Researchers have discovered that a protein marker for Alzheimer's disease could help detect chronic traumatic encephalopathy (CTE) in living patients, according to early findings reported in Science News.

CTE develops from repeated head impacts in contact sports like football and boxing. Currently, doctors can only confirm CTE through brain autopsy after death, making early intervention impossible. The new approach offers a potential pathway to diagnosis while patients remain alive.

The protein in question is phosphorylated tau, a misfolded protein that accumulates in Alzheimer's patients' brains. Scientists found that this same protein also appears in CTE cases, suggesting a biological connection between the two neurodegenerative conditions. Both diseases involve tau tangles that damage brain tissue over time.

The research builds on advances in cerebrospinal fluid testing and blood biomarkers that can now detect phosphorylated tau forms without requiring brain tissue samples. If validated in larger studies, these tests could identify CTE in former athletes and active players before severe cognitive decline occurs.

The findings remain preliminary. Researchers have not yet established whether phosphorylated tau levels alone can reliably distinguish CTE from Alzheimer's or other conditions that produce similar protein patterns. The specificity and sensitivity of such tests in real-world populations require further investigation.

The work addresses a pressing public health concern. Thousands of former athletes face uncertain cognitive futures after careers in contact sports. A blood or fluid test for CTE could enable earlier medical management, lifestyle modifications, and enrollment in clinical trials for emerging treatments. It may also provide evidence for policy changes in youth sports regarding head injury prevention.

Scientists emphasize that detecting tau protein represents one piece of the diagnostic puzzle. CTE involves other pathological changes including TDP-43 protein aggregation and neuroinflammation. A comprehensive diagnostic approach will likely require multiple biomarkers tested together rather than reliance on