Bilateral Vestibular Loss in Cats Leads to Active Destabilization of Balance During Pitch and Roll Rotations of the Support Surface

2007 ◽  
Vol 97 (6) ◽  
pp. 4357-4367 ◽  
Author(s):  
Jane M. Macpherson ◽  
Dirk G. Everaert ◽  
Paul J. Stapley ◽  
Lena H. Ting
Keyword(s):  
Center Of Mass ◽  
The Body ◽  
Support Surface ◽  
Postural Response ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Automatic Postural Response ◽  
Vestibular Information ◽  
Body Center ◽  
Proprioceptive Inputs

Although the balance difficulties accompanying vestibular loss are well known, the underlying cause remains unclear. We examined the role of vestibular inputs in the automatic postural response (APR) to pitch and roll rotations of the support surface in freely standing cats before and in the first week after bilateral labyrinthectomy. Support surface rotations accelerate the body center of mass toward the downhill side. The normal APR consists of inhibition in the extensors of the uphill limbs and excitation in the downhill limbs to decelerate the body and maintain the alignment of the limbs with respect to earth-vertical. After vestibular lesion, cats were unstable during rotation perturbations and actively pushed themselves downhill rather than uphill, using a postural response that was opposite to that seen in the control trials. The extensors of the uphill rather than downhill limbs were activated, whereas those of the downhill limbs were inhibited rather than being excited. We propose that vestibular inputs provide an important reference to earth-vertical, which is critical to computing the appropriate postural response during active orientation to the vertical. In the absence of this vestibular information, subjects orient to the support surface using proprioceptive inputs, which drives the body downhill resulting in instability and falling. This is consistent with current models of sensory integration for computation of body posture and orientation.

Bilateral labyrinthectomy in the cat: effects on the postural response to translation

1995 ◽  
Vol 73 (3) ◽  
pp. 1181-1191 ◽  
Author(s):  
J. T. Inglis ◽  
J. M. Macpherson
Keyword(s):  
Visual Information ◽  
Center Of Mass ◽  
Afferent Input ◽  
Support Surface ◽  
Postural Response ◽  
Automatic Postural Response ◽  
Somatosensory Information ◽  
Postural Responses ◽  
Before And After ◽  
Evoked Activity

1. This study examined the role of vestibular afferent information on the postural responses of four cats, evoked by movements of the support surface during stance. Animals were exposed to linear translations of the supporting surface in eight evenly spaced directions in the horizontal plane, before and after bilateral labyrinthectomy. Postural responses were quantified in terms of the ground reaction forces under each paw and the evoked activity in selected muscles. 2. The cats were able to stand on the platform within 1-3 days after labyrinthectomy and were able to maintain balance during all perturbations of stance, even when they stood in total darkness, completely deprived of visual information. After lesion, postural responses were characterized by normal latency and normal spatial and temporal patterning of electromyographic (EMG) response. The pattern of force response showed the force constraint strategy that characterizes postural responses in the intact animal. 3. The only deficit in the postural response after lesion was a hypermetria, or active over-response that caused the animals to overbalance somewhat but did not impair their ability to remain upright. Analysis of the trajectory of the animal's center of mass during the trials indicated that the hypermetria was due to an abnormally large, active response on the part of the animal and could not be attributed to changes in the passive stiffness of the musculoskeletal system. The hypermetria was transient, and response amplitude returned to control levels after the rapid compensation phase of 10-15 days. 4. It is concluded that vestibular information is not essential for triggering the rapid, automatic postural response to translations of the support surface, nor is it necessary for the selection or shaping of the evoked response. Instead, somatosensory information appears to predominate in these postural adjustments. However, vestibular afferent input does influence the scaling of the postural response.

scholarly journals Velocity dependence of vestibular information for postural control on tilting surfaces

2016 ◽  
Vol 116 (3) ◽  
pp. 1468-1479 ◽  
Author(s):  
Fay B. Horak ◽  
JoAnn Kluzik ◽  
Frantisek Hlavacka
Keyword(s):  
Visual Information ◽  
Postural Sway ◽  
Somatosensory System ◽  
The Body ◽  
Velocity Range ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Eyes Closed ◽  
Vestibular Information ◽  
Wide Range

