Effects of dyslexia on postural control in adults.

Dyslexia has been shown to affect postural control. The aim of the present study was to investigate the difference in postural stability measured as torque variance in an adult dyslexic group (n=14, determined using the Adult Dyslexia Checklist (ADCL) and nonsense word repetition test) and an adult non-dyslexic group (n=39) on a firm surface and on a foam block and with eyes open and eyes closed. Another aim was to investigate the correlation between ADCL scores and postural stability. Findings showed that ADCL scores correlated with torque variance in the anteroposterior direction on foam with eyes closed (p=0.001) and in the lateral direction on the foam surface with eyes closed (p=0.040) and open (p=0.010). General Linear Model analysis showed that high dyslexia scores were associated with increased torque variance (p<0.001). However, we found no significant difference between dyslexics and non-dyslexics, though there were indications of larger torque variance in the dyslexics. The findings suggest that adults with high dyslexic ADCL scores may experience sub-clinical balance deficits. Hence, assessing motor ability and postural control in those with high ADCL scores is motivated.

The effect of foam surface properties on postural stability assessment while standing.

A common assessment of postural control often involves subjects standing on a compliant surface, such as a foam block, to make balance tests more challenging. However, the physical properties of the foam block used by different researchers can vary considerably. The objective of this study was to provide an initial approach for investigating whether two of the foam properties, i.e. density and elastic modulus, influenced recorded anteroposterior and lateral torque variance with eyes open and eyes closed. Thirty healthy adults (mean age 22.5 years) were assessed with posturography using three different types of foam block placed on a force platform. These blocks were categorised: firm foam, medium foam and soft foam by their elastic modulus. To investigate the spectral characteristics of recorded body movements, variance values were calculated for total movements, movements <0.1Hz and movements >0.1Hz. Results showed that anteroposterior and lateral torque variances >0.1Hz were larger when standing on the firm foam compared with medium and soft foam and in turn were larger on the medium foam compared with the soft foam with eyes closed. Moreover, GLM and correlation analysis demonstrated that the properties of the foam blocks affected anteroposterior torque variance >0.1Hz and lateral torque variance in all frequency ranges. In addition, the stabilising effect of vision in the anteroposterior direction had a greater influence when the subjects' stability was increasingly challenged by the support surface, as illustrated by the higher torque variance values. In conclusion, caution should be taken when analysing balance deficits with foam test setups, because the foam properties may influence the recorded body movements.

The effects of foam surface properties on standing body movement.

CONCLUSION: The properties of a foam surface significantly affect body movement variance. Therefore, studies where different kinds of foam have been used may not provide congruent results. OBJECTIVES: To investigate whether different properties of foam affect body movement variance (32 subjects, mean age 22.5 years) in terms of linear head, shoulder, hip and knee movements. Subjects repeated tests with eyes open and closed, to also determine the effect of vision on the different surfaces. SUBJECTS AND METHODS: Body movement was captured on three different foam surfaces and on a control solid surface over 2 min using a Zebris ultrasound measuring system. The foam surfaces were categorized by their firmness as firm foam, medium foam and soft foam. RESULTS: Body movement variance increased significantly when standing on all foam surfaces compared with the solid surface. However, movement variance was larger when standing on the firm foam compared with the softer foams, except in the anteroposterior total and low frequency ranges. We also found that the body movement pattern differed when standing on foam and firm surfaces, with greater reliance on movements at the knee to give postural stability on foam than on the solid surface. Vision clearly reduced all body movement variances, but particularly within the high frequency range.

Screening for depression in medical patients. Is the focus too narrow?

