Off-vertical Axis Rotation Research Articles

ABSTRACT: IMPROVEMENT IN SYMPTOMS AND COGNITIVE MEASUREMENTS IN A HIGH SCHOOL HOCKEY PLAYER WITH PRTOTRACTED CONCUSSION SYMPTOMS

Event Abstract Back to Event ABSTRACT: IMPROVEMENT IN SYMPTOMS AND COGNITIVE MEASUREMENTS IN A HIGH SCHOOL HOCKEY PLAYER WITH PRTOTRACTED CONCUSSION SYMPTOMS Matthew Antonucci1, 2*, Chris M. Sass1, 2 and Brian J. Sass1, 2 1 Plasticity Brain Centers, United States 2 Carrick Institute for Graduate Studies, United States Background: An 18 year old, high school, male hockey player, with a history of 7 documented concussions, presented with symptoms of headache, “brain fog”, and sluggishness. Graded Symptom Checklist (GSC) severity was a 14/138. Standard Assessment of Cognition (SAC) was scored at 21/30. Trails A (TA) and Trails B (TB) had scores of 22.3 sec and 51.8 seconds respectively; Trails AB Difference (TB-A) was 29.5 sec. Processing Speed (PS) score was a 52/80. Choice Reaction Time (cRT) latency was 462 milliseconds. Methods: A four-day, multi-modal program of neurological rehabilitation was administered three times per day, for one hour per session. Each session consisted of electrical somatosensory stimulation, neuromuscular reeducation exercises, vestibular rehabilitation exercises, off-vertical axis rotation, and eye exercises. Results: At the end of four days of treatment there was complete resolution of symptoms; GSC severity (-100%). The patient had an increased SAC score (+28.6%), decreased TA time (-19.3%), decreased TB time (-25.3%), TB-A decreased (-29.8%), increased PS score (+21.2%), and decreased cRT latency (-21.2%). Conclusion: Short duration, multi-modal, intensive programs of neurological rehabilitation may be a viable method to improve neurological integrity and performance in individuals with protracted concussive deficits. The authors suggest further investigation into short duration, multi-modal, intensive approaches to restoring neurological function in individuals suffering from mild traumatic brain injury (mTBI). Keywords: Keywords: performance enhancement, Vestibular Rehabilitation, balance, Visual Acuity, Cognition Conference: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration, Orlando, Florida, United States, 10 Dec - 14 Dec, 2015. Presentation Type: Poster Presentation Topic: Case Reports for Poster Presentation Citation: Antonucci M, Sass CM and Sass BJ (2015). ABSTRACT: IMPROVEMENT IN SYMPTOMS AND COGNITIVE MEASUREMENTS IN A HIGH SCHOOL HOCKEY PLAYER WITH PRTOTRACTED CONCUSSION SYMPTOMS. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration. doi: 10.3389/conf.fneur.2015.58.00046 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Oct 2015; Published Online: 02 Nov 2015. * Correspondence: Dr. Matthew Antonucci, Plasticity Brain Centers, Orlando, United States, mantonucci@carrickinstitute.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Matthew Antonucci Chris M Sass Brian J Sass Google Matthew Antonucci Chris M Sass Brian J Sass Google Scholar Matthew Antonucci Chris M Sass Brian J Sass PubMed Matthew Antonucci Chris M Sass Brian J Sass Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

