Journal of Vestibular Research - Volume Pre-press, issue Pre-press

Authors: Sivarasan, Nishanth | Touska, Philip | Murdin, Louisa | Connor, Steve

Article Type: Research Article

Abstract: BACKGROUND/OBJECTIVES: Vestibular paroxysmia (VP) presents as episodic vertigo believed to be caused by neurovascular cross-compression (NVCC) of the vestibulocochlear nerve. We investigated whether NVCC occurred at a higher rate in VP, compared with controls and whether angulation of the nerve, the vessel involved and location of the point of contact were significant features. METHODS: Retrospective analysis was conducted of MR imaging performed in patients with VP and also patients with unilateral tinnitus (in whom the asymptomatic side was used as a control). Two independent, blinded reviewers assessed each case. RESULTS: Nine patients with VP and 20 …patients with unilateral tinnitus were included. NVCC was demonstrated in all 9 VP patients (100% ), compared with 9 of the controls (45% ), p  = 0.0049. NVCC was mostly caused by a branch of the anterior inferior cerebellar artery (AICA). Nerve angulation at the point of contact occurred in 5 of the cases (44% ), but in none of the controls (specificity = 100% ), p  = 0.0053. There was no correlation between site of contact and VP. CONCLUSION: Our study supports the concept of NVCC in VP and additionally suggests that nerve angulation may be a specific feature. Neurovascular contact remains a common phenomenon in asymptomatic patients and therefore correlation with neuro-otology assessment remains essential. Show more

DOI: 10.3233/VES-180661

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-9, 2019

Authors: Lopez-Escamez, Jose A. | Attyé, Arnaud

Article Type: Research Article

DOI: 10.3233/VES-180663

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-4, 2019

Authors: Nehrujee, Aravind | Vasanthan, Lenny | Lepcha, Anjali | Balasubramanian, Sivakumar

Article Type: Research Article

Abstract: BACKGROUND Vestibular dysfunctions result in a wide range of impairments and can have debilitating consequences on a person’s day-to-day activities. Conventional vestibular rehabilitation is effective but suffers from poor therapy compliance due to boredom. Virtual reality technology can make training more engaging and allow precise quantification of the training process. However, most existing technologies for vestibular rehabilitation are expensive and not suitable for use in patients’ homes and most clinics. In this pilot study, we developed and evaluated the usability of a smartphone-based head-mounted display (HMD) for vestibular rehabilitation and quantified the simulator sickness induced by the system. …METHODS Two adaptive training games were developed to train discrete and rhythmic head movements in the pitch and yaw planes. The usability and simulator sickness associated with the system were evaluated in a single testing session on healthy subjects and patients with unilateral vestibular dysfunction. Additionally, the head movement kinematics measured during training was also analyzed using different movement quality measures. RESULTS A total of 15 healthy subjects and 15 patients underwent testing with the system. Both groups found the system to be highly usable (>80 score on the system usability scale). Following 20–30 min training with the system, healthy subjects reported minimal simulator sickness symptoms. On the other hand, patients reported a higher incidence rate for symptoms, which could have been the result of their vestibular condition. CONCLUSION The current study demonstrated the usability and safety of a smartphone-based system for vestibular rehabilitation. The system is compact, and affordable thus has the potential to become an excellent tool for home-based vestibular rehabilitation. Show more

Keywords: Vestibular rehabilitation, virtual reality, smartphone, usability, head-mounted display, The trial was retrospectively registered with the Clinical Trials Registry - India (Registration number: CTRI/2017/05/008475).

DOI: 10.3233/VES-180660

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-14, 2019

Authors: N. Bretl, Kathrine | McCusker, Aaron T. | Sherman, Sage O. | Mitchell, Thomas R. | Dixon, Jordan B. | Clark, Torin K.

Article Type: Research Article

Abstract: BACKGROUND Artificial gravity (AG) has the potential to provide a comprehensive countermeasure mitigating deleterious effects of microgravity. However, the cross-coupled “Coriolis” illusion has prevented using a more feasible and less costly short-radius centrifuge, as compared to large, slowly spinning systems. OBJECTIVE We assessed tolerability of a personalized, incremental protocol to acclimate humans to the cross-coupled illusion, enabling faster spin rates. METHODS Ten subjects were exposed to the illusion by performing roll head tilts while seated upright and spun about an Earth-vertical axis. The spin rate was incremented when head tilts did not subjectively elicit the illusion. …Subjects completed one 25-minute session on each of 10 days. RESULTS The spin rate at which subjects felt no cross-coupled illusion increased in all subjects from an average of 1.8 rotations per minute (RPM) (SD: ±0.9) at the beginning of the protocol to 17.7 RPM (SD: ±9.1) at the end. For off-axis centrifugation producing 1G at the rider’s feet, this corresponds to a reduction in the required centrifuge diameter from 552.2 to 5.7 meters. Subjects reported no more than slight motion sickness. CONCLUSIONS Acclimation to the cross-coupled illusion, such as that accomplished here, is critical for feasibility of short-radius centrifugation for AG implementation. Show more

