Older adults may have difficulty processing subtle differences in the timing of what they see and hear, according to new Canadian research. A study from Ontario's University of Waterloo found that older people have a harder time when accurately processing the order of events than those who are younger — and it could point to solutions for impaired rapid decision-making during important tasks such as driving.
Researchers presented participants of various ages with pairings of a light and a sound — either simultaneously or with a delay — and found that both young and older adults could determine with similar accuracy whether they occurred at the same time. But when a delay was introduced between the light and the sound, older adults performed much worse.
"To make sense of the world around us, the brain has to rapidly decide whether to combine different sources of information," says the paper's author, Michael Barnett-Cowan of the university's Department of Kinesiology. "Older adults often experience problems processing multisensory information, which in turn can affect everyday tasks from following conversations, to driving, to maintaining balance."
In another test, researchers showed the study participants two lights travelling toward one another. On most occasions, the lights appeared to pass easily by but, when a sound occurred as the lights touched, the two seemed to bounce off each other. Here, older adults still perceived the lights as colliding even when the sound occurred well before or after the lights touched. This, the researchers say, suggests that older adults combine fragments of sensory information that do not belong together.
The study — which appears in the journal Experimental Brain Research — is the first to compare the ways in which younger and older people process and combine sensory information about time. The researchers say their findings could help understanding of this mental mechanism and so reduce impairments in distinguishing the order of events.
Seniors are the fastest growing segment of the driving population and, according to the National Blueprint for Injury Prevention in Older Drivers, driving-related deaths are the leading cause of accidental deaths for Canadians aged 65 to 75, while the number of older drivers in Canada is expected to double by 2040. Barnett-Cowan says the tests that made up this study could potentially be used as part of the driver examinations for older people.
Possible solutions for improving altered perceptions of time in older adults could come from training with video games or other such brain stimulation. "Health professionals are able to address many changes in our vision and hearing as we age using corrective lenses and hearing aids, for example," says Barnett-Cowen. "But these interventions don't help with changes in the brain's ability to combine sensory information. If we can identify and address impaired timing of events in the elderly, we could potentially improve the quality of life, safety and independence for many older people."