Optokinetic Nystagmus Responses Research Articles

Nystagmus Associated With the Absence of MYOD Expression Across the Lifespan in Extraocular and Limb Muscles.

The extraocular muscles (EOMs) undergo significant levels of continuous myonuclear turnover and myofiber remodeling throughout life, in contrast to limb skeletal muscles. Activation of the myogenic pathway in muscle precursor cells is controlled by myogenic transcription factors, such as MYOD. Limb muscles from MyoD-/- mice develop normally but have a regeneration defect, and these mice develop nystagmus. We examined MyoD-/- mice to determine if they have an aging phenotype. Eye movements of aging MyoD-/- mice and littermate controls (wild type) were examined using optokinetic nystagmus (OKN). We assessed limb muscle function, changes to myofiber number, mean cross-sectional area, and abundance of the PAX7 and PITX2 populations of myogenic precursor cells. Aging did not significantly affect limb muscle function despite decreased mean cross-sectional areas at 18+months. Aging wild type mice had normal OKN responses; all aging MyoD-/- mice had nystagmus. With OKN stimulus present, the MyoD-/- mice at all ages had shorter slow phase durations compared to wild type age matched controls. In the dark, the MyoD-/- mice had a shorter slow phase duration with age. This correlated with significantly decreased fiber numbers and cross-sectional areas. The EOM in MyoD-/- mice had increased numbers of PAX7-positive satellite cells and significantly decreased PITX2-positive myonuclei. The absence of MYOD expression in aging mice causes a decrease in on-going myofiber remodeling, EOM fiber size, and number, and is associated with the development of spontaneous nystagmus. These results suggest that muscle-specific mutations can result in nystagmus, with increasing aging-related changes in the MyoD-/- EOM.

カルバマゼピン中毒により下眼瞼向き眼振を認めた薬剤性めまい症例

We report the case of a 33-year-old man who presented with disequilibrium and downbeat nystagmus. Balance testing showed failure of visual suppression of caloric nystagmus with insufficient optokinetic nystagmus responses, suggesting central vestibular dysfunction. However, MRI showed no lesions in the brain, including in the cerebellum. The patient had been diagnosed previously as having epilepsy, and the convulsions had remained under control for more than 10 years with a maintenance dose of carbamazepine (900mg/day). Blood tests revealed a serum level of carbamazepine of 10.7mEq/l, which was over the therapeutic range (4.0-10.0mEq/l). Therefore, his carbamazepine dose was reduced, and with a reduction of the dose to 600mg/day, his disequilibrium and downbeat nystagmus gradually disappeared, along with a decrease in return of the serum level of carbamazepine to the therapeutic range. Therefore, we diagnosed the disequilibrium with downbeat nystagmus in this patient as having been caused by carbamazepine intoxication. Although carbamazepine is metabolized by CYP3A4 in the liver, elevated levels of the drug have been reported in cases of renal failure. As he also suffered from polycystic kidneys, we consider that the progressive renal dysfunction in our patient could have precipitated the carbamazepine intoxication.

Parameters of Optokinetic Nystagmus Are Influenced by the Nature of a Visual Stimulus

Studies on contrast sensitivity (CS) testing using optokinetic nystagmus (OKN) proposed adjusting the stimulus presentation duration based on its contrast, to increase the time efficiency of such measurement. Furthermore, stimulus-specific limits of the least OKN gain might reduce false negatives in OKN detection procedures. Therefore, we aimed to test the effects of various stimulus characteristics on OKN and to propose the stimulus-specific limits for the OKN gain and stimulus presentation duration. We tested the effect of contrast (C), spatial frequency (SF), and color on selected parameters of robust OKN response, namely its onset and offset time, amplitude, and gain. The right eyes of fifteen emmetropes were tracked with an infrared eye tracker during monocular observations of sinusoidal gratings moving over the horizontal plane with a velocity of (21∘/s). The available contrast levels were C: 0.5%, 2.0%, 8.2%, 16.5%, 33.0%, and 55.5% presented in a random order for ten times in all measurements of SF: 0.12, 0.25, 0.5, and 1.00 cycles per degree and grating type: luminance, red-green, and blue-yellow. This study showed a significant effect of the stimulus characteristics on the OKN onset, offset and gain. The effect of SF was insignificant in OKN amplitude; however, it indicated significance for the C and grating type. Furthermore, the OKN gain and offset limits were proposed as functions of contrast for the luminance and chromatic gratings. This study concludes the characteristics of a visual stimulus have an effect on the OKN gain and onset and offset time, yet do not affect the eye-movement amplitude considerably. Moreover, the proposed limits are expected to improve the time efficiency and eye-movement detection in OKN-based contrast sensitivity measurements.

