背景與目的：發展協調障礙是指在動作協調功能方面產生缺陷，且此類動作功能障礙無法歸因於任何已知可能對動作問題產生影響之疾病症狀。發展協調障礙兒童除了動作功能表現不如一般正常發展兒童之外，這個族群另一個值得注意的特點為動作變異性高，有可能是因為他們動作控制系統發展未臻成熟或者是動作控制系統有所缺失。由未臻成熟或者是有缺失的動作控制系統控制的動作應該會需要較多注意力，本篇研究的目的在於使用雙重作業探討發展協調障礙兒童步行表現與注意力之間的關係。

方法：本研究共選取15位(11男，4女）4到6歲(5.5 ± 0.6歲)發展協調障礙兒童，以及30位(22男，8女，5.5 ± 0.6歲）在性別及年齡與發展協調障礙兒童相當的正常發展兒童。每位參與者均接受動作評估測驗，並於步道上進行步行測試。步行分單純步行及在進行另一項同時作業的情況下步行，同時作業包括動作類及認知類兩種類型，另外再分為簡單及困難兩種難易程度。步行表現分為步行效率（步頻、步行速度、以及步距）以及步行平衡表現（雙腳支撐期以及步寬)兩類來探討。統計分析採用t檢定比較兩個組別之間步行表現及認知類同時作業反應時間的差異。三因子變異數分析探討組別、類型、以及難易程度的主要效果及交互作用。

結果：步行速度、步距、步頻及雙腳站立期在不同雙重作業下有類似的變化趨勢。困難同時作業相對於簡單同時作業有比較大的影響；同時作業難易程度的影響對發展協調障礙兒童比正常兒童來得大；難易程度的效應在動作類型比較顯著。發展協調障礙兒童在同時作業類型與難易程度有比較顯著的交互作用。

結論：發展協調障礙兒童的步態表現明顯地比正常兒童受到同時作業更大的影響，動作類型的影響大於認知類型，困難同時作業的影響大於簡單同時作業。這樣的結果可能與發展協調障礙兒童發展未臻成熟或者是有所缺失的動作控制有關。

Background and Purposes: Developmental coordination disorder (DCD) refers to the difficulty in motor coordination and such difficulty cannot be explained by any general medical condition. Children with DCD present difficulty of motor skill and high variability of motor performance. The high variability of motor performance may imply that the motor control system in children with DCD is less developed or in deficit. A motor activity run by a less developed motor control system may need more attention. The purpose of this study, by means of a dual task paradigm was to investigate the relationship between walking performance and attention in children with DCD.

Methods: Fifteen children (11 boys, 4 girls) with DCD at the age of 4 to 6 years old (5.5 ±0.6 years) and 30 age and gender matched normal children (22 boys, 8 girls, age: 5.5 ± 0.6 years) were recruited. Each child received Movement ABC test and walking performance test. Walking performance was measured under single-task and dual-task. In dual-task trials, subjects have to perform a concurrent task while walking. Concurrent tasks included two types (motor and cognitive) and two difficulty levels (easy and difficult). Data of gait velocity, cadence, stride length, double support time and base of support were measured and described as walking efficiency and walking balance performance. Three-way analysis of variance with repeated measure was used to compare the main effect of group, type of task and level of task difficulty and their interactions.

Results: Velocity, cadence, stride length, and double support showed similar results. A concurrent task incurred a greater dual task cost upon walking when it was hard than when it was easy. The effect of task difficulty appeared to be more prominent in the DCD group than in the normal group. The effect of task difficulty appears to be larger for the motor concurrent task than for the cognitive task. The task difficulty by task type interaction is more prominent in the DCD group than in the normal group.

Conclusions: The walking performance of children with DCD was more affected than normal children with concurrent task. The effect of dual task cost was larger for the motor concurrent task than for the cognitive task and greater when the task is hard than when it is easy. These results implicate that children with DCD have less developed motor control and are more affected by a concurrent hard motor task.

American Psychiatric Association. (1994) Diagnostic and statistical manual of mental disorders. (4th ed.) . Washington DC: American Psychiatric Association.

Barnhart RC, Davenport MJ, Epps SB, Nordquist VM. (2003) Developmental coordination disorder. Phys Ther 83: 722-731.