Vestibular information is known to be important for postural stability on tilting surfaces, but the relative importance of vestibular information across a wide range of surface tilt velocities is less clear. We compared how tilt velocity influences postural orientation and stability in nine subjects with bilateral vestibular loss and nine age-matched, control subjects. Subjects stood on a force platform that tilted 6 deg, toes-up at eight velocities (0.25 to 32 deg/s), with and without vision. Results showed that visual information effectively compensated for lack of vestibular information at all tilt velocities. However, with eyes closed, subjects with vestibular loss were most unstable within a critical tilt velocity range of 2 to 8 deg/s. Subjects with vestibular deficiency lost their balance in more than 90% of trials during the 4 deg/s condition, but never fell during slower tilts (0.25–1 deg/s) and fell only very rarely during faster tilts (16–32 deg/s). At the critical velocity range in which falls occurred, the body center of mass stayed aligned with respect to the surface, onset of ankle dorsiflexion was delayed, and there was delayed or absent gastrocnemius inhibition, suggesting that subjects were attempting to actively align their upper bodies with respect to the moving surface instead of to gravity. Vestibular information may be critical for stability at velocities of 2 to 8 deg/s because postural sway above 2 deg/s may be too fast to elicit stabilizing responses through the graviceptive somatosensory system, and postural sway below 8 deg/s may be too slow for somatosensory-triggered responses or passive stabilization from trunk inertia.

Vestibular loss disrupts control of head and trunk on a sinusoidally moving platform

2002 ◽  
Vol 11 (6) ◽  
pp. 371-389 ◽  
Author(s):  
John J. Buchanan ◽  
Fay B. Horak
Keyword(s):  
Center Of Mass ◽  
Support Surface ◽  
Vestibular Loss ◽  
Trunk Motion ◽  
Bilateral Vestibular Loss ◽  
Somatosensory Information ◽  
Large Head ◽  
Space Pattern ◽  
And Control ◽  
Sinusoidal Surface

Twelve subjects, 6 bilateral vestibular-loss (3 well compensated and 3 poorly compensated) and 6 controls, attempted to maintain balance during anterior-posterior sinusoidal surface translation at 6 different frequencies. For frequencies ≤ 0.25 Hz well compensated and control subjects rode the platform by fixing the head and upper-trunk with respect to the support surface, and for frequencies ≥ 0.75 Hz, these subjects fixed their head/upper-trunk in space. Poorly compensated vestibular subjects showed large head and center of mass variability and were unable to balance at frequencies requiring a head fixed in space pattern. All vestibular subjects were less stable with vision than the controls. Without vision, vestibular subjects experienced more falls than the controls at all frequencies, with falls observed in 61% trials and 16% information is important in stabilizing head and upper-trunk motion in space. Visual and somatosensory information can compensate, in part, for vestibular-loss. The results are discussed in light of models that characterize postural control in a vestibular/visual top-down and somatosensory bottom-up manner.

scholarly journals Effect of foot–floor friction on the external moment about the body center of mass during shuffling gait: a pilot study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takeshi Yamaguchi ◽  
Kei Shibata ◽  
Hiromi Wada ◽  
Hiroshi Kakehi ◽  
Kazuo Hokkirigawa
Keyword(s):  
Friction Surface ◽  
Center Of Mass ◽  
Young Male ◽  
The Body ◽  
Low Friction ◽  
Surface Conditions ◽  
Normal Gait ◽  
External Moment ◽  
Body Center ◽  
Floor Condition

AbstractHerein, we investigated the effect of friction between foot sole and floor on the external forward moment about the body center of mass (COM) in normal and shuffling gaits. Five young male adults walked with normal and shuffling gaits, under low- and high-friction surface conditions. The maximum external forward moment about the COM (MEFM-COM) in a normal gait appeared approximately at initial foot contact and was unaffected by floor condition. However, MEFM-COM in a shuffling gait under high-friction conditions exceeded that under low-friction conditions (p < 0.001). Therein, MEFM-COM increased with an increasing utilized coefficient of friction at initial foot contact; this effect was weaker during a normal gait. These findings indicate that increased friction between foot sole and floor might increase tripping risk during a shuffling gait, even in the absence of discrete physical obstacles.

