Journal of Vestibular Research - Volume 27, issue 4

Authors: Strupp, Michael | Kim, Ji-Soo | Murofushi, Toshihisa | Straumann, Dominik | Jen, Joanna C. | Rosengren, Sally M. | Della Santina, Charles C. | Kingma, Herman

Article Type: Research Article

Abstract: This paper describes the diagnostic criteria for bilateral vestibulopathy (BVP) by the Classification Committee of the Bárány Society. The diagnosis of BVP is based on the patient history, bedside examination and laboratory evaluation. Bilateral vestibulopathy is a chronic vestibular syndrome which is characterized by unsteadiness when walking or standing, which worsen in darkness and/or on uneven ground, or during head motion. Additionally, patients may describe head or body movement-induced blurred vision or oscillopsia. There are typically no symptoms while sitting or lying down under static conditions. The diagnosis of BVP requires bilaterally significantly impaired or absent function of the …vestibulo-ocular reflex (VOR). This can be diagnosed for the high frequency range of the angular VOR by the head impulse test (HIT), the video-HIT (vHIT) and the scleral coil technique and for the low frequency range by caloric testing. The moderate range can be examined by the sinusoidal or step profile rotational chair test. For the diagnosis of BVP, the horizontal angular VOR gain on both sides should be <0.6 (angular velocity 150–300°/s) and/or the sum of the maximal peak velocities of the slow phase caloric-induced nystagmus for stimulation with warm and cold water on each side <6°/s and/or the horizontal angular VOR gain <0.1 upon sinusoidal stimulation on a rotatory chair (0.1 Hz, Vmax = 50°/sec) and/or a phase lead >68 degrees (time constant of <5 seconds). For the diagnosis of probable BVP the above mentioned symptoms and a bilaterally pathological bedside HIT are required. Complementary tests that may be used but are currently not included in the definition are: a) dynamic visual acuity (a decrease of ≥0.2 logMAR is considered pathological); b) Romberg (indicating a sensory deficit of the vestibular or somatosensory system and therefore not specific); and c) abnormal cervical and ocular vestibular-evoked myogenic potentials for otolith function. At present the scientific basis for further subdivisions into subtypes of BVP is not sufficient to put forward reliable or clinically meaningful definitions. Depending on the affected anatomical structure and frequency range, different subtypes may be better identified in the future: impaired canal function in the low- or high-frequency VOR range only and/or impaired otolith function only; the latter is evidently very rare. Bilateral vestibulopathy is a clinical syndrome and, if known, the etiology (e.g., due to ototoxicity, bilateral Menière’s disease, bilateral vestibular schwannoma) should be added to the diagnosis. Synonyms include bilateral vestibular failure, deficiency, areflexia, hypofunction and loss. Show more

Keywords: Bilateral vestibulopathy, vertigo, dizziness, disequilibrium, vestibular, diagnostic criteria, Bárány Society

DOI: 10.3233/VES-170619

Citation: Journal of Vestibular Research, vol. 27, no. 4, pp. 177-189, 2017

Authors: Staab, Jeffrey P. | Eckhardt-Henn, Annegret | Horii, Arata | Jacob, Rolf | Strupp, Michael | Brandt, Thomas | Bronstein, Adolfo

Article Type: Research Article

Abstract: This paper presents diagnostic criteria for persistent postural-perceptual dizziness (PPPD) to be included in the International Classification of Vestibular Disorders (ICVD). The term PPPD is new, but the disorder is not. Its diagnostic criteria were derived by expert consensus from an exhaustive review of 30 years of research on phobic postural vertigo, space-motion discomfort, visual vertigo, and chronic subjective dizziness. PPPD manifests with one or more symptoms of dizziness, unsteadiness, or non-spinning vertigo that are present on most days for three months or more and are exacerbated by upright posture, active or passive movement, and exposure to moving or complex …visual stimuli. PPPD may be precipitated by conditions that disrupt balance or cause vertigo, unsteadiness, or dizziness, including peripheral or central vestibular disorders, other medical illnesses, or psychological distress. PPPD may be present alone or co-exist with other conditions. Possible subtypes await future identification and validation. The pathophysiologic processes underlying PPPD are not fully known. Emerging research suggests that it may arise from functional changes in postural control mechanisms, multi-sensory information processing, or cortical integration of spatial orientation and threat assessment. Thus, PPPD is classified as a chronic functional vestibular disorder. It is not a structural or psychiatric condition. Show more

