Search

New tests of otolithic function use air conducted sound (ACS) and bone conducted vibration (BCV) as otolithic stimuli. These stimuli generate vestibular evoked myogenic potentials (VEMPs) from tens...

Purpose:The aim of this systematic review was to evaluate the clinical application potential of the video head impulse test (vHIT) in diagnosing vestibular neuritis (VN). Methods:An electronic search was conducted in the following databases: Embase, MEDLINE, ScienceDirect, Google scholar, and the Cochrane Database of Systematic Reviews. Clinical studies were included in which an evaluation was made using vHIT either alone or in combination with other tests or bedside algorithms. Evaluations that were carried out using unvalidated tools were excluded. Only studies of patients with VN (superior, inferior, or in toto) were included. Screening of titles, abstracts, full texts, and data extraction were undertaken independently by pairs of reviewers. Included studies were quality appraised using a modified version of the Newcastle-Ottawa scale. Results:Results were reported according to the preferred reporting items for systematic reviews and meta-analyses. Our search yielded 1309 unique records, 21 of which remained after screening titles and abstracts. Sixteen studies were included, i.e., for a total of 933 patients including 474 patients with a diagnosis of VN. Conclusions:The diagnostic value of vHIT is high for VN, as it is a high-frequency measurement tool. vHIT is a useful complement or alternative to caloric and rotational tests as an indicator of lesions of vestibular canal functioning, especially at the time of onset. This tool can provide useful clues about the clinical progress of recovery from the lesion through the value of the vestibulo ocular reflex gain and the consequent evolution of the saccade pattern, which allows the patient to stabilize vision on the retina.

Background: This review aims to explore the potential clinical application of the suppression head impulse paradigm (SHIMP) in patients with unilateral and bilateral vestibulopathy. Methods: An electronic search was conducted by two independent reviewers in the following databases: Embase, MEDLINE (PubMed), and Scopus. The screening of titles, abstracts, and full texts and data extraction were undertaken independently by pairs of reviewers. The included studies were quality appraised using a modified version of the Newcastle–Ottawa Scale. Results: The results were reported following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Our search yielded 935 unique records, of which 16 remained after screening titles and abstracts. A total of 11 studies were included, covering a total of 418 participants (230 patients and 188 healthy participants). Conclusion: SHIMP could be a useful tool to diagnose a VOR alteration in patients with vestibulopathy in both the acute and chronic phases of vestibulopathy.

OBJECTIVE: To evaluate the presence of anti-compensatory saccades (AcS) using the video head impulse test (vHIT) in the healthy inner ear in patients with vestibular neuritis (VN) during the acute and subacute stages of VN. METHODS: We retrospectively considered a chart review of 2420 patients evaluated for acute vestibular syndrome from 2016 to 2020 in the Cassino (Italy) clinic. Nine hundred fifty-four patients with acute onset of vestibular syndrome who received an instrumental otoneurological assessment within 24 hours from the onset of the symptoms, evaluated by simultaneously using a combination of vHIT, ocular vestibular-evoked myogenic potential (VEMP), and cervical VEMP, were included in the study. RESULTS: Thirty-two patients with superior VN that showed an altered horizontal canal function when tested with vHIT and quick AcS on the healthy side were enrolled. We found that all patients with VN, evaluated in the first 24 hours from the onset of the symptoms, showed AcS when their head was abruptly and passively turned toward the healthy inner ear side. At follow-up within 8 weeks from the first evaluation, 29 out of 32 patients did not show increased AcS. CONCLUSIONS: Our findings support the hypothesis that the AcS on the healthy side are a clinical sign of vestibular canal hypofunction or paresis in patients affected by the acute stage of VN

