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BACKGROUND: There are ≈5 million annual dizziness visits to US emergency departments, of which vestibular strokes account for over 250 000. The head impulse, nystagmus, and test of skew eye examination can accurately distinguish vestibular strokes from peripheral dizziness. However, the eye-movement signs are subtle, and lack of familiarity and difficulty with recognition of abnormal eye movements are significant barriers to widespread emergency department use. To break this barrier, we sought to assess the accuracy of EyePhone, our smartphone eye-tracking application, for quantifying nystagmus. METHODS AND RESULTS: We prospectively enrolled healthy volunteers and recorded the velocity of induced nystagmus using a smartphone eye-tracking application (EyePhone) and then compared the results with video oculography (VOG). Following a calibration protocol, the participants viewed optokinetic stimuli with incremental velocities (2-12 degrees/s) in 4 directions. We extracted slow phase velocities from EyePhone data in each direction and compared them with the corresponding slow phase velocities obtained by the VOG. Furthermore, we calculated the area under the receiver operating characteristic curve for nystagmus detection by EyePhone. We enrolled 10 volunteers (90% men) with an average age of 30.2±6 years. EyePhone-recorded slow phase velocities highly correlated with the VOG recordings (r=0.98 for horizontal and r=0.94 for vertical). The calibration significantly increased the slope of linear regression for horizontal and vertical slow phase velocities. Evaluating the EyePhones performance using VOG data with a 2 degrees/s threshold showed an area under the receiver operating characteristic curve of 0.87 for horizontal and vertical nystagmus detection. CONCLUSIONS: We demonstrated that EyePhone could accurately detect and quantify optokinetic nystagmus, similar to the VOG goggles.

Objectives: The Epley maneuver (EM) shows immediate effect, wherein disappearance of positional nystagmus occurs soon after the EM. Our previous study showed that setting interval times during the EM reduced the immediate effect. The purpose of this study is to identify the head position for which interval time reduces the immediate effect. Methods: Fifty-one patients with posterior canal type of benign paroxysmal positional vertigo (BPPV) were randomly assigned to the following three groups: 10 min interval time set at the first head position of the EM in group A, at the third head position in group B, and at the fourth head position in group C. The primary outcome measure (POＭ) was the ratio of maximum slow-phase eye velocity of positional nystagmus soon after the EM, compared with that measured before the EM. A large ratio value indicates a poor immediate effect of the EM. Results: The POＭ in group A (0.07) was smallest (B: 0.36, C: 0.49) (p < 0.001). Discussion: The interval times at the third and fourth head positions reduced the immediate effect of the EM. Our previous study showed that the effect of BPPV fatigue is continued by maintaining the first head position of the EM. BPPV fatigue constitutes fatigability of positional nystagmus with repeated performance of the Dix-Hallpike test. Our findings may be interpreted in accordance with the theory that the immediate effect of the EM is BPPV fatigue itself, because we observed that the effect of BPPV fatigue is strongest in group A. [ABSTRACT FROM AUTHOR]

Purpose: This study introduces and evaluates the sitting lateral canal maneuver (SLCM), a novel seated repositioning technique for treating geotropic lateral canal benign paroxysmal positional vertigo (BPPV). Methods: We conducted a retrospective chart review at the Hospital of Salerno, focusing on 26 patients diagnosed with geotropic LC-BPPV between 2021 and 2022. The SLCM was applied, and its efficacy was assessed based on the resolution of nystagmus and vertigo symptoms. A 95% confidence interval was calculated to estimate the success rate. Results: The SLCM demonstrated a high success rate, with 22 out of 26 patients (approximately 85%, 22/26 patients) showing positive outcomes. The 95% confidence interval for the success rate ranged from approximately 65.02–100%. These findings suggest that SLCM is a potentially effective intervention for LC-BPPV, especially beneficial for patients who find traditional supine or lateral maneuvers uncomfortable. Conclusion: The SLCM represents a promising alternative to traditional BPPV maneuvers, especially for patients requiring a seated approach. While the initial results are encouraging, further research with larger sample sizes and longer follow-up periods is needed to validate its efficacy and explore its full potential in the management of LC-BPPV. Level of evidence: This study represents a Level IV source of evidence, as defined by the evidence-based practice guidelines. It is a retrospective chart review that involves a moderate cohort of patients diagnosed with geotropic horizontal positional nystagmus consistent with lateral canal benign paroxysmal positional vertigo (LC-BPPV). While the study provides valuable insights into the efficacy of the sitting lateral canal maneuver (SLCM) and contributes to the existing literature on BPPV management, it is important to note the inherent limitations associated with this level of evidence. [ABSTRACT FROM AUTHOR]

Introduction: Benign positional paroxysmal vertigo (BPPV) stands as the commonest cause for vertigo. It accounts for 20% of all cases of vertigo, even with its high prevalence rate it often goes underdiagnosed and undertreated. Development of the consensus document by the Bárány society's International Classification of Vestibular Disorders (ICVD)significantly facilitates the diagnosis of BPPV and its variants. This study assesses the utilisation of ICVD criteria for managing BPPV. Methodology: This is a cross-sectional descriptive study conducted at a tertiary care hospital in Northern India spanning from November 1, 2022, to November 30, 2023. A total of 110 participants diagnosed with BPPV were enrolled consecutively. All participants underwent Dix-Hallpike and supine log roll positional maneuvers. Diagnosis was made based on the history and type of nystagmus seen, and classified as per the ICVD criteria. Results: Posterior semicircular canalolithiasis (pc-BPPV) accounted for 25.45% of cases and horizontal canal canalolithiasis (hc-BPPV) accounted for 20.91% of cases. Probable BPPV, spontaneously resolved (pBPPVsr) was diagnosed in 16.36% of participants and possible BPPV(pBPPV) was diagnosed in 18.18% of participants. Multiple canal BPPV (mc-BPPV) accounted for 17.27% of cases. One participant was diagnosed with horizontal canal cupulolithiasis and anterior canal canalolithiasis respectively. No participant was diagnosed with posterior canal cupulolithiasis. Conclusion: The most common type of BPPV was pc-BPPV followed by hc-BPPV. The affected canal in possible BPPV, can be identified, and appropriate repositioning maneuvers are effective in treating them as well as aids in confirming the diagnosis. The diagnostic clarity provided by ICVD, aids in effective management of BPPV. More studies with larger sample size are required to further validate its clinical utility. [ABSTRACT FROM AUTHOR]

