The headache component of migraine is perhaps the central defining characteristic – migraine is said to be characterised by attacks of moderate or severe headache with reversible neurological symptoms.[Dodick, 2018; IHS, 2018]
However, the 3rd iteration of the migraine diagnosis criteria of the International Headache Society allows for a diagnosis of migraine without a headache, meaning that an individual may present with the characteristic aura symptoms but not a headache.[IHS, 2018] Although migraine aura without headache is a known clinical entity, it is relatively rare in the migraine population – approximately 4% of people with migraine present with typical aura without headache.[Shah et al., 2018] Clinically, this subpopulation is of great interest, because there may be a reason why the neuropathology underlying aura in these people does not also result in headache.[Shah et al., 2018]
References:
Dodick DW. Migraine. Lancet 2018; 391 (10127): 1315–1330.
Headache Classification Committee of the International Headache Society (IHS). The International Classification of Headache Disorders, 3rd edition. Cephalalgia 2018; 38 (1): 1–211.
Shah DR, Dilwali S, Friedman DI. Migraine aura without headache [corrected]. Curr Pain Headache Rep 2018; 22 (11): 77.