Olfactory Function Assessment of Migraine Patients by Using the Sniffin' Sticks Test: A Clinical Study.

Objective: This as a cross-sectional controlled clinical study. We hypothesis that the olfactory functions in migraine patients may differ from the healthy controls. In this study, we evaluated the olfactory functions by using a Sniffin' Sticks test battery, which is a reliable and semi quantitative test to evaluate for olfactory dysfunction.Methods: Patients above 18 years of age who had migraine received a definitive diagnosis of migraine from experienced headache specialists based on the criteria of The International Classification of Headache Disorders3 were included. Odor threshold, discrimination, and identification parameters were assessed using the "Sniffin' Sticks" test.Results: One-hundred and one migraine patients (age [mean +/- SD], 36.9 +/- 10.4 years; range, 18-60 years) and sixty healthy volunteers (age 34.5 +/- 13.2 years, range 18-65 years) participated in our study. The median odor threshold score [percentiles 25th-75th] was 8.3 [6.5-9.8] for the migraine group during attack free period and 4.5[3.6-6.0] for the control group. It was found that the migraine group had a median odor discrimination score of 10.0 [10.0-13.0] and the control group 12.0 [11.0-13.0]. These differences were statistically significant (p < 0.001 and p = 0.032 respectively). The median odor discrimination and identification scores were statistically significant higher for the participants with higher educational level group than in those of lower educational group (p < 0.0001). The median odor discrimination and identification scores of those without allodynia (12.0 [10.0-14.0] and 13.0 [10.0-13.0] respectively) were higher than that of those with allodynia (11.0 [9.0-12.0] and 11.0 [10.0-13.0] respectively) (p = 0.037 and p = 0.034 respectively).Conclusions: We found that the odor thresholds, discrimination and identification scores of the migraine group demonstrate differences from those of the healthy group and in relation to allodynia.