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PubMed1984

Elderly inpatients: postural reflex impairment.

We examined postural reflexes in 50 patients in a geriatric care facility. Patients aged 60 years and older who did not have orthostatic hypotension were subjected to a standing postural perturbation, and the degree of postural instability was recorded. Sixteen patients with leg amputations, recent stroke, and leg deformities were excluded. Of the remaining 34 patients, 44% had severe postural reflex impairment, and 24% had moderate impairment. Although the etiology for postural reflex impairment may be multivariant, the high percentage suggests that postural reflex dysfunction may be an important cause of unexplained falls in the elderly.

Aged↗
PubMed2004

The delay of gastric emptying induced by remifentanil is not influenced by posture.

Posture has an effect on gastric emptying. In this study, we investigated whether posture influences the delay in gastric emptying induced by opioid analgesics. Ten healthy male subjects underwent 4 gastric emptying studies with the acetaminophen method. On two occasions the subjects were given a continuous infusion of remifentanil (0.2 microg. kg(-1). min(-1)) while lying either on the right lateral side in a 20 degrees head-up position or on the left lateral side in a 20 degrees head-down position. On two other occasions no infusion was given, and the subjects were studied lying in the two positions. When remifentanil was given, there were no significant differences between the two postures in maximal acetaminophen concentration (right side, 34 micromol. L(-1); versus left side, 16 micromol. L(-1)), time taken to reach the maximal concentration (94 versus 109 min), or area under the serum acetaminophen concentration time curve from 0 to 60 min (962 versus 197 min. micromol. L(-1)). In the control situation, there were differences between the postures in maximal acetaminophen concentration (138 versus 94 micromol. L(-1); P < 0.0001) and area under the serum acetaminophen concentration time curves from 0 to 60 min (5092 versus 3793 min. micromol. L(-1); P < 0.0001), but there was no significant difference in time taken to reach the maximal concentration (25 versus 47 min). Compared with the control situation, remifentanil delayed gastric emptying in both postures. We conclude that remifentanil delays gastric emptying and that this delay is not influenced by posture.

Acetaminophen↗
PubMed2005

Laboratory measurement of posture allocation and physical activity in children.

PURPOSE: The purpose of this study was to validate the combined use of inclinometers and accelerometers to measure body posture and movement in children in a laboratory setting. METHODS: We performed two separate experiments. In the first experiment, we tested the hypothesis that four inclinometers (tilt sensors) could be used to capture body posture in children. We observed and recorded body posture in eight healthy children (mean +/- SD; body mass index (BMI), 18 +/- 3 kg x m(-2)) on 2880 occasions and compared these records with the inclinometer data. In the second experiment, the hypothesis was that two inclinometers could be used to determine whether 18 children (BMI, 21 +/- 5 kg x m(-2)) were sedentary. We observed and recorded sedentariness (sitting/lying compared to standing) on 5575 occasions and compared these records with the inclinometer data. In both of these experiments, we also addressed the hypothesis that accelerometer output, when measured at varying velocities, correlated with walking energy expenditure. RESULTS: In experiment 1, body posture was correctly identified in 2880 out of 2880 inclinometer measurements. In experiment 2, sedentary behavior was correctly identified in 5575 out of 5575 occasions. For the entire group, acceleration and body weight correlated well with energy expenditure (r2 = 0.84). CONCLUSION: The inclinometer-accelerometer system that we tested can be used to measure body posture and movement. We can measure sedentary behavior using two inclinometers instead of four inclinometers. This monitoring system may be useful for measuring energy expenditure, body posture, and physical activity in children.

Calorimetry, Indirect↗
PubMed2002

Onset of dyskinesia and changes in postural task performance during the course of neuroleptic withdrawal.

The effect of neuroleptic withdrawal on postural task performance of 20 adults with mental retardation was examined. Dyskinesia was measured using the DISCUS rating scale and postural stability using a force platform during a prospective longitudinal neuroleptic medication withdrawal protocol. Assessments were conducted at baseline and monthly intervals, extending to approximately one year following complete medication withdrawal, when significant changes in amount of postural motion and sequential pattern of postural movement complexity were observed. Postural task performance tended to return to near baseline levels at periods of up to 1 year following medication withdrawal, although one third of the subjects continued to display atypical postural motion profiles at follow-up. Results provide within-subject evidence that tardive dyskinesia is associated with generalized changes in motor control and not simply peripheral disturbances of movement.