IMPROVEMENT IN SYMPTOMS AND COGNITIVE MEASUREMENTS IN A HIGH SCHOOL HOCKEY PLAYER WITH PROTRACTED CONCUSSION SYMPTOMS

Event Abstract Back to Event IMPROVEMENT IN SYMPTOMS AND COGNITIVE MEASUREMENTS IN A HIGH SCHOOL HOCKEY PLAYER WITH PROTRACTED CONCUSSION SYMPTOMS Matthew Antonucci1, 2*, Chris M. Sass1, 2 and Brian J. Sass1, 2 1 Plasticity Brain Centers, United States 2 Carrick Institute for Graduate Studies, United States Background: An 18 year old, high school, male hockey player, with a history of 7 documented concussions, presented with symptoms of headache, “brain fog”, and sluggishness. Graded Symptom Checklist (GSC) severity was a 14/138. Standard Assessment of Cognition (SAC) was scored at 21/30. Trails A (TA) and Trails B (TB) had scores of 22.3 sec and 51.8 seconds respectively; Trails AB Difference (TB-A) was 29.5 sec. Processing Speed (PS) score was a 52/80. Choice Reaction Time (cRT) latency was 462 milliseconds. Methods: A four-day, multi-modal program of neurological rehabilitation was administered three times per day, for one hour per session. Each session consisted of electrical somatosensory stimulation, neuromuscular reeducation exercises, vestibular rehabilitation exercises, off-vertical axis rotation, and eye exercises. Results: At the end of four days of treatment there was complete resolution of symptoms; GSC severity (-100%). The patient had an increased SAC score (+28.6%), decreased TA time (-19.3%), decreased TB time (-25.3%), TB-A decreased (-29.8%), increased PS score (+21.2%), and decreased cRT latency (-21.2%). Conclusion: Short duration, multi-modal, intensive programs of neurological rehabilitation may be a viable method to improve neurological integrity and performance in individuals with protracted concussive deficits. The authors suggest further investigation into short duration, multi-modal, intensive approaches to restoring neurological function in individuals suffering from mild traumatic brain injury (mTBI). Keywords: performance enhancement, Vestibular Rehabilitation, balance, Visual Acuity, Cognition Conference: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration, Orlando, Florida, United States, 10 Dec - 14 Dec, 2015. Presentation Type: Poster Presentation Topic: Case Reports for Poster Presentation Citation: Antonucci M, Sass CM and Sass BJ (2015). IMPROVEMENT IN SYMPTOMS AND COGNITIVE MEASUREMENTS IN A HIGH SCHOOL HOCKEY PLAYER WITH PROTRACTED CONCUSSION SYMPTOMS. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration. doi: 10.3389/conf.fneur.2015.58.00059 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Oct 2015; Published Online: 02 Nov 2015. * Correspondence: Dr. Matthew Antonucci, Plasticity Brain Centers, Orlando, Florida, United States, mantonucci@carrickinstitute.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Matthew Antonucci Chris M Sass Brian J Sass Google Matthew Antonucci Chris M Sass Brian J Sass Google Scholar Matthew Antonucci Chris M Sass Brian J Sass PubMed Matthew Antonucci Chris M Sass Brian J Sass Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

BRAIN-BASED TREATMENT OF CHRONIC LEG PAIN AND IMBALANCE IN A MIDDLE-AGED FEMALE.

Event Abstract Back to Event BRAIN-BASED TREATMENT OF CHRONIC LEG PAIN AND IMBALANCE IN A MIDDLE-AGED FEMALE. Susan Esposito1*, Julie Jordan1 and Linda Mullin Elkins1 1 Life University, United States Background: A middle-aged female presented to a university functional neurology clinic with a chief complaint of chronic severe right leg pain characterized as constant, deep and sharp, which is exacerbated by touch or movement. She rated her pain as an 8 on a scale of 1-10 most of the time, but a 10 out of 10 when it’s exacerbated. Other complaints included right upper extremity pain, imbalance, dizziness, severe head pain, insomnolence, and severe depression. She managed pain with prescribed hydrocodone. Pain was recalcitrant to the chiropractic adjustment treatments previously attempted. Upon examination she displayed an antalgic gait with a shortened stance phase. Any active or passive movement of the right leg created extreme apprehension and pain for this patient. Her right pedal pulse was weak and thready. Her feet were cold and mildly edematous bilaterally. She had edema of the right lower leg. Computerized dynamic posturography (CDP) testing showed a stability score of 76 with eyes closed. Videonystagmography (VNG) testing showed an inability to hold gaze in all directions as well as square wave jerks on leftward pursuits and rightward saccade step phase. Methods: She was treated for five days with specific brain based functional neurology strategies that included complex passive movements of upper and lower extremities, gaze stabilization eye exercises, trigeminal and hypoglossal stimulations, and whole-body off-vertical axis rotation. Results: Full and painless movement was restored in all limbs. She rated her right leg pain as a 1 out of 10. Symptoms of dizziness, insomnolence and depression were also resolved. Her gait returned to normal. CDP showed an increased stability score of 92 with eyes closed. Square wave jerks and other eye movement aberrations were markedly diminished on VNG testing. Conclusion: The positive outcomes in this case warrant further research of functional neurological treatments for patients suffering from chronic pain symptoms. Keywords: Chronic Pain Management, Dizziness, Functional Neurology, Depression, Chiropractic Conference: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration, Orlando, Florida, United States, 10 Dec - 14 Dec, 2015. Presentation Type: Poster Presentation Topic: Case Reports for Poster Presentation Citation: Esposito S, Jordan J and Mullin Elkins L (2015). BRAIN-BASED TREATMENT OF CHRONIC LEG PAIN AND IMBALANCE IN A MIDDLE-AGED FEMALE.. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration. doi: 10.3389/conf.fneur.2015.58.00028 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 01 Nov 2015; Published Online: 02 Nov 2015. * Correspondence: Dr. Susan Esposito, Life University, Marietta, Georgia, 30060, United States, susan.esposito@life.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Susan Esposito Julie Jordan Linda Mullin Elkins Google Susan Esposito Julie Jordan Linda Mullin Elkins Google Scholar Susan Esposito Julie Jordan Linda Mullin Elkins PubMed Susan Esposito Julie Jordan Linda Mullin Elkins Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Off-Vertical Axis Rotational Assessment of Transdermal Scopolamine for Motion Sickness Prophylaxis