There is growing consensus that depression is a major public health problem causing significant psychosocial morbidity and mortality which should be addressed by case-finding effects in primary care settings. A large amount of literature has examined the ability of self-report questionnaires to detect depression in medical patients and the results have been encouraging. However, studies of general population and psychiatric patient samples indicate that depression is frequently comorbid with other psychiatric disorders, and that psychiatric disorders other than depression are also associated with significant morbidity and mortality. Consequently, we believe that psychiatric screening in primary care should be broad based. We administered a newly developed, multidimensional questionnaire (the SCREENER), that simultaneously screens for a range of DSM-III-R psychiatric disorders, to 508 medical outpatients attending a VA general medical clinic. Compared with nondepressed cases, the depressed patients significantly more often reported all of the nondepressive symptoms. Nine of the ten nondepressive disorders screened for by the SCREENER were significantly more frequent in the depressed group. Most patients who screened positive for depression also screened positive for at least one nondepressive disorder. Compared with patients who only screened positive for depression, those who screened positive for both depression and a nondepressive disorder rated their physical and emotional health more poorly and made more visits to the doctor. Compared with patients who did not screen positive for any disorder, those who only screened positive for a nondepressive disorder rated their physical and emotional health more poorly, and more frequently had a history of mental health treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Psychiatric screening in geriatric primary care: should it be for depression alone?

Depression in the elderly is highly prevalent, associated with functional disability and increased medical costs, and treatable; however, it is infrequently recognized and treated. The Agency for Health Care Policy and Research has advocated, therefore, increased case-finding efforts for depression in primary geriatric care. Anxiety, substance, and somatoform disorders in the elderly are similarly prevalent, associated with disability and cost, treatable, and also infrequently detected and treated. We believe that psychiatric case-finding in geriatric primary care should attend to these disorders, therefore, as well as to depression. In the present study, we examined whether the association between depressive and nondepressive forms of psychopathology was similar in geriatric and nongeriatric medical patients. We also examined the relationship between each type of pathology and health care utilization and global ratings of physical and mental health. In a VA hospital general medical outpatient clinic, 508 patients completed the SCREENER, which is a brief self-report questionnaire that screens for a range of psychiatric disorders, along with a self-report questionnaire regarding subjective health and medical care utilization. Of these patients, 98% were male, and the median age was 63 years. Patients aged 63 and over were compared to younger patients. In both geriatric and younger adult patients, we found substantial comorbidity between depressive and nondepressive forms of pathology. Moreover, in both age groups, there were significant associations between both depressive and nondepressive symptoms and fair-to-poor self-rated physical and mental health and increased medical care utilization. Approximately half of the cases of nondepressive disorders in the elderly were not comorbid with depression, and thus would not have been detected by screening for depression alone. Therefore, psychiatric case finding in primary care of geriatric males should be directed at anxiety, substance, and somatoform disorders, as well as at depression, for treatment resources to be triaged to maximally decrease morbidity and cost.

Psychiatric screening in primary care: what do patients really want?

Psychiatric disorders are common in primary care, but underdiagnosed. U.S. physician reluctance to diagnose psychiatric illnesses is partly attributable to the belief that patients do not want their primary care physician to assess mental health. Six hundred one patients in a U.S. general internal medicine practice completed the SCREENER, a self-report questionnaire which screens for 15 psychiatric disorders, and another questionnaire about the SCREENER. Patients were predominantly female, unmarried, black, high school graduates. Only 3% thought that their physician should never evaluate their mental health. More than 60% desired periodic mental health screening, and one third wanted psychiatric assessment only when a problem was suspected. Attitudes toward questionnaire screening were less positive than toward physician interview. Patients were more likely to want screening if they were female, unmarried, young, had a history of mental health treatment, reported psychiatric symptoms, or were in fair-poor subjective physical or mental health.

Screening programs in the population at large and in high-risk groups.

Existing guidelines for colorectal cancer screening in standard risk patients are reviewed, as well as the data on which they are based. A family history of colorectal cancer or significant adenoma increases the risk above that of standard risk individuals. Risk assessment and surveillance in higher risk individuals are discussed.

Measles vaccine effectiveness in central Australian aboriginal children vaccinated at or after eight months of age.

