Four-hour-delayed 3D-FLAIR MRIs in patients with acute unilateral peripheral vestibulopathy.

OBJECTIVE: Conventionally, MRI aids in differentiating acute unilateral peripheral vestibulopathy/vestibular neuritis (AUPV/VN) from mimickers. Meanwhile, the diagnostic utility of MRIs dedicated to the inner ear remains to be elucidated for diagnosing AUPV/VN. METHODS: We prospectively recruited 53 patients with AUPV/VN (mean age ± SD = 60 ± 15 years, 29 men). Initial MRIs were performed with a standard protocol, and an additional axial 3D-fluid-attenuated inversion recovery (3D-FLAIR) sequence was obtained 4 h after intravenous injection of gadoterate meglumine. Abnormal enhancement was defined as a signal intensity that exceeded the mean + 2SD value on the healthy side. The findings of neurotologic evaluation and MRIs were compared. RESULTS: Overall, the inter-rater agreement for gadolinium enhancement was 0.886 (Cohen's kappa coefficient). Enhancement was observed in 26 patients (49%), most frequently in the vestibule (n = 20), followed by the anterior (n = 12), horizontal (HC, n = 8), posterior canal (n = 5), and superior (n = 3) and inferior (n = 1) vestibular nerves. In multivariable logistic regression analysis, the enhancement was associated with decreased HC gain in video head-impulse tests (p = 0.036), increased interaural difference in ocular vestibular-evoked myogenic potentials (p = 0.001), and a longer onset-to-MRI time span (p = 0.024). The sensitivity and specificity were 92.3% and 81.5%, respectively, with an area under the curve of 0.90 for predicting gadolinium enhancement. INTERPRETATION: Robust gadolinium enhancement was observed on 4-hour-delayed 3D-FLAIR images in nearly half of the patients with AUPV/VN, with a good correlation with the results of neurotologic evaluation. The positivity may be determined by the extent of vestibular deficit, timing of imaging acquisition, and possibly by the underlying etiology causing AUPV/VN. MRIs may aid in delineating the involved structures in AUPV/VN.

Neck rigidity: a pitfall for video head-impulse tests in Parkinson's disease.

Video head impulse tests (video-HITs) are commonly used for vestibular evaluation; however, the results can be contaminated by various artifacts, including technical errors, recording problems, and participant factors. Although video-HITs can be used in patients with Parkinson's disease (PD), the effect of neck rigidity has not been systematically investigated. This study aimed to investigate the effect of neck rigidity on video-HIT results in patients with PD. We prospectively recruited 140 consecutive patients with PD (mean age ± standard deviation = 68 ± 10 years, 69 men) between September 2021 and April 2024 at Korea University Medical Center. The video-HIT results were compared with those of 19 age- and sex-matched healthy participants. Neck rigidity was stratified as a subdomain of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor part (MDS-UPDRS-III). In 59 patients, the vestibulo-ocular reflex (VOR) gain was overestimated in at least one canal plane (58/140, 41%), mostly in the anterior canal (AC, n = 44), followed by the horizontal (HC, n = 15) and posterior canals (PC, n = 7). VOR gain overestimation was also observed in patients with no (18/58, 35%), subtle (20/58, 34%), or mild (17/58, 29%) neck rigidity. Multivariable logistic regression analysis showed that VOR overestimation was positively associated with neck rigidity (odds ratio [OR] [95% confidence interval] = 1.51 [1.01-2.25], p = 0.043). The head velocities of patients decreased during head impulses for the AC (p = 0.033 for the right AC; p = 0.014 for the left AC), whereas eye velocities were similar to those of healthy participants. Our findings suggest that neck rigidity may be a confounder that can contaminate video-HIT results. Thus, the results of video-HITs, especially for the AC, should be interpreted with the context of head velocity during head impulses in patients with neck rigidity.

Expanding Clinical Spectrum of Anti-GQ1b Antibody Syndrome: A Review.

