Conjugate gaze palsy

Last updated
Conjugate gaze palsy
Specialty Neurology

Conjugate gaze palsies are neurological disorders affecting the ability to move both eyes in the same direction. These palsies can affect gaze in a horizontal, upward, or downward direction. [1] These entities overlap with ophthalmoparesis and ophthalmoplegia.

Contents

Signs and symptoms

Symptoms of conjugate gaze palsies include the impairment of gaze in various directions and different types of movement, depending on the type of gaze palsy. Signs of a person with a gaze palsy may be frequent movement of the head instead of the eyes. [2] For example, a person with a horizontal saccadic (saccade) palsy may jerk their head around while watching a movie or high action event instead of keeping their head steady and moving their eyes, which usually goes unnoticed. Someone with a nonselective horizontal gaze palsy may slowly rotate their head back and forth while reading a book instead of slowly scanning their eyes across the page.[ citation needed ]

Cause

A lesion, which is an abnormality in tissue due to injury or disease, can disrupt the transmission of signals from the brain to the eye. Almost all conjugate gaze palsies originate from a lesion somewhere in the brain stem, usually the midbrain, or pons. These lesions can be caused by stroke, or conditions such as Koerber-Salus-Elschnig syndrome, Progressive supranuclear palsy, Olivopontocerebellar syndrome, Niemann-Pick Disease, Type C, or envenomation such as from a scorpion sting. [3]

Mechanism

The location of the lesion determines the type of palsy. Nonselective horizontal gaze palsies are caused by lesions in the Abducens nucleus. This is where the cranial nerve VI leaves on its way to the Lateral rectus muscle, which controls eye movement horizontally away from the midline of the body. The cranial nerve VI also has interneurons connecting to the medial rectus, which controls horizontal eye movement towards from the midline of the body. [4] Since the lateral rectus controls movement away from the center of the body, a lesion in the abducens nucleus disrupts the pathways controlling outward movements, not allowing the right eye to move right and the left eye to move left. Nerve VI has the longest subarachnoid distance to its target tissue, making it susceptible to lesions. [5] Lesions anywhere in the abducens nucleus, cranial nerve VI neurons, or interneurons can affect eye movement towards the side of the lesion. Lesions on both sides of the abducens nucleus can cause a total loss of horizontal eye movement. [6]

One other type of gaze palsy is a horizontal saccadic palsy. Saccades are very quick intermittent eye movements. [7] The paramedian pontine reticular formation(PPRF), also in the pons is responsible for saccadic movement, relaying signals to the abducens nucleus. [8] Lesions in the PPRF cause what would be saccadic horizontal eye movements to be much slower or in the case of very severe lesions, nonexistent. [6] Horizontal gaze palsies are known to be linked to Progressive Scoliosis. [9] This occurs because pathways controlling saccadic movements are disrupted by the lesion and only slow movements controlled by a different motor pathway are unaffected.

Lesions in the midbrain can interfere with efferent motor signals before they arrive at the pons. This can also cause slowed horizontal saccadic movements and failure for the eye to reach its target location during saccades. This damage normally happens in the oculomotor nucleus of the midbrain [10] As in horizontal saccadic palsy, the saccades are stopped or slowed from the disrupted pathway, only in this case the signal is disrupted before it reaches the PPRF.

One-and-a-half syndrome is associated with damage to the paramedian pontine reticular formation and the medial longitudinal fasciculus. [11] These combined damages cause both a complete gaze impairment on the ipsilateral side and a "half" gaze impairment on the contralateral side. [6] As seen in horizontal saccadic palsy, the impairment of the contralateral side gaze is caused by the disrupted pathways coming from the PPRF, while the "half" impairment is from the signal passing through the medial longitudinal fascicles not being able to reach its target. One-and-a-Half syndrome is normally associated with horizontal gaze.

