We’ve discussed concussion and head trauma more than once on this site (here, here and here for example). Gavet et al 2011 discuss the little understood nature of CTE, or the accumulation of concussive and sub-concussive forces upon a brain.
After a discussion of the gross and micro anatomical changes observed in ex-athletes who had CTE, the authors discuss diagnosis and profiles. Given that not all our readers are familiar with the various structures in the brain, if you are curious, you can read about it here. Average age of onset is 42.8. While this is generally a retired athlete, one should note that with an average life expectancy exceeding 82 in much of the western world, this individual has nearly half their life ahead of them and is already experiencing severe brain damage. American football players normally live 6 years with the disease while boxers manage a life with this condition for 20 years. Once it has run its course, full blown dementia will emerge. At this time, no diagnostic criteria exist for CTE. Generally, the patient complains of memory difficulties and mood changes or severe apathy with a history of head trauma. CTE increases the likelihood one will develop Alzheimer’s, Parkinson’s, ALS and other neurodegenerative diseases.
There is some evidence to support the idea that white matter integrity is changed with the onset of CTE and can be detected by diffusion tensor magnetic resonance imaging. Other markers that can change include glutamate/glutamine ratios and N-acetyl-aspartate. Genetically, the APOE gene appears to be either upregulated by the injury or those with it naturally upregulated are more likely to suffer from CTE. A CTE population investigated showed 57% with the gene while in the general populous it is at 28%. Again, this is correlational but it is a screening factor that can be easily checked.
Lastly, it is noted that the younger one has their first traumatic head injury, the more likely the more traumatic the CTE appears to be. While not conclusive this pattern is visible with the data currently available.
As we’ve mentioned previously, head injuries and concussions need to be taken seriously and athletes should not return to play before cleared. Further, as we can see from CTE, they need to be monitored throughout their careers and even early post-career in the event such neurological damage has taken place and begins to manifest before the behavior changes manifest with violent actions.