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Riassunto La vertigine e un sintomo molto frequente, che, il piu delle volte, rivela una patologia “benigna” come una neuronite vestibolare, una malattia di Meniere, un’emicrania vestibolare, una vertigine parossistica posizionale benigna o un processo funzionale. Tuttavia, puo rivelare una patologia neurologica grave, il piu delle volte vascolare. Oltre alla definizione della vertigine, il colloquio con il paziente permette di classificarla all’interno di un quadro nosologico molto preciso a seconda della durata, della recidiva e della modalita di scatenamento: vertigine duratura (> 24 h), vertigini spontanee ricorrenti, vertigini parossistiche posizionali, vertigini brevi e molto frequenti, instabilita posturale. L’esame clinico e essenziale e, talvolta, superiore alla risonanza magnetica, in particolare la ricerca e la descrizione di un nistagmo, le manovre dell’Head Impulse Test, dell’Head Shaking Test e di Dix e Hallpike e la ricerca di una skew deviation.

International audience; Background: Outcomes of coronavirus disease 2019 (COVID-19) in patients with neuromyelitis optica spectrum disorders (NMOSD) or myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), often treated with immunosuppressive therapies, are still unknown.Methods: We conducted a multicenter, retrospective, observational cohort study among all French expert centers for neuromyelitis optica and related disorders. Patients with NMOSD or MOGAD included in the study received a confirmed or highly suspected diagnosis of COVID-19 between 1 March 2020 and 30 June 2020. Main outcome was COVID-19 severity score assessed on a seven-point ordinal scale ranging from 1 (not hospitalized with no limitations on activities) to 7 (death).Results: Fifteen cases (mean [SD] age: 39.3 [14.3] years, 11 female) were included. Five patients (33.3%) were hospitalized, all receiving rituximab. A 24-year-old patient with positive aquaporine-4 antibody, with obesity as comorbidity, needed mechanical ventilation. Outpatients were receiving anti-CD20 (5), mycophenolate mofetil (3) or azathioprine (3). They were younger (mean [SD] age: 37.0 [13.4] years), with a longer disease duration (mean [SD]: 8.3 [6.3] years) and had a lower expanded disability severity score (EDSS) score (median [range] EDSS: 2.5 [0-4]) relative to patients requiring hospitalization (mean [SD] age: 44.0 [16.4] years, mean [SD] disease duration: 5.8 [5.5] years, median [range] EDSS: 4 [0-6.5]).Conclusions: COVID-19 outcome was overall favorable in this cohort. Larger international studies are needed to identify risk factors of severe COVID-19; however, we recommend personal protective measures to reduce risk of SARS-CoV-2 infection in this immunocompromised population.

Resume Le vertige est un symptome tres frequent revelant le plus souvent une pathologie « benigne » comme une neuronite vestibulaire, une maladie de Meniere, une migraine vestibulaire, un vertige paroxystique positionnel benin ou un processus fonctionnel. Mais il peut reveler une pathologie neurologique grave, le plus souvent vasculaire. Outre la definition du vertige, l’entretien avec le patient permet de le classer dans un cadre nosologique assez precis en fonction de la duree, de la recurrence et du mode de declenchement : le vertige durable (> 24 h), les vertiges spontanes recurrents, les vertiges paroxystiques positionnels, les vertiges brefs et tres frequents, l’instabilite posturale. L’examen clinique est essentiel notamment la recherche et la description d’un nystagmus, les manœuvres du Head Impulse Test, du Head Shaking Test, de Dix et Hallpike et la recherche d’une skew deviation.

BACKGROUND/OBJECTIVE Performances on spatial decision eye-tracking tasks are known to be impaired in patients with moderate Alzheimer's disease (AD), but the clinical relevance of this deficit during earlier stages of AD remains unclear. METHODS This study recruited patients with amnestic mild cognitive impairment (aMCI, prodromal AD), patients with mild AD, and age-matched controls from three French memory clinics. Participants' ability to make spatial judgments and decisions was assessed with an eye-tracking system, and cognitive performance on conventional neuropsychological tests was evaluated. RESULTS We enrolled 26 controls, 25 aMCI patients (median Mini-Mental State Exam [MMSE] 26), and 23 mild-AD patients (median MMSE 23). Patients with mild AD had higher error rates on the spatial decision task than aMCI patients and controls (32.4% versus 23.5%; p

Resume L’oscillopsie est la perception erronee d’une instabilite de la scene visuelle. L’oscillopsie resulte le plus souvent d’une instabilite oculaire, comme un nystagmus, un autre mouvement oculaire anormal ou une insuffisance du reflexe vestibulo-oculaire. Il s’agit d’un symptome invalidant et souvent associe a une degradation de l’acuite visuelle, observe dans differentes circonstances pathologiques en neurologie. Le but de cet article de synthese est de comprendre les mecanismes de stabilisation du regard, les differents mecanismes physiopathologiques pouvant conduire a une instabilite oculaire et a une oscillopsie et d’approcher les differentes prises en charge therapeutiques possibles.

