Once the fallout from Deflategate dies down the NFL will have to again face the issue of head trauma in its players. On Friday another reminder of just how significant repeated blows to the head are to the long-term health of players came in a concerning report published by PBS’s Frontline.

The report, conducted by Boston University and Department of Veterans Affairs researchers and released on Friday, said that 87 of 91 former NFL players examined tested positive for chronic traumatic encephalopathy or CTE. The degenerative condition, which has been linked to early onset Alzheimer’s and dementia, is often considered a factor in the mental deterioration of former players.

“People think that we’re blowing this out of proportion, that this is a very rare disease and that we’re sensationalizing it,” Ann McKee, who runs a BU lab dedicated to the study of CTE, told Frontline. “My response is that where I sit, this is a very real disease. We have had no problem identifying it in hundreds of players.”

The biggest obstacle to being able to diagnose and study CTE is that the doctors need to examine players’ brains and the only way this can happen is for the player to be dead. Statistics might also be skewed because often the only relatives of deceased players willing to share their loved one’s brains are those who saw the player’s behavior grow erratic and were searching for an explanation.

CTE is going to gain increased attention with the release of a movie based on the life of Pittsburgh-area pathologist Bennet Omalu, who discovered the link between CTE and football players while examining the body of former Steelers center Mike Webster more than 10 years ago.

At the time, doctors focused on the effects of multiple concussions and suggested that numerous concussions were the direct cause of CTE. In recent years, the focus of their research has gone away from actual concussions and more to effects of constant head-against-head contact – something faced most by offensive and defensive linemen.

The NFL continues to say it is working to reduce head trauma and points to statistics that show a decrease in concussions of 35%, according to the Frontline report. Those figures don’t reflect the unreported concussions – those where a player feels woozy but refuses to tell the trainers – or the linemen who might not be concussed but are constantly smacking helmets against each other.