1
|
Xavier F, Chouin E, Tighilet B, Chabbert C, Besnard S. Innovative approaches for managing patients with chronic vestibular disorders: follow-up indicators and predictive markers for studying the vestibular error signal. FRONTIERS IN REHABILITATION SCIENCES 2024; 5:1414198. [PMID: 39220608 PMCID: PMC11362045 DOI: 10.3389/fresc.2024.1414198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 07/08/2024] [Indexed: 09/04/2024]
Abstract
Introduction Despite significant advancements in understanding the biochemical, anatomical, and functional impacts of vestibular lesions, developing standardized and effective rehabilitation strategies for patients unresponsive to conventional therapies remains a challenge. Chronic vestibular disorders, characterized by permanent or recurrent imbalances and blurred vision or oscillopsia, present significant complexity in non-pharmacological management. The complex interaction between peripheral vestibular damage and its impact on the central nervous system (CNS) raises questions about neuroplasticity and vestibular compensation capacity. Although fundamental research has examined the consequences of lesions on the vestibular system, the effect of a chronic peripheral vestibular error signal (VES) on the CNS remains underexplored. The VES refers to the discrepancy between sensory expectations and perceptions of the vestibular system has been clarified through recent engineering studies. This deeper understanding of VES is crucial not only for vestibular physiology and pathology but also for designing effective measures and methods of vestibular rehabilitation, shedding light on the importance of compensation mechanisms and sensory integration. Methods This retrospective study, targeting patients with chronic unilateral peripheral vestibulopathy unresponsive to standard treatments, sought to exclude any interference from pre-existing conditions. Participants were evaluated before and after a integrative vestibular exploratory and rehabilitation program through questionnaires, posturographic tests, and videonystagmography. Results The results indicate significant improvements in postural stability and quality of life, demonstrating positive modulation of the CNS and an improvement of vestibular compensation. Discussion Successful vestibular rehabilitation likely requires a multifaceted approach that incorporates the latest insights into neuroplasticity and sensory integration, tailored to the specific needs and clinical progression of each patient. Focusing on compensating for the VES and enhancing sensory-perceptual-motor integration, this approach aims not just to tailor interventions but also to reinforce coherence among the vestibular, visual, and neurological systems, thereby improving the quality of life for individuals with chronic vestibular disorders.
Collapse
Affiliation(s)
- Frédéric Xavier
- Sensory and Cognitive Neuroscience Unit LNC UMR 7231 CNRS, Aix-Marseille University, Marseille, France
- Pathophysiology and Therapy of Vestibular Disorders Unit GDR 2074, Aix-Marseille University, Marseille, France
| | - Emmanuelle Chouin
- Pathophysiology and Therapy of Vestibular Disorders Unit GDR 2074, Aix-Marseille University, Marseille, France
| | - Brahim Tighilet
- Sensory and Cognitive Neuroscience Unit LNC UMR 7231 CNRS, Aix-Marseille University, Marseille, France
- Pathophysiology and Therapy of Vestibular Disorders Unit GDR 2074, Aix-Marseille University, Marseille, France
| | - Christian Chabbert
- Sensory and Cognitive Neuroscience Unit LNC UMR 7231 CNRS, Aix-Marseille University, Marseille, France
- Pathophysiology and Therapy of Vestibular Disorders Unit GDR 2074, Aix-Marseille University, Marseille, France
| | - Stéphane Besnard
- Pathophysiology and Therapy of Vestibular Disorders Unit GDR 2074, Aix-Marseille University, Marseille, France
- UNICAEN, INSERM U1075, COMETE, Normandie Université, Caen, France
| |
Collapse
|
2
|
Debenham MIB, Bruce CB, McNeil CJ, Dalton BH. The effects of four hours of normobaric hypoxia on the vestibular control of balance. Exp Brain Res 2024:10.1007/s00221-024-06905-9. [PMID: 39147911 DOI: 10.1007/s00221-024-06905-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 07/30/2024] [Indexed: 08/17/2024]
Abstract
Whole-body vestibular-evoked balance responses decrease following ~ 55 min of normobaric hypoxia. It is unclear how longer durations of hypoxia affect the vestibular control of balance at the muscle and whole-body levels. This study examined how four hours of normobaric hypoxia influenced the vestibular control of balance. Fifteen participants (4 females; 11 males) stood on a force plate with vision occluded and head rotated rightward while subjected to three blocks of binaural, bipolar stochastic electrical vestibular stimulation (EVS; 0-25 Hz, root mean square amplitude = 1.1 mA) consisting of two, 90-s trials. The relationship between EVS and anteroposterior (AP) forces or medial gastrocnemius (MG) electromyography (EMG) was estimated in the time and frequency domains at baseline (BL; 0.21 fraction of inspired oxygen-FIO2) and following two (H2) and four (H4) hours of normobaric hypoxia (0.11 FIO2). The EVS-MG EMG short-latency peak and peak-to-peak amplitudes were smaller than BL at H2 and H4, but the medium-latency peak amplitude was only lower at H4. The EVS-AP force medium-latency peak amplitude was lower than BL at H4, but the short-latency peak and peak-to-amplitudes were unchanged. The EVS-MG EMG coherence and gain were reduced compared to BL at H2 and H4 across multiple frequencies ≥ 7 Hz, whereas EVS-AP force coherence was blunted at H4 (≤ 4 Hz), but gain was unaffected. Overall, the central nervous system's response to vestibular-driven signals during quiet standing was decreased for up to four hours of normobaric hypoxia, and vestibular-evoked responses recorded within postural muscles may be more sensitive than the whole-body response.
Collapse
Affiliation(s)
- M I B Debenham
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, The University of British Columbia, Okanagan Campus, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada
| | - C B Bruce
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, The University of British Columbia, Okanagan Campus, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada
| | - C J McNeil
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, The University of British Columbia, Okanagan Campus, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada
| | - B H Dalton
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, The University of British Columbia, Okanagan Campus, 1147 Research Road, Kelowna, BC, V1V 1V7, Canada.
| |
Collapse
|
3
|
Leeuwis M, Asar Y, White JJ, Rasman BG, Forbes PA. Different mechanisms of contextual inference govern associatively learned and sensory-evoked postural responses. Proc Natl Acad Sci U S A 2024; 121:e2404909121. [PMID: 39093946 PMCID: PMC11317596 DOI: 10.1073/pnas.2404909121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 06/30/2024] [Indexed: 08/04/2024] Open
Abstract
Human standing balance relies on the continuous monitoring and integration of sensory signals to infer our body's motion and orientation within the environment. However, when sensory information is no longer contextually relevant to balancing the body (e.g., when sensory and motor signals are incongruent), sensory-evoked balance responses are rapidly suppressed, much earlier than any conscious perception of changes in balance control. Here, we used a robotic balance simulator to assess whether associatively learned postural responses are similarly modulated by sensorimotor incongruence and contextual relevance to postural control. Twenty-nine participants in three groups were classically conditioned to generate postural responses to whole-body perturbations when presented with an initially neutral sound cue. During catch and extinction trials, participants received only the auditory stimulus but in different sensorimotor states corresponding to their group: 1) during normal active balance, 2) while immobilized, and 3) throughout periods where the computer subtly removed active control over balance. In the balancing and immobilized states, conditioned responses were either evoked or suppressed, respectively, according to the (in)ability to control movement. Following the immobilized state, conditioned responses were renewed when balance was restored, indicating that conditioning was retained but only expressed when contextually relevant. In contrast, conditioned responses persisted in the computer-controlled state even though there was no causal relationship between motor and sensory signals. These findings suggest that mechanisms responsible for sensory-evoked and conditioned postural responses do not share a single, central contextual inference and assessment of their relevance to postural control, and may instead operate in parallel.
Collapse
Affiliation(s)
- Matto Leeuwis
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam3015 GD, The Netherlands
| | - Yomna Asar
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam3015 GD, The Netherlands
| | - Joshua J. White
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam3015 GD, The Netherlands
| | - Brandon G. Rasman
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam3015 GD, The Netherlands
- Department of Sensorimotor Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen6525 GD, The Netherlands
| | - Patrick A. Forbes
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam3015 GD, The Netherlands
| |
Collapse
|
4
|
Gur-Hartman T, Tarrasch R, Zerem A, Sokol-Novinsky R, Elyoseph Z, Lerman-Sagie T, Mintz M. Consequences of vestibular hypofunction in children with ADHD/DCD. Eur J Paediatr Neurol 2024; 52:1-9. [PMID: 38968910 DOI: 10.1016/j.ejpn.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 05/20/2024] [Accepted: 06/20/2024] [Indexed: 07/07/2024]
Abstract
BACKGROUND Children with Attention Deficit Hyperactivity Disorder (ADHD) demonstrate a heterogeneous sensorimotor, emotional, and cognitive profile. Comorbid sensorimotor imbalance, anxiety, and spatial disorientation are particularly prevalent among their non-core symptoms. Studies in other populations presented these three comorbid dysfunctions in the context of vestibular hypofunction. OBJECTIVE To test whether there is a subgroup of children with ADHD who have vestibular hypofunction presenting with concomitant imbalance, anxiety, and spatial disorientation. METHODS Children with ADHD-only (n = 28), ADHD + Developmental Coordination Disorder (ADHD + DCD; n = 38), and Typical Development (TD; n = 19) were evaluated for vestibular function by the Dynamic Visual Acuity test (DVA-t), balance by the Bruininks-Oseretsky Test of motor proficiency (BOT-2), panic anxiety by the Screen for Child Anxiety Related Emotional Disorders questionnaire-Child version (SCARED-C), and spatial navigation by the Triangular Completion test (TC-t). RESULTS Children with ADHD vs. TD presented with a high rate of vestibular hypofunction (65 vs. 0 %), imbalance (42 vs. 0 %), panic anxiety (27 vs. 11 %), and spatial disorientation (30 vs. 5 %). Children with ADHD + DCD contributed more frequent and severe vestibular hypofunction and imbalance than children with ADHD-only (74 vs. 54 %; 58 vs. 21 %, respectively). A concomitant presence of imbalance, anxiety, and spatial disorientation was observed in 33 % of children with ADHD, all sharing vestibular hypofunction. CONCLUSIONS Vestibular hypofunction may be the common pathophysiology of imbalance, anxiety, and spatial disorientation in children. These comorbidities are preferentially present in children with ADHD + DCD rather than ADHD-only, thus likely related to DCD rather than to ADHD disorder. Children with this profile may benefit from a vestibular rehabilitation intervention.
Collapse
Affiliation(s)
- Tamar Gur-Hartman
- School of Psychological Sciences, Tel Aviv University, Israel; Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel.
| | - Ricardo Tarrasch
- Sagol School of Neuroscience, Tel Aviv University, Israel; School of Education, Tel Aviv University, Israel
| | - Ayelet Zerem
- Sackler Faculty of Medicine, Tel Aviv University, Israel; Pediatric Neurology Institute, Dana-Dwek Children's Hospital, Sourasky Medical Center, Tel Aviv, Israel
| | - Riki Sokol-Novinsky
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel; Sackler Faculty of Medicine, Tel Aviv University, Israel
| | | | - Tally Lerman-Sagie
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel; Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Matti Mintz
- School of Psychological Sciences, Tel Aviv University, Israel; Sagol School of Neuroscience, Tel Aviv University, Israel
| |
Collapse
|
5
|
Rasman BG, Blouin JS, Nasrabadi AM, van Woerkom R, Frens MA, Forbes PA. Learning to stand with sensorimotor delays generalizes across directions and from hand to leg effectors. Commun Biol 2024; 7:384. [PMID: 38553561 PMCID: PMC10980713 DOI: 10.1038/s42003-024-06029-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 03/08/2024] [Indexed: 04/02/2024] Open
Abstract
Humans receive sensory information from the past, requiring the brain to overcome delays to perform daily motor skills such as standing upright. Because delays vary throughout the body and change over a lifetime, it would be advantageous to generalize learned control policies of balancing with delays across contexts. However, not all forms of learning generalize. Here, we use a robotic simulator to impose delays into human balance. When delays are imposed in one direction of standing, participants are initially unstable but relearn to balance by reducing the variability of their motor actions and transfer balance improvements to untrained directions. Upon returning to normal standing, aftereffects from learning are observed as small oscillations in control, yet they do not destabilize balance. Remarkably, when participants train to balance with delays using their hand, learning transfers to standing with the legs. Our findings establish that humans use experience to broadly update their neural control to balance with delays.
Collapse
Affiliation(s)
- Brandon G Rasman
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, BC, Canada
| | - Amin M Nasrabadi
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Remco van Woerkom
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Maarten A Frens
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Patrick A Forbes
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
| |
Collapse
|
6
|
Gallina A, Abboud J, Blouin JS. Vestibular control of deep and superficial lumbar muscles. J Neurophysiol 2024; 131:516-528. [PMID: 38230879 DOI: 10.1152/jn.00171.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 11/20/2023] [Accepted: 12/26/2023] [Indexed: 01/18/2024] Open
Abstract
The active control of the lumbar musculature provides a stable platform critical for postures and goal-directed movements. Voluntary and perturbation-evoked motor commands can recruit individual lumbar muscles in a task-specific manner according to their presumed biomechanics. Here, we investigated the vestibular control of the deep and superficial lumbar musculature. Ten healthy participants were exposed to noisy electrical vestibular stimulation while balancing upright with their head facing forward, left, or right to characterize the differential modulation in the vestibular-evoked lumbar extensor responses in generating multidirectional whole body motion. We quantified the activation of the lumbar muscles on the right side using indwelling [deep multifidus, superficial multifidus, caudal longissimus (L4), and cranial longissimus (L1)] and high-density surface recordings. We characterized the vestibular-evoked responses using coherence and peak-to-peak cross-covariance amplitude between the vestibular and electromyographic signals. Participants exhibited responses in all lumbar muscles. The vestibular control of the lumbar musculature exhibited muscle-specific modulations: responses were larger in the longissimus (combined cranio-caudal) compared with the multifidus (combined deep-superficial) when participants faced forward (P < 0.001) and right (P = 0.011) but not when they faced left. The high-density surface recordings partly supported this observation: the location of the responses was more lateral when facing right compared with left (P < 0.001). The vestibular control of muscle subregions within the longissimus or the multifidus was similar. Our results demonstrate muscle-specific vestibular control of the lumbar muscles in response to perturbations of vestibular origin. The lack of differential activation of lumbar muscle subregions suggests the vestibular control of these subregions is co-regulated for standing balance.NEW & NOTEWORTHY We investigated the vestibular control of the deep and superficial lumbar extensor muscles using electrical vestibular stimuli. Vestibular stimuli elicited preferential activation of the longissimus muscle over the multifidus muscle. We did not observe clear regional activation of lumbar muscle subregions in response to the vestibular stimuli. Our findings show that the central nervous system can finely tune the vestibular control of individual lumbar muscles and suggest minimal regional variations in the activation of lumbar muscle subregions.
Collapse
Affiliation(s)
- Alessio Gallina
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre of Precision Rehabilitation for Spinal Pain, School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jacques Abboud
- Département des Sciences de l'Activité Physique, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
- Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
7
|
Houben MMJ, Stuldreher IV, Forbes PA, Groen EL. Using Galvanic Vestibular Stimulation to Induce Post-Roll Illusion in a Fixed-Base Flight Simulator. Aerosp Med Hum Perform 2024; 95:84-92. [PMID: 38263100 DOI: 10.3357/amhp.6325.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
INTRODUCTION: The illusions of head motion induced by galvanic vestibular stimulation (GVS) can be used to compromise flight performance of pilots in fixed-base simulators. However, the stimuli used in the majority of studies fail to mimic disorientation in realistic flight because they are independent from the simulated aircraft motion. This study investigated the potential of bilateral-bipolar GVS coupled to aircraft roll in a fixed-base simulator to mimic vestibular spatial disorientation illusions, specifically the "post-roll illusion" observed during flight.METHODS: There were 14 nonpilot subjects exposed to roll stimuli in a flight simulator operating in a fixed-base mode. GVS was delivered via carbon rubber electrodes on the mastoid processes. The electrical stimulus was driven by the high-pass filtered aircraft roll rate to mimic the semicircular canals' physiological response. The post-roll test scenarios excluded outside visual cues or instruments and required subjects to actively maintain a constant bank angle after an abrupt stop following a passive prolonged roll maneuver. The anticipated outcome was an overshot in roll elicited by the GVS signal.RESULTS: The responses across subjects showed large variability, with less than a third aligning with the post-roll illusion. Subjective ratings suggest that the high-pass filtered GVS stimuli were mild and did not induce a clear sense of roll direction. However, uncontrolled head movements during stimulation might have obscured the intended effects of GVS-evoked illusory head movements.CONCLUSION: The mild and transient GVS stimuli used in this study, together with the uncontrolled head movements, did not convincingly mimic the post-roll illusion.Houben MMJ, Stuldreher IV, Forbes PA, Groen EL. Using galvanic vestibular stimulation to induce post-roll illusion in a fixed-base flight simulator. Aerosp Med Hum Perform. 2024; 95(2):84-92.
Collapse
|
8
|
Abstract
PURPOSE OF REVIEW Electrical stimulation of the peripheral and central vestibular system using noninvasive (galvanic vestibular stimulation, GVS) or invasive (intracranial electrical brain stimulation, iEBS) approaches have a long history of use in studying self-motion perception and balance control. The aim of this review is to summarize recent electrophysiological studies of the effects of GVS, and functional mapping of the central vestibular system using iEBS in awake patients. RECENT FINDINGS The use of GVS has become increasingly common in the assessment and treatment of a wide range of clinical disorders including vestibulopathy and Parkinson's disease. The results of recent single unit recording studies have provided new insight into the neural mechanisms underlying GVS-evoked improvements in perceptual and motor responses. Furthermore, the application of iEBS in patients with epilepsy or during awake brain surgery has provided causal evidence of vestibular information processing in mostly the middle cingulate cortex, posterior insula, inferior parietal lobule, amygdala, precuneus, and superior temporal gyrus. SUMMARY Recent studies have established that GVS evokes robust and parallel activation of both canal and otolith afferents that is significantly different from that evoked by natural head motion stimulation. Furthermore, there is evidence that GVS can induce beneficial neural plasticity in the central pathways of patients with vestibular loss. In addition, iEBS studies highlighted an underestimated contribution of areas in the medial part of the cerebral hemispheres to the cortical vestibular network.
Collapse
Affiliation(s)
- Christophe Lopez
- Aix Marseille Univ, CNRS, Laboratory of Cognitive Neuroscience (LNC), FR3C, Marseille, France
| | - Kathleen E. Cullen
- Department of Biomedical Engineering, Johns Hopkins University
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University
- Department of Neuroscience, Johns Hopkins University
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore 21205 MD, USA
| |
Collapse
|
9
|
Rasman BG, van der Zalm C, Forbes PA. Age-related impairments and influence of visual feedback when learning to stand with unexpected sensorimotor delays. Front Aging Neurosci 2023; 15:1325012. [PMID: 38161590 PMCID: PMC10757376 DOI: 10.3389/fnagi.2023.1325012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024] Open
Abstract
Background While standing upright, the brain must accurately accommodate for delays between sensory feedback and self-generated motor commands. Natural aging may limit adaptation to sensorimotor delays due to age-related decline in sensory acuity, neuromuscular capacity and cognitive function. This study examined balance learning in young and older adults as they stood with robot-induced sensorimotor delays. Methods A cohort of community dwelling young (mean = 23.6 years, N = 20) and older adults (mean = 70.1 years, N = 20) participated in this balance learning study. Participants stood on a robotic balance simulator which was used to artificially impose a 250 ms delay into their control of standing. Young and older adults practiced to balance with the imposed delay either with or without visual feedback (i.e., eyes open or closed), resulting in four training groups. We assessed their balance behavior and performance (i.e., variability in postural sway and ability to maintain upright posture) before, during and after training. We further evaluated whether training benefits gained in one visual condition transferred to the untrained condition. Results All participants, regardless of age or visual training condition, improved their balance performance through training to stand with the imposed delay. Compared to young adults, however, older adults had larger postural oscillations at all stages of the experiments, exhibited less relative learning to balance with the delay and had slower rates of balance improvement. Visual feedback was not required to learn to stand with the imposed delay, but it had a modest effect on the amount of time participants could remain upright. For all groups, balance improvements gained from training in one visual condition transferred to the untrained visual condition. Conclusion Our study reveals that while advanced age partially impairs balance learning, the older nervous system maintains the ability to recalibrate motor control to stand with initially destabilizing sensorimotor delays under differing visual feedback conditions.
Collapse
Affiliation(s)
- Brandon G. Rasman
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Christian van der Zalm
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Patrick A. Forbes
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- Department of Biomechanical Engineering, Delft University of Technology, Delft, Netherlands
| |
Collapse
|
10
|
Bzdúšková D, Marko M, Hirjaková Z, Riečanský I, Kimijanová J. Fear of heights shapes postural responses to vibration-induced balance perturbation at virtual height. Front Hum Neurosci 2023; 17:1229484. [PMID: 37771346 PMCID: PMC10523023 DOI: 10.3389/fnhum.2023.1229484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/21/2023] [Indexed: 09/30/2023] Open
Abstract
Introduction Standing upright at height is a challenging situation involving intense threat of balance loss and fall. The ability to maintain balance in such conditions requires properly resolving sensory conflicts and is influenced by fear. To get more insight on the role of fear in balance control at height, we explored the dynamics of postural behavior in the situation of enhanced threat of potential balance loss. Methods In 40 young individuals with varying fear of heights, we combined simulated exposure to height in a virtual reality environment with bilateral vibration of tibialis anterior muscles which evokes posture destabilization (the so-called vibration-induced falling). Results Under such condition of enhanced postural threat, individuals with intense fear of heights showed stronger stiffening of posture compared with individuals with low fear of heights who react more flexibly and adaptively to posture destabilization. This group difference was evident already at ground level but further increased during virtual height exposure. Discussion Our data show that fear of height significantly affects posture adaptation to balance-destabilizing events. Our findings demonstrate that the assessment of postural behavior during threatening situations in the virtual reality environment provides valuable insights into the mechanisms of balance control and may be used to develop novel strategies aimed at prevention of falls.
Collapse
Affiliation(s)
- Diana Bzdúšková
- Department of Behavioural Neuroscience, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Martin Marko
- Department of Behavioural Neuroscience, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
- Department of Applied Informatics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Bratislava, Slovakia
| | - Zuzana Hirjaková
- Department of Behavioural Neuroscience, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Igor Riečanský
- Department of Behavioural Neuroscience, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
- Department of Psychiatry, Faculty of Medicine, Slovak Medical University in Bratislava, Bratislava, Slovakia
| | - Jana Kimijanová
- Department of Behavioural Neuroscience, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| |
Collapse
|
11
|
Forbes PA, Kwan A, Mitchell DE, Blouin JS, Cullen KE. The Neural Basis for Biased Behavioral Responses Evoked by Galvanic Vestibular Stimulation in Primates. J Neurosci 2023; 43:1905-1919. [PMID: 36732070 PMCID: PMC10027042 DOI: 10.1523/jneurosci.0987-22.2023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
Noninvasive electrical stimulation of the vestibular system in humans has become an increasingly popular tool with a broad range of research and clinical applications. However, common assumptions regarding the neural mechanisms that underlie the activation of central vestibular pathways through such stimulation, known as galvanic vestibular stimulation (GVS), have not been directly tested. Here, we show that GVS is encoded by VIIIth nerve vestibular afferents with nonlinear dynamics that differ markedly from those predicted by current models. GVS produced asymmetric activation of both semicircular canal and otolith afferents to the onset versus offset and cathode versus anode of applied current, that in turn produced asymmetric eye movement responses in three awake-behaving male monkeys. Additionally, using computational methods, we demonstrate that the experimentally observed nonlinear neural response dynamics lead to an unexpected directional bias in the net population response when the information from both vestibular nerves is centrally integrated. Together our findings reveal the neural basis by which GVS activates the vestibular system, establish that neural response dynamics differ markedly from current predictions, and advance our mechanistic understanding of how asymmetric activation of the peripheral vestibular system alters vestibular function. We suggest that such nonlinear encoding is a general feature of neural processing that will be common across different noninvasive electrical stimulation approaches.SIGNIFICANCE STATEMENT Here, we show that the application of noninvasive electrical currents to the vestibular system (GVS) induces more complex responses than commonly assumed. We recorded vestibular afferent activity in macaque monkeys exposed to GVS using a setup analogous to human studies. GVS evoked notable asymmetries in irregular afferent responses to cathodal versus anodal currents. We developed a nonlinear model explaining these GVS-evoked afferent responses. Our model predicts that GVS induces directional biases in centrally integrated head motion signals and establishes electrical stimuli that recreate physiologically plausible sensations of motion. Altogether, our findings provide new insights into how GVS activates the vestibular system, which will be vital to advancing new clinical and biomedical applications.
