April 12, 2011

Multi-tasking Becomes More Difficult With Age

The neurological connections in older people's brains have a harder time switching between activities than younger adults, making multi-tasking more difficult with age, researchers found in a study.

Short-term memory, or "working" memory, is known by researchers to negatively affect both young and older adults. However, anecdotal accounts of "senior moments" "“ fleeting bouts of forgetfulness, especially in the midst of competing demands on attention "“ has a greater impact on older people, reports Reuters.

Working memory is defined by scientists as the capacity to hold and manipulate information in the mind for a period of time, and is considered a vital function to all mental operations. This includes one's ability to follow a conversion, as well as handle more complex tasks such as learning and reasoning.

The study measured brain activity during controlled multi-tasking experiments.

Forty volunteers were recruited by the University of California San Francisco. Half averaged in age at 25, and the other half were around 70 years old.

Their brains were scanned as they were asked to memorize a nature scene for 14 seconds. During which time, a face was randomly flashed up on the screen. Afterwards, each participant was asked to describe the face and then recall the nature scene.

The brain activity in the scans showed a switch in activity during the face image distraction for both groups, however, it was at a slower pace in the elderly brains.

"These results indicate that deficits in switching between functional brain networks underlie the impact of multitasking on working memory in older adults," says lead author Wesley C. Clapp, PhD, a postdoctoral fellow in the Gazzaley lab.

The Gazzaley lab, in a parallel study, broadened the perspective of what happens in the aging brain when the working memory is impacted with distractions. The key to memory formation is the ability to ignore irrelevant information. For example, when looking for an old friend in a crowded room, the ability for the brain to ignore the other faces, or the ability to enhance pertinent information such as the face of a new acquaintance met during the search for the old friend.

"The impact of distractions and interruptions reveals the fragility of working memory," says Professor Adam Gazzaley, a neurologist and co-author of the study.

"This is an important fact to consider, given that we increasingly live in a more demanding, high-interference environment, with a dramatic increase in the accessibility and variety of electronic media and the devices that deliver them, many of which are portable."

Gazzaley and his colleagues are exploring the potential of software brain-training programs to help older people improve their ability to mentally process tasks simultaneously.

The findings are reported in the online early edition of Proceedings of the National Academy of Sciences (week of April 11, 2011).


On the Net: