Impact of Clinician Training Background and Stroke Location on Bedside Diagnostic Test Accuracy in the Acute Vestibular Syndrome - A Meta-Analysis.

OBJECTIVE: Acute dizziness/vertigo is usually due to benign inner-ear causes but is occasionally due to dangerous neurologic ones, particularly stroke. Because symptoms and signs overlap, misdiagnosis is frequent and overuse of neuroimaging is common. We assessed the accuracy of bedside findings to differentiate peripheral vestibular from central neurologic causes. METHODS: We performed a systematic search (MEDLINE and Embase) to identify studies reporting on diagnostic accuracy of physical examination in adults with acute, prolonged dizziness/vertigo ("acute vestibular syndrome" [AVS]). Diagnostic test properties were calculated for findings. Results were stratified by examiner type and stroke location. RESULTS: We identified 6,089 citations and included 14 articles representing 10 study cohorts (n = 800). The Head Impulse, Nystagmus, Test of Skew (HINTS) eye movement battery had high sensitivity 95.3% (95% confidence interval [CI] = 92.5-98.1) and specificity 92.6% (95% CI = 88.6-96.5). Sensitivity was similar by examiner type (subspecialists 94.3% [95% CI = 88.2-100.0] vs non-subspecialists 95.0% [95% CI = 91.2-98.9], p = 0.55), but specificity was higher among subspecialists (97.6% [95% CI = 94.9-100.0] vs 89.1% [95% CI = 83.0-95.2], p = 0.007). HINTS sensitivity was lower in anterior cerebellar artery (AICA) than posterior inferior cerebellar artery (PICA) strokes (84.0% [95% CI = 65.3-93.6] vs 97.7% [95% CI = 93.3-99.2], p = 0.014) but was "rescued" by the addition of bedside hearing tests (HINTS+). Severe (grade 3) gait/truncal instability had high specificity 99.2% (95% CI = 97.8-100.0) but low sensitivity 35.8% (95% CI = 5.2-66.5). Early magnetic resonance imaging (MRI)-diffusion-weighted imaging (DWI; within 24-48 hours) was falsely negative in 15% of strokes (sensitivity 85.1% [95% CI = 79.2-91.0]). INTERPRETATION: In AVS, HINTS examination by appropriately trained clinicians can differentiate peripheral from central causes and has higher diagnostic accuracy for stroke than MRI-DWI in the first 24-48 hours. These techniques should be disseminated to all clinicians evaluating dizziness/vertigo. ANN NEUROL 2023;94:295-308.

Effect of convergence on the horizontal VOR in normal subjects and patients with peripheral and central vestibulopathy.

BACKGROUND: Vestibular compensatory eye movements provide visual fixation stabilization during head movement. The anatomic pathways mediating a normal horizontal vestibulo-ocular reflex (h-VOR), when lesioned, cause spontaneous nystagmus. While previous reports address the effect of convergence on different spontaneous nystagmus types, to our knowledge, a study of acute vestibular nystagmus suppression viewing near targets comparing patients with peripheral or central vestibular lesions has not been previously reported. METHODS: We attempt to clarify potential vestibular and near-reflex interaction by comparing near and far h-VOR gain in 19 healthy controls, six patients with acute/subacute peripheral vestibular lesion (PVL), and one patient with unilateral vestibular nuclear lesion (VNL) in the pontine tegmentum. RESULTS: The horizontal (h)-VOR in normal subjects increased with convergence in both eyes (P = 0.027, P < 0.001). In unilateral PVL patients, gain failed to increase in either direction (P = 0.25, P = 0.47). In contrast, when fixating at 15 cm, the h-aVOR in the VNL lesion, gain did not increase, and a right h-nystagmus developed. Even though we found inability to increase gain in PVL with near target fixation, this did not interfere with h-nystagmus suppression upon converging. Our VNL patient had normal h-nystagmus suppression viewing far distance targets and lacked near target h-nystagmus suppression. CONCLUSION: We hypothesize that normal IO/flocculus pathway suppressed spontaneous nystagmus in PVL. Impaired h-VOR near adaptation in the medial vestibular nucleus was responsible for h-nystagmus direction with fixation block. Additionally, impaired viewing distance estimate contributed to near h-nystagmus suppression failure.

