However, the key phrase “increase risk for” means that TBIs do not cause dementia but do increase the likelihood of having dementia sometime in the future.
In a recent and extensive review of the research literature, Sharan Shively, MD, Ph.D., and colleagues report that a history of moderate and severe TBIs increases the risk of having late-life dementia 2 - to - 4 times that of people who have never experienced a traumatic brain injury. (Note 2) To come to this conclusion, Shively and colleagues reference earlier studies that compare the presence or absence of later-in-life dementia in people who suffered concussions of sufficient severity to cause loss of consciousness to individuals who report never having experienced that degree of head trauma. (Note 2) People who experience multiple traumatic brain injuries are at high risk of developing dementia later in life. (Note 1)
The syndrome, associated with having multiple traumatic brain injuries was originally described in 1928. Called dementia pugilistica or “punch drunk” was first observed in boxers who suffered repeated knock-outs. (Note 3) It took many more years of casual observation before medical researchers linked a history of repeated sports and military-related head injuries, to the onset of dementia symptoms later in life. The condition, chronic traumatic encephalopathy, (CTE) now receives considerable coverage in the public media.
Signs and symptoms of CTE usually begin eight to 10 years after the traumatic brain injuries and include difficulty in thinking, impulsive behavior, memory loss, substance abuse, as well as suicidal thoughts or behavior. (Note 4) Over time, the changes caused by CTE worsen as well as progress to aggressive behaviors, tremor, and speech and language difficulties. (Note 4) More than one-third of people with CTE eventually show signs of other degenerative brain diseases such as dementia and Parkinson disease. (Note 3)
Undoubtedly, ongoing and future research will improve our understanding of traumatic brain injuries and their relationship to later-in-life dementia. In the meantime, you can reduce the likelihood of receiving a head injury by trip-proofing your home, being observant of hazards such as low tree branches and open kitchen cabinet doors, as well as by wearing a helmet to prevent sports-related injuries.
Even if you have experienced multiple head injuries, you may be able to reduce your overall risk of developing dementia by implementing lifestyle changes that include such things as maintaining a healthy weight, eating a heart-healthy diet, as well as participation in an assortment of physical, social and mental activities.
1. Alzheimer’s: Can a head injury increase my risk?”, http://www.mayoclinic.org/alzheimers-disease/expert-answers/faq-20057837 (accessed March 21, 2016)
2. Shively et al, “Dementia Resulting from Traumatic Brain Injury” https://www.researchgate.net/publication/229011632_Dementia_Resulting_From_Traumatic_Brain_Injury_What_Is_the_Pathology (accessed March 22, 2016)
3. What Is Chronic Traumatic Encephalopathy?, http://www.brainline.org/content/2010/12/what-is-chronic-traumatic-encephalopathy.html (accessed April 7, 2016)
4. Chronic Traumatic Encephalopathy, http://www.mayoclinic.org/diseases-conditions/chronic-traumatic-encephalopathy/basics/definition/con-20113581 (accessed April 6, 2016)
Contributor: Janet Yagoda Shagam, Ph.D., is a freelance medical and science writer and the author of “An Unintended Journey: A Caregiver's Guide to Dementia.” Available through Amazon.
The opinions expressed by contributing authors are not necessarily the opinions of the Dementia Society, Inc. We do not endorse or guarantee products, comments, suggestions, links, or other forms of the content contained within blog posts that have been provided to us with permission, or otherwise. Dementia Society does not provide medical advice. Please consult your doctor. www.DementiaSociety.org