Although more rare than horizontal, one-and-a-half syndrome from damage to the paramedian pontine reticular formation and the medial longitudinal fasciculus can be shown to affect vertical gaze. This can cause impairment of vertical gaze, allowing only one eye to move vertically. [6]

Diagnosis

A patient may be diagnosed with a conjugate gaze palsy by a physician performing a number of tests to examine the patient's eye movement abilities. In most cases, the gaze palsy can simply be seen by inability to move both eyes in one direction. However, sometimes a patient exhibits an abduction nystagmus in both eyes, indicating evidence of a conjugate gaze palsy. [12] A nystagmus is a back and forth "jerk" of the eye when attempting to hold a gaze in one direction. [13]

Classification

Conjugate gaze palsies can be classified into palsies affecting horizontal gaze and vertical gaze.[ citation needed ]

Horizontal gaze palsies

Horizontal gaze palsies affect gaze of both eyes either toward or away from the midline of the body. Horizontal gaze palsies are generally caused by a lesion in the brain stem and connecting nerves, normally in the pons. [6]

Progressive scoliosis

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a very rare form of conjugate gaze palsy, appearing only in a few dozen families worldwide. HGPPS prevents horizontal movement of both eyes, causing people with this condition to have to move their head to see moving objects. In addition to the eye movement impairment, HGPPS is coupled with progressive scoliosis, although eye symptoms usually appear before scoliosis. HGPPS is caused by a mutation in the ROBO3 gene, which is important in cross-over of motor and sensory signals, preventing horizontal eye movement. In addition to the mutation, lesions in the midbrain and pons are common. This can also include a complete absence of a formation in the pons, the facial colliculus, which is responsible for some facial movements. [14] The cause of progressive scoliosis in HGPPS and why HGPPS does not affect vertical gaze is unclear. Progressive scoliosis is normally treated with surgery. [2]

Vertical gaze palsies

Vertical gaze palsies affect movement of one or both eyes either in upward direction, up and down direction, or more rarely only downward direction. Very rarely only movement of one eye in one direction is affected. Vertical gaze palsies are often caused by lesions to the midbrain due to a stroke or a tumor. In the case that only downward gaze is affected, the cause is normally progressive supranuclear palsy. [15]

Treatment

There is no treatment of conjugate gaze palsy itself, so the disease or condition causing the gaze palsy must be treated, likely by surgery. [1] As stated in the causes section, the gaze palsy may be due to a lesion caused by stroke or a condition. Some of the conditions such as Progressive supra nuclear palsy are not curable, [16] and treatment only includes therapy to regain some tasks, not including gaze control. Other conditions such as Niemann-Pick disease type C have limited drug therapeutic options. [17] Stroke victims with conjugate gaze palsies may be treated with intravenous therapy if the patent presents early enough, or with a surgical procedure for other cases. [18]

Prognosis

The prognosis of a lesion in the visual neural pathways that causes a conjugate gaze palsy varies greatly. Depending on the nature of the lesion, recovery may happen rapidly or recovery may never progress. For example, optic neuritis, which is caused by inflammation, may heal in just weeks, while patients with an ischemic optic neuropathy may never recover. [19] [20]

Related Research Articles

<span class="mw-page-title-main">Cranial nerves</span> Nerves that emerge directly from the brain and the brainstem

Cranial nerves are the nerves that emerge directly from the brain, of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck, including the special senses of vision, taste, smell, and hearing.

<span class="mw-page-title-main">Saccade</span> Eye movement

A saccade is a quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction. In contrast, in smooth-pursuit movements, the eyes move smoothly instead of in jumps. The phenomenon can be associated with a shift in frequency of an emitted signal or a movement of a body part or device. Controlled cortically by the frontal eye fields (FEF), or subcortically by the superior colliculus, saccades serve as a mechanism for fixation, rapid eye movement, and the fast phase of optokinetic nystagmus. The word appears to have been coined in the 1880s by French ophthalmologist Émile Javal, who used a mirror on one side of a page to observe eye movement in silent reading, and found that it involves a succession of discontinuous individual movements.

