NEFL and concussion: The clinical relevance of elevated CSF NFL without clinical symptoms or without cognitive impairment can be discussed, but earlier studies have shown that concussion increases the risk for additional concussions [51], that at least 12% of the athletes with fatal sport-related intracerebral bleeding have suffered from a concussion within 4 weeks prior to the injury [65] and that sport-related concussion is associated with long-term effects in form of chronic traumatic encephalopathy [60].