Different Types of Audiograms

What are Audiograms

Audiograms are a graph that use an x- and y-axis to pinpoint results to a hearing screening. The graph allows the audiologist to see the results of a pure-tone test. This screening shows the type of hearing loss, the configuration or what pattern the hearing loss makes, and the degree of the loss.[2]

Symbols on an Audiogram

Masked vs. Unmasked

An unmasked hearing test is when the client only hears the beeps, speech, or other sounds when being screened. This means that between beeps the client does not hear anything else except for the occasional conversations from the audiologist leading the testing. A masked screening is when there is background noise playing through the headset the client is wearing. This "masks" the beeps or speech that the client is listening for. This technique helps test for speech-in-noise recognition.

Right Ear Symbols Compared to the Left Ear Symbols

The right ear uses symbols such as the open circle when unmasking and the triangle when masking in an air conduction test. When the audiologist beings to do bone conduction testing, the right ear uses symbols such as the less than sign (<) for unmasked and a bracket ([) for masked.

The left ear uses the symbol of an 'x' for unmasked and a square for masked air conduction screenings. Once the bone conduction testing begins, the left ear uses symbols such as the greater than symbol (>) for unmasked and a bracket (]) for masked testing.

No Response Symbol

In the picture above, the no response symbol is represented using an arrow that points downward. For the right ear, the arrow points to the left and vice versa for the left ear. This is used for when a client has no response to a tone that was being played at multiple frequencies at different decibels. That means that their hearing threshold is less than what the audiologist is able to test for.

Sound-Field Testing

A sound-field test is where the client does not wear headphones and instead is placed in a sound booth with speakers that plays the tones. This type of testing can also be used to help with hearing aids and their performance. This is usually used on younger children but adults can participate in it if they choose.[3] This testing is represented with the letter 's', which is placed on the audiogram.

In the image above is a normal audiogram. This audiogram also only shows an air conduction screening. Both the left and right ear fall within the normal hearing range.

The image above shows results of an air and bone conduction. It is shown that the air conduction results in the left ear is abnormal but the bone conduction is within normal hearing range.

Different Types of Hearing Loss and What They Look Like

Conductive Hearing Loss

"Hearing loss caused by something that stops sounds from getting through the outer or middle ear. This type of hearing loss can often be treated with medicine or surgery."[4] This hearing loss can be caused by built up wax or a perforation in the tympanic membrane. The image shown to the left pictures an air conductive hearing loss in the right ear and normal air conductive results in the left ear.

Sensorineural Hearing Loss

"Hearing loss that occurs when there is a problem in the way the inner ear or hearing nerve works."[5] Pictured to the right is an example of a noise induced sensorineural hearing loss. There is a direct relationship between both the air conduction testing and the bone conduction testing. This shows that in the higher frequencies this client has a harder time hearing. Their hearing starts normal and falls into the moderately-severe hearing range.

Mixed Hearing Loss

"Hearing loss that includes both a conductive and a sensorineural hearing loss."[6] This means that the client can have an obstruction of the ear canal, articulation problems of the middle ear bones, or some type of issue within the cochlea itself. In this audiogram, the space between the air conduction and bone conduction results is greater than 10-15 dB, which suggests a mixed hearing loss. This client has a mixed hearing loss that is a moderate-to-profound hearing loss.

Severity of Hearing Loss

"Speech Banana"

The highlighted yellow portion of this audiogram shows the "speech banana." This shape shows where specific speech sounds fall within human hearing. Also on this audiogram is also other examples of sounds and where they fall within human hearing. For example, for someone to be able to hear a piano, they would need to be able to hear sounds around 1000 Hz at a 80 dB hearing level. To hear human talking, an individual needs to be able to hear sounds around 1000 Hz at 40 dB, this is for normal speech level.

On the right side of this graph it shows ranges of where hearing levels are from normal hearing to profound hearing loss. Below there is a more detailed graph.

Ranges of Hearing Loss

As shown in the picture to the right, there are many ranges to hearing loss. From normal to profound, hearing losses fall into many different assortments and ranges. Most individuals fall into the normal hearing range but as humans age, their hearing can start to teeter off, falling into ranges like a slight, mild, moderate, moderately severe, severe, and even profound. Individuals who have a profound hearing loss are said to be deaf.

As children develop, the onset of their hearing loss will determine what category they fall into. If a child is identified as having a hearing loss before they develop speech, they are known to be prelingual. If their hearing loss develops while they are developing language (after age five), they are identified as perilingual. When a hearing loss becomes prevalent after the age of five, their development is known as postlingual, or after language. Lastly, if a child develops as normal, with their hearing and after schooling their hearing loss becomes an issue, they are identified as deafened.

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