Introduction: On video head impulse testing (vHIT) of semicircular canal function, some patients reliably show enhanced eye velocity and so VOR gains >1.0. Modeling and imaging indicate this could be due to endolymphatic hydrops. Oral glycerol reduces membranous labyrinth volume and reduces cochlear symptoms of hydrops, so we tested whether oral glycerol reduced the enhanced vHIT eye velocity.Study Design: Prospective clinical study and retrospective analysis of patient data.Methods: Patients with enhanced eye velocity during horizontal vHIT were enrolled (n = 9, 17 ears) and given orally 86% glycerol, 1.5 mL/kg of body weight, dissolved 1:1 in physiological saline. Horizontal vHIT testing was performed before glycerol intake (time 0), then at intervals of 1, 2, and 3 h after the oral glycerol intake. Control patients with enhanced eye velocity (n = 4, 6 ears) received water and were tested at the same intervals. To provide an objective index of enhanced eye velocity we used a measure of VOR gain which captures the enhanced eye velocity which is so clear on inspecting the eye velocity records. We call this measure the initial VOR gain and it is defined as: (the ratio of peak eye velocity to the value of head velocity at the time of peak eye velocity). The responses of other patients who showed enhanced eye velocity during routine clinical testing were analyzed to try to identify how the enhancement occurred.Results: We found that oral glycerol caused, on average, a significant reduction in the enhanced eye velocity response, whereas water caused no systematic change. The enhanced eye velocity during the head impulses is due in some patients to a compensatory saccade-like response during the increasing head velocity.Conclusion: The significant reduction in enhanced eye velocity during head impulse testing following oral glycerol is consistent with the hypothesis that the enhanced eye velocity in vHIT may be caused by endolymphatic hydrops.

OBJECTIVES: We retrospectively evaluated a chart review of 3,525 patients evaluated for any acute disturbance. A total of 1,504 patients with acute vestibular syndrome (AVS) received an instrumental vestibular assessment within 72 h from the onset of the symptoms evaluated using simultaneously a combination of ocular vestibular-evoked myogenic potential (oVEMPs), cervical vestibular-evoked myogenic potential (cVEMPs), video head-impulse test (vHIT), and subjective visual vertical (SVV) were included in this study. MATERIALS and METHODS: A total of 41 patients with AVS that showed a normal horizontal canal function tested with vHIT, a normal cVEMP function, unilaterally reduced or absent oVEMP n10, and an altered SVV were enrolled. RESULTS: We found that although these patients referred acute vertigo and presented spontaneous nystagmus, they showed physiological values of vHIT and a normal saccular function, as shown by symmetrical cVEMPs. CONCLUSION: Our findings support the hypothesis that a percentage of patients evaluated during an AVS using an instrumental vestibular assessment could present selective utricular macula dysfunction

PurposeTime course of the recovery of otolithic dis-function caused by superior vestibular neuritis has been examined in fifteen patients.MethodsThe subjective visual vertical (SVV) and the ocular cyclotorsion (OT) have been measured four times after the acute episode up to 1 yearResultsIn most of the patients the SVV tilt returned to control values within few months (3–6 months) after the acute episode, while OT remained out of normal range in almost all patients a year later.ConclusionThe abnormal OT observed after 1 year from the acute episode of vestibular neuritis, suggests that the otolithic receptors remained altered for several months and the OT may be a good indicator of the entity of the residual peripheral otolithic lesion. Moreover, the dissociation between the SVV tilt recovery and that of OT supports the issue that the two signs of the otolithic disfunction are only partially linked each other with centrally or peripherally distinct re-balancing circuits.

Purpose:Evaluate the potential clinical application of the Suppression Head Impulse Paradigm (SHIMP) in evaluating the vestibulo-saccadic interaction in patients with vestibular neuritis (VN). Methods:A retrospective study was performed. Fifteen patients diagnosed with unilateral VN were identified from a database of ENT vestibular clinic from January 2011 to February 2020. Medical records were reviewed to determine clinical presentation, vestibular testing results, treatment, and recovery. Results:Fifteen patients (7 left ear, 8 right ear, mean age 58.73 ± 10.73, six female) met the inclusion criteria and were enrolled in the study. Significant differences were found in the within-subjects analysis at T1 in DHI score (p = 0.001), VOR gain (p < 0.005), and in the percentages of impulses containing a SHIMPs saccade when the head is passively turned toward the affected side (p = 0.001). Conclusions:SHIMPs paradigm provides useful information about the value of vestibulo-saccadic interaction as new recovery strategies in patients with VN

