Abnormal Eye Movements Research Articles

Eye movement study in essential tremor patients and its clinical correlates.

Essential tremor (ET) encompasses a wide spectrum of motor and non-motor features. Eye movement abnormalities were first reported two decades ago as an atypical finding in ET. Today, a growing number of publications about eye movement abnormalities in neurodegenerative diseases have helped understand their pathophysiology and the basis of their phenotypic variability. Thus, addressing such aspect in ET may disentangle, based on the oculomotor network abnormalities, the dysfunctional brain pathways in ET. In this study, we aimed to describe neurophysiological eye movement abnormalities in ET and their clinical correlates in terms of cognition and other associated clinical signs. We conducted a cross-sectional study in a tertiary neurology referral center including consecutive ET patients and cognitively normal healthy controls (HC) matched for age and sex. The study protocol included the assessment of voluntary horizontal saccades, smooth pursuit, anti-saccades and saccadic intrusions. We assessed the associated motor signs, cognitive functions and the presence of rapid eye movement disorder (RBD). Sixty-two ET patients and 66 HC were enrolled in the study. Eye movement examination showed significant abnormalities in comparison with HC (46.7% vs 20%, p = 0.002). Prolonged saccadic latency (38.7%, p = 0.033) and altered smooth pursuit (38.7%, p = 0.033) were the most common abnormalities in ET patients. Anti-saccadic errors (16% vs 0% in HC, p = 0.034) correlated with the presence of rigidity (p = 0.046), bradykinesia (p = 0.001), cognitive dysfunction (p = 0.006), executive dysfunction (p = 0.0002), apraxia (p = 0.0001), altered verbal fluency (p = 0.013) and altered backward digit span (p = 0.045) along with the presence of RBD (p = 0.035). Square-wave jerks (11.5% vs 0% in HC, p = 0.0024) correlated with rest tremor. A distinctive phenotype of ET could emerge out of this study characterized by anti-saccadic errors and a sub-cortical cognitive profile, consecutive to the disruption of the cerebello-thalamo-cortical loop. Patients with anti-saccadic errors could be cognitively vulnerable and in need of a close monitoring of their cognitive efficiency during the disease's progression. They may as well convert to Parkinson disease if they present with parkinsonism, RBD and square-wave jerks and require, consequently, a close observation of their motor progression.

New insights into cerebellar dysfunction in patients with delusional disorder: A systematic review

IntroductionThe cerebellum has been implicated in cognitive, affective and motor functions, including emotion regulation, executive control and sensorimotor processing. In schizophrenia, cerebellar dysfunction has been associated with treatment resistance and clinical features. However, few studies have been focused on delusional disorder (DD).ObjectivesOur main purpose was to review the evidence available on cerebellum abnormalities and dysfunctions in patients with DD.MethodsA systematic review was conducted through PubMed, Scopus and ClinicalTrials.gov (inception-June 2022) according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) directives. The following search terms were used: cerebellum OR cerebellar AND (“delusional disorder” AND paranoia). Reference lists from included studies were hand-checked to find other potential relevant papers.ResultsSix studies were included from a total of 119 retrieved records (PubMed: 52, Scopus: 66, ClinicalTrials.gov: 1). Study 1:Patients with DD somatic type (n=14) presented a decreased gray matter volume in cerebellar lobules compared to healthy controls (HC) (n=32, left lobule VIIIa) and non-somatic DD (n=18, lobule V). Cerebellar volumes did not seem to differ between HC and non-somatic DD. Study 2:Abnormalities of voluntary saccadic eye movements, linking frontal and cerebellar functions, were found in DD patients (n=34) compared to HC (n=40). Study 3: Abnormal smooth pursuit eye movements in DD (n=15) compared with HC (n=40) and similar to schizophrenia (n=40). Case reports (n=3): DD associated with Dandy-Walker variant (partial vermian hypoplasia), unruptured intracerebral aneurysm of basilar artery, and megacisterna magna.ConclusionsCerebellar deficits in patients with DD has been reported, particularly in those presenting somatic delusional contents.Disclosure of InterestNone Declared

