A growing number of high school students and adults are reporting early signs of hearing loss, and hearing experts think they know the culprits: iPods and similar portable devices that allow people to funnel loud sounds into their ears for hours on end. More research is needed to conclusively establish the link, but scientists suspect the increasing prevalence of the devices is contributing to the rising number of people reporting some form of hearing loss. "While the cause of the symptoms was not identified, the polling showed that people are listening louder and longer--habits made easier by strides in listening technology, but ones that may also contribute to hearing damage,\" said Alex Johnson, chairman of the audiology and speech-language pathology department at Wayne State and president of the American Speech-Language-Hearing Association.