Internuclear and supranuclear disorders of eye movements: clinical features and causes

Horizontal gaze palsy with ipsilateral esotropia with substituted convergence in a child with medulloblastoma

Introduction: Horizontal Gaze palsy with concurrent esotropia and substituted convergence is a rare clinical presentation. Methods: We report a case of a 6-year-old child being treated for pontine medulloblastoma who presented with bilateral abducens and bilateral facial nerve palsy. The patient progressed to develop right sided horizontal gaze palsy with bilateral abducens palsy and substituted convergence. In view of limited abduction in his right eye, a modified Nishida procedure was performed followed by botulinum toxin to the right medial rectus both of which failed in improving the ocular alignment. Subsequently, the patient underwent an asymmetric, bilateral recess-resect procedure. Results: The recess-resect procedure resulted in a correction of his compensatory face turn and ocular deviation with orthotropia in primary position and binocular single vision. Conclusion: This case report reiterates the importance of asymmetric recess-resect surgery rather than vertical rectus transposition surgery in such a case.

Evaluation of Accommodation Amplitude and Convergence Insufficiency in Patients with Multiple Sclerosis

Purpose

To evaluate the near reflex components, including accommodation, convergence, and binocular fusional vergences in patients with multiple sclerosis (MS).

Material-Method

MS patients under 35 years of age without visual evoked potential (VEP) abnormalities (MS Group) and age-matched healthy individuals of (Control Group) were included in the study. Fusional vergence amplitudes, the amplitude of accommodation (AA), stereopsis measurements, near-object fixation and near point of convergence (NPC) measurements, Convergence Insufficiency Symptoms Survey (CISS) results, and the presence of nystagmus were recorded retrospectively from the files of the cases. Statistical comparison was made between the groups.

Results

The mean age was 28.04 ± 3.7 years in the MS group (20 females, 4 males) and 27.16 ± 3.1 years in the control group (20 females, 5 males) (p = .763). There was no statistically significant difference between groups in stereopsis (p = .395), mean convergence (p = .666), and divergence amplitudes (p = .773) at a distance, and mean convergence and (p = .836) divergence amplitudes (p = .877) at near, and NPC measurements (p = .908). The mean AA was 5.31 ± 0.7 D in the MS group and 6.1 ± 0.8 D in the control group (p < .001). CISS results were lower in the control group (p < .001). In addition, gaze-evoked nystagmus was statistically significantly higher in the MS group (p < .001).

Conclusion

Compared to the healthy control group, MS patients under 35 who did not have optic neuritis had lower accommodation amplitude and more signs in favor of convergence insufficiency symptoms. In addition, gaze evoked nystagmus was observed at a higher rate in the MS group. These findings may guide us in understanding the asthenopia findings of MS patients without optic neuritis.

Correlation between clinical and neuropathological subtypes of progressive supranuclear palsy

INTRODUCTION

Progressive supranuclear palsy (PSP) is characterized by pathology prominently in the basal ganglia, the tegmentum of the brainstem, and the frontal cortex. However, pathology varies according to clinical features. This study aimed to statistically verify the correspondence between the clinical and pathological subtypes of PSP.

METHODS

We identified patients with a pathological diagnosis of PSP and classified the eight clinical subtypes of the Movement Disorders Society criteria for the clinical diagnosis of PSP (MDS-PSP criteria) into the Richardson, Akinesia, and Cognitive groups. We used anti-phosphorylated tau antibody immunostaining to semi-quantitatively evaluate neurofibrillary tangles (NFTs) and coiled bodies/threads (CB/Ths) in the globus pallidus, subthalamic nucleus, and midbrain tegmentum. In the frontal cortex, tufted astrocytes (TAs) and CB/Ths were assessed on a 3-point scale. We compared the pathology among the three groups, recorded the phenotypes ranked the second and lower in the multiple allocation extinction rule and examined whether the pathology changed depending on applying each phenotype.

RESULTS

The Richardson group exhibited severe NFTs and CB/Ths in the midbrain tegmentum. The Akinesia group showed severe NFTs in the globus pallidus. The Cognitive group had severe TAs and CB/Ths in the frontal cortex. TAs and CB/Ths in the frontal cortex correspond to behavioral variant frontotemporal dementia, and supranuclear vertical oculomotor palsy.

CONCLUSION

These clinical symptoms may reflect the distribution of tau pathologies in PSP.

A Cross-Sectional Study of Clinical Spectrum and Outcome of Pure Midbrain Strokes

BACKGROUND

Pure mesencephalic infarcts are uncommon, the main clinical manifestations being oculomotor signs and ataxia.

OBJECTIVES

Primary objective was to determine the incidence of pure midbrain strokes. We also evaluated the clinical spectrum, syndromes, arterial territories involved, risk factors, and outcome at 3 months.

SETTINGS AND DESIGN

This cross-sectional study was conducted at the Neurology department of a tertiary teaching hospital in Kerala.

METHODS AND MATERIAL

We recorded clinical examination and radiological details of all the patients who presented with isolated midbrain strokes from December 2014 to December 2019. The clinical spectrum and outcomes of the patients at 3 months were analyzed.

RESULTS

Of the 520 posterior circulation stroke patients, 48 (9.2%) had isolated mesencephalic infarcts. Clinical manifestations included gait ataxia in 40 patients (83.3%), third nerve palsy in 29 (60.41%), fourth nerve palsy in 4 (8.3%), internuclear ophtalmoplegia in 9 (18.8%), upgaze paresis in 3 (6.3%), hemiparesis in 4 (8.3%), and cheiro-oral paraesthesia in 4 (8.3%). Of the 48 patients, 21 (43.8%) had Claude syndrome, 9 (18.8%) had Wernekink commisure syndrome, 6 (12.5%) had ataxic hemiparesis, 3 (6.3%) had Parinaud syndrome, 3 (6.3%) had Weber syndrome, 4 (8.3%) had Nothnagel syndrome, and 1 patient had a pure sensory stroke (2.1%). The anteromedial territory was frequently affected, in 37 (77%), characterized by oculomotor manifestations and ataxia. Posterior lesions were noted in three (6.3%), anterolateral lesions in three (6.3%), and lateral lesion in one (2.1%) patient. Combined lesions in posterior and paramedian territory were seen in four (8.3%). At the end of 3 months, 30 patients (62.5%) had a modified Rankin score of one.

