What is age-related hearing loss?

Age-related hearing loss, medically known as presbycusis, is the partial or complete loss of hearing that develops with age. It is a common condition, with up to one in three people over the age of 65 affected by varying degrees of hearing loss.

How does hearing work?

The ear is composed of three distinct parts - the outer ear, middle ear and inner ear. Sound moves from the outer ear to the inner ear, and is converted along the way to electrical signals that the brain can interpret.

The outer ear collects soundwaves and directs them down the ear canal towards the eardrum. The eardrum is a thin piece of skin, about 10mm in diameter, located between the ear canal and the middle ear. The eardrum is very sensitive; slight changes in air pressure (such as soundwaves) cause it to vibrate.

On the other side of the eardrum, in the middle ear, is an arrangement of three tiny bones called ossicles. They are located between the eardrum and the opening of the inner ear. When the eardrum vibrates, it moves the ossicles. The ossicles' motion amplifies the vibration and transfers it to the fluid within the cochlea.

The cochlea is part of the inner ear. Its surface is covered with tiny, delicate hairs. The fluid moves the hairs, whose movement is converted into electrical signals that are sent to the auditory nerve of the brain. Different sounds cause unique vibrations of these hairs, sending specific electrical signals to the brain, where the signals are interpreted as speech, music and noise.

The anatomy of the ear. 

Cochlea

The spiral-shaped cavity of the inner ear, responsible for converting soundwaves into nerve impulses that the brain recognises as sound.

Ossicles

Three very small bones that form a chain just behind the eardrum, which transmits sound from the outer to the inner ear.

Eardrum

The thin membrane between the external and middle ear that converts soundwaves into vibrations, which are then transmitted to the inner ear.

Causes

Age-related hearing loss can have numerous causes. In most cases, the nerve cells in the inner ear that convey sound from the ear to the brain accumulate damage over time. Once this damage to the nerve cells reaches a certain level, hearing loss becomes apparent.

Another cause for age-related hearing loss can be years of exposure to loud noise, which causes a condition called noise-induced hearing loss.

Other causes of hearing loss may relate to poor blood circulation, hardening of blood vessels that supply cells within the inner ear, or certain medications.

Circulation

Moving in a circular route, as in blood through the body.

Nerve cells

The basic cell of the nervous system. A specialised cell that generates and transmits nerve impulses.

Risk factors

Factors that can contribute to the progression of age-related hearing loss can include:

  • Excessive exposure to noises;
  • Earwax build-up;
  • Genetics - some people are naturally more prone to hearing loss;
  • Smoking;
  • Having poorly-controlled diabetes;
  • Head injury, and;
  • Recurrent ear infections, such as middle ear infections.

Diabetes

A metabolic disorder that is caused by problems with insulin secretion and regulation and which is characterised by high blood sugar levels. Also known as diabetes mellitus.

Genetics

Related to genes, the body's units of inheritance or origin.

Signs and symptoms

Symptoms of age-related hearing loss may include:

  • Difficulty following conversations, either when it is quiet or in the presence of background noise;
  • Having trouble distinguishing between high-pitched and low-pitched sounds;
  • Thinking that others are mumbling, and;
  • Ringing in the ears, known as tinnitus - this can appear and disappear at regular intervals, stop completely or become permanent.

Methods for diagnosis

Age-related hearing loss may be diagnosed from the following:

Physical examination

Your doctor will perform a detailed physical exam, with particular attention paid to the ear. They will also ask you questions about your hearing, your life and work, and any medical conditions you may have or medications you are taking. They will assess your level of hearing by covering one ear at a time. They may use a tuning fork, which is a metal instrument that produces a sound when struck. The fork can be tapped and held in the air on each side of your head to test your ability to hear sounds travelling in the air (air conduction). It is then tapped and placed on your head (behind the ear), to test how sound is conducted through bone (bone conduction).

An otoscope can also be used to enable a detailed view of the outer ear and eardrum for presence of:

  • Blockage caused by earwax;
  • A bulging eardrum, which can suggest a middle ear infection;
  • Fluid behind the eardrum, or;
  • A collapsed eardrum.

Hearing test (audiometry)

An audiologist uses an audiometer to accurately assess the degree of hearing loss. During this test, the audiometer produces different sounds at various frequencies and volumes that you listen to and respond to.

Otoscope

An instrument used to examine the external ear and the eardrum.

Eardrum

The thin membrane between the external and middle ear that converts soundwaves into vibrations, which are then transmitted to the inner ear.

Types of treatment

Treatment of age-related hearing loss depends on the underlying causes. Where correctable causes of hearing loss are not present, there are various devices available to help support people with hearing loss:

  • Alert systems for doorbells, smoke detectors and alarms that send visual cues or vibrations;
  • Telephone amplifiers that increase the volume of the voice being listened to;
  • Hearing aids;
  • A cochlear implant for cases of severe hearing loss, and;
  • Television and radio listening systems, such as wireless headphones, neck loops or ear hooks that enable listening at the desired volume and at reduced background noise.

When talking to someone with hearing loss, it may be helpful to:

  • Face the person and stand close to them;
  • Speak more slowly;
  • Be patient;
  • Try to make sure only one person talks at a time, and;
  • Include hand and body gestures to aid communication.

Potential complications

Potential complications that can develop as a result of age-related hearing loss include the following:

  • Anxiety - not hearing properly in your surroundings may cause feelings of discomfort that can lead to anxiety;
  • Physical danger - our sense of hearing alerts us to what is happening around us. People with hearing loss are less aware of dangers such as traffic noises, alarms going off, etc.;
  • A sense of isolation - hearing loss may prevent you from leaving home or avoiding using the telephone, thereby reducing your interaction with others, and;
  • Depression - this may be a result of ongoing isolation and anxiety.

Anxiety

A feeling of tension, nervousness and dread about future events. It can trigger physical symptoms such as a rapid pulse or breathing difficulties.

Prognosis

Most people who develop age-related hearing loss manage well in normal situations and do not require any significant treatment. But as their hearing loss worsens, they may benefit from using a hearing aid or other assistive devices, such as the telephone and smoke detectors, to help them maintain their lifestyle and stay safe.

Prevention

Age-related hearing loss is not preventable. However, there are several ways of slowing its progression to severe hearing loss, such as:

  • Avoiding or reducing exposure to loud noises;
  • Not smoking;
  • Maintaining good health and a healthy weight;
  • Controlling blood sugar levels if you have diabetes;
  • Wearing ear protection when in loud environments, and;
  • Having your ears checked regularly by your doctor.

 

Diabetes

A metabolic disorder that is caused by problems with insulin secretion and regulation and which is characterised by high blood sugar levels. Also known as diabetes mellitus.