Early Manifestation of Benign Paroxysmal Positional Vertigo: A Case Report

Introduction

Benign paroxysmal positional vertigo (BPPV) is an inner ear disorder with a heterogeneous etiology, often linked to preceding infections, head injuries, or vestibular neuronitis. While it is commonly observed in the elderly, its occurrence in the pediatric population is rare. To our knowledge, there have been no reported cases of BPPV in patients younger than 5 years.

Case Presentation

A 4.5-month-old female infant was admitted with episodes of paroxysmal nystagmus. Parents reported fast horizontal eye movements lasting up to 30 s, with one episode accompanied by vomiting. Comprehensive differential diagnosis was considered from epileptic nystagmus to intoxications and both central and peripheral vestibular etiologies. During the observation on ward, connection between the baby's positioning and nystagmus was identified. The diagnostic roll test confirmed a transient positional geotropic nystagmus. The diagnosis aligned with BPPV characteristics, pointing to the right lateral semicircular canal canalolithiasis. A successful Lempert roll maneuver was performed with prompt effect. To further support the diagnosis and research, we introduced a semiautomatic video-oculography method.

Conclusion

This case highlights a rare instance of BPPV in an infant. The clinical findings combined with the effectiveness of the repositioning maneuvers support the diagnosis of right lateral semicircular canal lithiasis. Despite the rarity of this condition in such a young-age group, the need for thorough diagnostic evaluations is emphasized. In order to document the case, we also present a semiautomatic video analysis pipeline for analyzing abnormal eye movements in a home setting.

Three-dimensional analysis of per-rotational nystagmus

BACKGROUND

Head rotation produces a vestibulo-ocular reflex (VOR). In horizontal rotation, not only lateral semicircular canals but also posterior semicircular canals are stimulated, because posterior canals cupulae are not horizontal in the sitting position. Therefore, theoretical nystagmus is horizontal and torsional. Convection of endolymph does not occur, because the centre of head rotation is a dens of the second cervical vertebra, not the center of lateral canal. Although per-rotational nystagmus is a result of VOR, whether it could be explained by the movement of cupula remains undetermined. To answer this question, we analysed per-rotational nystagmus using three-dimensional video-oculography.

OBJECTIVE

To clarify whether per-rotational nystagmus is the same as the physical movement of cupula (theoretical nystagmus).

MATERIALS AND METHODS

Five healthy human were evaluated. The participant's head was rotated (sinusoidal yaw rotation) manually (frequency, 0.33 Hz; amplitude, 60°). The experiment was performed in a dark, with the participant's eyes open. Nystagmus was recorded and converted into digital data.

RESULTS

In all participants, the direction of nystagmus was rightward on rightward rotation and leftward on leftward rotation. In all participants, nystagmus was purely horizontal.

CONCLUSIONS

Practical per-rotational nystagmus differs completely from the theoretical nystagmus. Therefore, VOR is strongly influenced by the central nervous system.

Oculomotor fatigability with decrements of saccade and smooth pursuit for diagnosis of myasthenia gravis

BACKGROUND AND OBJECTIVES

As the efficacy of current diagnostic methods for myasthenia gravis (MG) remains suboptimal, there is ongoing interest in developing more effective diagnostic models. As oculomotor fatigability is one of the most common and diagnostic symptoms in MG, we aimed to investigate whether quantitative saccadic and smooth-pursuit fatigability analyses with video-oculography (VOG) are useful for diagnosis of MG.

METHODS

A convenience cohort of 46 MG patients was recruited prospectively, including 35 with ocular and 11 with generalized MG (mean age, 50.9 ± 14.5 years; 17 females); 24 healthy controls (HCs) (mean age, 50.6 ± 16.3 years; 13 females) also were enrolled. Seventy-five repetitive saccades and smooth pursuits were recorded in ranges of 20° (horizontal plane) and 15° (vertical plane) using a three-dimensional VOG system. Based on the oculomotor range of the second saccade and smooth pursuit and the mean ranges of the last five of each, the estimated decrements (%) reflecting oculomotor fatigability were calculated.

RESULTS

The baseline oculomotor ranges did not show significant difference between the MG and HCs groups. However, following repetitive saccades and pursuits, the oculomotor ranges were decreased substantially during the last five cycles compared to baseline in the MG group. No such decrements were observed in the HC group (p < 0.01, Mann-Whitney U test). Receiver operating characteristic (ROC) analysis revealed that repetitive vertical saccades yielded the best differentiation between the MG and HC groups, with a sensitivity of 78.3% and specificity of 95.8% when using a decrement with an amplitude of 6.4% as the cutoff.