Collapse
Affiliation(s)
- Patrick A Forbes
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands
| | | | | | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, British Colombia V6T 1Z1, Canada
| | - Kathleen E Cullen
- Physiology, McGill University, Montréal, Québec H3G 1Y6, Canada
- Departments of Biomedical Engineering
- Otolaryngology-Head and Neck Surgery
- Neuroscience, Johns Hopkins University, Baltimore, Maryland 21205
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, Maryland 21205
| |
Collapse
|
12
|
Choi JY, Koo YJ, Song JM, Kim HJ, Kim JS. Effect of a False Inertial Cue in the Velocity-Storage Circuit on Head Posture and Inertia Perception. J Neurosci 2023; 43:1530-1539. [PMID: 36669887 PMCID: PMC10008054 DOI: 10.1523/jneurosci.1148-22.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 12/16/2022] [Accepted: 01/08/2023] [Indexed: 01/22/2023] Open
Abstract
The velocity-storage circuit participates in the vestibulopostural reflex, but its role in the postural reflex requires further elucidation. The velocity-storage circuit differentiates gravitoinertial information into gravitational and inertial cues using rotational cues. This implies that a false rotational cue can cause an erroneous estimation of gravity and inertial cues. We hypothesized the velocity-storage circuit is a common gateway for all vestibular reflex pathways and tested that hypothesis by measuring the postural and perceptual responses from a false inertial cue estimated in the velocity-storage circuit. Twenty healthy human participants (40.5 ± 8.2 years old, 6 men) underwent two different sessions of earth-vertical axis rotations at 120°/s for 60 s. During each session, the participants were rotated clockwise and then counterclockwise with two different starting head positions (head-down and head-up). During the first (control) session, the participants kept a steady head position at the end of rotation. During the second (test) session, the participants changed their head position at the end of rotation, from head-down to head-up or vice versa. The head position and inertial motion perception at the end of rotation were aligned with the inertia direction anticipated by the velocity-storage model. The participants showed a significant correlation between postural and perceptual responses. The velocity-storage circuit appears to be a shared neural integrator for the vestibulopostural reflex and vestibular perception. Because the postural responses depended on the inertial direction, the postural instability in vestibular disorders may be the consequence of the vestibulopostural reflex responding to centrally estimated false vestibular cues.SIGNIFICANCE STATEMENT The velocity-storage circuit appears to participate in the vestibulopostural reflex, which stabilizes the head and body position in space. However, it is still unclear whether the velocity-storage circuit for the postural reflex is in common with that involved in eye movement and perception. We evaluated the postural and perceptual responses to a false inertial cue estimated by the velocity-storage circuit. The postural and perceptual responses were consistent with the inertia direction predicted in the velocity-storage model and were correlated closely with each other. These results show that the velocity-storage circuit is a shared neural integrator for vestibular-driven responses and suggest that the vestibulopostural response to a false vestibular cue is the pathomechanism of postural instability clinically observed in vestibular disorders.
Collapse
Affiliation(s)
- Jeong-Yoon Choi
- Dizziness Center, Clinical Neuroscience Center, and Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi 13620 South Korea
- Department of Neurology, Seoul National University College of Medicine, Seoul 03080, South Korea
| | - Yu Jin Koo
- Dizziness Center, Clinical Neuroscience Center, and Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi 13620 South Korea
| | - Jung-Mi Song
- Dizziness Center, Clinical Neuroscience Center, and Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi 13620 South Korea
| | - Hyo-Jung Kim
- Research Administration Team, Seoul National University Bundang Hospital, Seongnam, Gyeonggi 13620 South Korea
| | - Ji-Soo Kim
- Dizziness Center, Clinical Neuroscience Center, and Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi 13620 South Korea
- Department of Neurology, Seoul National University College of Medicine, Seoul 03080, South Korea
| |
Collapse
|
13
|
Han Y, Bai Y, Liu Q, Zhao Y, Chen T, Wang W, Ni G. Assessing vestibular function using electroencephalogram rhythms evoked during the caloric test. Front Neurol 2023; 14:1126214. [PMID: 36908620 PMCID: PMC9996014 DOI: 10.3389/fneur.2023.1126214] [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: 12/17/2022] [Accepted: 01/31/2023] [Indexed: 02/25/2023] Open
Abstract
Introduction The vestibular system is responsible for motion perception and balance preservation in the body. The vestibular function examination is useful for determining the cause of associated symptoms, diagnosis, and therapy of the patients. The associated cerebral cortex processes and integrates information and is the ultimate perceptual site for vestibular-related symptoms. In recent clinical examinations, less consideration has been given to the cortex associated with the vestibular system. As a result, it is crucial to increase focus on the expression of the cortical level while evaluating vestibular function. From the viewpoint of neuroelectrophysiology, electroencephalograms (EEG) can enhance the assessments of vestibular function at the cortex level. Methods This study recorded nystagmus and EEG data throughout the caloric test. Four phases were considered according to the vestibular activation status: before activation, activation, fixation suppression, and recovery. In different phases, the distribution and changes of the relative power of the EEG rhythms (delta, theta, alpha, and beta) were analyzed, and the correlation between EEG characteristics and nystagmus was also investigated. Results The results showed that, when the vestibule was activated, the alpha power of the occipital region increased, and the beta power of the central and top regions and the occipital region on the left decreased. The changes in the alpha and beta rhythms significantly correlate with nystagmus values in left warm stimulation. Discussion Our findings offer a fresh perspective on cortical electrophysiology for the assessment of vestibular function by demonstrating that the relative power change in EEG rhythms can be used to assess vestibular function.
Collapse
Affiliation(s)
- Yutong Han
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China.,Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin, China
| | - Yanru Bai
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China.,Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin, China
| | - Qiang Liu
- Key Laboratory of Auditory Speech and Balance Medicine, Tianjin, China.,Institute of Otolaryngology of Tianjin, Tianjin, China.,Key Medical Discipline of Tianjin (Otolaryngology), Tianjin, China
| | - Yuncheng Zhao
- Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin, China.,Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China
| | - Taisheng Chen
- Key Laboratory of Auditory Speech and Balance Medicine, Tianjin, China.,Institute of Otolaryngology of Tianjin, Tianjin, China.,Key Medical Discipline of Tianjin (Otolaryngology), Tianjin, China
| | - Wei Wang
- Key Laboratory of Auditory Speech and Balance Medicine, Tianjin, China.,Institute of Otolaryngology of Tianjin, Tianjin, China.,Key Medical Discipline of Tianjin (Otolaryngology), Tianjin, China
| | - Guangjian Ni
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China.,Tianjin Key Laboratory of Brain Science and Neuroengineering, Tianjin, China
| |
Collapse
|
14
|
Debenham MIB, Kang HJ, Cheung SS, Dalton BH. The influence of reduced foot dorsum cutaneous sensitivity on the vestibular control of balance. Eur J Appl Physiol 2023; 123:65-79. [PMID: 36169737 DOI: 10.1007/s00421-022-05043-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 09/03/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE Foot sole cooling increases vestibular-evoked balance responses, but less is known about foot dorsum temperature alterations. The purpose was to determine whether decreasing cutaneous receptor sensitivity via foot dorsum cooling modulates the vestibular control of balance. METHODS Eighteen participants (9 males; 9 females) stood quietly on a force plate with feet together, eyes closed, and head rotated leftward during 4, 90-s trials (2 control; 2 cooled) of continuous electrical vestibular stimulation (EVS). Icepacks placed on the dorsum of both feet for 15 min induced cooling and remained throughout the EVS trials. Monofilament testing was performed at multiple locations before and after cooling to determine tactile detection thresholds. T-type thermocouples monitored skin temperature over the tibialis anterior, soleus, foot dorsum and arch of the right leg. Vestibular-evoked balance responses were characterized using time (cumulant density) and frequency (coherence and gain) domain analyses to determine the relationship between the EVS input and motor output (anteroposterior force-AP force; right medial gastrocnemius electromyography-MG EMG). RESULTS Skin temperature of the foot dorsum and arch decreased ~ 70 and 15%, respectively during cooling (p < 0.05), but was unaltered at other locations (p ≥ 0.10). Detection thresholds for the foot dorsum increased following cooling (p < 0.05). Surprisingly, cooling reduced EVS-AP force and EVS-MG EMG coherence and gain at multiple frequencies, and peak-to-peak amplitude compared to control (p < 0.05). CONCLUSION Our results indicate that vestibular-driven balance responses are reduced following foot dorsum cooling, likely owing to alterations in cutaneous mechanoreceptor sensitivity and subsequent alterations in the transformation of vestibular cues for balance control.
Collapse
Affiliation(s)
- Mathew I B Debenham
- Sensorimotor Physiology and Integrative Neuromechanics Lab, Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Hogun J Kang
- Sensorimotor Physiology and Integrative Neuromechanics Lab, Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Stephen S Cheung
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - Brian H Dalton
- Sensorimotor Physiology and Integrative Neuromechanics Lab, Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada.
| |
Collapse
|
15
|
Cullen KE. Vestibular motor control. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:31-54. [PMID: 37562876 DOI: 10.1016/b978-0-323-98818-6.00022-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The vestibular system is an essential sensory system that generates motor reflexes that are crucial for our daily activities, including stabilizing the visual axis of gaze and maintaining head and body posture. In addition, the vestibular system provides us with our sense of movement and orientation relative to space and serves a vital role in ensuring accurate voluntary behaviors. Neurophysiological studies have provided fundamental insights into the functional circuitry of vestibular motor pathways. A unique feature of the vestibular system compared to other sensory systems is that the same central neurons that receive direct input from the afferents of the vestibular component of the 8th nerve can also directly project to motor centers that control vital vestibular motor reflexes. In turn, these reflexes ensure stabilize gaze and the maintenance of posture during everyday activities. For instance, a direct three-neuron pathway mediates the vestibulo-ocular reflex (VOR) pathway to provide stable gaze. Furthermore, recent studies have advanced our understanding of the computations performed by the cerebellum and cortex required for motor learning, compensation, and voluntary movement and navigation. Together, these findings have provided new insights into how the brain ensures accurate self-movement during our everyday activities and have also advanced our knowledge of the neurobiological mechanisms underlying disorders of vestibular processing.
Collapse
Affiliation(s)
- Kathleen E Cullen
- Departments of Biomedical Engineering, of Otolaryngology-Head and Neck Surgery, and of Neuroscience; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States.
| |
Collapse
|
16
|
Effects of vestibular stimulation on gait stability when walking at different step widths. Exp Brain Res 2023; 241:49-58. [PMID: 36346447 DOI: 10.1007/s00221-022-06488-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 10/03/2022] [Indexed: 11/11/2022]
Abstract
Vestibular information modulates muscle activity during gait, presumably to contribute to stability. If this is the case, stronger effects of perturbing vestibular information on local dynamic stability of gait, a measure of the locomotor system's response to small, naturally occurring perturbations, can be expected for narrow-base walking (which needs more control) than for normal walking and smaller effects for wide-base walking (which needs less control). An important mechanism to stabilize gait is to coordinate foot placement to center of mass (CoM) state. Vestibular information most likely contributes to sensing this CoM state. We, therefore, expected that stochastic electrical vestibular stimulation (EVS) would decrease the correlation between foot placement and CoM state during the preceding swing phase. In 14 healthy participants, we measured the kinematics of the trunk (as a proxy of the CoM), and feet, while they walked on a treadmill in six conditions: control (usual step width), narrow-base, and wide-base, each with and without stochastic EVS (peak amplitude of 5 mA; RMS of ~ 1.2 mA; frequency band from 0 to 25 Hz). Stochastic EVS decreased local dynamic stability irrespective of step width. Foot placement correlated stronger with trunk motion during walking with EVS than without in the control condition. However, residual variance in foot placement was increased when walking with EVS, indicating less precise foot placement. Thus, a vestibular error signal leads to a decrease in gait stability and precision of foot placement, but these effects are not consistently modulated by step width.
Collapse
|
17
|
Tisserand R, Rasman BG, Omerovic N, Peters RM, Forbes PA, Blouin JS. Unperceived motor actions of the balance system interfere with the causal attribution of self-motion. PNAS NEXUS 2022; 1:pgac174. [PMID: 36714829 PMCID: PMC9802180 DOI: 10.1093/pnasnexus/pgac174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 08/25/2022] [Indexed: 02/01/2023]
Abstract
The instability of human bipedalism demands that the brain accurately senses balancing self-motion and determines whether movements originate from self-generated actions or external disturbances. Here, we challenge the longstanding notion that this process relies on a single representation of the body and world to accurately perceive postural orientation and organize motor responses to control balance self-motion. Instead, we find that the conscious sense of balance can be distorted by the corrective control of upright standing. Using psychophysics, we quantified thresholds to imposed perturbations and balance responses evoking cues of self-motion that are (in)distinguishable from corrective balance actions. When standing immobile, participants clearly perceived imposed perturbations. Conversely, when freely balancing, participants often misattributed their own corrective responses as imposed motion because their balance system had detected, integrated, and responded to the perturbation in the absence of conscious perception. Importantly, this only occurred for perturbations encoded ambiguously with balance-correcting responses and that remained below the natural variability of ongoing balancing oscillations. These findings reveal that our balance system operates on its own sensorimotor principles that can interfere with causal attribution of our actions, and that our conscious sense of balance depends critically on the source and statistics of induced and self-generated motion cues.
Collapse
Affiliation(s)
- Romain Tisserand
- School of Kinesiology, University of British Columbia, Vancouver, BC V6T 1Z1, Canada,Institut PPRIME (UPR3346), Université de Poitiers ENSMA, CNRS, 86360 Chasseneuil-du-Poitou, France,Centre de Recherches sur la Cognition et l'Apprentissage (UMR 7295), Université de Poitiers, Université de Tours, CNRS, 86073 Poitiers, France
| | - Brandon G Rasman
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam 3015 GD, The Netherlands,School of Physical Education, Sport, and Exercise Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Nina Omerovic
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam 3015 GD, The Netherlands
| | - Ryan M Peters
- School of Kinesiology, University of British Columbia, Vancouver, BC V6T 1Z1, Canada,Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | | | | |
Collapse
|
18
|
Pryhoda M, Newell KM, Wilson C, Irwin G. Task Specific and General Patterns of Joint Motion Variability in Upright- and Hand-Standing Postures. ENTROPY 2022; 24:e24070909. [PMID: 35885134 PMCID: PMC9323647 DOI: 10.3390/e24070909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/05/2022] [Accepted: 06/23/2022] [Indexed: 12/17/2022]
Abstract
The preservation of static balance in both upright- and hand-stance is maintained by the projection of center of mass (CM) motion within the region of stability at the respective base of support. This study investigated, from a degrees of freedom (DF) perspective, whether the stability of the CM in both upright- and hand-stances was predicted by the respective dispersion and time-dependent regularity of joint (upright stance—ankle, knee, hip, shoulder, neck; hand stance—wrist, elbow, shoulder, neck) angle and position. Full body three-dimensional (3D) kinematic data were collected on 10 advanced level junior female gymnasts during 30 s floor upright- and hand-stands. For both stances the amount of the dispersion of joint angle and sway motion was higher than that of the CM and center of pressure (CP) with an inverse relation to time-dependent irregularity (SampEn). In upright-standing the variability of neck motion in the anterior–posterior direction was significantly greater than that of most joints consistent with the role of vision in the control of quiet upright posture. The findings support the proposition that there are both task specific and general properties to the global CM control strategy in the balance of upright- and hand-standing induced by the different active skeletal-muscular organization and the degeneracy revealed in the multiple distributional variability patterns of the joint angle and position in 3D.
