Cognitive Abilities in Neurodevelopmental Disorders

Question 1

What defines intellectual disability?

Answer 1

An IQ less than 70.
Impairment in intellectual functioning.
Impairment in everyday adaptive abilities (e.g. communication).

Question 2

What are floor effects?

Answer 2

This is when even the least difficult items on a test are too difficult for individuals. Adaptations to cognitive testing need to occur.

Question 3

Name 5 ways of adapting cognitive tests for people with ID.

Answer 3

Use easy read documents.
Give model responses.
Use simple test instructions.
Allow plenty of time for responses.
Use fewer/easier test items.

Question 4

Wha is the main incorrect assumption when considering cognitive development in atypical populations?

Answer 4

That cognitive development has a static trajectory which doesn’t change with age.
Developmental trajectories may be altered.

Question 5

Name the 3 main comparison populations for people with ID.

Answer 5

Chronological age matched controls. Weakness: does not account for global impairments in ID group.
Mental age matched controls. Weakness: does not account for importance of experience (e.g. children are sometimes used).
Control groups with another cause of ID. Usually used if ID is of unknown cause.

Question 6

Briefly state the Lanfranchi (2012) results focussing on the Working Memory Model.

Answer 6

Down syndrome: impairment in all verbal tasks (greater in dual vs single) - shows impairment in central executive function.
Impairment in visuospatial dual task not but single.
Relative strength in visuospatial abilities.
Both groups: Poor performance for within modality vs cross-modality.

Question 7

Describe the cognitive abilities in individuals with down syndrome.

Answer 7

Poor expressive language.
Spared receptive language.
Verbal more impaired than visuospatial memory.
Difficulties in executive functioning (e.g. planning).

Question 8

Describe brain development in individuals with down syndrome.

Answer 8

Smaller frontal lobe + hippocampal volumes.
Later developing areas are more affected.
Dorsal visual stream is relatively preserved - explains strength in visuospatial memory.
Ventral visual stream affected - explains weakness in visual object memory.

Question 9

What is the relationship between down syndrome and dementia?

Answer 9

There is a higher risk of developing Alzheimer’s disease along with an earlier onset (age 68 = 95% chance).
Memory changes, attention and executive function deterioration occur early.

Question 10

What causes Williams syndrome?

Answer 10

Deletion of 27 genes from one copy of chromosome 7.

Question 11

Which disorder correlates highly with Williams syndrome?

Answer 11

ADHD.

Question 12

Describe the cognitive abilities in individuals with Williams syndrome.

Answer 12

Poor visuospatial abilities.
Poor response inhibition (linked to ADHD) - hypersociable.
Good verbal abilities.
Good expressive language.

Question 13

Describe the brain differences in those with Williams syndrome.

Answer 13

Atypicalities in the parietal lobe + dorsal visual stream - explains visuospatial difficulties.
Large frontal areas.

Question 14

Which two tests did Vicari (2003) conduct on those with Williams syndrome?

Answer 14

Vicari tested for spatial span and visual span - two working memory tests.

Question 15

Briefly state the Vicari (2003) results.

Answer 15

Individuals will Williams syndrome had poor spatial span.

No difference in visual span.

Question 16

What causes Fragile X syndrome?

Answer 16

A repeated CGG sequence in the Fragile X mental retardation 1 gene on the X chromosome.

Question 17

Which two disorders correlate highly with Fragile X syndrome?

Answer 17

Autism + ADHD.

Question 18

Is Fragile X syndrome twice as common in boys or girls?

Answer 18

Boys.

Question 19

Describe the cognitive abilities in individuals with Fragile X syndrome.

Answer 19

Poor visuospatial abilities.
Poor verbal abilities.
Poor response inhibition (linked to ADHD).
Increased social anxiety + social avoidance.

Question 20

Describe the brain development in individuals with Fragile X syndrome.

Answer 20

Small frontal lobes.
Delayed maturation in the prefrontal cortex.
Altered development in the dorsal visual stream.

Question 21

Briefly state the Vicari (2005) results (cross-syndrome comparison study).

Answer 21

Williams syndrome: impaired visual spatial memory but not visual object learning.
Down syndrome: opposite.
There is a double dissociation between the two conditions - different cognitive profiles.

Question 22

Briefly state the Munir (2000) results (cross-syndrome comparison study).

Answer 22

Fragile X syndrome: impaired visuospatial memory, impaired central executive function, impaired verbal working memory (compared to controls only - FXS + DS were equal in this).
Down syndrome: impaired visuospatial memory (compared to controls only), impaired central executive function, impaired verbal working memory (compared to controls only - FXS + DS were equal in this).

Question 23

Briefly state the Cornish (2007) results (cross-syndrome comparison study).

Answer 23

Compared all three syndromes + one control group in a visual selective attention task, sustained attention task and an inhibition task.
Williams syndrome: made the most errors - explains selection attention difficulties.
Fragile X syndrome: most repetitions - explains inhibitory difficulties. Poorest inhibition performance.
Down syndrome: poorest selective attention performance.
No group differences in sustained attention!