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Mental Performance (mental + performance)
Selected AbstractsRhythms of Mental PerformanceMIND, BRAIN, AND EDUCATION, Issue 1 2008Pablo Valdez ABSTRACT, Cognitive performance is affected by an individual's characteristics and the environment, as well as by the nature of the task and the amount of practice at it. Mental performance tests range in complexity and include subjective estimates of mood, simple objective tests (reaction time), and measures of complex performance that require decisions to be made and priorities set. Mental performance tasks show 2 components, a circadian rhythm and the effects of time awake. The circadian rhythm is in phase with the rhythm of core temperature and there is evidence for a causal link. Increasing time awake results in performance deterioration and is attributed to fatigue. The relative contribution of these 2 components depends upon the task under consideration; simple tasks generally show smaller effects due to increasing time awake. These contributions have been assessed by constant routines and forced desynchronization protocols and have formed the basis of several mathematical models that attempt to predict performance in a variety of field conditions. Mental performance is negatively affected by sleep loss; although short naps are beneficial, sleep inertia limits their value immediately after waking. The processes involved in cognition include attention (tonic and phasic alertness, and selective and sustained attention), working memory (phonological, used for speech, reading, and writing; and visuospatial, used for spatial processing, drawing, and mathematics), and executive function (initiative, decision making, and problem solving). These processes are illuminated by analysis of the regions of the brain involved, the presence of circadian rhythmicity, and the effects of sleep loss. The results from such laboratory- and field-based observations are relevant to the issue of learning in schoolchildren and lead to suggestions for improving their performance. [source] Hydration and health: a reviewNUTRITION BULLETIN, Issue 1 2010B. Benelam Summary Water is essential for life and maintaining optimal levels of hydration is important for humans to function well. Water makes up a large proportion of our body weight (60% on average), distributed between the intracellular (inside cells) and extracellular (water in the blood and in between cells) compartments. Water is the major component of body fluids, such as blood, synovial fluid (fluid in the joints), saliva and urine, which perform vital functions in the body. The concentration of solutes (osmolality) in body fluids is closely controlled, and even very small changes in osmolality trigger a physiological response; either to increase body water by reducing urinary output and stimulating thirst; or to excrete excess water as urine. Generally, body water is maintained within narrow limits. However, if water losses are not sufficiently replaced, dehydration occurs. Extreme dehydration is very serious and can be fatal. More mild dehydration (about 2% loss of body weight) can result in headaches, fatigue and reduced physical and mental performance. It is also possible to consume too much water and in rare cases this can result in hyponatraemia (low levels of sodium in the blood). We can get water from almost all drinks and from some foods in the diet. Food provides about 20% on average and this could vary widely depending on the types of food chosen. We also get water from all the drinks we consume, with the exception of stronger alcoholic drinks like wines and spirits. All these can contribute to dietary water, but also have other effects on health both positive and negative. The major concerns with regards to beverages are their energy content and their effect on dental health. With obesity levels continuing to increase it is important for many in the population to control their energy intake, and drinks as well as foods must be considered for their energy content. With regards to dental health, there are two concerns; dental caries and dental erosion. Dental caries are caused by a reduction in pH due to bacterial fermentation of carbohydrates, and so the frequency of consumption of drinks containing sugars is a concern for risk of caries. Dental erosion occurs at a lower pH and is caused by the consumption of acidic foods and drinks, in particular, citrus juices and soft drinks containing acids. Individual water needs vary widely depending on many factors including body size and composition, the environment and levels of physical activity. Thus it is very difficult to make generic recommendations about the amount of water to consume. The FSA currently recommends drinking about 1.2 litres per day (about 6,8 glasses). [source] The Effects of Ginseng, Ephedrine, and Caffeine on Cognitive Performance, Mood and EnergyNUTRITION REVIEWS, Issue 4 2001Harris R. Lieberman Ph.D. A variety of claims regarding the purported energy-enhancing properties of nutritional supplements and food constituents have recently been made. It appears that the supplements most frequently associated with such assertions are ginseng, ephedrine, and caffeine. Claims of increased energy are difficult to evaluate objectively because their meaning is not usually defined or specified. Often it is not clear whether the claims refer to physical or mental energy or both. Furthermore, an agreed upon scientific definition of either physical or mental energy enhancement does not exist. In spite of obvious differences in what the term physical energy, as opposed to mental energy implies, there is no clear scientific consensus on whether there is a difference between the two types of energy. Because the substances in question have been anecdotally associated with improvements in both physical and mental performance, their effects on both functions will be discussed, but with an emphasis placed on cognitive function and mood. Of the three substances discussed, caffeine's effects on cognitive and physical function, mood, and energy are best understood. It is clear that this food/drug enhances these functions when administered in moderate doses. Ephedrine may also enhance certain physical and mental functions related to "energy," but the evidence that ginseng has such properties is exceedingly weak. [source] A pharmacogenomic approach to Alzheimer's diseaseACTA NEUROLOGICA SCANDINAVICA, Issue 2000R. Cacabelos Single nucleotide polymorphisms (susceptibility genetics) and genomic point mutations (mendelian genetics) can be used in Alzheimer's disease (AD) for diagnostic, predictive and therapeutic purposes. Using a matrix genetic model, including APOE, PS1 and PS2 allelic variants, we have studied the distribution of 36 different genotypes in the AD population (N=479) and the genotype-related cognitive response to a multifactorial therapy in AD patients with mild-to-moderate dementia. The 10 most frequent AD genotypes are the following: 1) E33P112P2+ (17.75%), 2) E33P112P2, (15.55%), 3) E33P111P2+ (10.85%), 4) E34P112P2+ (9.60%), 5) E34P112P2, (7.56%), 6) E33P111P2, (7.10%), 7) E34P111P2+ (4.80%), 8) E33P122P2+ (4.38%), 9) E34P111P2, (4.18%), and 10) E34P122P2+ (3.55%). APOE-4/4-related genotypes represent less than 3% in the following order: E44P112P2+> E44P111P2+=E44P111P2,>E44P112P2+>E44P122P2+= E44P122P2,. Multifactorial therapy with CDP-choline (1000 mg/day)+piracetam (2400 mg/day)+anapsos (360 mg/day) did improve mental performance during the first 6,15 months in a genotype-specific fashion. The best responders in the APOE series were patients with APOE-3/4 genotype (r=+0.013), while the worst responders were APOE-4/4 patients (r=,0.93). PS1-related genotypes responded in a similar manner; and patients with a defective PS2 gene exon 5 (PS2+) always showed a poorer therapeutic response than PS2, patients. All these data suggest that the therapeutic outcome in AD exhibits a genotype-specific pattern, and that a pharmacogenomic approach to AD might be a valuable strategy for drug development and monitoring. [source] | ||||||||||