CONCLUSION

This study presents an objective and reproducible method for measuring decrements of oculomotor ranges after repetitive saccadic and pursuit movements. Quantification of oculomotor fatigability using VOG could be a sensitive and specific diagnostic tool for MG and allows easy, cost-effective, accurate, and non-invasive measurements.

CLASSIFICATION OF EVIDENCE

This study provides class III evidence that VOG-based quantification of saccadic and pursuit fatigability accurately identifies patients with MG.

Analysis of 30 patients with cupulolithiasis of the posterior semicircular canal

BACKGROUND

The diagnostic characteristics of patients with cupulolithiasis of the posterior semicircular canal are persistent torsional nystagmus in the supine position and persistent torsional nystagmus (opposite direction) in the nose-down position, which are caused by the affected canal becoming gravity sensitive.

OBJECTIVE

To investigate the clinical features of posterior cupulolithiasis.

MATERIALS AND METHODS

We interviewed 30 consecutive patients with cupulolithiasis of the posterior canal and categorized them by onset time into the following four groups: (1) during sleep; (2) at the time of awakening; (3) morning; and (4) afternoon. We defined disease duration as the period from onset to the day when we detected remission of positional nystagmus.

RESULTS

Time of awakening was the most common onset time. The mean disease duration was 18.2 days, and 90% of patients achieved cure within 1 month.

CONCLUSIONS

Physicians should take into account the duration of nystagmus, because cupulolithiasis of posterior canal exists. The etiology of posterior cupulolithiasis is closely related to sleep, because time of awakening is the most common onset time of vertigo. Most patients with posterior cupulolithiasis cure within 1 month.

Automated nystagmus detection: Accuracy of slow-phase and quick-phase algorithms to determine the presence of nystagmus

PURPOSE

To verify the accuracy of automated nystagmus detection algorithms.

METHOD

Video-oculography (VOG) plots were analyzed from consecutive patients with dizziness presenting to a neurology clinic. Data were recorded for 30 s in upright position with fixation block. For automated nystagmus detection, slow-phase algorithm parameters included mean and median slow-phase velocity (SPV), and slow-phase duration ratio. Quick-phase algorithm parameters included saccadic difference and saccadic ratio. For verification, two independent blinded assessors reviewed VOG traces and videos and coded presence or absence of nystagmus. Assessor consensus was used as reference standard. Accuracy of slow-phase and quick-phase algorithm parameters were compared, and ROC analysis was performed.

RESULTS

Among 524 analyzed VOG traces, 99 were verified as nystagmus present and 425 were verified as nystagmus absent. Prevalence of nystagmus in the sample population was 18.9%. In ROC analysis, areas under the curve of individual algorithm parameters were 0.791-0.896. With optimal thresholds for determining presence or absence of nystagmus, algorithm sensitivity (70.7-87.9%), specificity (71.8-84.0%), and negative predictive value (91.7-96.4%) were ideal, but positive predictive value (38.8-53.4%) was not ideal. Combining algorithm parameters using logistic regression models mildly improved detection accuracy.

CONCLUSION

Both slow-phase and fast-phase algorithms were accurate for detecting nystagmus. Due to low positive predictive value, the utility of independent automated nystagmus detection systems is limited in clinical settings with low prevalence of nystagmus. Combining parameters using logistic regression models appears to improve detection accuracy, indicating that machine learning may potentially optimize the accuracy of future automated nystagmus detection systems.

Video-oculographic biomarkers for evaluating vertical ocular dysfunction in progressive supranuclear palsy

INTRODUCTION

Progressive supranuclear palsy (PSP) patients show reduced amplitude and velocity of vertical saccades, but saccadic abnormalities have also been reported in Parkinson's disease (PD). We investigated amplitude and velocity of vertical saccades in PSP and PD patients, to establish the best video-oculographic (VOG) parameters for PSP diagnosis.

METHODS

Fifty-one PSP patients, 113 PD patients and 40 controls were enrolled. The diagnosis was performed on a clinico-radiological basis (MR Parkinsonism index [MRPI] and MRPI 2.0). We used VOG to assess the diagnostic performances of saccadic amplitude, peak velocity, and their product (AxV) in upward or downward direction and in vertical gaze (upward and downward averaged) in distinguishing PSP from PD patients. The vestibulo-ocular reflex, necessary to establish the supranuclear nature of ocular dysfunction, was evaluated clinically.

