Summary: Researchers report concussion can accelerate Alzheimer’s symptoms in people with a genetic risk for the disease.
Source: Boston University Medical Center.
Using MRI imaging, the thickness of their cerebral cortex was measured in seven regions that are the first to show atrophy in Alzheimer’s disease, as well as seven control regions. NeuroscienceNews.com image is for illustrative purposes only.
New research has found concussions accelerate Alzheimer’s disease-related brain atrophy and cognitive decline in people who are at genetic risk for the condition.
The findings, which appear in the journal Brain, show promise for detecting the influence of concussion on neurodegeneration.
Moderate-to-severe traumatic brain injury is one of the strongest environmental risk factors for developing neurodegenerative diseases such as late-onset Alzheimer’s disease, although it is unclear whether mild traumatic brain injury or concussion also increases this risk.
Researchers from Boston University School of Medicine (BUSM) studied 160 Iraq and Afghanistan war veterans, some who had suffered one or more concussions and some who had never had a concussion. Using MRI imaging, the thickness of their cerebral cortex was measured in seven regions that are the first to show atrophy in Alzheimer’s disease, as well as seven control regions.
“We found that having a concussion was associated with lower cortical thickness in brain regions that are the first to be affected in Alzheimer’s disease,” explained corresponding author Jasmeet Hayes, PhD, assistant professor of psychiatry at BUSM and research psychologist at the National Center for PTSD, VA Boston Healthcare System. “Our results suggest that when combined with genetic factors, concussions may be associated with accelerated cortical thickness and memory decline in Alzheimer’s disease relevant areas.”
Of particular note was that these brain abnormalities were found in a relatively young group, with the average age being 32 years old. “These findings show promise for detecting the influence of concussion on neurodegeneration early in one’s lifetime, thus it is important to document the occurrence and subsequent symptoms of a concussion, even if the person reports only having their “bell rung” and is able to shake it off fairly quickly, given that when combined with factors such as genetics, the concussion may produce negative long-term health consequences,” said Hayes.
he researchers hope that others can build upon these findings to find the precise concussion-related mechanisms that accelerate the onset of neurodegenerative diseases such as Alzheimer’s disease, chronic traumatic encephalopathy, Parkinson’s and others. “Treatments may then one day be developed to target those mechanisms and delay the onset of neurodegenerative pathology,” she added.
Funding: Funding for this study was provided by a VA SPiRe award I21RX001594, NIMH grant R21MH102834, and the Translational Research Center for TBI and Stress Disorders (TRACTS), a VA Rehabilitation Research and Development National Network Research Center (B9254-C).
Source: Gina DiGravio – Boston University Medical Center
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer’s disease” by Jasmeet P. Hayes, Mark W. Logue, Naomi Sadeh, Jeffrey M. Spielberg, Mieke Verfaellie, Scott M. Hayes, Andrew Reagan, David H. Salat, Erika J. Wolf, Regina E. McGlinchey, William P. Milberg, Annjanette Stone, Steven A. Schichman, andMark W. Miller in Brain. Published online January 11 2017 doi:10.1093/brain/aww344
Abstract
Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer’s disease
Moderate-to-severe traumatic brain injury is one of the strongest environmental risk factors for the development of neurodegenerative diseases such as late-onset Alzheimer’s disease, although it is unclear whether mild traumatic brain injury, or concussion, also confers risk. This study examined mild traumatic brain injury and genetic risk as predictors of reduced cortical thickness in brain regions previously associated with early Alzheimer’s disease, and their relationship with episodic memory. Participants were 160 Iraq and Afghanistan War veterans between the ages of 19 and 58, many of whom carried mild traumatic brain injury and post-traumatic stress disorder diagnoses. Whole-genome polygenic risk scores for the development of Alzheimer’s disease were calculated using summary statistics from the largest Alzheimer’s disease genome-wide association study to date. Results showed that mild traumatic brain injury moderated the relationship between genetic risk for Alzheimer’s disease and cortical thickness, such that individuals with mild traumatic brain injury and high genetic risk showed reduced cortical thickness in Alzheimer’s disease-vulnerable regions. Among males with mild traumatic brain injury, high genetic risk for Alzheimer’s disease was associated with cortical thinning as a function of time since injury. A moderated mediation analysis showed that mild traumatic brain injury and high genetic risk indirectly influenced episodic memory performance through cortical thickness, suggesting that cortical thinning in Alzheimer’s disease-vulnerable brain regions is a mechanism for reduced memory performance. Finally, analyses that examined the apolipoprotein E4 allele, post-traumatic stress disorder, and genetic risk for schizophrenia and depression confirmed the specificity of the Alzheimer’s disease polygenic risk finding. These results provide evidence that mild traumatic brain injury is associated with greater neurodegeneration and reduced memory performance in individuals at genetic risk for Alzheimer’s disease, with the caveat that the order of causal effects cannot be inferred from cross-sectional studies. These results underscore the importance of documenting head injuries even within the mild range as they may interact with genetic risk to produce negative long-term health consequences such as neurodegenerative disease.
“Mild traumatic brain injury is associated with reduced cortical thickness in those at risk for Alzheimer’s disease” by Jasmeet P. Hayes, Mark W. Logue, Naomi Sadeh, Jeffrey M. Spielberg, Mieke Verfaellie, Scott M. Hayes, Andrew Reagan, David H. Salat, Erika J. Wolf, Regina E. McGlinchey, William P. Milberg, Annjanette Stone, Steven A. Schichman, andMark W. Miller in Brain. Published online January 11 2017 doi:10.1093/brain/aww344
http://neurosciencenews.com/alzheimers-concussion-neurology-5925/
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