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Cleworth TW, Allum JHJ, Nielsen EI, Carpenter MG. The Effect of Roll Circular Vection on Roll Tilt Postural Responses and Roll Subjective Postural Horizontal of Healthy Normal Subjects. Brain Sci 2023; 13:1502. [PMID: 38002463 PMCID: PMC10669334 DOI: 10.3390/brainsci13111502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 11/26/2023] Open
Abstract
Background: Falls and related injuries are critical issues in several disease states, as well as aging, especially when interactions between vestibular and visual sensory inputs are involved. Slow support surface tilt (0.6 deg/s) followed by subjective postural horizontal (SPH) assessments have been proposed as a viable method for assessing otolith contributions to balance control. Previous assessments of perceived body alignment to vertical, including subjective visual vertical, have suggested that visual inputs are weighted more when vestibular information is near the threshold and less reliable during slow body tilt. To date, no studies have examined the influence of visual stimuli on slow roll-tilt postural responses and the SPH. Therefore, this study investigated how dynamic visual cues, in the form of circular vection (CV), influence postural responses and the perception of the horizontal during and after support surface tilt. Methods: Ten healthy young adults (6 female, mean age 23) wore a head-mounted display while standing on a tilting platform. Participants were asked to remain upright for 30 s, during which (1) the visual scene rotated, inducing roll CV clockwise (CW) or counter-clockwise (CCW) at 60°/s; (2) the platform only (PO) rotated in roll to test SPH (0.6°/s, 2°, CW or CCW); (3) a combination of both; or (4) neither occurred. During SPH trials, participants used a hand-held device to reset the position of the platform to 0.8°/s to their perceived SPH. The angular motion of body segments was measured using pairs of light-emitting diodes mounted on the head, trunk and pelvis. Segment motion, prior to platform motion, was compared to that at peak body motion induced by platform motion and when SPH had been set. Results: When the support surface was tilted 2°, peak upper body tilt significantly increased for congruent CV and platform tilt and decreased at the pelvis for incongruent CV when compared to PO, leading to significant differences across body segments for congruent and incongruent conditions (p ≤ 0.008). During PO, participants' mean SPH deviated from horizontal by 0.2°. The pelvis deviated 0.2°, the trunk 0.3°, and the head 0.5° in the direction of initial platform rotation. When platform tilt and CV directions were congruent or incongruent, only head tilt at SPH reset under congruent conditions was significantly different from the PO condition (1.7° vs. 0.5°). Conclusions: Roll CV has a significant effect on phasic body responses and a less significant effect on tonic body responses to lateral tilt. The SPH of the support surface was not altered by CV. Responses during tilt demonstrated enhanced reactions for congruent and reduced reactions for incongruent CV, both different from responses to CV alone. Tonic body displacements associated with SPH were changed less than those during tilt and were only slightly larger than displacements for CV alone. This study supports the hypothesis of weighted multisensory integration during dynamic postural tasks being highly dependent on the direction of visual cues during tilt and less dependent on tonic SPH offsets. These techniques could be used to examine vestibular and visual interactions within clinical populations, particularly those with visual vertigo and dizziness.
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Affiliation(s)
- Taylor W. Cleworth
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada;
- Centre for Vision Research, York University, Toronto, ON M3J 1P3, Canada
| | - John H. J. Allum
- Department of Otorhinolaryngology, University of Basel Hospital, CH-4031 Basel, Switzerland
| | - Emma I. Nielsen
- School of Kinesiology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (E.I.N.); (M.G.C.)
| | - Mark G. Carpenter
- School of Kinesiology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (E.I.N.); (M.G.C.)
