Horizontal Gaze and Syndromes of the Pons

2014 ◽  
pp. 207-235
Author(s):  
Shirley H. Wray
Keyword(s):  
Facial Nerve ◽  
Medial Longitudinal Fasciculus ◽  
Caloric Test ◽  
Clinical Test ◽  
Internuclear Ophthalmoplegia ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Horizontal Gaze ◽  
The One ◽  
Gaze Palsy

covers deviations and disorders of horizontal gaze, which are so significantly linked to lesions of the pons that an emphasis on pontine signs is an important focus of this chapter. The pontine syndromes presented include a congenital case of horizontal gaze palsy and progressive scoliosis, and syndromes associated with adjacent tegmental structures, especially the paramedian reticular formation, the facial nerve, and the medial longitudinal fasciculus. A lesion of the medial longitudinal fasciculus causes internuclear ophthalmoplegia Examples are provided of internuclear ophthalmoplegia in childhood, combined unilateral conjugate gaze palsy and internuclear ophthalmoplegia, the one-and-a-half syndrome, and other variants. A case of bilateral horizontal gaze palsy permits discussion of the caloric test, one of the most widely used clinical test of the vestibulo-ocular reflex.

Impaired vestibular responses in internuclear ophthalmoplegia

Neurology ◽  
2017 ◽  
Vol 89 (24) ◽  
pp. 2476-2480 ◽  
Author(s):  
Seo-Young Choi ◽  
Hyo-Jung Kim ◽  
Ji-Soo Kim
Keyword(s):  
Vestibular Evoked Myogenic Potentials ◽  
Medial Longitudinal Fasciculus ◽  
Subjective Visual Vertical ◽  
Internuclear Ophthalmoplegia ◽  
Horizontal Canal ◽  
Head Impulse ◽  
Ocular Tilt Reaction ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Visual Vertical

Objective:To determine the role of the medial longitudinal fasciculus (MLF) in conveying vestibular signals.Methods:In 10 patients with isolated acute unilateral internuclear ophthalmoplegia (INO) due to an acute stroke, we performed comprehensive vestibular evaluation using video-oculography, head impulse tests with a magnetic search coil technique, bithermal caloric tests, tests for the ocular tilt reaction, and measurements of subjective visual vertical and cervical and ocular vestibular evoked myogenic potentials (VEMPs).Results:The head impulse gain of the vestibulo-ocular reflex (VOR) was decreased invariably for the contralesional posterior canal (PC) (n = 9; 90%) and usually for the ipsilesional horizontal canal (n = 5; 50%). At least one component of contraversive ocular tilt reaction (n = 9) or contraversive tilt of the subjective visual vertical (n = 7) were common along with ipsitorsional nystagmus (n = 5). Cervical or ocular VEMPs were abnormal in 5 patients.Conclusions:The MLF serves as the main passage for the high-acceleration VOR from the contralateral PC. The associations and dissociations of the vestibular dysfunction in our patients indicate variable combinations of damage to the vestibular fibers ascending or descending in the MLF even in strokes causing isolated unilateral INO.

scholarly journals Eight and a Half Syndrome: A Rare Case of Pontine Infarction

2021 ◽  
Vol 13 (2) ◽  
pp. 230-233
Author(s):  
Akkayasamy Kowsalya
Keyword(s):  
Facial Nerve ◽  
Nerve Palsy ◽  
Facial Nerve Palsy ◽  
Abducens Nerve ◽  
Medial Longitudinal Fasciculus ◽  
Internuclear Ophthalmoplegia ◽  
Pontine Infarction ◽  
Nerve Nucleus ◽  
The Right ◽  
Gaze Palsy

Introduction: This case report describes “one-and-a-half” syndrome with supranuclear facial palsy. Case: 39 years old male hypertensive patient presented with right facial nerve palsy, internuclear ophthalmoplegia and conjugate gaze palsy. Neuroimaging showed acute posterior pontine infarct at medial longitudinal fasciculus, paramedian pontine  reticular formation, abducens nerve nucleus and seventh nerve fascicular zone. Observation: “One-and-a-half”syndrome is characterized by a lateral gaze palsy in one direction and internuclear ophthalmoplegia in the other. Our patient had Right sided one and a half syndrome along with the right facial nerve palsy.   Conclusion: Eight and a half syndrome is a rare manifestation of pontine infarction.

scholarly journals A review on screening tests for vestibular disorders

2019 ◽  
Vol 122 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Helen S. Cohen
Keyword(s):  
Vestibular System ◽  
Epidemiological Studies ◽  
Screening Tests ◽  
Clinical Test ◽  
Clinical Use ◽  
Ocular Reflex ◽  
System A ◽  
Screening Battery ◽  
Vestibulo Ocular Reflex ◽  
Romberg Test

Although many studies have reported on tests of the vestibular system a valid and reliable, evidence-based screening battery for easy clinical use remains elusive. Many screening tests attempt to assess the vestibulo-ocular reflex. Therefore, head shaking, the Dix-Hallpike maneuver, the supine roll test, and head impulse tests are discussed. Other tests address the spatial orientation functions of the vestibular system, such as the Bucket Test and the Fukuda Stepping test. Still, other tests are based on the known correlates with balance skills, both static and dynamic, such as tandem walking and the modern variation of the Romberg test, the modified Clinical Test of Sensory Interaction and Balance. This review provides a critical overview of the literature on some of these tests and their value for clinical use and in epidemiological studies.

scholarly journals Age-Related Changes in Human Vestibulo-Ocular Reflexes: Sinusoidal Rotation and Caloric Tests

