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PubMed2000

Development and validation of the cancer fatigue scale: a brief, three-dimensional, self-rating scale for assessment of fatigue in cancer patients.

We herein describe the development and validation of the Cancer Fatigue Scale (CFS) for assessment of fatigue in cancer patients. We designed this scale specifically to reflect the nature of fatigue experienced by cancer patients, by using factor analysis; the CFS is a 15-item scale composed of 3 subscales (physical, affective, and cognitive subscales). Three hundred seven cancer patients participated in the validation phase. Construct validity, confirmed by repeating factor analysis, was good. Convergent validity, confirmed by a correlation between CFS and a visual analogue scale for fatigue, was also shown to be good (r = 0.67, P < 0.001). The CFS had good stability (average test-retest reliability r = 0.69, P < 0.001) and good internal consistency (Cronbach's alpha coefficient for all 15 items = 0.88). The present study indicates that the CFS is a brief, valid, and feasible measure of fatigue for use with cancer patients.

Adolescent↗

PubMed1998

EMG fatigue patterns accompanying isometric fatiguing knee-extensions are different in mono- and bi-articular muscles.

OBJECTIVES AND METHODS: Isometric, fatiguing knee-extensions at 30%, 50% and 70% maximum voluntary contraction (MVC) were performed by 18 healthy human subjects. Surface electromyographic (SEMG) activity was recorded from the mono-articular vastus medialis (VM) and vastus lateralis (VL) muscles, and the bi-articular rectus femoris muscle (RF). To make the bi-articular muscle work under (1) constant and (2) similar working conditions as the two mono-articulars do, the hip was fixed in a flexed position. The root mean square (RMS) SEMG recorded during fatigue was standardized to the respective values of MVC. The mean coefficients of regression of the RMS and median frequency (MF) changes were then analyzed by multivariate analysis of variance. RESULTS: The load effect upon the muscle fatigue changes, as measured by increase in RMS EMG, differed between the bi-articular muscle and the two mono-articulars, in that the parameter dropped with maximum load for the bi-articular, whilst it remained stable or even increased for the mono-articulars. This might suggest that the mono- and bi-articular muscles have different roles in fatigue tasks where the bi-articulars function purely as mono-articulars. By contrast, such a clear dichotomy between the bi-articular RF and the two mono-articulars, VM and VL, was lacking for the fatigue parameter of MF. CONCLUSIONS: As these findings were confined to the changes in RMS EMG, different neuronal coding mechanisms for the mono- and bi-articular muscles in the central nervous system may be inferred.

Adult↗

PubMedDate not supplied

Cancer-related fatigue. Suffering a different fatigue.

PURPOSE: The purpose of this naturalistic inquiry was to understand, from the patient's perspective, the differences between cancer-related fatigue (CRF) and "typical" fatigue and to describe its impact on their lives. DESCRIPTION OF STUDY: The sample consisted of 17 adult patients with cancer who agreed to participate, yielding 23 in-depth audio-taped interviews. Participants included inpatients and outpatients from a dedicated cancer center and a Veterans Affairs Hospital. Symbolic interactionism was the framework used for the interviews to understand how individuals and groups construct and discover the meaning of events. Transcribed data were coded by distress category to classify the textual information and to reduce the text to more relevant and manageable bits of data. Five to 10 representative excerpts from each coding category were chosen and were coded independently by a second coder to evaluate intercoder reliability. RESULTS: CRF was found to be more rapid in onset, more energy draining, more intense, longer lasting, more severe, and more unrelenting when compared with "typical" fatigue. CRF caused distress in the physical, social, spiritual, psychological, and cognitive domains of the participants' lives. All participants agreed that CRF was different than the typical fatigue of everyday life. CLINICAL IMPLICATIONS: This study's findings indicate that because of this different fatigue, CRF, participants did not just experience the symptom, but they suffered with it. The current oncology literature and texts do not portray the morbidity of the CRF experience as described by the participants in this study. These data can be used as part of an experiential teaching guide to assist healthcare students and practitioners in understanding the CRF experience. This increased awareness will afford clinicians a better foundation for implementing management strategies. A CRF distress instrument is in development based on these data.

Activities of Daily Living↗

PubMed2001

Dimensions of fatigue during radiotherapy--an application of the Swedish Occupational Fatigue Inventory (SOFI) on cancer patients.

