In September 2013, San Diego Chargers defensive back Paul Oliver committed suicide by shooting himself in his head in front of his wife and two kids. At only 29 years old, Oliver was among at least nine other active and retired football players who had killed themselves since 2010. All of them were diagnosed with chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease that can only be diagnosed after death. But that may soon change, as researchers might have figured out how to spot its hallmark signs through brain scans.

CTE develops through repeated traumatic brain injuries (TBIs) like concussions — both symptomatic and asymptomatic — which slowly destroy brain tissue. As this happens, proteins called tau also grow into tangles throughout parts of the brain, cutting off the brain's transport system for food and cell parts, and other materials. These problems combined lead to various others down the line, including memory loss, confusion, impaired judgement, impulse control problems, aggression, depression, and eventually dementia.

In a new study from researchers at the University of California, Los Angeles and Davis, as well as the University of Chicago, researchers have found a possible way to detect early signs of the condition using positron emission tomography (PET) scans. Fourteen former football players aged 40 to 86 with a history of repeated concussions underwent the scans after being injected with a substance meant to bind to the tau clumps and appear in a PET scan, The Associated Press reported.

All of the former players showed signs of tau buildup, with those experiencing the most severe symptoms also having deposits that covered a larger area. For example, The Los Angeles Times reports that those with clumps in only the brainstem and amygdala were less likely to have neuropsychiatric symptoms, while those with clumps extending into the medial temporal lobe, hippocampus, entorhinal cortex, and parahippocampal gyrus experienced worse symptoms — including cognitive impairment, anxiety, and depression.

Interestingly, the researchers also found that when they compared the scans to those of 28 healthy adults and 24 with Alzheimer’s, the football players had tau deposits in areas that differed from those in the Alzheimer’s patients — Alzheimer’s is another disease characterized by tau deposits. These patterns of tau, the researchers wrote, resembled those found in post-mortem samples of people with CTE.

The findings are already a step toward preventing the severe disease. If larger studies find these scans work, professional football players as well as boxers and other athletes who experience TBIs may have a way to detect the disease before symptoms start to appear (one of the football players, a former quarterback, hadn’t had any obvious symptoms). Such progress would not only help people prepare for what might develop but also help determine the effectiveness of treatments.

Source: Barrio J, Small G, Wong KP, et al. In vivo characterization of chronic traumatic encephalopathy using [F-18]FDDNP PET brain imaging. PNAS. 2015.