Cerebral palsy (CP) is an umbrella term encompassing a group of nonprogressive, noncontagious neurological conditions that cause physical and cognitive disability in human development and affect functional performance, participation, movement, strength, posture, muscle tone, sensation, vision, perception, communication, and behavior (Ashwal et al., 2004). CP is caused by damage to the motor control and cognitive centers of the developing brain and can occur during pregnancy (approximately 75%), during childbirth (approximately 5%), or after birth (approximately 20%; Thorngren-Jerneck & Herbst, 2006). The incidence of CP is approximately 2 per 1,000 live births in industrialized countries; incidence is higher in boys than in girls (Pharoah, 2007; Strauss, Brooks, Rosenbloom, & Shavelle, 2008).

Because of the challenging clinical presentation in children, adolescents, and young adults with CP, occupational therapy practitioners and other health care providers must use the best available evidence to optimize functional outcomes for these clients. Yet, the base of evidence for predicting self-care, mobility, and social function is limited to a few research studies, many with small sample sizes. One study, for example, found that functional skill development varied depending on the level of physical and cognitive impairment (Iyer, Haley, Watkins, & Dumas, 2003). Most studies had a small, homogeneous sample and focused on children ages 2–7 yr (Ahl, Johansson, Granat, & Carlberg, 2005; Dumas, Haley, & Ludlow, 2008; Harvey, Robin, Morris, Graham, & Baker, 2008; Ketelaar, Vermeer, Hart, van Petegem-van Beek, & Helders, 2001; Novak, Cusick, & Lowe, 2007; Oeffinger et al., 2007; Ostensjø, Carlberg, & Vøllestad, 2003; Pirila, van der Meere, Seppanen, Korpela, & Nieminen, 2006; Schoenmakers, Gulmans, Gooskens, & Helders, 2004; Voorman et al., 2006; Wright, Rosenbaum, Goldsmith, Law, & Fehlings, 2008). In addition, these studies did not focus on the prediction of functional performance in self-care, mobility, and social function and level of caregiver assistance for large samples to predict functional changes by type and severity of CP and by age. Ostensjø and colleagues (2003)  predicted self-care, mobility, and social function by severity of CP for 95 children ages 2–7 yr. The current study includes 2,768 children, adolescents, and young adults ages 0–19 yr to provide needed evidence for optimal therapy treatment planning, caregiver education, and clinical resource allocation.

We used a retrospective longitudinal cohort design for children, adolescents, and young adults with a medical diagnosis of CP from a large network of pediatric outpatient rehabilitation clinics at the California Children’s Services Medical Therapy Program in the Los Angeles County Department of Public Health. This methodology enabled us to investigate research questions regarding the effects of CP on self-care, mobility, and social function and level of caregiver assistance, by type and severity of CP, for a large sample of children, adolescents, and young adults. Self-care activities include eating, grooming, bathing, dressing, and toileting. Mobility activities include transfers and locomotion. Social function activities relate to communication, peer interaction, and social participation.

The study sample consisted of children, adolescents, and young adults ages 0–19 yr with five primary types of CP: hemiplegia, tetraplegia, diplegia, ataxia, and athetoid; some had mixed types. People with hemiplegia tend to have motor deficits on one side of the body (upper and lower limbs); people with tetraplegia have motor deficits in all four limbs of the body; people with diplegia have motor deficits in the lower extremities with little to no upper-limb deficits; people with ataxia have damage to the cerebellum causing hypotonia, tremors, and poor balance; and people with the athetoid type of CP have mixed muscle tone throughout the body, causing involuntary motion (Hirtz et al., 2007; Johnson, 2002).

The sampling method for this study was a convenience sample because of the retrospective nature of the data analysis. Inclusion criteria included age of 0–19 yr and medical diagnosis of CP. Children, adolescents, and young adults with diagnoses other than CP or whose diagnoses were undetermined were excluded from the study. Adults with CP older than age 19 were also excluded from the study.

The Pediatric Evaluation of Disability Inventory (PEDI) is a reliable and valid functional outcome measurement tool that was designed to measure function and level of caregiver assistance in self-care, mobility, and social function (Haley, Coster, & Faas, 1991; Haley, Coster, Ludlow, Haltiwanger, & Andrellos, 1992; Nichols & Case-Smith, 1996). Concurrent validity is supported by moderately high Pearson product–moment correlations (rs = .70–.80), and construct validity is supported by significant differences between the PEDI scores of respondents with and without disability (Feldman, Haley, & Coryell, 1990). The instrument measures 197 functional skills (73 items for self-care, 59 items for mobility, and 65 items for social function); functional activities are rated 1 (performed in most situations) or 0 (not performed in most situations), and level of caregiver assistance measured in 20 functional areas is rated on a scale ranging from 5 (independence) to 0 (total assistance).

