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Results for “Balance ability”

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At least 379 records · Page 21Linked to original sources

PubMed2000

Now you see it, now you don't; consent and the legal protection of autonomy.

In this paper I describe the piecemeal development of the law regarding capacity to consent to treatment. I note how the requirement has changed from Justice Cardozo's low-level requirement of a 'sound mind' to the relatively high-level Re C test. I discuss the limitations of the Re C test. Particularly, that the requirements from believing information and ability to weigh information in the balance--which should be applied to the patient's ability to decide and not the actual treatment decision--are open to subjective abuse and the risk of abductive inferences made from the patient's actual decision. I suggest that, because of a generally poor standard of reasoning ability, only a minimal level of rationality should be required. Furthermore, I demonstrate the fallacy of the judicially approved risk related standard and discuss the Catch-22 situation that arises when it is implemented.

Adult↗

PubMed2000

Balance control and posture differences in the anxious BALB/cByJ mice compared to the non anxious C57BL/6J mice.

A relation between anxiety disorders and balance control dysfunctions has been observed in many studies in humans. A mismatch in the integration of sensory inputs could trigger these disturbances. Very few experimental animal procedures have been designed to study the functional link between anxiety and balance control. A task was therefore developed, challenging the visual, vestibular and somesthesic sensory systems in mice. The test, called the 'rotating beam', gave an accurate assessment of balance control and the posture, using sensitive measures (number of falls and imbalances, position of tail and trunk). Striking differences were observed between the two inbred strains of mice known to have radically different anxiety-related behaviour. The highly anxious strain, BALB/cByJ, performed poorly compared to the non anxious strain, C57BL/6J. Balance control and postural abilities of anxious mice were improved by acute anxiolytic diazepam treatment. Lower behavioural performance level was registered in non anxious mice given anxiogenic beta-CCM treatment. The findings account for a strong relationship between anxiety and balance control in mice. Finally, the highly sensitive procedure proved to be well suited to the study of functional links between anxiety and sensorimotor processes.

Animals↗

PubMed1994

A prospective study of postural balance and risk of falling in an ambulatory and independent elderly population.

BACKGROUND: An ability to predict risk of future falling is needed in order to target high-risk individuals for preventive intervention. The purpose of this study was to compare the ability of different measures of postural balance to predict risk of falling prospectively in an ambulatory and independent elderly population. METHODS: Balance tests were performed on 100 volunteers (aged 62-96), and falling was then monitored prospectively over a one-year period. The balance testing comprised measurements of: (a) spontaneous postural sway, (b) induced anterior-posterior sway, (c) induced medial-lateral sway, (d) anticipatory adjustments preceding volitional arm movements, (e) timed one-leg stance, and (f) performance on a clinical balance assessment scale. Small pseudorandom platform motions were used to perturb balance in the induced-sway tests. Using force plates, the spontaneous- and induced-sway responses were quantified in terms of the amplitude, speed, and mean frequency of the center-of-pressure displacement; input-output models were also used to parameterize the induced-sway performance. RESULTS: Although a number of measures showed evidence of significant differences between fallers and nonfallers, the differences were most pronounced for measures related to the control of lateral stability. Lateral spontaneous-sway amplitude (blindfolded conditions) was found to be the single best predictor of future falling risk, particularly for the large group of falls that were precipitated by a biomechanical perturbation. This measure was able to predict future falling risk with moderate accuracy, even in those individuals with no recent history of falling. CONCLUSIONS: The results suggest that control of lateral stability may be an important area for fall-preventative intervention. The ability of a simple and safe force-plate measure of spontaneous postural sway to predict future falling risk suggests a possible clinical application as a preliminary screening tool for risk of falling.

Accidental Falls↗

PubMed2005

"Starve a fever and feed a cold": feeding and anorexia may be adaptive behavioral modulators of autonomic and T helper balance.

