Hereditary congenital nystagmus and gaze-holding failure: The role of the neural integrator

Neurology ◽  
1993 ◽  
Vol 43 (9) ◽  
pp. 1741-1741 ◽  
Author(s):  
L. F. Dell'Osso ◽  
B. M. Weissman ◽  
R. J. Leigh ◽  
L. A. Abel ◽  
N. V. Sheth
Keyword(s):  
Congenital Nystagmus ◽  
Neural Integrator ◽  
Gaze Holding

The role of vision on postural strategy evaluated in patients affected by congenital nystagmus as an experimental model

1999 ◽  
Vol 9 (6) ◽  
pp. 445-451
Author(s):  
S. Di Girolamo ◽  
W. Di Nardo ◽  
A. Cosenza ◽  
F. Ottaviani ◽  
A. Dickmann ◽  
...  
Keyword(s):  
Visual System ◽  
Postural Control ◽  
Visual Stimulus ◽  
Postural Balance ◽  
Visual Cues ◽  
Normal Subjects ◽  
Congenital Nystagmus ◽  
Dynamic Posturography ◽  
Normal Controls

The role of vision in postural control is crucial and is strictly related to the characteristics of the visual stimulus and to the performance of the visual system. The purpose of this investigation was to evaluate the effects of chronically reduced visual cues upon postural control in patients affected by Congenital Nystagmus (CN). These patients have developed since birth a postural strategy mainly based on vestibular and somatosensorial cues. Fifteen patients affected by CN and 15 normal controls (NC) were enrolled in the study and evaluated by means of dynamic posturography. The overall postural control in CN patients was impaired as demonstrated by the equilibrium score and by the changes of the postural strategy. This impairment was even more enhanced in CN than in NC group when somatosensorial cues were experimentally reduced. An aspecific pattern of visual impairment and a pathological composite score were also present. Our data outline that in patients affected by CN an impairment of the postural balance is present especially when the postural control relies mainly on visual cues. Moreover, a decrease in accuracy of the somatosensory cues has a proportionally greater effect on balance than it has on normal subjects.

Role of Cerebellum in Gaze-Holding Disorders

2021 ◽  
pp. 1809-1825
Author(s):  
Neel Fotedar ◽  
Fajun Wang ◽  
Aasef G. Shaikh
Keyword(s):  
Gaze Holding

Gaze Holding and the Neural Integrator

2015 ◽  
pp. 360-385 ◽  
Author(s):  
R. John Leigh ◽  
David S. Zee
Keyword(s):  
Tonic Contraction ◽  
Laboratory Evaluation ◽  
Neural Integrator ◽  
Compensatory Mechanisms ◽  
Interstitial Nucleus Of Cajal ◽  
The Neural Network ◽  
Clinical Disorders ◽  
Gaze Holding ◽  
Prepositus Hypoglossi ◽  
Alexander’S Law

This chapter reviews the neural network that temporally integrates premotor, velocity-coded signals to achieve tonic contraction of the extraocular muscles to hold the eyes at an eccentric position in the orbits. The mechanical properties of the eye and its supporting tissues are quantified and related to the pulse-slide-step neural command for a saccadic change in eye position. The anatomical substrate and neuropharmacology of the neural integrator is reviewed, including nucleus prepositus hypoglossi, interstitial nucleus of Cajal and cerebellum. Mathematical and animal models for the neural integrator are discussed, addressing points about how a leaky or unstable integrator may arise. Clinical and laboratory evaluation of gaze holding is summarized. Effects of experimentally inactivating the neural integrator are compared with clinical disorders affecting gaze holding, including a discussion of the pathogenesis of gaze-evoked nystagmus and Alexander’s law. Compensatory mechanisms for a leaky neural integrator are discussed, including centripetal, rebound, and gaze-evoked nystagmus.

The role of ocular oscillations upon visually dependent postural stabilization in patients affected by congenital nystagmus

2000 ◽  
Vol 10 (4-5) ◽  
pp. 201-206
Author(s):  
Gustavo Savino ◽  
Anna Dickmann ◽  
Fabrizio Ottaviani ◽  
Walter Di Nardo ◽  
Luigi Scullica ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Postural Control ◽  
Visual Cues ◽  
Normal Subjects ◽  
Congenital Nystagmus ◽  
The Gaze ◽  
Postural Stabilization ◽  
Normal Controls ◽  
Better Than

