Selected risk factors for spastic cerebral palsy in a retrospective hospital-based case control study.
Cerebral palsy (CP) is one of the most common causes of physical disability in children. The prevalence of CP in the general population is 1.5 to 2.5 per 1,000 live births [1, 2]. The prevalence of CP in the Polish population is estimated at 2 to 3 per 1,000 live births . In Poland, during their first year approximately 1,200 to 1,300 children are diagnosed with CP based on observed symptoms. Despite the development of monitoring technology and life-saving interventions for newborns, including those with low birth weight, the prevalence of CP has remained largely unchanged for the past 30 years. In preterm infants, an increasing prevalence of CP has been documented and is believed to be related to the improvement in survival rates .
CP is not an independent disease, but a syndrome associated with various etiologies affecting the central nervous system. CP describes a group of disorders of the development of movement and posture, causing activity limitations that are attributed to non-progressive disturbances that occur in the developing fetal or infant brain . The motor disorders of CP are often accompanied by disturbances of sensation, cognition, communication, perception, behaviour, and/or by a seizure disorder. CP is associated with prenatal, perinatal, and neonatal risk factors. Premature birth is recognized as the main risk factor for CP, while perinatal asphyxia accounts for less than 10 to 20 percent of cases [6-10].
A number of pre-pregnancy risk factors have been described including maternal age, parity and maternal diseases including epilepsy, diabetes, and thyroid disease [11,12].
Risk factors occurring early or late in pregnancy are assisted fertilization, male gender, congenital malformation, multiple pregnancy and intrauterine growth restriction [13,14].
CP describes a group of disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain . The motor disorders of CP are often accompanied by disturbances of sensation, cognition, communication, perception, and/or behaviour, and/or by a seizure disorder.
Increasingly, more very low birth-weight infants in the developed world are now expected to survive the neonatal period than was previously the case. According to the UK Network of Cerebral Palsy Registers, Surveys, and Databases, low birth-weight infants are at greater risk of developing CP than higher birth-weight babies . The CP rate amongst children with birth weights <2500 g was significantly higher at 16 per 1,000 live births than 1.2 per 1,000 live births for normal birth-weight children. Despite being at greater risk of developing CP, smaller birth-weight babies are proportionately less likely to develop the most severe forms of motor impairment. Furthermore, CP rates for each motor impairment group in the 1990s were similar to those in the late 1970s. The CP rate for infants weighing 1,000 to 1,499 g at birth decreased from around 180 per 1,000 live births in 1979 to around 50 per 1,000 live births from the early 1990s onwards.
Brooks et al.  assessed the trend of improved survival among individuals with (CP) in California during the 1980s and 1990s. In an observational cohort study, they evaluated individuals with CP ages 4 years and older who were clients of the California Department of Developmental Services. A total of 51,923 persons with CP were studied. Medical diagnoses, functional disabilities, and special healthcare requirements were assessed with the Client Development Evaluation. Children who did not lift their heads in the prone position who were born in more-recent years had significantly lower mortality rates than those with comparable disabilities born earlier. The authors concluded that the trend toward improved survival has continued throughout the most-recent decade.
Recently, most studies of CP have been carried out in Western countries, with very few having been conducted in the Eastern European countries. There are also few reports on risk factors for CP from our country . Thus, we attempted to identify risk factors associated with CP in our retrospective study in Bialystok. A better understanding of the aetiology of CP is necessary for the development of preventive strategies and treatments. The aim of this study was to investigate the selected risk factors for CP using a hospital-based case control study.
MATERIALS AND METHODS
We evaluated 1200 medical data of the patients who were under the care of the Department of Pediatric Rehabilitation of the Medical University of Bialystok. The study was approved by the Ethics Committee at the Medical University of Bialystok, Poland. We included in the retrospective analysis 92 children with spastic CP. The control group comprised 96 healthy children. A total of 96 children without CP were included in the study. Controls were selected from the entire geographical population. Children were of similar age. The mean age of patients with CP was 10.9 [+ or -] 6.9 years with a range of 1-17 years of age. The mean age of healthy children was 12.4 [+ or -] 4.3 years with a range of 4-16 years of age and did not differ significantly. Gender, Apgar score, number of pregnancies and deliveries, cesarean sections, birth weight, preterm and term deliveries and epilepsy were analyzed We also analyzed the type of CP , the motor and mental development of children with CP and the control group.
