2nd March 2010

INMD 2008/2010

These are notes, links and supporting references from the INMD workshops of 2008 through 2010. Statistics were last updated in 2010.

Addendum – 2015

Although ICD-10 remains the current Standard for almost all health systems globally, ICD-11 is nearing completion for release in 2018, see: ICD-11 Draft. Key differences in respect of ID include dropping the descriptor ‘Mental Retardation’ in favour of ‘Disorders of Intellectual Development’ and also a move away from ‘Mental Ages’ when characterising degrees of impairment. ICD-11 also aims to harmonise with DSM-V which will have more profound implications for clinical classification of intellectual and developmental disabilities.

Progress has also been made with ICF since the notes below were written – including the merging of ICF and ICF-CY see: ICF Website. WHO ICF is the global Standard which underpins modelling of adaptive functioning/behavior and individual context in respect of disability and health.

Additionally, WAI are producing supporting guidance which includes consideration of some discrete disorders and conditions associated with intellectual disability see: Cognitive A11Y TF. In the web accessibility space, disabilities caused by impairments which are other than physical or sensory are often referred to as ‘Cognitive Disabilities’ which consequently has a very much wider scope than Cognitive Impairment in the usual sense.

INMD Workshop Notes – 2010

Definitions of Intellectual Disability

Intellectual Disability is an internationally neutral term which encompasses Moderate, Severe and Profound Learning Difficulties [UK Education] and is equivalent to Learning Disability [UK Social and Health Services] or Mental Retardation [some clinicians and WHO].

It can be over-simplistically defined as a mental impairment present at birth or acquired in early life (in the US under 18 years, elsewhere in infancy) resulting in a standardised IQ score of less than 70 points (ie normal less twice standard deviation at 15 points).

Although IQ testing may form part of the process, a diagnosis of ID is mainly made through assessment of adaptive skills. The WHO in ICD-10 provides the following overview of groupings within ID – as Mental Retardation. These definitions provide a convenient way of indicating the range of abilities across the population but terms like ‘mental age’ are anachronistic and rarely used by professionals in the UK.

  • Mild
    Approximate IQ range of 50 to 69 (in adults, mental age from 9 to under 12 years). Likely to result in some learning difficulties in school. Many adults will be able to work and maintain good social relationships and contribute to society.
  • Moderate
    Approximate IQ range of 35 to 49 (in adults, mental age from 6 to under 9 years). Likely to result in marked developmental delays in childhood but most can learn to develop some degree of independence in self-care and acquire adequate communication and academic skills. Adults will need varying degrees of support to live and work in the community.
  • Severe
    Approximate IQ range of 20 to 34 (in adults, mental age from 3 to under 6 years). Likely to result in continuous need of support.
  • Profound
    IQ under 20 (in adults, mental age below 3 years). Results in severe limitation in self-care, continence, communication and mobility. .

The ICF from the WHO is a more constructive framework and better reflects UK practice in the personalisation of assessment and classification for people with ID.

Learning Disability or Intellectual Disability?

Most of my clients in the UK use the term ‘Learning Disability’ rather than Intellectual Disability and within the UK Social and Health Services their meaning is fairly clear. Unfortunately in other contexts, the UK’s usage of the term Learning Disability is problematic, since for most of the world it denotes a more prevalent and nebulous group of largely scholastic disabilities – including dyslexias, attention deficit disorders and much else.

The terms Moderate, Severe and Profound Learning Difficulties are used throughout compulsory education in the UK and in successive UK Education Acts, but these terms are rarely employed beyond it. Although UK Education officially employs the term ‘Specific Learning Difficulties’ to denote scholastic disabilities such as those characterised as dyslexia, the import of pedagogic approaches and expertise from the US has also led to an increased use of ‘Learning Disability’ to denote such conditions.

Use of ID is gaining ground partly as a response to this confusion of terminology and has now been adopted by governments of New Zealand, Australia, Canada and Ireland amongst others. Likewise many US organisations are renaming themselves in similar terms, moving away from clinical labels such as ‘mental retardation’ which have negative connotations.



Note that where some UK organisations below use the term ‘learning disability’ it is to denote intellectual disability, they are not refering to scholastic disabilites such as dyslexias, ADD or other specific cognitive impairments.

UK Figures – ‘Hatton’

Hatton’s estimates are favoured by clinical academics.

  • Mild ID – 18 per 1000 people.
  • Severe ID – 3 to 4 per 1000 people.

Source: Emerson C, Hatton C, Bromley J & Caine A (1998) Clinical Psychology and People with Intellectual Disabilities. Wiley and Sons

UK Figures – ‘Valuing People’

Another widely quoted statistic originates from the UK Government Whitepaper ‘Valuing People’ and estimates the 1999 figures for incidence of ‘Learning Disabilities’ at:

  • Mild Learning Disabilities – 25 per 1000 people or 1.2 million people in total.
  • Severe and Profound Learning Disabilities – 210,000 people.

