March 29, 2008

Ringing Ears

Stupid Question ™
Jan. 19, 2004
By John Ruch
© 2004

Q: What are you actually hearing when your ears are ringing?
—Toaste, Columbus, Ohio

A: The real question is, what are you “actually” hearing when you hear anything? Fact is, whether we’re detecting actual sound waves in the atmosphere or just plain hallucinating, we experience sound in our brains, not in our ears. And that may be the key to the weird mystery of ringing ears.

You’re talking about tinnitus, an umbrella term for any disorder in which the sufferer hears a persistent noise for which there is no apparent cause. It tends to center in one or both ears. It can be permanent, or it can be temporary, such as the ringing induced by loud rock concerts or gunfire (though the damage caused by such sound may bring the tinnitus back in a more permanent form later).

The sound can be a ringing, hissing, clicking, whining, whistling, rumbling—basically anything you can think of. It can have single or multiple tones; it can be continuous or jump on and off; it can range widely in volume.

One thing certain about tinnitus: noise damage to the ear (either to the auditory nerve or to microscopic hairs within the ear that help make hearing possible) induces it. Another thing we know is that auditory neurons in both the ear and the auditory center of the brain appear to fire constantly at a low level whether sound is present or not; thus hearing may blot out sound that otherwise covers up this general this general fake noise created by the buzzing brain itself. (That is, if these neural firings actually take place and actually take the form of hallucinatory sound in the brain.)

The idea that tinnitus is revealing this ongoing, underlying buzz is supported by the fact that some tinnitus can be treated by blocking it out with white noise produced by a hearing aid device, or by electrode stimulus of the nerves.

However, in other cases, even severing the auditory nerves doesn’t do anything to stop tinnitus. Likewise, tinnitus has been correlated with other conditions such as ear wax build-up, medicine side effects and even high blood pressure.

Audiologists like to classify tinnitus as either “subjective,” meaning there is no organic cause, and “objective,” meaning there is an organic cause. They say the vast majority of cases are subjective.

This is basically nonsense because nobody really knows what makes tinnitus happen in the brain. Some rogues even claim that all tinnitus is objective, caused by an ability to hear blood flowing in the ear or a similar oddity. There’s no doubt that some strange noises can be ascribed to jaw problems and the like, but it’s not clear if this is really tinnitus as we know it. In any case, these theories struggle to explain “subjective” tinnitus.

Another suggestion is that tinnitus is related to the “phantom limb” phenomenon in which people who lose a limb (or, less drastically, have all nerve connections to a body part severed) experience a feeling (ranging from normal sensation to just blinding, abstract pain) that appears to be located in the missing/detached body part.

The idea is that the dead hair cells or nerve cells in the ear may result in a sort of phantom sound.

It’s an intriguing theory, though not very helpful since the phantom limb phenomenon is itself far from understood. Also, the phantom limb syndromes seem to be much more complex in nature and effect than tinnitus.

What are all these people feeling and hearing if there’s nothing there to feel or hear? The answer quickly leads you away from “Gray’s Anatomy” and closer to Kant’s metaphysics.

Both phenomena are great reminders that biology and physiology can be hard to reduce to a simple organic answer, because the mind/body duality and the riddle of the senses still stump us. To really find out what tinnitus is, we may have to ask if there’s a doctor in the house—a doctor of philosophy, that is.

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