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PubMed1990

Continuous positive airway pressure breathing in supine and upright postures.

Continuous positive airway pressure (CPAP) breathing of 10 cmH2O was applied to 10 healthy conscious subjects both in supine and 70 degree head-up postures. CPAP increased the end-expiratory lung volume from 2.44 +/- 0.66 (S.D.) to 3.07 +/- 0.68 liters in supine subjects, and from 3.01 +/- 0.57 to 3.64 +/- 0.57 liters in head-up subjects. During CPAP, rib cage motion became predominant when compared to abdominal motion in upright posture. Among the respiratory parameters, inspiratory duration was significantly shortened during CPAP in either posture, but was changed less significantly by individual posture change alone. Mean inspiratory flow decreased during CPAP only in upright posture. Abdominal muscles were recruited for expiration during CPAP in either posture, and the EMG recorded from the lower intercostal space developed inspiratory activity during CPAP in head-up posture. All of 10 subjects felt most dyspneic during CPAP with the head-up. We conclude that the mechanism of increase in lung volume during CPAP is mediated by different pathway from that of posture change, and that CPAP in upright posture can alter the respiratory pattern of the subject.

Adult↗

PubMed2004

Reliability and validity of classification of senile postural deformity in mass examinations.

Nakada (1988) divided senile postural deformities into four types by visual observation: an extended type, an S-shaped type, a flexed type, and a hand-on-the-lap type. The purpose of this study was to investigate the inter-rater reliability and the discriminant validity of assessing the elderly spinal posture using a posture-measuring device developed by us and dividing postural deformities into the four types of Nakada's classification. Seventy-seven elderly persons (52 women and 25 men) who lived independently participated in the study. The average age of the subjects was 73 years (range, 65 to 84 years). The type of the senile postural deformity was determined by three judges using our posture-measuring device in combination with Nakada's classification. The rate of agreement of the classification was 92.2%. This method had a significantly high rate of inter-rater reliability. The thoracic kyphotic angle was larger in the S-shaped type than in the normal, extended type, and flexed type. The lumbar lordotic angle was also larger in the S-shaped type than in the extended type, flexed type, and hand-on-the-lap type. In the hand-on-the-lap type, the mean of the lumbar lordotic angle was much smaller. The lumbosacral angle was smaller in the extended type than in the normal, S-shaped type, and flexed type. With the analysis of x-ray photographs, this method appeared to have discriminant validity as a measure of senile postural deformity. The combination of our posture-measuring device and Nakada's classification would be useful to classify senile postural deformities in mass examinations.

Aged↗

PubMed1996

Relationship between frequency of upside-down posture and space size around upside-down catfish, Synodontis nigriventris.

The catfish Synodontis nigriventris shows a unique habit taking a stable upside-down posture in free water regardless of an above, one-sided illumination. This upside-down posture can be observed when the catfish is apart from objects because the catfish usually orients its ventral side towards the water bottom or objects due to a so-called ventral substrate response. Thus, it is not easy to study the mechanism of the upside-down posture. To resolve this problem, the frequency of the upside-down posture was measured by using various sizes of vessel in which the catfish was kept. Video analysis showed that the frequency of the upside-down posture depended on the space size around the catfish. The smaller the size became, the higher the frequency of the upside-down posture became. Furthermore, the frequency of the upside-down posture depended on the shape of the vessel bottom. Curved-bottom vessels induced the upside-down posture more frequently than flat bottom. These findings suggest that a small, curved-bottom vessel is ideal for researching the upside-down postural control mechanism.

Animals↗

PubMed1998

An analysis of posture and back pain in the first and third trimesters of pregnancy.