Anorexia is a common symptom accompanying infections, but the teleology of the phenomenon remains unexplained. We hypothesize that anorexia may represent a prehistoric behavioral adaptation to fight infection by maintaining T helper (Th)2 bias, which is particularly vital in fighting bacterial pathogens. Specifically, we propose that anorexia may avert the reduction of Th2/Th1 ratio by preventing feeding-induced neurohormonal and vagal output from the gut. Emerging evidence suggests that the vagal and neurohormonal output of the gut during feeding promotes Th1 function, which is desirable in fighting viral infections. Since fever may be an adaptation to fight bacteria and "colds" are generally viral in origin, the adage "starve a fever and feed a cold" may reflect a sensible behavioral strategy to tilt autonomic and Th balance in directions that are optimal for fighting the particular type of infection. The ability to modulate T helper balance through the neurohormonal and autonomic axis by adjusting food intake may be the mechanism behind other unexplained clinical observations such as the improved outcomes of ICU patients after enteric versus parenteric feedings. Compared to the prehistoric period when bacterial infection was commonplace, the anorexic response may be less adaptive today when viruses and cancers have become common triggers of anorexia. By promoting host anorexia, cachexia, and insomnia, cancers and viruses can deter behaviors such as digestion and sleep that would raise vagal and Th1 activity against tumors and viruses. Hydration and sleep, unexplained but widely accepted recommendations for flu patients, may also work by promoting vagal and Th1 functions. Modulating feeding, hydration, and sleep may prove beneficial in treating other conditions associated with abnormal autonomic and Th balance.

Adaptation, Physiological↗

PubMed1994

Multisensory training of standing balance in older adults: I. Postural stability and one-leg stance balance.

BACKGROUND: The effects of standing balance training on the ability to maintain stability in both static two-leg and one-leg stance were tested in healthy older adults. METHODS: Subjects (age range 65-90 years) were randomly assigned to a training (n = 12) or control group (n = 12). Training subjects received a 10-hour balance training program which selectively manipulated sensory inputs from the visual, vestibular, and somatosensory systems. RESULTS: Training subjects showed significantly improved stability (root-mean-square values of anteroposterior platform torque) after training in five of the eight training conditions (when somatosensory inputs were changed or when two or more sensory systems were simultaneously manipulated) (p < .006). When tested 4 weeks after completion of training, subjects (a) fell less frequently when the ankle/foot somatosensory inputs were minimized and (b) stood longer on one leg than the control group (p < .001). CONCLUSIONS: Balance training designed to improve intersensory interaction could effectively improve balance performance in healthy older adults.

Accidental Falls↗

PubMed1977

A new device for the rapid measurement of impaired motor function in mice.

Measurement of the ability of mice to balance on a rotating rod or cone is often used as a measure of impaired motor function. In most of these procedures the mice must be trained prior to the test. In the new screen test described in this paper, untrained mice are used in a 60 sec test which measures the ability of mice to either climb to the top of or cling to the bottom of a horizontal screen. The ED50 values obtained for failure to reach the top of the horizontal screen are similar to those obtained with the rotarod; the values for falling from the screen are somewhat higher. With both of the horizontal screen measures there were fewer control failures than in the rotarod procedure.

Animals↗

PubMed1999

Preliminary investigation of the lateral postural stability of spinal cord-injured individuals subjected to dynamic perturbations.

STUDY DESIGN: A study of the impact of spinal cord injury (SCI) on seated balance was conducted by comparing the results obtained from experiments with able-bodied and SCI subjects. OBJECTIVES: The purpose of this preliminary study was to examine the lateral postural stability of seated individuals with SCI in a dynamic environment. SETTING: Experiments were conducted at the Cleveland Clinic Foundation in Cleveland, Ohio. METHODS: Controlled perturbations were applied to each subject, seated in a wheelchair, through the use of a servo-controlled tilt platform. The platform was rotated so as to create disturbances similar in nature to those experienced in the frontal plane during left turns in a vehicle. Four quadriplegic, four paraplegic, and five able-bodied subjects participated in this study. Kinematic information and center of pressure (COP) movement were recorded. RESULTS: None of the spinal cord-injured subjects was able to maintain his stability when exposed to the stronger perturbations, while all of the able-bodied subjects stayed upright for all of the trials. On an individual basis, injury level was not always indicative of balance. However, regression results suggest a correlation between ability to perform static leaning and dynamic balance (P<0.001). CONCLUSIONS: SCI subjects lost stability under dynamic conditions even though they were stable in the static situation. Initial results also raise some questions about where and when external support may be needed. Information of this nature could help to guide the design of new lateral supports with improved client acceptance.

Adult↗

PubMed2003

A clinical model for the assessment of posture and balance in people with stroke.

