Original Article
A New Tool for Identifying Children With Motor Problems: Reliability and Validity Study
Journal of Child Neurology 2014, Vol. 29(5) 592-598 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0883073813513836 jcn.sagepub.com
Luba Zuk, PhD1, Hila Tlumek, MSc1,2, Michal Katz-Leurer, PhD1, Chava Peretz, PhD1, and Eli Carmeli, PhD1
Abstract This study examined reliability and validity of the Zuk Assessment for diagnosis of motor problems and determined standardized scores in an Israeli population aged 5 to 6 years. For standardization, 156 children recruited from 13 Kindergartens of typically developing children were evaluated with the Zuk Assessment. Intrarater and interrater reliability were examined on 2 samples of 15 and 13 children, respectively. A total of 151 children referred for motor problems were examined with the Zuk and Movement Assessment Battery for Children assessment tools for validation of the Zuk Assessment. Findings showed that the Zuk total score had a normal distribution similar to that found in the literature identifying 5.1% (–2 standard deviations) and 12% (between –1 and –2 standard deviations) of children with motor-related problems. Reliability was indicated by high intraclass correlation scores both in intrarater (intraclass correlation ¼ .89) and interrater (intraclass correlation ¼ .95) paradigms. The Zuk assessment identified differences in subgroups, namely, typical, suspicious, and impaired, as found in the Movement Assessment Battery for Children, confirming the Zuk validity. Keywords standardization, tool, reliability, validity, motor problems Received August 13, 2013. Received revised October 3, 2013. Accepted for publication October 28, 2013.
Motor problems are often described as performance with poor motor coordination that influences the everyday practical tasks that the child has to perform, and this, in spite of the fact that the measure of intelligence is normal and age-equivalent (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition).1 In his work on disorders of motor development, Sigmundsson2 stated that motor competence not only allows children to carry out tasks such as dressing, feeding, and bathing (activities of daily living) but it also affects their selfesteem and how they are viewed in the presence of their peer group. His research has shown that 6% to 10% of children will have problems with motor competence and will fall into a range below the norm. If motor problems and clumsiness are identified in preschool children and they do not result from major motor problems such as cerebral palsy or mental retardation, this could be a sign of a risk factor for academic performance in school. Therefore, it is important to identify and assess these motor problems early, even before these children enter into the first grade, in order to intervene effectively with the motor aspect of development and its impact on function.3 The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, defined Developmental Coordination Disorder1 as difficulty in performing movement skills for daily activities where motor coordination in the natural environment is
required.4 Participation in typical childhood activities is part of normal, healthy living. Consequently, Developmental Coordination Disorder restricts participation in the peer group potentially rendering the child a social outcast.5 Longitudinal studies show that the chronic aspect of this disorder has farreaching effects on academic, social, emotional, and behavioral function.6 The assessment tools most commonly used for identifying children with Developmental Coordination Disorder are the Assessment Battery for Children7 and the BruininksOseretsky test of motor proficiency.8,9 As noted before that cultural differences have an effect on motor development,10 the diverse population in Israel with its many cultural differences might not always be compatible with
1
Department of Physical Therapy, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 2 Child Development Center, Physical Therapy Department, Rivke Ziv Hospital, Zfat, Israel Corresponding Author: Luba Zuk, PhD, Sackler Faculty of Medicine, Stanley Steyer School of Health Professions, Department of Physical Therapy, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel. Email: [email protected]
Zuk et al these tools. Children from a specific culture might be exposed to activities differently, for example, ball games, which are an integral part of the Movement Assessment Battery for Children test. A tool for identification of the performance quality of motor problems in the preschool and first grades at school, suitable for the needs of an Israeli population would be beneficial for screening and assessing motor competence and function. As a result, timely intervention for existing motor problems could help reduce some of the future secondary problems that might arise. The Zuk Assessment (Zuk), which examines underlying components of motor function necessary for skills used in daily activities, evolved for this population. The Zuk has been used by therapists in Israel for more than 5 years.11,12 Before being widely used in Israel, it underwent examination of its reliability13 and subsequently the validity was tested.14,15 The purpose of this study is to examine reliability and validity of the Zuk Assessment for identification and diagnosis of motor problems and determine its standardized scores in an Israeli population aged 5 to 6 years.
