Relationship between the Presence of Nystagmus in the Fourth Position of the Epley Maneuver and Treatment Efficacy for PSC BPPV: A Prospective Study.

OBJECTIVE: To investigate whether a specific nystagmus observed during the Epley maneuver can enable immediate reassessment of patients, eliminating the need for deferred diagnosis. STUDY DESIGN: Prospective cohort. SETTING: Tertiary center. PATIENTS: Patients with posterior semicircular canal (PSC) benign paroxysmal positional vertigo (BPPV) diagnosed by the Dix-Hallpike test between March 2022 and March 2023. INTERVENTIONS: All patients were treated with the Epley maneuver. The presence and the characteristics of the nystagmus were recorded in each of the four intermediate positions of the maneuver. Fifteen minutes later, all patients were reevaluated with the Dix-Hallpike test to determine the therapeutic success. MAIN OUTCOME MEASURES: Outcome of the Epley maneuver and its relationship with nystagmus characteristics during the four positions of the maneuver. RESULTS: Sixty-six patients (77.3% female) were included in the study, of which 66.7% exhibited right PSC BPPV. Therapeutic success of the first Epley maneuver was 74.2%. Almost one third (30.3%) of patients presented with nystagmus in the second and third positions of the Epley maneuver. All patients with down-beating and torsional nystagmus toward the opposite direction of the diagnostic nystagmus in the fourth position of the Epley maneuver needed a second rehabilitative maneuver. None of the patients without nystagmus in this fourth position remained with active BPPV after the first Epley maneuver. CONCLUSIONS: The presence of nystagmus in the fourth position of the Epley maneuver appears to have a high predictive value, reducing waiting time for a second diagnostic maneuver. Its absence may exempt subsequent reevaluation.

Guidelines for reasonable and appropriate care in the emergency department 3 (GRACE-3): Acute dizziness and vertigo in the emergency department.

This third Guideline for Reasonable and Appropriate Care in the Emergency Department (GRACE-3) from the Society for Academic Emergency Medicine is on the topic adult patients with acute dizziness and vertigo in the emergency department (ED). A multidisciplinary guideline panel applied the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence and strength of recommendations regarding five questions for adult ED patients with acute dizziness of less than 2 weeks' duration. The intended population is adults presenting to the ED with acute dizziness or vertigo. The panel derived 15 evidence-based recommendations based on the timing and triggers of the dizziness but recognizes that alternative diagnostic approaches exist, such as the STANDING protocol and nystagmus examination in combination with gait unsteadiness or the presence of vascular risk factors. As an overarching recommendation, (1) emergency clinicians should receive training in bedside physical examination techniques for patients with the acute vestibular syndrome (AVS; HINTS) and the diagnostic and therapeutic maneuvers for benign paroxysmal positional vertigo (BPPV; Dix-Hallpike test and Epley maneuver). To help distinguish central from peripheral causes in patients with the AVS, we recommend: (2) use HINTS (for clinicians trained in its use) in patients with nystagmus, (3) use finger rub to further aid in excluding stroke in patients with nystagmus, (4) use severity of gait unsteadiness in patients without nystagmus, (5) do not use brain computed tomography (CT), (6) do not use routine magnetic resonance imaging (MRI) as a first-line test if a clinician trained in HINTS is available, and (7) use MRI as a confirmatory test in patients with central or equivocal HINTS examinations. In patients with the spontaneous episodic vestibular syndrome: (8) search for symptoms or signs of cerebral ischemia, (9) do not use CT, and (10) use CT angiography or MRI angiography if there is concern for transient ischemic attack. In patients with the triggered (positional) episodic vestibular syndrome, (11) use the Dix-Hallpike test to diagnose posterior canal BPPV (pc-BPPV), (12) do not use CT, and (13) do not use MRI routinely, unless atypical clinical features are present. In patients diagnosed with vestibular neuritis, (14) consider short-term steroids as a treatment option. In patients diagnosed with pc-BPPV, (15) treat with the Epley maneuver. It is clear that as of 2023, when applied in routine practice by emergency clinicians without special training, HINTS testing is inaccurate, partly due to use in the wrong patients and partly due to issues with its interpretation. Most emergency physicians have not received training in use of HINTS. As such, it is not standard of care, either in the legal sense of that term ("what the average physician would do in similar circumstances") or in the common parlance sense ("the standard action typically used by physicians in routine practice").

