Subtypes of vestibular migraine
Reviewed by Victor Osei-Lah

The authors argue that the current Barany criteria (ICVD) for vestibular migraine (definite and probable – dVM and pVM) are too restrictive. For instance, whereas a category of chronic migraine with or without aura is recognised in ICHD-3, ‘chronic VM’ does not exist in the Barany criteria. Moreover, the ICVD does not take into account family history of migraine and several well-recognised triggers. They proposed two chronic subtypes: definite chronic vestibular migraine (dCVM) and probable chronic vestibular migraine (pCVM). ‘Chronic’ is defined as the presence of vestibular symptoms for more than 15 days per month in patients who had a history of migraine headache and co-occurrence of chronic vestibular symptoms and chronic migraine, with or without aura, thus aligning with the ICHD definition of chronic migraine. To test their clinical observation, a prospective study was designed for new patients attending a tertiary neuro-otology clinic over a period of 14 months. In addition to completing questionnaires for disease severity (DHI) and burden (VM-PATHI), data on migraine history and type, duration and frequency of dizziness, dizziness triggers (15 in total), and associated symptoms during dizziness, was collected. Of the 54 adults enrolled, 10 met the criteria for dVM, 11 pVM, 22 dCVM, and 11 pCVM, i.e. 33 patients in the chronic groups. Although there were characteristic features in common to all four groups, several patients did not fulfil the ICVD criteria; for instance, the duration of the vestibular symptoms was either shorter than five minutes (7/54) or far exceeded the 72-hour cutoff point (20/54). The most interesting findings distinguishing the episodic from the chronic subtypes were the triggers. Chronic VM had statistically significantly more triggers on average than episodic VM (8.7 vs 6.4, p=0.019), the notable ones being 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). A history of motion sickness was most common in the dCVM group. It goes without saying that both disease severity and burden were greater in the chronic subtypes. The authors highlighted several other findings that exposed the deficiencies in the ICVD criteria: 10.0% of subjects in dVM and 27.3% in pVM experienced their most common vertigo lasting less than five minutes or greater than 72 hours, yet all fulfilled the frequency and duration of vestibular symptoms required for VM; 59.1% with dCVM and 90.9% with pCVM would not have met the criteria for VM based on symptom duration. The average number of associated symptoms such as light and sound sensitivity, headache, pressure in ears and head, was identical in all groups. The authors conclude that adhering to the current ICVD criteria leaves many VM patients underdiagnosed. This is certainly my observation too. I suspect many neuro-otologists would agree that diagnostic criteria, although useful, should be supplemented by the equally valuable clinical judgement and experience in guiding diagnosis and management.

Broadening vestibular migraine diagnostic criteria: A prospective cohort study on vestibular migraine subtypes.
Chae R, Krauter R, Pasquesi LL, Sharon JD.
J VESTIB RES
2022;32(5):453-63.