Objective: To review the theory, the validity and the clinical application and the new developments of the video head impulse test (vHIT) of semicircular canal function. vHIT has now superseded the caloric test as the first-line clinical test for vestibular patients.Outcomes: This review examines the origin and rationale for vHIT: how it is carried out; pitfalls in testing; the validation of the test; the interpretation of overt and covert compensatory saccades in patients with vestibular loss; how the area VOR gain is calculated.Results: The advantages of the test are considered: it is so innocuous that it can be given to patients even during acute vertigo attacks, and given repeatedly at short intervals; it is very successful for testing young children; it tests all six semicircular canals, and, unlike the caloric test, provides measures of the absolute level of canal function and so is valuable for monitoring the effect of ototoxic antibiotics as well as identifying bilateral vestibular loss. P...

Background:Cerebral palsy (CP) has been defined as a nonprogressive disease of movement and posture development. Physical therapy techniques use different forms of sensory stimulation to improve neuromotor development.Aim:The aim of this study was to assess the efficacy of a vestibular stimulation training in improving motor functions in cerebral palsy.Population:Fourteen children with CP were randomly separated into two different groups in a cross-over trial.Methods:Over a period of 10 weeks, each group performed 10 sessions of 50 min of neurodevelopmental treatment (NDT) and 10 sessions of vestibular training (VR). Children were evaluated with the Gross Motor Function Measurement-88 scale, the Goal Attainment Scale and the root mean square of head accelerations.Results:A significant improvement in the GAS-score (p = .003) was noted after NDT+VR.Conclusions:Vestibular stimulation integrated with NDT proved to be an effective complementary strategy for facilitating motor functioning.

Recent advances in vestibular testing now permit functional testing of all peripheral vestibular sense organs (all three semicircular canals, utricle, and saccule). This makes it possible to identify patients with isolated dysfunction of the utricle or saccule, even though parallel pathways for vestibular information are ultimately integrated centrally. Selective, isolated unilateral loss of utricular function as measured by ocular vestibular-evoked myogenic potentials (VEMPs) has been observed in patients with normal semicircular canal function as measured by the video head impulse test of all six semicircular canals, and normal bilateral saccular function as determined by symmetrical cervical VEMPs. How these patients present clinically and how they recover is discussed and contrasted with acute vestibular neuritis. In some patients, the unilateral loss of otolith organ (utricle or saccule) function persists and yet the patient recovers functionally to their usual lifestyle. Until the testing of all peripheral vestibular sense organs is routine, the frequency of isolated loss of otolith function cannot be gauged.

Air-conducted sound and bone-conduced vibration activate otolithic receptors and afferent neurons in both the utricular and saccular maculae, and trigger small electromyographic (EMG) responses [called vestibular-evoked myogenic potentials (VEMPs)] in various muscle groups throughout the body. The use of these VEMPs for clinical assessment of human otolithic function is built on the following logical steps: (1) that high-frequency sound and vibration at clinically effective stimulus levels activate otolithic receptors and afferents, rather than semicircular canal afferents, (2) that there is differential anatomical projection of otolith afferents to eye muscles and neck muscles, and (3) that isolated stimulation of the utricular macula induces short latency responses in eye muscles, and that isolated stimulation of the saccular macula induces short latency responses in neck motoneurons. Evidence supports these logical steps, and so VEMPs are increasingly being used for clinical assessment of otolith function, even differential evaluation of utricular and saccular function. The proposal, originally put forward by Curthoys in 2010, is now accepted: that the ocular vestibular-evoked myogenic potential reflects predominantly contralateral utricular function and the cervical vestibular-evoked myogenic potential reflects predominantly ipsilateral saccular function. So VEMPs can provide differential tests of utricular and saccular function, not because of stimulus selectivity for either of the two maculae, but by measuring responses which are predominantly determined by the differential neural projection of utricular as opposed to saccular neural information to various muscle groups. The major question which this review addresses is how the otolithic sensory system, with such a high density otoconial layer, can be activated by individual cycles of sound and vibration and show such tight locking of the timing of action potentials of single primary otolithic afferents to a particular phase angle of the stimulus cycle even at frequencies far above 1,000 Hz. The new explanation is that it is due to the otoliths acting as seismometers at high frequencies and accelerometers at low frequencies. VEMPs are an otolith-dominated response, but in a particular clinical condition, semicircular canal dehiscence, semicircular canal receptors are also activated by sound and vibration, and act to enhance the otolith-dominated VEMP responses.

