(…) Mark and I sat at opposite ends of a long coffee table, in the living room, and his parents sat on the couch. He took off his earmuffs but didn’t put them away. “I was living in California and working in a noisy restaurant,” he said. “Somebody would drop a plate or do something loud, and I would have a flash of ear pain. I would just kind of think to myself, Wow, that hurt—why was nobody else bothered by that?” Then everything suddenly got much worse. Quiet sounds seemed loud to him, and loud sounds were unendurable. Discomfort from a single incident could last for days. He quit his job and moved back in with his parents. On his flight home, he leaned all the way forward in his seat and covered his ears with his hands. (...) That was five years ago. Mark’s condition is called hyperacusis. It can be caused by overexposure to loud sounds, although no one knows why some people are more susceptible than others. There is no known cure. Before the onset of his symptoms, Mark lived a life that was noise-filled but similar to those of millions of his contemporaries: garage band, earbuds, crowded bars, concerts. The pain feels like “raw inflammation,” he said, and is accompanied by pressure on his ears and his temples, by tension in the back of his head, and, occasionally, by an especially disturbing form of tinnitus: “You and I would have a conversation, and then after you’d left I’d go upstairs and some phrase you had been saying would repeat over and over in my ear, almost like a song when they have the reverb going.” He manages his condition better than he did five years ago, but he still lives with his parents and doesn’t have a job. The day before my visit, he had winced when his father crumpled a plastic cookie package that he was putting in the recycling bin. By the end of our conversation, which lasted a little more than an hour, he had put his earmuffs back on. (...) In 1999, two scientists at the University of Manchester, in England, conducted an experiment in which they had students listen to songs at dance-club volumes, which are high enough to cause permanent damage if the exposures are long enough. The scientists concluded that the loud music stimulated the parts of the subjects’ inner ears that govern balance and spatial orientation, thereby creating “pleasurable sensations of self-motion”: crank up the volume, and you feel as though you’re dancing when you’re sitting in your seat. (...) Studies have shown that people who live or work in loud environments are particularly susceptible to many alarming problems, including heart disease, high blood pressure, low birth weight, and all the physical, cognitive, and emotional issues that arise from being too distracted to focus on complex tasks and from never getting enough sleep. (…)