The changing panorama of cerebral palsy in Sweden. X. Prevalence and origin in the birth‐year period 1999–2002

Abstract Aim: The aim of the study was to describe the prevalence and origin of cerebral palsy (CP), which is the tenth report from the western Swedish study. Methods: A population‐based study covering 85 737 live births in the area in 1999–2002. Birth characteristics and neuroimaging findings were recorded, prevalence of CP was calculated and aetiology was analysed. Results: CP was found in 186 children. The crude prevalence was 2.18 per 1000 live births. The gestational age‐specific prevalence for <28 gestational weeks was 55.6 per 1000 live births, whereas it was 43.7 for 28–31 weeks, 6.1 for 32–36 weeks and 1.43 per 1000 for >36 weeks. There was a female majority among children born at term and a male predominance in children born preterm. Hemiplegia accounted for 38%, diplegia for 32%, tetraplegia for 7%, whereas 17% had dyskinetic CP and 5% ataxia. Neuroimaging showed white‐matter lesions in 31% and cortical/subcortical lesions in 29%. The aetiology was considered to be prenatal in 36%, peri/neonatal in 42%, whereas it remained unclassified in 21%. Conclusion: The decrease in CP prevalence observed since the 1980s had ceased. An increase in children born at term and in dyskinetic CP was found. In children born before 28 weeks of gestation, the prevalence decreased significantly. White‐matter and cortical/subcortical lesions dominated on neuroimaging.     

Changing panorama of cerebral palsy in Sweden. VIII. Prevalence and origin in the birth year period 1991-94

This 8th Swedish population-based cerebral palsy (CP) report comprises 241 children born 1991-94. The live birth prevalence was 2.12 per 1000. Excluding 7 postnatally-derived cases, the gestational age-specific prevalences were 86 for extremely preterm children, 60 for very preterm and 6 for moderately preterm, and 1.3 for term children per 1000. Spastic hemiplegic, diplegic and tetraplegic subtypes accounted for 33%, 44% and 6%, dyskinetic CP for 12% and simple ataxia for 4%. Neuroimaging had been performed in 90%. Probable aetiology was identified in 73% of preterm and 86% of term children. Among preterm children it was considered prenatal in 12%, peri/neonatal in 61% and unclassifiable in 27%, while it was 51%, 36% and 14% among term children. CONCLUSION: The live birth prevalence for CP in the birth year period 1991-94 continued to decrease slightly. Gestational age-specific prevalences increased marginally in extremely and very preterm births, continued to decrease in moderately preterm births and decreased slightly in term births. Probable aetiology and timing of the brain insult could be revealed in 81%, birth asphyxia being the likely cause in 28% of term children.     

Intrauterine growth in children with cerebral palsy

The risk of cerebral palsy in connection with intrauterine growth retardation has been analysed in a case-control study. The case series comprised 519 children with cerebral palsy born in 1967-1982 in the west health-care region of Sweden and the control series 445 children born during the same years in the same region. The risk of cerebral palsy in small-for-gestational-age infants was significantly increased in term and moderately preterm infants. The highest proportion among infants with cerebral palsy born at term was found in tetraplegia, followed by diplegia and dyskinetic cerebral palsy. It was concluded that small for gestational age on the one hand reflects early prenatal brain damage, and on the other mediates prenatal risk factors compatible with foetal deprivation of supply and also potentiates adverse effects of birth asphyxia and neonatal hypoxia.     

The panorama of cerebral palsy in Sweden part XII shows that patterns changed in the birth years 2007–2010

Aim

This was the 12th population‐based study to explore the epidemiology of cerebral palsy (CP) in western Sweden.

Methods

From 2007 to 2010, there were 104 713 live births in the area. We analysed the birth characteristics, aetiology and neuroimaging findings, calculated the prevalence and compared the results with previous study cohorts.

Results

Cerebral palsy was found in 205 children, corresponding to a crude prevalence of 1.96 per 1000 live births. The gestational age‐specific prevalence for <28 gestational weeks was 59.0 per 1000 live births, 45.7 for 28–31 weeks, 6.0 for 32–36 weeks and 1.2 for >36 weeks. Hemiplegia accounted for 44%, diplegia for 34%, tetraplegia for 5%, dyskinetic CP for 12% and ataxia for 3%. Neuroimaging showed maldevelopment in 12%, white matter lesions in 49%, cortical/subcortical lesions in 15% and basal ganglia lesions in 11%. The aetiology was considered prenatal in 38%, peri/neonatal in 38% and remained unclassified in 24%. CP due to term or near‐term asphyxia had decreased.

