Noise induced hearing loss is damage that occurs to the sensitive hearing hair cells inside your inner ear specifically in the cochlea. Loud sound travels down your ear canal to your eardrum. The eardrum vibrates and transfers the loud sound to the bones of the middle ear. These bones move and transfers the sound to the cochlea. Inside the cochlea are the hair cells which pick up different frequencies and pass this signal along the nerve to the brain. The force of loud sound causes damage to the hair cells of the cochlea. This cochlea is a delicate organ of hearing and once damage has occurred the damage is permanent. The extent of the damage that occurs depends on the level of loudness and the amount of time spent in that noise.
Noise of 85dB or louder is considered dangerous levels of noise. The louder the noise becomes the shorter the time is that a person is allowed to be exposed before permanent damage has occurred. The rule is if the loudness increases by 3dB the time allowed in that environment is halved.
How loud does a sound have to be before it causes damage to your hearing?
85dB loudness, for example a hairdryer, is safe for 8 hours
91dB loudness, for example a passing motorbike, is safe for 2 hours
97dB loudness, for example a hand drill, is safe for 30 minutes
109dB loudness, for example a chainsaw, is safe for 2 minutes
118dB loudness, for example an aeroplane taking off, is safe for 14 seconds
What could cause noise induced hearing loss:
- Loud music through iPod or music player
- Loud sounds through gaming devices
- Loud music in gyms
- Loud music at parties or dance venues
In adults, in conjunction with the above list:
- Loud machinery noise
Is your music too loud?:
- You have to raise your voice to be heard over the noise
- You can’t hear someone a meter away
- Others can hear the words of the song you are listening to through your headphones
- Speech is dull after you have been exposed to the noise
- You have ringing in your ears after being exposed to the noise
What are the signs of noise induced hearing loss?:
There is no obvious effects at first. Immediately after a prolonged exposure to noise a temporary thresholds shift in hearing will occur where temporary dulling of sound and ringing in the ears will be experienced for a few days. This may feel like your ears are blocked.
Prolonged exposure to loud noise can lead to significant hearing loss and ringing in the ears. A child’s greatest difficulty may be hearing in a noisy classroom.
What to do to prevent noise induced hearing loss:
Prevention is the better than cure
- Buy limited headphones, limiting loudness output to 85dB
- Lower the maximum volume setting in your music device. This is often in the settings of the device.
- Set the loudness level in the quite, and then don’t adjust it.
- Set your duration of exposure to short durations, taking small breaks of 15-20minutes between. This will allow the ear to rest and recover.
- Change your earphones to the smaller earbud earphones. This allows for some sound to escape while the larger over the ear earphones have bigger transducers and allow for a more powerful output.
What to do if you expect damage may have occurred:
Consult an audiologist to conduct a hearing assessment. Assessments should include a baseline audiogram as well as otoacoustic emission testing.