Eye Nystagmus Research Articles

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

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

Multifractal characterization of nystagmus eye movements.

In this work, we investigate the multifractal properties of eye movement dynamics of children with infantile nystagmus, particularly the fluctuations of its velocity. The eye movements of three children and one adult with infantile nystagmus were evaluated in a simple task in comparison with 28 children with no ocular pathologies. Four indices emerge from the analysis: the classical Hurst exponent, the singularity strength corresponding to the maximum of the singularity spectrum, the asymmetry of the singularity spectrum, and the multifractal strength, each of which characterizes a particular aspect of eye movement dynamics. Our findings indicate that, when compared to children with no ocular pathologies, patients with infantile nystagmus present lower values of all indices. Except for the multifractal strength, the difference in the remaining indices is statistically significant. To test whether the characterization of patients with infantile nystagmus in terms of multifractality indices allows them to be distinguished from children without ocular pathologies, we performed an unsupervised clustering analysis and classified the subjects using supervised clustering techniques. The results indicate that these indices do, indeed, distinctively characterize the eye movements of patients with infantile nystagmus.

Internuclear ophthalmoplegia as a presentation of procedural stroke: a case report

BackgroundCardiac catheterization and endovascular procedures are extensively used in modern medicine, and procedural stroke is one of the major complications that the catheterization laboratory team may face in their everyday work. Recognizing the signs and symptoms of procedural stroke is crucial to ensuring appropriate management. We herein report a case of internuclear ophthalmoplegia that caused blurred vision, diplopia, and dizziness on lateral gaze as an unusual presentation of procedural stroke.Case presentationA 60-year-old Thai woman underwent right partial colectomy and was diagnosed with stage IV diffuse large B-cell lymphoma. Pre-chemotherapy echocardiography revealed mild left ventricular systolic dysfunction, and she therefore underwent diagnostic catheterization. Coronary angiography revealed normal coronary arteries, leading to a diagnosis of non-ischemic cardiomyopathy. After the procedure, she immediately developed dizziness and diplopia. During the right lateral gaze, she exhibited impaired adduction of the left eye and horizontal nystagmus of the right eye. A diagnosis of left internuclear ophthalmoplegia was made. Magnetic resonance imaging revealed a tiny area exhibiting characteristics of an acute infarct in the left paramedian midbrain, including the left medial longitudinal fasciculus, which explained the clinical picture. Another region of restricted diffusion indicating an acute infarct was detected in the right inferior cerebellar hemisphere. Magnetic resonance angiography revealed no significant cerebral artery disease. The patient achieved full neurological recovery 6 weeks after symptom onset.ConclusionThis report describes an uncommon presentation of procedural stroke that is likely to be misdiagnosed, especially by medical staff unfamiliar with internuclear ophthalmoplegia. Despite the good prognosis of internuclear ophthalmoplegia, appropriate stroke care is crucial in patients with procedural stroke because of the risk of multiple brain infarcts.

Solitary Sclerosis Presenting as Progressive Brainstem Symptoms

A woman in her 30s, presented with left facial weakness, left eyelid droop, left gaze diplopia as well as right facial and upper limb numbness; which progressively worsened over 1 month. She also developed dizziness, dysphonia, dysphagia, and an imbalanced gait. On exam, she had hoarseness, dysarthria, anisocoria; left pupil miosis, left eyelid ptosis, left gaze diplopia, left lower face weakness, deviation of the palate and uvula towards the left side, right eye nystagmus, right sided facial numbness, right upper limb numbness, right dysmetria, brisk reflexes all-over and an unsteady gait. The work up was positive for OCBs in the CSF analysis and MRI brain revealed a single progressive left medulla oblongata and left cerebellar peduncle hyperintensity lesion.

From WEMINO To WEBINO With Unilateral LMN Facial Palsy (P5-4.002)