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The Effect of Unilateral Vestibular Loss on Standing Balance During Postural Threat. Otol Neurotol 2020; 41:e945-e951. [PMID: 32658112 DOI: 10.1097/mao.0000000000002485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Vestibular deficit patients have an increased fall risk and fear of falling. Postural threat, known to increase balance-related fear and anxiety, influences vestibular gains during quiet standing in young healthy adults. The current study examined whether there is a similar relationship for peripheral unilateral vestibular loss (UVL) patients in comparison to age-matched healthy controls (HC). SETTING University laboratory. STUDY DESIGN Prospective laboratory study. PATIENTS AND CONTROLS Eleven UVL patients, nine with vestibular neurectomy. Eleven aged-matched HCs. MAIN OUTCOME MEASURES Subjects stood on a hydraulic lift placed at two heights: low (0.8 m, away from the edge) and high (3.2 m, at the edge). Amplitude (root mean square), mean power frequency (MPF), and mean position were analyzed for center of foot pressure (COP) and 90% ranges for angle amplitude and velocity for trunk sway. RESULTS Group interactions were strongest for anterior-posterior (AP) COP and trunk pitch angle. AP lean away from the edge was greater in HCs than UVLs. HCs, but not UVLs had a decrease in root mean square AP COP with height. Trunk pitch sway was changed similarly. Both groups had increased trunk pitch velocity at height. Changes with height were less for roll: MPF of lateral COP increased with height for UVLs with no changes for HCs, and trunk roll amplitude decreased for both groups. CONCLUSIONS This report provides evidence for a differential effect of height induced postural threat on balance control between UVLs and HCs presumably due to the reduced vestibular-spinal gain in UVL subjects.
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Anson ER, Ehrenburg MR, Wei EX, Bakar D, Simonsick E, Agrawal Y. Saccular function is associated with both angular and distance errors on the triangle completion test. Clin Neurophysiol 2019; 130:2137-2143. [PMID: 31569041 PMCID: PMC6874399 DOI: 10.1016/j.clinph.2019.08.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 08/22/2019] [Accepted: 08/24/2019] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The present study was designed to determine whether healthy older adults with age-related vestibular loss have deficits in spatial navigation. METHODS 154 adults participating in the Baltimore Longitudinal Study of Aging were tested for semicircular canal, saccular, and utricular function and spatial navigation ability using the blindfolded Triangle Completion Test (TCT). Multiple linear regression was used to investigate the relationships between each measure of vestibular function and performance on the TCT (angular error, end point error, and distance walked) while controlling for age and sex. RESULTS Individuals with abnormal saccular function made larger angular errors (β = 4.2°, p < 0.05) and larger end point errors (β = 13.6 cm, p < 0.05). Independent of vestibular function, older age was associated with larger angular (β's = 2.2-2.8°, p's < 0.005) and end point errors (β's = 7.5-9.0 cm, p's < 0.005) for each decade increment in age. CONCLUSIONS Saccular function appears to play a prominent role in accurate spatial navigation during a blindfolded navigation task. SIGNIFICANCE We hypothesize that gravitational cues detected by the saccule may be integrated into estimation of place as well as heading direction.
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Affiliation(s)
- E R Anson
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Otolaryngology, University of Rochester, Rochester, NY, USA.
