The Deaflympics (previously called World Games for the Deaf, and International Games for the Deaf) are an International Olympic Committee (IOC)-sanctioned event at which deaf athletes compete at an elite level. Unlike the athletes in other IOC-sanctioned events (the Olympics, the Paralympics, and the Special Olympics), the Deaflympians cannot be guided by sounds (e.g., the starter's guns, bullhorn commands or referee whistles).
The games have been organized by the Comité International des Sports des Sourds (CISS, "The International Committee of Sports for the Deaf") since the first event in 1924.
The first games, held in Paris in 1924, were also the first ever international sporting event for athletes with a disability. The event has been held every four years since, apart from a break for World War II, and an additional event, the Deaflympic Winter Games, was added in 1949.
The games began as a small gathering of 148 athletes from nine European nations competing in the International Silent Games in Paris, France, in 1924; now, they have grown into a global movement.
Officially, the games were originally called the "International Games for the Deaf" from 1924 to 1965, but were sometimes also referred to as the "International Silent Games". From 1966 to 1999 they were called the "World Games for the Deaf", and occasionally referred to as the "World Silent Games". From 2001, the games have been known by their current name Deaflympics (often mistakenly called the Deaf Olympics).
To qualify for the games, athletes must have a hearing loss of at least 55 db in their "better ear". Hearing aids, cochlear implants and the like are not allowed to be used in competition, to place all athletes on the same level.
Other examples of ways the games vary from hearing competitions are the manner in which they are officiated. To address the issue of Deaflympians not being able to be guided by sounds, certain sports use alternative methods of commencing the game. For example, the football referees wave a flag instead of blowing a whistle; on the track, races are started by using a light, instead of a starter pistol. It is also customary for spectators not to cheer or clap, but rather to wave – usually with both hands.Source: https://en.wikipedia.org/wiki/Deaflympics