Cognable

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], Developmental Disability or Mental Retardation [USA and WHO]. It can be over-simplistically defined as a mental impairment present at birth or acquired in early life resulting in a standardised IQ score of less than 70 points (ie normal minus twice the 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.