Anatomy and Morphology DISTRIBUTION OF ION CHANNELS AND TRANSPORTER PROTEINS IN THE LATERAL WALL OF THE HUMAN COCHLEA-A SIMMICROSCOPY STUDY

Objective To investigate the clinical characteristics of otolith abnormal migration following canalith repositioning procedures(CRPs) for benign paroxysmal positional vertigo (BPPV) patients. The diagnosis, treatment and prevention approaches are also discussed. Methods Totally 356 cases of unilateral BPPV patients were treated by CRPs between January, 2010 and December, 2015. Otolith abnormal migration following CRPs were recorded and analyzed with type and risk factors. Results: The incidence rate of otolith abnormal migration in 356 cases was totally 4.78% (17/356), with canal conversion in 2.8% (10/356), cupulolithiasis and canalolithiasis conversion in 0.84% (3/356), and primarily canal reentry in 1.12% (4/356). The risk factors were Dix – Hallpike test immediately performed after CRPs (χ2= 27.512, P < 0.05) and another CRPs after treatment (χ2= 26.386P < 0.05). Sex, age, course, involved semicircular canals and whether CRPs in accordance with the standard was not significant (P > 0.05). Conclusion Otolith abnormal migration is a complication following CRPs for BPPV. Diagnosis is based on careful assessment of the symptom and the pattern of nystagmus observed after CRPs. To prevent the occurrence of otolith abnormal migration, another Dix – Hallpike test or CRPs immediately performed after treatment is not recommended. PP125 Benign Paroxysmal Position Vertigo DIAL “V” FOR VERTIGO: APPLICATION OF THE “A-VOR” APP IN BPPV TEACHING COURSES Julia DLUGAICZYK, Michael THIEMER, Christian NEUBERT, Bianca SCHORN, Bernhard SCHICK Department of Otorhinolaryngology, Saarland University Medical Center, Homburg/Saar, Germany, Germany Objective:BPPV is the most common disorder of the vestibular organ.However, this easy-to-cure cause of vertigo is still often misdiagnosed and left untreated in everyday clinical practice. Therefore, the present study aimed to inves212 Poster Presentations tigate whether the use of an app-based training tool (aVOR app: https://itunes.apple.com/de/app/avor/id497245573? mt= 8) in teaching courses for medical students improves their ability to perform the Epley repositioning maneuver for BPPV correctly. Methods: Students were randomly assigned to two variants of a BPPV teaching course (without aVOR app: n = 67; with aVOR app: n = 46). Students’ satisfaction was assessed with a standardized questionnaire for the evaluation of student courses at Saarland University Medical School. Furthermore, the students’ ability to perform the steps of the Epley maneuver in the correct order was tested at the end of the term. Results: Application of the aVOR app increased students’ satisfaction with the course in the following aspects: quality of teaching media, learning success, overall satisfaction, recommendation to other students (t-test: p 0.05, respectively). While 56% of students in the aVOR group were able to apply the steps of the Epley maneuver in the correct order, only 26% of the students in the group without the aVOR app succeeded in this task at the end of the term (Fisher’s exact test: p = 0.004). Conclusion: The aVOR app is a useful hands-on training tool for teaching the treatment of BPPV to medical students. PP126 Benign Paroxysmal Position Vertigo DIFFERENTIAL DIAGNOSIS OF GEOTROPIC POSITIONAL NYSTAGMUS IN PATIENTS WITH BPPV Suzuyo OKAZAKI, Takao IMAI, Kayoko HIGASHI-SHINGAI, Kazunori MATSUDA, Noriaki TAKEDA, Tadashi KITAHARA, Atsuhiko UNO, Arata HORII, Yumi OHTA, Tetsuo MORIHANA, Takashi SATO, Chisako MASUMURA, Suetaka NISHIIKE, Hidenori INOHARA Department of Otorhinolaryngology – Head And Neck Surgery, Osaka University Graduate School of Medicine, Japan Department of Otolaryngology, Suita Municipal Hospital, Japan Department of Otorhinolaryngology – Head And Neck Surgery, Tokushima University Graduate School of Medicine, Japan Department of Otolaryngology – Head And Neck Surgery, Nara Medical University, Japan Department of Otolaryngology – Head And Neck Surgery, Osaka General Medical Center, Japan Department of Otolaryngology Head And Neck Surgery, Niigata University Graduate School of Medical And Dental Sciences, Japan Department of Otorhinolaryngology – Head And Neck Surgery, Osaka Rosai Hospital, Japan Patients with the horizontal canal type of benign paroxysmal vertigo (H-BPPV) show geotropic (GH-BPPV) or apogeotropic positional nystagmus. There are two types of geotropic positional nystagmus, one is transient (TGPN) and the other is persistent (PGPN). In ENT office, differentiation between TGPN and PGPN is determined in patients with