Importance: The discovery of the anti-GQ1b antibody has expanded the nosology of classic Miller Fisher syndrome to include Bickerstaff brainstem encephalitis, Guillain-Barré syndrome with ophthalmoplegia, and acute ophthalmoplegia without ataxia, which have been brought under the umbrella term anti-GQ1b antibody syndrome. It seems timely to define the phenotypes of anti-GQ1b antibody syndrome for the proper diagnosis of this syndrome with diverse clinical presentations. This review summarizes these syndromes and introduces recently identified subtypes. Observations: Although ophthalmoplegia is a hallmark of anti-GQ1b antibody syndrome, recent studies have identified this antibody in patients with acute vestibular syndrome, optic neuropathy with disc swelling, and acute sensory ataxic neuropathy of atypical presentation. Ophthalmoplegia associated with anti-GQ1b antibody positivity is complete in more than half of the patients but may be monocular or comitant. The prognosis is mostly favorable; however, approximately 14% of patients experience relapse. Conclusions and Relevance: Anti-GQ1b antibody syndrome may present diverse neurological manifestations, including ophthalmoplegia, ataxia, areflexia, central or peripheral vestibulopathy, and optic neuropathy. Understanding the wide clinical spectrum may aid in the differentiation and management of immune-mediated neuropathies with multiple presentations.

Ocular motor and vestibular dysfunction in central nervous system lymphoma.

BACKGROUND AND PURPOSE: Diagnosis of lymphoma involving the central nervous system (CNS) is challenging. This study aimed to explore the abnormal vestibular and ocular motor findings in CNS lymphoma. METHODS: A retrospective search of the medical records identified 30 patients with CNS lymphoma presenting ocular motor and vestibular abnormalities from four neurology clinics of university hospitals in South Korea (22 men, age range 14-81 years, mean 60.6 ± 15.2). The demographic and clinical features and the results of laboratory, radiological and pathological evaluation were analyzed. RESULTS: Patients presented with diplopia (13/30, 43%), vestibular symptoms (15/30, 50%) or both (2/30, 7%). In 15 patients with diplopia, abnormal ocular motor findings included ocular motor nerve palsy (n = 10, 67%), internuclear ophthalmoplegia (n = 2, 13%), external ophthalmoplegia (n = 2, 13%) and exophoria (n = 1, 7%). The vestibular abnormalities were isolated in 14 (82%) of 17 patients with vestibular symptoms and included combined unilateral peripheral and central vestibulopathy in three from lesions involving the vestibular nuclei. CNS lymphoma involved the brainstem (53%), cerebellum (33%), leptomeninges (30%), deep gray nuclei (23%) or cranial nerves (17%). Two patients showed the "double-panda" sign by involving the midbrain. CONCLUSIONS: This study expands the clinical and radiological spectra of CNS lymphoma. Neuro-ophthalmological and neuro-otological evaluation may guide the early diagnosis of CNS lymphoma.

Evolution of Vestibular Findings During and Between the Attacks of Meniere Disease: Update.

Purpose of Review: The diagnosis of Meniere disease (MD) has based on characteristics of vertigo and findings of audiologic evaluation. This review focuses on the recent findings of the evolution of vestibular function and their underlying physiology during and between the attacks of MD and thus aims to help identify this common disorder with many faces according to the phase. Recent Findings: During the attacks, the direction of spontaneous nystagmus changes over time, beating initially toward the affected ear (irritative nystagmus), then toward the healthy ear (paretic nystagmus), and finally back toward the affected ear again (recovery nystagmus). Apart from these direction changes, atypical forms of spontaneous nystagmus, such as downbeat, discordant horizontal-torsional, and aperiodic alternating nystagmus, can be observed. Head impulse tests (HITs) are mostly normal during the irritative/recovery phases, but positive in more than half of patients during the paretic phase. By contrast, caloric tests are usually abnormal irrespective of the phases, although paradoxical caloric hyper-responsiveness can be observed in 18% of patients during the irritative/recovery phases. Thus, dissociation in the findings of caloric tests-HITs can be observed during and between the attacks. Horizontal head shaking tends to augment spontaneous nystagmus during each phase, while skull vibration mostly induces nystagmus beating toward the healthy ear irrespective of the phases. During the attacks, ocular vestibular-evoked myogenic potentials (VEMPs) may be enhanced, whereas cervical VEMPs are usually decreased during stimulation of the involved ear. Summary: Recognizing these evolutions of vestibular findings during and between the attacks of MD would provide insights into its pathophysiology and aid in treatments and diagnosis.

The semicircular canal function is preserved with little impact on falls in patients with mild Parkinson's disease.