Conclusion

A nonsignificant decrease in CP prevalence was seen in term‐born children. Hemiplegia was still the most prevalent CP type, while the prevalence of dyskinetic CP had decreased. One in two children had white matter lesions, indicating late second‐ or early third‐trimester timing.     

The changing panorama of cerebral palsy in Sweden. VI. Prevalence and origin during the birth year period 1983–1986

The prevalence and origin of cerebral palsy in children born between 1983 and 1986 are reported. The crude live-birth prevalence was 2.49 per 1000; 1.56 for term births, 0.93 for preterm births. The increasing trend from 1970 persisted and was statistically significant for both groups. The most pronounced increase during 1983–1986 occurred in term cerebral palsy. The increasing use of neuroimaging techniques made the timing of damaging events more reliable. In term cerebral palsy, the origin was convincingly prenatal in 28% of cases and perinatal in 25%. The particular critical period for the brain damage underlying cerebral palsy was considered to be weeks 26–34 of gestation, i.e. when periventricular structures are extraordinarily vulnerable. In term infants, this occurs during late intrauterine life, while in the majority of preterms it occurs in early neonatal life. In total, two-thirds of cerebral palsy lesions might have been acquired during these decisive months of brain development.     

Bilateral spastic cerebral palsy--prevalence through four decades, motor function and growth.

The aim was to depict changes in the prevalence and severity of bilateral spastic cerebral palsy (CP) over a 40-year period. Another objective was to characterise the group born in 1991-1998 with respect to gross motor function, spasticity and growth. Data were obtained from the CP register of western Sweden and rehabilitation records. RESULTS: After a rise to 1.27 per 1000 live births in 1983-1986, the prevalence decreased significantly, in children born both preterm and at term, to 0.69 in 1995-1998. After 1975, more children were born preterm than at term. There was a significant decrease in severe bilateral spastic CP during the same period, mainly in children born at term. In all, 46% of the children born at term and 33% of those born preterm had a severe motor impairment, i.e. no walking ability. In the 167 children born in 1991-1998, the gross motor function classification system (GMFCS) level was I in 14%, II in 34%, III in 10%, IV in 25% and V in 17%. The GMFCS level correlated with the gross motor function measure (GMFM) and the Ashworth spasticity scores, as well as with the deviation in postnatal weight and height. We conclude that the prevalence of bilateral spastic CP has decreased since the mid-1980s, parallel to a reduction in the severity of the motor impairment. Children born preterm have predominated since the mid-1970s. The severity of the motor impairment correlated with the degree of spasticity, GMFM and growth. The percentage of children who were underweight was substantial.     

脑性瘫痪儿童的MRI特征

目的 探讨脑性瘫痪(脑瘫)患儿脑MR／的表现及其与出生胎龄和脑瘫类型的关系。方法 回顾性分析104例脑瘫患儿的病史、l临床与MR／表现。结果 早产与足月儿脑瘫类型构成显著不同,早产儿以痉挛性双瘫多见(占66．O％),而足月儿偏瘫和失调型高于早产儿。104例脑瘫患儿MR／异常率为84．7％,早产和足月儿组MHI异常率差异无显著性。痉挛型双瘫、四肢瘫、偏瘫、手足徐动型和失调型脑瘫MR／异常率分别为89．4％、100％、100％、54．5％和90．O％。31／42例痉挛性双瘫表现为脑室周围白质软化症(PVL),而以早产儿双瘫更多见(90％);各类型脑瘫的MR／异常表现不同,双瘫以PVL为主,徐动型表现为基底节病变或．PVL失调型绝大部分存在先天性小脑发育不全,偏瘫型突出表现为单侧脑损伤。出生胎龄与MRI特点有关,早产儿组以PVL为特征,见于除失调型外的其他脑瘫类型;足月儿脑瘫MR／异常表现变化多且病变广泛。结论MR／有助于评价各型脑瘫的病理特点及其与出生胎龄的关系．对脑瘫病因的推测有帮助。     

