Cognitive development in children with spastic forms of cerebral
palsy.
Louise Bøttcher, PhD
Boettcher@dpu.dk (corresponding author)
Department of Education, Aarhus University
Tuborgvej 164
2400 Copenhagen NV
Denmark
1
Cognitive development in children with spastic forms of cerebral
palsy.
Louise Bøttcher, Cand Psych, PhD
Abstract
The aim of the paper is to present a theoretical framework that relates the cognitive development of
children with spastic cerebral palsy (CP) to their learning and participation over time. Results from
selected recent studies of the development of general cognitive functioning and specific cognitive
functions in children with CP disagree and highlight a need to address how the initial brain lesions
associated with CP impacts on specific cognitive functions and their interaction over time. Through
the inclusion of the neuroconstructionist paradigm, the initial brain lesion of children with spastic
CP is reconceptualised as a neurobiological constraint on the child’s interactions with its
environment. An early brain lesion, e.g. in the white matter, interferes with normal information
processes that are the foundation of gradual modularisation and affect the brain and the
development of both lower and higher cognitive functions in a wide-spread manner.
Furthermore, even though cognitive development builds on neurological possibilities, the
development of cognition arises from the child’s participation in organised learning activities over
time. It will be argued that in order to understand the cognitive development of children with spastic
CP, we need to include how their learning is supported through their participation in organised
learning activities in school. A model will be proposed that frames how learning activities afford
and develop particular cognitive activities and create developmental possibilities that feedback on
the child’s individual cognitive activity and neural development.
Introduction
2
The aim of this paper is to present a theoretical framework that relates the cognitive development of
children with spastic cerebral palsy (CP) to their learning and participation over time. The paper
will begin with a presentation of three recent studies of general intellectual development (IQ),
followed by a presentation of four studies of the development of specific cognitive functions in
children with (spastic) CP. The aim is to not to give a complete picture of studies of cognitive
development in children with spastic CP, but to point to differences and contrasts within the
material. What becomes apparent is that a developmental approach is necessary. Therefore, the
remaining part of the paper will include concepts from two developmental approaches; the
neuroconstructionist approach and the cultural historical approach in order to create a framework in
which to connect knowledge of neurobiological development with studies of the participation of
children with spastic CP.
Studies of general cognitive functioning.
Studies of general intellectual development (IQ) can only be used to point to overall trends in
cognitive development. Three recent studies have been included (Table 1).
Table 1: Selected recent studies of general intellectual development in children with CP
All three studies follow a longitudinal design, although differences can be found in the follow-up.
The participants are all children with unilateral spastic CP and their cognitive functioning has been
measured with age-appropriate versions of the Wechsler scales. However, the three studies differ in
their results. Muter et al. (1997) found that IQ remained stable. The main objective against the study
is the restricted age range of the children participating in the study and the short follow-up interval.
A significant part of cognitive development takes place after the age of 8 and the study is not
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informative about this. In contrast, Levine et al. (2005) found that IQ declined with age. In their
study, general cognitive functioning was measured at two data-points: one before the age of seven
and one after. The cut-off at the age of seven was chosen because a previous cross-sectional study
had found a decline in IQ beginning around this age. The time between the two data collections
were quite wide-ranging, between 1½ year and 15. Comparing level of performance before and
after the age of seven, a decline in IQ was seen with increasing age, especially for those children
with smaller lesions and higher IQ early on. A decline was seen regardless of seizure status, lesion
laterality and was similar for verbal and performance IQ. The authors suggest that early lesions in
the larger range initially have a greater immediate impact on cognitive functioning whereas the
impact of smaller lesions might not show until later on.
Finally, the third study by Gonzales-Monge et al. (2009) found that the mean (full-scale) IQ was
close to the normal reference score at all three times. No trend was found towards a change of full
IQ with age. However, a decline in PIQ was found.
The three studies of general cognitive functioning illustrate the disagreement about whether IQ is
stable or declines in children with unilateral spastic CP. The difference between Muter et al. (1997)
and Levine et al. (2005) can be explained by the difference in age of the participating children. The
children participating in the study by Muter et al. (1997) might have been too young to show the
decline found by Levine et al. (2005). However, this cannot explain the difference between the two
last studies.
Studies in specific cognitive functions
Studies in general cognitive functioning can only point to general trends in cognitive development.
The general IQ measure may cover up developmental increases or decreases in specific cognitive
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functions that might be more informative about the developmental trajectories of cognitive
development. To examine developmental trajectories of specific cognitive functions, four recent
studies have been selected for further presentation (Table 2). All but one followed a longitudinal
design, mainly with children with bilateral spastic CP, although a couple of studies also included
children with other types of CP.