CONCLUSIONS

Our study provides the incidence of midbrain stroke over 5 years. It also highlights the heterogeneity of clinical features of pure midbrain infarcts.

Detecting Abnormal Eye Movements in Patients with Neurodegenerative Diseases - Current Insights

This review delineates the ocular motor disturbances across a spectrum of neurodegenerative disorders, including Alzheimer's Disease (AD) and related disorders (ADRD), Parkinson's Disease (PD), atypical parkinsonism, and others, leveraging advancements in eye-tracking technology for enhanced diagnostic precision. We delve into the different classes of eye movements, their clinical assessment, and specific abnormalities manifesting in these diseases, highlighting the nuanced differences and shared patterns. For instance, AD and ADRD are characterized by increased saccadic latencies and instability in fixation, while PD features saccadic hypometria and mild smooth pursuit impairments. Atypical parkinsonism, notably Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS), presents with distinct ocular motor signatures such as vertical supranuclear gaze palsy and saccadic apraxia, respectively. Our review underscores the diagnostic value of eye movement analysis in differentiating between these disorders and also posits the existence of underlying common pathological mechanisms. We discuss how eye movements have potential as biomarkers for neurodegenerative diseases but also some of the existing limitations.

A case of bilateral horizontal gaze palsy and concurrent esotropia

Purpose

To report a unique case of bilateral horizontal pontine gaze palsy with concurrent esotropia, surgical management, and post-operative follow-up.

Observations

A 39-year-old male presented with diplopia and a history of neurocysticercosis. He was found to have bilateral horizontal gaze palsy and concurrent esotropia, R > L. Classic bimedial rectus recess-resect surgery was done to include resection of the right lateral rectus muscle. Follow-up three months post-op demonstrates markedly improved diplopia.

Conclusion and importance

We present a recommended therapeutic approach for the rare case of concurrent bilateral horizontal gaze palsy and esotropia, which should be further evaluated in longitudinal studies.

Contraversive Ocular Tilt Reaction with Contralesional Pseudo-Abducens Palsy in a Patient with Thalamomesencephalic Stroke

We report a patient presenting with unique neuroophthalmological features of contraversive ocular tilt reaction and concomitant contralesional pseudo-abducens palsy. Magnetic resonance imaging confirmed the presence of an acute infarct in the right thalamomesencephalic region. We discuss the clinical topography of these unique neuroophthalmological findings.

Greater Disability Is Associated with Worse Vestibular and Compensatory Oculomotor Functions in People Living with Multiple Sclerosis

Globally, there are nearly three million people living with multiple sclerosis (PLW-MS). Many PLW-MS experience vertigo and have signs of vestibular dysfunction, e.g., low vestibulo-ocular reflex (VOR) gains or the presence of compensatory saccades (CSs), on video head impulse testing (vHIT). We examined whether the vestibular function and compensatory oculomotor behaviors in PLW-MS differed based on the level of MS-related disability. The VOR gain, CS frequency and latency, and gaze position error (GPE) were calculated from the individual traces obtained during six-canal vHIT for 37 PLW-MS (mean age 53.4 ± 12.4 years-old, 28 females) with vertigo and/or an imbalance. The subjects were grouped by their Expanded Disability Status Scale (EDSS) scores: PLW-min-MS (EDSS = 1.0-2.5, n = 8), PLW-mild-MS (EDSS = 3.0-4.5, n = 23), and PLW-moderate-MS (EDSS = 5.0-6.0, n = 6). The between-group differences were assessed with Kruskal-Wallis tests. The VOR gains for most of the canals were higher for PLW-min-MS compared to PLW-mild- and mod-MS, respectively. CS occurred less often in PLW-min-MS versus PLW-mild- and mod-MS, respectively. No clear trend in CS latency was found. The GPE was often lower for PLW-min-MS compared to PLW-mild- and mod-MS, respectively. Thus, our data demonstrate that worse VOR and compensatory oculomotor functions are associated with a greater MS-related disability. PLW-MS may benefit from personalized vestibular physical therapy.

A case of horizontal gaze palsy with progressive scoliosis

Horizontal gaze palsy with progressive scoliosis is a rare entity with few cases in the literature. Despite the fact the patient will not present with typical symptoms of this syndrome, clinical suspicion should be raised particularly in terms of imaging findings. Imaging findings are characteristic to flag the possibility of this syndrome. Keeping in mind such congenital abnormalities on magnetic resonance imaging particularly for radiologists might help in the management process. Multidisciplinary teams play a crucial role in terms of communication to find the clinical, radiological and genetic studies to reach the diagnosis.

Diffusion tractography of superior cerebellar peduncle and dentatorubrothalamic tracts in two autopsy confirmed progressive supranuclear palsy variants: Richardson syndrome and the speech-language variant

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Different changes in DTI metrics in SCP and DRTT can be seen across PSP subtypes.

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DRTT tractography reconstructions demonstrated specific changes in PSP-RS.

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DTI and clinical PSP scores are specifically linked across each PSP variant.

Background

Progressive supranuclear palsy (PSP) is a 4-repeat tauopathy with neurodegeneration typically observed in the superior cerebellar peduncle (SCP) and dentatorubrothalamic tracts (DRTT). However, it is unclear how these tracts are differentially affected in different clinical variants of PSP.