[Nystagmus in Children - a Survey]. / Nystagmus bei Kindern ­ eine Übersicht.

Nystagmus describes an involuntary, periodic movement of one or both eyes. About 1/600 children and adolescents have nystagmus, most of them idiopathic infantile nystagmus (IIN), also called "congenital nystagmus", which can be caused by mutations in the FRMD7 gene. Other frequent forms of nystagmus are latent nystagmus, which is usually associated with infantile strabismus, and nystagmus associated with albinism. Sometimes difficult to distinguish in young infants is a sensory nystagmus, where a defect in the visual system reduces vision and causes nystagmus. Causes include retinal dystrophies, congenital stationary night blindness and structural ocular defects including optic nerve hypoplasia or dense bilateral congenital cataracts. Unilateral nystagmus can be the sign of an anterior visual pathway lesion. Seesaw nystagmus may be associated with suprasellar and mesodiencephalic lesions and - rarely - with retinal dystrophies.The ophthalmology plays a key role in identifying the form of nystagmus. Children with new onset nystagmus, with spasmus nutans, with vertical or unilateral nystagmus and those with seesaw nystagmus require neurologic evaluation including imaging of the brain.The treatment of nystagmus depends on the underlying cause. Even minor refractive errors should be corrected, contact lenses offer advantages over glasses.Gabapentin and memantine, possibly also carbonic anhydrase inhibitors, are effective in treating IIN, nystagmus in albinism and sensory nystagmus. Nevertheless, pharmacologic treatment of nystagmus is rarely used in children; the reasons are the limited effects on vision, the need for lifelong therapy, and potential side effects. Eye muscle surgery (Anderson procedure, Kestenbaum procedure) can correct a nystagmus-related anomalous head posture. The concept of "artifical divergence" of Cüppers may help to decrease nystagmus intensity in patients whose nystagmus dampens with convergence. The four-muscle-tenotomy, which involves disinsertion and reinsertion of the horizontal muscles at the original insertion of both eyes, has a proven but limited positive effect on visual acuity.

A dynamical method to objectively assess infantile nystagmus based on eye tracking. A pilot study.

PURPOSE: The purpose of this research is to propose a new method for the easy, inexpensive and objective quantification of nystagmus using eye-tracking records collected during a simple reading task that could be implantable in clinical practice to assess patients with nystagmus. METHODS: This is a prospective, observational pilot study. Eye movements of 4 nystagmus patients and 9 healthy children during a reading task (a paragraph with 82 words) on a 15'' monitor were collected and compared. Data are time series indicating the gaze position on the screen. Two quantifiers were proposed: IndS (based on the speed of movements) and IndF (based on the variation of the gaze trajectory). RESULTS: The indices proposed reflect differences in the behavior of eye movements between the two groups. Nystagmus patients present higher values of IndS - indicating smaller number of slow movements (16% of movements with speeds <0.33 1/s for nystagmus and 85% for the control group, with p = 0.01) - and higher values of IndF - indicating higher gaze fluctuation (p = 0.01). Differences were not related with reading speed as show the mean and standard deviation: the nystagmus group required 115±45 s to complete the task and the control group 151±85 s; p = 0.73. CONCLUSIONS: The proposed indices provide a new method that allows an objective assessment of nystagmus, with potential use in clinical and research practice to improve the follow-up of patients by monitoring the nystagmus over time or treatment.

[The value of high intensity stimulation training of semicircular canal of SRM-â £ vertigo diagnosis and treatment system in the rehabilitation of vestibular neuritis].

