A Distinctive Platform System to Study the Effects of a Vestibular Prosthesis on Nonhuman Primate Postural Control

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Lara A. Thompson ◽  
Csilla Haburcakova ◽  
Richard F. Lewis
Keyword(s):  
Nonhuman Primate ◽  
Nonhuman Primates ◽  
Vestibular Function ◽  
Support Surface ◽  
Blurred Vision ◽  
Vestibular Loss ◽  
Vestibular Prosthesis ◽  
Surface Conditions ◽  
Postural Responses ◽  
Platform System

The purpose of this paper is to describe novel experiments and methodologies utilizing a distinctive balance platform system to investigate postural responses for moderate to severe vestibular loss and invasive vestibular prosthesis-assisted nonhuman primates (rhesus monkeys). For several millions of vestibular loss sufferers in the U.S., daily living is severely affected in that common everyday tasks, such as getting out of bed at night, maintaining balance on a moving bus, or walking on an uneven surface, may cause a loss of stability leading to falls and injury. Aside from loss of balance, blurred vision and vertigo (perceived spinning sensation) are also debilitating in vestibular-impaired individuals. Although the need for vestibular rehabilitative solutions is apparent, postural responses for a broad range of peripheral vestibular function, and for various stationary and moving support conditions, have not been systematically investigated. For the investigation of implants and prostheses that are being developed toward implementation in humans, nonhuman primates are a key component. The measurement system used in this research was unique. Our platform system facilitated the study of rhesus monkey posture for stationary support surface conditions (quiet stance and head turns) and for dynamic support surface conditions (pseudorandom roll tilts of the support surface). Further, the platform system was used to systematically study postural responses that will serve as baseline measures for future vestibular-focused human and nonhuman primate posture studies.

A Novel Platform-System to Study the Effects of a Vestibular Prosthesis on Non-Human Primate Postural Control

2017 ◽  
Author(s):  
Lara A. Thompson ◽  
Csilla Haburcakova ◽  
Richard F. Lewis
Keyword(s):  
Animal Experiments ◽  
Vestibular Function ◽  
Support Surface ◽  
Blurred Vision ◽  
Vestibular Loss ◽  
Vestibular Prosthesis ◽  
Surface Conditions ◽  
Postural Responses ◽  
Platform System ◽  
Human Primate

For the several millions of vestibular loss sufferers nationwide, daily-living is severely affected in that common everyday tasks, such as getting out of bed at night, maintaining balance on a moving bus, or walking on an uneven surface, may cause loss of stability leading to falls and injury. Aside from loss of balance, blurred vision and vertigo (perceived spinning sensation) are also extremely debilitating in vestibular impaired individuals. For the investigation of implants and prostheses that are being developed towards implementation in humans, non-human primates are a key component. The purpose of our study was to implement a distinctive balance platform-system to investigate postural responses for moderate to severe vestibular loss and invasive vestibular prosthesis-assisted non-human primates (rhesus monkeys) for test balance conditions of various task-difficulty levels. Although the need for vestibular rehabilitative solutions is apparent, postural responses for a broad range of peripheral vestibular function, and for various stationary and moving support conditions, have not been systematically investigated. The measurement system used in this research was unique in that it allowed us to conduct animal experiments, not investigated previously; such experiments are necessary towards the development on an invasive vestibular prosthesis to be used in humans suffering from vestibular loss. Our platform-system facilitated the study of rhesus monkey posture for stationary support surface conditions (i.e., quiet stance and head turns; more versus fewer footplate cues and large versus small base-of-support) and for dynamic support surface conditions (i.e., pseudorandom roll-tilts of the support surface). Further, the platform-system was used to systematically study postural responses that will serve as baseline measures for future vestibular-focused human and non-human primate posture studies.

scholarly journals An Engineering Model to Test for Sensory Reweighting: Nonhuman Primates Serve as a Model for Human Postural Control and Vestibular Dysfunction

