Normal and abnormal development

Question 1

Genetic disorders affecting development (RHS of the syllabus)

Answer 1

Downs
Williams
Fragile X syndrome

Question 2

Describe heterochronous developmental changes

Answer 2

Rise and fall of synaptic plasticity density differs in timing for different areas - for example, this was shown for visual, auditory and PFCs by Huttenolcher et al in 2002

Question 3

What is the key message of this segment?

Answer 3

That timing is of the essence

Question 4

What is the clinical relevance of developmental timing - understanding of paediatric brain injuries?

Answer 4

1. what are the effects of damaging areas crucial to cognitive functions later in life?
2. can the adult effects of damage be translated to understanding pediatric cases? [yes/no? hard question due to plasticity and different outcomes according to timing and affected functions]
3. does the response to insults vary across domains of functioning (e.g., language, spatial cognition, executive functions)?

Question 5

What is an example of a process that is less vulnerable to early brain damage than to later lesions, and that recovers for efficiently overall?

Answer 5

Expressive language

Question 6

Describe Bates 2001 - regarding LHD and RHD damage

Answer 6

A 2001 study of 38 children with congenital left hemisphere damage (LHD) or right hemisphere damage (RHD) were in the normal range for their age on all measures of lexicon and grammar.

There were no significant differences between children with LHD and RHD on any measure.

When LHD children were compared directly with LHD adults (aphasia) using age-corrected z scores, the children scored far better than their adult counterparts (Bates et al, 2001)

This provides evidence for the role of plasticity in preventing such functional losses

Question 7

Bates 1997 - language

Answer 7

children who suffered focal brain damage either prenatally or within the first 6 months of life, children with right hemisphere damage (RHD) show greater risk for delays in language comprehension (c.f. in adult in which left posterior injury to Wernickes area results in the same symptoms)

Question 8

Thal 1991 - language

Answer 8

children with left hemisphere damage (LHD) -in particular in left posterior hemisphere (LP+)- show greater risk for difficulties in language production (c.f. in adult where left anterior injury to Brocas area results in the same symptoms)

→ - expressive vocabulary for 12-16 months in LP+ and LP- children is very similar; however, expressive vocabulary falls behind in LP+ children between 17 and 35 months (LP+ cannot follow up while LP- learn)

Question 9

What may influence prenatal and postnatal development? (from intro)

Answer 9

Prenatal development – disrupted by migration errors (lissencephaly = lack of migration of neurons during 12-14 weeks such that gyri and sulci fail to form: psychomotor retardation, seizures etc), hormonal abnormalities (thyroid hormones, corticosteroids), maternal stress and age, maternal drug and alcohol addiction, and environmental toxins (lead, radiation, trauma)

Postnatal development – disrupted by errors affecting refinement of synapses (e.g. fragile X syndrome), birth complications (anoxia, premature birth) cerebral infections, environmental toxins and environmental experience (eg sensory deprivation)

Question 10

In contrast with the apparent resilience of language development, describe how visuospatial functions are affected by early injuries

Answer 10

• Children with early LHD have difficulties with processing and producing both local and global aspects of their visual environment, when tested with COMPLEX NAVON FIGURES (large recognizable shapes, such as letters, composed of copies of a smaller different shape).
• Children with early RHD have difficulties with global aspects of these tasks only (Stiles et al., 2005, 2006)

Question 11

Describe how executive function is affected by early injuries

Answer 11

• 38 children with frontal lobe lesions, tested on a variety of tasks, some tapping executive functions (e.g., Tower of London (referring specifically to deficits in planning; the test consists of two poards with pegs and beads with different colours; the examiner uses the beads and boards to present the patient with problem solving tasks), Verbal Fluency tests):

cases sustaining insults prenatally performed more poorly across the board on executive tasks and children with lesions between 7 and 9 years of age did best.

Outcome for children with lesions in early childhood and after 10 years of age was task-dependent (e.g., non-verbal; verbal) and generally poorer than controls (Jacobs, Harvey & Anderson, 2007).