Objective:To evaluate the value of high intensity stimulation training of semicircular canal of SRM-Ⅳ vertigo diagnosis and treatment system in the rehabilitation of vestibular neuritis. Methods:To analyze 68 patients with vestibular neuritis treated in Department of Otorhinolaryngology Head and Neck Surgery, Shijiazhuang People's Hospital from January 2020 to January 2021, conduct spontaneous nystagmus and head toss test, and perform spontaneous nystagmus and rotation test of SRM-Ⅳvertigo system, compare the positive rate of the side of disease was between the two. To randomly divide 68 patients into treatment group 1, 2 and control group, the control group with drugs, treatment group 1 with drugs and vestibular rehabilitation training exercise, treatment group 2 with additional high intensity stimulation training of semicircular canal at one week after onset, on the basis of drug therapy and vestibular rehabilitation training exercise. At 2 weeks and 1 month, through swivel chair test negative rate, DHI score, compare the efficacy of the three groups. Results:Spontaneous nystagmus combined with head toss test confirmed 80.9% of the side of the disease, spontaneous nystagmus and rotation test of SRM-Ⅳ vertigo system confirmed 100%, the difference is statistically significant（P<0.05）. Compared with the control group and the treatment group 1, the negative conversion rate of the rotation test in the treatment group 2 at the second week and the first month of treatment, the difference is statistically significant（P<0.05, the second week χ²=6.474, the first month χ²=6.245）; the DHI score of treatment group 2 was statistically significant compared with that of control group and treatment group 1 at the second week and first month of treatment（P<0.05, the second week F=13.578, the first month F=28.599）. Conclusion:SRM-Ⅳ vertigo diagnosis and treatment system semicircular canal high intensity stimulation training has a certain role in the rehabilitation treatment of vestibular neuritis. It is simple to operate, patient tolerance and compliance are good, and it is worth promoting.

[Benign paroxysmal positional vertigo: diagnostic and therapeutic maneuvers]. / Vertige positionnel paroxystique bénin: manœuvres diagnostiques et thérapeutiques.

Benign paroxysmal positional vertigo (BPPV) is a very frequent cause of vertigo. BPPV occurs when there is a pathological presence of otolith debris in the semicircular canals. The history of BPPV is often typical, with recurrent episodes of vertigo lasting less than one minute, triggered by head movements, without other neurological signs. The characteristics of the nystagmus observed during the diagnostic maneuvers of Hallpike and Supine Head Roll test allow the identification of the affected semicircular canal and the choice of the appropriate therapeutic maneuver, which in most cases will lead to recovery. This article presents the diagnostic and therapeutic maneuvers.

Le vertige positionnel paroxystique bénin (VPPB) est une cause très fréquente de vertige. Le VPPB se produit en cas de présence pathologique de débris d'otolithes dans les canaux semi-circulaires (CSC). L'anamnèse du VPPB est souvent typique, à savoir des épisodes de vertige récidivants d'une durée de moins d'une minute, déclenchés par les mouvements de la tête, sans autre signe neurologique. Les caractéristiques du nystagmus observé lors des manœuvres diagnostiques de Dix-Hallpike et du Supine Head Roll Test permettent d'identifier le CSC atteint et d'opter pour la manœuvre thérapeutique adéquate, qui permettra dans la majeure partie des cas la guérison. Cet article présente les manœuvres diagnostiques et thérapeutiques.

Complex benign horizontal canal positional vertigo: new perceptual management.

OBJECTIVE: Horizontal semicircular canal site pathology of benign paroxysmal positional vertigo demonstrating three types of nystagmi on positional test were studied. We have attempted to design a protocol for its diagnosis and treatment. METHODS: 320 patients of HSC-BPPV were subjected to two types of positional tests. Of these, patients with bilateral steady apogeotropic nysatgmus were treated with VAV modification of Semont's maneuver. Patients with unsteady or changing apo/geotropic signs were converted into steady geotropic ones by repetitive positional tests; followed by barbecue maneuver with forced prolong positioning. RESULTS: Overall 88% of patients had a total recovery. 92% of patients with geotropic nystagmus showed no symptoms after second maneuveral sitting. 85% of patients with apogeotropic nystagmus recovered fully after third maneuveral sitting. CONCLUSIONS: Correct identification of subtypes of HSC-BPPV is based on provoked nystagmus by positional tests. After locating the site and side on the basis of nystagmic pattern, physician can apply the appropriate PRM. LEVEL OF EVIDENCE: II a.

A Story of Discovery and Change: What We Learned from Studying Nystagmus in Infancy and Childhood.

