How Do We Hear?

Soundwaves enter our outer ear and travel along the ear canal to the eardrum, causing it to vibrate. These vibrations are amplified by three small bones in the middle ear and sent to the cochlea, a snail-shaped structure filled with fluid.

As the fluid in the cochlea moves, 25,000 nerve endings are set in motion transforming the vibrations into electrical impulses for our brain to interpret.

The sounds we hear are measured by Audiologists in terms of decibels (intensity) and frequency (pitch). The human hearing range typically falls between 0 to 140 decibels. People should avoid prolonged exposure to sounds above 80 decibels, as this may damage hearing.

Mild hearing loss exists when an individual struggles to hear sounds in the 30 to 40 decibel range, with moderate hearing loss affecting sounds in the 50 to 70 decibel range.

Frequency is represented by Hertz, with low numbers representing low sounds and high numbers representing high sounds. Everyday sounds range from 250 to 6,000 Hertz, although the human ear can detect sounds in the 20 to 20,000 Hertz range.

People typically miss high frequency sounds more often than low frequency sounds when they first develop hearing loss.

Presbycusis: Age Related Hearing Loss

One in three people over 65 have hearing loss, although they may not be aware of it at first due to the gradual change. This loss typically affects high-frequency noises first, such as a ringing phone or alarm tone.

The most common symptoms of age-related hearing loss include:

• High-pitches sounds, such as 's' or 'th' become hard to distinguish.
• Conversations are hard to follow, particularly when there is background noise.
• Other people's speech can seem mumbled or slurred, with men's voices easier to understand than women's.
• The onset of Tinnitus in one or both ears (ringing in the ears).