Question 12

What are the childhood onset developmental disorders

Answer 12

Attention deficit/ hypperactivity disorder (ADHD)

Autistic spectrum disorders (ASD)

Question 13

Describe the introduction of childhood onset developmental disorders

Answer 13

Unlike acquired brain injuries, these are identified by their behavioural characteristics, and may be heterogeneous in aetiology;

the age of diagnosis and progression may differ.

It is likely that there are core neurocognitive deficits associated with these.

Question 14

How has ADHD got bad press?

Answer 14

Often associated with mis-behaviour in children, ADHD often gets bad press - e.g. in 2007 an article was published headlined ADHD was the result of bad parenting. Alternativley bad press comes from ADHD being said to be genetically determined - Particularly because “Findings provide genetic evidence of an increased rate of large CNVs in individuals with ADHD and suggest that ADHD is not purely a social construct.” (Williams et al., 2010, Lancet)

Question 15

Diagnosing ADHD

Answer 15

DSM-IV (American Psychiatric Association) ADHD diagnostic criteria:
A. Symptoms in 2 categories: 1 (inattention) & 2 (hyperactivity)
Children must exhibit six (or more) in either category
Symptoms must have persisted for at least 6 months to an extent that is inconsistent for developmental level (based on this classified into inattentive, combined, or hyperactive type);

B. Some symptoms are present before the age of 7 (updated to 12 in DSM-V);

C. Symptoms are exhibited in two or more settings (e.g. school and home);

D. Clear evidence of clinically significant impairment in social or scholastic function;

E. Symptoms do not occur solely in the course of, or cannot be better accounted for by, another disorder

Question 16

Prevalence of ADHD

Answer 16

3-5% in schoolchildren

Question 17

Inattention symptoms

Answer 17

Has difficulty sustaining attention in tasks or play

Fails to give close attention to details

Does not seem to listen when spoken to

Does not follow through on instructions

Has difficulty organising tasks/activities

Avoids tasks that require mental effort

Loses things necessary for tasks

Is easily distracted by external stimuli

Is forgetful in daily activities

Question 18

Hyperactivity symptoms

Answer 18

Fidgets with hands/feet/squirms in seat

Leaves seat when sitting is expected

Runs about when inappropriate

Has difficulty playing or engaging in leisure activities quietly

Is always ‘on the go’

Talks excessively/blurts out answers

Has difficulty awaiting turns

Interrupts or intrudes on others (e.g., butts into conversations or games)

Question 19

Describe different types of ADHD

Answer 19

• ADHD exists in a inattentive type (difficulty sustaining attention in tasks or play) and in a hyperactive type (fidgets with hands/feet/squirms in seat) or in a combined type (features of both types); the combined type is way more frequent, and at present the tendency is not to talk about pure types but rather a variability in the features of each type in combination; however, there are few cases displaying features of just one type

Question 20

Describe the cognitive theory that executive function accounts for all ADHD impairments

Answer 20

inhibition deficit (inability to inhibit a prepotent response) affects:

• working memory (acting on events held in memory)
• self-regulation (emotional, self-control)
• speech internalization (description and reflection)
• reconstruction (analysis and synthesis of behaviour)

Question 21

Discuss ADHD neuroscience

Answer 21

• ADHD present anatomical differences (longitudinal changes in gray matter, density of connectivity) and functional differences in fMRI and electrophysiology (changes in frontostriatal circuit involving dopamine -

effectiveness of dopamine reuptake inhibitors like methylphenidate (Ritalin)- dopamine deficiency might be a factor

noradrenaline also likely to be involved -
effectiveness of noradrenaline reuptake inhibitors like atomoxetine-)

Question 22

Discuss ‘caution: sensitivity and selectivity’ with regard to ADHD

Answer 22

• Inhibition deficits characterize many, but not all children with ADHD, and are also present in other disorders (Oosterlaan et al, 1998].
• Inhibition difficulties: how do they account for inattention symptoms? (e.g. Huang-Pollock et al, 2006)

