Abduction paresis with rostral pontine and/or mesencephalic lesions: Pseudoabducens palsy and its relation to the so-called posterior internuclear ophthalmoplegia of Lutz

Abstract

Background: The existence of a prenuclear abduction paresis is still debated.

Cranial Nerves III, IV, and VI

“…64 MRI and CT failed to identify these lesions in most cases, but the majority were thought to represent ischemic infarction and a few were thought to be multiple sclerosis plaques. 64 MRI and CT failed to identify these lesions in most cases, but the majority were thought to represent ischemic infarction and a few were thought to be multiple sclerosis plaques.…”

A rare cause for visual symptoms in multiple sclerosis: posterior internuclear ophthalmoplegia of Lutz, a historical misnomer

“…This condition is first described by the German Ophthalmologist Anton Lutz in 1923 [2], and only a few cases of pINO in MS have ever been reported [3]. In contrast, a classical INO due to demyelination of the medial longitudinal fasciculus (MLF) can be detected by oculography in about a quarter of MS patients [4].…”

“…Three plausible mechanisms are described in literature. First, a failure to relax the medial rectus muscle due to a midbrain lesion [3,7]. Second, an interruption of the projection of internuclear neurons to the contralateral abducens nucleus via the MLF due to a midbrain lesion [8,9].…”

“…Clinically, a pINO of Lutz can be distinguished from a 6th nerve palsy, by (1) alignment of the eyes and no diplopia in primary position, (2) unrestricted abduction with pursuit eye movements, (3) preserved abduction (saccades) with caloric testing and the vestibulo-ocular reflex, and (4) possible adduction nystagmus of the contralateral eye on lateral gaze [3]. The findings in our case suggest that infrared oculography has an added value as a clinical tool for detailed investigation of this yet enigmatic sign and for unexplained visual complaints in multiple sclerosis.…”

Operative management of brainstem cavernous malformations

“…This tract is involved in the masseter reflex arc; damage to it does not necessarily lead to loss of facial sensation or motor function. 65 Electrophysiological recording of the oculomotor system can be performed to map these important structures prior to resection of the CM. 55 However, there is less certainty regarding the predictive ability of mechanically evoked electromyographic activity in the extraocular muscles to signify injury to the brainstem oculomotor system.…”