Arnold Chiari malformation is a disease which is characterized by herniation of a portion of the cerebellum through the foramen magnum. Symptoms vary depending on the extent of the affected area, including posterior neck pain, upper limb pain, paralysis, paresthesia, weakness, dizziness, and ataxia. Among the patients presenting with dizziness, nystagmus is frequently observed, which is primarily characterized by down-beating nystagmus. We experienced a 42- years-old female patient presented with vertigo and gait disturbance, who were diagnosed with type 1 Arnold-Chiari malformation and treated by surgical decompression.
Objectives This study was performed to investigate the efficacy of the fixation index (FI) of the bithermal caloric test for differentiating brain lesions in vestibular disorder.
Methods We reviewed the medical records of 286 consecutive dizzy patients who underwent brain magnetic resonance imaging (MRI) and the bithermal caloric test at department of otorhinolarnygology. Central vestibulopathy (CVP) was defined as when corresponding lesion was identified on brain MRI, otherwise peripheral vestibulopathy (PVP) was defined. The FI was defined as the mean slow phase velocity (SPV) with fixation divided by the mean SPV without fixation, and failure was indicated when the FI exceeded 70%.
Results The CVP confirmed by brain MRI and PVP were 16.8% and 83.2%, respectively. The most common CVPs were cerebellopontine angle tumor (n=19, 39.6%) and chronic cerebellar infarction (n=18, 37.5%). There were 23 cases of CVP (47.9%) and 47 cases of PVP (19.7%) with abnormal number of FI in at least two of the four caloric irrigations. The FI score of right cool (RC), left cool (LC), and right warm (RW) were also increased significantly in patients with CVP (p=0.031 at RCFI, p=0.014 at LCFI, p=0.047 at RWFI, and p=0.057 at LWFI; Mann-Whitney U-test).
Conclusions If two or more abnormal FIs are detected during bithermal caloric testing, there is a high likelihood of CVP. Consequently, additional brain MRI may be necessary for further evaluation.
Objectives The objective of this study was to analyze vestibulocochlear function results in patients identified with isolated semicircular canal (SCC) hypofunction using the video head impulse test (vHIT).
Methods A retrospective review was conducted on the clinical records of 123 patients diagnosed with isolated SCC hypofunction based on vHIT results. Among these patients, 72 had isolated posterior SCC (PSCC) hypofunction, 25 had isolated lateral SCC (LSCC) hypofunction, and 26 had isolated anterior SCC (ASCC) hypofunction. Descriptive analyses were performed on various vestibulocochlear tests including pure tone audiometry, sinusoidal harmonic acceleration (SHA), spontaneous nystagmus (SN), head-shaking nystagmus (HSN), caloric testing, and cervical vestibular evoked myogenic potential, with results analyzed separately for each SCC hypofunction group.
Results The study found that 66.0% of the evaluated patients exhibited abnormal results in at least one vestibulocochlear function test. PSCC hypofunction patients showed a significantly higher incidence of hearing loss compared to ASCC and LSCC hypofunction patients. LSCC hypofunction patients exhibited higher rates of corrective saccade, phase asymmetry of SHA, and SN abnormalities compared to other SCC hypofunction patients. Additionally, the rates of corrective saccade and phase asymmetry of SHA were also higher in LSCC hypofunction patients. ASCC hypofunction patients demonstrated significantly higher rates of normal corrective saccade, phase lead of SHA, and SN.
Conclusions The analysis of this study suggests that even in cases where vHIT indicates isolated SCC hypofunction, additional vestibulocochlear function tests should be conducted to identify any associated vestibulocochlear dysfunctions. This highlights the importance of comprehensive evaluation to accurately diagnose and manage patients with SCC hypofunction.
Benign paroxysmal positional vertigo (BPPV) is the most common cause of positional vertigo and nystagmus. Direction-changing positional nystagmus (DCPN), which refers to the change in the direction of nystagmus with different head positions, is a well-known characteristic of horizontal semicircular canal BPPV. The supine head roll test is commonly used to diagnose horizontal canal BPPV. However, persistent geotropic DCPN observed during this test cannot be explained by conventional mechanisms of canalolithiasis or cupulolithiasis. The concept of a “light cupula” has been proposed to account for this unique nystagmus. In this review, we summarize the historical background, clinical features and diagnostic methods, presumed mechanisms, and treatment approaches of the light cupula phenomenon based on the available literatures up to date.