In the first days after a spaceflight (SF), re-entry motion sickness and motor coordination problems reflect the need to readapt back to the natural gravitational state. Gravity is a natural stimulus for the receptors of vestibular apparatus, which plays an important role in multisensory interactions. Changes indicating an increase in excitability of the vestibular apparatus during SF (Kornilova et al., 2017) suggest a high probability of the occurrence of gaze-evoked nystagmus after prolonged SF. Russian-American experiment "Field Test" included a nystagmus test. 22 ISS crewmembers (14 Russian cosmonauts and 8 astronauts; flight duration 159.8 ± 19.5 days) participated in the experiment. The study was conducted twice before flight and several times after flight, starting within 3 h after landing. In a seated position, astronauts tracked with their eyes only (without moving their head) horizontal and vertical movements of the researcher's finger from the central position to the gaze end points (right, left, upper). Eye movements were recorded with a video camera. The videos were analyzed qualitatively for presence of nystagmus. Preflight, gaze-evoked nystagmus was detected in 5 people, the greatest changes were observed on landing day. 10 crewmembers exhibited nystagmus in the extreme left gaze position and 13 crewmembers – in the extreme right gaze position (partial recovery was observed 1–4 days after SF). A noticeable decrease in the frequency of manifestation of the nystagmus was observed only 10–13 days after landing (n = 16). Gaze-evoked nystagmus is usually considered a clinical sign of cerebellar alterations. However, it is often described in healthy people with a prevalence of up to 21 %. In a similar study involving 18 astronauts, participants of long-term SF, the frequency of occurrence of gaze-evoked nystagmus also increased in the first hours after SF (Reschke, Good and Clement, 2017). However, in this study, a detailed analysis of the presence of nystagmus in various directions was conducted for the first time. Of particular interest is the frequent detection of a gaze-evoked nystagmus in the right position after SF - this phenomenon may be a sign of presence of a central vestibular imbalance (Robinson et al., 1984), which also occurs in patients with cerebellar disorders (Bayer and Dietrich, 2011). The results allow us to expand our understanding of the severity and frequency of vestibular disorders and the dynamics of their recovery after prolonged SF. • The results of the Russian-American space experiment "Field Test". • Most often, gaze-evoked nystagmus occurs in the extreme right position of the gaze. • Within the first 3 h after landing the most pronounced changes were observed. [ABSTRACT FROM AUTHOR]

Introduction: In patients with unilateral loss of vestibular function (UVL) vibration of the skull leads to a response of the vestibulo-ocular reflex (VOR) called vibration-induced nystagmus (VIN), with slow phases usually directed toward the paretic ear. This response is thought to result from the difference between the neural discharge in semicircular canal afferents from the healthy and the affected labyrinth. The brain interprets this difference as a sustained imbalance in angular (rotational) vestibular tone, which in natural circumstances would only occur when the head was rotating at a constant acceleration. Methods: To study this effect, we used a contemporary model of the neural network that combines sensory information about head rotation, translation, and tilt relative to gravity to estimate head orientation and motion. Based on the model we hypothesize that in patients with UVL, the brain may estimate not only a "virtual" rotation from the induced canal imbalance but also a subsequent "virtual" translation from the incorrect computation of the orientation of the head relative to gravity. If this is the case, the pattern of vibration-induced nystagmus will depend on the orientation of the head relative to gravity during the stimulation. This model predicts that this "virtual" translation will alter the baseline VIN elicited with the head upright; augmenting it when the affected ear is down and diminishing it when the affected ear is up. Results: Confirming this hypothesis, we recorded VIN in 3 patients with UVL (due to vestibular neuritis) in upright, right ear-down, and left ear-down positions and each showed the expected pattern. Discussion: From a practical, clinical view, our results and modeling suggest that positional VIN might reveal a hidden imbalance in angular vestibular tone in patients with UVL, when patients have equivocal signs of a vestibular imbalance, such as a minute amount of spontaneous or vibration-induced nystagmus with the head upright. This research provides insights into the underlying mechanisms of vestibular processing, the analysis of nystagmus in patients with UVL, and guides the design of a new bedside diagnostic test to assess vestibular function in patients with dizziness and imbalance. [ABSTRACT FROM AUTHOR]

Downbeat nystagmus (DBN) is the most common form of acquired central vestibular nystagmus. Gravity perception in patients with DBN has previously been investigated by means of subjective visual straight ahead (SVA) and subjective visual vertical (SVV) in the pitch and roll planes only during whole-body tilts. To our knowledge, the effect of head tilt in the roll plane on the SVV and on DBN has not yet been systematically studied in patients. In this study, we investigated static and dynamic graviceptive function in the roll-plane in patients with DBN (patients) and healthy-controls (controls) by assessment of the Subjective Visual Vertical (SVV) and the modulation of slow-phase-velocity (SPV) of DBN. SPV of DBN and SVV were tested at different head-on trunk-tilt positions in the roll-plane (0°,30° clockwise (cw) and 30° counterclockwise (ccw)) in 26 patients suffering from DBN and 13 controls. In patients, SPV of DBN did not show significant modulations at different head-tilt angles in the roll-plane. SVV ratings did not differ significantly between DBN patients vs. controls, however patients with DBN exhibited a higher variability in mean SVV estimates than controls. Our results show that the DBN does not exhibit any modulation in the roll-plane, in contrast to the pitch-plane. Furthermore, patients with DBN show a higher uncertainty in the perception of verticality in the roll-plane in form of a higher variability of responses. [ABSTRACT FROM AUTHOR]

Paroxysmal positional nystagmus frequently occurs in lesions involving the cerebellum, and has been ascribed to disinhibition and enhanced canal signals during positioning due to cerebellar dysfunction. This study aims to elucidate the mechanism of central positional nystagmus (CPN) by determining the effects of baclofen on the intensity of paroxysmal positional downbeat nystagmus due to central lesions. Fifteen patients with paroxysmal downbeat CPN were subjected to manual straight head-hanging before administration of baclofen, while taking baclofen 30 mg per day for at least one week, and two weeks after discontinuation of baclofen. The maximum slow phase velocity (SPV) and time constant (TC) of the induced paroxysmal downbeat CPN were analyzed. The positional vertigo was evaluated using an 11-point numerical rating scale (0 to 10) in 9 patients. After treatment with baclofen, the median of the maximum SPV of paroxysmal downbeat CPN decreased from 30.1°/s [interquartile range (IQR) = 19.6—39.0°/s] to 15.2°/s (IQR = 11.2—22.0°/s, Wilcoxon signed rank test, p < 0.001) with the median decrement ratio at 40.2% (IQR = 28.2—50.6%). After discontinuation of baclofen, the maximum SPV re-increased to 24.6°/s (IQR = 13.1—34.4°/s, Wilcoxon signed rank test, p = 0.001) with the median increment ratio at 23.5% (IQR = 5.2—87.9%). In contrast, the TCs of paroxysmal downbeat CPN remained unchanged at approximately 3.0 s throughout the evaluation. The positional vertigo also decreased with the medication (Wilcoxon signed rank test, p = 0.020), and remained unchanged even after discontinuation of medication (Wilcoxon signed rank test, p = 0.737). The results of this study support the prior presumption that paroxysmal CPN is caused by enhanced responses of the semicircular canals during positioning due to cerebellar disinhibition. Baclofen may be tried in symptomatic patients with paroxysmal CPN. [ABSTRACT FROM AUTHOR]

Benign paroxysmal positional vertigo (BPPV) is a common vestibular disorder characterized by brief episodes of vertigo triggered by changes in head position. Epley's manoeuvre and Semont's manoeuvre are widely used canalith repositioning procedures for the treatment of BPPV. This study aimed to compare the effectiveness of these two manoeuvres in treating post-canal BPPV in a cohort of 100 patients. Methods: This was a prospective, comparative study conducted at a tertiary care hospital. One hundred patients diagnosed with post-canal BPPV were randomized into two groups: Group A (n = 50) underwent the Epley's manoeuvre, and Group B (n = 50) underwent the Semont's manoeuvre. The patients were assessed for the resolution of vertigo and nystagmus immediately after the manoeuvre and at a follow-up visit one week later. The resolution of symptoms was confirmed through Dix-Hallpike test. Results: In Group A, 46 patients (92%) reported complete resolution of vertigo immediately after Epley's manoeuvre, and 47 patients (94%) had no nystagmus on the Dix-Hallpike test at the one-week follow-up. In Group B, 42 patients (84%) reported complete resolution of vertigo immediately after Semont's manoeuvre, and 44 patients (88%) had no nystagmus on the DH test at the one-week follow-up. The difference in effectiveness between the two manoeuvres was not statistically significant (p > 0.05). Conclusion: Both Epley's manoeuvre and Semont's manoeuvre are effective in treating post-canal BPPV, with similar success rates. The choice of manoeuvre may depend on patient preference, clinician expertise, and other individual factors. Further studies with larger sample sizes are warranted to validate these findings and explore other potential factors influencing the outcomes of canalith repositioning manoeuvres in BPPV. [ABSTRACT FROM AUTHOR]

