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At least 73 records · Page 4Linked to original sources
PubMed2004

Anatomic evaluation of postural bronchial drainage of the lung with special reference to patients with tracheal intubation: which combination of postures provides the best simplification?

BACKGROUND: Although several sequences of specific postures, each corresponding to a particular lung segment, have been recommended for therapeutic bronchial drainage, these are based on little or no anatomic evidence. Moreover, because these sequences are too complex, especially for intubated patients, they require simplification. MATERIALS AND METHODS: The courses of the segmental bronchi B(1), B(2), B(1 + 2), B(3), and B(6) and their subsegmental bronchi are extremely variable. This can result in a small branching angle at the subsegmental bronchial origin. Using 106 lungs, we measured the branching angles of the subsegmental bronchi and examined their running directions in each posture of the sequences recommended for bronchial drainage. RESULTS: A small branching angle (< 120 degrees ) at the subsegmental bronchial origin was sometimes evident, and this made postural drainage difficult. Drainage of B(3) and B(6) was often difficult because they formed angles of < 45 degrees from the horizontal in certain postures (supine for B(3) and prone for B(6)). Further, we found a 45 degrees rotative prone position effective for draining B(1)a and B(6). CONCLUSION: Our anatomic findings predicted increased effectiveness in a sequence of postures: supine, 45 degrees rotative prone with left side up, 45 degrees rotative prone with right side up, and return to supine for simple, safe, and effective bronchial drainage, especially for patients with tracheal intubation. The 10 degrees right-side-up supine and 45 degrees rotative prone with head raised 45 degrees positions seemed helpful if added to the basic sequence.

Bronchi↗
PubMed2004

Contrasting effects of carbohydrate and water on blood pressure responses to postural maneuvers in patients with posturally related (vasovagal) syncope.

Crouching then standing induces large changes in arterial blood pressure. Ingestion of carbohydrate and water are known to have contrasting effects on cardiovascular control in patients with various forms of autonomic dysfunction. We tested the hypothesis that, in patients with attacks of posturally related (neurogenic or vasovagal) syncope, postural maneuvers would cause greater changes in blood pressure than in normal controls and that they would be affected differently by carbohydrate and water. We studied 7 patients with histories indicating posturally related syncope and who we had shown to have abnormal responses to an orthostatic stress test, and 7 healthy volunteers with normal orthostatic responses. Responses of blood pressure (Portapres finger photoplethysmography) were determined to crouching and subsequent standing, before and after ingestion of a high carbohydrate "meal" (2.5MJ) and (on a different day) water (500 ml). Before the "meal" or water there were no differences between groups in baseline blood pressures or in the responses to crouching and standing. In controls, neither carbohydrate nor water had any significant effect on baseline blood pressure or on the responses to the maneuvers. In the patients, the standing pressures were also unaffected by carbohydrate but they did increase after water. In the patients the increases in pressure during the crouch were larger after carbohydrate, but smaller after water. These results show that, in patients with posturally related syncope, unlike in control subjects, carbohydrate ingestion and water result in opposite effects on blood pressure during postural maneuvers. These results raise the possibility that these patients might have a mild form of autonomic dysfunction.

Adolescent↗
PubMed2006

Effects of preparatory period on anticipatory postural control and contingent negative variation associated with rapid arm movement in standing posture.

We investigated CNS motor preparation state and anticipatory postural muscle activation while subjects performed bilateral rapid arm movement at various intervals between warning and response stimulus (preparatory period) during standing. Motor preparation state was evaluated by integrated values of the late components of the contingent negative variation (late CNV), obtained by averaging electroencephalograms during the last 100ms of the preparatory period. For quantifying anticipatory postural muscle activation, we measured the onset of burst activity in postural muscles (lumbar paraspinal, biceps femoris, and gastrocnemius) with respect to anterior deltoid activity and integrated values of preceding activation. Subjects performed the arm movement with minimal delay in the warning stimulus-response stimulus-motor response paradigm under preparatory periods of 2.0, 3.0 and 3.5s. Late CNV did not differ between the 2.0-s and 3.0-s period, but was significantly smaller in the 3.5-s period than in the 2.0-s period, suggesting difficulty in predicting response timing in the 3.5-s period. No change was found on integrated values of preceding activations of postural muscles. Burst onset of all postural muscles significantly preceded anterior deltoid activation in all periods. Burst activity for gastrocnemius only occurred earlier in the 3.5-s period than in the 2.0-s and 3.0-s periods. Weak correlations were observed between late CNV and onset time of gastrocnemius activity. It is suggested that earlier activation of gastrocnemius is a strategy adopted when response stimulus timing is relatively difficult to predict.

