OBJECTIVE: To establish a case series where loss of magnetic resonance fluid signal intensity in the posterior semicircular canal (SCC) corresponded with a functional deficit on clinical and video head impulse testing, and most likely a result of canal fibrosis or obstruction.
METHODS: Three patients with an magnetic resonance imaging (MRI) showing loss of T2-weighted signal intensity in their posterior SCC corresponding to a vestibular weakness in that canal.
METHODS: All patients underwent a comprehensive neuro-otologic examination. Vestibulo-ocular reflex was evaluated using clinical head impulse testing (cHIT) and quantified with video head impulse testing. MRI for all patients was obtained using clinical protocols for gadolinium-enhanced MRI of the internal auditory canal on 1.5 or 3 T scanners, which all included high-resolution, heavily T2-weighted imaging of the membranous labyrinth.
METHODS: Correlation of MRI findings with vestibular weakness in the corresponding posterior SCC.
RESULTS: Subject 1 showed abnormal vHIT in the left lateral and left posterior SCCs. MRI showed loss of T2 signal intensity of the entire left posterior SCC as well as in the posterior limb of the superior SCC. Subject 2 showed isolated loss of function (cHIT) and low gain with catch-up saccade (vHIT) of the left posterior SCC. MRI showed loss of T2 signal intensity of the superior portion of the left posterior SCC, as well as in the posterior limb of the superior SCC. Subject 3 showed catch-up saccades of the left posterior SCC on cHIT and vHIT and loss of T2 signal intensity of the entire left posterior SCC and partial loss of bilateral lateral SCC on MRI.
CONCLUSIONS: In this case series, loss of posterior SCC function correlated with vestibular function testing and high-resolution, T2-weighted MRI findings, perhaps related to fibrosis of the posterior SCC.

Current clinical practice considers the vestibulo-ocular reflex (VOR) gain as registered by the video head impulse test (vHIT) as the primary measure for semicircular canal function, while the role of the re-fixation saccades (RSs) is still under evaluation. The goal of the study was to appraise the added benefit of RS towards the improvement of vHIT diagnostic accuracy in cases of suspected left horizontal semicircular canal dysfunction.
The vHIT recordings of 40 patients with left-sided horizontal VOR gains <0.8 were retrospectively evaluated for the presence of RS. The study groups included 20 patients with a final diagnosis of left horizontal semicircular canal dysfunction and 20 patients for whom vestibular dysfunction was ruled out.
Gain values >0.72 were found in all patients with no vestibular disease and in 4 (20%) patients having vestibulopathy. Significantly higher average left-sided RS velocity and frequency were found among the vestibular patients. VOR gain <0.72 was found to be highly specific for the diagnosis of vestibular dysfunction. However, for gain values in the range of 0.72-0.79, the presence of RS with frequency >80% largely improved vHIT diagnostic accuracy.
Although VOR gain <0.8 is considered to reflect dysfunction, a significant false-positive rate for left-sided horizontal vHIT was found for gains in the range of 0.72-0.79. The presence of RS with frequency >80% could improve vHIT diagnostic ability in these patients.

Lateral semicircular canal (LSCC) malformations represent one of the most common types of inner ear malformation. As many cases of LSCC malformations are asymptomatic, detailed vestibular functions in such cases remain unclear. We present a case with bilateral LSCC malformations for whom the function of each vestibular organ was evaluated by caloric testing, video Head Impulse Test (vHIT) and vestibular evoked myogenic potentials (VEMP). Caloric testing showed canal paresis of the left side, whereas vHIT showed bilateral normal semicircular canal function. The results of VEMP indicated left saccular dysfunction. Discrepancies in caloric testing and vHIT results were observed and these discrepancies are thought to be due to endolymphatic hydrops rather than vestibular hypofunction, similar to that in Meniere disease.

We describe herein the case of a patient whose primary complaints were episodic vertigo and \"depersonalization,\" a sensation of detachment from his own body.
This case study aims to further clinical knowledge and insight into the clinical evaluation of vertiginous patients with complaints of depersonalization.
This is a case study.
A retrospective chart review of vestibular function testing done on a vertiginous patient with complaints of depersonalization was performed.
Vestibular function testing revealed absent cervical and ocular vestibular evoked myogenic potentials on the left side with normal vHIT or video Head Impulse Test, videonystagmography, and rotational chair results, suggesting peripheral vestibular impairment isolated to the left saccule and utricle.
The otolith end organ impairment explains the patient\'s postural deviation to the left side during attempts to ambulate. We recommend that clinicians should be attentive to patient complaints of depersonalization and perform vestibular evoked myogenic potential testing to determine whether evidence of at least a unilateral peripheral otolith end organ impairment exists.

