2024 American Academy of Neurology Abstract Website

Objective:

To highlight the localizing value of peripheral and central utriculo-ocular pathways by walking through four sequenced, illustrative clinical cases (with fundus images and/or clinical videos). Each case serves as a “waystation” along the same pathway originating in the right ear and ending in the left midbrain, to demonstrate how different anatomic lesions (in some cases, across the midline) can yield similar clinical findings.

Background:

The utriculo-ocular pathway has specific neuro-anatomic localization, from the utricle in the labyrinth to the ipsilateral vestibular nerve and nucleus, crossing at the ponto-medullary junction, ascending in the contralateral medial longitudinal fasciculus and reaching the interstitial nucleus of Cajal (INC). Dysfunction anywhere along this pathway can cause the pathologic ocular tilt reaction (triad of ocular counter-roll [OCR], head tilt, and skew deviation).

Design/Methods:

We outline four clinical cases, all involving the same utriculo-ocular pathway beginning in the right labyrinth and ending in the left midbrain. Cases originate from https://novel.utah.edu/Gold/.

Results:

(1) A case of acute right-sided vestibular neuritis causing OCR towards the lesioned right side (top pole of each eye rotated towards the ipsilateral right ear).

(2) A case of right lateral medullary syndrome causing OCR towards the lesioned right side.

(3) A case of an ischemic stroke involving the left INC causing OCR away from the lesioned left side (top pole of each eye rotated towards the contralateral right ear).

(4) A case of presumed excitation/irritation of the INC causing paroxysmal OCR towards the ipsilateral left ear. The patient had had a hypertensive hemorrhage in that area 2 years prior; MRI later showed hemosiderin deposition in the rostral left midbrain.

Conclusions:

Knowledge of the utriculo-ocular pathway has helpful bedside localizing value in lesions of the vestibular apparatus and brainstem. By following a series of real cases, arranged anatomically, learners and clinicians can better understand this pathway and its anatomy.