Functional performance of children with cerebral palsy from high and low socioeconomic status

Objective: To investigate the influence of socioeconomic status on the functional performance of children with cerebral palsy. Methods: Cross-sectional quantitative study of 49 children diagnosed with cerebral palsy from a convenience sample. Children of both genders aged three to seven and a half years were studied. They were classified according to the level of severity of cerebral palsy based on the Gross Motor Function Classification System. Participants were organized in two groups considering their high or low socioeconomic status, according to the Brazilian Economic Classification Criteria. Functional performance was assessed by the Pediatric Evaluation of Disability Inventory. The Student’s t-test was applied for independent samples in order to compare means between groups. Results: Socioeconomic status did not affect functional performance of children with mild cerebral palsy. Those with moderate cerebral palsy and low socioeconomic status presented lower social function scores (p=0.027) than those with high socioeconomic status. Children with severe cerebral palsy with low socioeconomic status presented worse performance in self-care skills (p=0.021) Endereço para correspondência: Elisângela Andrade Assis Madeira Rua Pastor Valdomiro Oliveira, 737 – Candeias CEP 45028-742 – Vitória da Conquista/BA E-mail: eli.madeira@yahoo.com.br Fonte financiadora: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes) e Fundo Mackenzie de Pesquisa (MackPesquisa) Conflito de interesse: nada a declarar Recebido em: 8/5/2012 Aprovado em: 24/9/2012


Introduction
Child development is composed of several interdependent domains (sensorimotor, cognitive and socio-emotional), which can be influenced by biological (gestational age and birth weight), environmental (economic status and parents' education), and hereditary factors, which can be affected by adverse or favorable situations (1) .When these factors bring negative consequences to the child's development, they are called risk factors.Among these are family characteristics, which can pose a greater risk to the healthy development of children (2,3) .
Motor development is a process of change in behavior as a result of the interaction of heredity with the environment.In this process, it is considered that the environment causes a stimulatory effect that interacts with human biology, producing the behavior (4) .For De Barros et al (5) , the early identification of possible risk situations that may affect the course of development is important to prevent damage throughout life.
Some studies show the relationship between low socioeconomic status and developmental impairment of children (1,(6)(7)(8) .They suggest that the low socioeconomic status (SES) may increase the child's biological vulnerability, leading to unfavorable outcomes in development.Unfortunately, the population that accumulates risk factors that may affect the development is, almost always, the most disadvantaged, increasing, thereby, the chances of developmental delay.
The caregiver's education and the family income are basic elements to determine the child's health, because they are indicators of available resources, and knowledge or behavior in relation to health and well-being of children (9) .SES may impact on the well-being of children with cerebral palsy (CP), with distinction between high and low levels of economic classes in relation to functional abilities and independence.According to Schenker et al (10) , the development of motor skills of children with CP presents a characteristic delay.Therefore, basic motor skills can be acquired later in childhood, generating a difference of years of delay, compared with healthy children regarding gross motor skills.In this sense, the functional manifestations of children with CP should be evaluated, once the functional performance is influenced not only by the intrinsic properties of the child, but also by the specific demands of the task and the characteristics of the environment in which it interacts (11,12) .
The relationship between SES and CP is not yet clear, however, it is believed that this association may suggest etiological factors and ways for prevention (13) , as well as impairments to motor development.Knowledge of the CP motor performance, from the analysis of the socioeconomic context, may represent an important tool for decision making in resource management and in the planning of services for these children.Based on the literature, the present study aimed to investigate possible relations between the functional performance of children with CP with different degrees of commitment and the family's SES.

