The ability to communicate with the authorities by text in an emergency is limited to less than 10 percent of the U.S., says Scott Carlton, the creative director at Saatchi & Saatchi Wellness in New York City. Carlton is one of the masterminds behind Deaf 911, an emergency mobile app that gives people who are deaf or hard of hearing a voice when they need it most. Carlton doesn’t have a hearing loss, but his grandmother, with whom he was close, was profoundly deaf.