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6.1 Introduction

The interrelations of vertigo and migraine are increasingly recognized by the medical community. The number of published papers on vestibular migraine (VM) has rocketed in the last decades. A PubMed search using the term “migraine” and “vestibular” yields 10 hits before 1980, 70 between 1980 and 2000 and 310 since then. That migraine may present with attacks of vertigo has been noted from the early days of neurology [1]. Starting with Kayan and Hood’s classical paper [2], the clinical features of VM have been well elucidated in several large case series [3–9]. Various terms have been used to designate vertigo caused by a migraine mechanism including migraine-associated vertigo, migraine-associated dizziness, migraine-related vestibulopathy, migrainous vertigo, benign recurrent vertigo and basilar migraine. Vestibular migraine has been convincingly advocated as a term that stresses the particular vestibular manifestation of migraine and thus best avoids confounding with non-vestibular dizziness associated with migraine [10]. Therefore, the Bárány Society and the International Headache Society (IHS) have opted for vestibular migraine in their recent joint paper on the classification of the disorder [11].

6.2 Diagnostic Criteria for Vestibular Migraine

In the previous International Classification of Headache Disorders (ICHD-2), vertigo was not included as a migraine symptom in adults except in the framework of basilar-type migraine [12], which leads to vertigo in more than 60 % of the patients [13]. As an aura symptom of basilar-type migraine, vertigo should last between 5 and 60 min and should be followed by migraine headaches. In addition, at least one more aura symptom from the posterior circulation is required. Less than 10 % of patients with VM fulfilled the criteria for basilar-type migraine [5–8], which makes basilar-type migraine an inappropriate category for most of these patients.

Therefore, the Bárány Society, which represents the international community of basic scientists, otolaryngologists and neurologists committed to vestibular research, mandated a classification group to develop diagnostic criteria for VM. The draught of the classification was extensively discussed with the Migraine Classification Committee of the International Headache Society, which resulted in a joint document defining vestibular migraine and probable vestibular migraine [11]. These criteria have been included in the third edition of the International Classification of Headache Disorders (ICHD-3), published in 2013 [14]. VM appears in the appendix for new disorders that need further research for validation. In addition, the classification of vestibular migraine is part of the evolving Classification of Vestibular Disorders of the Bárány Society. The new ICHD-3 includes only vestibular migraine, while the Bárány classification also contains probable vestibular migraine (Table 6.1).

Table 6.1 Diagnostic criteria for vestibular migraine
Full size table

6.3 Prevalence of Vestibular Migraine

Vestibular migraine was diagnosed in 7 % in a group of 200 dizziness clinic patients and in 9 % of 200 migraine clinic patients [8]. In a population-based study (n = 4,869) with screening interviews followed by expert telephone interviews, the lifetime prevalence of VM was estimated at 0.98 % (95 % CI 0.7–1.37) [18]. Of note, VM accounted for only a third of migraine patients with a history of vertigo, which indicates the need for a thorough neuro-otological workup for exclusion of other diagnoses [18]. In a community-based sample of middle-aged women in Taiwan, VM was identified in 5 % and in 30 % of those with migraine [19]. VM is still widely underdiagnosed, as shown by a study from a dizziness clinic in Switzerland, where VM accounted for 20 % of the diagnoses in young patients, but was suspected by the referring doctors in only 2 % [20] (for an extensive review on epidemiology of VM, see Chap. 5 in this volume).

6.3.1 Demographic Aspects

VM may occur at any age [4, 5, 7]. It is more common in women with a reported female to male ratio between 1.5 and 5 to 1 [5–8]. Familial clustering may occur, probably based on an autosomal dominant pattern of inheritance with decreased penetrance in men [21]. In most patients, migraine begins earlier in life than VM [7, 8]. Some patients have been free from migraine attacks for years when VM first manifests itself [7]. Not infrequently, vertigo attacks replace migraine headaches in women around menopause.

6.4 Vestibular Migraine in Children

Benign paroxysmal vertigo of childhood is an early manifestation of VM which is recognized by the ICHD [14]. It is characterized by brief attacks of vertigo or disequilibrium, anxiety and often nystagmus or vomiting, recurring for months or years in otherwise healthy young children [22]. Many of these children later develop migraine, often years after vertigo attacks have ceased [23]. A family history of migraine in first-degree relatives is twofold increased compared to controls [24]. The prevalence of recurrent vertigo probably related to migraine was estimated at 2.8 % in children between 6 and 12 years in a population-based study [24].

