Prevalence of Vertigo, Dizziness, and Migrainous Vertigo in Patients With Migraine

Authors

  • Vlasta Vuković MD,

    1. From the University Hospital “Sestre milosrdnice”—Department of Neurology, Zagreb, Croatia (Drs. Vuković, Galinović, Lovrenčić-Huzjan, Budišić, and Demarin); Children's Hospital Srebrnjak—Research Department, Zagreb, Croatia (Dr. Plavec).
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  • Davor Plavec MD, PhD,

    1. From the University Hospital “Sestre milosrdnice”—Department of Neurology, Zagreb, Croatia (Drs. Vuković, Galinović, Lovrenčić-Huzjan, Budišić, and Demarin); Children's Hospital Srebrnjak—Research Department, Zagreb, Croatia (Dr. Plavec).
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  • Ivana Galinović MD,

    1. From the University Hospital “Sestre milosrdnice”—Department of Neurology, Zagreb, Croatia (Drs. Vuković, Galinović, Lovrenčić-Huzjan, Budišić, and Demarin); Children's Hospital Srebrnjak—Research Department, Zagreb, Croatia (Dr. Plavec).
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  • Arijana Lovrenčić-Huzjan MD, PhD,

    1. From the University Hospital “Sestre milosrdnice”—Department of Neurology, Zagreb, Croatia (Drs. Vuković, Galinović, Lovrenčić-Huzjan, Budišić, and Demarin); Children's Hospital Srebrnjak—Research Department, Zagreb, Croatia (Dr. Plavec).
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  • Mislav Budišić MD,

    1. From the University Hospital “Sestre milosrdnice”—Department of Neurology, Zagreb, Croatia (Drs. Vuković, Galinović, Lovrenčić-Huzjan, Budišić, and Demarin); Children's Hospital Srebrnjak—Research Department, Zagreb, Croatia (Dr. Plavec).
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  • Vida Demarin MD, PhD

    1. From the University Hospital “Sestre milosrdnice”—Department of Neurology, Zagreb, Croatia (Drs. Vuković, Galinović, Lovrenčić-Huzjan, Budišić, and Demarin); Children's Hospital Srebrnjak—Research Department, Zagreb, Croatia (Dr. Plavec).
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  • Conflict of Interest: None

Dr. Vlasta Vuković, University Hospital “Sestre milosrdnice”—Department of Neurology, Zagreb, Croatia.

Abstract

Objective.— The aim of this study was to determine the lifetime prevalence of vertigo and dizziness in patients with migraine as compared with controls and to establish the lifetime prevalence of migrainous vertigo.

Background.— Dizziness and vertigo are relatively frequent complaints in general population; however, the prevalence of migrainous vertigo has not been extensively studied so far.

Methods.— The study included 327 migraine patients and 324 controls who do not suffer from frequent headaches. The study and control group were assessed clinically and through diagnostic workup for having vertigo, dizziness, hypotension, and sideropenic anemia.

Results.— Vertigo or dizziness was experienced by 51.7% of migraine patients (MVL group) and 31.5% in the control group (CVL group), P < .0001. Among the MVL group, 23.2% of patients met the criteria for migrainous vertigo. There was no difference between the MVL group and CVL group in frequency of attacks or the pattern of symptom appearance in relation to head movement. Patients in the MVL group more frequently had hypotension, P = .011. Patients with migraine with aura significantly more often had migraine attacks in association with vertigo or dizziness, P < .0001.

Conclusion.— The lifetime prevalence of migrainous vertigo is relatively frequent in migraine patients, especially in migraine with aura.