視線追跡機能搭載型VRヘッドセットによる眼球運動検査装置の開発

Recording eye movement at a patient's first visit to primary care is critical, because abnormal eye movement findings can disappear, accompanied by a lessening of symptoms. In addition, sharing such data with an expert institution can support a precise diagnosis. However, recording devices such as ENG and VOG are relatively expensive to introduce to private clinics. In addition, the series of eye movement examinations can take a relatively long time, potentially delaying other medical care. Recent advances in virtual reality (VR) technology have led to the development of VR goggles, which can project 3D images and also record eye movements. This kind of device can be a useful tool for the development of a novel and affordable instrument for private clinics. We have been participating in the development of a VR goggle-based VOG. This device can record ordinary sequential examinations automatically, to save time. At the same time, we are also developing an advanced model for specialists. In this manuscript, we introduce our novel VOG equipment. In addition, we discuss the possibility of future applications.

Reflections on “Contact” and “The Gaze” in Clinical Practice

GoalsThis article explores the semiological value of contact and of the gaze in clinical practices. It questions the subjectivity involved in the caregiver/patient relationship and in nosography. MethodologyThe authors examine the place of the gaze based on writings of 19th century alienists. Then, they question the clinician's subjective experience – through the concepts of “sentiment” (Binswanger, Minkowski) and “praecox Gefühl” (Rümke) from the accounts of early stages of the clinical encounter. ResultsThe gaze plays a specific role in the early stages of the clinical encounter, especially in the landscape of schizophrenia. A draft classification of different types of gazes (off-center gaze, white gaze, ecstatic gaze, black gaze) is proposed, then nuanced. DiscussionAny attempt to classify the gaze leads to the deconstruction of any fixed typology. The gaze resists verbalization and even meaning, and in this, belongs to the dimension of anguish, an essential affect in a practice that does not seek to do away with relationship. ConclusionAt a time of increasing research in “eye movement abnormalities” in schizophrenia, it seems essential to renew our interest in the relational and therefore subjective – dimension as a specificity in clinical psychiatry. The gaze, then, would be this area without a place, this primary area of contact where relationship begins or not.

Ocular motor impairment in early-stage multiple sclerosis: a video-oculography assessment

BackgroundEye movement disorders in multiple sclerosis (MS) are frequently misdiagnosed and frequently overlooked during clinical examinations. Even at a preclinical state, these defects frequently cause impairment and weariness.MethodsWe conducted a cross-sectional observational study including 20 individuals with a confirmed MS diagnosis. The inclusion criteria were an EDSS score of 4 or less and a 6-month interval between the last relapse and enrolment. As part of the MS assessment, a routine ORL, neurology exam, eye exam, assessment of eye movement using Ulmer’s videonystagmography battery tests, and routine brain MRI were performed on the patient.ResultsA total of 75% of the patients in our series are female, with a mean age of 39 years and a range of 24 to 59 years. The average age of MS onset is 32 years. The relapsing-remitting type of multiple sclerosis (RRMS) accounts for 95% of all cases. There is only a single case of secondary progressive disease course (SPMS). Principal VNG manifestations are related to subclinical eye movements abnormalities. Rotatory vertigo caused by vestibular dysfunction was less prevalent than other balance disorders. There were found to be two types of nystagmus: pendular and central positional nystagmus.Discussion and conclusionVNG is sensitive for detecting vestibular system dysfunction in MS patients. It is also beneficial for diagnosing subtle eye movement abnormalities that are usually overlooked.