Keywords: Chronic subjective dizziness, phobic postural vertigo, space motion discomfort, visual vertigo, classification, Bárány Society

DOI: 10.3233/VES-170622

Citation: Journal of Vestibular Research, vol. 27, no. 4, pp. 191-208, 2017

Authors: Horii, Arata | Mitani, Kenji | Masumura, Chisako | Uno, Atsuhiko | Imai, Takao | Morita, Yuka | Takahashi, Kuniyuki | Kitahara, Tadashi | Inohara, Hidenori

Article Type: Research Article

Abstract: BACKGROUND: Due to spatial disorientation reported in space, spatial memory and navigation performances could be more largely impaired by gravity changes. Hippocampus, a key structure for spatial memory, receives inputs from gravity-sensing otolith organs. OBJECTIVE: To determine the key molecules in the rat hippocampus that contribute to an adaptation to altered gravity in terms of spatial memory performance. METHODS: Gene expression of hippocampus and spatial memory after continuous two-weeks exposure to 2 G hypergravity (HG) were examined using a microarray analysis followed by real-time PCR methods and radial arm maze testing, respectively. Serum cortisol levels during HG …load were measured as a stress marker. RESULTS: Accuracy to enter the correct arms in HG rats was significantly lower than that of controls, indicating an impaired spatial memory due to gravity changes. Microarray analysis followed by real-time PCR confirmed an upregulation of insulin like growth factor binding protein 2 (IGFBP2) gene. Serum cortisol level was the same level as controls at the last day of hypergravity, suggesting the adaptation to HG-induced stress. CONCLUSIONS: Given that the IGF systems are involved in neurotrophic and synaptic plasticity mechanisms, IGF system might contribute to the adaptation to altered gravity in terms of spatial memory. Show more

Keywords: Spatial memory, hippocampus, vestibular system, insulin-like growth factor, microarray, PCR, cortisol, stress

DOI: 10.3233/VES-170521

Citation: Journal of Vestibular Research, vol. 27, no. 4, pp. 209-215, 2017

Authors: Kalicinski, Michael | Bock, Otmar | Schott, Nadja

Article Type: Research Article

Abstract: BACKGROUND: Before participating in a space mission, astronauts undergo parabolic-flight and underwater training to facilitate their subsequent adaptation to weightlessness. A quick, simple and inexpensive alternative could be training by motor imagery (MI). OBJECTIVE: An important prerequisite for this training approach is that humans are able to imagine movements which are unfamiliar, since they can’t be performed in the presence of gravity. Our study addresses this prerequisite. METHODS: 68 young subjects completed a modified version of the CMI test (Schott, 2013). With eyes closed, subjects were asked to imagine moving their body according to six consecutive …verbal instructions. After the sixth instruction, subjects opened their eyes and arranged the segments of a manikin into the assumed final body configuration. In a first condition, subjects received instructions only for moving individual body segments (CMIground ). In a second condition, subjects received instructions for moving body segments or their full body (CMIfloat ). After each condition, subjects were asked to rate their subjective visual and kinesthetic vividness of MI. RESULTS: Condition differences emerged for the CMI scores and for the duration of correct trials with better performance in the CMIground condition. Condition differences were also represented for the subjective MI performance. CONCLUSION: Motor imagery is possible but degraded when subjects are asked to imagine body movements while floating. This confirms that preflight training of MI while floating might be beneficial for astronauts’ mission performance. Show more

Keywords: Mental practice, body rotation, controllability, preflight training

DOI: 10.3233/VES-170621

Citation: Journal of Vestibular Research, vol. 27, no. 4, pp. 217-223, 2017

Authors: Alharbi, Ahmad A. | Johnson, Eric G. | Albalwi, Abdulaziz A. | Daher, Noha S. | Cordett, Tim K. | Ambode, Oluwaseun I. | Alshehri, Fahad H.