A New Optokinetic Testing Method to Measure Rat Vision.

Optokinetic nystagmus (OKN) is a reflexive eye movement initiated by the motion of visual stimuli in the field of vision. The head-tracking movement associated with OKN is commonly used as a measure of visual function in rodents. To record OKN responses in normal and experimental rats, a simple and inexpensive apparatus has been developed. This setup uses two tablet screens to display the OKN visual stimulus consisting of high contrast black and white stripes generated using the OKN Stripes Visualization Web Application, a freely available software. The rat is placed inside a clear Plexiglass holder that limitsmovement so that therat's head continuously faces the OKN display screen. The position of the rat holder can be changed to adjust the distance between the rat and the display screen. A micro-camera positioned above the rat holder is used to record the rat's visual activities. These recordings can be used for quantitative assessments. Based on the presence or absence of clear head-tracking, the OKN responses at different spatial frequencies can be determined. The collected data demonstrates a novel technique for reliable measurement of visual acuity in normal and retinal degenerate rats.

Contrast Sensitivity Testing in Healthy and Blurred Vision Conditions Using a Novel Optokinetic Nystagmus Live-Detection Method

PurposeThe aim of the current study was to develop and validate an automated contrast sensitivity (CS) test using a live- detection of optokinetic nystagmus (OKN) and an adaptive psychometric procedure. In addition, the study sought to replicate the known effect of defocus on CS for the OKN-based measurements in emmetropic participants.MethodsFifteen participants viewed a horizontally moving grating while their eyes were tracked with an infra-red (IR) eye-tracker. To simulate the clinical conditions of the CS measurements, the participants were stimulated monocularly as the left eye was occluded by an IR filter. The horizontal eye position was continuously analyzed for OKN responses, and the stimulus contrast was changed by an adaptive psychometric method depending on the outcome. Furthermore, the newly proposed OKN live-detection was verified against an offline analysis and an expert-observer judgement. The OKN-based CS was measured for six spatial frequencies at normal vision and three levels of defocus using spherical convex lenses.ResultsThe newly proposed OKN live-detection method showed a sufficient detection performance for implementation of adaptive procedures, and the detection rate is similar or better compared to offline detection methods. Spatial frequency and defocus had a significant effect on the OKN-based CS (P < 0.0001 for both).ConclusionsThe current study presents a novel method to measure motion CS in an automated way, combining the real-time detection of OKN and an adaptive psychometric procedure. Furthermore, the known effect of defocus on CS was successfully replicated with the newly developed tool.Translational RelevanceOKN-based CS is a novel approach to assess spatial vision, which is sensitive to subtle effects of defocus, allowing use with nonverbal patients and infants. Furthermore, the newly developed tool may improve the performance of such measurements.

Visual acuity in the flying snake, Chrysopelea paradisi.

