Developmental disorders

Theories to explain dyslexia

Types of dyslexia

Developmental disorder

Present when aspects (cognition, speech, fine motor skills etc.) of child development are significantly delayed

Neurodevelopment disorder

Affect development of nervous system

Abnormal brain function can affect:

  • emotions
  • learning ability
  • self control
  • memory
  • ADHD
  • Specific Language Impairment
  • Intellectual disability
  • Cerebellar palsy
  • Epilepsy

Phonological deficit hypothesis
(Snowling, 1981)

People with dyslexia have:

  • poor phonological awareness and memory
  • structural deficit in brain
  • difficulty processing speech sounds

Visual deficit hypothesis
(Lovegrove, 1993)

Visual attention span deficit might contribute to developmental dyslexia

Phonological interventions showed reading performance improvement

Not much evidence though

Automatisation hypothesis
(Nicholson & Fawcett, 1990; 1994)

Broader view

  • inability to become completely fluent in cognitive and motor skills

Damage to cerebellum

Physical exercise can improve working memory and reading performance

Perform worse on rapid naming tasks

Phonological

Rapid naming

Double deficit

Surface

Developmental vs acquired

deficit in rapid naming and phonological skills

  • results in lowest reading performances

extreme difficulty reading and manipulation of basic sounds

difficulty naming thinks such as numbers, letters and colours when you see them

difficulty with whole word recognition, particularly words that don't sound how they are spelled

Acquired

  • e.g. result of stroke, head trauma
  • can diminish over time

Developmental

  • difficult reading, but intelligence unimpaired
  • life long condition

Developmental assessment

Dyslexia in non-alphabetic languages (Chinese)

Diagnosis is different

Phonological awareness doesn't play a part

Early identification

  • Differences identified by parents, teachers, health visitors
    • Delayed milestones, difficulty with motor and coordination skills

Screening test

  • standardised tool to detect developmental delays

Little development coordination disorder questionnaire (DCDQ)

  • children under 4

Development coordination disorder questionnaire (DCDQ)

  • children over 4