In the past half-century, the number of Americans 65 years of age and older has increased from approximately 3,000,000 to more than 14,000,000 and, it is estimated, will reach 21,000,000 by 1975. This increase does not reflect merely an increase in total population, since our "senior citizens" are becoming a larger proportion of the total population.
The physiologic loss of hearing acuity in older persons brings with it a number of problems. Among these are the difficulties in distinguishing hearing losses due to presbycusis from losses associated with long exposure to intense industrial noise and the psychological disturbances often associated with advanced presbycusis. The frequent inadequacy of present-day hearing aids in the management of deafness due to presbycusis is also an important problem.
These problems have been investigated in a number of ways. Crowe, Guild, and Polvogt,1 and Schuknecht2 have studied both animals and humans to correlate certain