Visual control during high-speed aerial locomotion requires a visual system adapted for such behaviors. Flying snakes (genus: Chrysopelea) are capable of gliding at speeds up to 11 m s-1 and perform visual assessments before take-off. Determining nuances of control requires a closed-loop experimental system, such as immersive virtual arenas. To characterize vision in the flying snake Chrysopelea paradisi, we used digitally reconstructed models of the head to determine a 3D field of vision. We also used optokinetic drum experiments and compared slowphase optokinetic nystagmus (OKN) speeds to calculate visual acuity and conducted preliminary experiments to determine whether snakes would respond to closed-loop virtual stimuli. Visual characterization showed that C. paradisi likely has a large field of view (308.5 ± 6.5° azimuthal range), with a considerable binocular region (33.0 ± 11.0° azimuthal width) that extends overhead. Their visual systems are broadly tuned and motion-sensitive, with peak OKN response gains of 0.50 ± 0.11 seen at 46.06 ± 11.08 Hz, and a low spatial acuity, with peak gain of 0.92 ± 0.41 seen at 2.89 ± 0.16 cpd (cycles per degree). These characteristics were used to inform settings in an immersive virtual arena, including framerate, brightness, and stimulus size. In turn, the immersive virtual arena was used to reproduce the optokinetic drum experiments. We elicited OKN in open-loop experiments, with a mean gain of 0.21 ± 0.9 seen at 0.019 ± 6x10-5 cpd and 1.79 ± 0.01 Hz. In closed-loop experiments, snakes did not exhibit OKN, but held the image fixed, indicating visual stabilization. These results demonstrate for that C. paradisi responds to visual stimuli in a digital virtual arena. The accessibility and adaptability of the virtual setup make it suitable for future studies of visual control in snakes and other animals in an unconstrained setting.

Right frontal eye field has perceptual and oculomotor functions during optokinetic stimulation and nystagmus.

The right frontal eye field (rFEF) is associated with visual perception and eye movements. rFEF is activated during optokinetic nystagmus (OKN), a reflex that moves the eye in response to visual motion (optokinetic stimulation, OKS). It remains unclear whether rFEF plays causal perceptual and/or oculomotor roles during OKS and OKN. To test this, participants viewed a leftward-moving visual scene of vertical bars and judged whether a flashed dot was moving. Single pulses of transcranial magnetic stimulation (TMS) were applied to rFEF on half of trials. In half of blocks, to explore oculomotor control, participants performed an OKN in response to the OKS. rFEF TMS, during OKN, made participants more accurate on trials when the dot was still, and it slowed eye movements. In separate blocks, participants fixated during OKS. This not only controlled for eye movements but also allowed the use of EEG to explore the FEF's role in visual motion discrimination. In these blocks, by contrast, leftward dot motion discrimination was impaired, associated with a disruption of the frontal-posterior balance in alpha-band oscillations. None of these effects occurred in a control site (M1) experiment. These results demonstrate multiple related yet dissociable causal roles of the right FEF during optokinetic stimulation.NEW & NOTEWORTHY This study demonstrates causal roles of the right frontal eye field (FEF) in motion discrimination and eye movement control during visual scene motion: previous work had only examined other stimuli and eye movements such as saccades. Using combined transcranial magnetic stimulation and EEG and a novel optokinetic stimulation motion-discrimination task, we find evidence for multiple related yet dissociable causal roles within the FEF: perceptual processing during optokinetic stimulation, generation of the optokinetic nystagmus, and the maintenance of alpha oscillations.

Visual Target Strategies in Infantile Nystagmus Patients With Horizontal Jerk Waveform.

The aim of this study was to propose a new pathophysiological hypothesis for involuntary eye oscillation in infantile nystagmus (IN): patients with IN exhibit impaired gaze fixation, horizontal smooth pursuit and optokinetic nystagmus (OKN) and use saccadic eye movements for these underlying impairments. In order to induce saccades, they make enough angle between gaze and target by precedent exponential slow eye movements. IN consists of the alternate appearance of the saccade and the slow eye movements. Unlike most previous theories, IN is therefore considered a necessary strategy allowing for better vision and not an obstacle to clear vision. In five patients with IN, eye movements were analyzed during the smooth pursuit test, saccadic eye movement test, OKN test and vestibulo-ocular reflex (VOR) test. Their gaze fixation, horizontal smooth pursuit, OKN and the last half of the slow phase of VOR were impaired. The lines obtained by connection of the end eye positions of fast phase of nystagmus coincided with the trajectories of targets. The findings indicate that patients followed the target by the fast but not the slow phase of nystagmus, which supports our hypothesis. By setting the direction of slow phase of nystagmus opposite to the direction of the OKN stimulation, enough angle can be effectively made between the gaze and target for the induction of saccade. This is the mechanism of reversed OKN response. In darkness and when eyes are closed, IN weakens because there is no visual target and neither the saccade for catching up the target or slow phase for induction of the saccade is needed.

