Dyslexia refers to a specific deficit in the acquisition of reading. Dyscalculia refers to a specific deficit in the acquisition of arithmetic skills. The prevalence rates for these disorders are four to seven percent and are often comorbid.

The common deficit account states that in the case of comorbid dyscalculia and dyslexia, it may be caused by phonological-verbal deficits. Dyscalculia without reading difficulties may be related to a different cognitive profile. Reading difficulties seem to aggravate rather than cause math difficulties.

The domain-specific cognitive deficit account states that dyscalculia and dyslexia have two separable cognitive profiles. This means that a phonological deficit would underlie dyslexia whereas a deficit in the cognitive representation of numerosity underlies dyscalculia.

There are three subcomponents of phonological processing that are typically deficient in people with dyslexia:

• Phonological awareness
  This refers to the ability to

Children with mathematical difficulties have particular impairments in understanding and processing numerical magnitudes. The defective number module hypothesis states that a highly specific deficit of an innate capacity to understand and represent quantities leads to difficulties in learning number and arithmetic. The access deficit hypothesis states that mathematical difficulties originate from impairments in accessing numerical meaning (i.e. their quantity) from symbols rather than from difficulties in processing numerosity.

Infants and young children are able to understand and manipulate numerical magnitude information by means of non-symbolic representations (e.g. discriminate between large sets of dots). Non-symbolic representations are characterized by a distance effect. This holds that the numerical difference (i.e. distance) between two sets that need to be compared is small, performance is slower and less accurate than when the distance is large (e.g. comparing 7 to 442 is easier than comparing 23 to 22). This effect may occur due to

Lower order processes refer to the level of letter and word recognition. Higher order processes refer to the comprehension of the content of text. Efficient word recognition processes are necessary but not sufficient for the successful execution of reading tasks. It allows the reader to allocate optimal attention to the interpretation of meanings communicated in the text but are not sufficient because text comprehension comprises other components as well (e.g. general knowledge).

It is possible that reading comprehension in the second language (i.e. L2) is the application of higher order reading strategies of the first language on the second language. It is also possible that linguistic knowledge of the second language is important for a satisfactory level of text comprehension. Next, it is also possible that the efficient or automized processing of linguistic information is important for successful reading comprehension in the second language. This would

Children with mild to borderline intellectual disabilities (MBID) have problems with adaptive functioning in social situations and in peer relations. They are rejected more often and have problems building social relations. They show more aggressive behaviour, partially because of the lack of adequate social skills. Comorbidity is also common in MBID. Youth with MBID is overrepresented in the criminal justice system.

To show socially adaptive behaviour, complex social skills are needed. Adaptive social behaviour depends on social information processing (SIP). This refers to the way social information is encoded (1), behaviour of others is interpreted (2), own emotions are regulated (3), responses to the problem situation are generated, selected and enacted (4). Youth with MBID typically encode more negative information (1), have less assertive but more submissive problem solving skills (2) and have more aggressive problem solving skills (3).

Cognitive limitations may explain differences in