10: Neurodevelopmental Disorders Flashcards
What is intellectual disability?
IQ of less than 70
Impairment in intellectual functioning and everyday activities
Large variation
How do cognitive tests have to be adapted for people with intellectual disabilities?
Easy read documents Model responses Fewer items Simple task instructions More time on responses
What is the floor effect?
Where the least difficult items on a test are still too difficult for some people
What comparison populations can we use when studying intellectual disability?
Chronological age: People of the same age
Mental age: Those of the same mental abilities
What is a chronological age matched control group?
A control group of typically developing people of the same age
What is a mental age matched group?
Typically developing people with the same cognitive abilities
Not always the same age
What causes down syndrome?
Trisomy of chromasome 21
What is the prevelance of down syndrome?
6.6 people per 10,000
What did Pennington find about people with down syndrome?
They have impaired memory
What did Lanfranchi find about peopel with down syndrome?
They have a general impairment of executive functioning capabilities
How do the cognitive abilities of those with down syndrome compare with the normal population?
Poor expression of langiage
Impaired verbal memory
Difficulties in executive functioning
How is the brain of peope with down syndrome different?
Smaller frontal lobe and hippocampus
Ventral visual stream is affected which leads to poor object memory
Later developing areas are more affected
What is the link between dementia and down syndrome?
Higher risk with an earlier onset
What percentage of people with down syndrome go on to develop dementia?
95%
What causes Williams syndrome?
Deletion of 27 genes from a copy of chromosome 7
What is the prevelence of Williams syndrome?
0.6 per 10,000 people
What are the cognitive abilities of those with WIlliams syndrome?
Por visuospatial abilities
Poor inhebition
Hyper-sociable
How are the brains of people with Williams syndrome different?
Large frontal areas
Atypical parietal lobe and dorsal visual stream
What did Vicari find about people with Williams syndrome?
They showed poor spatial span but no difference in visual span
What causes fragile x syndrome?
Repeted CGG sequence in the gragile x mental retardation gene in the X chromosome
What is the prevelance of fragile x syndrome?
- 5 per 10,000 in males
1. 25 per 10,000 in females
What are the cognitive abilities of people with fragile x syndrome?
Poor verbal and visuospatial activities
Decrease in response inhebition
Increased social anxiety
How are the brains of people with fragile x syndrome different from normal?
Small frontal lobe
Delayed maturation of the prefrontal cortex
Altered development of the dorsal stream