The last 40 years of clinical experience and investigation of nystagmus in infancy and childhood have resulted in a clearer understanding and characterization of the disorder and provided guidelines for the beneficial effects of increased medical, optical, and surgical treatments. Our modern understanding is due to the results of contribution by scientists and clinicians representing vision, neurology, bioengineering, genetics, and pediatrics. From this group, a new classification system was developed. The routine use of eye-movement recordings (EMR) and its characteristics have made the largest contribution to this increased knowledge. The value of EMR is due to the observation of specific waveforms, which are the basis for classification, neuro-pathophysiology, effect on vision, and a measure of nystagmus response to treatment. Successful treatment of the visual system is now directed toward associated afferent system abnormalities (decreased acuity, amblyopia, ametropia, retinal and optic pathway disease, and photophobia), centrally at the neuronal level responsible for the oscillations (oral and topical medications) and peripherally to reduce the underlying oscillation (eye-muscle surgery and botulinum toxin). Evidence over the last 40 years has shown that these treatments result in increased spatial acuity, contrast sensitivity, visual recognition time, motion processing, gaze-dependent visual acuity, and anomalous head posturing. The hope of this review is that clinicians now provide hope for these patients and families and can be counseled that nystagmus treatment is available.

Antivertiginous Effect of Caloric Stimulation for Acute Peripheral Vertigo.

OBJECTIVE: To clarify therapeutic effect of caloric stimulation for acute peripheral vertigo. PATIENTS: Two patients with acute peripheral vertigo accompanied by spontaneous nystagmus. INTERVENTIONS: Therapeutic. MAIN OUTCOMES AND MEASURES: Changes in the maximum slow phase velocity of spontaneous nystagmus and subjective vertigo. RESULTS: Reduction in the maximum slow phase velocity of spontaneous nystagmus and mitigation of subjective vertigo was observed in both patients. CONCLUSION: Caloric stimulation could be one potential option as a suppressant for acute peripheral vertigo.

Current Therapies in Patients With Posterior Semicircular Canal BPPV, a Systematic Review and Network Meta-analysis.

OBJECTIVE: To compare the efficacy of different treatments for posterior semicircular canal benign paroxysmal positional vertigo (PC-BPPV) by using direct and indirect evidence from existing randomized data. METHODS: Randomized case-control studies that compared the efficacy of various nonsurgical treatments in PC-BPPV patients at 1 week and 1 month of follow-up were comprehensively screened. Bayesian network meta-analysis was performed to evaluate direct and indirect treatment comparisons. We further conducted subgroup pairwise meta-analysis to explore the inconsistency between comparisons of the Epley versus a sham maneuver and the Epley versus the Semont maneuver. RESULTS: A total of 41 parallel, randomized controlled studies were included. The Epley with vestibular rehabilitation (EVR), Epley, Semont and Hybrid maneuvers were effective in eliminating nystagmus during a Dix-Hallpike test at 1 week of follow-up (odds ratios [ORs]: 11.41-23.8, 95% credible interval [CrI]: excluding null), among which EVR showed the best efficacy (the surface area under the cumulative ranking curves [SUCRA] = 77.5%). However, at 1 month of follow-up, only the Semont (rank first, SUCRA = 76.1%) and Epley maneuvers (rank second, SUCRA = 65.3%) were effective in eliminating nystagmus during a Dix-Hallpike test. In the pairwise subgroup meta-analysis, for patients younger than 55 years of age, the efficacy of the Epley maneuver was comparable to that of the Semont maneuver [rate ratio (RR): 0.99, 95% confidence interval (CI): 0.93-1.05]; for patients with a longer duration before treatment, the effect of the Epley maneuver was equivalent to that of a sham maneuver (RR: 1.07, 95% CI: 0.90-1.29). CONCLUSION: Among the 12 types of PC-BPPV treatments, the Epley, Semont, EVR, and Hybrid maneuvers were effective in eliminating nystagmus during a Dix-Hallpike test for PC-BPPV at 1 week of follow-up, whereas only the Epley and Semont maneuvers were effective at 1 month of follow-up. The duration before treatments and the age of patients might contribute to the efficacy of treatments.

Current-dependent ocular tilt reaction in deep brain stimulation of the subthalamic nucleus: Evidence for an incerto-interstitial pathway?