An Overview of Genes Involved in the Pure Joubert Syndrome and in Joubert Syndrome-Related Disorders (JSRD)

AbstractJoubert syndrome (JS) is a rare autosomal recessive disease characterized by a peculiar brain malformation, hypotonia, ataxia, developmental delay, abnormal eye movements, and neonatal breathing abnormalities. This picture is often associated with variable multiorgan involvement, mainly of the retina, kidneys and liver, defining a group of conditions termed syndrome and Joubert syndrome-related disorders (JSRD). Currently, more than 30 causative genes have been identified, involved in the development and stability of the primary cilium. Correlations genotype–phenotype are emerging between clinical presentations and mutations in JSRD genes, with implications in terms of molecular diagnosis, prenatal diagnosis, follow-up, and management of mutated patients.

Eye Movement Abnormalities Can Distinguish First-Episode Schizophrenia, Chronic Schizophrenia, and Prodromal Patients From Healthy Controls.

This study attempts to replicate in a Chinese population an earlier UK report that eye movement abnormalities can accurately distinguish schizophrenia (SCZ) cases from healthy controls (HCs). It also seeks to determine whether first-episode SCZ differ from chronic SCZ and whether these eye movement abnormalities are enriched in psychosis risk syndrome (PRS). The training set included 104 Chinese HC and 60 Chinese patients with SCZ, and the testing set included 20 SCZ patients and 20 HC from a UK cohort. An additional 16 individuals with PRS were also enrolled. Eye movements of all participants were recorded during free-viewing, smooth pursuit, and fixation stability tasks. Group differences in 55 performance measures were compared and a gradient-boosted decision tree model was built for predictive analyses. Extensive eye-movement abnormalities were observed in patients with SCZ on almost all eye-movement tests. On almost all individual variables, first-episode patients showed no statistically significant differences compared with chronic patients. The classification model was able to discriminate patients from controls with an area under the curve of 0.87; the model also classified 88% of PRS individuals as SCZ-like. Our findings replicate and extend the UK results. The overall accuracy of the Chinese study is virtually identical to the UK findings. We conclude that eye-movement abnormalities appear early in the natural history of the disorder and can be considered as potential trait markers for SCZ diathesis.

Endocrine manifestations in Joubert syndrome—literature review

<abstract> <p>Joubert syndrome (JS) is a heterogeneously inherited, rare, autosomal recessive disorder characterised by neonatal breathing dysregulation, developmental delay, hypotonia, abnormal eye movements and a distinctive cerebellar and brainstem malformation called the molar tooth sign (MTS). Patients with JS may develop hypothalamic-pituitary dysfunction, leading to growth hormone deficiency, hypothyroidism, adrenal insufficiency and hypogonadism. This review summarizes the screening, diagnosis, and management of these conditions in JS.</p> </abstract>

Möbius Syndrome and Cerebellar Dysplasia: A Novel Association

We present a case of a 4-month-old infant with abnormal eye movements, unusual flat facies, and lack of expression during crying, clinically diagnosed with Möbius syndrome. MR imaging demonstrated absent facial and abducens nerves. A dysplastic right cerebellar hemisphere containing a cleft and multiple clustered cysts was also observed, which, to our knowledge, represents the first documented case of an association between Möbius syndrome and cerebellar dysplasia. A review of pertinent literature is provided.

Eye tracking as a tool for assessing social cognition: A case-control study comparing patients with psychosis and healthy controls

Background: Eye movement dysfunction is a common abnormality in Schizophrenia and other psychotic disorders. Various eye movement paradigms can be used to measure predefined parameters using eye trackers. The current study intends to understand the eye movement characteristics in individuals suffering from psychosis using newer eye-tracking instruments with better precision. Methodology: In this study, we included 29 individuals meeting the diagnostic criteria for schizophrenia spectrum and other psychotic disorders based on the clinical assessment as per Diagnostic and Statistical Manual of Mental Disorders, 5th Edition along with 29 age- and gender-matched healthy controls and measured various eye tracking parameters using a Tobii Pro Spectrum. We compared the eye-tracking parameters between both groups. Results: There were significant differences between the groups in the free-viewing task. The average duration of fixations was higher, whereas the number of fixations and total amplitude of saccades was found to be reduced in the patient group. The peak velocity of the first saccade was also seen to be reduced in the patient group. However, there were no abnormalities in the anti-saccade, predictive saccade, memory saccade, and smooth pursuit tasks. Eye movement parameters were also found to be significantly correlated with the cognitive task measurements. Conclusion: These findings confirm the presence of eye movement abnormalities in psychosis spectrum disorders and their role in cognitive deficits in psychosis. Altered free viewing may be linked to deficits in social cognition found in patients with schizophrenia.