RESULTS

PSP patients showed significantly reduced amplitude and peak velocity of ocular saccades in upward and downward directions compared to PD and healthy subjects. In PD patients, upward gaze amplitude was lower than in controls. In vertical gaze, the peak velocity showed 99.1% specificity and 54.7% sensitivity for PSP classification. The AxV product showed high specificity (94.7%) and sensitivity (84.3%) and yielded higher accuracy (91.5%) than velocity and amplitude used alone in distinguishing PSP from PD.

CONCLUSION

Our study demonstrates that the peak velocity of vertical saccades was a very low sensitive parameter and cannot be used alone for PSP diagnosis. A new index combining amplitude and peak velocity in vertical gaze seems the most suitable video-oculographic biomarker for differentiating PSP from PD and controls.

Automated alternate cover test for 'HINTS' assessment: a validation study

Objective

The alternate cover test (ACT) in patients with acute vestibular syndrome is part of the ‘HINTS’ battery test. Although quantitative, the ACT is highly dependent on the examiner’s experience and could theoretically vary greatly between examiners. In this study, we sought to validate an automated video-oculography (VOG) system based on eye tracking and dedicated glasses.

Methods

We artificially induced a vertical strabismus to simulate a skew deviation on ten healthy subjects, aged from 26 to 66, using different press-on Fresnel prisms on one eye while recording eye position with VOG of the contralateral eye. We then compared the system’s performance to that of a blinded trained orthoptist using conventional, semi-quantitative method of skew measurement known as the alternate prism cover test (APCT) as a gold standard.

Results

We found a significant correlation between the reference APCT and the Skew VOG (Pearson’s R² = 0.606, p < 0.05). There was a good agreement between the two tests (intraclass correlation coefficient 0.852, 95 CI 0.728–0.917, p < 0.001). The overall accuracy of the VOG was estimated at 80.53% with an error rate of 19.46%. There was no significant difference in VOG skew estimations compared with the gold standard except for very small skews.

Conclusions

VOG offers an objective and quantitative skew measurement and proved to be accurate in measuring vertical eye misalignment compared to the ACT with prisms. Precision was moderate, which mandates a sufficient number of tests per subject.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-06998-w.

Acute vestibular syndrome: is skew deviation a central sign?

Objective

Skew deviation results from a dysfunction of the graviceptive pathways in patients with an acute vestibular syndrome (AVS) leading to vertical diplopia due to vertical ocular misalignment. It is considered as a central sign, however, the prevalence of skew and the accuracy of its test is not well known .

Methods

We performed a prospective study from February 2015 until September 2020 of all patients presenting at our emergency department (ED) with signs of AVS. All patients underwent clinical HINTS and video test of skew (vTS) followed by a delayed MRI, which served as a gold standard for vestibular stroke confirmation.

Results

We assessed 58 healthy subjects, 53 acute unilateral vestibulopathy patients (AUVP) and 24 stroke patients. Skew deviation prevalence was 24% in AUVP and 29% in strokes. For a positive clinical test of skew, the cut-off of vertical misalignment was 3 deg with a very low sensitivity of 15% and specificity of 98.2%. The sensitivity of vTS was 29.2% with a specificity of 75.5%.

Conclusions

Contrary to prior knowledge, skew deviation proved to be more prevalent in patients with AVS and occurred in every forth patient with AUVP. Large skew deviations (> 3.3 deg), were pointing toward a central lesion. Clinical and video test of skew offered little additional diagnostic value compared to other diagnostic tests such as the head impulse test and nystagmus test. Video test of skew could aid to quantify skew in the ED setting in which neurotological expertise is not always readily available.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10692-6.

Bedside video-oculographic evaluation of eye movements in acute supratentorial stroke patients: A potential biomarker for hemispatial neglect

BACKGROUND AND PURPOSE

The presence of hemispatial neglect adversely affects functional outcomes in stroke patients; consequently, it warrants early targeted rehabilitative intervention. Nevertheless, hemispatial neglect in the acute phase of stroke has often been underdiagnosed. In this study, we aimed to detect hemispatial neglect at the bedside in acute stroke patients by measuring eye movements using video-oculography (VOG).

METHODS

Forty-seven patients with acute unilateral supratentorial stroke were enrolled. We quantitatively measured horizontal saccade (latency, velocity, and amplitude) and smooth pursuit (gain) at the bedside using VOG and compared these variables with scores on the Behavioral Inattention Test (BIT), a screening battery to assess hemispatial neglect.

RESULTS

Contralesional saccade latency, velocity, and amplitude, and ipsilesional smooth pursuit gain were suppressed compared with those in the opposite directions (p = 0.08, 0.02, 0.04, and 0.02, respectively). These directional ocular hypokinesia values correlated with the total BIT score (correlation coefficients -0.53, 0.48, 0.51, and 0.39, respectively). The association was significant even after adjusting for age and stroke severity.