Abbreviations:
CVL

control vertigo lifetime

DMV

definite migrainous vertigo

ICHD-II

criteria International Classification of Headache Disorders II criteria

MVL

migraine vertigo lifetime

INTRODUCTION

Headache is one of the most frequent complaints in general practice, and migraine is the second most frequent primary headache.1 Many patients with migraine complain because of dizziness, sense of disequilibrium, and head motion intolerance, or more specific vertigo. Migrainous vertigo has been recognized as a frequent cause of recurrent vertigo in patients presenting to specialized dizziness and headache clinics.2,3 Migraine headaches and vestibular vertigo concur in the general population about 3 times more often than expected by chance.4 An epidemiologic study carried out in general population of adults has shown that the lifetime prevalence of migrainous vertigo is 0.98% and 1-year prevalence 0.89%.4 Since migrainous vertigo is a relatively frequent disorder, it also has a considerable impact both on personal and societal level.4

The aim of this study was to assess the prevalence of vertigo and dizziness in patients with migraine as compared with controls and to establish the prevalence of migrainous vertigo.

METHODS

We have clinically assessed 327 consecutive patients (289 women, 38 men; mean age 39.9 ± 12.2 years) with migraine with or without aura presenting to the Headache clinic between March 2005 and December 2006.

The control group consisted of 324 subjects (263 women, 61 men; mean age 39.8 ± 12.1 years) who had not been diagnosed for having migraine or frequent headaches (no more than one tension-type headache per month); controls were chosen randomly outside the hospital between March and December of 2006. A medical doctor (IG) working as a research fellow at the Neurology Department was trained to perform a face-to-face interview for the identification of subjects for the control group.

Both groups were evaluated for having vertiginous signs and dizziness, time of onset of the symptoms, frequency of the symptoms, and temporal association of the symptoms with the migraine attack. Symptoms of vertigo and dizziness were evaluated according to the proposed criteria for episodic vestibular symptoms of at least moderate severity.2 Additional information concerning the presence of hypotension and anemia in both groups was obtained. Migraine with or without aura was diagnosed according to the International Classification of Headache Disorders II criteria5 during clinical interview by a neurologist, headache specialist (VV); and a clinical neurological examination has been included. When investigating for the presence of dizziness, the study group and control group were specifically asked to describe their symptoms; dizziness symptoms implying non-vestibular dizziness such as orthostatic hypotension were not included. Patients with a history of severe head trauma were not included in the study. Vertigo was not counted as an aura symptom for the diagnosis of migraine with aura. None of these patients fulfilled the International Headache Society (IHS) criteria for basilar migraine. The prevalence of vertigo and dizziness was assessed as lifetime prevalence. The group of patients with migraine who had experienced vertiginous symptoms in their lifetime will be referred to as the MVL group (migraine vertigo lifetime), and subjects in the control group with the experience of vertiginous symptoms in their lifetime as the CVL group (control vertigo lifetime). Migraine patients who met the diagnostic criteria for migrainous vertigo will be referred to as the DMV group (definite migrainous vertigo). Although a diagnostic category of probable migrainous vertigo has been proposed for patients who did not entirely fulfill the criteria for migrainous vertigo,2 in this study, only patients that met the proposed diagnostic criteria for DMV will be referred to as the DMV group.

Although there is no widely accepted criteria for the diagnosis of migrainous vertigo, the diagnosis of DMV in our study was based on the following criteria:2

  • 1Episodic vestibular symptoms of at least moderate severity (rotational vertigo, other illusory self or object motion, positional vertigo, head motion intolerance-sensation of imbalance or illusory self or object motion that is provoked by head motion)
  • 2Migraine according to the IHS criteria
  • 3At least one of the following migrainous symptoms during at least 2 vertiginous attacks: migrainous headache, photophobia, phonophobia, visual or other auras
  • 4Other causes ruled out by appropriate investigations.

In patients in whom dizziness was suspected to be related to orthostatic hypotension, head-up-tilt test was applied as a diagnostic test. Further diagnostic workups such as extracranial color Doppler, transcranial Doppler, brainstem auditory-evoked potentials, magnetic resonance imaging, vestibular tests (calorimetrics), and laboratory tests were performed individually when considered appropriate.

