Casie Keaton treats people with tinnitus, a persistent ringing or buzzing in the ears. She runs an audiology clinic in Collierville that specializes in the condition. She travels widely to study it, speaking at a conference in Denmark last year and spending several days this year learning from advanced specialists in England. “What I want people to know is there are very passionate people out there working on solutions to tinnitus,” she said. “There’s more research now than ever before.”