OBJECTIVE: To explore the usefulness of the responses of video head impulse testing (vHIT) in assessing symptomatic patients with superior semicircular canal dehiscence (SSCD).
METHODS: This was a prospective case-control study performed in a tertiary skull base referral Centre in the UK. It included all patients ¬diagnosed with SSCD from January 2015 to January 2019 and compared to a control group of age and gender-matched unaffected indi¬viduals. The main outcome of the study was semicircular canal vestibule-ocular reflex (VOR) gains during vHIT assessment and link to patients\' symptoms.
RESULTS: A total of 28 patients were diagnosed with SSCD during the study period and completed the vHIT assessment. Reduced VOR gains (<0.8) were noted in 57% of patients (n = 16). Half of these (n = 8) were in canals other than the superior semicircular (posterior only: n = 5; lateral and posterior: n = 3). Three patients (10.7%) had abnormal responses in 2 canals. The canals in the contralateral side were affected in 56.5% of the cases. There was no correlation with the patients\' symptoms. Results were directly comparable with the control group vHIT results with no identifiable statistically significant differences on comparison of the ipsilateral SSCD side with a randomly selected side from the control group (all comparisons: P > .05).
CONCLUSIONS: SSCD can affect the vestibular responses from all 3 semicircular canals; not necessarily the superior one. Similar responses were found in a control group of normal subjects. Although the use of vHIT in the assessment of SSCD is not diagnosis-specific, it can still help with identifying the impact of surgery on all canals prior to any intervention in order to avoid bilateral vestibular failure.

OBJECTIVE: Acute vestibular syndrome (AVS) is a common cause of emergency admittance and has very rarely been reported due to a vestibular nucleus infarction. Initial magnetic resonance imaging studies (MRIs) including diffusion-weighted images may reveal normal results and even bedside examination tests like HINTS battery which involves head impulse test (HIT), nystagmus and test of skew can be challenging in differing a peripheral vestibulopathy from a central lesion.
METHODS: Four patients seen in the emergency department with AVS and evaluated with HINTS battery, cervical vestibular-evoked myogenic potentials (cVEMP) and cranial MRI revealing infarcts restricted to vestibular nuclei were evaluated.
RESULTS: In two patients spontaneous nystagmus beating towards the unaffected side was present. In one patient spontaneous nystagmus changed direction on looking to the affected side. In the fourth gaze evoked nystagmus was present without any spontaneous nystagmus. In all, HIT was positive to the affected side. In three cVEMPs was studied revealing delayed latency, reduced amplitude p13/n23 potentials on the lesioned side in two of them. Initial MRIs including diffusion-weighted images disclosed acute infarction in the area of the vestibular nuclei in two patients, with normal results in the other two. Follow-up MRI\'s performed 48 hours later revealed vestibular nuclear infarction.
CONCLUSIONS: It is not always easy to differentiate small lesions restricted to central vestibular structures from peripheral vestibular lesions both on clinical and radiological grounds. Follow-up cranial MRI is necessary in patients with known vascular risk factors.

OBJECTIVE: The aim of the study was to evaluate the auditory and motor functions in children with insulin dependent diabetes mellitus (IDDM).
METHODS: This case-control study, 65 diabetic children, receiving care in Diabetes Center of 17 Sharivar Hospital, were enrolled. 130 controls were matched to cases by age and sex. The authors performed audio-vestibular tests, including pure tone audiometry (PTA), distortion product otoacoustic emission (DPOAE), auditory brainstem response (ABR), bedside head-impulse test and dynamic visual acuity test. Motor function was evaluated using of Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2).
RESULTS: The results showed higher thresholds of air conduction PTA and a prolonged peak latency of wave V (ABR) in diabetic children as compared to controls (all Ps < 0.001). The odds of normal response in DPOAE of cases decreased by 0.44-0.82 - fold. Although clinical vestibular outcomes were worse in cases, differences were not significant. In BOT-2, the cases had statistically significant lower scores (standard score = -0.58, P < 0.05) than the controls for the Total Motor Composite. Also diabetic girls had more skill motor impairment compared to boys with IDDM.
CONCLUSIONS: Based on our study, metabolic disturbances present in Type I diabetes cause disturbances in different parts of auditory and balance functions.

The current paper reports on a patient with recurrent rotational vertigo and persistent dizziness and imbalance lasting several weeks, who underwent extensive neuro-otological and radiological examinations. Pathological findings initially included right-sided benign paroxysmal positional vertigo (BPPV), persistent horizontal spontaneous nystagmus (SPN) to the left, and a pathological bedside and video head impulse test (HIT) on the left. The pathological HIT on the left and the SPN to the left indicated a central origin. Therefore, cranial magnetic resonance imaging was performed which revealed a left-sided ischemic stroke in the territory of the medial branch of the posterior inferior cerebellar artery (mPICA).

The current paper reports on a patient with recurrent rotational vertigo and persistent dizziness and imbalance lasting weeks, who underwent extensive neurootological and radiological examination. Pathological findings initially included right-sided benign paroxysmal positional vertigo (BPPV), persistent horizontal spontaneous nystagmus (SPN) to the left and a pathological bedside and video head impulse test (HIT) on the left. The pathological HIT on the left and SPN to the left indicated a central genesis. Therefore, cMRI was performed and revealed a left-sided cerebral infarction in the territory of the medial branch of the posterior inferior cerebellar artery (mPICA).

Introduction A patient who had no symptoms suggestive of bilateral loss of vestibular function presented no responses in rotational and caloric tests. Objectives To demonstrate the importance of the video head impulse test in neuro-otologic diagnosis. Resumed Report This patient had a neuro-otologic evaluation and presented no responses in torsion swing tests, caloric tests, and rotational tests in a Bárány chair. The video head impulse test elicited responses in four of the six semicircular canals. Conclusion Absent responses in caloric and rotatory tests alone are not sufficient to diagnose bilateral loss of vestibular function.