Dementia and Concussion

Dementia aware: what you need to know about concussion and the risk of developing dementia


What do football players, soccer players, ice hockey players and soldiers have in common? They are all at increased risk of experiencing repeated concussions, also called traumatic brain injury, and consequently, have an increased risk of developing dementia: early onset Alzheimer’s disease or chronic traumatic encephalopathy (CTE).


For decades, it was generally accepted that most boxers develop punch-drunk syndrome or boxer’s syndrome (dementia pugilistica) because of the number of blows to the head (concussions) they sustained in the ring. However, little thought was given to the long-term effect of concussions on other athletes until 2005 when a Neuropathologist, Dr. Omalu revealed that NFL players were at increased risk of developing CTE. Despite attempts to downplay the significance of Omalu’s research, in 2007, 2 significant events occurred:

  1. A post-mortem test was performed on the brain of Justin Strzelczyk, a 36-yr. old NFL player who had died 3 yrs. previously in a high-speed police chase. Analysis of his brain tissue revealed significant brain damage likened to severe dementia.
  2. 40 yr. old Canadian wrestler, Chris Benoit committed suicide after killing his wife and son. For years, he had experienced depression and anger problems. An autopsy found that his brain was so severely damaged that it was comparable to the brain of an 85yr old man with severe Alzheimer’s disease.

Both men had sustained multiple blows and hits to the head (concussions) throughout their professional careers; both men had chronic traumatic encephalopathy (CTE).


Unfortunately, CTE is not limited to professional contact sports, it can also affect anyone involved in any sport where a concussion can occur. The youngest person reported to have CTE is 17yr old Nathan Stiles who died after sustaining a concussion at his high school homecoming football game. Throughout high school he experienced multiple concussions, but as there was no post concussion protocol implemented at the school, he never took a sick day and continued to play, year after year, hit after hit, until that fateful day in October 2010. His autopsy revealed he had CTE.


What you need to know about concussion:

  • It can affect anyone, at any age, at any anytime, anywhere
  • It can knock a person unconscious, cause memory loss, nausea and vomiting, headaches, dizziness and ringing in the ears, it can also impair one’s ability to think and speak clearly
  • It occurs when a person experiences a blow to the head, or the head shifts too suddenly causing the brain to moves through the cerebral fluid (CSF) and hit the inside of the skull with force
  • Falls and motor vehicle accidents are the most common cause
  • It is rarely detected on x-rays or MRI
  • It often results in post-concussion syndrome: anxiety, headaches, dizziness, memory lapses, difficulty sleeping and concentrating and can last up to 6 mths
  • If a 2nd concussion occurs within minutes/days/weeks after initial concussion, second impact syndrome occurs where the brain and its arteries swell dangerously resulting in death


Concussion is graded level 1 mild, 2 moderate and 3 severe:

  • Grade 1 mild: temporary disorientation, blurred vision, possible nausea and vomiting without unconsciousness. Symptoms disappear within 15mins to 30mins. Medical attention is not usually required, unless symptoms worsen. If you have sustained multiple grade 1 concussions, medical assessment is recommended
  • Grade 2 moderate: as above, except symptoms can last from 30mins to 24 hrs. 24-hour observation in hospital/home is recommended
  • Grade 3 severe: The classic concussion. It is the most serious with loss of consciousness lasting mere seconds to 5 minutes. Immediate medical attention is required


How to reduce your risk of concussion:

  • Wear a seatbelt
  • Wear a helmet when skiing, cycling, skateboarding
  • Ensure environment is well lit and free of tripping/slipping hazards
  • Wear correct footwear
  • If playing a contact sport, wear protective headgear/equipment and follow designated concussion protocol


Besides all the obvious dangers of concussions, increasing evidence shows that repeated concussions can lead to early onset dementia. With 3 or more concussions, the risk of early onset Alzheimer’s disease or CTE increases 5-fold.

Chronic traumatic encephalopathy (CTE) is a progressive degenerative disease of the brain usually caused by a history of repetitive brain trauma e.g. concussions. Trauma to the brain can cause a build up of an abnormal protein called tau which slowly kills healthy brain cells, the neurons (see 5 common dementias). The most common signs of CTE are mood and behavioural changes, memory loss, slurred speech, parkinsonism and gait impairment, and impairment of executive dysfunction (planning, thinking, behaviour control) (


Effects of concussion on the person with dementia:

People with dementia are at increased risk of falling and/or hitting their head which frequently result in concussion and an increased risk of developing a brain bleed (subdural hematoma). Of note, people with dementia who are taking anticoagulants (warfarin) are at increased risk of a brain bleed after sustaining any blow to the head. A subdural hematoma occurs when blood vessels burst in the space between the brain and the dura mater, the outer layer that covers the brain. The bleeding forms a hematoma which put pressure on the brain tissue and the person with dementia may experience:

  • Headache
  • Vomiting
  • Drowsiness and dizziness
  • Increased confusion
  • Increased blood pressure
  • Weakness on one side of body
  • Unequal pupils
  • Slurred speech
  • Seizure
  • Unconsciousness


There is no evidence that a single concussion increases risk of dementia and similarly, not everyone with a history of repeated concussions will develop early onset Alzheimer’s or CTE. However, the more injuries to the head one experiences, the more susceptible that person is to develop some form of dementia. Therefore, promoting and ensuring safe brain health should be high on everyone’s list: young and old.

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