Article Type: Research Article

Abstract: BACKGROUND: Chronic motion sensitivity (CMS) has been defined as a feeling of un-wellness elicited by either actual or perceived motion. CMS is a common condition and is more prevalent in females than in males. In addition to a variety of symptoms, young adults with CMS have less postural stability than those without CMS. OBJECTIVE: To determine whether dependence on visual cues for postural stability is different between young adults with and without CMS, and whether it differs by gender within each group. METHODS: Sixty young adults (30 females and 30 males) were assigned to one of …two groups (CMS or non-CMS) using the Motion Sickness Susceptibility Questionnaire-Short Form. Postural stability was measured for all participants using the Bertec Balance Advantage–Computerized Dynamic Posturography with Immersion Virtual Reality. RESULTS: A significant difference was found in mean postural stability scores during immersion virtual reality between the CMS and non-CMS groups (p  < 0.001); however, no significant difference was shown in mean postural stability between males and females within the CMS and non-CMS groups (p  = 0.10 and p  = 0.97, respectively). CONCLUSION: The results suggest that young adults with CMS are over-reliant on visual cues for postural stability, and that visual dependence is not influenced by gender. Show more

Keywords: Motion sensitivity, vestibular system integrity, visual input, postural stability

DOI: 10.3233/VES-170534

Citation: Journal of Vestibular Research, vol. 27, no. 4, pp. 225-231, 2017

Authors: Guler, Ayse | Karbek Akarca, Funda | Eraslan, Cenk | Tarhan, Ceyda | Bilgen, Cem | Kirazli, Tayfun | Celebisoy, Nese

Article Type: Research Article

Abstract: INTRODUCTION: Head impulse test (HIT) is the critical bedside examination which differentiates vestibular neuritis (VN) from posterior circulation stroke (PCS) in acute vestibular syndrome (AVS). Video-oculography based HIT (vHIT) may have aadditional strength in making the differentiation. METHODS: Patients admitted to the emergency department of a tertiary-care medical center with AVS were studied. An emergency specialist and a neurologist performed HIT. vHIT was conducted by an neuro-otology research fellow. RESULTS: Forty patients 26 male, 14 female with a mean age of 49 years were included in the analyses. Final diagnoses were VN in 24 and PCS …in 16 patients. In the VN group, clinical HIT was assessed as abnormal in 19(80%) cases by the emergency specialist and in 20(83%) by the neurologist. In all PCS patients, HIT was recorded as normal both by the emergency specialist and the neurologist (100%). On vHIT, patients with VN had significantly low gain values for both the ipsilesional and contralesional sides when compared with the healthy controls, with significantly lower figures for the ipsilesional side (p  < 0.001). All patients in this group had normal DWI-MRI. PCS patients had bilaterally low gain (p  < 0.05) on vHIT. However, gain asymmetry was not significant. Subgroup analyses according to presence of brainstem involvement revealed bilateral low gain (p  < 0.05) in patients with brainstem infarction (anterior inferior cerebellar artery-posterior inferior cerebellar artery stroke, AICA-PICA stroke) whereas patients with pure cerebellar infarction (posterior inferior cerebellar artery-superior cerebellar artery stroke, PICA-SCA stroke) had gain values similar to healthy controls. With a gain cut-off ≤0.75 and gain asymmetry cut-off ≥17%, as determined by ROC analysis, 100% of PCS patients and 80% of VN patients were correctly diagnosed. CONCLUSIONS: Clinical HIT, either performed by an emergency specialist or neurologist is equivalent to vHIT gain and gain asymmetry analysis as conducted by neuro-otologist in the diagnosis of PCS, albeit mislabeling about 20% of VN patients. vHIT does not appear to yield additional diagnostic information. These findings indicate the strength of clinical HIT. Pure gain-based vHIT analysis seems limited and needs to be incorporated with saccade analysis. Show more

Keywords: Acute vestibular syndrome, head impulse test, video-oculography based head impulse test, vestibular neuritis, posterior circulation stroke

DOI: 10.3233/VES-170620

Citation: Journal of Vestibular Research, vol. 27, no. 4, pp. 233-242, 2017