Hundreds of thousands of children with attention deficit hyperactivity disorder may be incorrectly diagnosed and may instead have trouble deciphering what they are hearing, audiologists say.
Doctors estimate 5 percent of all children have been diagnosed with attention deficit disorder, which translates to about 2 million to 3 million children. Frank Musiek, director of audiology at the Dartmouth-Hitchcock Medical Center in Lebanon, N.H., believes many of these youngsters — as many as 2 to 3 percent of all school-age children — may instead have a central auditory processing disorder.
In this disorder — a kind of dyslexia of the ear — the brain misprocesses sounds, says Musiek, who organized a conference of audiologists held this past weekend at Dartmouth College.
“These children can’t distinguish foreground signals from background noise,” Musiek says, likening it to the “cocktail party effect” — when you can’t hear people beside you because of background chatter.
Hard to Distinguish
The common traits of attention deficit disorder — inattention, distraction, hyperactivity — overlap with the behavior of kids with auditory processing disorders, who have difficulty hearing and thus have poor listening skills and trouble following instructions.
“The symptoms can mimic attention deficit disorder,” agrees Robert Sweetow, director of audiology and professor of otolaryngology at University of California at San Francisco. “The kid who can’t sit still — maybe what he’s hearing is so scrambled, he doesn’t give a damn.”
“Auditory processing disorder is a sleeping giant. Not enough people know about it to even consider it,” Musiek says. “Too many people look at these overlapping symptoms and say, ‘It must be AD/HD.’ We’re trying to say, ‘Why not have them evaluated for this as well?’”
The cause of auditory processing dysfunction in adults can include a knock to the head or a lesion in the part of the brain that controls auditory processing, the primary auditory cortex, Musiek says. In children, it may be caused by incomplete wiring of those neurons, or a delay in maturation that can later correct itself.
But diagnosing the syndrome is tricky because it is often missed by standard hearing tests, which only test the ability to hear tones at different frequencies.
Diagnosing an auditory processing disorder involves finding a properly trained audiologist who can run advanced electrophysiological tests, such as attaching elecrotrodes to the head to record how the brain responds to sounds. These tests cost from $250 to $1,000.
“In the hands of an expert, these tools can effectively diagnose kids who truly have an auditory processing problem,” Sweetow says. “But I have some trepidation that not all audiologists are adequately trained in this area.”
“We audiologists need to gear up,” Musiek agrees. “The typical audiologist gets very little training in this difficult area involving the brain.”
Training the Ear Treatments are available for these children, including software packages such as Fast Forward or Earobics that the child can use to do auditory exercises, such as listening to acoustically modified speech.
Another option is attaching a microphone on the teacher that transmits a signal directly to an assisted listening device that the child wears in his or her ear, allowing clearer hearing.