4.2. Phenotyping
numbing, stinging, taste sensations, sneeze, throat, cough, palate, epiglottis
Using a double-blind study design, panelists were tested in closed rooms designed specifically for sensory testing, with red light illumination to eliminate the effect of the color of the solution, if any, on sensory ratings. During the first session, panelists were trained individually to identify basic taste sensations and were familiarized with rating taste and irritation sensations on the general labeled magnitude scale (gLMS) and palatability on the hedonic gLMS, on a computer with Compusense five™ Plus software (version 5) (Compusense, Inc., Guelph, Ontario, Canada). The gLMS visually spaces verbal descriptors of intensity for chemosensory perceptions (e.g., bitterness, sweetness, and irritation) as no sensation (0), barely detectable (1.4), weak (5.8), moderate (16), strong (35), very strong (53), and strongest imaginable (100) [After swishing it in their mouth for 5 s, panelists rated taste, irritation, and palatability on a computer. One minute separated the presentation of each stimulus, during which panelists rinsed their mouths with water. Stimuli were presented in a quasi-randomized order since during the sessions in which they rated the ibuprofen medicine, it was presented last since it was the only stimulus that was swallowed. This formulation was evaluated under three conditions and in the following order: (a) swishing in mouth for 5 sec and spitting out without swallowing (sip-and-spit condition); (b) after a one-minute pause, swishing in the mouth for 5 sec and then swallowing (swallow condition); and (c) five minutes post-swallowing (delay condition). Immediately after rating the intensity of taste, irritation, and hedonics, panelists were presented with a checklist of eight chemesthetic sensations—burning, tingling, stinging, numbing, cooling, scratching, urge to cough, and urge to sneeze—and indicated which, if any, they experienced. They were then presented with a diagram of the sagittal section of the head and throat areas (i.e., tongue, hard palate, soft palate, oropharynx, nasopharynx, hypopharynx, larynx, trachea, esophagus, and epiglottis as shown in 