1990 ◽  
Vol 1 (1) ◽  
pp. 49-59 ◽  
Author(s):  
R.J. Peterka ◽  
F.O. Black ◽  
M.B. Schoenhoff
Keyword(s):  
Human Subjects ◽  
Normal Population ◽  
Poor Correlation ◽  
Caloric Test ◽  
Compensatory Response ◽  
Ocular Reflex ◽  
Age Related ◽  
Test Parameters ◽  
Vestibulo Ocular Reflex ◽  
Effects Of Aging

The dynamic response properties of horizontal vestibulo-ocular reflex (VOR) were characterized in 216 human subjects ranging in age from 7 to 81 y. The effects of aging on VOR dynamics and parameter distributions that describe VOR responses to caloric and to sinusoidal rotational stimuli were determined in a putatively normal population. Caloric test parameters showed no consistent trend with age. Rotation test parameters showed declining response amplitude and slightly less compensatory response phase with increasing age. The magnitudes of these changes were not large relative to the variability within the population. The age-related trends in VOR were not consistent with the anatomic changes in the periphery reported by others that showed an increasing rate of peripheral hair cell and nerve fiber loss in subjects over 55 y. The poor correlation between physiological and anatomical data suggest that adaptive mechanisms in the central nervous system are important in maintaining the VOR.

S223 – Effect of Myopia on the Caloric Test

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P150-P150
Author(s):  
Alok Thakar
Keyword(s):  
Retinal Image ◽  
Contact Lenses ◽  
Significant Proportion ◽  
Control Group ◽  
Caloric Test ◽  
Case Group ◽  
Direct Evaluation ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
The Impact

Objectives To assess the impact of corrected myopia on the caloric test. Correction of myopia with spectacles or contact lenses results in alteration of the size of the retinal image. Previous laboratory experiments have demonstrated that gross changes in the size of the retinal image can result in recalibration or suppression of the vestibulo-ocular reflex (VOR). Methods Case-control study. 17 evaluable healthy volunteers with myopia corrected either by spectacles or contact lenses (case group) compared to 17 volunteers with no refractive error (control group). Complete Electro-Nystagmography inclusive of bithermal caloric testing undertaken for cases and controls. Assessment of hypoactive caloric responses based on normative laboratory values. Results 7 of 17 cases and 1 of 17 controls demonstrated hypoactive caloric responses. In the spectacle users group, 6 of 11 (55%) had hypoactive responses. Spectacle users were significantly more likely than emmetropic controls to have hypoactive caloric responses (p<0.01; relative risk 9.3 {95 % Confidence Interval 1.3 to 66.9}). Conclusions 1) A significant proportion of myopes using spectacles have suppression of the vestibulo-ocular reflex as demonstrated by the caloric test. This has implications for the interpretation of ENG results, and also as a cause of vestibular impairment. 2) Further studies in myopes are warranted for precise and direct evaluation of the VOR by rotation or impulse testing.

Does spectacle use lead to vestibular suppression?

2016 ◽  
Vol 130 (11) ◽  
pp. 1033-1038
Author(s):  
A Thakar
Keyword(s):  
Retinal Image ◽  
Contact Lenses ◽  
Preliminary Investigation ◽  
Significant Proportion ◽  
Head Impulse Test ◽  
Caloric Test ◽  
Image Size ◽  
Cross Sectional ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

AbstractBackground:Laboratory experiments indicate that changes in retinal image size result in adaptive recalibration or suppression of the vestibulo-ocular reflex. Myopia correction with spectacles or contact lenses also leads to retinal image size changes, and may bring about similar vestibulo-ocular reflex alterations.Methods:A hypothesis-generating preliminary investigation was conducted. In this cross-sectional study, findings of electronystagmography including bithermal caloric testing were compared between 17 volunteer myopes using spectacles or contact lenses and 17 volunteer emmetropes (with no refractive error).Results:Bilateral hypoactive caloric responses were demonstrated in 6 of 11 spectacle users, in 1 of 6 contact lens users and in 1 of 17 emmetropes. Hypoactive caloric responses were significantly more likely in spectacle users than in emmetropes (p < 0.01; relative risk = 9.3).Conclusion:A significant proportion of myopes using spectacles have vestibulo-ocular reflex suppression, as demonstrated by the caloric test. This has implications for the interpretation of electronystagmography and videonystagmography results, and highlights spectacle use as a possible cause of vestibular impairment. Further corroboration of these findings is warranted, with more precise and direct vestibulo-ocular reflex tests such as rotational tests and the head impulse test.

Vestibulo-ocular reflex deficits with medial longitudinal fasciculus lesions

2017 ◽  
Vol 264 (10) ◽  
pp. 2119-2129 ◽  
Author(s):  
Swee T. Aw ◽  
Luke Chen ◽  
Michael J. Todd ◽  
Michael H. Barnett ◽  
G. Michael Halmagyi
Keyword(s):  
Medial Longitudinal Fasciculus ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Vestibulo-ocular reflex pathways in internuclear ophthalmoplegia

1999 ◽  
Vol 45 (4) ◽  
pp. 529-533 ◽  
Author(s):  
Phillip D. Cremer ◽  
Americo A. Migliaccio ◽  
G. Michael Halmagyi ◽  
Ian S. Curthoys
Keyword(s):  
Internuclear Ophthalmoplegia ◽  
Ocular Reflex ◽  
Reflex Pathways ◽  
Vestibulo Ocular Reflex
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