Influence of Bilateral Vestibular Loss on Spinal Stabilization in Humans

The control of upper body (UB) orientation relative to the pelvis in the frontal plane was characterized in bilateral vestibular loss subjects (BVLs) and compared with healthy control subjects (Cs). UB responses to external perturbations were evoked using continuous pelvis tilts (eyes open and eyes closed) at various amplitudes. Lateral sway of the lower body was prevented on all tests. UB sway was summarized using root-mean-square measures and dynamic behavior was characterized using frequency response functions (FRFs) from 0.023 to 10.3 Hz. Both subject groups had similar FRF variations as a function of stimulus frequency and were relatively unaffected by visual availability, indicating that visual orientation cues contributed very little to UB control. BVLs had larger UB sway at frequencies below ∼1 Hz compared with Cs. A feedback model of UB orientation control was used to identify sensory contributions to spinal stability and differences between subject groups. The model-based interpretation of experimental results indicated that a phasic proprioceptive signal encoding the angular velocity of UB relative to lower body motion was a major contributor to overall system damping. Parametric system identification showed that BVLs used proprioceptive information that oriented the UB toward the pelvis to a greater extent compared with Cs. Both subject groups used sensory information that oriented the UB vertical in space to a greater extent as pelvis tilt amplitudes increased. In BVLs, proprioceptive information signaling the UB orientation relative to the fixed lower body provided the vertical reference, whereas in Cs, vestibular information also contributed to the vertical reference.

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The role of vestibular and somatosensory systems in intersegmental control of upright stance

Journal of Vestibular Research ◽

10.3233/ves-2008-18104 ◽

2008 ◽

Vol 18 (1) ◽

pp. 39-49 ◽

Cited By ~ 3

Author(s):

Rob Creath ◽

Tim Kiemel ◽

Fay Horak ◽

John J. Jeka

Keyword(s):

Support Surface ◽

Light Touch ◽

Upright Stance ◽

Rotating Platform ◽

Vestibular Loss ◽

Bilateral Vestibular Loss ◽

Eyes Closed ◽

Intersegmental Dynamics ◽

Somatosensory Information ◽

Leg Coordination

Upright stance was perturbed using sinusoidal platform rotations to see how vestibular and somatosensory information are used to control segment and intersegmental dynamics in subjects with bilateral vestibular loss (BVL) and healthy controls (C). Subjects stood with eyes closed on a rotating platform (±1.2° for frequencies ranging from 0.01–0.4 Hz in the presence and absence of light fingertip touch. Trunk movement relative to the platform of BVLs was higher than Cs at higher platform frequencies whereas leg movement relative to the platform was similar for both groups. With the addition of light touch, both groups showed similar trunk and leg segment movement relative to the platform. Trunk-leg coordination was in-phase for frequencies below 1 Hz and anti-phase above 1 Hz. Interestingly, BVLs showed evidence of a "legs-leading-trunk" relationship in the shift from in-phase to anti-phase around 1 Hz. Controls showed no preference for either segment to lead the coordinative shift from in- to anti-phase. The results suggest that the balance instability of BVL subjects stems from high variability of the trunk, rather than the legs. The high trunk variability may emerge from the "legs-leading" intersegmental relationship upon which BVLs rely. Because BVLs derive information about self-orientation primarily from the support surface when their eyes are closed, the legs initiate the shift to anti-phase trunk-leg coordination that is necessary for stable upright stance control. Higher trunk variability suggests that this strategy results in lower overall postural stability. Light touch substitutes for vestibular information, leading to lower trunk variability along with a trunk-leg phase shift similar to controls, without a preference for either segment to lead the shift. The results suggest that vestibulospinal control acts primarily to stabilize the trunk in space and to facilitate intersegmental dynamics.

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Using Inertial Sensors to Quantify Postural Sway and Gait Performance during the Tandem Walking Test

Sensors ◽

10.3390/s19040751 ◽

2019 ◽

Vol 19 (4) ◽

pp. 751 ◽

Cited By ~ 2

Author(s):

Kyoung Kim ◽

Yoav Gimmon ◽

Jennifer Millar ◽

Michael Schubert

Keyword(s):

