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PubMed2004

Fatigue and primary biliary cirrhosis: association of globus pallidus magnetisation transfer ratio measurements with fatigue severity and blood manganese levels.

BACKGROUND AND AIM: Fatigue is the commonest symptom in primary biliary cirrhosis (PBC), affecting individuals at all stages of disease. The pathogenesis of fatigue in PBC is unknown although rat models suggest a central nervous system (CNS) cause. We examined the hypothesis that a CNS abnormality related to cholestasis, rather than cirrhosis per se, underlies this symptom. PATIENTS AND METHODS: Fourteen patients with precirrhotic PBC (stage I-II disease), four patients with stage III-IV PBC, and 11 healthy women were studied using cerebral magnetisation contrast imaging and proton magnetic resonance spectroscopy (MRS). RESULTS: The globus pallidus magnetisation transfer ratio (MTR), a quantifiable tissue characteristic that may be abnormal in the presence of normal magnetic resonance imaging, was significantly reduced in precirrhotic PBC patients compared with healthy controls. These measurements correlated with blood manganese levels and were more abnormal in the more fatigued subjects. There were no differences in MRS measurements between the three study groups, suggesting that the abnormal MTR was not related to hepatic encephalopathy. CONCLUSION: This study suggests that impairments in liver function in PBC may adversely affect the brain long before the development of cirrhosis and hepatic encephalopathy, possibly as a result of altered manganese homeostasis within the CNS.

Adult↗
PubMed1988

[Evaluation of the effect of auditory fatigue on the human ear by auditory brain stem responses (ABR). I. Effect of auditory fatigue on temporary threshold shifts of ABR].

The effects of auditory fatigue on auditory brainstem responses (ABR) were investigated in 23 normal-hearing subjects. ABR was recorded before and after exposure to fatiguing noise. Behaviourally, the auditory fatigue was tested using a temporary threshold shifts (TTS) paradigm. The latency of waves I, III, V and interwave intervals I-III, III-V, I-V were analysed as functions of stimulus intensity. In post-exposure recordings a threshold elevation, significant increase of all waves latency, increase of interwave-interval III-V at 40,50,60 dB nHL and unaltered intervals I-III, I-V were observed.

Adult↗
PubMed1987

[Fatigue in women performing work with predominantly dynamic effort. II. The social working environment and the feeling of fatigue].

The relations between the sense of fatigue and evaluation of social factors demonstrated in the so called organizational climate of a workplace have been investigated. The test groups involved women performing major knitting industry jobs: knitters (94 persons) and sorters (44 persons). A multiple regression analysis demonstrated numerous relationships between the subjective symptoms of fatigue and social climate indices (10 indices have been observed). Among the social factors, especially work organization and interpersonal relationships (among workers themselves and workers in relation to their managers) may affect the magnitude of fatigue in knitting industry-employed women.

Employee Grievances↗
PubMed1997

['Abbreviated fatigue questionnaire': a practical tool in the classification of fatigue].

The 'Shortened fatigue questionnaire' (SFQ) is a short, reliable and easily used instrument to determine the intensity of the patient's bodily fatigue. It consists of four questions which the patient answers by checking an item at a 7-point scale ('I feel tired', 'I tire easily', 'I feel fit' and 'I feel physically exhausted'). The physician can then calculate a total score and compare it with the score in standard groups (standardized by load-bearing). The questionnaire can be completed simply and quickly. It constitutes a valuable addition in daily medical practice and in clinical scientific studies for the assessment of fatigue complaints.

Adult↗
PubMed1998

Effects of staphylococcus toxoid vaccine on pain and fatigue in patients with fibromyalgia/chronic fatigue syndrome.

