Effect of nystagmus on VEP-based objective visual acuity estimates.

In order to determine the effect of nystagmus on objective visual acuity (VA) estimates, we compared subjective (VApsych) and objective (VEP, VAVEP) VA estimates in participants with nystagmus. For this purpose, 20 participants with nystagmus (NY) caused by idiopathic infantile nystagmus, albinism, achiasma or acquired nystagmus were recruited in this study. Estimates of BCVA (best corrected visual acuity) were determined psychophysically (VApsych; FrACT, Freiburg visual acuity test) and electrophysiologically (VAVEP; EP2000) according to ISCEV (International Society of Clinical Electrophysiology of Vision) guidelines. For each participant the eye with the stronger fixation instability [Nidek microperimeter (MP-1), Nidek Instruments] was included for further analysis. VApsych vs VAVEP were compared via paired t-tests and the correlation of the difference between VApsych and VAVEP (∆VA) vs the degree of fixation instability was tested with Pearson correlation (r). We found VAVEP to be better than VApsych [by 0.12 Logarithm of the Minimum Angle of Resolution (logMAR); mean ± standard error (SE) of VAVEP vs VApsych: 0.176 ± 0.06 vs. 0.299 ± 0.06, P = 0.017] and ∆VA to be correlated linearly with the degree of fixation instability (r2 = 0.21,p = 0.048). In conclusion, on average we report a small VA overestimation, around 1 line, for VAVEP compared to VApsych in NY. This overestimation depended on the magnitude of the fixation instability. As a rule of thumb, a reduction of the fixation probability in the central 4° from 100 to 50% leads on average to a VAVEP overestimation of around 0.25 logMAR, i.e. 2.5 lines.

Horizontal Pendular Nystagmus and Ataxia Secondary to Severe Hypomagnesemia.

Background: Severe hypomagnesemia is an increasingly recognized cause of acute and reversible cerebellar ataxia, often accompanied by cerebellar oculomotor signs such as jerky horizontal or downbeat nystagmus and very rarely ocular flutter. Phenomenology Shown: This video illustrates horizontal pendular nystagmus in a patient with acute onset cerebellar ataxia associated with severe hypomagnesemia. Educational value: Acquired pendular nystagmus can be distinguished from macrosaccadic oscillations and ocular flutter in that the former is composed of two slow phases of equal velocity and the latter of two fast phases of saccadic type with or without intersaccadic interval, respectively. It is most commonly associated with demyelinating, toxic, metabolic, and genetic disorders, but has not been reported in association with severe hypomagnesemia.

Deep Learning-Based Nystagmus Detection for BPPV Diagnosis.

In this study, we propose a deep learning-based nystagmus detection algorithm using video oculography (VOG) data to diagnose benign paroxysmal positional vertigo (BPPV). Various deep learning architectures were utilized to develop and evaluate nystagmus detection models. Among the four deep learning architectures used in this study, the CNN1D model proposed as a nystagmus detection model demonstrated the best performance, exhibiting a sensitivity of 94.06 ± 0.78%, specificity of 86.39 ± 1.31%, precision of 91.34 ± 0.84%, accuracy of 91.02 ± 0.66%, and an F1-score of 92.68 ± 0.55%. These results indicate the high accuracy and generalizability of the proposed nystagmus diagnosis algorithm. In conclusion, this study validates the practicality of deep learning in diagnosing BPPV and offers avenues for numerous potential applications of deep learning in the medical diagnostic sector. The findings of this research underscore its importance in enhancing diagnostic accuracy and efficiency in healthcare.

Nystagmus and Foveal Hypoplasia in a Carrier of Oculocutaneous Albinism.

We report a 23-year-old female patient with ophthalmic features of albinism, including refractive errors, nystagmus, depigmented fundus, and foveal hypoplasia. She presented for a rhegmatogenous retinal detachment, which was surgically reattached with no complications. Further genetic testing revealed the presence of a heterozygous pathogenic oculocutaneous albinism OCA2 gene mutation, conferring carrier status. To the best of our knowledge, this is the first reported case of typical ocular phenotype of albinism, specifically nystagmus, in a patient who is carrier for oculo-cutaneous albinism. Further research is required to expand the genotype-phenotype relationship in carriers of oculocutaneous albinism. [Ophthalmic Surg Lasers Imaging Retina 2024;55:349-353.].

Long-term visual outcomes in spasmus nutans.

