Marc Wichers

Cerebral Palsy (CP) is defined by the presence of motor impairment resulting from non-progressive cerebral pathology acquired early in life. CP is not a single disease with one known cause and one manifestation, but it is an umbrella term for several distinct cerebral lesions and motor manifestations. It is the largest cause of primary motor disability among children and consequently the children with CP and their parents are a very relevant group in the field of child rehabilitation medicine.

Children with CP and their families often make demands on diagnostic, therapeutic, technical and social facilities. Prevalence estimates (knowing the presence in numbers of these children in relation to the entire population) are needed to improve treatment and services. Information on the distribution of clinical presentations and associated disorders is needed as well. As ‘recent’ Dutch data were not available, the study described in this thesis aimed – among other things – to assess the population prevalence of CP in the Netherlands. This study was performed in a representative Dutch area with 1.2 million inhabitants of whom 172,000 were born between 1977 and 1988. The children were visited and examined, usually at their homes, in the period 1995–1997. The time interval from 1988 guaranteed that the children were at least six years and their motor manifestation of CP had stabilized.

The protocol used in this study was adopted from previous well-known cooperative studies from Germany and Sweden. Criteria for classification were shared and trained with the research workers from these studies. The protocol was expanded with items relevant to the Dutch situation and to Dutch rehabilitation medicine.

Chapter 2 describes the ascertainment and prevalence calculation [1]. Care had to be taken to avoid selection bias. Medical practices (such as rehabilitation centres, paediatric and child neurological departments and institutions for mentally handicapped) were consecutively asked to contact their (supposed) CP cases. Next, the BOSK – association of the physically disabled and their parents – and finally regional media (newspapers, radio stations) assisted in the ascertainment. In total, 170 supposed children with CP – as reported by any of the sources – underwent an examination by an experienced clinician (consultant in child rehabilitation medicine). Of these 170 children, 127 proved to be definite cases of cerebral palsy. This ’loss’ of 25% by early mis-diagnosis was an important finding and it taught us that a too early CP-diagnosis may be challenged. Preferably this must be rechecked at the child’s age of five or six. Under-ascertainment (due to parents’ refusal to cooperate) was present but could be quantified. Looking at major characteristics, the group that refused did not differ significantly from the group that was actually examined.

The population prevalence of CP over the birth year period 1977–1988 was calculated as 1.51 per 1000 inhabitants (average over the 12 birth years). The calculated prevalence however rose significantly over time: from 0.77 (’77–’79) to 2.44 (’86–’88). This rising trend was in accordance with other studies.

Chapter 3 described the distribution of clinical subtypes, motor disability and important co-morbidity (additional signs of cerebral dysfunction such as mental retardation, visual disability and epilepsy) [2]. In-depth studies of medical files in association with the history taken at the visit helped to identify aetiological moments in a majority of cases. Perinatal problems in prematurely born children accounted for fifty percent of identified aetiological moments. By comparing the four most recent birth years with the earlier eight birth years possible trends were studied.

Spastic subtypes accounted for over 90 percent of all CP cases: bilateral spastic cerebral palsy as a group (spasticity on both left and right legs and/or arms) are the majority, although spastic hemiplegia (left or right side affected) is percentage-wise the largest individual clinical subtype. Epilepsy and mental retardation are common. In general the distribution of clinical patterns remained rather constant in following years, as did the other studied items. Comparable studies performed in other countries showed similar findings. Although this study revealed a prevalence rise, no possible explanation for this phenomenon could be found.

Chapter 4 studied the prevalence of impairments of body function and structure (as found at the physical examination) and limitations in functional activities and their inter-relationships in Dutch children with spastic cerebral palsy (CP) [3]. Although their data were present the non-spastic subgroups were too small for valid statistics so they are not included in this chapter. So 119 children with spastic CP, aged 6 to 19 years, were examined. Anthropometry (body measures), gross motor functioning (by Gross Motor Function Classification System, a system to classify gross motor functioning) and manual ability (by Manual Ability Classification System, a similar system), muscle tone, abnormal posture, joint range of motion (ROM) and major orthopaedic impairments were assessed, besides limitations in mobility and self-care activities.

Children with spastic CP on the average had both a lower body height and weight compared to typically developing peers. Over sixty percent walked independently, 40% had no range of motion deficits in the major joints. The rate of impairments was associated with GMFCS and MACS levels. Hip dislocations were rarely encountered and if so only in more severe cases. Children with tetraplegia (legs and arms equally affected) and diplegia (legs more affected than arms) differed in activity limitations. Impairments and limitations in mobility and self-care activities were only modestly related in multivariate analyses. This chapter showed the distribution of CP-related characteristics to be comparable with representative studies of other countries. The distinction between diplegia and tetraplegia is relevant from a functional point of view. The child’s functional limitations are not a straightforward consequence of the neuro-orthopedic impairments, which makes likely that other factors are important as well (such as intra-personal or environmental factors). An activity-oriented approach in rehabilitation medicine goes beyond treating specific impairments.

