In this page we will explain some things about hearing loss that you may not know. Remember that not all hearing loss is the same and in order to properly diagnose hearing loss you should get a hearing exam from a licensed specialist.
Non-genetic factors can account for about 25% of congenital hearing loss. Non-genetic factors that are known to cause congenital hearing loss include:
Genetic factors (hereditary) are thought to cause more than 50% of all hearing loss. Hearing loss from genetic defects can be present at birth or develop later on in life. Most genetic hearing loss can be described as autosomal recessive or autosomal dominant. Other, more rare types of genetic hearing loss include X-linked (related to the sex chromosome) or mitochondrial inheritance patterns.
Acquired hearing loss is a hearing loss that appears after birth. The hearing loss can occur at any time in one’s life, as a result of an illness or injury. The following are examples of conditions that can cause acquired hearing loss:
Loud noise can be very damaging to hearing. Both the level of noise and the length of time you listen to the noise can put you at risk for noise-induced hearing loss. Noise levels are measured in decibels, or dB for short. The higher the decibel level, the louder the noise. Sounds that are louder than 85 dB can cause permanent hearing loss. The hearing system can be injured not only by a loud blast or explosion but also by prolonged exposure to high noise levels.
How loud is too loud?
The noise chart below lists average decibel levels for everyday sounds around you.
150 dB = fireworks at 3 feet
140 dB = firearms, jet engine
130 dB = jackhammer
120 dB = jet plane takeoff, siren
110 dB = maximum output of some MP3 players, model airplane, chain saw
106 dB = gas lawn mower, snowblower
100 dB = hand drill, pneumatic drill
90 dB = subway, passing motorcycle
80–90 dB = blow-dryer, kitchen blender, food processor
70 dB = busy traffic, vacuum cleaner, alarm clock
60 dB = typical conversation, dishwasher, clothes dryer
50 dB = moderate rainfall
40 dB = quiet room
30 dB = whisper, quiet library
How can I tell if I am listening to dangerous noise levels?
How can loud noise damage hearing?
Understanding how we hear will help you to understand how loud noise can hurt your hearing.
One of the most common bad effects of loud noise on hearing is a permanent hearing loss. This happens in the following way:
Hearing loss can be categorized by which part of the auditory system is damaged. There are three basic types of hearing loss:
Conductive hearing loss occurs when sound is not conducted efficiently through the outer earcanal to the eardrum and the tiny bones (ossicles) of the middle ear. Conductive hearing loss usually involves a reduction in sound level or the ability to hear faint sounds. This type of hearing loss can often be corrected medically or surgically.
Some possible causes of conductive hearing loss:
Sensorineural hearing loss (SNHL) occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain. Most of the time, SNHL cannot be medically or surgically corrected. This is the most common type of permanent hearing loss.
SNHL reduces the ability to hear faint sounds. Even when speech is loud enough to hear, it may still be unclear or sound muffled.
Some possible causes of SNHL:
Sometimes a conductive hearing loss occurs in combination with a sensorineural hearing loss(SNHL). In other words, there may be damage in the outer or middle ear and in the inner ear(cochlea) or auditory nerve. When this occurs, the hearing loss is referred to as a mixed hearing loss.