Global motion perception is associated with motor function in 2-year-old children

The dorsal visual processing stream that includes V1, motion sensitive area V5 and the posterior parietal lobe, supports visually guided motor function. Two recent studies have reported associations between global motion perception, a behavioural measure of processing in V5, and motor function in pre-school and school aged children. This indicates a relationship between visual and motor development and also supports the use of global motion perception to assess overall dorsal stream function in studies of human neurodevelopment. We investigated whether associations between vision and motor function were present at 2 years of age, a substantially earlier stage of development. The Bayley III test of Infant and Toddler Development and measures of vision including visual acuity (Cardiff Acuity Cards), stereopsis (Lang stereotest) and global motion perception were attempted in 404 2-year-old children (±4 weeks). Global motion perception (quantified as a motion coherence threshold) was assessed by observing optokinetic nystagmus in response to random dot kinematograms of varying coherence. Linear regression revealed that global motion perception was modestly, but statistically significantly associated with Bayley III composite motor (r2=0.06, P<0.001, n=375) and gross motor scores (r2=0.06, p<0.001, n=375). The associations remained significant when language score was included in the regression model. In addition, when language score was included in the model, stereopsis was significantly associated with composite motor and fine motor scores, but unaided visual acuity was not statistically significantly associated with any of the motor scores. These results demonstrate that global motion perception and binocular vision are associated with motor function at an early stage of development. Global motion perception can be used as a partial measure of dorsal stream function from early childhood.

Threat effects on human oculo-motor function

Neuro-anatomical evidence supports the potential for threat-related factors, such as fear, anxiety and vigilance, to influence brainstem motor nuclei controlling eye movements, as well as the vestibular nuclei. However, little is known about how threat influences human ocular responses, such as eye saccades (ES), smooth pursuit eye tracking (SP), and optokinetic nystagmus (OKN), and whether these responses can be facilitated above normal baseline levels with a natural source of threat. This study was designed to examine the effects of height-induced postural threat on the gain of ES, SP and OKN responses in humans. Twenty participants stood at two different surface heights while performing ES (ranging from 8° to 45° from center), SP (15, 20, 30°/s) and OKN (15, 30, 60°/s) responses in the horizontal plane. Height did not significantly increase the slope of the relationship between ES peak velocity and initial amplitude, or the gain of ES amplitude. In contrast height significantly increased SP and OKN gain. Significant correlations were found between changes in physiological arousal and OKN gain. Observations of changes with height in OKN and SP support neuro-anatomical evidence of threat-related mechanisms influencing both oculo-motor nuclei and vestibular reflex pathways. Although further study is warranted, the findings suggest that potential influences of fear, anxiety and arousal/alertness should be accounted for, or controlled, during clinical vestibular and oculo-motor testing.

Cisplatin-induced toxicity decreases the mouse vestibulo-ocular reflex

Cisplatin is a chemotherapeutic agent commonly used for the treatment of solid tumors, and its side-effects include vestibulotoxicity. Previous studies have reported cisplatin-induced vestibulotoxicity in various animal models, but no study has investigated in vivo mouse vestibular dysfunction after cisplatin. The aim of this study was to investigate cisplatin-induced vestibulotoxicity in C57BL/6J mice. Vestibular function was assessed by recording the vestibulo-ocular reflex (VOR). This was done during sinusoidal rotations in the horizontal plane at three frequencies (0.5, 1.0 and 2.5Hz). A high-resolution, high-frequency digital infra-red camera was used with eye-tracking algorithms. Cisplatin at 16mg/kg, but not 8mg/kg, decreased the VOR gain at 2.5Hz compared with the vehicle control. Following 16mg/kg cisplatin treatment, the animals showed no change in the optokinetic nystagmus response, suggesting that no major changes in visual or oculomotor functions had occurred. This mouse model may be useful for studying cisplatin-induced vestibulotoxicity and its treatment.

