Odor Provocation Test for Laryngeal Hypersensitivity

Abstract

This study was to present an odor provocation/challenge test for laryngeal hypersensitivity in a suspected odor induced dysphonic patient. The second aim was to rule out secondary gain from organic laryngeal hypersensitivity. Two steps were taken for this purpose. First, because the evaluation of hypersensitivity may be affected by the perception of odor, the study investigated laryngeal hypersensitivity during nasal and oral breathing separately to disentangle possible cognitive reactions to odors. Second, a healthy control (HC) participant was used with the identical testing protocol for nasal breathing to minimize unbiased results. The HC's response to nasal breathing of the odors showed no response to all the stimuli. The participant with possible secondary gain issues responded differently to the odors when presented nasally versus orally. Oral breathing showed less severe and less frequent laryngeal hypersensitive reactions. This suggests that laryngeal hypersensitivity was either due to the odor, cognitive information, sensory changes in olfaction leading to psychological conditioning, or for any possible secondary gain. Hence, it is difficult to indicate the precise reason (cause and effect) for the participant's laryngeal hypersensitivity; however, this study describes the first structured, controlled, repeatable, and randomized design to investigate odor induced laryngeal hypersensitivity and decipher possible secondary gain from true laryngeal hypersensitivity.