What is dyslexia?

A new definition of dyslexia

In 2024, a new definition of dyslexia was developed following a substantial period of research. When making a diagnosis, this definition is referred to. It defines dyslexia in the following ways:

Nature
• The nature and developmental trajectory of dyslexia depends on multiple genetic and environmental influences.

Manifestation
• Dyslexia is a set of processing difficulties that affect the acquisition of reading and spelling. The most commonly observed cognitive impairment in dyslexia is a difficulty in phonological processing (i.e. in phonological awareness, phonological processing speed or phonological memory). However, phonological difficulties do not fully explain the variability that is observed. Working memory, processing speed and orthographic skills can contribute to the impact of dyslexia.

Impact
• In dyslexia, some or all aspects of literacy attainment are weak in relation to age, standard teaching and instruction, and level of other attainments. Across languages and age groups, difficulties in reading and spelling fluency are a key marker of dyslexia.

Variance and co-occurrence
• Dyslexic difficulties exist on a continuum and can be experienced to various degrees of severity. Dyslexia can affect the acquisition of other skills, such as mathematics, reading comprehension or learning another language. Dyslexia frequently co-occurs with one or more other developmental difficulties, including developmental language disorder, dyscalculia, ADHD, and developmental coordination disorder.

Carroll, J., Holden, C., Kirby, P., Snowling, M. J., & Thompson, P.A. (2024)

When can dyslexia be diagnosed?

Dyslexia is typically only diagnosed only after a child is at least 7 years old. This allows time for quality first teaching to be delivered as well as interventions focused on the areas of development. While early identification of specific learning difficulties is important, allowing for this time enables an assessor to consider abilities in relation to the level of teaching and instruction that is noted in the definition of dyslexia.

Speech and language, hearing and sight difficulties can impact on early reading and writing development. Early identification of these can also be key in addressing early literacy difficulties.

If parents/carers have concerns about their child's progress and attainment in literacy, they should discuss these with the school's Special Educational Needs Co-ordinator (SENCO). Appropriate support should be put into place in line with the school's Special Educational Needs and Disabilities (SEND) policy which should advocate for early identification of SEND. Putting support into place at the right time can also help a specialist assessor to determine whether a diagnosis of dyslexia is appropriate. It is not necessary to have a formal diagnosis in order to access SEND support or to have access arrangements in place for exams as these are based on separate assessments and the normal way of working. However, a formal diagnosis of dyslexia by a specialist assessor or an educational psychologist can provide recommendations that support the education setting in selecting the most appropriate adjustments and interventions. A formal diagnosis is also valid for life which means it can be used to support applications for Disabled Students' Allowance at higher education and to seek adjustments in the workplace.