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The relationships between paw preference and the right- and left-brain weights in male and female adult cats: ipsilateral and contralateral motor control with regard to asymmetric postural and manipulative actions.

Paw preference (food reaching) with regard to relative right-and left-brain weights was studied in adult cats. In the right-pawed (RH) male and female cats, the right-paw use increased and the left-paw use decreased with increasing asymmetry coefficient (AC) for the right- and left brain-weight. The right-paw use increased with increasing the right-brain weight in RH males, and decreased with increasing the left-brain weight in RH females. There was no significant correlation between paw use and AC in left-pawed (LH) males; the right-paw use decreased and the left paw use increased with increasing AC in LH females. The right-paw use decreased with increasing left brain weight (no correlation with right brain) in LH males. In LH females, the right-paw use decreased with the right-brain weight, and increased with the left-brain weight. The left-paw use increased with the left-brain weight in LH males (no correlation with the right-brain weight). The left-paw use increased with the right-brain weight and decreased with the left-brain weight in LH females. These results were explained by supraspinal and spinal reciprocal interactions between the postural and manipulative systems with regard to contralaterality and ipsilaterality of motor control in cerebral and manual lateralization.

Animals↗
PubMed1978

Postural sway in amputees and normal subjects.

The postural sway of amputees was investigated quantitatively in fifty patients with above-the-knee amputations and in twenty-nine patients with below-the-knee amputations. The factors evaluated were: (1) the mean speed of sway: (2) the range of movement in the sagittal and coronal planes; and (3) the dependence on vision as indicated by the ratio of eyes-open to eyes-closed values. The results demonstrated that in amputees there is an increased dependence on vision for maintenance of the erect posture. Postural sway in patients with below-the-knee amputations was found to be significantly greater than that in those with above-the-knee amputations. Postural sway increased with age; but the visual dependence for the control of postural sway was independent of age.

Age Factors↗
PubMed2006

Dynamical structure of center-of-pressure trajectories in patients recovering from stroke.

In a recent study, De Haart et al. (Arch Phys Med Rehabil 85:886-895, 2004) investigated the recovery of balance in stroke patients using traditional analyses of center-of-pressure (COP) trajectories to assess the effects of health status, rehabilitation, and task conditions like standing with eyes open or closed and standing while performing a cognitive dual task. To unravel the underlying control processes, we reanalyzed these data in terms of stochastic dynamics using more advanced analyses. Dimensionality, local stability, regularity, and scaling behavior of COP trajectories were determined and compared with shuffled and phase-randomized surrogate data. The presence of long-range correlations discarded the possibility that the COP trajectories were purely random. Compared to the healthy controls, the COP trajectories of the stroke patients were characterized by increased dimensionality and instability, but greater regularity in the frontal plane. These findings were taken to imply that the stroke patients actively (i.e., cognitively) coped with the stroke-induced impairment of posture, as reflected in the increased regularity and decreased local stability, by recruiting additional control processes (i.e., more degrees of freedom) and/or by tightening the present control structure while releasing non-essential degrees of freedom from postural control. In the course of rehabilitation, dimensionality stayed fairly constant, whereas local stability increased and regularity decreased. The progressively less regular COP trajectories were interpreted to indicate a reduction of cognitive involvement in postural control as recovery from stroke progressed. Consistent with this interpretation, the dual task condition resulted in less regular COP trajectories of greater dimensionality, reflecting a task-related decrease of active, cognitive contributions to postural control. In comparison with conventional posturography, our results show a clear surplus value of dynamical measures in studying postural control.

Aged↗
PubMed1984

Callosal syndrome: implications for understanding the neuropsychology of stroke.

A case is presented of callosal syndrome following cerebral hemorrhage and amphetamine abuse in a 26-year-old right-handed man. There were few hemispheric findings but a full callosal syndrome including left apraxia to verbal commands, left tactile anomia, left agraphia, right constructional apraxia, failure of blindfolded side-to-side hand replication and form-board testing showing loss of interhemispheric transmission including intermanual interference. The "draw-a-clock" test showed left inattention when drawn with the right hand but not the left, and perseveration was noted for spatial tasks done with the right hand and symbolic tasks done with the left. The patient recovered functionally almost completely but testing demonstrated continued loss of interhemispheric transmission. The case is considered of most interest for its potential in explaining phenomena observed in severe unilateral hemispheric lesions. Our findings suggest that perseveration is not a dysfunction of the damaged portion of the brain, but a phenomenon associated with intact brain attempting unfamiliar tasks. The persistence of left hemi-inattention is attributed to the inability of the left hemisphere to utilize spatial information to compensate for the phenomenon of inattention. Left-sided dyskinesia following left hemisphere lesions was attributed to the lack of symbolic information necessary to perform some movements. Dysprosody was attributed to lack of tonal information to the left hemisphere. Recovery of function following severe unilateral lesions may be largely due to compensatory learning by the intact hemisphere and assertion of ipsilateral control. As our patient originally assumed an inverted left-handed writing posture, we assume the posture is controlled by the right hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2001

Static postural sway, proprioception, and maximal voluntary quadriceps contraction in patients with knee osteoarthritis and normal control subjects.

