The Relationship Between Gross Motor Function,Manual Ability, and Cognitive Function With Quality of Life in Children with Cerebral Palsy

Background:Cerebral palsy (CP) is the most common type of permanent movement and posturedisorder in childrenleading to contractures, deformities, and activity limitations. Quality of life is considered as an outcome variable to evaluate the effectiveness of interventions for children with CP. Therefore, we aimed to examine the relationship between quality of life and gross motor function,manual ability, and cognitivefunction inchildren with CP. Methods:200children with CP aged 4-12 years participated in this study through convenient sampling. Then, their quality of life, gross motor ability, hand function, and cognitive level were assessed using Cerebral Palsy Quality of Life Questionnaire (CPQOL), Gross Motor Function Classication System scale, Manual abilities Classication System Scales and SPARCLE (Study of Participation of Children with Cerebral Palsy Living in Europe) scale, respectively. Results: The results demonstrated that only the functional domain of the CPQOL was signicantly correlated withthe manual ability and cognitive level in these children (P=0.001, P=0.001 respectively). Conclusions:A child with CP with poor performance has the potential to report a poorQOL. This needs more evidence for elaboration. Well-being includes the presence of positive emotions and moods, the absence of negative emotions, satisfaction with life, fulllment, and positive functioning. In our study, we use CPQOL questionnaire that evaluates well-being along with functioning and participation. Shelley and colleagues(12)investigated the QOL of children with CP based on CPQOL as well asits relationship with gross motor function.We used this questionnaire not only for gross motor function but for manual ability and cognitive function as well.We found thatnot only the relationship between QOL subscale of functioning and gross motor function was closed to a signicant level, this relationship was signicant forthe child's manual ability and cognitive level. This is a conrmation of previous studies, adding that regarding performance, not only gross motor performance but also the manual ability and cognitive level should be considered. In a study on children who were ambulated,Omuraand co-workers(27)founda signicant relationship between walking abilities and the physical subscale of CPQOL. They also reported that there wasa positive correlation between physical function, gait function, and a child's level of communication with physical subscales of QOL. However, this study was performed on children who were able to walk.


Introduction
Cerebral palsy (CP) is one of the most common movements and postural disorders in childhood that occurs because of a lesion in the developing brain(1).
These children may experience a wide range of movement, postural, coordination, sensory, and cognitive disorders throughout their lives (2). Various treatment and rehabilitation interventions are performed to maximize the performance of these children (3,4). Many efforts have been made to investigate the effect of these interventions on children with CP byemploying appropriate outcome measures. In recent years, quality of life (QOL),as a manifestation of health and well-being, has been proposed as an outcome measure for evaluating the effectiveness of interventions (5). In the International Classi cation of Functioning (ICF), QOLhas been proposed as the ultimate goal of interventions(6). QOL can also be considered as a predictor of a child's health status (7).
According to the de nition of the World Health Organization, QOLis an individual's understanding of his or her situation and circumstances in life, which is based on their culture, value system, goals, expectations, standards, and priorities.Therefore, QOL is completely individualized and subjective and is based on people's understanding of different aspects of their lives(8, 9).Although QOL has a multidimensional structure, many researchers agree that it is equal to person's performance or ishighly dependent on their performance (10).Studies showed impairedQOL in children with CP. This degree of impairment is associated with the level of independence in daily activities, mobility, clinical limitations, and social interactions (11). Shelley and colleagues (12)examined the relationship between the QOL of children with CP and their level of performance. In their study, the CPQOL questionnaire was used to evaluate the QOL of children with CP, and Gross Motor Function Classi cation System (GMFCS) was used to evaluate their level of gross motor function.A signi cant relationship was found between the subscales of the QOL and gross motor function. However, this association was more related to thephysical subscalethan the psychosocial subscales.The relationship between performance and QOL is not limited to walking performance and a positive relationship between physical activity and QOL has also been reported (11).
Park and co-workers (13)usedpath analysisto assess the relationship betweenstrength, spasticity, gross motor function, and QOL on 62 children with spastic CP. There wasa signi cant and direct relationship between spasticity, strength, and gross motor function, and between gross motor function and health-related QOL, as well asbetween strength and children's QOL. In another study, Kolmanand colleagues(7) examined the predictors of health and QOL. They foundthat factors related to comfort, emotions, communication, and social interactions predicted QOL more than mobility and self-care. Maher and co-workers(14)also reported that physical activity signi cantly predicted the quality of physical and social life. However, in a systematic review of studies on the QOL of children and adolescents with CP in the middle-and low-income countries, it was reported that the physical subscale of QOL of children with CP washighly affected, and this physical subscale wasstrongly correlated with motor function (15). However, these children have a high QOL in the psychosocial subscale even if they have low performance (12).
It seems that gross motor function and manual and cognitive ability could predict the QOL of children with CP. Therefore, we aimed to investigate the relationship between performance of children with CP in terms of gross motor function, manual ability, and cognitive function with theirQOL.