Method
This was a cross-sectional descriptive study of public and private institutions in the metropolitan area of Vale do Aço, in the state of Minas Gerais.The research project was previously approved by the Research Ethics Committee of Universidade Presbiteriana Mackenzie under no.1134/04/2009, meeting the requirements of the Resolution 196/96 of the National Health Council's team.The informed consent term was obtained from the legal guardian of the participants, after taking part in the study voluntarily.Data collection was performed at the institution/clinic where the child was assisted in a private room.
Inclusion criteria were: children with clinical diagnosis of any kind of CP and non-evolutionary chronic encephalopathy (NECE), from both sexes, with chronological age between 3 to 7 and a half years; classified between levels I, II, III, IV and V in the System of Classification of the Gross Motor Function.For children under anticonvulsants, the study included those without seizures for at least 3 months.The study excluded subjects with congenital malformation unrelated to CP, severe sensory deficit, and chromosomal diseases, children submitted to the surgery of the musculoskeletal system and/or the application of botulin toxin type A in less than 6 months.
Participated in this study the primary caregiver of the child, responsible for the well-being, health and care; who would have to live or spend most of the day with the child (at least part-time) and provide daily care for at least 6 months.No sample size calculation was performed, because the aim was to collect data on children with CP who were in rehabilitation and public and private institutions that met the inclusion criteria to participate in the research.Therefore, we used convenience sampling and 49 children with CP were selected.
A form was used to identify data that included the child (age, date of birth, birth weight, names of father and mother, gestational age, presence of neonatal complications and epilepsy, school attendance) and the caregiver (age, degree of kinship with the child, address, telephone number, marital status, education level and occupation).Children were classified by the same evaluator according to the severity of CP, based on the GMFCS (14)(15)(16) .This instrument stratifies children with CP at levels I, II, III, IV and V. Patients were grouped into three levels of involvement, according to studies that have also used these systems (16,17) .The children classified in levels I and II were considered mild; level III, moderate; and those in levels IV and V, severe.Participants were also divided into two groups according to the economic class of the family (high and low), according to the Economic Classification Criterion of Brazil (18) .Socioeconomic categories range from A (very high) to E (very low), and the remaining are intermediate categories (B, C, D).For the study it was found that categories A and B belonged to the high SES, and categories C, D and E, to the low, according to the classification adopted by Mancini et al (19) .The final distribution of the groups was as follows: children from high SES (mild, moderate and severe CP) and children from low SES (mild, moderate and severe CP).
The Brazilian version of the Pediatric Evaluation of Disability Inventory (PEDI) was applied to analyze functional performance.This test is divided into three distinct parts, that inform about three areas of functional performance.This study used only parts I and II; the third part, about changes in the environment, was not performed.The first part documents the functional skills of the child in the following scales: self-care, mobility and social function.Each item receives score 1 if the child is able to perform the activity, or 0 if it is not able to perform it.The total scores on each scale of this part results in a total gross score for each of the three areas of functional skills.The second part of the PEDI quantifies the help provided by the caregiver to the child to accomplish tasks of: self-care, mobility and social function.In this part of the test, the assistance is evaluated on an ordinal scale, including categories: 0 (total assistance), 1 (maximum assistance), 2 (moderate assistance), 3 (minimal assistance), 4 (supervision) and 5 (independent).The test manual provides specific criteria for scoring each item.In this study we used the raw data from the PEDI (20) .
Data were analyzed using descriptive and inferential statistics.To perform statistical analysis, the software Statistical Package for the Social Sciences for Windows (SPSS), version 11.0 was used.Quantitative variables were described by mean and standard deviation.To verify normality of the data, we Functional performance of children with cerebral palsy from high and low socioeconomic status t test for independent samples was applied to compare means between groups.The level of significance was set at 5.

Results
The 49 children were distributed according to social class and severity of CP into six distinct groups: Group 1 (n=8), for those who had mild CP and families in social classes A and B (high SES); Group 2 (n=8), mild CP from families that applied the Kolmogorov-Smirnov test, accepting p>0.05.Quantitative variables were presented by absolute and relative frequencies.Descriptive analyzes comparing groups (mild, moderate and severe CP) were performed with analysis of variance (ANOVA) for quantitative (age) and chi-square test for categorical variables (gender and SES).Multivariate analysis was used to investigate the effects of interaction between SES and the severity of CP in functional performance (three CP severities with two SES), assuming an alpha of 5%.Student's In multivariate analysis there was no interaction effect between severity of CP and SES (p=0.141),t test was used to compare the functional performance of the children surveyed between the upper and lower economic classes.Regarding the functional skills of children with mild CP (Table 2), we compared the high and low socioeconomic classes, however, there were no significant differences between these groups.It was observed that the groups showed equivalent performance in caregiver assistance in self-care (p=0.392),mobility (p=0.788) and social function (p=0.167),i.e., no significant difference was observed in such areas in both SES.
The functional skills of children with moderate CP were also equivalent in low and high SES, i.e., no significant differences were found.However, caregiver assistance in participants of low social class had scores for social function (p=0.027)significantly lower than those of upper class, i.e., children of high SES showed more independence in social function that those of low SES.
For functional skills of self-care (p=0.021) and mobility (p=0.005) in children with severe CP, when groups of high and low SES were compared, significant differences were observed, with lower performance in self-care and mobility skills in children of low socioeconomic class.When checking the independence in mobility (p=0.014),low SES children receive more help from their caregivers than those of high SES, however, no difference was observed in the independence of self-care (p=0.407) and social function (p=0.098),indicating that in both groups (high and low SES) children need equivalent assistance.
Table 3 shows the comparison between high and low socioeconomic status in functional skills and caregiver assistance, regardless of severity of the condition.In relation to self-care, differences were found in functional ability (0.027) and independence (0.032) of children, i.e., individuals of low SES underperformed when compared to those of high SES.The same occurred regarding social function, in which the participation of low SES children in social activities was lower than those of high SES.However, there were no significant differences in mobility between the two classes.

