Effect of body tilt on apparent verticality, apparent body position, and their relation.

1964 ◽  
Vol 67 (2) ◽  
pp. 142-147 ◽  
Author(s):  
Martin Bauermeister
Keyword(s):  
Circulation ◽  
2020 ◽  
Vol 142 (Suppl_4) ◽  
Author(s):  
Yaël Levy ◽  
Rocio Fernandez ◽  
Fanny Lidouren ◽  
Matthias Kohlhauer ◽  
Lionel Lamhaut ◽  
...  

Introduction: Extracorporeal cardiopulmonary resuscitation (E-CPR) using extracorporeal membrane oxygenation (ECMO) is widely proposed for the treatment of refractory cardiac arrest. Hypothesis: Since cerebral autoregulation is altered in such conditions, body position may modify hemodynamics during ECPR. Our goal was to determine whether a whole body tilt-up challenge (TUC) could lower intracranial pressure (ICP) as previously shown with conventional CPR, without deteriorating cerebral blood flow (CBF). Methods: Pigs were anesthetized and instrumented for the continuous evaluation of CBF, ICP and systemic hemodynamics. After 15 min of untreated ventricular fibrillation they were treated with 30 min of E-CPR followed by sequential defibrillation shocks until resumption of spontaneous circulation (ROSC). ECMO was continued after ROSC to target a mean arterial pressure (MAP) >60 mmHg. Animals were maintained in the flat position (FP) throughout protocol, except during a 2 min TUC of the whole body (+30°) at baseline, during E-CPR and after-ROSC. Results: Four animals received the entire procedure and ROSC was obtained in 3/4. After cardiac arrest, E-CPR was delivered at 29±2 ml/kg/min to maintain a MAP of 57±8 mmHg in the FP. CBF was 28% of baseline and ICP remain stable (12±1 vs 13±1 mmHg during ECPR vs baseline, respectively). Under baseline pre-arrest conditions TUC resulted in a significant decrease in ICP (-63±7%) and CBF (-21±3%) versus the FP, with no significant effect on systemic hemodynamics. During E-CPR and after ROSC, TUC markedly reduced ICP but CBF remained unchanged vs the FP (Figure). Conclusion: During E-CPR whole body TUC reduced ICP without lowering CBF compared with E-CPR flat. Additional investigations with prolonged TUC and selective head and thorax elevation during E-CPR are warranted.


2017 ◽  
Vol 158 (52) ◽  
pp. 2079-2085
Author(s):  
Máté Burkus ◽  
István Márkus ◽  
Bálint Niklai ◽  
Miklós Tunyogi-Csapó

Abstract: Introduction: Sagittal alignment of the pelvis is typically characterized using three fundamental parameters. Among these, pelvic incidence is traditionally considered to be anatomically ‘constant’. Aim: We aimed to analyze the pelvic parameters of low back pain patients with suspected sacroiliac joint laxity. Method: Pelvic parameters were assessed in standing and seated EOS 2D/3D radiographs of 48 cases of persistent low back pain, and compared to upper body position using cluster analysis and t-test. Results: Median pelvic incidence did not differ statistically between standing and sitting (47.8°–47.7°). However, in individual analysis 7 cases (15%) exhibited a forward tilt in their upper body with an increased pelvic incidence, and 7 cases (15%) showed a backward upper body tilt. No change was found in 34 cases. Conclusion: Our results indicate the pelvis should not be regarded as a rigid unit, as in some cases significant appreciable sacroiliac joint laxity can occur. Orv Hetil. 2017; 158(52): 2079–2085.


Author(s):  
A. Harvey Baker ◽  
Leonard Cirillo ◽  
Seymour Wapner
Keyword(s):  

1976 ◽  
Vol 42 (3) ◽  
pp. 747-750 ◽  
Author(s):  
Peter E. Comalli ◽  
Stephanie Schmidt ◽  
Morton W. Altshuler

20 profoundly deaf and 20 normal hearing children from ages 10 to 13 were compared as to their ability to locate visually the position of apparent vertical and the apparent location of the longitudinal axis of the body under erect and 30° left and right body-tilt. Both deaf and normal hearing children were able accurately to locate a rod to the apparent visual vertical, but deaf children were significantly more accurate in aligning a rod to their apparent body-position than hearing children. This finding is discussed from both a learning view and from a hypothesis of developmental lag.


1967 ◽  
Vol 24 (1) ◽  
pp. 43-50 ◽  
Author(s):  
M. Bauermeister ◽  
S. Wapner ◽  
H. Werner

Eighty Ss, 40 male and 40 female, indicated by means of a luminescent rod the location of their longitudinal body axis (apparent body position) under body tilt ranging from 90° left (counterclockwise), through upright, to 90° right (clockwise). The luminescent rod was presented by two psychophysical methods: (a) the method of limits and (b) the method of constant stimuli. Deviations of apparent from objective body position showed significant differences between the two methods. The results were interpreted in terms of an organismic theory of perception, utilizing the notion of a dynamic body schema as spatial reference system which was subject to modifications due to the method of stimulus presentation.


