What is hearing loss?
Hearing is arguably the most important of our five senses. Our hearing enables us to communicate with others and to participate fully in the world around us. Helen Keller once said that “when you lose your vision you lose contact with things but when you lose your hearing, you lose contact with people”.
Our ability to hear well is key to our quality of life. Over the course of our lives our hearing can change and deteriorate. Hearing loss can occur gradually or suddenly but most of the time it occurs slowly over many years. Many people try to cope with their hearing loss for as long as they can. In New Zealand it takes on average seven years before people seek help. Common coping strategies that people use are:
Lip reading.
Avoiding difficult listening situations such as groups or social gatherings.
Asking people to speak up or to repeat themselves.
Research shows that untreated hearing loss can lead to auditory deprivation. This is a condition where the brain does not get enough stimulation from sound. Over time this can lead to a decline in cognitive function. Interestingly, research has shown a link between hearing loss and memory problems. One theory is that when we have a hearing loss we have to try harder to hear and this extra effort uses more of our brain’s resources. Other area’s of our brain such as memory have less resources available and start to deteriorate over time. When it comes to hearing, the “use it or lose it” philosophy is certainly true. It is much harder to get back the loss of cognitive function than it is to give the brain the sound stimulation it needs in the first place.
What are the symptoms of Hearing Loss?
Hearing loss can occur at any age. It occurs when there is a breakdown somewhere along the hearing pathway making it difficult to interpret sound. For some people the process can occur quickly but for many it is a gradual insidious process. In the early stages many people are not even aware that they have a hearing loss
Common early signs are:
Asking people to repeat themselves.
Difficulty understanding speech in a group situation such as a restaurant or meeting.
Difficulty following the conversation if there are more than two people talking.
Thinking that everyone is mumbling.
Having difficulty hearing women or children clearly.
Having the television or radio turned up louder than others prefer.
Responding inappropriately in conversation with others or when answering questions.
Tinnitus (noises in your ears).
Reading lips or watching faces intently when people talk to you.
The early stages of hearing loss can be tiring because of the extra effort required to hear. It is common to feel:
Stressed from straining to hear what others are saying.
Annoyed at other people for not making more effort when they talk to you.
Embarrassed when you meet new people because you mishear their name.
A loss of confidence because you might get things wrong.
Social isolation is common with hearing loss.
It takes less effort to withdraw from social situations than to try to participate.
What are the types of Hearing Loss?
There are several main causes of hearing loss. These can be divided into two basic types, called conductive and sensorineural hearing loss. A third type, called a mixed hearing loss is a combination of the other two types. A full diagnostic hearing test performed by an Audiologist is needed to determine whether the hearing loss is Conductive, Sensorineural or Mixed.
Conductive hearing loss
Conductive hearing loss is caused by a problem with the transmission of sound from the outer to the inner ear. Sometimes conductive hearing loss can be treated medically or surgically. Possible causes include:
Ear infections (otitis media)
Wax blockage.
Perforated eardrum from injury or infection.
Damage to the middle ear bones (ossicles).
Otosclerosis (a condition where the ossicles become immobile).
Sensorineural hearing loss
Sensorineural hearing loss is caused by damage to the hair cells in the inner ear and/or to the nerve pathway from the inner ear to the brain. The two most common causes of sensorineural hearing loss are:
The Aging Process.
Excessive Noise Exposure.
Other possible causes of sensorineural hearing loss are:
Head Trauma
Viral Infection
Ototoxic medication (Drugs that can damage the hair cells of the inner ear)
Menieres disease
Tumours
Infection
Stroke
Medical conditions such as diabetes, and high blood pressure.
Hearing loss can be congenital (occurs before or just after birth) or acquired (occurs at a later stage due to other factors).
Age related hearing loss (Presbycusis)
Just as our bodies get older so do our ears, and consequently our hearing can diminish over time. As we age there is a natural deterioration of the hair cells within the inner ear. The function of the hearing nerve also diminishes resulting in a loss of hearing clarity. For some people this process can occur quickly but for many it is a gradual, insidious process.
Noise induced hearing loss
Exposure to excessive noise is one of the leading causes of hearing loss. Unsafe levels of noise can cause irreparable damage to the inner ear. When a person is either exposed to very loud sound for a prolonged period of time or when a person is exposed to reasonably loud sound for extended periods of time, hearing loss can occur. Hearing loss which occurs through the ageing process or through excessive noise exposure is a permanent and irreversible condition. This is because unlike other parts of our body which have the ability to heal themselves, the hair cells in the inner ear cannot regenerate. This means that once your hearing is damaged or impaired it cannot be restored without the use of hearing aids.
However, unlike age related hearing loss, noise-induced hearing loss is preventable with the use of good ear protection and by limiting exposure to damaging noise levels. Prevention is always better than cure. The risk of damage due to loud noise depends primarily on how loud the sound is, how long you are exposed to it and how many times you are exposed to it. The louder the sound, the less time you can be exposed to it before damage occurs. Loudness is measured in decibels. Occupational Health and Safety Standards have taken these factors into account when putting together their guidelines for safe exposure times. Essentially, anyone exposed to sounds 85 dB (A) or greater for 8 hours or more a day is at risk of damaging their hearing and is required by law to wear ear protection.