Vestibular Migraine
A common cause of episodic vertigo with VEMP abnormalities that are frequent but heterogeneous — supportive of, but never diagnostic for, the condition.
What is vestibular migraine?
Vestibular migraine causes episodic vertigo in patients with a migraine background. Diagnostic criteria require at least five episodes of moderate-to-severe vestibular symptoms, with current or past migraine, and at least half of the episodes accompanied by migrainous features (headache, photophobia, phonophobia, or aura).
VEMP signature
- Reduced amplitudes (cVEMP and/or oVEMP) — the most common abnormality.
- Increased IAR.
- oVEMP more often affected than cVEMP.
- Latencies tend to be preserved.
Reading the report
The clinical role of VEMP in vestibular migraine is to exclude structural mimics (especially SCD and schwannoma) rather than to confirm migraine itself. Most guidelines, including the AAN 2017, do not recommend VEMP as a routine diagnostic test in this condition.[1]
That said, abnormal VEMPs are common enough in vestibular migraine that they can be a supportive piece of the picture — particularly when bilateral subtle amplitude reduction matches an otherwise compelling clinical story.
Pathophysiology — why VEMPs might be abnormal
The exact mechanism is debated. Hypotheses include cortical-spreading-depression-like changes that propagate to vestibular nuclei, transient ischaemia of vestibular afferents, and a long-standing background of vestibular sensitisation. None has been confirmed; until it is, VEMP remains a supportive — not diagnostic — finding in this condition.[14]