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A Pilot Study of Quality of Life in Children with Cerebral Palsy After Intensive Body Weight-Supported Treadmill Training

Dieruf, Kathy PT, PhD; Burtner, Patricia A. OTR/L, PhD; Provost, Beth PT, PhD; Phillips, John MD; Bernitsky-Beddingfield, Ann PT; Sullivan, Katherine J. PT, PhD

doi: 10.1097/PEP.0b013e31818ec835
Research Report

Purpose: This pilot study was designed to examine the effects of a 2-week program of intensive body weight-supported treadmill training (BWSTT) on clinical measures of perceived health-related quality of life and fatigue in children with cerebral palsy.

Methods: Six children with spastic cerebral palsy (aged 6–14 years; all classified as Gross Motor Function Classification System Level I) received two 30-minute sessions of BWSTT daily for 2 weeks, and completed questionnaires preintervention and postintervention.

Results: Ratings by children and their parents who completed the Pediatric Quality of Life Inventory™ and Multidisciplinary Fatigue module resulted in nonsignificant higher mean postscores. However, of the children with complete data, 4 showed minimal clinically important differences by child and parent-proxy report.

Conclusions: Results suggest that positive health-related quality of life changes can be identified after an intensive intervention of BWSTT, and should include ratings from both children and parents.

Results suggest that positive Health Related Quality of Life changes can be identified following an intensive intervention of BWSTT and should include ratings from both children and parents.

Physical Therapy Graduate Program (K.D., B.P.), Department of Orthopaedics, University of New Mexico, Albuquerque; Occupational Therapy Graduate Program (P.A.B.), Department of Pediatrics, University of New Mexico, Albuquerque; Department of Neurology (J.P., A.B.-B.), University of New Mexico, Albuquerque; and Department of Physical Therapy and Biokinesiology (K.J.S.), University of Southern California, Los Angeles

Address correspondence to: Kathy Dieruf, PT, PhD, Physical Therapy Graduate Program, MSC09 5230, 1 University of New Mexico, Albuquerque, NM 87131-0001. E-mail:

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Historically clinical research trials have investigated the effect of a treatment on the physiologic aspects of a chronic disease or disability with little attention paid to treatment effect on the person's day to day satisfaction or health-related quality of life (HRQOL).1 With an increase in the variety of treatments and treatment schedules available, an enhanced interest in HRQOL of individuals with disabilities is noted in the literature.2–6 Several researchers have noted that children with cerebral palsy (CP) have lower HRQOL than healthy children, with more severely impaired children (ie: those with quadriplegia) reporting lower HRQOL than those with less significant impairments.5–8 However, the HRQOL relationship with level of physical impairment is only consistent with the domain of physical well-being; the psychosocial well-being domain does not consistently vary by functional level.6,7

When evaluating the effect of new interventions for children with CP, current practice incorporates assessments across all domains of the International Classification of Functioning, Disability, and Health. The International Classification of Functioning, Disability, and Health describes how people live with their health condition, and is a classification of health and health-related domains that describe body functions and structures, activities, and participation.1 This approach moves assessment beyond the impairment level to measure the effect of intervention on the activities in which the child engages and the participation of the child in society.9 In addition, the effect of the intervention on the child's well-being, quality of life (QOL), and health as well as the effect on his/her family must also be taken into account.

Until recently, clinical measures have relied heavily on parent-proxy report to assess an individual child's HRQOL.10,11 Some researchers find the use of proxy is an appropriate substitution, whereas others feel it is a very poor match. Meeske et al12 concluded that a medium to strong concordance between parent and child reports indicates that parents serve as a valid proxy for their child's HRQOL, particularly when the child is unable to report for him/herself. In contrast, others have found large differences between the child and the proxy scores and recommend that proxy reports be conducted only with the understanding that proxy ratings of a child's HRQOL may not accurately reflect the child's point of view.11,13,14 The accuracy of proxy score is often related to the specific domain being rated. Several authors have noted that parents are better able to judge the child's HRQOL in observable domains such as physical functioning and are less accurate when rating nonobservable domains, such as social or emotional HRQOL.15–17 An alternative view is that both parent proxy and self-report provide unique and complementary information concerning the child's HRQOL. Thus, both reports can be useful in clinical decision making. In addition, while HRQOL is a subjective domain, parent perceptions of their child's HRQOL are important because they often drive pediatric healthcare decisions and program development.12,16

