Definitions
Definition of SpLD - Dyslexia (2025)
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.M., Holden, C., Kirby, P., Thompson, P.A. and Snowling, M.J. (2025). Toward a consensus on dyslexia: findings from a Delphi study.
Definition of a Specific Learning Difficulty in Mathematics (2025)
Features
A specific learning difficulty in mathematics is a set of processing difficulties that affects the acquisition of arithmetic and other areas of mathematics.
In dyscalculia, the most commonly observed cognitive impairment is a pronounced and persistent difficulty with numerical magnitude processing and understanding that presents in age related difficulties with naming, ordering and comparing physical quantities and numbers, estimating and place value.
Some individuals may not present with a specific cognitive impairment in numerical magnitude processing but have an equally debilitating specific learning difficulty (SpLD in mathematics) due to other processing difficulties. Difficulties in language, executive function (verbal and visuo-spatial working memory, inhibitory control) and visual-spatial processing may also contribute.
Impact
Mathematics is a very varied discipline. Difficulties with learning mathematics may present in specific areas (for example, basic calculation) or across of the mathematics studied by the individual in relation to age, standard teaching and instruction, and level of other attainments. Across education systems and age groups, difficulties in arithmetic fluency and flexibility and mathematical problem solving are key markers of a SpLD in mathematics. Persistent difficulties in mathematics can have a significant impact on life, learning and work. This may also have a detrimental impact upon an individual’s resilience to apply mathematical skills effectively.
Presentation
The presentation and developmental trajectory of a specific learning difficulty (SpLD) in mathematics depends on the interactions of multiple genetic and environmental influences. It will persist through life but may change in manifestation and severity at different stages.
A SpLD in mathematics frequently co-occurs with one or more of the following: attention deficit hyperactivity disorder (ADHD), dyslexia, developmental language disorder (DLD) and developmental coordination disorder (DCD).
Maths anxiety commonly co-occurs with a SpLD in mathematics but is not an indicator in itself.
Specific Learning Difficulties Assessment Committee (2025) Maths Difficulties and Dyscalculia Guidance: Guidance on Maths Difficulties published, 24 March.