OBJECTIVES: To investigate whether subjects with knee osteoarthritis (OA) have reduced static postural control, knee proprioceptive acuity, and maximal voluntary contraction (MVC) of the quadriceps compared with normal controls, and to determine possible independent predictors of static postural sway. METHODS: 77 subjects with symptomatic and radiographic knee OA (58 women, 19 men; mean age 63.4 years, range 36-82) and 63 controls with asymptomatic and clinically normal knees (45 women, 18 men; mean age 63 years, range 46-85) underwent assessment of static postural sway. 108 subjects (59 patients, 49 controls) also underwent assessment of knee proprioceptive activity and MVC (including calculation of quadriceps activation). In patients with knee OA knee pain, stiffness, and functional disability were assessed using the WOMAC Index. The height (m) and weight (kg) of all subjects was assessed. RESULTS: Compared with controls, patients with knee OA were heavier (mean difference 15.3 kg, p<0.001), had increased postural lateral sway (controls: median 2.3, interquartile (IQ) range 1.8-2.9; patients: median 4.7, IQ range 1.9-4.7, p<0.001), reduced proprioceptive acuity (controls: mean 7.9, 95% CI 6.9 to 8.9; patients: mean 12.0, 95% CI 10.5 to 13.6, p<0.001), weaker quadriceps strength (controls: mean 22.5, 95% CI 19.9 to 24.6; patients: mean 14.7, 95% CI 12.5 to 16.9, p<0.001), and less percentage activation of quadriceps (controls: mean 87.4, 95% CI 80.7 to 94.2; patients: mean 66.0, 95% CI 58.8 to 73.2, p<0.001). The significant predictors of postural sway were knee pain and the ratio of MVC/body weight. CONCLUSIONS: Compared with age and sex matched controls, subjects with symptomatic knee OA have quadriceps weakness, reduced knee proprioception, and increased postural sway. Pain and muscle strength may particularly influence postural sway. The interaction between physiological, structural, and functional abnormalities in knee OA deserves further study.

Adult↗
PubMed2006

Forward head posture and neck mobility in chronic tension-type headache: a blinded, controlled study.

Forward head posture (FHP) and neck mobility were objectively assessed in 25 patients with chronic tension-type headache (CTTH) and 25 healthy controls. Side-view pictures were taken in a sitting position to measure the cranio-vertebral angle. A cervical goniometer was employed to measure the range of all cervical motions. Patients with CTTH showed a smaller cranio-vertebral angle (45.3 degrees +/- 7.6 degrees) than controls (54.1 degrees +/- 6.3 degrees), thus presenting a greater FHP (P < 0.001). Patients also had lesser neck mobility for all cervical movements, except for right lateral flexion (P < 0.01). There was a positive correlation between the cranio-vertebral angle and neck mobility. Within the CTTH group, a negative correlation was found between the cranio-vertebral angle and headache frequency, but neck mobility did not correlate with headache parameters. Further research is needed to define a potential role of FHP and restricted neck mobility in the origin or maintenance of TTH.

Adult↗
PubMed1982

Effect of chest physiotherapy on the removal of mucus in patients with cystic fibrosis.

We studied the effectiveness of some of the components of a physiotherapy regimen on the removal of mucus from the lungs of 6 subjects with cystic fibrosis. On 5 randomized study days, after inhalation of a 99mTc-human serum albumin aerosol to label primarily the large airways, the removal of lung radioactivity was measured during 40 min of (a) spontaneous cough while at rest (control), (b) postural drainage, (c) postural drainage plus mechanical percussion, (d) combined maneuvers (postural drainage, deep breathing with vibrations, and percussion) administered by a physiotherapist, (e) directed vigorous cough. Measurements continued for an additional 2 h of quiet rest. Compared with the control day, all forms of intervention significantly improved the removal of mucus: cough (p less than 0.005), physiotherapy maneuvers (0.005 less than or equal to p less than 0.01), postural drainage (p less than 0.05), and postural drainage plus percussion (p less than 0.01). However, there was no significant difference between regimented cough alone and therapist-administered combined maneuvers, nor between postural drainage alone and with mechanical percussion. We conclude that in cystic fibrosis, vigorous, regimented cough sessions may be as effective as therapist-administered physiotherapy in removing pulmonary secretions. Postural drainage, although better than the control maneuver, was not as effective as cough and was not enhanced by mechanical percussion. Frequent, vigorous self-directed cough sessions are potentially as useful as more complex measures for effective bronchial toilet.