Adult↗
PubMed1996

Effect of jaw position and posture on forced inspiratory airflow in normal subjects and patients with obstructive sleep apnea.

OBJECTIVE: This study evaluated whether substantial airflow changes occur by changing both body posture and jaw position in normal subjects and patients with obstructive sleep apnea (OSA). DESIGN: A case-control design was utilized to assess group differences (OSA vs control) and each subject served as his/her own control subject to assess condition differences (jaw position and body posture changes). Subjects included 16 male patients with OSA (aged 33 to 71 years) whose conditions were diagnosed at the UCLA Sleep Disorders Laboratory with a polysomnographic recording, and 9 male non-OSA subjects (aged 22 to 52 years). The experimental intervention in the study involved alterations in body posture and jaw positioning. Airflow changes were determined using a spirometer that assessed the velocity of airflow during a forced inspiration. Subjects in this study all had the middle portion (25 to 75%) of their maximum forced inspiratory flow (FIF25-75) curve measured in three positions; (1) normal jaw position-upright body posture (N-U); (2) normal jaw position-supine body posture (N-S); and (3) protrusive jaw position-supine body posture (P-S). SETTING: The study was conducted at the UCLA Dental Clinical Research Center. RESULTS: Both groups had a significant decrease in their FIF25-75 upon reclining, and there were no significant group differences regarding the magnitude of this change. Both groups also had a nearly full recovery of their FIF25-75 airflow when their jaws were positioned forward while reclining. CONCLUSIONS: These data document that when a patient is in a supine position, a 100% protrusive jaw position allows significantly more inspiratory airflow to occur.

Adult↗
PubMed1996

Postural variations of pulmonary diffusing capacity in insulin-dependent diabetes mellitus.

STUDY OBJECTIVE: To assess whether posture-related changes of diffusing capacity could be considered as an early sensitive marker of pulmonary abnormalities in patients with insulin-dependent diabetes mellitus (IDDM) and whether the postural variations of pulmonary capillary blood volume (Vc) could reflect the lung capillary damage that characterizes the diabetic microangiopathy. DESIGN: Carbon monoxide diffusing capacity (DCO) was measured by the single-breath method. Four DCO measurements, two in sitting and two in supine position, were performed in each subject using gas mixtures containing different oxygen concentrations. Membrane and capillary volume components of the diffusion capacity were calculated and both were expressed as absolute value and corrected by alveolar volume (VA). PATIENTS: Twenty IDDM patients and 20 normal subjects matched for age and sex were studied. MEASUREMENTS AND RESULTS: The IDDM patients showed normal pulmonary volumes and flows. No significant differences between the two groups were found for DCO, coefficient of diffusion, Vc, and pulmonary capillary blood volume corrected by alveolar volume in sitting position. All these indexes significantly increased in normal subjects but not in diabetics, by changing the posture of the subject from sitting to supine position. In a multivariate analysis, the presence of diabetes mellitus and the age of the subjects were the only significant predictors of Vc postural changes. CONCLUSIONS: This postural test, adjusted for age, could be included in a screening diagnostic procedure for an early assessment of pulmonary abnormalities in diabetic patients. The lack of Vc postural increase in diabetics could reflect the presence of a microangiopathy involving the pulmonary small vessels.

Adult↗
PubMed2000

Usefulness of posture training for patients with temporomandibular disorders.

BACKGROUND: Many practitioners have found that posture training has a positive impact on temporomandibular, or TMD, symptoms. The authors conducted a study to evaluate its effectiveness. METHODS: Sixty patients with TMD and a primary muscle disorder were randomized into two groups: one group received posture training and TMD self-management instructions while the control group received TMD self-management instructions only. Four weeks after the study began, the authors reexamined the subjects for changes in symptoms, pain-free opening and pressure algometer pain thresholds. In addition, pretreatment and posttreatment posture measurements were recorded for subjects in the treatment group. RESULTS: Statistically significant improvement was demonstrated by the modified symptom severity index, maximum pain-free opening and pressure algometer threshold measurements, as well as by the subjects' perceived TMD and neck symptoms. Subjects in the treatment group reported having experienced a mean reduction in TMD and neck symptoms of 41.9 and 38.2 percent, respectively, while subjects in the control group reported a mean reduction in these symptoms of 8.1 and 9.3 percent. Within the treatment group, the authors found significant correlations between improvements in TMD symptoms and improvements in neck symptoms (P < .005) as well as between TMD symptom improvement and the difference between head and shoulder posture measurements at the outset of treatment (P < .05). CONCLUSIONS: Posture training and TMD self-management instructions are significantly more effective than TMD self-management instructions alone for patients with TMD who have a primary muscle disorder. PRACTICE IMPLICATIONS: Patients with TMD who hold their heads farther forward relative to the shoulders have a high probability of experiencing symptom improvement as a result of posture training and being provided with selfmanagement instructions.