Pelizaeus-Merzbacher-like disease (PMLD, OMIM #608804) is an autosomal recessive hypomyelinating leukodystrophy caused by homozygous variants in the GJC2 gene. It usually presents in the first months of life with nystagmus, developmental delay, and diffuse hypomyelination on brain magnetic resonance imaging (MRI). We report a case of a 3-year-old boy that presented with nystagmus and global developmental delay. MRI showed diffuse hypomyelination, including the cerebellum. Pelizaeus-Merzbacher disease (PMD) was suspected; however, no pathological variants of the PLP1 gene were found. Exome sequencing found variants in the GJC2 gene, leading to a diagnosis of PMLD. The combination of global developmental delay, hypomyelination, and nystagmus in a child should raise suspicion of PMD and PMLD. Unlike PMD, however, hypomyelination of the brainstem and cerebellum are frequently seen and brainstem auditory evoked potentials are usually normal in PMLD. The latter has an overall better prognosis than the former as well. Epidemiological studies on leukodystrophies have found conflicting results on which disease is more common. However, PMLD is a rare leukodystrophy and both PMLD and PMD should be considered in any child with developmental delay, hypomyelination, and nystagmus. [ABSTRACT FROM AUTHOR]

Background and Objectives: This study reviews the current literature on ocular movements, specifically focusing on nystagmus associated with peripheral vestibular disorders, to enhance diagnostic accuracy. The evaluation of ocular movements, particularly nystagmus, provides essential insights into the function and dysfunction of the vestibular system, helping clinicians distinguish between peripheral and central causes of vertigo and imbalance. Materials and Methods: A comprehensive search of PubMed was conducted using key terms such as "ocular movements", "nystagmus", "vestibular nystagmus", and "peripheral vestibular disorders". Results: The search yielded 2739 titles, and after a rigorous selection process, 52 articles were reviewed in full. Discussion: The review highlights different classifications and types of nystagmus, including physiological and pathological forms, and their diagnostic relevance in vestibular disorders such as benign paroxysmal positional vertigo (BPPV), vestibular neuritis, and Meniere's disease. Diagnostic techniques like video/electro-oculography are emphasized for their role in assessing vestibular function and identifying abnormalities. The study underscores the importance of detailed ocular examination in the diagnosis of peripheral vestibular disorders and proposes an algorithm to aid this process. Conclusions: While not a systematic review, this study highlights the importance of detailed ocular examination in diagnosing peripheral vestibular disorders and presents an algorithm to facilitate this process. It also emphasizes the need for continued research and advancements in vestibular medicine to further understand ocular movements and their clinical significance, ultimately contributing to improved patient outcomes. [ABSTRACT FROM AUTHOR]

This paper presents the anatomical and biomechanical aspects of chronic instability of the craniocervical junction (CCJ) with a discussion on clinical diagnostics based on mobility tests and provocative tests related to ligamentous system injuries, as well as radiological criteria for CCJ instability. In addition to the structural instability of the CCJ, the hypothesis of its functional form resulting from cervical proprioceptive system (CPS) damage is discussed. Clinical and neurophysiological studies have shown that functional disorders or organic changes in the CPS cause symptoms similar to those of vestibular system diseases: dizziness, nystagmus, and balance disorders. The underlying cause of the functional form of CCJ instability may be the increased activity of mechanoreceptors, leading to "informational noise" which causes vestibular system disorientation. Due to the disharmony of mutual stimulation and the inhibition of impulses between the centers controlling eye movements, the cerebellum, spinal motoneurons, and the vestibular system, inadequate vestibulospinal and vestibulo-ocular reactions occur, manifesting as postural instability, dizziness, and nystagmus. The hyperactivity of craniocervical mechanoreceptors also leads to disturbances in the reflex regulation of postural muscle tone, manifesting as "general instability". Understanding this form of CCJ instability as a distinct clinical entity is important both diagnostically and therapeutically as it requires different management strategies compared to true instability. Chronic CCJ instability significantly impacts the quality of life (QOL) of affected patients, contributing to chronic pain, psychological distress, and functional impairments. Addressing both structural and functional instability is essential for improving patient outcomes and enhancing their overall QOL. [ABSTRACT FROM AUTHOR]

Background: Children with visual impairment often exhibit poor postural control. However, the effects of strabismus on oculomotor system components and its impact on balance in children are not yet fully understood. This study aims to determine the potential effects of oculomotor functions on balance skills in children with strabismus. Methods: A total of 30 children aged between 6 and 10 years participated in this study. Fifteen children diagnosed with strabismus were included in the strabismus group (8.07 ± 1.33 years), and 15 healthy children without any vision problems were included in the control group (8.03 ± 1.49 years). All children underwent a comprehensive hearing evaluation, bedside neurological and balance examinations, the Pediatric Balance Scale (PBS) assessment to assess balance function, and Videonystagmography (VNG) tests to measure oculomotor function. Results: In the saccade test, no significant differences were found between the groups in terms of latency, accuracy, and speed (p > 0.05). The strabismus group showed significantly lower pursuit test gains (except the left eye at 0.4 Hz) (p < 0.05) and significantly higher asymmetries (except the right eye at 0.4 Hz) (p < 0.05). No significant difference was observed between the groups in optokinetic test gains (p > 0.05). The strabismus group had significantly lower scores on the 360-degree rotation task (10th item) (p = 0.027) and total PBS scores (p = 0.029). Correlation analysis revealed statistically significant negative correlations between strabismus angle and optokinetic test gains, pursuit test gains, and PBS total scores, with varying correlation strengths (p < 0.05 and − 0.639 < r < − 0.338). Conclusions: Strabismus adversely affects the optokinetic and pursuit systems, as well as balance in children. Furthermore, an increase in the strabismus angle is associated with greater adverse effects on these functions. The lower scores obtained in the PBS scores of the strabismus group indicate that strabismus may negatively affect balance skills in activities of daily living. Early intervention and targeted therapies should be considered to mitigate these effects and support the development of balance skills in children with strabismus. [ABSTRACT FROM AUTHOR]