Objectives

To determine whether diffusion tractography of the SCP and DRTT can differentiate autopsy-confirmed PSP with Richardson’s syndrome (PSP-RS) and PSP with predominant speech/language disorder (PSP-SL).

Methods

We studied 22 autopsy-confirmed PSP patients that included 12 with PSP-RS and 10 with PSP-SL. We compared these two groups to 11 patients with autopsy-confirmed Alzheimer’s disease with SL problems, i.e., logopenic progressive aphasia (AD-LPA) (disease controls) and 10 healthy controls. Whole brain tractography was performed to identify the SCP and DRTT, as well as the frontal aslant tract and superior longitudinal fasciculus. We assessed fractional anisotropy and mean diffusivity for each tract. Hierarchical linear modeling was used for statistical comparisons, and correlations were assessed with clinical disease severity, ocular motor impairment, and parkinsonism. DRTT connectomics matrix analysis was also performed across groups.

Results

The SCP showed decreased fractional anisotropy for PSP-RS and PSP-SL and increased mean diffusivity in PSP-RS, compared to controls and AD-LPA. Right DRTT fibers showed lower fractional anisotropy in PSP-RS and PSP-SL compared to controls and AD-LPA, with PSP-RS also showing lower values compared to PSP-SL. Reductions in connectivity were observed in infratentorial DRTT regions in PSP-RS vs cortical regions in PSP-SL. PSP-SL showed greater abnormalities in the frontal aslant tract and superior longitudinal fasciculus compared to controls, PSP-RS, and AD-LPA. Significant correlations were observed between ocular motor impairment and SCP in PSP-RS (p = 0.042), and DRTT in PSP-SL (p = 0.022). In PSP-SL, the PSP Rating Scale correlated with the SCP (p = 0.045) and DRTT (p = 0.008), and the Unified Parkinson’s Disease Rating Scale correlated with the DRTT (p = 0.014).

Conclusions

Degeneration of the SCP and DRTT are diagnostic features of both PSP-RS and PSP-SL and associations with clinical metrics validate the role of these tracts in PSP-related clinical features, particularly in PSP-SL.

Ocular Asymmetry in Electrooculographic Responses

Between the cornea and the posterior pole of the eye, there is a transepithelial potential capable of being registered through an electrooculogram (EOG). It is questionable whether electrooculographic responses are similar in both eyes despite ocular dominance in human beings. We studied the effect of different electrooculographic stimulation parameters, in terms of directionality, linear and angular velocity, contrast, and state of adaptation to light/dark, that may induce possible interocular differences in visual function. The study was carried out with electroencephalography-type surface electrodes placed in the medial, lateral, superior, and inferior positions of both human eyes to record the eye movements. We found a greater amplitude of the EOG response in the left eye than to the right eye for light bars moving from right to left (p < 0.01; t-test). The EOG response amplitude was similar in both eyes for light bars moving in vertical directions, but greater than horizontal or rotational stimuli. We conclude that vertical stimuli should be used for EOG functional evaluation of eye movements, since horizontal stimuli generate significant interocular differences.

Eye motor manifestations in children with neurometabolic disorders

Neurometabolic diseases are complex group of rare neurogenetic disorders, which are difficult to diagnose. Patients may have toxic metabolite accumulation, inadequate energy supply, or neurotransmitter deficiency, resulting in a variety of clinical manifestations and severity with enzyme activity or transporter function defects. Multiple organ involvement is frequently seen, among which neurological symptoms and signs are one of the most encountered problems. Ocular motor problems deserve special attention for it occurs in some inborn error of metabolism. Furthermore, some are early signs or characteristic findings of certain diseases, such as the gaze palsy in Niemann-Pick disease type C and Gaucher disease or oculogyric crisis in neurotransmitter diseases. Early recognition and intervention are important for better prognosis in treatable neurometabolic disorders. In addition, ways to evaluate and describe eye movement problems also help to demonstrate the severity or clinical progression for those diagnosed with certain neurometabolic diseases. However, the complexity of eye movement and ocular motor control renders our clinical observation, recording and even anatomic localization of abnormal eye movements. Clinicians are more likely to detect early signs and unravel problems by gaining awareness of abnormal eye movement. This study amied to approach neurometabolic diseases in children via eye motor manifestations.

MRI topography of lesions related to internuclear ophthalmoplegia in patients with multiple sclerosis or ischemic stroke

BACKGROUND AND PURPOSE

Internuclear ophthalmoplegia is a dysfunction of conjugate eye movements, caused by lesions affecting the medial longitudinal fasciculus (MLF). Multiple sclerosis (MS) and ischemic stroke represent the most common pathophysiologies. While magnetic resonance imaging (MRI) allows for localizing lesions affecting the MLF, comprehensive comparative studies exploring potential different spatial characteristics of lesions affecting the MLF are missing until now.

METHODS

We retrospectively investigated MRI examinations of 82 patients (40 patients with MS and 42 patients with ischemic stroke). For lesion localization, the brainstem was segmented into (1) ponto-medullary junction, (2) mid pons, (3) upper pons, and (4) mesencephalon.

RESULTS

Corresponding lesions affecting the MLF were observed in 29/40 (72.5%) MS and 38/42 (90.5%) stroke patients. Compared to stroke patients, MS patients had significantly more lesions in multiple locations (P < .001). Stroke patients showed more lesions at the level of the mesencephalon (P < .001), while lesions at the level of the ponto-medullary junction, mid, and upper pons did not statistically differ between the groups.

CONCLUSION

Our results demonstrate that multiple lesions affecting the MLF make inflammatory-demyelination due to MS more likely, while lesion localization at the level of the mesencephalon favors ischemia.