Methods
In thiscross-sectional studywith non-probability sampling, 200 children with CP were enrolled fromeight rehabilitation centers and three schools for children with physical disabilities. We included children aged 4-12 years diagnosed with CP according to their medical records or their therapists' report, whose parents were literate andagreed with their participation. Children were classi ed topographically and physiologically according to the Surveillance of Cerebral Palsy in Europe (SCPE)(16).

Tools and Measures
The data for this study were collected using asocio-demographic characteristics questionnaire,the Persian version of the CPQOL-parent, GMFCS,Manual Ability Classi cation System (MACS), and the SPARCLE cognitive level estimation form.
The socio-demographic questionnaire includes 46 questions divided intofour sections: questions related to the child, the parents, the child's caregiver, and the child's health status.
The CPQOL-parent versionmeasures condition-speci c QOL and is completed by the parents.This questionnairehas 66 items and is appropriate to assess the QOL of children with CP aged 4-12 years.The answer to each question is divided into a 9-pointLikertscale, which the parent either selectsor draws a line around (17,18).CPQOL has sevensubscales, including(1) social well-being and acceptance; (2) functioning; (3) participation and physical health; (4) emotional wellbeing; (5) pain and impact of disability; (6) access to services; and (7) family health.The Persian version of the CPQOL-parent version questionnaire was validated according to the protocol provided by the developers (19), and had acceptable reliability (ICC=0.47-0.84) and the subscales had appropriate internal consistency (α=0.61-0.87) (19).
Gross motor function was assessed according to the GFMCS and based on spontaneous gross movement such as the child's head control, sitting, standing, and transferring (20). In this system, the gross motor function of children with CP is classi ed into ve levels. In level one, children have the most, and in level ve, children have the least independent motor function. This scale has acceptable validity and reliability (20,21).
The MACS assesseschildren's manual ability based on how their hands are used to control objects in everyday life (22). This system is de ned in ve levels similar to the GFMCS. Children in level one have the highest manual ability function, and children in Level ve have the least control over the objects. MACS has been validated in Persian and has an acceptable level of validity and reliability (23).
Cognitive function in children with CP was estimated and classi ed into three levels including: >70, 70-50, <50. This classi cation was prepared and used by SPARCLEin Europe (24). Parents with children with CP are asked to answer four questions. Then, based on their responses, the children's cognitive level is identi ed.

Procedures
Following the recruitment of the participants, the aims and steps of completing the questionnaireswere explained to them. Then, upon their willingness,written consent was obtainedfrom the parents. In the next steps, the questionnaires of the study were completed according to the following order. First, CPQOL and socio-demographicquestionnaireswere completed consecutively by the parents. Then, the children's GFMCS, MACS, and level of cognition were identi ed by an assessor (three occupational therapists) by interviewing the parents. On average, the whole process took about 60 minutes. This study was approved by the Ethical Committee of the University of Social Welfare and Rehabilitation Sciences(ID: 801/4/88/58).

Data analysis
Data were analyzed using SPSS software, version 19. Descriptive statistics were used to determine the characteristics of the participants. Linear regression was used to investigate the relationship between the subscalesof CPQOL and children's functions, including gross motor function, manual ability, and cognitive function.

Results
The mean ± SD age of the 200 children participating in this study was 7.7 ± 2.40years. The distribution of various levels of manual ability function was almost close to each other in ve levels according to MACS. Levels four and three hadthe highest percentage with 23% and 20%, respectively, and the other levels were 19% each. The distribution of gross motor function according to the GFMCS was different fromMACS. Levels four and two were the highest with 30.5%, and 24.5% respectively. The lowest percentage was at level one with 11% (Table 1). Using linear regression, therelationship between CPQOL subscales and gross motor function did not show a statistically signi cant difference in any of the subscales.However, this relationship with the functioning subscale was close to a signi cant level (P = 0.071) ( Table 2). Because of the similarity of the scale of variables with respect to non-standardized coe cients B, the most effective relationships were obtained with the subscales of functioning and participation and physical health. Negative relationships indicate an inverse relationship between severity of disability and QOL. The results of linear regression regardingthe relationship between the CPQOLsubscales and the children's manual ability were not statistically signi cant except for the functioningsubscale (P < 0.001) ( Table 2).
The relationship between CPQOL subscales and the children's cognitive level showed a statistically signi cant relationship only with the functioning subscale (P < 0.05) ( Table 2). The relationship with other subscales was not statistically signi cant.