Spontaneous eye movements during imagery are not random and can be used to study and reveal mental visualization processes (Fourtassi et al., 2013; Johansson et al. 2006). For example, we previously showed that during memory recall of French towns via imagery healthy individuals looks straight ahead when recalling Paris and their subsequent gaze positions are significantly correlated with the real GPS coordinates of the recalled towns. This correlation suggests that memory retrieval is done via depictive representations as it is never found when the towns are recalled using verbal fluency. In the present paper we added to this finding by showing that the mental image is spontaneously centered on the head or body midline. In order to investigate the capacities of visual imagery in patients, and by extension, the role of primary visual cortex and fronto-parietal cortex in spatial visual imagery, we recorded gaze positions during memory recall of French towns in an imagery task, a non-imagery task (verbal fluency), and a visually-guided task in five patients with left or right hemianopia and in four patients with hemineglect (two with left hemianopia and two without). The correlation between gaze position and real GPS coordinates of the recalled towns was significant in all hemianopic patients, but in patients with hemineglect this was only the case for towns located on the right half of the map of France. This suggests hemianopic patients can perform spatially consistent mental imagery despite direct or indirect unilateral lesions of the primary visual cortex. In contrast, the left-sided towns recalled by hemineglect patients, revealed that they have some spatial inconsistency or representational difficulty. Hemianopic patients positioned and maintained their gaze in their contralesional hemispace, suggesting that their mental map was not centered on their head or body midline. This contralesional gaze positioning appeared to be a general compensation strategy and was not observed in patients with neglect (with or without hemianopia). Instead, neglect patients positioned their gaze in their ipsilesional hemispace and only when performing the visual imagery task. These findings are discussed in the context of the role of occipital and fronto-parietal cortices in the neuroanatomical model of visual imagery developed by Kosslyn et al. (2006).

Resume Les nystagmus acquis centraux ou les autres types de mouvements oculaires anormaux d’origine neurologique ont pour certains une valeur semeiologique interessante. Le mouvement oculaire anormal doit etre identifie par une observation precise du type de phase (lente ou rapide), de la direction, de son caractere mono- ou binoculaire, de sa frequence et de sa regularite, et dans le contexte pathologique general. Lorsque l’identification est precise et correcte, il peut etre un outil essentiel pour etablir un diagnostic topographique, etiologique et/ou pronostique de certaines affections neurologiques. Nous proposons dans ce chapitre une approche « pratique » visant a sensibiliser le neurologue a l’observation de mouvements oculaires anormaux pour ameliorer la finesse du diagnostic clinique.

The vestibulo-ocular reflex maintains gaze stabilization during angular or linear head accelerations, allowing adequate dynamic visual acuity. In case of bilateral vestibular hypofunction, patients use saccades to compensate for the reduced vestibulo-ocular reflex function, with covert saccades occurring even during the head displacement. In this study, we questioned whether covert saccades help maintain dynamic visual acuity, and evaluated which characteristic of these saccades are the most relevant to improve visual function. We prospectively included 18 patients with chronic bilateral vestibular hypofunction. Subjects underwent evaluation of dynamic visual acuity in the horizontal plane as well as video recording of their head and eye positions during horizontal head impulse tests in both directions (36 ears tested). Frequency, latency, consistency of covert saccade initiation, and gain of covert saccades as well as residual vestibulo-ocular reflex gain were calculated. We found no correlation between residual vestibulo-ocular reflex gain and dynamic visual acuity. Dynamic visual acuity performance was however positively correlated with the frequency and gain of covert saccades and negatively correlated with covert saccade latency. There was no correlation between consistency of covert saccade initiation and dynamic visual acuity. Even though gaze stabilization in space during covert saccades might be of very short duration, these refixation saccades seem to improve vision in patients with bilateral vestibular hypofunction during angular head impulses. These findings emphasize the need for specific rehabilitation technics that favor the triggering of covert saccades. The physiological origin of covert saccades is discussed.

Resume Les mouvements oculaires anormaux correspondent essentiellement aux nystagmus et aux intrusions ou oscillations saccadiques, plus rarement a des derives oculaires ou des tremblements oculaires paroxystiques. Ils sont source d’une instabilite retinienne, dont la consequence fonctionnelle est une oscillopsie le plus souvent associee a une alteration de l’acuite visuelle. L’oscillopsie est cependant absente lorsque l’instabilite oculaire se developpe chez des patients malvoyants ou dans le cadre de nystagmus infantiles. L’examen d’un mouvement oculaire anormal depend du contexte clinique dans lequel le patient consulte, notamment si le mouvement oculaire anormal est observe chez un patient asymptomatique, malvoyant, vertigineux ou decrivant des oscillopsies. Dans ce dernier cas, la description precise des caracteristiques du mouvement oculaire anormal permet d’orienter le plus souvent le diagnostic topographique, parfois le diagnostic etiologique et la prise en charge therapeutique symptomatique.

International audience; PURPOSE: Radiotherapy has shown its efficacy in controlling optic nerve sheath meningiomas (ONSM) tumor growth while allowing visual acuity to improve or stabilize. However, radiation-induced toxicity may ultimately jeopardize the functional benefit. The purpose of this study was to identify predictive factors of poor visual outcome in patients receiving radiotherapy for ONSM. METHODS AND MATERIALS: We conducted an extensive analysis of 10 patients with ONSM with regard to clinical, radiologic, and dosimetric aspects. All patients were treated with conformal radiotherapy and subsequently underwent biannual neuroophthalmologic and imaging assessments. Pretreatment and posttreatment values of visual acuity and visual field were compared with Wilcoxon's signed rank test. RESULTS: Visual acuity values significantly improved after radiotherapy. After a median follow-up time of 51 months, 6 patients had improved visual acuity, 4 patients had improved visual field, 1 patient was in stable condition, and 1 patient had deteriorated visual acuity and visual field. Tumor control rate was 100% at magnetic resonance imaging assessment. Visual acuity deterioration after radiotherapy was related to radiation-induced retinopathy in 2 patients and radiation-induced mature cataract in 1 patient. Study of radiotherapy parameters showed that the mean eye dose was significantly higher in those 3 patients who had deteriorated vision. CONCLUSIONS: Our study confirms that radiotherapy is efficient in treating ONSM. Long-term visual outcome may be compromised by radiation-induced side effects. Mean eye dose has to be considered as a limiting constraint in treatment planning.