Methods Participants The first step of the study was carried out in order to statistically represent the typically developing population of children in Israel. We used the approach of a hierarchical sample with reference to the following variables: urban/nonurban (rural) and secular/religious, and in this framework the representation of the socioeconomic mix of the general population was achieved. In accordance with this, 156 children aged 5 to 6 years were recruited from the normal school system. Thirteen Kindergartens were chosen to represent different social backgrounds. Ten Kindergartens, 3 of which were located in urban centers (n ¼ 68) and 7 in rural communities (n ¼ 58), were of a secular background. Three of the remaining 13 Kindergartens were of religious educational background (n ¼ 30). In each of the 13 Kindergartens, all the children recruited were examined with the Zuk assessment in accordance with the directions specified in the manual. In total, 156 children aged 5 to 6 years were included in the study. In our study, the participant sample distribution of gender, domicile, and position in family, gestation, birth process, and walking age was similar to the Israeli general population.16 One hundred fifty-one children were included in the second step of the study. Inclusion criteria were children 5 to 6 years of age referred due to gross and/or fine motor problems and grapho-motor problems. Exclusion criteria included orthopedic problems, mental retardation, cerebral palsy, and congenital abnormalities. All children were referred to Child Development Centers and were examined with the Zuk and Movement Assessment Battery for Children assessment tools in order to validate the Zuk Assessment. In steps 1 and 2, the Tel Aviv University ethics committee, the Health Ministry, and the Ministry of Education in Israel approved the research project. Written informed consent was obtained from all parents.
Instrument The Zuk assessment tool is organized into 10 categories that include 38 subtest items (Table 1) and examines the underlying motor
593 Table 1. Categories and Subcategories of Scored Subtest Items. Category and subcategories 1. Standing
Walking
2. Balance reactions Static Dynamic
3. Changing posture
4. Head and shoulder control and strength 5. Sitting: Motor components Long sitting control
Trunk: Passive range of motion
Subtest items
Score range
Symmetry: Posture Symmetrical weight bearing Shoulder protraction Symmetry Heel-toe push-off Trunk rotation
0–1 0–1 0–1 0–1 0–1 0–1
Standing: Preferred leg Standing: Nonpreferred leg Hopping: 2 feet Hopping: Preferred leg Hopping: Non-preferred leg Sitting-standing-prone-standingsupine-sitting Distinguishes stomach from back Initiates movement from legs Falls or jumps into posture Pull to sit Cobra position Hamstring length
0–4 0–4 0–4 0–4 0–4 0–12
Symmetrical weight bearing Weight bearing on ischial tuberosity Back straight Knees extended Extension Side flexion Rotation
6. Graphic-motor function Draw 3 crosses Crosses midline Pressure on pen Smooth line Draw a line of crosses Moves page or body to complete line Fine motor function Picks up small beads 7. Blocks Builds a tower: 10–12 blocks Begins building with same hand as drawing the cross Trunk and arms cross Crosses from right to left Midline Crosses from left to right 8. Eyes: Focus and follow Follows object in all directions 9. Development: Preferred eye Preferred side Preferred hand 10. Joint hyperlaxity Upper and lower limbs Total score range
0–1 0–1 0–1 0–8 0–8 0–1 0–1 0–1 0–1 0–1 0–2 0–2 0–2 0–2 0–2 0–2 0–1 0–5 0–2 0–1 0–2 0–2 0–8 0–2 0–2 0–1 0–100
components in 3 areas of competence, gross motor, fine motor, and graphic motor function. The 10 categories were selected and developed for the assessment by a pediatric physical therapist who is a senior lecturer in pediatrics in the medical faculty at the Tel Aviv University (LZ). Content validity of the Zuk Assessment tool was examined by 3 expert pediatric physical therapists, all of whom had 15 to 20 years of experience in the field of assessment and treatment of children with motor problems. They validated the inclusion of all the subtest items. Table 1 shows the 10 categories and the subtest
594 items of the Zuk. It includes standing and walking (6 items); static balance (2 items) and dynamic balance (3 items); changing posture (4 items); head and shoulder control and strength (2 items); sitting (8 items); graphic motor development (4 items); fine motor development (5 items); ability of the eyes to focus and follow (1 item); preferred eye and hand development (2 items), and finally joint hyperlaxity (1 item). The scoring method is simple and easy to use. Scores are calculated according to the successful achievement of the subtest item being examined. The total score is the sum of the scores of the subtest items examined in the 10 categories. Table 1 presents the score of each subtest item in each category. According to the items examined, children can score between 0 and 1, 0 and 2, 0 and 4, and 0 and 8. Each category has a different total maximal score that varies between 1 and 20. Finally the total score shows the level of function and motor