Her family said asked for privacy for Mondale, 83, "as her life on this earth moves peacefully to its close," the (Minneapolis) Star Tribune reported. Developments would be issued through Westminster Presbyterian Church, where they are members, the newspaper said.
While her 86-year-old husband was a political power as a U.S. senator, vice president and U.S. ambassador to Japan, Mondale has been known as a strong advocate for the arts.
Warren MacKenzie, 89, who taught Mondale pottery techniques, told the newspaper he wasn't privy to the specifics of her illness.
"All we saw was a slow disintegration of her control of things," he said. "She lost her memory."
He said her last trip to his studio in Stillwater, Minn., took place a couple of months ago.
"She was really fading rapidly. She was in a wheelchair," he said. "She couldn't carry on much of a conversation, and so the conversation moved around her without really involving her. But she was very happy with that, just to associate with things that she had known."