Resume Introduction L’angiopathie vasospastique idiopathique de l’artere carotide interne est une cause rare et mal connue d’accident vasculaire cerebral ischemique. Methodes Nous rapportons le cas d’un homme de 39 ans, migraineux, traite par betabloquants, qui presenta une baisse de vision de l’œil droit, des cephalees, puis une crise d’epilepsie generalisee tonicoclonique suivie d’une hemiparesie gauche. L’examen ophtalmologique revela une ischemie retinienne de l’œil droit et une hemianopsie laterale homonyme gauche incomplete. L’IRM montra une stenose allongee des deux carotides internes au niveau cervical et une ischemie sylvienne droit recente. Le diagnostic d’angiopathie vasospastique idiopathique de l’artere carotide interne fut pose grâce aux IRM de controle et un doppler des arteres cervicales, qui objectiverent la regression de la stenose carotidienne et l’absence d’hematome parietal. L’evolution clinique sous inhibiteur calcique et aspirine fut favorable. Les traitements vasoconstricteurs sont contre-indiques. Discussion/conclusion L’angiopathie vasospastique limitee aux carotides internes a ete peu documentee dans la litterature. Le role du terrain migraineux a ete evoque. L’etiologie peut etre meconnue, si l’exploration des vaisseaux du cou n’est pas precoce et renouvelee. Des recidives ont ete rapportees, justifiant pour certains auteurs un traitement specifique vasodilatateur en prevention secondaire. Les traitements vasoconstricteurs sont contre-indiques.

Objective To propose a method of diagnosis of mild papilloedema (PO) using peripapillary total retinal (PTR) thickness measurement by spectral domain optical coherence tomography (OCT). Methods 24 eyes in 24 patients with PO caused by increased intracranial pressure and 22 eyes in 22 normal subjects were studied. OCT high-quality fundus images were analysed and graded by three masked observers using the Modified Frisen Scale. Eyes with PO were divided into two subgroups: those with mild PO (n=18) and those with moderate-severe PO (n=6). Two methods of measurements were evaluated and compared: retinal nerve fibre layer (RNFL) thickness measurements using standard optic disc cube 200×200 acquisition protocol and PTR thickness measurements using the ‘macular’ cube 512×128 acquisition protocol centred on the optic disc. Thickness values were calculated globally and for each quadrant (temporal, superior, nasal, inferior) and compared among the three groups (control, mild PO, moderate-severe PO). The main outcome measures were RNFL and PTR thickness. Results Average RNFL and PTR thickness in the moderate-severe PO, mild PO and control groups were 299.3±10.9, 112.4±6.3, 96±5.7 and 804.5±17, 463.1±9.8 and 332.4±8.9 μm, respectively. Moderate-severe PO differed from mild PO and control groups using both RNLF thicknesses and PTR thicknesses measurements. Mild PO did not differ from controls using RNLF thickness measurement (p=0.17), but was statistically different using PTR thickness measurement (p Conclusion PTR thickness measurement increases the sensitivity of detection of mild PO compared with conventional RNFL measurement. This new way of using OCT may be useful for clinicians to detect mild PO.

In the June issue of Expert Review of Ophthalmology, a review was published covering the complete scientific knowledge concerning the clinical and pathophysiological aspects of eye movement disorde...

In this chapter we describe a variety of rare but clinically identifiable ocular motor syndromes, including ocular neuromyotonia, superior oblique myokymia, ocular motor synkinesis, third nerve palsy with cyclic spasms, and paroxysmal manifestations of multiple sclerosis. These syndromes share many characteristics. They result from neurogenic hyperactivity, causing episodic spasms of one or several extraocular muscles. The pathophysiology is not fully understood, but it usually includes both a focal and partial lesion of one of the ocular motor nerves and a central rearrangement of neuronal activity in the ocular motor nuclei. Treatment with membrane-stabilizing agents, such as carbamazepine, is usually effective to reduce the symptoms. The above-mentioned syndromes result from a number of different diseases. A proportion of apparently idiopathic cases may be related to a neurovascular compression syndrome.

Vertigo is an illusion of rotatory or linear movement that demonstrates a functional or lesional disturbance of the vestibular system, from periphery to central connections. According to the ANAES report (1997), benign paroxysmal positional vertical vertigo, vestibular neuronitis and Meniere's disease account for 40-50% of all mixed vertigo etiologies. Central etiologies may account for 20-40% of causes and 10-40% remain more difficult to classify, and are usually classified under the term of "peripheral vestibulopathy." These include vertigo due to neurovascular compression syndrome of the VIIIth nerve. Clinical manifestations, differential diagnosis, and treatment of the main etiologies of vertigo will be developed in this chapter. A specific section will discuss the subject of neurovascular compression syndrome of the VIIIth nerve. Even though some publications should be challenged, it appears that neurovascular compression syndrome of the VIIIth nerve might explain some cases of vertigo or chronic instability, with or without cochlear signs. The diagnosis is difficult and must be established on multiple clinical, electrophysiological and radiological arguments. A therapeutic test with antiepileptic drugs is helpful. The treatment includes these drugs as a first option but may require a neurosurgical approach if medical treatment fails.

