Neurodevelopmental Disorders

3 famous ones

1. Dyslexia

2. ADHD

3. Autism Spectrum Disorder

Symptoms associated with neurodevelopmental disorders

• hyperactivity

• Motor impairments

• Emotional liability

• Attention dirsoders

• Impulsivity

• Learning disabilities

2 types of neurodevelopmental disorders

1. Language related

2. Non language related

Reading

• Depends on phonological skills then graphemic skills as we become better readers

• Memory to store words, meanings and ways of combining them

Phonological reading

decoding the sounds of words

Graphemic reading

word is memorized

Skills required for reading

• letter identification

• Phonological, graphemic and sequencing skills

• Short term memory

Causes of reading disabilities

• impairments with speech sounds awareness (phonological)

• Attention cannot be easily shifted

• Sensory deficiency, longer time to discriminate tones

Temple and colleagues

• dyslexics have a deficit in processing rapidly changing sounds

• fMRI showed less activation in the left prefrontal cortex

Non language related disorders

• Hydrocephalus

• Cerebral palsy

• Fragile-X syndrome

• Fetal alcohol spectrum disorder

• Attention deficit hyperactivity disorder

• Autism spectrum disorder

Hydrocephalus

• increased volume of CSF

• Caused by obstruction of flow or overproduction of CSF

• Can be treated by insertion of value to drain fluid

Cerebral Palsy

• motor abnormalities and sometimes cognitive impairments

• Lesions in corticospinal tracts, basal ganglia, brainstem and cerebellum

Fragile-X syndrome

• facial abnormalities (long face, large ears, flat feet)

• Mild to severe mental disabilities

• May be associated with attention deficits, hyperactivity, anxiety

Science of fragile-x syndrome

• CGG (cytosine, guanine) triplet repeat on X chromosome

• Poorly formed dendritic spines

• Thin cortex and unusually small caudate nucleus

• Increased ventricular size

Fetal alcohol spectrum disorder

• small barn, abnormal gyri, abnormal clusters of cells

• Learning disabilities, low IQ, hyperactivity and social problems

Attention Deficit/Hyperactivity disorder due to

• brain damage

• Encephalitis

• Genetics

• Food allergies

• High lead concentrations in environment

Autism

• children with no obvious focal cerebral disease

• Children display impaired social intraction, bizarre and narrow range of interests, language abnormalities

• Preserved intellect

Brain abnormalities of autism spectrum disorder

• Larger head and brain size than normal

• Failure of the von Economo neurons to develop normally

• Brainstem development abnormalities

Asperger’s sydrome

• less serene than autism

• Hyperlexia (reading abilities)

Savant syndrome

• narrow range of special abilities

• Common triad is retardation, blindness and musical genius