Statistical analysis was performed using the chi-square test and Fisher's exact test to compare proportions. Mean and SD were used to describe continuous variables, and Student's t-test to compare them between different groups and subgroups. STATISTICA release 6.0 (StatSoft Inc., Tulsa, OK, USA) was used for all analyses. < .05 was considered significant.

RESULTS

Patients in the migraine group and controls have not differed significantly in age or gender, because a rather low sample size analysis was not performed according to different age groups. There was a preponderance of women in the sample of migraine group (289 [88.4%] women, 38 [11.6%] men), as was in the control group (263 [81.2%] women and 61 [18.8%] men), P = .065.

The mean age of patients with migraine was 39.9 ± 12.2 years (women 39.9 ± 12.3, men 40.5 ± 11.5), while the mean age of the control group was 39.8 ± 12.1 years (women 39.5 ± 11.5, men 43.0 ± 11.5), P = .86.

The mean number of migraine headaches per month was 3.4 ± 3.3 (in women 3.3 ± 3.3 and in men 3.7 ± 3.0), P = .48. Because the coexistence of tension-type headache was present in a low number of patients, detailed analysis has not been carried out; however, we believe that this could not have influenced the results.

Slightly over half of MVL patients in their lifetime experienced a sense of vertigo or dizziness (169, 51.7%) as compared with the CVL group (102, 31.5%), < .0001. Because of retrospective analysis of vertiginous symptoms, precise etiology could not be established in some patients; therefore, we cannot provide precise data of the percentages of patients suffering from particular vertiginous condition.

In the MVL group, the onset of vertiginous symptoms was earlier than in the CVL group: vertigo or dizziness began 14.6 ± 19.2 years prior to our testing in the MVL group, and 9.9 ± 17.0 years ago in the CVL group; P = .0011. Furthermore, patients were asked to define the time of onset of vertiginous symptoms and they stated as following (MVL vs CVL): (1) from childhood 8 (2.45%) vs 6 (1.85%); (2) symptoms began later in life in 67 (20.49%) vs 54 (16.67%); (3) symptoms began just recently 94 (28.75) vs 42 (12.96%); (4) never had such symptoms 158 (48.32%) vs 222 (68.5%); < .0001.

There was no significant difference between the proportion of patients in the MVL group and CVL group who had symptoms of dizziness or vertigo; in the MVL group, 113 (34.56%) stated that they have dizziness (head motion intolerance-sensation of imbalance or illusory self or object motion that is provoked by head motion) vs 66 (20.37%) in the CVL group while 56 (17.13%) MVL patients stated that they have sense of vertigo (rotational vertigo, other illusory self or object motion, positional vertigo) vs 36 (11.1%) in the CVL group; P = .716.

There was no significant difference between the MVL group and CVL group regarding the appearance of symptoms: vertigo or dizziness appeared in relation only with movement of the head in migraine group in 61 (18.65%) patients vs 39 (12.04%) in controls, and during movement of the head and in a steady state in the MVL group in 100 (30.58%) of patients vs 58 (17.9%) in the CVL group; P = .395.

There was no significant difference between the MVL group and CVL group regarding the frequency of attacks: every or every other day in 14 (4.28%) vs 10 (3.09%), couple of times per month in 85 (25.99%) vs 41 (12.66%) and 1 to 3 attacks of vertigo in lifetime 64 (19.57%) vs 50 (15.43%); P = .185. Results regarding the differences between the MVL group and CVL group, the presence and pattern of symptom occurrence, are shown in Table 1.

Table 1.—. Differences Between MVL and CVL Groups of Patients Regarding the Presence and Pattern of Symptom Occurrence
 MVL (%)CVL (%)P values
  1. CVL = individuals in the control group who had experienced a sense of vertigo or dizziness in their lifetime; MVL = migraine patients who had experienced a sense of vertigo or dizziness in their lifetime.