Mild Bilateral Internuclear Ophthalmoplegia: The Diagnostic Role of the Vertical Posterior Canal Vestibulo-Ocular Reflex in Acute Brainstem Demyelination, a Clinical-Radiologic Correlation.

BACKGROUND: The ocular signs of internuclear ophthalmoplegia (INO) with slow, restricted adduction of one eye and abduction nystagmus of the contralateral eye are easily recognized and have a high localizing/lateralizing value. However, subtle INO is difficult to diagnose. Recent reports identified novel vestibular abnormalities in unilateral and bilateral INO. Frequent findings include decreased horizontal and posterior canal gains, and generally relative sparing of both anterior canals. We studied one patient with a subtle bilateral INO, performed serial quantitative saccade (QS) and video head impulse test (vHIT), and correlated clinical-radiological findings caused by acute demyelination. METHODS: Single case study of a 30-year-old man presented with 1 week of painless, binocular, horizontal diplopia in left gaze. We performed 3 serial neurological examination, QS, vHIT, and clinical-MRI correlation (1 pretreatment and 2 post steroid treatment). RESULTS: We found bilateral slow adducting, clinically positive posterior canal HITs, and borderline abducting saccade velocity, without abducting nystagmus. The videonystagmography with fixation block showed bilateral horizontal gaze evoked nystagmus, and vHIT testing confirmed decreased right horizontal and bilateral posterior canal gains. The abnormalities resolved after steroid treatment. MRI showed acute bilateral medial longitudinal fascicle demyelinating lesions. CONCLUSIONS: A bilaterally positive, posterior, canal HIT and slow adduction saccades are localizing findings in bilateral INO, even in the absence of abduction nystagmus. Quantitative confirmation of these findings suggest most frequently an ischemic or demyelinating disorder and are a compelling indication for MRI. This case shows value to testing multiaxial head impulses and performing QS and vHIT in brainstem lesions.

Postinfectious SARS-CoV-2 Opsoclonus-Myoclonus-Ataxia Syndrome.

BACKGROUND: The opsoclonus-myoclonus-ataxia syndrome (OMAS) represents a pathophysiology and diagnostic challenge. Although the diverse etiologies likely share a common mechanism to generate ocular, trunk, and limb movements, the underlying cause may be a paraneoplastic syndrome, as the first sign of cancer, or may be a postinfectious complication, and thus, the outcome depends on identifying the trigger mechanism. A recent hypothesis suggests increased GABAA receptor sensitivity in the olivary-oculomotor vermis-fastigial nucleus-premotor saccade burst neuron circuit in the brainstem. Therefore, OMAS management will focus on immunosuppression and modulation of GABAA hypersensitivity with benzodiazepines. METHODS: We serially video recorded the eye movements at the bedside of 1 patient with SARS-CoV-2-specific Immunoglobulin G (IgG) serum antibodies, but twice-negative nasopharyngeal reverse transcription polymerase chain reaction (RT-PCR). We tested cerebrospinal fluid (CSF), serum, and nasopharyngeal samples. After brain MRI and chest, abdomen, and pelvis CT scans, we treated our patient with clonazepam and high-dose Solu-MEDROL, followed by a rituximab infusion after her formal eye movement analysis 10 days later. RESULTS: The recordings throughout her acute illness demonstrated different eye movement abnormalities. While on high-dose steroids and clonazepam, she initially had macrosaccadic oscillations, followed by brief ocular flutter during convergence the next day; after 10 days, she had bursts of opsoclonus during scotopic conditions with fixation block but otherwise normal eye movements. Concern for a suboptimal response to high-dose Solu-MEDROL motivated an infusion of rituximab, which induced remission. An investigation for a paraneoplastic etiology was negative. CSF testing showed elevated neuron-specific enolase. Serum IgG to Serum SARS-CoV2 IgG was elevated with negative RT-PCR nasopharyngeal testing. CONCLUSION: A recent simulation model of macrosaccadic oscillations and OMAS proposes a combined pathology of brainstem and cerebellar because of increased GABAA receptor sensitivity. In this case report, we report 1 patient with elevated CSF neuronal specific enolase, macrosaccadic oscillations, ocular flutter, and OMAS as a SARS-CoV-2 postinfectious complication. Opsoclonus emerged predominantly with fixation block and suppressed with fixation, providing support to modern theories on the mechanism responsible for these ocular oscillations involving cerebellar-brainstem pathogenesis.

