Nystagmus: prevalence, classification, pathogenesis. (Literature review)

The article provides information on the prevalence of nystagmus in the Russian Federation and the world. However, the lack of standards for data collection and the very understanding of the definition of optical nystagmus is the reason for the variation in prevalence values in different sources. Additionally, the article presents various classifications of nystagmus. Currently, there are many different classifications, and the most commonly used examples are given. The classification of eye movement disorders and strabismus, adopted by the working group in 2001 (Classification of Eye Movement Abnormalities and Strabismus CEMAS), is used worldwide. In our country, the most popular was the classification proposed by E.S. Avetisov (2001). Various sources have suggested quite contradictory data on the nature of the onset and the mechanism of development of nystagmus. Recently, the issues related to the pathogenesis of nystagmus have been revised. The theories that existed at the end of the last century were not substantiated in modern works. The pathogenesis of optic nystagmus remains less studied due to its complexity and ambiguity. The investigations continue to find the relationship between the pathology of the central nervous system and functional disorders of visual functions. The question of the relationship between visual acuity and nystagmus remains unclear. Does a decrease in vision cause nystagmus? How do oscillatory movements in nystagmus affect visual functions? This article encompasses the main areas of this issue. However, despite a significant step in understanding the causes of the development of nystagmus, this pathology remains insufficiently studied. This prompts many researchers and practicing doctors to study its pathogenesis further

Infranuclear Eye Movement Disorders

Infranuclear motility disorders are such of the cranial nerves, the extraocular muscles or changes in the orbit but definitely peripheral to the nuclei of the cranial nerves. Characteristic are movement deficits, a compensatory head posture and the pattern of incomitancy. The secondary angle of deviation is usually larger than the primary. Combined pareses suggest a lesion in the cavernous sinus, orbital apex or a multilocular event. It is essential to rule out supranuclear disorders, especially if the motility deficit is atypical. For clarification, an individual risk assessment is recommended, paying particular attention to risk factors.

Intrarater and Interrater Reliability of Dynamic Gait Index in Post Stroke Patients With Eye Movement Disorders

The authors have requested that this preprint be withdrawn due to erroneous posting.

Spinocerebellar Ataxia Type 28 in a Chinese Pedigree: A Case Report and Literature Review

Spinocerebellar ataxia (SCA) is a common neurogenetic disease, which mainly manifests as ataxia of posture, gait and limbs, cerebellar dysarthria, cerebellar and supranuclear eye movement disorders. It is found that SCA is a kind of progressive neurodegenerative disease including many subtypes, which is mainly mapped to two genetic patterns as: autosomal dominant cerebellar ataxia (ADCA) and autosomal recessive cerebellar ataxia (ARCA). Molecular genetic diagnosis functions as a necessity in its clinical diagnosis and treatment. In our previous clinical work, we found a family with ataxia who presented a c.1852A > G missense mutation in the exon region of AFG3L2 gene by whole exome sequencing (WES) and Sanger validation. Spinocerebellar ataxia type 28 (SCA28) was suspected, which was not reported in the previous literature. We here report the case and review the literature.

Intrarater and Interrater Reliability of Dynamic Gait Index in Post Stroke Patients With Eye Movement Disorders

Background: The Dynamic Gait Index is a useful scale that has been evaluated for its reliability in patients with vestibular disorder, elderly people and, in chronic stroke population but its reliability has not been evaluated yet in sub-acute stroke patients with eye movement disorders. So the purpose of this study was to evaluate the intra-rater and inter-rater reliability of the Dynamic gait index to measure the dynamic balance, gait and risk of fall in sub-acute stroke population with eye movement disorders.Methods: A total of 30 (18 male, 12 females) stroke patients in the sub-acute phase suffering from eye movement disorders were recruited for this reliability study. Two experienced Physical therapists assessed the intra-rater and inter-rater reliability of the Dynamic gait index in two testing sessions three days apart. In the later session, two raters assessed the patients’ performance simultaneously on the Dynamic gait index. Data analysis was done at 95% confidence interval using the intra-class correlation coefficient (ICC2, 1). A significance level was set at P-value <0.05.Results: Mean tests scores by rater 1 in the first and second assessment were 17.4±2.04 and 18.0±2.05. Mean tests score by rater 2 in the second assessment were 18.6±2.06. Intra-rater (ICC=0.86, CI=0.73-0.93) and inter-rater (ICC=0.91, CI=0.83-0.96) reliability of total DGI scores was found good to excellent while intra-rater (ICC=0.73-0.91) and inter-rater (ICC=0.73-0.93) reliability of individual items of DGI scores were ranged from moderate to good. Item 8 (steps) showed lowest reliability (ICC=0.73). The significant difference was seen in total and individual scores (P<0.001) of DGI scale in both intra-rater and inter-rater reliability.Conclusions: The Dynamic gait index is found clinically a reliable tool to objectively measure dynamic balance, gait and risk of fall in sub-acute stroke individuals with eye movement disorders. The intra-rater and inter-rater reliability of the total DGI scores was found good to excellent; whereas intra-rater and inter-rater reliability for individual items of DGI were varied from moderate to good.

Ocular manifestations of Parkinson disease

Background: Parkinson's disease (PD) is the second most common neurodegenerative disorder. We aimed to review both the disease and the drug-related ocular manifestations of PD. Methods: In this manuscript, we have reviewed and summarized existing literature on the ocular manifestations and drug-related complications of PD. We have also discussed the use of current noninvasive imaging techniques, such as optical coherence tomography (OCT), for the early diagnosis and monitoring of PD. Results: Impaired color vision, reduced stereopsis, reduced contrast sensitivity, pupillary abnormalities, eye movement disorders, convergence insufficiency, dry eye syndrome, glaucoma, visual dysfunctions, retinal abnormalities, and drug-related side effects were among the listed ocular manifestations of PD. There is a large knowledge gap regarding the type of glaucoma affecting PD patients—whether it is open-angle or other types. Further case studies and long-term follow-ups during PD progression are necessary to fill this gap. Patient compliance with follow-up visits for more visual field tests and OCT during PD progression may become problematic when dementia and cognitive impairment occur. Conclusions: There is a general need for clinicians to perform further tests and more visual examinations to rule out ocular manifestations. Furthermore, additional clinical trials are needed to further evaluate the use of different types of OCT findings as biomarkers of PD progression. This would aid in early diagnosis and in delaying disease progression, if treated promptly.