BACKGROUND: The long-term visual outcomes in spasmus nutans patients is largely unknown. The purpose of this study was to characterize visual outcomes and identify comorbid ophthalmic conditions in patients with spasmus nutans. METHODS: We retrospectively reviewed the charts of consecutive patients diagnosed with spasmus nutans between 2000 and 2020. Demographic information, ophthalmic characteristics, and neuroimaging results were assessed over time. RESULTS: Of the 32 patients included in the study, 13 (41%) were female. Underlying medical conditions included a diagnosis of Trisomy 21 in 6 (19%) and prematurity in 8 (25%). Twenty-one patients (66%) self-reported as a race other than Caucasian. 18 patients (56%) had non-private health insurance and 1 (3%) was uninsured. Mean age at diagnosis and resolution were 16 months (range 45 months) and 48 months (range 114 months), respectively. All 32 patients had nystagmus, 31 (97%) had head nodding and 16 (50%) had ocular torticollis. Mean follow-up was 66 months (range 185 months). On initial presentation, 6/32 (19%) had an amblyogenic refractive error and mean best-corrected visual acuity (BCVA) in the better-seeing eye was 0.78 Logarithm of the Minimum Angle of Resolution (LogMAR) (range 1.24). In a sub-analysis that included patients with > 1 exam (n = 23), 17/20 (85%) had an amblyogenic refractive error and mean BCVA in the better-seeing eye was 0.48 LogMAR (range 1.70). At the final exam, 12 patients had measurable stereopsis, eight had strabismus, and three had undergone strabismus surgery. Eight patients required treatment for amblyopia. CONCLUSIONS: We found a high prevalence of amblyogenic refractive error, strabismus and amblyopia among patients with spasmus nutans. Children with spasmus nutans benefit from ongoing ophthalmic follow-up until they are past the amblyopic age range, even after resolution of nystagmus.

Accuracy of the Bedside Examination in Patients With Suspected Acute Unilateral Peripheral Vestibulopathy.

OBJECTIVE: Acute unilateral peripheral vestibulopathy (AUPVP) is a frequent form of peripheral vestibular vertigo characterized by unilateral vestibular organ dysfunction. Diagnostic challenges in anamnesis and bedside examination can lead to potential misdiagnoses. This study investigated the sensitivity of bedside examinations in diagnosing AUPVP. METHODS: This retrospective analysis examined 136 AUPVP inpatients at a level 3 university hospital between 2017 and 2019. Demographic data and bedside test results were collected. Instrumental otoneurological tests included caloric testing and video head impulse test (HIT). The sensitivity of each bedside parameter was computed based on the instrumental diagnostics, and statistical analyses were performed. RESULTS: The study included 76 men and 60 women, with a mean age of 59.2 years. Spontaneous nystagmus exhibited a sensitivity of 92%, whereas the absence of skew deviation was identified with a sensitivity of 98%. Abnormal bedside HIT showed a sensitivity of 87%. The combined HINTS (HIT, nystagmus, and test of skew) had a sensitivity of 83%. The Romberg test and Fukuda test demonstrated sensitivities of 26% and 48%, respectively. CONCLUSION: The sensitivity of bedside tests varied from 26% to 98%. This aligns with previous literature, highlighting the challenge of differentiating AUPVP from vestibular pseudoneuritis solely through bedside examination. Although the tests excel in excluding central causes, they are insufficient for diagnosing AUPVP with certainty. In addition, the bedside examination sensitivities vary widely, and early radiological imaging can be misleading. Therefore, this study underlines the necessity of prompt otoneurological testing for accurate exclusion of vestibular pseudoneuritis and thus improve patient outcomes.

Use of the Head Impulse, Nystagmus, Test of Skew ('HINTS') assessment to aid differential diagnosis in acute vestibular syndrome in the hyperacute stroke setting.

BACKGROUND: Differential diagnosis of acute vertigo syndrome is challenging given the similarities between clinical presentations of posterior circulation stroke and peripheral vestibular dysfunction. The Head Impulse, Nystagmus, Test of Skew ('HINTS') assessment is a clinical bedside test used to aid diagnosis. METHODS: Comprehensive training on use of the Head Impulse, Nystagmus, Test of Skew assessment was provided to one stroke consultant, and the effectiveness of the test in that setting was assessed. Further education was completed with more members of the stroke and emergency department multi-disciplinary team. Quality improvement measures including magnetic resonance imaging use and bed utilisation were explored. RESULTS: Following training of one stroke consultant, the Head Impulse, Nystagmus, Test of Skew assessment was found to be a feasible, accurate bedside test within this acute stroke service. Further training for the multi-disciplinary team was completed, but outcome measures were not explored because of the coronavirus disease 2019 pandemic and maternity leave. CONCLUSION: There is a role for trained members of the multi-disciplinary team to successfully use the Head Impulse, Nystagmus, Test of Skew assessment in hyperacute stroke settings, to aid diagnosis in acute vertigo syndrome.