The vestibular system detects head movements such as angular rotation, translation, and head position relative to gravity. It acts to stabilize the eyes and posture through subcortical reflexes. Its signals are also integrated at the cortical level to participate in the elaboration of a body scheme, used for different functions such as spatial orientation and motor control. The vestibular nerve shows a resting discharge rate that is modulated up or down according to head motion or position. Central functioning depends on the detection of an asymmetry between signals coming from a pair of peripheral sensors, one on either side. In pathological cases, unilateral peripheral dysfunction is interpreted by the central system as an asymmetry resulting from a change in head position leading to nystagmus, postural disturbances, and vertigo. The dysfunction can be either a deficit, such as observed in vestibular neuronitis, or hyperactivity such as observed in neurovascular compression syndrome of the VIIIth nerve. Anatomically, the VIIIth nerve has a long Root Entry Zone (REZ) that extends over 10 mm before entering the brainstem. The VIIIth nerve is also physiologically close to numerous vessels at the pontocerebellar angle and internal auditory meatus. Therefore, vestibular syndrome resulting from neurovascular compression syndrome of the VIIIth nerve may exist, but it is very difficult to prove using radiological imagery.

Clinical and functional assessment of the vestibular nerve is fundamental in demonstrating vestibular signs and searching for associated otological and neurological signs. This may help orient topographic diagnosis toward central or peripheral syndrome and etiologic diagnosis.

Neurosarcoidosis is a rare disease that can involve all the nervous system with variable clinical onset and prognosis. The initial therapeutic approach is mainly based on corticosteroids and immunosuppressive agents. Treatment of refractory forms of neurosarcoidosis is not well established and emerging immunomodulating drugs like infliximab have been recently tested. The clinical report of a new case of neurosarcoidosis responding to infliximab is followed by a review of the new therapeutic agents available for the treatment of refractory neurosarcoidosis.

Resume Le meningiome est une affection tumorale rare du nerf optique. La presentation clinique etant peu specifique et l’acces a l’anatomo-pathologie difficile, le diagnostic positif repose sur l’imagerie. Son traitement reste controverse. Nous rapportons notre experience de vingt-et-un cas de meningiome du nerf optique (MNO) chez vingt patients. La majorite de nos patients etaient des femmes, d’âge moyen 47 ans. Le MNO s’est revele le plus souvent par un trouble visuel. L’examen ophtalmologique etait generalement altere (acuite visuelle, champ visuel, fond d’œil). L’IRM centree sur le nerf optique, avec injection de gadolinium et saturation de la graisse orbitaire etait l’examen de choix pour le diagnostic. Un tiers des patients avaient un examen ophtalmologique stable au terme du suivi, sans traitement agressif. La radiotherapie fractionnee conformationnelle etait le seul traitement semblant susceptible d’ameliorer le pronostic fonctionnel. Ses indications et modalites restent a preciser.

Oscillopsia is an illusion of an unstable visual world. It is associated with poor visual acuity and is a disabling and stressful symptom reported by numerous patients with neurological disorders. The goal of this paper is to review the physiology of the systems subserving stable vision, the various pathophysiological mechanisms of oscillopsia and the different treatments available. Visual stability is conditioned by two factors. First, images of the seen world projected onto the retina have to be stable, a sine qua non condition for foveal discriminative function. Vestibulo-ocular and optokinetic reflexes act to stabilize the retinal images during head displacements; ocular fixation tends to limit the occurrence of micro ocular movements during gazing; a specific system also acts to maintain the eyes stable during eccentric gaze. Second, although we voluntary move our gaze (body, head and eye displacements), the visual world is normally perceived as stable, a phenomenon known as space constancy. Indeed, complex cognitive processes compensate for the two sensory consequences of gaze displacement, namely an oppositely-directed retinal drift and a change in the relationship between retinal and spatial (or subject-centered) coordinates of the visual scene. In patients, oscillopsia most often results from abnormal eye movements which cause excessive motion of images on the retina, such as nystagmus or saccadic intrusions or from an impaired vestibulo-ocular reflex. Understanding the exact mechanisms of impaired eye stability may lead to the different treatment options that have been documented in recent years. Oscillopsia could also result from an impairment of spatial constancy mechanisms that in normal condition compensate for gaze displacements, but clinical data in this case are scarce. However, we suggest that some visuo-perceptive deficits consecutive to temporo-parietal lesions resemble oscillopsia and could result from a deficit in elaborating spatial constancy.

Introduction La myotonie de Thomsen est une myotonie non dystrophique de transmission autosomique dominante. Nous rapportons le cas d′une famille associant myotonie congenitale de Thomsen, strabisme et myopathie oculaire. Par la suite, nous avons examine six autres patients atteints de myotonie et deux temoins. Nous nous sommes plus particulierement interesses a l′enregistrement des saccades oculaires de ces patients (amplitude et vitesse). Patients et methodes Nous rapportons le cas d′une famille presentant une myotonie de Thomsen et un strabisme. Un bilan oculomoteur avec video et enregistrement electro-oculographique a ete realise chez trois patientes de cette famille. Les sept autres patients, recrutes en service de neurologie, ont ete evalues par enregistrement electro-oculographique, selon quatre programmes de saccades differents. Resultats Les patients du cas familial presentaient de facon constante un strabisme convergent, associe ou non a un element vertical. Une limitation et une lenteur d′execution des mouvements oculaires, typiques des atteintes myogenes etaient notees dans chaque cas. Les enregistrements electro-oculographiques mettaient en evidence un ralentissement et un allongement de la duree des saccades. Seuls les patients atteints d′une myotonie de Steinert, dans les cas sporadiques, presentaient des anomalies des saccades. Discussion Nous retrouvons une myopathie oculaire chez differents membres d′une famille presentant une myotonie de Thomsen. Aucun cas signalant cette association n′est rapporte dans la litterature. L′evaluation des cas sporadiques par un enregistrement electro-oculographique, temoigne, uniquement dans le cas de la myotonie dystrophique de Steinert, d′une atteinte oculaire. Conclusion Il s′agit d′une observation originale de myotonie de Thomsen avec atteinte, clinique et electro-oculographique, de la musculature oculaire extrinseque et strabisme. La physiopathologie de ces troubles reste a decouvrir.