Discussions
In this study, the relationship between CPQOLsubscales and children with CP's functions (gross motor function, manual ability, and cognitive level) were investigated.The main question of this study was: do children with a high level of function (i.e., gross motor, manual ability, and cognitive level) have a higher quality of life?According to the result of this study, the relationship between CPQOL subscales and gross motor function did not show a statistically signi cant in any of the subscales. Also,the relationship between the CPQOLsubscales and the children's manual ability wasnot statistically signi cant except for the functioningsubscale.The relationship between CPQOL subscales and the children's cognitive level showed a statistically signi cant relationship only with the functioning subscale.
In previous studies, it has been concluded that despite the relationship between performance and physical subscales ofQOL, there is no relationship between performance and psychosocial subscales ofQOLor this relationship is weak. It should be noted that in these studies, questionnaires used assessed the activities that the child can do more than the general well-being of children. In other words, they weremore related to performance than well-being (25,26). Wellbeing is a broader term than performance and is a more appropriate term to describe health. Well-being includes the presence of positive emotions and moods, the absence of negative emotions, satisfaction with life, ful llment, and positive functioning. In our study, we use CPQOL questionnaire that evaluates well-being along with functioning and participation. Shelley and colleagues (12)investigated the QOL of children with CP based on CPQOL as well asits relationship with gross motor function.We used this questionnaire not only for gross motor function but for manual ability and cognitive function as well.We found thatnot only the relationship between QOL subscale of functioning and gross motor function was closed to a signi cant level, but this relationship was also signi cant forthe child's manual ability and cognitive level. This is a con rmation of previous studies, adding that regarding performance, not only gross motor performance but also the manual ability and cognitive level should be considered. In a study on children who were ambulated,Omuraand coworkers (27)founda signi cant relationship between walking abilities and the physical subscale of CPQOL. They also reported that there wasa positive correlation between physical function, gait function, and a child's level of communication with physical subscales of QOL. However, this study was performed on children who were able to walk.
Delicate motor function, including speed and mastery of the upper limbs and visual-motor control, were named as the most important motor factors affecting the QOLof children with CP in a study by Chen and colleagues(28).In Kolman and co-workers' study (7), inability to walk or understand the caregiver, being unhappy or sad, and not going to school were signi cant predictors of their poor QOL in children with CP.
The results of this study also demonstrated a signi cant relationship between the functioning aspects of CPQOL and children's manual ability. The results of this study are different from Shelly and colleagues' (12) that showed a signi cant relationship between all CPQOL subscales (except "access to health services" subscale). In their study, the relationship between the physical subscales of CPQOL was stronger than the psychosocial one.Teuscherco-workers(2019)reported that manual ability and QOLwere associated with health in a ve-year follow-up studyof children with CP. However, despite the signi cant relationship between children's function and physical subscale of QOL, this relationship was not signi cant with other subscales(29). Itmaybe concluded that a child with CP with poor performance has the potential to report a high QOL. What has been mentioned in studies as a reason for this is that the person with CP has the ability to adapt to the conditions of disability. This needs more evidence for elaboration.

Limitations
Due to the lack of a proper registry system for recording information on children with CP, access to these children through randomization was not possible.
Therefore, this study applied the convenient sampling procedure. One of the strengths of our study was our large sample size with appropriate distribution in various levels of gross motor function and manual ability. Availability of data and materials

Declarations
The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.

Competing interests
The authors have no con icts of interest.

Funding
This study was supported by grant in University of Social Welfare & Rehabilitation Science.

Authors' contributions
Mehdi Rassa ani (carried out the design and coordinated the study, participated in most of the experiments and prepared the manuscript) Zahra Nobakht (provided assistance for all experiments and prepared the manuscript).
FarinSoleimani (carried out the design and coordinated the study, participated in most of the experiments and prepared the manuscript).
RoshanakVameghi (provide assistance in the design of the study, coordinated and carried out all the experiments and participated in manuscript preparation)