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PubMed1995

A study on the difference of human sensation evaluation to whole-body vibration in sitting and lying postures.

The evaluation of vibration sensation is a problem which has large individual differences. In order to clarify the relationship between posture and psychological response, human sensation to whole-body vibration (from 2 to 11 Hz) in sitting and lying postures was evaluated by the semantic differential method, and the influences of posture on the evaluation were investigated by using the fuzzy measure. Furthermore, the paired t-test was used to test the significant differences in the results of evaluation between the two postures. The results were as follows: (1) Psychological responses of human beings to whole-body vibration were greatly affected by the postures. (2) Changes of the psychological responses in the lying posture were smaller than those in the sitting posture. (3) There were significant differences between sitting and lying postures in the evaluation results of physiological factor, psychological factor and synthetic evaluation (P < 0.025).

Adaptation, Psychological↗

PubMed2001

Postures and repetitive movements during use of a long cane by individuals with visual impairment.

STUDY DESIGN: Descriptive. OBJECTIVE: To describe upper body postures and movements that occur when an individual with visual impairment uses a cane to explore the environment while walking. BACKGROUND: Previous research revealed self-reported neuromusculoskeletal problems related to cane use in individuals with visual impairments. No research, however, is available correlating neuromusculoskeletal problems with specific strategies of cane use or describing what movements and postures actually occur during cane use. METHODS AND MEASURES: Twenty-eight individuals with visual impairment who had been walking independently with a long cane for >1 year were videotaped walking with their canes. Subjects included 16 men and 12 women with a mean age of 39.8 +/- 15.2. Postures and movements of the head and neck, trunk, and each upper extremity body segment were analyzed using videotape. RESULTS: Thirty-nine categories of postures or repetitive joint movements were observed. Half of the subjects lacked intersegmental movement of the head, trunk, and shoulder girdles during walking. The repetitive movements used to manipulate the cane occurred at the forearm or wrist. Intrasubject variability of postures and movements was low. CONCLUSIONS: A variety of sustained postures and repetitive movements occur among individuals using long canes. Each individual displays minimal variability in cane manipulation strategy when walking in an uncomplicated environment. Cane manipulation is accomplished by repetitive movements of wrist flexion/extension, wrist ulnar/radial deviation, or forearm pronation/supination. The remainder of the upper body maintains sustained postures, and more than half of long cane users lack the normal intersegmental movement that typically occurs in the neck, trunk, and shoulder girdle during walking. Further research is needed to determine whether particular cane manipulation strategies or sustained postures during cane use increase the risk of musculoskeletal pain syndromes.

Adolescent↗

PubMed1999

Assessing swine thermal comfort by image analysis of postural behaviors.

Postural behavior is an integral response of animals to complex environmental factors. Huddling, nearly contacting one another on the side, and spreading are common postural behaviors of group-housed animals undergoing cold, comfortable, and warm/hot sensations, respectively. These postural patterns have been routinely used by animal caretakers to assess thermal comfort of the animals and to make according adjustment on the environmental settings or management schemes. This manual adjustment approach, however, has the inherent limitations of daily discontinuity and inconsistency between caretakers in interpretation of the animal comfort behavior. The goal of this project was to explore a novel, automated image analysis system that would assess the thermal comfort of swine and make proper environmental adjustments to enhance animal wellbeing and production efficiency. This paper describes the progress and on-going work toward the achievement of our proposed goal. The feasibility of classifying the thermal comfort state of young pigs by neural network (NN) analysis of their postural images was first examined. It included exploration of using certain feature selections of the postural behavioral images as the input to a three-layer NN that was trained to classify the corresponding thermal comfort state as being cold, comfortable, or warm. The image feature selections, a critical step for the classification, examined in this study included Fourier coefficient (FC), moment (M), perimeter and area (P&A), and combination of M and P&A of the processed binary postural images. The result was positive, with the combination of M and P&A as the input feature to the NN yielding the highest correct classification rate. Subsequent work included the development of hardware and computational algorithms that enable automatic image segmentation, motion detection, and the selection of the behavioral images suitable for use in the classification. Work is in progress to quantify the relationships of postural behavior and physiological responses of pigs using thermographs. The results are expected to facilitate objective training of NN, hence improving the accuracy of the postural image-based assessment of the thermal comfort state. Work is also in progress to implement the analysis and assessment algorithms into computer codes for real-time application.