Positive results of pilot studies of the effect of staphylococcus toxoid vaccine in patients with fibromyalgia and chronic fatigue syndrome were the incitement to the present, placebo-controlled study. It included 28 patients who fulfilled the criteria for both fibromyalgia and chronic fatigue syndrome. The effect of vaccination with a staphylococcus toxoid was compared with the effect of injections of sterile water. Psychometric assessment was made using 15 items from the comprehensive psychopathological rating scale (CPRS), Zung's self-rating depression scale and clinical global impressions (CGI). The visual analogue scale (VAS) was used to measure pain levels, and a hand-held electronic pressure algometer was used to measure pressure pain thresholds. Significant improvement was seen in seven of the 15 CPRS items in the vaccine group when pretreatment values were compared to post-treatment values. In CPRS < >, there were significant intergroup differences, and in CPRS < > intergroup differences bordered on significance. There was no significant improvement in CPRS items in the placebo group. Clinical global impressions showed significant improvement in the vaccine-treated group, and VAS did so in both groups. In a follow-up study of 23 patients, the vaccine treatment was continued for 2-6 years. Fifty percent were rehabilitated successfully and resumed half-time or full-time work. The results of this study support the authors>> hypothesis that treatment with staphylococcus toxoid may be a fruitful strategy in patients with fibromyalgia and chronic fatigue syndrome. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗
PubMed2005

Damage rate is a predictor of fatigue life and creep strain rate in tensile fatigue of human cortical bone samples.

We present results on the growth of damage in 29 fatigue tests of human femoral cortical bone from four individuals, aged 53-79. In these tests we examine the interdependency of stress, cycles to failure, rate of creep strain, and rate of modulus loss. The behavior of creep rates has been reported recently for the same donors as an effect of stress and cycles. In the present paper we first examine how the evolution of damage (drop in modulus per cycle) is associated with the stress level or the "normalized stress" level (stress divided by specimen modulus), and results show the rate of modulus loss fits better as a function of normalized stress. However, we find here that even better correlations can be established between either the cycles to failure or creep rates versus rates of damage than any of these three measures versus normalized stress. The data indicate that damage rates can be excellent predictors of fatigue life and creep strain rates in tensile fatigue of human cortical bone for use in practical problems and computer simulations.

Aged↗
PubMed1999

Examination of Cloninger's basic dimensions of personality in fatiguing illness: chronic fatigue syndrome and multiple sclerosis.

Relatively few studies have examined the personality characteristics of patients with chronic fatigue syndrome (CFS). The personality profiles of 38 CFS subjects were compared with 40 healthy controls and 40 subjects with multiple sclerosis (MS), a chronic illness that shares many symptoms with CFS (e.g., fatigue), but has a known neurological substrate. Subjects were examined within Cloninger's biosocial theory of personality, which delineates basic dimensions of temperament. Both illness groups displayed similarly elevated levels of Harm Avoidance, and lower levels of Reward Dependence as compared with healthy controls. The MS group showed a lower level of Persistence than controls and CFS subjects. Implications for the relationship between chronic illness and personality are discussed.

Adult↗
PubMed2003

Perceived exertion in fatiguing illness: civilians with chronic fatigue syndrome.

PURPOSE: It has been reported that ratings of perceived exertion (RPE) are elevated in chronic fatigue syndrome (CFS). However, methodological limitations have rendered this conclusion suspect. The purpose of the present investigation was to examine RPE during exercise in civilians with CFS by comparing subjects at both absolute exercise stage and relative oxygen consumption reference criteria. METHODS: A sample of 39 civilian females (N = 19 CFS, 34 +/- 7 yr; N = 20 healthy controls, 33 +/- 7 yr) underwent a maximal exercise test on a treadmill. RPE were obtained during the last 15 s of each 3-min stage using Borg's 6-20 scale. RESULTS: There were no significant differences in peak [OV0312]O(2), RER, or RPE. However, controls exercised longer (20.0 +/- 1.1 vs 15.9 +/- 1.1 min, P = 0.01, healthy vs CFS) and had higher peak HR (183 +/- 3 vs 174 +/- 2 bpm, P = 0.03, healthy vs CFS). Civilians with CFS reported higher RPE at stages 3 through 5 compared with controls (F(3,111)= 3.6,P = 0.017). Preexercise fatigue ratings were not a significant predictor of perceived exertion during exercise. There were no group differences (F(1,37)= 1.9, P = 0.17) when RPE were expressed relative to peak [OV0312]O(2). CONCLUSIONS: Our results show that RPE are greater in civilians with CFS when the data are expressed in terms of absolute exercise intensity. However, by examining RPE relative to a common maximum (i.e., peak [OV0312]O(2)) no differences were observed. The findings of the present investigation challenge the notion that RPE are dysregulated in CFS.

Adult↗
PubMed1999

Idiopathic chronic fatigue and chronic fatigue syndrome: a comparison of two case-definitions.