Adolescent↗
PubMed2003

Development of virtual reality stimuli for force platform posturography.

People relying much on vision in the control of posture are known to have an elevated risk of falling. Dependence on visual control is an important parameter in the diagnosis of balance disorders. We have previously shown that virtual reality (VR) methods can be used to produce visual stimuli that affect balance, but suitable stimuli need to be found. In this study, the effect of six different VR stimuli on the balance of 22 healthy test subjects was evaluated using force platform posturography. We report in more detail and expand the results published earlier. According to the tests two of the stimuli have a significant destabilizing effect on balance. In addition a significant displacement effect on the subject's center of pressure (COP) was found. Thus it is shown that the design of VR stimuli to cause different effects on the control of balance is possible.

Adult↗
PubMed1990

Some visual influences on human postural equilibrium: binocular versus monocular fixation.

The importance of vision for postural equilibrium has long been known; traditionally, this visual contribution to the control of posture has been analyzed primarily in terms of optical and retinal phenomena. Recently, however, there has been some suggestion that binocular and monocular fixation of identical stimuli have differential effects. Three experiments were conducted in order to measure self-generated movement (sway during quiet standing) of the body's center of gravity while field structure, ankle proprioception, and binocular/monocular fixation were varied. Field structure was varied from total darkness, to the presence of single and multiple LEDs in the dark, to full field structure (i.e., the richness of the feed back information was varied). Ankle proprioception was varied by changing foot position from side-by-side to heel-to-toe positions. Results indicate that (1) ankle-joint input is a significant factor in reducing sway, (2) binocular fixation attenuates sway relative to monocular fixation, under otherwise identical visual conditions, and (3) this difference persists in total darkness. Taken together, the data indicate that the visual influence on postural equilibrium results from a complex synergy that receives multimodal inputs. A simple optical/retinal explanation is not sufficient.

Adolescent↗
PubMed1986

A clinical perspective on aging.

Immobility, falls, incontinence, mental confusion and homeostatic disturbances are the major problems encountered in elderly patients. These occur with increasing frequency in the very old (age greater than 85) but studies have shown that the level of disability for those aged 65-84 remains no more than 15-20%. As at all ages, a small proportion of elderly experience most of the clinical problems. To improve our performance in managing these requires education of medical trainees, cooperation between acute and long-term care institutions and a concentrated program of biomedical research. Therapy designed to light up fading receptors or increase neurotransmitter function to maintain cerebral control mechanisms for posture, excretion and appetite control will achieve more than psychosocial or administrative attempts to solve such clinical problems.

Aged↗
PubMed1983

Lumbar facet syndrome: spinographic assessment of treatment by spinal manipulative therapy.

Spinographic parameters of a group of patients with extension facet subluxations and a group with herniated disc nucleus pulposus of the lumbar spine were evaluated pre- and post-manipulative treatment. A statistically significant decrease in the mean disc angle at the involved level in the extension facet subluxation group was seen with the mean post-treatment disc angle more closely resembling that of the controls. Likewise, a statistically significant increase occurred in the mean disc angle at the involved level in the disc herniation group post-treatment to one more closely resembling that of the controls. Distinct postural configurations were identified in the two test groups. That of the disc group normalized post-treatment, suggesting it to be a secondary pathomechanical process such as antalgia. The postural complex of the facet group was significantly different than that of the control group, but did not change significantly after correction of the acute lesion by manipulation, suggesting it to possibly be an antecedent etiological factor to these lesions.

Chiropractic↗
PubMed2004

Beat-to-beat heart rate and QT variability in patients with congestive cardiac failure: blunted response to orthostatic challenge.

BACKGROUND: Congestive cardiac failure is associated with increased sympathetic activity and impaired baroreflex function. We sought to test the hypothesis that these patients also have blunted response of beat-to-beat QT interval variability during orthostatic challenge. METHODS: We compared beat-to-beat heart rate and QT interval data in 17 patients with congestive cardiac failure and 17 age-matched normal controls in supine normal breathing, supine controlled breathing, and standing controlled breathing conditions. The ECG data were acquired in lead II configuration at a sampling rate of 1000 Hz. RESULTS: Supine controlled breathing was associated with an increase in spectral HF power (0.15-0.5 Hz) of HR and QT interval time series compared to spontaneous breathing condition only in controls. While there were significant changes in HR, HR LF power, HR LF/HF ratios, and QT variability measures in standing posture in controls, there were no such changes in patients. CONCLUSIONS: This impairment of postural changes of HR variability is most likely due to an impaired baroreceptor function in patients with congestive heart failure. The etiology of this is likely due to an increased cardiac sympathetic and a decreased vagal function. However, the relationship of postural changes in beat-to-beat QT interval variability and baroreflex need further investigation.

Analysis of Variance↗
PubMed1990

Assessment of balance control in humans.