Animal Welfare↗

PubMed1986

Perception of efforts in working postures.

The aim of this study is to obtain an understanding of the subjective discomfort of working postures and the degree of physical effort these postures give rise to. 31 students have rated their perceived exertion on Borg's scale (1982) based on a collection of photographs of different work postures of varying complexity, including a kinaesthetic description. Each one of the 78 postures was held for 45 seconds, with rated perceived exertion (RPE) given after 15, 30 and 45 seconds. The whole test series was repeated twice. The results show that it is possible to evaluate different body postures by RPE achieving a total reliability alpha-value over 0.96. Despite the fact that the rating pattern between the different postures was the same for all subjects, it is shown that each person assessed according to a certain individually-influenced pattern. A certain person can for example, deviate consistently towards higher values on Borg's scale, a so-called "high rater". Finally, the different postures were grouped according to how the ratings changed in time (regression slope between the RPE's after 15, 30 and 45 seconds). The third-cluster, which showed a high basic rating-level and the greatest regression slope, included only extreme outer limits of movement. This indicates that the outer limit postures have a tendency to static load and need to be studied by more additional methods when remaining unchanged even for short periods.

Adult↗

PubMedDate not supplied

Posture control using electrical stimulation biofeedback: a pilot study.

The investigation studied the effects of biofeedback on the sitting posture of a 14 year old girl with cerebral palsy. The subject's posture was quantified using a video analysis technique which established the threshold of poor posture at 30 degrees from the vertical plane. A stimulator system was designed using an adapted drop foot stimulator and a custom made controller with a mercury tilt switch as the posture angle transducer. If posture became greater than 30 degrees tactile electrical stimulation was administered to the subject's lower back. Repetitive stimuli occurred on non-correction of posture, with a maximum of 4 consecutive stimuli, upon which an alarm was activated. 10 training sessions of 20 min duration were completed over a 4 week period, monitored using a data logger. Following initial improvement the daily results show a gradual deterioration in posture, whilst post-trial video analysis indicates a significant improvement in posture. An improved response to the alarm stimulus is observed. Reasons for these conflicting findings are discussed.

Adolescent↗

PubMed2001

Correlation of unilateral urolithiasis with sleep posture.

PURPOSE: Recurrent stone formers commonly present with calculi on the same side and the etiology of recurrent unilateral urolithiasis is unclear. Despite comprehensive metabolic evaluations, many patients will not be readily categorized into a treatable group. Data from the literature support that sleep posture may result in alterations of renal hemodynamics. We investigate the correlation of sleep posture with unilateral urinary stone formation. MATERIALS AND METHODS: A prospective study of 110 patients with recurrent unilateral nephrolithiasis was conducted. A questionnaire was used to evaluate patient sleep posture. Right or left side down and rotisserie-like sleep postures were defined. The side of stone formation was correlated with sleep posture using chi-square test. RESULTS: Of the patients 93 slept consistently with 1 side in a dependent position and the side of stone was identical to the dependent sleep side in 76% (p = 0.008). The positive predictive values of right and left side down sleep posture for formation of ipsilateral calculi were 82% and 70%, respectively. CONCLUSIONS: Although the exact pathophysiology of the association between sleep posture and recurrent unilateral stone disease remains to be elucidated, sleep posture may alter renal hemodynamics during sleep and promote stone formation. This observation needs further investigation and should be factored into the evaluation and prevention of unilateral urinary stone disease.

Adult↗

PubMed2003

Lumbar paraspinal muscle function, perception of lumbar position, and postural control in disc herniation-related back pain.