Inertial Sensors ◽

Postural Sway ◽

Upper Body ◽

Lower Body ◽

Gait Control ◽

Walking Test ◽

Gait Performance ◽

Eyes Closed ◽

Vestibular Hypofunction ◽

Eyes Open

Vestibular dysfunction typically manifests as postural instability and gait irregularities, in part due to inaccuracies in processing spatial afference. In this study, we have instrumented the tandem walking test with multiple inertial sensors to easily and precisely investigate novel variables that can distinguish abnormal postural and gait control in patients with unilateral vestibular hypofunction. Ten healthy adults and five patients with unilateral vestibular hypofunction were assessed with the tandem walking test during eyes open and eyes closed conditions. Each subject donned five inertial sensors on the upper body (head, trunk, and pelvis) and lower body (each lateral malleolus). Our results indicate that measuring the degree of balance and gait regularity using five body-worn inertial sensors during the tandem walking test provides a novel quantification of movement that identifies abnormalities in patients with vestibular impairment.

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Influence of Stance Width on Frontal Plane Postural Dynamics and Coordination in Human Balance Control

Journal of Neurophysiology ◽

10.1152/jn.00916.2009 ◽

2010 ◽

Vol 104 (2) ◽

pp. 1103-1118 ◽

Cited By ~ 59

Author(s):

Adam D. Goodworth ◽

Robert J. Peterka

Keyword(s):

Frequency Response ◽

Balance Control ◽

Frontal Plane ◽

Body Motion ◽

Upper Body ◽

Body Sway ◽

Support Surface ◽

Lower Body ◽

Stimulus Amplitude ◽

Postural System

The influence of stance width on frontal plane postural dynamics and coordination in human bipedal stance was studied. We tested the hypothesis that when subjects adopt a narrow stance width, they will rely heavily on nonlinear control strategies and coordinated counter-phase upper and lower body motion to limit center-of-mass (CoM) deviations from upright; as stance increases, the use of these strategies will diminish. Freestanding frontal plane body sway was evoked through continuous pseudorandom rotations of the support surface on which subjects stood with various stimulus amplitudes. Subjects were either eyes open (EO) or closed (EC) and adopted various stance widths. Upper body, lower body, and CoM kinematics were summarized using root-mean-square and peak-to-peak measures, and dynamic behavior was characterized using frequency-response and impulse-response functions. In narrow stance, CoM frequency-response function gains were reduced with increasing stimulus amplitude and in EO compared with EC; in wide stance, gain reductions were much less pronounced. Results show that the narrow stance postural system is nonlinear across stimulus amplitude in both EO and EC conditions, whereas the wide stance postural system is more linear. The nonlinearity in narrow stance is likely caused by an amplitude-dependent sensory reweighting mechanism. Finally, lower body and upper body sway were approximately in-phase at low frequencies (<1 Hz) and out-of-phase at high frequencies (>1 Hz) across all stance widths, and results were therefore inconsistent with the hypothesis that subjects made greater use of coordinated counter-phase upper and lower body motion in narrow compared with wide stance conditions.

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Vestibulo-sympathetic reflex in patients with bilateral vestibular loss

Journal of Applied Physiology ◽

10.1152/japplphysiol.00466.2019 ◽

2019 ◽

Vol 127 (5) ◽

pp. 1238-1244

Author(s):

O. Kuldavletova ◽

P. Denise ◽

G. Quarck ◽

M. Toupet ◽

H. Normand

Keyword(s):

Normal Subjects ◽

Head Position ◽

Neck Flexion ◽

Vascular Effect ◽

Vestibular Loss ◽

Bilateral Vestibular Loss ◽

Eyes Closed ◽

Head Positions ◽

Sympathetic Effect ◽

Sensory Compensation

This study assessed cardiovascular control during head-down neck flexion (HDNF) in a group of patients suffering from total bilateral idiopathic vestibular loss (BVL) for 7 ± 2 yr. Nine adult patients (age 54 ± 6 yr) with BVL were recruited. Calf blood flow (CBF), mean arterial pressure (MAP), and heart rate (HR) were measured with subjects’ eyes closed in two lying body positions: ventral prone (VP) and lateral (LP) on the left side. Vascular resistance (CVR) was calculated as MAP/CBF. The HDNF protocol consisted in passively changing the head position: head up (HU)–head down (HD)–HU. Measurements were taken twice at each head position. In VP CBF significantly decreased in HD (3.65 ± 0.65 mL·min−1·100 mL−1) vs. HU (4.64 ± 0.71 mL·min−1·100 mL−1) ( P < 0.002), whereas CVR in VP significantly rose in HD (31.87 ± 6.93 arbitrary units) vs. HU (25.61 ± 6.36 arbitrary units) ( P < 0.01). In LP no change in CBF or CVR was found between the two head positions. MAP and HR presented no difference between HU and HD in both body positions. Age of patients did not significantly affect the results. The decrease in CBF of the BVL patients was similar to the decrease observed with the same HDNF protocol in normal subjects. This suggests a sensory compensation for the lost vestibular inputs that could originate from the integration of inputs from trunk graviceptors and proprioceptive and cutaneous receptors. Another possibility is that the HDNF vascular effect is evoked mostly by nonlabyrinthine sensors. NEW & NOTEWORTHY The so-called vestibulo-sympathetic reflex, as demonstrated by the head-down neck flexion (HDNF) protocol, is present in patients with total bilateral vestibular idiopathic loss, equally in young and old subjects. The origin of the sympathetic effect of HDNF is questioned. Moreover, the physiological significance of the vestibulo-sympathetic reflex remains obscure, because it acts in opposition to the orthostatic baroreflex. It may serve to inhibit the excessively powerful baroreflex.