performance of the child being examined. The higher score represents better performance. In 8 of the 10 categories examined, subtest items have identical evaluation scores for performance for ages 4 to 8 years inclusive. However, in the category of static and dynamic balance and tower building, the scores are age related and noted accordingly. Therefore, all age groups examined reflect the scores of the assessment tool. The manual of the test gives precise instructions on how to present, execute, and score each of the subtest items. The length of time taken to score the subtest item is not taken into consideration. Three trials are given for execution of each subtest item and the 2 most similar (best or worst) results record the score. Subtest items are presented verbally with the understanding, on the part of the examiner, that the child grasps the meaning of the instructions; if this is not so, then an interpreter needs to be present (this with regard to the diverse population in Israel). No practice runs of the subtests are given. Scoring of the results reflects the automatic level of motor function of the child being examined. Administration of the test is userfriendly, takes 35 to 45 minutes to execute, and requires a minimum of equipment.
Procedure In both the first and second steps of the study, each child was examined individually in a quiet, private room that was similarly set up for the assessment. Each room contained a free walking space of at least 5 to 6 m for testing the walking and balance subtest items, and a small table and chair for fine and grapho-motor examination. All equipment used for both the Movement Assessment Battery for Children and the Zuk Assessment was easily accessible to the examiner.
Reliability Step 1 of the study: In the population sample of 156 typically developing children, 28 (*20%) were randomly selected from the sample in order to undergo repeated measures. Intrarater reliability: From this group of 28 children, 15 children were randomly selected and examined and assessed at 2 different points in time (10-14 days’ interval) by 1 of the authors to record the intrarater reliability.13 Interrater reliability agreement was examined between one of the authors13 and a second physical therapist who was experienced in the use of the Zuk Assessment, on the remaining 13 of the 28 randomly chosen children simultaneously observing and noting their findings.
Journal of Child Neurology 29(5)
Validity To ensure that the subtest items represented all aspects of motor function included in the tool, the face and content validity were examined by 3 pediatric physical therapists with 15 to 20 years of experience and who were skilled in the use of motor assessments. Construct validity was assessed by examining the distribution of the scores in the total sample with the assumption that 5% to 10% would be identified with motor problems, and that a larger number of males would be identified. In the second step of the study, 151 children with suspected gross and/or fine motor problems who had been referred to child development centers, were examined with the Zuk and Movement Assessment Battery for Children assessment tools for validation of the Zuk Assessment. Each child was assessed with both the tools, 1 week apart in time and with a random choice of initial assessment (Movement Assessment Battery for Children or Zuk).
Statistical Analysis Normal distribution of the scores in the categories and the total score were evaluated with the Kolmogorov-Smirnov test (step 1). The t test was applied to compare scores between the subgroup of 13 and 15 participants that were chosen for intrarater and interrater reliability and the remaining group. Reliability for continuous scores was evaluated with intraclass correlation. For categorical variables, the Kappa and percentage agreement were used. Validation of the Zuk with the Movement Assessment Battery for Children: According to the cut-off of the Zuk Assessment, a 1-way analysis of variance model was applied to assess the differences in the Movement Assessment Battery for Children Assessment score; P .05 was considered statistically significant. All statistical analyses were performed using SPSS v. 17 software packages.
Results Step 1 Birth order was diverse in the sample, 145 children were born after a normal pregnancy and 11 after bed rest (mean gestational age [weeks] ¼ 39.63 + 2.00); 129 were born without any complications, 22 with caesarean intervention, 4 with vacuum birth, and 1 with forceps. Sixty-four children walked before 1 year of age. Mean age at entry into the study was 5.47 + .37 years. Gender was found to be split 78 boys and 78 girls. The ratio of boys to girls with motor problems was found to be 3:2. Joint hyperlaxity was present in 31 children. Subject score distribution in 10 categories and total score are presented in Table 2. Total score and category scores: The total average score was 79.5 (standard deviation ¼ 10) close to the median of 81 (Q1-Q3 ¼ 74-87). In the categories of standing/walking, changing posture, fine motor function, and preferred side, a ceiling effect could be seen as expected in a typically developing population.