While the incidence of back pain during pregnancy has been shown to be high, few studies have investigated postural changes that occur during pregnancy and their relationship to back pain. The purpose of this study was to determine if posture and back pain changed from the first to the third trimester of pregnancy and whether there was a relationship between the two. Twelve healthy women who were having uncomplicated pregnancies participated in the study. During the first and third trimesters, each subject had their standing posture and back pain assessed by a Metrecom Skeletal Analysis System and a 0- to 10-cm line pain scale, respectively. Repeated measures analysis of variance and Pearson correlation coefficients were calculated on or between back pain and nine posture variables and revealed significant increases in third trimester back pain and postures compared with first trimester back pain (p < .05) and postures for lumbar angle (p < .01), posterior head position (p < .01), right pelvic sagittal tilt (p < .01), and left pelvic sagittal tilt (p < .01). No significant relationships were found between magnitude of or change in posture and back pain. These results suggest that in the standing position the lumbar lordosis and sagittal pelvic tilt increased and head position become more posterior as women progressed from the first trimester to the last trimester of pregnancy. These postural changes, however, were not related to back pain. This suggests that many of the posture-correcting clinical exercise regimens given to pregnant women need to be investigated.

Adult↗

PubMed2002

Evaluation of postural tremor of finger for neuromuscular diseases and its application to the classification.

The purpose of this study is to verify the features of the power spectrum of postural tremors for neuromuscular disease patients and to classify the postural tremors. The subjects were 88 neuromuscular disease patients (30 Parkinson disease (PD), 25 cerebellar disease (CER), 7 multiple sclerosis (MS), 7 neuropathy (NEU), 10 motor neuron disease (MND), 9 myopathy (MYO)). The control subjects were 12 normal young persons and 10 normal aged persons. Postural tremor was detected by accelerator sensor. Postural tremor was recorded under the two postural conditions: The subjects maintained the index finger without or with a weight load of 50 g in a horizontal position while looking at a visual target in front of the tip of the index finger. The power spectrum was calculated by an auto-regressive model (AR model). The peak frequency and the peak power were evaluated under the two conditions. Two frequency components of 8-12 Hz and 20-25 Hz appeared in the postural tremor of both normal subjects and neuromuscular disease patients. The difference of the postural tremor between the subjects mainly appeared in the 8-12 Hz component during the postural tremor with a weight load. MYO patients belonged to one group (called as group P1) due to lower peak power, CER patients belonged to one group (called as group P2) due to higher peak power, and PD and MS patients belonged to one group (called as group P3) due to lower peak frequency and higher peak power. NER and MND patients belonged to one group (called as group N which meant normal group). These results suggested that the peak frequency and the peak power of the 8-12 Hz component were changed by the conditions of both spinal reflex system and central nervous system. An oscillator within the central nervous system produced the underlying frequency of 8-12 Hz component, while the amplitude of 8-12 Hz component was governed by both spinal reflex system and central nervous system. In conclusion, the classification of postural tremor for neuromuscular disease patients was a useful index to elucidate the mechanism of tremor oscillation and to assist in clinical diagnosis of neuromuscular disease.

Adult↗

PubMed2003

EMG characteristics of low back and lower limb muscles during forward bending posture.

The study observed forward bending posture and evaluated its effect on muscular activity. The Muscular activity was monitored through the Electromyography (EMG). The objective was to extend the evaluation method of EMG due to muscular load in maintaining the posture and to investigate the existence of muscular coordination between low back and lower limb muscles during the posture. Twelve male subjects were asked to maintain the postures of six stages in bending angles from 0 to 180 degrees. The EMG of erector spinae (ES) at L1 and L5 levels, hamstrings, and gastrocnemius were recorded and analyzed by power spectral density. The characteristics of muscular activities were observed through the EMG power spectrum and the frequency. The activity changes were normalized by the relative presentation and the standardization. The relative presentation showed the level of activity changes in each posture by taking the activity during upright standing as a reference posture, and the standardization was applied to overcome the dependence of the power spectrum and the frequency upon the high standard deviation. A t test with the paired data was also applied to compare the values of EMG of the respective stages of the posture. The results showed that the activity of ES significantly increased during bending posture with an angle up to 45 degrees, and reached silent activity at 90 degrees of flexion. On the other hand, the activity of the hamstrings and gastrocnemius were recognized even when ES activity started and reached the silent activity. The lower limb muscles were considered to be always active during all stages of the posture, and they provided a greater contribution when the ES was in the silent activity.

Adult↗

PubMed2006

Postural disorders and spatial neglect in stroke patients: a strong association.