We report enhanced symmetrical cervical vestibular evoked myogenic potential (cVEMP) but asymmetrical ocular VEMP (oVEMP) responses in a patient with CT-verified bilateral superior semicircular canal dehiscence (SCD) but with acute vestibular syndrome. This implies that absence of unilateral utricular macula function alone is sufficient to cause symptoms of acute vertigo. Acute vertigo should not automatically be presumed to originate from semicircular canal dysfunction.To identify the cause of an acute vertigo attack in a patient with bilateral SCD.The functional state of all peripheral vestibular sense organs was tested using the video head impulse test (vHIT) for all semicircular canals and VEMPs to air-conducted sound (ACS) or bone-conducted vibration (BCV) to test all otolith organs. The cVEMP tested mainly saccular function and the oVEMP mainly utricular function.All semicircular canals showed normal function. The cVEMPs showed enhanced, but symmetrical saccular function. In contrast, oVEMPs showed an enhanced but asymmetric n10 component - it was greatly reduced beneath the left eye, implying decreased function in the right utricular macula. That result was confirmed using very high frequency stimuli which are effective in SCD: 4000 Hz BCV stimuli showed that oVEMP n10 was present beneath the right eye but absent beneath the left eye.

Bilateral vestibulopathy (BVP) is a debilitating disorder characterized by the hypofunction of both vestibular end organs or nerves. The most frequent identifiable causes of BVP are ototoxic drug effects, infectious and autoimmune disorders. The majority of cases, however, remain idiopathic. Medical records of patients diagnosed with idiopathic BVP were examined in five dizziness clinics. We identified 126 patients with “idiopathic” BVP. Out of these, 15 patients had a history of Amiodarone treatment before the diagnosis of BVP, resulting in a 12% prevalence. The present report supports the hypothesis that Amiodarone can cause BVP. Vestibular examination in patients taking Amiodarone and suffering from balance-related symptoms are recommended, to recognize this adverse effect as early as possible and allow for an informed judgement on a potential dose reduction or withdrawal for recovery of the vestibular function.

Summary 1. Extracellular single neuron recording and labelling studies of primary v estibular afferents in Scarpa’ s ganglion have shown that guinea pig otolithic afferents with irregular resting discharge are preferentially acti vated by 500Hz bone-conducted vibration (BCV) and man ya lso by 500Hz air-conducted sound (ACS) at lo wt hreshold and high sensitivity .V ery fe wa fferent neurons from any semicircular canal are activated by these stimuli and then only at high intensity. 2. Tracing the origin of the acti vated neurons shows that these sensitive otolithic afferents originate mainly from as pecialized region ‐ the striola ‐ of both the utricular and saccular maculae. 3. This same 500Hz BCV elicits vestibulardependent eye mo vements in alert guinea pigs and also in health yh umans. These stimuli evoke myogenic potentials (VEMPs) which are used to test the function of the utricular and saccular maculae in human patients. 4. Although utricular and saccular afferents can both be activated by BCV and ACS, the differential projection of utricular and saccular afferents to dif ferent muscle groups allows for differentiation of the function of these tw o sensory regions. The basic neural data support the conclusion that in human patients in response to brief 500Hz BCV delivered to Fz (the midline of the forehead at the hairline) the cervical VEMP (cVEMP) indicates predominantly saccular function and the ocular VEMP (oVEMP) indicates predominantly utricular function. 5. The neural, anatomical and behavioural evidence underpins clinical tests of otolith function in humans using sound and vibration.