The aims of this study were primarily to evaluate the applicability of the Swedish Occupational Fatigue Inventory (SOFI) on cancer patients, secondly to describe the development of fatigue in patients, receiving full dose radiotherapy with a curative intent. A questionnaire was completed by 81 cancer patients at four occasions; before treatment. during the last week of treatment. 1 and 3 months, respectively, after treatment. The fatigue increased significantly at the end of treatment, as compared to pretreatment, and decreased after treatment. The highest fatigue ratings concerned lack of energy, lack of motivation and sleepiness. The five SOFI-dimensions explained more than half of the variance in the overall rating of fatigue, and the internal consistency of the dimensions were good. However, the ratings were on the lower part of the scale and the dimensions correlated more than expected. Thus, the relevance of the SOFI for use also among patients is only partially supported, and studies with larger samples are needed for further testing of the inventory.

Adult↗

PubMedDate not supplied

Bromocriptine in the treatment of post-polio fatigue: a pilot study with implications for the pathophysiology of fatigue.

Fatigue is the most commonly reported and most disabling of all post-polio sequelae (PPS). Bromocriptine mesylate (Parlodel) was employed in a placebo-controlled trial in five survivors of paralytic polio who continued to report moderate to severe daily fatigue after complying with the conservative treatments prescribed for PPS. Placebo was given for 4 wk followed by increasing doses of bromocriptine mesylate, administered at 12:00 pm for 28 days, which reached a total dose of 12.5 mg/day. Three subjects reported marked symptom improvement on bromocriptine but not on placebo. Their reported difficulty with attention, concentration, word finding, mind wandering, memory, thinking clearly, and fatigue on awakening was significantly negatively correlated with days on bromocriptine but not with days on placebo. Before the drug trial began, responders had clinically impaired performance on neuropsychologic tests of attention and information processing speed, more than twice as many hyperintensities on magnetic resonance imaging of the brain, abnormally low fasting adrenocorticotropic hormone levels, and nearly double the mean plasma prolactin level compared with nonresponders. The implications of these findings for the pathophysiology of fatigue are discussed. A double-blind, placebo-controlled, multicenter study will be needed to confirm bromocriptine's efficacy in treating attentionally and neurophysiologically impaired polio survivors whose severe and disabling fatigue does not respond to conservative therapies.

Adrenocorticotropic Hormone↗

PubMed1987

Force-velocity properties of fatigue-resistant units in cat fast-twitch muscle after fatigue.

The isometric and force-velocity properties of an identified and uniform population of fast-twitch, fatigue-resistant (FR) fibers within the flexor digitorum longus (FDL) muscle were investigated before, immediately after, and during recovery from a fatiguing repetitive isometric stimulus regime (40 Hz for 330 ms every s for 180 s) in the anesthetized cat. It was necessary to determine the smallest fraction of muscle that had the same force-velocity properties as the whole muscle. This was approximately 15% for FDL; if the fraction was less, the maximum speed of shortening was depressed and the a/Po value increased. Motor units were enlarged by partial denervation of the muscle, causing the intact motoneurons to sprout and incorporate more muscle fibers; FR units showed the greatest increase. Immediately after the fatigue regime, maximum isometric tetanic tension declined to 67% but subsequently recovered to 90% of the control value by the end of the 60-min recovery period. Maximum speed of shortening dropped to 71% of the control but after 30 min had recovered and did not differ significantly from control values. It is concluded that the capacity for recovery from fatigue is greater for FR units than for a whole muscle, which also contains fast-fatiguable units, and that the mechanisms involved in the recovery of the maximum isometric tension and maximum speed of shortening are independently regulated.

Animals↗

PubMed2006

Fatigue Intervention by Nurses Evaluation--the FINE Trial. A randomised controlled trial of nurse led self-help treatment for patients in primary care with chronic fatigue syndrome: study protocol. [ISRCTN74156610].