Inflammatory Sixth Nerve Palsy Post-COVID-19 Vaccination: Magnetic Resonance Imaging Findings.

Sixth nerve palsy is the most common post-vaccination oculomotor palsy. It is generally transient with most patients making a complete recovery. We report the case of a 46-year-old healthy male patient who presented with a painless sixth nerve palsy after the second dose of the Pfizer BioNTech COVID-19 vaccine, which recovered over the course of the next month. We confirmed the lesion localisation by demonstrating enhancement of the root exit zone and the cisternal portion of the sixth nerve on sequential magnetic resonance imaging during the symptomatic period. Here, a temporal relationship between vaccine application and diplopia onset suggests an aetiologic relationship. Moreover, the lack of pre-existing medical conditions suggests a post-vaccination inflammatory process.

Paraneoplastic Progressive Downbeat Nystagmus, Ataxia and Sensorineural Hearing Loss due to the ANTI-Kelch-11 Protein Antibody.

ABSTRACT: A 45-year-old man with a history of testicular seminoma treated 8 years earlier presented with chronic progressive truncal and limb ataxia, progressive sensorineural hearing loss, and episodic vertigo. Eye movement and neuro-otology examinations showed localizing abnormalities to the bilateral cerebellar flocculus, vermis, and bilateral cerebellar hemispheres. Audiometric testing showed bilateral symmetric sensorineural hearing loss. There was a normal MRI of the brain. Cerebrospinal fluid (CSF) showed modest lymphocytic pleocytosis, and there was an elevated serum choriogonadotrophic hormone. An abdominal CT scan showed a solitary, large retroperitoneal lymph node, and histopathologic examination of the node biopsy showed granulomatous inflammation without microorganisms; eventually, immunohistochemical markers confirmed the diagnosis of metastatic seminoma. Although normal neuroimaging and inflammatory CSF reaction suggested a paraneoplastic etiology, the initial paraneoplastic antibody testing was negative. Subsequent investigation identified a positive kelch-11 protein antibody, thus confirming the paraneoplastic connection between the metastatic seminoma and the subacute neurologic-cochleovestibular syndrome.

Resolved External Ophthalmoplegia and Hearing Loss in Wernicke's Encephalopathy With Thiamine Replacement.

BACKGROUND: Wernicke encephalopathy (WE) is classically described by a clinical triad consisting of confusion, ataxia, and ophthalmoplegia, but recent reports emphasize a history of malnutrition along with 2 elements of the WE triad (Caine's criteria) to enhance diagnostic sensitivity. The ophthalmoplegia, vestibular, and auditory expeditious improvement with intravenous thiamine usually confirms the diagnosis; serum levels generally provide additional diagnostic certainty. METHODS: Here, we discuss the case of a woman with a distant history of gastric sleeve, poor nutrition and protracted vomiting, who developed acute confusion, imbalance, near-total external ophthalmoplegia (EO), and hearing loss. The baseline thiamine level was 28 πmol/L (Normal: 70-180 πmol/L). We performed serial neurological, vestibular, and audiological examination to document over 5 days, the effect of intravenous (IV) thiamine, and again at 3 months with continued oral supplementation. We provide serial documentation with photographs and video recording of oculomotor abnormalities, audiometric testing, and a video of horizontal head impulse testing, and imaging findings. RESULTS: Over the course of 5 days of IV thiamine supplementation, we demonstrate our patient's resolution of near complete EO. We assessed vestibular paresis with horizontal head impulse testing, after complete resolution of the EO. The initially positive bilateral h-HIT showed decreased gain and overt corrective saccades, it clinically resolved by day 5, but video h-HIT testing demonstrated persistent decreased horizontal vestibulo-ocular reflex (VOR) gain and covert horizontal saccades, which persisted at the 3-month examination. By contrast, the vertical VOR gain was normal without corrective saccades. Bedside audiometry completed during the acute phase demonstrated severely restricted auditory speech comprehension, which normalized 3 months later. Severe truncal ataxia improved as well. CONCLUSIONS: This case is an example of how awareness of the variations in the clinical presentation of WE can be crucial in achieving an early diagnosis and obtaining better outcomes. A history of the poor nutritional status can be an important clue to aid in this early diagnosis.

