Characteristics of spontaneous nystagmus and its correlation to video head impulse test findings in vestibular neuritis.
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ABSTRACT:
SUBMITTER: Zhang X
PROVIDER: S-EPMC10477358 | biostudies-literature | 2023
REPOSITORIES: biostudies-literature
Publications
Characteristics of spontaneous nystagmus and its correlation to video head impulse test findings in vestibular neuritis.
Zhang Xueqing X Deng Qiaomei Q Liu Yao Y Li Shanshan S Wen Chao C Liu Qiang Q Huang Xiaobang X Wang Wei W Chen Taisheng T
Frontiers in neuroscience 20230822
<h4>Objective</h4>To explore the direction and SPV (slow phase velocity) of the components of spontaneous nystagmus (SN) in patients with vestibular neuritis (VN) and the correlation between SN components and affected semicircular canals (SCCs). Additionally, we aimed to elucidate the role of directional features of peripheral SN in diagnosing acute vestibular syndrome.<h4>Materials and methods</h4>A retrospective analysis was conducted on 38 patients diagnosed with VN in our hospital between 20 ...[more]
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Project description:Vestibular rehabilitation of patients in whom the level of vestibular function is continuously changing requires different strategies than in those where vestibular function rapidly becomes stable: where it recovers or where it does not and compensation is by catch-up saccades. In order to determine which of these situations apply to a particular patient, it is necessary to monitor the vestibulo-ocular reflex (VOR) gains, rather than just make a single measurement at a given time. The video Head Impulse Test (vHIT) is a simple and practical way to monitor precisely the time course and final level of VOR recovery and is useful when a patient has ongoing vestibular symptoms, such as after acute vestibular neuritis. In this study, we try to show the value of ongoing monitoring of vestibular function in a patient recovering from vestibular neuritis. Acute vestibular neuritis can impair function of any single semicircular canal (SCC). The level of impairment of each SCC, initially anywhere between 0 and 100%, can be accurately measured by the vHIT. In superior vestibular neuritis the anterior and lateral SCCs are the most affected. Unlike after surgical unilateral vestibular deafferentation, SCC function as measured by the VOR can recover spontaneously after acute vestibular neuritis. Here we report monitoring the VOR from all 6 SCCs for 500 days after the second attack in a patient with bilateral sequential vestibular neuritis. Spontaneous recovery of the VOR in response to anterior and lateral SCC impulses showed an exponential recovery with a time to reach stable levels being longer than previously considered or reported. VOR gain in response to low-velocity lateral SCC impulses recovered with a time constant of around 100 days and reached a stable level at about 200 days. However, in response to high-velocity lateral SCC and anterior SCC impulses, VOR gain recovered with a time constant of about 150 days and only reached a stable level toward the end of the 500 days monitoring period.
| S-EPMC7399092 | biostudies-literature
Project description:BackgroundAcute vestibular syndrome usually represents either vestibular neuritis (VN), an innocuous viral illness, or posterior circulation stroke (PCS), a potentially life-threatening event. The video head impulse test (VHIT) is a quantitative measure of the vestibulo-ocular reflex that can distinguish between these two diagnoses. It can be rapidly performed at the bedside by any trained healthcare professional but requires interpretation by an expert clinician. We developed machine learning models to differentiate between PCS and VN using only the VHIT.MethodsWe trained machine learning classification models using unedited head- and eye-velocity data from acute VHIT performed in an Emergency Room on patients presenting with acute vestibular syndrome and whose final diagnosis was VN or PCS. The models were validated using an independent test dataset collected at a second institution. We compared the performance of the models against expert clinicians as well as a widely used VHIT metric: the gain cutoff value.ResultsThe training and test datasets comprised 252 and 49 patients, respectively. In the test dataset, the best machine learning model identified VN with 87.8% (95% CI 77.6%-95.9%) accuracy. Model performance was not significantly different (p = 0.56) from that of blinded expert clinicians who achieved 85.7% accuracy (75.5%-93.9%) and was superior (p = 0.01) to that of the optimal gain cutoff value (75.5% accuracy (63.8%-85.7%)).ConclusionMachine learning models can effectively differentiate PCS from VN using only VHIT data, with comparable accuracy to expert clinicians. They hold promise as a tool to assist Emergency Room clinicians evaluating patients with acute vestibular syndrome.