Phenotypic spectrum of patients with Poretti-Boltshauser syndrome: Patient report of antenatal ventriculomegaly and esophageal atresia

Poretti-Boltshauser syndrome (PTBHS) is an autosomal recessive disorder characterized by cerebellar dysplasia with cysts and an abnormal shape of the fourth ventricle on neuroimaging, due to pathogenic variants in the LAMA1 gene. The clinical spectrum mainly consists of neurological and ophthalmological manifestations, including non-progressive cerebellar ataxia, oculomotor apraxia, language impairment, intellectual disability, high myopia, abnormal eye movements and retinal dystrophy.We report a patient presenting with ventriculomegaly on antenatal neuroimaging and a neonatal diagnosis of Type III esophageal atresia. She subsequently developed severe myopia and strabismus with retinal dystrophy, mild developmental delay, and cerebellar dysplasia. Genetic investigations confirmed PTBHS.This report confirms previous reports of antenatal ventriculomegaly in PTBHS patients and documents a so far unreported occurrence of esophageal atresia in PTBHS. We additionally gathered phenotype and genotype descriptions of published cases in an effort to better define the spectrum of PTBHS.

Cataract surgery outcomes in pediatric patients with systemic comorbidities.

The aim of the study was to evaluate the outcomes of cataract surgery in patients of the pediatric age group with systemic comorbidities. Medical records of 54 eyes (30 patients) of the pediatric age group with systemic comorbidities who had undergone cataract surgery in a tertiary-care center were reviewed. The following parameters were recorded: systemic comorbidity; toxoplasmosis, rubella, cytomegalovirus, herpes simplex, HIV (TORCH) profile, best spectacle-corrected visual acuity (BSCVA), strabismus, nystagmus, and cataract morphology. Thirty patients with a mean age of 55 months (9 months-14 years) were included. On average, every child was seen by three physicians, and the mean duration between the first visit to a physician and presentation to our center was 2.23 ± 0.67 years. The various causes for delay in referral include multiple referrals due to a lack of general anesthesia services in 78% of cases, a long waiting list at the referral hospital in 35% of cases, and a lack of awareness at the primary-care physician level in 50% of cases. The mean BSCVA at presentation was 1.4 logMAR (0.3 to 3 logMAR). The most common cataract morphology was that of zonular cataract (31.48%; 17/54). Strabismus and abnormal eye movements were observed in 27.7% (15/54) and 33.3% (18/54) of eyes, respectively. Various systemic associations were periventricular leukomalacia (12/30), Down's syndrome (6/30), seizure disorder (6/30), cardiac valvular anomalies (6/30), Marfan's syndrome (4/30), hypothyroidism (4/30), rubella (3/20), cytomegalovirus (3/20), cerebral palsy (2/30), nephrotic syndrome (2/30), Type 1 diabetes mellitus (1/30), microcephaly (1/30), cryptogenic West syndrome (1/30), congenital rubella syndrome (1/30), and Tourette syndrome (1/30). The mean postoperative corrected distance visual acuity (CDVA) at 2-year follow-up improved to 1.0 logMAR (0 to 3 logMAR). No postoperative complications were reported at the final follow-up. Around 70% of the parents reported improvement in their child's psychomotor skills. Intellectually impaired pediatric patients with cataract should be operated upon whenever there is a presence of infrastructure, and unnecessary delay in surgery should be avoided by referring the patient to higher centers. Even though objective improvement in visual acuity was suboptimal, there was definitely an improvement in the psychomotor skills of the patients.

