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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...

In 2017, the Committee for Classification of Vestibular Disorders of the Barany Society unified four dizziness disorders under the definition of persistent postural perceptual dizziness (PPPD). Currently, the efficacy of vestibular training (VR) in treating patients with PPPD is still under debate. The aim of this scoping review is to evaluate the possible clinical application of VR alone or in combination with other therapy in patients with PPPD. Electronic databases searched in May 2021 were PubMed/MEDLINE, Cochrane Library and Physiotherapy Evidence Database and the data selection was conducted in accordance with the PRISMA-ScR extension for scoping reviews. Electronic searches identified 41 studies and after the selection process 7 studies met the inclusion criteria and were included. We reported a narrative summary of results and presented the overall clinical parameters and outcomes of all included studies in a tabular format. An accurate instrumental assessment of the vestibular function is needed to guide the clinical reasoning in the management of patients with PPPD. Considering the lack of RCTs, a consensus is needed to develop a shared and robust framework to find the best rehabilitative treatment for individuals with PPPD.

As previously reported, a single test measuring oVEMP n10 to 4000 Hz stimuli (bone-conducted vibration (BCV) or air-conducted sound (ACS)) provides a definitive diagnosis of semicircular canal dehiscence (SCD) in 22 CT-verified patients, with a sensitivity of 1.0 and specificity of 1.0. This single short screening test has great advantages of speed, minimizing testing time, and the exposure of patients to stimulation. However, a few studies of the 4000 Hz test for SCD have reported sensitivity and specificity values which are slightly less than reported previously. We hypothesized that the rise time of the stimulus is important for detecting the oVEMP n10 to 4000 Hz, similarly to what we had shown for 500 and 750 Hz BCV. We measured oVEMP n10 in 15 patients with CT-verified SCD in response to 4000 Hz ACS or BCV stimuli with rise times of 0, 1, and 2 ms. As a result, increasing the rise time of the stimulus reduced the oVEMP n10 amplitude. This outcome is expected from the physiological evidence of guinea pig primary vestibular afferents, which are activated by sound or vibration. Therefore, for clinical VEMP testing, short rise times are optimal (preferably 0 ms).

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.

We have previously reported that a single test measuring oVEMP n10 to 4000Hz stimuli (either bone-conducted vibration (BCV) or air-conducted sound (ACS)) provides a definitive diagnosis of semicircular canal dehiscence (SCD) in 22 CT-verified patients with a sensitivity of 1.0 and specificity of 1.0. Such a single short screening test has great advantages of speed, minimizing testing time and the exposure of patients to stimulation. However some studies of the 4000Hz test for SCD have reported sensitivity and sensitivity values somewhat less that what we reported.

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.

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.

Superior Canal Dehiscence is classically diagnosed with typical abnormalities on Vestibular Evoked Myogenic Potentials (VEMPs) and Computed Tomography (CT) scans.This paper discusses the utility of the video Head Impulse Test (vHIT) in SCD.Data from 11 ears (8 patients) with SCD were retrospectively reviewed. Results from vHIT, VEMPs and CT and when possible, MRI scans were correlated. An audit of 300 vHIT from patients undergoing routine testing for any neurotological complaint was also conducted to look at the incidence of isolated abnormal superior canal function.82% of patients (9 ears) with SCD showed abnormal vHIT (reduced gain and catch-up saccades) isolated to the affected superior semicircular canal.Correlation of the CT and VEMPs are important in forming a diagnosis of SCD. However, if isolated superior canal vHIT abnormalities are demonstrated, it is suggestive of SCD and such patients should be referred for further investigations.