Seesaw nystagmus (SSN) is characterized by conjugate torsional nystagmus with opposite vertical components in the two eyes. The waveform may be pendular or jerk (hemi-seesaw nystagmus, HSSN), in which the slow phase corresponds to one half-cycle and the quick phase to the other. Pendular SSN and HSSN have distinct clinical presentations and underlying causes. The pathophysiology of pendular SSN may be instability of visuovestibular interactions, while the underlying mechanism for HSSN may be related to the ocular tilt reaction or an imbalance in vestibular pathways. We report a patient with HSSN due to unilateral mesodiencephalic infarction that becomes apparent during visual fixation only.
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Midbrain lesion-induced disconjugate gaze: a unifying circuit mechanism of ocular alignment? Maximilian U. Friedrich, Laurin Schappe, Sashank Prasad, Helen Friedrich, Michael D. Fox, Andreas Zwergal, David S. Zee, Klaus Faßbender, Klaus-Ulrich Dillmann Journal of Neurology.2024;[Epub] CrossRef
Objectives This study aimed to investigate clinical significance of a head-bending test in benign paroxysmal positional vertigo (BPPV) involving the posterior semicircular canal (PC-BPPV).
Methods We retrospectively recruited 256 patients with unilateral PC-BPPV between January 2016 and December 2021, and assessed the clinical characteristics of patients showing head-bending nystagmus (HBN).
Results Of 256 patients, 138 (53.9%) showed HBN. Most patients (n=136, 98.6%) had downbeat nystagmus with (n=38) or without (n=98) torsional component. The remaining two patients had pure upbeat and torsional nystagmus, respectively. The torsional component was directed to the contralesional side in all. Between patients with and without HBN, there were no significant differences in clinical characteristics such as age, lateralization, types of BPPV (canalolithiasis or cupulolithiasis), and success rate of repositioning maneuver.
Conclusions Head-bending test may be useful in predicting the diagnosis and lateralization of PC-BPPV.
Objectives The aim of this study was to develop a filtering algorithm for raw nystagmus images and a diagnostic assistive algorithm using a principal component analysis (PCA) to distinguish the different types of benign paroxysmal positional vertigo (BPPV).
Methods Fifteen video clips of clinical data with typical nystagmus patterns of BPPV (13 cases) and with normal nystamgmus (two cases) were preprocessed when applied the thresholding, morphology operation, residual noise filtering, and center point extraction stages. We analyzed multiple data clusters in a single frame via a PCA; in addition, we statistically analyzed the horizontal and vertical components of the main vector among the multiple data clusters in the canalolithiasis of the lateral semicircular canal (LSCC) and the posterior semicircular canal (PSCC).
Results We obtained a clear imaginary pupil and data on the fast phases and slow phases after preprocessing the images. For a normal patient, a round shape of clustered dots was observed. Patients with LSCC showed an elongated horizontal shape, whereas patients with PSCC showed an oval shape at the (x, y) coordinates. The scalar values (mm) of the horizontal component of the main vector when performing a PCA between the LSCC- and PSCC-BPPV were substantially different (102.08±20.11 vs. 32.36±12.52 mm, respectively; p=0.0012). Additionally, the salar ratio of horizontal to vertical components in LSCC and PSCC exhibited a significant difference (16.11±10.74 mm vs. 2.61±1.07 mm, respectively; p=0.0023).
Conclusions The data of a white simulated imaginary pupil without any background noise can be a separate monitoring option, which can aid clinicians in determining the types of BPPV exhibited. Therefore, this analysis algorithm will provide assistive information for diagnosis of BPPV to clinicians.