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Velocity dependence of vestibular information for postural control on tilting surfaces

Journal of Neurophysiology ◽

10.1152/jn.00057.2016 ◽

2016 ◽

Vol 116 (3) ◽

pp. 1468-1479 ◽

Cited By ~ 9

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.

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Contribution of Sensorimotor Integration to Spinal Stabilization in Humans

Journal of Neurophysiology ◽

10.1152/jn.00118.2009 ◽

2009 ◽

Vol 102 (1) ◽

pp. 496-512 ◽

Cited By ~ 55

Author(s):

Adam D. Goodworth ◽

Robert J. Peterka

Keyword(s):

Visual Information ◽

Time Course ◽

Visual Orientation ◽

Model Parameters ◽

Proprioceptive Information ◽

Time Lags ◽

Impulse Response Functions ◽

Response Functions ◽

Stimulus Amplitude ◽

Eyes Closed

The control of upper body (UB) orientation relative to the pelvis in the frontal plane was characterized by analyzing responses to external perturbations consisting of continuous pelvis tilts (eyes open [EO] and eyes closed [EC]) and visual surround tilts (EO) at various amplitudes. Lateral sway of the lower body was prevented on all tests. UB sway was analyzed by calculating impulse–response functions (IRFs) and frequency–response functions (FRFs) from 0.023 to 10.3 Hz for pelvis tilt tests and FRFs from 0.041 to 1.5 Hz for visual tests. For pelvis tilt tests, differences between FRFs were limited to frequencies <3 Hz and were dependent on stimulus amplitude. IRFs were nearly identical across all pelvis tilt tests for the first 0.2 s, but showed amplitude-dependent changes in their time course at longer time lags. The availability of visual orientation cues (EO vs. EC) had only a small effect on the UB sway during pelvis tilt tests. This small effect of vision was consistent with the small UB sway evoked on visual tilt tests. Experimental results were interpreted using a feedback model of UB orientation control that included time-delayed sensory integration, short-latency reflexive mechanisms, and intrinsic biomechanical properties of the UB. Variation in model parameters indicated that subjects shifted toward reliance on vestibular information and away from proprioceptive information as pelvis tilt amplitudes increased. For visual tilt stimuli, model parameters indicated that subjects shifted toward reliance on vestibular and proprioceptive information and away from visual information as the stimulus amplitude increased.

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Faculty Opinions recommendation of Effectiveness of head-mounted vibrotactile stimulation in subjects with bilateral vestibular loss: a phase 1 clinical trial.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1164123.624796 ◽

2009 ◽

Author(s):

Joseph Furman ◽

Maha Tayseer Mohammad

Keyword(s):

Clinical Trial ◽

Phase 1 ◽

Vibrotactile Stimulation ◽

Vestibular Loss ◽

Phase 1 Clinical Trial ◽

Bilateral Vestibular Loss

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Independent and sensitive gait parameters for objective evaluation in knee and hip osteoarthritis using wearable sensors

BMC Musculoskeletal Disorders ◽

10.1186/s12891-021-04074-2 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Ramon J. Boekesteijn ◽

José M. H. Smolders ◽

Vincent J. J. F. Busch ◽

Alexander C. H. Geurts ◽

Katrijn Smulders

Keyword(s):