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

BACKGROUND Balance disorders are present in patients with Multiple Sclerosis and part of these disorders could be of vestibular origin. Vestibular Rehabilitation was found to be effective in improving balance in patients with central vestibular dysfunction. OBJECTIVE To investigate the clinical effects of vestibular rehabilitation on balance skills and secondly on fatigue and activity of daily living in highly disabled multiple sclerosis people. METHODS Thirty hospitalized participants with severe multiple sclerosis (EDSS 6-7) were randomly assigned to the experimental group (15 patients -9F-; mean age 50.64±11.73) and the control group (15 patients -8F-; mean age 45.77±10.91). All patients were evaluated before and after treatment with the Expanded Disability Status Scale, Barthel Index Tinetti Balance and Gait scale, Berg Balance Scale, Fatigue Severity Scale, Two Minute Walking Test and Timed 25-foot walk test. Two follow-ups (i.e., at 30 and 60 days after treatment) were carried out with Barthel Index. RESULTS Significant improvement was found in the experimental group with respect to the control group (p < 0,05) in balance, fatigue perception, activities of daily living and short distance gait. No significant improvements were found for gait endurance as measured by Two Minute Walking Test. CONCLUSIONS Four weeks of Vestibular Rehabilitation training results in less fatigue, improved balance and performance of the activities of daily living in patients with severe Multiple Sclerosis.

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.

Vestibular neuritis (VN) is one of the most common causes of acute vestibular syndrome (AVS). Quantifying the vestibulo-ocular reflex (VOR) gain by the video Head Impulse Test (vHIT) could provide useful information to diagnose VN. This study aims to retrospectively evaluate the VOR gain values during the acute and subacute stages of the VN and to correlate these values with the patients’ dizziness-related handicap. Medical record of 28 patients with VN were reviewed. Patients were assigned to two groups according to the time since the acute vestibular syndrome (AVS). One group with patients assessed within seventy-two hours since the AVS (AVSg) and one group with patients evaluated from four days to six weeks since the AVS (PAVSg). VOR gain was evaluated in all selected patients and correlated to Dizziness Handicap Inventory (DHI). Significant differences were found in the between-subjects analysis in DHI score (p= 0.000) and in the ipsilesional hVOR gain values (p= 0.001). The correlation analysis showed significant results (p= 0.017) between DHI score (40 ± 16.08) and ipsilesional VOR gain (0.54 ± 0.09) in the PAVSg. Patients evaluated within 72 h since the AVS showed anticompensatory saccades (AcS) turning the head toward the contralesional side. Patients with unilateral Superior VN (SVN) could have dissimilar hVOR gain values and DHI score according to the damage of the VIII pair of cranial nerves. AcS in the contralesional side is a sign of acute phase in patients with unilateral SVN.&nbsp

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.

Background: The aim of this study was to identify the prevalence of tinnitus in a sample of people with early stages of Meniere’s disease. Material and methods: A postal survey was sent to 256 patients all judged to fulfil the criteria of early unilateral Meniere’s disease established by the American Academy of Otolaryngology Committee on Hearing and Equilibrium. Of these 256 patients, 136 had probable Meniere’s disease and 120 had early possible Meniere’s disease. The same questionnaire was mailed and administered to 60 control subjects with no history of vestibular dysfunction. A total of 158 subjects completed the questionnaire. Results: Tinnitus was found in 54 (63%) of the 72 members of the final unilateral vestibular Meniere’s disease group and 61 (85 %) of the 72 members of the final unilateral probable Meniere’s disease group. Conclusion: The prevalence of tinnitus as determined by a questionnaire survey was significantly greater in patients with probable Meniere’s disease than in patients with early vestibular Meniere’s disease or in control subjects. However, the prevalence of tinnitus as determined by a questionnaire survey was significantly greater in patients with early vestibular Meniere’s disease than in control subjects.

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.

