Balance in children with attention deficit hyperactivity disorder-combined type

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<ul><li><p>age children; thearchers have paider, 2003; Schlee,</p><p>Research in Developmental Disabilities 35 (2014) 12521258</p><p>A R T I C L E I N F O</p><p>Article history:</p><p>Received 10 January 2014</p><p>Accepted 8 March 2014</p><p>Available online</p><p>Keywords:</p><p>Attention decit hyperactivity disorder</p><p>(ADHD)</p><p>Balance ability</p><p>Dynamic sitting</p><p>Mechanical horseback riding</p><p>Motion analysis</p><p>A B S T R A C T</p><p>The balance ability in children with attention decit hyperactivity disorder-combined</p><p>type (ADHD-C) has not been fully examined, particularly dynamic sitting balance.</p><p>Moreover, the ndings of some published studies are contradictory. We examined the</p><p>static and dynamic sitting balance ability in 20 children with ADHD-C (mean age: 9 years 3</p><p>months; 18 boys, 2 girls) and 20 age-, sex-, height-, weight-, and IQ-matched healthy and</p><p>typically developing controls (mean age: 9 years 2 months; 18 boys, 2 girls). The balance</p><p>subtests of the Movement Assessment Battery for Children (MABC) and the Bruininks-</p><p>Oseretsky Test of Motor Prociency (BOTMP) were used to compare the two groups, and a</p><p>mechanical horseback riding test was recorded using amotion-capture system. Compared</p><p>with the controls, children with ADHD-C had less-consistent patterns of movement, more</p><p>deviation of movement area, and less-effective balance strategies during mechanical</p><p>horseback riding. In addition, their performance on the balance subtests of the MABC and</p><p>BOTMP were not as well as those of the controls. Our ndings suggest that balance ability</p><p>skill levels in children with ADHD-C were generally not as high as those of the controls in</p><p>various aspects, including static and dynamic balance.</p><p> 2014 Elsevier Ltd. All rights reserved.</p><p>Contents lists available at ScienceDirect</p><p>Research in Developmental DisabilitiesNeubert, Worenz, &amp; Milani, 2012; Tseng, Henderson, Chow, &amp; Yao, 2004). Adequate balance ability is important for manydaily activities (Larkin &amp; Hoare, 1992). Insufcient balance ability negatively affects not only childrens motor performancebut also the psychosocial aspect of their life (Shum &amp; Pang, 2009; Simeonsson et al., 2003). Some studies (Piek et al., 1999;Shum &amp; Pang, 2009; Tseng et al., 2004) on children with ADHD-combined type (ADHD-C) report that their balance issignicantly less procient than that of matched controls without ADHD, but this nding was not consistent with other1. Introduction</p><p>Attention decit hyperactivity disorder (ADHD) is one of the most common disorders in school-worldwide-pooled prevalence is 5.29% (Polanczyk, de Lima, Horta, Biederman, &amp; Rohde, 2007). Some reseattention to the balance ability in children with ADHD (Piek, Pitcher, &amp; Hay, 1999; Raberger &amp; WimmBalance in children with attention decit hyperactivitydisorder-combined type</p><p>Hsun-Ying Mao a, Li-Chieh Kuo b, Ai-Lun Yang c, Chia-Ting Su d,*aDepartment of Physical Medicine &amp; Rehabilitation, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, TaiwanbDepartment of Occupational Therapy, College of Medicine, National Cheng Kung University, Tainan, TaiwancGraduate Institute of Exercise Science, University of Taipei, Taipei, TaiwandDepartment of Occupational Therapy, College of Medicine, Fu Jen Catholic University, New Taipei City, Taiwanreports (Pitcher, Piek, &amp; Hay, 2003).</p><p>* Corresponding author at: Department of Occupational Therapy, College of Medicine, Fu Jen Catholic University, 510 Zhongzheng Road, Xinzhuang Dist.,</p><p>New Taipei City 24205, Taiwan. Tel.: +886 2 2905 2091; fax: +886 2 2904 6743.</p><p>E-mail addresses:, (C.-T. Su).</p><p></p><p>0891-4222/ 2014 Elsevier Ltd. All rights reserved.</p></li><li><p>H.-Y. Mao et al. / Research in Developmental Disabilities 35 (2014) 12521258 12531.1. ADHD and balance ability</p><p>Piek et al. (1999) used theMovement Assessment Battery for Children (MABC) to assessmotor performance in 16 childrenwith ADHD-predominantly inattentive type (ADHD-PI), 16 children with ADHD-C, and a group of 16 age- and verbal-IQ-matched children without ADHD (controls). Their results showed that children with ADHD-PI had signicantly poorer nemotor skills. . . [and that those]with ADHD-C had signicantly greater difcultywith grossmotor skill than did the controls.Consistently, Tseng et al. (2004) found that children with ADHD-C demonstrated poorer balance as measured by theBruininks-Oseretsky Test of Motor Prociency (BOTMP). However, in another MABC-based study on balance in 104 boyswith ADHD and 39 controls without (Pitcher et al., 2003), they found no signicant differences in the static and dynamicbalance subtest results. Thus, the question of balance ability in children with ADHD-C is still open.