Chapter 10 - Long-term sequelae of mild-repetitive and severe traumatic brain injury: Clinical manifestations, neuropathology and diagnosis by tau PET imaging

Abstract

Long-lasting neuropsychiatric sequelae of traumatic brain injury (TBI) can be devastating. Recent clinical and neuropathological studies have brought a growing awareness of the epidemiological association between TBI and neurodegenerative diseases later in life. Chronic traumatic encephalopathy (CTE), formerly known as boxer’s encephalopathy is now a widely recognized neurodegenerative disease associated with mild-repetitive TBI. CTE is characterized by the deposition of hyperphosphorylated tau (p-tau) protein as neurofibrillary tangles around small blood vessels of the cortex, typically at the sulcal depths. Late-onset neuropsychiatric sequelae are also common in the chronic stage of severe TBI. Several epidemiological studies have also shown that severe TBI is one of major risk factors of Alzheimer’s disease and other neurodegenerative diseases. Deposition of neurofibrillary tangles similar to CTE was found in the post-mortem brains of severe TBI. Overlapping long-term outcomes between mild-repetitive and severe TBI indicate that tau pathology can be regarded as a pervasive condition of TBI.