Collapse
Affiliation(s)
- Moira Pryhoda
- Department of Mechanical and Materials Engineering, University of Denver, Denver, CO 80208, USA
| | - Karl M Newell
- Department of Kinesiology, University of Georgia, Athens, GA 30602, USA
| | - Cassie Wilson
- Department for Health, University of Bath, Bath BA2 7AY, UK
| | - Gareth Irwin
- Cardiff School of Sport and Health Science, Cardiff Metropolitan University, Cardiff CF23 6XD, UK
| |
Collapse
|
19
|
García-Muñoz C, Cortés-Vega MD, Hernández-Rodríguez JC, Fernández-Seguín LM, Escobio-Prieto I, Casuso-Holgado MJ. Immersive Virtual Reality and Vestibular Rehabilitation in Multiple Sclerosis: Case Report. JMIR Serious Games 2021; 10:e31020. [PMID: 34766551 PMCID: PMC8892276 DOI: 10.2196/31020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/07/2021] [Accepted: 10/12/2021] [Indexed: 02/06/2023] Open
Abstract
Background Dizziness and imbalance are common and disabling symptoms in patients with multiple sclerosis (MS) and are caused by a central, peripheral, or mixed vestibulopathy. Central vestibular disorder is the most frequently reported vestibular problem in the MS population due to demyelination. Vestibular rehabilitation ameliorates these symptoms and their repercussions and improves quality of life. Immersive virtual reality (VRi) is an emerging tool in this field; however, no previous research has been performed studying its effects in MS. Objective The aim of this study was to apply a VRi vestibular training protocol to a patient with MS and assess the effects induced by the experimental intervention. Methods This case study included a 54-year-old woman with relapsing-remitting MS. We developed a standardized VRi exercise protocol for vestibular rehabilitation based on the gold-standard Cawthorne-Cooksey vestibular training protocol. The 20-session intervention was made up of 10 initial sessions and 10 advanced sessions. Each 50-minute session was performed two to three times per week for 7 weeks. Four evaluations were carried out over the study period: at baseline (T0), between initial and advances phases (T1), postintervention (T2), and 1 month after the experimental procedure (T3). The research outcomes were dizziness, balance, gait, impact of fatigue, quality of life, repercussions in muscular tone, and usability of the head-mounted display device. Results After implementing the VRi vestibular protocol, improvements were seen in the following patient parameters: Dizziness Handicap Inventory score (62 points at T0; 4 points at T2); Berg Balance Scale score (47 points at T0; 54 points at T2); instrumented Timed Up and Go time (8.35 seconds at T0; 5.57 seconds at T2); muscular tone of the erector spinae, rectus femoris, and soleus; Modified Fatigue Impact Scale score (61 points at T0; 37 points at T2); and Multiple Sclerosis Quality of Life-54 values (67.16% in the physical health area at T2; 33.56% in the mental health area at T2). The patient rated the usability of the system as 90%, based on the System Usability Scale, and gave the system a grade of A. Conclusions Although further research is needed, this study provided initial evidence that the first VRi vestibular protocol for the MS population can improve dizziness, balance, gait, impact of fatigue, quality of life, and muscular tone through an exergame intervention. This study may help establish a standardized VRi protocol for vestibular rehabilitation.
Collapse
Affiliation(s)
- Cristina García-Muñoz
- Physiotherapy Department. Faculty of Nursing, Physiotherapy and Podiatry., University of Seville, C/ Avicena S/N, Seville, ES
| | - María-Dolores Cortés-Vega
- Physiotherapy Department. Faculty of Nursing, Physiotherapy and Podiatry., University of Seville, C/ Avicena S/N, Seville, ES
| | | | - Lourdes M Fernández-Seguín
- Physiotherapy Department. Faculty of Nursing, Physiotherapy and Podiatry., University of Seville, C/ Avicena S/N, Seville, ES
| | - Isabel Escobio-Prieto
- Physiotherapy Department. Faculty of Nursing, Physiotherapy and Podiatry., University of Seville, C/ Avicena S/N, Seville, ES
| | - María Jesús Casuso-Holgado
- Physiotherapy Department. Faculty of Nursing, Physiotherapy and Podiatry., University of Seville, C/ Avicena S/N, Seville, ES
| |
Collapse
|
20
|
Potential Mechanisms of Acute Standing Balance Deficits After Concussions and Subconcussive Head Impacts: A Review. Ann Biomed Eng 2021; 49:2693-2715. [PMID: 34258718 DOI: 10.1007/s10439-021-02831-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/29/2021] [Indexed: 01/04/2023]
Abstract
Standing balance deficits are prevalent after concussions and have also been reported after subconcussive head impacts. However, the mechanisms underlying such deficits are not fully understood. The objective of this review is to consolidate evidence linking head impact biomechanics to standing balance deficits. Mechanical energy transferred to the head during impacts may deform neural and sensory components involved in the control of standing balance. From our review of acute balance-related changes, concussions frequently resulted in increased magnitude but reduced complexity of postural sway, while subconcussive studies showed inconsistent outcomes. Although vestibular and visual symptoms are common, potential injury to these sensors and their neural pathways are often neglected in biomechanics analyses. While current evidence implies a link between tissue deformations in deep brain regions including the brainstem and common post-concussion balance-related deficits, this link has not been adequately investigated. Key limitations in current studies include inadequate balance sampling duration, varying test time points, and lack of head impact biomechanics measurements. Future investigations should also employ targeted quantitative methods to probe the sensorimotor and neural components underlying balance control. A deeper understanding of the specific injury mechanisms will inform diagnosis and management of balance deficits after concussions and subconcussive head impact exposure.
Collapse
|
21
|
Rasman BG, Forbes PA, Peters RM, Ortiz O, Franks I, Inglis JT, Chua R, Blouin JS. Learning to stand with unexpected sensorimotor delays. eLife 2021; 10:65085. [PMID: 34374648 PMCID: PMC8480973 DOI: 10.7554/elife.65085] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 08/04/2021] [Indexed: 11/23/2022] Open
Abstract
Human standing balance relies on self-motion estimates that are used by the nervous system to detect unexpected movements and enable corrective responses and adaptations in control. These estimates must accommodate for inherent delays in sensory and motor pathways. Here, we used a robotic system to simulate human standing about the ankles in the anteroposterior direction and impose sensorimotor delays into the control of balance. Imposed delays destabilized standing, but through training, participants adapted and re-learned to balance with the delays. Before training, imposed delays attenuated vestibular contributions to balance and triggered perceptions of unexpected standing motion, suggesting increased uncertainty in the internal self-motion estimates. After training, vestibular contributions partially returned to baseline levels and larger delays were needed to evoke perceptions of unexpected standing motion. Through learning, the nervous system accommodates balance sensorimotor delays by causally linking whole-body sensory feedback (initially interpreted as imposed motion) to self-generated balance motor commands. When standing, neurons in the brain send signals to skeletal muscles so we can adjust our movements to stay upright based on the requirements from the surrounding environment. The long nerves needed to connect our brain, muscles and sensors lead to considerable time delays (up to 160 milliseconds) between sensing the environment and the generation of balance-correcting motor signals. Such delays must be accounted for by the brain so it can adjust how it regulates balance and compensates for unexpected movements. Aging and neurological disorders can lead to lengthened neural delays, which may result in poorer balance. Computer modeling suggests that we cannot maintain upright balance if delays are longer than 300-340 milliseconds. Directly assessing the destabilizing effects of increased delays in human volunteers can reveal how capable the brain is at adapting to this neurological change. Using a custom-designed robotic balance simulator, Rasman et al. tested whether healthy volunteers could learn to balance with delays longer than the predicted 300-340 millisecond limit. In a series of experiments, 46 healthy participants stood on the balance simulator which recreates the physical sensations and neural signals for balancing upright based on a computer-driven virtual reality. This unique device enabled Rasman et al. to artificially impose delays by increasing the time between the generation of motor signals and resulting whole-body motion. The experiments showed that lengthening the delay between motor signals and whole-body motion destabilized upright standing, decreased sensory contributions to balance and led to perceptions of unexpected movements. Over five days of training on the robotic balance simulator, participants regained their ability to balance, which was accompanied by recovered sensory contributions and perceptions of expected standing, despite the imposed delays. When a subset of participants was tested three months later, they were still able to compensate for the increased delay. The experiments show that the human brain can learn to overcome delays up to 560 milliseconds in the control of balance. This discovery may have important implications for people who develop balance problems because of older age or neurologic diseases like multiple sclerosis. It is possible that robot-assisted training therapies, like the one in this study, could help people overcome their balance impairments.
Collapse
Affiliation(s)
- Brandon G Rasman
- School of Physical Education, Sport, and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Patrick A Forbes
- Department of Neuroscience, Erasmus University Medical Centre, Rotterdam, Netherlands
| | - Ryan M Peters
- Faculty of Kinesiology, University of Calgary, Calgary, Canada
| | - Oscar Ortiz
- Faculty of Kinesiology, University of New Brunswick, Fredericton, Canada
| | - Ian Franks
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - J Timothy Inglis
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Romeo Chua
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | | |
Collapse
|
22
|
Magnani RM, Bruijn SM, van Dieën JH, Forbes PA. Stabilization demands of walking modulate the vestibular contributions to gait. Sci Rep 2021; 11:13736. [PMID: 34215780 PMCID: PMC8253745 DOI: 10.1038/s41598-021-93037-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 06/04/2021] [Indexed: 12/26/2022] Open
Abstract
Stable walking relies critically on motor responses to signals of head motion provided by the vestibular system, which are phase-dependent and modulated differently within each muscle. It is unclear, however, whether these vestibular contributions also vary according to the stability of the walking task. Here we investigate how vestibular signals influence muscles relevant for gait stability (medial gastrocnemius, gluteus medius and erector spinae)-as well as their net effect on ground reaction forces-while humans walked normally, with mediolateral stabilization, wide and narrow steps. We estimated local dynamic stability of trunk kinematics together with coherence of electrical vestibular stimulation (EVS) with muscle activity and mediolateral ground reaction forces. Walking with external stabilization increased local dynamic stability and decreased coherence between EVS and all muscles/forces compared to normal walking. Wide-base walking also decreased vestibulomotor coherence, though local dynamic stability did not differ. Conversely, narrow-base walking increased local dynamic stability, but produced muscle-specific increases and decreases in coherence that resulted in a net increase in vestibulomotor coherence with ground reaction forces. Overall, our results show that while vestibular contributions may vary with gait stability, they more critically depend on the stabilization demands (i.e. control effort) needed to maintain a stable walking pattern.
Collapse
Affiliation(s)
- Rina M Magnani
- Department of Physiotherapy, School of Physical Education and Physical Therapy, State University of Goiás, Goiânia, GO, Brazil
| | - Sjoerd M Bruijn
- Department of Human Movement Sciences, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands.,Institute Brain and Behavior Amsterdam, Amsterdam, The Netherlands
| | - Jaap H van Dieën
- Department of Human Movement Sciences, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Patrick A Forbes
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands.
| |
Collapse
|
23
|
Guillaud E, Seyres P, Barrière G, Jecko V, Bertrand SS, Cazalets JR. Locomotion and dynamic posture: neuro-evolutionary basis of bipedal gait. Neurophysiol Clin 2020; 50:467-477. [PMID: 33176989 DOI: 10.1016/j.neucli.2020.10.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/23/2020] [Accepted: 10/23/2020] [Indexed: 12/24/2022] Open
Abstract
Body displacement during locomotion is a major challenge for motor control, requiring complex synergistic postural regulation and the integrated functioning of all body musculature, including that of the four limbs, trunk and neck. Despite the obvious pivotal role played by the trunk during locomotion, most studies devoted to understanding the neural basis of locomotor control have only addressed the operation of the neural circuits driving leg movements, and relatively little is known of the networks that control trunk muscles in limbed vertebrates. This review addresses this issue, both in animals and humans. We first review studies addressing the central role played by central pattern generator (CPG) circuit interactions within the spinal cord in coordinating trunk and hind limb muscle activities in a variety of vertebrates, and present evidence that vestibulo-spinal reflexes are differentially involved in trunk and hind limb control. We finally highlight the role of the various components that participate in maintaining dynamic equilibrium during stepping, including connective tissues. We propose that many aspects of the organization of the motor systems involved in trunk-hind limb movement control in vertebrates have been highly conserved throughout evolution.