INTRODUCTION: Postural instability is a cardinal symptom of Parkinson's disease (PD), which suggests the vestibular system may be affected in PD. This study aimed to determine whether vestibular dysfunction is associated with the risk of falls in PD. METHODS: We prospectively recruited patients with de-novo PD at a tertiary medical center between December 2019 and March 2023. During initial assessment, each patient was queried about falls within the preceding year. All patients underwent evaluation of video head-impulse tests (video-HITs), motion analysis, mini-mental state examination (MMSE), and Montreal Cognitive Assessment (MOCA). We determined whether head impulse gain of the vestibulo-ocular reflex (VOR) was associated with clinical severity of PD or risk of falls. RESULTS: Overall, 133 patients (mean age ± SD = 68 ± 10, 59 men) were recruited. The median Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor part (MDS-UPDRS-III) was 23 (interquartile range = 16-31), and 81 patients (61 %) scored 2 or less on the Hoehn and Yahr scale. Fallers were older (p = 0.001), had longer disease duration (p = 0.001), slower gait velocity (p = 0.009), higher MDS-UPDRS-III (p < 0.001) and H&Y scale (p < 0.001), lower MMSE (p = 0.018) and MOCA scores (p = 0.001) than non-fallers. Multiple logistic regression showed that MDS-UPDRS-III had a positive association with falling (p = 0.004). Falling was not associated with VOR gain (p = 0.405). The VOR gain for each semicircular canal showed no correlation with the MDS-UPDRS-III or disease duration. CONCLUSIONS: The semicircular canal function, as determined by video-HITs, is relatively spared and has little effect on the risk of falls in patients with mild-to-moderate PD.

Effects of pupil size in video head-impulse tests.

The results of video head impulse tests (video-HITs) may be confounded by data artifacts of various origins, including pupil size and eyelid obstruction of the pupil. This study aimed to determine the effect of these factors on the results of video-HITs. We simulated ptosis by adopting pharmacological dilatation of the pupil in 21 healthy participants (11 women; age 24-58 years). Each participant underwent video-HITs before and after pupillary dilatation using 0.5% tropicamide. We assessed the changes in the vestibulo-ocular reflex (VOR) gain, corrective saccade amplitude, and frequency of eyelid flicks. After pupillary dilatation, the VOR gain decreased for both right (RAC; 1.12 [Formula: see text] 0.12 vs. 1.01 [Formula: see text] 0.16, p = 0.011) and left anterior canals (LACs; 1.15 [Formula: see text] 0.13 vs. 0.96 [Formula: see text] 0.14, p < 0.001), and right posterior canal (RPC, 1.10 [Formula: see text] 0.13 vs. 0.98 [Formula: see text] 0.09, p = 0.001). The corrective saccade amplitudes also decreased significantly for all four vertical canals. The frequency of eyelid flicks, however, did not change. The changes of VOR gain were positively correlated with the lid excursion in RPC (r = 0.629, p = 0.002) and LPC (r = 0.549, p = 0.010). Our study indicates that eyelid position and pupil size should be considered when interpreting the results of video-HITs, especially for the vertical canals. Pupils should be shrunk in a very well-lit room, and artifacts should be prevented by taping or lifting the eyelids as required during video-HITs.

Recurrence and long-term outcomes of Tolosa-Hunt syndrome.

BACKGROUND AND PURPOSE: Tolosa-Hunt Syndrome (THS) is a rare disorder, and detailed clinical information and treatment outcomes have yet to be fully elucidated. This study aims to investigate the clinical features and factors associated with the treatment outcomes of THS, as defined by the established diagnostic criteria. METHODS: This study retrospectively recruited 91 patients with a diagnosis of THS from 2003 to 2020. We analyzed the clinical features and outcomes, the initial treatment response, recurrences, and the final treatment response. RESULTS: Isolated ocular motor nerve palsy was the most common (82.4%) finding of ophthalmoplegia, involving the oculomotor nerve in more than half of the cases (52.0%). The MRI lesions were mostly observed in the cavernous sinus (94.5%) with an extracavernous extension in about one-third of them. Five patients showed only extracavernous lesions. A total of 25 (27.5%) patients experienced recurrence. Recurrence occurred during steroid tapering as part of the initial treatment in seven, while in 18 patients, it happened after the successful termination of the initial treatment. However, all patients achieved complete remission at the final. Age was associated with a decrease in initial symptom duration (HR = 1.023, CI = 1.004-1.044) as well as an increase in recurrence-free duration (HR = 0.944, CI = 0.911-0.978). High-dose corticosteroid treatment was associated with a decrease in initial symptom duration (HR = 1.642, CI = 1.001-2.695) and total treatment duration (HR = 2.203 CI = 1.302-3.730). CONCLUSIONS: THS can recur frequently especially in younger but have a favorable prognosis. High-dose corticosteroids can be an effective initial treatment and reduce the total treatment duration.