GH-BPPV, based on whether their nystagmus gradually declined or not by means of an infrared CCD camera or Frenzel glasses. In the present study, we analyzed positional nystagmus three-dimensionally in 47 patients with GH-BPPV and diagnosed TGPN and PGPN with time constant (TC) of slow phase of eye velocity of positional nystagmus. TGPN with TC of> 35 sec was diagnosed in 36 patients and PGPN with TC of< 35 sec was diagnosed in 11 patients. Ten independent otolaryngologists then distinguished TGPN from PGPN after 10 secor 30 secobservation of positional nystagmus image recording of an infrared CCD camera. The sensitivity and specificity for discrimination of TGPN after 30 sec-observation of positional nystagmus was 100% and 97%, respectively. These findings suggested that 30 sec-observation of positional nystagmus image recording with an infrared CCD camera is sufficient to distinguish TGPN from PGPN of patients with H-BPPV in ENT office. PP127 Benign Paroxysmal Position Vertigo A CASE WITH VARIOUS NYSTAGMUS INVERSIONS IN THE HORIZONTAL CANAL VARIANT OF BENIGN PAROXYSMAL VERTIGO. Yasuo OGAWA, Koji OTSUKA, Taro INAGAKI, Noriko NAGAI, Mamoru SUZUKI, Kiyoaki TSUKAHARA Poster Presentations 213 Department of Otorhinolarungology, Tokyo Medical University Hachioji Medical Center, Japan Department of Otorhinolarungology, Tokyo Medical University, Japan Introduction: The horizontal canal variant of benign paroxysmal vertigo (HC-BPPV) is characterized by a bidirectional-changing positional nystagmus with a positional change. Canalolithiasis and Cupulolithiasis may both play a role in HC-BPPV. Some patients with HC BPPV present with spontaneous inversion of nystagmus without a positional change. We encountered a case with various nystagmus inversions of positional test during follow up and we speculate on the possible mechanism of nystagmus inversion. The case was 63-year-female. The patient had the positional changing geotropic nystagmus on the both sides, showing spontaneous inversion of direction in both sides. The patient was diagnosed as having HC-BPPV. At the second visit, the patient showed the positional changing ageotropic nystagmus. We tried the head-shaking as a treatment, after that the patient showed geotropic nystagmus. At the third visit, the nystagmus was disappeared. Conclusion: The coexistence of cupulolithiasis and canolithiasis appeared to be a possible mechanism of nystagmus inversion. PP128 Benign Paroxysmal Position Vertigo NATURAL HISTORY OF HORIZONTAL CANAL BENIGN PAROXYSMAL POSITIONAL VERTIGO IS TRULY SHORT Dae Bo SHIM, Mee Hyun SONG, Hong Ju PARK Department of Otorhinolaryngology, Myongji Hospital, Seonam University College of Medicine, Korea Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Korea The objective of the study is to characterize the natural course of positional vertigo and nystagmus in patients with horizontal canal benign paroxysmal positional vertigo (h-BPPV) and to analyze the difference in the natural course between the two variants of h-BPPV. We conducted a prospective study in 106 patients with geotropic type h-BPPV [h-BPPV (Geo)] (n = 43) and apogeotropic type h-BPPV [h-BPPV (Apo)] (n = 63) who agreed and signed the written informed consent of no treatment. All patients were asked to answer a detailed interview about the onset time of positional vertigo and to visit the hospital every 1–3 days. At every visit, they were interviewed about cessation time of positional vertigo and positional nystagmus was assessed. The mean period ± SD between the onset and remission of vertigo in the h-BPPV (Geo) was 6.7 ± 6.3 days, whereas that in the h-BPPV (Apo) was 3.7 ± 4.1 days. In addition, the mean period ± SD from the initial diagnosis to the disappearance of positional nystagmus in the h-BPPV (Geo) was 4.7± 3.9 days, whereas that in the h-BPPV (Apo) was 4.4± 5.0 days. Although the duration until natural remission of positional nystagmus did not differ between the two variants of h-BPPV, the remission of vertigo occurred faster in h-BPPV (Apo) than h-BPPV (Geo) (p < 0.05). The positional vertigo disappeared faster in the h-BPPV (Apo) compared to the h-BPPV (Geo) unlike the positional nystagmus. PP129 Benign Paroxysmal Position Vertigo THERAPEUTIC EFFICACY OF A MODIFIED EPLEY’S MANEUVER UNDER THE ‘SHOULDER ON THE PILLOW’ POSITION Jae-Hyun SEO, Dong-Hee LEE, Eun-Ju JEON, Jeong-Hoon OH, Ho-Seok LEE, Ki-Hong CHANG, YongSoo PARK, Sang-Won YEO Department of Otorhinolaryngology, College of Medicine, the Catholic University of Korea, Korea Purpose: The authors designed a modified Dix-Hallpike test and subsequent modified Epley’s maneuver under ‘shoulder on the pillow’ position, which