Impact of cerebral palsy in patients discharged from neonatal intensive care units

AIM: The aim of this study was to assess the impact and the peculiarities of cerebral palsy (CP) in children discharged from our neonatal intensive care unit (NICU) from January 1998 to April 2004. METHODS: A total of 2 303 children were discharged from our NICU during this period and 1 912 were followed up for 1 year through neurological examination (traditional, Brazelton, general movements) and cranial ultrasound (US); high-risk newborns were evaluated with brain magnetic resonance imaging (MRI) too. RESULTS: In 65 children (3.4% of the follow-up group) were diagnosed CP, and classified as follows: 21 (32%) diplegia, 19 (29%) quadriplegia, 20 (31%) hemiplegia, 4 (6%) double hemiplegia, 1 (2%) dyskinetic form. In diplegia and quadriplegia prevailed low birth weight infants (less than or equal to 2,500 g) and preterm infants, while in hemiplegia prevailed normal birthweight infants (greater than 2,500 g) and infants at term. The main MRI findings were: in diplegia 82% periventricular white matter lesions; in quadriplegia 94% periventricular and/or subcortical white matter lesions; in hemiplegia 95% bilateral periventricular or subcortical white matter lesions, predominating on contralateral cerebral hemisphere; in double hemiplegia 100% periventricular and/or subcortical white matter lesions, 100% enlargement of subarachnoid spaces; in dyskinetic form 100% basal ganglia lesions. CONCLUSIONS: The impact of CP in children discharged from our NICU, in agreement with the literature, is higher than in the total population of newborns, thus it is very important to evaluate carefully high-risk newborns during hospitalization and follow-up, through neurological examination and radiologic imaging (US, MRI), for an accurate and early treatment.     

Cerebral palsy in Norway: prevalence, subtypes and severity.

BACKGROUND/AIM: To describe prevalence, subtypes and severity of cerebral palsy (CP) in Norway using criteria proposed by the Surveillance of Cerebral Palsy in Europe (SCPE) network. MATERIAL: All children in Norway with CP born in January 1996-December 1998 were registered in the Cerebral Palsy Registry of Norway. The Medical Birth Registry of Norway provided the perinatal data. RESULTS: A total of 374 children with CP were identified with a prevalence of 2.1 per 1000 live births. Detailed information was obtained from 294 (79%) children. Median age at clinical assessment was 6.9 years (range: 1.9-10.2 years). Thirty-three percent of the children had spastic unilateral CP, 49% spastic bilateral, 6% dyskinetic, 5% ataxic CP and 7% were not classified. Severely impaired vision and hearing were present in 5% and 4% of the children, respectively. Active epilepsy was present in 28%, mental retardation in 31% and severely impaired or no speech in 28% children. The most severe impairments in gross motor function were observed in children with low Apgar scores, and the most severe impairments in fine motor function in children born at term, with normal birth weight and low Apgar scores. CONCLUSION: Compared with other populations, the prevalence of CP as well as the proportions of subtypes and gross motor impairments were similar, whereas fine motor impairments and associated impairments were more common. The classification of children with mixed forms of CP is still a challenge. Children were more severely affected if Apgar scores were low, and if they were born at term.     

The changing epidemiology of cerebral palsy.

AIM: To determine the prevalence of cerebral palsy in a specific population. METHODS: Multiple sources of ascertainment were used to create and maintain a register of all cases of cerebral palsy born to mothers resident in the counties of Merseyside and Cheshire in the years 1966 to 1989. Denominator data of infant births and deaths from 1966 to 1981 were obtained from statutory notifications made to health authorities and, for the period 1982-89, from statutory birth and death registrations. Over 1500 cases formed the database for the study. RESULTS: The prevalence of cerebral palsy has increased among all the low birthweight groups with, most recently, an increase in infants weighing < 1000 g at birth. Low birthweight infants now comprise about 50% of all cases of cerebral palsy; in the early years of the study they comprised about 32% of all cases. The proportion of cerebral palsy by clinical type has changed among low birthweight babies, with relatively fewer cases with diplegia and a concomitant increase in the proportion with hemiplegia. An increase in the severity of functional disability, determined by the proportion of children with severe learning, manual, and ambulatory disabilities, was also found. CONCLUSIONS: The change in the epidemiology of cerebral palsy has implications for the aetiology of the condition, and for health, educational, and social service provision.     