Binocular Vision in Patients with Multiple Sclerosis

PURPOSE

Oculomotor disorders have been reported in multiple sclerosis (MS) in up to 80% of cases. There have been studies evaluating binocular vision in several neurological diseases, but not in MS. Considering that a high percentage of eye-movement anomalies have been reported, the aim of this study was to analyze binocular vision in these subjects.

METHODS

A total of 59 participants with MS - 21 with monocular optic neuritis, eleven with binocular optic neuritis, and 27 without optic neuritis - and 26 age-matched controls were enrolled. Binocular vision was analyzed using near point of convergence (NPC), positive and negative fusional vergence for far and near distance, measurement of heterophoria at both distances with cover and modified Thorington tests, and random-dot stereoscopy.

RESULTS

The percentage of subjects with abnormal NPC values was highest in the MS group, followed by the MSONm (MS with optic neuritis in one eye), MSONb (MS with optic neuritis in both eyes), and control groups. MS patients showed an esophoric trend at near distance. Positive fusional vergence showed no significant differences between control and MS groups, but higher variability in recovery was found in MS groups. Negative fusional vergence at near distance showed significant differences between the control group and the two MS groups, with optic neuritis for both break-point and recovery values. A high percentage of patients with MS had alterations on stereopsis.

CONCLUSION

Alterations in binocular vision were present in MS, with divergence at near distance and stereopsis the most affected parameters. Likewise, MS patients with optic neuritis showed worse binocular vision.

Current landscape in motoneuron regeneration and reconstruction for motor cranial nerve injuries

The intricate anatomy and physiology of cranial nerves have inspired clinicians and scientists to study their roles in the nervous system. Damage to motor cranial nerves may result from a variety of organic or iatrogenic insults and causes devastating functional impairment and disfigurement. Surgical innovations directed towards restoring function to injured motor cranial nerves and their associated organs have evolved to include nerve repair, grafting, substitution, and muscle transposition. In parallel with this progress, research on tissue-engineered constructs, development of bioelectrical interfaces, and modulation of the regenerative milieu through cellular, immunomodulatory, or neurotrophic mechanisms has proliferated to enhance the available repertoire of clinically applicable reconstructive options. Despite these advances, patients continue to suffer from functional limitations relating to inadequate cranial nerve regeneration, aberrant reinnervation, or incomplete recovery of neuromuscular function. These shortfalls have profound quality of life ramifications and provide an impetus to further elucidate mechanisms underlying cranial nerve denervation and to improve repair. In this review, we summarize the literature on reconstruction and regeneration of motor cranial nerves following various injury patterns. We focus on seven cranial nerves with predominantly efferent functions and highlight shared patterns of injuries and clinical manifestations. We also present an overview of the existing reconstructive approaches, from facial reanimation, laryngeal reinnervation, to variations of interposition nerve grafts for reconstruction. We discuss ongoing endeavors to promote nerve regeneration and to suppress aberrant reinnervation and the development of synkinesis. Insights from these studies will shed light on recent progress and new horizons in understanding the biomechanics of peripheral nerve neurobiology, with emphasis on promising strategies for optimizing neural regeneration and identifying future directions in the field of motor cranial neuron research.

Case Report: Bilateral Horizontal Gaze Palsy (1 + 1 Syndrome): A Supranuclear Gaze Palsy

SIGNIFICANCE

A rare case of bilateral horizontal gaze palsy with intact vertical gaze eye movements and largely intact vestibulo-ocular reflex is presented owing to demyelinating lesions of the patient's bilateral paramedian pontine reticular formations and left infranuclear abducens nerve from the patient's recently diagnosed multiple sclerosis.

PURPOSE

The purpose of this study was to report on a rare case of bilateral horizontal gaze palsy from a supranuclear lesion in a patient with a recent diagnosis of multiple sclerosis.

CASE REPORT

A 43-year-old African American woman presented urgently for evaluation of her inability to move her eyes into either horizontal gaze. Vertical conjugate movements remained intact, as did three of four extraocular muscles with horizontal vestibulo-ocular reflex testing, suggesting a supranuclear palsy. Magnetic resonance imaging revealed two demyelinating lesions in her inferior pons, which spared her nuclear and internuclear horizontal gaze pathways, as well as three of four extraocular muscles of her infranuclear horizontal gaze pathway as evidenced by her largely intact vestibulo-ocular reflex. This suggested bilateral paramedian pontine reticular formation lesions (supranuclear) and a mild left abducens nerve palsy (infranuclear).

CONCLUSIONS

Close evaluation of extraocular motilities and a solid understanding of the supranuclear, nuclear, internuclear, and infranuclear components of the horizontal gaze pathway can help identify challenging gaze palsies when encountered in a clinical setting. Appropriate neuroimaging can then be performed with an emphasis on the suspected location of the lesion(s) based on the patient's clinical findings.

Anatomical structure responsible for direction changing bilateral gaze-evoked nystagmus in patients with unilateral cerebellar infarction

The direction-changing bilateral gaze-evoked nystagmus (GEN) (BGEN) is a more specific sign for a gaze-holding deficit than unilateral GEN (UGEN) in a central lesion. We sought to clarify which cerebellar structure is responsible for the generation of BGEN compared with UGEN.We studied 47 cases of UGEN or BGEN associated with isolated unilateral cerebellar infarction in the territories of the cerebellar arteries diagnosed by brain magnetic resonance image (MRI) from June 2007 to April 2014. To identify the structures involved in the generation of BGEN, the overlapped lesions of the BGEN group were subtracted from those of UGEN group and vice versa.About half of the patients (25/47, 53%) showed BGEN and others showed UGEN. There was no difference in the interval from symptom onset to examination between 2 groups (1.3 days vs 2.5 days, P = .24). Thirty-five patients (35/47, 75%) with GEN also showed spontaneous nystagmus. Lesion subtraction analyses revealed that both of the patients with BGEN and UGEN had damage around the vermal pyramid, the uvula and the tonsil, parts of the biventer lobule, and the inferior semilunar lobule.Midline and lower cerebellar structures are related to both BGEN and UGEN in patients with unilateral cerebellar infarction. Regardless of unilateral or bilateral, GEN may represent damage of the gaze-holding neural integrator control system in human.

