Abstract
Over the last two decades we who manage dizzy patients have increasingly realized that migraine is an important cause of various forms of episodic vertigo. Although it is one of the most frequent neurological syndromes diagnosed in neurological dizziness units (Table 1), it is still certainly under-diagnosed (1–4). Whether as a function of age (n = 31 085), gender (n = 31 643), or occupational group (n = 31 409), self-reported dizziness accounted for 17.6–39.2% of cases in a large epidemiological investigation and thus is obviously clinically relevant (5). A number of studies have already stressed the association of migraine and vestibular and ocular motor disorders (6–9). Why then is this subject nevertheless so topical that Neuhauser and Lempert (10) have been prompted to provide us with a review that appears in this issue?
The frequency of different vertigo/dizziness syndromes in 4214 patients seen in a neurological dizziness unit (1989–2002)
The answer has to do with the extreme variation of the manifestation of vertigo attacks caused by migraine, especially their duration, lasting from seconds to days, without associated headache in about one-third of the attacks, and their initial manifestation, occurring at any time throughout life (2, 4). This broad spectrum poses a diagnostic problem. Many other causes must be ruled out first, e.g. Menière's disease, transient ischemic attacks, or vestibular paroxysmia due to neurovascular compression, as there is no pathognomonic test available to establish the diagnosis of migraine. It is my experience that the efficacy of migraine prophylaxis in the end usually leads to the appropriate diagnosis, but only after frustrating treatment attempts with betahistamines in suspected cases of Menière's disease, carbamazepine in suspected vestibular paroxysmia, or anti-platelet agents in suspected cases of transient ischemic attacks. In the majority of these patients, however, mild central ocular motor signs such as saccadic pursuit, spontaneous or gaze-evoked nystagmus, and positional nystagmus in the symptom-free interval suggest migraine (2). The channelopathy episodic ataxia type 2 also exhibits interictal nystagmus (11) and saccadic pursuit.
Neuhauser and Lempert (10) give us a thorough and very valuable survey of what is known about the association of migraine with (i) vestibular vertigo, (ii) motion sickness, (iii) cerebellar symptoms, and (iv) non-vestibular dizziness. When it comes to terminology – how to label episodic vertigo that is causally related to migraine – Neuhauser and Lempert (10) propose the term ‘migrainous vertigo,’ to emphasize the particular aetiology of these vertigo attacks. Others have proposed the term ‘vestibular migraine’ to stress the particular manifestation of migraine with vertigo as the prevailing or sole symptom, often even without associated headache (2). The latter term is more orientated to the existing classification of the International Headache Society (IHS).
The authors’ proposal raises other questions. For example, how should we deal terminologically with the two established syndromes of a vestibular manifestation of migraine, i.e. ‘benign paroxysmal vertigo of childhood’ (12) and ‘benign recurrent vertigo’ in adults (13)? I am currently of the opinion that the clearly specified syndrome of ‘benign paroxysmal vertigo of childhood’ as a typical early manifestation of migraine in young children should be kept, because it is distinguished by the following features: usual onset between 1 and 4 years of age, sudden brief vertigo attacks with postural imbalance, anxiety and nausea lasting for seconds to minutes without associated headache, and a spontaneous remission of the attacks within a few years. Basser (12) wrongly described the syndrome as a variety of vestibular neuritis, but Fenichel reported on two siblings in whom the attacks progressively converted into classic migraine (14). Another early manifestation of migraine is ‘benign paroxysmal torticollis in infancy’ (15) with onset in the first year of life and spontaneous recovery before 5 years of age. In its recurrence, duration, benign course, and close association with migraine it resembles ‘benign paroxysmal vertigo of childhood’ (16), which recently has been shown to be linked to CACNA1A mutation (17).
We can manage quite well without the term ‘benign recurrent vertigo’ in adults, because this disease entity is sufficiently covered by ‘vestibular migraine’ with/or without accompanying headache. Finally, there is an association of migraine with benign paroxysmal positional vertigo and Menière's disease. Although statistically confirmed, it still awaits the establishment of a convincing pathophysiological link.
Neuhauser and Lempert (10) rightly draw our attention to the fact that whether called ‘migrainous vertigo’ or ‘vestibular migraine,’ this entity is missing from the extensive official classification of the IHS despite its frequency and clinical relevance. It remains an open question, however, if the addition of this chameleon will lead to more clarity or more confusion.
Footnotes
Acknowledgements
I thank J Benson for copy-editing the manuscript.