The dark spots indicate the presence of tau proteins. Photo: Ann C McKee, M.D./VA Boston/Boston University School of Medicine

Getting injured on the field is just part of the job description for professional athletes playing full-contact sports. Joints get pulled, ACLs get torn and skulls get rattled. But it turns out that even if you don’t sustain a concussion, you can still be left with a major brain injury.

There’s no treatment for chronic traumatic encephalopathy (CTE), which is the cumulative damage of the pathways in the brain caused by blows to the head – major and minor – over time. The rattling causes proteins known as tau proteins to build up, putting the skids on neural impulses. As those pathways slow down, the person may experience memory loss, aggression and depression. There’s no way to diagnose CTE in a live person.

Scientists wanted to find out just how prevalent this disease is, but they had to consult dead athletes who donated their bodies to research. Researchers at the Center for the Study of Traumatic Encephalopathy at Boston University examined the brains of 18 professional athletes who played contact sports, and 17 of them had CTE.

The debate goes on in the NFL about how to combat brain injury, but one partial solution may be in the equipment. Standard NFL helmets are extremely hard to protect against a lot of force. Unfortunately, that hardness can cause injury too, with nothing soft to cushion the blow through the helmet. Now companies are working on cushioning that responds to the nature of the hit, staying rigid when a big blow is sustained, and softening up for those minor hits.