Advances in the diagnosis and management of acute vertigo.

BACKGROUND: Patients presenting to the emergency department with acute vertigo pose a diagnostic challenge. While 'benign' peripheral vestibulopathy is the most common cause, the possibility of a posterior circulation stroke is paradoxically the most feared and missed diagnosis in the emergency department. OBJECTIVES: This review will attempt to cover the significant advances in the ability to diagnose acute vertigo that have occurred in the last two decades. The review discusses the role of neurological examinations, imaging and specific oculomotor examinations. The review then discusses the relative attributes of the Head Impulse-Nystagmus-Test of Skew plus hearing ('HINTS+') examination, the timing, triggers and targeted bedside eye examinations ('TiTrATE'), the associated symptoms, timing and triggers, examination signs and testing ('ATTEST') algorithm, and the spontaneous nystagmus, direction, head impulse testing and standing ('STANDING') algorithm. The most recent technological advancements in video-oculography guided care are discussed, as well as other potential advances for clinicians to look out for.

Vertical infantile nystagmus: Explanation of why the direction of nystagmus is vertical.

This case report presents a rare case of infantile nystagmus syndrome (INS) in which the direction of infantile nystagmus (IN) was vertical. A 66-year-old woman was referred to our department for investigation of abnormal eye movements. She showed a disordered field of view with a homonymous hemianopia in the lower left quadrant and vertical gaze-evoked nystagmus, but there were no other abnormal neurological findings. She did not complain of an oscillopsia. Imaging revealed that the cause of hemianopia was atrophy and low cerebral blood flow in the right occipital lobe. The vertical nystagmus became strong when attempting to fixate to stationary targets. A reversed optokinetic nystagmus response was observed in the vertical optokinetic nystagmus test. From these eye movements, we diagnosed her nystagmus as vertical IN. Patients with INS see everything by saccades. IN consists of the alternate appearance of saccades and preceding slow eye movements. For these eye movements, a wide visual field is necessary. In this case, vertical IN was caused by the wider vertical than horizontal visual field resulting from homonymous hemianopia. Therefore, the direction of IN is horizontal in most patients with INS because their horizontal visual field is the widest field.

Ophthalmic features of Lamb-Shaffer syndrome: a case series.

Lamb-Shaffer syndrome (LSS) is a rare neurodevelopmental disorder, genetically diagnosed in fewer than 100 individuals worldwide. We present a case series of 6 pediatric patients with LSS and describe its ophthalmic manifestations. Strabismus was present in 5 patients, with exotropia being most common. All subjects had significant refractive errors; 5 had astigmatism of at least 2 D. All patients had optic nerve abnormalities, including pallor (4), hypoplasia (2), and anomalous appearance (1), with retinal nerve fiber layer thinning demonstrated in a single subject. Other ophthalmic disorders detected were ptosis (1), nasolacrimal duct obstruction (1), and nystagmus (2).

A new roll test to diagnose posterior semicircular canal benign paroxysmal positional vertigo.

BACKGROUND: The Dix-Hallpike (DH) test is a gold standard for diagnosing benign paroxysmal positional vertigo (BPPV). However, lateral semicircular canal BPPV is not rare. We have been performing the new roll test that begins from the sitting position and contains a head-hanging position, in order not to overlook lateral canal BPPV. We noticed that transient vertical/torsional nystagmus sometimes occurs during the new roll test. OBJECTIVE: To clarify the value of the new roll test in diagnosing posterior canal BPPV and elucidate the position that elicits nystagmus. MATERIALS AND METHODS: The subjects were 100 consecutive patients (79 were female, 21 were male) with posterior canal BPPV. We classified the patients into four types based on a position that induced nystagmus. RESULTS: The patient's position that elicited nystagmus varied. The supine type accounted for 24 %, the lateral type accounted for 62 %, the head-hanging type accounted for 9 %, and the DH type accounted for 5 %. CONCLUSION: The new roll test is valuable for diagnosing posterior canalolithiasis cases. Most patients reveal vertical/torsional nystagmus in the supine or lateral position. Therefore, performing the new roll test first is efficient at the initial visit.