Adolescent↗
PubMed2006

Analysis of an observational rating scale for repetition, posture, and force in selected manufacturing settings.

OBJECTIVE: The aim of this work was to quantify the interrater reliability of a set of scales that assess repetition, posture, and force as used on site when examining industrial work. BACKGROUND: Interrater reliability of observational assessment methods can vary depending on the definition of the methods and situations in which they are used. METHOD: In several industries, 846 jobs were assessed using pairs of analysts to rate the repetition, force, and posture of the upper limbs. Twelve analysts with varying experience levels participated. RESULTS: Using an interclass correlation coefficient (ICC), force and repetition had reliability values of .60 and .71 before and .82 and .87 after discussion, respectively. After discussion, peak posture ratings had ICCs of .60 to .83. ICCs for average posture ratings ranged from .31 to .51 initially to .55 to .67 in final ratings. Less experienced analysts changed their initial ratings more than did the senior investigators. CONCLUSION: The high interrater reliability of the repetition and force metrics indicates that a single analyst is appropriate for basic job assessment. Posture ratings benefit greatly from a two-analyst system. Average postures should be assessed across a full range of the scale for interrater reliability assessment. Analyst pairs should be rotated to avoid forming biases. APPLICATION: For basic assessments of forceful exertions and repetitive motions, a single analyst can be used, reducing the resource requirements for both industry and large epidemiological studies.

Humans↗
PubMed1997

Task effects on three-dimensional dynamic postures during seated reaching movements: an investigative scheme and illustration.

In this paper we describe a new scheme for empirically investigating the effects of task factors on three-dimensional (3D) dynamic postures during seated reaching movements. The scheme relies on an underlying model that integrates two statistical procedures: (a) a regression description of the relationship between the time-varying hand location and postural angles to characterize the movement data and (b) a series of analyses of variance to test the hypothesized task effects using representative instantaneous postures. The use of this scheme is illustrated by an experiment that examines two generic task factors: hand motion direction and motion completion time. Results suggest that hand motion direction is a significant task factor in determining instantaneous postures, whereas a distinctive difference in the time to complete a motion does not appear to have a significant effect. We discuss the concept of an instantaneous posture and its utility in dynamic studies of movements, some insights into human reaching movement control strategy, and implications for the development of a 3D dynamic posture prediction model.

Adult↗
PubMed1991

[Development of posture measuring apparatus using goniometer and inclinometer. 1. Description of the apparatus and its usefulness].

A new posture measuring apparatus was developed for time and motion study in the field of industrial health. This apparatus can record and classify working postures by measuring the angles of joints and trunk inclination. The angles of joints are measured by newly developed goniometers which use the bending loss of rubber optical fibers. The trunk inclination is measured by an inclinometer which uses photointerrupters. The measured angle data stored in the memory of this apparatus are transferred to the host computer and analyzed. Postures are classified automatically and subjectively according to discriminant functions which are calculated from the preliminarily measured data by discriminant analysis. Test measurement was carried out to classify four postures; standing, forward bending, half sitting and sitting. The goniometers were set on the right hip joint, knee joint, and ankle joint and the inclinometer was set on the right side of the trunk. The postures were changed in the order of standing, forward bending, half sitting, and sitting every 30 s. The angles were measured every second and a total of 120 sets of angles were measured. All data including data during posture changing were classified correctly by discriminant functions. The measurement during baggage lifting up and putting down was also carried out. Ten baggages (each 7 kg in weight) were lifted up from the floor onto a desk (75 cm in height), put down back to the floor, and again lifted on the desk. In 2 min, baggages were lifted up for a total of 20 times and put down for a total of 10 times.(ABSTRACT TRUNCATED AT 250 WORDS)

Discriminant Analysis↗
PubMed2006

Pharmacokinetics of pyridostigmine in a child with postural tachycardia syndrome.

