The World Health Organisation adopts the following definition of dyslexia:
○ ICD-10, The International Statistical Classification of Diseases and Related Health Problems, tenth revision.
○ ICIDH-2, The International Classification of Impairments, Activities, and Participation.
A disorder manifested by difficulty learning to read, despite conventional instruction, adequate intelligence and sociocultural opportunity. It is dependent upon fundamental cognitive disabilities which are frequently of constitutional origin.
F81.0 Specific reading disorder
The main feature is a specific and significant impairment in the development of reading skills that is not solely accounted for by mental age, visual acuity problems, or inadequate schooling. Reading comprehension skill, reading word recognition, oral reading skill, and performance of tasks requiring reading may all be affected. Spelling difficulties are frequently associated with specific reading disorder and often remain into adolescence even after some progress in reading has been made. Specific developmental disorders of reading are commonly preceded by a history of disorders in speech or language development. Associated emotional and behavioural disturbances are common during the school age period.
Specific reading retardation
F81.1 Specific spelling disorder
The main feature is a specific and significant impairment in the development of spelling skills in the absence of a history of specific reading disorder, which is not solely accounted for by low mental age, visual acuity problems, or inadequate schooling. The ability to spell orally and to write out words correctly are both affected.
On the one hand, the WHO recognises that access to information through digitally accessible information systems, talking books, etc, is a “human right”, and is “defined as such in the United Nations Convention on the Rights of Persons with Disabilities, which to date has 149 signatories and came into effect in May 2008”.
On the other hand, the organisation lists dyslexia as being a “minor learning difficulty” and an “[i]mpairment […] in information processing resulting in difficulties in listening, reasoning, speaking, reading, writing, spelling, or doing mathematical calculations”. In one report, the WHO categorised dyslexia among “other health conditions found in young people included speech problems, dyslexia, cerebral palsy, vision disorders, and congenital abnormalities”.
See for instance: