Regularly heading a soccer ball over a period of just two years could lead to a decline in memory and thinking skills, a new study has found.
Previous studies have suggested that the frequent impact can affect brain function and increase the risk of a specific type of dementia.
However, this research has focused on the effect on the brain at a single point in time without following participants over the years.
The new study examined brain changes in 148 amateur soccer players over two years using brain scans, as well as performance on memory and learning tasks.
Tests were taken twice – once at the beginning of the study and once two years later.
They found that not only was high-level heading associated with brain changes that indicate poorer memory, but it was also linked to a decline in task performance.
A number of soccer players have developed dementia and chronic traumatic encephalopathy, or CTE – a degenerative brain disease found in people with a history of repetitive brain trauma. Pictured: Bruce Murray goes for a header during a game
Several soccer players who headed the ball for years have since been diagnosed with chronic traumatic encephalopathy, or CTE – a brain condition linked to repetitive brain trauma that ultimately leads to dementia.
Symptoms include memory loss, confusion and impaired judgment.
‘There is enormous worldwide concern for brain injury in general and in the potential for soccer heading to cause long-term adverse brain effects,’ said senior author Dr Michael Lipton, professor of radiology at Columbia University.
‘A large part of this concern relates to the potential for changes in young adulthood to reduce risk for neurodegeneration and dementia later in life,’ he added.
Sir Bobby Charlton, regarded as one of England’s greatest-ever football players, was diagnosed with dementia in 2020
Bruce Murray, 57, the former forward for Team USA, is among the former athletes believed to suffer CTE – although the condition cannot be diagnosed until after death.
Murray recently revealed he’d been diagnosed with dementia – after forgetting to turn off his car’s ignition, checking himself into hotels for no reason and falling into a canal after losing his balance.
Jeff Astle, a UK player for Notts County and West Bromwich Albion, was the first British footballer to have an inquest rule that he was suffering from CTE.
Astle died in 2022, aged 59.
When heading the ball, the rapid movement of the skull produces friction between the brain and the bones in the head and stretches brain tissue.
Heading also drives inflammation in the brain, which can affect the tiny blood vessels that play a crucial role in protecting us from dementia and other degenerative brain conditions.
Soccer heading repeatedly is also thought to trigger the release of harmful proteins.
Researchers from Columbia University studied 148 young adult amateur soccer players, with an average age of 27.
Some 39 of the participants were female.
At the start and end of the study, researchers asked players to complete a questionnaire detailing how often they hit the ball with their heads.
The survey consisted of a series of questions about how often an individual plays, practices and heads the ball, and in what type of situations.
Two-year heading exposure was categorized as low, moderate or high.
The players were also assessed for their ability to memorize and recall lists of words.
They also underwent a type of MRI called diffusion tensor imaging (DTI) at the start of the study and then again two years later.
DTI captures the structure of the brain by tracking the microscopic movement of water molecules through the tissue.
Compared to their starting results, the high-heading group (who did over 1,500 headers in two years) had significant changes in frontal areas of the brain, which are involved with memory and learning.
Dr Lipton said: ‘Our analysis found that high levels of heading over the two-year period were associated with changes in brain microstructure similar to findings seen in mild traumatic brain injuries.
‘High levels of heading were also associated with a decline in verbal learning performance. This is the first study to show a change of brain structure over the long term related to head impacts in soccer.’
US Brandi Chastain (pictured right) and Canadian Charmaine Hooper (pictured left) head the ball 01 July 2000, during their semifinal match in the Women’s Gold Cup Tournament game in Louisville, Kentucky
Dr Lipton and his team conducted a follow-up study looking at the impact of repeated soccer heading on verbal learning performance.
They analyzed heading over 12 months and conducted DTI and verbal reasoning tests in 353 amateur soccer players aged between 18 and 53.
The brain has gray matter and white matter. Gray matter is where the processing of sensation, perception, voluntary movement, learning, speech and cognition takes place.
White matter provides communication between gray matter areas and between gray matter and the rest of the body.
The boundaries where the brain’s gray matter and white matter come together are known as the ‘gray matter-white matter interface.’
There is a sharp distinction between the two, which demonstrates a healthy brain.
There is also a significant difference in the density of brain material in this area, which makes it more vulnerable to injury.
Researchers found that the normally sharp gray matter-white matter interface was blunted in proportion to high repetitive head impact exposure.
Dr Lipton: ‘We used DTI to assess the sharpness of the transition from gray matter to white matter.
‘In various brain disorders, what is typically a sharp distinction between these two brain tissues becomes a more gradual, or fuzzier transition.’
Soccer is now the third most played high school sport for girls, with over 370,000 players worldwide.