Keywords: Artificial gravity, short-radius centrifuge, physiological countermeasure

DOI: 10.3233/VES-180656

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-14, 2019

Authors: Gürkov, Robert

Article Type: Research Article

DOI: 10.3233/VES-180662

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-7, 2019

Authors: Kim, Hyun Ah | Bisdorff, Alexandre | Bronstein, Adolfo M. | Lempert, Thomas | Rossi-Izquierdo, Marcos | Staab, Jeffrey P. | Strupp, Michael | Kim, Ji-Soo

Article Type: Research Article

Abstract: This paper presents the diagnostic criteria for hemodynamic orthostatic dizziness/vertigo to be included in the International Classification of Vestibular Disorders (ICVD). The aim of defining diagnostic criteria of hemodynamic orthostatic dizziness/vertigo is to help the clinicians to understand the terminology related to orthostatic dizziness/vertigo and to distinguish orthostatic dizziness/vertigo due to global brain hypoperfusion from that caused by other etiologies. Diagnosis of hemodynamic orthostatic dizziness/vertigo requires: A) one or more episodes of dizziness/vertigo or unsteadiness triggered by arising or present during upright position, which subsides by sitting or lying down; B) orthostatic hypotension, postural tachycardia syndrome or syncope documented on …standing or during head-up tilt test; and C) not better accounted for by another disease or disorder. Probable hemodynamic orthostatic dizziness/vertigo is defined as follows: A) at least 5 episodes of dizziness/vertigo or unsteadiness triggered by arising or present during upright position, which subsides by sitting or lying down; B) at least one of the following accompanying symptoms: generalized weakness/tiredness, difficulty of thinking/concentration, blurred vision, and tachycardia/palpitations; and C) not better accounted for by another disease or disorder. These diagnostic criteria have been derived by expert consensus from an extensive review of 90 years of research on hemodynamic orthostatic dizziness/vertigo, postural hypotension or tachycardia, and autonomic dizziness. Measurements of orthostatic blood pressure and heart rate are important for the screening and documentation of orthostatic hypotension or postural tachycardia syndrome to establish the diagnosis of hemodynamic orthostatic dizziness/vertigo. Show more

Keywords: Orthostatic vertigo, classification, orthostatic dizziness, hemodynamic, autonomic dysfunction, orthostatic hypotension, postural tachycardia syndrome, Bàràny Society

DOI: 10.3233/VES-190655

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-12, 2019

Authors: Aplin, F.P. | Singh, D. | Santina, C.C. Della | Fridman, G.Y.

Article Type: Research Article

Abstract: BACKGROUND: Vestibular prostheses emulate normal vestibular function by electrically stimulating the semicircular canals using pulse frequency modulation (PFM). Spontaneous activity at the vestibular nerve may limit the dynamic range elicited by PFM. One proposed solution is the co-application of ionic direct current (iDC) to inhibit this spontaneous activity. OBJECTIVE: We aimed to test the hypothesis that a tonic iDC baseline delivered in conjunction with PFM to the vestibular semicircular canals could improve the dynamic range of evoked eye responses. METHODS: Gentamicin-treated chinchillas were implanted with microcatheter electrodes in the vestibular semicircular canals through which pulsatile and …iDC current was delivered. PFM was used to modulate vestibulo-ocular reflex (VOR) once it was adapted to a preset iDC and pulse-frequency baseline. Responses to stimulation were assessed by recording the evoked VOR eye direction and velocity. RESULTS: PFM produced VOR responses aligned to the stimulated canal. Introduction of an iDC baseline lead to a small but statistically significant increase in eye response velocity, without influencing the direction of eye rotation. CONCLUSIONS: Tonic iDC baselines increase the dynamic range of encoding head velocity evoked by pulsatile stimulation, potentially via the inhibition of spontaneous activity in the vestibular nerve. Show more

Keywords: Vestibular system, vestibular prosthesis, electrical stimulation, vestibulo-ocular reflex, neural implant, direct current

DOI: 10.3233/VES-190651

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-8, 2019

Authors: Jáuregui-Renaud, Kathrine | Aranda-Moreno, Catalina | Villaseñor-Moreno, Julio C. | Giráldez Fernández, María E. | Maldonado Cano, Abraham Jesús | Gutierrez Castañeda, Martha F. | Figueroa-Padilla, Ignacio | Saucedo-Zainos, Ana L.