The changing panorama of cerebral palsy in Sweden. V. The birth year period 1979-82

The prevalence of cerebral palsy (CP) in Swedish infants born in the four-year period 1979-82 is reported and related to the prevalence in infants born during the twenty-year period 1959-78. In 1979-82 it was 2.17 per 1,000 livebirths, 1.23 for children born at term and 0.94 for preterms, which means that the rising trend since the beginning of the 1970s persisted. The most pronounced rise, from 0.18 per 1,000 livebirths in the period 1967-70 to 0.67 in 1979-82 was found in the subgroup of preterms with spastic/ataxic diplegia. The severity of motor disability and the relative frequency of mental retardation, infantile hydrocephalus and epilepsy among preterm CP children successively increased over the same period of time. The livebirth prevalence of CP in term infants increased slightly but non-significantly during the period 1967-82. The birthweight-specific prevalence of CP per 1,000 newborns surviving the first week of life increased in all birthweight groups during the period 1967-82, significantly for birthweights below 1,500 g and over 2,500 g. The rising prevalence of CP was concomitant with a parallel fall in perinatal mortality, especially in very preterm infants. In the 1980s, severely multi-handicapped, very preterm children, only exceptionally seen among CP children born in the 1960s and 1970s, has become a matter of concern.     

Birthweight specific trends in cerebral palsy.

A register of infants with cerebral palsy born to mothers resident in the Mersey region from 1967-84 has been maintained using various sources of information. A total of 1056 patients are registered of whom 331 (31%) have hemiplegia or mixed hemiplegia, 236 (22%) have diplegias or mixed diplegia, and 369 (35%) have quadriplegia or mixed quadriplegia. The remainder have dyskinetic or dystonic forms except for seven, who are unclassified. There has been no significant change in the prevalence of cerebral palsy among infants of normal birth weight (greater than 2500 g). Among low birthweight infants (less than or equal to 2500 g) there has been a significant increase in prevalence of all the main clinical types. This increase started later among the very low birthweight infants (less than or equal to 1500 g) than among those weighing 1501-2500 g. These changes in prevalence could be the result of either improved survival of prenatally impaired infants because of improvements in medical care, or a reflection of failure to maintain optimal conditions at or around the time of birth.     

Hydrocephalus prevalence and outcome in a population-based cohort of children born in 1989-1998

AIM: To determine the prevalence, aetiology and clinical outcome in children with surgically treated hydrocephalus. METHODS: A population-based study of all 208 liveborn children with hydrocephalus, 124 with infantile hydrocephalus and 84 with hydrocephalus associated with myelomeningocoele, born during 1989-1998 in western Sweden. Aetiological and clinical information was collected from records. RESULTS: The prevalence of hydrocephalus was 0.82 per 1000 live births, 0.49 for children with infantile hydrocephalus and 0.33 for children with myelomeningocoele. The prevalence of infantile hydrocephalus decreased during the period from 0.55 to 0.43 per 1000. In this group, the aetiology was prenatal in 55% and peri-postnatal in 44% of the children. The origin was perinatal haemorrhage in all cases born very preterm. The mortality rate was 5% for children with either infantile hydrocephalus or myelomeningocoele. Mental retardation, cerebral palsy and epilepsy were significantly more frequent in the group with infantile hydrocephalus: 46% vs 16%, 31% vs 4% and 31% vs 10%, respectively. All children with infantile hydrocephalus born very preterm had at least one of these impairments, as did 80% of those with overt hydrocephalus at birth. CONCLUSION: A slightly decreasing trend for infantile hydrocephalus was observed during the 10-y period. Children with infantile hydrocephalus had a worse outcome than those with myelomeningocoele. The need for neurosurgical revisions for two-thirds of the children indicates the need for further development of prevention and treatment strategies.     