STUDY DESIGN: A follow-up study evaluating postural control, lumbar movement perception, and paraspinal muscle reflexes in disc herniation-related chronic low back pain (LBP) before and after discectomy. OBJECTIVES: To assess the effect of discectomy on postural control, lumbar perception, and reflex activation of paraspinal muscles during sudden upper limb loading. SUMMARY OF BACKGROUND DATA: Impaired muscle function, postural control, and lumbar proprioception have been observed in LBP. However, they have not been studied in sciatica patients after surgery. METHODS: The study included 20 patients selected for an operation for chronic LBP caused by disc herniation and 15 controls without chronic LBP. The paraspinal muscle responses for upper limb loading during unexpected and expected conditions were measured by surface electromyography. The ability to sense lumbar rotation was assessed in a previously validated motorized trunk rotation unit in the seated position. The postural control was measured with a vertical force platform. Pain, disability, and depression scores were recorded. RESULTS: Patients had poorer lumbar perception (P = 0.012) and postural control (P < 0.05) than did healthy controls. The postural control remained unchanged, but lumbar perception (P = 0.054) and the lumbar feed-forward control (P = 0.043) improved after the surgery. CONCLUSIONS: The results demonstrate impaired lumbar proprioception and postural control in sciatica patients. During short-term follow-up after operative treatment, postural control does not seem to change, but impaired lumbar proprioception and feed-forward control of paraspinal muscles seem to recover.

Chronic Disease↗

PubMed1989

Postural patterns of farmers in the Ryukyu Islands.

Postural patterns in everyday life were observed in the Ryukyu Islands. Postures seem to have two dimensions. In one dimension, they consciously changed their posture in the same action according to situations. In the other dimension, they took a particular posture, e.g., sitting with one knee raised, in different actions. The former may be related to the communicative aspect of posture, while the latter to the technical aspect of posture. Further, some postures, e.g., standing while deeply bending forward, could be regarded as techniques peculiar to their culture. The relation between culture and biology is also discussed with respect to postural patterns which may be related to the traditional lifestyle in Okinawa.

Activities of Daily Living↗

PubMed1995

Epidural pressure measurements. Relationship between epidural pressure and posture in patients with lumbar spinal stenosis.

STUDY DESIGN: The relationship between epidural pressure and lumbar posture was assessed in patients with lumbar spinal stenosis. OBJECTIVES: This study was performed to assess the relationship between epidural pressure and lumbar posture in patients with lumbar spinal stenosis. METHODS: The study was performed on 10 patients who had cauda equina symptoms at the L4-L5 level. The catheter transducer was inserted into the epidural space through L5-S1 interlaminar space and placed at the L4-L5 disc level. This transducer was connected with an amplifier and a recorder. Epidural pressure was continuously measured in various postures. RESULTS: Local epidural pressure at the stenotic level was low in lying and sitting postures, and high in standing postures. Pressure was increased with extension, but decreased with flexion. The highest pressure was 116.7 +/- 38.4 mm Hg in standing with extension. CONCLUSION: Epidural pressure was significantly related to posture. These pressure changes correlated with the development of cauda equina symptoms. The increase of epidural pressure by posture may induce compression of the cauda equina. These pressure changes may explain the postural dependency in eliciting symptoms.

Aged↗

PubMed1994

[Postural disorders in children and adolescents].

Posture is defined as the upright well balanced position of an individual person. A postural fault is a posture that deviates from normal alignment without structural limitations. Postural faults are established in adolescence causing pain syndromes in adulthood. Major components of spinal structure and function are reviewed. The dynamics of posture are described. Characteristics and etiology of common postural faults in childhood and adolescence are characterised. Based on standardised diagnostic techniques, principles of how to manage posture and treatment of postural dysfunctions are discussed.

Adolescent↗

PubMed1993

Development of posture in the rat.

Postural development has not attracted much attention in investigations of neuro-ontogeny. In the rat, motor behaviours have been studied repeatedly but the development of postural control has been largely neglected. In the present study we have taken inventory of behavioural aspects of postural development. Postures and postural skills of 10 pups were 3-dimensionally recorded on video tape from the 2nd to the 20th day. The development of posture may be subdivided into three periods. During the first period, lasting until the 4th or 5th day, neonates were unable to lift their trunk from the floor, and the only indication for postural activity being head lifting. From then until the 12th-13th day, pups were able to walk, though staggering, and in addition they groomed and reared with forelimb support. From then, in a rapid development lasting until day 16, the adult type of fluent locomotion developed as well as grooming and rearing without support. In addition, complex motor acts developed. These results are discussed in the perspective of the structural and functional development of postural systems.

Animals↗

PubMed1993

Visual stabilization of posture in retinitis pigmentosa and in artificially restricted visual fields.