Binocular, Accommodative and Oculomotor Alterations In Multiple Sclerosis: A Review

Multiple sclerosis (MS) is an acquired demyelinating and inflammatory neurodegenerative disease affecting the central nervous system (CNS). Clinical and subclinical ocular disturbances occur in almost all patients with MS. The objective of this narrative review was to collect and summarize the available scientific information on oculomotor, accommodative and binocular alterations that have been reported in MS. A systematic search strategy with the following descriptors was carried out: multiple sclerosis, ocular motility disorders, internuclear ophthalmoplegia, nystagmus, vergences, fixation, pupil reflex, accommodation and stereopsis. According to the search, some oculomotor alterations were found to be commonly reported in MS, such as alterations in saccades and nystagmus. In contrast, accommodative, vergence and stereopsis alterations have not been comprehensively studied despite their relevance, with only minimal evidence showing a potential negative impact of the disease on these aspects. In conclusion, oculomotor impairment is a common component of disability in MS patients and should be considered when managing this type of patients. More research is still needed to know the real impact of this disease on binocular vision and accommodation.

Neuro-Ophthalmology at the Bedside: A Clinical Guide

Neuro-ophthalmological signs and symptoms are common in the emergency department but are a frequent source of diagnostic uncertainties. However, neuro-ophthalmological signs often allow a precise neuro-topographical localization of the clinical problem. A practical concept is presented how to perform a neuro-ophthalmological examination at the bedside and to interpret key findings under the aspect of emergency medicine with limited resources.

Ocular manifestations in patients with cerebrovascular accidents in India: a cross-sectional observational study

PURPOSE

To assess ophthalmic manifestations in patients with stroke and emphasize the importance of a formal screening for visual problems in stroke patients in hospital and rehabilitation settings.

METHODS

This was a cross-sectional study of 50 newly diagnosed patients with stroke with Glasgow Coma Scale (GCS) > 8 examined within 3 days of onset. A detailed ophthalmic examination was performed for each patient including visual acuity, fields, ocular motility, slit lamp and fundus examination, line bisection tests and cranial nerve assessment. Radiological investigations were reviewed and anatomically correlated.

RESULTS

A total of 50 patients (41 male and nine female) were included in the study. Mean age of the stroke cohort was 51.36 years. Twenty-nine patients (58%) had a subcortical stroke, while 42% (n = 21) patients had a cortical stroke. Nineteen patients (38%) demonstrated visual field defects. Twenty-one patients (42%) had a gaze palsy. Vertical gaze palsy (n = 8) was more common in cortical stroke, while internuclear ophthalmoplegia (n = 2), horizontal gaze palsies (n = 4) and Parinaud's syndrome (n = 1) were seen more commonly in those with subcortical stroke. Twenty-four percent (n = 12) patients had nystagmus. Twelve percent (n = 6) patients had diplopia. Thirty-eight percent (n = 19) patients had convergence insufficiency. Sixteen patients (32%) complained of visual impairment. Retinal abnormalities were seen in 58% (n = 29) of patients.

CONCLUSIONS

Ophthalmic manifestations were seen in 90% of stroke survivors. Their presence in majority of the patients in our cohort suggests that earliest routine ophthalmic examination should be mandatory in all patients with acute stroke.

Conjugate eye deviation due to pontine infarction: Report of 2 cases

•We report 2 patients with pontine infarcts showing transient conjugate eye deviation.•Conjugate eye deviation resolved within a few days in both patients.•Small restricted dorsomedial pontine lesions can produce conjugate eye deviation.

Role of neural integrators in oculomotor systems: a systematic narrative literature review

PURPOSE

To evaluate the role of neural integrators (NI) in the oculomotor system.

METHODS

A literature search was carried out using several electronic databases during the months of June 2014 to March 2015. The following keywords were used to generate focused results: 'neural integrators', 'gaze-holding', 'oculomotor integration', 'impaired gaze-holding', 'gaze evoked nystagmus' and 'gaze dysfunction'. Further materials were found through searching relevant articles within reference lists. Seventy-one articles were sourced for this review which analysed animal and human subjects and network models; 45 were studies of humans, 16 studies of primates, three studies of felines and one study from rats and network models. The remaining articles were literature reviews.

RESULTS

The horizontal and vertical, including torsional, NI are located logically in the brainstem, nearby their appropriate target extraocular motoneuron nuclei for stable eye position in eccentric position. The nucleus prepositus hypoglossi (NPH) and medial vestibular nuclei (MVN) are closely linked at the caudal pons and dorsal rostral medulla, integrating horizontal conjugate eye movement. The interstitial nucleus of Cajal (INC) integrates vertical and torsional eye movement at the upper midbrain. The integrator time constant is averaged to 25 seconds in human horizontal and animal vertical NI to perform its function. Case reports revealed that dysfunction of horizontal NI also resulted in vertical ocular deviations, indicating some overlap of horizontal and vertical gaze control. Furthermore, pharmacological inactivation of NI exposed a population of inhibitory neurotransmitters that permits its mechanism of action; allowing for smooth conjugate movement.

CONCLUSIONS

Neural integrators operate to integrate eye velocity and eye position information to provide signals to extraocular motoneurons to attain and maintain a new position. Therefore, NI allow image stabilization during horizontal and vertical eye movements at eccentric positions for comfortable single vision.