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Lara A. Thompson ◽  
Csilla Haburcakova ◽  
Adam D. Goodworth ◽  
Richard F. Lewis
Keyword(s):  
Control System ◽  
Rhesus Monkey ◽  
Postural Control ◽  
Nonhuman Primate ◽  
Nonhuman Primates ◽  
Balance Control ◽  
Vestibular Dysfunction ◽  
Sensory Reweighting ◽  
Vestibular Loss ◽  
Roll Tilt

Quantitative animal models are critically needed to provide proof of concept for the investigation of rehabilitative balance therapies (e.g., invasive vestibular prostheses) and treatment response prior to, or in conjunction with, human clinical trials. This paper describes a novel approach to modeling the nonhuman primate postural control system. Our observation that rhesus macaques and humans have even remotely similar postural control motivates the further application of the rhesus macaque as a model for studying the effects of vestibular dysfunction, as well as vestibular prosthesis-assisted states, on human postural control. Previously, system identification methodologies and models were only used to describe human posture. However, here we utilized pseudorandom, roll-tilt balance platform stimuli to perturb the posture of a rhesus monkey in normal and mild vestibular (equilibrium) loss states. The relationship between rhesus monkey trunk sway and platform roll-tilt was determined via stimulus–response curves and transfer function results. A feedback controller model was then used to explore sensory reweighting (i.e., changes in sensory reliance), which prevented the animal from falling off of the tilting platform. Conclusions involving sensory reweighting in the nonhuman primate for a normal sensory state and a state of mild vestibular loss led to meaningful insights. This first-phase effort to model the balance control system in nonhuman primates is essential for future investigations toward the effects of invasive rehabilitative (balance) technologies on postural control in primates, and ultimately, humans.

Primate Vocal Communication and the Evolution of Speech

2021 ◽  
Vol 30 (1) ◽  
pp. 55-60
Author(s):  
Julia Fischer
Keyword(s):  
Nonhuman Primate ◽  
Nonhuman Primates ◽  
Vocal Communication ◽  
Internal State ◽  
Multiple Sources ◽  
Primate Communication ◽  
Evolution Of Speech ◽  
Primate Vocal Communication ◽  
Species Specific ◽  
Shed Light

Studies of nonhuman primate communication are often motivated by the desire to shed light on the evolution of speech. In contrast to human speech, the vocal repertoires of nonhuman primates are evolutionarily highly conserved. Within species-specific constraints, calls may vary in relation to the internal state of the caller or social experience. Receivers can use signalers’ calls to predict upcoming events or behavioral dispositions. Yet nonhuman primates do not appear to express or comprehend communicative or informative intent. Signalers are sensitive to the relation between their own actions and receivers’ responses, and thus, signaling behavior can be conceived as goal directed. Receivers’ ability to integrate information from multiple sources renders the system flexible and powerful. Researchers who take a linguistic or biological perspective on nonhuman primate communication should be aware of the strengths and limitations of their approaches. Both benefit from a focus on the mechanisms that underpin signaling and responses to signals.

First trial and StartReact effects induced by balance perturbations to upright stance

2013 ◽  
Vol 110 (9) ◽  
pp. 2236-2245 ◽  
Author(s):  
A. D. Campbell ◽  
J. W. Squair ◽  
R. Chua ◽  
J. T. Inglis ◽  
M. G. Carpenter
Keyword(s):  
Startle Response ◽  
Support Surface ◽  
Wrist Movement ◽  
Repeated Presentation ◽  
Trial Effect ◽  
Acoustic Stimuli ◽  
Postural Responses ◽  
Startreact Effect ◽  
Startling Stimulus ◽  
Repeated Test

