Scientists have found protein accumulations in the brain called beta amyloid plaques, a hallmark of Alzheimer's disease, were present at higher levels in people with memory problems who also had a history of trauma.

On average, plaque levels were 18 per cent higher in individuals who during their lives had suffered a concussion resulting in at least a momentary loss of consciousness.

Study leader Dr Michelle Mielke of the Mayo Clinic says their results add merit to the idea that concussion and Alzheimer's disease brain pathology may be related.

AAP