Aim: A clinical study was performed to test the usability of a smartphone eyescanning app at a needle exchange facility to detect drug use to support therapy. Methods: The study recruited 24 subjects who visited the facility one to three times, making a total of 40 visits. During each visit the subjects underwent testing for non-convergence (NC), nystagmus (NY), and pupillary light reflex (PLR) using a smartphone-based eHealth system. The collected eye data were transformed into key features that represent eye characteristics. During each visit, a time-line follow-back interview on recent drug use and a usability questionnaire were completed. Results: Technical usability of the smartphone eye-scanning app was good for PLR and NC, where key features were generated in 82%-91% of the cases. For NY, only 60% succeeded due to cognitive problems to follow instructions. In most cases, subjects were under the influence of drugs when participating in the tests, with an average of 2.4 different drugs ingested within the last 24 h. The key features from PLR could distinguish use of opioids from central stimulants. The usability questionnaire results indicate that 23 of the 24 subjects could perform the eye-scanning by themselves after a short training, even when under severe influence of drugs. The caregiver assessed that 20 out of the 24 challenging subjects could potentially perform these tests in an indoors, home-like environment. Conclusions: Smartphone-based eye-scanning is functional in a patient population with heavy drug use, also when under the influence of drugs. The use of central stimulants can be distinguished from the use of opioids. [ABSTRACT FROM AUTHOR]

Repeat expansions in FGF14 cause autosomal dominant late-onset cerebellar ataxia (SCA27B) with estimated pathogenic thresholds of 250 (incomplete penetrance) and 300 AAG repeats (full penetrance), but the sequence of pathogenic and non-pathogenic expansions remains unexplored. Here, we demonstrate that STRling and ExpansionHunter accurately detect FGF14 expansions from short-read genome data using outlier approaches. By combining long-range PCR and nanopore sequencing in 169 patients with cerebellar ataxia and 802 controls, we compare FGF14 expansion alleles, including interruptions and flanking regions. Uninterrupted AAG expansions are significantly enriched in patients with ataxia from a lower threshold (180–200 repeats) than previously reported based on expansion size alone. Conversely, AAGGAG hexameric expansions are equally frequent in patients and controls. Distinct 5' flanking regions, interruptions and pre-repeat sequences correlate with repeat size. Furthermore, pure AAG (pathogenic) and AAGGAG (non-pathogenic) repeats form different secondary structures. Regardless of expansion size, SCA27B is a recognizable clinical entity characterized by frequent episodic ataxia and downbeat nystagmus, similar to the presentation observed in a family with a previously unreported nonsense variant (SCA27A). Overall, this study suggests that SCA27B is a major overlooked cause of adult-onset ataxia, accounting for 23–31% of unsolved patients. We strongly recommend re-evaluating pathogenic thresholds and integrating expansion sequencing into the molecular diagnostic process. Repeat expansions in the FGF14 gene can cause late-onset cerebellar ataxia (SCA27B), however the defining features of pathogenic expansions remain uncertain. Here, the authors compare the sequence and structure of FGF14 repeat expansions in patients and controls, leading them to suggest a lower pathogenic threshold and emphasizing the importance of sequencing the full expansion for accurate interpretation. [ABSTRACT FROM AUTHOR]

Introduction. Posterior fossa tumours (PFTs) frequently present with ophthalmic complaints. The literature is mainly focused on PFTs affecting the pediatric age group, and the post-treatment visual outcomes (VOs) are scarcely reported. Objective. To evaluate the VOs at 6 months following the index surgery in patients with PFTs. Materials and methods. This retrospective study involved 50 patients of all age groups who underwent surgical resection of PFTs in the Department of Neurosurgery. The patients with PFTs, except those with low-grade tumours, received concurrent chemo-radiotherapy. Pre- and postoperative (6 months after the index surgery) ophthalmic examinations were done and compared. VOs included colour vision, night vision, visual acuity (VA), pupillary function (size, reactivity), papilledema grade, splinter haemorrhage, retinal venous dilatation, strabismus (esotropia and hypertropia), and nystagmus. Results. The patients were mainly aged 1-10 years (22%) with slight female predominance (52%). The most common PFTs were brainstem glioma and pilocytic astrocytoma (each 18%). At 6 months, there was no significant change in colour and night vision, pupil size and reactivity, splinter haemorrhage, and hypertropia (all pvalues> 0.05). A significantly lesser proportion of patients had moderate VA (pvalue= 0.013), retinal venous dilatation (p-value=0.001), and grade 1 (p-value=0.005) as well as grade 4 papilledema (p-value=0.041). Moreover, a significantly greater proportion of patients had grade 0 papilledema (p-value<0.0001). While the incidence of nystagmus and esotropia increased significantly (both p-values<0.0001). Conclusion. At 6 months, the majority of the patients had good VOs, including significant improvement in moderate VA, papilledema, and retinal venous dilatation. While nystagmus and esotropia increased significantly. [ABSTRACT FROM AUTHOR]

The present study was carried out at Madras Veterinary College Teaching Hospital on dogs (n=28) presented with head tilt, nystagmus, and strabismus, suggestive of vestibular disease. The standard neurologic examination was performed, which consisted of an evaluation of mental status (level of consciousness), gait and body posture, postural reactions, and cranial nerve examination. These animals underwent various diagnostic tests and were classified as peripheral vestibular disease (PVD, n=14) and central vestibular disease (CVD, n=14). Seventeen dogs (60.1%) out of 28 dogs irrespective of the group showed gait abnormalities such as veering or leaning, falling, circling, non-ambulatory tetra paresis, hypermetria, and wide-based stance. Among those dogs ambulatory tetra paresis was seen more with CVD dogs and leaning/veering was observed more in PVD dogs. Six dogs out of 28 dogs showed cranial nerve dysfunction irrespective of PVD or CVD with cranial V and IX dysfunction in CVD dogs. Spontaneous resting nystagmus was observed in 21 dogs out of 28 dogs while a higher percentage of horizontal nystagmus was observed in PVD dogs and vertical nystagmus was observed in CVD dogs. There were no significant differences between groups regarding prevalences of abnormalities of segmental spinal reflexes, spinal hyperpathia, alterations in muscle tone, muscle atrophy, and alterations in the cutaneous trunci reflex. Results of the present study suggested that the neurologic examination, in its entirety, allowed reliable localization of peripheral versus central neurologic dysfunction across interpreters, but no individual feature of the neurological examination bore a strong relationship to the location of the lesion. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of botulinum toxin A injection on the frequency of horizontal nystagmus in children. Methods: This was a non-randomized before-and-after clinical trial evaluating a cohort of children with horizontal nystagmus before and after treatment with botulinum toxin A. The toxin was injected under general anesthesia with spontaneous ventilation without intubation using the Mendonça forceps and the effect was evaluated by analyzing the frequency of the oscillation in Hertz (Hz) on video registrations before and after treatment. Results: The current study found a statistically significant difference on the frequency of the nystagmus in children before and after the injection of botulinum toxin A, with the mean frequency decreasing from 1.55 ± 0.94 Hz before treatment to 1.04 ± 0.87 Hz at 1 month post-injection (P <.001) and to 1.27 ± 0.87 Hz at 6 months post-injection (P =.002). When comparing the data 1 and 6 months post-injection, this study found a significant increase (P =.001) in the frequency of the nystagmus. Conclusions: The injection of botulinum toxin A is effective in reducing the frequency of oscillations in children with horizontal nystagmus both 1 and 6 months after the procedure, and can be used as a first-line, less invasive treatment aiming to decrease the frequency of oscillation. [J Pediatr Ophthalmol Strabismus. 2024;61(5):365–370.] [ABSTRACT FROM AUTHOR]

