People who experience a traumatic brain injury and lose consciousness may be at higher risk for developing Parkinson’s disease later in life. However, researchers at the Icahn School of Medicine at Mount Sinai and the University of Washington School of Medicine were surprised to see no such link exists between TBI with loss of consciousness (LOC) and Alzheimer’s disease.
The findings published in JAMA Neurology go against a number of high-profile studies which have suggested TBI may contribute to future Alzhiemer’s disease.
The team involved with the latest study, the largest of its kind, analyzed data on head injuries from 7,130 older adults. Of those adults, 865 had experienced TBI with LOC before the study had begun and 142 of those were unconscious for more than one hour.
The goal was to see if TBI was associated with late-life clinical conditions such as dementia, Alzheimer’s disease, cognitive impairment, and Pariknson’s disease.
While the results of the findings found no association between TBI with loss of consciousness and dementia or Alzheimer’s disease, it did find a strong association between TBI with LOC greater than one hour and Parkinson’s disease.
Notably, after evaluating 1,652 autopsy findings from participatns, the team saw no evidence that TBI contributed to the formation of beta amyloid plaques or neurofibrillary tangles, the hallmark sign of Alzhimer’s disease in the brain.
Instead, the autopsies found an increased number of Lew bodies in those who had TBI with LOC for less than an hour and an increased risk of cerebral microinfarcts – which are related to strokes – in those with loss of conscioussness for over an hour.
“The results of this study suggest that some individuals with a history of TBI are at risk for late-life neurodegeneration but not Alzheimer’s disease,” said Kristen Dams-O’Connor, Ph.D., co-director of the Brain Injury Research Center and associate professor in the Department of Rehabilitative Medicine at the Icahn School of Medicine at Mount Sinai.
“We want to identify and treat post-TBI neurodegeneration while people are still alive, but to do this, we need to first understand the disease. Prospective TBI brain donation studies can help us characterize post-TBI neurodegeneration, identify risk factors, and develop effective treatments,” she said.
The findings lead the researchers to believe clinicians may be misdiagnosing those experiencing late-life neurodegeration from past TBIs as Alzheimer’s disease, which may be leading to ineffective treatment approaches.