Cerebral palsy in southern Sweden I. Prevalence and clinical features

The prevalence, clinical features and gross motor function of children with cerebral palsy in southern Sweden were investigated. The study covered the birth year period 1990-1993, during which 65514 livebirths were recorded in the area. On the census date (1 January 1998), 68366 children born in 1990-1993 lived in the area. The study comprised 167 children, 145 of them born in Sweden and 22 born abroad. The livebirth prevalence was 2.2 per 1000, and the prevalence including children born abroad was 2.4 per 1000. The distribution according to gestational age, birthweight and subdiagnoses was similar to that in earlier Swedish studies, except for a higher rate of dyskinetic syndromes in this study.

Conclusion: The point prevalence of cerebral palsy was 2.4 and the livebirth prevalence was 2.2. Children born abroad had a higher prevalence and were more often severely disabled. Severe disability was often combined with associated impairments such as mental retardation, epilepsy and visual impairment.     

Effects of birth weight,gestational age,and maternal obstetric history on birth prevalence of cerebral palsy.

A register of children with cerebral palsy born to mothers resident in the Mersey region from 1966 to 1977 was compiled from health service records. Frequency distributions and prevalences of birth weight and gestational age differed for those with hemiplegia, diplegia, and quadriplegia. In particular, the children with diplegia showed a bimodal frequency distribution. Children of normal birth weight with diplegia had a higher prevalence of severe mental retardation than those of low birth weight. These differences may be due to survival bias and may not be of aetiological importance. Furthermore, the mothers of diplegic infants had a significantly higher proportion of spontaneous abortions, stillbirths, and low birthweight infants in their obstetric history. This suggests that prenatal factors predominate in the aetiology of diplegia.     

The Changing Panorama of Cerebral Palsy in Sweden

ABSTRACT. The prevalence of cerebral palsy (CP) in Swedish infants born in the four-year period 1979–82 is reported and related to the prevalence in infants bom during the twenty-year period 1959–78. In 1979–82 it was 2.17 per 1000 livebirths, 1.23 for children bom at term and 0.94 for preterms, which means that the rising trend since the beginning of the 1970s persisted. The most pronounced rise, from 0.18 per 1000 livebirths in the period 1967–70 to 0.67 in 1979–82 was found in the subgroup of preterms with spastic/ataxic diplegia. The severity of motor disability and the relative frequency of mental retardation, infantile hydrocephalus and epilepsy among preterm CP children successively increased over the same period of time. The livebirth prevalence of CP in term infants increased slightly but non-significantly during the period 1967–82. The birthweight-specific prevalence of CP per 1000 newborns surviving the first week of life increased in all birthweight groups during the period 1967–82, significantly for birthweights below 1500 g and over 2 500 g. The rising prevalence of CP was concomitant with a parallel fall in perinatal mortality, especially in very preterm infants. In the 1980s, severely multi-handicapped, very preterm children, only exceptionally seen among CP children born in the 1960s and 1970s, has become a matter of concern.     

Infantile hydrocephalus epidemiology: an indicator of enhanced survival.

The epidemiology of infantile hydrocephalus in the birth years 1973-90 was investigated in west Sweden. The study revealed a significant increase in prevalence from 1973-8 and 1979-82 considered due to the enhanced survival of very and extremely preterm infants. The increase did not continue from 1983-90. This could indicate an improved outcome in preterm survivors as the neonatal survival rate continued to increase. The striking predominance of a perinatal/neonatal aetiology in very preterm hydrocephalic infants could be confirmed: 89% born from 1983-90 had suffered a confirmed postpartum intraventricular haemorrhage. In infants born at term, prenatal origins, mainly maldevelopments, dominated. The outcome in very preterm surviving infants with infantile hydrocephalus was poor: 73% had cerebral palsy, 52% epilepsy, 22% severe visual disability, and 55% were mentally retarded. Despite the increased survival resulting in a majority of healthy infants, there is an accumulating cohort of hydrocephalic children.     

