Mental activities can preserve structural integrity in the brains of older people

Updated on: Monday, November 26, 2012

Mental activities like reading and writing or even playing games like chess can preserve structural integrity in the brains of older people, according to a new study.

Researchers from the Rush University Medical Center and the Illinois Institute of Technology in Chicago studied the effect late-life cognitive activity might have on the brain's white matter, which is composed of nerve fibres, or axons, that transmit information throughout the brain.

"Reading the newspaper, writing letters, visiting a library, attending a play or playing games, such as chess or checkers, are all simple activities that can contribute to a healthier brain," lead researcher Dr Konstantinos Arfanakis said.

The researchers used a magnetic resonance imaging (MRI) method known as diffusion tensor imaging (DTI) to generate data on diffusion anisotropy, a measure of how water molecules move through the brain.

In white matter, diffusion anisotropy exploits the fact that water moves more easily in a direction parallel to the brain's axons, and less easily perpendicular to the axons, because it is impeded by structures such as axonal membranes and myelin.

"This difference in the diffusion rates along different directions increases diffusion anisotropy values. Diffusion anisotropy is higher when more diffusion is happening in one direction compared to others," Arfanakis said in a statement.

The anisotropy values in white matter drop, however, with ageing, injury and disease. "In healthy white matter tissue, water can't move as much in directions perpendicular to the nerve fibres," Arfanakis said.

"But if, for example, you have lower neuronal density or less myelin, then the water has more freedom to move perpendicular to the fibres, so you would have reduced diffusion anisotropy. Lower diffusion anisotropy values are consistent with ageing," Arfanakis added.

The study included 152 elderly participants, mean age 81 years, from the Rush Memory and Aging Project, a large-scale study looking at risk factors for Alzheimer's disease.

Participants were without dementia or mild cognitive impairment, based on a detailed clinical evaluation. Researchers asked the participants to rate on a scale of 1 to 5 the frequency with which they participated in a list of mentally engaging activities during the last year.

Among the activities were reading newspapers and magazines, writing letters and playing cards and board games. Data analysis revealed significant associations between the frequency of cognitive activity in later life and higher diffusion anisotropy values in the brain.

"Several areas throughout the brain, including regions quite important to cognition, showed higher microstructural integrity with more frequent cognitive activity in late life," said Arfanakis. The study was presented at the annual meeting of the Radiological Society of North America.

Mental activities can preserve structural integrity in the brains of older people

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