We review the question of diagnosis of painful and relatively isolated ophthalmoplegia due to diseases affecting the ocular motor nerves. For each clinical setting, we provide an overview of the main causes and a practical way to approach the diagnosis. As vascular malformations should always be kept in mind in patients with painful ophthalmoplegia, emergency neuroradiological investigations may be needed. However, the etiological scope is wide and the rationale for choosing the more appropriate examination and its optimal timing depends exclusively on the clinical evaluation. Despite advances in investigation techniques, diagnosis may remain difficult or even unresolved in a certain number of patients. We discuss successively paralysis of the third, sixth and fourth nerve, paralysis of several ocular motor nerves, recurrent ophthalmoplegia and ischaemic ocular motor palsies, which are the most frequent cause.

We report the case of a 57-year-old man who presented bilateral subacute and painless optic neuropathy after meningopolyradiculitis revealing a primary human immunodeficiency virus infection. Both antiretroviral and steroid treatments were ineffective. Clinical symptoms and evolutive pattern were consistent with a mechanism of microvascular ischaemia of the optic nerve head. Optic neuropathies related to HIV infection are rare compared to those resulting from opportunistic infections. There are several pathophysiological mechanisms involved.

International audience; The cerebellum is critically involved in the adaptation mechanisms that maintain the accuracy of goaldirected acts such as saccadic eye movements. Two categories of saccades, each relying on different adaptation mechanisms, are defined: reactive (externally triggered) saccades and voluntary (internally triggered) saccades. The contribution of the medio-posterior part of the cerebellum to reactive saccades adaptation has been clearly demonstrated, but the evidence that other parts of the cerebellum are also involved is limited. Moreover, the cerebellar substrates ofvoluntary saccades adaptation have only been marginally investigated. Here, we addressed these two questions by investigating the adaptive capabilities of patients with cerebellar or pre-cerebellar stroke. We recruited three groups of patients presenting focal lesions located, respectively in the supero-anterior cerebellum, the infero-posterior cerebellum and the lateral medulla (leading to a Wallenberg syndrome including motor dysfunctions similar to those resulting from lesion of the medio-posterior cerebellum). Adaptations of reactive saccades and of voluntary saccades were tested during separate sessions in all patients and in a group of healthy participants. The functional lesion ofthe medio-posterior cerebellum in Wallenberg syndrome strongly impaired the adaptation of both reactive and voluntary saccades. In contrast, patients with lesion in the supero-anterior part of the cerebellum presented a specific adaptation deficit of voluntary saccades. Finally, patientswith an infero-posterior cerebellar lesion showed mild adaptation deficits. We conclude that the medio-posterior cerebellum is critical for the adaptation of both saccade categories, whereas the supero-anterior cerebellum is specifically involved in the adaptation of voluntary saccades.

Abnormal eye movements in multiple sclerosis (MS) are often persistent and known to be associated with general disability. However, there is no precise knowledge concerning their incidence and resulting visual handicap. The aim of our study was to describe the persistent ocular motor manifestations in MS and relate them to visual functions tested with visual acuity and with a vision-related questionnaire. We selected 24 MS patients complaining of persistent visual disability associated with ocular motor manifestations without any anterior visual pathway deficit. Internuclear ophthalmoplegia was the most frequently observed symptom, followed by gaze-evoked nystagmus, saccadic hypermetria, and then pendular nystagmus. Pendular nystagmus, saccadic hypermetria, and the association of internuclear ophthalmoplegia and gaze-evoked nystagmus were associated with decreased visual acuity and visual functional scores. There was a correlation between the number of abnormal eye movements and visual functions. This study demonstrates that ocular motor dysfunction in MS induces specific visual dysfunction and handicap.

Voluntary or reactive saccades predominate in rapid eye movements. Their goal is to preserve an active and optimal visual perception of the environment. Saccades cannot be guided once launched. Oculomotor plasticity, or saccadic adaptation, is still partially unknown, in particular the role played by the basal ganglia. New neuro-ophthalmological rehabilitation techniques require understanding the neurophysiological basis and demonstrating the neuronal structures involved in this plasticity.This study assessed the reactive saccade adaptation in patients with idiopathic Parkinson disease, as a model of basal ganglia dysfunction. We predicted that saccadic adaptation would be preserved in this pathology.Five patients with mild idiopathic hemi-Parkinson disease were included, as well as four age-matched controls. Reactive saccade adaptation was studied using the double-step target paradigm, in patients with OFF-Dopa treatment and in controls.Group analysis demonstrated that patients had a lower level of adaptation than the controls (p0.05). Individually, two patients did not adapt for bilateral saccades and one for ipsilateral (compared to Parkinson motor clinical syndrome) saccades. Two additional patients adapted on both sides but with a deficit in contralateral saccades when compared to the control group.These preliminary results suggest basal ganglia involvement in reactive saccadic adaptation, which remains to be clarified.