Divided visual attention: A comparison of patients with multiple sclerosis and controls, assessed with an optokinetic nystagmus suppression task

Multiple sclerosis (MS) frequently causes impairment of cognitive function. We compared patients with MS with controls on divided visual attention tasks. The MS patients’ and controls’ stare optokinetic nystagmus (OKN) was recorded in response to a 24°/s full field stimulus. Suppression of the OKN response, judged by the gain, was measured during tasks dividing visual attention between the fixation target and a second stimulus, central or peripheral, static or dynamic. All participants completed the Audio Recorded Cognitive Screen. MS patients had lower gain on the baseline stare OKN. OKN suppression in divided attention tasks was the same in MS patients as in controls but in both groups was better maintained in static than in dynamic tasks. In only dynamic tasks, older age was associated with less effective OKN suppression. MS patients had lower scores on a timed attention task and on memory. There was no significant correlation between attention or memory and eye movement parameters. Attention, a complex multifaceted construct, has different neural combinations for each task. Despite impairments on some measures of attention, MS patients completed the divided visual attention tasks normally.

Infantile Nystagmus and Abnormalities of Conjugate Eye Movements in Down Syndrome.

Subjects with Down syndrome (DS) have an anatomical defect within the cerebellum that may impact downstream oculomotor areas. This study characterized gaze holding and gains for smooth pursuit, saccades, and optokinetic nystagmus (OKN) in DS children with infantile nystagmus (IN). Clinical data of 18 DS children with IN were reviewed retrospectively. Subjects with constant strabismus were excluded to remove any contribution of latent nystagmus. Gaze-holding, horizontal and vertical saccades to target steps, horizontal smooth pursuit of drifting targets, OKN in response to vertically or horizontally-oriented square wave gratings drifted at 15°/s, 30°/s, and 45°/s were recorded using binocular video-oculography. Seven subjects had additional optical coherence tomography imaging. Infantile nystagmus was associated with one or more gaze-holding instabilities (GHI) in each subject. The majority of subjects had a combination of conjugate horizontal jerk with constant or exponential slow-phase velocity, asymmetric or symmetric, and either monocular or binocular pendular nystagmus. Six of seven subjects had mild (Grade 0-1) persistence of retinal layers overlying the fovea, similar to that reported in DS children without nystagmus. All subjects had abnormal gains across one or more stimulus conditions (horizontal smooth pursuit, saccades, or OKN). Saccade velocities followed the main sequence. Down syndrome subjects with IN show a wide range of GHI and abnormalities of conjugate eye movements. We propose that these ocular motor abnormalities result from functional abnormalities of the cerebellum and/or downstream oculomotor circuits, perhaps due to extensive miswiring.

Up-down asymmetry in vertical vection

To investigate whether up-down asymmetry similar to that reported in vertical optokinetic nystagmus (OKN), that is, larger OKN responses for upward motion than for downward motion, would appear in vertical vection, we conducted three experiments. In all three experiments, participants viewed a vertically moving random-dot pattern. In Experiments 1 and 2, participants reported vection using a joystick. After each trial, they were also asked to rate the vection magnitude experienced during the stimulus presentation. In Experiment 3, eye movements and vection magnitude (rated after each trial) in response to the stimulus were measured. The results of Experiment 1 showed larger vection magnitude for the upward motion of the stimulus than for the downward motion of it. However, vection onset latency did not change much with stimulus motion direction. Experiment 2 revealed that the up-down asymmetry in vection manifested progressively during the latter part of the stimulus presentation period. Experiment 3 showed clear up-down asymmetry in both OKN and vection magnitude. These results not only indicate that up-down asymmetry similar to that reported in vertical OKN appears in vertical vection, but they also support the notion that the mechanisms underlying vection and OKN are closely related to each other.