BACKGROUND: Chronic fatigue syndrome, also known as ME (CFS/ME), is a condition characterised primarily by severe, disabling fatigue, of unknown origin, which has a poor prognosis and serious personal and economic consequences. Evidence for the effectiveness of any treatment for CFS/ME in primary care, where most patients are seen, is sparse. Recently, a brief, pragmatic treatment for CFS/ME, based on a physiological dysregulation model of the condition, was shown to be successful in improving fatigue and physical functioning in patients in secondary care. The treatment involves providing patients with a readily understandable explanation of their symptoms, from which flows the rationale for a graded rehabilitative plan, developed collaboratively with the therapist. The present trial will test the effectiveness and cost-effectiveness of pragmatic rehabilitation when delivered by specially trained general nurses in primary care. We selected a client-centred counselling intervention, called supportive listening, as a comparison treatment. Counselling has been shown to be as effective as cognitive behaviour therapy for treating fatigue in primary care, is more readily available, and controls for supportive therapist contact time. Our control condition is treatment as usual by the general practitioner (GP). METHODS AND DESIGN: This study protocol describes the design of an ongoing, single-blind, pragmatic randomized controlled trial of a brief (18 week) self-help treatment, pragmatic rehabilitation, delivered by specially trained nurse-therapists in patients' homes, compared with nurse-therapist delivered supportive listening and treatment as usual by the GP. An economic evaluation, taking a societal viewpoint, is being carried out alongside the clinical trial. Three adult general nurses were trained over a six month period to deliver the two interventions. Patients aged over 18 and fulfilling the Oxford criteria for CFS are assessed at baseline, after the intervention, and again one year later. Primary outcomes are self-reported physical functioning and fatigue at one year, and will be analysed on an intention-to-treat basis. A qualitative study will examine the interventions' mechanisms of change, and also GPs' drivers and barriers towards referral.

Clinical Protocols↗

PubMed2004

Measuring fatigue in sarcoidosis: the Fatigue Assessment Scale (FAS).

Fatigue is a major problem in a wide range of diseases including sarcoidosis. However, there is no standard measure for assessing fatigue. Therefore, the aim of the present study was to evaluate the usefulness of the Fatigue Assessment Scale (FAS) in two samples of sarcoidosis patients. Sample 1 included 1 046 members of the Dutch Sarcoidosis Society and Sample 2 consisted of 80 sarcoidosis patients of the outpatient clinic of the Sarcoidosis Management Centre Maastricht, the Netherlands. All patients completed the FAS as well as the 'energy and fatigue' subscale of the WHOQOL-100. Additionally, the participants of Sample 1 filled in the Beck Depression Inventory (BDI). In addition, 241 patients of Sample 1 completed the FAS for the second time after a one-week interval. The FAS appeared to be a unidimensional scale. The content validity, construct validity and internal consistency of the FAS were good. The test - retest reliability was.89. Four FAS items appeared to have a gender bias: three items were uniformly biased and one item non-uniformly biased. Correction for gender bias in the calculation of the FAS total score is not indicated. In conclusion, the FAS is a promising measure for assessing fatigue in sarcoidosis patients.

Adolescent↗

PubMed1994

The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group.

The complexities of the chronic fatigue syndrome and the methodologic problems associated with its study indicate the need for a comprehensive, systematic, and integrated approach to the evaluation, classification, and study of persons with this condition and other fatiguing illnesses. We propose a conceptual framework and a set of guidelines that provide such an approach. Our guidelines include recommendations for the clinical evaluation of fatigued persons, a revised case definition of the chronic fatigue syndrome, and a strategy for subgrouping fatigued persons in formal investigations.

Fatigue Syndrome, Chronic↗

PubMed2000

Fatigue characterization of a hydroxyapatite-reinforced polyethylene composite. I. Uniaxial fatigue.

The fatigue behavior of 40 volume % hydroxyapatite-reinforced polyethylene composite (HAPEXtrade mark) at 37 degrees C in saline was determined. S-N curves for this material, both in fully reversed axial tension-compression and fully reversed torsion, have been established. In tension, the cycles to failure ranged from 1000 cycles at 13 MPa to more than 1 million cycles at 4.4 MPa while in torsion they ranged from 100 cycles at 14.4 MPa to more than 1 million cycles at 4.8 MPa. Changes in strain range, tangent modulus, and cyclic energy dissipated during fatigue loading also were examined. Torsional fatigue was found to be considerably more damaging than axial fatigue. The fatigue damage accumulation process occurring in the composite was monitored by observing the reduction in modulus and the increase in energy dissipated.

Biocompatible Materials↗

PubMed2003

Unified risk analysis of fatigue failure in ductile alloy components during all three stages of fatigue crack evolution process.