Through selective tests of the function of the canal and otolith sense organs, it is possible to assert that patient conditions are purely otolithic and that the canals are not involved. The video head impulse test selectively tests each semicircular canal; the ocular vestibular-evoked myogenic potential to 500 Hz Fz (Fz is the location on the forehead in the midline at the hairline) bone-conducted vibration (BCV) selectively tests the utricular macula and the cervical vestibular-evoked myogenic potential to 500 Hz Fz BCV selectively tests the saccular macula. The development of new specific tests of otolith function has shown that some patients may have specific deficits of just otolithic function. In the authors' experience, patients who complain strongly of postural unsteadiness should be suspected to have otolithic deficits. They may also have vertigo and in some cases have spontaneous nystagmus of peripheral origin, even though their semicircular canal function is normal. The prognosis for such patients is good. They usually appear to regain their postural stability spontaneously over weeks (or longer), even though they still have an otolithic deficit as shown by objective tests when they are free of symptoms. It is not known what procedures may accelerate the recovery of otolith function.

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.

OBJECTIVE The aim of this study was to investigate the effect of superior semicircular canal dehiscence (SSCD) on the n10 component of the ocular vestibular evoked myogenic potential (oVEMP n10) and the p13-n23 component of the cervical vestibular evoked myogenic potential (cVEMP p13-n23) evoked by 500 Hz bone-conducted vibration (BCV) at the midline forehead at the hairline (Fz) in 26 patients with computed tomography-verified SSCD. Previous evidence has led to the proposal that the oVEMP n10 is of utricular origin whereas the cVEMP p13-n23 is of saccular origin. The question is can the oVEMP n10 to 500 Hz BCV indicate SSCD? DESIGN A hand-held Bruel & Kjaer 4810 Minishaker was used to provide BCV stimulation using surface electromyography electrodes to record oVEMP n10 and cVEMP p13-n23. The stimulus was 7 msec bursts of 500 Hz BCV at either Fz or at the vertex of the skull (Cz). Twenty-seven healthy subjects were tested in the same paradigm. RESULTS In response to 500 Hz Fz BCV in SSCD patients the oVEMP n10 amplitude beneath the contraSSCD eye was substantially and significantly larger than the oVEMP n10 beneath the ipsiSSCD eye, whereas in these same patients the cVEMP p13-n23 amplitude over the ipsiSSCD sternocleidomastoid muscle to Fz BCV was slightly but significantly larger than the cVEMP p13-n23 amplitude over the contraSSCD sternocleidomastoid muscle. In SSCD patients there was a significant relationship between the size of the dehiscence and the amplitude of the contralateral oVEMP n10 potential. The oVEMP n10 to Cz stimulation was still present in SSCD patients, but small or absent in healthy subjects. CONCLUSIONS In response to 500 Hz Fz BCV an asymmetrical oVEMP n10 with a significantly increased amplitude of contralesional oVEMP n10 (compared with population values of healthy subjects) is a simple useful indicator of SSCD, confirmed by the Cz response. oVEMP testing with 500 Hz Fz BCV allows very simple, very fast identification of a probable unilateral SSCD.

Background and aims:Previous evidence shows that the n10 component of the ocular vestibular evoked myogenic potential indicates utricular function, while the p13 component of the cervical vestibular evoked myogenic potential indicates saccular function. This study aimed to assess the possibility of differential utricular and saccular function testing in the clinic, and whether loss of saccular function affects utricular response.Methods:Following vibration conduction from the mid-forehead at the hairline, the ocular n10 component was recorded by surface electromyograph electrodes beneath both eyes, while the cervical p13–n23 component was recorded by surface electrodes over the tensed sternocleidomastoid muscles.Results:Fifty-nine patients were diagnosed with probable inferior vestibular neuritis, as their cervical p13–n23 component was asymmetrical (i.e. reduced or absent on the ipsilesional side), while their ocular n10 component was symmetrical (i.e. normal beneath the contralesional eye).Conclusion:The sense organ responsible for the cervical and the ocular vestibular evoked myogenic potentials cannot be the same, as one response was normal while the other was not. Reduced or absent saccular function has no detectable effect on the ocular n10 component. On vibration stimulation, the ocular n10 component indicates utricular function and the cervical p13–n23 component indicates saccular function.

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.