The brain damage comes before the disease shows up
Decades of collisions on the football field leave more than memories — they leave measurable traces in the architecture of the brain itself. A new MRI study of 169 former players has found that the grooves folding the brain's surface grow shallower in proportion to the cumulative blows a player absorbed over a career, particularly in regions long associated with chronic traumatic encephalopathy. The findings do not yet constitute a diagnosis, but they open a quiet and consequential question: whether the shape of a living brain might one day reveal the shadow of a disease that has, until now, only been confirmed in the dead.
- Repeated head impacts are physically reshaping former football players' brains, with key sulci — the grooves between cortical ridges — measurably shallower the more cumulative trauma a player endured.
- CTE, the progressive neurodegenerative disease linked to contact sports, has never been diagnosable in living patients — a gap that leaves thousands of former athletes without answers and without early intervention.
- The sulcal changes detected by MRI do not yet align with clinical symptoms, tau PET imaging, or neuropsychological test results, suggesting the brain's structure may be deteriorating silently before disease fully declares itself.
- Researchers are working to determine whether sulcal morphology can be validated as a reliable early-warning biomarker — a tool that could one day identify high-risk individuals before irreversible neurodegeneration takes hold.
- The study's own limits remind us how much remains unknown: not every player exposed to repetitive impacts develops CTE, and structural change alone cannot yet predict who will.
An MRI study published in Brain Communications has found that the brain's folded grooves — the sulci — grow measurably shallower in former football players in direct proportion to the cumulative head impacts they sustained during their careers. Examining 169 former players with an average age of 57 and comparing them to 54 non-players of similar age, researchers identified the left superior frontal sulcus as particularly affected, a region already known for its vulnerability to chronic traumatic encephalopathy.
CTE develops when the protein tau accumulates abnormally in the brain's sulcal depths, triggering the slow shrinkage of surrounding cortical tissue — widening and flattening the grooves over time. The disease has been documented in football players, boxers, and other contact sport athletes for years, but a definitive diagnosis has remained possible only through post-mortem autopsy. The new findings raise the possibility that sulcal shape, measured through a specialized scale called CalcSulc, could serve as an earlier and more sensitive structural signal than conventional measures like cortical thickness or brain volume.
Yet the study also surfaces a critical limitation. The sulcal changes bore no relationship to clinical diagnoses of Traumatic Encephalopathy Syndrome, to neuropsychological performance, or to tau detected by PET imaging. This disconnect implies that structural deterioration may precede — or simply run parallel to — the molecular and symptomatic markers of disease, without necessarily predicting CTE itself. Not every athlete exposed to repetitive impacts will develop the condition.
The researchers suggest that regional brain anatomy shapes vulnerability: the superior frontal sulcus, governing higher cognition, may accumulate mechanical strain across decades, while the occipitotemporal cortex, maturing earlier in development, may be more susceptible to damage accumulated over longer careers. Substantial validation work lies ahead — including studies bridging living patients and post-mortem findings — before sulcal morphology can reliably distinguish cumulative impact damage from CTE pathology itself. If that distinction is achieved, it could transform how medicine identifies and potentially intervenes in the lives of those most at risk.
An MRI study of former football players has found that repeated blows to the head leave measurable marks on the brain's architecture—specifically in the grooves that separate the brain's ridges, regions that show particular vulnerability to chronic traumatic encephalopathy. The research, published in Brain Communications, examined 169 former players with an average age of 57, comparing their brain scans to 54 non-players of similar age. What the investigators discovered was that the left superior frontal sulcus—one of the brain's deepest grooves—appeared noticeably shallower in the former athletes, and this shallowing correlated directly with how much cumulative head impact exposure they had endured during their playing careers.
Chronic traumatic encephalopathy, or CTE, is a progressive neurodegenerative disease linked to repetitive head trauma. It develops when a protein called tau accumulates abnormally in the brain, particularly in the depths of the sulci. This buildup triggers cortical atrophy—the brain tissue adjacent to the grooves literally shrinks—which makes the sulci wider and shallower over time. The condition has been documented in football players, boxers, and others in contact sports, but until now, researchers lacked a clear way to spot it in living patients. A definitive CTE diagnosis has only been possible after death, during autopsy.
The study's findings suggest that sulcal morphology—the shape and depth of these brain grooves—might serve as a more sensitive early warning signal than traditional measurements like cortical thickness or brain volume. The researchers used a specialized scale called CalcSulc to measure the width and depth of two key sulci in each hemisphere: the superior frontal sulcus and the occipitotemporal sulcus. The former players, drawn from the large multicenter DIAGNOSE CTE Research Project, included 114 who had played professionally and 55 who had played in college. The width of the left occipitotemporal sulcus, separately, correlated with how early in life a player had started the sport and how many years they had played.
But the findings also revealed a crucial limitation. The sulcal changes did not correlate with a clinical diagnosis of Traumatic Encephalopathy Syndrome, the symptom-based condition used to estimate CTE risk. They showed no relationship to neuropsychological test results or to flortaucipir PET imaging, a specialized brain scan that detects tau protein accumulation. This disconnect suggests that the structural changes visible on MRI may precede the molecular and clinical signs of disease—or that they reflect cumulative impact damage without necessarily indicating CTE itself. Not everyone exposed to repetitive head impacts develops CTE, and the study underscores that distinction.
The researchers theorize that the brain's anatomy makes certain regions more vulnerable to mechanical strain during impact. The superior frontal sulcus, which handles higher-level cognitive functions, may accumulate damage from sustained biomechanical stress over decades. The occipitotemporal cortex, which matures earlier in development, may be more easily damaged by impacts sustained over a longer playing career. This regional variation in vulnerability could explain why different sulci show different patterns of change.
The work opens a pathway toward better early detection of CTE risk, but significant validation work remains. The researchers acknowledge that structural MRI findings and molecular-level changes detected by PET imaging are only indirectly connected, suggesting that brain structure alone cannot yet reliably predict who will develop symptomatic disease. Future studies will need to examine both living and deceased patients to clarify how the sulcal changes caused by repetitive impacts differ from those that characterize actual CTE pathology. If that distinction can be reliably established, sulcal morphology could eventually become a tool for identifying high-risk individuals and potentially intervening before irreversible neurodegeneration takes hold.
Citações Notáveis
Sulcal morphology might be a more sensitive signal for CTE risk than conventional measurements like cortical thickness, volume, or surface area— Study findings in Brain Communications
A Conversa do Hearth Outra perspectiva sobre a história
So the study found that football players' brains look different on scans. But it didn't find that these differences predict who actually has CTE. Isn't that a problem?
It's more complicated than that. The structural changes are real and measurable—the grooves in the brain are genuinely shallower in former players. But yes, those changes don't line up perfectly with clinical diagnosis or with the molecular markers of CTE. That's actually important information. It tells us the structure changes first, before symptoms show up.
So you're saying the brain damage comes before the disease?
Not quite. The repetitive impacts cause structural changes—the brain tissue shrinks. Whether that structural change becomes CTE, with all its progressive neurodegeneration, is a separate question. Some people with these structural changes may never develop clinical disease. Others might. We don't know yet.
Why does that matter for a player reading this?
Because it means we might eventually be able to spot who's at highest risk before they start having cognitive problems or behavioral changes. Right now, you can only definitively diagnose CTE after death. If we can validate sulcal morphology as a reliable marker, a 45-year-old former player could get an MRI and know whether they need close monitoring.
But the study didn't show that the structural changes predict symptoms.
Correct. That's why more research is needed. The study shows the relationship between impacts and structure. The next step is understanding whether and when that structural change becomes clinical disease. It's the foundation, not the answer.