Number of individuals169 (51.7)102 (31.5)<.0001
 Individuals with vertigo56 (17.13)36 (11.1)<.716
 Individuals with dizziness113 (34.56)66 (20.37) 
Appearance of symptoms in relation to head movement61 (18.65)39 (12.04)<.395
Appearance of symptoms during head movement and in a motionless state100 (30.58)58 (17.9) 
Frequency of attacks
 Every or every other day14 (4.28)10 (3.09)<.185
 A couple of times a month85 (25.99)41 (12.66) 
 1-3 attacks in a lifetime64 (19.57)50 (15.43) 

Vertigo symptoms were associated with a migraine attack always in 38 (22.5%), sometimes in 38 (22.5%), and were not associated in 93 (55.0%). According to the proposed criteria, 76 (23.2%) of migraine patients from our study meet the criteria for DMV.

Migraine without aura (MO) has been diagnosed in 199 (60.9%) patients, while 128 (39.1%) had migraine with aura (MA); patients having MA were regarded as such if they had at least one aura sign. Signs of visual aura were present in 111 (86.7%) MA patients: scintillating scotomata in 73 (57.0%), partial loss of vision in 17 (13.3%), and “vague” vision in 21 (16.4%). Paresthesias in arm or face unilaterally were present in 5 (3.9%) patients and speech problems in 11 (8.6%).

Patients with MA significantly more often have migraine attacks in association with symptoms of vertigo or dizziness: (1) MA always 19 (14.84%) vs MO 19 (9.55%), or (2) MA sometimes 28 (21.88%) vs MO 10 (5.03%); < .0001. The results regarding migraine patients with or without aura are shown in Table 2.

Table 2.—. Differences Between Migraine Patients With or Without Aura
 Migraine with aura (%)Migraine without aura (%)P value
Number of individuals128 (39.1)199 (60.9) 
Always migraine with vertigo/dizziness19 (14.84)19 (9.55)<.0001
Sometimes migraine with vertigo/dizziness28 (21.88)10 (5.03) 

In the migraine group, 83 (25.38%) patients were treated (at present or previously) because of sideropenic anemia, compared with 63 (19.44%) in the control group; 227 (69.42%) individuals in migraine group were never treated compared with 250 (77.16%) in the control group; 17 (5.2%) patients in the migraine group vs 11 (3.40%) patients in the control group had no knowledge regarding the presence of anemia; P = .077. Hypotension was significantly more often found in the migraine group (149, 45.57%) than in the control group (116, 35.80%); P = .011. Data regarding the presence of sideropenic anemia and hypotension are shown in Table 3.

Table 3.—. Differences Between MVL and CVL Groups of Patients Regarding the Treatment of Sideropenic Anemia and the Presence of Hypotension
 MVL (%)CVL (%)P values
  1. CVL = individuals in the control group who had experienced a sense of vertigo or dizziness in their lifetime; MVL = migraine patients who had experienced a sense of vertigo or dizziness in their lifetime.

Sideropenic anemia
 Treated83 (25.38)63 (19.44)= .077
 Not treated227 (69.42)250 (77.16) 
 Does not know17 (5.2)11 (3.4) 
Hypotension
 Present149 (45.57)116 (35.8)= .011
 Not present178 (54.4)208 (64.19) 

DISCUSSION

Studies investigating migraine and vertigo have shown data that support the observation that there is an association between migraine and vertigo, which is not a pure coincidence. However, epidemiologic evidence for this association from control studies is not sufficient as one might expect since migraine has long been associated with vertigo.6,7

The prevalence of migraine worldwide ranges from 6% to 18% in women and 3-6% in men.8-11 Population studies show that the prevalence of dizziness in the general population is over 20%12 and lifetime prevalence of vertigo is 7%.13 A neurology survey has revealed that 3.2% of the general population has both vestibular vertigo and migraine; in that study 1% of the population has been diagnosed as having migrainous vertigo.4 One percent of the population can be expected to have a concurrence of vertigo and migraine by chance if lifetime prevalence of 7% for vertigo and 16% for migraine are taken into account;11,13 so authors4 suggest that the remaining 1% out of the original 3.2% may have probable migrainous vertigo or other vestibular disorders including benign paroxysmal positional vertigo (BPPV) or Meniere's disease since both have been associated with migraine.14-16 In one study, a high proportion of patients (81%) diagnosed as vestibular Meniere's disease had migraine; however, a certain number of these patients might in fact have migrainous vertigo.17