<span class="mw-page-title-main">Abducens nerve</span> Cranial nerve VI, for eye movements

The abducens nerve or abducent nerve, also known as the sixth cranial nerve, cranial nerve VI, or simply CN VI, is a cranial nerve in humans and various other animals that controls the movement of the lateral rectus muscle, one of the extraocular muscles responsible for outward gaze. It is a somatic efferent nerve.

<span class="mw-page-title-main">Trochlear nerve</span> Cranial nerve IV, for eye movements

The trochlear nerve, also known as the fourth cranial nerve, cranial nerve IV, or CN IV, is a cranial nerve that innervates a single muscle - the superior oblique muscle of the eye. Unlike most other cranial nerves, the trochlear nerve is exclusively a motor nerve.

<span class="mw-page-title-main">Vestibulo–ocular reflex</span> Reflex where rotation of the head causes eye movement to stabilize vision

The vestibulo-ocular reflex (VOR) is a reflex acting to stabilize gaze during head movement, with eye movement due to activation of the vestibular system. The reflex acts to stabilize images on the retinas of the eye during head movement. Gaze is held steadily on a location by producing eye movements in the direction opposite that of head movement. For example, when the head moves to the right, the eyes move to the left, meaning the image a person sees stays the same even though the head has turned. Since slight head movement is present all the time, VOR is necessary for stabilizing vision: people with an impaired reflex find it difficult to read using print, because the eyes do not stabilise during small head tremors, and also because damage to reflex can cause nystagmus.

<span class="mw-page-title-main">Medial longitudinal fasciculus</span> Nerve tracts in the brainstem

The medial longitudinal fasciculus (MLF) is an area of crossed over tracts, on each side of the brainstem. These bundles of axons are situated near the midline of the brainstem. They are made up of both ascending and descending fibers that arise from a number of sources and terminate in different areas, including the superior colliculus, the vestibular nuclei, and the cerebellum. It contains the interstitial nucleus of Cajal, responsible for oculomotor control, head posture, and vertical eye movement.

<span class="mw-page-title-main">Eye movement</span> Movement of the eyes

Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms to fixate, inspect and track visual objects of interests. A special type of eye movement, rapid eye movement, occurs during REM sleep.

<span class="mw-page-title-main">Lateral rectus muscle</span> Muscle on lateral side of the eye

The lateral rectus muscle is a muscle on the lateral side of the eye in the orbit. It is one of six extraocular muscles that control the movements of the eye. The lateral rectus muscle is responsible for lateral movement of the eyeball, specifically abduction. Abduction describes the movement of the eye away from the midline, allowing the eyeball to move horizontally in the lateral direction, bringing the pupil away from the midline of the body.

<span class="mw-page-title-main">Extraocular muscles</span> Seven extrinsic muscles of the human eye

The extraocular muscles, or extrinsic ocular muscles, are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the other muscle, the levator palpebrae superioris, controls eyelid elevation. The actions of the six muscles responsible for eye movement depend on the position of the eye at the time of muscle contraction.

<span class="mw-page-title-main">Abducens nucleus</span>

The abducens nucleus is the originating nucleus from which the abducens nerve (VI) emerges—a cranial nerve nucleus. This nucleus is located beneath the fourth ventricle in the caudal portion of the pons near the midline, medial to the sulcus limitans.

<span class="mw-page-title-main">Internuclear ophthalmoplegia</span> Medical condition

Internuclear ophthalmoplegia (INO) is a disorder of conjugate lateral gaze in which the affected eye shows impairment of adduction. When an attempt is made to gaze contralaterally, the affected eye adducts minimally, if at all. The contralateral eye abducts, however with nystagmus. Additionally, the divergence of the eyes leads to horizontal diplopia. That is if the right eye is affected the patient will "see double" when looking to the left, seeing two images side-by-side. Convergence is generally preserved.