International audience; Two patients with Parkinson's disease with pedunculopontine nucleus (PPN) stimulation for gait impairments reported "trembling vision" during the setting of the electrical parameters, although there was no clinically observable abnormal eye movement. Oculomotor recordings revealed frequency locked voltage dependent vertical or oblique movements of the eye ipsilateral to the active contact, suggesting current spreading to the mesencephalic oculomotor fibres. These results emphasise the difficulty of stimulating this mesencephalic region.

In this chapter we describe a variety of rare but clinically identifiable ocular motor syndromes, including ocular neuromyotonia, superior oblique myokymia, ocular motor synkinesis, third nerve palsy with cyclic spasms, and paroxysmal manifestations of multiple sclerosis. These syndromes share many characteristics. They result from neurogenic hyperactivity, causing episodic spasms of one or several extraocular muscles. The pathophysiology is not fully understood, but it usually includes both a focal and partial lesion of one of the ocular motor nerves and a central rearrangement of neuronal activity in the ocular motor nuclei. Treatment with membrane-stabilizing agents, such as carbamazepine, is usually effective to reduce the symptoms. The above-mentioned syndromes result from a number of different diseases. A proportion of apparently idiopathic cases may be related to a neurovascular compression syndrome.

The vestibular system detects head movements such as angular rotation, translation, and head position relative to gravity. It acts to stabilize the eyes and posture through subcortical reflexes. Its signals are also integrated at the cortical level to participate in the elaboration of a body scheme, used for different functions such as spatial orientation and motor control. The vestibular nerve shows a resting discharge rate that is modulated up or down according to head motion or position. Central functioning depends on the detection of an asymmetry between signals coming from a pair of peripheral sensors, one on either side. In pathological cases, unilateral peripheral dysfunction is interpreted by the central system as an asymmetry resulting from a change in head position leading to nystagmus, postural disturbances, and vertigo. The dysfunction can be either a deficit, such as observed in vestibular neuronitis, or hyperactivity such as observed in neurovascular compression syndrome of the VIIIth nerve. Anatomically, the VIIIth nerve has a long Root Entry Zone (REZ) that extends over 10mm before entering the brainstem. The VIIIth nerve is also physiologically close to numerous vessels at the pontocerebellar angle and internal auditory meatus. Therefore, vestibular syndrome resulting from neurovascular compression syndrome of the VIIIth nerve may exist, but it is very difficult to prove using radiological imagery.

Vertigo is an illusion of rotatory or linear movement that demonstrates a functional or lesional disturbance of the vestibular system, from periphery to central connections. According to the ANAES report (1997), benign paroxysmal positional vertical vertigo, vestibular neuronitis and Ménière's disease account for 40-50% of all mixed vertigo etiologies. Central etiologies may account for 20-40% of causes and 10-40% remain more difficult to classify, and are usually classified under the term of "peripheral vestibulopathy." These include vertigo due to neurovascular compression syndrome of the VIIIth nerve. Clinical manifestations, differential diagnosis, and treatment of the main etiologies of vertigo will be developed in this chapter. A specific section will discuss the subject of neurovascular compression syndrome of the VIIIth nerve. Even though some publications should be challenged, it appears that neurovascular compression syndrome of the VIIIth nerve might explain some cases of vertigo or chronic instability, with or without cochlear signs. The diagnosis is difficult and must be established on multiple clinical, electrophysiological and radiological arguments. A therapeutic test with antiepileptic drugs is helpful. The treatment includes these drugs as a first option but may require a neurosurgical approach if medical treatment fails.

Clinical and functional assessment of the vestibular nerve is fundamental in demonstrating vestibular signs and searching for associated otological and neurological signs. This may help orient topographic diagnosis toward central or peripheral syndrome and etiologic diagnosis.

Sensory-motor adaptation processes are critically involved in maintaining accurate motor behavior throughout life. Yet their underlying neural substrates and task-dependency bases are still poorly understood. We address these issues here by studying adaptation of saccadic eye movements, a well-established model of sensory-motor plasticity. The cerebellum plays a major role in saccadic adaptation but it has not yet been investigated whether this role can account for the known specificity of adaptation to the saccade type (e.g., reactive versus voluntary). Two patients with focal lesions in different parts of the cerebellum were tested using the double-step target paradigm. Each patient was submitted to two separate sessions: one for reactive saccades (RS) triggered by the sudden appearance of a visual target and the second for scanning voluntary saccades (SVS) performed when exploring a more complex scene. We found that a medial cerebellar lesion impaired adaptation of reactive-but not of voluntary-saccades, whereas a lateral lesion affected adaptation of scanning voluntary saccades, but not of reactive saccades. These findings provide the first evidence of an involvement of the lateral cerebellum in saccadic adaptation, and extend the demonstrated role of the cerebellum in RS adaptation to adaptation of SVS. The double dissociation of adaptive abilities is also consistent with our previous hypothesis of the involvement in saccadic adaptation of partially separated cerebellar areas specific to the reactive or voluntary task (Alahyane et al. Brain Res 1135:107-121 (2007)).

