Deafblindness

Deafblindness

There may be as many as 250,000 people who have problems with both vision and hearing due to advancing age

Deafblindness is a term that describes a number of conditions involving both visual and hearing impairment.

Deafblindness is also sometimes called dual-sensory impairment or multi-sensory impairment. However, throughout this article, the term deafblindness will be used.

Deafblindness covers a wide range of unique conditions. Some people may retain some vision and hearing, others may have a total loss of vision and hearing, and many will have a combination of the two, such as total deafness, plus some loss of vision.

Types of deafblindness

It is difficult to estimate the number of people who are deafblind in the UK. There are 23,000 people who are known to have a medical condition that has caused deafblindness, but there may be as many as 250,000 people who have problems with both vision and hearing due to advancing age.

There are two main types of deafblindness:

  • Congenital deafblindness: where somebody is born with both visual and hearing impairment.
  • Acquired deafblindness: where somebody loses some or all of their hearing and sight at some stage in their life. In the case of acquired deafblindness, it is rare for both impairments to occur at the same time. For example, with a rare genetic disorder called Usher syndrome, a person is born deaf and then begins to lose their sight later in life. Or, a person may be born blind, and start to lose their hearing as they get older.

The fact that there are so many variations of deafblindness means that there is no single treatment for the condition. Instead, a personal treatment plan will take into account each individual's needs and requirements.

Despite the profound challenges faced by those who are deafblind, many people live full and active lives. For example, the famous deafblind writer, Helen Keller, was a political activist and a leading advocate for women's rights.

Congenital deafblindness

Rubella

In the past, the leading cause of congenital deafblindness was rubella, a highly infectious viral illness, which is also known as German measles.

If a pregnant woman gets rubella, it can cause serious damage to her unborn baby, particularly to their eyes, ears and heart.

However, since routine rubella immunisation was introduced in 1988, and due to the success of the MMR (mumps, measles and rubella) vaccine, the number of babies affected by rubella has fallen dramatically. For example, there has been a 90% decrease in the levels of rubella that existed during the 1970s.

Premature birth

Problems associated with premature birth are a common cause of deafblindness. As smoking and excessive alcohol consumption are major risk factors for premature birth, you should avoid both, particularly if you are pregnant.

If you do choose to drink while pregnant, do not drink more than 1-2 units of alcohol, once or twice a week. Avoid binge drinking and getting drunk because heavy drinking is associated with low birth weight and an increased risk of serious birth defects. A unit of alcohol is equivalent to half a pint of normal strength lager, or beer, a glass of wine, or a single pub measure (25ml) of a spirit.

Genetic conditions

Some rare genetic conditions can also cause deafblindness, either at birth, or in the early years of childhood. One such condition is known as CHARGE syndrome, which is very rare, affecting about 1 in every 10,000 births.

CHARGE syndrome causes a pattern of related birth defects which affect the eyes, heart, nose, genitals, and ears, as well as restricting a child's growth.

Acquired deafblindness

Conditions that can lead to both the loss of vision and hearing are rare, but not unknown.

The most common condition that causes acquired deafblindness is a genetic condition known as Usher syndrome, which affects around 1 in every 25,000 people.

Due to faulty genes, children with Usher syndrome are born deaf and then develop a condition known as retinitis pigmentosa as they become older. Retinitis pigmentosa causes the retina – the part of the eye that responds to light, much like the film in a camera – to slowly deteriorate.

Eventually, the retina loses the ability to transmit information to the brain and blindness can then occur.

Other causes

Acquired deafblindness can often occur either as a result of two unrelated conditions that cause loss of vision and hearing, or as a result of aging.

For example, as we get older, our vision can decline as a result of the cells at centre of the retina deteriorating. This is known as age-related macular degeneration. A similar process can also happen with our hearing, as the cells within the inner ear that help transmit information to our brain, become damaged or deteriorate.

It is important to accurately diagnosis the remaining levels of sight and hearing in someone who is deafblind.

