There's no way to hear Glen Campbell's farewell album, "Adios," except through the prism of his rapid descent into Alzheimer's.

It's syrupy, laced with over-the-top emotion and full of can't-miss references to the challenges posed by Campbell's long, slow decline. And yet there is still the clear, familiar voice that touched so many in his long-running television variety show and on a string of albums that helped move country music into mainstream American culture.

Campbell's wife, Kim Campbell, says the new album gave her husband, now 81, a chance to say goodbye. How much say-so he had in that decision is unknown. But once Campbell's devoted fans get past the uneasiness of wondering whether he's being exploited, they'll find comfort in the voice they know and love.

The album, a collection of covers and songs Campbell cherished, includes collaborations with Willie Nelson, Roger Miller and Vince Gill. And no, it doesn't shy away from over-the-top sentimentality.

On "Postcards from Paris," for example, Campbell is joined by sons Cal and Shannon and daughter Ashley for the money line, "I wish you were here." The double-meaning reference to his illness can't be missed.

Nelson joins in on "Funny How Time Slips Away," again with obvious overtones.

Ultimately, you know you're not listening to a musical milestone here, but the songs are pleasant enough. And remembering that Campbell found comfort in being onstage even after his mind began to slip, you hope being in the studio was good for him, too.