Multiple sclerosis is the most common disabling neurological disease in young people. Many neuro-ophthalmological manifestations can occur during the course of the illness, and optic neuritis is both the most frequent and the best known. However, some ocular motility disorders can also occur, but since there may be no symptoms, they often remain underdiagnosed. These eye movement disorders are mostly related to brain-stem and cerebellum lesions. They can be acute, indicating a spatial dissemination of the demyelinating disease, and consequently may indicate the need for systemic treatment of multiple sclerosis. More often, they evolve slowly, progressing with the multiple sclerosis. In this case, they could provide a clue to the prognosis of the disease. In this survey, we discuss the two major symptoms of ocular motor disorders likely to occur during multiple sclerosis: oscillopsia and diplopia.

International audience; In humans, habituation of vestibulo-ocular reflex (VOR) by repeated caloric or rotational stimulation has been well documented. However, less attention has been directed to the effect of habituation on the sensation of self-rotation and little is known about the retention duration of vestibular habituation. To investigate these characteristics, subjects were exposed to ten sessions of angular velocity steps in yaw, with a chair rotating either alternatively in both CW and CCW directions (bidirectional protocol) or always in the same direction (unidirectional protocol), i.e., CW or CCW. The retention of habituation of VOR and sensation of rotation induced by both protocols was studied for a period up to 8 months following the end of the habituation protocols. There was a progressive decline in the VOR peak slow phase velocity and time constant throughout the sessions during both protocols. These parameters then followed an exponential recovery with a time constant of about 1 month. The duration of the sensation of rotation also habituated during repeated angular velocity steps, but it was shorter for both directions of stimulation, including after the unidirectional protocol. Sinusoidal VOR gain was not affected by vestibular habituation to velocity steps, but sinusoidal VOR phase showed an increase in phase lead at 0.02 and 0.04 Hz, which also returned to baseline values within about 1 month. We conclude that vestibular habituation is a long-lasting phenomenon. These results may be helpful for designing and scheduling the protocols for drug studies using crossover design, rehabilitation of balance disorder patients, and for the application of intermittent artificial gravity during space missions.

International audience; OBJECTIVE: To determine the effect of subthalamic stimulation on visually triggered eye and head movements in patients with Parkinson's disease (PD). METHODS: We compared the gain and latency of visually triggered eye and head movements in 12 patients bilaterally implanted into the subthalamic nucleus (STN) for severe PD and six age-matched control subjects. Visually triggered movements of eye (head restrained), and of eye and head (head unrestrained) were recorded in the absence of dopaminergic medication. Bilateral stimulation was turned OFF and then turned ON with voltage and contact used in chronic setting. The latency was determined from the beginning of initial horizontal eye movements relative to the target onset, and the gain was defined as the ratio of the amplitude of the initial movement to the amplitude of the target movement. RESULTS: Without stimulation, the initiation of the head movement was significantly delayed in patients and the gain of head movement was reduced. Our patients also presented significantly prolonged latencies and hypometry of visually triggered saccades in the head-fixed condition and of gaze in head-free condition. Bilateral STN stimulation with therapeutic parameters improved performance of orienting gaze, eye and head movements towards the controls' level CONCLUSIONS: These results demonstrate that visually triggered saccades and orienting eye-head movements are impaired in the advanced stage of PD. In addition, subthalamic stimulation enhances amplitude and shortens latency of these movements. SIGNIFICANCE: These results are likely explained by alteration of the information processed by the superior colliculus (SC), a pivotal visuomotor structure involved in both voluntary and reflexive saccades. Improvement of movements with stimulation of the STN may be related to its positive input either on the STN-Substantia Nigra-SC pathway or on the parietal cortex-SC pathway.

Neurosarcoidosis is a rare disease that can involve all the nervous system with variable clinical onset and prognosis. The initial therapeutic approach is mainly based on corticosteroids and immunosuppressive agents. Treatment of refractory forms of neurosarcoidosis is not well established and emerging immunomodulating drugs like infliximab have been recently tested. The clinical report of a new case of neurosarcoidosis responding to infliximab is followed by a review of the new therapeutic agents available for the treatment of refractory neurosarcoidosis.

The brainstem vestibulo-oculomotor pathways are not yet fully known. Three different excitatory tracts could be involved in the transmission of upward vestibular eye movement (VEM) signals and upward eye position (EP) signals to the oculomotor nucleus (III): the medial longitudinal fasciculus (MLF), the brachium conjunctivum (BC), and the crossing ventral tegmental tract (CVTT). The involvement of the MLF pathway originating in the medial vestibular nucleus (MVN) in this transmission is experimentally and clinically well established whereas a role of the BC appears to be questionable. Furthermore, there is now accumulating evidence that the CVTT pathway emerging from the superior vestibular nucleus (SVN) also plays an important role in the mediation of excitatory upward EP and VEM signals to the III. This duplication of pathways (MVN-MLF and SVN-CVTT) could be explained by a supplementary and relatively specific function performed by the SVN-CVTT pathway to counteract the gravity pull in the upward eye movement system. Various arguments in support of this hypothesis are reviewed.

Meningioma is an unfrequent optic nerve tumor. Clinical symptoms are not specific, and pathology exam not easily accessible. The diagnosis is usually based on imaging findings. We report our experience, based on twenty patients. Most of them were middle-aged women (mean age=47 years old). The optic nerve meningioma (ONM) was often revealed by visual dysfunction. Ophthalmological evaluation was altered in most patients (visual acuity, visual fields, fundi). The gold-standard exam was MRI of the optic nerve, with and without gadolinium, and with fat-sat sequences. Thirty percent of the lesions remain stable without treatment. Functional prognosis has been improved only by conformal fractionated radiotherapy, but indications and modalities remain to be specified.

