Definitions of hearing loss

Understanding the terminology involved with hearing loss helps take you one step closer to understanding the condition itself.

Measuring of Sound

To better understand the levels of sound people with hearing loss can hear it is best to know how sound is measured:

Decibels are the units used to calculate the strength of sound. The human ear is extremely sensitive and is able to pick up very low and loud decibel sounds. To give you an idea of the level of decibels for different sounds here are some examples:

Close to total silence – 0 decibels
Regular breathing – 10 decibels
Average home – 50 decibels
Conversational speech – 60 decibels
Pavement next to busy road – 80 decibels
Car horn- 110 decibels
Rock concert- 120 decibels
Gunshot- 140 decibels

A sound above 85 decibels can cause damage to your hearing, the extent of which being dependant on the power of the sound and duration of exposure. 120 decibels is the threshold of discomfort, and 140 decibels the threshold of pain.

Levels of Hearing Loss

There are four main levels of hearing loss, each of which are categorised according to the quietest sound that can be heard:

Mild Hearing Loss – People with mild hearing loss often have difficulty following speech, particularly in situations where it is noisy. The lowest sound people with this form of hearing loss can perceive is 25 to 39 decibels.

Moderate Hearing Loss – People with moderate hearing loss have difficulty following speech, even when they are wearing a hearing aid. The lowest sound people with this form of hearing loss can perceive is 40 to 69 decibels.

Severe Hearing Loss - People with severe hearing loss are likely to rely on lipreading, even when they are wearing a hearing aid. The lowest sound people with this form of hearing loss can perceive is 70 to 94 decibels.

Profound Hearing Loss – People with profound hearing loss are prone to using lipreading, but are likely to use sign language as their first or preferred language. The lowest sound people with this form of hearing loss can perceive is 95 decibels or more.

Language

There are several methods of communication used by deaf and hard of hearing people. They are as follows:

Sign Language – Sign language, instead of using sounds, uses visual signs made with the hands to convey meaning, and also involves the use of the arms, posture of the body, and also facial expressions. As with speech there is no universal sign language, British Sign Language (BSL) being testament to that.

Lipreading – Lipreading is a way of understanding speech by visually interpreting the movements of another’s lips, tongue, and face. Other visual information such as context and body language are also important, as well as the monitoring of syllables and pace of speech. This form of communication requires great concentration and can be difficult if people talk fast or cover their mouths.

Lipspeakers – Lipspeakers are skilled professionals who are trained to be easy to lipread. People with hearing problems can hire lipreaders for work, legal matters, medical matters, and other settings. The lipreader mutely repeats words said by the speaker, reproducing the necessary rhythm and phrasing of words. Body language and facial expressions are also important in order to convey meaning. In some cases, lipspeakers are able to use sign language for words that are difficult to lipread.

Hearing Aid – Hearing aids are an apparatus worn in or behind the ear to help deaf or hard of hearing people to make out sounds more clearly. Hearing aids work by intensifying sounds, and can vary in size and strength. There are two main types of hearing aids: Analogue Hearing Aids, that amplify all sounds; and Digital Hearing Aids, that boost the sounds of speech, but reduce other sounds you do not want to hear.