Intrarater Reliability No difference in the total score was found between this group (n ¼ 15) and the remaining subjects (n ¼ 141; t test, P ¼ .2243). Results of the intrarater reliability included
Zuk et al
595
Table 2. Distribution of Subject Scores in 10 Categories and Total Score (n ¼ 156). Category 1. Stand/walk 2. Balance reaction 3. Posture change 4. Head and shoulders 5. Sitting 6. Fine motor 7. Blocks 8. Focus/Follow 9. Preferred side 10. Joint mobility Total score
Number items
Score range
M
Standard deviation
Median (P50)
Interquartile range (P25-P75)
6 5 4 2 8 5 4 1 2 1 38
0–6 0–20 0–15 0–16 0–11 0–12 0–7 0–8 0–4 0–1 0–100
5.4 14.1 14.6 12.3 7.1 10.6 4.9 6.3 3.4 0.8 79.5
0.8 4.8 1.0 3.9 1.6 1.5 1.4 2.4 1.0 0.4 10.0
6 15 15 12 7 11 5 8 4 1 81
5–6 11–18 15–15 8–16 6–8 10–12 4–6 6–8 2–4 1–1 74–87
Table 3. Reliability of Zuk Assessment by Intraclass Correlation Coefficients and Confidence Intervals. Intrarater reliability (n ¼ 15)
Interrater reliability (n ¼ 13)
Category
ICC
95% CI
P value
ICC
95% CI
P value
1. Stand/walk 2. Balance reaction 3. Posture change 4. Head and shoulders 5. Sitting 6. Fine motor 7. Blocks 8. Focus/follow 9. Preferred side 10. Joint mobility Final score
.42 .89 .20 .87 .28 .56 .27 .72 .42 .46 .89
0–.76 .71–.96 0–.63 .66–.96 0–.69 .12–.82 0–.69 .36–.89 0–.75 0–.78 .71–.96
.0596
A New Tool for Identifying Children With Motor Problems: Reliability and Validity Study
Journal of Child Neurology 2014, Vol. 29(5) 592-598 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0883073813513836 jcn.sagepub.com
Luba Zuk, PhD1, Hila Tlumek, MSc1,2, Michal Katz-Leurer, PhD1, Chava Peretz, PhD1, and Eli Carmeli, PhD1
Abstract This study examined reliability and validity of the Zuk Assessment for diagnosis of motor problems and determined standardized scores in an Israeli population aged 5 to 6 years. For standardization, 156 children recruited from 13 Kindergartens of typically developing children were evaluated with the Zuk Assessment. Intrarater and interrater reliability were examined on 2 samples of 15 and 13 children, respectively. A total of 151 children referred for motor problems were examined with the Zuk and Movement Assessment Battery for Children assessment tools for validation of the Zuk Assessment. Findings showed that the Zuk total score had a normal distribution similar to that found in the literature identifying 5.1% (–2 standard deviations) and 12% (between –1 and –2 standard deviations) of children with motor-related problems. Reliability was indicated by high intraclass correlation scores both in intrarater (intraclass correlation ¼ .89) and interrater (intraclass correlation ¼ .95) paradigms. The Zuk assessment identified differences in subgroups, namely, typical, suspicious, and impaired, as found in the Movement Assessment Battery for Children, confirming the Zuk validity. Keywords standardization, tool, reliability, validity, motor problems Received August 13, 2013. Received revised October 3, 2013. Accepted for publication October 28, 2013.