<h3>Objective:</h3> To describe a case of progression from apparent trochlear nerve palsy, to wall-eyed monocular internuclear ophthalmoplegia (WEMINO), to wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) with unilateral lower motor neuron (LMN) facial palsy. <h3>Background:</h3> Various descriptions of INO with cranial nerve palsies are in the literature, but we report a patient with a remarkably instructive stepwise evolution. <h3>Design/Methods:</h3> Review of records of a patient with diplopia at our institution. <h3>Results:</h3> A 42-year-old woman presented acutely with oblique binocular diplopia worsening on right gaze and left head tilt, with left hypertropia. Trochlear nerve palsy was suspected but contrasted MRI brain with orbits, and initial CSF testing were unrevealing. On day 3, the hypertropia partly improved but she developed left eye adduction deficit. Given the fluctuation, myasthenia gravis was considered high in the differential diagnosis while test results were awaited. On day 7, she developed LMN left facial palsy and bilateral adduction deficit with abducting eye nystagmus, leading to the realization that a single progressing lesion in the pontine tegmentum could explain her entire sequence of events. Repeat MRI confirmed a minute enhancing lesion in the floor of the fourth ventricle corresponding to the dorsomedial surface of the left facial colliculus and bilateral medial longitudinal fasciculi (MLF), likely of demyelinating etiology. Her pending CSF tests returned with 7 oligoclonal bands. She received intravenous methylprednisolone and her symptoms nearly resolved by day 14. <h3>Conclusions:</h3> This patient presented with evolving symptoms that appeared to localize to the trochlear nerve initially, but lacked imaging correlate. It is clear in retrospect that her initial presentation represented a skew deviation from early INO, progressing to WEMINO and eventually WEBINO with unilateral fascicular facial palsy. The anatomical correlate was confirmed on repeated imaging. Her clinical course beautifully illustrates the importance of lesion localization for etiological diagnosis. <b>Disclosure:</b> Dr. Senthamarai Siddharthan has nothing to disclose. Dr. Witt has nothing to disclose. Dr. Kini has nothing to disclose. Dr. Vasireddy has nothing to disclose. The institution of Dr. Mathur Kumaraswamy has received research support from Woolsey Pharmaceuticals.

Eight-and-a-half syndrome as the first presentation of multiple sclerosis in an Asian male: a case report

BackgroundMultiple sclerosis is a diffuse chronic demyelinating disease of the central nervous system. It is relatively uncommon in the Asian population and even more so in males. Despite the usual involvement of the brainstem, eight-and-a-half syndrome remains a rare first presentation in multiple sclerosis. Only a few cases have been reported previously, but none involving the Asian population. Eight-and-a-half syndrome, a neuro-ophthalmological condition, is characterized by one-and-a-half syndrome with ipsilateral lower facial nerve palsy, which localizes lesions to the pontine tegmentum. This case report demonstrates the first case of eight-and-a-half syndrome as the first presentation of multiple sclerosis in an Asian male.Case presentationA healthy 23-year-old Asian man presented with sudden onset of diplopia followed by left-sided facial asymmetry for 3 days. Assessment of extraocular movement revealed left conjugate horizontal gaze palsy. On right gaze, there was limited left eye adduction and horizontal nystagmus of the right eye. These findings were consistent with a left-sided one-and-a-half syndrome. Prism cover test revealed left esotropia of 30 prism diopters. Cranial nerve examination showed left lower motor neuron facial nerve palsy, while other neurological examination was normal. Magnetic resonance imaging brain showed multifocal T2 fluid attenuated inversion recovery hyperintense lesions, involving bilateral periventricular, juxtacortical, and infratentorial regions. A focal gadolinium contrast-enhanced lesion with open ring sign on T1 sequence was seen at the left frontal juxtacortical region. Multiple sclerosis was diagnosed on the basis of the clinical and radiological evidence, which fulfilled the 2017 McDonald criteria. Positive oligoclonal bands in cerebrospinal fluid analysis further confirmed our diagnosis. He had a complete resolution of symptoms 1 month after a course of pulsed corticosteroid therapy, and was subsequently placed on maintenance therapy with interferon beta-1a.ConclusionThis case illustrates eight-and-a-half syndrome as the first presentation of a diffuse central nervous system pathology. A wide range of differential diagnoses needs to be considered in such a presentation as based on the patient’s demographics and risk factors.

Neuro-Optometric Treatment of Wall-eyed Bilateral Internuclear Ophthalmoplegia (WEBINO)