places a pillow under the patient’s shoulders so that when the neck extends, the head touches the bed floor. The aim of this study is to evaluate the usefulness of our modification of canalith repositioning maneuver(CRM) for posterior canal benign paroxysmal positional vertigo. Method: This study was multi-institutional, prospective, randomized, single-blind, and controlled clinical study. Using a random table, the patient was assigned to groupA and group B. Group A patients were performed a modified 214 Poster Presentations Epley’s maneuver under the classical head-hanging position, and group B patents were performed a modified Epley’s maneuver under the ‘shoulder on the pillow’ position. The presence of nystagmus and vertigo on positional testing were evaluated at a week after one session of CRM. Result: Three university hospitals participated in this study, and the total number of patients included in this study was 41 patients. Out of 41 patients, 21 patients assigned to group A and 20 patients assigned to group B. Resolution rates at 1 week after treatment were 85.7% in group A and 85% in group B. Conclusion: The therapeutic efficacy of a modified Epley’s maneuver under the ‘shoulder on the pillow’ position was equivalent to a modified Epley’s maneuver under classical head-hanging position. Thus, this modification may be an alternative when the patient cannot take a head-hanging position. PP130 Benign Paroxysmal Position Vertigo THE VIDEO HEAD IMPULSE TEST IN POSTERIOR CANAL BENIGN PAROXYSMAL POSITIONAL VERTIGO(P-BPPV) Jeesun CHOI, Seung-Chul LEE, Joong-Wook SIN, Hong-Joon PARK, Ho-Ki LEE Department of Otolaryngology, Soree Ear Clinic, Korea Objectives: To investigate the clinical characteristics and the results of video head impulse test (vHIT) of p-BPPV. Materials andMethods:We retrospectively analyzed 169 patients with idiopathic p-BPPV. All patients were tested with video-nystagmography that included the Dix-Hallpike test. In addition, we evaluated the results of vHIT in the posterior canal plane before and after canalith repositioning maneuver (CRM). We divided p-BPPV patients into two groups, which could be achieved successful treatment in initial (s-CRM) or not (n-CRM). Finally, we further analyzed patients with positive vHIT. Results:Of the 169 p-BPPV patients, 11 (6.5%) showed positive ipsilesional vHIT in posterior canal plane. Average age of positive vHIT group was significantly older than negative vHIT group. (p = 0.00) While 82.9% of patients with negative vHIT were successfully treated in the initial visit day, 63.6% of patients with positive vHIT could be achieved successful repositioning, but there was no statistical significance. (p = 0.11) Duration of positioning nystagmus in s-CRM group was significantly longer than n-CRM group. (p = 0.013) Of 11 patients of positive vHIT, 4 patients showed negative conversion. But 4 patients showed positive vHIT even at follow up period regardless of successful repositioning. Conclusions: In about 6.5% of p-BPPV patients, the deficit of VOR for ipsilesional posterior canal could be concurrent. But, positive vHIT did not showed firm correlation with treatment outcome. In addition, positive vHIT results in some patients could be normalized after reposition within right after reposition or few days. Therefore, different mechanism in generation of positive vHIT might exist, such as otolith movement. PP131 Benign Paroxysmal Position Vertigo DISCREPANCY BETWEEN THE RESULTS OF CANAL FUNCTION TESTS IN PATIENTS WITH BENIGN PAROXYSMAL POSITIONING VERTIGO Jeong-Hoon OH, Young-Hoon CHOUNG, Ki-Hong CHANG, Byung-Guk KIM Department of Otorhinolaryngology-Head and Neck Surgery, The Catholic University of Korea, Seoul, Korea Background and purpose: Caloric irrigation is a non-physiological and time-consuming examination which tests horizontal vestibular ocular reflex (hVOR) in the low-frequency range of up to 0.003 Hz. In contrast, video-head impulse test (vHIT) is easy to perform and examines the hVOR in its physiological working range of 4–7 Hz. Compared with the caloric test, vHIT have shown high specificity (90–100%) but low sensitivity (34–56%) in different peripheral vestibular diseases. Canal paresis in patients with benign paroxysmal positioning vertigo (BPPV) has been variously reported to be present in 26 to 50%. The aim of this study was to compare the results of caloric testing and vHIT in patients with BPPV. Method: Patients with BPPV (n=26) were tested by vHIT and caloric testing. We compared VOR gain and catch-up saccades of vHIT with the canal paresis of caloric testing. Poster Presentations 215 Results: The caloric test was abnormal in 