PURPOSE: To investigate the relationship between retinitis pigmentosa (RP) progression and the visual contribution to posture stabilization; to examine the extent to which visual-field diameter affects the visual contribution to posture stabilization. METHODS: Posture information was recorded in 35 subjects with well-characterized RP and in 20 subjects with normal vision. Data were collected as each subject stood in a dark environment and as each subject viewed a stationary visual display. In both conditions, somatosensory feedback was concurrently altered. Data were also collected on 10 additional subjects with normal vision wearing field-restricting goggles (visual-field diameters ranged from 26.5 down to 6 degrees). RESULTS: RP progression is accompanied by a steady decrease of the visual stabilization of posture, from normal values at the onset of the disease to the absence of visual stabilization and, eventually, to visual destabilization of posture. Decreasing visual field diameter in the subject with normal vision resulted in a linear decrease of the visual stabilization of posture. However, subjects with RP with comparable visual-field loss showed significantly lower visual stabilization than normal subjects with artificially restricted fields. Moreover, subjects with normal vision with restricted visual fields as small as 6 degrees failed to show visual destabilization of posture. CONCLUSIONS: Most likely, the additional reduction in the visual stabilization of posture shown in subjects with RP, as well as the visual destabilizing effect manifest in the late stages of RP, is caused by anomalous processing of visual information in the remaining visual field.

Adult↗

PubMed1993

[Posture in preterm infants is not a good indicator of brain damage].

The development of posture during the prenatal period was studied longitudinally in 12 matched pairs of low-risk and high-risk preterm infants. The gestational age of the infants in both groups ranged from 28 to 36 weeks. The two members of each pair had the same gestational age at birth and the video recordings were performed at the same postmenstrual age. They were filmed more than three times during the prenatal period, each video recording lasting 1 h. Time of occurrence and duration of each posture were analyzed from replay of the video recordings. No age-specific preference posture described in the literature was found from birth until the term age between two groups. There was no age-related tendency in duration and frequency of postures between two groups. There was a clear-cut dominant head position to the right side from 31 weeks onward. Asymmetrical tonic neck postures (ATN) were very inconsistently present before the term age. And there was no significant difference in the occurrence of ATN postures between two groups. We could not find any specific abnormal postures in the high-risk group. Our study suggested that posture in preterm infants is not a good indicator of brain damage in the prenatal period.

Brain Injuries↗

PubMed1993

Postural force fields of the human arm and their role in generating multijoint movements.

When a perturbation displaces the human hand from equilibrium, arm muscles respond by producing restoring forces. When a set of displacements are given at various directions from the same equilibrium position, the resulting restoring forces form a "postural force field." It is not known whether these postural forces are related to those generated when a reaching movement is executed. However, if a movement is a consequence of a shift of the equilibrium position of the hand toward the target, then, from the postural force field, predictions can be made regarding the nature of the elastic forces acting on the hand during the movement. We have taken the first steps in testing this hypothesis by measuring the postural force field of a subject's arm over relatively large distances, and comparing these forces with the static forces generated at the hand while the subject attempted a reaching movement. Using a robot manipulandum, the hand was displaced at various directions from an equilibrium position. The measured restoring forces were fitted to a nonlinear model to define a postural force field for that equilibrium position. This field was used to predict elastic forces generated when the subject attempted to move the manipulandum from a point on the circumference of a circle to a target at its center--the center corresponded to the equilibrium position at which the postural field was measured. In some of the movement trials, the manipulandum was locked during approximately the first 120 msec of the program for motion and the resulting static "evoked" forces measured. We found that (1) the evoked forces did not point to the target, but were a function of the configuration of the arm and rotated with the shoulder joint, and (2) the magnitude of the evoked forces varied systematically, even though the movements were of the same magnitude. These patterns were remarkably similar to those observed in the postural forces. Our results provide experimental evidence linking maintenance of posture in a multijoint system to that of generating a movement. The evidence is consistent with the hypothesis that the CNS programs a reaching movement by shifting the equilibrium position of the hand toward the target.

Adult↗

PubMed1998

[Stereovideographic evaluation of the postural geometry of healthy and scoliotic patients].

