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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.
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 ...
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.
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 ...
Disorders of conjugate gaze typically consist of the inability to move one or both eyes in the desired direction, or the inability to prevent eyes from making vergence movements. Conjugate gaze palsy: Conjugate gaze palsies typically affect horizontal gaze, although some affect upward gaze. Few affect downward gaze.
The diagnostic criteria for Athabaskan brainstem dysgenesis syndrome include: [1] Verification of sensorineural deafness by brainstem auditory evoked responses. [1]Upon conjugate lateral gazing, there is horizontal gaze palsy; however, the medial gaze remains intact with convergence.
Brodmann area 8. The frontal eye fields (FEF) are a region located in the frontal cortex, more specifically in Brodmann area 8 or BA8, [1] of the primate brain.In humans, it can be more accurately said to lie in a region around the intersection of the middle frontal gyrus with the precentral gyrus, consisting of a frontal and parietal portion. [2]