38% of patients with BPPV, while the vHIT showed an abnormal VOR gain in only 10.4% of BPPV patients (p < 0.05). However, vHIT revealed catch-up saccades in 25% of BPPV patients, and therefore, 43% of BPPV patients showed VOR deficits. In all, 60% of patients with an abnormal caloric test had a normal vHIT, whereas 71% of those with an abnormal vHIT had a normal caloric test. Conclusion: This study shows a significant discrepancy between the results of caloric testing and vHIT in the patients with BPPV. To improve the diagnostic value of vHIT in BPPV, further evaluation about the significance of gain asymmetry and objective criteria for the detection of catch-up saccades are also needed. PP132 Benign Paroxysmal Position Vertigo IDENTIFICATION OF BENIGN PAROXYSMAL POSITIONAL VERTIGO MUST BE INCLUDED IN FALLS SERVICES Joanna LAWSON, Steve PARRY, Nicholas LAWSON Department of Falls And Syncope, Royal Victoria Infirmary, Newcastle Upon Tyne, United Kingdom Department of Ageing Research, Newcastle University, United Kingdom Department of General Practice, Monkseaton Medical Centre, Whitley Bay, Tyne And Wear, United Kingdom Introduction: BPPV is a significant risk factor for falls but under diagnosed. This falls prevention service aimed to identify and modify risk factors for falls in a large community dwelling population (145,000 total primary care list size) using an integrated care model. Methods: Audit of GP computerized records followed by postal questionnaire identified all persons over 60 with recognized risk factors for falls. This group underwent a comprehensive community based assessment including: Physiotherapy assessment. Nurse review: ECG, Lying and standing BP, MMSE, GDS, FES, visual acuity Medical assessmenttargeted history and examination for dizziness, vertigo, falls and syncope, FRAX score/bone health. Recommendations given to GP on new diagnoses made. Results: 4038 patients assessed in 4 years. 174 new diagnoses of posterior canal BPPV 4.3% prevalence. Mean age 73.8. Range 60–91 62% females. 52% had fallen 54% had right, 38% left and 8 % bilateral BPPV. 1 Horizontal. Duration of symptoms 2 months to 10 years. Additional intervention was 27% of these patients referred to balance class, 17% referred for DEXA on basis of FRAX tool, 7% had orthostatic hypotension, 5% bradycardia requiring review, also new atrial fibrillation, depression, cognitive impairment identified. Conclusion: Active identification and treatment of BPPV must be part of falls prevention services. Any service seeing older persons with BPPV should consider additional modifiable risk factors for falls including gait disorders, osteoporosis, cardiovascular diagnoses with the aim of reducing falls. PP133 Benign Paroxysmal Position Vertigo NYLEN-BARANY POSITIONING TEST Judith Ann WHITE Department of Otolaryngology, Swedish Neurosciences Institue, USA The Nylen-Barany positioning testing is a useful addition to standard Dix-Hallpike positioning testing. The history and technique of the Nylen-Barany positioning test is reviewed, and the clinical utility of the test in diagnostic vestibular assessment is illustrated with case studies of patients who repeatedly do not show nystagmus with DixHallpike positioning but demonstrate vigorous torsional nystagmus consistent with posterior semicircular canal BPPV when Nylen-Barany positioning is performed. Horizontal nystagmus may also be elicited by the NylenBarany positioning test, suggesting lateral semicircular canal BPPV. 216 Poster Presentations PP134 Bilateral Vestibulopathy A CASE OF NONENCEPHALOPATHIC VESTISBULAR WERNICKE SYNDROME Jong-Min LEE, Jae-Chan RYU, Sun-Young KIM, Jee-Hyun KWON, Ji-Yun PARK Department of Neurology, Ulsan University Hospital, Ulsan University Collage of Medicine, Ulsan, Korea Wernicke’s encephalopathy is an acute, neuropsychiatric syndrome that results from a deficiency vitamin B1 (thiamine). Its essential features are ophthalmoplegia and/or nystagmus, mental status changes, and unsteadiness of stance and gait. Non-encephalopathic presentations of CNS thiamine deficiency may be difficult to diagnosis. We describe vestibular signs during the early phase of suspected Wernicke encephalopathy without encephalic symptoms. A 64-year-oldmale presented oscillosia and disequilibrium for 3 days. He had a history of chronic alcoholics without vascular risk factors. Neurologic examination showed horizontal gaze-evoked nystagmus(GEN), spontaneous UBN, bilateral HIT signs and trunkal ataxia without limbs ataxia. He had normal orientation and sensorium, had a normal Mini-Mental State Examination score (30/30). He showed no response to bithermal caloric irrigation of