The Apple iPod, currently the world’s best-selling line of digital audio players, was unveiled in 2001 for the Mac, and in 2002 for Windows. iPods store and play songs in a variety of digital formats, including MP3, Apple Lossless, and AAC. The combination of sound quality, sleek design, and slick user interface, coupled with a bold marketing campaign, has made the iPod a hit. By the end of 2006, over 67 million iPods had been sold. What medical problem may be associated with prolonged iPod use? Discuss