Chapter 5 explored characteristics of personality descriptors, communication and behaviour difficulties in the representative group of children with cerebral palsy. Personality descriptors (addressing self-esteem, control, prosocial capacity and mood), difficulties in communication, contactual skills and problem behaviour were assessed at the interview with the parents. We found that the felt degree to have control over one’s life and self-esteem appeared to be restricted in 10–20% of the children. Mood was not a specific problem in children with cerebral palsy. The ability to express oneself was impaired in 26%; writing was impaired in 50%. Approximately one third suffered from incidental to frequent behaviour problems. Impaired intellectual functioning was an associated factor with behaviour problems, impaired gross motor functioning to a lesser extent. This chapter concludes that the most prevalent psychological and socio-emotional problems in children with CP appeared to be emotional instability, being dependent, lack of confidence and communication limitations (self expression and writing). Children without intellectual disability seem to function without significant problems. For daily practice: it is important for professionals to be attentive not only to academic achievement but also to emotional and behaviour problems, in order to stimulate the children’s development towards participation and autonomy.

Chapter 6 describes health care utilisation – in the broad sense – and school careers of Dutch children with cerebral palsy. The interview with the parents focused on the child’s previous and current situation in medical and allied health care and school career. It was found that eighty percent of the Dutch children with CP are seen on a regular basis by a consultant in rehabilitation medicine. Hip and ankle-foot surgery has respectively been performed in 24 and 20 percent of children, hip surgery mainly in strongly affected children (GMFCS level IV or V). Apart from anti-epileptic medication and laxatives (in 20% and 5% respectively) hardly any medication is taken, notably no spasmolytic drugs. Orthotic devices (orthopedic shoes or orthoses) are used by 80% of the children, mobility devices (wheelchairs, special bicycles) by 50%.

Sixty-two percent of the children are treated in a multidisciplinary setting and 56% attend special schools, multidisciplinary treatment and school frequently in combination. Less affected children (with GMFCS level 1 and normal intelligence) more often had monodisciplinary or no treatment at all and attended mainstream schools.

In conclusion: Dutch practice regarding CP children, especially for those more affected, features special schools combined with multidisciplinary treatment. Adaptive devices and orthopaedic surgery are widely used. Medication use is minimal. Timely preventive hip surgery probably contributes to the low rate of hip dislocation in the Netherlands.

Chapter 7, the General discussion starts with a recapitulation of the reason and scope of the study. The separate chapters are summarized and, if applicable and not discussed in the chapter itself, considerations or knowledge known from more recent practice or studies performed abroad are discussed. After all, even though this study’s field work is from some time ago, no more recent Dutch data is available at a population-based level.

More recent prevalence rates as known from studies abroad do not seem to indicate that the strong rise as reported by us in the birth years up to 1988 has continued. Most likely prevalence across Europe stays between 2 and 3 per 1000. If the last Dutch prevalence calculation (2.44 per 1000, calculated for the birth years ’86–’88) were still valid in recent years, in the Netherlands in each year group we would see some 400 children with CP.

The General discussion ends with three recommendations. First: check the working diagnosis CP in a young child by looking again to the clinical manifestation at age five or six – as advocated by SCPE.

The second recommendation is that, as CP is not a life-threatening condition, care and services should focus not only on children. The transition of youth to adulthood needs major attention and so do adults with CP. The Dutch system, as described in chapter 6, often provides for children a daily environment of multidisciplinary rehabilitation and school together. After leaving school, the young man or woman with CP (and family or partner) finds the medical, technical and social services no longer at one place. The needs also change with growing into or in adulthood.

The third recommendation in the general discussion is: start a Dutch CP register or at least find out if a Dutch CP register is feasible. In other countries, professionals and policymakers are informed on regional rising or falling rates of CP, possible changes in distribution of the CP picture itself or of important associated disorders. Representative and reliable information is gathered there via regional CP registers that work at the standards set by and cooperate within, the Surveillance of Cerebral Palsy in Europe group. As such they contribute to multi-centre research, an important example of which is SPARCLE, a European multi-centre project focusing on contextual factors and quality of life.

The Netherlands are outsiders again in this field - after this survey on birth years 1977 through 1988. There is little sense in performing a one-time survey again. A Dutch register should focus on an area of some 1.5 million inhabitants and be set up for no less than twelve or fifteen years in order to truly signal trends. Policymakers have to be informed to cooperate and provide funding. Essential support is needed from the professionals ‘in the field’, that report on children with CP in the register’s area, of course with privacy. Then the register itself needs careful management of people, data and resources.

Then again, a register set up for children with CP could provide information as well on children with other conditions that cause activity limitations (e.g. neuromuscular diseases, rheumatoid diseases). This would change the register’s scope from disease-oriented to activity-oriented as well and this would increase its benefits to society. A register is something that has to be set up well – there is no way of doing it “half”.