Adult↗
PubMed1993

The effects of neutral posture deviations on perceived joint discomfort ratings in sitting and standing postures.

There is a pressing need to rank body deviations from neutral postures which occur due to variety of body movements around different joints. Such knowledge is needed to better understand potentially adverse effects of poor working postures on the industrial population. The main objective of this study was to examine the effects of postural deviations on perceived joint discomfort ratings assessed under similar working conditions. Twelve males and seven females participated in the laboratory study. The results revealed several distinct classes of joint deviations from neutral postures, which need to be assigned different weights of postural stress. A preliminary ranking system for assessment of stressfulness of human body deviations about different joints was proposed.

Adult↗
PubMed2004

A test of the ability to identify emotion in human standing and sitting postures: the diagnostic analysis of nonverbal accuracy-2 posture test (DANVA2-POS).

The purpose of the present study was to introduce the Diagnostic Analysis of Nonverbal Accuracy for Postures (DANVA2-POS), a test that measures an individual's ability to identify emotion in human standing and sitting postures. The authors describe the construction and selection of the test items. Types of standing and sitting postures were generated from a set of dimensions gleaned from a review of relevant theoretical and empirical literature. Two men and 2 women portraying standing and sitting postures were photographed. An empirical norming procedure was used to select 32 high- and low-intensity standing and sitting postures representing happiness, sadness, anger, and fear. Three hypotheses guided the collection of construct validity evidence. Consistent with the hypotheses, data from 243 participants showed that DANVA2-POS scores increased in accuracy with age, were internally consistent and reliable over time, and were related to self-reported loneliness, fear of negative evaluation, and locus of control. The authors report construct validity evidence from 6 additional studies. Future applications of the DANVA2-POS test are described.

Adult↗
PubMed1997

Spinal shrinkage during work in a sitting posture compared to work in a standing posture.

OBJECTIVE: The objective was to measure the possible differences in shrinkage of the thoracolumbar spine in subjects working in a sitting and a standing posture for 6.5 h at work, in a realistic work environment. The isolated shrinkage of the thoracic and the lumbar spine was also examined. STUDY DESIGN: This study presents a new protocol to measure shrinkage of the thoracic and lumbar spine separately. BACKGROUND: Controversies still exist with regard to the load on the spine in a sitting compared to a standing position. Some report that shrinkage is greatest in the sitting position while others report the reverse. However, nothing is known about the height reduction of the thoracic and the lumbar spine during loading for 6.5 h in a real work environment. Therefore, the behaviour of the thoracic and the lumbar spine under practical condition has to be investigated. METHOD: A stadiometer with a measurement error of 0.51 mm was used to measure changes in spinal height during work. To exclude first-time behaviour of the spine, a pre-test lasting 50 min was undertaken. The mean of the last three measurements was used as the reference height. During work, height measurements of the spine were performed every 20 min. To separate the behaviour of the thoracic and the lumbar spine, two benchmarks were placed at the vertebrae prominens and at the thoracic-lumbar junction. Shrinkage of the spine was investigated within three different cohorts: (I) work in a sitting posture for 6.5 h; (II) relaxed sitting for 2 h vs work for 2 h in a sitting position and (III) work in a standing position for 6.5 h. RESULTS: Relaxed sitting leads to a gain in stature compared to work in a sitting position for 2 h. The major gain in stature occurred in the lumbar spine. Comparison of cohort (III) working in a standing position with cohort (I) working in a sitting position shows that the shrinkage of the spine is greatest when work is performed in a standing posture. The major differences were found in the shrinkage of the lumbar spine, e.g. shrinkage of the lumbar spine in the standing cohort (III) was 4.16 mm compared to 1.73 mm in the sitting cohort (I). CONCLUSIONS: There is a gain in stature during relaxed sitting compared to work in a sitting posture. The load on the spine is greatest when work in a standing position is performed. The greater shrinkage of the lumbar spine during work in a standing position compared to a sitting posture is probably due to: (i) differences in lumbar lordosis and (ii) the effect of bending and torsion while handling the work materials.