6.4.1 Symptoms

6.4.1.1 Types of Vertigo

Patients with VM typically report spontaneous or positional vertigo. Some experience a sequence of spontaneous vertigo transforming into positional vertigo after several hours or days. This positional vertigo is distinct from benign paroxysmal positional vertigo (BPPV) with regard to duration of individual attacks (often as long as the head position is maintained in VM versus seconds only in BPPV), duration of symptomatic episodes (minutes to days in VM versus weeks in BPPV) and nystagmus findings [25]. Altogether, 40–70 % of patients experience positional vertigo in the course of the disease, but not necessarily with every attack. A frequent additional symptom is head motion intolerance, i.e. imbalance, illusory motion and nausea aggravated or provoked by head movements [5, 26]. Visually induced vertigo, i.e. vertigo provoked by moving visual scenes such as traffic or movies, can be another prominent feature of VM [5, 27]. Nausea and imbalance are frequent but nonspecific accompaniments of acute VM. The combination of different types of vertigo distinguishes VM from other neuro-otological disorders such as benign paroxysmal positional vertigo or Menière’s disease, which typically present with monosymptomatic vertigo. Patients with VM are often affected by motion sensitivity even in-between attacks [28], which may lead to a chronic type of vestibular dizziness [25]. Another factor contributing to chronic vestibular migraine is secondary psychiatric morbidity, particularly anxiety disorders [29, 30]. These two components of interictal dizziness may not be easily discriminated in individual patients [31].

6.4.1.2 Relation to Headaches

VM often misses not only the duration criterion for an aura as defined by the ICHD but also the temporal relationship to migraine headaches: 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 experience attacks both with and without headache [4, 6, 7]. Quite frequently, patients have an attenuated headache with their vertigo as compared to their usual migraine [3, 6]. In some patients, vertigo and headache never occur together [4, 6, 8]. Misdiagnosis of VM as “cervical vertigo” may occur when accompanying pain is mainly or exclusively localized in the neck, which is quite common in patients with migraine [32].

6.4.1.3 Other Symptoms

Along with the vertigo, patients may experience photophobia, phonophobia, osmophobia and visual or other auras. These phenomena are of diagnostic importance, since they may represent the only apparent connection of vertigo and migraine. Patients need to be asked specifically about these migraine symptoms since they often do not volunteer them. A dizziness diary can be useful for prospective recording of associated features.

Auditory symptoms, including hearing loss, tinnitus and aural pressure, have been reported in up to 38 % of patients with VM [2, 5, 6, 33, 34]. Hearing loss is usually mild and transient, without or with only minor progression in the course of the disease [6]. About 20 % develop mild bilateral downsloping hearing loss over the years [35]. In contrast, unilateral moderate to severe hearing loss starting in the low-frequency range would rather favour a diagnosis of Menière’s disease.

6.4.1.4 Precipitating Factors

Asking for migraine-specific precipitants of vertigo attacks may provide valuable diagnostic information, e.g. provocation by menstruation, deficient sleep, excessive stress, skipped meals, lack of fluid and exposure to sensory stimuli, such as bright or scintillating lights, intense smells or noise. The influence of specific foods and weather conditions is probably overestimated. Sometimes, migraine accompaniments and typical precipitants may be missing, but VM is still considered the most likely diagnosis after other potential causes have been investigated and appear unlikely. In this case, a favourable response to antimigraine drugs may support the suspicion of an underlying migraine mechanism. However, apparent efficacy of a drug should not be regarded as a definite confirmation of the diagnosis, since spontaneous improvement, placebo response and additional drug effects (e.g. anxiolytic or antidepressant) have to be taken into account.