Case report of a patient with 'one-and-a-half plus syndrome: nine syndrome'

This case talks about ‘One-and-a-half plus syndrome’, a clinical syndrome affecting binocular vision and facial nerve. One-and-a-half plus syndrome is a less known clinical syndrome which constitutes of a conjugate horizontal gaze palsy in one direction and an internuclear ophthalmoplegia in the other direction. Despite the known association between ischemia, autoimmune disorders, multiple sclerosis, with mono neuritis multiplex resulting in extra ocular movement disorder, one-and-a-half plus syndrome is rarely considered in the differential diagnosis of eye ball movement disorders, as many clinicians are not able to diagnose such a case as ‘ the eyes don’t see what the mind doesn’t know’. Our report aims to raise awareness about connective tissue disorders presenting as neuro-ophthalmological syndrome, as early recognition can accelerate diagnosis and decrease the morbidity.

Isolated medial longitudinal fasciculus syndrome: Review of imaging, anatomy, pathophysiology and differential diagnosis

Isolated medial longitudinal fasciculus (MLF) syndrome due to infarction limited only to the midbrain is a rare occurrence. The MLF are a group of fiber tracts located in the paramedian area of the midbrain and pons. They control horizontal eye movements by interconnecting oculomotor and abducens nuclei in the brain stem. Such small infarcts can easily be overlooked by young neuroradiologists and trainees. In this review, we discuss the clinical and imaging characteristics, comprehensive review of the anatomy, pathophysiology, and differential diagnosis.

Surgical planning and innervation in pontine gaze palsy with ipsilateral esotropia

PURPOSE

To discuss surgical intervention strategies among patients with horizontal gaze palsy with concurrent esotropia.

METHODS

Five consecutive patients with dorsal pontine lesions are presented. Each patient had horizontal gaze palsy with symptomatic diplopia as a consequence of esotropia in primary gaze and an anomalous head turn to attain single binocular vision.

RESULTS

Clinical findings in the first 2 patients led us to presume there was complete loss of rectus muscle function from rectus muscle palsy. Based on this assumption, medial rectus recessions with simultaneous partial vertical muscle transposition (VRT) on the ipsilateral eye of the gaze palsy and recession-resection surgery on the contralateral eye were performed, resulting in significant motility limitation. Sequential recession-resection surgery without simultaneous VRT on the 3rd patient created an unexpected motility improvement to the side of gaze palsy, an observation differentiating rectus muscle palsy from paresis. Recession combined with VRT approach in the esotropic eye was abandoned on subsequent patients. Simultaneous recession-resection surgery without VRT in the next 2 patients resulted in alleviation of head postures, resolution of esotropia, and also substantial motility improvements to the ipsilateral hemifield of gaze palsy without limitations in adduction and vertical deviations.

CONCLUSIONS

Ocular misalignment and abnormal head posture as a result of conjugate gaze palsy can be successfully treated by basic recession-resection surgery, with the advantage of increasing versions to the ipsilateral side of the gaze palsy. Improved motility after surgery presumably represents paresis, not "paralysis," with residual innervation in rectus muscles.

Paroxysmal tonic upward gaze as a presentation of de-novo mutations in CACNA1A

OBJECTIVE

Paroxysmal tonic upward gaze was initially described as a benign phenomenon with negative investigations and eventual complete resolution of symptoms. Later publications demonstrated that a similar clinical picture may arise from structural brain lesions, channelopathies, neurotransmitter disorders, and epileptic seizures. CACNA1A related disorders manifest as a wide spectrum of paroxysmal neurological disorders: episodic ataxia 2, hemiplegic migraine, benign paroxysmal torticollis of infancy, and paroxysmal vertigo. Paroxysmal tonic upward gaze as a phenomenon in patients with mutations in the CACNA1A gene has only been reported once.

METHODS

We describe three patients with multiple episodes of paroxysmal tonic upward gaze that appeared during the first months of life. In addition the patients demonstrated motor and language delay and cerebellar ataxia. A sequence analysis of the CACNA1A gene in one patient and whole exome sequencing in the other patients were performed.

RESULTS

Sequence analysis of the CACNA1A gene in one patient and whole exome sequencing in the two other patients revealed 3 different de-novo mutations in the CACNA1A gene.

CONCLUSION

CACNA1A mutations should be evaluated in infants and young children with paroxysmal tonic upgaze especially if associated with developmental delay, cerebellar signs, and other types of paroxysmal event.

Symptomatic treatment and management of multiple sclerosis

The range of symptoms which occur in multiple sclerosis (MS) can have disabling functional consequences for patients and lead to significant reductions in their quality of life. MS symptoms can also interact with each other, making their management challenging. Clinical trials aimed at identifying symptomatic therapies have generally been poorly designed and have tended to be underpowered. Therefore, the evidence base for the management of MS symptoms with pharmacologic therapies is not strong and tends to rely upon open-label studies, case reports, and clinical trials with small numbers of patients and poorly validated clinical outcome measures. Recently, there has been a growing interest in the management of MS symptoms with pharmacologic treatments, and better-designed, randomized, double-blind, controlled trials have been reported. This chapter will describe the evidence base predominantly behind the various pharmacologic approaches to the management of MS symptoms, which in most, if not all, cases, requires multidisciplinary input. Drugs routinely recommended for individual symptoms and new therapies, which are currently in the development pipeline, will be reviewed. More interventional therapies related to symptoms that are refractory to pharmacotherapy will also be discussed, where relevant.