Total loss of both functions is rare, so you will want to make best use of the senses that remain. For example, if your vision is affected, equipment such as glasses or magnifiers may help.

The two types of test that are commonly used to test your vision and hearing are described below.

  • Clinical tests – these tests identify how well you can see, or hear, compared to normal levels of ability. These typically involve using standardised tests, such as the Snellen test, where you will be asked to read letters from a chart.
  • Functional tests – these tests study how you actually use your sight, or hearing. The tests use a wide range of different visual and audio stimulus, plus medical examinations, to determine your remaining levels of sight and hearing.

Diagnosing vision loss

If you start to experience problems with your vision, you should first visit an optician (a medical professional who specialises in designing corrective lenses, such as glasses or contact lenses, in order to help assist you with your vision.)

An optician will be able to run some tests to see how well your vision compares to normal, and will also be able to detect any eye conditions, such as glaucoma, or cataracts.

If a problem is suspected and it cannot be treated using corrective lenses, you will be referred to see an ophthalmologist (a doctor who specialises in conditions of the eye). They will run a series of tests and examinations to assess your sight, and investigate any underlying conditions that may have caused a loss of vision.

Diagnosing hearing loss

If you start to experience problems with your hearing, you should first visit your GP. They will be able to examine your ear for wax, infection, or other causes of temporary hearing loss, and treat them accordingly.

If the cause of your hearing loss cannot be established, it is likely that you will be referred to the ear, nose and throat (ENT) department of your local hospital for further assessment.

There are a series of tests that can be run to assess your hearing, such as an audiometry test, which uses different sound frequencies, and volumes, to determine what you are capable of hearing.

Hearing loss

Some people who are deafblind will experience a sudden and total loss of hearing, which can occur as a result of infection, or injury. Others will experience a gradual deterioration of function.

People with hearing loss may experience the following:

  • speech and other noises sound muffled and indistinct,
  • an inability to understand conservation when there is background noise,
  • needing to turn up the volume on the television, or radio, and
  • asking others to speak more loudly, clearly, or slowly.

Loss of vision

Some conditions, such as diabetic retinopathy, can cause sudden blindness. Diabetic retinopathy is a condition that is related to diabetes, where excess levels of glucose in the blood cause damage to the blood vessels in the eyes.

Other conditions, such as cataracts (a condition where the lenses of the eye become clouded), and glaucoma (a condition where changes in pressure inside the eye causes damage to the optic nerve), can cause a progressive loss of vision. Some common symptoms of conditions that cause a progressive loss of vision include:

  • pain in the eyes,
  • blurring of vision,
  • halos appearing around sources of light,
  • severely reduced night vision (the ability to see at night), and
  • problems seeing in bright sunlight conditions, or well-lit rooms.

See your GP if you notice any deterioration in either your vision or hearing. Some conditions, such as cataracts, can be successfully treated before significant damage to your sight occurs.

You should also see your GP if you have repeated ear infections because this could increase the risk of hearing loss.

Treatable sight and hearing conditions

If the conditions that have lead to deafblindess are treatable, through surgery, or using medicines, then your treatment will begin.

Treatable sight conditions include:

  • cataracts – which can be treated by surgically implanting an artificial lens in your eye, and
  • glaucoma – which can be treated using eye drops and laser surgery.

Diabetic retinopathy can also be treated with laser surgery, but only in the early stages of the condition, before symptoms become noticeable. See the 'prevention section' for more details about this.

Treatable ear conditions include:

  • otitis media – which is an infection of the middle ear and can usually be treated with antibiotics, and
  • accumulated earwax – is one of the most common causes of hearing loss, and can be treated with ear drops, or by syringing. Syringing involves using lukewarm water to dissolve the wax. It is not recommended to use cotton buds to clear out earwax, as they can push the wax deeper inside.