• Other problems that could account for ADHD include:
o Working memory difficulties (Lui and Tannock, 2007)
o Sustained attention difficulties (Manly et al, 2001)
o Motivational difficulties (Solanto et al, 2001)

Question 23

Beyond executive deficits in ADHD

Answer 23

1. Distinct cognitive processes and neural pathways maybe involved in inhibition deficits and the other factors that characterise children with ADHD, notably motivational differences (Castellanos et al, 2006)
2. There is evidence of interactions between motivational factors and inhibitory deficits (e.g. Liddle et al, 2011)
3. Need to think about separable but interacting networks beyond frontal regions (Castellanos & Proal, 2012; Cortese et al, 2012)
4. Abandon the “core deficit” approach to ADHD (Castellanos et al, 2006)

Question 24

Management of ADHD

Answer 24

Management of ADHD – combination of medication, behaviour therapy, lifestyle changes and counselling. Drugs include Ritalin (methylphenidate) or non-stimulant drugs e.g. atomoxetine. Medications are not recommended for use in pre-school age children, as long-term usage effects are unknown. There is also a lack of evidence comparing how effective these drugs are.

Question 25

Describe ASD diagnosis

Answer 25

DSM-IV diagnostic criteria:

At least two symptoms of social impairment:

a. Marked impairment in use of non-verbal behaviours (e.g. eye-contact)
b. Failure to develop age-appropriate peer relations;
c. Lack of spontaneous sharing of enjoyment, interest or achievements with other people
d. Lack of social or emotional reciprocity

At least one symptom of communication impairment:

a. Delay or lack of spoken language
b. If speech is present, marked impairment in initiating or maintaining conversation
c. Stereotyped or repetitive use of language
d. Lack of spontaneous/varied pretend play

At least four symptoms of restricted, stereotyped, and repetitive behaviours (narrow interests, adherence to non-functional routines, motor stereotypes, persistent preoccupation with parts of objects etc).

Question 26

Describe ASD and physical-causal vs mental-causal

Answer 26

Many children with autism are able to sequence the pictures of a physical-causal story where there is a clear progression in the story and a physical event occurs to lead to the conclusion. They can not however sequence the pictures of a ‘mental-causal story’ where the thoughts of another individual must be considered to get to the conclusion; there is a core deficit on thinking about and understanding other peoples minds

Question 27

Describe Baron-Cohen (1985) - Sally Anne task?

Answer 27

The patient is shown a series of pictures, where Sally puts a ball in a basket, exits the room, Anne then moves the ball to her box, and Sally re-enters. They are then asked:

• The false belief question: “Where will Sally look for her marble?”
• The memory question: “Do you remember where Sally put the marble at the beginning?”
• 3-year-olds do rather poorly – “Sally will look in the box”
• 4-year-olds: “Sally will look in the basket”
• 80% of children with autism fail

Question 28

Happe (1995) - Sally Anne task?

Answer 28

In general, children with ASD fail the task at much older ages than typically behaving children

Question 29

Discuss ‘caution: sensitivity and specificity’ witht regard to ASD?

Answer 29

• Not all children who fail the S/A task have autism

* Not all children with autism fail simple tasks like S/A

Question 30

Describe other accounts of ASD?

Answer 30

Other accounts of disorder are; executive difficulties (inhibiting true beliefs), executive functions predict later mentalizing abilities in ASD; children with ASD have weak central coherence; this accounts for strengths in some ASD, e.g. in finding embedded figures; there is abandon of single core deficit account - it is a multiple-hit disease

There is great variability - a spectrum of disorder and dysfunction across the different areas of deficit

Question 31

Summarise ADHD

Answer 31

• Initial cognitive and neuroscientific focus was on executive
  deficits and fronto-striatal circuitry
• This does not account for all features of the disorder
• Neuroscience tools and techniques have advanced the study
  of networks in ADHD, arguing against a single core deficit
  account

Question 32

Summarise ASD

Answer 32

• Initial focus on mentalising difficulties with false-belief tasks
• This does not account for all features of the disorder
• The notion of multiple dimensions and deficits