Scale for Ocular Motor Disorders in Ataxia (SODA) in Patients with Multiple System Atrophy.

A clinical scale fully dedicated to evaluating ocular motor abnormalities is required for now. We investigated the utility of a recently developed Scale for Ocular motor Disorders in Ataxia (SODA) in patients with multiple system atrophy (MSA). We prospectively assessed SODA in consecutive patients with MSA between August 2021 and August 2023 at the Korea University Medical Center. The results of the clinical exam-based SODA were compared with those measured using video-oculography (VOG-guided SODA). We also compared the findings with other established clinical scales targeting patients with MSA, including the Unified Multiple System Atrophy Rating Scale (UMSARS) I-II, Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor part (UPDRS-III), Scale for Assessment of Rating of Ataxia (SARA), Composite Autonomic Symptom Score-31 (COMPASS-31), and Composite Autonomic Severity Score (CASS). Twenty patients were enrolled in our study (17 with cerebellar-type MSA and three with Parkinson-type MSA). Scores ranged from 1 to 14 (median [interquartile range (IQR)] = 8 [5-10]). Among the subscales, saccades had a median score of 2.5 (IQR = 1-3), followed by ocular pursuit (1 [0-1]), nystagmus (1 [0-2]), saccadic intrusions (1 [0-1]), vestibulo-ocular reflex (VOR) (0.5 [0-1]), ocular alignment (0 [0-1]), and VOR cancellation (1 [0-1]). The clinical-exam-based SODA (p = 0.020) and VOG-guided SODA (p = 0.034) positively correlated with disease duration. No correlation was found between clinical exam-based SODA and other scales. Skew deviation, gaze-evoked nystagmus, VOR cancellation, and smooth pursuit had the highest precision among the items. Ocular misalignment and spontaneous and positional nystagmus were frequently false positive and were poorly detected with clinical exam-based SODA. Six patients with repeated evaluation exhibited higher scores, along with deterioration documented on other clinical scales. The SODA can reliably predict neurodegeneration as an additional clinical surrogate in MSA.

Clinical Features and Neurotologic Findings in Patients With Acute Unilateral Peripheral Vestibulopathy Associated With Antiganglioside Antibody.

BACKGROUND AND OBJECTIVES: Anecdotal studies have reported the presence of antiganglioside antibodies in acute unilateral peripheral vestibulopathy (AUPV). This study aimed to determine the prevalence, clinical characteristics, and neurotologic findings of AUPV associated with antiganglioside antibodies. METHODS: Serum antigangliosides were measured in consecutive patients with AUPV according to the Bárány Society criteria during the acute and recovery phases in a referral-based university hospital in South Korea from September 2019 to January 2023. Clinical characteristics and neurotologic findings were compared between those with and without antiganglioside antibodies. The results of video-oculography, video head impulse and bithermal caloric tests, and other neurotologic evaluations including ocular and cervical vestibular-evoked myogenic potentials and subjective visual vertical were compared between the 2. MRIs dedicated to the inner ear were also conducted when considered necessary. RESULTS: One hundred five patients (mean age ± SD = 60 ± 13 years, 57 male) were included for analyses. During the acute phase, 12 patients (12/105, 11%) were tested positive for serum antiganglioside antibodies, including anti-GQ1b immunoglobulin (Ig) G (n = 5) or IgM (n = 4), anti-GM1 IgM (n = 3), and anti-GD1a IgG (n = 1, including 1 patient with a positive anti-GQ1b antibody). Patients with antiganglioside antibodies showed lesser intensity of spontaneous nystagmus (median [interquartile range] = 1.8 [1.2-2.1] vs 3.4 [1.5-9.5], p = 0.003) and a lesser degree of canal paresis (30 [17-47] vs 58 [34-79], p = 0.028) and gain asymmetry of the vestibulo-ocular reflex for the horizontal semicircular canal during head impulse tests (0.07 [-0.04 to 0.61] vs 0.36 [0.18-0.47], p = 0.032) than those without antibodies. Negative conversion of antibodies and vestibular recovery were observed in most patients (6/8, 75%). Among 30 patients with AUPV with 4-hour delayed 3D fluid-attenuated inversion recovery dedicated to the inner ear, gadolinium enhancement was observed in 18 (18/30, 60%), either in the vestibule (n = 9), semicircular canal (n = 6), or vestibular nerve (n = 5). The positivity rates based on specific antibodies could not be determined due to limited sample sizes. DISCUSSION: The association between antiganglioside antibodies and AUPV suggests an immune-mediated mechanism in acute vestibular failure and extends the clinical spectrum of antiganglioside antibody syndrome.

