NASHVILLE, Tenn. (AP) — Glen Campbell's Alzheimer's disease has progressed too far to allow him to continue touring.

Instead, he'll spend his 77th birthday on Monday in Washington as an advocate for Alzheimer's research. The trip includes a fundraising dinner for the Alzheimer's Association and a visit to Capitol Hill, where he'll visit the Senate.

Alzheimer's has robbed Campbell of many of his best memories, gained over a lifetime as an entertainment icon who was a pop star, a groundbreaking session musician, an actor and TV variety show host. But it hasn't taken everything.

Campbell will release a new album, "See You There," on July 30. It's a reimagining of some of his most popular songs, recorded by Julian Raymond during the same sessions that produced Campbell's last studio album of all new material, 2011's "Ghost on the Canvas."

The album offers new versions of his biggest hits like "Wichita Lineman," ''By the Time I Get to Phoenix," ''Rhinestone Cowboy" and "Hey Little One."

In a brief interview, Campbell said of the songs: "Oh, they're great. Those are great."

His wife, Kim Campbell, says her husband still occasionally lays down vocal tracks in the studio but the disease has progressed too far to allow him to continue touring, something the family and Campbell's management left open when he wrapped up his successful goodbye world tour last year.

"Glen still wants to record, but it's just a matter of if he's able to," Kim Campbell said. "It just gets more and more difficult for him all the time."

He remains healthy and vigorous and continues to play golf. His family invites musicians over to the house from time to time — songwriter Jimmy Webb, who wrote some of Campbell's most iconic hits, visited with his family over the weekend — and Campbell joins in on jam sessions, playing the guitar as if the progressive, irreversible neurological disorder has yet to touch his muscle memory.

"We're trying to live our lives and stay out there and socialize as much as we can as long as we can," she said. "The other night we went to see Merle Haggard and hung out with Toby Keith on his bus. ... Everybody played different songs and had a great time. So we're still out there trying to do that kind of stuff. But eventually we might not be able to do that."

Surfdog Records owner Dave Kaplan says "See You There" is meant to feel like sitting next to Campbell in the living room, the way he was introduced to him on "The Goodtime Hour." The singer's voice has changed enough with age that the songs take on a new life. Kaplan took Raymond's vocal recordings and surrounded them with music meant to leave lots of space for the singer's voice.

"I was immediately struck that they were kind of intimate and they definitely shook your spine," Kaplan said. "They were haunting and stunning and had this new intimacy in a way I hadn't heard these songs."

It was hearing Campbell sing "Hey Little One," with its simple opening, that convinced Kaplan it was OK to mess with the perfection of the originals.

"You just don't hear that on planet Earth," he said. "You don't just hear that. That sealed the deal in three words."

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