Loud Noises and Tinnitus

December 29th, 2011 by Charles Smithdeal MD ret

It is very distressing to experience a sudden onset of ringing in the ears. This condition is known as tinnitus. The noise of tinnitus may include ringing, screeching, buzzing, chirping, a hissing sound like steam escaping, or similar to the humming sound from high tension power lines.

People think that the sounds are in their ears, but they’re not. They are in the brain.

Tinnitus can result from a variety of causes. The most common cause is damage to the delicate sound-receiving hair cells within the inner ear. Exposure to a loud noise often damages these cells, resulting in a partial loss of hearing and the subsequent development of tinnitus. This condition is diagnosed as acoustic trauma. It is quite common in hunters, target shooters, police and military personnel, and anyone exposed without sufficient ear protection to loud gunfire or other loud noises.

What level of noise is safe? And how is sound measured? Loudness is actually the pressure of sound waves, and is recorded as decibels (dB.)

by *saxon* under CC BY

Loud Noises and Sound

A few examples of sound pressures are:

A whisper or a quiet library: 30 dB
Normal conversation: 45 to 60 dB
Alarm clock: 75 dB
Margarita Mixer: 85 dB
Home Garbage Disposal: 90 dB
Tractor or Truck without a muffler: 90 dB
Someone yelling: 90 dB
Power saw at 3 Ft away: 110 dB
Noisy nightclub with live music or DJ, Rock concert: 115 dB
Shotgun blast: 150 dB
Jet aircraft, 50 meters away: 140 dB
Cannon fire, 50 ft away: 200 dB

A “normal level” of sound (below 80 dB) will not damage your hearing. Prolonged or repeated exposure to sound levels above 85 dB will damage anyone’s hearing. A single exposure to sound above 135 to 140 dB may cause permanent damage to anyone’s hearing.

The cochlea is a snail-shaped organ inside the inner ear. Inside the cochlea are delicate hair cells. They receive sound vibrations when transmitted from the ear canal and past the eardrum. When the sound vibration is excessive, the cells can literally vibrate to death. When hearing is lost this way, the sound frequencies that suffer most are near 4000 cycles per second.

Sound vibrations occur in the environment and are transmitted via the inner ear and eighth cranial nerve as electromagnetic signals to the brain. When sound is totally absent in the environment, these brain cells search for replacement sounds, and 95% of people with normal hearing will develop tinnitus.

Brain cells that normally interpret signals from the auditory nerve become super sensitive when these signals are no longer present. They strain so hard to receive sound that they begin to pick up signals from adjacent brain cells, and interpret these signals as disorganized sound. Our brain interprets this as the bizarre sounds often described as tinnitus.

Visit Tinnitus to learn everything you’ve ever desired to understand about tinnitus. Dr Smithdeal is a former tinnitus sufferer and a board certified Otolaryngologist (ret.)

Click here for access to the Tinnitus Miracle.