CONCLUSIONS

Eye movement measurements performed using VOG significantly correlated with the tendency for hemispatial neglect in acute supratentorial stroke patients. Bedside VOG measurement may be a simple biomarker for detecting hemispatial neglect even in patients in the supine position during the acute phase of stroke.

Diagnostic value of video-oculography in progressive supranuclear palsy: a controlled study in 100 patients

Background

The eponymous feature of progressive supranuclear palsy (PSP) is oculomotor impairment which is one of the relevant domains in the Movement Disorder Society diagnostic criteria.

Objective

We aimed to investigate the value of specific video-oculographic parameters for the use as diagnostic markers in PSP.

Methods

An analysis of video-oculography recordings of 100 PSP patients and 49 age-matched healthy control subjects was performed. Gain of smooth pursuit eye movement and latency, gain, peak eye velocity, asymmetry of downward and upward velocities of saccades as well as rate of saccadic intrusions were analyzed.

Results

Vertical saccade velocity and saccadic intrusions allowed for the classification of about 70% and 56% of the patients, respectively. By combining both parameters, almost 80% of the PSP patients were covered, while vertical velocity asymmetry was observed in approximately 34%. All parameters had a specificity of above 95%. The sensitivities were lower with around 50–60% for the velocity and saccadic intrusions and only 27% for vertical asymmetry.

Conclusions

In accordance with oculomotor features in the current PSP diagnostic criteria, video-oculographic assessment of vertical saccade velocity and saccadic intrusions resulted in very high specificity. Asymmetry of vertical saccade velocities, in the opposite, did not prove to be useful for diagnostic purposes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10522-9.

Study of reliability and validity of VOG Perea® and GazeLab® and calculation of the variability of their measurements

OBJECTIVE

To determine the reliability and validity of VOG Perea® (VP) and GazeLab® (GL), their correlation and concordance with cover test (CT), and define the margins of variability of the measurement of angle deviation in primary position.

METHODS

Forty-four orthotropic patients were included. Alternating prism CT, an examination with VP, and GL were performed. Intraclass correlation coefficient (ICC) was calculated to determine the reliability, and mean comparison was used to study validity. Correlation coefficient (R) between CT and each video-oculographer was calculated. Bland-Altman diagrams were used to determine concordance. All measurements were expressed in prismatic dioptres (PD).

RESULTS

The mean horizontal deviation was -0.571 PD with CT; 0.22 PD with VP and 0.4 PD with GL. ICC was 0.246 (95% CI: [-0.402]-0.595) in GL and 0.984 [95% CI: 0.970-0.992)] in VP. Mean comparison between CT and GL was -0.9286 (CI 95%: [-1.822]-[0.0355], P=.042) and -0.8423 (95% CI: [-1.7190]-0.03450, P=.0593) for CT-VP. Correlation coefficient for VP was R=0.5704 (95% CI: 0.319-0.747, P=.0001) and R=0.4539 (95% CI: 0.174-0.666, P=.0025) for GL. Margins of variability for a single horizontal measurement in primary position with VP were±5.22 PD and±2 DP for GL.

CONCLUSION

Both VP and GL are reliable and valid devices. Margins of variability for a horizontal measurement are ±5.22 PD in VP and±2 PD in GL.

Diagnosing vestibular hypofunction: an update

Unilateral or bilateral vestibular hypofunction presents most commonly with symptoms of dizziness or postural imbalance and affects a large population. However, it is often missed because no quantitative testing of vestibular function is performed, or misdiagnosed due to a lack of standardization of vestibular testing. Therefore, this article reviews the current status of the most frequently used vestibular tests for canal and otolith function. This information can also be used to reach a consensus about the systematic diagnosis of vestibular hypofunction.

Eye movement biomarkers allow for the definition of phenotypes in Gaucher Disease

BACKGROUND

Neurological forms of Gaucher disease, the inherited disorder of β-Glucosylceramidase caused by bi-allelic variants in GBA1, is a progressive disorder which lacks a disease-modifying therapy. Systemic manifestations of disease are effectively treated with enzyme replacement therapy, however, molecules which cross the blood-brain barrier are still under investigation. Clinical trials of such therapeutics require robust, reproducible clinical endpoints to demonstrate efficacy and clear phenotypic definitions to identify suitable patients for inclusion in trials. The single consistent clinical feature in all patients with neuronopathic disease is the presence of a supranuclear saccadic gaze palsy, in the presence of Gaucher disease this finding serves as diagnostic of 'type 3' Gaucher disease.