AIM: To investigate the effect of using base-out prisms on nystagmus, visual acuity and contrast sensitivity in patients with albinism. METHODS: In this interventional study, patients with albinism who had nystagmus were enrolled. A comprehensive eye exam was conducted, which included refraction, assessment of far and near vision acuity, and contrast sensitivity measurements. To check for the nystagmus, a videonystagmography was used. The tests were carried out in three modes: without any correction, with optical correction, and with correction using base-out prisms in three different powers, including 4, 6, and 8 prism diopters. RESULTS: Totally 23 patients with average age of 28.65±12.13 were examined. It was found that the use of optical correction and optical correction with prisms resulted in a statistically significant improvement in both far (at least: P

Abstract Background Oculocutaneous albinism (OCA) is a genetically heterogeneous condition that is associated with reduced or absent melanin pigment in the skin, hair, and eyes, resulting in reduced vision, high sensitivity to light, and rapid and uncontrolled eye movements. To date, seventeen genes have been associated with OCA including syndromic and non-syndromic forms of the condition. Methods Whole exome sequencing (WES) was performed to identify pathogenic variants in nine Pakistani families with OCA, with validation and segregation of candidate variants performed using Sanger sequencing. Furthermore, the pathogenicity of the identified variants was assessed using various in-silico tools and 3D protein structural analysis software. Results WES identified biallelic variants in three genes explaining the OCA in these families, including four variants in TYR, three in OCA2, and two in HPS1, including two novel variants c.667C > T: p.(Gln223*) in TYR, and c.2009 T > C: p.(Leu670Pro) in HPS1. Conclusions Overall, this study adds further knowledge of the genetic basis of OCA in Pakistani communities and facilitates improved management and counselling services for families suffering from severe genetic diseases in Pakistan.

Abstract 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.

Oculopalatal tremor (OPT) is a complex neurological disorder characterized by acquired oscillatory nystagmus synchronized with tremors of the soft palate and other muscles. The article discusses the pathology, clinical manifestations, and diagnostic methods of OPT. A comprehensive literature search was conducted in PubMed and Google Scholar using keywords and relevant articles were studied and analysis was done. Vertical pendular nystagmus is the hallmark, while other muscles such as the neck, head, larynx, and diaphragm may be affected. The pathophysiology is due to lesions of the Guillain–Mollaret triangle (GMT), which causes hypertrophy of the inferior olivary. Neuroimaging reveals hypertrophy of the inferior olivary medulla, which aids in diagnosis. Drug treatments such as gabapentin and memantine can reduce nystagmus, although the visual quality may not permanently improve. The study explores the complexity of the pathophysiology and clinical presentation of OPT. New treatments that target abnormal neuronal connections with drugs such as quinine or mefloquine are being investigated. The potential of deep brain stimulation (DBS) remains uncertain, with promising aspects but limited efficacy. A synergy of technology and treatment is proposed to advance OPT treatment. Future studies will aim to clarify the nuances of responses to OPT and may include a comparative study of medication and DBS. OPT is mainly caused by a disruption in GMT/dentato-rubro-olivary pathway, presenting with tremor, and nystagmus is diagnosed with magnetic resonance imaging. Gabapentin and memantine have proved to be effective in improving the condition except for visual changes.

Purpose: To evaluate the effect of topical carbonic anhydrase inhibitor (brinzolamide) versus placebo on visual function and waveforms in infantile nystagmus syndrome (INS). Design: Prospective, placebo-controlled, double-blind, cross-over study. Methods: Setting- A tertiary eye care center. Patients- Cases of idiopathic INS with and without abnormal head posture aged ≥10 years who had not received previous treatment for nystagmus. Intervention- Patients were randomized into two groups. Group 1 was given placebo for 3 months, and after a washout period of 7 days started on topical brinzolamide for the next 3 months. In group 2, the order was reversed. The drops were administered topically three times (every 8 hours) in both eyes. Outcome measure- Binocular best corrected visual acuity (BCVA) using the ETDRS chart, eXpanded nystagmus acuity function (NAFX) score and INS waveforms obtained from eye movement recordings, intraocular pressure (IOP) by Goldmann applanation tonometer, near stereopsis by TNO stereo test, and change in abnormal head posture before and after intervention in the null position. Results: A total of 29 cases completed the study (23 with abnormal head posture; 6 without abnormal head posture) . A significant improvement was noted in INS waveform characteristics, mean NAFX score (P < 0.001), and mean binocular visual acuity (P < 0.001) with topical brinzolamide in comparison to baseline as well as placebo. No significant change in head position and stereopsis was noted. No side effects were reported with 3 months of brinzolamide therapy. Conclusions: While brinzolamide shows improvement in visual acuity and NAFX score in idiopathic INS, its clinical significance needs further evidence.

Abstract When lying inside a MRI scanner and even in the absence of any motion, the static magnetic field of MRI scanners induces a magneto-hydrodynamic stimulation of subjects’ vestibular organ (MVS). MVS thereby not only causes a horizontal vestibular nystagmus but also induces a horizontal bias in spatial attention. In this study, we aimed to determine the time course of MVS-induced biases in both VOR and spatial attention inside a 3 T MRI-scanner as well as their respective aftereffects after participants left the scanner. Eye movements and overt spatial attention in a visual search task were assessed in healthy volunteers before, during, and after a one-hour MVS period. All participants exhibited a VOR inside the scanner, which declined over time but never vanished completely. Importantly, there was also an MVS-induced horizontal bias in spatial attention and exploration, which persisted throughout the entire hour within the scanner. Upon exiting the scanner, we observed aftereffects in the opposite direction manifested in both the VOR and in spatial attention, which were statistically no longer detectable after 7 min. Sustained MVS effects on spatial attention have important implications for the design and interpretation of fMRI-studies and for the development of therapeutic interventions counteracting spatial neglect.

Objectives: Even though BPPV is one of the most common causes of vertigo, it is often underdiagnosed and omitted in the diagnosis of patients reporting vertigo. The aim of the study was to establish a diagnostic pattern useful in patients admitted due to vertigo, based on the most common clinical characteristics of patients suffered from posterior canal BPPV (PC-BPPV), horizontal canal BPPV with geotropic (HCG-BPPV) and apogeotropic nystagmus (HCA-BPPV). Methods: The analysis covered the results obtained in 105 patients with a positive result of the Dix-Hallpike maneuver or the supine roll test. The patients were divided into 3 groups based on the BPPV type: gr.1:PC-BPPV (60%); gr.2: HCG-BPPV (27%); gr.3: HCA-BPPV (13%). Patients before the diagnostic maneuvers filled the questionnaire concerning their symptoms and previous diseases. Results: Almost all patients had vertigo during turning over in bed and the character of the symptoms was paroxysmal. The answers to questions about the type of head movement evoked vertigo and how long vertigo lasted were differentiating. The percentages of correct diagnosis speculated by the combined answers were 69.6% in PC-BPPV, 61.8% in HCG-BPPV, and 80% in HCA-BPPV. Conclusions: Basing on those observations there is presented the diagnostic schedule which could be useful in dizziness examination. The above results indicate that a properly collected interview with the patient allows for a high percentage of accurate diagnosis. [ABSTRACT FROM AUTHOR]