Source: Valuing People Whitepaper, UK Government 2001

UK Figures – ‘Mencap’

Mencap’s 2010 statistics:

  • 1.5 million people in the UK have a learning disability.
  • 200 babies are born with a learning disability every week.
  • 8 out of 10 people with a learning disability get bullied.
  • There are more than 29,000 people with a severe or
    profound learning disability who live at home with
    carers aged over 70.
  • Less than 1 in 5 people with a learning disability work (compared with 1 in 2 disabled people generally)
  • Less than a third of people with a learning disability have some choice of who they live with, and less than half have some choice over where they live.
  • At least half of all adults with a learning disability live in the family home
  • Just 1 in 3 people with a learning disability take part in some form of education or training.

Source: Mencap Website, 2010

UK Figures for Adults with Profound ID – ‘Emerson’

Individuals with profound ID almost always have complex medical needs, multi-sensory impairments and significant physical disabilities. Such individuals historically have had limited life-expectancy and therefore children with profound ID have outnumbered adults. Emerson’s 2009 figures have been adopted by UK Goverment and currently estimate that there are around 16,000 adults in England (equates roughly to 19,000 throughout the UK) with profound ID.

Source: Emerson, E. “Estimating future numbers of adults with profound multiple learning disabilities in England”. Lancaster: Centre for Disability Research, 2009

US Figures – AAIDD

AAIDD’s 2010 statistics:

  • Between 7 and 8 million people in the US have an intellectual disability.
  • Intellectual disability affects 1 in 10 US families.

Source: AAIDD, 2010

UK Demographics

Almost all sources and researchers agree that there is a strong link between lower socio-ecomonic groups and a higher prevalence of mild and moderate ID. In contrast severe ID are usually found to be evenly dispersed across all socio-economic groups in the UK and other wealthy countries. There are however strong links between the breakdown of families and subsequent economic hardship following the birth of a child with ID. Mencap estimate that half of UK families with a disabled child live in poverty.

International Figures

Incidence of ID in the UK is similar to that of most EU countries and the USA. In many developing countries general poverty and low standards of medical care, particularly perinatal, lead to very much higher incidence of all degrees of ID.

Future Figures

Due to increased life-expectancy and an aging population, the number of people with all levels of ID is increasing in the UK by about 1 percent per annum. The Valuing People Whitepaper predicts this will continue until at least 2015.

Additionally, the last decades have seen huge improvements in peri-natal care which has, perhaps counter-intuitively, led to a significant rise in the number of young people with severe and profound ID. Some estimates in respect profound ID population increase are as high as 500% over the past twenty-five years. Life-expectancy for this group is likely to remain much lower than average, but many more children are expected to survive into adulthood. Emerson’s (2009) estimates are widely considered reliable and suggest that the number of adults with profound ID is currently increasing by 1.8% a year and will continue to do so at a similar rate until 2026.

Web Links

The following references are useful sources of more information about ID.


  • Mencap is largest of the UK charities concerned with ID and the most influential at governmental policy level. In addition to its campaigning role, Mencap also provide many services to people with ID including specialist educational provision and residential care.
  • The Foundation for People with Learning Difficulties is a lobbying, research and support organisation which works closely with ID people, their families and their professionals.
  • The Valuing People Whitepaper ushered in a massive shift in UK policy in respect of people with ID. Although progress towards its goals was regionally fragmented, and therefore viewed by many as little more than rhetoric, this document and subsequent initiatives should have represented a sea-change in the rights and expectations of people with ID throughout the UK. The agenda has recently been revitalised with a greater governmental committment to consistency of implementation in Valuing People Now.


  • International Association for the Scientific Study of Intellectual Disabilities is an international and interdisciplinary scientific non governmental organization with official relations with the World Health Organization. It promotes worldwide research and exchange of information on intellectual disabilities. IASSID is the first and only world-wide group dedicated to the scientific study of ID.
  • The American Association on Intellectual and Developmental Disabilities is the largest USA professional association run by and for professionals who support people with intellectual and developmental disabilities. It promotes progressive policies, sound research, effective practices and universal human rights for people with ID.
  • Inclusion International is a global federation of family-based organizations advocating for the human rights of people with ID worldwide. II represents over 200 member federations in 115 countries throughout five regions Middle East and North Africa, Europe, Africa and the Indian Ocean, the Americas, and Asia Pacific.

Standards and Classification

  • The WHO ICD-10 provides clinical definitions of Mental Retardation in Chapter 5, F70-F79.
  • The WHO ICF provides an international standard framework for the assessment of adaptive skills, levels of disability, healthcare requirements and support needs, including those of people with ID.