De novo FRMD5 Missense Variants in Patients with Childhood-Onset Ataxia, Prominent Nystagmus, and Seizures.

BACKGROUND: FRMD5 variants were recently identified in patients with developmental delay, ataxia, and eye movement abnormalities. OBJECTIVES: We describe 2 patients presenting with childhood-onset ataxia, nystagmus, and seizures carrying pathogenic de novo FRMD5 variants. Weighted gene co-expression network analysis (WGCNA) was performed to gain insights into the function of FRMD5 in the brain. METHODS: Trio-based whole-exome sequencing was performed in both patients, and CoExp web tool was used to conduct WGCNA. RESULTS: Both patients presented with developmental delay, childhood-onset ataxia, nystagmus, and seizures. Previously unreported findings were diffuse choreoathetosis and dystonia of the hands (patient 1) and areas of abnormal magnetic resonance imaging signal in the white matter (patient 2). WGCNA showed that FRMD5 belongs to gene networks involved in neurodevelopment and oligodendrocyte function. CONCLUSIONS: We expanded the phenotype of FRMD5-related disease and shed light on its role in brain function and development. We recommend including FRMD5 in the genetic workup of childhood-onset ataxia and nystagmus. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

ERG Responses in Albinism, Idiopathic Infantile Nystagmus, and Controls.

Purpose: Our primary aim was to compare adult full-field ERG (ffERG) responses in albinism, idiopathic infantile nystagmus (IIN), and controls. A secondary aim was to investigate the effect of within-subject changes in nystagmus eye movements on ffERG responses. Methods: Dilated Ganzfeld flash ffERG responses were recorded using DTL electrodes under conditions of dark (standard and dim flash) and light adaptation in 68 participants with albinism, 43 with IIN, and 24 controls. For the primary aim, the effect of group and age on ffERG responses was investigated. For the secondary aim, null region characteristics were determined using eye movements recorded prior to ffERG recordings. ffERG responses were recorded near and away from the null regions of 18 participants also measuring the success rate of recordings. Results: For the primary aim, age-adjusted photopic a- and b-wave amplitudes were consistently smaller in IIN compared with controls (P < 0.0001), with responses in both groups decreasing with age. In contrast, photopic a-wave amplitudes increased with age in albinism (P = 0.0035). For the secondary aim, more intense nystagmus significantly reduced the success rate of measurable responses. Within-subject changes in nystagmus intensity generated small, borderline significant differences in photopic b-wave peak times and a-and b-wave amplitudes under scotopic conditions with standard flash. Conclusions: Age-adjusted photopic ffERG responses are significantly reduced in IIN adding to the growing body of evidence of retinal abnormalities in IIN. Differences between photopic responses in albinism and controls depend on age. Success at obtaining ffERG responses could be improved by recording responses at the null region.

[Discussion and analysis the value of supine median³ nystagmus in the diagnosis and treatment of HC-BPPV].

Objective:To explore the clinical value of supine median³ nystagmus in the accurate diagnosis of horizontal semicircular canal benign paroxysmal positional vertigo（HC-BPPV）. Methods:A total of 187 patients with HC-BPPV admitted to the First Affiliated Hospital of Xi'an Jiaotong University from June 2020 to March 2021 were selected. Among them 42 cases of Cupulolithiasis and 145 cases of Canalithiasis. The nystagmus parameters of patients left and right supine position and supine median³ position were recorded in detail by RART. According to the direction of supine median³ nystagmus, patients were divided into three groups: group A（nystagmus to weak side）, group B（nystagmus to strong side）, group C（negative nystagmus）. The canalith repositioning manoeuvres（CRM） was carried out by utility of an automatic vestibular function diagnosis and therapy system（SRM-IV）. The cure rate of CRM in three groups of HC-BPPV patients was compared, Multivariate logistic regression analysis was performed to analyze the influencing factors of CRM for HC-BPPV. Results:The cure rates of group A, group B and group C were 81.58%, 16.13% and 56.25%, respectively. The difference among the three groups was statistically significant. Then a pairwise comparison of group A, B and C, the difference was statistically significant（χ²A-B=40.294,P<0.001,χ²B-C=14.528, P<0.001,χ²A-C=11.606, P=0.001）; the results of multivariate logistic regression analysis showed that the direction of supine median³ nystagmus and BMI were the influencing factors of CRM for HC-BPPV. Conclusion:The direction, intensity and duration of supine median³ nystagmus play an important role in determining the responsibility semicircular canal of HC-BPPV.