An audiogram is a graph which indicates how well one hears a range of sounds. An audiogram indicates the softest levels of sounds that a person can hear. It is used to determine whether a person is hearing within normal limits, or whether a person has a hearing loss. It also indicates the nature of the hearing loss i.e. conductive, sensorineural or mixed. Using an audiometer, the tester will produce different pitches at varying levels of loudness. The softest sound that the individual can hear at each pitch is recorded on the audiogram.  Using an audiometer, the tester will produce different pitches at varying levels of loudness. The softest sound that the individual can hear at each pitch is recorded on the audiogram.  In decibels (dB). The decibel is the unit of measurement for loudness. On the audiogram, the range of decibels is displayed along the vertical axis and extends from -10 dB to 120 dB. -10 dB represents extremely soft levels, whereas 120 dB represents extremely loud levels.

How are the different pitches measured?

Hertz (Hz) are the unit of measurement for pitch. On the audiogram, the range of pitches is displayed along the horizontal axis and extends from 125 Hz to 8000 Hz. Like a piano, the pitches start off low (125 Hz) and end up in the high range (8000 Hz). The pitches used in hearing testing are most often 250, 500, 1000, 2000, 4000 and 8000 Hz. These are the pitches most important for speech.

Speech Frequencies

Low-pitched sounds (ex., 250 & 500 Hz) include most of the vowel sounds as well as consonants such as "m," "n," "b," and "g."High-pitched sounds ( 2000 - 6000 Hz) include many consonant sounds such as "s," "t," "f" and "sh." The other consonant sounds are found throughout the mid-frequency range.

Types Of Testing

There are two kinds of testing: air conduction and bone conduction.

Air conduction testing for the right ear is marked O and D; the left ear is marked X and ÿ. Air conduction is the passage of sound by air (through the headphone, insert phone or speaker) to the ear drum and subsequently to the ossicles (tiny bones in the middle ear) and the cochlea (inner ear). This leads to stimulation of the nerve cells of the inner ear.

Bone conduction testing for the right ear is marked [ and < ; the left ear is marked ] and > When no response is obtained, this is marked ¯ When soundfield is used to test, the responses for the better ear are marked S and W. Bone conduction is the passage of sound through the bones of the skull to the inner ear. This is done through the placement of a bone vibrator behind the ear, which sends the sound directly to the inner ear through the vibration of the skull. As opposed to air conduction, this bypasses the outer and middle ear.