The aim of the study was to compare the signs and symptoms of individuals meeting two different definitions of chronic fatigue syndrome (CFS). Ninety-four patients fitting the eligibility criteria for idiopathic fatigue were enrolled into the study. Of the 94 patients, 48 met the 1988 definition of CFS, 20 the 1994 (but not the 1988) definition of CFS, and 26 met neither definition. The 1994 defined cases were more likely than 1988 defined cases, and non-syndromal individuals to be male, married, and high school educated. The 1994 cases were less likely than 1988 cases to present acute onset, self reported sore throat, mild fever lymphadenopathy, pharyngitis. In conclusion, the 1994 criteria increased the number of patients classified as CFS; however, those who fit only the 1994 criteria were less likely to have an acute symptomatic onset and signs and symptoms suggestive of an infectious process.

Adolescent↗
PubMed1995

Outcome and prognosis of patients with chronic fatigue vs chronic fatigue syndrome.

BACKGROUND: There are few data on the natural history and prognosis of persons with chronic fatigue (CF) or CF syndrome (CFS). Therefore, we compared functional outcomes in patients with each condition and tested the validity of various prognostic indicators. METHODS: Four hundred forty-five (89%) of 498 consecutive referral patients were surveyed an average of 1.5 years after an initial evaluation. Data from the initial evaluation were used to predict outcomes. RESULTS: Sixty-four percent of all patients reported improvement, but only 2% reported complete resolution of symptoms. Patients initially diagnosed as having CFS reported greater symptom severity and lower level of functioning at follow-up than did patients with CF. Major depression predicted unemployment in the CF group. Older age, longer duration of illness, and a lifetime history of dysthymia predicted less improvement in the CF group. Current dysthymia predicted less improvement for the CFS group. CONCLUSIONS: The case definition of CFS according to the Centers for Disease Control and Prevention identifies chronically fatigued patients with poorer prognosis. In a tertiary care setting, recovery from CF or CFS is rare, but improvement is common. Prognostic indicators vary for the two groups, but the coexistence of dysthymia suggests poorer outcomes generally.

Adult↗
PubMed2005

Anorectal manometry: are fatigue rate and fatigue rate index of any clinical importance?

BACKGROUND: Loss of voluntary contraction of the external anal sphincter is thought to be a factor in fecal incontinence. During anal manometry, computerized systems produce several parameters including fatigue rate (FR), which is the basis for calculating the fatigue rate index (FRI). Our aim was to evaluate FR and FRI and their clinical importance in patients suffering from fecal incontinence or severe constipation. MATERIALS AND METHODS: All patients scheduled for an anal physiology work-up were included in the study. FR was determined by a computer program and FRI was calculated manually with the following equation: FRI (minutes) = [squeeze pressure (mm Hg) - resting pressure (mmHg)] / - FR (mmHg/min). FR and FRI were compared in patients suffering from fecal incontinence (group I) and severe constipation (group II). Furthermore, subgroups (<50 and > or = 50 years of age) were compared. Lastly, a possible relation between length of the high-pressure zone (HPZ) and FR and FRI was assessed. RESULTS: Between January 2000 and December 2004, 131 patients (96 with fecal incontinence, 35 with constipation) were studied. Both FR and FRI were similar between groups I and II; no significant differences were found when younger and older patients were compared within the same group. We also did not find any relation between HPZ length and either FR or FRI. CONCLUSIONS: FR and FRI do not seem to be helpful in routine colorectal practice for evaluating the strength of the external anal sphincter.

Adult↗
PubMed1996

Depression in fatiguing illness: comparing patients with chronic fatigue syndrome, multiple sclerosis and depression.

Because depression is commonly observed in the chronic fatigue syndrome (CFS), the present study sought to determine whether the symptom pattern is similar to that seen in clinically depressed subjects (DEP). Individuals with multiple sclerosis (MS) were chosen as an additional comparison group because MS is a fatiguing illness of known organic etiology. The Beck Depression Inventory (BDI) was used to compare categories of depressive symptomatology. Absolute scores on the BDI were higher for the depressed group on mood and self-reproach symptoms, but were not higher than the CFS group on somatic and vegetative items. Analysis of symptoms as a percentage of total BDI score revealed no significant differences in mood or vegetative items among the three groups. The CFS and MS groups exhibited a significantly lower percentage of self-reproach symptoms than DEP, whereas the DEP group showed a lower percentage of somatic symptoms than the CFS and MS groups.