Body weight-supported treadmill training (BWSTT) is a relatively new intervention currently being used with adults and children with a variety of neurologic impairments that affect mobility. Several studies have demonstrated the effectiveness of this intervention in adults with stroke18 and spinal cord injury.19 More recently, BWSTT has also been shown to be a promising intervention for children with CP for improving different parameters of gait.20–22 These interventions have been of varying frequency and duration and gait changes have been noted in some children in short time periods. Provost et al22 recently reported positive gait changes in children at Gross Motor Function Classification System (GMFCS)23 level I after an intensive 2-week intervention. Children with CP who are independent ambulators often have mobility and gait impairments that need to be addressed in physical therapy. Jahnsen et al24 investigated locomotion skills in adults with CP and found that 44% reported deterioration in walking skills, mainly before 35 years of age. This deterioration may be preventable if an ongoing program of effective treatment strategies is included as they mature.

None of the studies on BWSTT with children have reported the effect of these interventions on the children's health, well-being, and QOL. The aim of this pilot study was to examine the effects of a 2-week program of intensive BWSTT on clinical measures of perceived HRQOL and fatigue in the same sample studied by Provost et al.22 This type of intensive intervention might be useful as an option in several situations including for those living in rural areas with limited access to therapy and for those children and families who prefer a shorter but more intense intervention due to time commitments. Because the intervention was very intense, the authors surmised that the measures of HRQOL and fatigue might decline during the intervention. Therefore, the study addressed three primary aims. The first was to assess the changes in perceived QOL and fatigue preintervention and postintervention reported by the group of child participants and the parent group. The second aim was to determine the agreement between parent and child groups on HRQOL and fatigue, and the final aim was to examine percent change and amount of change in individual scores of each child and parent proxy for minimal clinically important differences (MCID) postintervention. Results were compared to published norms for children with CP and healthy children.4,6,16

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Six ambulatory children with spastic CP (2 girls, 4 boys) were recruited through the neurorehabilitation clinics at the local University Hospital and from community referrals.21,22 Their age range was 6 to14 years. Four children had the diagnosis of hemiplegia and 2 children had the diagnosis of asymmetrical spastic diplegia. Inclusion criteria were: (1) the ability to ambulate independently without an assistive device, and rated as level I on the GMFCS and (2) the ability to follow verbal directions for standardized testing. Exclusion criteria were: (1) orthopedic surgery or neurosurgery in the past 12 months, and (2) antispasticity medications orally or by injection in the past 6 months. Table 1 provides a summary of the demographic information for all 6 participants. The subjects were not receiving any other interventions. This study was part of a larger research project, and approval for the study was obtained from the University Institutional Review Board. Written informed consent was obtained from the parent(s) of each participant, and informed assent was obtained from the children.

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The Pediatric Quality of Life Inventory™ (PedsQL).

The PedsQL 4.0 Generic Core Scale includes parallel child self-report and parent-proxy report formats to measure HRQOL in both healthy and patient pediatric populations.5,14,16 It has been found to be a reliable and valid tool for children aged 2 to 18 years in studies with 1000 children and parents.25,26 In addition, it was found to be sensitive to age, acute versus chronic disability, and healthy children versus those with disability14 and more recently by GMFCS functional levels.5 Four separate dimensions are assessed with the PedsQL core scale: Physical Functioning, Emotional Functioning, Social functioning, and School functioning. The Physical Functioning score is used as the Physical Health Summary score, and the latter 3 dimensions can be combined to create the Psychosocial Health Summary score. The PedsQL Generic Core Scale was selected for this study so that results could be compared with published norms and with results from healthy children. The subjects also completed the PedsQL module for CP which was under development at the time.

The PedsQL Multidimensional Fatigue Scale is a module that follows the same self-report and parent-proxy report format. This scale includes 3 dimensions (general fatigue, sleep/rest fatigue, cognitive fatigue) and a total score. For both the Generic Core Scale and the Multidimensional Fatigue Scale, a 3 point (0, 2, 4) Likert scale is used for the young child category with responses ranging from 0 (never) to 4 (almost always) and a 5-point scale (0, 1, 2, 3, 4) is used for the other 2 age categories. Items are reversed scored and linearly transformed to a 0 to 100 scale for analyses, with higher scores indicating better HRQOL or fewer problems or symptoms (less fatigue). Both the Generic Core Scale and the Multidimensional Fatigue Scale have been used in a variety of studies with children with physical disabilities, including CP.2,3,5,12

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Pretraining and Posttraining Clinical Assessments.