Abstract The objectives of this study were to evaluate transdermal scopolamine for motion sickness prophylaxis, and to evaluate off-vertical axis rotation (OVAR) as a laboratory model of motion sickness. This was a randomized, prospective, double-blind study design, set in a vestibular research laboratory. The experimental subjects consisted of 12 patients – 7 male, 5 female – ages 21 to 57, with normal auditory/vestibular function. The intervention was off-vertical axis rotation 20 degrees in the dark after administration of transdermal scopolamine or placebo. The main outcome measures were time duration of tolerated off-vertical rotation, and subjective symptom reporting during rotation at one-minute intervals on a 0–4 scale. Results were as follows: patients treated with transdermal scopolamine had statistically significant improved tolerance time to off-vertical axis rotation. Reported symptom-atology on the 0–4 subjective symptom scale was significantly improved, as compared to placebo, and was dose-dependent. Conclusions are as follows: off-vertical axis rotation is a useful modality for the evaluation of motion sickness medications. Transdermal scopolamine showed statistically significant dose-dependent effects in mitigating OVAR-induced motion sickness symptomatology and was well tolerated.

Dynamic characteristics of otolith ocular response during counter rotation about dual yaw axes in mice

The central vestibular system plays an important role in higher neural functions such as self-motion perception and spatial orientation. Its ability to store head angular velocity is called velocity storage mechanism (VSM), which has been thoroughly investigated across a wide range of species. However, little is known about the mouse VSM, because the mouse lacks typical ocular responses such as optokinetic after nystagmus or a dominant time constant of vestibulo-ocular reflex for which the VSM is critical. Experiments were conducted to examine the otolith-driven eye movements related to the VSM and verify its characteristics in mice. We used a novel approach to generate a similar rotating vector as a traditional off-vertical axis rotation (OVAR) but with a larger resultant gravito-inertial force (>1g) by using counter rotation centrifugation. Similar to results previously described in other animals during OVAR, two components of eye movements were induced, i.e. a sinusoidal modulatory eye movement (modulation component) on which a unidirectional nystagmus (bias component) was superimposed. Each response is considered to derive from different mechanisms; modulations arise predominantly through linear vestibulo-ocular reflex, whereas for the bias, the VSM is responsible. Data indicate that the mouse also has a well-developed vestibular system through otoliths inputs, showing its highly conserved nature across mammalian species. On the other hand, to reach a plateau state of bias, a higher frequency rotation or a larger gravito-inertial force was considered to be necessary than other larger animals. Compared with modulation, the bias had a more variable profile, suggesting an inherent complexity of higher-order neural processes in the brain. Our data provide the basis for further study of the central vestibular system in mice, however, the underlying individual variability should be taken into consideration.

Is there a relationship between odors and motion sickness?

The aim of this study was to evaluate the relationship between olfaction and motion sickness. A sample of 18 participants was recruited and submitted to three sessions of nauseogenic stimulations: off vertical axis rotation (OVAR), performed under conditions of olfactory stimulation with limonene (pleasant odor), petrol (unpleasant odor) or distilled water (as a control). Motion sickness was assessed before, during and after each OVAR session. In addition, participants were asked to evaluate the intensity and hedonic valence of four odors (geraniol, limonene, butanol, petrol) as well as distilled water (as a control) before and after each OVAR session. Our analysis showed that OVAR has consistently increased the induced-motion sickness. However the addition of an odor that is pleasant or unpleasant during the rotation did not affect the occurrence of motion sickness symptoms compared to the control condition. Our results also showed that intensity of odors was significantly increased after OVAR and the intensity was significantly higher for unpleasant odors than for pleasant one. For the hedonicity, OVAR made unpleasant odors more unpleasant (p<0.0001) while it made limonene odor slightly more pleasant (p<0.05). The present study highlighted the lack of influence of odors in motion-induced sickness but an impact of a nauseogenic test on olfactory perception.