each ear and bilaterally abnormal horizontal head impulse tests. Rotatory chair test showed low gain, phase lead and no asymmetry, Brain MRI shows diffuse cerebellar and cerebral atrophy without acute focal CNS structural lesion. We began thiamine replacement following clinical examination. He improved dramatically after IV thiamine. Thiamine deficiency should be considered acute bilateral combined vestibulopathy(bilateral vestibular failure plus GEN with/without vertical nystagmus) even absent encephalic symptom. Supplement of high dose IV thiamine is essential for both therapeutic and diagnostic approach. PP135 Bilateral Vestibulopathy BILATERAL VESTIBULAR HYPOFUNCTION: INSIGHTS IN ETIOLOGIES, CLINICAL SUBTYPES AND DIAGNOSTICS R. VAN DE BERG, F. LUCIEER, P. VONK, N. GUINAND, R. STOKROOS, H. KINGMA Department of OtorhinolaryngologyAnd Head And Neck Surgery, Division of Balance Disorders, Faculty of Health Medicine And Life Sciences, School For Mental Health And Neuroscience, Maastricht University Medical Center, Maastricht, Netherlands Department of Health, Medicine And Life Sciences, Maastricht University, Maastricht, Netherlands Department of Clinical Neurosciences, Service of Otorhinolaryngology And Head And Neck Surgery, Geneva University Hospitals, Geneva, Switzerland Department of Physics, Tomsk State Research University, Russia Introduction:Bilateral vestibular hypofunction (BVH) is a heterogeneous condition for which no definite diagnostic criteria have been established yet. In order to develop specific criteria, more insight is needed in etiologies, clinical subtypes and the value of diagnostic tools. Objective: To evaluate the different etiologies and clinical subtypes of BVH and the value of diagnostic tools in the diagnostic process of BVH. Materials and methods: A retrospective case review was performed on 154 patients diagnosedwith BVH, between 2013 and 2015. Inclusion criteria: 1) imbalance and/or oscillopsia during locomotion, and 2) summated slow phase velocity of nystagmus of less than 20 degrees per second during bithermal caloric tests. Results: BVH resulted from more than 20 different etiologies. In the idiopathic group, the percentage of migraine was significantly higher compared to the non-idiopathic group (50% versus 11%, p < 0.001). All 4 clinical subtypes were found. Slowly progressive BVH with ataxia comprised only 4.5% of the cases. The head impulse test was abnormal in 94%, the torsion swing test was abnormal in 66%, bilateral normal hearing to moderate hearing loss was found in 49% and cerebral imaging was abnormal in 14% of the population. Conclusion: BVH has various etiologies and clinical characteristics. Migraine seems to play a significant role in idiopathic BVH. The torsion swing test is not the “gold standard” for diagnosing BVH due to its lack of sensitivity. Future diagnostic criteria of BVH should consist of standardized vestibular tests combined with a history that is congruent with the vestibular findings. Poster Presentations 217 PP136 Central Vestibular Disorders NON PHOSPHORYLATED NEUROFILAMENT LABELLING IN HUMAN DEITERS’ VESTIBULAR NUCLEUS NEURONS IN PARKINSON’S DISEASE Thomas P WELLINGS, Alan M BRICHTA, Rebecca LIM Department of Biomedical Sciences And Pharmacy, The University of Newcastle, Australia Department of Brain And Mental Health, Hunter Medical Research Institute, Australia Department of Neurology, John Hunter Hospital, Australia Background:A characteristic feature of lateral vestibular nucleus (LVN) is the presence of large multipolar neurons called Deiters’ neurons. Their descending axons project ipsilaterally in the spinal cord as the lateral vestibulospinal tract. Deiters’ neurons also express the cytostructural protein, non-phosphorylated neurofilament protein (NPNFP). NPNFP is expressed in other populations, including motoneurons and dopaminergic neurons of the substantia nigra. Studies show decreased striatal NPNFP-immunoreactivity in patients with Parkinson’s disease (PD), but not in progressive supranuclear palsy (PSP). Although both these disorders exhibit impaired postural reflexes, we hypothesised that NPNFP-expression is altered in Deiters’ neurons in patients with PD and postural instability. Methods: All procedures were approved by The University of Newcastle Human Ethics Committee. Tissue from 6 controls, 6 PD donorswith postural instability, and 2 PSP donors, was provided by the Sydney Brain Bank, Australia. For each donor, 5 brainstem sections (50 μm) containing the LVN were labelled. NPNFP-immunopositive neurons with an area of > 2000 μm2 (diameter > 50μm) and within the boundaries of the LVN were counted as Deiters’ neurons. Results: In controls, there were 25.6 ± 3.0 NPNFP immunopositive Deiters’ neurons/section. In PD donors there was a 50% decrease in the number of NPNFP immunopositive neurons with only 13.0 ± 2.0 neurons/section (p < 0.01). In contrast, there were no differences in neuronal counts between PSP (n = 22.8 ± 3.0 neurons/section) and controls. Conclusion: The decline in expression of NPNFP in patients with PD corresponds to a deterioration in descending reflexive postural control. This finding supports the notion for a pathophysiological explanation of postural instability in Parkinson’s disease. PP137 Central Vestibular Disorders EVALUATION OF EYE MOVEMENTS AND VESTIBULAR FUNCTION IN POSTERIOR CIRCULATION STROKE PATIENTS Sang WENWEN, Wang WEIYING, Xu ZHIWEI, Hong YUAN, Yan SHUANGMEI, Yang XU Department of Neurology, The Graduate Student Training Base-aerospace Center Hospital of Liaoning Medical University, China Department of Neurology, The Graduate Student Training Base-aerospace Center Hospital of Liaoning Medical University, China Department of Neurology, The Graduate Student Training Base-aerospace Center Hospital of Liaoning Medical University, China Department of Neurology, The Graduate Student Training Base-aerospace Center Hospital of Liaoning Medical University, China Department of Neurology, Peking University Health Science Center, China Department of Neurology, Aerospace Center Hospita, China Objective: The aim of this study was to determine the importance of eye movements and vestibular function in diagnosing Posterior circulation stroke. Methods: A total of 37 posterior circulation stroke patients with confirmed PCS diagnosis and neuroimaging results were included in this study. Clinical information of the involved patients was collected including gender, age, onset symptom, risk factors and admission signs. All patients underwent a series of tests using videonystagmography for noninvasive evaluation of the eye movements and vestibular function. Results: 29 (78.4%) patients showed at least one abnormality in eye movement including 4 by gazes test, 11 by saccade test, 15 by smooth pursuit test and 12 by optokinetic nystagmu test. In terms of the vestibular function, 218 Poster Presentations spontaneous nystagmus was observed in 13 (35.1%) patients. head shaking nystagmus was observed in 14 (45.1%) patients. Impaired fixation suppression was observed in 9 (27.2%) patients. Relating the assessment of eye movements and vestibular function to the neuron imaging revealed that Cerebellar infarction in the territory of Posterior Inferior Cerebellar Artery was most frequent in patients with isolated vertigo. In addition, the horizontal component of the spontaneous nystagmus and the head shaking nystagmus always beat toward the lesion side. Fixation suppression test was usually successful. Downbeat nystagmus can be induced in patients with of pontine infarcts. In those patients, fixation suppression test was usually failed. Conclusion: Abnormities in eye movements is common in PCS patients presented with dizziness/vertigo and can be used to screen the patients. PP138 Central Vestibular Disorders MODULATION OF CENTRAL NYSTAGMUS BY VISION, PROPRIOCEPTION, AND EFFERENCE COPY SIGNALS: A SYSTEMATIC EVALUATION Jeong-Yoon CHOI, Ji-Soo KIM Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea, Korea Non-vestibular sensorimotor signals modulate the vestibular nucleus neuron to achieve current behavioral goals, and may generate or modulate nystagmus. In central lesions affecting the vestibular nuclei, non-vestibular signals such as mastication or swallowing may induce nystagmus. However, the influence of non-vestibular signals on these types of nystagmus has not been investigated in a systematic way and the underlying mechanisms of the modulation are poorly understood. In this study, several non-vestibular sensorimotor stimuli were applied to evaluate the patterns of nystagmus modulation in a patient with suspected rhombencephalitis or imaging negative small infarction, probably involving the left dorsolateral medulla. The nystagmus was induced or significantly modulated by i) visual inputs, and ii) combined proprioceptive and efference copy signals (during voluntarymotion) unrelated to body or head orientation. In contrast, isolated proprioceptive signal, mental set, or non-proprioceptivesomatosensory inputs showed a negligible effect on the induction of nystagmus. Based on these modulations, we suggest that i) the visually-mediated nystagmus is due to a lesion-induced pursuit asymmetry, and ii) the nystagmus induced during voluntary motion is due to erroneous contribution of combined proprioceptive and