To measure horizontal semicircular canal function over days, weeks, and months after an acute attack of vestibular neuritis.The video head impulse test (vHIT) was used to measure the eye movement response to small unpredictable passive head turns at intervals after the attack.Two patients diagnosed with acute right unilateral vestibular neuritis.There was full restoration of horizontal canal function in one patient (A) as shown by the return of the slow phase eye velocity response to unpredictable head turns, while in the other patient (B) there was little or no recovery of horizontal canal function. Instead this second patient generated covert saccades during head turns.Despite the objective evidence of their very different recovery patterns, both patients reported, at the final test, being happy and feeling well recovered, even though in one of the patients there was clear absence of horizontal canal function. The results indicate covert saccades seem a successful way of compensating for loss of horizontal canal function after unilateral vestibular neuritis. Factors other than recovery of the slow phase eye velocity are significant for patient recovery.

Superior semicircular canal dehiscence and an abnormally wide internal auditory meatus are clinical entities characterized by vestibular and cochlear symptoms. These symptoms are induced by hypersensitivity of labyrinthine receptors secondary to a bone defect of the otic capsule. We report the case of a 41-year-old man with congenital right-sided hearing loss who presented with bilateral superior semicircular canal dehiscence that was associated with wide, bulbous internal auditory meatus and a loss of the bony wall separating the lateral end of the meatus from the cochlea. The patient was experiencing vestibular and cochlear symptoms in the right ear and disabling tinnitus in the left ear. However, he refused all treatment and was lost to follow-up.

While compensatory saccades indicate vestibular loss in the conventional head impulse test paradigm (HIMP), in which the participant fixates an earth-fixed target, we investigated a complementary suppression head impulse paradigm (SHIMP), in which the participant is fixating a head-fixed target to elicit anticompensatory saccades as a sign of vestibular function.HIMP and SHIMP eye movement responses were measured with the horizontal video head impulse test in patients with unilateral vestibular loss, patients with bilateral vestibular loss, and in healthy controls.Vestibulo-ocular reflex gains showed close correlation (R(2) = 0.97) with slightly lower SHIMP than HIMP gains (mean gain difference 0.06 ± 0.05 SD, p0.001). However, the 2 paradigms produced complementary catch-up saccade patterns: HIMP elicited compensatory saccades in patients but rarely in controls, whereas SHIMP elicited large anticompensatory saccades in controls, but smaller or no saccades in bilateral vestibular loss. Unilateral vestibular loss produced covert saccades in HIMP, but later and smaller saccades in SHIMP toward the affected side. Cumulative HIMP and SHIMP saccade amplitude differentiated patients from controls with high sensitivity and specificity.While compensatory saccades indicate vestibular loss in conventional HIMP, anticompensatory saccades in SHIMP using a head-fixed target indicate vestibular function. SHIMP saccades usually appear later than HIMP saccades, therefore being more salient to the naked eye and facilitating vestibulo-ocular reflex gain measurements. The new paradigm is intuitive and easy to explain to patients, and the SHIMP results complement those from the standard video head impulse test.This case-control study provides Class III evidence that SHIMP accurately identifies patients with unilateral or bilateral vestibulopathies.