Pyridostigmine has been proposed for the treatment of postural orthostatic tachycardia syndrome in adults at a dose of 60 mg twice daily, but no dosing recommendation exists for children. With the approval of our local ethics board, we tested the pharmacokinetics of pyridostigmine in 6 children with myasthenia and a pediatric index patient with severe postural orthostatic tachycardia syndrome whose condition failed all conventional therapy and who had developed significant postural hypertension. Pyridostigmine was quantified by using a validated, semiautomated, and specific high-performance liquid chromatography/tandem mass spectrometry assay in combination with online column-switching extraction and turbo electrospray ionization. The patient with postural orthostatic tachycardia syndrome showed a dose-dependent favorable response to oral pyridostigmine. Pharmacokinetic evaluation revealed a short half-life of 2.29 hours, similar to the 2.0 +/- 0.63 hours in the patients with myasthenia. The patient with postural orthostatic tachycardia syndrome has subsequently been treated at a dose of 45 mg in the morning, 30 mg at lunchtime, and 15 mg at bedtime; after 9 months, there has been persistent positive effect and without additional blood pressure medication. No major adverse effects occurred. Pyridostigmine has been a safe and effective treatment modality for this child with postural orthostatic tachycardia syndrome. The short half-life suggests that dosing 3 times per day is preferable.

Adolescent↗
PubMed1994

[Thermal insulation of clothing for seated and standing postures].

The purpose of this study is to examine the effects of body posture on thermal insulation of clothing. Clothing ensembles including skirts were mainly investigated. A new thermal manikin was developed for this study. This manikin was able to change her body posture without increasing or decreasing her surface area. By changing posture from standing to seated, the total thermal insulation of clothing (It) was decreased by around 1.4%. The surface thermal resistance at nude (Ia) was increased by 8%. As a result, the basic thermal insulation of clothing (Icl) was decreased by 14%. The main reason for the decrease of basic thermal insulation (Icl) when the posture of thermal manikin changes from standing to seated was the increase of Ia at nude. The total thermal insulation of clothing for each body posture (Iti), when standing and seated, were compared. The parts affected by the changed posture were abdomen, hip and thighs, and especially under the skirt of 61cm length, the knees were most affected.

Adult↗
PubMed2005

The effects of an attentional demand tasks on standing posture control.

The present study sought to determine if the postural sway of a subject required to grasp a tray (motor task) holding a cup filled with water and prevent spilling (mental task), would be reduced by consciously redirecting attention to maintain the tray in a horizontal position. We hypothesized the mental task would increase the stabilization of standing postural balance. Postural sway was measured in 17 normal subjects under the following conditions: 1) holding a 100 g weight in each hand (total 200 g; no mental task), 2) holding with both hands a tray on which 200 g was placed (tray-holding task), and 3) holding with both hands a tray on which a cup filled with water weighing 200 g was placed in the center (mental task). Postural sway was significantly reduced during the mental task versus other tasks. Standing posture balance was stabilized when a mental task was added. Thus, we concluded that higher brain functions such as attention and consciousness exerted a significant influence over the control of standing posture.

Adult↗
PubMed1996

Postural control under clinorotation in upside-down catfish, Synodontis nigriventris.

The upside-down catfish Synodontis nigriventris has a unique habit of swimming and resting upside-down in free water. This behavior leads to the assumption that the catfish has a specific gravity information processing system. We examined the postural control behaviors in the catfish under clinorotation which is usually used for producing pseudo-microgravity. Synodontis nigriventris kept its body posture at a stable area of the rotated flask in which the catfish was kept, when it was clinorotated at the rate of 60 rpm. In contrast to Synodontis nigriventris, a related species, Corydoras paleatus, did not show such steady postural control. When the flask was rotated at a lower rate of 30 rpm or a higher rate of 100 rpm, Synodontis nigriventris as well as Corydoras paleatus showed a considerable disturbed control of body posture. In this condition, they were frequently rotated with the flask. These findings suggest that Synodontis nigriventris has a high ability to keep upside-down posture and the gravity sensation in this catfish is likely to contribute to its different postural control from that of many other fishes.

