Selective otolithic dysfunction in patients presenting with acute spontaneous vertigo: consideration based on MRI

Acute unilateral peripheral vestibulopathy or vestibular neuritis (AUPV/VN) manifests as acute onset vertigo, often accompanied by nausea, vomiting, and moderate gait instability. It is suspected when vestibular hypofunction is documented on video-head impulse (video-HITs) and caloric tests in the presence of contralesionally beating horizontal-torsional nystagmus. Herein, we report patients presenting with acute vestibular syndrome (AVS) showing selective otolithic dysfunction in the presence of normal caloric and video-HITs and abnormal enhancement of the peripheral vestibular structures on MRI.

We retrospectively reviewed the medical records of patients presenting with AVS between September 2019 and April 2024 at a tertiary referral hospital in South Korea. All patients underwent extensive neurotologic evaluation, including cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP, respectively), subjective visual vertical, video-oculography, video-HITs, caloric tests, and audiometry. Patients also underwent MRI according to a standard protocol for the inner ear and internal acoustic canal with an additional 3D-fluid attenuated inversion recovery sequence acquired 4 h after intravenous gadolinium injection.

We identified four patients with selective otolith dysfunction. Video-HITs and caloric test results were normal in all patients, except one with a canal paresis on the opposite side of otolithic dysfunction. Patients usually showed abnormal oVEMP (n = 3) and cVEMP (n = 2) or subjective visual vertical (n = 3). Gadolinium enhancements were found in the vestibule (n = 3), inferior (n = 2) or superior (n = 1) vestibular nerves on dedicated inner ear MRI.

Selective otolithic dysfunction can present with AVS, which can be easily overlooked. A thorough neurotologic evaluation and MRI dedicated to the inner ear can help detect selective otolithic dysfunction, expanding the clinical spectrum of AVS.