Statistical fatigue life of a ductile alloy specimen is traditionally divided into three stages, namely, crack nucleation, small crack growth, and large crack growth. Crack nucleation and small crack growth show a wide variation and hence a big spread on cycles versus crack length graph. Relatively, large crack growth shows a lesser variation. Therefore, different models are fitted to the different stages of the fatigue evolution process, thus treating different stages as different phenomena. With these independent models, it is impossible to predict one phenomenon based on the information available about the other phenomenon. Experimentally, it is easier to carry out crack length measurements of large cracks compared to nucleating cracks and small cracks. Thus, it is easier to collect statistical data for large crack growth compared to the painstaking effort it would take to collect statistical data for crack nucleation and small crack growth. This article presents a fracture mechanics-based stochastic model of fatigue crack growth in ductile alloys that are commonly encountered in mechanical structures and machine components. The model has been validated by Ray (1998) for crack propagation by various statistical fatigue data. Based on the model, this article proposes a technique to predict statistical information of fatigue crack nucleation and small crack growth properties that uses the statistical properties of large crack growth under constant amplitude stress excitation. The statistical properties of large crack growth under constant amplitude stress excitation can be obtained via experiments.

Journal Article↗

PubMed1995

Strain-based fatigue analysis of wheelchairs on a double roller fatigue machine.

Results are presented from an experimental program that recorded the outputs of strain gages mounted on two wheelchair frames (one manual, one power) as the wheelchairs were run on a double roller fatigue machine. Rectangular strain gage rosettes were attached to the frames near the cross tube center pin and on the side frame behind a front caster. Thirty data sets were recorded from each rosette on each wheelchair frame. The fatigue test machine and test protocol were in substantial conformance with the recently published ANSI/RESNA Standard for wheelchair fatigue testing. Two analyses have been performed on the recorded strain data. The von Mises stress histories were computed from the strain data and show that peak stresses are frequently twice the mean value. Also, estimates of the number of fatigue machine cycles to failure have been made using a strain-based fatigue analysis. These data will provide wheelchair designers with useful data to incorporate into their design process.

Mathematics↗

PubMed1996

Viral serologies in patients with chronic fatigue and chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is an illness characterized by disabling fatigue associated with complaints of fevers, sore throat, myalgia, lymphadenopathy, sleep disturbances, neurocognitive difficulties, and depression. A striking feature of CFS is its sudden onset following an acute, presumably viral, illness and the subsequent recurrent "flu-like" symptoms. It has been speculated that both CFS and debilitating chronic fatigue (CF) that does not meet strict criteria for CFS may be the direct or indirect result of viral infections. We therefore tested 548 chronically fatigued patients who underwent a comprehensive medical and psychiatric evaluation for antibodies to 13 viruses. Our objectives were to compare the seroprevalence and/or geometric mean titer (GMT) of antibodies to herpes simplex virus 1 and 2, rubella, adenovirus, human herpesvirus 6, Epstein-Barr virus, cytomegalovirus, and Cox-sackie B virus, types 1-6 in patients with CF to healthy control subjects. Other goals were to determine if greater rates of seropositivity or higher GMTs occurred among subsets of patients with CFS, fibromyalgia, psychiatric disorders, a self-reported illness onset with a viral syndrome, and a documented temperature > 37 degrees C on physical examination. Differences in the seroprevalence or GMTs of antibodies to 13 viruses were not consistently found in those with CF compared with control subjects, or in any subsets of patients including those with CFS, an acute onset of illness, or a documented fever. These particular viral serologies were not useful in evaluating patients presenting with CF.

Adenoviruses, Human↗

PubMedDate not supplied

An epidemiologic study of fatigue with relevance for the chronic fatigue syndrome.

We surveyed households in four rural Michigan communities to confirm a reported cluster of cases resembling chronic fatigue syndrome (CFS) and to study the epidemiology of fatigue in a rural area. Data were collected from 1698 households. We did not confirm the reported cluster. The prevalence of households containing at least one fatigued person was similar between communities thought to harbor the cluster and communities selected for comparison. Symptoms and features of generic forms of fatigue were very similar to those often attributed to CFS.

Adolescent↗

PubMed2002

Cognitive functioning in chronic fatigue syndrome and the role of depression, anxiety, and fatigue.

OBJECTIVE: This study was designed to investigate the role of depression, anxiety, and fatigue in Chronic Fatigue Syndrome (CFS) sufferers' objective and subjective cognitive performance. METHODS: Twenty-three CFS sufferers and 23 healthy control participants were compared on objective and subjective assessments of cognitive performance. Depression, anxiety, and fatigue were also evaluated. RESULTS: CFS sufferers did not demonstrate any impairment in objective cognitive functioning compared to the control group, and objective performance was not related to their higher levels of depression or their level of fatigue. Depression scores only accounted for a small amount of the variance in CFS sufferers' lower subjective assessment of their cognitive performance compared to control participants. There were no differences between the groups on anxiety scores. CONCLUSION: The results are discussed in terms of the heterogeneity of the CFS population and the complex interaction of symptomatological factors that characterise CFS.

