Understanding Hearing Loss

How We Hear

The ear is a remarkably complex sound system. A good understanding of how we hear is beneficial for understanding hearing loss.

Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013.

Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013.

Outer Ear (External Ear)

Your outer ear gathers sound waves from the environment. The shape of your outer ear helps to emphasise information important for speech understanding. Your outer ear then transfers this information down your ear canal to your middle ear for further processing.

The Middle Ear

Your middle ear consists of the tympanic membrane (ear-drum), Eustachian tube and 3 of the smallest bones in the body, the ossicles. These work together to increase the intensity of sound for optimal processing in the inner ear (cochlea).

The middle ear is responsible for pressure equalisation – i.e. in order to hear best we need to have equal pressure either side of the ear-drum. In young children (up to approximately 7 years of age) the Eustachian tube is more horizontal than in adults and does not drain any fluid that may build-up in the middle ear efficiently. This is why children are more susceptible to middle ear dysfunction (e.g. often referred to as glue ear).

Middle ear pathology can also occur in adults.

Hearing loss associated with middle ear problems is referred to as a Conductive Hearing Loss. Some middle ear pathologies are able to be medically managed via surgery, others not. All Ears Audiology works closely with Ear, Nose and Throat specialists to ensure the best outcome for all clients.

The Inner Ear (Cochlea)

Your inner ear (cochlea) analyses and interprets the sounds received from your middle ear and then converts this sound to a bio-electrical signal to be transmitted via your auditory nerve to your brain. Your brain then turns the signal into sounds or speech that you can recognise and understand.

The inner ear also includes our vestibular system which plays an important role in our balance.

Hearing loss associated with inner ear problems is referred to as a Sensorineural Hearing Loss. This is a permanent type of hearing loss often requiring both medical and audiological management.

People can also present with a Mixed Hearing Loss. In these cases there is both middle ear pathology and an inner ear (cochlea) problem. Mixed hearing losses often require both medical and audiological management.

Why Are Two Ears Better Than One?

Binaural hearing refers to the way in which our two ears work well together. This is important for localising sounds and for listening in background noise. Our brain is able to compare and contrast information received from each ear separately to determine what sounds are important to listen to, and what sounds can be ignored. When one or both ears are not working well, you may find it harder to hear speech clearly, particularly in background noise. This is why it is important to always manage hearing loss in both ears.

Why are two ears better than one

Why Does Hearing Deteriorate With Age?

The most common hearing loss is an age-related hearing loss known as Presbycusis (from Greek presbys “elder” + akousis “hearing).  From approximately 50 years of age, the tiny hair cells in the inner ear (the cochlea) start to deteriorate from use. The central auditory pathway (i.e. the auditory nerve to our brain) also starts to become less efficient at processing auditory information. This is a slow and gradual process which is why you may not be aware it is happening.

However, for many people with hearing loss, family members have typically raised concerns prior to a diagnosis. This may include family members frequently having to repeat themselves and asking for the TV or radio to be turned down. You may also find that people around you seem to be mumbling and that speech is difficult to understand, especially in noisy environments. This is another sign that you hearing is deteriorating. People with hearing loss often report feeling isolated, especially when at a social gathering.

Currently there is no prevention for an age related hearing loss.

Good News: The phrase “Use it or Lose it” is well applied to the early identification and management of hearing loss. Research has shown that the quicker people identify and manage their hearing loss the better the outcome. The longer a hearing problem is ignored the more difficult it becomes to adapt to hearing again (e.g. using hearing aids).  The sooner you start your journey to hearing well again the better the brain adapts and wants to hear sounds the way it used to.

The most effective way to stimulate these pathways is with the use of a hearing device. This may include the use of hearing aids and assistive listening devices.

It is important to know you are not alone and there are many solutions to assist you with hearing better.

When Can Hearing Loss Occur?

  • At birth (congenital)
  • With age (1 in 4 people over 50 years of age have hearing loss)
  • Due to a history of middle ear infections
  • During pregnancy or menopause
  • With damage from noise exposure (e.g. work or hobbies)
  • Trauma
  • From the use of ototoxic drugs, medication, chemotherapy
  • Medical conditions (e.g. Diabetes, Meniere’s disease, Otosclerosis etc.)

Noise Exposure

Exposure to loud noises through work or leisure activities can cause permanent damage to your hearing. Hearing loss associated with noise may be the result of an intense but brief period of high-level noise exposure, or from repeated exposure to high-level sounds. The exact damage associated with intense noise exposure is still debated, however what we do know is that noise induced hearing loss primarily affects the higher frequencies having a significant impact on one’s ability to understand speech, particular in background noise.

Noise induced hearing loss is commonly associated with tinnitus (e.g. ringing in the ears). In fact, tinnitus is usually the main reason for people presenting with concerns in this area (please see tinnitus information).

Noise induced hearing loss has been long recognised as a cause of significant hearing loss. Many employers have now implemented hearing protection policies regarding the use of hearing protection and ensure staff have their hearing assessed prior to starting and regularly following. If you have worked in a noisy industry and have a hearing loss you may be entitled to compensation. The staff at All Ears Audiology are able to provide further information regarding worker’s compensation in this area.

Hearing Protection

It is never too late to use ear protection and you may consider custom made earplugs or purchasing sound attenuating earmuffs.  It is important to protect your hearing, even if you have already shown damage through noise exposure.

At All Ears Audiology we are able to make custom earplugs, musician plugs and/or advise you regarding sound attenuating earmuffs.

Tinnitus

Tinnitus refers to noises that can be heard in one or both ears in the absence of external sound, often experienced as ringing or buzzing although may also be described as loud noises, bells chiming, cicadas, rushing or roaring sounds and in some cases even singing.

Tinnitus can be intermittent or permanently present and is often more prominent in quiet environments.

Tinnitus can occur, but is not specific to, exposure to loud noise through work or leisure activities, medication, stress or illness, lack of sleep, medical conditions such as Meniere’s disease, and permanent damage to the hair cells in the cochlear (e.g. with age or noise exposure).

While there is no cure for tinnitus, the most effective treatment involves retraining the brain to not pay attention to the sound. Some people have also found the fitting of a hearing aid beneficial, while others need further counselling and sound therapy to assist. For some people the pitch of the sound (frequency) can be determined and a tinnitus masker used.

A hearing assessment, along with medical advice, will help to determine the cause of tinnitus and assist in determining the most appropriate form of management required.

 

If you, or somebody you know, is experiencing hearing difficulties the team at
All Ears Audiology would be delighted to meet you. Please call 8120 2110.

All Ears incorporates Little Ears AudiologyGo to Little Ears