Brain and behaviour spring term lecture 1: neuroscience of developmental disorders.
Introduction, approaches and DLD
What are developmental disorders?
Key Terminology
Specific learning disabilities (e.g., dyslexia, mathematical disorder)
Intellectual Disabilities (e.g., Down syndrome)
Mental health / Psychiatric disorders (e.g., ADHD, conduct disorder)
Autism spectrum disorders
Speech language and communication difficulties (e.g., developmental language
disorder)
Special Educational Needs
As of October 2018 (Department for Education statistics):
1.2 million children, or about 15% of all students in England, have some kind of SEN.
About 253,000 have severe problems that require SEN statements or education
health and care plans
Individuals with SEN are 4x more likely to have an anxiety disorder
This shows you data published by the DFE from 2017. You can see that of the 1.2
million who have SEN support of some level, most have specific and moderate
learning difficulties (like dyslexia), or social/emotional/mental health and speech
language and communication needs. Of the 250,000 who have statements or EHC
plans, most have autism spectrum disorder.
Approaches to studying developmental disorders
Typical Development as Context
“the only way to understand developmental disorders is to relate them to studies of
typical development”
Hulme & Snowling, 2009, p 19
And visa versa e.g. dyslexia and typical reading development
Development is a process
Need to study the development as a process, not just as an end product.
Wolff et al (2012)
measured white matter tract integrity by capturing how water molecules move
through fibres in the brain.
92 infants tested at 6, 12, 24 months.
At 6 months, infants with autism at 24 months had higher white matter integrity
than infants without autism.
At 12 months, no group differences.
By 24 months, the 6-month-old pattern had reversed.
Development Timing
, Developmental Timing may be key.
Atypical populations often experience unusual timings, which affect them in at least
two ways:
1. Altering the environmental input
2. Misaligns growth across domains
E.g., Estes et al; (2015) found that infants later diagnosed with ASD had motor
impairments at 6 months, which preceded deficits in communicative skills at 12
months. They argued that motor delays might reduce gesture use, which hampers
language learning opportunities.
Another issue to be aware of is how development is impacted by timing. Atypical
populations often experience unusual timing of key developmental milestones,
which might affect them in at least two ways. It will alter the environmental input
they get in comparison to a child who is developing typically (e.g., a child who is late
to walk will receive a different view of the world than a child who is more mobile),
and this leads to misaligned growth across domains (e.g., a child who is late to walk
might still be developing the desire to interact with others at the typical rate,
meaning a discrepancy/conflict between these two domains). An example of taking
timing into account is provided in a study by Estes et al (2015) – they found that… so
a misalignment between motor and language development may cause language
learning difficulties.
Multiple Methods are important
Sometimes behavioural performance can be equivalent between groups, but the
brain processes supporting performance might be different.
E.g., Massand et al (2013) – both adults with ASD and control adults could
remember new words to the same degree, but EEG responses to old versus new
words occurred in different areas with different intensities (i.e., anterior regions for
TD, but parietal and posterior regions for ASD).
This is important as it impacts what we need to do to help and support those with
developmental disorders. One method won’t work for all if different things are
causing what looks like the same problem.
Common Developmental Designs
The three study designs that are most often used:
Cross-sectional Studies
1. Examining Group Difference: Characterising particular groups/Identifying
areas of focus for intervention/Developing hypotheses for causal theories
2. Examining changes with age: Quick/Associational
Cross-sectional means carrying out a study at a single point in time. These studies
tend to come in one of two varieties. Group difference studies are where researchers
take one group, say with autism, and another group without, and compares their
performance on a particular task. This study compares infectious yawning in children
without autism on the left and children with autism on the right, both in response to
seeing somebody else yawning and in a control condition (where they saw people
who were not yawning). You can see that children with autism showed a lower
number of yawns when viewing others yawning. Such studies are useful at
characterizing the profiles of different groups. And can be useful to identifying areas
for focus in intervention (e.g., studies finding a phonological deficit in groups of
children with dyslexia led to intervention research that aimed to improve
Introduction, approaches and DLD
What are developmental disorders?
