Developmental neuropsychology
Lecture 1: Course introduction, principles of child neuropsychological
assessment
Chapter 1: Child neuropsychology
- Historical models
- Current models
- Biopsychosocial model
- Case of Hannah
Learning goals:
- Know foundations of child neuropsychology and the two seminal models (by Rourke and
Dennis)
- Understand the current multidimensional models of child neuropsychology
- Explain the biopsychosocial view of child neuropsychology
Child neuropsychology/ Study of brain-behavior relationships within the context of an
pediatric immature but rapidly developing brain and the implementation of the
neuropsychology knowledge gained into clinical practice. Informs us our understanding
of typical child development by providing a framework within which
to explore and map parallels between brain maturation and cognitive
and socio-emotional development.
Improvements in skills are closely associated with increases in myelination during infancy and
childhood. Adolescent risk-taking behaviors are associated to critical periods in frontal lobe
development and connectivity.
Kennard Principle Relatively good recovery following early brain insult. The theory of
recovery of function states that young children’s brains are less
differentiated than that of an adult and are therefore more capable of
transferring functions from damaged cerebral tissue to healthy tissue.
Critical period The time window during which external influences have a significant
effect. Early brain insult will have different consequences at different
times throughout development and can be more detrimental than
later injuries in some cases because some aspects of cognitive
development are critically dependent on the integrity of particular
cerebral structures at certain stages of development.
Non-verbal learning disability (NVLD) by Rourke= generalized cerebral dysfunction resulting from
brain insult occurring during the perinatal period or in infancy. Characteristics are:
- Bilateral tactile-perceptual deficits, more marked on the left side of the body
- Impaired visual recognition and discrimination and visuospatial organizational deficient
- Bilateral psychomotor coordination problems, more marked on the left side of the body
- Difficulties managing novel information
Intact skills include;
- Simple motor skills
- Auditory perception
- Rote learning
- Selective and sustained attention for auditory-verbal information
, - Basic expressive and receptive language
- Word reading and spelling
The greatest contribution of the NVLD model is linking cognitive characteristics to underlying
neurologic explanations white matter hypothesis= normal development of white matter is
essential for intact child development. NVLD occurs when there is disruption to white matter
development during critical stages of early childhood.
Three principle axes of relevance in brain-behavior relationships: left-right, up-down, anterior-
posterior.
Dennis: focuses primary on age/developmental stage at time of insult and progression in cognitive
skills with time since insult. The heuristic describes the impact of brain damage on language
development. Skill development in several levels:
- Emerging; ability is in the early stages of acquisition, but not yet functional
- Developing; a capacity is partially acquired but not fully functional
- Established; abilities are fully matured
There are three crucial age related variables;
1. Age at time of lesion= determines the nature of the cognitive dysfunction.
2. Age at testing= healthy children also vary in their ability to perform cognitive tasks at
different developmental stages.
3. Time since insult= differing performance patterns identified at different stages of recovery,
with increases in some cognitive skills, but failure to develop others.
Cognitive reserve model= individual differences in a
child’s reserve capacity, both brain reserve capacity
(BRC) and cognitive reserve capacity (CRC).
- BRC= measured by quantifying variables (insult
severity, brain volume or structural
connectivity). When BRC is below threshold
levels, functional deficits emerge.
- CRC= factors both intrinsic (pre-injury cognition,
behavior and post-injury cognition) and extrinsic
to the child (socio-economic status, family
functioning), which impede/facilitate various
functional outcomes.
Lesion location and functional network involvement
have been shown to be important for determining functional outcome in a range of brain conditions,
with varying degrees of functional plasticity and outcome associated with involvement of different
brain structures and networks.
Recovery continuum model= potential risk and resilience factors
interact to determine long-term outcomes. It incorporates
factors that are established as important for outcome post-child
insult, including;
- Nature (global, diffuse) and severity (mild/severe,
presence of complications) of insult
, - Developmental stage of child (infant, child, adolescent) and timing of assessment
- Pre-injury child characteristics
- Environmental context (distal and proximal factors) and access to interventions and social
supports
Dimensions of child neuropsychology;
- Brain; bio dimension
In the prenatal period, interruptions to brain
development result primarily in structural
abnormalities (dysplasia, neural tube defects,
agenesis of the corpus callosum).