Adolescent↗

PubMed2003

Differences between patients with chronic fatigue syndrome and with chronic fatigue at an infectious disease clinic in Stockholm, Sweden.

Background data were collected from patients presenting with fatigue at the clinic of infectious diseases at Huddinge University Hospital, Stockholm. The main purpose was to look for differences as to demographic and functional status for patients fulfilling criteria for chronic fatigue syndrome (CFS) and chronic fatigue (CF). A cross-sectional questionnaire survey was performed using a variety of instruments. A thorough medical investigation was performed. No difference was found as to social situation, occupation and illness attributions for patients in the two categories. Patients with CFS reported in general a higher degree of 'sickness' with more self-reported somatic symptoms, more self-reported functional impairment and more absence from work. A higher degree of psychiatric comorbidity was observed in CF than in CFS patients. A majority of CFS patients (80%) had an acute infectious onset compared to 43% in the CF group. Presently used criteria might, according to findings presented here, define two different patient categories in a population characterized by severe, prolonged fatigue. Because CFS patients (compared to patients with CF) have more somatic symptoms, more often report an infectious, sudden onset and have less psychiatric comorbidity, and CF patients seem to have more of an emotional, burn-out-like component one could speculate about the existence of different pathogenetic backgrounds behind the two diagnoses.

Adolescent↗

PubMed1993

Exercise performance and fatiguability in patients with chronic fatigue syndrome.

To examine the role of delay in recovery of peripheral muscle function following exercise in the fatigue experienced by patients with the chronic fatigue syndrome (CFS) and to examine the influence of effort perception in limiting exercise performance in these patients, a study was carried out on a group of twelve patients with chronic fatigue syndrome and 12 sex and age-matched sedentary control subjects. Symptom limited incremental cycle exercise tests including measurements of perceived exertion were performed followed by examination of the contractile properties of the quadriceps muscle group for up to 48 hours. Muscle function was assessed by percutaneous electrical stimulation and maximum voluntary contractions. Muscle function at rest and during recovery was normal in CFS patients as assessed by maximum isometric voluntary contraction, 20:50 Hz tetanic force ratio and maximum relaxation rate. Exercise duration and the relationship between heart rate and work rate during exercise were similar in both groups. CFS patients had higher perceived exertion scores in relation to heart rate during exercise representing a reduced effort sensation threshold of 3.2 units on an unmodified Borg scale in CFS patients. Patients with chronic fatigue syndrome show normal muscle physiology before and after exercise. Raised perceived exertion scores during exercise suggest that central factors are limiting exercise capacity in these patients.

Adolescent↗

PubMed2006

Assessing fatigue in persons with cancer: further validation of the Wu Cancer Fatigue Scale.

Cancer-related fatigue (CRF) is a significant clinical symptom. Effective assessment of CRF attributes from the patients' perspective is essential. This study tested the psychometric properties of the Wu Cancer Fatigue Scale (WCFS). A total of 172 outpatients with breast cancer, who were at various stages and on various chemotherapy regimens, and were undergoing treatment at one of three cancer clinics in a Midwest metropolitan area, participated in this study. The participants were instructed to complete four instruments in the following order: the 16-item WCFS, Schwartz Cancer Fatigue Scale (SCFS), Geriatric Depression Scale (GDS), and Cancer-Related Fatigue Distress Scale (CRFDS). Structural equation modeling (LISREL 8.54) supported the one-factor measurement model with nine items remaining. Nonsignificant Satorra-Bentler Scaled Chi-square (27)=32.52, P=0.21, standardized root mean square residual=0.032, nonnormal fit index=0.97, comparative fit index=0.98, and incremental fit index=0.98 indicated a good model fit. Convergent validity with the SCFS was 0.78, concurrent validity with the GDS was 0.60, and predictive validity with the CRFDS was 0.73. Internal consistency reliability was alpha=0.91 for the nine-item scale. The revised WCFS is a reliable and valid instrument that aims to measure the subjective characteristics of CRF from the patients' perspective. It may prove useful in both clinical and research settings.

Adult↗