Vertigo has been found to be 3 times more common in migraine patients than in the control group: vertigo occurred in 24-27% of migraine patients compared with controls (8-10%).6,18 However, these studies did not use the IHS criteria for migraine. Our study included only patients with migraine diagnosed according to the revised IHS criteria. The results of our study showed that a significant proportion of migraine patients experienced a sense of vertigo or dizziness in their lifetime: 51.7% as compared with the control group (31.5%; P = .001).

High prevalence of migraine of 30-61% has been found in patients with vertigo.19-21 The lifetime prevalence of DMV was 7% in the dizziness clinic group and 9% in the migraine clinic group; probable migrainous vertigo was found in a further 4% of patients in the dizziness clinic.2 In a retrospective study, 6% of patients presenting to the dizziness clinic had vestibular migraine.22

In our study, vertiginous symptoms began earlier in life in MVL patients than in controls with vertigo (14.6 ± 19.2 years ago vs 9.9 ± 17.0; P = .0011); this may reflect common pathophysiologic pathways in migraine and vertigo.

There was no significant difference between the proportion of patients in the MVL group and the CVL group who had symptoms of dizziness or vertigo; dizziness was more frequently reported by patients (34.56%) than vertigo (17.13%) in the MVL group, as was in the CVL group (20.27%) reported dizziness and (11.1%) reported vertigo. We would like to emphasize that vertiginous symptoms were considered present in patient's history only according to proposed criteria;2 other migraine-related symptoms (eg, “vertigo” due to malaise or vomiting) have been disregarded. Since either vertigo or dizziness provoked by head motion is required for the diagnosis of migrainous vertigo, having either symptom does not make any difference. These data reflect only the preponderance of dizziness in general population as has been observed in studies.12,13

There was no statistical difference between the MVL group and the CVL group regarding the appearance of symptoms: 30.58% of MVL patients had symptoms in a motionless state or during head movement as compared with the control group (17.9%) and only during head movement symptoms were present in the MVL group in 18.65% of patients as compared with 12.04% of controls; P = .395. These data show that more migraine patients have dizziness or vertigo even in a motionless state along with head movement as compared with the controls, which might indicate that in migraine patients additional pathophysiologic pathways may play a role in provoking (and pursuing) such symptoms. Vertical vestibulo-ocular reflex plays an important role in visual stabilization during daily activities such as normal ambulation; in patients with migraine aura and dizziness an abnormal vertical vestibulo-ocular reflex at higher head movement frequencies has been found.23

The majority of MVL and CVL patients in our study have vertiginous symptoms a couple of times per month, although there was no statistical difference between the 2 groups regarding the frequency of attacks: every or every other day 14 (4.28%) vs 10 (3.09%), a couple of times per month 85 (25.99%) vs 41 (12.66%), and 1 to 3 attacks of vertigo in a lifetime 64 (19.57%) vs 50 (15.43%); P = .185.

Vertiginous symptoms may last from seconds, minutes, hours, to even more than a day and in some patients occur on a daily basis.2,24 One study revealed that the majority of patients have short-lasting dizziness attacks (less than 5 minutes) and a minority over a day (3%), which is probably why only one-third of the participants consulted a doctor because of their vertigo;4 this may reflect the causes of underdiagnosis of migrainous vertigo in migraine population.

Studies show that among patients with migrainous vertigo, vertigo was regularly associated with migrainous headache by 24-45%; in 48% vertigo occurred with or without headache and in 2 patients headache and vertigo never occurred together.2,4 Similar findings have been shown in other studies6,25 as well as in our study: vertigo symptoms were associated with a migraine attack always in 38 (22.5%), sometimes in 38 (22.5%), and were not associated in 93 (55.0%). This means that the lifetime prevalence of migrainous vertigo is 23.2% in the population of our migraineurs according to the proposed criteria.

