Clinical And MRI Findings Of Patients With InterNuclear Ophthalmoplegia
Ohbuchi T, Udaka T, Tokui N, Yamamoto H, Shiomori T, Fujimura T, Shimizu T, Suzuki H
Nippon Jibiinkoka Gakkai Kaiho 2006 Feb;109(2):96-102
University of Occupational and Environmental Health, School of Medicine, Department of Otorhinolaryngology, Kitakyushu, Fukuoka
InterNuclear Ophthalmoplegia (INO) is a distinctive ocular motor disorder resulting from dysfunction of the Medial Longitudinal Fasciculus, which lies in the Pontine Tegmentum.
We retrospectively analyzed clinical and Magnetic Resonance Imaging (MRI) findings for four consecutive patients with InterNuclear Ophthalmoplegia who were treated in our hospital.
The causes of the disease were Cerebral Infarction in three cases and Multiple Sclerosis in one case. Vertigo and Facial Nerve Palsy were associated in three cases and one case, respectively.
MRI studies visualized an Ischemic lesion in the responsible portion of the BrainStem in one patient but failed to reveal responsible lesions in the other three patients.
All the patients completely recovered in 1 to 22 days, with an average recovery period of 9.3 days. The etiology, diagnosis and management of INO were bibliographically reviewed.
The Control Of Gaze (3). Neurological Defects
Med Sci (Paris) 2004 Mar;20(3):357-62
Inserm U.289 et Service de Neurologie 1, Hopital de la Salpetriere, 47, boulevard de l'Hopital, 75651 Paris Cedex 13, France
Eye movements serve vision, which has two different aims: changing images using Saccades, i.e. rapid eye movements, and stabilizing new images on the Retina using slow eye movements.
Eye movements are performed by Ocular Motor Nuclei in the BrainStem, on which SupraNuclear pathways - originating in the Cerebral Cortex, Cerebellum and Vestibular structures - converge.
It is useful for the Neurologist to know the clinical abnormalities of eye movements visible at the bedside since such signs are helpful for localization.
Eye movement paralysis may be Nuclear or Infranuclear (Nerves), involving all types of eye movements, i.e. Saccades as well as the Vestibulo-Ocular Reflex (VOR), or SupraNuclear, in which case the VOR is usually preserved.
Lateral eye movements are organized in the Pons, with paralysis of adduction (and preservation of Convergence) when the lesion affects the Medial Longitudinal Fasciculus (InterNuclear Ophthalmoplegia).
Paralysis of conjugate lateral eye movements when the lesion affects the Abducens Nucleus (VI) and the "One-And-A-Half" Syndrome when both these structures are involved.
Vertical eye movements are organized in the MidBrain, with Ipsilateral Oculomotor (III) paralysis and ContraLateral Paralysis of the Superior Rectus Muscle when the Third Nerve Nucleus is unilaterally damaged.
SupraNuclear Upward Gaze Paralysis when the Posterior Commissure is UniLaterally damaged and SupraNuclear Downward Gaze Paralysis (often coupled with Upward Gaze Paralysis) when the Mesencephalic Reticular Formations are BiLaterally damaged.
Numerous types of abnormal eye movements exist, of which Nystagmus is the most frequent and usually due to damage to peripheral or Central Vestibular Pathways.
Cerebral Hemispheric or Cerebellar damage results in subtle eye movement abnormalities at the bedside, in general only detected using eye movement recordings.
Because of the multiplicity of eye movement pathways at these levels and their reciprocal compensation in the case of a lesion. Lastly, eye movements can also help the NeuroScientist to understand the organization of the Brain.
They are a good model of Motricity allowing us, using eye movement recordings, to study the Afferent Pathways of the Cortical Areas that trigger them.
And, thus to analyze relatively complex NeuroPsychological processes such as Visuo-Spatial Integration, Spatial Memory, Motivation and the preparation of Motor Programs.
Near Reflex Substituting For Acquired Horizontal Gaze Palsy: A Case Report
Kohno T, Oohira A, Hori S
Jpn J Ophthalmol 2004 Nov-Dec;48(6):584-6
Tokyo Women's Medical University, Department of Ophthalmology, Tokyo, Japan
Some patients with Acquired Horizontal Gaze Palsy overcome the Adduction Palsy by utilizing convergence.
This substitution phenomenon is very rare. We report a patient with Horizontal Gaze Palsy who was able to use convergence to compensate for the lack of adduction in the left eye.
The patient was a 31-year-old woman with an ArterioVenous Malformation in the Fourth Ventricle.
