Individual differences in the quantitative and qualitative responses of human subjects to various odors

Abstract
The diastereoisomeric ketone, cis-4-(4′-t-butylcyclohexyl)-4-mcthyl-2-pentanone (pemenone), shares with 5α-androst-16-en-3-one (androstenone) a pronounced urine-sweaty odor. A specific anosmia for this latter compound has been described. We obtained quantitative and qualitative odor reports from selected human subjects who were presented with various concentrations of these two compounds in order to determine if subjects were likely to rate them in a uniform fashion. We also estimated the generality of these results by evaluating different concentrations of a small number of other compounds for which specific anosmias have been described. Several hundred subjects were screened with a moderate concentration of pemenone (375 ¨M). Of those screened, 38% reported some odor quality and 47% of those chose an unne-like descriptor. A total of 39 subjects were examined in detail, 54% of these were initially classified as anosmic for the intense urine-sweaty odor of pemenone. The subjects produced magnitude estimates and quality reports for controls and various concentrations of eight different compounds. A principal-components factor analysis of the ranked intensity scores resulted in a four-component solution. The responses to pemenone were significantly correlated with the estimates and reports for androstenone. It was also clear that the odor descriptors for both materials were clustered into several distinct categories for those subjects judged to be anosmic for the urinous note. These data suggest that different processes are activated during the detection of these odors and that a specific anosmia results when one of these processes is reduced or absent.