Factors Impairing Human Performance

Research and anecdotal evidence indicate that a number of factors can impair human performance. While working in complex surroundings, humans can easily experience a limited short-term memory. Running late or being in a hurry can impact task performance. Some individuals find it very difficult to multitask. 

Others lose their concentration due to job or task interruption. Healthcare workers and professionals should deal with stress, lack of sleep, and fatigue on the job. Workplace environmental factors, personal or home distractions, and substance abuse can also impair performance. James Reason in his studies developed some questions to address errors committed on the job. Consider the following questions when investigating an error or other adverse event  

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List at least five factors impairing human performance. Define an industrial robot. 

Another important consideration in the selection of an impairment testing system is whether norm-based decision criteria will be used to evaluate readiness to perform an assignment and, if so, whether such norms are currently available. It is important that such norms address both decrements and improvements in performance, as improved performance may also signal the influence of a risk factor. For example, stimulant medications may have minimal effect on performance of most tasks, but under test conditions requiring sustained attention, enhanced performance may be noted.14 These same doses of stimulant medication may have important implications for more complex dimensions of human behavior,15 16 so the detection of enhanced performance may signal an increased risk for detrimental effects on other more complex behaviors that are not directly measured during testing. 

To examine the possible cause-effect relationship between human exposure to Pfiesteria-detived materials and the reported neurobehavioral impairments, a rat model was developed [89]. Using a radial-arm maze, learning and memory was examined in rats exposed to Pfiesteria extracts. Although it was proposed that individuals were affected by Pfiesteria toxin(s) most likely by breathing aerosol in the estuarine environment, possible ingesting of water, or by transdermal absorption by direct contact with contaminated water, the actual route(s) of exposure remained uncertain. Therefore, the subcutaneous injection of Pfiesteria cells or toxic bioassay aquarium water to experimental animals was chosen to ensure the delivery of a reliable toxin dose. Abnormal behaviors caused by injection of the abovementioned Pfiesteria-demed materials were reported to be relatively specific to the acquisition phase in the training procedure. When rats were pretrained, Pfiesteria treatment did not affect performance. Nevertheless, factor(s) affecting rat performance in the radial-arm maze remain unknown, because the purified Pfiesteria toxin has not been available. 

While non-human primates may be the most relevant animals, practical and economic factors have made rodents the most widely used model. The small size of the mouse can be a handicap, but there are several well-defined strains which offer a wide range of features. For example, NMRI strain-aged mice provide evidence for cognitive impairment (Morris water maze, passive avoidance). But in this model, neurochemical changes do not correlate with performance in learning and memory tasks [28]. In one specific strain, the senescence- accelerated mouse (SAM), age-related changes in learning and memory have been reported [29]. 

Multiple factors associated with copper deficiency are responsible for the increased rate of infection seen. Most copper-deficient patients are malnourished and suffer from impaired weight gain. The immune system requires copper to perform several functions. Recent research showed that interleukin 2 is reduced in copper deficiency and is probably the mechanism by which T-cell proliferation is reduced. These results were extended to show that even in marginal deficiency, when common indexes of copper are not affected by the diet, the proliferative response and interleukin concentrations are reduced. The number of neutrophils in human peripheral blood is reduced in cases of severe copper deficiency. Not only are they reduced in number, but their ability to generate superoxide anion and kill ingested microorganisms is also reduced in both overt and marginal copper deficiency. This mechanism is not yet understood. 

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