<span class="mw-page-title-main">Parinaud's syndrome</span> Inability to move the eyes up and down

Parinaud's syndrome is a constellation of neurological signs indicating injury to the dorsal midbrain. More specifically, compression of the vertical gaze center at the rostral interstitial nucleus of medial longitudinal fasciculus (riMLF).

Opsoclonus refers to uncontrolled, irregular, and nonrhythmic eye movement. Opsoclonus consists of rapid, involuntary, multivectorial, unpredictable, conjugate fast eye movements without inter-saccadic intervals. It is also referred to as saccadomania or reflexive saccade. The movements of opsoclonus may have a very small amplitude, appearing as tiny deviations from primary position.

<span class="mw-page-title-main">Sixth nerve palsy</span> Medical condition

Sixth nerve palsy, or abducens nerve palsy, is a disorder associated with dysfunction of cranial nerve VI, which is responsible for causing contraction of the lateral rectus muscle to abduct the eye. The inability of an eye to turn outward, results in a convergent strabismus or esotropia of which the primary symptom is diplopia in which the two images appear side-by-side. Thus, the diplopia is horizontal and worse in the distance. Diplopia is also increased on looking to the affected side and is partly caused by overaction of the medial rectus on the unaffected side as it tries to provide the extra innervation to the affected lateral rectus. These two muscles are synergists or "yoke muscles" as both attempt to move the eye over to the left or right. The condition is commonly unilateral but can also occur bilaterally.

<span class="mw-page-title-main">One and a half syndrome</span> Medical condition

The one and a half syndrome is a rare weakness in eye movement affecting both eyes, in which one cannot move laterally at all, and the other can move only in outward direction. More formally, it is characterized by "a conjugate horizontal gaze palsy in one direction and an internuclear ophthalmoplegia in the other". Nystagmus is also present when the eye on the opposite side of the lesion is abducted. Convergence is classically spared as cranial nerve III and its nucleus is spared bilaterally.

<span class="mw-page-title-main">Paramedian pontine reticular formation</span>

The paramedian pontine reticular formation, also known as PPRF or paraabducens nucleus, is part of the pontine reticular formation, a brain region without clearly defined borders in the center of the pons. It is involved in the coordination of eye movements, particularly horizontal gaze and saccades.

A horizontal gaze palsy is a subtype of gaze palsy in which conjugate, horizontal eye movements are limited by neurologic deficits. Horizontal gaze palsies typically result from an ipsilateral pontine lesion or a contralateral frontal lobe lesion.

The term gaze is frequently used in physiology to describe coordinated motion of the eyes and neck. The lateral gaze is controlled by the paramedian pontine reticular formation (PPRF). The vertical gaze is controlled by the rostral interstitial nucleus of medial longitudinal fasciculus and the interstitial nucleus of Cajal.

Conjugate eye movement refers to motor coordination of the eyes that allows for bilateral fixation on a single object. A conjugate eye movement is a movement of both eyes in the same direction to maintain binocular gaze. This is in contrast to vergence eye movement, where binocular gaze is maintained by moving eyes in opposite directions, such as going “cross eyed” to view an object moving towards the face. Conjugate eye movements can be in any direction, and can accompany both saccadic eye movements and smooth pursuit eye movements.

<span class="mw-page-title-main">Corticomesencephalic tract</span>

In neuroanatomy, corticomesencephalic tract is a descending nerve tract that originates in the frontal eye field and terminate in the midbrain. Its fibers mediate conjugate eye movement.

