Ability of gum flavors to distract participants from painful stimuli: Differential effects of retronasal vs. orthonasal scent administration.

Abstract

Research has shown that peppermint and cinnamon odors significantly increase physiological arousal, cognitive performance, and physical performance in humans, as well as increase pain tolerance in both mice and humans. More recently, the route of administration of these scents has been found to play a key role in producing such effects. For example, orthonasal (through the nose) scent administration augments levels of alertness and leads to increased cognitive processing; however, effects observed during retronasal (through the mouth) administration are significantly less powerful. The present study assess the efficacy of retronasal odorant administration on pain threshold and tolerance. In a within-subjects design, participants completed the protocol under five conditions: cinnamon gum, peppermint gum, flavorless gum, sham chewing, and a control condition. Participants experienced the conditions for 10 min prior to and during a cold pressor test. Following the cold pressor test, participants completed questionnaires related to mood (Profile of Mood States) and workload (NASA-Task Load Index). Despite past research indicating pain tolerance and threshold effects from orthonasal stimuli, the retronasal stimuli in the present study failed to replicate such effects. Thus, route of odorant administration is an important consideration in promoting pain relief.