She suffered Right Gaze Palsy and Right Abducens Palsy after tumor surgery and radiation therapy.
Three years after the Vascular accident, she was found to be able to adduct the left eye, in association with the adduction of the right eye.
At the same time, constriction of both pupils and globe retraction of the left eye were observed.
When she shifted the gaze direction of her left eye from left to right, an 11 and 8 diopter increase of Myopia in the right and left eyes, respectively, was confirmed by objective Refractometry.
The existence of convergence substituting for adduction in this patient with Horizontal Gaze Palsy was confirmed by refraction change in addition to Pupillary change.
MRI Characteristics Of The MLF In MS Patients With Chronic InterNuclear Ophthalmoparesis
Frohman EM, Zhang H, Kramer PD, Fleckenstein J, Hawker K, Racke MK, Frohman TC
Neurology 2001 Sep 11;57(5):762-8
University of Texas Southwestern Medical Center, Department of Neurology, Dallas 02115, USA
The authors imaged the Medial Longitudinal Fasciculus (MLF) in 58 patients with MS and chronic InterNuclear Ophthalmoparesis (INO) to determine which MRI technique best shows the characteristic lesion associated with this Ocular Motor Syndrome.
Using quantitative infrared Oculography, the authors determined the ratios of Abduction to Adduction for Velocity and Acceleration.
To confirm the presence of INO and to determine the severity of MLF dysfunction in 58 patients with MS and INO.
Conventional MRI techniques, including Proton Density Imaging (PDI), T2-weighted imaging, and Fluid-Attenuated Inversion Recovery (FLAIR) imaging, were used to ascertain which technique best shows MLF lesions within the BrainStem Tegmentum.
T1-weighted imaging was performed to determine the frequency of BrainStem Tegmentum HypoIntensities.
All patients studied had evidence of an MLF lesion HyperIntensity on PDI, whereas T2-weighted imaging and FLAIR imaging showed these lesions in 88% and 48% of patients, respectively.
With PDI, DorsoMedial Tegmentum lesions were seen in the Pons in 93% of patients and in the MidBrain of 66% of patients.
Lesions were observed at both locations in 59% of patients. One patient had an MLF lesion with a corresponding T1 HypoIntensity.
PDI best shows the MLF lesion in patients with MS and INO.
A Hypothetical Scheme For The BrainStem Control Of Vertical Gaze
Bhidayasiri R, Plant GT, Leigh RJ
Neurology 2000 May 23;54(10):1985-93
Case Western Reserve University, Department of Neurology, Department of Veterans Affairs Medical Center and University Hospitals, Cleveland, OH 44106-5040, USA
To develop a hypothetical scheme to account for clinical disorders of Vertical Gaze based on recent insights gained from experimental studies.
The authors critically reviewed reports of anatomy, physiology, and effects of pharmacologic inactivation of MidBrain Nuclei.
Vertical Saccades are generated by burst Neurons lying in the rostral interstitial Nucleus of the Medial Longitudinal Fasciculus (riMLF).
Each burst Neuron projects to MotoNeurons in a manner such that the eyes are tightly coordinated (yoked) during Vertical Saccades.
Saccadic innervation from right MLF is unilateral to depressor muscles but BiLateral to elevator muscles, with Axons crossing within the Oculomotor Nucleus.
Thus, right MLF lesions cause Conjugate Saccadic Palsies that are usually either complete or selectively downward. Each right MLF contains burst Neurons for both up and down Saccades, but only for Ipsilateral Torsional Saccades.
Therefore, unilateral right MLF lesions can be detected at the bedside if torsional quick phases are absent during IpsiDirectional head rotations in roll.
The Interstitial Nucleus of Cajal (INC) is important for holding the eye in Eccentric Gaze after a Vertical Saccade and coordinating eye-head movements in roll.
BiLateral INC lesions limit the range of Vertical Gaze. The Posterior Commissure (PC) is the route by which INC projects to Ocular MotoNeurons.
Inactivation of PC causes Vertical Gaze-Evoked Nystagmus, but destructive lesions cause a more profound defect of Vertical Gaze, probably due to involvement of the Nucleus of the PC.
Vestibular signals originating from each of the Vertical Labyrinthine Canals ascend to the MidBrain through several distinct pathways.
Normal Vestibular function is best tested by rotating the patient's head in the planes of these canals.
Predictions of a current scheme to account for Vertical Gaze Palsy can be tested at the bedside with systematic examination of each functional class of eye movements.