Journal Article↗
PubMed2001

Age-related differences in postural control in humans in response to a sudden deceleration generated by postural disturbance.

Age-related differences in postural control in response to a relatively large deceleration resulting from postural disturbance were investigated in eight normal elderly men (age range 67-72 years) and eight young men as controls (age range 19-22 years) using a moving platform. Data were obtained for the hip, knee and ankle angles, position of the centre of foot pressure (CFP), head acceleration, and muscle activity of the leg muscles. The elderly subjects had slower and larger ankle and hip joint movements, and CFP displacement in response to the disturbance compared to the young controls. The elderly subjects also had a delayed occurrence, and greater magnitude of peak acceleration of head rotation than did the young subjects. For the elderly subjects, the CFP was closely related to angular changes in the hip joint movement, but not to those of the ankle and knee joint movements. For the young subjects, on the other hand, the CFP was significantly correlated with angular change in the ankle joint. Cocontraction of the tibialis anterior and gastrocnemius muscles was observed in the elderly subjects. The results indicated that a movement pattern for postural correction in the elderly adults was different from that of the young adults. The elderly relied more on hip movements while the young controls relied on ankle movements to control postural stability.

Adult↗
PubMed2006

The effect of asymmetry of posture on anticipatory postural adjustments.

The study investigates the effect of body asymmetry on anticipatory postural adjustments (APAs). Subjects performed a task involving a standard load release induced by a shoulder abduction movement while standing symmetrically or in an asymmetrical stance with either their right or left leg in 45 degrees of external rotation. EMG activities of trunk and leg muscles were recorded during the postural perturbation and were quantified within the time intervals typical of APAs. Anticipatory postural adjustments were observed in all experimental conditions. It was found that asymmetrical body positioning was associated with significant asymmetrical patterns of APAs seen in the right and left distal muscles. These APA asymmetries were dependant upon the side in which the body asymmetry was induced: reduced APAs were observed in the leg muscles on the side of leg rotation, while increased APAs were seen in the muscles on the contralateral side. These findings stress the important role that body asymmetries play in the control of upright posture.

Adaptation, Physiological↗
PubMed1995

Preparatory postural adjustments in parkinsonian patients with postural instability.

BACKGROUND: Postural instability is a common problem in patients with Parkinson's disease. This paper reports results of a study undertaken to investigate some of the possible mechanisms responsible for this instability. METHODS: Preparatory postural adjustments associated with a lateral leg raising task were studied in five parkinsonian patients and four age-matched controls. Recordings included ground reaction forces, kinematics, and surface EMG activity from multiple leg muscles. RESULTS: In normal subjects there was a well-defined sequence of events preceding the onset of leg elevation, beginning with a transfer of centre of foot pressure (CP), initially toward the moving leg and then back to the support side, followed by displacement of the trunk toward the support side. In the more severely affected parkinsonian patients, the amplitude of the initial displacement of CP was markedly reduced. The interval between the earliest force changes and the onset of leg elevation was prolonged and the relative timing of the kenematic adjustments during this interval was disrupted. In addition the alternating burst and periods of inhibition observed in the EMG recordings from the normal subjects were replaced by continuous tonic EMG activity. CONCLUSIONS: These observations suggest that abnormalities in programming preparatory postural adjustments may contribute to postural instability in some patients with advanced Parkinson's disease.