METHODS

We undertook a study to evaluate saccadic eye movements in Gaucher patients and to assess the role of the EyeSeeCam in measuring saccades. The EyeSeeCam is a video-oculography device which was used to run a protocol of saccade measures. We studied 39 patients with non-neurological Gaucher disease (type 1), 21 patients with type 3 (neurological) disease and a series of 35 healthy controls. Mean saccade parameters were compared across disease subgroups.

RESULTS

We confirmed the saccadic abnormality in patients with type 3 Gaucher disease and identified an unexpected subgroup of patients with type 1 Gaucher disease who demonstrated significant saccade parameter abnormalities. These patients also showed subtle neurological findings and shared a GBA1 variant.

CONCLUSIONS

This striking novel finding of a potentially attenuated type 3 Gaucher phenotype associated with a specific GBA1 variant and detectable saccadic abnormality prompts review of current disease classification. Further, this finding highlights the broad spectrum of neuronopathic Gaucher phenotypes relevant when designing inclusion criteria for clinical trials.

Premature saccades: A detailed physiological analysis

OBJECTIVE

Premature saccades (PSs) are those made with latencies too short for the direction and amplitude to be specifically programmed. We sought to determine the minimum latency needed to establish accurate direction and amplitude, and observed what occurs when saccades are launched before this minimum latency.

METHODS

In Experiment 1, 249 normal subjects performed the gap saccade task with horizontal targets. In Experiment 2, 28 normal subjects performed the gap saccade task with the targets placed in eight directions. In Experiment 3, 38 normal subjects, 49 patients with Parkinson's disease (PD), and 10 patients with spinocerebellar degeneration (SCD) performed the gap saccade task with horizontal targets.

RESULTS

In Experiment 1, it took 100 ms to accurately establish saccade amplitudes and directions. In Experiment 2, however, the latencies needed for accurate amplitude and direction establishment were both approximately 150 ms. In Experiment 3, the frequencies of PSs in patients with PD and SCD were lower than those of normal subjects.

CONCLUSIONS

The saccade amplitudes and directions are determined simultaneously, 100-150 ms after target presentation. PSs may result from prediction of the oncoming target direction or latent saccade activities in the superior colliculus.

SIGNIFICANCE

Saccade direction and amplitude are determined simultaneously.

Saccadic reaction time and ocular findings in phenylketonuria

Background

Phenylketonuria (PKU) is an inherited metabolic disorder characterized by reduced activity of phenylalanine hydroxylase resulting in elevated blood phenylalanine (Phe) concentration. Despite some obvious ocular changes, the disorder has been poorly recognized by ophthalmologists. Neurophysiologic tests imply prolonged reaction time correlating with increased phenylalanine blood concentrations. We aimed to test saccadic reaction time in PKU patients in dependency of blood phenylalanine concentrations.

Methods

Nineteen biochemically diagnosed PKU patients and 100 controls completed comprehensive ophthalmologic and orthoptic examinations including saccadometry by infrared based video-oculography. Peak velocity, gain, and particularly latency of reflexive saccades were compared to controls, and regression analysis was performed.

Results

Latency of reflexive saccades was not associated with the current phenylalanine concentration. Although in 10 out of 19 patients phenylalanine concentrations were outside the age-related therapeutic range, latency differed little between PKU patients and the controls, as well as peak velocity and gain. Ocular findings occurred as partial hypopigmentation of the iris in one late diagnosed patient aged 36 years, and as bilateral cataracts (possibly due to steroid intake) with refractive amblyopia, strabismus, high myopia, and glaucoma in another late diagnosed patient aged 46 years. Visual acuity was reduced in eight PKU patients.

Conclusions

Saccadometry, particularly saccadic reaction time, is not useful in the monitoring of phenylketonuria. Ophthalmic examination is recommended in PKU patients, as the occurrence of ocular pathologies was relatively high.

Video-oculography in multiple sclerosis: Links between oculomotor disorders and brain magnetic resonance imaging (MRI)

BACKGROUND

Eye movement abnormalities (EMA) are common in multiple sclerosis (MS). However, type and severity according to the MS stage are poorly known, especially in Radiologically Isolated Syndrome (RIS) and in Clinically Isolated Syndrome (CIS). Although MRI has been included in the MS diagnostic criteria, there may be clinical-radiological dissociation.

OBJECTIVE

To analyze by video-oculography (VOG) prevalence of EMA in different MS phenotypes and study correlations with brain and cervical cord MRI T2 lesions location.

METHODS

76 participants were prospectively recruited (12 RIS, 10 CIS, 11 relapsing-remitting-MS, 10 secondary progressive-MS, 10 primary progressive MS and 23 gender and age-matched healthy controls). We analyzed fixations, anti-saccades, horizontal and vertical reflex saccades and smooth pursuit.