The Gross Motor Function Classification System (GMFCS) is a reliable (interrater reliability = .84) and valid five-level ordinal classification system for measuring the age-related severity of gross motor limitations from CP (Bodkin, Robinson, & Perales, 2003; Palisano et al., 2000; Palisano, Rosenbaum, Bartlett, & Livingston, 2007; Wood & Rosenbaum, 2000). The classification levels are as follows: Level 1, walks without limitations; Level 2, walks with limitations; Level 3, walks using a hand-held mobility device; Level 4, self-mobility with limitations; and Level 5, transported in a manual wheelchair. These internationally recognized classification levels provide a determination of the gross motor function and severity of disability. We categorized each participant on the GMFCS using the established criteria for each classification level.

The Manual Ability Classification System (MACS) is a reliable and valid five-level ordinal classification system for measuring the severity of upper-extremity and fine motor dysfunction for people with CP. It has an intraclass correlation coefficient between therapists of .97 (95% confidence interval [CI] = .96, .98) and between parents and therapists of .96 (95% CI = .89, .98; Eliasson et al., 2006). The classification levels are as follows: Level 1, handles objects easily and successfully; Level 2, handles most objects, but with reduced quality and/or speed of movement; Level 3, handles objects with difficulty, needing assistance to prepare and/or modify activities; Level 4, handles a limited selection of easily managed objects in adapted situations; and Level 5, does not handle objects and has severely limited ability to perform even simple actions. We categorized each participant on the MACS using the established criteria for each classification level.

We obtained approval for this research project from the institutional review board of the Los Angeles County Department of Public Health. We collected data through a chart review methodology using existing medical records. Before beginning data entry, we removed identifying information, including the name and the patient identification number, and gave the forms a data sequence number in the SPSS (Version 18.0; SPSS, Inc., Chicago) database to protect patient confidentiality. This study adhered strictly to all federal Health Insurance Portability and Accountability Act (HIPAA) standards as well as to state and county privacy laws and regulations.

Occupational therapists and physical therapists administered and scored the PEDI as part of a comprehensive therapy evaluation process. Occupational therapists and physical therapists evaluated functional performance through observation for each of the 197 functional skills. Level of caregiver assistance was evaluated through a caregiver interview consisting of 20 functional items; for each item, the therapist asked the caregiver to describe the amount and type of assistance provided to the child in his or her natural environment. Standard procedures described in the PEDI evaluation manual were used. If the caregiver spoke a language other than English as the primary language, the PEDI was administered in that language. If any of the scores for the 73 self-care items, 59 mobility items, and 65 social function items or any of the 20 items for level of caregiver assistance were missing from the data, we could not reliably determine a composite raw score for that particular PEDI subsection, so we did not enter a raw composite score from that assessment area for analysis.

We confirmed the accuracy of each participant’s medical diagnosis (including type of CP), as determined by the child’s physician, as well as age, gender, ethnicity, residence, school placement, therapy evaluator, Los Angeles County Service Planning Area (SPA), and caregivers’ years of education and selected forms that met the inclusion criteria. Severity of CP was determined through GMFCS and MACS scores obtained through therapist observation of global gross motor and fine motor skills.

Independent variables factored into the data analysis included type and severity of CP as measured by GMFCS and MACS scores. Covariates factored into the analysis included age, gender, ethnicity, residence, school placement, discipline of evaluator, SPA, and caregivers’ years of education. Dependent variables included functional skill level scores for self-care, mobility, and social function and level of caregiver assistance in the domains of self-care, mobility, and social function using PEDI composite scores.

Univariate analysis included frequencies and percentages (type and severity of CP, gender, ethnicity, place of residence, school placement, discipline of therapy evaluator, and SPA) and means (PEDI composite scores, age, and caregivers’ years of education) to describe the demographic characteristics of the sample and the distribution of associations with the variables. Multiple linear regression was used to predict the effects of CP on self-care, mobility, and social function and level of caregiver assistance in self-care, mobility, and social function by CP type and severity. Age, gender, ethnicity, residence, school placement, discipline of therapy evaluator, SPA, and caregivers’ years of education were also factored into the regression model to determine whether these covariates had a significant effect on self-care, mobility, and social function.