Motor problems are often described as performance with poor motor coordination that influences the everyday practical tasks that the child has to perform, and this, in spite of the fact that the measure of intelligence is normal and age-equivalent (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition).1 In his work on disorders of motor development, Sigmundsson2 stated that motor competence not only allows children to carry out tasks such as dressing, feeding, and bathing (activities of daily living) but it also affects their selfesteem and how they are viewed in the presence of their peer group. His research has shown that 6% to 10% of children will have problems with motor competence and will fall into a range below the norm. If motor problems and clumsiness are identified in preschool children and they do not result from major motor problems such as cerebral palsy or mental retardation, this could be a sign of a risk factor for academic performance in school. Therefore, it is important to identify and assess these motor problems early, even before these children enter into the first grade, in order to intervene effectively with the motor aspect of development and its impact on function.3 The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, defined Developmental Coordination Disorder1 as difficulty in performing movement skills for daily activities where motor coordination in the natural environment is
required.4 Participation in typical childhood activities is part of normal, healthy living. Consequently, Developmental Coordination Disorder restricts participation in the peer group potentially rendering the child a social outcast.5 Longitudinal studies show that the chronic aspect of this disorder has farreaching effects on academic, social, emotional, and behavioral function.6 The assessment tools most commonly used for identifying children with Developmental Coordination Disorder are the Assessment Battery for Children7 and the BruininksOseretsky test of motor proficiency.8,9 As noted before that cultural differences have an effect on motor development,10 the diverse population in Israel with its many cultural differences might not always be compatible with
1
Department of Physical Therapy, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 2 Child Development Center, Physical Therapy Department, Rivke Ziv Hospital, Zfat, Israel Corresponding Author: Luba Zuk, PhD, Sackler Faculty of Medicine, Stanley Steyer School of Health Professions, Department of Physical Therapy, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel. Email: [email protected]
Zuk et al these tools. Children from a specific culture might be exposed to activities differently, for example, ball games, which are an integral part of the Movement Assessment Battery for Children test. A tool for identification of the performance quality of motor problems in the preschool and first grades at school, suitable for the needs of an Israeli population would be beneficial for screening and assessing motor competence and function. As a result, timely intervention for existing motor problems could help reduce some of the future secondary problems that might arise. The Zuk Assessment (Zuk), which examines underlying components of motor function necessary for skills used in daily activities, evolved for this population. The Zuk has been used by therapists in Israel for more than 5 years.11,12 Before being widely used in Israel, it underwent examination of its reliability13 and subsequently the validity was tested.14,15 The purpose of this study is to examine reliability and validity of the Zuk Assessment for identification and diagnosis of motor problems and determine its standardized scores in an Israeli population aged 5 to 6 years.
Methods Participants The first step of the study was carried out in order to statistically represent the typically developing population of children in Israel. We used the approach of a hierarchical sample with reference to the following variables: urban/nonurban (rural) and secular/religious, and in this framework the representation of the socioeconomic mix of the general population was achieved. In accordance with this, 156 children aged 5 to 6 years were recruited from the normal school system. Thirteen Kindergartens were chosen to represent different social backgrounds. Ten Kindergartens, 3 of which were located in urban centers (n ¼ 68) and 7 in rural communities (n ¼ 58), were of a secular background. Three of the remaining 13 Kindergartens were of religious educational background (n ¼ 30). In each of the 13 Kindergartens, all the children recruited were examined with the Zuk assessment in accordance with the directions specified in the manual. In total, 156 children aged 5 to 6 years were included in the study. In our study, the participant sample distribution of gender, domicile, and position in family, gestation, birth process, and walking age was similar to the Israeli general population.16 One hundred fifty-one children were included in the second step of the study. Inclusion criteria were children 5 to 6 years of age referred due to gross and/or fine motor problems and grapho-motor problems. Exclusion criteria included orthopedic problems, mental retardation, cerebral palsy, and congenital abnormalities. All children were referred to Child Development Centers and were examined with the Zuk and Movement Assessment Battery for Children assessment tools in order to validate the Zuk Assessment. In steps 1 and 2, the Tel Aviv University ethics committee, the Health Ministry, and the Ministry of Education in Israel approved the research project. Written informed consent was obtained from all parents.