Non-treatable sight and hearing conditions

If the conditions that have lead to deafblindess are not treatable, a treatment plan will need to be drawn up. Goals of the treatment plan may include:

  • preserving and maximizing any remaining sensory functions that you have,
  • providing you with training so that you can retain as much independence as possible. For example, you may be provided with support and advice about how to navigate safely in the outside environment, using a cane, or a guide dog, and
  • teaching you one, or more, communication systems that you can use in order to compensate for the loss of your vision and sight.

The treatment plan will depend on the exact circumstances of your deafblindness because a different approach will be required for each indivuidual circumstance. Some possible circumstances leading to deafblindness may include:

  1. you are born deafblind,
  2. you have adapted to being blind, but then start to lose your hearing,
  3. you have adapted to being hearing impaired, but then start to lose your vision, or
  4. you are losing both your hearing and vision as you get older. (This is the largest group of deafblind people).

Equipment to assist vision

There is a range of equipment that can be used to assist both vision and hearing.

Vision can be assisted using glasses and magnifying lenses. There is also a range of everyday items, including telephones and keyboards, which have been specially designed for people with reduced vision.

If you are a computer user, all operating systems have settings designed for people with reduced vision. You can also download free software from the Browsealoud website that will read aloud the text from speech enabled websites. Many of the major websites including Google, the BBC, plus most public information sites are now speech enabled.

For websites that are not speech enabled, and in order to read documents and emails, you may need to buy additional software. Both the Sense and RNIB websites provide details of appropriate software.

Most libraries stock a selection of large print books and 'talking books' (where the text of the book is read aloud and recorded onto a CD). The RNIB also offer a talking book service, where a wide range of talking books can be delivered to your house for a small subscription fee.

Equipment to assist hearing

Hearing impairment may be improved with the use of hearing aids. A hearing aid consists of a microphone to pick up sound, and an amplifier, to amplify (increase) the sound. Hearing aids are a helpful way of improving communication, but they cannot restore hearing to normal.

There are many different types of hearing aids. The most commonly used types are outlined below.

  • Behind-the-ear-hearing aid (BEHA) – consists of a plastic case, which is often skin-coloured, that contains a microphone, an amplifier, and a loudspeaker. It sits just behind your ear lobe, and increases the volume of sounds as they enter your ear.

  • In-the-ear-hearing aid (ITEHA) – is a smaller, less powerful hearing aid that sits inside the ear. The ITEHA may not be suitable for you if you have severe hearing impairment because it is too small to contain a very powerful amplifier.
  • Completely-in-the-Canal-Hearing Aid – is a very small device which can be used by people with mild hearing impairment. It fits completely inside your ear canal and is almost unseen from outside the ear.

People with profound hearing impairment may benefit from a cochlea implant. The cochlea is a coiled, hollow tube located inside you inner ear that enables you to hear. A cochlea implant transmits sound directly into your ear's auditory nerve through an electrical wire that is implanted into the cochlea.

Communication systems

There are several different communication systems that can be used by deafblind people. These are outlined below.

Deafblind manual alphabet

The deafblind manual alphabet involves spelling out words using special gestures on the deafblind person's hands, such as touching the tip of their thumb to spell the letter 'A'.

Block alphabet

The block alphabet is a more primitive version of the deafblind manual alphabet, where each letter of a word is spelt out in capital letters on to deafblind person's palm. This is normally used by people who have not learnt the deafblind manual alphabet.

Hands on signing

The deafblind person places their hands over the hands of the person who is signing. This method is often used by people with Usher syndrome once their vision starts deteriorating as, usually, they will have already learnt BSL.

Tadoma

Tadoma is a communication method whereby the deafblind person places their thumb on a person's lips and their fingers on their jaw line so that they can feel the vibrations of the person's throat. The combination of these two tactile (using the sense of touch) sensory inputs, enables the deafblind person to build up a good understanding of what is being said.

Braille

Braille uses a series of raised dots to represent letters, or groups of letters. There are a wide range of braille publications and specially designed computers are also available that allow you to type and print braille documents.

Moon

Moon is a communication system that is similar to braille, but it uses raised symbols to represent words, rather than dots.