Any hearing loss that is present at birth or soon after is referred to as congenital. Hearing loss which occurs later in life is referred to as acquired.
The earlier a hearing loss occurs, the more significant its impact will be. Children who are born with a hearing loss have limited access to the sounds around them (including speech) from the very beginning.
Hearing loss that occurs before a child develops speech and language skills is referred to as prelingual. Hearing loss that occurs after a child develops speech and language skills is known as postlingual.
The effects of a prelingual hearing loss are usually much more significant than a postlingual hearing loss. The challenge faced by a young child with a prelingual hearing loss is to develop normal spoken language skills. The challenge faced by a child with a postlingual hearing loss is to learn to manage their hearing loss in order to minimise its impact on their daily life.
When a hearing loss occurs because the sound cannot travel freely down the outer ear and through the middle ear, it is referred to as a conductive hearing loss. A child with a middle ear infection may have a conductive hearing loss. If the conductive hearing loss is a result of illness or infection, then it is not permanent.
Hearing loss which is caused by the sound not being converted into electrical signals within the inner ear, or not being transmitted along the auditory nerve to the brain is referred to as sensorineural hearing loss. This hearing loss is permanent.
Some children experience both conductive and sensorineural hearing loss, and this is referred to as a mixed hearing loss.
When hearing loss is measured, it will be described as mild, moderate, severe, profound or a combination of these. For example, if someone has a moderate hearing loss in the low frequencies and a profound hearing loss in the high frequencies, this hearing loss would be described as moderate to profound.
When a hearing loss is plotted on an audiogram, it may appear flat, i.e. the hearing loss is much the same across the frequencies (seen on the diagram below), or it may be sloping, e.g. the hearing loss is much more severe in the higher frequencies than it is in the lower frequencies.
Flat hearing losses are usually much easier to fit with a hearing aid. Sloping hearing losses may mean that children will miss a lot of the high frequency sounds such as ‘s’ and ‘sh’ and they are often more difficult to fit with a hearing aid.
When there is a hearing loss in both ears, this is referred to as bilateral hearing loss. If hearing is normal in one ear, but there is a hearing loss in the other ear, this is referred to as unilateral hearing loss.
Children with a unilateral hearing loss may have difficulty hearing well in noisy conditions and may have difficulty locating where sound is coming from. Teachers should make sure that children with a unilateral hearing loss always sit with their ‘good ear’ closer to the speaker.
When the hearing loss is very similar in both ears, this is referred to as a symmetrical loss. If the hearing loss is different in each ear, this is referred to as an asymmetrical loss. If the loss is very different in each ear, the child may experience difficulties similar to those associated with unilateral loss. Sometimes only the ‘better ear’ will be fitted with a hearing aid.
Hearing loss does not always remain the same over time. Some hearing losses, particularly conductive, may go up and down frequently. This is referred to as a fluctuating hearing loss.
Children with fluctuating conductive hearing loss may develop very poor listening skills. Some hearing losses may get worse over time. This is referred to as a deteriorating hearing loss. Children with a deteriorating hearing loss may show a decline in their speech and listening skills over time.
For more information:
Disclaimer: The information contained on this website is not intended as a substitute for independent professional advice.
