Developmental Neuropsychology | The Book
Week 1 | Biopsychosocial model / Principles of child neuropsychological assessment
Chapter 1 | Child Neuropsychology, theory and practice
Child neuropsychology, or paediatric neuropsychology, refers to the study of brain–
behaviour relationships within the context of an immature but rapidly developing brain and
the implementation of the knowledge gained into clinical practice.
Child neuropsychology: historical perspectives
Non-verbal learning disability (NVLD)
In the 1980s, Rourke (1988; 1989; 1995) described his clinically driven notion of
NVLD to account for a consistent pattern of neurobehavioural deficits observed in children
with a history of early, generalised cerebral dysfunction resulting from brain insult occurring
during the perinatal period or in infancy. The hallmark characteristics of NVLD include: (i)
bilateral tactile–perceptual deficits, more marked on the left side of the body; (ii) impaired
visual recognition and discrimination and visuospatial organisational deficiencies; (iii)
bilateral psychomotor coordination problems, more marked on the left side of the body; and
(iv) difficulties managing novel information. Children with NVLD may also demonstrate a
range of intact skills, primarily within the auditory/verbal domain. Rourke lists these as: (i)
simple motor skills; (ii) auditory perception; (iii) rote learning; (iv) selective and sustained
attention for auditory–verbal information; (v) basic expressive and receptive language; and
(vi) word reading and spelling.
Developmental stage at insult and cognitive outcome
The second influential theory for the child neuropsychology field has been proposed
by Maureen Dennis (1989), based on her extensive research into child brain disorders,
including traumatic brain injury and spina bifida. Dennis’ ‘heuristic’ does not propose a
specific neurological mechanism for her theory, although other researchers have offered
possible biological explanations. Rather, it focuses primarily on age/developmental stage at
time of insult and progression in cognitive skills with time since insult. Her heuristic describes
the impact of brain damage on language development. She divides skill development into
several levels: (i) emerging, where an ability is in the early stages of acquisition, but not yet
functional; (ii) developing, where a capacity is partially acquired but not fully functional; and
(iii) established, where abilities are fully matured.
Child cognitive and socio-emotional function: the ‘psych’ dimension
Neurological correlates
Recent advances in the social neurosciences have facilitated better understanding of
the biological bases of these behaviours and social skills. In particular, the seminal work of
Adolphs in documenting the ‘social brain network’ has provided a blueprint (albeit based
primarily on adult data) describing the primary brain regions and functional neural network
involved in socio-emotional processing. The social brain network includes the superior
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,temporal sulcus (STS), fusiform gyrus (FG), temporal pole (TP), medial prefrontal cortex
(mPFC), frontal pole (FP), orbitofrontal cortex (OFC), amygdala, insula, temporoparietal
junction (TPG) and cingulate. Socio-affective skills subsumed by this net- work are
vulnerable to disruption from early brain injury and are shown to elevate risk for later
maladaptive behaviour.
Conclusions
The dimensions of knowledge important to child neuropsychology – neurologic,
cognitive, socio-emotional, environmental – must each be incorporated into future theory in
the child neuropsychology field. Current theoretical perspectives represent a significant
progression over the past 20 years, when understandings were based primarily on adult
models of brain lesions. Today, developmental perspectives extend our breadth of knowledge,
but continue to fall short in explaining the complexities of interruption to a system in a rapid
state of development. There continues to be an unacceptably high degree of unexplained
variation in outcome following early childhood brain insult. The challenge is to improve
predic- tion of outcome by measuring the interacting influences of neural, cognitive and
psychosocial parameters and their ever-changing matrix through childhood.
Chapter 3 | Cognitive and Social Development
Within the cognitive development literature, there is ongoing debate with respect to
the mechanisms underpinning the maturation of cognitive abilities. Some theorists support
domain-specific models and others argue for a more domain-general framework. The domain-
specific approach, often applied to language development, is based on a ‘modular’ or
‘localisationist’ approach, with individual cognitive skills seen as developing according to a
unique time- table and set of rules. In contrast, the domain-general view argues that the
emergence of cognitive skills follows a more general blueprint, where the development of
specific skills is dependent on a range of cognitive processes, more in keeping with the
emergence of functional neural networks. Consistent with this domain-general perspective,
information processing skills, including attention, processing speed and memory, are argued
to be critical to all aspects of cognitive development, with these skills measured in infancy
shown to be predictive of language, working memory and achievement levels in early
adolescence.