PURPOSE: The lack of models to define and describe rehabilitation processes have often been identified as limiting research and the development of clinical practice. This study describes the development of a clinical model to address a key aspect of stroke physiotherapy--the assessment of posture and balance. METHOD: Twenty seven experienced neurological physiotherapists (PT) in six focus groups were used. Participants were shown photographs of a typical stroke patient in sitting and standing positions and were asked 'What would you note if you were assessing the posture and balance of this patient?' Answers were displayed on flip charts to allow immediate feedback about the accuracy and completeness of data. Thematic content analysis was then used. RESULTS: A complex reasoning process emerged to answer three main questions: What can the patient do? How does s/he do it? Why does s/he do it that way? To answer these questions physiotherapists established balance disability (by observing the patient's ability to perform a series of increasingly demanding balance tasks), identified postural and movement impairments (by observing alignment and movement of body segments relative to each other and to the expected norm for that patient) and assessed muscle activity (by observation and palpation). CONCLUSIONS: Focus groups have been used to elicit a clinical model for the assessment of posture and balance, the content of which will be used to inform a new outcome measure.

Evaluation Studies as Topic↗

PubMed1993

Physiological aspects and injury in elite Alpine skiers.

Alpine skiing requires aerobic and anaerobic power, muscular strength, and a variety of complex motor abilities including quickness, agility, balance and coordination. There is evidence of variability in physical characteristics between skiers of different events. Generally, successful alpine competitors are taller and heavier than in the past. Greater size, specifically lean mass, may be related to technique changes because of the advent of breakaway poles. Aerobic power, although important, does not discriminate competitors of varying ability categories. Aerobic power is more likely to be a result of conditioning for alpine skiing rather than a profound requirement of the sport. Anaerobic power is important for skiing and both laboratory and field power tests correlate well with performance. Tests that measure explosive and sustained anaerobic power such as the Wingate, vertical jump, 60-second repeated jump, and Margaria-Kalamen stair run are valuable in assessing skiers. On-snow lactate and oxygen consumption measurements further substantiate the need for high anaerobic power. Alpine skiers have very high leg strength compared with other athletes. Isokinetic testing has been used to evaluate dynamic leg strength in skiers, but little is known about high speed dynamic or eccentric strength capabilities. A new mechanism of knee injury that is associated with tibial acceleration has been identified in competitive alpine skiers. A release binding that is sensitive to physiological factors in addition to release forces should be developed. Strength profiling of skiers may also be valuable in evaluating injury risk.

Anaerobic Threshold↗

PubMed1993

The effect of a 12-week dynamic resistance strength training program on gait velocity and balance of older adults.

This study tested whether a 12-week dynamic resistance strength training program can change gait velocity and improve measures of balance among adults age 65 and older. Fifty-five community-dwelling adults (mean age = 71.1) were randomized into an exercise (n = 25) or control (n = 30) group. The exercisers were requested to complete three bouts of strength training per week for 12 weeks using elastic tubing. At posttest the exercisers demonstrated slower gait velocity, enhanced balance, and an improved ability to walk backward, although none of these posttest measures was significantly different from the control group.

Age Factors↗

PubMed1998

Glucocorticoid-induced type 1/type 2 cytokine alterations in humans: a model for stress-related immune dysfunction.

Increased psychologic and physiologic stressors can have profound effects on the immune system. Previously believed to be immunosuppressive, there is mounting evidence that stress may actually induce a shift in the type 1/type 2 cytokine balance toward a type 2 cytokine response. Cortisol is elevated in response to stress and has been reported to alter cytokine production in murine and human peripheral blood mononuclear cells (PBMC). The current investigation examined the effects of dexamethasone (DEX) mimicking basal, stress, and supraphysiologic levels of cortisol on production of interferon-gamma (IFN-gamma) (type-1), interleukin (IL)-12p40 (type 1), IL-10 (type 2), and IL-4 (type 2) by human PBMC. Both supraphysiologic and stress levels of DEX decreased production of type 1 cytokines and either increased or maintained production of type 2 cytokines PBMC stimulated with phytohemagglutinin (PHA), immobilized anti-CD3, lipopolysaccharide (LPS) or tetanus. Although preincubation with DEX was sufficient to induce a type 2 switch in short-term mitogen cultures, PBMC cultures for extended periods of time required DEX at the initiation and throughout the duration of culture. Mifepristone, a glucocorticoid receptor antagonist, blocked the DEX-induced shift in the type 1/type 2 cytokine balance. These data demonstrated the ability of the glucocorticoid dexamethasone, to induce a shift in the type 1/type 2 cytokine balance toward a type 2 cytokine response and simulate the type 1/type 2 cytokine alterations observed in in vivo stress models. This model will allow detailed investigation of the cellular and molecular mechanisms of stress-induced immune alterations in humans.