Eye movements in demyelinating, autoimmune and metabolic disorders.

PURPOSE OF REVIEW: In the last three decades, the use of eye movements and vestibular testing in many neurological disorders has accelerated, primarily because of practical technologic developments. Although the acute vestibular syndrome is a prime example of this progress, more chronic neurologic and systemic disorders have received less attention. We focus here on recent contributions relating vestibular and ocular motor abnormalities in inflammatory, demyelinating, metabolic, and peripheral nervous system disorders RECENT FINDINGS: Vestibular abnormalities have been identified in acute demyelinating neuropathies (AIDP), in novel genetic mutations responsible for CANVAS (cerebellar ataxia, neuropathy vestibular areflexia syndrome), and in other inherited neuropathies (variants of Charcot-Marie-Tooth disease). In addition, there are differentiating characteristics between the most common CNS demyelinating disorders: multiple sclerosis and neuromyelitis optica (NMO). We summarize new information on Vitamin D metabolism in benign paroxysmal positional vertigo (BPPV), followed by a brief review of the vestibular and ocular motor findings in Wernicke's encephalopathy. We conclude with findings in several paraneoplastic/autoimmune disorders. SUMMARY: This literature review highlights the impact of a careful vestibular and ocular motor evaluation in common neurologic disorder, not only for the initial diagnosis but also for monitoring disease and rehabilitation. A careful examination of eye movements and vestibular function, supplemented with new video techniques to quantify the findings, should be part of the standard neurologic examination.

Update on HINTS Plus, With Discussion of Pitfalls and Pearls.

BACKGROUND AND PURPOSE: The team that manages acute vertigo in patients requires multispecialty skills. This special interest article offers a simplified list of common pitfalls to be avoided when applying the HINTS (Head-Impulse, Nystagmus, Test-of-Skew) Plus examination protocol in patients with acute vertigo. Benign paroxysmal positional vertigo is the most frequent cause of positional vertigo. The lack of systematic evaluation of symptom duration and triggers, and/or incomplete target examination, leads to improper diagnosis and management. Pitfalls to avoid and pearls to apply are offered to avoid misclassification of acute vertigo. SUMMARY OF KEY POINTS: Appropriate, expeditious treatment implemented upon diagnostic certainty by the first health professional evaluating the patient is key to a good outcome. The absence of a typical positional nystagmus is particularly concerning for an alternative diagnosis. Misclassification of the type of vertigo leads to potential diagnostic error. The HINTS Plus examination is useful when applied to the correct clinical scenario. The most common misclassification of vertigo relates to an inability to detect spontaneous nystagmus suppressed by visual fixation and subsequent classification and treatment for positional vertigo. The second most common classification relates to inadequate evaluation of the HINTS Plus examination. RECOMMENDATIONS FOR CLINICAL PRACTICE: Through an organized evaluation of the acutely vertiginous patient, common pitfalls in the classification of vertigo can be avoided. Such an evaluation leads to identification of those patients who require canal repositioning maneuvers and those who need referral for evaluation of other causes.

Ipilimumab-induced Adenohypophysitis and Orbital Apex Syndrome: Importance of Early Diagnosis and Management.