Pelizaeus-Merzbacher disease-like disorder in an Indian girl with a missense variant in GJC2 gene

Pelizaeus-Merzbacher-like disease 1 (PMLD1) is a slowly progressive leukodystrophy that typically presents during the neonatal or early infantile period with nystagmus, commonly associated with hypotonia, delayed acquisition of motor milestones, speech delay and dysarthria. We present a 7-year-old female born to a nonconsanguineous marriage with developmental delay. On examination, she had 22 teeth, and nystagmus with pseudophakia. Neurological examination showed spasticity with increased deep tendon reflexes. On investigation, MRI of the brain done at 3 years showed hypomyelination. Targeted exome sequencing revealed a homozygous non-synonymous variation c.138C>G in exon 2 of the GJC2 gene. Sanger sequencing was done which showed the presence of a variant in the heterozygous state in both parents. PMLD1 should be suspected in any child presenting with diffuse hypomyelination with abnormal eye movements, especially in a girl child with PelizaeusMerzbacher disease phenotype with hypomyelination in the pons.

Serum levels of glial fibrillary acidic protein in patients with amyotrophic lateral sclerosis.

To compare serum levels of the astrocyte biomarker glial fibrillary acidic protein (GFAP) in patients with amyotrophic lateral sclerosis (ALS) and neurologically healthy controls and to analyze the relations between serum GFAP (sGFAP) and phenotype in ALS. We studied 114 ALS patients and 38 controls. sGFAP was quantified with single molecule array (Simoa) technology. In both ALS patients and controls, sGFAP moderately correlated with age. ALS patients had higher sGFAP levels compared to controls, but this yielded a weak discriminative performance (AUC=0.6198). In ALS, sGFAP was not associated with most of the motor phenotypic features, including site of onset, functional status, disease progression rate, disease stage, and indices of upper (UMN) and lower motor neuron (LMN) impairment. However, sGFAP negatively correlated with cognitive scores regarding ALS-nonspecific functions, particularly memory (r=-0.2082) and tended to be higher in ALS patients with eye movement abnormalities (p=0.0628). sGFAP also correlated with polysomnographic indices of oxygen desaturation (ODI; r=0.2639) and apnea-hypopnea (AHI; r=0.2858). In a multivariate analysis, sGFAP was negatively associated with survival (HR=1.005). Relevantly, we found a negative correlation between sGFAP and estimated glomerular filtration rate (eGFR; r=-0.3500). Our work provides neurochemical evidence of astrocyte involvement in ALS pathophysiology and particularly in the development of extra-motor manifestations (namely, cognitive - memory - impairment) and respiratory dysfunction. The negative correlation between sGFAP and eGFR has practical relevance and should not be disregarded in future investigations.

Etiological Factors of Opsoclonus Myoclonus Ataxia Syndrome: A Single Center Experience with Eight Children

Objective: Opsoclonus myoclonus ataxia syndrome (OMAS) is a rare neurological disorder characterized by acute/subacute onset multi-directional chaotic eye movements, accompanied by myoclonus and cerebellar ataxia; as well as sleep disturbance, cognitive dysfunction, and behavioral disturbance can be observed. Methods: We examined the information of eight patients (four females, four males) who applied to the hospital with OMAS between 2013 and 2020 from the medical records of the patients. Results: The median age of onset of the initial symptoms was 17.5 months (8-30 months). The most common initial complaints were abnormal eye movement and gait unsteadiness, respectively. Paraneoplastic OMAS was observed in three patients (37.5%), whereas idiopathic and infection-related OMAS was detected in three, and two patients, respectively. Conclusion: We emphasize that all symptoms of OMAS may not occur simultaneously, therefore comprehensive systemic investigations, and close observation should be made in patients with suspected OMAS.