Postural responses (PR) to a balance perturbation differ between the first and subsequent perturbations. One explanation for this first trial effect is that perturbations act as startling stimuli that initiate a generalized startle response (GSR) as well as the PR. Startling stimuli, such as startling acoustic stimuli (SAS), are known to elicit GSRs, as well as a StartReact effect, in which prepared movements are initiated earlier by a startling stimulus. In this study, a StartReact effect paradigm was used to determine if balance perturbations can also act as startle stimuli. Subjects completed two blocks of simple reaction time trials involving wrist extension to a visual imperative stimulus (IS). Each block included 15 CONTROL trials that involved a warning cue and subsequent IS, followed by 10 repeated TEST trials, where either a SAS (TESTSAS) or a toes-up support-surface rotation (TESTPERT) was presented coincident with the IS. StartReact effects were observed during the first trial in both TESTSAS and TESTPERT conditions as evidenced by significantly earlier wrist movement and muscle onsets compared with CONTROL. Likewise, StartReact effects were observed in all repeated TESTSAS and TESTPERT trials. In contrast, GSRs in sternocleidomastoid and PRs were large in the first trial, but significantly attenuated over repeated presentation of the TESTPERT trials. Results suggest that balance perturbations can act as startling stimuli. Thus first trial effects are likely PRs which are superimposed with a GSR that is initially large, but habituates over time with repeated exposure to the startling influence of the balance perturbation.

Assessing head acceleration to identify a motor threshold to galvanic vestibular stimulation

2021 ◽  
Author(s):  
Youstina Mikhail ◽  
Jonathan Charron ◽  
Jean-Marc Mac Thiong ◽  
Dorothy Barthélemy
Keyword(s):  
Center Of Pressure ◽  
Vestibular Function ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Head Acceleration ◽  
Motor Threshold ◽  
Recruitment Curve ◽  
Eyes Closed ◽  
Postural Responses ◽  
Significant Difference

Galvanic vestibular stimulation (GVS) is used to assess vestibular function, but vestibular responses can exhibit variability depending on protocols or intensities used. We measured head acceleration in healthy subjects to identify an objective motor threshold on which to base GVS intensity when assessing postural responses. Thirteen healthy right-handed subjects stood on a force platform, eyes closed, head facing forward. An accelerometer was placed on the vertex to detect head acceleration, and electromyography activity of the right soleus was recorded. GVS (200 ms; current steps 0.5;1-4mA) was applied in a binaural and bipolar configuration. 1) GVS induced a biphasic accelerometer response at a latency of 15 ms. Based on response amplitude, we constructed a recruitment curve for all participants and determined the motor threshold. In parallel, the method of limits was used to devise a more rapid approach to determine motor threshold. 2) We observed significant differences between motor threshold based on therecruitment curve and perceptual thresholds (sensation/perception of movement). No significant difference was observed between the motor threshold based on the method of limits and perceptual thresholds . 3) Using orthogonal polynomial contrasts, we observed a linear progression between multiples of the objective motor threshold (0.5, 0.75, 1, 1.5x motor threshold) and the 95% confidence ellipse area, the first peak of center of pressure velocity, and the short and medium latency responses in the soleus. Hence, an objective motor threshold and a recruitment curve for GVS were determined based on head acceleration, which could increase understanding of the vestibular system.

Organization of postural responses following a rotational support surface perturbation, after TKA: Sagittal plane rotations

2007 ◽  
Vol 25 (1) ◽  
pp. 112-120 ◽  
Author(s):  
William H. Gage ◽  
James S. Frank ◽  
Stephen D. Prentice ◽  
Peter Stevenson
Keyword(s):  
Sagittal Plane ◽  
Support Surface ◽  
Surface Perturbation ◽  
Postural Responses

scholarly journals Finding a Balance: A Systematic Review of the Biomechanical Effects of Vestibular Prostheses on Stability in Humans

2020 ◽  
Vol 5 (2) ◽  
pp. 23
Author(s):  
Felix Haxby ◽  
Mohammad Akrami ◽  
Reza Zamani
Keyword(s):  
Vestibular System ◽  
Postural Sway ◽  
Vestibular Function ◽  
Vestibular Stimulation ◽  
Significant Heterogeneity ◽  
Vestibular Loss ◽  
Ocular Reflex ◽  
Gait Characteristics ◽  
Vestibulo Ocular Reflex ◽  
Meta Analyses