Beyond the cover test: the motor half of the sensorimotor exam

The cover tests fulfill both the "sensory" and the "motor" requirements of the sensorimotor exam because they not only detect and quantify strabismus but also evaluate control. Control is achieved through various types of vergence, but vergence is not the only type of eye movement that is integral to fusion. The function of all eye movements is to position and maintain similar images on corresponding areas of the retinae in order to sustain binocular vision. Therefore, a complete motor exam should include evaluation of all eye movement systems. Such an exam can be performed without expensive and complicated equipment, without supplementary education, without significantly extending exam time, and within the confines of an average exam lane, because much of the exam is concealed within the standard sensorimotor evaluation. The term "sensorimotor exam" underscores the fact that sensory and motor fusion, and their respective cortical pathways, are inextricably linked, and function simultaneously and cooperatively to achieve normal visual experience.

Profile of Gaze Dysfunction following Cerebrovascular Accident

Aim. To evaluate the profile of ocular gaze abnormalities occurring following stroke. Methods. Prospective multicentre cohort trial. Standardised referral and investigation protocol including assessment of visual acuity, ocular alignment and motility, visual field, and visual perception. Results. 915 patients recruited: mean age 69.18 years (SD 14.19). 498 patients (54%) were diagnosed with ocular motility abnormalities. 207 patients had gaze abnormalities including impaired gaze holding (46), complete gaze palsy (23), horizontal gaze palsy (16), vertical gaze palsy (17), Parinaud's syndrome (8), INO (20), one and half syndrome (3), saccadic palsy (28), and smooth pursuit palsy (46). These were isolated impairments in 50% of cases and in association with other ocular abnormalities in 50% including impaired convergence, nystagmus, and lid or pupil abnormalities. Areas of brain stroke were frequently the cerebellum, brainstem, and diencephalic areas. Strokes causing gaze dysfunction also involved cortical areas including occipital, parietal, and temporal lobes. Symptoms of diplopia and blurred vision were present in 35%. 37 patients were discharged, 29 referred, and 141 offered review appointments. 107 reviewed patients showed full recovery (4%), partial improvement (66%), and static gaze dysfunction (30%). Conclusions. Gaze dysfunction is common following stroke. Approximately one-third of patients complain of visual symptoms, two thirds show some improvement in ocular motility.

Brainstem pathways for horizontal eye movement: pathologic correlation with MR imaging

Horizontal eye movements are conducted by the medial rectus and the lateral rectus muscles, which are innervated by the oculomotor nerve (cranial nerve III) and the abducens nerve (cranial nerve VI), respectively. The oculomotor and the abducens nuclei are interconnected by a tract in the brainstem named the medial longitudinal fasciculus (MLF). Through the MLF, the actions of the oculomotor and the abducens nuclei are coordinated, generating conjugate horizontal eye movements. The disorders of horizontal eye movement that are caused by brainstem lesions are classified into three groups: (a) lateral gaze palsy, (b) internuclear ophthalmoplegia, and (c) one-and-a-half syndrome. Lateral gaze palsy is caused by a lesion involving the paramedian pontine reticular formation (PPRF) or the abducens nucleus. Internuclear ophthalmoplegia occurs as a result of a lesion involving the MLF. One-and-a-half syndrome is a combination of lateral gaze palsy and internuclear ophthalmoplegia and is caused by a lesion involving both (a) the ipsilateral PPRF or the ipsilateral abducens nucleus and (b) the ipsilateral MLF. The pathologic lesions depicted on magnetic resonance images were topographically well correlated with the brainstem pathways and each type of horizontal eye movement disorder. Most of the lesions were tiny acute infarctions and were found in the most posterior region of the pons, which corresponded to the location of the brainstem pathways. Therefore, awareness of the brainstem pathways controlling horizontal eye movement is important to avoid missing a small pontine lesion.

Disease and patient characteristics in NP-C patients: findings from an international disease registry

BACKGROUND

Niemann-Pick disease type C (NP-C) is a rare neurovisceral disease characterized by progressive neurodegeneration and premature death. We report data recorded at enrolment in an ongoing international NP-C registry initiated in September 2009 to describe disease natural history, clinical course and treatment experience of NP-C patients in clinical practice settings.

METHODS

The NPC Registry is a prospective observational cohort study. Participating sites are encouraged to evaluate all consecutive patients with a confirmed diagnosis of NP-C, regardless of their treatment status. All patients undergo clinical assessments and medical care as determined by their physicians. Data are collected through a secure internet-based data collection system.

RESULTS

As of 19th March, 2012, 163 patients have been enrolled in centres across 14 European countries, Australia, Brazil and Canada. The mean (SD) age at enrolment was 19.6 (13.0) years. In general there was a long lag time between the mean (SD) age at neurological onset (10.9 (9.8) years) and age at diagnosis (15.0 (12.2) years). Among all enrolled patients, 107 were diagnosed based on combined genetic testing and filipin staining. Sixteen (11%) out of 145 patients with available age-at-neurological-onset data had early-infantile neurological onset, 45 (31%) had late-infantile onset; 45 (31%) had juvenile onset and 39 (27%) had adolescent/adult onset. The frequencies of neonatal jaundice, hepatomegaly and/or splenomegaly during infancy were greatest among early-infantile patients, and decreased with increasing age at neurological onset. The most frequent neurological manifestations were: ataxia (70%), vertical supranuclear gaze palsy (VSGP; 70%), dysarthria (66%), cognitive impairment (62%), dysphagia (52%). There were no notable differences in composite NP-C disability scores between age-at-neurological-onset groups. Miglustat therapy at enrolment was recorded in 117/163 (72%) patients.

CONCLUSIONS

Approximately two-thirds of this NP-C cohort had infantile or juvenile onset of neurological manifestations, while the remaining third presented in adolescence or adulthood. While systemic symptoms were most common among patients with early-childhood onset disease, they were also common among patients with adolescent/adult onset. The profiles of neurological manifestations in this Registry were in line with previous publications.

