A study of Vietnam-era U.S. military veterans by Dr. Kristine Yaffe, a University of California professor and director of the Memory Disorders Clinic, revealed that individuals who had suffered any type of head injury or brain damage during their time in service had a higher likelihood of developing Alzheimer's disease or another form of dementia than did their peers who had not experienced mild or traumatic brain injuries. Over a 7-year monitoring period beginning in 1997, twice as many brain-injured veterans as non-brain injured people received dementia diagnoses.
Although all the veterans had been provided with protective headgear to help them survive explosions and other attacks, helmets can only provide limited protection to the brain. Protective head gear can minimize a concussion or head injury, but when experiencing a blow to the head the brain collides with the inside of the bony skull resulting in long-term effects that can be damaging. When the brain hits the sides of the skull, the brain tissues can be damaged, and nerves, blood vessels, and membranes can get torn. The damage is often at the microscopic level but has real functional effects.
While helmets and other protective headgear are protecting our heads, we may not realize the severity of the injury until many years later. The trauma caused in your brain after a blow to the head is far worse than one may expect. Although the skull may be unbroken, sometimes the brain strikes the side of the skull causing long-term effects, including dementia.