Dementia after a head injury is a significant public health problem
If you or someone you’re with experiences an impact to the head and develops any symptoms of traumatic brain injury, seek medical advice even if symptoms seem mild. Call emergency services for anyone who is unconscious for more than a minute or two or who experiences seizures, repeated vomiting or symptoms that seem to worsen as time passes. Also seek emergency care for anyone whose head was injured during ejection from a vehicle, who was struck by a vehicle while on foot, or who fell from a height of more than 3 feet. Even if you don’t lose consciousness and your symptoms clear up quickly, a brain injury still may have occurred.
Younger people are more likely to have a head injury than older people. Head injury is the third most common cause of dementia, after infection and alcoholism in people younger than 50 years.
Over the past 30 years, research has linked moderate and severe traumatic brain injury to a greater risk of developing Alzheimer’s disease or another type of dementia years after the original head injury. Emerging evidence suggests that individuals who have experienced repeated traumatic brain injuries (concussions) or multiple blows to the head without loss of consciousness, such as professional athletes and combat veterans, are at higher risk of developing a brain condition called chronic traumatic encephalopathy (CTE) than individuals who have not experienced repeated brain injuries (CTE cannot be detected until after a person dies). Current research on how traumatic brain injury changes brain chemistry indicates a relationship between traumatic brain injury and hallmark protein abnormalities (beta-amyloid and tau) linked to Alzheimer’s. Some research suggests that traumatic brain injury may be more likely to cause dementia in individuals who have a variation of the gene for apolipoprotein E (APOE) called APOE-e4. More research is needed to understand the link between APOE-e4 and dementia risk in those who’ve had a brain injury.
Alzheimer’s disease and other dementias that may occur as a long-term result of traumatic brain injury are progressive disorders that worsen over time. As with all dementias, they affect quality of life, shorten lifespan and complicate the effort to manage other health conditions effectively.
Severe physical and mental trauma can cause acute dementia, known as delirium. Patients usually bounce back to their previous mental state. However, a person who is prone to dementia or already has Alzheimer’s may experience an acceleration of their mental decline.