Background: Oculocutaneous albinism (OCA) is a genetically heterogeneous condition that is associated with reduced or absent melanin pigment in the skin, hair, and eyes, resulting in reduced vision, high sensitivity to light, and rapid and uncontrolled eye movements. To date, seventeen genes have been associated with OCA including syndromic and non-syndromic forms of the condition. Methods: Whole exome sequencing (WES) was performed to identify pathogenic variants in nine Pakistani families with OCA, with validation and segregation of candidate variants performed using Sanger sequencing. Furthermore, the pathogenicity of the identified variants was assessed using various in-silico tools and 3D protein structural analysis software. Results: WES identified biallelic variants in three genes explaining the OCA in these families, including four variants in TYR, three in OCA2, and two in HPS1, including two novel variants c.667C > T: p.(Gln223*) in TYR, and c.2009 T > C: p.(Leu670Pro) in HPS1. Conclusions: Overall, this study adds further knowledge of the genetic basis of OCA in Pakistani communities and facilitates improved management and counselling services for families suffering from severe genetic diseases in Pakistan. [ABSTRACT FROM AUTHOR]

A 30-year-old woman had 5 days of visual hallucinations, nystagmus, memory impairment and mutism. On examination, she was disorientated with reduced attention span, gazeevoked nystagmus, paratonia and abnormal frontal reflexes. Cerebrospinal fluid (CSF) showed 80 cells, protein 0.41 g/L and glucose 3.2 mmol/L (plasma glucose 5.0 mmol/L). MR scan of the brain showed involvement of limbic and extra-limbic regions and brainstem. Commercial cell-based assays were negative, but tissue-based assays showed neuropil staining, and cell-based assays for anti-metabotropic glutamate receptor 5 (mGluR5) antibodies were positive in serum and CSF. Six months later, she was diagnosed with Hodgkin's lymphoma. This case emphasises the broader clinical spectrum of anti-mGluR5 encephalitis, challenging its initial characterisation as Ophelia syndrome. It underscores the significance of interpreting commercial cell- based assays and advocates for tissue-based assay testing followed by cell-based assay testing in serum and CSF for diagnosing rare autoimmune encephalitis. [ABSTRACT FROM AUTHOR]

Optokinetic nystagmus (OKN) is a reflexive eye movement in response to movement of the viewer's visual environment that consists of a slow phase eye movement in the direction of the stimulus followed by a quick phase in the opposite direction. When tested at the bedside, the slow phases represent smooth pursuit, while the quick phases represent saccades. Normally, OKN is conjugate and symmetric (horizontally and vertically). Abnormalities in the optokinetic response can provide diagnostic and localising value. We describe six clinical scenarios where OKN testing is most useful for the practising neurologist. [ABSTRACT FROM AUTHOR]

Nystagmus induced by applying an intense vibratory stimulus to the skull (SVIN) indicates vestibular functional asymmetry. In unilateral vestibular loss, a 100 Hz bone-conducted vibration given to either mastoid immediately causes a primarily horizontal nystagmus. The test is performed in darkness to avoid visual fixation (VF) but there are no data about how much VF affects the often-intense SVIN. The aim is to analyze the amount of reduction in SVIN when VF is allowed during testing. Thus, all patients seen in a tertiary hospital for vertigo or dizziness with positive SVIN were included. SVIN was recorded for 10 s for each condition: without VF (aSVINwo) and with VF (aSVINw). We obtained an aSVINwo and an aSVINw as average slow-phase velocities (SPV) without and with VF. VF index (FISVIN) was calculated as the ratio of SPV. Among the 124 patients included, spontaneous nystagmus (SN) was found in 25% and the median slow phase velocity (mSPV) (without VF) of SN was 2.6 ± 2.4°/s. Mean FISVIN was 0.27 ± 0.29. FISVIN was 0 in 42 patients, and FISVIN between 0 and 1 was found in 82 (mean FISVIN 0.39 ± 0.02). Fixation suppression was found in all patients with SVIN in cases of peripheral vestibulopathy. FISVIN clearly delineates two populations of patients: with or without a complete visual reduction in nystagmus. [ABSTRACT FROM AUTHOR]

Idiopathic intracranial hypertension (IIH) is a condition characterized by increased pressure around the brain, leading to symptoms including vision changes, headaches, and other neurological issues. The effect of yoga nidra on IIH is still unexplored. This case study investigates the effect of yoga nidra on a 16-year-old female with a known case of IIH with episodic seizures. The patient underwent yoga nidra for six months. The patient's sleep quality, stress, and pain levels were assessed at baseline and after the intervention. The results suggest that yoga nidra had a positive effect in improving sleep quality and reducing the stress level, pain, and reoccurrence of IIH. Hence, future studies with control groups are required to validate the current report findings. [ABSTRACT FROM AUTHOR]

The most common cause of peripheral vertigo is Benign Paroxysmal Positional Vertigo (BPPV) primarily due to involvement of posterior semicircular canal. BPPV due to anterior canal is rare entity. This is a retrospective study, in which data of 628 patients who underwent vertigo test were analyzed. Amongst which 354 were patients of BPPV. It was found that 305 patients had posterior canal BPPV, 18 patients had lateral canal BPPV and 11 patients had anterior canal BPPV. The VNG data of 11 patients with anterior canal BPPV along with their treatment outcomes was analyzed. Of the eleven patients of anterior canal BPPV, ten patients had torsional nystagmus with or without downbeat nystagmus in Deep Head Hanging test. Only one patient had isolated downbeat nystagmus in Supine Head Hanging Test. Patients were treated with modified Yacovino's maneuver. Eight patients had immediate relief with modified Yacovino's repositioning maneuver. One patient had immediate conversion to left posterior canal BPPV and was treated for the same. Two patients presented with delayed conversion to posterior canal BPPV and were treated for the same. Anterior canal BPPV is rare but existent entity. It has a typical torsional and downbeat Nystagmus which is induced by Dix-Hallpike and Deep head hanging test. There is no reversal of nystagmus on getting up. It can be easily corrected by Yacovino's maneuver in the majority of the cases. [ABSTRACT FROM AUTHOR]

To develop and validate a simple questionnaire for the diagnosis of Benign Paroxysmal Positional Vertigo (BPPV) and also to accurately predict the involved side in BPPV. Patients (N = 148) who presented with dizziness to the ENT department were asked to fill out a questionnaire which was formulated to diagnose BPPV and the affected side. Five questions were part of the questionnaire. The fifth question was set to ascertain the affected side in BPPV. All the patients underwent a detailed neuro-otological examination and the findings were noted. The findings of the examination were correlated with the questionnaire findings. The mean age of the patient group was 54.72 years of age. The sensitivity of the questionnaire in detecting BPPV was 94.5%, though in 12.79% (n = 11) the side was not predicted correctly. The specificity of the questionnaire was 91.22%. The positive predictive value of the questionnaire in detecting BPPV was assessed at 94.5%.The questionnaire can be effectively used in predicting BPPV amongst patients presenting with dizziness and thus helps in avoiding unnecessary imaging and referrals to higher centres in view of suspicion of central causes of dizziness. [ABSTRACT FROM AUTHOR]

This study examines a case of lateral canal benign paroxysmal positional vertigo (BPPV) where the sequence of diagnostic positional maneuvers may have influenced the release of some canaliths into the utricle. Partial treatment during BPPV diagnostic maneuvers may complicate side identification during supine roll test, especially in canalolithiasis cases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