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Development of An Algorithm for Slippage-Induced Motion Artifacts Reduction in Video-Nystagmography Yerin Lee, Young Joon Seo, Sejung Yang Research in Vestibular Science.2022; 21(4): 104. CrossRef
Dissociated vertical-torsional nystagmus is a unique form of nystagmus characterized by conjugate torsional but disparate vertical components. It has been mainly reported in internuclear ophthalmoplegia or medial medullary lesion involving the medial longitudinal fasciculus (MLF). The patterns of the nystagmus may be explained by a disruption of vestibulo-ocular reflex pathways from vertical semicircular canal or utriculo-ocular reflex within the MLF, but it is debatable. We described a dissociated upbeat-torsional nystagmus in a patient with vestibular nucleus infarction without involvement of MLF.
Objectives During caloric irritation, the spinning/rotating sensation is predominant. However, there is no report on the temporal relationship between caloric nystagmus and perception.
Methods Consecutive 57 participants underwent bithermal caloric test in the dizziness clinic of Chungnam National University Hospital from February 2018 to September 2018. For vestibular perception, we asked the subject to report feelings of rotation and/or linear sensation during each warm and cold water irrigation period. Besides routine caloric parameters, the duration of nystagmus and vestibular sensation were analyzed.
Results In most participants, the caloric nystagmus preceded the vestibular sensation (79.6% in right warm, 83.3% in left warm, 88.5% in right cool, and 84.6% in left cool stimuli). The precedence of perception was observed in 5 normal persons and 15 patients with vestibular migraine (n=4), unilateral vestibulopathy (n=3), and Menière’s disease (n=2), multiple systemic atrophy (n=2), cerebellar ataxia (n=2), vertebrobasilar insufficiency (n=1), and post-earthquake dizziness (n=1). The mean latency between nystagmus and perception was 11.7 seconds. And the duration of nystagmus was longer than that of perception in all conditions. Non-spinning sensations during the caloric test were also observed in some participants (26.8% in right warm, 30.3% in left warm, 29.1% in right cool, and 24.1% in left cool stimuli).
Conclusions During the bithemal alternate caloric test, various vestibular perception and temporal relationship between perception and nystagmus suggest the bithermal caloric stimulation does not reflect only the signal originating from the horizontal canal pathway. A further validation study is needed.
The upward deviation could be explained by loss of inhibitory inputs from the cerebellum onto the brainstem anterior semicircular canal projections for upward vestibulo-ocular reflex, which would lead to an upward bias in static eye position. Therefore, upward gaze deviation has been reported in comatose patients after resuscitation and diffuse cerebrocerebellar damage sparing the brainstem. Herein, we report a patient with ingestion of glufosinate ammonium presented with cerebellar ataxia and ocular motor findings suggestive of cerebellum involvement such as upward gaze tendency, spontaneous downbeat, gaze-evoked nystagmus, perverted head impulse test, and impaired smooth pursuit.
Objectives Light cupula is characterized by persistent geotropic direction-changing positional nystagmus in a supine head-roll test. The purpose of this study is to investigate if hearing level is influenced by the change of head position in light cupula under the assumption that relative density difference similarly occurs between the tectorial membrane and endolymph.
Methods Twelve patients with unilateral light cupula who underwent positional audiometry were included in this study. Pure tone thresholds were compared among three head positions.
Results Hearing threshold in pure tone audiometry (PTA) of the affected ear was not different from that of the healthy ear. PTA thresholds of the affected side were not significantly different in three head positions; upright seating, cochlear apex-up, and cochlear apex-down positions.
Conclusions Although positional change of nystagmus direction is the most significant clinical feature of light cupula, positional change of hearing level was not observed in those patients. The lack of positional influence on hearing may be explained as follows: (1) the heavier endolymph phenomenon occurs only in the vestibular end organ without involving the cochlea; (2) the light cupula phenomenon is more likely to occur due to light debris mechanism rather than heavier endolymph or lighter cupula mechanism; and (3) the effects of light cupula could be modified by outer hair cells, which work for tuning in the cochlea, even though light tectorial membrane or heavy endolymph occurs.
