How to define migraine with brainstem aura?

Sir,

Yamani et al. (2019) reviewed patients with migraine with brainstem aura (MBA) from the literature and from their own study cohorts and concluded that MBA exists, that it is rare and that stricter criteria are required to enhance specificity. For a diagnosis of MBA, they propose to require three instead of the current two brainstem aura symptoms during the attack. We agree and propose an even stricter approach, by combining hearing loss and tinnitus into a single B criterion of auditory features (‘hearing loss and/or tinnitus’) and to keep the requirement to meet three B criteria. Otherwise, a patient with vestibular migraine with attacks of vertigo, with concurrent hearing loss and tinnitus, could easily qualify for a diagnosis of MBA.

Vestibular migraine is a ‘new’ disorder that was included in the appendix for emerging conditions in the Third Edition of the International Classification of Headache disorders [Headache Classification Committee of the International Headache Society (IHS), 2013]. Its acceptance by the scientific community is reflected by 480 PubMed-listed articles for the years 2015 to 2019. Unlike MBA, vestibular migraine is common with a 1-year prevalence estimated at 2.7% in a recent population-based survey in the USA (Formeister et al., 2018). Hearing loss and tinnitus during acute vestibular migraine have been reported in 19% and 52% of 252 vestibular migraine patients, respectively (Teggi et al., 2018) and at similar frequency in several previous papers (Tabet and Saliba, 2017). Thus, counting vertigo, hearing loss and tinnitus as separate criteria for diagnosing MBA may—contrary to the authors’ intention—lead to MBA overdiagnosis. Even patients with Ménière's disease, defined by the triad of vertigo, hearing loss and tinnitus, might be classified as MBA using the current or the proposed criteria as a substantial subgroup have migraine headaches and auras during their vertigo attacks (Radtke et al., 2002), in part because acute vertigo triggers migraine (Seemungal et al., 2006; Murdin et al., 2009).

The criteria for MBA—requiring a brainstem origin to the features—could be made even more stringent by considering the features of vertigo according to their neuroanatomical origin. Specifically, requiring that vertigo be accompanied by visual-world motion (i.e. ‘oscillopsia’) will further improve specificity. This is because brainstem-origin vertigo, like peripheral-origin vertigo, is necessarily associated with an acute nystagmus, which in turn provokes oscillopsia. In contrast, cortical-origin vertigo, e.g. elicited by awake electrical cortical stimulation (Blanke et al., 2000; Kahane et al., 2003), or some cases of cerebellar-origin vertigo, e.g. in acute stroke (Seemungal, 2007), evoke strong vertigo without nystagmus, and hence, without oscillopsia. Requiring that vertigo and oscillopsia both be present does not help distinguish peripheral- and brainstem-origin vertigo; however, the requirement for an additional non-audiovestibular feature in the B criteria should maintain adequate specificity for MBA.

It is quite likely that migraine subtypes represent a spectrum that can be ranked in ascending order as migraine without aura, migraine with aura, vestibular migraine and migraine with brainstem aura. Both for clinical and research purposes we need a consensus on the appropriate delineations.

Data availability

Data sharing is not applicable to this article as no new data were created or analysed in this study.

Funding

B.M.S. is funded by grants from the Medical Research Council (UK), US Department of Defense Congressionally Directed Medical Research Program, The JP Moulton Charitable Foundation, The Racing Foundation, and the NIHR Imperial Biomedical Research Centre.

Competing interests

The authors report no competing interests.