Not long ago electronics researcher Patrick Zurek, studying the way sounds entering the ear interfere with each other, put a tiny microphone to his own ear. To his surprise, he heard his ear whistling.
The sounds were not echoes, nor was it a case of tinnitus -- the ringing or roaring sounds some people complain of hearing in their ears. Rather, it was a steady broadcast from the inside of his right ear. When he tested his left ear, he found a similar high-pitched whistle being broadcast from it.
He quickly asked a colleague to put a "bug" in his ear as well. His colleague's ears spoke even louder than Zurek's. Knowing he was onto something, Zurek began a series of experiments with William Clark at the Central Institute for the Deaf in St. Louis, to look for ear broadcasts in animals and people.
The ear, it turns out, not only receives but also sends out its own signals. When he began to check the medical literature, Zurek found several references to the phenomenon: in one case, a young woman's ear gave off a whistle loud enough to be heard by others a couple of feet away.
Whenever the woman tried to play piano duets with her sister, the sister complained that she couldn't concentrate on what she was playing because of her sister's ear whistle.
Zurek also came across several cases in which anxious parents had brought infants and children to doctors in hopes of a cure or an explanation of the odd noise coming from the children's ears.
Zurek's work is one of several unusual findings in the study of hearing in the past two or three years. In England, researchers found that when sounds are aimed into the ear canal, echoes are returned. It had never occurred to researchers to look for echoes in the ear before, Zurek said, because the assumption has been "that it was a one-way street. Sounds went in and were never seen again."
Another interesting finding in the work of Zurek and British researchers is that once sounds enter the ear canal, they interfere with each other. Two sounds meeting in the ear canal distort one another, and set up other, harmonic tones as well.
The electronics work on acoustics has created a new area of research in the dynamics of hearing. Zurek even speculates that the ear whistling may be the indicator of a slightly damaged "feedback" system in the ear -- a system that might help the ear adjust by monitoring incoming sounds and amplifying or filtering noises. Such a system, if it exists, was unkown until Zurek stuck the microphone in his ear.
Both the whistling ear and the interference patterns apparently originiate in the cochlea, the fluid-filled spiral tube behind the eardrum. It is in the cochlea that the sound waves are conveyed to nerve ends, and thus became signals that are sent on to the brain.
Paradoxically, it has been found that the ears with the healthiest cochlea produce the greatest distortion in incoming sounds. Damaged cochlea produce very little distortion in incoming sound, for reasons the researchers haven't yet uncovered.
Zurek said it is conceivable that the difference in distortion patterns might at some time be able to give accurate diagnoses of healthy or damaged cochlea. If healthy cochlea produce one kind of distortion, and damaged cochlea produce another, testing for the differences could allow doctors to recognize and treat the damaged cochlea.
Doctors over the years haven't known just what to make of the complaints of whistling ears, especially because of the fact that even those with the loudest ear whisltes cannot hear their own ears whistling.
In Zurek's experiments, 32 people were checked for ear broadcasts, and exactly half were found to have them. Several had the whistle in two ears.
In testing 22 chinchillas, Zurek found no ear tones. But after giving the animals some doses of medium-loud noises, they found that two of the animals had developed full-blown cases of whistling ear.
In humans and animals, the whistling is steady and continuous, never stopping except when interferred with by other sounds coming into the ear.
Tinnitus -- the ringing in the ears -- is, by the way, apparently unconnected to the whistling ear phenomenon. Zurek tested some people who complain of tinnitus, and found that their ears do not whistle