The effects of mouth movements, swallowing, and spitting on retronasal odor perception

Although attempts have been made to compare sensations produced by orthonasal and retronasal olfactory stimulation, previous studies have failed to address the dynamic nature of retronasal perception. In this study we demonstrate the importance of oral movements in influencing the perceived retronasal olfactory intensity. For orally-presented solutions of artificial orange and rum extract solutions, average magnitude estimates of eight subjects were significantly increased by various mouth movements (including spitting and swallowing) over a no mouth movement condition. These findings demonstrate that retronasal odor perception is a highly dynamic process, and suggest the hypothesis that mouth movements play a role in retronasal odor perception analogous to that played by sniffing in orthonasal perception. In addition, these data suggest that some disorders of deglutition may have associated chemosensory consequences.