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 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.
Various neurotologic findings can be observed in stroke involving the brainstem. Analyses of the neurotologic findings are important in brainstem stroke since it can have negative diffusion-weighted image, as well as, presenting with acute vestibular syndrome in isolation without any associated neurologic deficits. In this review we discuss the neurotologic findings from lesion involving (1) the medial vestibular nucleus, (2) nucleus prepositus hypoglossi, (3) inferior cerebellar peduncle, (4) medial longitudinal fasciculus, (5) rostral interstitial nucleus of the medial longitudinal fasciculus, (6) interstitial nucleus of Cajal, and (7) middle and (8) superior cerebellar peduncles. It is important to recognize these specific neurotologic findings depending on the neural structures involved that may guide early detection and proper management.
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A Case of Ramsay Hunt Syndrome Showing Central Findings due to Brainstem Involvement Min Hyuk Lee, Min-Beom Kim Research in Vestibular Science.2023; 22(4): 120. CrossRef
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
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
Down-beat nystagmus in peripheral vestibulopathy may rarely occur in selective involvement of inferior division. Diagnosis of isolated inferior vestibular neuritis is based on torsional down-beating spontaneous nystagmus, abnormal head-impulse test for the posterior semicircular canal, and abnormal cervical vestibular evoked myogenic potentials (cVEMPs) with normal bithermal caloric tests and ocular vestibular evoked myogenic potentials (oVEMPs). Herein we report a 50-year-old male patient with spontaneous down-beat nystagmus who demonstrated vestibular dysfunction involving only the posterior semicircular canal. The patient showed normal results in the bithermal caloric test, the oVEMPs and cVEMPs test. Video head impulse test showed decreased gain and corrective saccades only in the posterior semicircular canal. This case is significant in showing that peripheral dizziness with spontaneous down-beating nystagmus can occur as a result of an abnormality involving only a single semicircular canal.
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.
Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating autoimmune disease of central nervous system characterized by relapsing attacks that target the optic nerves and spinal cord, as well as aquaporin-4 (AQP4) enriched periventricular brain regions. The area postrema (AP), located in the dorsal medulla, is the chemosensitive vomiting center and has high AQP-4 expression. The AP syndrome with unexplained hiccups, nausea, and vomiting is one of the core clinical characteristics in the NMOSD and maybe the first presenting symptom. We experienced a 25-year-old woman presented with intractable vomiting, dizziness and oscillopsia. Upbeat nystagmus detected on the bedside examination led to comprehensive neurological workups including magnetic resonance imaging, and she was diagnosed as the AP syndrome. Ten months later, she experienced a recurrence as a longitudinally extensive transverse myelitis and the diagnosis was finally compatible with NMOSD without AQP4-IgG. NMOSD, especially the AP syndrome, should be considered in any dizzy patient with intractable vomiting, and detailed neuro-otologic and neuro-ophthalmologic examinations are warranted for the correct diagnosis.