RESULTS

EMA were frequent and of gradual severity from RIS to progressive forms. Internuclear ophthalmoplegia (INO) and centripetal hypermetria were strong arguments for the diagnosis of a demyelinating disorder versus a control population. Some EMA were linked to infratentorial T2 lesion location, but others like INO were not.

CONCLUSION

This study confirm that EMA are common in all MS phenotypes, even at the earliest stages. VOG can be useful to detect demyelinating process at preclinical stage by highlighting subclinical EMA even in absence of characteristic lesions visible on MRI.

A comprehensive monocentric ophthalmic study with Gaucher disease type 3 patients: vitreoretinal lesions, retinal atrophy and characterization of abnormal saccades

Background

The differentiation between Gaucher disease type 3 (GD3) and type 1 is challenging because pathognomonic neurologic symptoms may be subtle and develop at late stages. The ophthalmologist plays a crucial role in identifying the typical impairment of horizontal saccadic eye movements, followed by vertical ones. Little is known about further ocular involvement. The aim of this monocentric cohort study is to comprehensively describe the ophthalmological features of Gaucher disease type 3. We suggest recommendations for a set of useful ophthalmologic investigations for diagnosis and follow up and for saccadometry parameters enabling a correlation to disease severity.

Methods

Sixteen patients with biochemically and genetically diagnosed GD3 completed ophthalmologic examination including optical coherence tomography (OCT), clinical oculomotor assessment and saccadometry by infrared based video-oculography. Saccadic peak velocity, gain and latency were compared to 100 healthy controls, using parametric tests. Correlations between saccadic assessment and clinical parameters were calculated.

Results

Peripapillary subretinal drusen-like deposits with retinal atrophy (2/16), preretinal opacities of the vitreous (4/16) and increased retinal vessel tortuosity (3/16) were found. Oculomotor pathology with clinically slowed saccades was more frequent horizontally (15/16) than vertically (12/16). Saccadometry revealed slowed peak velocity compared to 100 controls (most evident horizontally and downwards). Saccades were delayed and hypometric. Best correlating with SARA (scale for the assessment and rating of ataxia), disease duration, mSST (modified Severity Scoring Tool) and reduced IQ was peak velocity (both up- and downwards). Motility restriction occurred in 8/16 patients affecting horizontal eye movements, while vertical motility restriction was seen less frequently. Impaired abduction presented with esophoria or esotropia, the latter in combination with reduced stereopsis.

Conclusions

Vitreoretinal lesions may occur in 25% of Gaucher type 3 patients, while we additionally observed subretinal lesions with retinal atrophy in advanced disease stages. Vertical saccadic peak velocity seems the most promising “biomarker” for neuropathic manifestation for future longitudinal studies, as it correlates best with other neurologic symptoms. Apart from the well documented abduction deficit in Gaucher type 3 we were able to demonstrate motility impairment in all directions of gaze.

Adduction-Abduction Asymmetry in Saccades During Video-Oculographic Monocular Recording: A Word of Caution

In eye movement examination, video-oculographic monocular recording has become more popular than electro-oculographic binocular recording. The aim of this study was to examine the characteristics of monocular movements recorded using video-oculography. In 66 healthy subjects, the horizontal saccades and smooth pursuit eye movements of the right eye within a range of 30º were evaluated using a video-oculographic eye movement recording system. Saccade latency, velocity, accuracy, and smooth pursuit gain were measured and analysed by age and direction. Saccade parameters (latency, velocity, and amplitude) and smooth pursuit gain deteriorated with age in healthy subjects. Saccade velocity and accuracy were significantly larger during adduction than during abduction. The smooth pursuit gain did not differ between adduction and abduction. In conclusion, unlike smooth pursuit eye movements, saccadic eye movements have adduction-abduction asymmetry. In video-oculographic monocular recording of saccades, it is necessary to recognise the possibility of the existence of adduction-abduction asymmetry.

Influence of ambient air pressure changes on vestibular symptoms after stapes surgery

OBJECTIVE

To examine if vestibular irritation after stapes surgery may be provoked by pressure changes across the tympanic membrane, which consecutively results in displacements of the ossicular chain and the piston prosthesis suspended to it.

