Joe Kapp, the rough-and-tumble quarterback who led the Vikings in their first Super Bowl appearance, said he has Alzheimer's disease and has decided to donate his brain after he dies for research into whether concussions he suffered during his playing days permanently damaged his mind.

In an interview with the San Jose Mercury News shortly before Sunday's Super Bowl up the freeway from his Bay Area home of Los Gatos, Calif., the 77-year-old Kapp also said he's dedicating a chapter of his in-progress memoir to concussions.

"It's past the time of concern," Kapp, who called signals for the Vikings in their January 1970 Super Bowl IV loss to Kansas City, told the newspaper. "Every single day I live being forgetful. I've got calendars on both of my shoes."

Kapp told the Mercury News he has pledged to donate his brain for research to neurologists at the University of California-San Francisco. "When I cash in, they'll take my brain and study it," he told the newspaper.

In a 1970 interview for a Sports Illustrated cover story titled "The Toughest Chicano," Kapp said, "I've been called 'one half of a collision looking for the other.' … You won't see me running out of bounds to avoid a little physical contact with a linebacker."

Kapp is among the many former football players who sued over brain damage and won a settlement with the NFL. The deal is on hold, however, as some players appeal.

Joe Kapp talked to coach Bud Grant in 1967, the first of Kapp’s three seasons playing Vikings quarterback.

Last week, researchers released information about another NFL quarterback in Kapp's era, the late Oakland Raiders legend Ken Stabler, saying he showed signs of a degenerative brain disease known as CTE.

Studies at Boston University revealed Stabler is the seventh former pro quarterback known to have suffered from CTE, the New York Times has reported. BU researchers have reported finding the disease in 90 of 94 brains of former NFL players they have examined.

The federal Centers for Disease Control and Prevention says that NFL players are four times more likely to suffer from Alzheimer's than the population as a whole.

Paul Walsh • 612-673-4482