An outbreak of measles in central Australia in 1994 provided the first opportunity to evaluate the effectiveness of the measles vaccine given to Aboriginal children at nine months of age since 1984. Children eligible for the study that was conducted in one community in the region were aged between nine months and 10 years. Eight of the 109 eligible children developed measles. The only unvaccinated child also developed measles. Vaccination failures occurred in 7.8% (6/77) of children vaccinated between eight and 11 months of age and in 3.2% (1/31) vaccinated after 11 months of age. Overall vaccine effectiveness was 93.5%. The level of vaccine uptake in central Australia is high and the last region-wide outbreak before 1994 occurred in 1981-82. If the age of vaccination against measles is to be determined by the average age of infection; the age of vaccination should now be raised to 12 months of age; this is the age at which Aboriginal children in all other states and all children in Australia are vaccinated.

Leprosy control in the Northern Territory.

An epidemic of leprosy occurred among Aboriginal people of the Top End of the Northern Territory following its introduction towards the end of the 19th Century. The extent of this outbreak became apparent through community surveys conducted in the 1950s which revealed that one in 10 Aboriginal people in some areas were affected by leprosy. Initial control activities were outbreak-focused, directed at case finding and management. Case finding was by systematic community survey. Case management included appropriate rehabilitation and reconstructive surgery. Regular review of treated patients ensured early detection of relapse and detection and treatment of sequelae. Education and full participation of Aboriginal health workers in the diagnosis and management of cases provided local expertise at the hospital and community level. The case detection rate fell from 270 per 100,000 in the Aboriginal population in 1951 to four per 100,000 in 1997. Elimination of transmission is now the objective of the control program. Combining of the tuberculosis and leprosy control activities of the Territory Health Service in 1996 resulted in increased efficiency of the mycobacterial services.

Investigation of notifications of hepatitis C in 1994: the experience of three health departments.

Laboratories must notify health departments of cases of hepatitis C in Queensland, the Northern Territory (NT) and the Australian Capital Territory (ACT). Our objectives were to estimate the minimum proportion of notified cases of hepatitis C that were recent infections and to determine the risk factors for infection of the notified cases. We conducted a retrospective investigation of all eligible notifications received at the health departments in Queensland, the Northern Territory and the Australian Capital Territory. Of the 963 notifications about which information was received, 16 per cent were repeat notifications. These were excluded from further analysis. In Queensland, 7 per cent, and in both NT and ACT, 3 per cent of the notifications were considered to be recent infections. The most common risk factor reported for both recent and all other hepatitis C cases was a history of injecting drug use, although the proportion of cases with that history was different in NT from ACT and Queensland. Cases were tested because of screening programs: for drugs and alcohol, in sexually transmitted diseases clinics and prison; and because of clinical indications such as a risk factor, symptoms, or results of liver function tests. Another common reason for testing was a request from a patient. A significant proportion of recorded notifications was repeat notifications. Most notifications were of patients who had become infected more than 12 months ago and the most common risk factor was injecting drug use. There was not a high proportion of cases with unknown risk factors.

Coronary artery disease. The latest on prevention.

Because coronary artery disease is the most common cause of death in the United States, much effort is being focused on research into prevention of this killer. Dr. Lush reviews positive and negative aspects of recent trends and summarizes the results of studies on the prophylactic potential of maintenance of normal body weight, exercise, aspirin, fish oils, estrogens, and antioxidants.

Screening for colorectal cancer. Use of a new protocol may reduce death rates.

The goal of screening for colorectal cancer is to find early, asymptomatic cancers and adenomatous polyps that are 1 cm or more in diameter or that are villous or tubulovillous histologically. A study using fecal occult blood testing with rehydration and no sigmoidoscopy found that deaths from colorectal cancer can be reduced by screening. Although this protocol is effective in screening, whether it is the optimal approach remains to be determined. Flexible sigmoidoscopy as a screening method has not been studied, except in nonrandomized tests. However, since endoscopic diagnosis and treatment is ultimately the means by which benefits from fecal occult blood testing are realized and since flexible sigmoidoscopy visualizes more than half of colon cancers and colon polyps, it seems logical that this method would be an effective screening test. Whether doing both rehydrated fecal occult blood testing and flexible sigmoidoscopy enhances results is unknown. It seems appropriate to use the rehydration method when fecal occult blood testing is done and flexible sigmoidoscopy when endoscopy is done. Fecal occult blood testing should precede sigmoidoscopy so that patients with a positive result can go directly to colonoscopy and avoid two procedures.