BACKGROUND AND PURPOSE: The aim was to characterize a combined vestibular, ocular motor and postural syndrome induced by deep brain stimulation (DBS) of the subthalamic nucleus in a patient with Parkinson's disease. METHODS: In a systematic DBS programming session, eye, head and trunk position in roll and pitch plane were documented as a function of stimulation amplitude and field direction. Repeat ocular coherence tomography was used to estimate ocular torsion. The interstitial nucleus of Cajal (INC), zona incerta (ZI) and ascending vestibular fibre tracts were segmented on magnetic resonance imaging using both individual and normative structural connectomic data. Thresholded symptom-associated volumes of tissue activated (VTA) were calculated based on documented stimulation parameters. RESULTS: Ipsilateral ocular tilt reaction and body lateropulsion as well as contralateral torsional nystagmus were elicited by the right electrode in a current-dependent manner and subsided after DBS deactivation. With increasing currents, binocular tonic upgaze and body retropulsion were observed. Symptoms were consistent with an irritative effect on the INC. Symptom-associated VTA was found to overlap with the dorsal ZI and the ipsilateral vestibulothalamic tract, while lying rather distant to the INC proper. A ZI-to-INC 'incerto-interstitial' tract with contact to the medial-uppermost portion of the VTA could be traced. CONCLUSION: Unilateral stimulation of INC-related circuitry induces an ipsilateral vestibular, ocular motor and postural roll-plane syndrome, which converts into a pitch-plane syndrome when functional activation expands bilaterally. In this case, tractography points to an incerto-interstitial pathway, a tract previously only characterized in non-human primates. Directional current steering proved useful in managing this rare side effect.

The role of the reversed nystagmus during Zuma maneuver in patients treated for geotropic lateral canal benign paroxysmal positional vertigo.

INTRODUCTION: The geotropic variant of lateral canal BPPV occurs due to free floating otoconia in the non ampullary arm of this canal. Several repositioning maneuvers were effective to treat patients with this variant. We have previously proposed that the Zuma maneuver, first described for apogeotropic lateral canal BPPV, could also be effective for the geotropic variant as we believe that adopting a single maneuver may help the neurotological clinical practice. MATERIAL AND METHODS: Fifteen patients with geotropic lateral canal BPPV were enrolled and treated with Zuma maneuver. Patients were reevaluated 1 h after a single maneuver. RESULTS: All patients showed a nystagmus beating to the affected side in step I of Zuma maneuver that reversed its direction in step II. Besides, all patients achieved immediate resolution of vertigo and positional nystagmus after the application of the maneuver. CONCLUSIONS: The reversal of the nystagmus in step II of Zuma maneuver could be considered as a good prognostic indicator of the successful of this maneuver in patients with geotropic lateral canal BPPV. Moreover, despite the small sample of patients, Zuma maneuver was effective on short-term follow up for geotropic LC-BPPV after a single application.

Clinical significance of down-beating nystagmus and postural control loss when returning to a sitting position during the canalith repositioning maneuver.

Patients with benign paroxysmal positional vertigo (BPPV) occasionally experience severe dizziness, could not maintain the sitting posture, and then fall onto or off the examination table when they return to the sitting position, which is the last step of the barbecue maneuver and Epley maneuver (EM); down-beating nystagmus is also observed. This study aims to investigate the clinical characteristics and significance of these findings. We retrospectively reviewed video data showing nystagmus and medical records of adult patients diagnosed with canalolithiasis of the horizontal canal and the posterior canal (PC) BPPV who underwent barbecue maneuver and EM, respectively, in outpatient clinics from April 2014 to March 2019. This study included 112 patients (28 horizontal canal BPPV and 94 PC BPPV cases). Among the 122 BPPV cases, only 14 (14.9%) were analyzed, due to their occurrence during EM. Down-beating nystagmus appeared at 3.6 seconds on average after returning to the sitting position, and the patients fell onto or off the examination table at 4.4 seconds on average after the onset of the nystagmus. The average duration of the down-beating nystagmus was 20.3 seconds. In all 14 cases, no nystagmus was induced by the Dix-Hallpike test performed again after EM, confirming that the treatment was successful. During the EM, down-beating nystagmus and falling onto or off the examination table occurred in approximately 15% of cases. As the risk of falls increases, the patient should be secured immediately after EM. Moreover, it can be inferred that the findings occur when otoconia in the PC enter the utricle, suggesting a successful treatment.