| | - M R Ehrenburg
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - E X Wei
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - D Bakar
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA; School of Medicine, Brown University, Providence, RI, USA
| | - E Simonsick
- Longitudinal Studies Section, National Institute on Aging, Baltimore, MD, USA
| | - Y Agrawal
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Anson E, Pineault K, Bair W, Studenski S, Agrawal Y. Reduced vestibular function is associated with longer, slower steps in healthy adults during normal speed walking. Gait Posture 2019; 68:340-345. [PMID: 30576978 PMCID: PMC6370495 DOI: 10.1016/j.gaitpost.2018.12.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/04/2018] [Accepted: 12/12/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND Vestibular signals contribute to balance and walking. With aging, vestibular function declines and gait speed decreases. Vestibular loss contributes to decreasing gait speed, but this influence could be linked to spatial and/or temporal aspects of gait. We investigated the relationship between vestibular function (semicircular canal and otolith function) and spatial and temporal gait parameters in a cohort of adults. METHODS 113 community-dwelling healthy adults (mean age 72.2 (14.6) years) participating in the Baltimore Longitudinal Study of Aging were tested. Horizontal semicircular canal (SCC) function was evaluated using quantitative vestibulo-ocular reflex gain. Otolith function was measured with cervical and ocular vestibular evoked myogenic potentials. Gait kinematics were collected during normal speed walking. Multiple linear regressions examined the association between spatial and temporal gait parameters and SCC and otolith function separately, controlling for age, gender, height, and either cadence (for spatial gait outcomes) or stride length (for temporal gait outcomes) to account for gait speed effects. RESULTS Vestibular SCC function was significantly associated with both spatial and temporal gait parameters. Every 0.1 decrease in SCC function resulted in longer stride length (β = -.04 m, p = 0.004), longer stance time (β = 15.8 ms, p < 0.003), and a slower cadence (β = -2.1 steps/minute, p < 0.001). Otolith function was not associated with any gait parameter. CONCLUSIONS Reduced horizontal SCC function was associated with longer, slower steps in a cohort of healthy adults. These results indicate that vestibular signals contribute to specific spatial and temporal aspects of gait thought to contribute to upright balance.
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Affiliation(s)
- E Anson
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Otolaryngology, University of Rochester, Rochester, NY, USA.
| | - K Pineault
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - W Bair
- Longitudinal Studies Section, National Institute on Aging, Baltimore, MD, USA
| | - S Studenski
- Longitudinal Studies Section, National Institute on Aging, Baltimore, MD, USA
| | - Y Agrawal
- Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Vibert D, Allum JHJ, Kompis M, Wiedmer S, Stieger C, Häusler R, Caversaccio M. Measurements of Trunk Sway for Stance and Gait Tasks 2 Years after Vestibular Neurectomy. Audiol Neurootol 2018; 23:298-308. [PMID: 30541000 DOI: 10.1159/000494965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 10/29/2018] [Indexed: 11/19/2022] Open
Abstract
The aim of this study was to investigate changes in balance control for stance and gait tasks in patients 2 years before and after vestibular neurectomy (VN) performed to alleviate intractable Meniere's disease. Amplitudes of trunk sway in roll and pitch directions were measured for stance and gait tasks in 19 patients using gyroscopes mounted at the lower-back. Measurements before VN and 2 years later were compared to those of healthy age-matched controls (HC). We also examined if changes in trunk sway amplitudes were correlated with patients' subjective assessment of disability using the AAO-HNS scale. For patients with low AAO-HNS scores 0-2 (n = 14), trunk roll and pitch sway velocities, standing eyes closed on foam, increased 2 years post VN compared to HC values (p < 0.01). Trunk sway amplitudes remained at levels of HC for simple gait tasks, but task durations were longer and therefore gait slower. For complex gait tasks (stairs), balance control remained impaired at 2 years. In patients with AAO-HNS high scores level 6 (n = 5), balance control remained abnormal, compared to HC, 2 years postoperatively for all stance, several simple and all complex gait tasks. Trunk sway in the pitch and roll directions for stance tasks was correlated with clinical (AAO-HNS) scores (p ≤ 0.05). These results indicate that VN leads to chronic balance problems for stance and complex gait tasks. The problems are greater for patients with high compared to low AAO-HNS scores, thereby explaining the different symptoms reported by these patients. The lack of balance recovery in VN patients to levels of HCs after 2 years contrasts with the 3 months average recovery period for acute vestibular neuritis patients and is indicative of the effects of neurectomy on central compensation processes.