Each child was classified according to the Gross Motor Function Classification System (GMFCS): level 1, walks without restrictions; level 2, walks without assistive devices, limitations in walking outdoor; level 3, walks with assistive devices; level 4, self-mobility with limitations, children are transported or use powered mobility; and level 5, self-mobility is severely limited.
The differences between the groups were determined by the parametric t-test and nonparametric statistical tests: Fisher's Exact test or chi-square test where appropriate. All P values were two-tailed. Statistical significance was defined as P < 0.05. To test the effects of the sex, birth weight, type of CP, mental retardation Spearman rang regression was applied.
A total of 92 patients with CP, 64 boys (69.6%) and 28 girls (30.4%), were recruited. In this group, the number of boys was significantly higher (p=0.003) than the number of girls. The control group included 53 girls (55.2%) and 43 boys (44.8%). The mean age of children with CP and controls was similar. The study population comprised 27 children with congenital hemiplegia (2.36%), 35 with spastic diplegia (38.04%), and 30 with spastic tetraplegia (32.6%). The mean gestational age at birth for children with CP was 35.96 [+ or -] 4.2 weeks versus a mean of 39.2 [+ or -] 1.4, (p<0.001) for the control group. The mean number of pregnancies and deliveries for mothers of children with CP compared to the control group did not differ significantly. Details are shown in Table 1.
Vaginal births and cesarean sections in the children with CP and controls occurred in similar percentages (p=0.568). The birth weight of children with CP (2615.8 [+ or -] 935.1) was significantly lower than birth weight among the control group (3343.2 [+ or -] 497) (p=0.04). Almost 40 percent of the children with CP were born to mothers who had preterm labour, compared to only 5.2 percent of the children without CP (p<0.001). A mean Apgar score for children with CP (5.9 [+ or -] 3.3) at 1 minute was significantly lower than for children without CP (9.10 [+ or -] 1.5) (p<0.001). Of the children with CP, 27 (20.1%) had epilepsy; none of the children without CP had epilepsy. Almost 52 percent of patients with spastic tetraplegia, 22 percent with spastic diplegia, and 15.5 percent with spastic hemiplegia had epilepsy. Of children with CP, 45 (48.9%) had normal mental development and all children (100%) of the control group had normal development. In regard to delayed development, 20 patients with CP (21.7%) had small delays, 16 (17.4%) had moderate delays, and 11(12%) had severe delays. The children with CP were more frequently classified into levels II (n=25) and V (n=20) of the GMFCS; other patients were classified into levels I (n=18), III (n=14), and IV (n=15).
Of children with CP, 12 (13%) were unable to sit independently. The mean age for sitting independently was 1.1 [+ or -] 0.8 years and was significantly delayed compared to the control group. Details are shown in Table 2.
Of children with CP, 19 (20.1%) were unable to stand independently. The average age for standing independently in children with CP was 1.2 [+ or -] 0.99 years and differed significantly (p=0.0045) compared to controls. Of children with CP, 20 (21.7%) were unable to walk independently. The mean age for walking independently in children with CP was 1.5 [+ or -] 0.7 years and differed significantly (p<0.001) compared to the control group. Of children with CP, 18 (19.6%) were unable to speak. The average age for speaking in children with CP was 1.4 [+ or -] 0.98 years and differed significantly compared to the control group (p=0.003).
Gender, number of pregnancies and deliveries, birth weight, and preterm versus term deliveries were not related to psychomotor development in children with CP. (Details are shown in Table 3). Birth by cesarean section, Apgar score at 1 minute, epilepsy, and mental retardation were related to psychomotor development in children with CP.
In the present study, we demonstrated that maleness, perinatal asphyxia, low birthweight, premature birth, and epilepsy were independent factors correlated with CP. The psychomotor development of children with CP was also correlated with these factors.
This study's result that the risk of CP is significantly greater in males than in females agrees with earlier findings [17-19]. Males born preterm also appear to be more vulnerable to white matter injury and intraventricular hemorrhage than females. Experimental studies of adult animals and data from adult patients who have experienced a stroke indicate that sex hormones such as estrogens protect against hypoxic-ischemic injury and influence the neonatal brain.