Dear Sir,It is difficult to obtain objective measures of vestibularfunction from very young children (3- to 7-years-old)because they are unwilling to receive caloric tests whichinduce vertigo, or to undergo bedside examination forspontaneous nystagmus as they must be in darkness forsome minutes [1, 2]. It is also difficult to obtain an accuratemedical history in such young patients in a subacute stage,and in order to understand what really happened, the cli-nician relies on the story told by the parents. These diffi-culties increase when a child comes to a vertigo clinic or anEmergency Department in the acute stage of a vertigoattack complaining that the world is turning around. Underthese circumstances, a clinician can identify the classicalsigns and symptoms which are dependent on the absentfunction of the affected vestibular labyrinth. Such classicalstatic clinical signs are (a) spontaneous nystagmus with thequick phase of the horizontal component directed awayfrom the affected ear, (b) ocular torsion with both eyesrolled away from the affected ear indicating unilaterallyreduced otolithic function of the affected ear, (c) skewdeviation with a vertical misalignment between the twoeyes such that the ipsilesional eye shows a lower positionin the orbit, (d) postural instability with sensations offalling toward the lesioned side, related to reduced functionof the affected ear projecting to ipsilateral vestibulo-spinalresponses. The usual standard tests of dynamic vestibularfunction are (e) the Hallpike–Fitzgerald canal paresismeasure from caloric testing and (f) the clinical sign ofcanal paresis (the head-impulse sign)—during brief, pas-sive, unpredictable, horizontal head turns toward theaffected ear, the patient with reduced unilateral horizontalcanal function fails to maintain fixation on an earth-fixedtarget and so makes corrective (overt) saccades at the endof the head rotation in order to regain fixation [3]. Duringsimilar rotations toward the healthy ear no overt saccadesare evident. The overt saccade is a sign of reduced dynamichorizontal canal function; however, this clinical sign issubjective, in that there is no objective measure of the headvelocity stimulus or the eye velocity response and so noobjective measure of vestibulo-ocular (VOR) gain.Three new objective measures of dynamic vestibularfunction have been reported. These tests are quick, accurateand not demanding for the patients (i.e., they do not inducevertigo), and above all they can be used to obtain objectivemeasures of the dynamic function of all the vestibularreceptors, both semicircular canals and otoliths, even invery young children. Two of the tests use vestibular-evoked myogenic potentials to sound and vibration. Thefirst is the cervical vestibular-evoked myogenic potential(cVEMP) to air-conducted sound (ACS) or bone conductedvibration (BCV) [4, 5]. These stimuli have been shown topreferentially activate otolith irregular afferents from theutricular and saccular macula [5–7]. The cVEMP responseto ACS and BCV indicates dynamic saccular and inferiorvestibular nerve function. In healthy subjects with surfaceelectrodes on the tensed sternocleidomastoid muscles, it isfound that that in response to BCV or intense ACS stim-ulation there is a short-latency positive (inhibitory) poten-tial (p13-n23) at a latency of around 13 ms from stimulusonset, indicating ipsilateral saccular function. The second

Extracellular single neuron recordings of primary vestibular neurons in Scarpa's ganglion in guinea pigs show that low-intensity 500 Hz bone-conducted vibration (BCV) or 500 Hz air-conducted sound (ACS) activate a high proportion of otolith irregular neurons from the utricular and saccular maculae but few semicircular canal neurons. In alert guinea pigs, and humans, 500 Hz BCV elicits otolith-evoked eye movements. In humans, it also elicits a myogenic potential on tensed sternocleidomastoid muscles. Although BCV and ACS activate both utricular and saccular maculae, it is possible to probe the functional status of these two sense organs separately because of their differential neural projections. Saccular neurons have a strong projection to neck muscles and a weak projection to the oculomotor system. Utricular afferents have a strong projection to eye muscles. So measuring oculomotor responses to ACS and BCV predominantly probes utricular function, while measuring neck muscle responses to these stimuli predominantly probes saccular function.

The enhanced sound- and vibration-induced vestibular evoked myogenic potentials (VEMPs) and their lower threshold in patients with a thinning of the bony wall of the superior semicircular canal (superior canal dehiscence, SCD) have been interpreted as being due to the dehiscence allowing sound and vibration to activate, unusually, the receptors of the dehiscent semicircular canal. We report a patient with bilateral SCD, as verified by high resolution CT scans, who had bilaterally decreased superior semicircular canal function, as shown by rotational tests of canal function. This patient also showed enhanced VEMPs and reduced thresholds. We conclude that in this patient the enhanced VEMP responses are thus probably due to enhanced otolithic stimulation by sound and vibration after dehiscence.

