Reliability and Clinical Significance of the Pediatric Balance Scale (PBS) in the Greek Language in Children Aged 4 to 18 Years

Introduction: In recent years, many tests have been developed to assess the mobility and functional capacity of children with motor dysfunctions. The Pediatric Balance Scale (PBS) is a qualitative assessment test of the motor behavior of children aged 4 to 18 years. Purpose: The purpose of the proposed research is to determine the external reliability of the test Pediatric Balance Scale translated for the first time in Greek in children aged 4 to 18 years, in order to have a reliable tool in the hands of experts. Method: 26 children (14 girls and 12 boys with an average age of ±10,673 years of age) participated in this research. The Greek adaptation of the PBS and a Nikon 5300 digital camera for video recording were used for data collection. Results: The results found that there were no statistically significant differences between the two independent evaluators and that the Pediatric Balance Scale test had strong reliability. Overall, the results of the present investigation provided considerable evidence suggesting that the Greek adaptation of the PBS test has good inter-rater reliability and can be used to detect kinetic disorders in children aged 4 to 18 years for the Greek population.


Introduction
Stability and balance are primary characteristics of the human body, which are controlled and determined by various factors. Anatomically individual stands against gravity through a bone system. But muscles also have a significant share in achieving and maintaining balance and posture through kinetic standards [1].
All human activities require control, stability and balance. Primary motor skills, such as walking, standing and seating, depend on the ability of posture control [2] [3] [4] [5].
The balance is defined as the ability to control the centre of gravity of the body mass relative to the base of support. The balance depends on: the body support base, the position of the center of gravity and the line of gravity. In the context of the International Classification of Functioning, Disability and Health (International Classification of Functioning, Disability and Health), which was created by the World Health Organization, balance is described as both structure/function and activity. Balance is an important functional ability that significantly affects man's ability to perform daily activities for his survival such as: maintaining a stable posture, steadily moving from one position to another, maintaining upright posture, and much more [6].
When performing physiological activities in daily life, the person displays two types of balance, static and dynamic. It is important for normal development the static developed before dynamic balance in order to perform motor skills [7]. For the proper practice of balance, as already known, there is a low correlation between dynamic and static balance, which is why they should be detected and practiced separately [8]. Balance is one of the most basic motor abilities the child develops. For the purposes of this study, functional balance in children was defined as the ability to maintain the body mass weight center in relation to the support base in typical children's activities of daily life, school activities and outdoor playing.
Cerebral Palsy (CP) is a group of permanent cerebral disorders, which are attributed to lesions or abnormal cerebral development during prenatal or perinatal stage. Symptoms include poor motor control, muscle stiffness and in some cases, skeletal deformations which lead to poor balance [3] [9].
The Pediatric Balance Scale is a modified version of the Berg Balance Scale that is used to assess functional balance skills in school-aged children, from typically developing children and children with motor impairments. The scale consists of 14 items that are scored from 0 points (lowest function) to 4 points (highest function) with a maximum score of 56 points [10].
Its purpose is to assess the functional balance and motor disorders of school-age children with mild to moderate motor dysfunctions in the context of daily tasks. PBS also has the ability to distinguish normal children with those with mild motor damage, as well as those with moderate to severe motor impairment. Several studies on the reliability and validity of the test have been published [9] [11] [12].
Franjoine, Gunther and Taylor (2003) [9] suggested that PBS is reliable when Open Journal of Preventive Medicine used in school-age children with mild to moderate mobility problems. Jin-Gang Her, Ji-Hea Woo and Jooyeon, (2012) [13], demonstrated PBS high absolute reliability, so the test was considered a reliable tool for examining the functional balance of children with cerebral palsy. Snehal, Vijaymuniraj and Solomon (2011) [14], also concluded that the PBS is a valid scale and therefore suggested PBS in clinical studies to assess balance in children. Ries

Participants
Participants consisted of 26 children (14 girls and 12 boys with an average age of ± 10,673 years). The participants had been previously diagnosed with neurological disorders (cerebral palsy, Down syndrome) by a neurologist or/and a child neurologist. The clinicians that were treating them suggested a PBS evaluation.
The participants were selected based on that they could follow the instructions, they had no other complications that could interfere with the procedure (range of motion of the hips, knees, ankle joints and shoulder flexion etc). All the participants were receiving physical therapy, functional level (mild and moderate)

Assessment Tool
Data were obtained with the use of the following instruments:

Data Analysis
To examine the reliability of the PBS translated into Greek, inter-rater reliability scores were computed via intra-class correlation coefficients (ICC), using  [18].
The Spearman correlation coefficient, which is a non-parametric statistical measure, was also used to find the statistical dependence between two variables

Results
The results show that there is excellent reliability in all classes of the instrument for all age levels of the sample. For pilot reliability measurements, reliability scores ( Table 2) were acceptable to excellent agreement for all subscales. As for the main study of the Greek adaptation of the PBS (Table 3, Table 4), results showed excellent agreement for all subscales and sample.
Tables 2-4, showed excellent agreement for all PBS subscales and sample ages.
As for the pilot testing of the Greek version of the PBS, results ( Table 2) showed excellent agreement. In particular, the ICC factors for the overall scores are in total greater than 0.992. As for the main study of the Greek version of the PBS (Table 3 and Table 4), results showed also excellent agreement for all subscales and sample ages.
For PBS test, Table 5 showed agreement from an acceptable 0.49 trial 3rd to excellent 0.867 trial 8th in the Kappa index, while the Spearman factor ranged from 0.773 to 1.00. As an outcome, for the PBS test the results indicate moderate to high reliability and the test can be used in the Greek population.

Discussion
This study has examined the determination of the external reliability of the Pediatric Balance Scale test translated for the first time in Greek in children aged 4 to 18 years, in order to have a reliable tool in the hands of the experts, both for evaluation the functional balance of school-age children with mild to moderate motor dysfunctions, as well as for the evaluation of motor disorders in the context of daily tasks. The data have indicated that there were no statistically significant differences between the two independent evaluators and that the Pediatric Balance Scale test had strong inter-rater reliability.
In particular, the results showed for the overall score strong PBS reliability  [19], which demonstrated that chivalry is a sustainable therapeutic strategy to improve the balance and functional performance of everyday skills life in children with mild to moderate balance problems.    [15], where the results showed great reliability in the overall PBS score (ICC = 0.85). As for the intra-observer agreement scores, results were excellent for both observers (ICC = 0.98) which was exceptional as well as those of Yi, Hwang, Kim, Kwon, (2012) [12], Duarte, Grecco, Franco, Zanon, Oliveira, [16] and Jantakat, Ramrit, Emasithi and Siritaratiwat, (2015) [17], where each research proved that PBS was a valid and reliable tool (p < 0.001).

Conclusions
Overall, the results of the present research provided considerable evidence suggesting that the Greek translation of PBS test is reliable and can be used to detect kinetic disorders in children aged 4 to 18 years in the Greek population. More research must be done with a bigger number of participants to investigate and determine the intra-inter reliability of the test.

Limitations
As to the sample: the sample was only from a small city of Trikala in Greece as the investigation was carried out there.