See-saw nystagmus (SSN) is a rare form of nystagmus characterised by alternating elevation with incyclotorsion of one eye and concomitant depression with excyclotorsion of the other eye, often due to abnormalities involving the midbrain and parasellar region. Herein, we highlight a rare case of pendular SSN, which demonstrated complete resolution following resection of a pituitary macroadenoma. A patient in their 40s was identified to have SSN and was diagnosed with a pituitary macroadenoma. They underwent an endoscopic endonasal transsellar approach for resection of the pituitary adenoma. Their nystagmus resolved immediately after surgery. From a review of the literature, resolution and/or significant improvement in SSN occurred in 74% of cases following treatment, with 100%, 86% and 50% following treatment for medication-induced, neurological infarcts, and mass-effect aetiologies of SSN, respectively. SSN is a rare entity with a wide array of aetiologies. Identification of the causative aetiology and appropriate treatment can lead to significant improvement or resolution of the nystagmus in most cases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Standard automated perimetry, a psychophysical task performed routinely in eyecare clinics, requires observers to maintain fixation for several minutes at a time in order to measure visual field sensitivity. Detection of visual field damage is confounded by eye movements, making the technique unreliable in poorly attentive individuals and those with pathologically unstable fixation, such as nystagmus. Microperimetry, which utilizes 'partial gaze-contingency' (PGC), aims to counteract eye movements but only corrects for gaze position errors prior to each stimulus onset. Here, we present a novel method of visual field examination in which stimulus position is updated during presentation, which we refer to as 'continuous gaze-contingency' (CGC). In the first part of this study, we present three case examples that demonstrate the ability of CGC to measure the edges of the physiological blind spot in infantile nystagmus with greater accuracy than PGC and standard 'no gaze-contingency' (NoGC), as initial proof-of-concept for the utility of the paradigm in measurements of absolute scotomas in these individuals. The second part of this study focused on healthy observers, in which we demonstrate that CGC has the lowest stimulus positional error (gaze-contingent precision: CGC = ± 0.29°, PGC = ± 0.54°, NoGC = ± 0.81°). CGC test–retest variability was shown to be at least as good as both PGC and NoGC. Overall, CGC is supported as a reliable method of visual field examination in healthy observers. Preliminary findings demonstrate the spatially accurate estimation of visual field thresholds related to retinal structure using CGC in individuals with infantile nystagmus. [ABSTRACT FROM AUTHOR]

Acute vertigo is defined as the perception of movement of oneself or the surroundings in the absence of actual motion and it is a frequent cause for emergency department admissions. The utilization of medical resources and the duration of hospital stay for this kind of symptom is high. Furthermore, the efficiency of brain imaging in the acute phase is low, considering the limited sensitivity of both CT and MRI for diagnosing diseases that are the causes of central type of vertigo. Relying on imaging tests can provide false reassurance in the event of negative results or prolong the in-hospital work-up improperly. On the other hand, clinical examinations, notably the assessment of nystagmus' features, have proven to be highly accurate and efficient when performed by experts. Literature data point out that emergency physicians often do not employ these skills or use them incorrectly. Several clinical algorithms have been introduced in recent years with the aim of enhancing the diagnostic accuracy of emergency physicians when evaluating this specific pathology. Both the 'HINTS and 'STANDING' algorithms have undergone external validation in emergency physician hands, showing good diagnostic accuracy. The objective of this consensus document is to provide scientific evidence supporting the clinical decisions made by physicians assessing adult patients with acute vertigo in the emergency department, particularly in cases without clear associated neurological signs. The document aims to offer a straightforward and multidisciplinary approach. At the same time, it tries to delineate benchmarks for the formulation of local diagnostic and therapeutic pathways, as well as provide a base for the development of training and research initiatives. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the characteristics of positional nystagmus in patients with cupulolithiasis of the posterior semicircular canal-benign paroxysmal positional vertigo (PC-BPPV-cu) to improve clinical diagnostic accuracy. Methods: This study retrospectively analyzed 128 cases of PC-BPPV-cu and 128 cases of canalolithiasis of BPPV (PC-BPPV-ca). General data, intensity, distribution, and the correlation of positional nystagmus were compared between the two groups. Results: Compared to the PC-BPPV-ca group, more cases from the PC-BPPV-cu group initially presented in the emergency department (P <0.05). The most frequent positional nystagmus induced by PC-BPPV-cu was torsional-upbeat nystagmus, characterized by the upper pole of the affected eye beating toward the lower ear and vertically upward (387 cases, 59.7%). It was followed by torsional-downbeat nystagmus, characterized by the upper pole of the unaffected eye beating toward the lower ear and vertically downward (164 cases, 25.3%). The former represented posterior canal excitatory nystagmus (PC-EN), while the latter represented posterior canal inhibitory nystagmus (PC-IN). In the PC-BPPV-cu group, PC-EN was most easily caused by the Half Dix-Hallpike (HH) maneuver on the affected side, while PC-IN was most easily induced by a face-down position (FDP) on the unaffected side at approximately 45° angle (45° FDP). The vertical slow phase velocity (v-SPV) of positional nystagmus was more potent in the affected HH than in other positions with PC-EN (all P < 0.05); the v-SPV of positional nystagmus was greater in the 45° FDP than in different positions with PC-IN (all P < 0.05); the v-SPV of the affected Dix-Hallpike (DH) maneuver in the PC-BPPV-ca group was significantly greater than that of the affected HH maneuver in the PC-BPPV-cu group (P < 0.05). The a priori analysis showed that the strongest correlation with HH positional nystagmus was observed in the affected side roll test, followed by the DH maneuver. Conclusion: In the PC-BPPV-cu group, the HH maneuver most easily induced PC-EN on the affected side, and PC-IN was most easily induced by the 45° FDP. In some cases of PC-BPPV-cu, significant nystagmus was not observed to be induced in the DH position on the affected side; however, vertical rotation nystagmus was induced in the roll-test position on the affected side. In such cases, PC-BPPV-cu diagnosis should be considered, and HH and 45° FDP tests should be conducted to support the diagnosis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This article provides an overview of the labyrinthine system in the human body and its role in motion sickness and spatial perception. It discusses different forms of labyrinthine deactivation and their effects on these processes. The concept of velocity storage, a neural circuit that estimates rotational velocity during self-motion, is explored. The article emphasizes the importance of understanding velocity storage in different contexts, such as space flight, and discusses its potential implications for conditions like mal de débarquement syndrome. The text also includes a list of references to scientific articles related to the study of the vestibular system and its role in spatial orientation and eye movements. These articles provide valuable insights into the functioning of the vestibular system and its importance in maintaining balance and spatial awareness. Additionally, there is a separate document that lists references cited in an article about motion sickness and its underlying mechanisms. These references cover various topics related to motion sickness, including the role of the vestibular system and the neural pathways involved. The article provides a comprehensive overview of current research on motion sickness and its causes. [Extracted from the article]

