Turn that iPod down, researchers warn

The warning from a panel of politicians and hearing-loss researchers in Washington DC rang loud and clear: turn down that iPod.

Or at the very least, don't blare the Apple gadget or other portable media players for hours on end, and think about investing in a pair of headphones designed to block background chatter and, in theory, stifle the need to crank up the volume in the first place.

Concern over hearing damage wreaked by noisy personal electronics is nothing new, but the booming sales of MP3 players and other such headphone-dependent gadgets could prompt a whole new breed of danger, audiologists cautioned at a press conference hosted by the American Speech-Language-Hearing Association, or ASHA.

Some evidence, they said, lies in a new ASHA-commissioned survey, released at Tuesday's event, about the listening habits of 1,000 adults and 301 high-school pupils. Random telephone interviews found that just more than half of the youngsters and less than 40 per cent of the adults had experienced at least one of four hearing-loss symptoms. Those symptoms included ringing in the ears, saying 'what' or 'huh' during 'normal' conversation, and turning up the volume on their television or radio.

The survey doesn't attribute the symptoms directly to the portable gadgets. It merely suggests the possibility of a connection -- noting, for instance, that 40 per cent of both students and adults reported setting their Apple iPods at what they'd consider 'somewhat loud' or 'extremely loud' volume levels. When the question was broadened to MP3 players in general, that number rose to about 60 per cent of teenagers and fell to about one-third of adults surveyed.

The new gadgets are especially ripe for additional study because of such factors as the ever-growing life of players' batteries, which promotes longer playback time, and the popular use of close-fitting earbuds, panelists said.

"Little research has been done on the impact of this new technology," said US Representative Edward Markey, a Massachusetts Democrat on the House Energy and Commerce Committee, which deals with technology issues. "We need to make sure that when millions of consumers plug up their ears to travel to work or work out, they are not taking on too much for their ears to handle."

Excessive noise to blame
Speaking at Tuesday's press conference, Markey and New Jersey Republican Mike Ferguson both pledged to push for greater research and education on the issue. In late January, Markey called on the National Institutes of Health to investigate a number of questions about possible connections between the newer portable media players and premature hearing loss. According to ASHA statistics, excessive noise is to blame for at least one-third of the more than 30 million Americans who report having significant hearing loss.

Such a setback in youngsters can prove especially devastating, said Anne Marie Tharpe, a Vanderbilt University audiology researcher. Her department recently studied 1,200 children deemed to have 'minimal' hearing loss and found they had lower standardised test scores, greater stress and behavioural problems, and lower energy levels and self-esteem than their 'normal-hearing' peers, she said.

Apple, for its part, already faces a class action lawsuit backed by a group of iPod users seeking compensation for hearing damage they claim was caused by the devices.

The suit alleges, among other things, that Apple has not limited the device's sound output to a safe decibel level for its American customers, despite complying with the French government's 100-decibel cap. (For comparison's sake, a chainsaw, a snowmobile and a motorcycle each produce about 100 decibels of noise, according to ASHA statistics.)

The US Congress would be wise to consider requiring such limits, said Northwestern University audiology researcher Dean Garstecki, emphasising that manufacturers "have an obligation to limit the output of the devices to a level that does not cause hearing loss."