1. Module: Preprogrammed hearing aids
  2. Lesson 1: Introduction to hearing aids
  3. Topic 3 of 5

Measuring hearing loss

Topic Progress:

Instruction

Read on to learn about how hearing loss is measured and the different grades of hearing loss.

How to measure hearing loss

Hearing loss is measured using an audiometer.

An audiometer measures sound volume in decibels (dB).

Audiometer machine

Audiometer app on tablet

Audiometer app on smartphone

Hearing test (audiometry)

Tests how well a person hears sounds. This includes how well a person can hear different types of sound and how loud or quiet sounds are.

Instruction

In this module audiometry is referred to as a hearing test.

A person wears headphones. The right headphone is red, and the left headphone is blue. The person has their hand raised. A health worker stands behind the person holding a tablet audiometer.

Audiogram

The hearing test results are shown in an audiogram.

An audiogram shows the quietest sound that a person can hear (hearing threshold) at different frequencies of sound.

  • Frequency (hertz) is shown with low frequency sounds on the left and high frequency on the right
  • Loudness (decibels) is shown with quiet sounds at the top and loud sounds at the bottom.

An audiogram graph of a person’s hearing test thresholds. Right ear (marked by red circles) and left ear (marked by blue crosses). The vertical axis shows sound level in decibels (dB) from 0 dB at the top down to the loudest level at 140 dB. Frequencies are on the horizontal axis from 125 Hz to 8000 Hz from left to right.

Results for each ear are shown differently:

  • Red or circles for right ear
  • Blue or crosses for left ear.

Results may be in two separate audiograms for right and left or in one audiogram.

Different types of sounds (frequency)

Different types of sound (frequency) are measured in hertz (Hz).

  • Examples of high frequency sounds include a whistle and birds singing
  • Examples of low frequency sounds are a drum and chainsaw.

Question

Look at the pictures on the audiogram.

An audiogram graph showing different frequencies on the horizontal axis from the lowest at 125 Hz to highest at 8000 Hz (from left to right). The vertical axis shows sound level in decibels (dB) from 0 dB at the top to loudest at 140 dB at the bottom. Icons on the table show the level and type of sound. For example: • A bird chirping is at 5 dB and 8000 Hz • Tree leaves moving in the wind is at 15 dB and 2000 Hz • A person whispering is at 30 dB and 4000 Hz • A verbal conversation is at 60 dB at 2000 Hz • A chainsaw is at 100 dB at 250 Hz • A motorcycle is at 100dB at 4000 Hz • An airplane engine is at 120 dB at 4000 Hz • A firework exploding is at 130 dB at 125 Hz.

Which picture shows a high frequency and loud sound?




Click to check answer

Motorcycle is correct!

  • A motorcycle is a high frequency loud sound
  • A chainsaw is a low frequency loud sound
  • Falling leaves is a medium frequency quiet sound
  • Birds singing is a high frequency quiet sound.

‘Speech banana’

An audiogram graph showing a grey area in a shape of a banana between the area of 20 dB to 65 dB covering 125 Hz to 8000 Hz. This shows which letters are heard in a specific frequency. • Most vowels are at low frequencies (125 Hz to 500 Hz) • Sounds like “p”, “h”, “g”, “sh” and “ch” are middle frequencies (1000 Hz to 2000 Hz) • Letters like “f”, “s”, and “th” are high frequencies (4000 Hz to 8000 Hz).

The banana shaped area on the audiogram shows speech sounds at conversation level.

The sounds in our speech have low, medium and high frequency sounds.

If a person has hearing loss, they may hear some speech sounds and not others. This makes it harder to understand what a person is saying.

As hearing loss increases it becomes more difficult to hear conversations in a normal speaking voice.

Grades of hearing loss

An audiogram graph showing grade of hearing loss on the right (bottom to top): • Profound hearing loss, 80 dB and above • Severe hearing loss, 65-79 dB • Moderately severe hearing loss 50-64 dB • Moderate hearing loss, 35-49 dB • Mild hearing loss, 20-34 dB • Normal hearing, less than 20 dB.

People with hearing loss cannot hear as well as people with normal hearing.

The results of a hearing test can be graded to six different levels for each ear. The grades are based on average hearing thresholds for each ear:

  1. Normal hearing
  2. Mild hearing loss
  3. Moderate hearing loss
  4. Moderately severe hearing loss
  5. Severe hearing loss
  6. Profound hearing loss

Remember John?

John retired after working in a noisy factory for 34 years.

He has a hearing test at his local health service. The health worker shows John his hearing test results and explains he has severe hearing loss in both ears.

The health worker explains that John may find it difficult to hear conversations.

Instruction

Learn how to calculate average hearing thresholds in Lesson two.

  1. Module: Preprogrammed hearing aids
  2. Lesson 1: Introduction to hearing aids
  3. Topic 3 of 5