Concussion and Alzheimer's disease again linked

Kathleen Blanchard's picture
Alzheimer's plaque in the brain linked to history of concussion

Understanding risk factors for Alzheimer's disease has become a major focus of research. The incidence of dementia is increasing and has raised concerns, especially given the aging population. Now researchers have again linked history of concussion to a buildup of Alzheimer's disease plaque in the brain,

The study

The investigation from researchers with Mayo Clinic in Rochester, Minn.found a "complex" link to concussion and dementia.

For the study, the researchers performed brain scans on 448 people without memory problems and 141 people with memory and thinking problems.

Among the 448 people tested,17 percent had no problems with cognition despite reporting a history of brain injury. But another 18 percent who had difficulty with memory also reported having a history of head trauma.

The study group who had memory problems combined with a history of having experienced a head injury had an 18 percent higher level of amyloid plaque in the brain compared to those who had not experience concussion.


What the finding means

Past studies have suggested brain trauma can cause tau protein to escape from brain cells where the contribute to the "clumps" of amyloid plaque found in the brain of people with Alzheimer's disease. Other studies have failed to find an association.

Studies have also suggested football players are at higher risk for Alzheimer's from traumatic brain injury (TBI).

Aging, genetic predisposition, history of depression, being male, nutrition and lifestyle factors have all been implicated in raising the risk of Alzheimer's disease but researchers are still uncertain what causes the disease.

"Interestingly, in people with a history of concussion, a difference in the amount of brain plaques was found only in those with memory and thinking problems, not in those who were cognitively normal," said study author Michelle Mielke, PhD, with Mayo Clinic in a press release. The finding is published Dec. 26, 2013 in the journal Neurology.

Mielke explains if concussion and amyloid plaque formation associated with Alzheimer's disease are linked, the relationship is complex. The small study does not mean head trauma from concussion definitely leads to Alzheimer's disease, but Mielke said the finding adds "...merit to the idea that concussion and Alzheimer's disease brain pathology may be related."

Image credit: Wikimedia Commons