The British Dyslexia Association (BDA)  provides the following definition for dyslexia:
Dyslexia is a specific learning difficulty that mainly affects the development of literacy and language related skills. It is likely to be present at birth and to be life-long in its effects. It is characterised by difficulties with phonological processing, rapid naming, working memory, processing speed, and the automatic development of skills that may not match up to an individual’s other cognitive abilities. It tends to be resistant to conventional teaching methods, but its effect can be mitigated by appropriately specific intervention, including the application of information technology and supportive counseling.
Developmental Co-ordination Disorder (DCD)
The SASC-STEC September 2013 defines dyspraxia as:
Developmental Co-ordination Disorder (DCD), also known as Dyspraxia in the UK, is a common disorder affecting fine or gross motor co-ordination in children and adults. This lifelong condition is formally recognised by international organisations including the World Health Organisation. DCD is distinct from other motor disorders such as cerebral palsy and stroke and occurs across the range of intellectual abilities. Individuals may vary in how their difficulties present; these may change over time depending on environmental demands and life experience.
An individual’s co-ordination difficulties may affect participation and functioning of everyday life skills in education, work and employment. Children may present with difficulties with self-care, writing, typing, riding a bike and play as well as other educational and recreational activities. In adulthood many of these difficulties will continue, as well as learning new skills at home, in education and work, such as driving a car and DIY. There may be a range of co-occurring difficulties, which can also have serious negative impacts on daily life. These include social and emotional difficulties as well as problems with time management, planning and personal organisation and these may also affect an adult’s education or employment experiences.
DYSCALCULIA is a specific learning difficulty with mathematics, primarily arithmetic. It was defined in a UK Government document in 2001 as: ‘Dyscalculia is a condition that affects the ability to acquire mathematical skills. Dyscalculic learners may have a difficulty understanding simple number concepts, lack an intuitive grasp of numbers, and have problems learning number facts and procedures Even if they produce a correct answer or use a correct method, they may do so mechanically and without confidence.’
It is defined in the USA (Diagnostic and Statistical Manual of Mental Disorders, 2013) as:
‘Difficulties in production or comprehension of quantities, numerical symbols, or basic arithmetic operations that are not consistent with the person’s chronological age, educational opportunities, or intellectual abilities.’