METHODS

In this prospective study 15 patients (13 female, 2 male) received unilateral stapes surgery (4 left, 11 right ear) with stapedotomy (n=14) or stapedectomy (n=1) at an academic tertiary referral center. Surgery was performed under local anesthesia via a transmeatal approach with a piston prosthesis 0.4×4.5mm. The fixation of the stapes, the exclusion of a malleus head fixation, and the gliding capacity of the malleus-incus joint were examined intraoperatively. A pure tone audiogram at four frequencies, a tympanometry with simultaneous video-oculography (VOG), caloric testing, and posturography with and without simultaneous tympanometry were performed six days before surgery, six weeks and three months after surgery, respectively.

RESULTS

The mean air bone gap improved significantly from 25 (±8) dB preoperatively to 10 (±6) dB after surgery. In the tympanometry with simultaneous VOG only two patients showed nystagmus beats into the operated ears during only one of the two follow-up appointments. All other patients did not show any vestibular symptoms or nystagmus during any of the follow-up appointments. In the combined testing of posturography and tympanometry no patient showed any pathological findings.

CONCLUSION

In patients who underwent stapes surgery with a piston prosthesis no vestibular symptoms can be provoked by pressure changes in the external auditory canal.

A quantitative analysis method for comitant exotropia using video-oculography with alternate cover

Background

The purpose of this study was to evaluate the efficacy of a quantitative analysis method for comitant exotropia using video-oculography (VOG) with alternate cover.

Methods

Thirty-four subjects with comitant exotropia were included. Two independent ophthalmologists measured the angle of ocular deviation using the alternate prism cover test (APCT). The video files and data of changes in ocular deviation during the alternate cover test were obtained using VOG. To verify the accuracy of VOG, the value obtained using VOG and the angle of a rotating model eye were compared, and a new linear equation was subsequently derived using these data. The calculated values obtained using VOG were compared with those obtained using the APCT.

Results

Rotation of the model eye and the values obtained using VOG demonstrated excellent positive correlation (R = 1.000; p < 0.001). A simple linear regression model was obtained: rotation of the model eye = 0.978 × value obtained using VOG for a model eye – 0.549. The 95% limit of agreement for inter-observer variability was ±4.63 prism diopters (PD) for APCT and that for test-retest variability was ±3.56 PD for the VOG test. The results of APCT and calculated VOG test demonstrated a strong positive correlation. Bland-Altman plots revealed no overall tendency for the calculated values obtained from VOG to differ from those obtained using APCT.

Conclusions

VOG with alternate cover is a non-invasive and accurate tool for quantitatively measuring and recording ocular deviation. In particular, it is independent of the proficiency of the examiner and, can therefore, be useful in the absence of skilled personnel.

Trial registration

ClinicalTrial.gov, NCT03119311, Date of registration: 04/17/2017, Date of enrolment of the first participant to the trial: 04/25/2017.

Topical brinzolamide in congenital nystagmus: A retrospective study

OBJECTIVE

To evaluate the effect of treatment with topical brinzolamide on visual acuity and nystagmus intensity in patients with congenital nystagmus.

MATERIAL AND METHODS

A retrospective study was designed in which the clinical records of 14 patients with congenital nystagmus were reviewed. All patients underwent a complete ophthalmological examination and a Perea video-oculography (VOG) before, and three days after, initiation of treatment with topical brinzolamide (Azopt). Five expert researchers evaluated the intensity of nystagmus by video before and after treatment. Finally, the subjective improvement of the patients was recorded.

RESULTS

Statistically significant differences were found in pre- and post-treatment binocular near visual acuity. A slight increase in the frequency of nystagmus was found, which was statistically significant with the horizontal gaze to the left and with the gaze downwards (P=.04, P=.03, respectively). The kappa index concordance between the researchers evaluating the intensity of nystagmus was 0.014. Only two of the patients noticed improvement in visual acuity, and one patient noticed improvement in the aesthetic aspect.

CONCLUSIONS

In spite of an improvement in nystagmus, it was slight, not cosmetically appreciable by patients in most cases, and was not related to a significant improvement in visual acuity or in patient quality of life. Further studies are needed to evaluate the effects of topical brinzolamide, and to establish potential therapeutic indications in nystagmus.

Effect of common antivertiginous agents on the high velocity vestibulo-ocular reflex

OBJECTIVE

It has long been suggested that antivertiginous medications exert their symptomatic effect through inhibition of the vestibulo-ocular reflex (VOR). We tested this hypothesis by directly measuring the VOR after administration of three agents from different substance classes: an antihistamine, a benzodiazepine and a calcium channel antagonist.

METHODS

The gain and the variability of the high velocity VOR was assessed using video head impulses (vHIT) under the following conditions: baseline, after dimenhydrinate, after diazepam and after cinnarizine.

