To avoid cluttering the Trivia page (and all of these are speculations and not facts), I've moved all the possible sources of inspiration for the Screamers here. Below are a few of them:

• The Screamer, a planned enemy in Left 4 Dead that never made it into the game. It wears a straightjacket and screams to attract hordes. Its last appearance was supposedly in a trailer released in 2006.
• The Screamer from Silent Hill: Downpour. It can attack with arms at close range, and use the scream at longer distances to stun the player character. Note that SoD began development in 2009-2010 and SH:D was published in 2012.
• Michonne's armless and toothless pet walkers from the comic series The Walking Dead and the TV series adaptation. They look very similar to screamers and were introduced in 2005.
• The Siren from the Dead Frontier MMOG. It cannot attack physically, and only screams loudly to alert other zombies. DF beta came out in 2008, it's not known when Siren were introduced in the game.
• Any game designer with common sense, really. Just name any game where stealth is preferrable, there will be at least one type of loud enemy or object to mess with the player.

So, if you guys know any thing else that can be an inspiration (appearance or gameplay-wise) for the Screamers in any media, you can discuss them here. Note that they must make a public appearance in 2009-2010 or earlier to qualify.