TASTE SENSITIVITY AND AGING - HIGH-INCIDENCE OF DECLINE REVEALED BY REPEATED THRESHOLD MEASURES

Contrary to what has often been said about the subject, decline in tas te sensitivity with aging characterizes virtually everybody and is not the artificial result of averaging large losses of a minority with ne gligible losses of a majority. This assertion is supported by six repe ated measures of sucrose thresholds in each of 15 older (over 64 years ) and 15 younger (under 27 years) adult subjects. Threshold was determ ined by a procedure similar to past studies and with the same results: much scatter and considerable overlap between the thresholds of young er and older subjects. A quite contrasting picture emerges, however, w hen each subject's six threshold determinations are averaged. Averagin g shrinks the individual differences among subjects, as well as the ov er-lap between younger and older subjects. Although virtually all elde rly subjects now revealed taste weakness, reliable individual differen ces in degree of weakness abound among them, suggesting various indivi dual rates of physiological aging. in contrast, young persons exhibit greater uniformity of sensitivity. These findings were brought out by inter-test correlations, which were much higher for the older subjects ; i.e. an older subject who tended to score high (low) on one test ten ded to score high (low) on the other tests. The study confirms the ten uous nature of brief threshold tests as indices of personal sensitivit y as found earlier also in olfactory thresholds and in concurrent meas urement of two-point touch thresholds In the present study. This revea led correlated losses between repeated taste and touch thresholds from the same 15 older subjects, unrelated to their exact chronological ag e.