Skiold et al.  demonstrated that cognitive and language outcomes in infants aged 30 months were poorer in males born preterm. Sex-related differences were also observed on neonatal structural MRI, including in the patterns of correlations between brain volumes and developmental scores at both global and regional levels.
The pathogenesis of CP is multifactorial. Factors contributing to fetal brain injury may be acute (i.e., within hours) or chronic (i.e., over days or weeks), as well as either continuous or intermittent . Epidemiological studies [20-22] have confirmed that the incidence of CP is inversely related to gestational age. Meanwhile, EpiCURE determined the survival and neonatal morbidity rates for infants born between 22 and 26 weeks of gestation in the U.K. during 2006 and, compared to results from 1995, showed changes in outcome for infants born between 22 and 25 weeks . In 2006, CP was present in 14% of survivors. Though the survival of infants born between 22 and 25 weeks of gestation had increased since 1995, the pattern of major neonatal morbidity and proportion of survivors affected remained unchanged. Furthermore, the results of the present study corroborate these earlier findings, all of which indicate a substantial increase in the population of preterm survivors at risk of later health problems.
Asphyxia at birth remains the primary cause of CP [23-24] and, accordingly, the current study showed that asphyxia was significantly correlated with CP. However, wide disparity persists in estimating the proportion of CP attributable to asphyxia at birth. According to Ellenberg and Nelson , available data do not support the belief, widely held in the medical and legal communities, that asphyxia at birth can be recognized reliably and specifically, or that CP is often due to asphyxia at birth.
Previous studies have demonstrated infants with low birthweight are at greater risk of developing CP than those with higher birthweight [26-28]. The rate of CP among children with birthweights of less than 2,500 g was significantly higher (16 per 1,000 live births) than among infants born with normal weight (1.2 per 1,000 live births) . In the present study, low birthweight was also significantly associated with the development of CP.
In a study of premature infants, Rutkowska et al.  evaluated the development of infants from birth until the age of 2 years. Of the 162 children who participated in the examination at the age of 2 years, normal development was observed among 88%, and CP of different types was diagnosed in 8%. Hustad et al.  examined early speech and language development in children with CP and found that 85% of 2-year-old children with CP in their study had clinical speech and/or language delays relative to expectations for their age. They suggested that children with CP receive speech and language assessment and treatment at or before 2 years of age. These findings are consistent with our results, which show that, of all children with CP, 19.6% were unable to speak. The average age for speaking in children with CP was 1.4 [+ or -] 0.98 years, which differed significantly to that of the control group.
The frequent association of epilepsy and CP is of special interest. It has been estimated that 15-90% of patients with CP suffer from epilepsy [30-31], which our results corroborate. Zafeiriou et al.  reported that the overall prevalence of epilepsy in children with CP was 36.1%. Patients with atonic-diplegic, dystonic, tetraplegic, and hemiplegic CP had a higher incidence of epilepsy. In all, 75.3% of patients has been seizure-free for more than 3 years and could discontinue therapy, whereas 25% of patients were still taking antiepileptic drugs. Among a cohort of 452 patients with CP, Singhi et al.'s  retrospective study found a 35% rate of epilepsy, which most commonly affected children with spastic hemiplegia and tetraplegia.
Several studies have identified significant relationships among mental retardation, motor impairment, and epilepsy [32,33]. Vargha-Khadem et al.  reported that the presence of epilepsy n patients with hemiplegia was clearly associated with more severe cognitive difficulties. Furthermore, Bruck et al.  found a higher rate of severe mental retardation in patients with spastic tetraplegia and who had epilepsy. In the present study, nearly 52% of patients with spastic tetraplegia, 22% with spastic diplegia, and 15.5% with spastic hemiplegia also had epilepsy, and nearly half of our patients with CP and epilepsy had severe mental retardation. There is also an association between epilepsy in children with CP and the degree of mental impairment. The occurrence of epilepsy, mostly in children with hemiplegia and diplegia, is associated with reduced mental capacities .
Gender, prematurity, low birthweight, asphyxia, and epilepsy were related to the development of CP. The psychomotor development of children with CP significantly differed from that of the control group. Of patients with CP, nearly 20% had epilepsy, while 50% had mental retardation.