Objective Two indicators of otolithic function were used to measure dynamic otolith function in the same patients both during an acute attack of Meniere’s disease (MD) and in the quiescent period between attacks. Methods The early negative component (n10) of the ocular vestibular-evoked myogenic potential (the oVEMP) to brief 500 Hz bone conducted vibration (BCV) stimulation of the forehead, in the midline at the hairline (Fz) was recorded by surface EMG electrodes just beneath both eyes while the patient looked up. It has been proposed that the n10 component of the oVEMP to 500 Hz Fz BCV indicates utricular function. It has been proposed that the early positive component (p13) of the cervical vestibular-evoked myogenic potential (the cVEMP) recorded by surface electrodes on both tensed SCM neck muscles to 500 Hz Fz BCV indicates saccular function. Results Sixteen healthy control subjects tested on two occasions showed no detectable change in the symmetry of oVEMPs or cVEMPs to 500 Hz Fz BCV. In response to 500 Hz Fz BCV 15 early MD patients tested at both attack and quiescent phases showed a dissociation: there was a significant increase in contralesional of n10 of the oVEMP during the attack compared to quiescence but a significant decrease in the ipsilesional p13 of the cVEMP during the attack compared to quiescence. Conclusions During an MD attack, dynamic utricular function in the affected ear as measured by the n10 of the oVEMP to 500 Hz Fz BCV is enhanced, whereas dynamic saccular function in the affected ear as measured by the p13 of the cVEMP to 500 Hz Fz BCV is not similarly affected. Significance The MD attack appears to affect different otolithic regions differentially.

The vestibular aqueduct is a bony canal related to the bony labyrinth of the inner ear and represents the non-sensory components of the endolymph-filled, closed, membranous labyrinth. The association of congenital sensorineural hearing loss with a large or enlarged vestibular aqueduct is well known as the large vestibular aqueduct syndrome (LVAS). The enlarged VA (EVA) comprises abnormalities not only in the structure of the inner ear, but also in the physiology of the auditory and vestibular systems. The clinical picture of this clinical entity is variable [Yetiser S, Kertment M, Ozkaptan Y. Vestibular disturbance in patients with Large Vestibular Aqueduct Syndrome (LVAS). Acta Otolaryngol (StochK) 1999;119: 641-646]. Signs and symptoms of the auditory impairment are more commonly described in the literature: hearing loss ranges from mild to profound, arising from fluctuating to stepwise progressive or sudden. Vestibular disturbances, ranging from mild imbalance to episodic vertigo, are rarely described in the literature. Benign paroxysmal positional vertigo (BPPV) is a labyrinthine disorder with a typical behavior: intense crises of rotational vertigo induced by postural changes of the head, with short duration and usually good responsiveness to rehabilitative maneuvers. These maneuvers are effective in about 80% of patients with BPPV. BPPV often recurs. About 1/3 of patients have a recurrence in the first year after treatment, and by five years, about half of all patients have a recurrence. Vestibular aqueduct has been demonstrated by conventional tomography and computed tomography (CT), however, CT scans cannot show the membranous labyrinth itself. On MR images it is not the vestibular aqueduct that is visualized but its contents, the endolymphatic duct and sac, and can show the abnormalities of the fluid spaces related to the membranous labyrinth. It is proposed that recurrent benign paroxysmal positional vertigo (BPPV) is related with volumetric abnormalities of vestibular aqueduct. This verifiable hypothesis tries to define this rapport and explore new diagnostic and therapeutic possibilities.

Vertigo and vigorous horizontal spontaneous nystagmus in a presenting patient is usually taken to indicate unilaterally reduced horizontal canal function. However here we report results which question that presumption. In three such patients with an acute vestibular syndrome, complete testing of all peripheral vestibular sense organs using new tests of canal and otolith function (vHIT and VEMPs) showed that semicircular canal function was normal, but that there were unilateral otolithic deficits which probably caused their acute syndrome.

The n10 component of the ocular vestibular evoked myogenic potential (oVEMP) to sound and vibration stimuli is a crossed response that has enhanced amplitude and decreased threshold in patients with CT-verified superior semicircular canal dehiscence (SSCD). However, demonstrating enhanced VEMP amplitude and reduced VEMP thresholds requires multiple trials and can be very time consuming and tiring for patients, so a specific indicator of probable SCD that is fast and not tiring would be preferred. Here we report a 1-trial indicator: that the oVEMP n10 in response to a very high frequency stimulus (4000 Hz), either air-conducted sound (ACS) or bone conducted vibration (BCV), is such a fast indicator of probable SCD. In 22 healthy subjects, oVEMP n10 at 4000 Hz was not detectable; however, in all 22 CT-verified SSCD patients tested, oVEMP n10 responses were clearly present to 4000 Hz to either ACS or BCV stimuli.