Children were assessed on the child and parent forms of the PedsQL, and the Multidisciplinary Fatigue Scale one time each in the 2-week period before and after the training. Three different age versions were used: young children (5–7 years), children (8–12 years), and teen (13–18 years).

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BWSTT Apparatus and Protocol.

The protocol is described in more detail in the original article by Provost et al.22 The participants were supported in an appropriately fitted harness suspended from a hydraulic-weight supported system (LiteGait I system with BiSym attachment); ( and positioned over a motor-driven treadmill with variable speed control.

Treadmill training protocol included 12 sessions scheduled twice daily (morning and afternoon sessions) 6 days a week for 2 weeks. During each session, children walked on the treadmill for 30 minutes (usually three 10-minute walking sessions interspersed with 5-minute rest periods). A physical therapist and 2 research assistants facilitated the children's gait patterns during initial treadmill training sessions, with less assistance provided as the child progressed over the 2-week training period.

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Data Analysis

To assess group differences, the child and parent-proxy reports preintervention and postintervention were summarized by calculating group means and standard deviations for the total scores, the Physical and Psychosocial Health Summary scores and the Multidimensional Fatigue Scale subscales. Nonparametric statistics (Wilcoxon signed-rank tests) were used to compare pregroup and postgroup summary scores for the PedsQL and the Multidimensional Fatigue Scale. Published normative data for children with and without CP, where available, are included for comparisons.4,6,16

Agreement between child self-report and parent-proxy report for PedsQL Total, Physical and Psychosocial Health Summary, and Multidisciplinary Fatigue Scale scores were further quantified through Intraclass Correlation Coefficients (ICC 3, 1). According to Portney and Watkins27 values above 0.75 are indicative of good reliability and below 0.75 represent poor to moderate reliability.

In addition to group analyses, changes in individual children and parent scores were analyzed in 2 ways: (1) by computing the percent change pretest to posttest for the PedsQL Total and Health Summary Scores as well as totals and subscales of the Multidimensional Fatigue Scale, and (2) calculating changes in scores on child and parent measures preintervention to postintervention to determine if MCID were present on the PedsQL based on recent work of Varni et al.28 The MCID is the smallest difference in a score that patients perceive to be beneficial. These authors report significant MCID are present with a change of 4.36 points on Child Total score; 6.66 points on the Child Physical Health Summary; 5.30 points on the Child Psychosocial Health Summary; 4.5 points on the Parent Total score; 6.92 points on the Parent Physical Health Summary; and 5.49 points on the Parent Psychosocial Health Summary.28 MCID values for the Multidimensional Fatigue Scale total and subscale scores are not available.

Varni et al28 also defined a cutoff score on the PedsQL as one standard deviation below the mean of the total population sample (over 10,000 children in California; less than 10% with a chronic health condition such as, asthma or diabetes) indicating an “at-risk” status for impaired HRQOL (Child total score: 69.71; Child Physical Health Summary score: 72.98; Child Psychosocial Health Summary score: 66.03. Parent total score: 65.42; Parent Physical Health Summary score: 63.28; Parent Psychosocial Health Summary score: 64.38). All statistical analyses were conducted using SPSS 14.0 (SPSS, Chicago, IL).

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Six children completed the study. One parent did not turn in any forms and one child/parent set did not turn in the postforms, resulting in n = 6 children and n = 5 parents preintervention and n = 5 children and n = 4 parents postintervention.

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Child and Parent Group Comparisons for PedsQL and Fatigue

Tables 2 and 3 summarize the results of the child and parent PedsQL and Multidimensional Fatigue scales completed preintervention and postintervention for the 4 children with complete data. There were no significant changes in the prescores to postscores on either the PedsQL or the Multidimensional Fatigue Scale.

For the PedsQL, all postscores were higher than the prescores. The child and parent postscores were equal to or above the norms for a comparable group of children with CP and below norms for healthy children (see Table 2).