Aged↗
PubMed2002

Reducing the risk of falls through proprioceptive dynamic posture training in osteoporotic women with kyphotic posturing: a randomized pilot study.

OBJECTIVE: To assess the effect of a proprioceptive dynamic posture training program on balance in osteoporotic women with kyphotic posture. DESIGN: Subjects were randomly assigned to either a proprioceptive dynamic posture training program or exercise only group. Anthropometric measurements, muscle strength, level of physical activity, computerized dynamic posturography, and spine radiography were performed at baseline and 1 mo. RESULTS: At the 1-mo follow-up, three groups were formed on the basis of the baseline computerized dynamic posturography results. In general, groups 1 and 2 had no significant change at 1 mo, whereas group 3 improved balance significantly at 1 mo. CONCLUSION: The subjects who had abnormal balance and used the proprioceptive dynamic posture training program had the most significant improvement in balance. Improved balance could reduce the risk of falls.

Accidental Falls↗
PubMed1999

Aging and postural control: postural perturbations caused by changing the visual anchor.

OBJECTIVE: To determine the effect of modifying the stable visual anchor on the postural stability of older individuals. The visual anchor was changed by opening doors similar to those found in an elevator cage. Lighting intensities inside and outside the cage were varied to create increasing or decreasing luminosity conditions. The effect of adding a cognitive load (counting backwards) was also tested. DESIGN: A controlled laboratory study. SETTING: Tests performed in a balance laboratory. MEASUREMENTS: Sensory and clinical measurements to insure the integrity of the central and peripheral nervous system. Measures of balance were derived from the recordings of the center of foot pressure. These measures included range and speed of the center of foot pressure. PARTICIPANTS: Eight older, community-dwelling subjects and nine young subjects participated. A sensorimotor evaluation was used to insure that all older individuals were free from any pathologies affecting postural stability. All participants had a low score (indicating high balance confidence) on the Falls Efficacy Scale and no history of falls. RESULTS: Older individuals were affected by modification of the stable visual anchor induced by the opening of doors similar to that of an elevator cage. They showed greater ranges of the center of foot pressure (COP) and speed of the COP after than before the opening of the doors. Furthermore, the increased ranges and speed were two to three times greater than that observed for the young subjects. A lighting intensity considered as comfortable for reading inside the elevator affected the overall postural stability of the older participants negatively. Counting backwards also decreased their overall stability. CONCLUSION: Changing the stable visual anchor, as when exiting an elevator cage, could be a significant risk factor for older persons. Moreover, when combined with a cognitive load or lower lighting intensity inside the elevator cage, the negative effects on the postural stability of older persons are exacerbated.

Accidental Falls↗
PubMed1997

Anatomy and histochemistry of spread-wing posture in birds. 2. Gliding flight in the California gull, Larus californicus: a paradox of fast fibers and posture.

Gliding flight is a postural activity which requires the wings to be held in a horizontal position to support the weight of the body. Postural behaviors typically utilize isometric contractions in which no change in length takes place. Due to longer actin-myosin interactions, slow contracting muscle fibers represent an economical means for this type of contraction. In specialized soaring birds, such as vultures and pelicans, a deep layer of the pectoralis muscle, composed entirely of slow fibers, is believed to perform this function. Muscles involved in gliding posture were examined in California gulls (Larus californicus) and tested for the presence of slow fibers using myosin ATPase histochemistry and antibodies. Surprisingly small numbers of slow fibers were found in the M. extensor metacarpi radialis, M. coracobrachialis cranialis, and M. coracobrachialis caudalis, which function in wrist extension, wing protraction, and body support, respectively. The low number of slow fibers in these muscles and the absence of slow fibers in muscles associated with wing extension and primary body support suggest that gulls do not require slow fibers for their postural behaviors. Gulls also lack the deep belly to the pectoralis found in other gliding birds. Since bird muscle is highly oxidative, we hypothesize that fast muscle fibers may function to maintain wing position during gliding flight in California gulls.