Long bone cross-sectional geometry

2020 ◽  
pp. 307-320
Author(s):  
Christopher B. Ruff ◽  
Ryan W. Higgins ◽  
Kristian J. Carlson
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Lateral Displacement ◽  
Center Of Mass ◽  
Gait Pattern ◽  
Locomotor Behavior ◽  
The Body ◽  
Long Bone ◽  
Cross Sectional ◽  
Body Center

Long bone diaphyseal cross-sectional geometries reflect the mechanical properties of the bones, and can be used to aid in inferences of locomotor behavior in extinct hominins. This chapter considers all available long bone diaphyseal and femoral neck cross-sections of specimens from Sterkfontein Member 4, and presents comparisons of these section properties and other cross-sectional dimensions with those of other early hominins as well as modern samples. The cross-sectional geometry of the Sterkfontein Member 4 long bone specimens suggests some similarities to, but also interesting differences in, mechanical loading of these elements relative to modern humans. The less asymmetric cortical bone distribution in the Sterkfontein femoral necks is consistent with other evidence above indicating an altered gait pattern involving lateral displacement of the body center of mass over the stance limb. The relatively very strong upper limb of StW 431 implies that arboreal behavior formed a significant component of its locomotor repertoire. Bipedal gait may have been less efficient and arboreal climbing more prevalent in the Sterkfontein hominins.

Time-To-Contact Analysis of Gait Stability in the Swing Phase of Walking in People With Multiple Sclerosis

Motor Control ◽  
2015 ◽  
Vol 19 (4) ◽  
pp. 289-311 ◽  
Author(s):  
Jebb G. Remelius ◽  
Richard E.A. van Emmerik
Keyword(s):  
Multiple Sclerosis ◽  
Center Of Mass ◽  
Swing Phase ◽  
The Body ◽  
Head Movements ◽  
Gait Stability ◽  
Time To Contact ◽  
Prospective Control ◽  
Body Center ◽  
All Speeds

This study investigated timing and coordination during the swing phase of swing leg, body center of mass (CoM) and head during walking people with multiple sclerosis (MS; n = 19) and controls (n = 19). The MS group showed differences in swing phase timing at all speeds. At imposed but not preferred speeds, the MS group had less time to prepare for entry into the unstable equilibrium, as the CoM entered this phase of swing earlier. Time-to-contact coupling, quantifying the coordination between the CoM and the swing foot, was not different between groups. The projection of head motion on the ground occurred earlier after toeoff and was positioned closer to the body in the MS group, illustrating increased reliance on visual exproprioception in which vision of the body in relation to the surface of support is established. Finally, prospective control, linking head movements to the swing foot time-to-contact and next step landing area, was impaired in the MS group at higher gait speeds.

scholarly journals Symmetry Analysis of Amputee Gait Based on Body Center of Mass Trajectory and Discrete Fourier Transform

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2392
Author(s):  
Claudia Ochoa-Diaz ◽  
Antônio Padilha L. Bó
Keyword(s):  
Center Of Mass ◽  
Sine Wave ◽  
The Body ◽  
Compensatory Mechanisms ◽  
Magnitude Spectrum ◽  
Functional Aspects ◽  
Gait Mechanics ◽  
Body Center ◽  
Main Components ◽  
Amputee Gait