Discussion
According to data obtained in the present study, the SES of children with mild CP does not seem to affect their functional performance.Seeking clarity on issues like this, Andrade et al (21) reported that in the process of rehabilitation of the child, the SES of the family may be a barrier or a facilitator, i.e., in this process of acquisitions of new skills this may be a deciding factor.To Bracco et al (22) , the low SES may cause an inactive behavior of children, related to restricted alternatives for leisure and culture.On the other hand, Malina and Bouchard (23) verified that children with low SSE live in an environment with more freedom of movement, with more opportunities to experience a varied motor repertoire.
Regarding the social function of individuals analyzed, children with varied involvement (mild, moderate and severe) showed similar performance.However, when analyzing caregiver assistance on the same basis, those with moderate CP and low SES were more dependent than children with high SES, indicating that despite presenting the necessary skills, they continued to receive help from their caregivers.The socialization of these children depends on the family playing the role of mediator between the child and society (24) , providing adequate support, when needed, for the individual to join the group in which he was born, acquiring its characteristic habits and values .Families from distinct SES may have different expectations about the independent performance of children with CP.Therefore, there may be a difference in the amount of aid that caregivers provide to these children.The excessive aid makes the child more dependent, even if it presents conditions to perform certain tasks.To better elucidate such questions, Bradley and Corwyn (25) reported that, in the family environment, the child could receive appropriate assistance to cope with risks to their development.In this case, the excessive aid of the caregiver could become a risk for the development, as well as an overload to the caregiver.Camargo et al (26) , in a study on caregivers of children with CP, found a greater overload among those who were in unfavorable socioeconomic conditions, i.e., the lower the SES, the greater the caregiver's burden.
The risk of belonging to an economically disadvantaged family seems to affect more children with severe CP, i.e., with greater biological risk.This occurred mainly in mobility, in which both the ability and independence were lower in children with low SES.Regarding self-care, although these children have lower ability than high SES children, the caregiver assistance on the same task was similar in both economic classes.This seems to indicate that when it comes to children with severe conditions, families of high socioeconomic status are more overprotective than those of low SES.The excessive aid by the caregiver can occur for several reasons; one of them is that the caregiver underestimates the child's ability to perform activities and ultimately accomplishes the tasks, creating greater dependence.Shonkoff and Meisels (27) argue that caregivers of children with more severe sequelae, such as in the case of severe CP, exert a dominant role for a long period in the interaction between caregiver and child.
In general comparison of functional performance, without considering motor impairment, it was observed that families of high socioeconomic class provide more opportunities for the development of functional self-care than those of low socioeconomic class.This finding corroborates the study by Halpern et al (7) , which found that children from low SES families were twice as likely to present a delay in their neurodevelopment compared to those with higher SES.A study by Dowding and Barry (28) , proved that the social class affected the most severe cases of CP.
Mancini et al (19) mentioned that "the high SES of families is related to certain favorable conditions, such as greater parental education, greater access to information, and greater purchasing power."With the increase in family income, parents become more able to pay attention and invest in their children, following the guidance of health and education professionals (29) .On the other hand, people with unfavorable socioeconomic conditions, expressed through maternal/paternal unemployment and unavailability of consumer goods, have children with delayed development (30) .One must consider the different contexts to which these children are exposed to standardize the assessment of functionality, taking into account environmental factors, because the SES is the most important environmental reason that may contribute to the rehabilitation process (21) .Because of the multifactorial and dynamic nature of child development and poverty, the attempt to compare data from study results that explain the association between these two elements is complex (30) , and the methodology used to evaluate both the SES and child development is not uniform among the various studies (1,5,6,8,(30)(31)(32) .
The results presented contribute to a better understanding of the development of children with CP, especially those who are in different socioeconomic conditions.However, some limitations were found, since the sample was reduced and restricted to children with CP attending rehabilitation programs in specialized institutions.Moreover, there was the difficulty of finding children in the region with severe CP of high SES, resulting in a reduced number of members in this group.
It is suggested from this study that the SES can influence the severity of the disease and the development of children with cerebral palsy, so it should be considered as a risk factor in educational and health actions aimed at this population.Longitudinal studies could contribute to more accurate information, bringing prospects of greater impact on public policy, with proposals aimed at prevention and rehabilitation sectors in Brazil.

Table 2 -
Comparison of functional skills and caregiver assistance for children with mild, moderate and severe cerebral palsy, of low and high economic class

Groups Socio-economic Level p-value High Low
FS: functional skills; CA: caregiver assistance SES: socio-economic status; SD: standard deviation

Table 1 -
Descriptive analysis of severity groups of children with cerebral palsy

Table 3 -
General comparison of functional skills and caregiver assistance between high and low socioeconomic classes *mean±standard deviation; FS: functional skills; CA: caregiver assistance