A novel maneuver for diagnosis and treatment of torsional-vertical down beating positioning nystagmus: anterior canal and apogeotropic posterior canal BPPV.

INTRODUCTION: In patients with benign paroxysmal positional vertigo, BPPV; a torsional-vertical down beating positioning nystagmus can be elicited in the supine straight head-hanging position test or in the Dix-Hallpike test to either side. This type of nystagmus can be explained by either an anterior canal BPPV or by an apogeotropic variant of the contralateral posterior canal BPPV Until now all the therapeutic maneuvers that have been proposed address only one possibility, and without first performing a clear differential diagnosis between them. OBJECTIVE: To propose a new maneuver for torsional-vertical down beating positioning nystagmus with a clear lateralization that takes into account both possible diagnoses (anterior canal-BPPV and posterior canal-BPPV). METHODS: A prospective cohort study was conducted on 157 consecutive patients with BPPV. The new maneuver was performed only in those with torsional-vertical down beating positioning nystagmus with clear lateralization. RESULTS: Twenty patients (12.7%) were diagnosed with a torsional-vertical down beating positioning nystagmus. The maneuver was performed in 10 (6.35%) patients, in whom the affected side was clearly determined. Seven (4.45%) patients were diagnosed with an anterior canal-BPPV and successfully treated. Two (1.25%) patients were diagnosed with a posterior canal-BPPV and successfully treated with an Epley maneuver after its conversion into a geotropic posterior BPPV. CONCLUSION: This new maneuver was found to be effective in resolving all the cases of torsional-vertical down beating positioning nystagmus-BPPV caused by an anterior canal-BPPV, and in shifting in a controlled way the posterior canal-BPPV cases of the contralateral side into a geotropic-posterior-BPPV successfully treated during the followup visit. Moreover, this new maneuver helped in the differential diagnosis between anterior canal-BPPV and a contralateral posterior canal-BPPV.

[Characteristics of nystagmus and its therapeutic effect in the reduction of posterior semicircular canal benign paroxysmal positional vertigo].

Objective:By observing the nystagmus forms at different positions during Epley reduction in patients with posterior semicircular canal benign parochial positional vertigo（PC-BPPV）, to compare the effects of the first reduction, and to further summarize the possible causes of reduction failure and the prognosis of patients with different nystagmus forms. Methods:A retrospective analysis of 191 PC-BPPV patients diagnosed with PC-BPPV showed that 95 cases had positive nystagmus during the reduction process（group A）, 69 cases had no nystagmus （group B）, and 27 cases had reverse nystagmus （group C）. All the patients were diagnosed by G-Force BPPV and were treated through simulative Epley CRP. The form of nystagmus and the effect of the first reduction were compared. Results:The first reduction effect of group A was better than that of group C（P<0.05）. The reduction effect of group B was better than that of group C（P<0.05）. There was no significant difference in the reduction effect between group A and group B（P>0.05）. Conclusion:The form of nystagmus in the reduction process of PC-BPPV has a certain guiding significance for the evaluation of the first reduction effect and the successful reduction. The reverse nystagmus during the reduction process indicates a poor reduction effect.

Effects of transtympanic intermittent pressure therapy using a new tympanic membrane massage device for intractable Meniere's disease and delayed endolymphatic hydrops: a prospective study.

BACKGROUND: The retrospective study showed that the effect of the middle ear pressure treatment by the tramstympanic membrane massage (TMM) device was similar to that of the Meniett device. OBJECTIVES: The new TMM device named EFET device was prospectively evaluated in patients with Meniere's disease (MD) and delayed endolymphatic hydrops (DEH) and we compared the effects to the Meniett device. MATERIALS AND METHODS: 23 ears of 19 patients were treated with an EFET device, and 17 ears of 15 patients were treated with the Meniett device. All patients suffering from intractable MD and DEH were treated for 4 months. The insertion of a transtympanic ventilation tube was necessary for the Meniett device, but not the EFET device. RESULTS: In patients treated by the EFET and Meniett devices, the frequency of vertigo significantly improved after treatment. The distribution of vertigo outcomes at 4 months after treatment did not differ between patients treated with the both devices. CONCLUSIONS AND SIGNIFICANCE: Middle ear pressure treatment by the EFET device is effective and provides minimally invasive options for intractable MD and DEH like the Meniett device.