Article Type: Research Article

Abstract: BACKGROUND: A recent study has shown variability on the perception of verticality during unilateral centrifugation among patients with type 2 diabetes mellitus; it is yet unknown if it is related to symptoms of unreality. OBJECTIVE: In patients with type 2 diabetes mellitus compared to age matched healthy volunteers, to assess depersonalization/derealization (DD) symptoms before and after unilateral centrifugation, according to the subjective visual vertical (SVV). METHODS: 47 patients with type 2 diabetes mellitus and 50 age matched healthy volunteers participated in the study. They replied to standardized questionnaires of symptoms related to balance, depression, and anxiety. …Then, after neuro-otological evaluation, they completed a DD inventory before and after unilateral centrifugation (300°/s, 3.85 cm) with SVV estimation. RESULTS: Right/left asymmetric SVV during centrifugation was identified in 17 patients (36%) and no SVV change during centrifugation was identified in 6 patients (13%). Before centrifugation, patients with asymmetric SVV already reported some of the DD symptoms, while patients with no SVV change reported almost no DD symptoms. Unilateral centrifugation provoked an increase of DD symptoms in both healthy volunteers and the entire group of patients (repeated measures ANOVA, p  <  0.01), except in the 6 patients with no SVV change. Before centrifugation, the DD score showed influence from the SVV subgroup and the evidence of depression (MANCoVA, p  <  0.01); after centrifugation, which provoked asymmetry of the right/left utricular input, only the influence from depression persisted. No influence was observed from the characteristics of the subjects, including retinopathy, peripheral neuropathy (assessed by electromyography) or weight loss, or from the total score on the questionnaire of symptoms related to balance. CONCLUSIONS: In patients with type 2 diabetes mellitus and healthy volunteers, utricular stimulation by unilateral centrifugation may provoke DD symptoms, with an influence from depression. The results support that the aphysiological utricular input given by unilateral centrifugation may contribute to create a misleading vestibular frame of reference, giving rise to ‘unreal’ perceptions. Show more

Keywords: Depersonalization, derealization, diabetes mellitus, vestibular function, utricular macula

DOI: 10.3233/VES-190652

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-10, 2019

Authors: Lopez-Escamez, Jose A. | Attyé, Arnaud

Article Type: Research Article

Abstract: The diagnostic criteria for Meniere Disease (MD) are clinical and include two categories: definite MD and probable MD, based on clinical examination and without the necessity of advanced vestibular or audiological testing. The condition is a heterogeneous disorder and it is associated with endolymphatic hydrops (EH), an accumulation of endolymph in the inner ear that causes damage to the ganglion cells. Patients with suspected EH can be examined by Magnetic Resonance Imaging (MRI), offering new insights into these inner ear disorders. Results of imaging studies using the hydrops protocols show conflicting results in MD patients. These discrepancies can be dependent …either on the MRI sequence parameters or on the method of hydrops grading or the inclusion criteria to select patients. The visualization of EH can be classified based on a semi-quantitative ratio between endolymph and perilymph liquids, or on the distinction between the saccule and the utricle structures. In addition, MRI can also be used to evaluate whether cochleovestibular nerves can present with imaging signs of axonal loss. In this systematic review, we have selected case-controlled studies to better characterize the potential added value in the diagnosis and management of patients with MD. Using different techniques, studies have identified the saccule as the most specifically involved structure in MD, and saccular hydrops seems to be associated with low to medium-tone sensorineural hearing loss degree. However, early symptoms still appear too subtle for identification using MRI and the reproducibility of the hydrops protocols with various MRI scan manufacturers is debatable, thus limiting expansion of these techniques into clinical practice for the diagnosis of MD at this time. Further research is needed. The future inclusion of semicircular canal hydrops location in the imaging signs and the application of MRI in patients with atypical presentations hold promise. Show more

Keywords: Meniere’s disease, endolymphatic hydrops, Magnetic Resonance Imaging, contrast media injection

DOI: 10.3233/VES-180646

Citation: Journal of Vestibular Research, vol. Pre-press, no. Pre-press, pp. 1-9, 2018