</p><p>1.2. ADHD and dynamic balance ability</p><p>Although the MABC and BOTMP balance subtests can tell us something about balance performance, they are lessinformative about dynamic balance performance and balance strategies (Hatzitaki, Zisi, Kollias, &amp; Kioumourtzoglou, 2002).In daily life, dynamic balance ability is required for many tasks (Shumway-Cook &amp; Woollacott, 2007). Because few studieshave investigated dynamic balance in children with ADHD, we used a (dynamic) mechanical horse and a motion analysissystem in our study.</p><p>1.3. Purposes of this study</p><p>The aim of our study was to examine the static and dynamic balance ability of children with ADHD-C. To our knowledge,this was the rst studymeasuring dynamic balance ability in childrenwith ADHD by using the objectivemotion analysis andmechanic horse. We hypothesized that children with ADHD-C would have static and dynamic balance performance levelsthat differed signicantly from those of children without ADHD.</p><p>2. Methods</p><p>2.1. Participants</p><p>Forty children (age range: 6 years 8 months12 years 4 months) were recruited from elementary schools in southernTaiwan. Twenty of them, 18 boys and 2 girls (mean age: 9 years 3 months [SD: 1 year 4 months]; age range: 7 years 7months12 years 4 months), were diagnosed with ADHD-C by child psychiatrists using the criteria from the Diagnostic andStatistical Manual of Mental Disorders-4th edition (DSM-IV; American Psychiatric Association, 1994). The 20 controls, 18boys and 2 girls, were between 6 years 10months and 11 years 4months (mean age: 9 years 2months [SD: 1 year 2months]).There were no signicant differences in age, height, or weight between the two groups. All participants met the age-equivalent score on the Similarities and Vocabulary subtests of the Wechsler Intelligence Scale for Children, 3rd edition(WISC-III). These two subtests were chosen because the combination of their results was viewed as one of the best indicatorsfor general cognitive ability (Sattler, 1992). The manual muscle test (MMT) was used to screen out children with abnormalmuscle strength that might affect the balance measurements; all the recruited children met the level of good or normalstrength. To conrm the grouping, a parental questionnaire to screen children with ADHD, Conners Parent Rating Scale-Revised Short Form, was used to assess all of the participants. The results supported the diagnosis of ADHD for each child inthe ADHD group, and indicated that none of the controls had the symptoms of ADHD.</p><p>2.2. Instruments</p><p>2.2.1. Qualisys motion capture system</p><p>Themotioncapturesystem(ProReex-MCU240;QualisysMedicalAB,Gothenburg,Sweden)usedwasapassiveoptoelectronickinematic analyzer with infrared cameras, a personal computer, and software. The camera unit used reected infrared light todetect the position of each retro-reective marker worn by participants. The motion data were captured at a sampling rate of100Hz. A digital Butterworth lter with a cutoff frequency of 10Hzwas used to eliminate high-frequency noise. Forty-ve retro-reective markers 20-mm in diameter were attached at different body landmarks (Fig. 1) to estimate the movement ofparticipants center of mass (COM). Three markers were set on the mechanical horse (one on the front and two on the rear) toprovide a base when analyzing the motion during horseback riding. During data collection, a trial that contained four completecycles (i.e., four repetitions of motion) was considered sufcient for analysis. Three parameters of balance were drawn from thecollected data: (1) consistency of COMdeviation in the four cycles: themore consistent the COMmovement between cycles, themore stable the balance strategy; (2) deviation of COMarea ratio: the ratio of the difference between the COMmovement area ofthehorse andparticipant to theCOMmovement areaof thehorse (i.e., the absolute valueof [COMmovementofhorse area COMmovement of participant area]/[COM movement of horse area]): the larger the ratio, the less skilled the participants ability toadjust bodymovementbasedonhowthemechanicalhorsemoves; and (3) the largestCOMdifferences inmediallateral (ML) andanteriorposterior (AP) directions duringmovement, which is the largest length in theML and APminus the smallest length in</p></li><li><p>[(Fig._1)TD$FIG] H.-Y. Mao et al. / Research in Developmental Disabilities 35 (2014) 125212581254the ML and AP directions of COMmovement during mechanical horseback riding. The larger the value of this parameter, thelarger range of movement needed to maintain balance in that direction.</p><p>2.2.2. Mechanical horse</p><p>A mechanical horse (Joba EU-6441; Matsushita Electric Industrial Co., Ltd., Japan) designed based on the movementpattern of a real horse (i.e., a gure of eight) was used in our study. It includes nine levels of speed (range: 0.551.29 Hz). Theriders rely on their dynamic sitting balance ability to maintain their posture and prevent themselves from falling.</p><p>2.2.3. Movement Assessment Battery for Children (MABC)</p><p>The MABC is designed for assessing the motor competence of 4- to 12-year-old children. It contains four age bands, andincludes eight different items (three for manual dexterity, two for ball skills, and three for static and dynamic balance) ratedon a 6-point (05) scale. A higher score means greater motor impairment. The test has acceptable validity and reliability(Henderson &amp; Sugden, 1992). We used the static and dynamic subtest to assess the balance ability of children, as did priorstudies (Piek et al., 1999; Pitcher et al., 2003; Raberger &amp; Wimmer, 2003; Tseng et al., 2004).