efference copy signals during integration of non-vestibular signals for ocular motor control. Various non-vestibular sensorimotor stimulations may induce nystagmus due to dysfunction of the central vestibular neural circuity. PP139 Central Vestibular Disorders DOWNBEAT NYSTAGMUS ASSOCIATED WITH BILATERAL PARAMEDIAN TRACT NEURONS LESION IN PONS Ji-Yong LEE Department of Neurology, Yonsei University Wonju College of Medicine, Korea Introduction: Downbeat nystagmus is characterized by slow upward drifts and fast downward phases. Downbeat nystagmus may be caused by lesions of the vestibulocerebellum, toxic adverse effects of medication (for example, phenytoin, carbamazepine, lithium, morphine derivatives) and brainstem stroke. So far, there have been only a few reports about paramedian poninte tegmentum lesion associated with downbeat nystagmus. I report a case with downbeat nystagmus associated with bilateral paramedian tract neurons lesion in pons. Case:A 73-year-old-womanpresented with dizziness for 5 days. Four years previously, she had suffered a infarction in pontine tegmentum with bilateral internuclear ophthalmoplegia. On admission, she had downbeat nystagmus using Frenzel goggles with full range of motion of both eyes. Downbeat nystagmus was observed in the primary eye position and was increased in lateral gaze, especially to the right. Her brain magnetic resonance imaging revealed an old infarction in pontine tegmentum including bilateral medial longitudinal fasciculus with small vessel disease. Conclusion: This case report suggests that paramedian tract neurons may play an important role in the vertical vestibular balance control. Poster Presentations 219 PP140 Central Vestibular Disorders ABNORMAL EYE MOVEMENTS IN NUCLEUS PREPOSITUS HYPOGLOSSI LESIONS Sung-Hee KIM, Hyo Jung KIM, David ZEE, Ji-Soo KIM Department of Neurology, Seoul National University Bundang Hospital, Korea Department of Biomedical Laboratory Science, Kyungdong University, Korea Department of Neurology, Ophthalmology, Otolaryngology – Head And Neck Surgery, The Johns Hopkins University School of Medicine, USA Department of Neurology, Kyungpook National Univesity Hospital, Korea The nucleus prepositus hypoglossi (NPH) is a key constituent of a vestibular-cerebellar-brainstem neural network that ensures the eyes hold steady in desired positions of gaze. Nine patients with a lesion involving the NPH showed ipsilesionally beating spontaneous nystagmus, horizontal gaze-evoked nystagmus more intense on looking toward the lesion side, impaired smooth pursuit more to the lesion side, central patterns of head shaking nystagmus, static ocular contrapulsion, and decreased gain of the vestibulo-ocular reflex during contralesionally-directed head impulses. These ocular motor findings may be ascribed to an imbalance in the NPH-inferior olive-flocculus-vestibular nucleus loops on both sides of the brainstem. A unilateral NPH lesion may present acute vestibular syndrome with a unique pattern of ocular motor abnormalities. PP141 Central Vestibular Disorders VOR DYNAMICS DURING PASSIVE HEAD-IMPULSES: SLOW PHASE AND QUICK-EYE MOVEMENTS IN HUNTINGTON’S DISEASE Leonel LUIS, João COSTA, Esteban MUNOZ, Erich SCHNEIDER, Josep VALLS-SOLÉ Department of Clinical Physiology Translational Unit, Imm, Faculty of Medicine, University of Lisbon, Portugal Department of Otolaryngology, Hospital De Cascais, Portugal Department of Neurology, Emg And Motor Control Unit, Hospital Clínic, Universitat De Barcelona, Spain Department of Institute of Medical Technology, Brandenburg University of Technology, Germany Angular vestibular ocular reflex (VOR) can be assessed with the video head-impulse test (vHIT), allowing the quantification of VOR) at a physiological frequency domain, as well as the characterization of quick eye movements (QEM) triggered with head impulses. We explored 18 genetically confirmed HD patients (44.7 ± 8.1 years; male = 9), classified as Shoulson and Fahn severity stages 1 (n = 5; pre-symptomatic), 2 (n = 4), 3 (n = 8) and 4 (n = 1) based on their Total Functional Capacity (TFC) scores, and 40 healthy controls (39.9 ± 16.5 years; male = 20). We calculated the VOR latency and gain and determined the latency, peak-velocity and occurrence rate of the QEM triggered during and after head impulses. VOR latency and gain were not different from controls (p > 0.29 for both comparisons). No differences were found between presymptomatic and symptomatic patients. QEM were present in 11 patients and 18 controls, always after the head impulse and compensatory. QEM latency (174.5 ± 41.2 ms), peak velocity (71.58 ± 34.48◦/s) and occurrence rate (0.45 ± 0.29) were