References

  1. 1 2 "Conjugate Gaze Palsies: Neuro-ophthalmologic and Cranial Nerve Disorders: Merck Manual Professional". Merckmanuals.com. Retrieved 2013-07-07.
  2. 1 2 "Horizontal Gaze Palsy with Progressive Scoliosis. (2012).Gentics Home Reference". Ghr.nlm.nih.gov. 2013-07-01. Retrieved 2013-07-07.
  3. ↑ "Conjugate gaze palsy". RightDiagnosis.com. 2013-05-07. Retrieved 2013-07-07.
  4. ↑ "Eye Theory". Cim.ucdavis.edu. Archived from the original on 2011-07-26. Retrieved 2013-07-07.
  5. ↑ Abducens Nerve Palsy at eMedicine
  6. 1 2 3 4 5 "Barton, J., & Goodwin, J. (2001). Horizontal Gaze Palsy". Medlink.com. Archived from the original on 2008-03-24. Retrieved 2013-07-07.
  7. ↑ "Saccades - definition of Saccades in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia". Medical-dictionary.thefreedictionary.com. Retrieved 2013-07-07.
  8. ↑ "University of Western Ontario Department of Physiology. (1996). Basic Principles of Generating Horizontal Saccades". Schorlab.berkeley.edu. 1996-10-04. Retrieved 2013-07-07.
  9. ↑ Jain, Nitin R; Jethani, Jitendra; Narendran, Kalpana; Kanth, L (2011). "Synergistic convergence and split pons in horizontal gaze palsy and progressive scoliosis in two sisters". Indian Journal of Ophthalmology. 59 (2): 162–5. doi: 10.4103/0301-4738.77012 . PMC   3116551 . PMID   21350292.
  10. ↑ "The Canadian eTextbook of eye movements". Neuroophthalmology.ca. Archived from the original on 2014-03-08. Retrieved 2013-07-07.
  11. ↑ Terao, S (2000). "Coexisting vertical and horizontal one and a half syndromes". Journal of Neurology, Neurosurgery & Psychiatry. 69 (3): 401–2. doi:10.1136/jnnp.69.3.401. PMC   1737104 . PMID   10991648.
  12. ↑ Zee, DS (August 1992). "Internuclear ophthalmoplegia: pathophysiology and diagnosis". Baillière's Clinical Neurology. 1 (2): 455–70. PMID   1344079. NAID   10016339375.
  13. ↑ Hertle, Richard W. (September 2008). "Nystagmus in Infancy and Childhood". Seminars in Ophthalmology. 23 (5–6): 307–317. doi:10.1080/08820530802505955. PMID   19085433. S2CID   27757018.
  14. ↑ Bomfim, Rodrigo C.; Távora, Daniel G. F.; Nakayama, Mauro; Gama, Rômulo L. (February 2009). "Horizontal gaze palsy with progressive scoliosis: CT and MR findings". Pediatric Radiology. 39 (2): 184–187. doi:10.1007/s00247-008-1058-8. PMID   19020872. S2CID   2344092.
  15. ↑ "Conjugate Gaze Palsies: Cranial Nerve Disorders: Merck Manual Home Edition". Merckmanuals.com. Retrieved 2013-07-07.
  16. ↑ MedlinePlus Encyclopedia : Progressive supranuclear palsy
  17. ↑ Davidson, Cristin D.; Ali, Nafeeza F.; Micsenyi, Matthew C.; Stephney, Gloria; Renault, Sophie; Dobrenis, Kostantin; Ory, Daniel S.; Vanier, Marie T.; Walkley, Steven U. (11 September 2009). "Chronic Cyclodextrin Treatment of Murine Niemann-Pick C Disease Ameliorates Neuronal Cholesterol and Glycosphingolipid Storage and Disease Progression". PLOS ONE. 4 (9): e6951. Bibcode:2009PLoSO...4.6951D. doi: 10.1371/journal.pone.0006951 . PMC   2736622 . PMID   19750228.
  18. ↑ Goldstein, Larry B.; Simel, DL (18 May 2005). "Is This Patient Having a Stroke?". JAMA. 293 (19): 2391–2702. doi:10.1001/jama.293.19.2391. PMID   15900010.
  19. ↑ Jacobs, D. A.; Galetta, S. L. (1 January 2007). "Neuro-Ophthalmology for Neuroradiologists". American Journal of Neuroradiology. 28 (1): 3–8. PMC   8134093 . PMID   17213413.
  20. ↑ National Stroke Association. Stroke Treatment.[ full citation needed ]
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.