A total of 2,768 children with CP were evaluated using the PEDI in a large urban pediatric outpatient rehabilitation program. Demographic characteristics of the children in the sample are summarized in Table 1. The mean age of the participants was 4.3 yr (SD = 2.3). Caregiver education averaged 12.0 yr (SD = 3.9). The sample had a higher percentage of boys (56.6%) than girls (43.4%) and was predominantly Hispanic (55.9%). In addition, 93.1% of the children lived at home with their caregivers and attended preschool (21.3%) or elementary school (16.0%).

The type of CP was determined by the physician’s medical diagnosis, which included CP Tetraplegia, CP Hemiplegia, CP Diplegia, CP Ataxia, CP Athetoid, and CP Mixed. Higher percentages of CP Mixed, CP Tetraplegia, CP Hemiplegia, and CP Diplegia and lower percentages of CP Ataxia and CP Athetoid were found in this sample. CP severity was determined through GMFCS scores; scores of 1 and 5 were the most frequent; scores of 2, 3, and 4 were distributed evenly throughout the sample. MACS scores also indicated CP severity; scores of 4 and 5 had a higher frequency in this sample.

The mean scores for the dependent PEDI variables of Self-Care (Functional Skills), Mobility (Functional Skills), Social Function (Functional Skills), Self-Care (Caregiver Assistance), Mobility (Caregiver Assistance), and Social Function (Caregiver Assistance) are summarized in Table 2. Scores for each subsection were similar. Self-Care had the highest score for Functional Skills, and Mobility had the highest score for Caregiver Assistance.

Multiple linear regression was used to develop models for predicting which factors had the most effect on self-care, mobility, social function, and level of caregiver assistance. Table 3 summarizes the multivariate models for prediction of Self-Care (Functional Skills), Mobility (Functional Skills), Social Function (Functional Skills), Self-Care (Caregiver Assistance), Mobility (Caregiver Assistance), and Social Function (Caregiver Assistance). Severity of CP and age significantly predicted self-care, mobility, and social function.

The model explained a significant proportion of variance in Self-Care (Functional Skills) scores, R²= .8, F(3, 2768) = 2,653.7, p < .001; Mobility (Functional Skills) scores, R²= .8, F(3, 2768) = 2,653.7, p < .001; Social Function (Functional Skills) scores, R²= .8, F(3, 2768) = 783.4, p < .001; Self-Care (Caregiver Assistance) scores, R²= .8, F(3, 2768) = 1,271.4, p < .001; Mobility (Caregiver Assistance) scores, R²= .8, F(3, 2768) = 1,795.8, p < .001; and Social Function (Caregiver Assistance) scores, R²= .6, F(3, 2768) = 564.9, p < .001. Type of CP, gender, ethnicity, residence, school placement, discipline of therapy evaluator, SPA, and caregivers’ education were not significant predictors of self-care, mobility, and social function.

This study provides evidence of the relationship between self-care, mobility, and social function and severity of CP. The findings can benefit children, adolescents, and young adults with CP and their caregivers by providing evidence to support treatment planning and intervention on the basis of CP severity, as measured by the GMFCS and the MACS and age of the child. Therapists can thus use CP severity and age of the child in estimating the child’s potential self-care, mobility, and social function levels and developing meaningful treatment plans and goals. Medical diagnosis (type of CP) was not a significant predictor of self-care, mobility, or social function.

Treatment planning guidelines for therapists by CP severity are in development. For example, a recent study defined the level of home and community activities among children with CP by GMFCS and MACS scores (Orlin et al., 2010). Another study, which took into account patient and family goals and gross motor and manual abilities, provided evidence that intensive therapy services aimed at reducing activity limitations in children with CP resulted in higher levels of self-care, mobility, and social function (Ketelaar et al., 2001). The current study can inform the development of more specific therapy treatment planning guidelines for specific self-care, mobility, and social function skills by severity and age that can be further tested to provide recommendations for the frequency and intensity of therapy services for children, adolescents, and young adults with CP.

