Speech Communication by Younger and Older Adults: The Effects of Age-Related Vocal Changes, Environmental Noise and Simulated Listener Demands

Age-related changes in both speech and hearing can affect communication. While it is well-known that age-related declines in hearing affect speech understanding, especially in difficult situations such as noisy environments, few studies have investigated how age-related changes in speech production can affect communication in adverse conditions. Strategies such as clear speech may be employed, but they have mostly been examined in younger talkers, so little is known about how well older talkers can adjust to difficult conditions. The experiments in this thesis showed that speech and voice characteristics change with normal aging and that older adults have more variable characteristics than younger adults. Age-related changes in older talkersâ voices led to more negative evaluations of their voice quality compared to the quality of the voices of younger talkers. However, the voice properties of older talkers that were expected to decrease intelligibility in noise did not have the expected effect, possibly due to differences between talkers in articulation. Notably, when older talkers spoke in noise, they were able to increase intelligibility to a similar extent as younger talkers, regardless of their voice characteristics. In conclusion, healthy older talkers differ from younger talkers on a number of speech and voice characteristics that may lead to more negative evaluations of voice quality, but older talkers are similar to younger talkers in their ability to communicate in noisy situations.Ph.D