What does loss mitigation mean
shaded region shows the level and
frequency of average speech
An audiogram is a graph that shows the softest sounds a person can hear at different pitches or frequencies. An “O” often is used to represent responses for the right ear and an “X” is used to represent responses for the left ear. There usually is a key on the audiogram; similar to one found on a map, that identifies what the different symbols mean. The closer the marks are to the top of the graph, the softer the sounds that can be heard. The audiogram shown above on the left indicates the different degrees of hearing loss.
The pitches shown on the audiogram are those most important for hearing and understanding conversation. Each sound we hear when someone speaks has a different pitch and loudness. For example, the “s” sound is high in pitch and quiet. The “o” sound is low in pitch and louder. The audiogram shown above on the right has a shaded area that shows the range of pitch and loudness for most speech sounds.
During a hearing test, sounds are presented in different ways. When testing with earphones or loudspeakers, the sounds go into
the ear canal, through the middle ear to reach the inner ear. This is known as air conduction testing. Air conduction testing looks at how the whole hearing system responds to sound.
If air conduction testing shows a hearing loss, another device called a bone vibrator is placed behind the ear to send sounds directly to the inner ear. Sounds are sent through the bones of the head and do not pass through the eardrum or the middle ear. This is called bone conduction testing.
When something stops sounds from moving through the eardrum and middle ear, bone conduction hearing levels will be better than air conduction levels. This means a conductive hearing loss is present. When sound moves normally through the outer and middle ear, but the inner ear does not work normally, both bone conduction and air conduction hearing levels will be the same. A sensorineural hearing loss is present.
The audiogram here shows a severe hearing loss. A child with this hearing loss may only hear very loud speech or loud environmental sounds, such as a fire truck siren or a door slamming.
Click for an example of severe hearing loss