CTE — chronic traumatic encephalopathy — is a degenerative brain disease found in many former professional football and hockey players, for whom blows to the head have long been part of the job.

But those injuries also occur outside the world of pro sports. And as awareness of CTE has grown, so has a thriving market of dubious remedies marketed to everyday people who believe they are suffering from CTE — a disease that can't even be diagnosed until after death, through an autopsy of the brain. Sacha Pfeiffer of NPR's Investigative Team reports on some of those desperate patients and their search for a cure.