1981 ◽  
Vol 52 (2) ◽  
pp. 455-458
Author(s):  
Colin B. Pitblado ◽  
Charles S. Mirabile ◽  
John E. Richard

Judgments of the visual, vertical, made without a visual reference frame-work, from a tilted-body position, result in systematic constant errors (Aubert effects). Pitblado and Mirabile (1977) showed that these errors vary with motion-sickness susceptibility, persons of intermediate susceptibility showing the greatest error. Recent exploratory work suggested patterns of progressive intra-session change in Aubert effects which might further differentiate groups of differing susceptibility. The raw data from Pitblado and Mirabile's 1977 study were reanalyzed for possible progressive change. This new analysis showed significant progressive reductions in Aubert effects for groups originally high and low, but a nearly significant increase in the intermediate group. New implications concerning group differences in vestibular function are discussed.


1985 ◽  
Vol 54 (1) ◽  
pp. 123-133 ◽  
Author(s):  
I. Suzuki ◽  
S. J. Timerick ◽  
V. J. Wilson

In decerebrate cats, we have studied the response of neurons in the L3-L6 segments of the spinal cord to stimulation of neck and vestibular receptors. Neck receptors were stimulated by head rotation in labyrinthectomized cats or by body rotation with the head fixed in labyrinth-intact cats. Vestibular receptors were stimulated by whole-body tilt in the latter preparation. Most neurons were located outside the motoneuron nuclei and were arbitrarily classified as interneurons. Combinations of roll and pitch stimuli at frequencies of 0.1 or 0.05 Hz were used to determine the horizontal component of the polarization vector, i.e., the best direction of tilt, for each neuron. Two types of stimuli were used; rotation of a fixed angle of tilt around the head or body ("wobble," Ref. 22) or sinusoidal stimuli in several planes. Polarization vectors of the responses to neck stimulation were widely distributed; different neurons responded best to roll, pitch, and angles in between. For every neuron, the amplitude of the response decreased as the cosine of the angle between the direction of maximal sensitivity and the plane of the stimulus. The direction of the vector remained stable as the frequency of stimulation was varied. Neurons with different vectors had similar dynamics that resembled those of cervical interneurons (27). Many neurons responded to both neck and vestibular stimulation, although the vestibular response usually had a much lower gain. Neck and vestibular vectors were approximately opposite in direction. We suggest that neck responses originate in receptors, probably spindles, in perivertebral muscles. Each of these muscles presumably is best stretched by a particular direction of pull. It seems likely that convergence from receptors in selected muscles determines the direction of a spinal neuron's vector. Vestibular responses probably are due mainly to activity in otolith afferents.


1978 ◽  
Vol 47 (3_suppl) ◽  
pp. 1051-1056 ◽  
Author(s):  
Eric Sigman ◽  
Donald R. Goodenough ◽  
Michael Flannagan

The existence of an illusion of self-tilt in the rod-and-frame test was demonstrated using a magnitude-estimation procedure. Subjects, seated in a tiltable chair, estimated their body tilt after being placed in one of 13 body tilt positions and while viewing a rod-and-frame display. A shift of the apparent body position occurred in the opposite direction of frame tilt. The results are consistent with earlier findings using the method of body and head adjustment.


1976 ◽  
Vol 42 (3_suppl) ◽  
pp. 1195-1200 ◽  
Author(s):  
Colin Pitblado

15 women and 24 men were compared on a visual orienting task requiring observers to set a luminous line to a vertical position while viewing from a laterally tilted body position. No visible frame of reference was available. Women made no significant error as a group, while the men's average settings deviated approximately 7° from vertical, in the same direction as body tilt. This result reverses the direction of sex differences usually reported on orienting tasks and specifies a limitation on the usefulness of the “field dependence” concept as a predictor of comparative spatial performances of men and women.


2007 ◽  
Vol 12 (3) ◽  
pp. 4-7
Author(s):  
Charles N. Brooks ◽  
Christopher R. Brigham

Abstract Multiple factors determine the likelihood, type, and severity of bodily injury following a motor vehicle collision and, in turn, influence the need for treatment, extent of disability, and likelihood of permanent impairment. Among the most important factors is the change in velocity due to an impact (Δv). Other factors include the individual's strength and elasticity, body position at the time of impact, awareness of the impending impact (ie, opportunity to brace, guard, or contract muscles before an impact), and effects of braking. Because Δv is the area under the acceleration vs time curve, it combines force and duration and is a useful way to quantify impact severity. The article includes a table showing the results of a literature review that concluded, “the consensus of human subject research conducted to date is that a single exposure to a rear-end impact with a Δv of 5 mph or less is unlikely to result in injury” in most healthy, restrained occupants. Because velocity incorporates direction as well as speed, a vehicular occupant is less likely to be injured in a rear impact than when struck from the side. Evaluators must consider multiple factors, including the occupant's pre-existing physical and psychosocial status, the mechanism and magnitude of the collision, and a variety of biomechanical variables. Recommendations based solely on patient history and physical findings (and, perhaps, imaging studies) may be ill-informed.


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