Older Adults' Speech-Processing Difficulties May Stem From 'Fast, Noisy Talk,' Not Deafness

Tun’s findings appeared in a recent issue of Psychology and Aging.

Understanding spoken language ranks among the most complex tasks we call upon our brains to handle and, all things considered, older adults do a remarkable job of keeping up," says Tun, an adjunct assistant professor of psychology at Brandeis' Volen National Center for Complex Systems. "Yet despite essentially perfect hearing, the older subjects in our study still couldn’t match the language-processing abilities of younger people in settings that were noisy or where speech was exceptionally fast."

Most tests of language comprehension take place in the insulated silence of a speech lab; like these studies, Tun's found no difference in undergraduates' and older adults' ability to decipher speech in quiet surroundings. But Tun's study also superimposed the din of 20 chattering voices over the headphone-fed passages test subjects were trying to decipher. Seniors’ ability to process speech dropped off more rapidly than their younger counterparts' when the speech was played over this "multi-person babble."

"We live in a very noisy society, and this is particularly detrimental to older residents, who have trouble overcoming all that background noise to get the information they need," Tun says.

The seniors in Tun’s study, with an average age of 71, were also more likely to be stymied by words pouring forth at rates much faster than 140 to 180 words per minute, the pace of a typical conversation. Particularly difficult for older adults, Tun suggests, may be rapid-fire advertisements, harried physicians rattling off information about medications, and warp-speed news anchors and weathercasters, who can reach speeds of 300 words per minute.

Tun says her work suggests that instead of talking to older adults in a very loud and unnaturally sing-song voice -- a common response to the widespread but erroneous belief that most seniors are hard of hearing -- a more worthwhile approach might be to keep speedy speech in check while minimizing distracting background noise from televisions or radios, ringing telephones, and other people's conversations.

This susceptibility to fast talkers and background noise doesn't just spring up when people hit age 65, Tun says: In fact, it's in step with current theories that some cognitive abilities gradually taper off over the course of a lifetime. By the time people reach their 60s or 70s, it's estimated that many mental abilities -- not just speech-processing skills -- are functioning 30 to 50 percent more slowly than they were at a younger age.

Tun's work is supported by the National Institute on Aging and the W.M. Keck Foundation.