Journal of Clinical Outcomes Management. 2015 October;22(10)
References
Diagnostic Criteria
In 2012, the Committee for Classification of Vestibular Disorders of the Bárány Society and the Migraine Classification Subcommittee of the IHS have jointly formulated the most recent diagnostic criteria for VM [18]. Diagnostic criterion for VM was modelled on the ICHD and is summarised in Table 1 . It is based on recurrent vestibular symptoms, a history of migraine, a temporal association between vestibular symptoms and migraine symptoms, and exclusion of other vestibular conditions [18]. Acute vestibular symptoms that qualify for VM must be of at least moderate or severe intensity which lasts within a time window of 5 minutes to 72 hours and can include various types of vertigo and head motion–induced dizziness with nausea [18]. In patients who have both spontaneous vertigo and head motion–induced symptoms, their episode duration is defined as the total period during which short attacks recur.
Separating VM into 2 diagnostic entities seems particularly useful: definite VM and the more sensitive but less specific category of probable VM. The sensitivity and specificity of the proposed criteria still need to be determined. Although some authors criticize the probable diagnostic entity for its heterogeneity, about 50% of patients initially diagnosed with probable VM ultimately progress to definite VM [12,33]. Definite vestibular migraine appears in the ICHD-3 beta but only in the appendix section for “new disorders that need further research for validation.” However, probable VM will not be included until further evidence of its utility has been accumulated.
The diagnosis is particularly challenging when headache is not a regular accompaniment of the vertiginous attacks. A patient diary may help link migrainous and vertigo symptoms. When headache is not a prominent feature of the attacks, the clinician will have to put migrainous triggers or symptoms such as photophobia or scintillating scotomas in the context of vertigo symptoms to aid with the diagnosis. One needs to be pedantic about differentiating the qualifying symptom of phonophobia, which is defined as a sound-induced discomfort that is often transient and bilateral from the uncomfortable distorted loud sound perception, which occurs with a recruiting sensorineural hearing loss, and is often persistent and unilateral [18]. Response to migraine treatment is not sufficiently specific to be included in the diagnostic criteria. High placebo response rates from migraine trials [34] suggest that placebo effects can likewise be expected in the treatment of VM. Despite these challenges, acceptance of the diagnostic entity of VM seems to be gaining momentum. In a follow-up study over 9 years, the diagnosis remained consistent in 85% of patients [33].
Benign Paroxysmal Vertigo of Childhood and Vestibular Migraine in Children
VM can present at any age, however, the ICHD specifically recognises an early vertiginous entity regarded as a precursor syndrome of migraine in otherwise healthy children called benign paroxysmal vertigo of childhood. This diagnosis requires 5 episodes of severe vertigo, occurring without warning and resolving spontaneously after minutes to hours [35]. In between episodes, neurological examination, audiometry, vestibular functions and EEG must be normal. A unilateral throbbing headache may occur during attacks but it is not a mandatory criterion. It is unclear whether these two conditions in children are the same entity, however it is important to note that the classification of VM does not involve any age limit [18].