Former fighter and Ivy League football player Mark Tullius confronts the brain-injury symptoms that changed his behavior, relationships, memory, and sense of self.

For years, Mark Tullius ignored the warning signs. A former Brown University football player, boxer, and mixed martial artist, he'd learned to treat pain and repeated blows to the head as proof he was tough enough to keep going.

Then the symptoms stopped being ignorable. Memory, focus, mood, behavior, relationships, his very sense of self, all of it started to shift. TBI or CTE follows his search for answers about traumatic brain injury, the possibility of CTE, and the long work of rebuilding a life around invisible damage.

Candid, personal, and hopeful, it's about what brain injury does to an athlete and the people who love him, and why recognizing the symptoms matters before denial does more harm.

For readers interested in brain health, contact sports, and honest, hard-won memoir.

A memoir and an awareness resource, not a substitute for medical diagnosis or care.