Simultaneous cardio‐cerebral infarction in a dog

AbstractA 4‐year‐old, spayed, female, mix‐breed dog presented for acutely rolling to the left. She had developed an apathetic behaviour over the last 5 months and also recurrent urinary tract infections. On presentation, cardiac auscultation revealed a fast heart rate and premature beats. The dog was stuporous, with a head tilt to the left, abnormal eye position and movements and absent facial sensation on the left side of the head. Clinicopathologic analysis was consistent with hypothyroidism. Electrocardiography evaluation revealed an accelerated idioventricular rhythm interrupted by ventricular premature complexes. Postmortem examination revealed infarction of the right thalamus due to an occlusive thrombus associated with atherosclerosis, together with acute myocardial infarction of the left ventricular wall with an associated thrombus and atherosclerosis in a supplying coronary artery. This report illustrates a concurrent cardio‐cerebral infraction in a dog. Neurological and electrocardiographic abnormalities are explained, and the pathophysiology of the clinical signs is discussed.

Opsoclonus Myoclonus Syndrome and Supraventricular Tachycardia in a Pediatric Patient: A Case Report and Literature Review

Objective NA. Background Opsoclonus myoclonus syndrome (OMS) is a rare movement disorder in children often associated with an underlying neuroblastoma. In other cases, it is believed that the tumor is occult or there is another immune-stimulating precipitating event. Diagnosis can be difficult, requiring 3 of 4 criteria: opsoclonus or ocular flutter, myoclonus or ataxia, behavioral or sleep disturbances, and neuroblastoma. Prompt treatment of OMS is crucial to preventing permanent neurologic sequelae. In order to better characterize the clinical profile of this syndrome and its associated conditions, we present a case report of a 9 month old male with OMAS without an associated neuroblastoma and with new onset supraventricular tachycardia (SVT) and review the associated literature. Design/Methods NA. Results A 9-month-old male with a past medical history of macrocephaly, hypotonia, and developmental delay presented with abnormal eye and body movements starting one month prior. Due to concern for OMS, the patient underwent an extensive initial workup including CT neck, chest, abdomen, and pelvis and VHA/HMA levels, which were all within normal limits. The patient's spinal fluid revealed no evidence of paraneoplastic, autoimmune, or infectious processes. Per neurology recommendations, the patient was started on IVIG and dexamethasone. After his first IVIG infusion, the patient's abnormal movements worsened, and his heart rate increased into the 300s. The IVIG was discontinued. However, the patient continued to have recurring bouts of SVT, which was eventually controlled with digoxin. After resuming treatment with IVIG and dexamethasone, the patient's opsoclonus myoclonus symptoms began to improve. All additional metabolic labs resulted normal and the patient was discharged. Conclusions Because OMS can cause permanent developmental delay, prompt recognition and treatment of this syndrome is necessary. This is a unique case of OMAS without neuroblastoma, associated with recurrent bouts of SVT. Recognizing rare complications of OMS is crucial to improving medical management of its sequelae.

Multiple sclerosis and occlusive retinal vasculitis: A case series

AbstractPurpose: Retinal vascular changes are a common finding in patients with multiple sclerosis (MS). While simple peripheral retinal periphlebitis is by far the most frequent manifestation, a spectrum exists that ranges up to the presence of proliferative retinal vasculitis.Methods: Case series of four patients with occlusive retinal vasculitis.Results: Three patients presented with complaints of visual loss and ocular discomfort: a 26‐year‐old man presented with vitreous inflammation, vitreous haemorrhage, macular edema and papillitis; a 44‐year‐old woman presented with intermediate uveitis and macular edema; and a 25‐year‐old woman presented with granulomatous panuveitis, papillitis and foveolar serous detachment. A fourth patient was addressed because of abnormal eye movements detected during a work‐up for dizziness. Examination revealed bilateral internuclear ophthalmoplegia with adduction lag. He had no visual complaints other than subtle floaters in the left eye. Anterior segment examination showed no signs of inflammation, whereas vitreous snowballs were present. Fluorescein angiography revealed occlusive retinal vasculitis in all patients, resulting in active neovascularization in two patients with vitreous haemorrhage in one of them. All patients required retinal laser photocoagulation. Extensive work‐up revealed multiple sclerosis as the underlying disease in three patients; the remaining patient had already been diagnosed with MS at the time of presentation. Nevertheless, additional work‐up was performed in this patient to exclude other possible causes.Conclusions: Occlusive retinal vasculitis is a rare manifestation in patients with MS and may result in neovascularization, vitreous haemorrhage, retinal detachment and neovascular glaucoma. MS should therefore be considered in the differential diagnosis of ischemic retinal disease. In addition, one should be alert for signs of retinal vasculitis in patients with MS, as it can present with few or no symptoms.

