μVEMP: A Portable Interface to Record Vestibular Evoked Myogenic Potentials (VEMPs) With a Smart Phone or Tablet

Background: Cervical VEMPs and ocular VEMPs are tests for evaluating otolith function in clinical practice. We developed a simple, portable and affordable device to record VEMP responses on patients, named μVEMP. Our aim was to validate and field test the new μVEMP device.Methods: We recorded cervical VEMPs and ocular VEMPs in response to bone conducted vibration using taps tendon hammer to the forehead (Fz) and to air conducted sounds using clicks. We simultaneously recorded VEMP responses (same subject, same electrode, same stimuli) in three healthy volunteers (2 females, age range: 29–57 years) with the μVEMP device and with a standard research grade commercial (CED) system used in clinics. We also used the μVEMP device to record VEMP responses from six patients (6 females, age mean±SD: 50.3 ± 20.8 years) with classical peripheral audio-vestibular diseases (unilateral vestibular neuritis, unilateral neurectomy, bilateral vestibular loss, unilateral superior canal dehiscence, unilateral otosclerosis).Results: The first part of this paper compared the devices using simultaneous recordings. The average of the concordance correlation coefficient was rc = 0.997 ± 0.003 showing a strong similarity between the measures. VEMP responses recorded with the μVEMP device on patients with audio-vestibular diseases were similar to those typically found in the literature.Conclusions: We developed, validated and field tested a new device to record ocular and cervical VEMPs in response to sound and vibration.This new device is portable (powered by a phone or tablet) with pocket-size dimensions (105 × 66 × 27 mm) and light weight (150 g). Although further studies and normative data are required, our μVEMP device is simpler (easier to use) and potentially more accessible than standard, commercially available equipment

Investigating the use of Virtual Reality in teaching chemistry to undergraduate students

Virtual Reality (VR) has become a much more common household commodity thanks to the proliferation of more affordable VR devices. Whilst its use in the gaming industry is widespread, its application in pedagogical environments is underdeveloped, particularly in chemistry. Hence, whether VR will aid or hinder the teaching and learning of chemistry is currently a topic of research and debate (Won, Mocerino, Tang, Treagust & Tasker, 2019). This project seeks to generate a range of VR materials designed to support students learning undergraduate chemistry, with the specific topics decided in consultation with undergraduate student researchers and various academic members of staff. This work is being undertaken in the X-reality (i.e. VR and other forms of augmented realities) laboratories of the Faculty of Science at the University of Sydney. Preliminary materials are being generated and will pilot tested with both students and teaching staff, with all data being audio recorded using a think-aloud protocol. Follow up interviews will also be conducted with all participants. Student understanding will then be tested with common theoretical questions and concept inventories. The results of these trails will be discussed and their implications on the use of VR in the teaching and learning of chemistry considered

An Attempt of Early Detection of Poor Outcome after Whiplash

The main concern with whiplash is that a large proportion of whiplash patients experience disabling symptoms or whiplash-associated disorders (WAD) for months if not years following the accident. Therefore, identifying early prognostic factors of WAD development is important as WAD have widespread clinical and economic consequences. In order to tackle that question, our study was specifically aimed at combining several methods of investigation in the same WAD patients at the acute stage and 6 months later. Our longitudinal, open, prospective, multi-center study included 38 whiplash patients, and 13 healthy volunteers matched for age, gender, and socio-economic status with the whiplash group. Whiplash patients were evaluated 15–21 days after road accident, and 6 months later. At each appointment, patients underwent a neuropsychological evaluation, a full clinical neurological examination, neurophysiological and postural tests, oto-neurological tests, cervical spine cord magnetic resonance imaging (MRI) with tractography (DTI). At 6 months, whiplash patients were categorized into two subgroups based on the results of the Diagnostic and Statistical Manual of Mental Disorders as having either favorable or unfavorable progression [an unfavorable classification corresponding to the presence of post-concussion symptom (PCS)] and we searched retrospectively for early prognostic factors of WAD predicting the passage to chronicity. We found that patients displaying high level of catastrophizing at the acute stage and/or post-traumatic stress disorder associated with either abnormalities in head or trunk kinematics, abnormal test of the otolithic function and at the Equitest or a combination of these syndromes, turned to chronicity. This study suggests that low-grade whiplash patients should be submitted as early as possible after the trauma to neuropsychological and motor control tests in a specialized consultation. In addition, they should be evaluated by a neuro-otologist for a detailed examination of vestibular functions, which should include cervical vestibular evoked myogenic potential. Then, if diagnosed at risk of WAD, these patients should be subjected to an intensive preventive rehabilitation program, including vestibular rehabilitation if required.This study was funded by the French Fondation Sécurité Routièr