Otolith signals contribute to inter-individual differences in the perception of gravity-centered space

The aim of the present study was to investigate (1) the relative contribution of the egocentric reference as well as body orientation perception to visual horizon percept during tilt or during increased gravito-inertial acceleration (GiA, hypergravity environment) conditions and (2) the role of vestibular signals in the inter-individual differences observed in these perceptual modalities. Perceptual estimates analysis showed that backward tilt induced (1) an elevation of the visual horizon, (2) an elevation of the egocentric estimation (visual straight ahead) and (3) an overestimation of body tilt. The increase in the magnitude of GiA induced (1) a lowering of the apparent horizon, (2) a lowering of the straight ahead and (3) a perception of backward tilt. Overall, visual horizon percept can be expressed as the combination of body orientation perception and egocentric estimation. When assessing otolith reactivity using off-vertical axis rotation (OVAR), only visual egocentric estimation was significantly correlated with horizontal OVAR performance. On the one hand, we found a correlation between a low modulation amplitude of the otolith responses and straight ahead accuracy when the head axis was tilted relative to gravity. On the other hand, the bias of otolith responses was significantly correlated with straight ahead accuracy when subjects were submitted to an increase in the GiA. Thus, straight ahead sense would be dependent to some extent to otolith function. These results are discussed in terms of the contribution of otolith inputs in the overall multimodal integration subtending spatial constancy.

Neural Representation of Orientation Relative to Gravity in the Macaque Cerebellum

A fundamental challenge for maintaining spatial orientation and interacting with the world is knowledge of our orientation relative to gravity, i.e., head tilt. Sensing gravity is complicated because of Einstein's equivalence principle, in which gravitational and translational accelerations are physically indistinguishable. Theory has proposed that this ambiguity is solved by tracking head tilt through multisensory integration. Here we identify a group of Purkinje cells in the caudal cerebellar vermis with responses that reflect an estimate of head tilt. These tilt-selective cells are complementary to translation-selective Purkinje cells, such that their population activities sum to the net gravitoinertial acceleration encoded by the otolith organs, as predicted by theory. These findings reflect the remarkable ability of the cerebellum for neural computation and provide quantitative evidence for a neural representation of gravity, whose calculation relies on long-postulated theoretical concepts such as internal models and Bayesian priors.

Evaluation of the vestibulo-ocular reflex using sinusoidal off-vertical axis rotation in patients with canal paresis

The vestibulo-ocular reflex (VOR) was studied to determine the utility of off-vertical axis rotation (OVAR) in evaluating vestibular function in patients with canal paresis (CP). Our goal was to determine whether there is any correlation between caloric responses and sinusoidal rotatory responses. Subjects were rotated in a sinusoidal pattern with eyes open in complete darkness. Frequencies of 0.4 and 0.8Hz with a maximum angular velocity of 60°/s at either earth-vertical axis rotation (EVAR) or OVAR were used. Twenty-three control subjects and 21 patients with CP were investigated. Results showed that (1) the VOR gain difference between EVAR and OVAR in the CP patients was not significant at 0.4Hz and at 0.8Hz; (2) the gain during 0.4Hz EVAR was less in the bilateral CP patients compared to controls; and (3) the VOR gain of the affected side at 0.8Hz was significantly less during OVAR than during EVAR. We concluded that the absence or reduction of caloric responses does not indicate the absence of vestibular function. In addition, separation analysis of the VOR gain of affected and intact sides is useful for evaluating laterality of otolith function in patients with CP.

