Selective otolith dysfunctions objectively verified.

Area of Science:

• Neuroscience
• Otolaryngology
• Vestibular System Research

Background:

• Acute vertigo and spontaneous nystagmus are typically attributed to unilateral horizontal semicircular canal dysfunction.
• This presumption guides initial diagnostic and treatment strategies for vestibular disorders.

Observation:

• The study observed three patients presenting with acute vestibular syndrome, characterized by vertigo and vigorous horizontal spontaneous nystagmus.
• Standard clinical interpretations suggested reduced horizontal canal function.

Findings:

• Comprehensive vestibular testing, including video head impulse testing (vHIT) and vestibular evoked myogenic potentials (VEMPs), was performed.
• Results indicated normal semicircular canal function in all patients.
• However, testing revealed significant unilateral otolithic deficits, suggesting these were the primary cause of the acute syndrome.

Implications:

• The findings challenge the conventional assumption linking horizontal nystagmus solely to semicircular canal deficits.
• This highlights the importance of evaluating otolith organ function in patients with acute vestibular symptoms.
• Accurate diagnosis of vestibular disorders may require a broader assessment beyond traditional canal-focused testing.