PURPOSE: In this paper we analyse the arguments for a strong association between spatial neglect and postural disorders and attempt to better understand the mechanisms which underlie that. METHODS: We first provide a general overview of the available tools for a rational assessment of postural control in a clinical context. We then analyse the arguments in favour of a close relationship, although not necessarily causal, between spatial neglect and: 1) body orientation with respect to gravity (including verticality perception i.e. the visual vertical, the haptic vertical, and the postural vertical); 2) body stabilisation with respect to the base of support; 3) posturographic features of stroke patients; 4) and finally their postural disability in daily life. This second part of the paper is based both on the literature review and on results of our current research. RESULTS: Neglect patients show a dramatic postural disability, due both to problems in body orientation with respect to gravity and to problems in body stabilisation. It might be that these problems are partly caused by a neglect phenomenon bearing on graviceptive (somaesthetic > vestibular) and visual information serving postural control. This could correspond to a kind of postural neglect involving both the bodily and nonbodily domains of spatial neglect. The existence of distorsion(s) in the body scheme are also probably involved, especially to explain the weight-bearing asymmetry in standing, and probably an impaired multisegmental postural coordination leading to an impaired body stabilisation. CONCLUSION: The present paper explains why neglect patients show longer/worse recovery of postural-walking autonomy than other stroke patients.

Animals↗

PubMed1991

Postural differences between asymptomatic men and women and craniofacial pain patients.

A forward head position and rounded shoulders have been implicated in the development or perpetuation of craniomandibular disorders. Since women seek treatment for these problems more frequently than men, postural differences may account for the increased incidence of symptoms in women. The purposes of this study were (1) to compare the sagittal head and shoulder posture of asymptomatic men and women and (2) to compare the posture of asymptomatic and symptomatic women to determine differences in sagittal plane posture. Subjects were 20 asymptomatic men and women volunteers and nine consecutive women patients presenting for evaluation and treatment of craniomandibular pain. The subjects were compared using a valid, reliable, computer-assisted slide digitizing system called the Postural Analysis Digitizing System (PADS). Asymptomatic men and women did not differ in the postural characteristics associated with craniomandibular disorders. Sagittal posture does not appear to be a gender-related factor in these disorders. Symptomatic women, however, do display these postural characteristics to a greater extent than asymptomatic women. Evaluation and treatment of postural dysfunction should be included in the management of these patients.

Adult↗

PubMed1990

Cholinoceptive pontine reticular structures modify the postural adjustments during the limb movements induced by cortical stimulation.

1. Activation of the pontine reticular formation (pRF) and the related medullary inhibitory reticulospinal (RS) system decreases the postural activity. This effect can be achieved either by local injection into the dorsal pontine tegmentum of cholinergic agonists which excite cholinoceptive pRF neurons, or by injection of noradrenergic agents which block the inhibitory influence exerted by the locus coeruleus (LC) neurons on the pRF. The main aim on the present study was to analyze the effects of tonic activation of these pRF neurons on the postural adjustments accompanying limb movements induced by motor cortex stimulation. In particular, electrodes were implanted chronically in the motor cortex of cats and stainless steel guide tubes of small size, later used for drug injection, were set bilaterally into sites just above the responsive regions. 2. Limb flexion elicited by stimulation of the motor cortex was accompanied by a diagonal pattern of postural adjustment, characterized by a decreased force exerted by the limb diagonally opposite to the moving one and an increased force exerted by the other two. 3. Microinjection into the pRF of both sides of 0.25 microliter of the muscarinic agonist bethanechol at the concentration of 8 or 16 micrograms/microliters in buffered artificial cerebrospinal fluid produced a short-lasting episode of postural atonia followed by a period of reduced postural activity, during which the cats were still able to stand on the measurement platform. Under this condition no changes in threshold, latency and amplitude of the flexion response were observed in the performing limb; however, the postural responses were considerably affected. In particular, when the performing limb was a forelimb, the other anterior limb showed a dissociation of the postural response in two distinct components. The first anticipatory component, which had a short latency (12-15 msec) and was considered to be centrally triggered, decreased in amplitude after injection of bethanechol and sometimes disappeared; on the other hand the second component, which had a long latency (50-60 msec) and was thus considered to be of reflex origin, increased in amplitude, due to the instability resulting from the depression of the early postural response. Similar results also affected to a lesser extent the hindlimbs. Moreover, body oscillations were observed and monitored from the force platforms following the late component of the postural responses.(ABSTRACT TRUNCATED AT 400 WORDS)

Bethanechol↗

PubMed1989

[The supplementary motor area is implicated in the coordination between posture and movement in man].

