Intellectual disability in children and adolescents

Intellectual disability is a condition caused by delayed or abnormal development in a child. Intellectual disability presents differently for different people but always involves some degree of permanent cognitive impairment and difficulty functioning in everyday life.

What is intellectual disability?

A diagnosis of intellectual disability primarily entails cognitive impairment. The term “cognitive function” describes the ability to perceive, assess, process, store, retrieve and purposefully act on information from a person’s surroundings. 

Intellectual disability is graded as mild, moderate, severe and profound. The symptoms experienced by the child vary greatly and depend on the degree of intellectual disability. 

Children and adolescents with intellectual disabilities may require support and facilitation in various areas and at various times in their lives in order to cope and achieve a good quality of life. 

Symptoms of intellectual disability

Development during the first few years of life is unique to each child. Nevertheless, development follows a certain pattern as to when and in which order children develop and master various skills, such as eye contact, taking their first steps, saying their first words and interacting with other children and adults. 

In the absence of development of skills in one or more of these areas or when development is delayed, the child or adolescent may have an intellectual disability. 

A diagnosis of intellectual disability is normally graded as mild, moderate, severe or profound. 

Mild intellectual disability 

Children and adolescents with a mild intellectual disability usually have difficulty learning in school. As adults, many will be able to work and develop positive social relationships. Some facilitation and adaptation of training and education will often be necessary. 

Moderate intellectual disability 

Most children and adolescents with moderate intellectual disability will develop some degree of independence. With adapted training, they will, to some degree, be able to look after themselves, communicate and develop some self-help skills. As adults, they may require varying degrees of support in everyday life, both in terms of activities of daily living and employment. 

Severe intellectual disability 

Children and adolescents with severe intellectual disability will usually have a continuous need for care. 

Profound intellectual disability 

Children and adolescents with profound intellectual disability will, from infancy, have severe impairments with regard to communication, movement and the ability to care for themselves. 

Mental age and intellectual disability 

The term mental age is often used to explain the different degrees of intellectual disability. This helps to provide an indication of the child or adolescent’s cognitive maturity at any given time and of their developmental opportunities. 

However, mental age cannot be compared directly with chronological age. An adult with an estimated mental age of 6-9 years naturally has far greater life experience than a child with a chronological age of 6-9 years  while the ability to learn new skills, for example, may be consistent with mental age. 

Impaired cognitive function and other challenges 

In addition to impaired cognitive function, children and adolescents with intellectual disability may experience other challenges, such as: 

  • Delayed or inadequate development of movement and body control, language and communication. 
  • Limited independence in managing activities of daily living. 
  • Increased risk of developing physical and mental illness. 

Causes

There can be many causes of intellectual disability. Some are congenital, while others occur after birth. It is not always possible to identify the cause of an intellectual disability. Some examples of causes of intellectual disability include: 

Genetic factors that can explain the cause of an intellectual disability 

Genetic is not synonymous with hereditary, but refers to changes in the chromosomes of the child or adolescent. Chromosomes are found in every cell in the body and contain our genetic material, DNA. Changes in these chromosomes are often called chromosomal abnormalities. 

Down’s syndrome (trisomy 21) is the most common single cause of intellectual disability due to chromosomal abnormalities. A number of other syndromes and rare diseases can cause intellectual disability, such as: 

Rett syndrome (frambu.no) 

Fragile X syndrome (frambu.no) 

Acquired factors that can explain the cause of an intellectual disability 

  • Infection in the mother during pregnancy. 
  • Impact of alcohol, drugs or medications during pregnancy. 
  • Acquired brain injury early in life, which may occur after a fall, blow to the head, infection, cerebral haemorrhage, oxygen deficiency, lack of blood supply, brain tumour or similar. 

Evaluation and diagnosis

Evaluation 

If parents/guardians have concerns about the development of children or adolescents, they can get help with evaluations from the local educational and psychological counselling service (PPT) and various hospital departments, such as the children’s ward, the habilitation service (HABU) and mental healthcare services for children and adolescents (BUP). 

The hospital will investigate the cause of the intellectual disability. 

It can take time before an intellectual disability is discovered 

Intellectual disability is usually a congenital condition, but the parents/guardians and others in the child’s life do not always discover that there is a developmental delay before some time has passed. This may be because it is a mild intellectual disability and it may be some time before there are expectations set that the child cannot meet due to their intellectual disability. 

