Finding out about learning disability
Facts and figures
Facts and figures
Learning disabilities can also be referred to as 'learning difficulties' or 'mental impairment'. 'Learning difficulties' is a more generic term describing mid-intellectual disabilities. 'Mental impairment' describes significant intellectual disability and difficulty with social functioning.
There is often no known cause of learning disabilities; where a cause can be identified it falls into the following categories:
- Before birth e.g. chromosome abnormalities
- Birth complications e.g. prematurity, asphyxia
- Post natal reasons e.g. infections, trauma
Learning disabilities are often accompanied by secondary conditions such as Down's Syndrome, epilepsy, challenging behaviour, Autistic Spectrum Disorder or mental health problems.
Learning disability or learning difficulty?
These two terms quite often get interchanged. Do they strictly mean the same? There does seem to be a difference in application of the term by some parties. 'Learning Difficulty' appears to be the more generic term and may not necessarily be associated with intellectual disability (more later). Gifted or exceptional children are sometimes described as having a learning difficulty as are dyslexic children. People with mild intellectual disability appear to be also more readily described as having a learning difficulty. The word 'difficulty' in a dictionary refers to; 'complex', 'not easy', 'laborious' 'demanding', and 'arduousness'. This does not necessarily imply an enduring state - it perhaps has the suggestion of a particular task being a heavy challenge and possibly transitional.
When examining the word 'disability', such descriptions as; 'affliction', 'ailment', 'incapacitated', 'malady', infirmity', 'weakened' and 'handicapped' can be found. Whilst these terms may appear stigmatising at first, you can begin to see the suggestion of a more personal, substantial and permanent state of impairment.
It has been argued, mostly by clinicians, that the term 'intellectual disability' is a more accurate description of the nature of the disability faced by individuals. This term finds favour in both America and Australia. In America it relates to 'a significant intellectual impairment and deficits in social functioning or adaptive behaviour (i.e. basic everyday skills) which are present from childhood'.
The term learning disability appears to be the chosen term of the United Kingdom Government, having been adopted since 1996. People First, the self-advocacy organisation, makes the valid point that they would prefer no label! However, learning difficulties is their preferred description of the problems they face.
Mental Impairment
Mental Impairment is another term sometimes found. This is a medico-legal term which is often used in mental health legislation, such as The Mental Health Act 1983. (You can also find it presenting in some state benefit regulations, where it has differing definitions again).
Mental Impairment (and similarly the category of 'severe mental impairment') is described in the Mental Health Act as consisting of:
- Arrested or incomplete development of mind
- Significant impairment of intelligence and social functioning
- Abnormally aggressive or seriously irresponsible behaviour
As can be seen by this definition a person would need to have significant intellectual disability and significant difficulty regarding their social functioning, plus behaviour problems that are seen as either seriously irresponsible (although what is 'irresponsible' is not defined) or aggressive to have Mental Impairment.
The presence of all three above conditions are required and this is important because now only intellectually disabled people who have acute behaviour problems can be considered for compulsory hospital admission. Being solely intellectually disabled is not sufficient grounds for compulsory admission. In previous eras (up to 1983) people were 'detained' in long stay mental handicap hospitals just on the grounds of their mental disability alone and because they were considered vulnerable and could not care for themselves. The vast majority did not display behavioural problems.
Impairment, disability and handicap.
It may also be useful at this stage to clarify the differences between the usage of such terms as impairment, disability, and handicap.
- Impairment is the loss of some physical or intellectual function
- Disability refers to what you cannot do because of the original loss or impairment
- Handicap is what you socially experience as a result of the impairment or disability. Many negative social experiences can increase the impacts of primary impairments or disabilities
For example, a person may have Macular Degeneration in the retina of their eyes (the impairment) and as a result cannot see or have poor vision (the disability) and because of this may be unable to do certain types of work for which eyesight would be essential (a handicap). There may be additional difficulties caused by erroneous assumptions about mental capacity, being able to speak for oneself, and the ability to travel independently. These negative perceptions constitute further handicap.
Intelligence Quotient.
Intelligence Quotient, or I.Q. is a measurement of intelligence. It used to play a greater part in learning disability professional practice in years gone by, but still has a degree of relevance today. It is more likely to be used at a diagnostic stage or in court related forensic work.
I.Q. is a form of psychometric testing performed by psychologists. There are numerous tests which compare an individual with others, referenced to an absolute standard. In this way people are measured against the 'norm'. There have been many criticisms of these tests in the past due to the fact they provide a static snap shot picture and are considered by some to have a cultural bias. However on occasions, they can still provide a useful potential measure of a person's intellectual disability.
I.Q. scores are used to describe clinical levels of intellectual disability and these are set out below.
I.Q < 20. Profound intellectual disability (4%)
I.Q. 20-35. Severe intellectual disability (6%)
I.Q. 35-50. Moderate intellectual disability (15%)
I.Q. 50-70. Mild intellectual disability (75%)
An average I.Q. score is said to range from 80-120
Prevalence of learning disability.
