Diagnosis requires:
(1) 2 or more attacks fulfilling the criteria of an attack (see below)
(2) exclusion of other causes (see below)
Criteria for BM attack:
(1) aura with 2 or more fully reversible symptoms associated with the posterior circulation (see below)
(2) headache that starts during the aura or afterwards within 60 minutes
(3) one or more of the following:
(3a) each symptom lasts from 5 to 60 minutes
(3b) at least one symptom develops gradually over >= 5 minutes
(3c) different symptoms occur in succession over >= 5 minutes
Key aura symptoms:
(1) dysarthria
(2) vertigo
(3) tinnitus
(4) hyperacusis
(5) diplopia
(6) ataxia
(7) decreased level of consciousness
(8) bilateral paresthesias occurring simultaneously
(9) visual symptoms in both temporal and nasal fields of both eyes occurring simultaneously
Additional aura that may occur (not part of the definition):
(1) reversible aphasia
(2) other sensory symptoms such as numbness
Exclusions:
(1) motor weakness
(2) another disorder that can explain the findings better (lesion in posterior fossa, seizure disorder, another type of migraine, etc).
The presence of vertigo as the only aura symptoms excludes BM but not another form of migraine such as vestibular migraine.
Most patients have onset prior to middle age. Onset after the age of 50 usually is associated with another cause.