Background Wall-eyed Bilateral Internuclear Ophthalmoplegia (WEBINO) is an ocular motility disorder characterized by bilateral exotropia in primary gaze, bilateral internuclear ophthalmoplegia with defective adduction of both eyes and nystagmus of the contralateral eye on abduction. Convergence is impaired because the lesion is in the midbrain. The etiology of WEBINO includes demyelination, stroke, and tumors, but midbrain infarction is the most common.1 Although extraocular muscle surgery and botulinum toxin injections are typically used for management2 of WEBINO, neuro-optometric rehabilitation can be utilized as an effective option to improve vision. Case Report A 39-year-old Caucasian male with non-traumatic brain injury due to left intraparenchymal hemorrhage from stroke, presented with WEBINO and multiple vision signs and symptoms, including blurred vision, alternating exotropia, diplopia, and strabismus. During the previous 8 months, he participated in physical therapy, occupational therapy, and speech therapy. He had difficulty participating in his therapies due to his vision issues. Single vision distance lenses were prescribed to improve vision clarity and 6 in-office neuro-optometric rehabilitation sessions were administered to improve range of motion of eye movements and to improve vision. Conclusions Neuro-optometric rehabilitation utilizes a systematic approach to treating patients with binocular vision dysfunction, while integrating cognitive, motor, and sensory skills. Prognosis is optimized with an individualized approach. Top-down processing stimulates the brain in a more direct way to elicit plasticity-mediated motor relearning.3 In this case, extraocular muscle surgery and botulinum toxin injections were not optimal choices and neuro- optometric rehabilitation was utilized to manage WEBINO and improve quality of life.

Pineal Gland Mass presenting as Parinaud Syndrome in a 21 Year Old Patient

We report a case of a 21-year-old Filipino, with a history of progressive diplopia, who presented with headache, dizziness and vomiting. Ophthalmologic exam revealed light near dissociation, physiologic anisocoria, bilateral upgaze palsy, convergence retraction nystagmus and pseudo-abducens palsy of the left eye. Imaging was done, which revealed pineal neoplasm with obstructive hydrocephalus. This text aims to present a case of pineal gland neoplasm which presented as diplopia alongside signs and symptoms of Dorsal Midbrain Syndrome (Parinaud Syndrome).

Restructuring of the Optokinetic Reflex during Metamorphosis in Pelobates fuscus Laur.

The restructuring of the gaze stabilization system in Pelobates fuscus was investigated by quantitative analysis of the optomotor response using video imaging. Gaze stabilization is an important component in the system of neural mechanisms of visual depth perception. It was shown that the optomotor response in aquatic tadpoles of P. fuscus is similar to that of fish (movement of the animal in the direction of the visual background movement and eye nystagmus consisting of a fast and a slow phase). During metamorphosis (transition from the aquatic to the terrestrial lifestyle), froglets of P. fuscus responded to the movement of the visual background by eyes and head movements. One year after metamorphosis, P. fuscus responded to movement of the visual background as adult Anura: only by head movements (a slow and a fast phase), while eye movements were absent. Possible causes of the loss of active eye movements by Anura amphibians in the process of evolution are discussed.

Cavernous Sinus Meningioma Presenting with Unilateral Pseudo-Internuclear Ophthalmoplegia

Purpose: We report a case of cavernous sinus meningioma presenting with unilateral pseudo-internuclear ophthalmoplegia.Case summary: A 50-year-old female visited our clinic with a history of insidious onset of horizontal diplopia at primary and left gaze over 3 weeks. The symptom had diurnal variation and was aggravated with fatigue. There was intermittent upper eyelid drooping of the right eye. She had a history of migraines, which had recently worsened. The pupils showed a normal response to light and near stimulation in both eyes. The extraocular examination showed 14 prism diopter (PD) exotropia at primary, and 25 PD exotropia at left gaze, with -1 adduction limitation of the right eye. There was abducting nystagmus of the left eye. Ocular myasthenia gravis was suspected based on the clinical findings. Magnetic resonance imaging of the brain revealed a right cavernous sinus meningioma. The ocular symptoms improved after radiotherapy. At 3 months of follow-up, the ocular motility findings had improved to 4 PD exotropia, without adduction limitation of the right eye. The upper eyelid drooping had improved.Conclusions: A cavernous sinus meningioma can be manifested by various types of ocular motility disorder, including pseudo-internuclear ophthalmoplegia.

