Mastication-induced vertigo and nystagmus.

Area of Science:

• Neuroscience
• Otolaryngology
• Neurology

Background:

• Trigeminovestibular connections are established in animals, but mastication-induced dizziness in humans is often attributed to vascular steal.
• This study investigates mastication's effect on vertigo and nystagmus in human patients with various vestibulopathies.

Observation:

• Two index patients with unilateral peripheral vestibulopathy developed mastication-induced vertigo and nystagmus after initial recovery.
• Mastication did not induce nystagmus in healthy controls.
• Nystagmus was induced in 24% of patients without spontaneous nystagmus but with a history of vestibular syndrome.

Findings:

• Mastication modulated spontaneous nystagmus in 90% of patients with acute vestibulopathy, either increasing or decreasing its presence.
• Mastication-induced vertigo and nystagmus occurred in patients with both peripheral (vestibular neuritis, Meniere's disease) and central (Wallenberg syndrome, cerebellar/pontine infarction) vestibulopathies.
• Normal brain MRI and cerebral angiography in index patients ruled out vascular causes.

Implications:

• Mastication can induce significant vertigo and nystagmus in patients with a history of acute vestibulopathy.
• Findings support trigeminal modulation of the human vestibular system.
• The gradual onset and resolution suggest the velocity storage mechanism contributes to mastication-induced vertigo and nystagmus.