Idiopathic scoliosis principally characterised by a deformation of the vertebral column can also be associated to postural abnormalities. The validity and reliability of current quantitative postural evaluations has not been thoroughly documented, frequently limited by a two dimensional view of the patient, and do not include the whole posture of the patient. The purpose of this study is to 1) quantify within and between-session reliability of a stereovideographic Postural Geometry (PG) evaluation and 2) to investigate the sensitivity of this technique for the postural evaluation of scoliosis patients. The PG of 14 control subjects and 9 untreated scoliosis patients were evaluated with 5 repeat trials, on two occasions. Postural geometry parameters that describe the position and orientation of the pelvis, trunk, scapular girdle and head were calculated based on the 3-dimensional co-ordinates of anatomical landmarks. The mean between and within-session variability across all parameters were 12.5 mm, 2.8 degrees and 5.4 mm and 1.4 degrees respectively. The patient group was heterogeneous with some noted pathological characteristics. This global stereovideographic postural geometry evaluation appears to demonstrate sufficient reliability and sensitivity to follow-up on the posture of scoliosis patients.

Adolescent↗

PubMed1998

The postural stability control and gait pattern of idiopathic scoliosis adolescents.

OBJECTIVE: The static postural equilibrium and gait patterns between idiopathic scoliotic (IS) patients and normal subjects were studied to verify the best method to identify the functional disability in IS patients. DESIGN: The static stability in six postures and gait patterns among normal subjects and IS patients were compared. BACKGROUND: Postural stability control and gait analysis are non-invasive methods to identify many diseases. However, the dysfunction of IS patients in postural stability control and gait pattern is not clear. The results of this research may lead to further understanding of the etiology of idiopathic scoliosis in the postural equilibrium influencing aspects. METHODS: Thirty IS patients and fifteen normal subjects were recruited for postural stability control test and gait analysis using the force plate and 3-D motion analysis system. RESULTS: The IS patients generally produced higher sway area, lateral sway, sagittal sway, and sway radius than normal subjects. The cadence is smaller in the IS patients, but the stance phase and stride phase are similar to normal subjects. CONCLUSIONS: The IS patients are poor in postural stability control but their gait pattern is similar to that of normal subjects. Standing with trunk at full flexion is the most effective position to identify the postural stability control of IS patient.

Journal Article↗

PubMed1998

Abnormal head posture associated with high hyperopia.

BACKGROUND: An abnormal head posture may be adopted for ocular or nonocular reasons. The most common ocular reasons are to maintain binocularity and to obtain the best possible visual acuity. Patients with undercorrected or overcorrected refractive errors have been reported to adopt a variety of head positions, thought to be an attempt to obtain the best possible visual acuity. METHODS: Five patients with symmetric high hyperopia (at least + 5.00 D) and an abnormal head posture are presented. RESULTS: All five patients demonstrated an abnormal head posture of chin down for fixation without the spectacle correction in place. This abnormal head posture was eliminated by occlusion of either eye and also by wearing of the refractive correction. No patient demonstrated significant strabismus. CONCLUSION: An abnormal head posture when not wearing spectacle correction can occur in children who have high hyperopia and insignificant strabismus. This may be a mechanism by which the best visual acuity is obtained (indicated by the disappearance of the abnormal head posture on wearing of the glasses) and also to maintain binocularity (indicated by the disappearance of the abnormal head posture under monocular testing conditions). The presence of a chin-down abnormal head posture should alert the examiner to the possible presence of high hyperopia and therefore the necessity for a cycloplegic refraction.

Child↗

PubMed1992

Self-sitting and reaching in 5- to 8-month-old infants: the impact of posture and its development on early eye-hand coordination.

The relation between progress in the control of posture (i.e., the achievement of self-sitting posture) and the developmental transition from two-handed to one-handed engagement in infant reaching was investigated. Two groups of 5- to 8-month-old infants, who were either able or yet unable to sit on their own, were videotaped while they reached for objects in four different posture conditions that provided varying amounts of body support. Videotapes of infant reaches were microanalyzed to determine the relative engagement of both hands during reaches. Results demonstrate the interaction between postural development and the morphology of infant reaching. Nonsitting infants displayed symmetrical and synergistic engagement of both arms and hands while reaching in all but the seated posture condition. Sitting infants, by contrast, showed asymmetrical and lateralized (one-handed) reaches in all posture conditions. Results also show that, aside from posture, the perceived spatial arrangement of the object display is a determinant of infant reaching. Combined, these results are discussed as evidence for the interaction between postural and perceptual development in the control of early eye-hand coordination.

Journal Article↗