Selman, the idea for the episode was pitched by former staff writer George Meyer. In the episode's setpiece, Homer and Bart participate in a gross out contest, while Marge and Lisa are in the audience. According to Selman, the writers took inspiration from real gross out contests, which were "sweeping the nation" at the time. Before the contest in the episode, the spectators are given free samples of a pudding called Grandma Plopwell's. The name of the pudding was inspired by a brand of pies called Aunt Freshly, which the Simpsons writers usually ate at the time. The episode features the first official appearance of Lindsey Naegle, a sleazy businesswoman who has since become a recurring character in the series. While different versions of the character had appeared in the series before, namely in the season 8 episode "The Itchy & Scratchy & Poochie Show", the season 9 episode "Girly Edition", and the season 10 episode "Make Room for Lisa", the character's final design was first seen in "They Saved Lisa's Brain". The episode also mentions the character's name for the first time. Naegle's name was partly based on Selman's agent Sue Neagle, and Lindsey was chosen as the first name because Selman thought it sounded "annoying" and "pretentious". Naegle is voiced by Tress MacNeille, who Selman described as a "huge asset" to the series, and stated that she "breathes life" into the character. "They Saved Lisa's Brain" features English theoretical physicist and cosmologist Stephen Hawking as himself. According to executive producer and current showrunner Al Jean, Hawking was asked to guest-star because "we [they] were looking for someone much smarter than all the Mensa members [in Springfield]", and so they "naturally thought of him". Selman added that the Simpsons staff had heard that Hawking was a fan of the show, and that Hawking's family members wanted him to guest-star. Bill Mann of The Press Democrat argued that Hawking was chosen to guest star in order to boost the series' ratings during the May "sweeps". Mann wrote that "sweeps" are "used to set local TV ad rates for the months ahead". Hawking recorded his performance in the first week of December 1998. In her book Stephen Hawking: a biography, Kristen Larsen wrote that Hawking almost missed his recording session, as his wheelchair broke down two days before his flight to Los Angeles, where the recording took place. In order to