: Introduction and objective: Nystagmus is a rhythmic and involuntary oscillation of one or both eyes in which a fixation drift and a refixation movement occur. It affects 14-17 out of 10,000 children. There are multiple underlying causes. The objective is to know the different types of non-vestibular nystagmus and non-nystagmic saccadic intrusions, with their characteristics, differential diagnosis, etiologies, diagnosis, and treatment. Method: A narrative bibliographic review has been carried out through the PubMed, Scopus, Google Scholar, and Clinical Key databases. Articles on vestibular nystagmus and clinical cases were excluded. Results: Seventeen articles, book chapters and clinical guidelines of the American Society of Ophthalmology and the Spanish Society of Ophthalmology have been analyzed. Discussion: There are various types of non-vestibular nystagmus that can debut in the pediatric age: infantile nystagmus syndrome, classically called congenital nystagmus, the most frequent; nystagmus syndrome due to maldevelopment of fusion, classically known as latent nystagmus, the second most frequent and related to amblyopia; Spasmus nutans, a syndrome characterized by nystagmus, nodding, and torticollis, the third most frequent; monocular nystagmus such as the Heimann-Bielchowsky phenomenon or myokymia of the superior oblique muscle; alternating periodic nystagmus, which cyclically changes direction, amplitude, and frequency; downbeat nystagmus, most frequent central nystagmus; acquired pendular nystagmus, which may be related to masticatory or palatal disorders; and see-saw nystagmus, with “up and down” eye movement similar to a see-saw. There are also three main types of non-nystagmic saccadic intrusions, which correspond to the opsoclonus syndrome, consisting of disordered multiplanar saccades that can be associated with myoclonus and ataxia ocular bobbing, with vertical saccadic movements and ocular flutter, with horizontal saccadic movements. Conclusions: The characteristics of the different types of non-vestibular nystagmus and non-nystagmic saccadic intrusions and their possible etiologies should be known, since in a large percentage of cases the underlying cause is serious, frequently neurological. In the same way, we must know how to carry out the diagnosis and the therapeutic options that we have within our reach to improve the quality of life of patients. [ABSTRACT FROM AUTHOR]

BACKGROUND: Benign paroxysmal positional vertigo (BPPV) is one of the most frequently diagnosed cause of dizziness among older adults. OBJECTIVE: To investigate the prevalence of BPPV and positional symptoms of dizziness and nystagmus among 75-year-olds and to identify factors associated with BPPV and positional dizziness and nystagmus. METHODS: In this cross-sectional population-based study of 75-78-year-olds in Gothenburg, 887 participants were examined with questions regarding dizziness and health and social factors. A total of 681 participants underwent the Dix-Hallpike test or the side-lying test for BPPV using Video Frenzel goggles. RESULTS: In total 32% reported problems with dizziness (n = 887). The prevalence of BPPV was 4% in the unweighted and 4.5% in the weighted analyses, compensating for selective attrition of women and participants with previous positional dizziness. Positional dizziness without nystagmus was found in 2% and nystagmus without dizziness was found in 9%. Individuals with BPPV and positional dizziness experienced more dizziness in everyday life compared with those with normal tests, while those with positional nystagmus did not. CONCLUSIONS: The estimated prevalence of BPPV among 75-year-olds was 4.5%. Despite weighted analyses, the true prevalence may be higher since many participants with dizziness refused testing. Dizziness was associated with fear and discomfort so strong that around 20% of the participants declined testing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of topical carbonic anhydrase inhibitor (brinzolamide) versus placebo on visual function and waveforms in infantile nystagmus syndrome (INS). Design: Prospective, placebo‑controlled, double‑blind, cross‑over study. Methods: Setting‑ A tertiary eye care center. Patients‑ Cases of idiopathic INS with and without abnormal head posture aged ≥10 years who had not received previous treatment for nystagmus. Intervention‑ Patients were randomized into two groups. Group 1 was given placebo for 3 months, and after a washout period of 7 days started on topical brinzolamide for the next 3 months. In group 2, the order was reversed. The drops were administered topically three times (every 8 hours) in both eyes. Outcome measure‑ Binocular best corrected visual acuity (BCVA) using the ETDRS chart, eXpanded nystagmus acuity function (NAFX) score and INS waveforms obtained from eye movement recordings, intraocular pressure (IOP) by Goldmann applanation tonometer, near stereopsis by TNO stereo test, and change in abnormal head posture before and after intervention in the null position. Results: A total of 29 cases completed the study (23 with abnormal head posture; 6 without abnormal head posture). A significant improvement was noted in INS waveform characteristics, mean NAFX score (P < 0.001), and mean binocular visual acuity (P < 0.001) with topical brinzolamide in comparison to baseline as well as placebo. No significant change in head position and stereopsis was noted. No side effects were reported with 3 months of brinzolamide therapy. Conclusions: While brinzolamide shows improvement in visual acuity and NAFX score in idiopathic INS, its clinical significance needs further evidence. [ABSTRACT FROM AUTHOR]

The article focuses on the case of a previously healthy 3-year-old presenting with unsteady gait, nystagmus, and lower extremity weakness, highlighting the importance of thorough physical examination and the differential diagnosis process. Topics include the clinical presentation, diagnostic evaluation, and management of acute neurological symptoms in pediatric patients, emphasizing the need for prompt recognition and intervention in cases of acute neurological deterioration.

This letter to the editors of the Journal of Neurology discusses a new maneuver for identifying positional nystagmus in patients with subjective benign paroxysmal positional vertigo (BPPV). BPPV is a common cause of dizziness/vertigo, and this new maneuver aims to diagnose a rare form of BPPV called short-arm PC-BPPV. The authors propose a mechanism for the induced nystagmus and suggest further research is needed to understand the relationship between subjective BPPV and short-arm PC-BPPV. The authors conclude that the findings in this patient expand the clinical spectrum of BPPV and could provide an objective sign for the diagnosis of PC-BPPV from the short arm. [Extracted from the article]

Introduction: Benign paroxysmal positional vertigo (BPPV) is a vestibular disease characterized by brief positional vertigo. When examined, characteristic patterns of positional nystagmus (PN) are found with specific head position changes. Previous studies have shown a high prevalence of PN among vestibular healthy subjects. Considering the current diagnostic criteria of BPPV and the potentially high prevalence of PN in healthy individuals, this raises the question of potential over diagnosing BPPV, if diagnostics are based exclusively upon objective findings. This study aims to determine the prevalence of PN within a healthy, adult population and furthermore include a characterization of the PN observed. Methods: This is a prospective cross-sectional study. 78 subjects were included. The subjects underwent four standardized positional tests for BPPV in a mechanical rotational chair while using a VNG-goggle to monitor and record eye movements. Results: Positional nystagmus was recorded in 70.5% (55/78) of the subjects. Of the 55 subjects, who presented with PN, 81.8% (45/55) had upbeating PN. The 95th percentile of the maximum a-SPV was found to be 10.4 degrees per second, with a median of 4. Five subjects (6.4%) in total presented with PN mimicking BPPV. Conclusion: This study found PN to be a common finding within a healthy, adult population based on the high prevalence of PN in the study population. Upbeating PN mimicking posterior canalolithiasis was found in numerous subjects. The authors recommend a cautious approach when diagnosing BPPV, especially in cases of purely vertical PN (without a torsional component) and if no vertiginous symptoms are present during Dix-Hallpike and Supine Roll Test examinations. [ABSTRACT FROM AUTHOR]

Downbeat nystagmus (DBN) is a neuro-otological finding frequently encountered by clinicians dealing with patients with vertigo. Since DBN is a finding that should be understood because of central vestibular dysfunction, it is necessary to know how to frame it promptly to suggest the correct diagnostic-therapeutic pathway to the patient. As knowledge of its pathophysiology has progressed, the importance of this clinical sign has been increasingly understood. At the same time, clinical diagnostic knowledge has increased, and it has been recognized that this sign may occur sporadically or in association with others within defined clinical syndromes. Thus, in many cases, different therapeutic solutions have become possible. In our work, we have attempted to systematize current knowledge about the origin of this finding, the clinical presentation and current treatment options, to provide an overview that can be used at different levels, from the general practitioner to the specialist neurologist or neurotologist. [ABSTRACT FROM AUTHOR]