We still don't understand how TBI and Alzheimer's may be linked

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Traumatic Brain Injury (TBI) includes mild and serious concussions and represent brain damage. This brain damage can have short term, medium term and long term impacts to brain health and cognitive decline.

A recent research paper published in ScienceDirect examined 44 longitudinal studies to attempt to determine the relationship between cognitive decline and TBI. There is strong evidence that TBI particularly repeated TBI is closely tied to cognitive decline over time, however the precise relationship is not understood.

Of particular interest to the researchers were the following questions;

  • What is the course of the relationship between TBI and cognitive decline?
  • What is the time course of the relationship?
  • What factors influence the relationship (genetic, sex, age, injury related factors)?

The research was based on analysing the timing of assessments, injury severity, and the cognitive domains that were assessed in the 44 studies. The meta data showed that there were differences in the course of cognitive performance depending upon the injury severity and the cognitive qualities assessed.

The conclusions showed that there is not consistent influence of sex, genetics, or age on the outcomes. This would suggest that there isn’t a single pathway from TBI to Alzheimer’s but that the path is influenced by many different factors. More research is needed to determine how all the influences determine the outcomes.

The evidence is clear of the relationship as has been determined in many studies, and anecdotally it’s always been known that certain populations are susceptible to cognitive decline. Examples include phrases like ‘punch drunk’ or ‘shell shocked’. These were the historic terms used to describe the erratic behavior of people who were impacted by TBI.

Current thinking is that you should avoid concussion (TBI) particularly repeated concussion as there is certainly a strong link between long term cognitive decline and brain damage. The questions are how exactly does it happen and what influences the severity and onset of symptoms?

The leading causes of concussion include:

  • Car accidents
  • Workplace accidents
  • Sporting injuries
  • Assaults

Children and teens are more susceptible to concussion and TBI, as are women. It’s thought that younger brains are not fully developed, and musculature is weak leaving brains vulnerable to damage. Women too have weaker neck musculature which is though to play a part in their susceptibility to brain damage.