Downbeat nystagmus: a clinical review of diagnosis and management.

PURPOSE OF REVIEW: This review will extensively cover the clinical manifestations, causes, diagnostic evaluation, and management strategies of downbeat nystagmus (DBN). RECENT FINDINGS: Historically, MRI to assess for structural lesions at the cervicomedullary junction has been the primary diagnostic test in the evaluation of DBN since the 1980s. In recent years, there is increasing awareness of nonstructural causes of DBN including gluten ataxia, nutritional deficiencies, and paraneoplastic syndromes, among others. Medical management with aminopyridines has become first-line therapy in addition to disease-specific therapies. SUMMARY: DBN is a common form of acquired nystagmus and the differential diagnosis remains broad, including both benign and potentially fatal causes. For practical purposes, the causes can be categorized as structural vs. nonstructural with MRI as the ideal, initial diagnostic study to differentiate the two. General therapeutic options include pharmacotherapy to enhance Purkinje cell function, strabismus surgery or prisms to shift null points, and behavioural changes. Disease-specific treatment is necessarily broad, though a significant proportion of patients will be idiopathic.

Fixational eye movements abnormalities and rate of visual acuity and stereoacuity improvement with part time patching.

Residual amblyopia is seen in 40% of amblyopic patients treated with part-time patching. Amblyopic patients with infantile onset strabismus or anisometropia can develop fusion maldevelopment nystagmus syndrome (FMNS). The purpose of this study was to understand the effects of presence of FMNS and clinical subtype of amblyopia on visual acuity and stereo-acuity improvement in children treated with part-time patching. Forty amblyopic children who had fixation eye movement recordings and at least 12 months of follow-up after initiating part-time patching were included. We classified amblyopic subjects per the fixational eye movements characteristics into those without any nystagmus, those with FMNS and patients with nystagmus without any structural anomalies that do not meet the criteria of FMNS or idiopathic infantile nystagmus. We also classified the patients per the clinical type of amblyopia. Patching was continued until amblyopia was resolved or no visual acuity improvement was noted at two consecutive visits. Children with anisometropic amblyopia and without FMNS have a faster improvement and plateaued sooner. Regression was only seen in patients with strabismic/mixed amblyopia particularly those with FMNS. Patients with FMNS had improvement in visual acuity but poor stereopsis with part-time patching and required longer duration of treatment.

Nystagmus and Vertigo in Acute Vestibular Migraine Attacks: Response to Non-Invasive Vagus Nerve Stimulation.

OBJECTIVE: Vestibular migraine (VM) is the most common neurologic cause of vertigo in adults, but there are no currently-approved rescue therapies. This study describes the benefits of non-invasive vagus nerve stimulation (nVNS) on vertigo, headache, and nystagmus during VM attacks. METHODS: Case series of four VM patients who were evaluated during acute VM episodes in a tertiary referral neurology clinic between February 2019 and January 2020. They underwent bedside neuro-otologic examination, and graded the severity of vertigo and headache using a 10-point visual-analog scale (VAS; 0-no symptoms, 10-worst ever symptoms), before and 15 minutes after nVNS. RESULTS: Average vertigo severity was 5 (median 4.5) before, and 1.5 (median 0.5) after nVNS. Mean headache severity (three patients) before treatment was 4 (median 4), and 0.7 (median 0) after. Spontaneous right-beating nystagmus (Patient 1) nystagmus, upbeat nystagmus (Patient 2), and positional nystagmus (Patient 3) resolved with nVNS. Baseline left-beating nystagmus in Patient 4 from previous vestibular neuritis damped during acute VM but returned to baseline following nVNS. In all four patients, ictal nystagmus resolved, and examination findings returned to baseline. CONCLUSIONS: This study suggests nVNS may ameliorate vertigo and headache, as well as nystagmus associated with VM attacks. Larger, sham device-controlled studies are needed to elucidate the benefits of nVNS in VM.