The changing panorama of cerebral palsy in Sweden. IV. Epidemiological trends 1959-78

From a population-based series of 773 patients with cerebral palsy (CP) born in 1959-78, an analysis was made of the epidemiological trends over this period of 20 years, divided into five 4-year periods with emphasis on the last two. After a significantly decreasing incidence of CP in the first three periods (1959-70) from 1.9 to 1.4 per thousand, there was a significant increase in the last two periods, reaching 2.0 per thousand in the period 1975-78. Both the decreasing trend in the earlier periods and the increasing trend in the more recent ones were mainly referrable to spastic/ataxic diplegia in preterm CP, and to dyskinetic syndromes in CP infants born at term. With respect to pathogenesis, the corresponding changes in CP incidence were mainly accounted for by the group with potential perinatal risk factors. When analysed on the basis of surviving babies in birth-weight-specific groups, the incidence of CP in 1971-78 was found to have increased in all groups, but this was only statistically significant in the low birth weight group of 2 000-2 500 g. Changing trends in incidences ran parallel with a steadily progressive decline in perinatal mortality through all five periods. A considerable and cumulative net gain of surviving non-CP children was continuously achieved; this was also true for 1970-78, in spite of an increasing CP morbidity during these last two 4-year periods.     

Neurodevelopmental outcome of premature infants born at less than 33 weeks of gestational age and not cerebral palsy at the age of 5 years]

AIM: To appreciate the impact of prematurity, fetal hypotrophy and familial environment on the neurodevelopmental performances of very premature infants without cerebral palsy at the age of five years. POPULATION AND METHODS: We followed a regional cohort of 171 very premature infants (< or = 32 weeks of gestation) until they were five years of age. Cognitive functions were tested with the WPPSI test and the development quotient was assessed by the ability to draw a "bonhomme". Twenty-two premature infants suffered from cerebral palsy diagnosed before the age of two years. Another infant had a moderate diplegia at the five-year examination. We had no information for 16 prematures (9.3% of survivors). Twenty-eight premature infants were considered as having no severe disability on phone or mailed contact, and another child had a severe isolated mental retardation. We examined 104/148 infants, and 96/148 survivors without cerebral palsy passed the tests. The cognitive functions of these premature infants are compared to the performances of a control group made up of 108 children born at term > or = 37 weeks, matched for birthplace and single or twin characteristics of the pregnancy. RESULTS: The values of the different quotients are significantly decreased in the preterm group. The global IQ and the performance IQ are 0.8 SD, verbal IQ is 0.5 SD and the development quotient is 0.4 SD below the values observed in the control group. A performance IQ less than -2 SD for the mean of the control group is observed three times more than in the controls (13.5% vs 3.7%, P < 0.01). Multiple linear regression shows that prematurity explains, independent of hypotrophy and socioeconomic environment, 8% of the variation of the performance IQ (P < 0.01), 2% of the variation of the verbal IQ and 2% of the development quotient (P < 0.05). CONCLUSION: The five-year neurologic outcome of the children born prematurely in this regional study is similar to the results observed in regional studies conducted in Europe: 13.4% of the survivors have cerebral palsy, and the cognitive functions of the children with no cerebral palsy are significantly lower than the term control group. Other risk factors such as hypotrophy, which modulates the developmental quotient, and the socioeconomic status, which modulates the verbal IQ, are underlined.     

Early nasal continuous positive airway pressure in a cohort of the smallest infants in Denmark: neurodevelopmental outcome at five years of age

AIM: To evaluate neurodevelopmental outcome at age 5 y of age in a cohort of preterm children treated mainly with nasal continuous positive airway pressure (CPAP) in the neonatal period. METHODS: A national prospective observational study was conducted in Denmark which included all 269 surviving children with a birthweight below 1000 g or a gestational age below 28 wk born in Denmark in between 1994 and 1995. A total of 164 children (61%) had been treated with nasal CPAP only in the neonatal period. A reference group (n = 76) of term children was studied in parallel. RESULTS: Of the 269 surviving children, 252 (94%) were examined. Twenty-four children (10%) had cerebral palsy, and three children were blind. No case of hearing impairment was detected. Nineteen percent of the index children had an IQ score <-- 2 SD and 42% had an IQ score <-- 1 SD of the mean score of the reference group. CONCLUSIONS: The intellectual development of children in this cohort treated with early nasal CPAP did not suggest a higher proportion of adverse effects on the brain compared to the published follow-up studies of preterm children treated with mechanical ventilation. In our population-based cohort, however, the survival rate for infants below 25 wk of gestation was relatively low and this may indicate a limit for the use of early nasal CPAP.