Broadening vestibular migraine diagnostic criteria: A prospective cohort study on vestibular migraine subtypes.

BACKGROUND: Current Bárány Society criteria for vestibular migraine (VM) include only episodic symptoms. Anecdotal observations suggest that some patients have episodic forms and others have chronic forms of VM, with interplay and evolution of both subtypes over time. OBJECTIVE: To better understand VM subtypes and evaluate a more inclusive diagnostic schema. METHODS: Four VM groups were studied: definite episodic (dVM), probable episodic (pVM), definite chronic (dCVM), and probable chronic (pCVM). Chronic VM was defined as having more than 15 dizzy days per month. Sociodemographic and clinical characteristics were analyzed, along with Dizziness Handicap Inventory (DHI) and Vestibular Migraine Patient Assessment Tool and Handicap Inventory (VM-PATHI) scores. RESULTS: 54 adults with a mean age of 47.0 years (SD 13.7) were enrolled. 10 met criteria for dVM, 11 pVM, 22 dCVM, and 11 pCVM. Overall, there were strong similarities in clinical characteristics between dVM, pVM, dCVM, and pCVM. Compared to subjects with episodic VM, those with chronic VM had a higher average number of VM triggers (8.7 vs. 6.4, P = 0.019), including motion (93.9% vs. 66.7%, P = 0.009), scrolling on a screen (78.8% vs. 47.6%, P = 0.018), skipped meal (57.6% vs. 23.8%, P = 0.015), and air travel (57.6% vs. 23.8%, P = 0.015). They also had higher symptom severity (DHI = 53.3, P = 0.194) and burden of disease (VM-PATHI = 48.2, P = 0.030) scores. CONCLUSIONS: Many patients do not meet current Bárány Society criteria for VM based on their duration of vestibular symptoms. Yet, these patients with chronic VM endorse several indistinguishable symptoms from those who do meet criteria. A more inclusive diagnostic schema should be adopted where patients with vestibular symptoms shorter than 5 minutes or longer than 72 hours are also recognized as having VM.