Adult↗
PubMed2005

Urinary electrophoretic profiles from chronic fatigue syndrome and chronic fatigue syndrome/fibromyalgia patients: a pilot study for achieving their normalization.

Aim of our study was to determine if there were distinct, disease-related patterns of urinary analytes in chronic fatigue syndrome (CFS) and chronic fatigue syndrome/fibromyalgia (CFS/FM) compared to normal controls (NC). Urine was collected from these subjects for two consecutive 24 h periods and aliquots were submitted to micellar electrokinetic chromatography (MEKC). To compensate for the differences in peak migration times, these were normalized from the 35 min duration of run to a 100-point scale, and each peak was assigned its normalized time measure. Peak heights were also normalized by dividing the mAU by that of the internal standard (creatinine) and multiplying by 100. MEKC with normalization for peak height and migration time generated comparable results within each of the patient groups. CFS/FM and CFS had significant differences in peaks compared to NC that may be of significance as biomarkers of illnesses.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2003

Chronic fatigue syndrome: new evidence for a central fatigue disorder.

Considerable evidence points towards a prominent role for central nervous system (CNS) mechanisms in the pathogenesis of chronic fatigue syndrome (CFS), a disorder characterized chiefly by persistent, often debilitating, fatigue. We wished to characterize circulating profiles of putative amino acid modulators of CNS 5-hydroxytryptamine (5-HT; serotoninergic) and dopaminergic function in CFS patients at rest, as well as during symptom-limited exercise and subsequent recovery. Groups of 12 CFS patients and 11 age- and sex-matched sedentary controls, with similar physical activity histories, underwent ramp-incremental exercise to the limit of tolerance. Plasma amino acid concentrations, oxygen uptake and ratings of perceived exertion were measured at rest, and during exercise and recovery. Peak oxygen uptake was significantly lower in the CFS patients compared with controls. Rating of perceived exertion in the patients was higher at all time points measured, including at rest, relative to controls. Levels of free tryptophan (free Trp), the rate-limiting 5-HT precursor, were significantly higher in CFS patients at exhaustion and during recovery, whereas concentrations of branched-chain amino acids (BCAA) and large neutral amino acids (LNAA) were lower in CFS patients at exhaustion, and for LNAA also during recovery. Consequently, the [free Trp]/[BCAA] and [free Trp]/[LNAA] ratios were significantly higher in CFS patients, except at rest. On the other hand, levels of tyrosine, the rate-limiting dopaminergic precursor, were significantly lower at all time points in the CFS patients. The significant differences observed in a number of key putative CNS 5-HT and dopaminergic modulators, coupled with the exacerbated perception of effort, provide further evidence for a potentially significant role for CNS mechanisms in the pathogenesis of CFS.

Adult↗
PubMed1999

Demonstration of delayed recovery from fatiguing exercise in chronic fatigue syndrome.

Patients with the chronic fatigue syndrome (CFS) complain consistently of delay in recovery of peripheral muscle function after exercise. The purpose of this study was to try to confirm this observation. A fatiguing exercise test was carried out on the quadriceps muscle group of ten patients and ten control subjects. The test consisted of 18 maximum voluntary contractions (MVCs) with a 50% duty cycle (10 s contraction, 10 s rest), and the force generated by each contraction was recorded using a KinCom dynamometer. This was followed by a recovery phase lasting 200 min in which quadriceps strength was evaluated at increasing intervals, and a follow-up session at 24 h post-exercise involving three 10 s MVCs. Throughout the exercise period, the MVCs obtained from the control group were significantly higher than those of the patient group (P = 0.006), but both groups showed a parallel decline in force over the 18 contractions, in keeping with a similar endurance capacity. Recovery was prolonged in the patient group, however, with a significant difference compared to initial MVCs being evident during the recovery phase after exercise (P = 0.001) and also at 24 h (P < 0.001). In contrast, the control group achieved MVCs which were not significantly different from initial values during the recovery phase, and maintained these at 24 h. These findings support the clinical complaint of delayed recovery after exercise in patients with CFS.

Adult↗
PubMed1995

Mental effects of caffeine in fatigued and non-fatigued female and male subjects.