Eye movements and motion perception during off-vertical axis rotation after spaceflight1

Constant velocity off-vertical axis rotation (OVAR) provides dynamic linear acceleration stimuli that can be used to assess otolith function. Eight astronauts were rotated in darkness about their longitudinal axis 20° off vertical at low (0.125 Hz) and high (0.5 Hz) frequencies and their responses were compared before and after spaceflight. Eye movements were recorded using infrared videography and perceived motion was evaluated using a joystick with four degrees of freedom - pitch and roll tilt, front-back and lateral translation. Low-frequency OVAR generates tilt otolith-induced responses - modulation of ocular counter-roll and counter-pitch with perceived conical motion path - whereas high-frequency OVAR generates translational otolith-induced responses - modulation of horizontal and vergence slow phase velocity with perceived cylindrical motion path. While there were transient changes in the amplitude of the translational ocular responses on landing day, there were no major changes in the tilt ocular reflexes after adaptation to weightlessness. However, there was an increase in sensitivity to motion perception after spaceflight. Direct comparisons of pre- and postflight stimuli suggested that OVAR on landing day was less provocative of motion sickness than before spaceflight. These results confirm that some otolith reflexes elicited during passive motion may not be altered by short-duration spaceflight - or may readapt very quickly - and that the resolution of sensory conflict associated with postflight recovery involves higher-order neural processes.

Visual-vestibular stimulation influences spatial and non-spatial cognitive processing

This study investigated the impact of visual-vestibular stimulation on performance of an auditory information processing task in young and older adults. Performance on a spatial choice reaction time task was compared to performance on a non-spatial choice reaction time task. The tasks were performed during simultaneous rotational and moving visual stimulation. The non-spatial task was an auditory frequency discrimination task while the spatial task was a right-left lateralization task. Visual and vestibular conditions consisted of a non-movement baseline, sinusoidal earth-vertical axis rotation (EVAR) in darkness, off-vertical axis rotation (OVAR) in darkness at a constant velocity, OVAR in darkness with a sinusoidal profile, EVAR with a lighted visual surround, constant velocity optokinetic stimulation, and sinusoidal optokinetic stimulation. Baseline reaction times were subtracted from reaction times during each stimulus condition to yield "task cost", which was analyzed statistically. Subjects were healthy young (n=20; 24 ± 2.7 yrs; 10F) and older (n=29; 73 ± 6.0 yrs; 18F) adults. Results indicated that task cost was affected by the visual-vestibular condition and a task x condition interaction. There was no main effect of task or age group and no significant interaction with age. Otolithic stimulation and visual stimulation were associated with greater task cost compared to semicircular canal stimulation. Combining semicircular canal with otolithic or visual stimulation had no additional effect beyond otolithic or visual stimulation alone. This pattern of task cost being larger for otolith or visual vs. semicircular canal stimulation was found for both the spatial and non-spatial tasks. The significant interaction between condition and task type revealed that the task cost for the spatial task was larger than the task cost for the non-spatial task during visual conditions but not during non-visual conditions although the visual and non-visual conditions were not entirely comparable. This study suggests that interference of vestibular stimulation with cognitive processing is especially prominent for otolithic and visual stimulation although the strength of the various visual-vestibular stimuli may not have been uniform. Also, spatial tasks are more affected than non-spatial tasks during visual stimulation and interference between vestibular stimulation and cognitive processing is not age dependent for these relatively easy tasks.

Sensory conflict compared in microgravity, artificial gravity, motion sickness, and vestibular disorders.

Perceptual disturbances and motion sickness are often attributed to sensory conflict. We investigated several conditions: head movements in microgravity, periodic motions in 1-g, and locomotion with vestibular disorders. In every case, linear vectors such as linear and gravitational acceleration are crucial factors, as previously found for head movements in artificial gravity, and thus the importance of measuring linear vectors emerges as a common theme. By modeling the sensory conflict between the vestibular and somatosensory systems, we computed a measure of linear conflict known as the "Stretch Factor". We hypothesized that the motions with the greatest Stretch Factor would be the most provocative motions. For head movements in microgravity, the Stretch Factor can explain why fast movements are more provocative than slow movements, and why pitch movements are more provocative than yaw movements. For off-vertical-axis rotation (OVAR) in 1-g, the Stretch Factor predicts that the most provocative frequency is higher than that for vertical linear oscillation (VLO). For example, the same sensor dynamics can predict a most provocative frequency around 0.2 Hz for VLO but 0.3 Hz for OVAR, solving a mystery of this experimentally observed discrepancy. Finally, we determined that certain sensory conflict perceptions reported by vestibular patients could be explained via mathematical simulation.

