Neurodegenerative changes after mild traumatic brain injury.

A link between mild traumatic brain injury (mTBI) and neurodegenerative diseases, specifically Alzheimer's disease and chronic traumatic encephalopathy (CTE), has long been suspected. Shared clinical symptomology - most notably the prominent role of central auditory dysfunction and sleep-wake disturbances in both disease states - and similar findings on postmortem pathological examination has further reinforced suspected commonality between these seemingly disparate entities. However, conventional imaging techniques, including computed tomography and anatomic magnetic resonance, are unable to detect the symptomatic injuries in mTBI patients and therefore detection of neurodegenerative changes in vivo has previously not been reported. Recent research using diffusion tensor imaging, a novel imaging technique, and focused on patient-reported symptoms has for the first time demonstrated imaging findings in mTBI patients in vivo that are strikingly similar to Alzheimer's dementia and CTE. Moving forward, research will focus on identifying what renders certain patients with mTBI susceptible to developing full-fledged Alzheimer's disease and CTE later in life.