Collapse
Affiliation(s)
- Etienne Guillaud
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Philippe Seyres
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Gregory Barrière
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Vincent Jecko
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Sandrine S Bertrand
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France
| | - Jean-René Cazalets
- Université de Bordeaux, CNRS UMR 5287, INCIA, Zone nord, Bat 2, 2e étage, 146 rue Léo Saignat, 33076 Bordeaux cedex, France.
| |
Collapse
|
24
|
Feldman AG, Zhang L. Eye and head movements and vestibulo-ocular reflex in the context of indirect, referent control of motor actions. J Neurophysiol 2020; 124:115-133. [PMID: 32490708 PMCID: PMC7474454 DOI: 10.1152/jn.00076.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/06/2020] [Accepted: 05/23/2020] [Indexed: 01/03/2023] Open
Abstract
Conventional explanations of the vestibulo-ocular reflex (VOR) and eye and head movements are revisited by considering two alternative frameworks addressing the question of how the brain controls motor actions. Traditionally, biomechanical and/or computational frameworks reflect the views of several prominent scholars of the past, including Helmholtz and von Holst, who assumed that the brain directly specifies the desired motor outcome and uses efference copy to influence perception. However, empirical studies resulting in the theory of referent control of action and perception (an extension of the equilibrium-point hypothesis) revealed that direct specification of motor outcome is inconsistent with nonlinear properties of motoneurons and with the physical principle that the brain can control motor actions only indirectly, by changing or maintaining the values of neurophysiological parameters that influence, but can remain independent of, biomechanical variables. Some parameters are used to shift the origin (referent) points of spatial frames of reference (FRs) or system of coordinates in which motor actions emerge without being predetermined. Parameters are adjusted until the emergent motor actions meet the task demands. Several physiological parameters and spatial FRs have been identified, supporting the notion of indirect, referent control of movements. Instead of integration of velocity-dependent signals, position-dimensional referent signals underlying head motion can likely be transmitted to motoneurons of extraocular muscles. This would produce compensatory eye movement preventing shifts in gaze during head rotation, even after bilateral destruction of the labyrinths. The referent control framework symbolizes a shift in the paradigm for the understanding of VOR and eye and head movement production.
Collapse
Affiliation(s)
- Anatol G Feldman
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
| | - Lei Zhang
- Institut für Neuroinformatik, Ruhr-Universität Bochum, Bochum, Germany
| |
Collapse
|
25
|
Impact of visual signals on axial segmental control during walking in patients with vestibular disorder and healthy persons. J Biomech 2020; 104:109712. [PMID: 32164963 DOI: 10.1016/j.jbiomech.2020.109712] [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: 08/02/2019] [Revised: 01/17/2020] [Accepted: 02/18/2020] [Indexed: 11/21/2022]
Abstract
Head and trunk control during standing in patients with vestibular disorder may depend on intact visual signal to override vestibular disturbance. It is unknown if such process during walking would change. Therefore, the aims of this study were to quantify (1) head and trunk control in healthy participants (HPs) and patients with unilateral vestibular hypofunction (UVH) during walking with and without visual manipulation; and (2) the correlation/association between vestibular function and head/trunk control during walking with visual manipulation in patients. Seventeen UVH patients and 15 HPs completed all the tests. They participated in the caloric test, which was used to examine vestibular function, and walked on a treadmill with and without visual manipulation. Head and trunk angular displacement and velocity were primary outcome measures, deviation of center of mass and step variability were secondary. Head roll angular displacement (7.38° ± 1.38 [mean ± SE] v.s. 12.95° ± 1.48, p = 0.004) and head-trunk correlation (in the pitch/sagittal plane: 0.22 ± 0.05 v.s. 0.38 ± 0.05, roll/frontal plane: 0.35 ± 0.06 v.s. 0.55 ± 0.06, p < 0.05) were significantly lower in patients compared to HPs. Head pitch angular velocity (8.58°/s ± 2.17 v.s. 14.23°/s ± 1.22, p = 0.026) and step width variability (0.075 ± 0.010 v.s. 0.083 ± 0.009, p = 0.04) increased with visual manipulation only in patients. No significant correlation/association was found between vestibular function and head/trunk control. Lower head-trunk correlation in patients suggests an independent head-trunk control strategy in response to vestibular impairment. Visual input could be used by patients to compensate for vestibular disturbance for head control and foot placement. Severe UVH may not lead to worse postural control compared to mild disorder.
Collapse
|
26
|
Ha SY, Sung YH. A temporary forward head posture decreases function of cervical proprioception. J Exerc Rehabil 2020; 16:168-174. [PMID: 32509702 PMCID: PMC7248444 DOI: 10.12965/jer.2040106.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/27/2020] [Indexed: 12/19/2022] Open
Abstract
Increased use of smartphones can cause abnormal alignment of head and neck, resulting in forward head posture (FHP). This can lead to change in the structures and function of the cervical vertebrae. The purpose of this study was to determine the impact on deep neck flexor muscles, proprioception, vestibular function, and balance of subjects with induced FHP by using smartphone. Twenty-two healthy persons were randomly divided into two groups. The FHP group maintained a craniovertebral angle (CVA) of <49° and a normal head posture group maintained a CVA of >50° watching the smartphone for 40 min. We measured the area of the longus colli and longus capitis muscles, cervical joint position sense, Romberg test, subjective visual vertical test, and subjective visual horizontal test. There was no significant difference in the deep neck flexor muscles, vestibular function, and static balance between the groups. However, there was a significant difference in the cervical proprioception (P<0.05). Proprioception may be considered to be the most influential factor in induced FHP by smartphone viewing.
Collapse
Affiliation(s)
- Sun-Young Ha
- Department of Physical Therapy, Graduate School, Kyungnam University, Changwon, Korea
| | - Yun-Hee Sung
- Department of Physical Therapy, Graduate School, Kyungnam University, Changwon, Korea.,Department of Physical Therapy, College of Health Sciences, Kyungnam University, Changwon, Korea
| |
Collapse
|
27
|
Guillaud E, Faure C, Doat E, Bouyer LJ, Guehl D, Cazalets JR. Ancestral persistence of vestibulospinal reflexes in axial muscles in humans. J Neurophysiol 2020; 123:2010-2023. [PMID: 32319843 DOI: 10.1152/jn.00421.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Most studies addressing the role of vestibulospinal reflexes in balance maintenance have mainly focused on responses in the lower limbs, while limited attention has been paid to the output in trunk and back muscles. To address this issue, we tested whether electromyographic (EMG) responses to galvanic vestibular stimulations (GVS) were modulated similarly in back and leg muscles, in situations where the leg muscle responses to GVS are known to be attenuated. Body sway and surface EMG signals were recorded in the paraspinal and limb muscles of humans (n = 19) under three complementary conditions. During treadmill locomotion, EMG responses in the lower limbs were observed only during stance, whereas responses in trunk muscles were observed during all phases of the locomotor cycle. During upright standing, a slight head contact abolished the responses in the lower limbs, while the responses remained present in back muscles. Similarly, during parabolic flight-induced microgravity, EMG responses in lower limb muscles were suppressed but remained in axial muscles despite the abolished gravitational otolithic drive. Our results suggest a differentiated control of axial and appendicular muscles when a perturbation is detected by vestibular inputs. The persistence and low modulation of axial muscle responses suggests that a hard-wired reflex is functionally efficient to maintain posture. By contrast, the ankle responses to GVS occur only in balance tasks when proprioceptive feedback is congruent. This study using GVS in microgravity is the first to present an approach delineating feedforward vestibular control in unconstrained environment.NEW & NOTEWORTHY This study addresses the extent of conservation of trunk muscle control in humans. Results show that galvanic vestibular stimulation-evoked vestibular responses in trunk muscles remain strong in conditions where leg muscle responses are downmodulated (walking, standing, microgravity). This suggests a phylogenetically conserved blueprint of sensorimotor organization, with strongly hardwired vestibulospinal inputs to axial motoneurons and a higher degree of flexibility in the later emerging limb control system.
Collapse
Affiliation(s)
- Etienne Guillaud
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Université de Bordeaux, CNRS UMR 5287, Bordeaux, France
| | - Céline Faure
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Université de Bordeaux, CNRS UMR 5287, Bordeaux, France.,Center for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Emilie Doat
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Université de Bordeaux, CNRS UMR 5287, Bordeaux, France
| | - Laurent J Bouyer
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Dominique Guehl
- CHU de Bordeaux, Service d'explorations fonctionnelles du système nerveux, Bordeaux, France
| | - Jean-René Cazalets
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Université de Bordeaux, CNRS UMR 5287, Bordeaux, France
| |
Collapse
|
28
|
Piccolo C, Bakkum A, Marigold DS. Subthreshold stochastic vestibular stimulation affects balance-challenged standing and walking. PLoS One 2020; 15:e0231334. [PMID: 32275736 PMCID: PMC7147773 DOI: 10.1371/journal.pone.0231334] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/20/2020] [Indexed: 11/19/2022] Open
Abstract
Subthreshold stochastic vestibular stimulation (SVS) is thought to enhance vestibular sensitivity and improve balance. However, it is unclear how SVS affects standing and walking when balance is challenged, particularly when the eyes are open. It is also unclear how different methods to determine stimulation intensity influence the effects. We aimed to determine (1) whether SVS affects stability when balance is challenged during eyes-open standing and overground walking tasks, and (2) how the effects differ based on whether optimal stimulation amplitude is derived from sinusoidal or cutaneous threshold techniques. Thirteen healthy adults performed balance-unchallenged and balance-challenged standing and walking tasks with SVS (0–30 Hz zero-mean, white noise electrical stimulus) or sham stimulation. For the balance-challenged condition, participants had inflatable rubber hemispheres attached to the bottom of their shoes to reduce the control provided by moving the center of pressure under their base of support. In different blocks of trials, we set SVS intensity to either 50% of participants’ sinusoidal (motion) threshold or 80% of participants’ cutaneous threshold. SVS reduced medial-lateral trunk velocity root mean square in the balance-challenged (p < 0.05) but not in the balance-unchallenged condition during standing. Regardless of condition, SVS decreased step-width variability and marginally increased gait speed when walking with the eyes open (p < 0.05). SVS intensity had minimal effect on the standing and walking measures. Taken together, our results provide insight into the effectiveness of SVS at improving balance-challenged, eyes-open standing and walking performance in healthy adults.
Collapse
Affiliation(s)
- Chiara Piccolo
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Amanda Bakkum
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Daniel S. Marigold
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail:
| |
Collapse
|
29
|
Modulation of vestibular-evoked responses prior to simple and complex arm movements. Exp Brain Res 2020; 238:869-881. [PMID: 32157327 DOI: 10.1007/s00221-020-05760-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/21/2020] [Indexed: 10/24/2022]
Abstract
During destabilizing, voluntary arm movements, the vestibular system provides sensory cues related to head motion that are necessary to preserve upright balance. Although sensorimotor processing increases in accordance with task complexity during the preparation phase of reaching, it is unclear whether vestibular signals are also enhanced when maintaining postural control prior to the execution of a voluntary movement. To probe whether vestibular cues are a component of complexity-related increases in sensorimotor processing during movement preparation, vestibular-evoked responses to stochastic (0-25 Hz; root mean square = 1 mA) binaural, bipolar electrical vestibular stimulation (EVS) were examined. These responses were assessed using cumulant density function estimates in the upper and lower limbs prior to ballistic arm movements of varying complexity in both standing (experiment 1) and seated (experiment 2) conditions. In experiment 1, EVS-electromyography (EMG) cumulant density estimates surpassed 95% confidence intervals for biceps and triceps brachii, as well as the left and right medial gastrocnemius. For the latter two muscles, the responses were enhanced 10-18% with increased movement complexity. In experiment 2, the EVS-EMG cumulant density estimates also surpassed 95% confidence intervals in the upper limb, confirming the presence of vestibular-evoked responses while seated; however, the amplitude was significantly less than standing. This study demonstrates the vestibular system contributes to postural stability during the preparation phase of reaching. As such, vestibular-driven signals may be used to update an internal model for upcoming reaching tasks or to prepare for imminent postural disturbances.
