Results from a hearing test are displayed on an audiogram. An audiogram is a graph that shows the softest sounds a person can hear at different pitches or frequencies. The closer the marks are to the top of the graph, the softer the sounds that person can hear. Where the patient’s results fall on the audiogram indicate the different degrees of hearing loss. The audiogram shown below indicates the different degrees of hearing loss.
An “O” often is used to represent responses for the right ear and an “X” is used to represent responses for the left ear. A key on the audiogram, similar to one found on a map, identifies what the different symbols mean.
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 below has a shaded area that shows the range of pitch and loudness for most speech sounds.
How Does An Audiogram Measure Hearing?
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, bone conduction testing is used. A 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. 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.