0839 Complex Sleep Apnea Improved with Decompression of a Chiari I Malformation in a Pediatric Patient

Abstract Introduction Chiari malformation (CM) occurs when a portion of the cerebellum herniates through the foramen magnum. CM is categorized as two types. Type 1 involves the cerebellar tonsils and type 2 involves the cerebellum and brain stem. Those with CM can be asymptomatic to having debilitating neurologic symptoms such as dysphagia, tinnitus, emesis, balance difficulty, muscle weakness, and/or headache. Central sleep apnea (CSA) and obstructive sleep apnea (OSA) have been associated with CM. It is postulated that the sleep disordered breathing (SDB) is due to compression of the medulla which houses the breathing center and cranial nerves that play a role in nocturnal breathing. OSA has been thought to be related to muscle weakness of the lower airway in those with CM. After resolving CM with surgical decompression, residual OSA is common requiring treatment with positive airway pressure therapy. Report of Cases: A 3-year-old male with a history of OSA and tonsillar hypertrophy. Polysomnography (PSG) was performed after tonsillectomy and adenoidectomy indicating severe OSA (oAHI 17.7/hr) and CSA (CSAI 29.9/hr). A titration study was conducted and bilevel positive airway pressure spontaneous/timed (BPAP ST) 10/6 cmH2O with a backup rate of 12 breaths per minute was utilized further resolving his SDB and daytime sleepiness. After months of BPAP ST therapy, he presented to an urgent care with symptoms of somnolence, emesis, and nystagmus of the left eye. Magnetic resonance imaging of the brain revealed a 2 cm herniation of the cerebellar tonsils indicating CM type 1. Neurosurgery performed surgical decompression without complication. Post-operative PSG indicated significant improvement of OSA (oAHI of 3.45/hr) and resolution of CSA (0.9/hr). BPAP ST therapy was discontinued with the resolution of his daytime sleepiness and SDB. Conclusion This case demonstrates a patient with severe OSA and CSA due to an undiagnosed CM type 1. OSA and CSA are associated with CM; however, residual OSA typically exists status post decompression and can require positive airway pressure therapy for treatment. Our case demonstrates the need for consideration of CM in patients with complex sleep apnea and that surgical decompression can improve both OSA and CSA in these patients. Support (If Any)

Modern approaches to visual rehabilitation of patients with neuromotor disorde

Background. Approximately 50 % of children with cerebral palsy have vision problems, manifested in strabismus, impaired eye mobility, refractive errors, nystagmus development and partial atrophy of the optic nerve.The aim: to present a clinical case of combined correction of myopia and divergent strabismus in a patient with cerebral palsy (CP).Materials and methods. A clinical case of combined correction of myopia and divergent strabismus in a patient with cerebral palsy is presented. General anesthesia was used to perform a two-stage treatment under one anesthesia: the first stage – laser myopia correction by femtosecond extraction of the lenticule through a small access (SMILE) to both eyes, the second stage was the strabismus correction by performing tenoscleroplasty of the external rectus muscle and resection of the internal rectus muscle of both eyes. The sequence of stages is due to the relative traumatism of strabismus surgery, in some cases, accompanied by a reaction from the bulbar conjunctiva and the cornea in the form of edema, which, during subsequent femtosecond vision correction, can affect the refractive result and worsen visual acuity in the postoperative period.Results. The performed treatment let significantly increase uncorrected visual acuity, achieve a correct and stable eye position, which became the basis for changing the vision nature from monocular to binocular.Conclusion. Thus, modern laser and surgical technologies in combination with an adequate anesthesia allow rehabilitating patients as much as possible in a short time, even with severe forms of cerebral palsy, and significantly improving the quality of life.

Eye movements elevate crowding in idiopathic infantile nystagmus syndrome.

Idiopathic infantile nystagmus syndrome is a disorder characterised by involuntary eye movements, which leads to decreased acuity and visual function. One such function is visual crowding – a process whereby objects that are easily recognised in isolation become impaired by nearby flankers. Crowding typically occurs in the peripheral visual field, although elevations in foveal vision have been reported in congenital nystagmus, similar to those found with amblyopia. Here, we examine whether elevated foveal crowding with nystagmus is driven by similar mechanisms to those of amblyopia – long-term neural changes associated with a sensory deficit – or by the momentary displacement of the stimulus through nystagmus eye movements. A Landolt-C orientation identification task was used to measure threshold gap sizes with and without either horizontally or vertically placed Landolt-C flankers. We assume that a sensory deficit should give equivalent crowding in these two dimensions, whereas an origin in eye movements should give stronger crowding with horizontal flankers given the predominantly horizontal eye movements of nystagmus. We observe elevations in nystagmic crowding that are above crowding in typical vision but below that of amblyopia. Consistent with an origin in eye movements, elevations were stronger with horizontal than vertical flankers in nystagmus, but not in typical or amblyopic vision. We further demonstrate the same horizontal elongation in typical vision with stimulus movement that simulates nystagmus. Consequently, we propose that the origin of nystagmic crowding lies in the eye movements, either through image smear of the target and flanker elements or through relocation of the stimulus into the peripheral retina.