Dual Task ◽

Wearable Sensors ◽

Body Motion ◽

Effect Sizes ◽

Upper Body ◽

Healthy Controls ◽

Gait Parameters ◽

Dual Task Cost ◽

Dual Task Performance ◽

Spatiotemporal Parameters

Abstract Background Although it is well-established that osteoarthritis (OA) impairs daily-life gait, objective gait assessments are not part of routine clinical evaluation. Wearable inertial sensors provide an easily accessible and fast way to routinely evaluate gait quality in clinical settings. However, during these assessments, more complex and meaningful aspects of daily-life gait, including turning, dual-task performance, and upper body motion, are often overlooked. The aim of this study was therefore to investigate turning, dual-task performance, and upper body motion in individuals with knee or hip OA in addition to more commonly assessed spatiotemporal gait parameters using wearable sensors. Methods Gait was compared between individuals with unilateral knee (n = 25) or hip OA (n = 26) scheduled for joint replacement, and healthy controls (n = 27). For 2 min, participants walked back and forth along a 6-m trajectory making 180° turns, with and without a secondary cognitive task. Gait parameters were collected using 4 inertial measurement units on the feet and trunk. To test if dual-task gait, turning, and upper body motion had added value above spatiotemporal parameters, a factor analysis was conducted. Effect sizes were computed as standardized mean difference between OA groups and healthy controls to identify parameters from these gait domains that were sensitive to knee or hip OA. Results Four independent domains of gait were obtained: speed-spatial, speed-temporal, dual-task cost, and upper body motion. Turning parameters constituted a gait domain together with cadence. From the domains that were obtained, stride length (speed-spatial) and cadence (speed-temporal) had the strongest effect sizes for both knee and hip OA. Upper body motion (lumbar sagittal range of motion), showed a strong effect size when comparing hip OA with healthy controls. Parameters reflecting dual-task cost were not sensitive to knee or hip OA. Conclusions Besides more commonly reported spatiotemporal parameters, only upper body motion provided non-redundant and sensitive parameters representing gait adaptations in individuals with hip OA. Turning parameters were sensitive to knee and hip OA, but were not independent from speed-related gait parameters. Dual-task parameters had limited additional value for evaluating gait in knee and hip OA, although dual-task cost constituted a separate gait domain. Future steps should include testing responsiveness of these gait domains to interventions aiming to improve mobility.

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Central aortic hemodynamics following acute lower and upper-body exercise in a cold environment among patients with coronary artery disease

Scientific Reports ◽

10.1038/s41598-021-82155-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Heidi E. Hintsala ◽

Rasmus I. P. Valtonen ◽

Antti Kiviniemi ◽

Craig Crandall ◽

Juha Perkiömäki ◽

...

Keyword(s):

Coronary Artery Disease ◽

Coronary Artery ◽

Dynamic Exercise ◽

Upper Body ◽

Cold Environment ◽

Lower Body ◽

Static Exercise ◽

Upper Body Exercise ◽

Post Exercise ◽

Artery Disease

AbstractExercise is beneficial to cardiovascular health, evidenced by reduced post-exercise central aortic blood pressure (BP) and wave reflection. We assessed if post-exercise central hemodynamics are modified due to an altered thermal state related to exercise in the cold in patients with coronary artery disease (CAD). CAD patients (n = 11) performed moderate-intensity lower-body exercise (walking at 65–70% of HRmax) and rested in neutral (+ 22 °C) and cold (− 15 °C) conditions. In another protocol, CAD patients (n = 15) performed static (five 1.5 min work cycles, 10–30% of maximal voluntary contraction) and dynamic (three 5 min workloads, 56–80% of HRmax) upper-body exercise at the same temperatures. Both datasets consisted of four 30-min exposures administered in random order. Central aortic BP and augmentation index (AI) were noninvasively assessed via pulse wave analyses prior to and 25 min after these interventions. Lower-body dynamic exercise decreased post-exercise central systolic BP (6–10 mmHg, p < 0.001) and AI (1–6%, p < 0.001) both after cold and neutral and conditions. Dynamic upper-body exercise lowered central systolic BP (2–4 mmHg, p < 0.001) after exposure to both temperatures. In contrast, static upper-body exercise increased central systolic BP after exposure to cold (7 ± 6 mmHg, p < 0.001). Acute dynamic lower and upper-body exercise mainly lowers post-exercise central BP in CAD patients irrespective of the environmental temperature. In contrast, central systolic BP was elevated after static exercise in cold. CAD patients likely benefit from year-round dynamic exercise, but hemodynamic responses following static exercise in a cold environment should be examined further.Clinical trials.gov: NCT02855905 04/08/2016.

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