Animals↗
PubMed2005

MRI study of cerebral blood flow and CSF flow dynamics in an upright posture: the effect of posture on the intracranial compliance and pressure.

Postural related changes in cerebral hemodynamics and hydrodynamics were studied using Magnetic Resonance Imaging (MRI) measurements of cerebral blood flow and cerebrospinal fluid (CSF) flow dynamics. Ten healthy volunteers (mean age 29 +/- 7) were studied in supine and upright (sitting) postures. A Cine phase-contrast MRI technique was used to image the pulsatile blood flow to the brain, the venous outflow through the internal jugular, epidural, and vertebral veins, and the bi-directional CSF flow between the cranium and the spinal canal. Previously published analyses were applied to calculate and compare total cerebral blood flow (TCBF), intracranial compliance and pressure in both postures. A lower (12%) mean TCBF was measured in the upright position compared to supine position. A considerable smaller amount of CSF flow between the cranium and the spinal canal (58%), a much larger intracranial compliance (a 2.8-fold increase), and a corresponding decrease in the MRI-derived ICP were also measured in the sitting position. These changes suggest that the increased cerebrovascular and intracranial compliances in the upright posture are primarily due to reduced amounts of blood and CSF residing in their respective intracranial compartments in the upright position. This work demonstrates the ability to quantify neurophysiologic parameters associated with regulation of cerebral hemodynamics and hydrodynamics from dynamic MR imaging of blood and CSF flows.

Adaptation, Physiological↗
PubMed2006

External postural perturbations induce multiple anticipatory postural adjustments when subjects cannot pre-select their stepping foot.

Previous research on human balance recovery suggests that, prior to an externally triggered postural perturbation, healthy subjects can pre-select their postural response based on the environmental context, but it is unclear whether this pre-selection includes the selection of a stepping leg when performing compensatory steps. We sought to determine how pre-selecting a stepping limb affects the compensatory steps and stability of young, healthy subjects when responding to postural perturbations. Nine healthy subjects (24-37 years of age) stepped in response to backward translations of a platform under their feet when, prior to the perturbations, the subjects either knew whether they were to step with their left or right leg to a visual target (the Predictable condition) or did not know whether to step with their left or right leg until one of two targets appeared at perturbation onset (the Unpredictable condition). The Unpredictable condition also included randomly inserted trials of toes-up rotations and backward translations without targets (catch trials). The results showed that, in the Predictable condition, the subjects consistently exhibited one anticipatory postural adjustment (APA; a lateral weight shift toward the stance limb) before stepping accurately to the target with the correct leg. In the Unpredictable condition, the subjects either (1) exhibited multiple APAs, late step onsets, and forward center-of-mass (CoM) displacements that were farther beyond their base of support, or (2) exhibited an early step with only one APA and kept their CoM closer to the base of support, but also stepped more often with the incorrect leg. Thus, when the subjects had to select a stepping leg at perturbation onset, they either became more unstable and used multiple APAs to delay stepping in order to provide enough time to select the correct stepping leg, or they stepped earlier to remain stable but often stepped with the incorrect leg. In addition, responses to catch trials in the Unpredictable condition included distorted step placements that resembled steps to anticipated targets, despite allowing the subjects to step with a leg of their choice and to a location of their choice. Lastly, the subjects' voluntary stepping latencies to visual targets presented without perturbations were twice as long as their stepping latencies to the backward platform translations. Therefore, healthy subjects appear to pre-select their stepping limb, even when the perturbation characteristics are unpredictable, because relying on visual input provided at perturbation onset requires a delayed response that leads to greater instability.

Adaptation, Physiological↗
PubMed1985

Haemodynamic response to postural stress in the elderly with and without postural hypotension.

