Researchers are becoming increasingly concerned about the adverse effects of and the hearing loss caused by the increase in popularity of portable music devices among young people.

Robert Novak, director of clinical education in audiology at Purdue University, has been documenting young people's hearing for years. As portable music devices have increased in popularity, he has documented an alarming trend.

Each year since the debut of the early Sony Walkman in 1979, Novak has found that college freshmen have exponentially more hearing loss and have continued to develop hearing problems as they continue in college.

Hearing loss can result from concerts, parties, traffic and other sources of loud noise, but the main culprit for the increase in severity of the damage is the increase in the portability of music.

"It's not the headphones causing the damage, what is causing the damage is the convenience of these devices today," said Edward Korabic, associate professor of speech pathology and audiology, referring to portable music devices like CD players and MP3 players.

From the days of home stereos and boom boxes to the portable CD player and MP3 players, people are able to listen to their music more often. Instead of listening to music during certain parts of a day, music listening has become an all-day activity for many young people, which can overload their delicate hearing structures.

"Even when I'm in class I listen to (my MP3 player)," said Drew Parrin, a freshman in the College of Arts & Sciences. "I will listen to it everywhere, in between classes and even when I'm doing homework. I'll probably spend anywhere from six to 10 hours a day listening to it."

Due to the increasing portability of music, ears can be damaged more easily than before due to the duration of listening. Listening to four hours of music at 95 decibels is considered safe, according to Korabic. Ninety-five decibels is about the level of volume of a lawn mower or electric drill.

However, if either the duration or the intensity of the listening increases, the other factor must decrease to avoid hearing loss.

"The person must have control of either the duration or intensity," Korabic said. "If your decibels go up, then you must decrease the duration. Control is the key."

Abusing either one or both of these two factors can lead to serious hearing loss symptoms. A condition known as temporary threshold shift occurs when a person leaves a concert or takes out their headphones and can still hear the music or ringing in their ears. If the activity is repeated often, then permanent threshold shift occurs. The ringing is called tinnitus.

"When you take (headphones) out there is a readjusting period. You have to get used to your surroundings again," Parrin said. "There may be a slight ringing or steady noise going off that you have to get used to."

These effects on hearing are irreparable.

"In the ear there are hair cells, the sensory cells for hearing," Korabic said. "Until stimulated, there is no sensation of sound. What happens is when noise comes through the ear, it programs these cells to commit suicide. Once they are gone, they are gone. They cannot come back."

With no end to the growing trend of early-age hearing loss in sight, researchers are trying to promote good use of headphone devices to curb the growing rate of hearing problems among youth.

"These devices are not inherently dangerous, it's how the person uses them," Korabic said. "A good rule is when you are talking to someone one meter away with headphones on and you have to raise your voice, then it is too loud."

This article was published in The Marquette Tribune on September 22, 2005.