Smell Sensitivity in Chronic Migraine: A Case-Control Study

Olfactory impairment is a common symptom of neurologic disorders and may be related to dopaminergic dysfunction. Studies show that patients with migraine show increased sensitivity to light and sound. In our previous study in episodic migraineurs, olfaction was similar to age and sex-matched controls outside of attacks, but lower during acute attacks. The hypothesis is that olfactory function in chronic migraine (CM) will have mild impairment of olfaction at baseline but a more significant impairment during migraine or headache exacerbations. The investigators have two objectives: * To determine baseline olfactory acuity in subjects with CM and compare them to age and sex-matched controls * To determine how olfaction changes during acute exacerbations of migraine in those with CM To execute this study, the investigators will interview subjects and controls to ensure that they meet inclusion and exclusion criteria. After obtaining informed consent, subjects and controls will complete a questionnaire survey regarding their history or lack of history of headaches, smell sensitivity, osmophobia and current medication use and answer questions about attack frequency, location of headache, duration of disease, use of medication for pain, and disability. Both migraineurs and controls will take the University of Pennsylvania Smell Identification Test (UPSIT) in the office. After the first visit, migraineurs and controls will self-administer the UPSIT at home. They will be required to return the second test to the Jefferson Headache Center. The investigators will use analysis of variance (ANOVA) to determine variance in UPSIT scores between subjects and controls. To achieve a 90% power that the study will detect a statistically significant difference between the mean UPSIT scores at a two-sided 5 percent significance level, our sample size for both subjects and controls is 50.