The haemodynamic response to postural stress (60 degrees foot-down tilt) was measured by impedance cardiography in six elderly cardiovascular-normal patients and 39 with symptomatic postural hypotension (systolic blood pressure drop greater than or equal to 20 mmHg or more). In the normal elderly the mean increase in heart rate, fall in blood pressure and cardiac output, and rise in peripheral resistance was less than that described in younger subjects. The changes were at their maximum in 1 min, and there was little further change over the next 5 min. In those with postural hypotension, orthostatic reduction (or failure to rise) of the peripheral resistance was the mechanism in 83% of cases, whatever the cause, and the time course of the haemodynamic changes was the same in the majority as in the normals. Serial tests in patients whose postural hypotension was controlled (by cessation of causal drugs, often multiple, by fludrocortisone, or by dihydroergotamine) showed return to normal.

Aged↗
PubMed1990

Effect of posture on plasma atrial natriuretic hormone and renal function during salt loading in patients with and without postural (idiopathic) edema.

The effect of posture on plasma atrial natriuretic hormone (ANH) and renal function was studied in subjects with idiopathic edema. Sixty-five subjects with edema but with no clinical evidence for cardiac, renal, or pulmonary diseases were studied after they had been off all medication for 1 week or more. They had nothing by mouth after midnight and were admitted to the Clinical Research Center at 0800 h. They voided, were weighed, and had their blood pressure and pulse measured in the recumbent and upright positions. A needle was inserted, and subjects were recumbent for 0.5 h, after which blood was drawn for measurement of plasma ANH, serum sodium, potassium, and (in 35 subjects) creatinine. They were then given 150 mL 0.14% sodium chloride solution to drink every 0.5 h for the next 6 h. Urine was collected every 0.5 h for measurement of sodium, potassium, and creatinine. After 4 h of recumbency repeat blood samples were drawn, subjects ambulated for 2 h, after which final repeat blood samples were drawn. Subjects were considered to have postural edema if their upright urinary sodium/previous 2-h urinary sodium was less than 33%, and to have a normal response if it was 33% or more. The clinical characteristics of the 34 patients with postural edema and 31 patients with a normal response were similar. Plasma ANH levels (initial, after oral saline, and after standing) were similar in the two groups, and there was no relationship between changes in ANH and urinary sodium with standing. In conclusion, under conditions of mild oral sodium chloride loading, changes in plasma ANH do not cause the abnormal sodium retention found in patients with postural edema.

Adult↗
PubMed2004

Shape and thickness of cushion in a standing aid to support a forward bending posture: effects on posture, muscle activities and subjective discomfort.

In order to prevent low back pain (LBP) during dishwashing, we developed three types of aid with a thick cushion for supporting the shins and evaluated the effects of the standing aid on the subjective discomfort and muscle activities. Nine female volunteers were asked to wash plates in each of four working postures: (a) without the standing aid, (b) with the round type of aid, (c) with the small rectangular type of aid, and (d) with the large rectangular type of aid. With the three types of aid, the subjects were instructed to support the shins with the standing aid and to support the abdomen with the edge of a kitchen counter. In the three postures with the standing aid, 21.5 +/- 10.0% of the weight was supported with the standing aid and the kitchen counter. The subjective discomfort was milder and the muscle activity level in the low back was lower in the three postures with the standing aid than in the posture without the aid. It was thought that the round type of aid would be more effective in decreasing the discomfort in many of body regions and the muscle load on the low back than either of the rectangular types of aid. Therefore, it was suggested that the standing aid had the desired effect in decreasing discomfort and muscle load on the low back during dishwashing.

Adult↗
PubMed1994

Influence of lateral posture on sweating: does posture alter the sympathetic outflow to the sweat glands?

Our unpublished observation that a lateral decubitus posture influences the pattern of sweating was systematically tested by measuring galvanic skin resistance (GSR). Changes in the GSR between two electrodes placed on skin was used to quantify the degree of sweating. In the lateral posture, sweating is inhibited on the lower half and stimulated on the upper half and reversal of the lateral posture induces sweating on the opposite half of the body. This observation suggests that the autonomic nervous system is controlled at least in part, by body posture.

Adolescent↗