not different from controls (p > 0.11 for all comparisons). Though not realizing it, 5 of the symptomatic patients majorly failed to direct gaze in darkness, both horizontal as vertically, this correlating with TFC scores (Spearman r = 0.65, p = 0.005). VOR seems to be preserved at physiological frequency domains in HD patients, even in more advanced stages of the disease. Although both voluntary saccades and quick phases of nystagmus are known to be slower in HD, quick eye movements triggered with impulses showed no differences in comparison to controls. Gaze failure in darkness may prove beneficial as a biological marker for HD. 220 Poster Presentations PP142 Central Vestibular Disorders THE INCIDENCE OF ABNORMAL SUBJECTIVE VISUAL VERTICAL IN MULTIPLE SCLEROSIS DURING ROD AND ROD-AND-FRAME CONDITIONS Brooke N KLATT, Patrick J SPARTO, Lauren TERHORST, Stanley WINSER, Rock HEYMAN, Islam ZAYDAN, Susan L WHITNEY Department of Physical Therapy, University of Pittsburgh, USA Department of Occupational Therapy, University of Pittsburgh, USA Department of Physiotherapy, University of Otago, New Zealand Department of Neurology, University of Pittsburgh, USA Purpose: Disruption of the vestibular system resulting from the pathophysiology of multiple sclerosis (MS) is not uncommon. Subjective Visual Vertical (SVV) deviations (rod condition) are correlated to abnormal cerebellar function in individuals diagnosed with MS but SVV during static visual disturbances (rod-and-frame condition) have not been investigated. Additionally, the relationship between SVV abnormalities and functional outcome measurements have not been explored within this population. Method: Twenty participants (15 females), mean age 54.5 years old (± 7.03 SD), who were diagnosed with MS by a neurologist and had signs of cerebellar involvement (gait ataxia, limb ataxia, dysarthria, and/or nystagmus) completed the Barthel Index questionnaire, Berg Balance Scale (BBS), gait velocity, and computerized SVV testing. SVV testing included 4 trials of the rod only condition, 4 trials of the rod-and-frame condition with the frame rotated clockwise (CW), and 4 rod-and-frame condition trials with the frame rotated counter clockwise (CCW). Outcomes: Only four participants yielded results within normal limits for all three SVV testing conditions. Each of these four participants scored 100 on the Barthel Index (40% of the sample scored 100/100), BBS scores 52/56 (45% of the sample scored 52/56), and gait velocities 1.0 m/sec (45% of the sample had gait velocities 1.0 m/sec). Conclusion: In this sample, 80% of the individuals displayed SVV abnormalities. Implementation of SVV assessment for individuals with MS may provide valuable information to identify the best interventions and with future research, may potentially have predictive power in determining functional impairment and fall risk. PP143 Central Vestibular Disorders A RADIOGRAPHIC TARGET SIGN FOR ABNORMAL VERTEBRAL ARTERY FLOW IN STROKE PATIENTS WITH ACUTE VESTIBULAR SYNDROME Jorge C KATTAH, Ali S SABER THERANI, Jeffrey DE SANTO, John H PULA, David E NEWMAN TOKER Department of Neurology, University of Illinois College of Medicine. Peoria. Illinois Neurologic Institute, USA Department of Neurology, Johns Hopkins University, USA Objective: To identify vertebral artery (VA) flow abnormality seen as V4 segment hyper-intensity on axial T2MRI in patients with acute vestibular syndrome (AVS), and investigate association with stroke. Methods:Retrospective study of 223AVS patients; 140 had available T2MRI scan (153 scans). MRIs were reviewed blindly by a neuro-radiologist and a clinician for presence of V4 segment hyper-intensity or asymmetry (target sign). We report target sign presence, odds ratio, target sign and lesion laterality, target sign in negative initial DWI MRI, and Kappa for inter-rater reliability. Results: Of the 140 AVS patients, 68 had stroke, 72 vestibular neuritis (VN). VAV4 segment hyper-intensity was seen in 45.6% of strokes (37/68), and 5.6% of patients with VN (4/72). Odds of stroke in patients with a “target sign” was 20.3 (95%CI 6.6–61.9). Except in one stroke patient, all found target signs were ipsilateral to stroke side. Among stroke patients with negative initial DWI MRI, 50% (6/12) had a VAV4 segment hyper-intensity. Cohen’s kappa was 0.78. Conclusion: The VAV4 segment hyper-intensity or “target sign” identified pathologic VA abnormalities in a nearly half of stroke patients presenting with AVS. When the vertebral artery is involved in the pathogenesis of the stroke, search for a target sign may detect an abnormality that precedes changes in DWI MRI Poster Presentations 221