For the Multidimensional Fatigue scale, of the 8 scores (4 for children and 4 for parents) 5 increased from prescores to postscores, 2 decreased, and 1 remained the same. All scores preintervention and postintervention were below the norms for healthy children except the Sleep/Rest scores for the children, which were higher than the norms (75.00) both preintervention (82.29) and postintervention (78.13) (See Table 3).

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Agreement Between Child and Parent PedsQL and Multidimensional Fatigue Scale Scores

Agreement between Child and Parent PedsQL Generic Core Scale Total and Health Summary scores preintervention and postintervention is reported in Table 4. Parent/child ICC coefficients are in bold on the diagonal with all scores below a 0.75 indicating a poor to moderate relationship. The Child Pre and Post Total Scores demonstrated high agreement (above 0.75) with all Summary scores with the lowest score between the Total Pre and the Physical Summary score (0.76). Parent Pre and Post Total scores relationship to Psychosocial Summary scores were above the 0.75 cutoff as was the Total Prescore to the Physical summary score. However, the other relationships for the parent scores were low or negative which indicates illogical scores perhaps due to the small sample size.

ICC scores for the Multidimensional Fatigue Scale are in Table 5. The child/parent ICC coefficients are in bold on the diagonal with all above 0.75 except the Sleep/Rest subscale. All Child and Parent Total Prescores to subscale prescores are above 0.75 as are all post Total scores to subscale postscores.

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Individual Child or Parent Scores for QOL and Fatigue

Scores from the individual children and their parents for the PedsQL and the Multidimensional Fatigue Scale preintervention and postintervention as well as percent change scores are reported in Tables 6 and 7.

Four of 5 children had positive improvements on the PedsQL Total Score and the Psychosocial Health Summary Score based on MCID, whereas only child number 3 scored above the MCID for the Child Physical Health Summary score. These changes ranged from a low of 7.7% improvement for child number 1 on total QOL, to a high of 29.7% improvement for child number 3 on the Physical summary score. All four Parent Total and Physical Health Summary scores reflected changes greater than the MCID, whereas only 2 Parent Psychosocial Health Summary score changes were greater than the MCID. The majority of the percent changes reported by parents were larger than the changes reported by the children with 5 of 10 MDIC increasing by 30% or more. In addition, the parent of child number 2 initially scored the maximum of 100 on the QOL and fatigue scales and at follow-up indicated lower scores with a negative MCID for the QOL.

Two children's (3 and 6) Total and Health Summary scores put them below the cutoff for “at risk” for impaired HRQOL preintervention. Postintervention, they remained below the cutoff score except child 3's Psychosocial Health Summary score that moved above the cutoff score. Four of 5 children were “at risk” on the total parent-proxy report preintervention, 2 due to Psychosocial Health Summary, and 3 due to Physical Health Summary scores (1 was both). Only child 3 remained below the cutoff for Total score and Physical Health Summary score postintervention, although child 6 remained below on the Psychosocial Health Summary score (see Tables 6 and 7).

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Contrary to what was expected the 2-week intervention of intensive BWSTT resulted in positive changes in the HRQOL perceptions of the children receiving therapy. A interesting point is that while the children demonstrated positive gait changes22 the increase in the Total QOL score is due to an 11-point increase in the average Psychosocial Health Summary score compared with less than 5-point increase in the average Physical Health Summary score. This seems to indicate that their perception of the intervention affected their Emotional, Social, and School Functioning areas more than their Physical Functioning. These changes in Psychosocial Health are similar to those reported by Meuleners and Lee29 who noted that increases in HRQOL in adolescents over time are related to opportunities, and perception of health and control. Thus, these results may indicate that by providing children with CP with an intervention that is physically and psychologically challenging, with ongoing reinforcement of practitioners and parents, they experience an increase in their perception of health and control and consequently an increase in their QOL. This finding is important since the social and psychological impact of the disability has often been shown to be of greater importance to the individual than the physical aspects alone.30