Attention
Theoretical models of attention
It is generally agreed that attention is represented by an integrated neural system,
involving contributions from a range of structures, including the brainstem, reticular
activating system and posterior and anterior cerebral regions. Developmental research
demonstrates that the young child has a limited attentional capacity, possibly reflecting the
immaturity of these underlying neural substrates, such as unmyelinated axons and developing
frontal lobes.
Luria proposed two attentional systems operating within the brain. The first he
described as a reflexive or environmentally triggered system that responded primarily to
novel, biologically meaningful stimuli and was characterised by rapid habituation, with
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,higher-order cognition largely unnecessary for its efficient functioning. The second unit,
mediated by more sophisticated cognitive processes and responsible for ‘volitional attention’,
involved a person’s interpretation of environmental stimuli. The more primitive attentional
system was thought to emerge first, soon after birth, with the second, more sophisticated
system developing with increasing experience and maturation. Once the brain matures, the
two systems work in parallel, allowing the individual to monitor the environment while
pursuing various goals guided by intentional behaviour.
Consistent with Luria (1973), Posner suggested two components to attentional
processing. The first is a system predominantly located in the posterior cerebral cortex,
including the parietal lobes, and parts of the thalamus and midbrain, and is primarily directed
towards selective attention and shifts in spatial attention. This system is functional very early
in life (as young as four months of age), as demonstrated by early imaging studies showing
mature metabolism within the parietal lobes around this stage of development. A second,
higher-order system, Posner argued, is primarily subsumed within anterior brain regions
(cingulate gyrus and areas of the prefrontal cortex), but with substantial neural links to
posterior brain regions. This system is associated with enhancing the intensity of the attention
directed towards particular cognitive tasks, with development more protracted, due to the
immaturity of the areas subsuming these skills.
Attention: an integrated functional system
Important skills associated with inhibition are those of self-regulation and monitoring,
the capacity to manage one’s own thoughts, feelings and actions in adaptive and flexible ways
across a variety of contexts. Basic self-regulation skills emerge prior to two years of age and
are thought to be functioning more reliably at around seven years of age, with a further period
of rapid development from eight to ten years of age.
Executive Function
Defining executive functions
Despite the growing literature on executive function (EF), there is little consensus on
its exact definition. EF in adults has been conceptualised as taking a neurobehavioural
‘managerial role’, directing attention,
monitoring activity and coordinating
and integrating information and
activity. Executive skills required to
perform both simple and more
complex tasks are thought to be
essential for efficient day-to-day
functioning. Impairment in these skills
is therefore likely to have serious
implications for a child who is rapidly
acquiring a range of new skills and
abilities.
Executive dysfuntion
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, Executive dysfunction has been consistently reported in children with develop- mental
and acquired conditions. These include children with congenital brain disorders, such as
subcortical band heterotopia, and acquired brain conditions, such as traumatic brain injury,
meningitis, phenylketonuria, and low birth weight.
Socio-emotional skills
The social domain: definitions
The term ‘social skills’ or ‘social competence’ incorporates a range of components.
For the purposes of this discussion, we focus on three specific functional elements: social
competence, social interaction and social adjustment. Social competence is the ability to
achieve personal goals in social inter- action while simultaneously maintaining positive
relationships with others over time and across situations. Social interaction refers to the social
actions and reactions between individuals or groups modified to their interaction partner(s),
while social adjustment represents the capacity of individuals to adapt to the demands of their
social environment.
Chapter 11 | Child Neuropsychology Practice, Assessment
What is child neuropsychological assessment?
Goals and settings
Neuropsychological
assessments have a number of
primary goals: (i) to provide
information regarding the
integrity of the brain via
comprehensive cognitive
assessment; (ii) to detect and
diagnose the presence of
symptoms, syndromes or
disorders; (iii) to characterise
the child’s cognitive strengths
and weaknesses; (iv) to guide
children and their care teams
towards appropriate
rehabilitation, intervention or
support resources based on
ability/disability profiles; and
(v) to monitor outcomes
(recovery or deterioration) and
evaluate the efficacy of treatments and interventions.
Assessment of specific cognitive skills
Attention
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