Table 2: Selected recent studies of the development of specific cognitive functions in children with
(spastic) CP
White & Christ (2005) analysed the development of verbal learning and inhibition using a crosssectional design. Initial learning and retention of information were at the level of the control group
when controlling for general verbal ability. However, learning over repeated trials, strategic
processing (spontaneous use of semantic clustering) and inhibition (interference/intrusion errors of
list B on the retention of list A) were below the performance of the control group. Analysis included
the interaction between age and group and revealed that the difference between the CP group and
the control group was more pronounced in the younger than the older children in the CP group. The
study pointed to a developmental delay. Opposite to what was found in studies of general cognitive
functioning, younger children showed greater impairment compared to same-aged peers and older
children revealed a catch-up.
In contrast, the two papers from Dahlgren Sandberg (2001; 2006), where the second represent a
follow-up of the first one, point to a decline in the development of both literacy skills and working
memory. Even though the children were behind same-aged peers at T1 and T2, they showed
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progress in literacy skills. However, the follow-up study revealed that the progress in the first study
was follow by a developmental arrest between T2 and T3.
The last study in Table 2 by Jenks et al (2009) included a larger group of children, most of whom
had bilateral spastic CP. In this study the development of arithmetic skills was followed through
measurement at five data points. The support of executive functions and working memory on
arithmetic skills was included by the measurement of different aspects of executive functions and
working memory at one data point only, so the study is only informative about the development of
arithmetic skills, not the development of executive functions and memory. Impairment of arithmetic
skills was persistent across all data points and was found to be related to impairments in working
memory and executive functions (updating, visuo-spatial sketchpad, shifting) (Jenk et al. 2009). The
continuance of arithmetic problems might suggest persistent impairments in working memory and
executive functions, at least in the age group in the study.
Taken together, the four studies reveal different developmental trajectories of specific cognitive
functions. In addition, several of the studies suggest that different patterns of interaction between
specific cognitive functions might explain the cognitive developmental trajectories found in
children with spastic CP. Previously, phonological awareness and literacy have been found to be
related and the theoretical assumption has been that phonological awareness supports the
development of literacy. However, this supportive relationship was not found in children with
spastic CP (with accompanying motor speech problems) (Dahlgren Sandberg, 2009). The
hypothesis is that impairments in speech, working memory or the use of strategies for spelling
prevented the children from making use of their phonological abilities the way children usually do
in order to learn how to spell.
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Theoretical approaches to neurocognitive development
Results from different studies paint a complex picture of the cognitive development and call for a
need to address the question; how are we to make sense of the way the initial brain lesions affect the
developmental trajectory of the child with CP, including cognitive development? It is clear that not
one single trajectory exists. We need to include theories of neural development that embrace the
interaction between low level and higher level processes, early and later development and the
environment where the development of cognitive functions take place. As Annette Karmiloff-Smith
has stated: “Development itself is the key to understand developmental disorders” (KarmiloffSmith, 1998). From this neuroconstructive point of view, neural development is conceptualised as a
process of gradual modularisation where neural information processing over time straightens
particular synapses and creates cognitive modules, which is then mirrored in more effective
cognitive functioning. A central biological mechanism is synaptic pruning: the discarding of excess
synapses. At the same time as particular synapses are straightened, excess synapses are discarded
over a prolonged period of time. Both straightening of useful synapses and pruning of excess
synapses builds on cognitive information processes to activate certain synapses and reveal others as
redundant and dispensable (Karmiloff-Smith, 1998). White matter lesions, which are common in
children with spastic CP, give rise to inefficient information processing and impact on the quality of
neural messages between different brain regions (Anderson, 2007). White matter lesions might
interfere with normal processes of brain development because of damage to normal information
processing circuits in the periventricular regions of the brain, whose functionality is of central
importance to the fine-tuning of brain functioning and the development of higher level cognitive
functions. Thus early low level impairments might result in impairments in higher level cognitive
functions later on. It has also been suggested that white matter lesions might alter normal patterns
and timing of myelination (Anderson, 2007).
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Taken together, the understanding of the cognitive development of children with CP needs to
include mechanisms of neural development. A central point of neuroconstructionism is that the
cognitive profile of a child is the systemic result of interaction between different brain regions and
processes and the structuring effect of the environment (Karmiloff-Smith, 1998). The child actively
seeks out stimuli in the environment and through its processing of stimuli sculpts its own neural
system. The initial brain lesion functions as a biological constraint on the child’s interactions with
the environment. This is readily apparent in children with CP, whose motor impairment and often
additional perceptual and cognitive impairments impacts on their possibilities for interaction with
the environment.