RESULTS

We found that all three medications did not change any VOR gain or variability parameter: At 60ms, the gain was 0.95 at baseline, 0.99 under dimenhydrinate, 0.99 under diazepam and 0.96 under cinnarizine. The gain variability across repetitive head impulses remained also uninfluenced.

CONCLUSIONS

The human high frequency VOR remains robust to pharmacological perturbations at common clinical doses and the assumption that symptomatic vertigo relief is achieved merely through impairment of the VOR requires re-examination.

SIGNIFICANCE

Alternative mechanisms of pharmacological action might be operant, such as the modulation of vestibulo-cortical pathways, a differential effect on the low frequency VOR and an altered sensitivity to drugs in acute unilateral vestibulopathy.

Patterns of Eye Movement Impairment Correlate with Regional Brain Atrophy in Neurodegenerative Parkinsonism

BACKGROUND

One common feature of neurodegenerative parkinsonism including Parkinson's disease (PD), multisystem atrophy (MSA), and progressive supranuclear palsy (PSP) is altered eye movement control. Characteristic regional structural atrophy patterns in MRI can be observed in PD, MSA, and PSP.

OBJECTIVE

To investigate the association between eye movement disturbances and regional brain atrophy in patients with PD, MSA, and PSP.

METHODS

High-resolution 3-dimensional T1-weighted MRI images and video-oculographic recordings (EyeLink®) were obtained from 39 PD, 32 PSP, and 18 MSA patients and 24 matched healthy control subjects. Automatic regional volumetric assessment was performed using atlas-based volumetry (ABV).

RESULTS

The prevalence of saccadic intrusions as a measure of inhibitory control was significantly increased in PD patients compared to controls (p < 0.001) and negatively correlated with whole brain volume, cerebral brain volume, and occipital lobe volume (p = 0.0057, p = 0.0049, and p = 0.0059, respectively; all p values are false discovery rate corrected). In MSA, smooth pursuit was disturbed by characteristic "catch-up" saccades (p < 0.001) and it was significantly correlated with cerebellar volume (p = 0.004) and pontine volume (p < 0.001). The hallmark of PSP was pathologically slowed vertical peak eye velocities (p < 0.001); the lower the peak eye velocity, the more marked midbrain atrophy (p = 0.007).

CONCLUSIONS

Foci of regional atrophy correlated with disease-specific eye movement alterations in all investigated parkinsonian syndromes. Oculomotor impairment in PD, predominantly the result of executive dysfunction, was linked to cerebral atrophy. Impairment in the corresponding oculomotor pathways was associated with atrophy of pontocerebellar oculomotor structures in MSA and midbrain atrophy in PSP.

A case of patulous Eustachian tube associated with dizziness induced by nasal respiration

OBJECTIVE

To determine the relationship between Eustachian tube function and inner ear function in patulous Eustachian tube (pET).

METHODS

We encountered a patient with pET accompanied by dizziness that was induced by nasal respiration. Eye movements were recorded using video-oculography, and Eustachian tube function was assessed using a Eustachian tube function analyzer. Horizontal and vertical components of pupil position were assessed to test fixation, positional, and positioning nystagmus. Impedance testing with a Eustachian tube function analyzer was performed to confirm tympanometry results. We recorded these outcomes until the patient's symptoms improved.

RESULTS

When pET improved, the patient's symptoms were alleviated.

CONCLUSION

The present pET patient had mild vestibular symptoms. Therefore, pET patients with dizziness might be misdiagnosed with, for example, superior semicircular canal dehiscence, psychogenic vertigo, or Ménière's disease. For patients with few clinical symptoms or laboratory findings, clinicians need to consider dizziness-induced pET as a possible diagnosis.

The second and third phases of caloric nystagmus

CONCLUSION

The second and third phases of caloric nystagmus occur at a high rate. We can explain this phenomenon based on the hydrostatic pressure theory involved in perilymph.

OBJECTIVES

To clarify the incidence of the second and third phases of caloric nystagmus, and to measure their intensity.

METHODS

The subjects were 12 healthy humans. The right ear was stimulated using iced water. The first phase of caloric nystagmus was recorded in a supine position. Immediately after the cessation of the first phase, each subject was repositioned to a prone position, and the second phase was recorded. Immediately after the halt of the second phase, each subject was repositioned to a supine position, and the third phase was recorded. Nystagmus was analyzed using three-dimensional video-oculography.

RESULTS

The mean value of maximum slow-phase velocity (MSV) of the first phase was 27.2°/s. All subjects revealed the second phase, and the direction was toward the right. The mean value of MSV was 7.2°/s. Nine subjects (75%) showed the third phase, and the direction was toward the left. The mean value of MSV was 2.7°/s.