Adult↗

PubMedDate not supplied

Mental abilities of workers exposed to aluminium.

The authors tested the psychic abilities of workers occupationally exposed for several years to high environmental aluminium concentrations with psychomotor ability tests, Wechsler's test of intelligence and Bender's test for estimation of cerebral damage. Slower psychomotor reaction and dissociation of oculomotor coordination were found in the exposed workers. Also, exposed workers had reduced memory ability and their mental and emotional balance was disturbed. The observed changes in psychomotor and intellectual abilities could be a consequence of the long-lasting toxic effects of aluminium.

Adult↗

PubMed2003

Separation of fine particulate matter emitted from gasoline and diesel vehicles using chemical mass balancing techniques.

Samples of fine particulate matter were collected in a roadway tunnel near Houston, TX over a period of 4 days during two separate sampling periods: one sampling period from 1200 to 1400 local time and another sampling period from 1600 to 1800 local time. During the two sampling periods, the tunnel traffic contained roughly equivalent numbers of heavy-duty diesel trucks. However, during the late afternoon sampling period, the tunnel contained twice as many light-duty gasoline-powered vehicles. The effect of this shift in the vehicle fleet affects the overall emission index (grams pollutant emitted per kilogram carbon in fuel) for fine particles and fine particulate elemental carbon. Additionally, this shift in the fraction of diesel vehicles in the tunnel is used to determine if the chemical mass balancing techniques used to track emissions from gasoline-powered and diesel-powered emissions accurately separates these two emission categories. The results show that the chemical mass balancing calculations apportion roughly equal amounts of the particulate matter measured to diesel vehicles between the two periods and attribute almost twice as much particulate matter in the late afternoon sampling period to gasoline vehicles. Both of these results are consistent with the traffic volume of gasoline and diesel vehicles in the tunnel in the two separate periods and validate the ability for chemical mass balancing techniques to separate these two primary sources of fine particles.

Air Pollutants↗

PubMed2003

Adaptation of the nematode Caenorhabditis elegans to extreme osmotic stress.

The ability to control osmotic balance is essential for cellular life. Cellular osmotic homeostasis is maintained by accumulation and loss of inorganic ions and organic osmolytes. Although osmoregulation has been studied extensively in many cell types, major gaps exist in our molecular understanding of this essential process. Because of its numerous experimental advantages, the nematode Caenorhabditis elegans provides a powerful model system to characterize the genetic basis of animal cell osmoregulation. We therefore characterized the ability of worms to adapt to extreme osmotic stress. Exposure of worms to high-salt growth agar causes rapid shrinkage. Survival is normal on agar containing up to 200 mM NaCl. When grown on 200 mM NaCl for 2 wk, worms are able to survive well on agar containing up to 500 mM NaCl. HPLC analysis demonstrated that levels of the organic osmolyte glycerol increase 15- to 20-fold in nematodes grown on 200 mM NaCl agar. Accumulation of glycerol begins 3 h after exposure to hypertonic stress and peaks by 24 h. Glycerol accumulation is mediated primarily by synthesis from metabolic precursors. Consistent with this finding, hypertonicity increases transcriptional expression of glycerol 3-phosphate dehydrogenase, an enzyme that is rate limiting for hypertonicity-induced glycerol synthesis in yeast. Worms adapted to high salt swell and then return to their initial body volume when exposed to low-salt agar. During recovery from hypertonic stress, glycerol levels fall rapidly and glycerol excretion increases approximately fivefold. Our studies provide the first description of osmotic adaptation in C. elegans and provide the foundation for genetic and functional genomic analysis of animal cell osmoregulation.

Adaptation, Physiological↗

PubMed1998

Energy balance in muscle activity: simulations of ATPase coupled to oxidative phosphorylation and to creatine kinase.