Neuroconstructive development as a cultural-historically framed process in specific learning
practices
The systemic interaction between the child and its environment enables the child to change its way
of thinking and acting towards more advanced levels of functioning. This process by which the
child interacts with its environment and changes its cognitive functioning is at the same time a
description of what in the cultural-historical theoretical perspective would be conceptualised as
learning. Both learning and cognitive development denotes processes, where the child changes its
way of thinking and acting towards higher and more advanced ways and do so not only in one
instance, but across situations.
According to this approach, learning is a socially and culturally structured process, where the
instructions, support and other scaffolding processes enable the child to solve cognitive challenges
it would not be able to solve on its own. This is what Vygotsky conceptualised as the zone of
proximal development.
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“The crucial characteristic of instruction is the fact that instruction creates the zone of proximal
development, i.e. elicits in the child, promotes, and brings to movement a number of internal
developmental processes, which at the present time are available for the child only in the sphere of
relations with the people around and in joint action with peers, but which later, undergoing an
internal course of development, become then the internal property of the child himself.” (Vygotsky,
1960, from Valsiner,1997 p. 149).
Vygotsky anchored a child’s zone of proximal development in its current mental development. The
instruction of the adult or the imitation by the child only lead to cognitive development if the child
is able to understand the cognitive exercise it is instructed in or is imitating. From this perspective,
learning is a distributed process by which the child’s cognitive functions are developed through
interactions with others, especially more competent others (Vygotsky, 1998). The important point is
that in order to understand the cognitive development of children with CP, we need to look at both
the individual neurobiological and neuropsychological endowments of the child and how the
learning and cognitive development of that child is supported by his or hers participation in school
and other settings for learning. After all, learning is a cultural and social activity, often situated in
schools, where it is organised by adults according to their goals and aims with the children.
In order to connect the different aspects that are important to understand the cognitive development
of children with spastic CP, the following model is proposed. The model suggests that cognitive
development arises from developmental dynamics that include the children’s’ cerebral lesions, their
individual cognitive functioning and the way their learning activities are organised.
Figure 1: Cognitive development as processes between the brain, cognitive activity and child
participation
9
Knowledge about the child’s brain lesion and its impact on the neural system and neural processes
is indispensable in order to understand its cognitive development. The cognitive functions are
supported by functional neural networks and through feedback processes, the use of neural
networks in cognitive activity develop the neural system to the extent that is possible at the given
time and circumstances. The brain lesion impacts on the left spiral in the model as neurobiological
constraints on the ability of the neural systems and processes to serve the child’s cognitive
processes and, through the feedback process, the possibilities for further development of the neural
systems and processes in the brain.
Child’s participation in settings affording learning and cognitive development covers that the single
child’s cognition takes place within a cultural activity system, e.g. a school, in which the child’s
cognitive processes are supported, transformed, enabled or constrained through the concrete
organisation of learning activities. Different types of learning activities call for different cognitive
activity of the child. Differences in amount of time spent on a subject, e.g. arithmetic, have been
shown to have an impact on the child’s development of arithmetic abilities (Jenks et al. 2007).
The relation between the child’s cognitive functioning and the child’s environment functions with a
spiral-like dynamic, in which the child’s cognition is supported or constrained by the practice
framework of cognition, and the child’s participation in different activities affords and develops
particular cognitive activities and processes and possibly further impact on the development of
neural systems and processes in the left spiral.
In conclusion, what is proposed is that in order to understand the cognitive development of children
with CP, it is necessary to consider how cognitive development arise from the interaction between
two developmental spirals: one between neural structures and processes on the one hand and
10
cognition on the other; and another one between cognition and activities that afford different types
of child (cognitive) activities. Because cognition figures in both spirals, the two developmental
spirals are parts of the same developmental process. And in practice, they work in parallel by
constantly constraining and enabling each other. Together neurobiological, individual and social
processes create developmental possibilities or social constraints that feedback on the child’s
individual cognitive activity and development.
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References
Anderson, V. (2007), “Childhood white matter injuries: What are the issues?” Dev neuropsychol
32(2), 619-623.
Dahlgren Sandberg, A. (2001), “Reading and spelling, phonological awareness, and working
memory in children with severe speech impairment: A longitudinal study”, Augment Altern
Commun 17, 11-26.