An Initial Passive Phase That Limits the Time to Recover and Emphasizes the Role of Proprioceptive Information

In the present experiments, multiple balance perturbations were provided by unpredictable support-surface translations in various directions and velocities. The aim of this study was to distinguish the passive and the active phases during the pre-impact period of a fall. It was hypothesized that it should be feasible if one uses a specific quantitative kinematic analysis to evaluate the dispersion of the body segments trajectories across trials. Moreover, a multi-joint kinematical model was created for each subject, based on a new 3-D minimally invasive stereoradiographic X-ray images to assess subject-specific geometry and inertial parameters. The simulations allowed discriminating between the contributions of the passive (inertia-induced properties) and the active (neuromuscular response) components during falls. Our data show that there is limited time to adjust the way one fall from a standing position. We showed that the pre-impact period is truncated of 200 ms. During the initial part of a fall, the observed trajectory results from the interaction between the destabilizing external force and the body: inertial properties intrinsic to joints, ligaments and musculotendinous system have then a major contribution, as suggested for the regulation of static upright stance. This passive phase is later followed by an active phase, which consists of a corrective response to the postural perturbation. We believe that during a fall from standing height, it takes about 300 ms for postural responses to start correcting the body trajectory, while the impact is expected to occur around 700 ms. It has been argued that this time is sufficient to change the way one falls and that this makes it possible to apply safer ways of falling, for example by using martial arts fall techniques. Also, our results imply visual and vestibular information are not congruent with the beginning of the on-going fall. This consequence is to be noted as subjects prepare to the impact on the basis of sensory information, which would be uniquely mainly of proprioceptive origin at the fall onset. One limitation of the present analysis is that no EMG was included so far but these data are the subject of a future study

Postural instability in seniors : peripheral or central vestibular dysfunction?