The parents also reported positive changes postintervention with a greater average change in Total QOL scores than the children. However, this change was due to a very large (23 point) increase in the Physical Summary score and a less than 5-point change in the Psychosocial Summary score. This difference suggests an increased awareness of the children's abilities, with a greater focus on physical changes noted by the parents. This difference in emphasis was also noted in the individual changes in the MCID for the total HRQOL scores, which for the children was due primarily to large changes in the psychosocial domain, and for the parents was due to large changes in the physical domain. Similar findings have been reported by Cremeens et al31 investigating parent-proxy reports for healthy children 5.5 to 8.5 years of age. In their study, parents' mean scores of their children's physical HRQOL were higher than psychosocial HRQOL. In contrast, parent-proxy reports for children with CP as reported by Varni et al5 showed higher ratings for children's psychosocial HRQOL than the physical functioning HRQOL ratings.

Both child and parent groups average scores were similar or above the scores of other subjects with hemiplegic CP (GMFCS level 1) and their parents before the intervention.5 After the short intensive 2-week intervention both groups were above the average scores in all categories, suggesting a change in their perceptions in a short period of time. Despite the large changes in PedsQL measures, it should be noted that both children and parent groups continued to rate HRQOL well below the average scores for healthy children. These low scores are consistent with other researchers16 reporting significant HRQOL impairments in children with CP, not only in physical functioning, but even more profoundly, in their perception of their psychosocial functioning.

Overall, while demonstrating poor to moderate agreement as measured with the ICC, the parent/child coefficients were higher for postscores than for prescores on the PedsQL. The children's prescores to postscores were all very high, whereas the parents were low. These low or negative scores for the parent group maybe due to the negative change in scores of subject number 2 whose parent initially scored her daughter with a 100 across the board and then apparently became more aware of the child's ability during the course of the study and decreased her scores. Interestingly, the highest child/parent relationship in our study was in postintervention Psychosocial Health Summary scores (0.64) that is opposite from the highest scores in the Physical Health Summary relationship reported in a group by Varni et al.16 However, 0.64 is still a low score indicating the parents are not sensitive to their children's own perception of their status. Varni et al interpreted the poor relationship as representing a significant “hidden morbidity” where the parents appear to be unaware of the children's perceptions particularly their psychosocial status.

Change in Child and Parent Multidimensional Fatigue Scale scores reflect an improvement for the children (less fatigue) whereas the parent's scores generally declined indicating an increase in fatigue. Although the participants were physically tired, this fatigue was not a factor in decreasing their HRQOL, which in fact improved.

The 2 children who remained below the cutoff scores indicating an “at-risk” status for impaired HRQOL were also ranked this way by their parents. These 2 were the youngest children in the group and required encouragement to continue with the study. These low scores might indicate that an intensive therapy is not appropriate for young children.

The poor relationship between the parent's and child's Generic Core scores indicates that the parent's proxy cannot be substituted for the child's scores. The children's focus primarily on the psychosocial domain and the parent's focus on the physical domain imply that both perspectives should be included in the overall evaluation of the impact of intervention on the child and family.

Because of the nature of this pilot study, several limitations are present. A major limitation is the small sample size, although the obtained scores are similar to the published norms for children with hemiplegic CP indicating these subjects are representative of this population. Studies with greater power are needed to generalize results. In addition, a control group exposed to similar environmental influences (including individualized attention) in the 2-week period would provide support that changes truly reflect the impact of BWSTT intervention. Future studies should identify factors that affect parent's and children's scores and must track HRQOL changes over 3 to 6 months postintervention to support the stability of HRQOL changes in the participants.

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Therapists must always consider the impact of an intervention on the health, well-being, and QOL of the client. Even if an intervention improves physical status it may not be appropriate if it causes negative changes in the health and well-being of the individual. The positive preliminary findings of this study, even with a small sample size, suggest that an intensive intervention of therapy, in this case BWSTT, can improve the perceived HRQOL by the participants and by their parents.

In this pilot study, parent proxy and child reports provided valuable but different information. On the basis of these differences, reporting by both groups is recommended. Further study with children with CP and the relationship of HRQOL in conjunction with clinical studies is recommended to determine if therapeutic interventions not only improve physical status, but also long-term HRQOL.

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adolescent; body weight; cerebral palsy/physiopathology; cerebral palsy/rehabilitation; child; comparative study; health quality assessment; human movement system; exercise therapy/methods; gait/physiology; parents; quality of life; treatment outcome

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