Preventing heart disease and cancer. What randomized, primary-prevention studies show.

Several chemical agents appear to be useful in primary prevention of CAD and cancer. Randomized trials have found that in specific patient subgroups, tamoxifen and raloxifene decreased the occurrence of breast cancer, and lovastatin and aspirin decreased the frequency of CAD events. Secondary analysis of randomized primary-prevention studies has supported the use of vitamin E and selenium in cancer prevention.

Adaptation and vision change the relationship between muscle activity of the lower limbs and body movement during human balance perturbations.

OBJECTIVE: Investigate the relationship between changes in lower limb EMG root mean square (RMS) activity and changes in body movement during perturbed standing. Specifically, linear movement variance, torque variance and body posture were correlated against tibialis anterior and gastrocnemius RMS EMG activity during perturbed standing by vibration of the calf muscles. METHODS: Eighteen healthy participants (mean age 29.1 years) stood quietly for 30s before vibration pulses were randomly applied to the calf muscles over a period of 200 s with eyes open or closed. Movement variance, torque variance and RMS EMG activity were separated into five periods, thereby allowing us to explore any time-varying changes of the relationships. RESULTS: Changes of tibialis anterior muscles EMG activity were positively correlated with changes in linear movement variance and torque variance throughout most of the trials, and negatively correlated with some mean angular position changes during the last 2 min of the trials. Moreover, the initial changes in Gastrocnemius EMG activity were associated with initial changes of mean angular position. Additionally, both tibialis anterior and gastrocnemius muscle activities were more involved in the initial control of stability with eyes closed than with eyes open. CONCLUSIONS: Visual information and adaptation change the association between muscle activity and movement when standing is perturbed by calf muscle vibration. SIGNIFICANCE: Access to visual information changes the standing strategy to calf muscle vibrations. Training evoking adaptation could benefit those susceptible to falls by optimising the association between muscle activities and stabilising body movement.

Advance directives and living wills.

Advance directives are documents which enable people to decide what will happen to them, or who will make decisions on their behalf, if a time comes when they are no longer able to participate in discussions or decisions about their own health care. This paper briefly examines the underlying philosophy of advance directives, and the manner in which they have evolved in the United States. It concludes by considering their legal status in the United Kingdom which, until recently, was not entirely clear.

Steady-state autoregulation of renal blood flow: a myogenic model.

This paper presents a model of myogenic control of renal blood flow based on the proposition that steady-state flow occurs when the distending and constricting forces acting on the afferent arteriole are equal. The distending force is represented by the Laplace relationship. The opposing force is governed by the properties of the arterioles and has two components--a purely passive component and an "active" component resulting from vascular smooth muscle contraction. Within the myogenic model, vascular smooth muscle contraction is initiated by "stretch"-induced changes in calcium permeability. Terms are developed describing the effect of stretch on calcium permeability, intracellular calcium, and contractile activity. The model is adapted to describe the myogenic control of blood flow in the dog kidney. Sigmoidal relationships between stretch and calcium permeability and between intracellular calcium and muscle tension seem to account for the shape of the autoregulatory curve. The model predicts a shifting of the autoregulatory pressure-flow curve upward and to the right in response to increased tissue hydrostatic pressure. The model is also exquisitely sensitive to changes in the parameters governing intracellular calcium. These predictions agree well with experimental observations.

Regulation of renin processing and secretion: chemiosmotic control and novel secretory pathway.