Instrument The Zuk assessment tool is organized into 10 categories that include 38 subtest items (Table 1) and examines the underlying motor
593 Table 1. Categories and Subcategories of Scored Subtest Items. Category and subcategories 1. Standing
Walking
2. Balance reactions Static Dynamic
3. Changing posture
4. Head and shoulder control and strength 5. Sitting: Motor components Long sitting control
Trunk: Passive range of motion
Subtest items
Score range
Symmetry: Posture Symmetrical weight bearing Shoulder protraction Symmetry Heel-toe push-off Trunk rotation
0–1 0–1 0–1 0–1 0–1 0–1
Standing: Preferred leg Standing: Nonpreferred leg Hopping: 2 feet Hopping: Preferred leg Hopping: Non-preferred leg Sitting-standing-prone-standingsupine-sitting Distinguishes stomach from back Initiates movement from legs Falls or jumps into posture Pull to sit Cobra position Hamstring length
0–4 0–4 0–4 0–4 0–4 0–12
Symmetrical weight bearing Weight bearing on ischial tuberosity Back straight Knees extended Extension Side flexion Rotation
6. Graphic-motor function Draw 3 crosses Crosses midline Pressure on pen Smooth line Draw a line of crosses Moves page or body to complete line Fine motor function Picks up small beads 7. Blocks Builds a tower: 10–12 blocks Begins building with same hand as drawing the cross Trunk and arms cross Crosses from right to left Midline Crosses from left to right 8. Eyes: Focus and follow Follows object in all directions 9. Development: Preferred eye Preferred side Preferred hand 10. Joint hyperlaxity Upper and lower limbs Total score range
0–1 0–1 0–1 0–8 0–8 0–1 0–1 0–1 0–1 0–1 0–2 0–2 0–2 0–2 0–2 0–2 0–1 0–5 0–2 0–1 0–2 0–2 0–8 0–2 0–2 0–1 0–100
components in 3 areas of competence, gross motor, fine motor, and graphic motor function. The 10 categories were selected and developed for the assessment by a pediatric physical therapist who is a senior lecturer in pediatrics in the medical faculty at the Tel Aviv University (LZ). Content validity of the Zuk Assessment tool was examined by 3 expert pediatric physical therapists, all of whom had 15 to 20 years of experience in the field of assessment and treatment of children with motor problems. They validated the inclusion of all the subtest items. Table 1 shows the 10 categories and the subtest
594 items of the Zuk. It includes standing and walking (6 items); static balance (2 items) and dynamic balance (3 items); changing posture (4 items); head and shoulder control and strength (2 items); sitting (8 items); graphic motor development (4 items); fine motor development (5 items); ability of the eyes to focus and follow (1 item); preferred eye and hand development (2 items), and finally joint hyperlaxity (1 item). The scoring method is simple and easy to use. Scores are calculated according to the successful achievement of the subtest item being examined. The total score is the sum of the scores of the subtest items examined in the 10 categories. Table 1 presents the score of each subtest item in each category. According to the items examined, children can score between 0 and 1, 0 and 2, 0 and 4, and 0 and 8. Each category has a different total maximal score that varies between 1 and 20. Finally the total score shows the level of function and motor performance of the child being examined. The higher score represents better performance. In 8 of the 10 categories examined, subtest items have identical evaluation scores for performance for ages 4 to 8 years inclusive. However, in the category of static and dynamic balance and tower building, the scores are age related and noted accordingly. Therefore, all age groups examined reflect the scores of the assessment tool. The manual of the test gives precise instructions on how to present, execute, and score each of the subtest items. The length of time taken to score the subtest item is not taken into consideration. Three trials are given for execution of each subtest item and the 2 most similar (best or worst) results record the score. Subtest items are presented verbally with the understanding, on the part of the examiner, that the child grasps the meaning of the instructions; if this is not so, then an interpreter needs to be present (this with regard to the diverse population in Israel). No practice runs of the subtests are given. Scoring of the results reflects the automatic level of motor function of the child being examined. Administration of the test is userfriendly, takes 35 to 45 minutes to execute, and requires a minimum of equipment.
Procedure In both the first and second steps of the study, each child was examined individually in a quiet, private room that was similarly set up for the assessment. Each room contained a free walking space of at least 5 to 6 m for testing the walking and balance subtest items, and a small table and chair for fine and grapho-motor examination. All equipment used for both the Movement Assessment Battery for Children and the Zuk Assessment was easily accessible to the examiner.
Reliability Step 1 of the study: In the population sample of 156 typically developing children, 28 (*20%) were randomly selected from the sample in order to undergo repeated measures. Intrarater reliability: From this group of 28 children, 15 children were randomly selected and examined and assessed at 2 different points in time (10-14 days’ interval) by 1 of the authors to record the intrarater reliability.13 Interrater reliability agreement was examined between one of the authors13 and a second physical therapist who was experienced in the use of the Zuk Assessment, on the remaining 13 of the 28 randomly chosen children simultaneously observing and noting their findings.