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Affiliation(s)
- Dominique Vibert
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland,
| | - John H J Allum
- Division of Audiology and Neurootology, Department of ORL, University of Basel Hospital, Basel, Switzerland
| | - Martin Kompis
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Simona Wiedmer
- ARTORG Center for Artificial Hearing Research, University of Bern, Bern, Switzerland
| | - Christof Stieger
- ARTORG Center for Artificial Hearing Research, University of Bern, Bern, Switzerland
| | - Rudolf Häusler
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marco Caversaccio
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Precision of perceived direction of gravity in partial bilateral vestibulopathy correlates with residual utricular function. Clin Neurophysiol 2018; 129:934-945. [DOI: 10.1016/j.clinph.2018.02.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 01/05/2018] [Accepted: 02/09/2018] [Indexed: 11/16/2022]
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Isaac V, Olmedo D, Aboitiz F, Delano PH. Altered Cervical Vestibular-Evoked Myogenic Potential in Children with Attention Deficit and Hyperactivity Disorder. Front Neurol 2017; 8:90. [PMID: 28348547 PMCID: PMC5346589 DOI: 10.3389/fneur.2017.00090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/24/2017] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Emerging evidence suggests that children with attention deficit and hyperactivity disorder (ADHD) present more difficulties in standing and walking balance than typically developing children. Most of previous studies have assessed these functions using postural and sensory organization tests showing differences in balance performance between control and ADHD children. However, to date, it is unknown whether these balance alterations are accompanied with vestibular dysfunction. The principal aim of this study is to evaluate vestibular otolith function in ADHD and matched control children. METHODS We assessed vestibular otolith function in children with ADHD and controls using the subjective visual vertical (SVV) bucket test and cervical vestibular-evoked myogenic potentials (cVEMPs). In addition, gait and balance were evaluated using the dynamic gait index (DGI) and computerized posturography. RESULTS Non-significant differences between groups were obtained in SVV evaluation. DGI results show lower scores for overall test performance in children with ADHD (p < 0.001), while computerized postural recordings showed significant differences for the limit of stability between groups (p = 0.02). cVEMPs in response to 500 Hz tone bursts presented at 100 dB were absent or reduced in children with ADHD, as revealed by differences in P1 and N1 peak-to-peak amplitudes between groups (p < 0.01). CONCLUSION These findings suggest that vestibular brainstem reflexes are altered in a subset of children with ADHD. We propose to include cVEMP reflexes in the clinical evaluation of ADHD patients.
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Affiliation(s)
- Valeria Isaac
- Otolaryngology Department, Clinical Hospital of the University of Chile, Santiago, Chile; Pediatric Diagnostic and Therapy Center, CERIL, Santiago, Chile
| | - Diego Olmedo
- Otolaryngology Department, Clinical Hospital of the University of Chile , Santiago , Chile
| | - Francisco Aboitiz
- Departamento de Psiquiatría and Centro Interdisciplinario de Neurociencia, Pontificia Universidad Católica de Chile , Santiago , Chile
| | - Paul H Delano
- Otolaryngology Department, Clinical Hospital of the University of Chile, Santiago, Chile; Physiology and Biophysics, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
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Relation Between Head Impulse Tests, Rotating Chair Tests, and Stance and Gait Posturography After an Acute Unilateral Peripheral Vestibular Deficit. Otol Neurotol 2013; 34:980-9. [DOI: 10.1097/mao.0b013e31829ce5ec] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Menant JC, St George RJ, Fitzpatrick RC, Lord SR. Perception of the postural vertical and falls in older people. Gerontology 2012; 58:497-503. [PMID: 22759640 DOI: 10.1159/000339295] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 05/07/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Research on the relationship between vestibular function and falls in older people is sparse. The perception of the postural vertical (PPV) provides an indicator measure of vestibular (otolith) function in the absence of visual input and diminished somatosensory feedback. OBJECTIVE This study examined whether impaired PPV is associated with falls in this group. METHODS One hundred and ninety-five people aged 70 plus years stood blindfolded on a motorised platform that could be tilted in the roll plane and attempted to adjust it so that their bodies were aligned to the vertical. Somatosensory feedback was minimised as the base and vertical support surfaces on the tilting platform were covered in thick soft foam rubber. PPV error from true vertical and PPV variability (°) were calculated. Participants also underwent an assessment of distal tactile sensitivity and the physiological profile assessment (PPA); fallers were defined as those who had one or more falls during a prospective 12-month follow-up period. RESULTS Eighty-eight participants (45%) reported falling in the follow-up year. Increased PPV error and variability were correlated with increased lateral sway in a condition of absent visual input and reduced foot somatosensory feedback (eyes closed/foam; r range = 0.16-0.20, p < 0.05) and with composite PPA fall risk scores (r range = 0.22-0.26, p < 0.05). PPV variability was a significant and independent predictor of falls after adjusting for the composite PPA scores, age and gender [adjusted RR = 1.42 (1.01-1.98)]. CONCLUSIONS Older people with increased PPV variability are at increased risk of falls. These findings indicate that assessment of PPV may augment fall risk assessments in older people.