Dahlgren Sandberg, A. (2006), “Reading and spelling abilities in children with severe speech
impairments and cerebral palsy at 6, 9, and 12 years of age in relation to cognitive development: A
longitudinal study”, Dev Med Child Neurol 48, 629-634.
Gonzalez-Monge, S., Boudia, B., Ritz, A., Abbas-Chorfa, F., Rabilloud, M., Iwaz, J., Bérand, C.
(2009), ”A 7-year longitudinal follow-up of intellectual development in children with conginital
hemiplegia”, Dev Med Child Neurol 51, 959-967.
Jenks, K. , de Moor, J., van Lieshout, E., Maathuis, K., Keus, I., Gorter, J. (2007), ”The effect of
cerebral palsy on arithmetic accuracy is mediated by working memory, intelligence, early
numeracy, and instruction time”, Dev Neuropsychol 32, 861-879.
Jenks, K., de Moor, J., van Lieshout, E. (2009), “Arithmetic difficulties in children with cerebral
palsy are related to executive function and working memory”, J Child Psychol and Psychiatr 50,
824-833.
Karmiloff-Smith, A. (1998), ”Development itself is the key to understanding developmental
disorders”, Trends Cogn Sci, 2(19), 389-398.
Levine, S., Kraus, R., Alexander, E., Suriyakham, L., Huttenlocher, P. (2005), “IQ decline
following early unilateral brain injury: A longitudinal study”, Brain Cogn 59, 114-123.
Muter, V., Taylor, A., Vargha-Khadem, F. (1997), “A longitudinal study of early intellectual
development in hemiplegic children”, Neuropsychologia 35, 289-298.
12
Valsiner, J. (1997), Culture and the development of children’s action. A theory of human
development, New York, John Wiley & sons.
Vygotsky, L. (1998). The collected works of L.S. Vygotsky. Vol 5. Child Psychology. New York,
Plenum Press.
White, D., Christ, S. (2005), “Executive control of learning and memory in children with bilateral
spastic cerebral palsy”, JINS 11, 920-924.
13
Table 1: Selected recent studies of general intellectual development in children with CP
Paper
Research design
N
Type of CP
Age of children
Findings in regard of developmental
trajectories
Muter et al.,
1997
Longitudinal
38
Unilateral
T1: 3-6
T2: 5-8
IQ remained stable.
Levine et al.,
2005
Longitudinal
15
Unilateral
T1: 4-6
T2: 7-21
Decline in IQ with increasing age.
Gonzalez-Monge
et al., 2009
Longitudinal
32
Unilateral
spastic
T1: 4
T2: 7
T3: 14
FIQ stable, PIQ decline. Neg. effect of
epilepsy and birth prematurity
14
Table 2: Selected recent studies of the development of specific cognitive functions in children with
(spastic) CP
Paper
Cognitive
domain
N
Type of CP
Age of
children
Findings in regard of
developmental trajectories
White &
Christ, 2005
Memory and
executive
function
16
Bilateral
spastic CP
T1: 6-16
(Crosssectional
study)
Dahlgren
Sandberg,
2001
Reading and
spelling,
phonological
awareness,
working
memory
IQ, literacy
skills,
phonological
abilities,
working
memory
7
Dystonia or
spastic CP, all
with severe
speech
impairments
T1: 6
T2: 10
Impairment in verbal learning
and inhibition more pronounced
in younger children, suggesting a
developmental delay in executive
function.
Slower development of reading
and spelling. Auditory memory
behind peers at T1 and T2. Almost
normal developmental trajectory
of phonological awareness.
6
Dystonia or
spastic
diplegia, all
with severe
speech
impairments
T1: 6
T2: 9
T3: 12
Arithmetic
skills,
executive
function,
working
memory
57
Mainly
unilateral or
bilateral
spastic CP (95
%), ataxic CP
(5 %)
T1: 7
T2: 7-8
T3:8
T4:8-9
T5: 9
Dahlgren
Sandberg,
2006
Jenks et al.,
2009
The development seen in
Dahlgren Sandberg (2001) was
followed by an arrest between T2
and T3. Phonological awareness
not predictive of development in
literacy as in normal
development.
Deficits in executive function and
working memory at were related
to arithmetic difficulties that
were persistent over time.
15
Figure 1: Cognitive development as processes between the brain, cognitive activity and child
participation
Developmental time
Develops…
Develops...
…
Neural
systems and
processes
Serves…
Child
cognitions
used in...
Child activity in
settings affording
distributed
cognition
16