Ipilimumab is a novel anti-melanoma agent known to infrequently cause multi-organ autoimmunity. We report a case of pituitary hypophysitis and orbital inflammation followed by an orbital apex syndrome. A 64-year-old woman with a history of skin melanoma, receiving ipilimumab treatment, was seen for near total loss of vision in the right eye and proptosis. Headache of 3-month duration preceded the onset of diplopia followed by severe loss of vision in the right eye. Neuro-ophthalmologic examination was consistent with an orbital apex syndrome. Extensive blood work and magnetic resonance imaging of the brain and orbit suggested an inflammatory process, rather than a metastatic lesion. Accordingly, the patient received high-dose methylprednisolone followed by tapering oral prednisone. At the 6-month follow-up visit, visual acuity on the right eye had significantly improved but diplopia remained, associated with large amplitude esotropia that improved incompletely though while on prednisone. The favourable outcome supported a final diagnosis of ipilimumab-induced inflammatory orbital apex syndrome and clinically silent pituitary adenohypophysitis. The case presented herein highlights unexpected ipilimumab-associated adverse effects and proposes the possibility of and interaction between inflammatory and immune mechanisms.

An Incidental Finding of Ecchordosis Physaliphora in a Case of Abducens Nerve Palsy: Case Report.

Ecchordosis physaliphora (EP) is a rare non-malignant mass that originates from remains of the notochord and is typically asymptomatic. A 42-year-old man presented with sudden onset of painless horizontal diplopia and his neurological exam showed sixth cranial nerve palsy. Magnetic resonance imaging (MRI) identified a non-enhanced retroclival mass (EP) with increased signal intensity on T2 and decreased signal intensity on T1-weighted sequences. He was treated with methylprednisolone, completely recovered in four weeks and has remained symptom free. Conservative management should be attempted before surgery in all cases since symptoms can resolve spontaneously and EP could be an incidental finding.

The Spectrum of Vestibular and Ocular Motor Abnormalities in Thiamine Deficiency.

PURPOSE: The first aim of this review is to summarize recent ocular motor signs in pre-encephalopathy patients with nutritional deficiency at risk of thiamine deficiency. Timely recognition of thiamine depletion in these patients, who may have a normal brain MRI, could lead to appropriate management and prevention of Wernicke's encephalopathy (WE) with full recovery. The second aim is to incorporate recent diagnostic testing on the revised WE diagnostic criteria and the identification of patients who may show slow, partial, or no response to treatment. RECENT FINDINGS: Selective vulnerability of periventricular gray neurons in thiamine deficiency is well known. Involvement of the vestibular and abducens nuclei may precede encephalopathy. Studies have shown mild ophthalmoparesis and bilateral symmetric vestibular loss in thiamine deficiency. Moreover, quantitative data has shown decreased horizontal vestibulo-ocular reflex (VOR) gain and nystagmus, with a favorable response to timely treatment. Ophthalmoparesis, horizontal nystagmus, and decreased gain of the horizontal VOR, sparing the vertical VOR, may be present in the early pre-encephalopathy stage of thiamine deficiency. Rapid response to a loading dose of parenteral thiamine might be seen in some cases and normalization, albeit slower in others. In contrast, analogous to the Korsakoff's syndrome, ocular motor and vestibular abnormalities may show only partial improvement. Future studies in larger populations at risk are needed to confirm the results of these preliminary observations.

Neuroimaging "HINTS" of the Lateral Medullary Syndrome.

A series of neuroimaging studies illustrates many of the key findings of the lateral medullary syndrome.

Visual, Ocular Motor, and Cochleo-Vestibular Loss in Patients With Heteroplasmic, Maternally-Inherited Diabetes Mellitus and Deafness (MIDD), 3243 Transfer RNA Mutation.