Web Accessibility References

  • Whizzo On Trial
    Transcript of a 2008 talk at INMD by Kevin Carey (Chair of HumanITy and RNIB).
    The context of this talk related to the user-testing activities developer participants were about to undertake with groups of intellectually disabled users, though it covered a much wider group. Kevin challenged many received wisdoms in respect of current Web accessibility practice, noting that there is often little understanding of disability demographics amongst accessibility experts and that basic assumptions in respect of Web design and usability evaluation are frequently flawed. Most surprising for the audience was probably the statistic that even in the UK, where Internet availability is relatively high, less than 10 percent of blind people use a screen reader to access the Web. Looking at the demographics in terms of age and disability, it also became clear that the vast majority of accessibility guidelines such as WCAG are only relevant to a small section of the disabled population.
  • Inclusive New Media Design
    Output from a 2 year research project looking at the barriers to accessible design experienced by accessibility-committed Web professionals which had a particular focus on intellectual disabled audiences. The project also coincided with the final drafting of WCAG 2.0 and some interesting perspectives on this work from developers and designers emerged. A critical part of the project centred on bringing a range of professionals from design, development and information architecture roles together with several groups of intellectually disabled user-testers.
  • Inclusion Of Cognitive Disabilities in the Web Accessibility Movement – Lisa Seeman, UB Access.
    This paper explores the attitude and accomplishments towards including Cognitive Disabilities within the Web Accessibility movement. It then suggests practical steps that could be taken to increase the usefulness of Web Accessibility for the Cognitively Disabled.
  • Developing sites for users with Cognitive disabilities and learning difficulties – Juicy Studio.
  • An Accessibility Frontier: Cognitive disabilities and learning difficulties – Hudson, Weakley and Firminger.
    This article by Roger Hudson, Russ Weakley, and Peter Firminger, examines the types of problems visitors may encounter when using the web, with insightful and practical suggestions on how to develop websites that are inclusive for people with cognitive impairments and learning difficulties.
  • Assessing the reading comprehension of adults with learning disabilities
    Jones, F., Long, K. and Finlay, W., 2006. Journal of Intellectual Disability Research 50(6), pp.410-18. Text and language usage online is the greatest barrier to Web accessibility for people with intellectual disabilities – in fact the baseline reading level set by WCAG 2.0 even at Level AAA [3.1.5 Reading Level] actually excludes upto 20% of the general UK population, not just the 2% or so with intellectual disabilities. This study produced some interesting results, suggesting that even functionally literate adults with borderline intellectual disabilities have a far lower reading comprehension age than might be expected, peaking within primary school levels and with median reading comprehension ages in the 6-7 years range.
  • Accessible Website Content Guidelines for Users with Intellectual Disabilities
    Karreman, J., van der Geest, T. and Buursink, E., 2007. Journal of Applied Research in Intellectual Disabilities, 20(6), pp.510-18. Some suggested techniques for the development of Easy Read content which was user-tested by a small sample group with intellectual disabilities.
  • Making the Internet accessible for people with cognitive and communication Impairments. Poulson, D. and Colette, N., 2004. Universal Access in the Information Society , 3(1), pp.1615-5297. Call for more guidance and standards addressing the access needs of intellectually disabled Web users with particular focus on symbol use. Output from the World Wide Augmentative and Alternative Communication project.
  • Web Accessibility for People with Cognitive Disabilities Small, J., Schallau, P., Brown, K. and Appleyard, R., 2005. In Conference on Human Factors in Computing Systems : CHI 2005. NY, 2005. ACM. A pilot study user-testing WCAG (1.0) Compliant Websites with intellectually disabled people. Unsurprisingly the sites were inaccessible to user-testers, but the paper also considers how Web content guidelines might better serve this audience.
  • Communication and Empowerment: A Place for Rich and Multiple Media? Bunning, K., Heath, B. and Minnion, A., 2009. Journal of Applied Research in Intellectual Disabilities., 22(4), pp.370-79. Paper coming out of a project I worked on for 2 years prototyping an accessible learning platform for intellectually disabled students. In particular the paper considers the usefulness to young people with intellectual disabilities of creating and using rich media in their communication and self-advocacy.
  • Web accessibility design recommendations for people with cognitive disabilities G. Friedman, M. and Bryen, D., 2007. Technology and Disability, 19(4), pp.205-12. A broad literature review summarising 20 sets of accessibility guidelines for people with intellectual disability gathered both from published articles and organisational Web sites. Guidelines were collated and combined to produce a weighted list of approaches to accessible design for this audience – although some guidelines were also related to scholastic and generic cognitive disabilities, rather than intellectual disabilities in isolation.
  • Formal Objection to WCAG 2.0 raised during the drafting of WCAG 2.0 in respect of failure to address the needs of Web users with intellectual, learning and other cognitive disabilities. This was signed by thirty-some organisations and individuals working with cognitively disabled people in Web and new media related areas. Though it didn’t lead to a change of direction in respect of the Normative Guidance, it did at least put aside notions of universal accessibility in the document and resulted in the inclusion of an (ever-shrinking) acknowledgement that a very large number of disabled users are still excluded by the scope and nature of WCAG 2.0
  • Am I Making Myself Clear? is a document from Mencap concerned with accessible writing for people with intellectual and learning disabilities. This guidance is referenced by the PAS78 Web Accessibility Guidance from BSI in the UK.