| S-EPMC11882619 | biostudies-literature
Project description:We describe a rare case of spontaneous upbeat nystagmus (UBN) attributable to a canalith jam involving the anterior semicircular canal (ASC) in a patient in whom comprehensive vestibular assessment was useful to identify the underlying pathomechanism. A 56-year-old woman with unsteadiness following repositioning procedures for left-sided benign paroxysmal positional vertigo (BPPV) presented with spontaneous UBN that showed slight right torsional components. A vestibular test battery detected isolated left ASC hypofunction on a video-head impulse test (Video-HIT). We postulated a persistent utriculopetal deflection of the left ASC cupula, which was attributable to entrapment of debris in a narrow canal tract, with consequent sustained inhibition of the ampullary afferents. Although spontaneous UBN receded after impulsive physical therapy, unsteadiness deteriorated into positional vertigo secondary to canalolithiasis involving the ipsilateral posterior canal. In our view, physical therapy possibly fragmented the canalith jam and released free-floating otoconia that eventually settled into the ipsilateral posterior canal. Video HIT revealed normalization of ASC hypofunction, and leftsided posterior canal canalolithiasis was successfully treated using appropriate repositioning procedures. We propose that a canalith jam involving the ASC should be considered in the differential diagnosis of spontaneous UBN, particularly in patients with a history of BPPV and isolated ASC hypofunction detected on video HIT.
| S-EPMC9271735 | biostudies-literature
Project description:ObjectiveWhile 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.MethodsHIMP 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.ResultsVestibulo-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, p < 0.001). 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.ConclusionsWhile 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.Classification of evidenceThis case-control study provides Class III evidence that SHIMP accurately identifies patients with unilateral or bilateral vestibulopathies.
| S-EPMC4977115 | biostudies-literature
Project description: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.
| S-EPMC4687993 | biostudies-other
Project description:ObjectiveWe sought to quantify and compare angular vestibulo-ocular reflex (aVOR) gain and compensatory saccade properties elicited by the head impulse test (HIT) in pontine-cerebellar stroke (PCS) and vestibular neuritis (VN).MethodsHorizontal HIT was recorded ≤7 days from vertigo onset with dual-search coils in 33 PCS involving the anterior inferior, posterior inferior, and superior cerebellar arteries (13 AICA, 17 PICA, 3 SCA) confirmed by MRI and 20 VN. We determined the aVOR gain and asymmetry, and compensatory overt saccade properties including amplitude asymmetry and cumulative amplitude (ipsilesional trials [I]; contralesional trials [C]).ResultsThe aVOR gain (normal: 0.96; asymmetry = 2%) was bilaterally reduced, greater in AICA (I = 0.39, C = 0.57; asymmetry = 20%) than in PICA/SCA strokes (I = 0.75, C = 0.74; asymmetry = 7%), in contrast to the unilateral deficit in VN (I = 0.22, C = 0.76; asymmetry = 54%). Cumulative amplitude (normal: 1.1°) was smaller in AICA (I = 4.2°, C = 3.0°) and PICA/SCA strokes (I = 2.1°, C = 3.0°) compared with VN (I = 8.5°, C = 1.3°). Amplitude asymmetry in AICA and PICA/SCA strokes was comparable, but favored the contralesional side in PICA/SCA strokes and the ipsilesional side in VN. Saccade asymmetry <61% was found in 97% of PCS and none of VN. Gain asymmetry <40% was found in 94% of PCS and 10% of VN.ConclusionHIT gains and compensatory saccades differ between PCS and VN. VN was characterized by unilateral gain deficits with asymmetric large saccades, AICA stroke by more symmetric bilateral gain reduction with smaller saccades, and PICA stroke by contralesional gain bias with the smallest saccades. Saccade and gain asymmetry should be investigated further in future diagnostic accuracy studies.Classification of evidenceThis study provides Class II evidence that aVOR testing accurately distinguishes patients with PCS from VN (sensitivity 94%-97%, specificity 90%-100%).
| S-EPMC4222852 | biostudies-literature
Project description:We describe a case series of labyrinthine fistula, characterized by Hennebert's sign (HS) elicited by tragal compression despite global hypofunction of semicircular canals (SCs) on a video-head impulse test (vHIT), and review the relevant literature. All three patients presented with different amounts of cochleo-vestibular loss, consistent with labyrinthitis likely induced by labyrinthine fistula due to different temporal bone pathologies (squamous cell carcinoma involving the external auditory canal in one case and middle ear cholesteatoma in two cases). Despite global hypofunction on vHIT proving impaired function for each SC for high accelerations, all patients developed pressure-induced nystagmus, presumably through spared and/or recovered activity for low-velocity canal afferents. In particular, two patients with isolated horizontal SC fistula developed HS with ipsilesional horizontal nystagmus due to resulting excitatory ampullopetal endolymphatic flows within horizontal canals. Conversely, the last patient with bony erosion involving all SCs developed mainly torsional nystagmus directed contralaterally due to additional inhibitory ampullopetal flows within vertical canals. Moreover, despite impaired measurements on vHIT, we found simultaneous direction-changing positional nystagmus likely due to a buoyancy mechanism within the affected horizontal canal in a case and benign paroxysmal positional vertigo involving the dehiscent posterior canal in another case. Based on our findings, we might suggest a functional dissociation between high (impaired) and low (spared/recovered) accelerations for SCs. Therefore, it could be hypothesized that HS in labyrinthine fistula might be due to the activation of regular ampullary fibers encoding low-velocity inputs, as pressure-induced nystagmus is perfectly aligned with the planes of dehiscent SCs in accordance with Ewald's laws, despite global vestibular impairment on vHIT. Moreover, we showed how pressure-induced nystagmus could present in a rare case of labyrinthine fistulas involving all canals simultaneously. Nevertheless, definite conclusions on the genesis of pressure-induced nystagmus in our patients are prevented due to the lack of objective measurements of both low-acceleration canal responses and otolith function.