BACKGROUND: Mitochondrial encephalopathy, lactic acidosis, and stroke-like symptoms (MELAS) and MIDD (maternally-inherited diabetes mellitus and deafness) are caused by A3243G transfer RNA mutations that affect mitochondrial function. Hearing loss and early onset diabetes mellitus constitute the main MIDD phenotype. Regarding the ophthalmologic manifestations of MIDD, we hypothesized that decreased vestibulo-ocular reflex (VOR) gain in patients with MIDD may contribute to impaired dynamic visual acuity. METHODS: Neuro-ophthalmologic, neuroimaging, and neuro-otologic evaluations were performed in 2 nonrelated patients with MIDD who complained of oscillopsia with head movement. We obtained quantitative recording of the horizontal and the vertical VOR, using the video head impulse test device. RESULTS: In the 2 patients, we detected visual, ocular motor, and vestibular abnormalities. Decreased VOR gain in the planes of all 3 semicircular canals and impaired dynamic visual acuity was demonstrated in both cases. CONCLUSIONS: MIDD patients are primarily recognized by their advanced hearing loss or deafness, early onset diabetes mellitus, and lactic acidosis. Decreased vision in these patients relates primarily to peri-macular retinal atrophy. In addition, loss of vestibular function causes poor dynamic visual acuity. Both patients, in their late fifties, had evidence of progressive central and peripheral nervous system dysfunction.

A Rare Case of Unilateral Progressive Vision Loss and Pachymeningitis.

We describe a 32-year-old man with presumed Vogt-Koyanagi Harada (VKH) syndrome, whose presenting symptoms were headache and progressive loss of vision in the right eye. Neuro-ophthalmic examination showed anterior and posterior uveitis, and retinal detachment in the right eye. Ocular coherence tomography (OCT) showed extensive submacular fluid in the right eye, while the fundus fluorescein angiogram (FFA) confirmed perifoveal retinal pigment epithelium (RPE) disruption and multifocal fluorescein leakage in the right eye. The brain MRI showed a small crescent of dependent fluid layering in the right posterior globe adjacent to the right optic nerve head, and pachymeningeal enhancement of the skull base dura along the clivus.This case demonstrates the utility of brain MRI and OCT findings in the early diagnosis of VKH syndrome, in the absence of prominent clinical signs of meningitis. Aggressive treatment is critical to preserve vision and prevent development of other systemic complications of the disease.

Quantifying the vestibulo-ocular reflex with video-oculography: nature and frequency of artifacts.

Video-oculography devices are now used to quantify the vestibulo-ocular reflex (VOR) at the bedside using the head impulse test (HIT). Little is known about the impact of disruptive phenomena (e.g. corrective saccades, nystagmus, fixation losses, eye-blink artifacts) on quantitative VOR assessment in acute vertigo. This study systematically characterized the frequency, nature, and impact of artifacts on HIT VOR measures. From a prospective study of 26 patients with acute vestibular syndrome (16 vestibular neuritis, 10 stroke), we classified findings using a structured coding manual. Of 1,358 individual HIT traces, 72% had abnormal disruptive saccades, 44% had at least one artifact, and 42% were uninterpretable. Physicians using quantitative recording devices to measure head impulse VOR responses for clinical diagnosis should be aware of the potential impact of disruptive eye movements and measurement artifacts.

Using the Theories of Joseph Babinski to Manage Functional Vision Loss.

OBJECTIVE: To report our use of persuasion to treat patients with functional vision loss and to place them in the context of both Joseph Babinski's theories on hysteria and the current literature on management of functional vision loss. BACKGROUND: Conversion disorders, such as functional vision loss, can develop in response to a traumatic event. Recent functional imaging studies have found that, rather than being malingerers, patients with conversion disorders show changes within neuromodulatory pathways, suggesting organic dysfunction rather than a purely psychological disorder. METHODS: We conducted a retrospective analysis of 8 consecutive patients (7 female, 1 male; mean age 16 years) who had presented to a university-based neuro-ophthalmology clinic with vision loss from a conversion disorder. The patients had been given a lengthy visual task to perform at home, with the suggestion that their vision would improve by the time they completed the task. RESULTS: All 8 patients had evidence of a dissociation between real and perceived visual acuity and fields. All the patients performed the assigned visual task at home, and all either reported improvement or showed improved visual function at follow-up. CONCLUSIONS: A century after Joseph Babinski proposed using persuasion in managing patients with vision loss from a conversion disorder, we report that his method remains a viable and pathophysiologically sound option. Future case-controlled studies that include functional magnetic resonance imaging, other neurophysiologic imaging, and neuroradiographic evaluation may strengthen the correlation between persuasion therapy and recovery of normal vision.