People with traumatic brain injuries may have buildup of plaques related to Alzheimer's disease

A new study suggests that people with brain injuries following head trauma may have buildup of the plaques related to Alzheimer's disease in their brains. The research is published in the February 3, 2016, online issue of Neurology®, the medical journal of the American Academy of Neurology.

A corresponding editorial states that over the past decade the rate of emergency department visits related to traumatic brain injury (TBI) has increased by 70 percent. The editorial also says an estimated three to five million Americans live with a TBI-related disability.

"The study is small and the findings preliminary, however, we did find an increased buildup of amyloid plaques in people who had previously sustained a traumatic brain injury," said study author Professor David Sharp, MD, of Imperial College London, in the United Kingdom. "The areas of the brain affected by plaques overlapped those areas affected in Alzheimer's disease, but other areas were involved. People after a head injury are more likely to develop dementia, but it isn't clear why. Our findings suggest TBI leads to the development of the plaques which are a well-known feature of Alzheimer's disease."

For the study, nine people with an average age of 44 who had a single moderate to severe TBI had PET and MRI brain scans. The brain injuries occurred between 11 months and up to 17 years before the start of the study. The participants were compared to 10 people with Alzheimer's disease and nine healthy participants.

The PET scans used a marker that detects plaques in the brain. The MRI scans used diffusion tensor imaging to detect damage to brain cells that occurs after TBI. Both the people with brain injuries and the people with Alzheimer's disease had plaques in the posterior cingulate cortex, which is affected early in Alzheimer's, but only those with brain injuries had plaques in the cerebellum. The researchers also found that plaques were increased in patients with more damage to the brain's white matter.

"It suggests that plaques are triggered by a different mechanism after a traumatic brain injury," Sharp said. "The damage to the brain's white matter at the time of the injury may act as a trigger for plaque production."

"If a link between brain injury and later Alzheimer's disease is confirmed in larger studies, neurologists may be able to find prevention and treatment strategies to stave off the disease earlier," said Sharp.