Search results
Results From The WOW.Com Content Network
Horizontal gaze palsies can be caused by a lesion affecting any structure in these pathways. Lesions to abducens nucleus or PPRF typically create an ipsilateral gaze palsy, while lesions to MLF typically cause Internuclear ophthalmoplegia , a type of horizontal gaze palsy in which the affected eye cannot adduct in conjugation with the ...
Destructive lesions of the PPRF cause ipsilateral horizontal conjugate gaze palsy and mostly impair ipsilateral horizontal saccades, however, other horizontal and vertical eye movements may also be affected as the PPRF contains multiple distinct populations of neurons important in saccade generation, as well as being traversed by nerve fibers ...
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.
Conjugate gaze palsy: Conjugate gaze palsies typically affect horizontal gaze, although some affect upward gaze. Few affect downward gaze. Few affect downward gaze. These effects can range in severity from a complete lack of voluntary eye movement to mild impairments in speed, accuracy or range of eye movement.
More formally, it is characterized by "a conjugate horizontal gaze palsy in one direction and an internuclear ophthalmoplegia in the other". [1] [2] Nystagmus is also present when the eye on the opposite side of the lesion is abducted. Convergence is classically spared as cranial nerve III (oculomotor nerve) and its nucleus is spared bilaterally.
The conjugate gaze is the motion of both eyes in the same direction at the same time, and conjugate gaze palsy refers to an impairment of this function. The conjugate gaze is controlled by four different mechanisms: [4] the saccadic system that allows for voluntary direction of the gaze; the pursuit system that allows the subject to follow a ...
The paramedian pontine reticular formation (PMPRF) is involved in coordinating horizontal conjugate eye movements and saccades. To do so, besides projecting to the ibsilateral abducens nucleus, the PMPRF projects fibers through the MLF to the contralateral oculomotor nucleus (specifically, those of its motor neurons that innervate the medial rectus muscle).
It has less commonly been associated with spasm of accommodation on attempted upward gaze, pseudoabducens palsy (also known as thalamic esotropia) or slower movements of the abducting eye than the adducting eye during horizontal saccades, see-saw nystagmus and associated ocular motility deficits including skew deviation, oculomotor nerve palsy ...