The vestibular system is located in the inner ear and is responsible for maintaining balance in humans. Bilateral vestibular dysfunction (BVD) is a disorder that adversely affects vestibular function. This results in symptoms such as postural imbalance and vertigo, increasing the incidence of falls and worsening quality of life. Current therapeutic options are often ineffective, with a focus on symptom management. Artificial stimulation of the vestibular system, via a vestibular prosthesis, is a technique being explored to restore vestibular function. This review systematically searched for literature that reported the effect of artificial vestibular stimulation on human behaviours related to balance, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) technique. A total of 21 papers matched the inclusion criteria of the literature search conducted using the PubMed and Web of Science databases (February 2019). The populations for these studies included both healthy adults and patients with BVD. In every paper, artificial vestibular stimulation caused an improvement in certain behaviours related to balance, although the extent of the effect varied greatly. Various behaviours were measured such as the vestibulo-ocular reflex, postural sway and certain gait characteristics. Two classes of prosthesis were evaluated and both showed a significant improvement in at least one aspect of balance-related behaviour in every paper included. No adverse effects were reported for prostheses using noisy galvanic vestibular stimulation, however, prosthetic implantation sometimes caused hearing or vestibular loss. Significant heterogeneity in methodology, study population and disease aetiology were observed. The present study confirms the feasibility of vestibular implants in humans for restoring balance in controlled conditions, but more research needs to be conducted to determine their effects on balance in non-clinical settings.

scholarly journals Different Visual Weighting due to Fast or Slow Vestibular Deafferentation: Before and after Schwannoma Surgery

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Fredrik Tjernström ◽  
Per-Anders Fransson ◽  
Babar Kahlon ◽  
Mikael Karlberg ◽  
Sven Lindberg ◽  
...  
Keyword(s):  
Postural Control ◽  
Spatial Orientation ◽  
Visual Cues ◽  
Time Course ◽  
Vestibular Function ◽  
Sensory Systems ◽  
Vestibular Loss ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Background. Feedback postural control depends upon information from somatosensation, vision, and the vestibular system that are weighted depending on their relative importance within the central nervous system. Following loss of any sensory component, the weighting changes, e.g., when suffering a vestibular loss, the most common notion is that patients become more dependent on visual cues for maintaining postural control. Dizziness and disequilibrium are common after surgery in schwannoma patients, which could be due to interpretation of the remaining sensory systems involved in feedback-dependent postural control and spatial orientation. Objective. To compare visual dependency in spatial orientation and postural control in patients suffering from unilateral vestibular loss within different time frames. Methods. Patients scheduled for schwannoma surgery: group 1 (n=27) with no vestibular function prior to surgery (lost through years), group 2 (n=12) with remaining vestibular function at the time of surgery (fast deafferentation), and group 3 (n=18) with remaining function that was lost through gentamicin installations in the middle ear (slow deafferentation). All patients performed vibratory posturography and rod and frame investigation before surgery and 6 months after surgery. Results. Postural control improved after surgery in patients that suffered a slow deafferentation (groups 1 and 3) (p<0.001). Patients that suffered fast loss of remaining vestibular function (group 2) became less visual field dependent after surgery (p≤0.035) and were less able to maintain stability compared with group 1 (p=0.010) and group 3 (p=0.010). Conclusions. The nature and time course of vestibular deafferentation influence the weighting of remaining sensory systems in order to maintain postural control and spatial orientation.