The renin-angiotensin-aldosterone system (RAAS) plays an important role in cardiovascular and electrolyte regulation in health and disease. Juxtaglomerular cells in the kidney regulate endocrine RAAS by physiologically controlling conversion of prorenin and secretion of renin. The classical baroceptor, neurogenic, and macula densa mechanisms regulate renin expression at the cellular level by Ca2+, adenosine 3',5'-cyclic monophosphate (cAMP), and chemiosmotic forces (K+, Cl-, and water flux coupled to H+ movement). The baroceptor mechanism (through Ca2+) activates K+ and Cl- channels in the surface membrane and deactivates a KCl-H+ exchange chemiosmotic transporter in the secretory granular membrane. The neurogenic mechanism (through cAMP) promotes prorenin processing to renin. The macula densa mechanism (through K+ and Cl-) involves the processing of prorenin to renin. Ca2+, by inhibiting the KCl-H+ exchange transporter, prevents secretory granules from engaging in chemiosmotically mediated exocytosis. cAMP, on the other hand, by stimulating H+ influx, provides the acidic granular environment for prorenin processing to renin. It is concluded that, in the presence of a favorable chemiosmotic environment, prorenin is processed to renin, which may then be secreted by regulative degranulation or divergence translocation, a novel secretory pathway used by several secretory proteins, including renin.

Interrelationship of blood flow, juxtaglomerular cells, and hypertension: role of physical equilibrium and Ca.

Recent experimental evidence has provided important clues as to the role of electrolytes, particularly Ca, in the regulation of blood flow, renin secretion, and blood pressure. The smooth muscle cells of arterioles in general and the juxtaglomerular cells in the renal afferent arterioles have been shown to have Ca channels sensitive to voltage, hormones, and stretch. This paper reviews a model that utilizes these features along with a fundamental law of physics to point to some plausible explanations for some interesting experimental observations on renal blood flow, renin secretion, and hypertension. The chief features of the model are that in the steady state the arteriole must achieve a stable physical equilibrium in which the forces tending to distend the vessel (transmural pressure) counterbalance the forces tending to prevent distension (wall tension); the wall tension consists of a passive and an active component, the latter of which is sensitive to stretch of the vessel; and stretch activates the opening of stretch-sensitive Ca permeability channels that promote the influx of Ca to trigger active tension development. Thus Ca is the signal that couples stretch to contraction. This latter feature is the so-called myogenic response. Altered equilibrium may be initiated either by a rise in perfusion or tissue pressure to alter the distending force or by a rise in cytosolic Ca to increase active tension development and the constricting force. Several factors may initiate disequilibrium, some of which are discussed. Equilibrium is soon reestablished, however, at a new steady state. The model predicts curves for renal blood flow autoregulation and renin secretion in response to changes in renal perfusion pressure, tissue pressure, extracellular Ca, and blockers and promoters of Ca influx and Ca efflux. These predictions agree well with existing experimental evidence and suggest new experiments. The model provides a theoretical basis for explaining the steady-state blood pressure profile observed in renovascular hypertension and perhaps in other forms of hypertension as well. The model also provides a theoretical basis for understanding the volume-vasoconstriction approach used by some workers and the autoregulation approach used by others in explaining the mechanisms of hypertension.(ABSTRACT TRUNCATED AT 400 WORDS)

Furosemide fails to alter plasma active or inactive renin in conscious sheep but does so in anaesthetized animals.

Regulation of plasma levels of active and inactive renin was investigated using sheep with indwelling artery, vein and bladder catheters. Control and experimental studies were carried out in the same animals on different days. Volume depletion during any single experiment was limited to a maximum of 50 ml. Despite large changes in sodium and water excretion, the diuretic furosemide at two dose levels, 1 and 10 mg/kg, failed to alter plasma levels of either active or inactive renin in conscious sheep. Induction of pentobarbitone anaesthesia in the sheep did not, per se, alter either plasma active or inactive renin. Furosemide (10 mg/kg) in anaesthetized animals produced a similar diuresis and natriuresis response to conscious sheep, but plasma active renin increased by 270% and inactive renin decreased to zero. In conscious sheep given an infusion of papaverine, furosemide also produced an increase in plasma active renin and a concurrent decrease in the inactive form. In both anaesthetized animals and in conscious sheep infused with papaverine, furosemide-induced intrarenal vasodilation, as evidenced by changes in clearance of p-aminohippuric acid, was much reduced in comparison to the conscious animals. This may be significant in relation to the control of renin secretion. It appears that the macula densa sodium receptor, which is considered to regulate renin release, will only function after it has been primed by other intra- or extrarenal factors. This is discussed, particularly in relation to the possible role played by the prostaglandin system.