Elderly people who have mild cognitive impairment and a history of serious concussion showed higher amounts of the protein deposits associated with Alzheimer's disease, according to a new study.

The results, published in the journal Neurology, suggest a potential link between a history of head trauma and later cognitive decline.

Researchers at the Mayo Clinic in Rochester, Minn., enlisted 589 elderly residents of surrounding Olmsted County beginning in 2004 and administered a battery of cognitive and memory tests, along with brain scans that show structure and metabolic function.

Tests showed 448 of the subjects, ages 70 to 89, had no memory or cognitive problems, and 141 had mild cognitive impairment. A roughly equal proportion of each group reported at least one concussion that involved memory loss, unconsciousness, or medical attention. The median age for the concussion was 21 for men and 32 for women.

Only the brains of those with cognitive impairment showed higher levels of amyloids, a kind of fibrous protein. Researchers suggested higher amyloid levels within the cognitively impaired group could be a response to a higher level of damage to the myelin coating of the axons of neurons - the brain's white matter.

Amyloid buildup has been associated with neurological disorders, particularly Alzheimer's disease. - L.A. Times