International audience; Contraversive eye deviation (CED) is most often observed intraoperatively during subthalamic nucleus implantation for Parkinson's disease and considered to result from wrong electrode positioning. We report on a woman, bilaterally implanted in the subthalamic nucleus for severe Parkinson's disease disclosing long-lasting CED only when the stimulators were activated separately. Clinical examination and eye movements recording in this patient showed that CED occurred when stimulation was applied at the site and at similar intensity used for the best antiparkinsonian effect. These results suggest that the subthalamic area may be involved in orienting movements, either through the subthalamic nucleus itself or the fibers from the Frontal Eye Fields. Interestingly, this report shows that CED may be corrected by bilateral stimulation and that CED may not necessarily implicate electrode repositioning.

Opsoclonus–myoclonus syndrome (OMS) is a rare condition that includes chaotic multidirectional saccadic eye movements associated with myoclonus and ataxia. In adults, it is usually considered to be an autoimmune disease occurring either in a paraneoplastic context or after central nervous system infection. We report the case of a patient who presented with the classic features of OMS as a manifestation of acute Borrelia burgdorferi infection that was shown both on serum and cerebrospinal fluid examination. The outcome was favourable after prolonged antibiotic treatment. Lyme disease could be added to the list of aetiologies to be screened in OMS, as it would allow effective treatment and avoidance of unnecessary investigations.

Thomsen myotonia is an autosomal dominant, but not dystrophic myotonia. We report a family case associating congenital Thomsen's myotonia, strabismus, and ocular myopathy. We successively studied seven isolated patients presenting a myotonic disease and two controls and recorded the ocular saccades of these patients (amplitude, velocity) as a comparison for our family case.Four women from the same family presented Thomsen myotonia associated with strabismus. In addition to the clinical manifestations, the electro-oculographic analysis showed saccade alterations. The saccades of the seven other isolated patients, recruited in a neurology department, were evaluated by electro-oculographic recordings according to four different paradigms.The patients within our family case all presented esotropia, with or without a vertical oculomotor disorder. Clinical examination reported alterations in ocular motility--impairment and slowness of ocular movements--suggesting a myopathic disorder. The electro-oculographic recordings reported a slowing of saccades with increasing duration. For the isolated cases, the slowing of saccades observed was only reported for the patients with myotonic dystrophy (Steinert disease); nevertheless, we failed to show any myotonic phenomena.No cases associating Thomsen myotonia, strabismus, and electro-oculographic disorders have been reported in the literature to date. The electro-oculographic slowing of saccades is not rare in myotonic dystrophy (Steinert disease), but in Thomsen myotonia this has never been reported.This is the first report concerning Thomsen myotonia associated with strabismus and alterations of saccades. The mechanism of this disorder has yet to be discovered, as for Steinert disease.

We report the case of a 57-year-old man who presented bilateral subacute and painless optic neuropathy after meningopolyradiculitis revealing a primary human immunodeficiency virus infection. Both antiretroviral and steroid treatments were ineffective. Clinical symptoms and evolutive pattern were consistent with a mechanism of microvascular ischaemia of the optic nerve head. Optic neuropathies related to HIV infection are rare compared to those resulting from opportunistic infections. There are several pathophysiological mechanisms involved.

International audience; Saccadic lateropulsion is characterized by an undershoot of contralaterally directed saccades, an overshoot of ipsilaterally directed saccades and an ipsilateral deviation of vertical saccades. In Wallenberg syndrome, it is thought to result from altered signals in the olivo-cerebellar pathway to the oculomotor cerebellar network. In the current study we aimed to determine whether saccadic lateropulsion results from a cerebellar impairment of motor related signals or visuo-spatial related signals. We studied the trajectory, the accuracy, the direction and the amplitude of a variety of vertical and oblique saccades produced by Wve patients and nine control subjects. Some results are consistent with previous data suggesting altered motor related signals. Indeed, the horizontal error of contralesional saccades in patients increased with the desired horizontal saccade size. Furthermore, the initial directional error measured during the saccadic acceleration phase was smaller than the global directional error, suggesting that the eye tra-jectory curved progressively. However, some other results suggest that the processes that specify the horizontal spatial goal of the saccades might be impaired in the patients. Indeed, the horizontal error of ipsilesional saccades in patients did not change signiWcantly with the desired horizontal saccade size. In addition, when comparing saccades with similar intended direction, it was found that the directional error was inversely related to the vertical saccade amplitude. Thus we conclude that the cerebellum might be involved both in controlling the motor execution of saccades and in determining the visuo-spatial information about their goal.

Creutzfeldt-Jakob's disease has various anatomoclinical presentations including a rare form with preponderant visual signs described by Heidenhain. In this form, the visual symptoms may be isolated for a few weeks, leading to multiple ophthalmological examinations.We report the case of a 75-year-old woman who developed isolated visual disorders which rapidly increased over a period of two months. Addition of neurological symptoms, abnormalities of EEG and positivity of 14-3-3 protein led to the diagnosis of Creutzfeldt-Jakob's disease. The patient died 14 months after the first neuroophthalmologic signs. The diagnosis was established by post-mortem examination and immuno-electrophoretic demonstration of type 1 prion protein.Heidenhain's form of Creutzfeldt-Jakob's disease highlights the importance of general rules for prevention of iatrogenic hazard during ophthalmological examinations.