The present invention provides minimally invasive methods of detecting, diagnosing, and assessing neuronal damage associated with traumatic brain injury (TBI) or chronic traumatic encephalopathy (CTE). Specific species of microRNAs (miRNA), small, noncoding RNA molecules that play gene regulatory functions, are correlated with cellular damage and oxidative stress following TBI or CTE, allowing for rapid, minimally-invasive diagnosis and assessment of brain injury. The early identification and longitudinal assessment of neuronal damage in subjects suffering from or at risk of suffering from a TBI (e.g., football players, boxers, military personnel, fall victims) will improve clinical outcomes by guiding critical medical and behavioral decision making.
