Evaluation of olfaction in patients with migraine using an odour stick identification test

Abstract

Aims: Peculiar characteristics of migraine headaches include the arousal of olfaction during the attacks and osmophobia. We performed an olfactory test to evaluate the association between olfaction and migraines. Methods: We evaluated olfactory dysfunction in 80 migraine patients (31 experienced migraines with aura (MWA), 49 migraine without aura (MWOA)) and 30 healthy controls. Participants were assessed for concurrent osmophobia. Olfaction was evaluated using an odour stick identification test (OSIT), in which participants were asked to identify various odours during a migraine-free period. The degree of offensiveness of each odour was also evaluated. Results: Sixty-three percent of migraine patients were found to have concurrent osmophobia (MWA 71%; MWOA 57%). The percentages of migraine patients and controls who correctly identified test odours were 91% (92%, MWA; 89%, MWOA) and 92%, respectively. Perfume, rose and Japanese cypress odours were more offensive to migraine patients than to controls. All test odours were found to be more offensive to MWA than to MWOA patients. Conclusions: The OSIT showed certain odours to be highly offensive to migraine patients even when they were not experiencing migraine headaches. More attention should be paid to odours that are perceived to be offensive by migraine patients, particularly those with MWA.