When representing victims of traumatic brain damage, I typically ask the treating physicians whether, to a reasonable degree of medical probability, he or she can say that, as a result of the head injury, the victim is at an increased risk of developing dementia later in life. The answer I often heard was the link between a traumatic brain injury and increased risk of dementia was not well-settled in the literature.
I read a blog about a prospective study of brain injured Vietnam combat veterans which cited an interesting article in the journal, Brain. The study by Raymont, et al. looked into the possibility of cognitive decline (as opposed to dementia) many years following a head injury, and found evidence that patients with penetrating head injury, compared with matched controls, demonstrated significantly exacerbated decline in general intelligence. This study is consistent with earlier studies which supported the concept of exacerbated decline after traumatic brain injury.
These findings are significant as traumatic brain injury is the primary cause In the U.S. of death and disability in those under 35 years of age. Each year approximately 55,000 deaths are caused by a traumatic brain injury and an additional 50,000 people suffer from TBI-related cognitive, behavioral, and social deficits. Raymont, et al. (citing Kraus and McArthur, 1996). As the New York Times has reported, traumatic brain injury is the signature injury of the Iraq war, with nearly two-thirds of injured U.S. soldiers sent from Iraq to Walter Reed Army Medical Center having been diagnosed with traumatic brain injuries. Unfortunately, the news coverage of this tragedy also reveals that Walter Reed and the entire VA system are under-diagnosing brain injuries in returning soldiers, so the numbers are likely much higher. Moreover, the quality of care the soldiers are receiving is atrocious. The bottom line is that these returning soldiers face a lifetime of problems, including accelerated decline in general intelligence in later years.