Collapse
|
30
|
Khosravi‐Hashemi N, Forbes PA, Dakin CJ, Blouin J. Virtual signals of head rotation induce gravity‐dependent inferences of linear acceleration. J Physiol 2019; 597:5231-5246. [DOI: 10.1113/jp278642] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/03/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
| | - Patrick A. Forbes
- Department of NeuroscienceErasmus MCUniversity Medical Center Rotterdam Rotterdam The Netherlands
| | | | | |
Collapse
|
31
|
Sozzi S, Nardone A, Schieppati M. Vision Does Not Necessarily Stabilize the Head in Space During Continuous Postural Perturbations. Front Neurol 2019; 10:748. [PMID: 31354614 PMCID: PMC6635830 DOI: 10.3389/fneur.2019.00748] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022] Open
Abstract
Vision favors head stabilization in space during perturbations of standing balance. This is particularly obvious under conditions of continuous predictable perturbations as during sinusoidal antero-posterior (A-P) translations of the supporting platform. We tested here the hypothesis that under this condition the head can instead undergo large A-P oscillations, when a precision visual task is concurrently performed. We compared the head oscillations across four conditions while standing on a continuously translating platform. Eyes open (EO, no visual task), EO while reading a text fixed to the moving platform (EO-TP), EO while reading a text fixed to earth-ground (EO-TG), eyes-closed (EC). The platform translated at 0.2 and 0.6 Hz. Participants were young adult subjects, who received no particular instruction except reading the text aloud when required. Markers fixed on head, platform and text-sheet were captured by an optoelectronic device. We found that head oscillations were larger with EC than under all EO conditions. The oscillations were the least with EO and EO-TG, and intermediate with EO-TP. This was true under both low and high translation frequency, in spite of broadly smaller head oscillations at high frequency, common to all visual conditions. The distance between the head and the text was quite constant with EO-TP but fluctuated with EO-TG. The basic whole-body coordination features were moderately similar under all conditions, as assessed by the head-platform correlation coefficients and time lags. It appears that vision does not produce head stabilization in space when a concurrent visual task requiring focusing on a reading-text moving with the platform is performed. Contrary to traditional views centered on the stabilizing effect of vision under both static and dynamic conditions, the results show that head stabilization, normally ensuring a reference for inertial guidance for body balance, can be revoked by the CNS to allow performance of a non-postural task. This novel paradigm can shift long-standing views on the effect of vision on equilibrium control and be considered a potential exercise treatment for enhancing the multisensory integration process in people with balance problems.
Collapse
Affiliation(s)
- Stefania Sozzi
- Centro Studi Attività Motorie, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Antonio Nardone
- Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy
| | - Marco Schieppati
- Centro Studi Attività Motorie, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| |
Collapse
|
32
|
Zhang Y, Brenner E, Duysens J, Verschueren S, Smeets JBJ. Is the manual following response an attempt to compensate for inferred self-motion? Exp Brain Res 2019; 237:2549-2558. [PMID: 31342107 PMCID: PMC6751223 DOI: 10.1007/s00221-019-05607-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 07/16/2019] [Indexed: 11/30/2022]
Abstract
If the surrounding of a visual target unexpectedly starts to move during a fast goal-directed hand movement, the hand reflexively moves along with it. This is known as the ‘manual following response’. One explanation for this response is that it is a compensation for inferred self-motion in space. Previous studies have shown that background motion gives rise to both postural responses and deviations in goal-directed hand movements. To evaluate whether compensation for inferred self-motion is responsible for the manual responses we examined whether galvanic stimulation of the vestibular system would give rise to similar deviations in hand movements. Standing participants tried to quickly tap on targets that were presented on a horizontal screen. Participants could infer self-motion on some of the trials, either from galvanic vestibular stimulation or from background motion. Both perturbations took place during the hand movement. It took both the head and hand about 45 ms longer to respond to background motion than to respond to galvanic stimulation. The head responded in a similar manner to both types of perturbations. The hand responded about as expected to galvanic stimulation, but much more vigorously to background motion. Thus, the manual response to background motion is probably not a direct consequence of trying to compensate for inferred self-motion. Perhaps the manual following response is a consequence of an error in binding motion information to objects.
Collapse
Affiliation(s)
- Yajie Zhang
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands. .,Department of Rehabilitation Sciences, FaBer, KU Leuven, Leuven, Belgium.
| | - Eli Brenner
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Jacques Duysens
- Department of Kinesiology, FaBer, KU Leuven, Leuven, Belgium
| | - Sabine Verschueren
- Department of Rehabilitation Sciences, FaBer, KU Leuven, Leuven, Belgium
| | - Jeroen B J Smeets
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| |
Collapse
|
33
|
Ertl M, Boegle R. Investigating the vestibular system using modern imaging techniques-A review on the available stimulation and imaging methods. J Neurosci Methods 2019; 326:108363. [PMID: 31351972 DOI: 10.1016/j.jneumeth.2019.108363] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 02/06/2023]
Abstract
The vestibular organs, located in the inner ear, sense linear and rotational acceleration of the head and its position relative to the gravitational field of the earth. These signals are essential for many fundamental skills such as the coordination of eye and head movements in the three-dimensional space or the bipedal locomotion of humans. Furthermore, the vestibular signals have been shown to contribute to higher cognitive functions such as navigation. As the main aim of the vestibular system is the sensation of motion it is a challenging system to be studied in combination with modern imaging methods. Over the last years various different methods were used for stimulating the vestibular system. These methods range from artificial approaches like galvanic or caloric vestibular stimulation to passive full body accelerations using hexapod motion platforms, or rotatory chairs. In the first section of this review we provide an overview over all methods used in vestibular stimulation in combination with imaging methods (fMRI, PET, E/MEG, fNIRS). The advantages and disadvantages of every method are discussed, and we summarize typical settings and parameters used in previous studies. In the second section the role of the four imaging techniques are discussed in the context of vestibular research and their potential strengths and interactions with the presented stimulation methods are outlined.
Collapse
Affiliation(s)
- Matthias Ertl
- Department of Psychology, University of Bern, Switzerland; Sleep-Wake-Epilepsy Center, Department of Neurology, University Hospital (Inselspital) Bern, Switzerland.
| | - Rainer Boegle
- Department of Neurology, Ludwig-Maximilians-Universität München, Germany; German Center for Vertigo and Balance Disorders, IFB-LMU, Ludwig-Maximilians Universität, Munich, Germany
| |
Collapse
|
34
|
Bakker RS, Selen LPJ, Medendorp WP. Transformation of vestibular signals for the decisions of hand choice during whole body motion. J Neurophysiol 2019; 121:2392-2400. [PMID: 31017838 DOI: 10.1152/jn.00470.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In daily life, we frequently reach toward objects while our body is in motion. We have recently shown that body accelerations influence the decision of which hand to use for the reach, possibly by modulating the body-centered computations of the expected reach costs. However, head orientation relative to the body was not manipulated, and hence it remains unclear whether vestibular signals contribute in their head-based sensory frame or in a transformed body-centered reference frame to these cost calculations. To test this, subjects performed a preferential reaching task to targets at various directions while they were sinusoidally translated along the lateral body axis, with their head either aligned with the body (straight ahead) or rotated 18° to the left. As a measure of hand preference, we determined the target direction that resulted in equiprobable right/left-hand choices. Results show that head orientation affects this balanced target angle when the body is stationary but does not further modulate hand preference when the body is in motion. Furthermore, reaction and movement times were larger for reaches to the balanced target angle, resembling a competitive selection process, and were modulated by head orientation when the body was stationary. During body translation, reaction and movement times depended on the phase of the motion, but this phase-dependent modulation had no interaction with head orientation. We conclude that the brain transforms vestibular signals to body-centered coordinates at the early stage of reach planning, when the decision of hand choice is computed. NEW & NOTEWORTHY The brain takes inertial acceleration into account in computing the anticipated biomechanical costs that guide hand selection during whole body motion. Whereas these costs are defined in a body-centered, muscle-based reference frame, the otoliths detect the inertial acceleration in head-centered coordinates. By systematically manipulating head position relative to the body, we show that the brain transforms otolith signals into body-centered coordinates at an early stage of reach planning, i.e., before the decision of hand choice is computed.
Collapse
Affiliation(s)
- Romy S Bakker
- Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen , The Netherlands
| | - Luc P J Selen
- Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen , The Netherlands
| | - W Pieter Medendorp
- Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen , The Netherlands
| |
Collapse
|
35
|
Arntz AI, van der Putte DAM, Jonker ZD, Hauwert CM, Frens MA, Forbes PA. The Vestibular Drive for Balance Control Is Dependent on Multiple Sensory Cues of Gravity. Front Physiol 2019; 10:476. [PMID: 31114504 PMCID: PMC6503156 DOI: 10.3389/fphys.2019.00476] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/04/2019] [Indexed: 11/24/2022] Open
Abstract
Vestibular signals, which encode head movement in space as well as orientation relative to gravity, contribute to the ongoing muscle activity required to stand. The strength of this vestibular contribution changes with the presence and quality of sensory cues of balance. Here we investigate whether the vestibular drive for standing balance also depends on different sensory cues of gravity by examining vestibular-evoked muscle responses when independently varying load and gravity conditions. Standing subjects were braced by a backboard structure that limited whole-body sway to the sagittal plane while load and vestibular cues of gravity were manipulated by: (a) loading the body downward at 1.5 and 2 times body weight (i.e., load cues), and/or (b) exposing subjects to brief periods (20 s) of micro- (<0.05 g) and hyper-gravity (∼1.8 g) during parabolic flights (i.e., vestibular cues). A stochastic electrical vestibular stimulus (0–25 Hz) delivered during these tasks evoked a vestibular-error signal and corrective muscles responses that were used to assess the vestibular drive to standing balance. With additional load, the magnitude of the vestibular-evoked muscle responses progressively increased, however, when these responses were normalized by the ongoing muscle activity, they decreased and plateaued at 1.5 times body weight. This demonstrates that the increased muscle activity necessary to stand with additional load is accompanied a proportionally smaller increase in vestibular input. This reduction in the relative vestibular contribution to balance was also observed when we varied the vestibular cues of gravity, but only during an absence (<0.05 g) and not an excess (∼1.8 g) of gravity when compared to conditions with normal 1 g gravity signals and equivalent load signals. Despite these changes, vestibular-evoked responses were observed in all conditions, indicating that vestibular cues of balance contribute to upright standing even in the near absence of a vestibular signal of gravity (i.e., micro-gravity). Overall, these experiments provide evidence that both load and vestibular cues of gravity influence the vestibular signal processing for the control of standing balance.
Collapse
Affiliation(s)
- Anne I Arntz
- Department of Neuroscience, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands.,Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, Netherlands
| | - Daphne A M van der Putte
- Department of Neuroscience, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Zeb D Jonker
- Department of Neuroscience, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands.,Department of Rehabilitation Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands.,Rijndam Rehabilitation Centre, Rotterdam, Netherlands
| | - Christopher M Hauwert
- Department of Neuroscience, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Maarten A Frens
- Department of Neuroscience, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Patrick A Forbes
- Department of Neuroscience, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands.,Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, Netherlands
| |
Collapse
|
36
|
Kwan A, Forbes PA, Mitchell DE, Blouin JS, Cullen KE. Neural substrates, dynamics and thresholds of galvanic vestibular stimulation in the behaving primate. Nat Commun 2019; 10:1904. [PMID: 31015434 PMCID: PMC6478681 DOI: 10.1038/s41467-019-09738-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/21/2019] [Indexed: 11/09/2022] Open
Abstract
Galvanic vestibular stimulation (GVS) uses the external application of electrical current to selectively target the vestibular system in humans. Despite its recent popularity for the assessment/treatment of clinical conditions, exactly how this non-invasive tool activates the vestibular system remains an open question. Here we directly investigate single vestibular afferent responses to GVS applied to the mastoid processes of awake-behaving monkeys. Transmastoid GVS produces robust and parallel activation of both canal and otolith afferents. Notably, afferent activation increases with intrinsic neuronal variability resulting in constant GVS-evoked neuronal detection thresholds across all afferents. Additionally, afferent tuning differs for GVS versus natural self-motion stimulation. Using a stochastic model of repetitive activity in afferents, we largely explain the main features of GVS-evoked vestibular afferent dynamics. Taken together, our results reveal the neural substrate underlying transmastoid GVS-evoked perceptual, ocular and postural responses-information that is essential to advance GVS applicability for biomedical uses in humans.
Collapse
Affiliation(s)
- Annie Kwan
- Department of Biomedical Engineering, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Patrick A Forbes
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Rotterdam, 3000 CA, The Netherlands.,Department of BioMechanical Engineering, Delft University of Technology, Delft, 2628 CD, The Netherlands.,School of Kinesiology, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - Diana E Mitchell
- Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - Kathleen E Cullen
- Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, 21205, MD, USA.
| |
Collapse
|
37
|
Abstract
The upright stance position is inherently unstable since the smallest deviation from a perfect upright orientation produces forces due to gravity that accelerate the body toward the ground. Stability is achieved by generating appropriate joint torques that correct for deviations from a desired orientation with orientation changes detected by sensory systems (primarily somatosensory/proprioceptive, visual, and vestibular systems). Functionally, balance control can be viewed as a closed-loop feedback control system with the integration of different sources of sensory orientation information being one component of the overall system, but with the system's feedback nature placing constraints on the sensory integration process. Analysis of body sway evoked by balance perturbations allows for the measurement of "sensory weights" that represent the relative contributions of different sensory systems to an internal estimate of orientation that, in turn, is used to generate corrective actions. Experiments reveal that sensory weights are not fixed quantities, but vary as a function of environmental and experimental conditions as well as neurologic disorders that affect the quality of sensory information available from different sensory systems. Because environmental conditions can change rapidly, sensory reweighting must also occur rapidly enough to prevent instability due to an under- or overproduction of corrective action.