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Affiliation(s)
- Jasmine C Menant
- Neuroscience Research Australia, University of New South Wales, Sydney, N.S.W., Australia
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Allum JHJ. Recovery of vestibular ocular reflex function and balance control after a unilateral peripheral vestibular deficit. Front Neurol 2012; 3:83. [PMID: 22623921 PMCID: PMC3353232 DOI: 10.3389/fneur.2012.00083] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/26/2012] [Indexed: 11/19/2022] Open
Abstract
This review describes the effect of unilateral peripheral vestibular deficit (UPVD) on balance control for stance and gait tests. Because a UPVD is normally defined based on vestibular ocular reflex (VOR) tests, we compared recovery observed in balance control with patterns of recovery in VOR function. Two general types of UPVD are considered; acute vestibular neuritis (AVN) and vestibular neurectomy. The latter was subdivided into vestibular loss after cerebellar pontine angle tumor surgery during which a vestibular neurectomy was performed, and vestibular loss following neurectomy to eliminate disabling Ménière's disease. To measure balance control, body-worn gyroscopes, mounted near the body's center of mass (CoM), were used. Measurement variables were the pitch (anterior-posterior) and roll (lateral) sway angles and angular velocities of the lower trunk/pelvis. Both patient groups showed balance deficits during stance tasks on foam, especially with eyes closed when stable balance control is normally highly dependent on vestibular inputs. Deficits during gait were also present and were more profound for complex gait tasks such as tandem gait than simple gait tasks. Major differences emerged between the groups concerning the severity of the deficit and its recovery. Generally, the effects of acute neuritis on balance control were more severe but recovered rapidly. Deficits due to vestibular neurectomy were less severe, but longer lasting. These results mostly paralleled recovery of deficits in VOR function. However, questions need to be raised about the effect on balance control of the two modes of neural plasticity occurring in the vestibular system following vestibular loss due to neuritis: one mode being the limited central compensation for the loss, and the second mode being some restoration of peripheral vestibular function. Future work will need to correlate deficits in balance control during stance and gait more exactly with VOR deficits and carefully consider the differences between insufficient central compensation compared to inadequate peripheral restoration of function.