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Light cupula phenomenon: a systematic review Nilüfer Bal, Melike Altun, Elif Kuru, Meliha Basoz Behmen, Ozge Gedik Toker The Egyptian Journal of Otolaryngology.2022;[Epub] CrossRef
Objectives The aim of this paper was to determine if a correlation exists between video head impulse test (vHIT) and electronystagmography with caloric test (ENG). More specifically, comparison of covert and overt value from vHIT test with cold and warm stimulation value from ENG test.
Methods Retrospective study of our single institue from the period of January 2015 to January 2017 enrolled 91 patients. Patients were divided into 3 groups by their diagnosis of either vestibular neuritis (VN), Meniere disease, or sudden sensorineural loss with vertigo accordingly. Each of the patients’ both ENG and vHIT data were recorded and parameters were evaluated.
Results VN group was the only group to show a significant correlation between canal paresis (CP) with covert and overt saccades. Further analysis was done in the VN group and result showed covert saccade showing a larger area under the receiver operation characteristic curve value (0.77) compared to overt saccades (0.70), implying that covert saccade is a more accurate parameter for the prediction of the CP value. Furthermore, a positive correlation was seen between the gain value and the cold caloric stimulation value as well as between warm caloric stimulation value.
Conclusions The value of our study lies in the fact that we have attempted to find a correlation between different parameters of 2 different vestibular tests. We concluded that the evaluation of overt nystagmus by the bedside head thrust test is inappropriate for predicting CP, and a vHIT is required to accurately evaluate vestibular function.
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A Comparative Analysis of the Vestibulocochlear Function in Patients with Isolated Semicircular Canal Hypofunction Using a Video Head Impulse Test Yu Jung Park, Min Young Lee, Ji Eun Choi, Jae Yun Jung, Jung Hwa Bahng Research in Vestibular Science.2023; 22(2): 34. CrossRef
Ramsay Hunt syndrome is an acquired paralysis of the face specifically caused by a varicella-zoster virus infection in the facial nerve. Other cranial nerves including vestibulo-cochlear disturbance can be affected. Herein we reported a case of Ramsay Hunt syndrome with atypical vestibular syndrome. Although central vestibular signs including direction changing post head-shaking nystagmus or normal head impulse test are generally meaningful, clinicians need to be careful to interpret them because some findings can be observed not only in cases of central disorders but also in peripheral disorders. Clinical findings such as distinct ear pain and close observation of vesicles are important to diagnose Ramsay Hunt syndrome.
Ataxia with ocular motor apraxia type 2 (AOA2) is an autosomal recessive disorder that is characterized by adolescent-onset gait ataxia, peripheral neuropathy, ocular apraxia, and cerebellar atrophy. A 19-year-old male with AOA2 from a novel SETX mutation showed distinct oculomotor abnormalities that included spontaneous and gaze-induced downbeat nystagmus, impaired smooth pursuit, and reversed catch-up saccades during horizontal head impulse tests, as well as peripheral neuropathy involving the lower extremities and mild slowing of frontal processing. He also showed positional hemiseesaw nystagmus in the supine and straight head-hanging positions. Positional hemiseesaw nystagmus is a new manifestation of hereditary cerebellar ataxia and may be explained by a gravity-dependent position-induced error in estimating the tilt in the roll plane due to dysfunction of the tilt-estimator circuit.
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A Case of AOA2 With Compound Heterozygous SETX Mutations Hee Jin Chang, Ryul Kim, Minchae Kim, Jangsup Moon, Man Jin Kim, Han-Joon Kim Journal of Movement Disorders.2022; 15(2): 178. CrossRef
A 57-year-old woman presented with sudden onset of whirling vertigo associated with nausea and vomiting. The neurological examination showed left-beating horizontal nystagmus on the lying-down test and right-beating horizontal nystagmus on the head bending test. Geotropic direction-changing horizontal nystagmus was demonstrated on both sides during the supine roll test. Benign paroxysmal positional vertigo (BPPV) was the most common vestibular disorder in patients after head trauma. The authors experienced a case of right horizontal canal BPPV occurred after a yoga practice, thereby we report the case with a review of the related literatures.