Severity of CP and age also had strong effects on level of caregiver assistance with self-care, mobility, and social function skills, as measured by the GMFCS and the MACS; a more severe level of gross motor and fine motor dysfunction resulted in a higher level of caregiver burden. This evidence can be used to develop caregiver guidelines for effective management of a child, adolescent, or young adult with CP on the basis of GMFCS score, MACS score, and age. Meaningful functional descriptions can be developed to enhance communication and coordination between the therapist and caregiver and to prepare caregivers for effective daily management and support of their child with CP. Educational brochures and manuals can be created to improve caregiver education and provide supportive suggestions for maximizing the child’s function in the home, community, and school environments. In addition, these materials can be used to provide more effective community resources and home programs to reinforce self-care, mobility, and social function skills learned in therapy in the child’s natural environment. Family-centered guidelines by GMFCS score and MACS score are in development, but more research is needed to determine the validity of caregiver recommendations (Morris, Kurinczuk, Fitzpatrick, & Rosenbaum, 2006).

In addition to providing guidelines for therapist intervention and caregiver education, the results of this study have implications for clinical resource utilization. Severity of CP and age can be used to ensure equitability across therapist caseloads, and data can be gathered on the cost of providing therapy services to patients with CP by severity level and age and to develop protocols for more effective and equitable treatment. Self-care, mobility, and social function outcomes can then be prospectively measured over time to determine the effectiveness of therapy treatment of patients with CP. Studies are showing the benefit of intensive therapy for children with CP, but further research is needed to assess the effectiveness of therapy programs targeted at specific self-care, mobility, and social function skills by severity and age (Yabunaka et al., 2011).

Because this study used a retrospective cohort design and included children, adolescents, and young adults with CP from a specific geographic location with diverse ethnic and cultural backgrounds, the ability to generalize the results or to assign causality is limited. With the exception of a higher proportion of Hispanic participants in this study, however, the demographics of the sample were similar to those reported in other areas of the United States (Kirby et al., 2011). We included no controls for comorbidities, spontaneous recovery, cognitive functioning, locus of brain lesions, or amount and type of therapy provided. Each participant was provided a unique occupational therapy and physical therapy treatment program on the basis of his or her rehabilitation potential, patient and family goals, and level of participation, all characteristics that were not well documented on the PEDI evaluation forms. In addition, the retrospective dataset resulted in a convenience sample; the lack of randomization further limits the generalizability of the study results. Interrater reliability was not established among the occupational therapists and physical therapists administering the PEDI instrument. In addition, for ease in data handling we examined composite scores for self-care, mobility, and social function and level of caregiver assistance on the PEDI rather than individual scores for each of the 197 functional skills.

Future research should use a prospective, randomized, and controlled methodology. A multisite study could control for geographic representation. In addition, future research should control for comorbidities, spontaneous recovery, cognitive functioning, and locus of brain lesions. Interrater reliability should be established for all clinicians participating in data collection. Future research should continue to investigate the effectiveness of therapy intervention in improving self-care, mobility, and social function for children, adolescents, and young adults with CP.

The results of this research have the following implications for occupational therapy practice:

• CP type (medical diagnosis) did not have a significant effect on self-care, mobility, and social function. CP severity, however, had the strongest effect, as measured by the GMFCS and the MACS. A more severe level of gross motor and fine motor dysfunction resulted in a lower level of self-care, mobility, and social function for both functional skills and level of caregiver assistance.

• Age was a significant predictor of self-care, mobility, and social function. Functional skills increased and level of caregiver assistance decreased as the children aged.

The purpose of this research was to determine whether the type and severity of CP had an effect on functional performance and level of caregiver assistance in self-care, mobility, and social function for children, adolescents, and young adults with CP ages 0–19 yr. This study provides a critical foundation of evidence regarding the importance of severity of CP as a significant predictor of self-care, mobility, and social function. The findings can be tested in future research to improve therapy treatment planning, caregiver education, and clinical resource utilization.

We acknowledge the following people for their support of this research study: Angela Hegamin, Heidi Sato, Frank Gomez, Mihaela Tanasescu, Afshin Afrookhteh, Wendy Coster, Jane Moore, Deblia Craddock, Gail Monti, Debra Ruge, Wesley Ford, Edward Bloch, Lora Woo, Eunice Shen, Sydney Roth, Walton Senterfitt, Sergio Sandoval, the American Occupational Therapy Foundation, the California Foundation for Occupational Therapy, and the patients and staff of the California Children’s Services Medical Therapy Program in the Los Angeles County Department of Public Health.