Analyses of Head-Impulse Tests in Patients With Posterior Circulation Stroke and Vestibular Neuritis.

BACKGROUND AND OBJECTIVES: The interpretation of video head-impulse tests (video-HITs) can often be complicated, limiting their clinical utility in acute vestibular syndrome. We aimed to determine video-HIT findings in patients with posterior circulation strokes (PCSs) and vestibular neuritis (VN). METHODS: We retrospectively analyzed the results of video-HITs in 59 patients with PCS. Irrespective of the actual lesion revealed later on MRIs, ipsilateral and contralateral sides were assigned according to the direction of slow phase of spontaneous nystagmus (SN). Then, the patterns of video-HIT findings were classified according to the vestibulo-ocular reflex (VOR) gain for the horizontal canals; (1) ipsilaterally positive, (2) contralaterally positive, (3) bilaterally normal, and (4) bilaterally positive. The abnormal responses were further defined into (5) wrong-way saccades, (6) perverted, and (7) early acceleration followed by premature deceleration. We also analyzed the asymmetry of the corrective saccadic amplitude between the sides, calculated from the sum of cumulative saccadic amplitudes on both sides. The results were compared with video-HIT results from 71 patients with VN. RESULTS: Video-HITs were normal in 32 (54%), ipsilaterally positive in 11 (19%), bilaterally positive in 10 (17%), and contralaterally positive in 6 (10%) patients with PCS. Wrong-way saccades were more frequently observed in VN than in PCS (31/71 [44%] vs 5/59 [8%], p < 0.001). Saccadic amplitude asymmetry was greater in VN than in PCS (median 100% [interquartile range 82-144, 95% CI 109-160] vs 0% [-29 to 34, -10 to 22, p < 0.001]). When differentiating VN from PCS, the sensitivity was 81.7%, and specificity was 91.5% at the cutoff value of 71% for saccadic amplitude asymmetry with an area under the curve (AUC) of 0.91 (95% CI 0.86-0.97). The AUC for saccadic amplitude asymmetry was larger than that for the ipsilateral VOR gain (p = 0.041) and other parameters. DISCUSSION: Patients with PCS may show various head-impulse responses that deviate from the findings expected in VN, which include normal, contralaterally positive, and negative saccadic amplitude asymmetry (i.e., greater cumulative saccadic amplitude contralaterally). A thorough analysis of corrective saccades in video-HITs can improve the differentiation of PCS from VN even before MRIs.

Augmented ocular vestibular-evoked myogenic potentials in postural orthostatic tachycardia syndrome.

PURPOSE: To delineate the association between otolith function and changes in mean orthostatic blood pressure (BP) and heart rate (HR) in patients with postural orthostatic tachycardia syndrome (POTS). METHODS: Forty-nine patients with POTS were prospectively recruited. We analyzed the results of ocular vestibular-evoked myogenic potentials (oVEMPs) and cervical vestibular-evoked myogenic potentials (cVEMPs), as well as head-up tilt table tests using a Finometer. The oVEMP and cVEMP responses were obtained using tapping stimuli and 110 dB tone-burst sounds, respectively. We measured maximal changes in 5-s averaged systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) within 15 s and during 10 min after tilting. We compared the results with those of 20 age- and sex-matched healthy participants. RESULTS: The n1-p1 amplitude of oVEMPs was larger in patients with POTS than in healthy participants (p = 0.001), whereas the n1 latency (p = 0.280) and interaural difference (p = 0.199) did not differ between the two. The n1-p1 amplitude was a positive predictor for POTS (odds ratio 1.07, 95% confidence interval 1.01-1.13, p = 0.025). Body weight (p = 0.007) and n1-p1 amplitude of oVEMP (p = 0.019) were positive predictors for ΔSBP15s in POTS, whereas aging was a negative predictor (p = 0.005). These findings were not observed in healthy participants. CONCLUSIONS: Augmented utricular inputs may be associated with a relative predominance of sympathetic over vagal control of BP and HR, especially for an early response during orthostasis in patients with POTS. Overt sympathoexcitation due to exaggerated utricular input and lack of readaptation may be associated with the pathomechanism of POTS.