</p><p>2.2.4. Bruininks-Oseretsky Test of Motor Prociency (BOTMP)</p><p>The BOTMP is designed to assess the gross and ne motor skills in children from 4 years 6 months to 14 years 6 monthsold. The battery composite is the sum of eight subtest scores: running speed and agility, balance, bilateral coordination,strength, upper-limb coordination, response speed, visual-motor control, and upper-limb speed and dexterity. Its validityand reliability were acceptable (Bruininks, 1978). We used its 8-item balance subtest to detect balance ability, as did Tsenget al., 2004.</p><p>2.3. Procedures</p><p>This study had ethical approval from the National Cheng Kung University Hospital Ethics Review Board (HumanExperiment and Ethics Committee). After obtaining the signed informed consent statements from all participants and their</p><p>Fig. 1. (A) Marker set (anterior view): twenty-eight circular markers were placed on the head, sternum, acromion (bilaterally), lateral elbow, wrist, anterior</p><p>superior iliac spine, medial ankle, foot (3rd metatarsal), and T-shaped markers for xed 3D position were placed on both thighs and legs. (B) Marker set</p><p>(posterior view): seventeen markers placed on C7, L3, sacrum, and bilaterally on the medial elbow, medial metacarpal, lateral and medial knees, lateral</p><p>ankle, and heel. The medial elbow (upper arrows, B), knee (lower arrows, B), and ankle (arrows, A) were removed after the landmarks had been orientated.</p></li><li><p>parents, the CPRS-R, MMT, and WISC-III Vocabulary and Similarities subtests were used to screen the participants for ourstudy. Tominimize the effects ofmedication on the outcomemeasures, childrenwith ADHD takingmedicationwere asked todiscontinue their medication for 2448 h before the tests. During the mechanical horseback riding, each participant wasinstructed to sit straight on the mechanical horse, look forward, and put both hands on the reins and both feet on thefootrests. A riding trial was performed for 10 s at a speed of 1.29 Hz (the maximum intensity of this mechanical horse). If thechildren moved their hands or feet from the supporter or if less than four cycles of movement were detected by our motionsystem, that trial was considered a failure. One or more trials were conducted until the required data were collected. All oour participants were able to complete mechanical horseback riding without falling down and demonstrate one successfutrial. Following the evaluation of dynamic sitting balance during mechanical horseback riding, participants were tested byusing the balance subtests from the MABC and BOTMP. A total session of evaluation lasted for 7090min, and participantswere given 3- to 5-min breaks between tests.</p><p>2.4. Statistical analysis</p><p>SPSS 15was used for all statistical analyses. The intraclass correlation coefcient (ICC) of the four cycles was calculated toassess the consistency of COMmovement during the mechanical horseback riding for each group. Independent t tests wereused to compare differences between the two groups in the mean of the deviation of the COM area ratio during the fourcycles and in the largest COM difference of ML and AP direction, and to analyze differences in the balance ability scores onthe MABC and BOTMP balance subtests. Signicance was set at p&lt; 0.05.</p><p>3. Results</p><p>Examples of representative COM movement indicated that the child with ADHD-C demonstrated a pattern (Fig. 2A)different from that of the typically developing child (Fig. 2B). Specically, the gure of movementwasmore unregulated andless similar to the gure of eight made by the mechanical horse (Fig. 2C) in the child with ADHD-C.</p><p>According to Rosner (2006), an ICC value smaller than 0.4 indicates poor reproducibility, and 0.40.75means fair-to-goodreproducibility. During the mechanical horseback riding, the ICC value was low (0.09; p = 0.17) for the patterns in the fourcycles in the children with ADHD-C. In the control group, the ICC value was acceptable (0.67; p&lt; 0.01) in all four cycles. Inaddition, the independent t test showed a signicantly larger deviation of the COM area ratio (p&lt; 0.05) and larger values for</p><p>H.-Y. Mao et al. / Research in Developmental Disabilities 35 (2014) 12521258 1255the largest COM difference in the ML (p&lt; 0.01) and AP (p&lt; 0.01) directions for the ADHD-C group (Table 1).</p><p>Table 1</p><p>Differences in center of mass movement during mechanical horseback riding.</p><p>Measure Controls (n = 20) ADHD-C (n = 20) t p-Value</p><p>Mean SD Mean SD</p><p>Deviation of COM 0.39 0.20 0.64 0.36 2.34** 0.01</p><p>ML direction 11.49 6.11 21.05 7.64 3.78** 0.00</p><p>AP direction 15.57 9.18 29.81 18.43 2.68** 0.01</p><p>Controls, typically developing children; ADHD-C, attention decit hyperactivity disorder-combined type; COM, center of mass; Deviation of COM,</p><p>deviation of COM area ratio; ML, mediallateral; ML direction, COM largest difference in ML; AP, anterio...</p></li></ul>


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