Ictal Lid Movements: Blinks and Lid Saccades

ABSTRACT Two types of lid movements, blinks and lid saccades, have discrete kinematic properties and physiology. These differences are reflected in distinct phenomenology of disorders affecting their neural substrate. Proof of this principle was seen in two patients, one with parietal lobe epilepsy and the other with temporal lobe epilepsy. The lid movements in the patient with parietal lobe epilepsy were rhythmic, yoked, and had a rapid upward component that instantaneously followed a slow downward drift. These cyclic movements strikingly resembled nystagmus, but unlike typical eye nystagmus, the rapid upward component was pathological and seemed to involve a saccadic mechanism. We suggest the terms “ictal lid saccades” or “ictal lid nystagmus” to describe such a phenomenon. In contrast, the patient with temporal lobe epilepsy had ipsilateral lid movements with rapid downward trajectories resembling reflex or spontaneous blinks. The term “ictal blink” is appropriate for this phenomenon.

Estimulação elétrica neural transcutânea (tens) na paroxismia do tronco cerebral: relato de caso

INTRODUÇÃO: A paroxismia de tronco encefálico, descrita em pacientes com esclerose múltipla (EM), caracteriza-se por episódios rápidos de vertigem e nistagmos evocados por movimentos cefálicos. A neuromodulação tem apresentado sucesso terapêutico em várias disfunções da EM, mas ainda não foi utilizada na paroxismia. OBJETIVO: Avaliar o efeito aditivo da neuromodulação por estimulação elétrica neural transcutânea (TENS) na musculatura periocular em paciente com EM e paroxismia de tronco encefálico não responsiva à reabilitação clássica associada à medicação. MATERIAL E MÉTODOS: Avaliação do nistagmo com videonistagmógrafo, da sensibilidade cutânea facial com estesiômetro, do blefaroclônus por gravação em vídeo e da sensação dolorosa de forma subjetiva (descrição pessoal da paciente); execução de 10 sessões consecutivas semanais de exercícios oculares associados à TENS na musculatura do oblíquo inferior e reto lateral direitos. RESULTADO: Melhora da algia, do blefaroclônus, da vertigem e do nistagmo ocular direito. CONCLUSÃO: A neuromodulação com TENS parece ser uma terapia complementar válida para pacientes com EM e paroxismia de tronco não responsivos aos demais tratamentos clínicos, porém mais estudos são necessários para confirmar esse achado.

A reduced visual pathway response in infantile nystagmus syndrome

To investigate visual cortical responses in children with infantile nystagmus syndrome (INS) and the potential contribution of foveation periods. The medical records of children with INS who had visual evoked potential (VEP) recordings to reversing checkerboards and onset of horizontal gratings were reviewed retrospectively. VEP recordings underwent objective selective averaging for extraction of brief periods having consistent amplitude and timing with the stimulus presentation. VEP amplitude, latency, and signal-to-noise ratios (SNR) were compared to results from published age-matched controls under the same conditions. Relative foveation in INS subjects was determined from the proportion of time a video-oculography recording met eye position and velocity criteria. A total of 26 children met inclusion criteria. Selective averaging increased VEP amplitude and SNR in INS by 270%-420% compared to standard averaging (P<0.0001). The INS change in VEP response was greater for reversing checkerboard stimulation than horizontal-grating onset and was significantly greater than that in controls (P<0.001). Latency was not changed by selective averaging. Relative foveation was correlated with increasing VEP amplitude (P=0.02) and number of trials chosen for selective averaging (P<0.01). After selective averaging, relative foveation correlated with VEP amplitude to reversing checkerboards only (P=0.007). Nystagmus likely causes a reduced visual cortical response in children with INS. A significantly larger response can be extracted from brief periods during nystagmus eye movements, supporting the hypothesis that the INS visual system generates a larger cortical signal during brief foveation periods.

