The Hidden Brain Damage in Boxers and Footballers

In 1928 a doctor described retired fighters with slurred speech, a tremor, fading memory and a change in temper. He called it punch-drunk. Families noticed the changes first. They still do.

He was describing a real disease almost a century before anybody could prove it. What changed recently is that we can see what causes it, and it is not only a boxing problem.

It follows hits, not knockouts

The damage does not track knockouts. It tracks the total number of hits to the head, including all the ones that seemed to do nothing.

Researchers call these subconcussive impacts. A clean jab. A header in training. A tackle where nobody went down. Each one moves the brain slightly inside the skull.

One of them does nothing you could measure. A career is tens of thousands, and nothing in sport was built to count them.

The signature in the brain

The brain is folded, and the tissue at the bottom of the folds takes the most strain when the brain moves. Small blood vessels anchor that tissue in place.

Think of a curtain pinned at one point and shaken. The pin is where it tears.

At those points a protein called tau starts to collect. In a healthy cell, tau is scaffolding. When damaged it comes loose, changes shape and clumps. The clumps sit around small vessels deep in the folds. No other disease leaves that pattern. The condition is known as chronic traumatic encephalopathy, or CTE.

The long gap

Players and fighters are usually fine through their careers and for years afterwards. Symptoms tend to start in the forties or fifties.

The damage is a process that was started. Tau appears to spread slowly from cell to cell. Somebody can stop at 30 and the process can continue without them.

The 90% figure

A brain bank examined 376 former NFL players and found the disease in 345. That is accurate, and it tells you almost nothing about a player's risk. The researchers said so themselves.

Those brains were donated, and families donate when they suspect something was wrong. It is like counting how many people in a waiting room are ill and concluding that most people are.

It proves the disease is common in that group. It does not tell you what fraction of all players develop it.

The stronger study

Researchers in Scotland traced former professional footballers and compared them with matched people from the general population. They looked at everybody, not at donated brains.

• The players died of neurodegenerative disease at about three and a half times the rate.
• They were less likely to die of heart disease and lung cancer, so this was a healthy group with one specific problem.
• Defenders, who head the ball most, had the highest risk.
• Goalkeepers, who rarely head it, were not raised at all.

Same sport, same training, different exposure.

Other sports, and not only sport

Linemen in American football rarely get concussed, but they collide on almost every play. Rugby shows a similar pattern. The disease has also been found in soldiers exposed to blasts and in people who suffered years of physical abuse.

This is about exposure, not about one game.

It cannot be diagnosed in life

There is currently no scan or blood test that confirms it in a living person. The only confirmation is examining brain tissue after death.

The symptoms are not specific. Memory trouble, mood change, irritability and poor planning are also caused by depression, sleep apnoea, alcohol and ordinary ageing. Most of those are treatable.

So the most likely explanation is usually one you can do something about. That is the practical reason to see a doctor and not a symptom list.

What sports have changed

• Heading removed from training for young children in several countries.
• Limits on contact sessions for professionals.
• Less sparring in gyms that used to do it daily.

None of this helps anybody already exposed. The only lever anybody has found is fewer hits.

What is still unknown

• What proportion of exposed people develop it.
• Why two people with the same career get different outcomes.
• Whether there is a safe threshold.
• Whether the process has started in any particular living person.

The short answer

It is real, and it follows total hits, not knockouts. If you played or fought and something has changed in your memory or your temper, see a doctor. Not because it is certainly this. Because it is probably something else, and most of the something elses can be treated.