Postnatal development is largely directed towards
elaboration of the brain, establishing the
connectivity vital for the system to function
effectively (dendritisation, synaptogenesis,
myelination).
Early disruption to central nervous system (CNS)
development may have irreversible consequences.
Children with early insults may grow into their difficulties as demands increase through
late childhood into adolescence.
EEGs are used to diagnose epileptic disorders and sleep disturbance
ERPs focus on dysfunction within sensory or information processing systems
- Environment; the social dimension
A child exists within a tight social system (family) with that system responsible for the
quality of the environment, access to resources and provision of an appropriate context
for learning.
Studies demonstrated reduced brain volume, impacting both grey and white matter as
well as deficits in structural connectivity and atypical brain activation in survivors of early
trauma.
Studies shown that children from previously dysfunctional/low SES families have more
problems. Where parents are depressed/distressed, the cognitive and social
development of the child are reported to be poorer double-hazard hypothesis= brain
insults may have greater consequences in children from socially disadvantaged
backgrounds.
- Socio-emotional function; the psych dimension
Piaget:
1. First stage (from birth to two years); primarily simple motor and sensory activities
emerge gradually, development of object permanence and joint attention.
2. second stage (around 2 years old); development of symbolic and early language,
communication and mental imagery with rudimentary theory of mind and empathy
becoming apparent later during this stage.
3. Operational (age 7); increased reasoning and problem-solving ability, capacity to
integrate information across multiple dimensions and to perform mental
transformations. As well cold (reasoning, problem-solving, organization and mental
flexibility) as hot (social cognition) abilities in executive skills are developed.
As a child grows and less support is available, child behaviors and social interactions may become
more problematic, and therefore resulting in mental healthy problems and social withdrawal.
, Case of Hannah: when she was four years old, she got hit by a car while playing outside with her
older brother. She was followed over a ten-year period. Before the accident there were no significant
family, social or marital difficulties. At the scene of the accident she was unconscious and taken to
the hospital by ambulance.
- Early recovery; diagnosed as suffering from severe traumatic brain injury. At 20 days post-
injury significant speech, mobility and coordination impairments and was transferred to
the rehabilitation service for intensive physical, occupational and speech therapy. She was
discharged at 6 weeks post-injury. She had limited functional communication and severe
attentional problems, severe truncal ataxia and motor incoordination.
- Social dimension; mother remained at the hospital. Her younger sister went to their
grandparents. Dad and her older brother stayed home. Family disruption and fragmentation
is not uncommon following an acute illness and can result in an inability of the family to
communicate adequately at times of severe stress and to support each other and deal with
acute responses to trauma.
- Psych dimension; by age 16 her results on neuropsychological test measures were at the level
expected for a 7-year old child. Her poor progress is consistent with her school history and
reflects her inability to cope in the face of increasingly complex life demands. She was able to
manage basic daily living skills (bathing, washing, dressing, feeding) but unable to perform
more complex activities (cooking, shopping). Her family had become socially isolated,
maintaining a few old friends but little motivation or capacity to establish new networks. At
the outset, Hannah may have been predicted to have good prognosis, despite the severity of
her injury. Her injury was at a young age, suggesting the possibility of functional brain
reorganization.
Chapter 3: Cognitive and social development
- Milestones in motor, visual and communicational/social development till 5+ years
- Models and development of: attention, memory, speed of processing, executive function,
socio-emotional skills
Learning goals:
- Understand that there is large variability to reaching developmental stages in childhood,
which is increased with brain pathology
- Explain the difference between domain-specific and domain-general models of cognitive
development
- Identify the common domains of childhood neuropsychological assessment: attention,
memory, speed of processing, executive function, socio-emotional skills
- Recognize theoretical models supporting these neuropsychological domains
- Know the general developmental course of these neuropsychological domains
Domain-specific approach Based on modular/localizationist approach. Individual cognitive skills
are seen as developing according to a unique time-table and set of
rules.
Domain-general view The emergence of cognitive skills follow 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.