| S-EPMC8039292 | biostudies-literature
Project description:Background and objectiveMigraine is an extremely prevalent primary headache disorder that frequently associates parallel symptoms such as dizziness, tinnitus and hearing loss. Our aim is to investigate differences in video head impulse (vHIT) results with patients suffering from vestibular migraine (VM) and healthy people, taking into consideration mean values of vestibule ocular reflex (VOR) gain, occurrence of the compensatory saccades latency and amplitude. According to the results, determine the usefulness of vHIT in vestibular migraine diagnostics.MethodsA total number of 120 subjects were enrolled in the study, 80 of them were vestibular migraine patients (VM), while the other 40 were a control group of age matched healthy subjects. History was taking during the evaluation; videonystagmography and the video head impulse test were done.ResultsThe rate of saccades is much more higher in the VM group compared to the healthy subjects group, only 7.5% of the VM group showed a low VOR gain with compensatory saccades denoting a vestibular deficit.ConclusionThe refixation saccades are an important sign that could underlie different vestibular problems. vHIT result can contribute to the completion of full mosaic of vestibular migraine diagnostics.
| S-EPMC6291630 | biostudies-literature
Project description:ObjectiveTo determine the accuracy of the bedside head impulse test (bHIT) by direct comparison with results from the quantitative head impulse test (qHIT) in the same subjects, and to investigate whether bHIT sensitivity and specificity changes with neuro-otological training.MethodsVideo clips of horizontal bHIT to both sides were produced in patients with unilateral and bilateral peripheral vestibular deficits (n = 15) and in healthy subjects (n = 9). For qHIT, eye and head movements were recorded with scleral search coils on the right eye and the forehead. Clinicians (neurologists or otolaryngologists) with at least 6 months of neuro-otological training ("experts": n = 12) or without this training ("non-experts": n = 45) assessed video clips for ocular motor signs of vestibular deficits on either side or of normal vestibular function.ResultsOn average, bHIT sensitivity was significantly (t test: p<0.05) lower for experts than for non-experts (63% vs 72%), while bHIT specificity was significantly higher for experts than non-experts (78% vs 64%). This outcome was a consequence of the experts' tendency to accept bHIT with corresponding borderline qHIT values as still being normal. Fitted curves revealed that at the lower normal limit of qHIT, 20% of bHIT were rated as deficient by the experts and 37% by the non-experts.ConclusionsWhen qHIT is used as a reference, bHIT sensitivity is adequate and therefore clinically useful in the hands of both neuro-otological experts and non-experts. We advise performing quantitative head impulse testing with search coils or high speed video methods when bHIT is not conclusive.
| S-EPMC2117540 | biostudies-literature
Project description:BackgroundThe head impulse test (HIT) is a useful bedside test to identify peripheral vestibular deficits. However, such a deficit of the vestibulo-ocular reflex (VOR) may not be diagnosed because corrective saccades cannot always be detected by simple observation. The scleral search coil technique is the gold standard for HIT measurements, but it is not practical for routine testing or for acute patients, because they are required to wear an uncomfortable contact lens.ObjectiveTo develop an easy-to-use video HIT system (vHIT) as a clinical tool for identifying peripheral vestibular deficits. To validate the diagnostic accuracy of vHIT by simultaneous measures with video and search coil recordings across healthy subjects and patients with a wide range of previously identified peripheral vestibular deficits.MethodsHorizontal HIT was recorded simultaneously with vHIT (250 Hz) and search coils (1,000 Hz) in 8 normal subjects, 6 patients with vestibular neuritis, 1 patient after unilateral intratympanic gentamicin, and 1 patient with bilateral gentamicin vestibulotoxicity.ResultsSimultaneous video and search coil recordings of eye movements were closely comparable (average concordance correlation coefficient r(c) = 0.930). Mean VOR gains measured with search coils and video were not significantly different in normal (p = 0.107) and patients (p = 0.073). With these groups, the sensitivity and specificity of both the reference and index test were 1.0 (95% confidence interval 0.69-1.0). vHIT measures detected both overt and covert saccades as accurately as coils.ConclusionsThe video head impulse test is equivalent to search coils in identifying peripheral vestibular deficits but easier to use in clinics, even in patients with acute vestibular neuritis.
| S-EPMC2890997 | biostudies-literature