Gaze palsy is a term used to indicate a symmetric limitation of the movements of both eyes in the same direction (ie, a conjugate ophthalmoplegia). With a cerebral lesion (supranuclear), the term gaze preference denotes an acute inability to produce gaze contralateral to the side of the lesion and is accompanied by a tendency for tonic deviation of the eyes toward the side of the lesion. In such cases, the doll’s head maneuver generates a full range of horizontal eye movements because the infranuclear pathways are intact. Stroke is the most common etiology for this type of cerebral injury. The eye movement dysfunction is generally temporary, lasting only days or weeks. Presumably, alternative cerebral–bulbar pathways (perhaps from the parietal lobe) become increasingly capable of generating the saccades.
In contrast, brainstem lesions that produce a horizontal gaze palsy disrupt eye movements toward the side of the lesion (opposite to the pattern seen with lesions of the FEF) (Fig 7-4). With pontine lesions (nuclear and infranuclear), the final common site for supranuclear inputs (from volitional, reflex, and vestibular centers) is damaged, and thus the doll’s head maneuver is ineffective in driving the paretic eyes. Bilateral pontine injury can abolish all horizontal eye movements. This devastating injury still allows vertical eye movements, which often occur spontaneously (ie, ocular bobbing; see Chapter 9).
Congenital horizontal gaze palsy can occur as part of the Möbius syndrome, in which aplasia of the sixth nerve nuclei is accompanied by bilateral facial paresis. A gaze palsy rather than just an ipsilateral limitation in abduction occurs because the sixth nerve nucleus also contains internuclear neurons destined for the contralateral oculomotor nucleus (CN III) via the MLF.
Vertical gaze palsies can manifest as selective limitation of upgaze or downgaze. In either case, the lesion is usually in the midbrain. Limitation of conjugate upgaze occurs with damage to the pretectum, an isthmus between the superior colliculi and the thalamus. Supranuclear fibers decussate through the pretectum as they pass to the riMLF, the midbrain structure that functions as the saccadic generator for vertical eye movements (and thus is the homologue for the paramedian pontine reticular formation for horizontal saccades). The dorsal midbrain syndrome (also known as the pretectal or Parinaud syndrome;Fig 7-5) includes
conjugate limitation of vertical gaze (usually upgaze)
co-contraction of extraocular muscles, which causes retraction and convergence of the globes (convergence retraction nystagmus)
mid-dilated pupils with light–near dissociation
retraction of the lids in primary position (Collier sign)
disruption of convergence (convergence spasm or convergence palsy)
increased square-wave jerks
This syndrome often includes only a subset of these signs, although the limitation of conjugate upgaze is the most common feature. Common etiologies of the dorsal midbrain syndrome include mass lesions (especially pineal-based tumors), hydrocephalus, multiple sclerosis, and stroke.
The pretectum is the terminal structure supplied by the arteries of Percheron (small penetrating arteries that arise from the area around the top of the basilar artery; see Chapter 1). Stenosis at the origin of these vessels, disease of the more proximal basilar artery, and entrapment of emboli can all compromise flow through these vessels. Emboli that lodge at the top of the basilar artery can produce efferent and afferent neuro-ophthalmic problems.
Deviation of the eyes may occur with seizures involving any cerebral lobe. Most notably, a lesion of the FEF that causes excess neural activity, like a focal seizure, will drive the eyes contralaterally during the period of the seizure. The head also may turn contralateral to the seizure focus during the ictus. In the post-ictal state, when there may be lingering hypoactivity of the FEF neurons, the eyes may deviate ipsilateral to the side of the lesion because of a relative increase in input from the unaffected FEF on the opposite side of the brain.
Transient and conjugate downward or upward ocular deviation may occur in healthy newborns. In these cases, vertical doll’s head maneuver can move the eyes out of their tonically held position. Tonic downgaze in premature newborns, however, can be associated with serious neurologic disease, especially when intraventricular hemorrhage expands the third ventricle and impacts on the pretectum. The tonic deviation of the eyes, combined with retraction of the eyelids, is known as the setting sun sign; it is primarily seen in children as part of dorsal midbrain syndrome (Parinaud syndrome). Conjugate paresis of upgaze is an associated finding, and in these cases, the doll’s head maneuver cannot induce upward movements of the eyes.
Oculogyric crisis is a tonic upward deviation, sometimes directed toward the right or left, that does not disrupt a patient’s ability to move the eyes within the involved area. Patients find it difficult to direct their eyes downward. This disorder primarily is seen as an idiosyncratic reaction to neuroleptic drugs, especially the higher-potency antipsychotic drugs like haloperidol and fluphenazine (Prolixin), which are strong dopaminergic-blocking agents. These drugs alter the supranuclear influences onto the ocular motoneurons and thus create a tonic deviation of the eyes. The crisis may persist for hours if not treated. In the early 1900s, patients with postencephalitis parkinsonism often developed oculogyric crisis, but this syndrome is no longer seen. Very occasionally, patients with Wilson disease may develop an oculogyric crisis. Anticholinergic drugs (such as prochlorperazine) promptly stop the eye deviation.
. Oculogyric crisis. In: Joseph AB, Young RR, eds. 2nd ed. Malden, MA: Blackwell Science; 1999:chap 14.
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