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Affiliation(s)
- J. H. J. Allum
- Division of Audiology and Neurootology, Department of ORL, University Hospital of BaselBasel, Switzerland
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Cohen B, Xiang Y, Yakushin SB, Kunin M, Raphan T, Minor L, Della Santina CC. Effect of canal plugging on quadrupedal locomotion in monkey. Ann N Y Acad Sci 2009; 1164:89-96. [PMID: 19645885 DOI: 10.1111/j.1749-6632.2009.03845.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The vestibular system plays an important role in controling gait, but where in the labyrinths relevant activity arises is largely unknown. After the semicircular canals are plugged, low frequency (0.01-2 Hz) components of the angular vestibulo-ocular reflex (aVOR) and angular vestibulo-collic reflex (aVCR) are lost, but high frequency (3-20 Hz) components remain. We determined how loss of low frequency canal afference affects limb and head movements during quadrupedal locomotion. Head, body, and limb movements were recorded in three dimensions (3-D) in a cynomolgus monkey with a motion detection system, while the animal walked on a treadmill. All six canals were plugged, reducing the canal time constants from approximately 4.0 sec to approximately 0.07 sec. Major changes in the control of the limbs occurred after surgery. Fore and hind limbs were held farther from the body, producing a broad-based gait. Swing-phase trajectories were inaccurate, and control of medial-lateral limb movement was erratic. These changes in gait were present immediately after surgery, as well as 15 months later, when the animal had essentially recovered. Thus, control of the limbs in the horizontal plane was defective after loss of the low-frequency semicircular canal input and never recovered. Cycle-averaged pitch and roll head rotations, and 3-D head translations were also significantly larger and more erratic after than before surgery. Head rotations in yaw could not be quantified due to intrusion of voluntary head turns. These findings indicate that the semicircular canals provide critical low frequency information to maximize the accuracy of stepping and stabilize the head during normal quadrupedal locomotion.
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Affiliation(s)
- Bernard Cohen
- Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Küng UM, Horlings CGC, Honegger F, Allum JHJ. Incorporating voluntary unilateral knee flexion into balance corrections elicited by multi-directional perturbations to stance. Neuroscience 2009; 163:466-81. [PMID: 19505537 DOI: 10.1016/j.neuroscience.2009.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 05/20/2009] [Accepted: 06/04/2009] [Indexed: 11/24/2022]
Abstract
Positive effects on lateral center of mass (CoM) shifts during balance recovery have been seen with voluntarily unilateral arm raising but not with voluntarily bilateral knee flexion. To determine whether unilateral voluntary knee movements can be effectively incorporated into balance corrections we perturbed the balance of 30 young healthy subjects using multi-directional rotations of the support surface while they simultaneously executed unilateral knee flexion. Combined pitch and roll rotations (7.5 degrees and 60 degrees/s) were presented randomly in six different directions. Subjects were tested in four stance conditions: balance perturbation only (PO); cued flexion of one knee only (KO); combined support surface rotation and cued (at rotation onset) flexion of the uphill knee, contralateral to tilt (CONT), or of the downhill knee, ipsilateral to tilt (IPS). Outcome measures were CoM motion and biomechanical and electromyography (EMG) responses of the legs, arms and trunk. Predicted measures (PO+KO) were compared with combined measures (CONT or IPS). Unilateral knee flexion of the uphill knee (CONT) provided considerable benefit in balance recovery. Subjects rotated their pelvis more to the uphill side than predicted. Downhill knee bending (IPS) also had a positive effect on CoM motion because of a greater than predicted simultaneous lateral shift of the pelvis uphill. KO leg muscle activity showed anticipatory postural activity (APA) with similar profiles to early balance correcting responses. Onsets of muscle responses and knee velocities were earlier for PO, CONT, and IPS compared to KO conditions. EMG response amplitudes for CONT and IPS conditions were generally not different from the PO condition and therefore smaller than predicted. Later stabilizing responses at 400 ms had activation amplitudes generally equal to those predicted from the PO+KO conditions. Our results suggest that because EMG patterns of anticipatory postural activity of voluntary unilateral knee flexion and early balance corrections have similar profiles, the CNS is easily able to incorporate voluntary activation associated with unilateral knee flexion into automatic postural responses. Furthermore, the effect on movement strategies appears to be non-linear. These findings may have important implications for the rehabilitation of balance deficits.