Motion Information via the Nonfixating Eye Can Drive Optokinetic Nystagmus in Strabismus.

Strabismic patients can perceptually suppress information from one eye to avoid double vision. However, evidence from prior studies shows that some parts of the visual field of the deviated eye are not suppressed. Our goal here was to investigate whether motion information available only to the deviated eye can be utilized by the oculomotor system to drive eye movements. Binocular eye movements were acquired in two exotropic monkeys in a dichoptic viewing task in which the fixating eye viewed a stationary spot and the deviated eye viewed a 10° × 10° stationary patch that contained a drifting grating stimulus moving at 10°/s to the right or left for 20 seconds. Spatial location and contrast of the grating were systematically varied in subsequent trials. For each trial, mean slow-phase velocity of the optokinetic nystagmus (OKN) elicited by grating motion was calculated. We found that OKN responses can be elicited by a motion stimulus presented to the foveal region of the deviated eye. Optokinetic nystagmus magnitude varied depending on which eye was viewing the drifting grating and correlated well with fixation preference and fixation stability (indicators of amblyopia). The magnitude of OKN increased for increased relative contrast of the motion stimulus compared to the fixation spot. Our results show that motion information available only to the deviated eye can drive optokinetic eye movements. We conclude that the brain has access to visual information from portions of the deviated eye (including the fovea) in strabismus that it can use to drive eye movements.

POST-CONCUSSION DIZZINESS IMPROVES FROM MULTIMODAL NEUROREHABILITATION

Event Abstract Back to Event POST-CONCUSSION DIZZINESS IMPROVES FROM MULTIMODAL NEUROREHABILITATION Frederick R. Carrick1* and David J. Traster1* 1 Carrick Institute, United States Background: We describe an 18 year-old male who presents with headaches, dizziness, brain fog and nausea following multiple mild traumatic brain injuries sustained during athletics. Methods: Comprehensive neurologic examination demonstrated a Myerson’s/glabella sign, and a grade 2 hypomimia on the UPDRS scale. During oculomotor examination the patient had marked instability in eccentric gaze holding in all planes, bilateral saccadic pursuits horizontally, hypometric saccades in all planes, and minimal horizontal visual optokinetic nystagmus responses. The patient participated in a five day vestibular rehabilitation program that included off-vertical-axis-rotation vestibular rehabilitation, gaze stabilization exercises and repetitive peripheral somatosensory stimulation to ophthalmic, maxillary and mandibular distributions of the trigeminal nerve bilaterally. Results: The patient had a complete resolution of dizziness as well as improvements in mental clarity and nausea. Conclusion: The authors suggest further investigation into multimodal neurorehabilitaion in the management of mild traumatic brain injuries. Keywords: Dizziness, concussion, concussion rehabilitation, Traumatic brain injury (TBI), Neurorehabilitation, Nausea 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: Carrick FR and Traster DJ (2015). POST-CONCUSSION DIZZINESS IMPROVES FROM MULTIMODAL NEUROREHABILITATION. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration. doi: 10.3389/conf.fneur.2015.58.00088 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: 02 Sep 2015; Published Online: 02 Nov 2015. * Correspondence: Prof. Frederick R Carrick, Carrick Institute, Cape Canaveral, United States, drfrcarrick@post.harvard.edu Dr. David J Traster, Carrick Institute, Cape Canaveral, United States, dtraster3@gmail.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 Frederick R Carrick David J Traster Google Frederick R Carrick David J Traster Google Scholar Frederick R Carrick David J Traster PubMed Frederick R Carrick David J Traster 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.