The calculation of symmetry in amputee gait is a valuable tool to assess the functional aspects of lower limb prostheses and how it impacts the overall gait mechanics. This paper analyzes the vertical trajectory of the body center of mass (CoM) of a group formed by transfemoral amputees and non-amputees to quantitatively compare the symmetry level of this parameter for both cases. A decomposition of the vertical CoM into discrete Fourier series (DFS) components is performed for each subject’s CoM trajectory to identify the main components of each pattern. A DFS-based index is then calculated to quantify the CoM symmetry level. The obtained results show that the CoM displays different patterns along a gait cycle for each amputee, which differ from the sine-wave shape obtained in the non-amputee case. The CoM magnitude spectrum also reveals more coefficients for the amputee waveforms. The different CoM trajectories found in the studied subjects can be thought as the manifestation of developed compensatory mechanisms, which lead to gait asymmetries. The presence of odd components in the magnitude spectrum is related to the asymmetric behavior of the CoM trajectory, given the fact that this signal is an even function for a non-amputee gait. The DFS-based index reflects this fact due to the high value obtained for the non-amputee reference, in comparison to the low values for each amputee.

scholarly journals Can explicit visual feedback of postural sway efface the effects of sensory manipulations on mediolateral balance performance?

2016 ◽  
Vol 115 (2) ◽  
pp. 907-914 ◽  
Author(s):  
L. Eduardo Cofré Lizama ◽  
Mirjam Pijnappels ◽  
N. Peter Reeves ◽  
Sabine M. P. Verschueren ◽  
Jaap H. van Dieën
Keyword(s):  
Visual Feedback ◽  
Repeated Measures ◽  
Visual Information ◽  
Postural Sway ◽  
Center Of Mass ◽  
The Body ◽  
Body Center ◽  
Explicit Feedback ◽  
Dominant Frequencies ◽  
Visual Conditions

Explicit visual feedback on postural sway is often used in balance assessment and training. However, up-weighting of visual information may mask impairments of other sensory systems. We therefore aimed to determine whether the effects of somatosensory, vestibular, and proprioceptive manipulations on mediolateral balance are reduced by explicit visual feedback on mediolateral sway of the body center of mass and by the presence of visual information. We manipulated sensory inputs of the somatosensory system by transcutaneous electric nerve stimulation on the feet soles (TENS) of the vestibular system by galvanic vestibular stimulation (GVS) and of the proprioceptive system by muscle-tendon vibration (VMS) of hip abductors. The effects of these manipulations on mediolateral sway were compared with a control condition without manipulation under three visual conditions: explicit feedback of sway of the body center of mass (FB), eyes open (EO), and eyes closed (EC). Mediolateral sway was quantified as the sum of energies in the power spectrum and as the energy at the dominant frequencies in each of the manipulation signals. Repeated-measures ANOVAs were used to test effects of each of the sensory manipulations, of visual conditions and their interaction. Overall, sensory manipulations increased body sway compared with the control conditions. Absence of normal visual information had no effect on sway, while explicit feedback reduced sway. Furthermore, interactions of visual information and sensory manipulation were found at specific dominant frequencies for GVS and VMS, with explicit feedback reducing the effects of the manipulations but not effacing these.

Body Segment Contributions to Javelin Throwing during Final Thrust Phases

1994 ◽  
Vol 10 (2) ◽  
pp. 166-177 ◽  
Author(s):  
Mero Antti ◽  
Paavo V. Komi ◽  
Tapio Korjus ◽  
Enrique Navarro ◽  
Robert J. Gregor
Keyword(s):  
High Speed ◽  
Olympic Games ◽  
Center Of Mass ◽  
The Body ◽  
Body Segment ◽  
Male And Female ◽  
Body Center ◽  
Joint Center ◽  
The Right ◽  
Release Speed

This study investigated body segment contributions to javelin throwing during the last thrust phases. A 3-D analysis was performed on male and female javelin throwers during the finals of the 1992 Olympic Games in Barcelona. The subjects were videotaped from the right sight of the throwing area by two NAC high-speed cameras operating at 100 frames per second. Both men’s and women’s grip of javelin and body center of mass displayed a curved pathway to the right from the left (bracing) foot during the final foot contact. The position of the body center of mass decreased at the beginning of the final foot contact, but after the decrease period it began to increase. Simultaneously with the increase, the peak joint center speeds occurred in a proper sequence from proximal to distal segments and finally to the javelin at release. Release speed correlated significantly with throwing distance in both male and females.

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