The presence of spontaneous nystagmus in darkness with a strong horizontal component has been taken to indicate that there is asymmetrical function of the horizontal semicircular canals. If this horizontal spontaneous nystagmus can be suppressed by vision, then it is regarded as due to peripheral horizontal canal dysfunction. However, we report evidence from one patient (61-year-old male), who visited the MSA ENT Clinic, Cassino (FR) Italy, reporting acute, severe vertigo, postural unsteadiness, nausea and vomiting associated with right sudden hearing loss. The patient received instrumental audiovestibular testing to obtain objective measurements of his inner-ear receptors. At the time of the attack, the patient showed spontaneous nystagmus, mainly with horizontal and vertical components (3D infrared video-oculography). Video head-impulse tests of dynamic horizontal canal function showed that the functional status of both horizontal canals was within the normal range. Cervical VEMPs to 500 Hz bone-conducted vibration at Fz showed normal results; ocular VEMPs to the same stimulus showed a reduced n10 amplitude beneath the left eye, corresponding to the right ear. For this reason, the patient was diagnosed as having right unilateral selective utricular macula lesion due to labyrinthitis. There is considerable evidence of convergence of neural input from the otoliths onto horizontal canal neurons in the vestibular nuclei. The firing of such neurons could reflect either asymmetrical horizontal canal function or asymmetrical utricular function. The problem with this patient was not due to asymmetrical horizontal canal function, but only to asymmetrical utricular function, demonstrated by the results of the oVEMP test.

Objective: To explore vestibular integrity by bone vibration-induced nystagmus (VIN) during bedside examination. Disease or dysfunction of vestibular end organs would reduce or eliminate their contribution to total eye movement response to VIN. Background: It is assumed that vibration of the mastoid (at a frequency of 100 Hz) stimulates all vestibular end organs (semicircular canals and otolith structures). Previous studies have described oculomotor responses to vestibular activation by vibratory stimulus. Stimulation of individual semicircular canals produces eye movement in the plane of the stimulated canal. Vibratory stimulation of otolith structures (utricular macula) produces changes in ocular torsional position. Superior semicircular canal dehiscence (SCD) is responsible for nontypical cochleovestibular symptoms. Diagnosis is difficult without resorting to imaging, high-resolution computed tomography (HRCT) being the only tool providing reliable assessment. To avoid unnecessary referral for expensive imaging, it would be useful to have a simple screening test to select cases for HRCT. Methods: Video eye movements were recorded in complete darkness in patients diagnosed with SCD. The eye movement responses to long-lasting unilateral vibratory stimulation applied to the mastoid surface were evaluated. Results: VIN evoked a response in all cases, mostly demonstrating excitation of the affected side. The pattern of vertical, torsional and horizontal eye velocity and eye position was evaluated with three-dimensional infrared video-oculography (50 Hz sampling). Conclusion: Analysis of VIN, recently proposed to study transmission of excitatory stimuli by bone conduction, may be appropriate for altered immittance caused by dehiscence. This promises to be an interesting new field of research.

Welgampola and Carey have missed evidence that shows how utricular and saccular function can be differentiated, and here the authors note that evidence and report a new result that further substantiates the differentiation.

‘‘For both BCV and ACS, the p13-n23 components of the cVEMPs recorded from the left SCM were greatly reduced or absent, but the p13-n23 recorded from the right SCM was present (Figs. 1, 2). For this reason, and given the other normal vestibular and audiological test results, the patient was diagnosed as having left inferior vestibular neuritis [5–7]. For both BCV and ACS, the oVEMP n10 recorded beneath both eyes is clearly present and approximately symmetrical (i.e. normal).’’