Do high school football players show neurophysiological changes after head impacts?
Research shows that high school football players experience changes in brain function after exposure to head impacts during a season. These changes can happen even without a formal concussion diagnosis. Studies using advanced brain imaging and sensors found that repeated hits to the head alter brain activity and chemical levels over time.
What the research says
One study tracked 91 high school football players over up to four seasons using helmet sensors and brain imaging. It found that head impact exposure was linked to changes in brain activity patterns, regardless of whether a player suffered a concussion. The study measured both rhythmic and irregular brain signals before and after the season to see how impacts affected them 1.
Another study used magnetic resonance spectroscopy to look at brain chemicals in 55 high school football players. It found that linemen showed different chemical changes in the brain compared to non-linemen. These chemical shifts were linked to the number of head impacts they received during the season. The changes were seen even in players who did not report symptoms 6.
A third study followed players for two seasons and used sensors to count every head hit. It found that a large group of players who never had a diagnosed concussion still showed significant changes in brain function. The amount of change was related to how many hits the player took. This supports the idea that repeated sub-concussive hits build up effects over time 7.
A fourth study looked at young men aged 15 to 19 and found a third group of players who had no symptoms but still showed measurable changes in brain function and memory. This group had taken many hits but did not meet the criteria for a clinical concussion diagnosis. Their brain scans and memory tests showed clear differences from players with no hits at all 5.
What to ask your doctor
- How can we track head impacts in my child to understand their exposure?
- What brain changes might occur even if there are no symptoms after a hit?
- Are there different risks for linemen compared to other positions?
- When should we retest brain function after a season of play?
- What signs suggest hidden brain changes before a concussion is diagnosed?
This question is drawn from common patient questions about Neurology and answered using cited medical research. We do not provide individualized advice.