Motion Sickness Treatment Analysis with OVAR

Objective: Evaluation of transdermal scopolamine for motion sickness prophylaxis. Method: Randomized, prospective double blind. 2010-11. Twelve patients, 7 male, 5 female, ages 21 to 57. Intervention(s): Off-vertical axis rotation 20° in the dark after administration of transdermal scopolamine or placebo. Outcome measures: Duration of tolerated off-vertical rotation; subjective symptom reporting at 1-minute intervals on a 0 to 4 scale. Results: Patients treated with transdermal scopolamine had statistically significant improved tolerance time to off-vertical axis rotation. Reported symptomatology on the 0-3 subjective symptom scale was significantly improved as compared to placebo and was dose-dependent. These results were significant to the .05 confidence level. Conclusion: Off-vertical axis rotation is a useful modality for the evaluation of motion sickness medications. Transdermal scopolamine showed statistically significant dose-dependent effects in mitigating OVAR-induced motion sickness symptomatology and was well tolerated.

Off Vertical Axis Rotation Motion Sickness and Field Dependence

Our study probed the relationship between field dependence and the development of nausea in light and dark during whole-body, off vertical axis rotation (OVAR). There were 24 subjects who underwent OVAR at 0.2 Hz, 18 degree tilt. Exposures were undertaken in both light and darkness in sessions spaced 5 d apart in balanced order design. During rotation, nausea was rated at 1-min intervals to a cut off at 20 min or a level of 'moderate nausea' was attained, at which point motion stopped. Before and after OVAR sessions field dependence was rated with the rod and frame test (RFT) with head upright or tilted 28 degree to induce a head-centric bias. Subjects tolerated OVAR longer in the light (mean 13.3 min +/- 6.8 SD) than in darkness (11.1 min +/- 7.2). Motion sickness susceptibility evaluated by questionnaire was inversely correlated with tolerance of OVAR in the light. There was a tendency for subjects who were visual field dependent to fare better with OVAR in the light than in darkness. Subjects whose RFT estimates with head tilted tended to incline the visual vertical to the direction of head tilt better tolerated OVAR in darkness. The results suggest that susceptibility, as evaluated by questionnaires probing motion sickness experiences in daily life, is influenced by visual factors. Assessments of sensitivity to reference frames for orientation, either visual or ego-centered, show promise for markers of motion sickness susceptibility according to the visual surround rather than to absolute levels of susceptibility to motion sickness.

Differences between perception and eye movements during complex motions

During passive whole-body motion in the dark, the motion perceived by subjects may or may not be veridical. Either way, reflexive eye movements are typically compensatory for the perceived motion. However, studies are discovering that for certain motions, the perceived motion and eye movements are incompatible. The incompatibility has not been explained by basic differences in gain or time constants of decay. This paper uses three-dimensional modeling to investigate gondola centrifugation (with a tilting carriage) and off-vertical axis rotation. The first goal was to determine whether known differences between perceived motions and eye movements are true differences when all three-dimensional combinations of angular and linear components are considered. The second goal was to identify the likely areas of processing in which perceived motions match or differ from eye movements, whether in angular components, linear components and/or dynamics. The results were that perceived motions are more compatible with eye movements in three dimensions than the one-dimensional components indicate, and that they differ more in their linear than their angular components. In addition, while eye movements are consistent with linear filtering processes, perceived motion has dynamics that cannot be explained by basic differences in time constants, filtering, or standard GIF-resolution processes.

Cerebral blood flow decreases prior to nausea during off-vertical axis rotation

Cerebral blood flow decreases prior to nausea during off-vertical axis rotation

Cerebral Blood Flow Regulation: Role of Otolith Inputs

Recent data has implicated a role for the vestibular system in maintaining blood pressure and cerebral blood flow (CBF). Through off vertical axis rotation (OVAR), we activated the otolith organs in 21 healthy subjects to determine their effect on CBF. Subjects rotated off vertical at 20° to a constant velocity in darkness at three frequencies (0.03125, 0.125 and 0.5 Hz) and three head directions (yaw angle: 0°, 40° left/right). CBF (transcranial Doppler), blood pressure (Portapres), and end tidal CO2 (Puritan Bennet) were measured continuously. CBF exhibited sinusoidal patterns (±2.7% at 0.03125; ±4.3% at 0.125; ±0.4% at 0.5 Hz) as did blood pressure (±5.1 mmHg at 0.03125; ±3.2 mmHg at 0.125; ±7.9 mmHg at 0.5Hz) which occurred as a function of frequency. Changing fixed head direction resulted in a phase shift in the associated CBF signal, but had negligible effects on blood pressure. Data indicate that by changing otolith position by moving to a leftward or rightward yaw of 40°, similar phase shifts occurred in CBF. Since trunk position remained unchanged, these data suggest that oscillations in CBF associated with OVAR are primarily due to otolith stimulation. Work supported by NIH NIDCD and NASA.