Validation of a novel software‐based platform to extract oculometric measures

AbstractPurpose: Eye‐tracking systems are a valuable tool in the assessment of disorders by detecting eye movement abnormalities. However, current systems require lab settings, extraction of oculometric measures entails dedicated long sessions, and operation requires qualified personnel. Recently, a novel software‐based platform was developed, using a webcam, enabling the extraction of oculometric measures in a short test with seamless operation. The aim of this study was to validate this platform as compared with a validated eye‐tracker.Methods: 82 participants (51 females, age range 21–88) were evaluated with a software‐based platform (NeuraLight, Israel) in a 15‐minute eye‐tracking test. Participants were presented with different stimuli for various tasks. During the test, data from a validated eye‐tracker (Tobii Pro, Sweden) were captured. Correlations between oculometric measures captured by both methods were calculated using Pearson correlation. Observable information on demographic data was measured using Fisher information matrix.Results: Eye and gaze positions captured by the NeuraLight platform were highly correlated with eye‐tracker (r = 0.9–0.99, p < 0.01). Saccade and anti‐saccade latency, pro‐saccade and anti‐saccade error rates, position and velocity gain for all tasks were all highly correlated (r > 0.9, p < 0.01). Relative root mean square error of all measures in both methods was <0.1. Saccadic latency and fixation time were found to be in relation with participants' age.Conclusions: NeuraLight platform was significantly correlated with a validated eye‐tracker, providing high accuracy for eye and gaze positions and oculometric measures. Relation between oculometric measures and age was established. The platform can be implemented for assessment of eye movements in practice. Future studies are needed to use the platform in various conditions.

P006 Case study: Dancing eyes post COVID-19 vaccination

Abstract INTRODUCTION We describe a case of rapid eye movements in NREM sleep in a patient who had Guillain-Barre Syndrome (GBS) post AstraZeneca ( AZ) COVID-19 vaccine. This has not been reported previously. METHOD An 81-year-old male with recent diagnosis of GBS secondary to AZ COVID-19 vaccination was referred of investigation of sleep disordered breathing. A Level 2 PSG showed rapid eye movements in the absence of atonia predominantly during N1 sleep. A second study one month later confirmed the persistence of the eye movements. RESULTS Study 1 revealed mild supine and REM-predominant obstructive sleep apnoea (AHI = 14.9/hr) with reduced REM latency (44.5 minutes) & slow wave sleep (1.6%). Study 2 showed normal REM latency (61.5 minutes). REM indices were 0.33 per minute of N1 sleep and 0.12 for N2 sleep. REM density was 3% during N1 and 0.55% in N2. DISCUSSION COVID-19 vaccinations have been associated with various side-effects, some of which have been attributed to autoimmune response. A previous study on GBS patients reported sleep architecture abnormalities including sleep onset REM periods and abnormal eye movements in NREM sleep, during acute phase attributed to autonomic dysfunction and transitory hypocretin-1 transmission reduction . Our patient had almost completely recovered from GBS when we performed Study 1. We believe this to be the first case of abnormal eye movements in sleep being identified on polysomnography in a patient with GBS following AZ Covid-19 vaccination