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Affiliation(s)
- U M Küng
- Department of ORL, University Hospital, Basel, Switzerland
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Bunday KL, Bronstein AM. Visuo-vestibular Influences on the Moving Platform Locomotor Aftereffect. J Neurophysiol 2008; 99:1354-65. [PMID: 18184886 DOI: 10.1152/jn.01214.2007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
After walking onto a moving platform subjects experience a locomotor aftereffect (LAE), including a self-generated stumble, when walking again onto a stationary platform. Thus this LAE affords examination of the role of vestibular input during an internally generated postural challenge. The experiments involved walking onto the stationary sled (BEFORE trials), walking onto the moving sled (MOVING), and a second set of stationary trials (AFTER). We investigated 9 bilateral labyrinthine defective subjects (LDS) and 13 age-matched normal controls (NC) with eyes open. We repeated the experiment in 5 NC and 5 LDS but this time the AFTER trials were performed twice, first eyes closed and then on eye reopening. During MOVING trials, LDS were considerably unstable, thus confirming the established role of the vestibular system during externally imposed postural perturbations. During AFTER trials, both groups experienced an aftereffect with eyes open and closed, shown as higher approach gait velocity, a forward trunk overshoot, and increased leg EMG. However, there were no significant group differences due to the fact that stopping the forward trunk overshoot was accomplished by anticipatory EMG bursts. On eye reopening the aftereffect reemerged, significantly larger in LDS than that in NC. The lack of group differences in AFTER trials suggests that when facing internally generated postural perturbations, as in this adaptation process, the CNS relies less on vestibular feedback and more on anticipatory mechanisms. Reemergence of the aftereffect on eye reopening indicates the existence of a feedforward visuo-contextual mechanism for locomotor learning, which is adaptively enhanced in the absence of vestibular function.
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Grin L, Frank J, Allum JHJ. The effect of voluntary arm abduction on balance recovery following multidirectional stance perturbations. Exp Brain Res 2006; 178:62-78. [PMID: 17051384 DOI: 10.1007/s00221-006-0711-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Accepted: 09/09/2006] [Indexed: 10/24/2022]
Abstract
The goal of this study was to investigate how voluntarily abducting one arm, 90 degrees at onset of a rotational perturbation of the support surface, influences the recovery of upright stance. Young adults were tested under four stance conditions: abducting one arm to the horizontal only (AO); perturbation of stance using a support surface rotation only (PO); combined support surface rotation and abduction of the downhill arm, ipsilateral to tilt (IPS); and fourth abduction of the uphill, contralateral arm (CON). Simultaneous auditory and visual trigger cues were used for arm raising. Perturbations consisted of six directions of combined support surface roll and pitch rotation (7.5 degrees and 60 degrees/s). Outcome measures were whole body centre of mass (COM) movements and body segment angular displacements recorded with a motion analysis system, as well as leg, trunk, and arm EMG responses. Arm raises contralateral and ipsilateral to the direction of support surface roll were more rapid than in the AO condition and significantly reduced or increased, respectively, COM lateral displacements relative to the PO condition. The changes in COM displacements and velocities during combined CON arm raise and perturbation were greater than expected from the sum of displacements for AO and PO conditions alone, but less for the IPS condition. Arm raising increased trunk roll in a direction opposite arm raising was more than for the AO and PO conditions. Robust effects were also observed for hip abduction but not for leg flexion. Early balance correcting activity was enhanced on the side opposite arm raising and later stabilising activity reduced bilaterally in lower trunk muscles compared to summed activity for the AO and PO conditions. Similar effects were observed in gluteus medius muscles but effects were weak in ankle muscles. EMG onsets in muscles of the raised arm were earlier than in the AO conditions. We conclude that triggered arm abduction, contralateral to the direction of support surface rotation, had significant stabilization benefits for young adults and ipsilateral arm movements had destabilizing effects. The arm raises could be simultaneously executed with balance corrections. These results provide insights into the integration of balance corrections and voluntary commands into one automatic reaction that may be useful in training fall avoidance.
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Affiliation(s)
- Laura Grin
- Department of ORL, University Hospital, Petersgraben 4, 4031, Basel, Switzerland
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