Collapse
|
38
|
Impact of extremely low-frequency magnetic fields on human postural control. Exp Brain Res 2018; 237:611-623. [DOI: 10.1007/s00221-018-5442-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 11/21/2018] [Indexed: 01/28/2023]
|
39
|
Rasman BG, Forbes PA, Tisserand R, Blouin JS. Sensorimotor Manipulations of the Balance Control Loop-Beyond Imposed External Perturbations. Front Neurol 2018; 9:899. [PMID: 30416481 PMCID: PMC6212554 DOI: 10.3389/fneur.2018.00899] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/03/2018] [Indexed: 12/22/2022] Open
Abstract
Standing balance relies on the integration of multiple sensory inputs to generate the motor commands required to stand. Mechanical and sensory perturbations elicit compensatory postural responses that are interpreted as a window into the sensorimotor processing involved in balance control. Popular methods involve imposed external perturbations that disrupt the control of quiet stance. Although these approaches provide critical information on how the balance system responds to external disturbances, the control mechanisms involved in correcting for these errors may differ from those responsible for the regulation of quiet standing. Alternative approaches use manipulations of the balance control loop to alter the relationship between sensory and motor cues. Coupled with imposed perturbations, these manipulations of the balance control loop provide unique opportunities to reveal how sensory and motor signals are integrated to control the upright body. In this review, we first explore imposed perturbation approaches that have been used to investigate the neural control of standing balance. We emphasize imposed perturbations that only elicit balance responses when the disturbing stimuli are relevant to the balance task. Next, we highlight manipulations of the balance control loop that, when carefully implemented, replicate and/or alter the sensorimotor dynamics of quiet standing. We further describe how manipulations of the balance control loop can be used in combination with imposed perturbations to characterize mechanistic principles underlying the control of standing balance. We propose that recent developments in the use of robotics and sensory manipulations will continue to enable new possibilities for simulating and/or altering the sensorimotor control of standing beyond compensatory responses to imposed external perturbations.
Collapse
Affiliation(s)
- Brandon G. Rasman
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Patrick A. Forbes
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, Netherlands
| | - Romain Tisserand
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
- Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
40
|
Zhang L, Feldman AG, Levin MF. Vestibular and corticospinal control of human body orientation in the gravitational field. J Neurophysiol 2018; 120:3026-3041. [PMID: 30207862 DOI: 10.1152/jn.00483.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Body orientation with respect to the direction of gravity changes when we lean forward from upright standing. We tested the hypothesis that during upright standing, the nervous system specifies the referent body orientation that defines spatial thresholds for activation of multiple muscles across the body. To intentionally lean the body forward, the system is postulated to transfer balance and stability to the leaned position by monotonically tilting the referent orientation, thus increasing the activation thresholds of ankle extensors and decreasing their activity. Consequently, the unbalanced gravitational torque would start to lean the body forward. With restretching, ankle extensors would be reactivated and generate increasing electromyographic (EMG) activity until the enhanced gravitational torque would be balanced at a new posture. As predicted, vestibular influences on motoneurons of ankle extensors evaluated by galvanic vestibular stimulation were smaller in the leaned compared with the upright position, despite higher tonic EMG activity. Defacilitation of vestibular influences was also observed during forward leaning when the EMG levels in the upright and leaned position were equalized by compensating the gravitational torque with a load. The vestibular system is involved in the active control of body orientation without directly specifying the motor outcome. Corticospinal influences originating from the primary motor cortex evaluated by transcranial magnetic stimulation remained similar at the two body postures. Thus, in contrast to the vestibular system, the corticospinal system maintains a similar descending facilitation of motoneurons of leg muscles at different body orientations. The study advances the understanding of how body orientation is controlled. NEW & NOTEWORTHY The brain changes the referent body orientation with respect to gravity to lean the body forward. Physiologically, this is achieved by shifts in spatial thresholds for activation of ankle muscles, which involves the vestibular system. Results advance the understanding of how the brain controls body orientation in the gravitational field. The study also extends previous evidence of empirical control of motor function, i.e., without the reliance on model-based computations and direct specification of motor outcome.
Collapse
Affiliation(s)
- Lei Zhang
- Department of Neuroscience, University of Montreal , Montreal, Quebec , Canada.,Institut de Réadaptation Gingras-Lindsay de Montréal, Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR) , Montreal, Quebec , Canada.,Jewish Rehabilitation Hospital, CRIR, Laval, Quebec , Canada
| | - Anatol G Feldman
- Department of Neuroscience, University of Montreal , Montreal, Quebec , Canada.,Institut de Réadaptation Gingras-Lindsay de Montréal, Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR) , Montreal, Quebec , Canada.,Jewish Rehabilitation Hospital, CRIR, Laval, Quebec , Canada
| | - Mindy F Levin
- Jewish Rehabilitation Hospital, CRIR, Laval, Quebec , Canada.,School of Physical and Occupational Therapy, McGill University , Montreal, Quebec , Canada
| |
Collapse
|
41
|
Tisserand R, Dakin CJ, Van der Loos MH, Croft EA, Inglis TJ, Blouin JS. Down regulation of vestibular balance stabilizing mechanisms to enable transition between motor states. eLife 2018; 7:36123. [PMID: 29989550 PMCID: PMC6056236 DOI: 10.7554/elife.36123] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/30/2018] [Indexed: 11/29/2022] Open
Abstract
The neural control of transition between posture and movement encompasses the regulation of reflex-stabilizing mechanisms to enable motion. Optimal feedback theory suggests that such transitions require the disengagement of one motor control policy before the implementation of another. To test this possibility, we investigated the continuity of the vestibular control of balance during transitions between quiet standing and locomotion and between two standing postures. Healthy subjects initiated and terminated locomotion or shifted the distribution of their weight between their feet, while exposed to electrical vestibular stimuli (EVS). The relationship between EVS and ground reaction forces was quantified using time-frequency analyses. Discontinuities corresponding to null coherence periods were observed preceding the onset of movement initiation and during the step preceding locomotion termination. These results show humans interrupt the vestibular balance stabilizing mechanisms to transition between motor states, suggesting a discrete change between motor control policies, as predicted by optimal feedback theory. Crossing Abbey Road is something of a paradox in neuroscientific terms. As you stand waiting to cross, tiny movements of your body – such as those due to breathing – cause you to sway by small amounts. To prevent you from falling over, your brain makes active corrections to your posture. These posture-correcting mechanisms oppose movements such as sway and keep you standing upright. But what happens when you want to cross the road? To get you moving, your brain has two options. It could temporarily suppress the posture-correcting mechanisms. Or it could reconfigure them so that they work in a different way. The posture-correcting mechanisms rely upon sensory input from various sources. These include the vestibular system of the inner ear. The vestibular system tells the brain about the position and movement of the head in space and relative to gravity. Monitoring vestibular system activity as a person starts to move should thus reveal what is happening to the posture-correcting mechanisms. Tisserand et al. asked healthy volunteers to transition between standing still and walking, or to shift their weight from one foot to the other. At the same time, small non-painful electric currents were applied to the bones behind the volunteers' ears. These currents induced small changes in vestibular system activity. Sensors in the floor measured the forces the volunteers generated while standing or walking, thereby revealing how they adjusted their balance. The results showed that the brain suppresses its posture-correcting mechanisms before people start or stop moving. These findings have implications for robotics. They could make it easier to program robots to show smooth transitions into and out of movement. The findings are also relevant to movement disorders such as Parkinson's disease. One common symptom of this disorder is freezing of gait, in which patients suddenly feel as though their feet are glued to the ground. Understanding how the brain controls movement transitions may reveal how such symptoms arise.
Collapse
Affiliation(s)
- Romain Tisserand
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Christopher J Dakin
- Department of Kinesiology and Health Science, Utah State University, Logan, United States
| | - Machiel Hf Van der Loos
- Department of Mechanical Engineering, University of British Columbia, Vancouver, Canada.,Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, Canada
| | | | - Timothy J Inglis
- School of Kinesiology, University of British Columbia, Vancouver, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, Canada.,Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| |
Collapse
|
42
|
Forbes PA, Fice JB, Siegmund GP, Blouin JS. Electrical Vestibular Stimuli Evoke Robust Muscle Activity in Deep and Superficial Neck Muscles in Humans. Front Neurol 2018; 9:535. [PMID: 30026725 PMCID: PMC6041388 DOI: 10.3389/fneur.2018.00535] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/18/2018] [Indexed: 01/01/2023] Open
Abstract
Neck muscle activity evoked by vestibular stimuli is a clinical measure for evaluating the function of the vestibular apparatus. Cervical vestibular-evoked myogenic potentials (cVEMP) are most commonly measured in the sternocleidomastoid muscle (and more recently the splenius capitis muscle) in response to air-conducted sound, bone-conducted vibration or electrical vestibular stimuli. It is currently unknown, however, whether and how other neck muscles respond to vestibular stimuli. Here we measured activity bilaterally in the sternocleidomastoid, splenius capitis, sternohyoid, semispinalis capitis, multifidus, rectus capitis posterior, and obliquus capitis inferior using indwelling electrodes in two subjects exposed to binaural bipolar electrical vestibular stimuli. All recorded neck muscles responded to the electrical vestibular stimuli (0–100 Hz) provided they were active. Furthermore, the evoked responses were inverted on either side of the neck, consistent with a coordinated contribution of all left-right muscle pairs acting as antagonists in response to the electrically-evoked vestibular error of head motion. Overall, our results suggest that, as previously observed in cat neck muscles, broad connections exist between the human vestibular system and neck motoneurons and highlight the need for future investigations to establish their neural connections.
Collapse
Affiliation(s)
- Patrick A Forbes
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, Netherlands.,Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, Netherlands
| | - Jason B Fice
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Gunter P Siegmund
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,MEA Forensic Engineers & Scientists, Richmond, BC, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
43
|
Wallace JW, Rasman BG, Dalton BH. Vestibular-Evoked Responses Indicate a Functional Role for Intrinsic Foot Muscles During Standing Balance. Neuroscience 2018. [PMID: 29524635 DOI: 10.1016/j.neuroscience.2018.02.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Maintaining standing balance involves multisensory processing and integration to produce dynamic motor responses. Electrical vestibular stimulation (EVS) delivered over the mastoid processes can be used to explore the vestibular control of balance. The purpose of this study was to determine whether intrinsic foot muscles exhibit vestibular-evoked balance responses and to characterize the traits associated with these responses. Electromyography (EMG) of the abductor hallucis (AH), abductor digiti minimi (ADM) and medial gastrocnemius (MG) and anterior-posterior (AP) forces were sampled while quietly standing participants were subjected to a random continuous EVS signal (peak-to-peak amplitude = ±3 mA). The relationship between EVS input and motor output was characterized in both the frequency (coherence) and time (cumulant density) domains. When head orientation was rotated in yaw from left to right, the biphasic cumulant density function was inverted for all muscle (EVS-EMG) and whole-body (EVS-AP forces) balance responses. When vision was occluded, the EVS-EMG and EVS-AP forces coherence function amplitude increased at low frequencies (<2 Hz) and was accompanied by a heightened medium-latency peak amplitude for all muscles as well as the whole-body balance response (AP forces) compared to when static visual cues were present. The enhanced coherence amplitudes at lower frequencies may highlight a mechanism for the increase in postural sway from vision to occluded vision. The current findings indicate that the vestibular control of standing balance can be represented by the intrinsic foot muscles and implicate a postural role for these muscles in modulating quiet standing.
Collapse
Affiliation(s)
- Jonathan W Wallace
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Brandon G Rasman
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian H Dalton
- Department of Human Physiology, University of Oregon, Eugene, OR, United States; School of Health and Exercise Sciences, The University of British Columbia, Kelowna, British Columbia, Canada.
| |
Collapse
|
44
|
Forbes PA, Chen A, Blouin JS. Sensorimotor control of standing balance. HANDBOOK OF CLINICAL NEUROLOGY 2018; 159:61-83. [DOI: 10.1016/b978-0-444-63916-5.00004-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
|
45
|
Lam CK, Staines WR, Tokuno CD, Bent LR. The medium latency muscle response to a vestibular perturbation is increased after depression of the cerebellar vermis. Brain Behav 2017; 7:e00782. [PMID: 29075558 PMCID: PMC5651382 DOI: 10.1002/brb3.782] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 06/06/2017] [Accepted: 06/12/2017] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION Galvanic vestibular stimulation (GVS) is able to evoke distinct responses in the muscles used for balance. These reflexes, termed the short (SL) and medium latency (ML) responses, can be altered by sensory input; decreasing in size when additional sensory cues are available. Although much is known about these responses, the origin and role of the responses are still not fully understood. It has been suggested that the cerebellum, a structure that is involved in postural control and sensory integration, may play a role in the modulation of these reflexes. METHODS The cerebellar vermis was temporarily depressed using continuous theta burst stimulation and SL, ML and overall vestibular electromyographic and force plate shear response amplitudes were compared before and after cerebellar depression. RESULTS There were no changes in force plate shear amplitude and a non-significant increase for the SL muscle response (p = .071), however, we did find significant increases in the ML and overall vestibular muscle response amplitudes after cerebellar depression (p = .026 and p = .016, respectively). No changes were evoked when a SHAM stimulus was used. DISCUSSION These results suggest that the cerebellar vermis plays a role in the modulation of vestibular muscle reflex responses to GVS.