Visually dependent postural stabilization decreases as a consequence of a long-standing reduction of visual cues in patients affected by congenital nystagmus. The aim of the present study was to verify whether the changes in postural control in this group of patients are due to ocular oscillations or to reduced visual acuity. Therefore, postural control was evaluated when the nystagmus was blocked by the blocking position or by prisms and compared with the postural score observed in a group of normal controls whose visual acuity had been artificially reduced to the same level as that of the patients using Bangerter's filters. The results show a statistically significant improvement of visually dependent postural stabilization when ocular oscillations are inhibited either by the gaze blocking position or by prisms. They also show that postural control in normal subjects with Bangerter's filters is reduced, but is still significantly better than that observed when ocular oscillations are inhibited in patients affected by congenital nystagmus. Our data strongly support the role of ocular oscillations in visually dependent postural control, since postural impairment recovered under any condition in which ocular oscillations were abolished, despite differences in visual acuity. Our data also show that reduced visual acuity decreases visually dependent postural control to a lesser degree than ocular oscillations. This could be due to the fact that ocular oscillations are a disturbing input, usually inhibited centrally, in order to avoid oscillopsia. This mechanism is probably responsible for the reduced role of visual cues in the postural control in this group of patients. The reduction of visual acuity, by comparison, merely causes a decrease in visual cues, depending on the degree of visual loss. It can be concluded that the impaired postural control in patients affected by congenital nystagmus is mainly due to ocular oscillations, with reduced visual acuity creating a secondary effect.

Role of the vestibular commissure in gaze-holding in the cat

Neuroreport ◽  
1994 ◽  
Vol 5 (12) ◽  
pp. 1421-1424 ◽  
Author(s):  
P. Mettens ◽  
G. Cheron ◽  
E. Godaux
Keyword(s):  
Gaze Holding

scholarly journals Role of contact lenses in the management of congenital nystagmus.

1983 ◽  
Vol 67 (12) ◽  
pp. 834-836 ◽  
Author(s):  
E. D. Allen ◽  
P. D. Davies
Keyword(s):  
Contact Lenses ◽  
Congenital Nystagmus

scholarly journals A small gene sequencing panel realises a high diagnostic rate in patients with congenital nystagmus following basic phenotyping

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luke O’Gorman ◽  
Chelsea S. Norman ◽  
Luke Michaels ◽  
Tutte Newall ◽  
Andrew H. Crosby ◽  
...  
Keyword(s):  
Diagnostic Yield ◽  
Congenital Nystagmus ◽  
High Diagnostic Yield ◽  
Infantile Nystagmus ◽  
Targeted Ngs ◽  
Causal Variants ◽  
Next Generation Sequencing Ngs ◽  
Changing Role ◽  
Generation Sequencing

Abstract Nystagmus is a disorder of uncontrolled eye movement and can occur as an isolated trait (idiopathic INS, IINS) or as part of multisystem disorders such as albinism, significant visual disorders or neurological disease. Eighty-one unrelated patients with nystagmus underwent routine ocular phenotyping using commonly available phenotyping methods and were grouped into four sub-cohorts according to the level of phenotyping information gained and their findings. DNA was extracted and sequenced using a broad utility next generation sequencing (NGS) gene panel. A clinical subpanel of genes for nystagmus/albinism was utilised and likely causal variants were prioritised according to methods currently employed by clinical diagnostic laboratories. We determine the likely underlying genetic cause for 43.2% of participants with similar yields regardless of prior phenotyping. This study demonstrates that a diagnostic workflow combining basic ocular phenotyping and a clinically available targeted NGS panel, can provide a high diagnostic yield for patients with infantile nystagmus, enabling access to disease specific management at a young age and reducing the need for multiple costly, often invasive tests. By describing diagnostic yield for groups of patients with incomplete phenotyping data, it also permits the subsequent design of ‘real-world’ diagnostic workflows and illustrates the changing role of genetic testing in modern diagnostic workflows for heterogeneous ophthalmic disorders.

Acquired nystagmus

2020 ◽  
Vol 81 (11) ◽  
pp. 1-8
Author(s):  
Jesse Panthagani ◽  
Jasvir Virdee ◽  
Trystan MacDonald ◽  
Alice Bruynseels ◽  
Ruchika Batra
Keyword(s):  
Visual Target ◽  
Neural Integrator ◽  
The Gaze ◽  
Ocular Reflex ◽  
Surrounding Environment ◽  
Gaze Holding ◽  
Illusory Movement ◽  
Vestibulo Ocular Reflex ◽  
Acquired Nystagmus ◽  
Underlying Pathology

Nystagmus is the repetitive to and fro movement of the eyes, which may be physiological or pathological. The movements can be horizontal, vertical, torsional or a combination of these movements. It starts by a slow movement of the eye away from the visual target. The second movement brings the eye back to the visual target. If this second movement is quick, the nystagmus is called jerk nystagmus. If the second movement is slow, the nystagmus is said to be pendular. Maintaining steady gaze is dependent upon visual fixation, the vestibulo-ocular reflex and the gaze-holding neural integrator system. Pathological nystagmus typically presents with the symptom of oscillopsia, which is the illusory movement of the surrounding environment. Nystagmus that develops outside of early infancy is termed acquired nystagmus. There may be serious underlying pathology that will require further investigation and management. This article reviews the terminology, pathophysiology, causes and treatment of acquired nystagmus.

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