Diagnosis 

In order to be diagnosed with an intellectual disability, a child needs to show an IQ of less than 70 in intelligence tests. In addition to intelligence tests, motor skills, language, social skills and the ability to manage activities of daily living are also mapped. The difficulties must have presented before the age of 18. 

Diagnosis can be made at pre-school age or later. Sometimes, the severity will only be determined after the child has attended school for a couple of years. 

Living with an intellectual disability 

Intellectual disability is a lifelong condition and there is no cure. Intellectual disability may be part of a complex condition that requires specialised medical follow-up and measures to prevent complications. 

Follow-up and facilitation 

Follow-up, information and facilitation are all important both for the child and for the family’s ability to adapt to and live with the unexpected challenges that a diagnosis of intellectual disability may entail. 

What the intellectual disability will mean for each child or adolescent depends on a number of factors, such as: 

  • the degree of intellectual disability 
  • other disabilities or illnesses 
  • treatment, follow-up and training 
  • facilitation in kindergarten, school, living environment or leisure activities 
  • how coordinated the support measures are 

All children and adolescents with intellectual disabilities will require somewhat more help than other children and adolescents in order to develop and learn. Children and adolescents with intellectual disabilities will require assistance and facilitation in order to utilise and build on the resources they have so that they can achieve the greatest possible range of life skills. 

Kindergartens, schools, the educational and psychological counselling service and other local authority services are responsible for such adaptations in collaboration with parents/guardians. What the child needs help with and how much help they require will be unique to each child. 

Follow-up in the specialist health service 

Specialist healthcare from various units at the hospital may also be appropriate. This may include diagnostic tests, treatment of mental health conditions or dental treatment under general anaesthesia. Hospital referrals will be made by the GP. 

Rights

Coordinator and individual plan 

Anyone who requires long-term, coordinated services has the right to a coordinator, who will be responsible for the follow-up of the individual. The coordinator will, among other things, ensure coordination and progress in the work on the individual plan (IP). This also applies to children and adolescents with intellectual disabilities. 

In order to initiate the work on the individual plan and to be assigned a coordinator, please contact the allocation office in the municipality where you live. If the child or adolescent is being followed up in a hospital, the hospital department can also contact the appropriate agency in your municipality to initiate work on the individual plan. You can also contact your GP or a child health clinic for help.  

Choosing a treatment centre

You have the right to choose where examinations and treatment that you or your child have been referred for will take place. Under Select treatment centre, you can see that the waiting times may vary. 

Norsk forbund for utviklingshemmede

Norsk forbund for utviklingshemmede arbeider med å bedre vilkårene for mennesker med utviklingshemming.

Pivalizza P og Lalani SR. Intellectual disability in children: Definition, diagnosis, and assessment of needs [Internett]. Oppdatert juli 2018, litteraturgjennomgang oktober 2020, i UpToDate Patterson MC, Firth HV, og Armsby C (red.) [hentet 2020-11-11]. Tilgjengelig fra: https://www.uptodate.com/contents/6172

Pivalizza P og Lalani SR. Intellectual disability in children: Evaluation for a cause [Internett]. Oppdatert juli 2018, litteraturgjennomgang oktober 2020, i UpToDate Patterson MC, Firth HV, og Armsby C (red.) [hentet 2020-11-11]. Tilgjengelig fra: https://www.uptodate.com/contents/intellectual-disability-in-children-evaluation-for-a-cause

Pivalizza P. Intellectual disability in children: Management, outcomes, and prevention [Internett]. Oppdatert juli 2018, litteraturgjennomgang oktober 2020, i UpToDate Patterson MC, Firth HV, og Armsby C (red.) [hentet 2020-11-11]. Tilgjengelig fra: https://www.uptodate.com/contents/6191

Content provided by Oslo University Hospital

Oslo University Hospital. Intellectual disability in children and adolescents . [Internet]. Oslo: The Norwegian Directorate of Health; updated Monday, May 15, 2023 [retrieved Thursday, December 5, 2024]. Available from: https://www.helsenorge.no/en/sykdom/skader-og-sykdommer-i-hjernen/utviklingshemming-hos-barn-og-unge/

Last updated Monday, May 15, 2023