Effects of oral irritation on olfaction

Flavour perception derives from an interplay of the senses that conveys information about the odour, taste, texture, or spiciness of ingested foods. Although interactions between smell and taste have been investigated extensively, we do not know a lot about the effect of oral chemical irritation on odour perception. Therefore, the impact of capsaicin and of carbonated water on four olfactory tasks, i.e., threshold, intensity discrimination, quality discrimination, and intensity ratings was investigated. Since we tested subjects on three different days, order effects were also examined.Intraoral chemesthetic stimulation did not have any effects on olfactory performance. A possible reason for this may be that, in order to interact, stimuli have to be meaningfully associated (congruent meaning) and have to be experienced over the same time course (congruent timing).However, we found an order effect for olfactory stimuli, as intensity ratings of odours differed as a function of when they were tested, which should be considered when doing repeated measures on different days.