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By The Canadian Press

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Reading the newspaper? Trying to balance the bank book? It might be best to turn off the TV.

Toronto scientists have found further evidence that older adults have a hard time tuning out distractions when trying to concentrate on a single task.

The new research, published in this week's The Journal of Neuroscience, suggests older brains are less able to filter irrelevant information from the environment than the brains of younger adults.

This seems to make it more difficult for older adults to focus on the task at hand, said lead author Dale Stevens, who conducted the research at the Rotman Research Institute at Baycrest as a doctoral student at the University of Toronto.

It is known from behavioural studies that older adults are more easily distracted, but this is the first to look at what is going on in the brain when people try to form a memory and fail, said Stevens.

"This certainly is consistent with the way we understand the problems older people might encounter when encoding information in everyday life," said Michael Rugg, director of the Center for the Neurobiology of Learning and Memory at the University of California, Irvine.

Stevens and his colleagues used functional magnetic resonance imaging (fMRI) to scan the brains of 12 younger adults and 12 older adults.

The groups were shown pictures of faces and were later asked whether they recognized any.

When both groups failed to recognize a face, the researchers saw decreased activity in the memory-encoding regions of the brain, including the hippocampus, something the researchers expected.

But when older adults looked at faces they later forgot, their brains showed increased activity in a region that should have been quiet during memory encoding - the auditory cortex, the part of the brain that processes sound in the environment. The group of older adults had an average age of 70.

"This indicates that older adults were not able to suppress or filter out the noise of the fMRI machine," said Stevens.

"We did not see this in the younger adults at all."

As it scans, an fMRI machine makes loud, repeated knocking noises.

Rugg said the study suggests auditory distractions may prevent older people from properly filing memories.