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Fatigue is a serious issue for the rail industry, increasing inefficiency and accident risk. The performance of 20 train drivers in a rail simulator was investigated at low, moderate and high fatigue levels. Psychomotor vigilance (PVT), self-rated performance and subjective alertness were also assessed. Alertness, PVT reaction times, extreme speed violations (>25% above the limit) and penalty brake applications increased with increasing fatigue level. In contrast, fuel use, draft (stretch) forces and braking errors were highest at moderate fatigue levels. Thus, at high fatigue levels, errors involving a failure to act (errors of omission) increased, whereas incorrect responses (errors of commission) decreased. The differential effect of fatigue on error types can be explained through a cognitive disengagement with the virtual train at high fatigue levels. Interaction with the train reduced dramatically, and accident risk increased. Awareness of fatigue-related performance changes was moderate at best. These findings are of operational concern. Keywords: Performance; Fatigue; Self-awareness

The present study aimed to investigate how induced lingual fatigue affected lingual strength, articulatory kinematics, and perceptual speech features in CS, a 51-year-old female with active myasthenia gravis (MG), and [...]

Beta blockers do not increase the risk of depression, fatigue, or sexual problems, according to researchers who analyzed 15 studies involving more than 35,000 patients who took beta blockers to treat heart attack, heart failure, or hypertension. This is important because beta blockers can benefit many patients, but many doctors do not prescribe them., Context: [beta]-Blocker therapy remains substantially underused in cardiac patients despite its proven mortality benefits. Reluctance to prescribe these agents may derive from concerns about their association with symptoms of depression, fatigue, and sexual dysfunction. Objective: To determine the association of [beta]-blockers with depressive symptoms, fatigue, and sexual dysfunction by performing a quantitative review of randomized trials that tested [beta]-blockers in myocardial infarction, heart failure, and hypertension. Data Sources: Randomized trials of [beta]-blockers used in the treatment of myocardial infarction, heart failure, or hypertension were identified by searching the MEDLINE database for English-language articles (1966-2001). In addition, we searched the reference lists of previously published trials and reviews of [beta]-blockers for additional studies. Study Selection: Criteria for inclusion of trials in the review were: random allocation of study treatments, placebo control, noncrossover design, enrollment of at least 100 patients, and a minimum of 6 months of follow-up. The initial search produced 475 articles, 42 of which met these criteria. Fifteen of these trials reported on depressive symptoms, fatigue, or sexual dysfunction and were selected for inclusion. Data Extraction: For each trial, 1 author abstracted the frequency of adverse events in the [beta]-blocker and placebo groups and the numbers of patients randomized to the treatment groups. Two other authors verified the counts of events, and all authors adjudicated any discrepancies. Two different types of information on adverse events were abstracted: patient-reported symptoms and withdrawal of therapy due to a specified symptom. We categorized the tested [beta]-blockers by generation (early vs late) and lipid solubility (high vs low to moderate). Data Synthesis: The 15 trials involved more than 35000 subjects. [beta]-Blocker therapy was not associated with a significant absolute annual increase in risk of reported depressive symptoms (6 per 1000 patients; 95% confidence interval [CI], -7 to 19). [beta]-Blockers were associated with a small significant annual increase in risk of reported fatigue (18 per 1000 patients; 95% CI, 5-30), equivalent to 1 additional report of fatigue for every 57 patients treated per year with [beta]-blockers. [beta]-Blockers were also associated with a small, significant annual increase in risk of reported sexual dysfunction (5 per 1000 patients; 95% CI, 2-8), equivalent to one additional report for every 199 patients treated per year. None of the risks of adverse effects differed significantly by degree of [beta]-blocker lipid solubility. The risk associated with reported fatigue was significantly higher for early-generation than for late-generation [beta]-blockers (P=.04). Conclusion: The conventional wisdom that [beta]-blocker therapy is associated with substantial risks of depressive symptoms, fatigue, and sexual dysfunction is not supported by data from clinical trials. There is no significant increased risk of depressive symptoms and only small increased risks of fatigue and sexual dysfunction. The risks of these adverse effects should be put in the context of the documented benefits of these medications.

Byline: E. G. Antonen (1), A. Yu. Meigal (1), L. I. Gerasimova (1), Yu. V. Lupandin (1) Abstract: The process of muscular fatigue was studied in ten patients (at the age of 59--65 years) with the rigid akinetic form of Parkinson's disease under cooling (+10degC, 60 min), during therapy (Nakom or Cyclodol), as compared to neutral thermal conditions (+22degC), using surface electromyography (EMG) and turn-amplitude analysis. Clear stages were found in the pattern of change of the turn-amplitude analysis, both in neutral thermal conditions and under cooling. A thermoregulatory component of the muscular activity was found after cooling and fatigue at small static loads. In addition, cooling and fatigue brought about an alleviation of the hidden tremor component of the EMG in patients with Parkinson's disease (in 30% of cases) and therefore can serve as a functional test. Cooling and dynamic loads reduce muscular power and decrease oligobradykinesia. Author Affiliation: (1) Petrozavodsk State University, Petrozavodsk, Russia Article History: Registration Date: 16/10/2004

NOS is a key enzyme in the production of NO, a molecule that directly regulates vasorelaxation and blood supply. Diverse forms of muscle disease have been clinically associated with unusual fatigue after exercise. The localization of neuronal NOS (nNOS) at the plasma membrane of muscle has recently been shown to prevent muscle fatigue after exercise. In this issue of the JCI, Lai et al. show that dystrophin--the structural protein missing in individuals with Duchenne muscular dystrophy--anchors nNOS to the sarcolemma through a direct interaction with dystrophin spectrin-like repeats 16 and 17 (see the related article beginning on page 624). Furthermore, in another recently reported study of mouse models of muscular dystrophy, phosphodiesterase 5A inhibitors were used to treat the downstream ischemia that is associated with nNOS mislocalization. Collectively, these findings significantly advance our understanding of exercise-induced muscle fatigue and its role in muscle disease., Dystrophin localizes neuronal NOS to the plasma membrane of muscle The dystrophin-associated protein complex (Figure 1) is found at the plasma membrane of skeletal muscle, where it provides stability to [...]

Byline: Guru. Karthikeyan, Divita. Jumnani, Rama. Prabhu, Udaya. Manoor, Sanjay. Supe Background: Fatigue is disabling and continuous phenomenon in cancer patients during and after various anticancer treatments which can continue [...]