Preservation of vestibular function after scala vestibuli cochlear implantation

A 58-year-old man, in whom the cochlear implant (CI) had been inserted into the left ear, had right middle-ear cancer. The CI was removed immediately before receiving subtotal removal of right temporal bone. Four months later, the CI was again inserted in his left cochlea. Because of obliterated scala tympani, the 22 active electrodes of the CI were placed into the scala vestibuli. After the surgery, the patient complained that he experienced rotary vertigo and "jumbling of vertical direction" of objects on walking. Using rotation test, we evaluated vestibular function of remaining left ear. Numerous horizontal nystagmus beats were induced during earth-vertical axis rotation, whereas vertical downbeat nystagmus was scarcely induced during off-vertical axis rotation. The horizontal vestibulo-ocular reflex (VOR) was almost normally induced by sinusoidal stimulation at 0.8Hz. These data suggest that the scala vestibuli insertion of CI would be not so invasive against the lateral semicircular canal.

Prolonged reduction of motion sickness sensitivity by visual-vestibular interaction

The angular vestibulo-ocular reflex (aVOR) and optokinetic nystagmus (OKN) were elicited simultaneously at low frequencies to study effects of habituation of the velocity storage time constant in the vestibular system on motion sickness. Twenty-nine subjects, eleven of whom were susceptible to motion sickness from common transportation, were habituated by sinusoidal rotation at 0.017 Hz at peak velocities from 5 to 20°/s, while they watched a full-field OKN stimulus. The OKN stripes rotated in the same direction and at the same frequency as the subjects, but at a higher velocity. This produced an OKN opposite in direction to the aVOR response. Motion sickness sensitivity was evaluated with off-vertical axis rotation (OVAR) and by the response to transportation before and after 5 days of visual-vestibular habituation. Habituation did not induce motion sickness or change the aVOR gains, but it shortened the vestibular time constants in all subjects. This greatly reduced motion sickness produced by OVAR and sensitivity to common transport in the motion susceptible subjects, which persisted for up to 18 weeks. Two motion susceptible subjects who only had aVOR/OKN habituation without being tested with OVAR also became asymptomatic. Normal subjects who were not habituated had no reduction in either their aVOR time constants or motion sickness sensitivity. The opposing aVOR/OKN stimulation, which has not been studied before, was well tolerated, and for the first time was an effective technique for rapid and prolonged habituation of motion sickness without exposure to drugs or other nauseating habituation stimuli.

Rotational Test, Off-vertical Axis Rotation

Since our visual sense performs analysis best when images remain steady on the retina, the eyes need to move. To move the eyes, optokinetic and vestibular reflexes have evolved to stabilize images on the retina during head movements. The vestibular and optokinetic systems work together to maintain clear vision during head movements. Because natural head movements are of high frequency, the visual system is impeded by relatively slow retinal processing (about 70 msec), and cannot act rapidly enough to produce compensatory eye movements that can hold images steady on the retina. In contrast, the semicircular-ocular reflex (ScOR) has a latency of less than 16 msec. The ScOR promptly produces slow phase eye movements to compensate for head rotations. To evaluate the ScOR, caloric and rotational tests are routinely used. Barany first described the velocity step test in 1907. In 1948, Van Egmond et al. described an elaboration of this test, which they called cupulometry. These tests are rarely performed today. They have proved to be highly unreliable and not sensitive enough in the detection of lesions, because of the difficulty in producing repeatable stimuli and making accurate response measurements. The modern era of rotational testing began in the 1960s. Today all aspects of rotational testing including stimulus generation, response measurement, and data analysis are controlled by computer. The vestibular system also contains otolithic receptors that respond to linear accelerations of the head. The otolith-ocular reflex (OOR) becomes important when head translations cause a slip in the image on the retina. Off-vertical axis rotation (OVAR) is a stimulus wherein persons are rotated while the axis about which they are rotating is tilted with respect to gravity. Thus the OVAR can be used to assess the OOR. In this article, the principle and clinical application of rotational tests are introduced.