Empty nose syndrome: limbic system activation observed by functional magnetic resonance imaging.

OBJECTIVES/HYPOTHESIS Empty nose syndrome (ENS) patients have a persistent sense of impaired nasal patency despite radical resection of nasal turbinates. The aim of this study was to elucidate differences in cerebral activation during free breathing and after inhalation of a fragrance (lemonene) and a pseudodecongestant (menthol) over a nasofacial mask. Our hypothesis was that menthol would be perceived as beneficial and that cerebral activation would show differences in areas corresponding to emotional suffering and air hunger in ENS patients. STUDY DESIGN Prospective, controlled intervention with lemonene and menthol during functional magnetic resonance imaging (f-MRI) experiment. METHODS Ten right-handed ENS patients were compared to 15 controls using f-MRI and fully automated data analysis with SPM software. Nasal patency was measured with rhinomanometry and rated on a four-point scale. RESULTS Despite similar objective nasal flow, ENS patients rated nasal patency significantly worse than did controls. Menthol was perceived to increase nasal patency. In patients, f-MRI data showed different activation of temporal cortex areas after inhalation of menthol. The comparison of patients and controls showed ENS-specific activation of temporal and cerebellar areas and amygdala during the rating task itself. CONCLUSIONS Our experiments showed different cerebral processing of the feeling of nasal patency in ENS patients with prominent activation of areas belonging to the limbic system. The beneficial effect of menthol seems to correspond to activation differences in the temporal pole. These results demonstrate a neuronal substrate for both symptoms and their relief in ENS patients.