Ictal lid movements - Blinks and lid saccades

Two types of lid movements, lid saccades and blinks, have discrete kinematic properties and physiology. These differences are reflected in distinct phenomenology of disorders affecting their neural substrate. Proof of this principle was seen in two cases, one with parietal eyefield epileptiform discharges and the other with temporal lobe seizures. The lid movements in the patient with epileptiform discharges in the eyefield were rhythmic, yoked, and had rapid upward component that instantaneously followed slow downward drift. These cyclic movements strikingly resembled nystagmus, but unlike typical eye nystagmus, the rapid upward component was pathological and seemed to involve saccadic mechanism. We suggest terms “ictal lid saccade” or “ictal lid nystagmus” to describe such phenomenology. In contrast, the patient with temporal lobe seizures had ipsilateral lid movements with rapid downward trajectories resembling reflex or spontaneous blinks. The term “ictal blink” is appropriate for this phenomenology. Schematic organization of the underlying neural circuit for lid saccade (A) and blink (B). The caricature of trajectory of lid saccade (C) and blink (D). In the caricature of the lid saccade caricature, vertical lid position is schematized in blue color, while corresponding lid velocity is schematized in brown color. The bottom row schematized EMG activity from levator palpebrae (LP, green color) and orbicularis oculi (OO, light brown color). In schematic in panel C, D, the x-axis always represents time, and schematized EMG activity is temporally matched with schematized lid position and lid velocity.

The Reliance on Vestibular Information During Standing Balance Control Decreases With Severity of Vestibular Dysfunction.

The vestibular system is involved in gaze stabilization and standing balance control. However, it is unclear whether vestibular dysfunction affects both processes to a similar extent. Therefore, the objective of this study was to determine how the reliance on vestibular information during standing balance control is related to gaze stabilization deficits in patients with vestibular dysfunction. Eleven patients with vestibular dysfunction and twelve healthy subjects were included. Gaze stabilization deficits were established by spontaneous nystagmus examination, caloric test, rotational chair test, and head impulse test. Standing balance control was assessed by measuring the body sway (BS) responses to continuous support surface rotations of 0.5° and 1.0° peak-to-peak while subjects had their eyes closed. A balance control model was fitted on the measured BS responses to estimate balance control parameters, including the vestibular weight, which represents the reliance on vestibular information. Using multivariate analysis of variance, balance parameters were compared between patients with vestibular dysfunction and healthy subjects. Robust regression was used to investigate correlations between gaze stabilization and the vestibular weight. Our results showed that the vestibular weight was smaller in patients with vestibular dysfunction than in healthy subjects (F = 7.67, p = 0.011). The vestibular weight during 0.5° peak-to-peak support surface rotations decreased with increasing spontaneous nystagmus eye velocity (ρ = −0.82, p < 0.001). In addition, the vestibular weight during 0.5° and 1.0° peak-to-peak support surface rotations decreased with increasing ocular response bias during rotational chair testing (ρ = −0.72, p = 0.02 and ρ = −0.67, p = 0.04, respectively). These findings suggest that the reliance on vestibular information during standing balance control decreases with the severity of vestibular dysfunction. We conclude that particular gaze stabilization tests may be used to predict the effect of vestibular dysfunction on standing balance control.

Three-Dimensional Computer Model of Benign Paroxysmal Positional Vertigo in the Semi-Circular Canal

Benign Paroxysmal Positional Vertigo (BPPV) is the most common vestibular disorder. In this paper we tried to investigate a model of the semi-circular canal (SCC) with parametrically defined dimension and full 3D three SCC from patient-specific 3D reconstruction. Full Navier-Stokes equations and continuity equations are used for fluid domain with Arbitrary-Lagrangian Eulerian (ALE) formulation for mesh motion. Fluid-structure interaction for fluid coupling with cupula deformation is used. Particle tracking algorithm has been used for particle motion. Velocity distribution, shear stress and force from endolymph side are presented for one parametric SCC and three patient-specific SCC. All models are used for correlation with the same experimental protocols with head moving and nystagmus eye tracking.

Progressive Cavitating Leukoencephalopathy in an Infant Baby: A Case Report

Cavitating leukoencephalopathy is a group of disorders caused by multiple mitochondria dysfunction syndrome (MMDS). Multiple genetic mutations have been identified in its etiology including a mutation in the IBA57 gene on chromosome 1q42. We present the case of a 5-month-old boy who was diagnosed with progressive cavitating leukoencephalopathy at King Faisal specialist Hospital, Riyadh city, Saudi Arabia. The patient presented with frequent excessive crying since birth. He also had a history of abnormal movement described as tonic spasm of the upper limbs for few second, delayed developmental milestones, and regression of the achieved milestones. Neurological examination of the patient was positive for horizontal eye nystagmus and optic nerve atrophy, exaggerated gag response, spastic tone that was more prevalent in the upper limbs, and bilateral clonus. The patient showed abnormal findings on MRI including cavitation and cystic leukodystrophy, and homozygosity mapping showed the IBA57 gene mutation. The patient died at the age of 7 months from progressive respiratory failure. MMDS is a rare condition, and according to available data, this case of MMDS is the first to be reported in Saudi Arabia and in the Gulf region.