A relatively high proportion (33%) of patients with migrainous vertigo report visual auras, which is not significantly higher than in the group of dizziness-free migraineurs (26%).4 These results regarding visual aura in patients with migrainous vertigo are very similar to ours: significantly more often MA patients have migraine in association with symptoms of vertigo or dizziness: always 19 (14.84%) vs MO patients 19 (9.55%), or sometimes MA 28 (21.88%) vs MO 10 (5.03%); < .0001.

Migrainous vertigo is not sufficiently recognized among clinicians. The diagnosis of migrainous vertigo is not easy, since there may be an overlap of symptoms of different disorders. Migrainous vertigo may present as episodic positional vertigo, and factors that help to distinguish migrainous positional vertigo from BPPV include short-duration symptomatic episodes and frequent recurrences, manifestation early in life, migrainous symptoms during episodes with positional vertigo, and atypical positional nystagmus.25 Another study revealed spontaneous rotational vertigo in 67% of patients with migrainous vertigo and positional vertigo in 24%.4

A study among patients presenting to a neurology dizziness clinic has shown that 31% have BPPV, 20% psychogenic vertigo, 7% DMV and 4% probable, 7% vestibulopathy of unknown origin, 7% neurological gait disorder, 5% Meniere's disease, 5% orthostatic hypotension, 4% central vestibular syndromes, and 3% vestibular neuritis.2 In this study, patients with non-traumatic BPPV of the posterior semicircular canal had a significantly higher prevalence of migraine than controls.

In the IHS classification, there are still lacking criteria for migrainous vertigo; in children benign paroxysmal vertigo of childhood has been recognized and accepted as a separate entity within the IHS classification which affects 2.6% of school children according to a population-based study.26 A recent epidemiological study has shown that the lifetime prevalence of BPPV among adults is 2.4% and the 1-year prevalence is 1.5%; in this study migraine was independently associated with BPPV.27 Basilar migraine has been recognized as a category of migraine with aura that requires at least 2 symptoms originating in the posterior circulation territory and the symptoms should last 5-60 minutes to fulfill the aura criteria, whereas patients with migrainous vertigo have only vestibular symptoms, which puts them in a distinct category. So far, most patients with vertiginous symptoms in epidemiological studies have shown symptoms that were not strictly in temporal relation required for aura, but occurred in various time lengths.

The diagnosis of migrainous vertigo should probably be a distinct entity, because the majority of patients with DMV do not meet all IHS criteria for migraine with aura or basilar migraine, usually because the temporal distribution and length of symptoms do not fulfill the IHS criteria for migraine with aura. Studies have shown that the diagnosis of migrainous vertigo should be given only in cases where all other possible causes of vertigo have been excluded.2

A reason for underdiagnosis of migrainous vertigo may be in part due to the fact that some patients, when their migraine is accompanied by vertigo, have an attenuated headache as compared with their usual migraine attacks.22 The diagnosis of migrainous vertigo in such cases should rely on the presence of accompanying migraine symptoms such as photophobia or phonophobia that are related to the vertiginous attacks of migraine. Detailed history should be taken in patients with migraine and vertiginous symptoms in order to establish a connection if one exists. Making a correct diagnosis in such cases might save doctors' and patients' time and health insurance money because unnecessary diagnostic tests could be avoided. In most cases, a comprehensive diary could help to establish whether migraine and vertigo are related or are separate entities in an individual. Migraine diaries have been proven to help establish a correct diagnosis;28,29 however, similar diaries for the diagnosis of vertiginous disorders are not a standard recommendation in clinical work. Migraine should be easy to diagnose because strict diagnostic IHS criteria have been proposed,5 and if diagnostic uncertainties exist, the diagnosis should be easier to establish after reviewing a diary. However, diagnosing a vertiginous disorder is not always as easy, and unlike migraine, where no specific diagnostic workup is warranted especially in typical cases, in most patients with vertigo certain diagnostic tests should be done in order to exclude more serious causes. In remaining patients who meet the proposed criteria for DMV, a diagnosis can be set. Even though in some patients not all criteria could be fulfilled, a diagnosis of probable migrainous vertigo could be set in order to help guide the therapeutic course.2 Therefore, physicians dealing with patients with migraine and vertigo should not only keep in mind the IHS criteria,5 guidelines for treatment of migraine headaches,30 but also be aware of a relatively high percentage of patients that might in fact have “migrainous vertigo,” rather than 2 separate disorders (ie, migraine and vertigo).

