Try something

"well, that's too bad," said Silvanus. "Forget literally everything except how to breathe."

At once, the women's eyes glazed over and they literally collapsed into a pile, their bodies acting like jello. Quite literally, they had forgotten how to do everything but breathe, be it standing or thinking, judging by the drool now pooling on their chins.

"Girls?" Silvanus asked. "Hello?"

No response. They couldn't think of the words to respond, and even if they could, they couldn't remember how to talk. Just mindless husks.