Migraine can manifest as attacks of recurrent vertigo either spontaneous or positional, lasting seconds to days. Vestibular migraine is an evolving entity and therefore various terms like migraine-associated vertigo, migraine-associated dizziness, migraine-related vestibulopathy, migrainous vertigo, benign recurrent vertigo, and basilar migraine, are probably used to the same patient population. The term basilar migraine, however, should be restricted to patients who fulfill the diagnostic criteria of the International Headache Society (IHS) for basilar migraine.
Diagnostic criteriaIn the current IHS classification, vertigo is not included as a migrainous symptom in adults except for the basilar migraine which considers vertigo as an aura symptom of basilar migraine that should last between 5 and 60 minutes and is followed by migrainous headache. Besides this, a second aura symptom from the posterior circulation should be reported. In fact, less than 10% of patients who have vestibular migraine in published case series fulfill the criteria for basilar migraine thus making basilar migraine an unclassifiable category for these patients. As a consequence, most adult patients who have vestibular migraine cannot be classified with the current IHS criteria.
Clinical features Demographic AspectsVestibular migraine may occur at any age and has female preponderance, with a reported female-to-male ratio between 1.5 and 5 to 1. It probably follows an autosomal dominant pattern of inheritance with decreased penetrance in men. In most patients, migraine begins earlier in life than vestibular migraine and some have been free from migraine attacks for years when vestibular migraine first manifests itself. In some women migraine headaches are replaced by vertigo attacks around the time of menopause. Vestibular migraine seems to occur more often in patients who have migraine without aura than in patients who have migraine with aura.
Vestibular migraine in Children
Benign paroxysmal vertigo of childhood is an early manifestation of vestibular migraine that is recognized by the IHS classification of headaches.
Clinical Presentation in adults
Patients with vestibular migraine typically report spontaneous or positional vertigo. In some patients there is a continuum of spontaneous vertigo transforming into positional vertigo after several hours or days. This positional vertigo is distinct from BPPV with regard to duration of individual attacks ( it lasts often as long as the head position is maintained in Dix-Hallpike position in vestibular migraine versus seconds only in BPPV), duration of symptomatic episodes (minutes to days in vestibular migraine versus weeks to months in BPPV), and nystagmus findings. Approximately 40-70% of patients experience positional vertigo in the course of the disease but not invariable with every attack. Head motion intolerance, quite similar to motion sickness (imbalance, illusory motion or nausea aggravated or provoked by head movements) and visual vertigo (vertigo provoked by moving visual scenes, such as traffic or cinema) are two other prominent feature of vestibular migraine. Nausea and imbalance are frequent but nonspecific accompaniments of acute vestibular migraine. The duration and frequency of attacks can vary between patients and in individual patients over time. The duration of vertigo ranges from seconds (approximately 10%) and minutes (30%) to hours (30%) and several days (30%). Some patients take weeks to recover fully from an attack. The attacks may occur days, months, or even years apart in an irregular fashion. Overall, only 10-30% of patients have vertigo with the typical duration of a migraine aura (5–60 minutes). Vestibular migraine often doesn’t fulfill the duration criterion for an aura as defined by the IHS but the temporal relationship to migraine headaches is also not maintained. The vertigo can precede headache, as would be typical for an aura; may begin with headache; or may appear late in the headache phase. Many patients may experience attacks with headache at one time and without headache at some other time. In some patients, vertigo and headache never occur together and in these cases, diagnosis is based on migrainous symptoms during the attack other than headache. Along with the vertigo, patients may experience photophobia, phonophobia, osmophobia, and visual or other auras. These epiphenomena are important to be clearly sought for during history taking because they may represent the only apparent connection of vertigo and patients often do not volunteer them. Hearing loss and tinnitus are not prominent symptoms of vestibular migraine but have been reported in individual patients who have vestibular migraine. Hearing loss is usually mild and transient, without progression in the course of the disorder. However, patients with severe fluctuating hearing loss suggestive of meniere's disease and migrainous features during the attack implying vestibular migraine have been reported. Asking for migraine-specific precipitants of vertigo attacks may provide valuable diagnostic information (menstruation,deficient or irregular sleep, excessive stress, specific foods such as matured cheese, red wine, monosodium glutamate and finally, sensory stimuli, such as bright or scintillating lights, intense smells, or noise). In some patients migrainous accompaniments and typical precipitants may be missing, but vestibular migraine is considered the most likely diagnosis after other potential causes have been investigated and ruled out. In such a situation, a favorable response to antimigraine drugs supports the suspicion of an underlying migraine mechanism. However, apparent efficacy of a drug cannot be regarded as an absolute confirmation of the diagnosis because spontaneous improvement, placebo response and co-prescribed drug effects (anxiolytic, antidepressant) have to be taken into account.
Clinical and Neurotologic Findings in Patients who have Vestibular migraine
In most patients, the general neurologic and otologic examination is normal in the symptom-free period. Approximately 10-20% of patients with vestibular migraine have unilateral hypoexcitability to caloric stimulation and approximately 10% have directional preponderance of nystagmus responses. These findings are not specific for vestibular migraine because they can be found in migraine patients who do not have vestibular symptoms and in many other vestibular syndromes. Neuro-ophthalmologic examination during attack-free period reveals that more than 60% of vestibular migraineurs show slight central ocular motor disorders e.g. gaze-evoked nystagmus, saccadic smooth pursuit, horizontal or vertical spontaneous nystagmus or central positional nystagmus. The latter is always persistent as long as the provoking position is maintained and was usually do not beat in the plane of positioning, unlike the benign paroxysmal positional nystagmus. In clinical practice, history usually provides more clues for the diagnosis than vestibular testing, because there are no abnormalities that are specific for vestibular migraine. Therefore, in patients with a clear-cut history, no additional vestibular tests are required.
Treatment
In many patients, vestibular migraine attacks are severe, long, and frequent enough to warrant acute or prophylactic treatment. Unfortunately, current treatment recommendations are based on expert opinion rather than on solid data from randomized placebo-controlled trials. It is suggested that medications used for migraine prophylaxis may be effective, including propranolol, metoprolol, tricyclic antidepressants, divalproex sodium, topiramate and flunarizine. The carboanhydrase inhibitors acetazolamide and dichlorphenamide, which are not normally used for migraine prophylaxis, have also been used successfully. Expected side effects, such as orthostatic hypotension with beta-blockers or weight gain with divalproex sodium, influence the selection of the drug. The patients with vestibular migraine are advised to monitor the frequency and severity of their attacks in a diary. Treatment response should be evaluated after 3 months. A greater than 50% reduction in attack frequency is a reasonable goal. Treatment of acute vestibular migraine with acute migraine medication can be attempted with triptans and vestibular suppressants, such as promethazine, dimenhydrinate, and meclizine. Nonpharmaceutic approaches in the treatment of vestibular migraine should not be neglected and may be even more effective than drugs in individual patients. A thorough explanation of the migrainous nature of the attacks can relieve unnecessary fears. Avoidance of identified triggers, regular sleep and meals and regular exercise has a definite role in migraine prophylaxis.
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