This article is on Audiograms or hearing tests which are commonly used in ENT. This resource is open to everyone. Patients, Medical Students and Doctors may find this useful. The additional information shown in grey boxes provides more technical information intended for Medical Practitioners.

In order to understand this topic better you may also wish to read these other articles on related topics:

Structure and function of the ear

What is an Audiogram?

An audiogram is also known as a hearing test. It is completed by Audiologists who work closely with the ENT team. The test is painless and takes roughly 20-30 minutes to complete.

Patients are seated in a soundproof room with headphones. Various sounds are played at different volumes to determine the level of hearing. A pressure test on the ear drum (tympanometry) and speech discrimination may also be completed as part of the hearing assessment.

Combining all the information, the hearing test is a useful tool to determine the degree of hearing loss, the type of hearing loss and narrow down the possible causes.

Completing a hearing test requires a level of understanding and cooperation from the patient as patients need to let the Audiologist know when a sound is heard. This creates some challenges for children who require a hearing test. The audiologists have different methods to complete hearing tests for children, this may include visual aids or play assisted testing.

 

When is an Audiogram needed?

Audiograms are required for a number of reasons. These include:

  • Sudden onset hearing loss
  • Gradual hearing loss with difficulty in social settings
  • Adjustment of hearing aids
  • Trauma to the ear/ear drum
  • Speech or developmental delay in children
  • Other symptoms: dizziness or ringing in the ear (tinnitus)

 

What are the symbols and how do I interpret the report?

Interpreting an audiogram can be very complex. Your audiologist or ENT specialist will be the best people to explain the results to you. Depending on the result and the cause of hearing loss, your ENT doctor may request other tests or scans. They will also be able to let you the options for treatment.

 

The standard audiogram report used at Waikato Hospital

 

Common questions you may be asked

  1. Have you noticed any hearing loss?
  2. When did you notice your hearing loss?
  3. Which is the worse ear?
  4. Does the hearing loss fluctuate?
  5. Have you been exposed to loud noise in the past?
  6. Have you had any injuries or surgeries to your ear?
  7. Is there anyone in your family with hearing loss?
  8. Is there any other symptoms? Dizziness, ringing in ears, pain or discharge from ear canal.

 

Types of hearing loss

Conductive hearing loss

  • This type of hearing loss is due to a problem with sound transmission from the outside to the inner ear (cochlea)
  • The issue could arise anywhere from the ear, ear canal, ear drum or the 3 small ear bones (malleus, incus, stapes)
  • In children, glue ear or fluid behind the ear drum is the most common cause of conductive hearing loss.

Sensorineural hearing loss (SNHL)

  • This type of hearing loss is due to a problem with sound processing from the inner ear (cochlear) to the brain.
  • The issue could arise from the inner ear, the hearing nerve or the brain itself.
  • This type of hearing loss is usually symmetrical in both ears. When the loss is different between the ears, your doctor may advise further investigation or scans.
  • It is common and normal to have gradual SNHL as you age
  • Children born with SNHL should be picked up at the newborn hearing screen. This is critical to ensure development of speech and communication.

Mixed hearing loss

  • This type of hearing loss is contributed by both conductive and sensorineural components.

 

Levels of hearing loss

1) Mild (20-40dB) – Usually no issues with normal conversation in a quiet environment but may struggle with a noisy background.
2) Moderate (41-60dB) – Will struggle with most normal conversation.
3) Severe (61-90dB) – Will be unable to hear most conversation even with raised volume. Telephone ringtones may also be missed.
4) Profound (>90dB) – Unable to hear speech sounds

 

Further reading:

1. https://www.healthline.com/health/audiogram
2. https://www.hopkinsmedicine.org/health/conditions-and-diseases/hearing-loss/understanding-your-audiogram

 

References:

1. Davies R. Audiometry and other hearing tests. Handbook of Clinical Neurology. 2016. 137:11 157-76
2. Rose E. Audiology. Australian Family Physician. 2011.

 

Author + Affiliation: Dr. Johnny Wu, ENT Registrar, Waikato Hospital

Date of Publication + Review: 28 February 2022

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