Before its release in the United States, Sony decided that vibration feedback would be removed from the European and American versions of the controller. According to a Sony spokesperson, "We evaluated all the features and decided, for manufacturing reasons, that what was most important to gamers was the analog feature."[4] Reasons for dropping the vibration feedback reportedly included its being linked to premature malfunction of the controllers.[5][4] There were rumors that Nintendo had attempted to legally block the release of the controller in North America due to the vibration feature's similarity to Nintendo's Rumble Pak,[6] but Nintendo firmly denied that it had taken any form of legal action over Sony's controllers.[4] Moreover, according to the United States Patent Office, two employees of Atari Games have held a patent on vibrating game controller technology since March 1991.[7] Another theory for the vibration feedback being dropped was that Sony simply wanted to keep the price of the controller down so as to maximize user adoption.[4]