor and F-statistic). A mixed model analysis was used to examine changes in fatigue and CAR parameters compared to controls, and to examine the longitudinal relationship between fatigue and CAR parameters in BC patients. Results: More severe CRF (total and subscale scores) and disrupted CAR (amplitude, mesor and F-statistic) were observed in BC patients compared to controls at both Baseline and Cycle-4 (all p's < 0.05); BC patients also experienced more fatigue and decreased amplitude and mesor, as well as delayed up-mesor time at Cycle-4 compared to Baseline (all p's < 0.05). The increased total MFSI–SF scores were significantly associated with decreased amplitude, mesor and F-statistic (all p's < 0.006). Conclusion: CRF exists and CAR is disrupted even before the start of chemotherapy. The significant relationship between CRF and CAR indicate possible underlying connections. Re-entraining the disturbed CAR using effective interventions such as bright light therapy might also improve CRF."
 * Energy conservation/envelope theory interventions "Abstract - Objectives: Treatment approaches for patients with chronic fatigue syndrome (CFS), Myalgic Encephalomyelitis (ME) and Myalgic Encephalomyelitis/chronic fatigue syndrome (ME/CFS) have been controversial. This paper provides the theoretical and conceptual background for the Energy Envelope Theory to assist patients and reviews evidence of its treatment efficacy. Methods: Over a 15-year period, efforts were directed to develop a non-pharmacologic intervention that endeavored to help patients to self-monitor and self-regulate energy expenditures and learn to pace activities and stay within their energy envelope. Conclusions: Studies show that the energy envelope approach, which involves rehabilitation methods, helps patients pace activities and manage symptoms and can significantly improve their quality of life."
 * Fatigue in older populations "Abstract - The aim of this paper is to give an overview of research on general fatigue, mobility-related fatigue, and fatigability in older adults, with a focus on fatigue as an early indicator of the aging process. Fatigue is a strong predictor of functional limitations, disability, mortality, and other adverse outcomes in young-old and old-old populations, in men and women, and in different geographic localities. Several biological, physiological, and social explanations are proposed: fatigue may be seen not only as a self-reported indicator of frailty, defined as a physiologic state of increased vulnerability to stressors which results from decreased physiologic reserves and even dysregulation of multiple physiologic systems, but this state may be accelerated by the cumulative impact of social, mental, and biological factors throughout life. Fatigue in older adults is the result of multiple potentially modifiable factors, of which some may be fully treated or at least alleviated, thus slowing down the speed of the aging process."
 * Fatigue, sleep, and stress: dynamic relationships in fibromyalgia "Abstract - Background: Fibromyalgia (FMS) is a chronic pain syndrome characterized by fatigue and non-restorative sleep. Over 75% of individuals with FMS complain of fatigue and poor sleep. Purpose: The primary aim of this study was to compare 25 women with and 25 women without FMS, on fatigue; autonomic nervous system activity; perceived stress; sleep quality; and immune function. All participants complained of poor sleep, and had been referred to a sleep center for evaluation. The secondary aim was to explore the relationships among those variables within each group and compare those relationships between groups. Methods: A single stage cross-sectional design was used. Results: The FMS group reported greater fatigue, worse sleep, and more autonomic symptoms than the non-FMS group; they evidenced higher tumor necrosis factor alpha (TNF-α) levels. Non-FMS participants with obstructive sleep apnea (OSA) had higher interleukin 1-beta (IL-1β) values than the FMS group. In the FMS group, fatigue was positively correlated with stress, autonomic symptoms, and TNF-α; stress was positively correlated with autonomic symptoms; apnea–hypopnea index (AHI) was negatively correlated with IL-1β levels and total arousals. In the non-FMS group, fatigue was positively correlated with sleep quality; both variables were positively correlated with IL-1β. IL-1β was also positively correlated with TNF-α. Conclusions: Variables that were correlated in the FMS group differed from those in the non-FMS group, except for the correlation of total arousals with AHI."
 * Fatigue in the workplace: causes and countermeasures "Abstract - Many workers are exposed to fatigue risk that they would rarely encounter outside their job. This paper discusses the current state of occupational fatigue research, providing a snapshot of the evidence on its causes and an overview of occupational health and safety approaches to its management. Frameworks for managing other hazards and risk in workplaces are applicable to occupational fatigue and have spurred the development of new regulatory approaches for fatigue. Although our understanding of the causes of occupational fatigue is improving, there is as yet little research evaluating fatigue risk management systems and countermeasures."
 * Work schedules, sleep, fatigue, and accidents in the US railroad industry "Abstract - Objective: The objective of this report is to provide a comprehensive description of fatigue in US railroad workers employed in safety-sensitive positions. Methods: Five survey studies were conducted between 2006 and 2011 on maintenance of way employees, signalmen, dispatchers, train & engine (T&E) employees, and T&E employees engaged in passenger service. These studies were reanalyzed and compared with regard to work schedules and sleep patterns. Fatigue exposure was determined by analysis of work schedules and sleep patterns with a fatigue model, the Fatigue Avoidance Scheduling Tool (FAST). Results: Twelve different schedules of work exist in the five groups of railroad employees. Work schedules largely determine sleep patterns, which, in turn, determine fatigue exposure. T&E crews and dispatchers have the highest fatigue exposure, but these two groups have considerably less fatigue exposure than T&E crews who were involved in accidents. Passenger service T&E employees have the least fatigue exposure, even though the distribution of work time is highly similar to that of T&E employees. This difference in fatigue exposure may be due to the greater predictability of work for the passenger service T&E. Human factor accident probability and the cost of human factor accidents increase with fatigue exposure. The risk (probability × cost) of a human factor accident increases exponentially with fatigue exposure. Conclusions: A methodology has been developed for studying the work schedules and sleep patterns of railroad workers. This methodology allows for the collection of data which makes it possible to identify differences in sleep patterns as a function of both work group and work schedule. Future work on fatigue in occupational groups should focus on similar methods to expand our knowledge of the role of work schedules on sleep, fatigue, and accident risk."