Conflicts of interest
There are no conflicts of interest.
[1.] Vincer MJ, Allen AC, Allen VM, Baskett TF, O'Connell CM. Trends in the prevalence of cerebral palsy among very preterm infants (<31 weeks' gestational age). Paediatr Child Health. 2014 Apr; 19(4):185-9.
[2.] Oskoui M, Coutinho F, Dykeman J, Jette N, Pringsheim T. An update on the prevalence of cerebral palsy: a systematic review and meta-analysis. Dev Med Child Neurol. 2013 Jun; 55(6):509-19.
[3.] Mieszczanek T.: Selected epidemiologic aspects of cerebral palsy in the population of children and adolescents in west-east Poland. Neurol Dziec. 2003; 12:13-21. (Polish)
[4.] Vincer MJ, Allen AC, Joseph KS, Stinson DA, Scott H, Wood E. Increasing prevalence of cerebral palsy among very preterm infants: a population-based study. Pediatrics. 2006 Dec; 118(6):e1621-6.
[5.] Bax M, Goldstein M, Rosenbaum P, Leviton A, Paneth N, Dan B, Jacobsson B, Damiano D; Executive Committee for the Definition of Cerebral Palsy. Proposed definition and classification of cerebral palsy, April 2005. Dev Med Child Neurol. 2005 Aug; 47(8):571-6.
[6.] Pritchard MA, Colditz PB, Cartwright D, Gray PH, Tudehope D, Beller E. Risk determinants in early intervention use during the first postnatal year in children born very preterm. BMC Pediatr. 2013 Dec 5; 13:201.
[7.] O'Callaghan M, MacLennan A. Cesarean delivery and cerebral palsy: a systematic review and meta-analysis. Obstet Gynecol. 2013 Dec; 122(6):1169-75.
[8.] Stoknes M, Andersen GL, Elkamil AI, Irgens LM, Skranes J, Salvesen KA, Vik T. The effects of multiple pre- and perinatal risk factors on the occurrence of cerebral palsy. A Norwegian register based study. Eur J Paediatr Neurol. 2012 Jan; 16(1):56-63.
[9.] Tronnes H, Wilcox AJ, Lie RT, Markestad T, Moster D. Risk of cerebral palsy in relation to pregnancy disorders and preterm birth: a national cohort study. Dev Med Child Neurol. 2014 Aug; 56(8):779-85.
[10.] Kulak W, Okurowska-Zawada B, Sienkiewicz D, Paszko-Patej G, Krajewska-Kulak E. Risk factors for cerebral palsy in term birth infants. Adv Med Sci. 2010; 55(2):216-21.
[11.] Blair E, Stanley F. When can cerebral palsy be prevented? The generation of causal hypotheses by multivariate analysis of a case-control study. Paediatr Perinat Epidemiol. 1993 Jul; 7 (3):272301.
[12.] Thorngren-Jerneck K, Herbst A. Perinatal factors associated with cerebral palsy in children born in Sweden. Obstet Gynecol. 2006 Dec; 108(6):1499-505.
[13.] Jarvis S, Glinianaia SV, Torrioli MG, Platt MJ, Miceli M, Jouk PS, Johnson A, Hutton J, Hemming K, Hagberg G, Dolk H, Chalmers J; Surveillance of Cerebral Palsy in Europe (SCPE) collaboration of European Cerebral Palsy Registers. Cerebral palsy and intrauterine growth in single births: European collaborative study. Lancet. 2003 Oct 4; 362(9390):1106-11.
[14.] Topp M, Huusom LD, Langhoff-Roos J, Delhumeau C, Hutton JL, Dolk H. Multiple birth and cerebral palsy in Europe: a multicenter study. Acta Obstet Gynecol Scand. 2004 Jun; (6):548-53.
[15.] Surman G, Hemming K, Platt MJ, Parkes J, Green A, Hutton J, Kurinczuk JJ. Children with cerebral palsy: severity and trends over time. Paediatr Perinat Epidemiol. 2009 Nov; 23 (6): 513-21.
[16.] Brooks JC, Strauss DJ, Shavelle RM, Tran LM, Rosenbloom L, Wu YW. Recent trends in cerebral palsy survival. Part I: period and cohort effects. Dev Med Child Neurol. 2014; Nov; 56 (11):1059-64.