Key Terminology
Specific learning disabilities (e.g., dyslexia, mathematical disorder)
Intellectual Disabilities (e.g., Down syndrome)
Mental health / Psychiatric disorders (e.g., ADHD, conduct disorder)
Autism spectrum disorders
Speech language and communication difficulties (e.g., developmental language
disorder)
Special Educational Needs
As of October 2018 (Department for Education statistics):
1.2 million children, or about 15% of all students in England, have some kind of SEN.
About 253,000 have severe problems that require SEN statements or education
health and care plans
Individuals with SEN are 4x more likely to have an anxiety disorder
This shows you data published by the DFE from 2017. You can see that of the 1.2
million who have SEN support of some level, most have specific and moderate
learning difficulties (like dyslexia), or social/emotional/mental health and speech
language and communication needs. Of the 250,000 who have statements or EHC
plans, most have autism spectrum disorder.
Approaches to studying developmental disorders
Typical Development as Context
“the only way to understand developmental disorders is to relate them to studies of
typical development”
Hulme & Snowling, 2009, p 19
And visa versa e.g. dyslexia and typical reading development
Development is a process
Need to study the development as a process, not just as an end product.
Wolff et al (2012)
measured white matter tract integrity by capturing how water molecules move
through fibres in the brain.
92 infants tested at 6, 12, 24 months.
At 6 months, infants with autism at 24 months had higher white matter integrity
than infants without autism.
At 12 months, no group differences.
By 24 months, the 6-month-old pattern had reversed.
Development Timing
, Developmental Timing may be key.
Atypical populations often experience unusual timings, which affect them in at least
two ways:
1. Altering the environmental input
2. Misaligns growth across domains
E.g., Estes et al; (2015) found that infants later diagnosed with ASD had motor
impairments at 6 months, which preceded deficits in communicative skills at 12
months. They argued that motor delays might reduce gesture use, which hampers
language learning opportunities.
Another issue to be aware of is how development is impacted by timing. Atypical
populations often experience unusual timing of key developmental milestones,
which might affect them in at least two ways. It will alter the environmental input
they get in comparison to a child who is developing typically (e.g., a child who is late
to walk will receive a different view of the world than a child who is more mobile),
and this leads to misaligned growth across domains (e.g., a child who is late to walk
might still be developing the desire to interact with others at the typical rate,
meaning a discrepancy/conflict between these two domains). An example of taking
timing into account is provided in a study by Estes et al (2015) – they found that… so
a misalignment between motor and language development may cause language
learning difficulties.
Multiple Methods are important
Sometimes behavioural performance can be equivalent between groups, but the
brain processes supporting performance might be different.
E.g., Massand et al (2013) – both adults with ASD and control adults could
remember new words to the same degree, but EEG responses to old versus new
words occurred in different areas with different intensities (i.e., anterior regions for
TD, but parietal and posterior regions for ASD).
This is important as it impacts what we need to do to help and support those with
developmental disorders. One method won’t work for all if different things are
causing what looks like the same problem.
Common Developmental Designs
The three study designs that are most often used:
Cross-sectional Studies
1. Examining Group Difference: Characterising particular groups/Identifying
areas of focus for intervention/Developing hypotheses for causal theories
2. Examining changes with age: Quick/Associational
Cross-sectional means carrying out a study at a single point in time. These studies
tend to come in one of two varieties. Group difference studies are where researchers
take one group, say with autism, and another group without, and compares their
performance on a particular task. This study compares infectious yawning in children
without autism on the left and children with autism on the right, both in response to
seeing somebody else yawning and in a control condition (where they saw people
who were not yawning). You can see that children with autism showed a lower
number of yawns when viewing others yawning. Such studies are useful at
characterizing the profiles of different groups. And can be useful to identifying areas
for focus in intervention (e.g., studies finding a phonological deficit in groups of
children with dyslexia led to intervention research that aimed to improve