L’instabilité posturale est fréquente chez les séniors et peut entrainer la chute. La chute chez les séniors est un problème majeur de santé publique. Les chiffres épidémiologiques sont éloquents : une personne sur trois âgées de plus de 70 ans fera une chute dans l’année. Les causes sont multifactorielles : ostéo-articulaire, visuelle, cognitive, vestibulaire…. Dans cette étude, nous nous sommes intéressés à l’évolution de la fonction des récepteurs vestibulaires périphériques avec l’âge et à la perception de rotation à partir des entrées canalaires horizontales (système vestibulaire central et projections vestibulaires corticales). Notre but est d’essayer de comprendre l’implication du vieillissement du système vestibulaire dans l’instabilité posturale des séniors. Au niveau périphérique, nous avons quantifié la fonction des canaux semi-circulaires horizontaux par le test calorique et le vidéo-head impulse test. La fonction des récepteurs otolithiques (utriculaire et sacculaire) a été évaluée par les potentiels évoqués myogéniques recueillis au niveau cervical (voies sacculo-spinales) et oculaire (voies utriculo-oculaires). Au niveau central, la perception de l’entrée vestibulaire canalaire horizontale a été appréciée après irrigation à l’eau chaude du conduit auditif externe en appliquant un score de perception (présence ou absence de sensation rotatoire). Finalement, l’équilibre a été quantifié grâce au test d’organisation sensorielle sur l’Equitest et grâce à un système que nous avons récemment mis au point en collaboration avec le Professeur Curthoys à Sydney, comprenant une Wii Balance Board, un tapis mousse et un masque de réalité virtuelle (Oculus Rift). Les résultats ont montré une diminution des réponses oculaires au test calorique après 70 ans mais une absence de baisse du gain du réflexe vestibulo-oculaire horizontal au vidéo-head impulse test. La fonction otolithique, sacculaire et utriculaire, est altérée avec l’âge quelle que soit la stimulation utilisée (aérienne ou osseuse). La perception de l’entrée vestibulaire canalaire horizontale induite par une stimulation calorique nous a permis de montrer pour la première fois que certains séniors ne percevaient pas la sensation de rotation malgré une réponse oculaire normale (vitesse maximale de la phase lente du nystagmus oculaire supérieure à 15°/s). Dans notre population, nous avons pu ainsi définir deux types de séniors : un groupe présentant une perception de vertige rotatoire et un groupe « négligeant » ne pouvant pas reconstruire une sensation rotatoire à partir des entrées vestibulaires canalaires horizontales. La comparaison de ces deux groupes de séniors appariés sur l’âge ne montre aucune différence de la fonction canalaire horizontale ni de la fonction otolithique sacculaire et utriculaire. Néanmoins, les séniors négligents présentent en majorité des performances anormales (chute ou score diminué) à l’Equitest notamment en conditions 5 et 6. De plus, leur score au DHI est plus élevé relevant ainsi le handicape ressenti par ces séniors à cause de leur instabilité. En conclusion, les troubles de l’équilibre chez certains seniors pourraient résulter en partie d’une dysfonction vestibulaire centrale. Des études ultérieures permettront de déterminer si l’augmentation du seuil de perception rotatoire est un bon facteur prédictif du risque de chute.Postural instability is common in seniors and can lead to falls which seniors are a major problem for Public Health. Epidemiological studies clearly show the magnitude of this problem: one in three people aged than more 70 years will fall in a year. This is caused by multiple factors including: musculoskeletal, visual, cognition, vestibular… The present study concerns the effect of age on the vestibular peripheral receptors function and on the perception of rotation from horizontal canal inputs (central vestibular processing and vestibular cortical projection). The aim is to try to understand the vestibular mechanisms involved in postural instability and mobility with age. At the peripheral level, the horizontal canal function was assessed using caloric test and video-Head Impulse Test. Otolith function (saccular and utricular) was assessed using vestibular evoked myogenic potentials recorded at cervical level (sacculo-spinal pathways) and at ocular level (utriculo-ocular pathways). At the central level, perception of motion from vestibular horizontal canal inputs was studied after caloric stimulation with warm water using a subjective perceptual score (presence or absence of rotatory vertigo). Finally, postural equilibrium was assessed with the Sensory Organization Test on the Equitest machine and also with a new system developed in collaboration with Prof. Curthoys (Sydney) using a Wii Balance Board, a foam rubber pad and a virtual reality headset (Oculus Rift DK2). Results showed decreased ocular responses induced by caloric stimulation after 70 years of age but healthy horizontal gain of the vestibulo-ocular reflex assessed by video-head impulse testing. The otolithic (saccular and utricular) function is impaired with age for all the stimuli used (air or bone conducted). Perception of motion induced by caloric stimulation (vestibular horizontal canal inputs) allowed us to show for the first time that some seniors are unable to feel the induced rotatory vertigo even with normal ocular responses (peak of the slow phase eye velocity higher than 15°/s). We defined two types of seniors: one senior group having a normal feeling of vertigo and one senior ‘neglect’ group who did not feel any sensation of rotation from horizontal canal inputs. The comparison of these two age-matched groups showed no difference in horizontal canal function, or otolithic function. The majority of the ‘neglect’ seniors with an absence of perception exhibited falls or a decreased score in conditions 5 and 6 during the Equitest. Moreover, their DHI scores were higher, showing the handicap induced by postural instability in these seniors. In conclusion, postural instability and falls in seniors may result from central vestibular impairment (inadequate central processing). A prospective study is needed to determine whether the increase perceptual threshold of rotation could be a good predictor of fall risk in seniors

