Gender differences in chemosensory function

Abstract: This thesis consists of two studies, in which gender differences in nasal chemosensory function are investigated. The first study assesses odor identification ability in a populationbased sample, varying from 45 to 90 yrs, screened for cognitive impairment and severe olfactory dysfunction. Results show that women are generally better than men at identifying odors, but there is no significant interaction of gender by age. Although odoridentification is influenced by semantic memory and cognitive speed, these cognitivefactors are unlikely to cause the observed gender difference in odor identification. The second study investigates chemosensory perception in men and women by assessing eventrelatedbrain potentials, and perceptual ratings for an odorant, which varies inconcentration and olfactory/irritating properties. The results display a generally larger cortical response in women than in men, beginning from about 350 ms after stimulus onset. Women report higher perceived intensity and npleasantness at the highest stimulus concentration, and a steeper psychophysical function, than do men. The results indicatethat stronger cortical responses of nasal chemosensory stimuli provide a neural basis for stronger supra-threshold perception in women than in men, which might enhance odor identification performance. The nature and causes of these gender-differences in nasal chemosensory function are discussed.This thesis for the licenciate degree is based on the following studies:Larsson, M., Nilsson, L-G., Olofsson, J.K., & Nordin, S. (2004). Demographic and cognitive predictors of odor identification: Evidence from a population-based study.Chemical Senses, 29, 547-554.Olofsson, J.K., & Nordin, S. (2004). Gender differences in chemosensory perception andevent-related potentials. Chemical Senses, 29, 629-637.