Specific learning disability

Specific Learning Disorders

• Specific learning disorders can be associated with emotional problems, but development in other areas is not affected.
• The DSM-5 uses the term specific learning disorder (SLD) to describe a number of different disorders of language and not the term dyslexia.

Reading Disorder

• Reading disorder is grouped with other learning disorders in DSM-5.
• There are two different, but commonly occurring, reading disorders in children: dyslexia and reading comprehension disorder.
• Dyslexia refers to a difficulty in learning to decode, leading to poor appreciation of the spelling patterns of words and their pronunciation.
• Errors in reading and spelling include omissions, substitutions, or distortions of words, slow reading, long hesitations, and reversals of words or letters.
• Reading comprehension disorder: children with this disorder show a contrasting pattern, where they are able to read aloud accurately but have difficulty understanding what they have read.

Dyslexia

• Estimates of the presence of dyslexia in English-speaking countries range from 3% to 10% in school-aged children.
• Typically, the spelling difficulties in people with dyslexia are more resistant to remediation than their reading difficulties.
• People with specific reading difficulties are more often male and are more likely to have minor neurological abnormalities, and to come from socially disadvantaged homes.
• Sensory impairments are common; for example, some auditory processing tasks, especially frequency discrimination, present in up to 30-40% of children with dyslexia.

Aetiology of Reading Disorders

• Reading is a complex skill that depends on more than one psychological process and is learned in several stages.
• The aetiology of reading disorders is varied and depends on genetic and environmental factors.
• The predominant cognitive explanation of dyslexia is that it arises from a phonological deficit - a problem in processing the speech sounds of spoken words.
• Another theory focuses on naming speed measured by rapid automatized naming tests (RAN).

Disorders of Communication, Speech, and Language

• Communication is the transmission of information using a common signalling system, and language is a form of communication humans use to assist in communication.
• Language is a complex formal system that makes use of sounds and words in rule-governed ways to convey an infinite number of meanings.
• The process by which language is acquired is complex and is still not fully understood.
• Specific language impairment appears to be a relatively common disorder.
• Estimates show around 7% in kindergarten children.
• There are high levels of comorbidity with reading disorders, motor coordination, general learning disorders, and ADHD.

Causes of Speech and Language Disorder

• The causes of language impairment remain poorly understood.
• Children appear to have pronounced problems in word learning (vocabulary knowledge), grammar learning, and phonology.
• A minority might have another primary disorder, such as intellectual disability, hearing problems, cerebral palsy, and ASD.
• Social deprivation can cause mild delays in speaking or add to the effects of the other causes.
• There is a genetic contribution, with mutations in a gene called FOXP2 causing some cases of severe language disorder.

Classification

• The classification differs in some ways between ICD-10 and DSM-5.
• ICD-10 uses the title 'specific developmental disorders of speech and language', whereas DSM-5 has the wider title 'communication disorders'.
• Three disorders appear in both classifications, although with some differences in nomenclature.

Speech Sound Disorder (Specific Speech Articulation Disorder)

• In this condition, accuracy in the use of speech sounds is below the level appropriate for the child's mental age, but language skills are normal.
• Errors in making speech sounds (phonemes) are normal in children up to the age of about 4 years, but by the age of 7 years most speech sounds should be normal.
• By age 12 years nearly all speech sounds should be made normally.
• Children with specific speech articulation disorder make errors of articulation so severe that it is difficult for others to understand their speech.

Language Disorder

• Language disorders are persistent difficulties in the acquisition and use of language across modalities.
• It can include issues with vocabulary, sentence structure, and discourse.
• The prevalence of language disorder depends on the method of assessment, but a rate of 1-5% of children has been proposed.
• About 50% of children who meet the DSM-5 criteria develop normal speech by adulthood, while the rest have persistent difficulties.

Acquired Epileptic Aphasia (Landau-Kleffner Syndrome)

• This is a rare disorder where a child who previously developed normally loses both receptive and expressive language, but maintains general intelligence.
• About 20% of cases are caused by mutations in the GRIN2A gene, which codes for a subunit of the NMDA glutamate receptor.
• The prognosis is variable; two-thirds of children experience a receptive language deficit.

Mathematics Disorder (Specific Arithmetic Disorder)

• The DSM-5 defines this disorder as a specific learning disorder which is also known as dyscalculia.
• The ICD-10 defines this disorder as specific arithmetic disorder.
• This disorder is typically defined as a difficulty in learning mathematics that is out of line with other aspects of a child's development.
• The difficulties are often evident from the time a child first attempts to learn to count.
• This may lead to secondary emotional difficulties when the child attends school.

Motor Learning Disorder

• Some children have delayed motor development, which results in clumsiness in school work or play.
• In ICD-10, this condition is called specific developmental disorder of motor function.
• It is also known as clumsy child syndrome or specific motor dyspraxia.
• The child can carry out all normal movements, but coordination is poor.

Social (Pragmatic) Communication Disorder

• The introduction of this category of disorder in DSM-5 is predominantly as a result of changes to the diagnostic criteria for ASD.
• This category is used for children with persistent difficulties in the social use of verbal and non-verbal communication.
• Four key areas of deficit need to be present for a diagnosis:
  • Using communication for social purposes (greetings);
  • Changing communication to match context or needs of the listener;
  • Following rules for conversation (turn-taking);
  • Understanding what is not explicitly stated and non-literal or ambiguous meanings.