Aug 5th 2019 marks a big day for research in football and head trauma.
A team of doctors published their results of a first of a kind study where they were able to find a link between dementia and structural deficits in the brain causing CTE (Chronic Traumatic Encephalopathy )
The study reveals the biological mechanisms that link years of playing football to white matter injury, atherosclerosis and other mechanisms which may contribute to dementia in patients with CTE.
It was published on August 5th in JAMA neurology.
The lead researcher for this study Michael Alosco, is a BU school of medicine assistant professor of neurology and co-director of the clinical course at BU’s Alzheimer’s Disease Center and CTE center.
The objective of the study was:
- To investigate the association of white matter rarefaction and cerebrovascular disease with dementia in deceased men older than 40 years who played football and had CTE.
- To actually prove that the dementia seen in CTE patients was truly caused by years of playing football.
A total of 180 men’s brains older than 40 years of age were included in the study. Mean age of sample at death was 67.9
Design and Setting: This is a cross-sectional study
It involves analyses of data from the ongoing Understanding Neurologic Injury and Traumatic Encephalopathy (UNITE) Study, which included brain donors from the Veterans Affairs–Boston University–Concussion Legacy Foundation brain bank between 2008 and 2017.
Outcome and Measures:
The primary outcome of the study was to understand the extent of white matter diminution. Other outcomes that were measured included,
- Atherosclerosis severity
- Number of infarcts, microinfarcts and microbleeds
- Extent of accumulation of phosphorylated tau, a protein that is often elevated in patients with CTE
- Moderate to severe white matter diminution was a common finding across all samples as well as atherosclerosis.
- Infarcts, microinfarcts and microbleeds were fewer common findings.
- Also, more years of play was associated with more white matter rarefaction
- And more years of play was associated with more tau protein accumulation
- The above three were independently associated with dementia.
- Amongst older players that played football and had CTE, more years of football play was associated with more white matter reduction in their brain and greater accumulation of tau protein.
- Atherosclerosis was also noticed in these brain samples as being moderate or severe.
- There neuropathological changes showed a direct correlation with dementia in CTE.
- The pathological changes leading to dementia could have resulted from repeated trauma to the head resulting in diminution of white matter or from non-traumatic pathologies such as atherosclerosis.
Well it is a known fact that traumatic brain injury can cause damage to our brains white matter as well as gray matter.
White matter is responsible for the connections between the brain’s neurons. These connections help us function normally on a day to day basis. A disruption in these connections can lead to cognitive disability, behavioral disability, poor social emotional skills etc. These are seen in patients with dementia.
Now before we proceed, lets also understand what CTE is.
In simple terms, it is brain degeneration secondary to repeated blows / trauma to the head.
Pathologically, CTE is characterized by an abnormal buildup of a protein named p-tau in the brain. The buildup of this protein is responsible for abnormal signals and is associated with dementia.
The other interesting finding was that white matter diminution was more severe as the age progressed. Hence severity of dementia had a direct correlation with how much football you played and how many concussions you suffered.
This study binds a lot of factors together and provides a solid link between head impacts, CTE, dementia, p-tau levels, atherosclerosis and white matter changes.
However, it would be great if a longitudinal study could be conducted on living people and their symptoms identified and study over a span of years to better improve the accuracy of the data collected.
The biggest limitation of the study was its inability to distinguish what contributed more towards the dementia, was it the p-tau levels or the white matter changes.
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