Growing public health concern exists over the incidence of chronic traumatic brain injury (TBI) in athletes participating in contact sports. Chronic TBI represents a spectrum of disorders associated with long-term consequences of single or repetitive TBI and includes chronic traumatic encephalopathy (CTE), chronic postconcussion syndrome, and chronic neurocognitive impairment. Neurologists should be familiar with the different types of chronic TBI and their diagnostic criteria.
CTE is the most severe chronic TBI and represents the neurologic consequences of repetitive mild TBI. It is particularly noted among boxers and football players. CTE presents with behavioral, cognitive, and motor symptoms, and can only be definitively diagnosed postmortem. Chronic postconcussion syndrome is defined as postconcussion symptoms that last longer than 1 year and do not appear to resolve; it may develop after a single concussive event. Chronic neurocognitive impairment is an all-encompassing clinical term denoting long-term neurologic sequelae secondary to sports-related trauma and can present either within the postconcussion syndrome or years after a symptom-free interval.
This article discusses the diagnostic evaluation of chronic TBI, including clinical history, neurologic examination, neuropsychological testing, neuroimaging, and laboratory testing, as well as the distinctions between CTE, chronic postconcussion syndrome, and chronic neurocognitive impairment. Neurologic impairment among athletes exposed to repetitive brain injury appears to be a real phenomenon. Because CTE has no established treatment, prevention is of paramount importance for athletes participating in contact sports.