Energy balance refers to the dynamic homeostasis of ATP and related forms of chemical potential within cells. This regulation is accomplished mainly by oxidative metabolism in most mammals. This homeostasis matches dynamically the energy demands of cellular ATPases (net decrease in chemical potential energy) with the energy supply by mitochondrial oxidative phosphorylation (net increase in chemical potential energy). Muscle cells are distinguished from most other cell types in their ability to attain energy balance with more than a 10-fold range of ATPase demand. Creatine kinase maintains a near to equilibrium flux: PCr + ADP<-->ATP + Cr. One important function of creatine kinase is to buffer ATP and ADP concentrations. A system of differential equations describe the coupled operation of cellular ATPase, creatine kinase and oxidative phosphorylation. These equations used experimentally measured concentrations of relevant metabolites and enzyme activities to simulate energy balance in muscle cells. The principle of energy balance is adequately illustrated by simulations with only a three component system.

Adenosine Diphosphate↗

PubMed2006

Hypoxia, drug therapy and toxicity.

Hypoxia is defined as a decrease in available oxygen reaching the tissues of the body. It is linked to the pathology of cancer, cardiovascular disease, and stroke, the leading causes of death in the United States. Cells under hypoxic stress either induce an adaptive response that includes increasing the rates of glycolysis and angiogenesis or undergo cell death by promoting apoptosis or necrosis. The ability of cells to maintain a balance between adaptation and cell death is regulated by a family of transcription factors called the hypoxia inducible factors (HIF). HIF1, the most widely studied HIF, is essential for regulating the expression of a battery of hypoxia-responsive genes involved in the adaptive and cell death responses. The ability of HIF1 to balance these 2 responses likely lies in the regulation of HIF1alpha stability and transcriptional activity by post-translational hydroxylation and its ability to respond to other cellular factors including key metabolites and growth factors. Targeting HIF1 signaling for therapeutics, therefore, requires an understanding of how these various signals converge upon HIF1 and regulate its role in maintaining the balance between adaptation and cell death. In addition, one must understand how this balance can be perturbed during toxicant-induced tissue damage. This review will summarize our current understanding of hypoxia signaling as it applies to drug therapy and toxicity and describe how these processes can influence the HIF-mediated balance between adaptation and cell death.

Animals↗

PubMed2004

Myocyte hypertrophy and apoptosis: a balancing act.

In response to a variety of extrinsic and intrinsic stimuli that impose increased biomechanical stress the heart responds by enlarging the individual myofibers. Even though myocardial hypertrophy can normalize wall tension, it instigates an unfavorable outcome and threatens affected patients with sudden death or progression to overt heart failure, suggesting that in most instances hypertrophy is a maladaptive process. Increasing evidence suggests that several of the signaling cascades controlling myocyte growth in the adult heart also function to enhance survival of the myocyte population in response to pleiotropic death stimuli. In this review, we summarize recent insights into hypertrophic signaling pathways and their ability to control the balance between myocyte life and death. As modulation of myocardial growth by antagonizing intracellular signaling pathways is increasingly recognized as a potentially auspicious approach to prevent and treat heart failure, the design of such therapies should respect the dichotomous action of pathways that dictate a balance between myocyte hypertrophy, survival and death.

Animals↗

PubMed1981

Chelation therapy in beta-thalassemia major. III. The role of splenectomy in achieving iron balance.

Transfusion requirements for 1978 were compiled for 79 patients with thalassemia major (ages 1 to 29 years) who were maintained at hemoglobin concentrations of greater than 10 gm/dl. In 46 patients with intact spleens, the mean transfusion requirement was 258 ml/kg/year, and there was a clear increase with age. The transfusion history prior to 1978 had no influence on the increase of transfusion requirement with age. In contrast, in 33 splenectomized patients, the mean transfusion requirement was 203 ml/kg/year and it did not increase with age. Urinary iron excretion in response to deferoxamine increased with age, with no obvious difference between splenectomized and nonsplenectomized patients. The ability to achieve iron balance with a daily dose of 20 mg/kg of deferoxamine was a function of the transfusion requirement splenectomized patients with lower blood requirements generally achieved negative iron balance, whereas nonsplenectomized patients did not. We conclude that the spleen should be removed when the transfusion requirement exceeds 250 ml/kg/year, which usually occurs between 6 and 8 years of age. In young patients with intact spleens, a higher dose of deferoxamine may be use in order to prevent hemosiderosis.

Adolescent↗