The aim of the present experimental series was to investigate the central organization of the coordination between posture and movement in a bimanual load lifting task. The seated subject was instructed to maintain horizontal one forearm (postural arm) which was loaded with a 1 kg weight. The unloading was performed either by the experimenter (imposed unloading) or by a voluntary movement of the other arm (bimanual unloading). With the bimanual unloading, the movement control was accompanied by an anticipatory adjustment of the postural forearm flexors activity, which resulted in the maintenance of the forearm position despite the unloading. No change in the anticipatory postural adjustment was observed in one patient with complete callosal section. It was reduced in 5 patients with lesion of the SMA region, but only when the postural forearm was contralateral to the lesion. It is suggested that the SMA region contralateral to the postural forearm may select the circuits responsible for the phasic postural adjustments which are necessary to ensure postural maintenance, whereas the motor cortex contralateral to the voluntary movement controls both the movement and, via collaterals, the preselected circuits responsible for the associated postural adjustment.

Adult↗

PubMed1987

Postural adjustments associated with rapid voluntary arm movements in patients with Parkinson's disease.

To determine the extent to which deficits in coordination between posture and movement are influenced by postural disorders, postural adjustments associated with rapid voluntary arm movement were studied in PD patients and controls. EMG activity in postural muscles of the lower limbs and the trunk and local anteroposterior accelerations of the upper part of the leg were recorded in subjects who rapidly raised their arms to a horizontal position in response to a visual signal. The arm movement was characterized electromyographically by EMG activity from the deltoid muscle (anterior portion) and kinetically by acceleration of the arm. Study of characteristics of voluntary movement showed a nonsignificant increase in RT (simple-reaction time task) and an important increase in MT. There were important differences between PD patients and control subjects with regard to postural adjustments. Timing between voluntary movement and postural movement was anticipatory in 5% of PD patients, whereas it was anticipatory in 100% of control subjects. In PD patients, organization of early postural adjustments was not specific to voluntary movement; in control subjects, organization of early postural adjustments was specific to the forthcoming movement. Last, a possible functional relation between the "quality" of postural adjustments and a reduction in motor performance of normal subjects is suggested.

Adult↗

PubMed1997

[Preferential posture in infants; serious demands on health care].

OBJECTIVE: To determine the prevalence of preferential posture in infants up to the age of six months; to determine the percentage of referrals for diagnostics and (or) treatment; to gather information about risk factors. SETTING: Infant Health Care (IHC) centres in the Netherlands. DESIGN: Descriptive controlled investigation. METHOD: During September 1995 a total of 7609 infants were examined by 167 IHC doctors for the presence of preferential posture. Data on the physical examination and on the occurrence of risk factors were registered for every child with preferential posture (n = 623) and for a next child of the same age and the same sex without preferential posture. Six months later 468 children with preferential posture were re-examined. RESULTS: The prevalence of preferential posture was 8.2% and was highest in children below 16 weeks of age. The ratio boy:girl was 3:2. Firstborns, premature children and children in breech position at the time of delivery, had a higher risk for preferential posture. The position of the child after the first week of life and the way of feeding proved to be significant risk factors. After six months 32% of the children with preferential posture had been referred for additional diagnostics and, if necessary, treatment. CONCLUSION: Preferential posture is frequently observed and leads to referral, additional diagnostics and (or) treatment in 2.5% of all children up to 6 months of age.

Birth Order↗

PubMed1997

[Changes in posture in whiplash evaluated by static posturography].