REPETITIVE PERIPHERAL SOMATOSENSORY STIMULATION IMPROVES TRANSVERSE MYELITIS

Event Abstract Back to Event REPETITIVE PERIPHERAL SOMATOSENSORY STIMULATION IMPROVES TRANSVERSE MYELITIS Frederick R. Carrick1*, David J. Traster1*, Brian Sass1*, Chriss Sass1*, Elias Druckman2*, Andrew Funk2* and Jean Carlos Acevedo2* 1 Carrick Institute, United States 2 Life University, United States Background: A 57 year old female presents with the chief complaint of numbness, lack of motor control and loss of sensation bilaterally from the mid-trunk down to the feet. The symptoms started with a sudden overnight onset with no known cause or injury reported by patient. She had been wheelchair-bound since the onset of the anesthesia. Methods: After an in-depth neurological examination, the patient demonstrated a right hypertropia with a left head tilt. Onychomycosis was present bilaterally at the toes, more so on the right than on the left side. The patient demonstrated brisk reflexes bilaterally and a bilateral Babinski response with excessive withdrawal. Sensory testing revealed intact sensation above the level of the umbilicus, but the patient revealed bilateral anesthesia below the level of the umbilicus. Videonystagmography (VNG) analysis revealed a right-beating nystagmus with fixation removed in the dark. The patient also revealed a consistent right corectasia throughout the VNG analysis. Optokinetic nystagmus was poor in both the horizontal and vertical directions. A treatment plan involving repetitive stimulation using a repetitive peripheral somatosensory stimulation starting at level of T9 and applying inferiorly to the sacral plexus, as well as low-level laser at the dermatomal level of T9 paraspinally was applied. Results: After five days of rehabilitation the patient reported sensory gain on the trunk and lower extremities and regained normal visual optokinetic nystagmus responses. Conclusion: The authors suggest further investigation into comprehensive, multimodal forms of neurorehabilitation in the management of transverse myelitis. Keywords: Transverse myelitis, Neurorehabilitation, Physical rehabilitation, Electric Stimulation, transverse myelitis rehabilitation 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: Carrick FR, Traster DJ, Sass B, Sass C, Druckman E, Funk A and Acevedo J (2015). REPETITIVE PERIPHERAL SOMATOSENSORY STIMULATION IMPROVES TRANSVERSE MYELITIS. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration. doi: 10.3389/conf.fneur.2015.58.00112 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: 02 Sep 2015; Published Online: 02 Nov 2015. * Correspondence: Prof. Frederick R Carrick, Carrick Institute, Cape Canaveral, United States, drfrcarrick@post.harvard.edu Dr. David J Traster, Carrick Institute, Cape Canaveral, United States, dtraster3@gmail.com Dr. Brian Sass, Carrick Institute, Cape Canaveral, United States, sassbria@gmail.com Dr. Chriss Sass, Carrick Institute, Cape Canaveral, United States, sasschr1@gmail.com Mr. Elias Druckman, Life University, Marietta, United States, Drdruckman@gmail.com Dr. Andrew Funk, Life University, Marietta, United States, funkaj1981@yahoo.com Mr. Jean Carlos Acevedo, Life University, Marietta, United States, jeanacevedo@gmail.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 Frederick R Carrick David J Traster Brian Sass Chriss Sass Elias Druckman Andrew Funk Jean Carlos Acevedo Google Frederick R Carrick David J Traster Brian Sass Chriss Sass Elias Druckman Andrew Funk Jean Carlos Acevedo Google Scholar Frederick R Carrick David J Traster Brian Sass Chriss Sass Elias Druckman Andrew Funk Jean Carlos Acevedo PubMed Frederick R Carrick David J Traster Brian Sass Chriss Sass Elias Druckman Andrew Funk Jean Carlos Acevedo 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.