[17.] Johnston MV, Hagberg H. Sex and the pathogenesis of cerebral palsy. Dev Med Child Neurol. 2007 Jan; 49(1):74-8.
[18.] Skiold B, Alexandrou G, Padilla N, Blennow M, Vollmer B, Aden U. Sex differences in outcome and associations with neonatal brain morphology in extremely preterm children. J Pediatr. 2014 May; 164(5):1012-8.
[19.] MacLennan A. A template for defining a causal relationship between acute intrapartum events and cerebral palsy: international consensus statement. International Cerebral Palsy Task Force. Aust N Z J Obstet Gynaecol. 2000 Feb; 40(1):13-21.
[20.] Ballot DE, Potterton J, Chirwa T, Hilburn N, Cooper PA. Developmental outcome of very low birth weight infants in a developing country. BMC Pediatr. 2012 Feb 1; 12:11.
[21.] Stoknes M, Andersen GL, Dahlseng MO, Skranes J, Salvesen KA, Irgens LM, Kurinczuk JJ, Vik T. Cerebral palsy and neonatal death in term singletons born small for gestational age. Pediatrics. 2012 Dec; 130(6):e1629-35.
[22.] Costeloe KL, Hennessy EM, Haider S, Stacey F, Marlow N, Draper ES. Short term outcomes after extreme preterm birth in England: comparison of two birth cohorts in 1995 and 2006 (the EPICure studies). BMJ. 2012 Dec 4; 345:e7976.
[23.] Nelson KB, Ellenberg JH. Antecedents of cerebral palsy. Multivariate analysis of risk. N Engl J Med. 1986 Jul 10; 315(2):81-6.
[24.] Yudkin PL, Johnson A, Clover LM, Murphy KW. Assessing the contribution of birth asphyxia to cerebral palsy in term singletons.
[25.] Ellenberg JH, Nelson KB. The association of cerebral palsy with birth asphyxia: a definitional quagmire. Dev Med Child Neurol. 2013 Mar; 55(3):210-6.
[26.] Lodha A, Sauve R, Chen S, Tang S, Christianson H. Clinical Risk Index for Babies score for the prediction of neurodevelopmental outcomes at 3 years of age in infants of very low birthweight. Dev Med Child Neurol. 2009 Nov; 51(11):895-900.
[27.] Surman G, Hemming K, Platt MJ, Parkes J, Green A, Hutton J, Kurinczuk JJ. Children with cerebral palsy: severity and trends over time. Paediatr Perinat Epidemiol. 2009 Nov; 23 (6):513-21.
[28.] Wadhawan R, Oh W, Vohr BR, Wrage L, Das A, Bell EF, Laptook AR, Shankaran S, Stoll BJ, Walsh MC, Higgins RD; Eunice Kennedy Shriver National Institute of Child Health & Human Development Neonatal Research Network. Neurodevelopmental outcomes of triplets or higher-order extremely low birth weight infants. Pediatrics. 2011 Mar; 127(3): 654-60.
[30.] Hustad KC, Allison K, McFadd E, Riehle K. Speech and language development in 2-year-old children with cerebral palsy. Dev Neurorehabil. 2014 Jun; 17(3):167-75.
[31.] Zafeiriou DI, Kontopoulos EE, Tsikoulas I. Characteristics and prognosis of epilepsy in children with cerebral palsy. J Child Neurol. 1999 May; 14(5):289-94.
[32.] Singhi P, Jagirdar S, Khandelwal N, Malhi P. Epilepsy in children with cerebral palsy. J Child Neurol. 2003 Mar; 18(3):174-9.
[33.] Vargha-Khadem F, Isaacs E, van der Werf S, Robb S, Wilson J. Development of intelligence and memory in children with hemiplegic cerebral palsy. The deleterious consequences of early seizures. Brain. 1992 Feb; 115 Pt 1:315-29.
[34.] Bruck I, Antoniuk SA, Spessatto A, Bem RS, Hausberger R, Pacheco CG. Epilepsy in children with cerebral palsy. Arq Neuropsiquiatr. 2001 Mar; 59(1):35-9.
