Scientists in the field of Alzheimer’s disease have, for many years, been searching for the triggers that might lead to development of Alzheimer’s disease. One area of extreme interest that has received significant media attention is the role of brain injuries in the development of cognitive disorders. While brain injuries are generally well established as causes for long-term decline in cognitive health, whether that injury might translate specifically to Alzheimer’s disease has been a subject of debate.
While animal data and some human studies have pointed to a likelihood that Alzheimer’s and concussions are indeed related, other studies of humans have not found similar correlations. The present study adds to the discussion by, for the first time, analyzing a large number of study participants with sophisticated imaging of the brain to identify the chemical and anatomical features of Alzheimer’s disease.
The study grouped participants into groups who were cognitively normal or mildly impaired at the time of the study. In each group, participants were age 70 years or older. The study reported that amongst people with mild cognitive impairment, those who had experienced head injuries showed more features suggestive of Alzheimer’s than those participants who had not experienced head traumas.
This finding supports the idea that head trauma resulting in momentary loss of consciousness or memory may be associated with risk of Alzheimer’s disease. However, the data from cognitively normal people who had experienced head traumas was more complicated. In this group, prior injury did not greatly increase features of Alzheimer’s disease. The scientists are still considering why this may have occurred. For now, the results support the idea that if a person is experiencing mild cognitive impairment, that impairment is more likely to be Alzheimer’s-related if there is also a history of head injury. In this case, head injuries had to be severe enough to cause momentary loss of consciousness or memory, but could have occurred many decades earlier, even into adolescence.
View the press release from the Mayo Clinic