Animals↗
PubMed1994

Postural instability in patients with diabetic sensory neuropathy.

OBJECTIVE: Recent survey evidence suggests that sensory ataxia due to diabetic neuropathy may be a more frequent and serious problem than is commonly recognized. This view is further supported by research that confirms the major contribution of the somatosensory system to the control of posture. We therefore sought to determine the effects of significant diabetic distal symmetrical polyneuropathy on the control of posture. RESEARCH DESIGN AND METHODS: Fifty-one subjects, divided into three groups, participated in this study. Seventeen had diabetes and significant sensory neuropathy, 17 had diabetes and no neuropathy, and 17 had neither diabetes nor neuropathy. The subjects were matched across groups, and stringent exclusion criteria were applied. Postural stability during quiet standing was measured using a force platform. In addition to electrophysiological and quantitative sensory tests of neuropathy, a number of physical and functional characteristics were measured for all subjects. RESULTS: Postural instability was found to be significantly associated with sensory neuropathy, but not with diabetes per se. Patients with sensory neuropathy demonstrated between 66 and 117% more instability than did control subjects (depending on the testing condition). Based on multiple linear regression analyses, the most significant correlates of instability were the quantitative sensory measures of neuropathy and age. CONCLUSIONS: The loss of sensory perception secondary to diabetic distal symmetrical sensory neuropathy has a markedly detrimental effect on postural stability. The deficit is greatest when visual or vestibular cues are absent or degraded. Patients with neuropathy need to be informed of the postural consequences of this condition to limit the potential morbidity caused by falls.

Aging↗
PubMed1991

The effect of postural change and upper respiratory tract infection on middle ear pressure.

The effect of a change in posture from sitting erect to lying supine and horizontal on middle ear pressure was investigated in 5 healthy adults and 5 adults with symptoms of an acute upper respiratory tract infection (URTI). The change in posture had no significant effect on middle ear pressure in the healthy subjects (p greater than 0.05). In those with URTI mean middle ear pressure increased from -39.5 daPa (erect) to -16.9 daPa (supine) (p = 0.026, n = 10). In the supine posture the middle ear pressure in subjects with URTI was raised. The cause of the increase in middle ear pressure is discussed in terms that the postural change may alter middle ear physiology such that in the supine posture there is a net production of middle ear gas as opposed to a net reabsorption in the erect posture. This may indicate that an increase in jugular venous pressure causes a net positive production of middle ear gas.

Acoustic Impedance Tests↗
PubMed2005

Dual-task training reduces impact of cognitive task on postural sway.

Postural sway increases when a cognitive task is performed concurrently with a postural task. The author examined the hypothesis that following dual-task training, a concurrent cognitive task would not amplify postural sway. Participants (N = 18) were assigned to no-training, single-task training, or dual-task training groups. Single-task training consisted of 3 sessions in which the postural task, quiet standing on a compliant surface, and the cognitive task, counting backward by 3s, were practiced separately. Dual-task training consisted of 3 sessions of concurrent practice of the cognitive and postural tasks. After training, performance of a concurrent cognitive task increased postural sway in the no-training and single-task training groups but not in the dual-task training group. Results suggest that dual-task practice improves dual-task performance.

Adolescent↗
PubMed1993

The effects of background visual roll stimulation on postural and manual control and self-motion perception.

The effects of background visual roll stimulation on postural control, manual control, and self-motion perception were investigated in this study. In the main experiment, 8 subjects were exposed to wide field-of-view background scenes that were tilted and static, continuously rotating, or sinusoidally rotating at frequencies between 0.03 and 0.50 Hz, as well as a baseline condition. The subjects performed either a postural control task (maintain an upright stance) or a manual control task (keep an unstable central display horizontally level). Root-mean square (RMS) error in both the postural and manual control tasks was low in the static tilt condition and extremely high in response to continuous rotation. Although the phases of the postural and manual responses were highly similar, the power and RMS error generated by the sinusoidal visual background stimulation peaked at a lower frequency in the postural task. Vection ratings recorded at the end of the postural and manual trials somewhat paralleled the frequency tuning differences between tasks, which a subsequent experiment showed to be the result of the differential motion of the central display rather than the differential positioning of the subject. In general, these results show that the dynamic characteristics of visual orientation systems vary according to the specific motor and/or perceptual system investigated.

Adult↗