Collapse
|
46
|
de Melker Worms JLA, Stins JF, Beek PJ, Loram ID. The effect of fear of falling on vestibular feedback control of balance. Physiol Rep 2017; 5:5/18/e13391. [PMID: 28963123 PMCID: PMC5617925 DOI: 10.14814/phy2.13391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 07/23/2017] [Accepted: 07/26/2017] [Indexed: 11/24/2022] Open
Abstract
Vestibular sensation contributes to cervical‐head stabilization and fall prevention. To what extent fear of falling influences the associated vestibular feedback processes is currently undetermined. We used galanic vestibular stimulation (GVS) to induce vestibular reflexes while participants stood at ground level and on a narrow walkway at 3.85 m height to induce fear of falling. Fear was confirmed by questionnaires and elevated skin conductance. Full‐body kinematics was measured to differentiate the whole‐body centre of mass response (CoM) into component parts (cervical, axial trunk, appendicular short latency, and medium latency). We studied the effect of fear of falling on each component to discern their underlying mechanisms. Statistical parametric mapping analysis provided sensitive discrimination of early GVS and height effects. Kinematic analysis revealed responses at 1 mA stimulation previously believed marginal through EMG and force plate analysis. The GVS response comprised a rapid, anode‐directed cervical‐head acceleration, a short‐latency cathode‐directed acceleration (cathodal buckling) of lower extremities and pelvis, an anode‐directed upper thorax acceleration, and subsequently a medium‐latency anode‐directed acceleration of all body parts. At height, head and upper thorax early acceleration were unaltered, however, short‐latency lower extremity acceleration was increased. The effect of height on balance was a decreased duration and increased rate of change in the CoM acceleration pattern. These results demonstrate that fear modifies vestibular control of balance, whereas cervical‐head stabilization is governed by different mechanisms unaffected by fear of falling. The mechanical pattern of cathodal buckling and its modulation by fear of falling both support the hypothesis that short‐latency responses contribute to regulate balance.
Collapse
Affiliation(s)
- Jonathan L A de Melker Worms
- Cognitive Motor Function research group School of Healthcare Science Manchester Metropolitan University, Manchester, United Kingdom
| | - John F Stins
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences Vrije Universiteit Amsterdam Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Peter J Beek
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences Vrije Universiteit Amsterdam Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Ian D Loram
- Cognitive Motor Function research group School of Healthcare Science Manchester Metropolitan University, Manchester, United Kingdom
| |
Collapse
|
47
|
Gimmon Y, Millar J, Pak R, Liu E, Schubert MC. Central not peripheral vestibular processing impairs gait coordination. Exp Brain Res 2017; 235:3345-3355. [PMID: 28819687 DOI: 10.1007/s00221-017-5061-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 08/08/2017] [Indexed: 11/29/2022]
Abstract
Gait coordination is generated by neuronal inter-connections between central pattern generators in the spinal cord governed by cortical areas. Malfunction of central vestibular processing areas generates vestibular symptoms in the absence of an identifiable peripheral vestibular system lesion. Walking in the dark enforces a coordinated afference primarily from the vestibular and somatosensory systems. We hypothesized that patients with aberrant central vestibular processing would demonstrate unique gait characteristics, and have impaired gait coordination compared with those patients with abnormal peripheral vestibular function and healthy controls. One-hundred and eighteen subjects were recruited. Peripheral vestibular function was determined based on laboratory and clinical examinations. Patients with abnormal central vestibular processing had normal peripheral vestibular function. Subjects were instructed to walk at a comfortable pace during three visual conditions; eyes open, eyes open and closed intermittently, and eyes closed. Both patient groups showed a similar spatiotemporal gait pattern, significantly different from the pattern of the healthy controls. However, only the central vestibular patient group had an abnormal coordination of gait as measured by the phase coordination index (PCI). There were no significant interactions between the groups and walking conditions. Peripheral vestibular deficits impair gait though our data suggest that it is the central processing of such peripheral vestibular information that has a greater influence. This impairment may be related to a neural un-coupling between the brain and central pattern generator of the spinal cord based on the abnormal PCI, which seems to be a good indicator of the integrity of this linkage.
Collapse
Affiliation(s)
- Yoav Gimmon
- Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, 601 N. Caroline Street, 6th Floor, Baltimore, MD, 21287-0910, USA
| | - Jennifer Millar
- Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rebecca Pak
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elizabeth Liu
- Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, 601 N. Caroline Street, 6th Floor, Baltimore, MD, 21287-0910, USA
| | - Michael C Schubert
- Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, 601 N. Caroline Street, 6th Floor, Baltimore, MD, 21287-0910, USA. .,Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
48
|
Dalton BH, Rasman BG, Inglis JT, Blouin J. The internal representation of head orientation differs for conscious perception and balance control. J Physiol 2017; 595:2731-2749. [PMID: 28035656 PMCID: PMC5390877 DOI: 10.1113/jp272998] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 11/12/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We tested perceived head-on-feet orientation and the direction of vestibular-evoked balance responses in passively and actively held head-turned postures. The direction of vestibular-evoked balance responses was not aligned with perceived head-on-feet orientation while maintaining prolonged passively held head-turned postures. Furthermore, static visual cues of head-on-feet orientation did not update the estimate of head posture for the balance controller. A prolonged actively held head-turned posture did not elicit a rotation in the direction of the vestibular-evoked balance response despite a significant rotation in perceived angular head posture. It is proposed that conscious perception of head posture and the transformation of vestibular signals for standing balance relying on this head posture are not dependent on the same internal representation. Rather, the balance system may operate under its own sensorimotor principles, which are partly independent from perception. ABSTRACT Vestibular signals used for balance control must be integrated with other sensorimotor cues to allow transformation of descending signals according to an internal representation of body configuration. We explored two alternative models of sensorimotor integration that propose (1) a single internal representation of head-on-feet orientation is responsible for perceived postural orientation and standing balance or (2) conscious perception and balance control are driven by separate internal representations. During three experiments, participants stood quietly while passively or actively maintaining a prolonged head-turned posture (>10 min). Throughout the trials, participants intermittently reported their perceived head angular position, and subsequently electrical vestibular stimuli were delivered to elicit whole-body balance responses. Visual recalibration of head-on-feet posture was used to determine whether static visual cues are used to update the internal representation of body configuration for perceived orientation and standing balance. All three experiments involved situations in which the vestibular-evoked balance response was not orthogonal to perceived head-on-feet orientation, regardless of the visual information provided. For prolonged head-turned postures, balance responses consistent with actual head-on-feet posture occurred only during the active condition. Our results indicate that conscious perception of head-on-feet posture and vestibular control of balance do not rely on the same internal representation, but instead treat sensorimotor cues in parallel and may arrive at different conclusions regarding head-on-feet posture. The balance system appears to bypass static visual cues of postural orientation and mainly use other sensorimotor signals of head-on-feet position to transform vestibular signals of head motion, a mechanism appropriate for most daily activities.
Collapse
Affiliation(s)
- Brian H. Dalton
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- School of Health and Exercise SciencesUniversity of British Columbia OkanaganKelownaBritish ColumbiaCanada
| | - Brandon G. Rasman
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - J. Timothy Inglis
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Djavad Mowafaghian Centre for Brain HealthUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- International Collaboration on Repair DiscoveriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Jean‐Sébastien Blouin
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Djavad Mowafaghian Centre for Brain HealthUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Institute for Computing, Information and Cognitive SystemsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| |
Collapse
|
49
|
Keyser J, Medendorp WP, Selen LPJ. Task-dependent vestibular feedback responses in reaching. J Neurophysiol 2017; 118:84-92. [PMID: 28356472 DOI: 10.1152/jn.00112.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 03/22/2017] [Accepted: 03/28/2017] [Indexed: 12/31/2022] Open
Abstract
When reaching for an earth-fixed object during self-rotation, the motor system should appropriately integrate vestibular signals and sensory predictions to compensate for the intervening motion and its induced inertial forces. While it is well established that this integration occurs rapidly, it is unknown whether vestibular feedback is specifically processed dependent on the behavioral goal. Here, we studied whether vestibular signals evoke fixed responses with the aim to preserve the hand trajectory in space or are processed more flexibly, correcting trajectories only in task-relevant spatial dimensions. We used galvanic vestibular stimulation to perturb reaching movements toward a narrow or a wide target. Results show that the same vestibular stimulation led to smaller trajectory corrections to the wide than the narrow target. We interpret this reduced compensation as a task-dependent modulation of vestibular feedback responses, tuned to minimally intervene with the task-irrelevant dimension of the reach. These task-dependent vestibular feedback corrections are in accordance with a central prediction of optimal feedback control theory and mirror the sophistication seen in feedback responses to mechanical and visual perturbations of the upper limb.NEW & NOTEWORTHY Correcting limb movements for external perturbations is a hallmark of flexible sensorimotor behavior. While visual and mechanical perturbations are corrected in a task-dependent manner, it is unclear whether a vestibular perturbation, naturally arising when the body moves, is selectively processed in reach control. We show, using galvanic vestibular stimulation, that reach corrections to vestibular perturbations are task dependent, consistent with a prediction of optimal feedback control theory.
Collapse
Affiliation(s)
- Johannes Keyser
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - W Pieter Medendorp
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Luc P J Selen
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| |
Collapse
|
50
|
Forbes PA, Vlutters M, Dakin CJ, van der Kooij H, Blouin J, Schouten AC. Rapid limb-specific modulation of vestibular contributions to ankle muscle activity during locomotion. J Physiol 2017; 595:2175-2195. [PMID: 28008621 PMCID: PMC5350434 DOI: 10.1113/jp272614] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 12/16/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The vestibular influence on human walking is phase-dependent and modulated across both limbs with changes in locomotor velocity and cadence. Using a split-belt treadmill, we show that vestibular influence on locomotor activity is modulated independently in each limb. The independent vestibular modulation of muscle activity from each limb occurs rapidly at the onset of split-belt walking, over a shorter time course relative to the characteristic split-belt error-correction mechanisms (i.e. muscle activity and kinematics) associated with locomotor adaptation. Together, the present results indicate that the nervous system rapidly modulates the vestibular influence of each limb separately through processes involving ongoing sensory feedback loops. These findings help us understand how vestibular information is used to accommodate the variable and commonplace demands of locomotion, such as turning or navigating irregular terrain. ABSTRACT During walking, the vestibular influence on locomotor activity is phase-dependent and modulated in both limbs with changes in velocity. It is unclear, however, whether this bilateral modulation is due to a coordinated mechanism between both limbs or instead through limb-specific processes that remain masked by the symmetric nature of locomotion. Here, human subjects walked on a split-belt treadmill with one belt moving at 0.4 m s-1 and the other moving at 0.8 m s-1 while exposed to an electrical vestibular stimulus. Muscle activity was recorded bilaterally around the ankles of each limb and used to compare vestibulo-muscular coupling between velocity-matched and unmatched tied-belt walking. In general, response magnitudes decreased by ∼20-50% and occurred ∼13-20% earlier in the stride cycle at the higher belt velocity. This velocity-dependent modulation of vestibular-evoked muscle activity was retained during split-belt walking and was similar, within each limb, to velocity-matched tied-belt walking. These results demonstrate that the vestibular influence on ankle muscles during locomotion can be adapted independently to each limb. Furthermore, modulation of vestibular-evoked muscle responses occurred rapidly (∼13-34 strides) after onset of split-belt walking. This rapid adaptation contrasted with the prolonged adaptation in step length symmetry (∼128 strides) as well as EMG magnitude and timing (∼40-100 and ∼20-70 strides, respectively). These results suggest that vestibular influence on ankle muscle control is adjusted rapidly in sensorimotor control loops as opposed to longer-term error correction mechanisms commonly associated with split-belt adaptation. Rapid limb-specific sensorimotor feedback adaptation may be advantageous for asymmetric overground locomotion, such as navigating irregular terrain or turning.
Collapse
Affiliation(s)
- Patrick A. Forbes
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials EngineeringDelft University of TechnologyDelftThe Netherlands
- Department of NeuroscienceErasmus Medical CentreRotterdamThe Netherlands
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Mark Vlutters
- Laboratory of Biomechanical Engineering, Institute for Biomedical Technology and Technical Medicine (MIRA)University of TwenteEnschedeThe Netherlands
| | - Christopher J. Dakin
- Sobell Department of Motor Neuroscience and Movement DisordersUniversity College London Institute of NeurologyLondonUK
- Department of Kinesiology and Health ScienceUtah State UniversityLoganUtahUSA
| | - Herman van der Kooij
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials EngineeringDelft University of TechnologyDelftThe Netherlands
- Laboratory of Biomechanical Engineering, Institute for Biomedical Technology and Technical Medicine (MIRA)University of TwenteEnschedeThe Netherlands
| | - Jean‐Sébastien Blouin
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Djavad Mowafaghian Centre for Brain HealthUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Institute for Computing, Information and Cognitive SystemsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Alfred C. Schouten
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials EngineeringDelft University of TechnologyDelftThe Netherlands
- Laboratory of Biomechanical Engineering, Institute for Biomedical Technology and Technical Medicine (MIRA)University of TwenteEnschedeThe Netherlands
| |
Collapse
|