ASK DR. BAUGHAN                                                         February 5, 1999

EARS THAT GO POP

Hearing is an under-appreciated sense.  The middle ear is a space about the size of a thimble that can transmit the incredible range of sounds of a solo flute to a Beethoven symphony from invisible sound waves to motion of a thin membrane (the eardrum) to jiggling of three tiny bones (the hammer, anvil and stirrup - or the malleus, incus and stapes if you want to be precise) to vibration of an even smaller membrane, the oval window, which leads to the inner ear.  When the oval window pushes in, the fluid in the inner ear must have somewhere to go, so next to the oval window is the round window, another thin membrane, which can bulge out when the oval window bulges in.

For these delicate bones and membranes to vibrate with the subtlety intended, the air pressure on the inside or outside of the eardrum must be equal, since the middle ear is supposed to be air filled.  So Nature installed a pressure valve, the Eustachian tube.  This goes from the middle ear to the back of the throat.  Usually it is collapsed, but a muscle in the back of the throat can pull it open.  This happens with chewing and yawning, which is why your ears may “pop” when changing altitude.

Sudden or extreme changes in pressure on either side of the eardrum can cause damage to the most vulnerable components of the system, the eardrum or the membrane of the round window.  The most common injury is from scuba diving.  Water pressure increases rapidly with depth, so the pressure on the outside of the eardrum can quickly become intense if the Eustachian tube is not opening easily and frequently to equalize the pressure in the middle ear.  If the pressure does not equalize, the eardrum can be painfully stretched or even rupture.  Transmitted pressure can damage the round window if it is a little less tough than the eardrum.  Almost everyone who has ever flown in an airplane has felt discomfort in their ears on take-off and landing.  On take-off, the air pressure drops, so the outside pressure is less than the pressure inside the middle ear.  The eardrum will bulge outward until the Eustachian tube opens to equalize the pressure.  On landing, the outside pressure increases, so the drum bows in.  Thinner eardrums, such as in babies, will be more sensitive to pressure changes, thus hurt more or be more at risk for injuries.

When a person has a cold or an ear infection, this pressure valve may not open well, and the membranes may be more vulnerable.  I am not aware of any sadistic researcher who has determined just how much pressure and how quickly applied is necessary to rupture an eardrum, which can cause intense pain and temporary hearing loss, or rupture of the round window, which can cause permanent hearing loss.  But one concern for our region is the ski slopes.  If you have a cold or ear pressure, be careful about taking the lifts to higher altitudes to the peaks.  The lower lifts may not be bad, but there have been reports of hearing loss due to these type of injuries taking the high-speed lifts (less time to equilibrate) 2000 feet up (higher pressure change) in cold weather (tissues stiffer and more difficult to open the Eustachian tube).  If you feel pain in your ears, try to get to lower altitude as soon as possible, and if you feel fullness or pressure in your ears in the first place, stay at lower elevations.

So respect your hearing.  Protect your ears.  Avoid noise abuse.  We would have immediate compassion for anyone who is blind.  Why do we often initially respond with contempt or insults for hearing loss?  “Whattsa matter, are you deaf or something?”