Journal of Child Neurology 29(5)
Validity To ensure that the subtest items represented all aspects of motor function included in the tool, the face and content validity were examined by 3 pediatric physical therapists with 15 to 20 years of experience and who were skilled in the use of motor assessments. Construct validity was assessed by examining the distribution of the scores in the total sample with the assumption that 5% to 10% would be identified with motor problems, and that a larger number of males would be identified. In the second step of the study, 151 children with suspected gross and/or fine motor problems who had been referred to child development centers, were examined with the Zuk and Movement Assessment Battery for Children assessment tools for validation of the Zuk Assessment. Each child was assessed with both the tools, 1 week apart in time and with a random choice of initial assessment (Movement Assessment Battery for Children or Zuk).
Statistical Analysis Normal distribution of the scores in the categories and the total score were evaluated with the Kolmogorov-Smirnov test (step 1). The t test was applied to compare scores between the subgroup of 13 and 15 participants that were chosen for intrarater and interrater reliability and the remaining group. Reliability for continuous scores was evaluated with intraclass correlation. For categorical variables, the Kappa and percentage agreement were used. Validation of the Zuk with the Movement Assessment Battery for Children: According to the cut-off of the Zuk Assessment, a 1-way analysis of variance model was applied to assess the differences in the Movement Assessment Battery for Children Assessment score; P .05 was considered statistically significant. All statistical analyses were performed using SPSS v. 17 software packages.
Results Step 1 Birth order was diverse in the sample, 145 children were born after a normal pregnancy and 11 after bed rest (mean gestational age [weeks] ¼ 39.63 + 2.00); 129 were born without any complications, 22 with caesarean intervention, 4 with vacuum birth, and 1 with forceps. Sixty-four children walked before 1 year of age. Mean age at entry into the study was 5.47 + .37 years. Gender was found to be split 78 boys and 78 girls. The ratio of boys to girls with motor problems was found to be 3:2. Joint hyperlaxity was present in 31 children. Subject score distribution in 10 categories and total score are presented in Table 2. Total score and category scores: The total average score was 79.5 (standard deviation ¼ 10) close to the median of 81 (Q1-Q3 ¼ 74-87). In the categories of standing/walking, changing posture, fine motor function, and preferred side, a ceiling effect could be seen as expected in a typically developing population.
Intrarater Reliability No difference in the total score was found between this group (n ¼ 15) and the remaining subjects (n ¼ 141; t test, P ¼ .2243). Results of the intrarater reliability included
Zuk et al
595
Table 2. Distribution of Subject Scores in 10 Categories and Total Score (n ¼ 156). Category 1. Stand/walk 2. Balance reaction 3. Posture change 4. Head and shoulders 5. Sitting 6. Fine motor 7. Blocks 8. Focus/Follow 9. Preferred side 10. Joint mobility Total score
Number items
Score range
M
Standard deviation
Median (P50)
Interquartile range (P25-P75)
6 5 4 2 8 5 4 1 2 1 38
0–6 0–20 0–15 0–16 0–11 0–12 0–7 0–8 0–4 0–1 0–100
5.4 14.1 14.6 12.3 7.1 10.6 4.9 6.3 3.4 0.8 79.5
0.8 4.8 1.0 3.9 1.6 1.5 1.4 2.4 1.0 0.4 10.0
6 15 15 12 7 11 5 8 4 1 81
5–6 11–18 15–15 8–16 6–8 10–12 4–6 6–8 2–4 1–1 74–87
Table 3. Reliability of Zuk Assessment by Intraclass Correlation Coefficients and Confidence Intervals. Intrarater reliability (n ¼ 15)
Interrater reliability (n ¼ 13)
Category
ICC
95% CI
P value
ICC
95% CI
P value
1. Stand/walk 2. Balance reaction 3. Posture change 4. Head and shoulders 5. Sitting 6. Fine motor 7. Blocks 8. Focus/follow 9. Preferred side 10. Joint mobility Final score
.42 .89 .20 .87 .28 .56 .27 .72 .42 .46 .89
0–.76 .71–.96 0–.63 .66–.96 0–.69 .12–.82 0–.69 .36–.89 0–.75 0–.78 .71–.96
.0596