In experiment 1 eight male and eight female subjects were randomly assigned to either a caffeine or a placebo condition. Caffeine (150 mg) was given at midnight and at 4 a.m. Oral temperature, subjective ratings of fatigue and mood, and performance in two cognitive tasks (an auditive attention task and a visual coding task) were assessed. Subjective 'drowsiness' and 'tiredness' increased significantly more in subjects given placebo than in subjects given caffeine treatment. The effects of drug treatment in performance and temperature were non-significant. However, the temperature of female subjects increased between midnight and 4 a.m. and the temperature of male subjects decreased during the same period of time. On the other hand, at 5 a.m. female subjects rated themselves as more sleepy, tired and 'disorganized' than the male subjects. In experiment 2 nine female and nine male subjects were assigned randomly to either placebo or caffeine treatment. Caffeine (200 mg) was given at 5 a.m. Oral temperature, subjective ratings of fatigue and mood, and level of performance in three cognitive tasks (the same as above plus Raven's progressive matrices) were assessed. Moreover, the subjects rated the effort of performing each task. The effects of drug treatment in level of performance were non-significant. However, the subjective effort of performing the auditive attention task increased significantly in subjects given placebo treatment, suggesting a compensatory arousal mechanism (Broadbent 1971). The effect of gender on temperature was non-significant. There was a significant interaction between gender and treatment in respect of subjective effort of performing the matrices task. In men caffeine decreased subjective effort and in women subjective effort was increased by caffeine. Experiment 3 was set up to investigate the hypothesis that negative effects of caffeine in women, observed in experiment 2, were due to over-optimal ('vigilance-related') arousal for the visual coding and matrices tasks. Ten female and eight male non-sleep deprived subjects were given 200 mg caffeine or placebos at 3 p.m. and tested at 4 p.m. Experiment 3 was not found to support the over-optimal 'vigilance-related-arousal' hypothesis. Effects of caffeine in performance and effort were non-significant in experiment 3. Combining data from experiments 2 and 3 gave a significant three-way interaction between caffeine, time for experiment and rule complexity in the visual coding task. When there was a complex rule, caffeine was found to have a positive effect in experiment 3 and a negative effect in experiment 2.

Adult↗
PubMed2001

A community-based study of seasonal variation in the onset of chronic fatigue syndrome and idiopathic chronic fatigue.

One proposed hypothesis regarding the etiology of chronic fatigue syndrome (CFS) is that there is a subgroup of patients in which symptom onset is precipitated by a viral infection. If this is indeed true, then one would anticipate a greater incidence of the emergence of CFS symptoms during months when viral infections occur with the greatest frequency. The current community-based epidemiology study examined the month of symptom onset for 31 patients with CFS and 44 others with idiopathic chronic fatigue (ICF). It was determined that the distribution of the month of illness onset for the CFS and ICF groups was nonrandom, with greater numbers of participants than expected reporting an onset of CFS and ICF during January.

Adult↗
PubMed2006

Sleep characteristics of persons with chronic fatigue syndrome and non-fatigued controls: results from a population-based study.

BACKGROUND: The etiology and pathophysiology of chronic fatigue syndrome (CFS) remain inchoate. Attempts to elucidate the pathophysiology must consider sleep physiology, as unrefreshing sleep is the most commonly reported of the 8 case-defining symptoms of CFS. Although published studies have consistently reported inefficient sleep and documented a variable occurrence of previously undiagnosed primary sleep disorders, they have not identified characteristic disturbances in sleep architecture or a distinctive pattern of polysomnographic abnormalities associated with CFS. METHODS: This study recruited CFS cases and non-fatigued controls from a population based study of CFS in Wichita, Kansas. Participants spent two nights in the research unit of a local hospital and underwent overnight polysomnographic and daytime multiple sleep latency testing in order to characterize sleep architecture. RESULTS: Approximately 18% of persons with CFS and 7% of asymptomatic controls were diagnosed with severe primary sleep disorders and were excluded from further analysis. These rates were not significantly different. Persons with CFS had a significantly higher mean frequency of obstructive apnea per hour (p = .003); however, the difference was not clinically meaningful. Other characteristics of sleep architecture did not differ between persons with CFS and controls. CONCLUSION: Although disordered breathing during sleep may be associated with CFS, this study generally did not provide evidence that altered sleep architecture is a critical factor in CFS. Future studies should further scrutinize the relationship between subjective sleep quality relative to objective polysomnographic measures.

Case-Control Studies↗