Utility of vestibular testing and new technologies in a complex cholesteatoma

This paper reports a patient with a large recidivist cholesteatoma who underwent audio-vestibular tests and used customized 3D technologies (3D printing, augmented reality, virtual reality) to understand risks of the surgery. The patient was extremely concerned with her clinical findings and it found difficult to understand them. Customized 3D models helped the patient to understand the spatial relations and possible complications of surgery. The benefits of using new technologies in preoperative surgical planning for the surgeon and patient are also explained in a setting when radiological findings indicate high risks for surgery. Computed tomography scan showed a posterior semicircular canal fistula, which would add a significant challenge to the surgery. The fistula was not found in the result of the physiological test (cervical vestibular evoked myogenic potentials) and not found intra-operatively. Application of modern audio-vestibular investigations and use of customized 3D technologies may prove useful aids

The role of cervical and ocular vestibular evoked myogenic potentials in the assessment of patients with vestibular schwannomas.

OBJECTIVES: To investigate the clinical utility of VEMPs in patients suffering from unilateral vestibular schwannoma (VS) and to determine the optimal stimulation parameter (air conducted sound, bone conducted vibration) for evaluating the function of the vestibular nerve. METHODS: Data were obtained in 63 patients with non-operated VS, and 20 patients operated on VS. Vestibular function was assessed by caloric, cervical and ocular VEMP testing. 37/63 patients with conclusive ACS ocular VEMPs responses were studied separately. RESULTS: In the 63 non-operated VS patients, cVEMPs were abnormal in 65.1% of patients in response to AC STB and in 49.2% of patients to AC clicks. In the 37/63 patients with positive responses from the unaffected side, oVEMPs were abnormal in 75.7% of patients with ACS, in 67.6% with AFz and in 56.8% with mastoid BCV stimulation. In 16% of the patients, VEMPs were the only abnormal test (normal caloric and normal hearing). Among the 26 patients who did not show oVEMP responses on either side with ACS, oVEMPs responses could be obtained with AFz (50%) and with mastoid stimulation (89%). CONCLUSIONS: The VEMP test demonstrated significant clinical value as it yielded the only abnormal test results in some patients suffering from a unilateral vestibular schwannoma. For oVEMPs, we suggest that ACS stimulation should be the initial test. In patients who responded to ACS and who had normal responses, BCV was not required. In patients with abnormal responses on the affected side using ACS, BCV at AFz should be used to confirm abnormal function of the superior vestibular nerve. In patients who exhibited no responses on either side to ACS, BCV was the only approach allowing assessment of the function of the superior vestibular nerve. We favor using AFz stimulation first because it is easier to perform in clinical practice than mastoid stimulation

Image_2_μVEMP: A Portable Interface to Record Vestibular Evoked Myogenic Potentials (VEMPs) With a Smart Phone or Tablet.JPEG

<p>Background: Cervical VEMPs and ocular VEMPs are tests for evaluating otolith function in clinical practice. We developed a simple, portable and affordable device to record VEMP responses on patients, named μVEMP. Our aim was to validate and field test the new μVEMP device.</p><p>Methods: We recorded cervical VEMPs and ocular VEMPs in response to bone conducted vibration using taps tendon hammer to the forehead (Fz) and to air conducted sounds using clicks. We simultaneously recorded VEMP responses (same subject, same electrode, same stimuli) in three healthy volunteers (2 females, age range: 29–57 years) with the μVEMP device and with a standard research grade commercial (CED) system used in clinics. We also used the μVEMP device to record VEMP responses from six patients (6 females, age mean±SD: 50.3 ± 20.8 years) with classical peripheral audio-vestibular diseases (unilateral vestibular neuritis, unilateral neurectomy, bilateral vestibular loss, unilateral superior canal dehiscence, unilateral otosclerosis).</p><p>Results: The first part of this paper compared the devices using simultaneous recordings. The average of the concordance correlation coefficient was rc = 0.997 ± 0.003 showing a strong similarity between the measures. VEMP responses recorded with the μVEMP device on patients with audio-vestibular diseases were similar to those typically found in the literature.</p><p>Conclusions: We developed, validated and field tested a new device to record ocular and cervical VEMPs in response to sound and vibration.This new device is portable (powered by a phone or tablet) with pocket-size dimensions (105 × 66 × 27 mm) and light weight (150 g). Although further studies and normative data are required, our μVEMP device is simpler (easier to use) and potentially more accessible than standard, commercially available equipment.</p