IMPROVEMENTS IN A PATIENT WITH MILD TRAUMATIC BRAIN INJURY AND DYSLEXIA FOLLOWING MULTIMODAL NEUROREHABILITATION

Event Abstract Back to Event IMPROVEMENTS IN A PATIENT WITH MILD TRAUMATIC BRAIN INJURY AND DYSLEXIA FOLLOWING MULTIMODAL NEUROREHABILITATION Frederick R. Carrick1* and David J. Traster1* 1 Carrick Institute, United States Background: We describe a 60 year-old male who presented to a chiropractic neurology clinic with a history of mild traumatic brain injury. The patient experienced severe dyslexia, migraines, photophobia, hyperacusis, lack of steadiness, autonomic changes and right sided hypertonicity of musculature. Methods: Upon comprehensive neurologic examination the patient demonstrated bilaterally non-responsive pupils upon direct light reflex, absence of adduction on left eye upon convergence testing, absent visual optokinetic nystagmus in all directions, and inability to read due to oculomotor deficits. The patient participated in a five day program of neurorehabilitation involving specific oculomotor therapy as well as off-vertical-axis-rotation therapy. Results: The patient experienced a normalization of visual optokinetic nystagmus responses. The patient improved reading comprehension as a result of improved version and vergence integrity. Conclusion: Integrated neurorehabilitation utilizing oculomotor, vestibular and physical rehabilitation produced significant improvements in a patient with dyslexia. The authors suggest further investigation into neurorehabilitation with dyslexia. Keywords: Traumatic brain injury (TBI), Dyslexia, Neurorehabilitation, concussion, concussion rehabilitation 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: Carrick FR and Traster DJ (2015). IMPROVEMENTS IN A PATIENT WITH MILD TRAUMATIC BRAIN INJURY AND DYSLEXIA FOLLOWING MULTIMODAL NEUROREHABILITATION. Front. Neurol. Conference Abstract: International Symposium on Clinical Neuroscience: TBI and Neurodegeneration. doi: 10.3389/conf.fneur.2015.58.00086 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: 03 Sep 2015; Published Online: 02 Nov 2015. * Correspondence: Prof. Frederick R Carrick, Carrick Institute, Cape Canaveral, United States, drfrcarrick@post.harvard.edu Dr. David J Traster, Carrick Institute, Cape Canaveral, United States, dtraster3@gmail.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 Frederick R Carrick David J Traster Google Frederick R Carrick David J Traster Google Scholar Frederick R Carrick David J Traster PubMed Frederick R Carrick David J Traster 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.

Up-down asymmetry in vertical induced motion and optokinetic nystagmus.

We investigated the effects of pursuit effort against the optokinetic nystagmus (OKN) on induced motion (IM) by measuring vertical IM and eye movements. Participants viewed an inducing stimulus (a random dot pattern) moving either upward or downward at the velocity of 10 or 40 °/s. A horizontally moving target (a single dot) was then presented within the inducing stimulus. Participants were asked to pursue the target and report the perceived slant of the target motion path by using a joystick. The results showed that IM magnitude was larger with an upward stimulation than with a downward stimulation. IM magnitude was also larger at 40 °/s than at 10 °/s. The results of eye movements prior to the target presentation showed that OKN was elicited more effectively with an upward stimulation than with a downward stimulation and at 40 °/s than at 10 °/s. OKN was markedly reduced when the target was presented within the inducing stimulus. These results support the oculomotor theory that IM magnitude reflects pursuit effort against OKN in response to an inducing stimulus.

Efficacy of a Computerized Optokinetic Nystagmus Test in Prediction of Visual Acuity of Better Than 20/200

To evaluate the efficacy of a computerized optokinetic nystagmus (OKN) test in detecting visual acuity (VA) of >20/200. This was a combined retrospective and prospective, noninterventional study. In phase I of the study, data from 168 eyes of 154 subjects who underwent the computerized objective VA test using OKN responses at Seoul National University Bundang Hospital were reviewed and reanalyzed, and a table for predicting the range of subjective VA for each step of objective VA was made. From the table, the cutoff value for detecting VA of >20/200 was determined. In phase II of the study, the distribution of subjective VA according to each objective VA step was determined for 80 eyes of 40 subjects at Seoul Veteran's Hospital. The sensitivity and the specificity of our cutoff value were evaluated in the two groups. No significant difference was found in the distribution of subjective VA according to objective VA steps between the two groups. For the subjects in phase I of the study, the sensitivity of our cutoff value was 91.7% and the specificity was 88.3%. For patients in phase II of the study, the sensitivity of our cutoff was 86% and the specificity was 96.7%. This study shows that an objective VA test using OKN responses can be effective in predicting real VA and detecting VA of >20/200.