Analyzing vestibular-spinal reflex by recording changes in the pressure center over time, static posturography provides precise, repeatable information regarding a person's posture and subsequent postural strategy. Moreover, using the detected postural pattern, this can presage likely genesis of problems in equilibrium. The purpose of the present work was to evaluate posturographic findings in subjects with chronic or persistent whiplash (WL)-induced disequilibrium in order to determine any clear postural pattern able to indicate the likely genesis of the disorder. Fifty young subjects were selected for the study: 28 (6 females) affected with equilibrium problems resulting from WL-type cervical strain and 22 (5 females) normal, age compatible controls (C) (mean age of the groups: WL = 37 +/- 14.3; C = 32.4 +/- 6.7; p = n.s.). The results obtained were statistically processed with a personal computer and specific software (Windows-SPSS). In the analysis of the means (T-test and ANOVA analysis of variance) p < 0.05 was considered significant. In the WL group there was an increase in the antero-posterior axis oscillation frequency as compared to the control group. This is indicated by the FFTY parameter in tests performed both with eyes open and closed. Likewise, in both tests, there was a decrease in the LFS value, a parameter correlating length with surface. The surface was increased in the WL group as compared to group C although this increase was significant only when the test was performed with eyes closed. In addition, the average velocity and standard deviation of velocity increased in the WL group but this was only statistically significant when the eyes were open. The results obtained in the present study show that whiplash victims show an increase in antero-posterior oscillation frequency at the pressure center, as found in the open and closed-eye tests. This suggests that in WL subjects there is an evident disturbance of the fine postural system, leading to an increase in the surface parameters, tracing length and a decrease in LFS function. The onset of this partial postural decompensation can be seen in: a) decrease in fine static postural control which is reflected in an increase in body surface oscillation; b) an increase in energy consumption to maintain orthostatism as revealed in the decreased LFS. In conclusion, it appears reasonable to assume that cervical proprioceptive alterations play a preeminent role in the genesis of whiplash-induced chronic postural instability. This would result in an attempt to vary the physiology from an ankle to a hip strategy; incomplete manifestation of this new posture would cause the feeling of instability mentioned by the patients and documented by posturography.

Adult↗

PubMed2000

Surgery for full-thickness macular holes with short-duration prone posturing: results of a pilot study.

PURPOSE: To see whether surgical success and complication rates in surgery for full-thickness macular holes (FTMH) followed by 5 days prone posturing are comparable to those obtained with longer posturing regimes recorded in the literature. METHODS: A pilot study was carried out of pars plana vitrectomy, autologous platelet adjunct and 16% C2F6 tamponade followed by 5 days prone posturing in 38 eyes of 34 patients with idiopathic FTMH. A follow-up postal questionnaire was used to assess patients' perception of posturing and outcome. RESULTS: Fifty-three per cent of eyes gained 2 or more lines of Snellen acuity. Twenty-four per cent of patients with symptom duration of 12 months or less (29 patients) achieved a visual acuity of 6/12. Fifty-eight per cent of patients achieved N8 or better near vision. The only significant predictor of post-operative Snellen acuity was the stage of the hole (p = 0.02). Eighty-six per cent of questionnaire respondents felt that surgery had improved their quality of life. Eighty-seven per cent of all patients reported a reduction in, or elimination of, metamorphopsia. Fifty-four per cent of patients described posturing for 5 days as difficult or very difficult. Five patients admitted to posturing for less than 12 h a day, but all stated that they had postured for the full 5 days. Cataract was the commonest complication observed in this series (42% of patients have had or been listed for cataract surgery). CONCLUSIONS: Five days of prone posturing following vitrectomy for FTMH with autologous plaletet concentrate and C2F6 tamponade afforded success and complication rates comparable to those in published studies with longer posturing times.

Aged↗

PubMed2005

Experience of handicap and anxiety in phobic postural vertigo.

CONCLUSIONS: We found a difference in gender distribution in a population of phobic postural vertigo patients compared with dizzy patients seen in general neuro-otological practice. It appears as if women with phobic postural vertigo suffer more and are more handicapped by dizziness than both men with phobic postural vertigo and a population with dizziness. These differences may reflect other causes of phobic postural vertigo besides anxiety, such as gender-related coping behaviour and postural strategy. OBJECTIVE: Anxiety influences the degree of suffering and handicap in dizzy patients. Experiences of anxiety and handicap were investigated among a population with phobic postural vertigo. MATERIAL AND METHODS: Using the Dizziness Handicap Inventory, the Vertigo Symptom Scale and the Vertigo Handicap Questionnaire, 34 consecutive patients with phobic postural vertigo were compared with a population of 95 consecutive patients seen at a balance disorder clinic. RESULTS: Patients with phobic postural vertigo scored higher than the control subjects with respect to all parameters with the exception of the physical subscale of the Dizziness Handicap Inventory. Because there were significantly more women in the control group we performed a gender-specific analysis of the results. The higher test scores among patients with phobic postural vertigo can be explained by the higher scores among women in this group, while the test results for men were more similar to those of the control group.

