Lassie..?

8/13/81 President Reagan takes time out from his summer vacation at his home in Santa Barbara, California – which is oddly called a “ranch” though no livestock or crops are raised there – to sign the largest budget and tax cuts in history into law. When his dog wanders by, a reporter asks its name. “Lassie,” the President replies, then corrects himself. “Millie!” he says. “Millie. Millie’s her name.” Everyone laughs and laughs, because it’s just so funny when someone forgets his own dog’s name and confuses her with a movie dog.

I always thought it was through his second term that Reagan's brain turned into apple sauce, but it was actually pretty soon after his assassination recovery in '81 that it started to manifest. The above wasn't the first, there ended up being many. In principle, reduction of mental capacity & atrophy isn't something to made fun of, but the situation and the scale of the constant covering up by his team is worth a chuckle.

Above sourced from this book: http://www.theclotheshavenoemperor.com/

& website: https://dangerousminds.net/comments/reagan_cant_remember_his_dogs_name_1981