In favor of the fact that migraine and vertiginous symptoms are in association speak studies which have shown that preventive antimigraine therapy is often useful in such patients; however, randomized double-blind studies are needed.24,31,32

The mechanisms of migraine pathophysiology are still not understood; perhaps patients with migrainous vertigo share common pathophysiologic pathways which may help to elucidate the nature of migraine attacks, at least in a subgroup of patients with migrainous vertigo. Hypoplasia of a vertebral artery is found more frequently in migraine patients, especially in migraine with aura, which might at least in part play a role in migraine pathophysiology.33 It is well accepted that migraine is a heterogeneous disorder. Specific forms of migraine, such as familial hemiplegic migraine, have been linked with the mutations in the gene for the α1 subunit component of a voltage-gated calcium channel.34 In some patients with cerebellar dysfunction, a neuronal calcium channelopathy can be detected,35 and because the cerebellum and the vestibular system are connected, these patients often have symptoms originating from the vestibular system. A genetic study performed on 14 genetically unrelated patients with migrainous vertigo has not gained evidence that genes causing familial hemiplegic migraine and episodic ataxia type 2 represent major susceptibility loci for MV.36 Extensive genetic workup is needed, presumably in patients with migrainous vertigo in order to try to establish existence of a genetic background if such exists. In the first place, other causes of vertigo should be excluded, and even then in a relatively small proportion of patients (12.5 to 16.7%) with migraine and vertigo abnormal vestibular function test can been found.21,24 The search for a genetic pattern will not be easy since patients with vertiginous symptoms are probably as heterogeneous as are migraine patients. Still, research is worth a try in a subgroup of such patients.

In some studies, a significant association between migrainous vertigo and coronary heart disease and marginally with diabetes has been found,4 while in others a higher cardiovascular profile has been found among adult migraineurs especially with migraine with aura;37 however, a causal relationship remained unknown. It has also been hypothesized that people with low blood pressure are at higher risk of having migraine attacks or that both manifestations could share a common risk factor, since systolic blood pressure values were found in patients having more frequent migraine attacks.38,39 Results of our study have also shown that migraine patients have hypotension significantly more frequent as compared with people who do not suffer from headaches. When collecting data from patients, special attention was brought to the question regarding orthostatic hypotension, symptoms such as vertigo or dizziness were taken into account if they were not related to symptoms from orthostatic hypotension. The 2 groups did not differ significantly regarding the presence of sideropenic anemia. Because there was no difference in syderopenic anemia between the groups and orthostatic hypotension was ruled out as a cause of dizziness, we believe that these 2 medical conditions could not have influenced our data and that migrainous vertigo is probably related to other, yet unknown mechanisms.

The results of this study have shown that migrainous vertigo affects a significant proportion of patients with migraine and speak in favor of the association between dizziness, vertigo, and migraine, which is even more pronounced in migraine with aura. The shortcomings of this study might be a relatively low study population, the fact that this study is retrospective, and the fact that the patients were not tested for having depressive disorders, which are known to be more present in both patients with migraine and/or vertigo.40

Although there is no gold standard for the diagnosis of migrainous vertigo and further research is needed, we hope that the results of this study will help to establish the criteria for migrainous vertigo that will be helpful to clinicians in their everyday work with patients with migraine and vertigo.

Ancillary