Adult↗

PubMed1992

Effects of varying load conditions on the organization of postural adjustments during voluntary arm flexion.

One purpose of the experiments reported here was to further clarify the effect of varying loads on postural adjustments. Another was to reevaluate whether or not the timing of electromyographic (EMG) activity in the postural muscle is preprogrammed. To accomplish these goals, we compared the effect of the presence or absence of prior knowledge of a load on the timing of EMG activity in the postural muscle (biceps femoris [BF]) with that in the focal muscle (anterior deltoid [AD]). Although the sequence of EMG activation was similar under conditions with and without a load, the timing of postural EMG activities (BFi, ipsilateral BF; BFc, contralateral BF) in associated postural adjustments was dependent on the force of arm movement, and the latencies of postural EMG activities (BFi-BFc) were dependent on the speed of arm movement. This indicates that EMG changes in the upper (focal muscle) and lower limbs (postural muscle) were triggered by different motor programs. Moreover, similar EMG activities were observed in postural muscles when the subject had advance knowledge of the presence or the absence of a load. Thus, this suggests that BFi may be centrally preprogrammed (anticipatory regulation) and BFc may be feedback regulated. Furthermore, environmental information may be a critical source of influence on those postural responses.

Journal Article↗

PubMed1996

Physical Workload Analysis Among Small Industry Activities Using Postural Data.

Small industry workers are often involved in manual handling operations that require awkward body postures, therefore, musculoskeletal disorders and occupational injuries are a major problem. In this study, various types of tasks were recorded with a video camera to chart and analyze different postures by computerized OWAS (Ovako Working Posture Analysing System). Collected data showed that poor postures were adopted not only for lifting or hammering operation but also for other tasks; mostly with bent and twisted back. The main aim was to determine the physical workload by identifying harmful postures and to develop recommendations for improving the existing situation. Forty-eight male workers from eight different units (M age = 37 years) participated. The performed activities were then divided into 26 subtasks. Altogether, 1,534 postures were selected for analysis and then classified into different OAC (OWAS Action Categories). From all observations, unhealthy postures, for which corrective measures had to be considered immediately (i.e., 10.6% classified as OAC III, and 3.3% as OAC IV), were found. The applied method was useful in determining the physical workload by locating potential activities due to harmful postures, providing a detailed description with analysis, and suggesting successful means to reduce postural load.

OWAS↗

PubMed1981

Relation of automatic postural responses and reaction-time voluntary movements of human leg muscles.

This study contrasts the properties of compensatory postural adjustments in response to movements of the support surface with those of reaction-time voluntary movements in human subjects. Subjects stood upon a six degrees-of-freedom movable platform and performed tone and movement-triggered voluntary sways about the ankle joints both under conditions of postural stability and instability. These triggered movements could be executed as rapidly as postural adjustments to support surface perturbations (80-120 ms), but only when the former were well practiced, single-choice (direction) and were performed under conditions of postural stability. Evaluation of the properties of postural adjustments and reaction-time voluntary movements revealed a number of clear organizational differences between the two categories of movement, but most interesting was the finding that, when reaction-time movements were triggered by or at the onset of platform movement, the postural adjustments always occurred first. Only when subjects were given a tone trigger 50 ms in advance of platform movement were they able to execute the reaction-time movement first. We found that the dichotomous voluntary/reflexive classification of movements was not consistent with all of the identified properties of postural adjustments and reaction-time movements. Instead, we find a system which classifies movements by function, as either stabilizating or orientational adjustments, to be more useful. In the context of whole-body movement then, intentional focal components would be closely associated with others directed towards postural stabilization.

Electromyography↗