The neuro-ophthalmology of multiple sclerosis

Multiple sclerosis (MS) is a disease marked by focal demyelinating inflammatory plaques throughout the CNS. Neuro-ophthalmologic sequelae are common in MS and may arise from the disease itself or from treatment of the disease. Both afferent and efferent functions may be affected. Despite much progress, our understanding of the pathophysiology of MS, and the efficacy of our available treatments, remain inadequate. Here, we review the chief neuro-ophthalmologic abnormalities associated with MS and discuss the emerging diagnostic and therapeutic advances that are likely to further our understanding of MS and its treatment.

Vertical supranuclear gaze palsy in Niemann-Pick type C disease

Vertical supranuclear gaze palsy (VSGP) is a key clinical feature in patients with Niemann-Pick type C disease (NP-C), a rare, autosomal recessive, neuro-visceral disorder caused by mutations in either the NPC1 or NPC2 gene. VSGP is present in approximately 65 % of the cases and is, with gelastic cataplexy, an important risk indicator for NP-C. VSGP in NP-C is characterized by a paralysis of vertical saccades, especially downward, with the slow vertical eye movement systems (smooth pursuit and the vestibulo-ocular reflex) spared in the early phase of the disease. This dissociation is caused by a selective vulnerability of the neurons in the rostral interstitial nuclei of the medial longitudinal fasciculus (riMLF) in NP-C. Here we discuss VSGP in NP-C and how clinicians can best elicit this sign.

The nucleus pararaphales in the human, chimpanzee, and macaque monkey

The human cerebral cortex and cerebellum are greatly expanded compared to those of other mammals, including the great apes. This expansion is reflected in differences in the size and organization of precerebellar brainstem structures, such as the inferior olive. In addition, there are cell groups unique to the human brainstem. One such group may be the nucleus pararaphales (PRa); however, there is disagreement among authors about the size and location of this nucleus in the human brainstem. The name "pararaphales" has also been used for neurons in the medulla shown to project to the flocculus in the macaque monkey. We have re-examined the existence and status of the PRa in eight humans, three chimpanzees, and four macaque monkeys using Nissl-stained sections as well as immunohistochemistry. In the human we found a cell group along the midline of the medulla in all cases; it had the form of interrupted cell columns and was variable among cases in rostrocaudal and dorsoventral extent. Cells and processes were highly immunoreactive for non-phosphorylated neurofilament protein (NPNFP); somata were immunoreactive to the synthetic enzyme for nitric oxide, nitric oxide synthase, and for calretinin. In macaque monkey, there was a much smaller oval cell group with NPNFP immunoreactivity. In the chimpanzee, we found a region of NPNFP-immunoreactive cells and fibers similar to what was observed in macaques. These results suggest that the "PRa" in the human may not be the same structure as the flocculus-projecting cell group described in the macaque. The PRa, like the arcuate nucleus, therefore may be unique to humans.

Celsr3 is required for normal development of GABA circuits in the inner retina

The identity of the specific molecules required for the process of retinal circuitry formation is largely unknown. Here we report a newly identified zebrafish mutant in which the absence of the atypical cadherin, Celsr3, leads to a specific defect in the development of GABAergic signaling in the inner retina. This mutant lacks an optokinetic response (OKR), the ability to visually track rotating illuminated stripes, and develops a super-normal b-wave in the electroretinogram (ERG). We find that celsr3 mRNA is abundant in the amacrine and ganglion cells of the retina, however its loss does not affect synaptic lamination within the inner plexiform layer (IPL) or amacrine cell number. We localize the ERG defect pharmacologically to a late-stage disruption in GABAergic modulation of ON-bipolar cell pathway and find that the DNQX-sensitive fast b1 component of the ERG is specifically affected in this mutant. Consistently, we find an increase in GABA receptors on mutant ON-bipolar terminals, providing a direct link between the observed physiological changes and alterations in GABA signaling components. Finally, using blastula transplantation, we show that the lack of an OKR is due, at least partially, to Celsr3-mediated defects within the brain. These findings support the previously postulated inner retina origin for the b1 component and reveal a new role for Celsr3 in the normal development of ON visual pathway circuitry in the inner retina.

Visual information is transmitted through the retina from photoreceptors to bipolars to ganglion cells, the output neurons connecting to the brain. This vertical transmission of information is modulated by inhibitory lateral interneurons. Normal vision requires the proper transmission and processing of these neuronal signals. In the inner retina, amacrine cells are the main class of inhibitory interneurons. They modulate the information from bipolar to ganglion cells and are functionally responsible for adjusting image brightness and for detecting motion. Physiological studies have revealed important aspects of the mechanisms of inhibitory modulation, and anatomical studies have identified the many amacrine subclasses and their non-random arrangement within the retina. Although cell–cell interactions are thought to be critical for establishing the important physiological and morphological features of this cell class, the precise molecules and their functions are mostly unknown. In this paper we report the discovery of a mutant that identifies the atypical cell adhesion molecule, Celsr3, as critical for proper development of GABA-signaling pathways in the inner retina.

Ophthalmologic manifestations commonly misdiagnosed as demyelinating events in multiple sclerosis patients

PURPOSE OF REVIEW

Multiple sclerosis may affect both afferent and efferent visual pathways, and sometimes physicians err on ordinary ophthalmologic diagnosis due to overlapping symptoms between demyelinating and nondemyelinating visual diseases. The present article highlights nondemyelinating ocular occurrences due to physiologic or other pathologic processes that may appear in some patients.

RECENT FINDINGS

Optic neuritis is representative of the most common and best-studied demyelinating visual occurrence in multiple sclerosis. However, other nondemyelinating visual disturbances also seen in the general population may be erroneously interpreted as being part of the underlying disease. This comparison has not been documented and may be helpful to overcome such difficulties.

SUMMARY

Based on clinical history and some strategies of ophthalmologic examination, physicians can achieve the correct diagnosis. Some clinical situations, however, may be challenging and a multidisciplinary approach in the care of multiple sclerosis is warranted.