Kulak P. (1) *, Maciorkowska E. (2), Goscik E. (1)
(1) Department of Pediatric Radiology, Medical University of Bialystok, Poland
(2) Department of Developmental Age Medicine and Paediatric Nursing, Medical University of Bialystok, Poland
* Corresponding author:
Department of Pediatric Radiology, Medical University of Bialystok
ul.Waszyngtona 17, 15-274 Bialystok, Poland
Tel.: +48 85 745 06 33
Table 1. Clinical data of children with cerebral palsy and children without cerebral palsy. Variable Children Children P value with without cerebral cerebral palsy n=92 palsy n=96 Boys/Girls 64/28 43/53 0.003 Gestational 35.96[+ or -]4.2 39.2[+ or -]1.4 <0.001 age (weeks) (26-42) (34-43) Number of 2.01[+ or -]1.5 2.09[+ or -]1.3 NS pregnancies (1-10) (1-6) Number of 1.9[+ or -]1.5 1.9[+ or -]1.1 NS deliveries (1-10) (1-6) Vaginal 61 (66.3%) 70 (72.9%) NS birth Cesarean 31 (33.7%) 26 (27.1%) NS section Prematurity 38 (41.3%) 5 (5.2%) <0.001 Weight at 2616[+ or -] 935 3343[+ or -]497 <0.001 birth (gram) (780-5060) (1900-4750) Agar score 5.9[+ or -]3.3 9.10[+ or -]1.5 <0.001 at 1 minute (1-10) (1-10) Mental development Normal 45 (48.9%) 96(100%) Small 20 (21.7%) Moderate 16 (17.4%) Severe 11 (12%) Epilepsy 27 (20.1%) 0 <0.001 Table 2. Psychomotor development of children with cerebral palsy and controls. Variable Children Children P value with without cerebral cerebral palsy n=92 palsy n=96 Sitting 1.1 [+ or -] 0.8 0.6 [+ or -] 0.25 <0.001 (0.6-3) (0.5-2) years years Standing 1.2 [+ or -] 0.9 0.97 [+ or -] 0.2 0.0045 (0.9-3.6) (0.9-2) years years Walking 1.5 [+ or -] 0.7 1 [+ or -] 0.3 (1- <0.001 (1-5) years 3) years Speech 1.4 [+ or -] 0.98 1.1 [+ or -] 0.4 0.003 (1-4) (1-3) Table 3. Correlations between variables and psychomotor development in children with cerebral palsy. Sitting Standing Variable R P value R P value Gender 0.127 0.227 -0.034 0.740 Number of pregnancies -0.107 0.306 -0.051 0.627 Number of deliveries -0.099 0.347 -0.014 0.894 Cesarean section 0.213 0.041 0.062 0.553 Week of pregnancy 0.151 0.149 0.006 0.951 Prematurity -0.173 0.097 -0.028 0.786 Apgar score at 1 minute 0.301 0.003 0.119 0.255 Asphyxia -0.302 0.003 -0.078 0.459 Weight at birth 0.200 0.055 -0.033 0.750 Epilepsy -0.315 0.002 -0.289 0.005 Mental retardation -0.420 0.000 -0.478 0.000 Walking Speech Variable R P value R P value Gender 0.067 0.524 -0.046 0.660 Number of pregnancies -0.110 0.294 0.028 0.789 Number of deliveries -0.044 0.671 -0.051 0.623 Cesarean section 0.063 0.550 0.058 0.581 Week of pregnancy 0.075 0.473 0.029 0.782 Prematurity -0.063 0.547 -0.022 0.832 Apgar score at 1 minute 0.171 0.101 0.112 0.284 Asphyxia -0.128 0.225 -0.127 0.229 Weight at birth 0.124 0.238 0.029 0.781 Epilepsy -0.301 0.003 -0.080 0.449 Mental retardation -0.617 0.000 -0.221 0.034 R--Spearman's rank correlation coefficient
|Printer friendly Cite/link Email Feedback|
|Author:||Kulak, P.; Maciorkowska, E.; Goscik, E.|
|Publication:||Progress in Health Sciences|
|Date:||Dec 1, 2014|
|Previous Article:||Satisfaction with obstetric care in the early postnatal period.|
|Next Article:||Erythrocyte functional status and lipid profile of coal mine workers of West Bengal, India.|