There are no accurate official statistics to say exactly how many people with severe intellectual disability are resident in the United Kingdom (which is perhaps suprising, given the amount of official information which is stored).
The presence of severe learning disability in the community, has been shown to be around 3 in 1000. This seems to be a consistent figure for most developed countries. Some epidemiological studies have estimated there are around 160,000 people with severe learning disabilities living in England.
The 'Valuing People' Government white paper suggests there are around 210,000 people with profound and severe learning disabilities in England, this number comprising of 65,000 children, 120,000 adults and 25,000 older people. The case for mild and moderate learning disability suggests a prevalence rate of around 25 per 1000, approximately 1.2 million people in England. The Government believes evidence is emerging that the number of people with severe learning disabilities in the community may increase over the next 15 years. This is because of increased life expectancy (especially for people with Down's Syndrome), plus other factors such as a growing number of children with complex and multiple disabilities who are now surviving into adulthood, increased numbers of children with autistic spectrum disorders who have severe learning disabilities and a greater prevalence found in some ethnic minority groups.
What causes intellectual and learning disability?
Whilst often there is no known reason for the cause of a person's intellectual disability, where a cause is identified it can fall into the following categories:
- Before birth
Chromosome abnormalities such as Down's Syndrome, Tuberous Sclerosis
Infection. e.g. Rubella
Lack of oxygen to the foetus (Anoxia)
Trauma (e.g. accident or injury in some way)
Vaccine damage
Poisons. e.g. drugs (legal or illicit), alcohol, smoking, and lead
- Birth Complications
Asphyxia and anoxia
Obstructed birth and extended labour
Instrument birth and brain damage
Extreme prematurity and very low birth weight
- Postnatal reasons
Infections e.g. Meningitis
Trauma e.g. accident, injury, child abuse
Metabolic or disorders of nutrition and growth e.g. Phenylketonuria
Social deprivation
Down's Syndrome.
Down's Syndrome is the most common cause of learning disability of all degrees of severity. Some 600 babies are born in the U.K. annually with the condition. The incidence appears to be rising with the observed prevalence having increased to 1.04 per 1000 live births in 1998. This now accounts for nearly a third of all severe learning disabilities. The reason for this increased rate is thought to surround the tendency for women to have babies at a later age. The chances of a mother having another child with Down's Syndrome is said to be at much the same level as her previous birth (plus reference to her current age). The condition is thought to be inherited in about only three percent of cases, the main reason being accidental chromosome abnormalities at the point of conception.
Life expectancy has changed dramatically for people with Down's Syndrome. A person born with Down's Syndrome in 1929 could only expect to live on average until they were nine years of age. By the 1950s this increased to fifteen years of age. Now with improved heart surgery, medicines and general care, they can easily live into their fifties with some showing extended survival into their seventies. It is estimated that there are around 60,000 people with the condition in the UK.
Learning Disability and Epilepsy.
The prevalence of epilepsy in the general population has been estimated at 5-10 per 1000 people (<0.01%). The National Society for Epilepsy reports that the frequency of epilepsy in people who have a learning disability is higher than the general population. In people who have mild learning disability it is around 60 per 1000 (6%) which is approximately 10 times higher than in the general population.
About 30 percent of the learning disability population have some form of epilepsy and this increases to 50 percent for those who have severe learning disability. Having a learning disability does not cause epilepsy and vice versa. What is common to both is an underlying brain dysfunction or damage. Tonic-clonic seizures are the most common symptom in people who have both learning disability and epilepsy. These are present in 60 percent of the population whilst complex partial seizures amount to 20 percent.
Learning Disability and Challenging Behaviour
Estimates of the incidence vary due to the differing definitions of challenging behaviour amongst observers. However, studies have suggested that between 12 and 17 percent of the population who have a learning disability will show some degree of challenging behaviour. This is a rate of around 0.5 per 1000 of the general population (i.e. 50 individuals) amongst whom approximately half again will show severe challenging behaviour.
The overall prevalence of challenging behaviour is said to increase with age during childhood and is at its peak in the age range 15-34 years. After this, it then appears to decline. It is found more in males than females and appears to be correlated with the degree and severity of intellectual disability.
Learning Disability and Autistic Spectrum Disorder
It has been suggested that around 50 percent of people who have a severe learning disability show symptoms of Autistic Spectrum Disorder (i.e. around 1.5 per 1000 of the general population). People who have mild learning disabilities are much less affected with only around five percent of the group having symptoms (i.e. 1.25 per 1000 of the general population).
Learning Disability and Mental Health Problems.
People with learning disabilities are more likely to experience mental health problems than members of the general population. It is said that about 25 percent of people, are likely to have some mental health problem in their lifetime. This compares with surveys reporting rates of psychiatric disturbance in people who have a learning disability as being between 25 and 40 percent.