6.5 Findings on Clinical Examination

In most patients, the general neurologic and otologic examination is normal in the symptom-free interval [4]. Neuro-ophthalmological evaluation may reveal mild central ocular motor deficits such as persistent positional nystagmus and saccadic pursuit, particularly in patients with a long history of VM [7, 35, 36]. Interictal head-shaking nystagmus was observed in 50 % of VM patients [37]. In one study, patients with VM became nauseous after caloric testing four times more often than migraine patients with other vestibular disorders [38]. A neuro-otologic study of 20 patients during the acute phase of VM showed pathological nystagmus in 14 patients, mostly central spontaneous or positional nystagmus. Three patients had a peripheral type of spontaneous nystagmus and a unilateral deficit of the horizontal vestibuloocular reflex. Imbalance was observed in all patients except one [39]. Another study confirmed the high prevalence of persistent positional nystagmus, which was often horizontal and direction changing, but could also beat in the vertical or torsional plane [40].

Vestibular testing in the interval can be useful to reassure patient and doctor that there is no severe abnormality, such as a complete canal paresis which would rather suggest another diagnosis. MRI is required in patients presenting with central abnormalities and no previous history of similar attacks. Audiometry helps to differentiate VM from Menière’s disease. In clinical practice, history will usually provide more clues for the diagnosis than vestibular testing, since there are no abnormalities which are specific for VM. Therefore, in patients with a clear-cut history, no additional vestibular tests are required (for details on vestibular testing abnormalities, see Chap. 7 in this volume).

6.6 Differential Diagnosis

The differential diagnosis of vestibular migraine includes other disorders causing spontaneous and positional vertigo. Again, history taking provides more valuable clues than technical procedures, which rather serve to provide further evidence for or against a clinical working diagnosis.

6.6.1 Menière’s Disease

The interrelation of migraine with Menière’s disease may cause particular diagnostic problems. Migraine is more common in patients with Menière’s disease than in healthy controls [41]. Patients with features of both Menière’s disease and vestibular migraine have been repeatedly reported [41, 42]. In fact, migraine and Menière’s disease can be inherited as a symptom cluster [43]. Fluctuating hearing loss, tinnitus and aural pressure may occur in vestibular migraine, but hearing loss does not progress to profound levels [6, 44]. Similarly, migraine headaches, photophobia and even migraine auras are common during Menière’s attacks [41, 45]. The pathophysiological relationship between vestibular migraine and Menière’s disease remains uncertain. In the first year after onset of symptoms, differentiation of vestibular migraine from Menière’s disease may be challenging, as Menière’s disease can be monosymptomatic with vestibular symptoms only in the early stages of the disease. When the criteria for Menière’s disease [46] are met, particularly hearing loss as documented by audiometry, Menière’s disease should be diagnosed, even if migraine symptoms occur during the vestibular attacks. Only patients who have two different types of attacks, one fulfilling the criteria for vestibular migraine and the other for Menière’s disease, should be diagnosed with the two disorders. A future classification of VM may include a vestibular migraine/Menière’s disease overlap syndrome [34].

6.6.2 Benign Paroxysmal Positional Vertigo (BPPV)

VM may present with purely positional vertigo, thus mimicking BPPV. Direct nystagmus observation during the acute phase may be required for differentiation. In vestibular migraine, positional nystagmus is usually persistent and not aligned with a single semicircular canal. Symptomatic episodes tend to be shorter with vestibular migraine (minutes to days rather than weeks) and more frequent (several times per year with VM rather than once every few years with BPPV) [25].

6.6.3 Transient Ischemic Attacks (TIAs)

A differential diagnosis of vertebrobasilar TIAs must be considered particularly in elderly patients. Suggestive features include vascular risk factors, coronary or peripheral atherosclerosis, sudden onset of symptoms, total history of attacks of less than 1 year and angiographic or Doppler ultrasound evidence for vascular pathology in the vertebral or proximal basilar artery.

6.6.4 Vestibular Paroxysmia

Vestibular paroxysmia is a controversial disorder, presumably caused by vascular compression of the vestibular nerve. The presenting feature is brief attacks of vertigo, lasting from one to several seconds, which recur many times per day. Successful prevention of attacks with carbamazepine supports the diagnosis.

6.6.5 Psychiatric Dizziness Syndromes

Anxiety and depression may cause dizziness and likewise complicate a vestibular disorder. Anxiety-related dizziness is characterized by situational provocation, intense autonomic activation, catastrophic thinking and avoidance behaviour. More than 50 % of patients with VM have comorbid psychiatric disorders [47].