The Link Between Alzheimer’s Disease and Traumatic Brain Injuries

Alzheimer's Disease (AD), a neurological disorder that impairs a person’s cognitive abilities, is expected to impact 13.8 million Americans by 2060. Causes of AD are unknown, however, factors that can lead to AD include a combination of aging, genetic propensities, environmental and lifestyle factors. Additionally, studies have shown that adults with a history of a moderate traumatic brain injury (TBI) had a 2.3 times greater risk of developing AD and those with a history of a severe TBI had a 4.5 times greater risk. The enhanced risk is driven by the empirical evidence that changes in neural tissue due to TBIs exhibit similar aberrations to AD. Both TBIs and AD share similar pathological abnormalities such as accumulation of amyloid plaques and tau proteins, cell membrane damage, and organelle dysfunction. The purpose of this review is to 1) explore the cerebral and physiological link between TBIs and AD, 2) discuss studies that examine this link by isolating different factors that lead to the accumulation of Aβ/tau deposition leading to AD-like pathology, and 3) discuss current treatments currently used to slow the progression of Alzheimer's. While research has established an association between TBIs and an increased risk of developing AD, a conclusive link has yet to be established. The challenge is distinguishing between the neurodegenerative impact of a TBI and the natural pathological changes due to genetic factors and other risk factors of AD. Additional research is necessary to build upon evidence from past studies to determine a causal link between TBIs and AD.