Activity of neuromuscular compartments in lateral gastrocnemius evoked by postural corrections during stance

1993 ◽  
Vol 70 (6) ◽  
pp. 2337-2349 ◽  
Author(s):  
D. C. Dunbar ◽  
J. M. Macpherson
Keyword(s):  
Three Dimensional ◽  
Area Under The Curve ◽  
Gluteus Medius ◽  
Emg Activity ◽  
Support Surface ◽  
Lateral Gastrocnemius ◽  
Tuning Curves ◽  
Postural Responses ◽  
Upward Displacement ◽  
Neuromuscular Compartments

1. The electromyographic (EMG) activity of the four neuromuscular compartments in lateral gastrocnemius (LG) of cats was investigated to determine whether these intramuscular subdivisions could be activated differentially during automatic postural corrections. EMG electrodes were surgically implanted into each of the four compartments of left LG-LG1, LG2, LG3, and LGm--in two cats. Electrodes were also implanted into soleus and gluteus medius for comparative purposes. 2. Quiet quadrupedal stance was disturbed first by linearly translating the cats on a movable platform in each of 16 different horizontal directions. Mechanical events during corrections were characterized in terms of the three-dimensional forces exerted by each paw on the platform. EMG and force traces were quantified (area under the curve) and normalized, and tuning curves were constructed that relate muscle response and force change to direction of platform movement. 3. In a second series of trials, translations were presented along one direction only over a series of six velocities ranging from 5 to 16 cm/s. The third series of perturbations, termed the pop-up, consisted of a rapid upward displacement of the support under the left hindlimb only over a series of six amplitudes ranging from 1 to 10 mm. Evoked EMG activity and average change in force were normalized and regressions were computed onto velocity and amplitude, respectively. The slopes of the regressions were compared. 4. EMG tuning curves associated with the multidirectional horizontal translations revealed no differential activity across LG compartments. Similarly, there was no statistical difference among the slopes of the regressions within LG. In contrast, soleus exhibited significantly different slopes from LG for the regressions. Thus it is concluded that LG compartments are not differentially activated during automatic postural responses to perturbations of the support surface.

scholarly journals Kinematic Strategies in Newly Walking Toddlers Stepping Over Different Support Surfaces

2010 ◽  
Vol 103 (3) ◽  
pp. 1673-1684 ◽  
Author(s):  
Nadia Dominici ◽  
Yuri P. Ivanenko ◽  
Germana Cappellini ◽  
Maria Luisa Zampagni ◽  
Francesco Lacquaniti
Keyword(s):  
Degrees Of Freedom ◽  
Walking Speed ◽  
Search Space ◽  
Systematic Change ◽  
Support Surface ◽  
Coordination Pattern ◽  
Surface Conditions ◽  
Surface Inclination ◽  
Support Surfaces ◽  
Inclined Surface

In adults, locomotor movements are accommodated to various support surface conditions by means of specific anticipatory locomotor adjustments and changes in the intersegmental coordination. Here we studied the kinematic strategies of toddlers at the onset of independent walking when negotiating various support surface conditions: stepping over an obstacle, walking on an inclined surface, and on a staircase. Generally, toddlers could perform these tasks only when supported by the arm. They exhibited strategies very different from those of the adults. Although adults maintained walking speed roughly constant, toddlers markedly accelerated when walking downhill or downstairs and decelerated when walking uphill or upstairs. Their coordination pattern of thigh–shank–foot elevation angles exhibited greater inter-trial variability than that in adults, but it did not undergo the systematic change as a function of task that was present in adults. Thus the intersegmental covariance plane rotated across tasks in adults, whereas its orientation remained roughly constant in toddlers. In contrast with the adults, the toddlers often tended to place the foot onto the obstacle or across the edges of the stairs. We interpret such foot placements as part of a haptic exploratory repertoire and we argue that the maintenance of a roughly constant planar covariance—irrespective of the surface inclination and height—may be functional to the exploratory behavior. The latter notion is consistent with the hypothesis proposed decades ago by Bernstein that, when humans start to learn a skill, they may restrict the number of degrees of freedom to reduce the size of the search space and simplify the coordination.

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