HOW LOUD MUSIC LEADS TO WHAT?

M. Charles Liberman, Ph.D., a professor at Harvard Medical School, explains how cranking up the dial can lead to lasting silence:

You are picking up big vibrations
Microseconds after the music begins, your outer ear catches sound waves and funnels them through your auditory canal to your eardrum, a thin, cone-shaped membrane. These waves vibrate the membrane. The louder the sound, the harder the eardrum beats.

Sound waves crash
The moving eardrum pushes against tiny bones in your middle ear called ossicles. When these bones oscillate, they cause waves of sound ferrying fluid to roll up your inner ear's cochlea, a conical chamber that houses some 10,000 hair cells. When tunes are blasting, these waves hit like surf during a storm.

Your brain goes electric
The waves cause the hair cells to sway. That movement is turned into electricity, which triggers the release of a chemical neurotransmitter that washes over neighboring never fibers. The fibers generate electrical spikes and carry the pulsing signals to your auditory cortex, where it registers sounds.

Signals are dropped
The barrage of chemicals from overloaded hair cells zaps neighboring nerve fibers, which means that some normally functioning hair cells have nowhere to send their signal. Other overworked cells become exhausted and die. The speed of this process depends on how much you have abused your ears.

What is that ringing?
Here is the funny thing about your brain: if it does not receive the signals it was expecting from your nerves, it tries to turn up the volume by producing abnormal nerve signals. That high pitched ringing you heard on your way home from that rock concert? That is the sound of your hearing dying.

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