Balance and posture of the body is essential to most human locomotion. Because humans are bipeds with about 2/3 of their mass located 2/3 of body height from the ground the control system is critical. In the elderly balance control degenerates. Falls represent a major health problem and the fear of falls is the major deterrent to daily mobility. Many measures have evolved to assess balance, varying from crude balance tasks to sophisticated perturbations. This paper summarizes the balance control task as it relates to standing and walking and details current assessment techniques and equipment. Additional information is provided by the authors to demonstrate from an electromyographical and biomechanical perspective the mechanisms and characteristics of the postural control system in both standing and walking.

Biomechanical Phenomena↗
PubMed2002

Virtual reality stimuli for force platform posturography.

People relying much on vision in the control of posture are known to have an elevated risk of falling. Dependence on visual control is an important parameter in the diagnosis of balance disorders. We have previously shown that virtual reality methods can be used to produce visual stimuli that affect balance, but suitable stimuli need to be found. In this study the effect of six different virtual reality stimuli on the balance of 22 healthy test subjects was evaluated using force platform posturography. According to the tests two of the stimuli have a significant effect on balance.

Adult↗
PubMed1982

Is handwriting posture associated with differences in motor control? An analysis of asymmetries in the readiness potential.

Levy and Reid's [1] hypothesis that persons who write using the inverted posture have ipsilateral control of distal limb movements, particularly those involved in handwriting, was tested in three experiments in which asymmetries in the readiness potential (RP) were measured. In the first experiment, each subject executed a self-paced repetitive squeeze. Contralaterally larger RPs were recorded from all subjects, irrespective to handwriting posture. In two other experiments, subjects performed the self-paced squeeze in one condition and wrote a single word repetitively in an analogous condition. Larger RPs were recorded over the contralateral cerebral hemisphere in most inverted-writing subjects in both conditions. Ipsilaterally larger RPs were recorded, however, from some left-handers while writing. These findings suggest that, although control of certain movements may originate from the ipsilateral motor cortex in a small proportion of left-handers, handwriting posture does not index this difference.

Adolescent↗
PubMed1999

Does the coordination between posture and movement during human whole-body reaching ensure center of mass stabilization?

The whole-body center of mass (CoM) has been classically regarded as the stabilized reference value for human voluntary movements executed upon a fixed base of support. Axial synergies (opposing displacements of head and trunk with hip segments) are believed to minimize antero-posterior (A/P) CoM displacements during forward trunk movements. It is also widely accepted that anticipatory postural adjustments (APAs) create forces of inertia that counteract disturbances arising from the moving segment(s). In the present study, we investigated CoM stabilization by axial synergies and APAs during a whole-body reaching task. Subjects reached towards an object placed on the ground in front of them in their sagittal plane using a strategy of coordinated trunk, knee, and hip flexion. The reaching task imposed constraints on arm-trajectory formation and equilibrium maintenance. To manipulate equilibrium constraints, differing conditions of distance and speed were imposed. The comparison of distance conditions suggested that axial synergies were not entirely devoted to CoM stabilization: backward A/P hip displacements reduced as head and trunk forward A/P displacements increased. Analysis of upper- and lower-body centers of mass in relation to the CoM also showed no strict minimization of A/P CoM displacements. Mechanical analysis of the effects of APAs revealed that, rather than acting to stabilize the CoM, APAs created necessary conditions for forward CoM displacement within the base of support in each condition. The results have implications for the CoM as the primary stabilized reference for posture and movement coordination during whole-body reaching and for the central control of posture and voluntary movement.

Adolescent↗
PubMed1979

[Role of secondary hyperaldosteronism in the pathomecanism of hydropic decompensation in the cirrhotic patient (author's transl)].

Plasma aldosterone levels before and after walking were compared in a series of 10 controls and 41 patients with cirrhosis of the liver. The latter were distributed in the following way: 8 had compensated cirrhosis, the remaining 33 were in a situación of hydropic decompensation, 10 with associated renal insufficiency, and 23 without. Basal aldosterone levels in compensated cirrhotics were similar to those of the controls, but these values increased significantly more than the controls following postural stimulation. Decompensated cirrhotics without renal insufficiency had significantly higher values than the controls, both in basal conditions and after stimulation. The highest values corresponded to the decompensated cirrhotic patients with renal insufficiency who were in advanced stages of liver disease. On the basis of the present findings and those of other authors, it is suggested that a certain reduction in the metabolic clearance of aldosterone appears to exist in hepatic cirrhosis. However, hormonal hyperproduction is the dominant factor in the pathogenic mechanism of secondary hyperaldosteronism. The pathogenesis of the excessive production of hormone is discussed. In conclusion, it appears that the scant affluence of sodium to the macula densa may be the primary factor in explaining this common situation in patients with cirrhosis of the liver.

Adult↗