Cerebral Palsy. Clinical Trial
Official title:
Exploring Hypertonia in Children With Cerebral Palsy- a Population-based Approach.
Abnormal limb and trunk movements are seen in many children with cerebral palsy. Recognizing the difference between types of these movements is not well understood. This study aims to describe how common are these movements in children recruited from a population-based sample of children identified on a cerebral palsy register, and to explore associations with motor abilities. It is hoped this will lead to improved understanding and recognition of movement disorders in CP, to allow clinicians to choose appropriate treatments. We hypothesise that the underlying prevalence of dyskinesia is higher than that previously identified through conventional motor descriptions in cerebral palsy populations in Australia, and may approach 20%.
A key descriptor associated with the term cerebral palsy is "the disordered development of
movement and posture, resulting in activity limitation." The term "movement disorders" is
now commonly used to describe a range of observed abnormal movements and postures displayed
by children with chronic neurological conditions, of which cerebral palsy (CP) is the most
common. These children have muscle tone abnormalities related to non-progressive damage to
motor pathways, in particular those contained within the cortex, basal ganglia and thalamus.
In recent years there has been much focus on understanding and treating abnormal tone and
movements in children with CP, including spasticity and dystonia. Spasticity, which occurs
in approximately 90% of children with CP is defined as the velocity-dependent resistance of
a muscle to stretch. In general, spasticity is elicited during a standard clinical
examination, such as by passive range of joint motion performed at varying speeds.
Dystonia in childhood is defined as ''a movement disorder in which involuntary sustained or
intermittent muscle contractions cause twisting and repetitive movements, abnormal postures,
or both. ''. In contrast to spasticity, dystonia is inherently more difficult to observe and
measure, particularly when spasticity co-exists. When classified according to the dominant
form of tone abnormality, it accounts for up to 2-15% of cases. However it is often
overlooked in the diagnostic formulation of motor aspects of cerebral palsy, and therefore
does not necessarily figure in treatment decision-making. Under-recognised dystonia, when
co-existent with spasticity, can produce unpredictable surgical outcomes in the management
of gait disorders and associated musculoskeletal deformities. In addition, other abnormal
movements such as chorea and athetosis may be observed in these children, adding to the
complexity of the movement disorder, but are rarely classified as dominant abnormalities.
Improving the recognition of dyskinesias, and situations where they co-exist with
spasticity, is important not only for promoting a clearer description of tone and movement
abnormalities, but also to help tailor appropriate treatments leading to improved outcomes.
In our recent study describing the motor profiles of 247 5-year-old children in the South
Australian CP population, 93.2% of children were coded as primarily spastic-type; 3.2% as
dyskinetic (dystonia or athetosis) and 3.6% as ataxic.1 However this study also found that
when children were assessed face-to-face by a group of expert paediatricians, 19.4% of the
population was noted on observation alone to have abnormal movements, which included
dyskinesias. This increased with motor severity by Gross Motor Functional Classification
System (GMFCS) from 7% (level I) to 45% (level V). We questioned whether in fact recognition
of some dyskinesias are "masked" by the presence of spasticity, according to conventional
clinical descriptors. We advocated for the development of a classification system that
describes spasticity and dystonia in parallel, to aid the clinician in prescribing treatment
strategies. To date no published study has systematically examined for the prevalence of
abnormal movements in CP populations, beyond determining the dominant form of tone
abnormality in a mutually exclusive fashion, e.g. spasticity or dystonia. Our study proposes
a mutually inclusive format using a recently validated tool for the recognition of dystonia
and other abnormal movements.
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Observational Model: Cohort, Time Perspective: Cross-Sectional