SMELL AND TASTE FUNCTION IN THE VISUALLY-IMPAIRED

Surprisingly few quantitative studies have addressed the question of w hether visually impaired individuals evidence, perhaps in compensation for their loss of vision, increased acuteness in their other senses. In this experiment we sought to determine whether blind subjects outpe rform sighted subjects on a number of basic tests of chemosensory func tion. Over 50 blind and 75 sighted subjects were administered the foll owing olfactory and gustatory tests: the University of Pennsylvania Sm ell Identification Test (UPSIT); a 16-item odor discrimination test; a nd a suprathreshold taste test in which measures of taste-quality iden tification and ratings of the perceived intensity and pleasantness of sucrose, citric acid, sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77 sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA) odor detection threshold test. Twenty-three of the sighted subjects were employed by the Phila delphia Water Department and trained to serve on its water quality eva luation panel. The primary findings of the study were that (a) the bli nd subjects did not outperform sighted subjects on any test of chemose nsory function and (b) the trained subjects significantly outperformed the other two groups on the odor detection, odor discrimination, and taste identification tests, and nearly outperformed the blind subjects on the UPSIT. The citric acid concentrations received larger pleasant ness ratings from the trained panel members than from the blind subjec ts, whose ratings did not differ significantly from those of the untra ined sighted subjects. Overall, the data imply that blindness, per se, has little influence on chemosensory function and add further support to the notion that specialized training enhances performance on a num ber of chemosensory tasks.