Beauchet O, Dubost V, Gonthier R, Kressig RW. (2005) Dual-task-related gait changes in transitionally frail older adults: the type of the walking-associated cognitive task matters. Gerontology 51: 48-52.

Bilney B, Morris M, Webster K. (2003) Concurrent related validity of the GAITRite walkway system for quantification of the spatial and temporal parameters of gait. Gait Posture 17: 68-74.

Bond JM, Morris M. (2000) Goal-directed secondary motor tasks: their effects on gait in subjects with Parkinson disease. Arch Phys Med Rehabil 81: 110-116.

Brauer SG, Woollacott M, Shumway-Cook A. (2002) The influence of a concurrent cognitive task on the compensatory stepping response to a perturbation in balance-impaired and healthy elders. Gait Posture 15: 89-93.

Cermak SA, Gubbay SS, Larkin D. (2002) What is developmental coordination disorder? In: Cermak SA, Larkin D, editors. Developmental Coordination Disorder. Albany, NY: Delmar Thompson Learning. p 2-22.

Chow SMK, Henderson SE. (2003) Interrater and test-retest reliability of the movement assessment battery for Chinese preschool children. Am J Occup Ther 57: 574-577.

Crove RV, Horvat M, McCarthy E. (2001) Reliability and concurrrent validity of the movement assessment battery for children. Percept Mot Skills 93: 275-280.

Cutlip RG, Mancinelli C, Huber F, DiPasquale J. (2000) Evaluation of an instrumented walkway for measurement of the kinematic parameters of gait. Gait Posture 12: 134-138.

Ebersbach G, Dimitrijevic MR. (1995) Influence of concurrent tasks on gait: a dual-task approach. Percept Mot Skills 81: 107-113.

Estil LB, Ingvaldsen RP, Whiting HT. (2002) Spatial and temporal constraints on performance in children with movement co-ordination problems. Exp Brain Res 147: 153-61.

Forseth AK, Sigmundsson H. (2003) Static balance in children with hand-eye co-ordination problems. Child Care Health Dev 29: 569-579.

Gabell A, Nayak USL. (1984) The effect of age on variability in gait. J Gerontol 39: 662-666.

Geuze R, Börger H. (1993) Children who are clumsy: five years later. Adapt Phys Act Q 10: 10-21.

Gillberg C, Rasmussen P. (1982) Perceptual, motor and attentional deficits in seven-year-old children: background factors. Dev Med Child Neurol 24: 752-770.

Hall DMB. (1988) Clumsy children. Br Med J 296: 375-376.

Henderson SE, Hall D. (1982) Concomitants of clumsiness in young schoolchildren. Dev Med Child Neurol 24: 448-460.

Henderson SE, Sugden DA. (1992) Movement Assessment Battery for Children: Manual. London: Psychological Corporation.

Huang HJ, Mercer VS, Thorpe DE. (2003) Effects of different concurrent cognitive tasks on temporal-distance gait variables in children. Pediatr Phys Ther 15: 105-113.

Johnston, L. M., Burns, Y. R., Brauer, S. G., Richardson, C. A. (2003, March). The effect of dual-task demands on postural control in children with developmental coordination disorder. Paper presented at the XVIth conference of the International Society for Postural and Gait Research, New South Wales, Australia.

Kinchla RA. (1980) The measurement of attention. In: Nickerson RS, editor. Attention and performance VIII. Hillsdale, NJ: Lawrence Erlbaum Associates. p 213-238.

Lajoie Y, Teasdale N, Bard C, Fleury M. (1993) Attentional demands for static and dynamic equilibrium. Exp Brain Res 97:139-144.

Lajoie Y, Teasdale N, Bard C, Fleury M. (1996) Upright standing and gait: are there changes in attentional requirements related to normal aging? Exp Aging Res 22: 185-198.

Leemrijse C, Meijer OG, Vermeer A, Lambregs B, Adèr HJ. (1999) Detecting individual change in children with mild to moderate motor impairment: the standard error of measurement of the Movement ABC. Clin Rehabil 13: 420-429.

Marsh AP, Geel SE. (2000) The effect of age on the attentional demands of postural control. Gait Posture 12: 105-113.

McDonough AL, Batavia M, Chen FC, Kwon S, Ziai J. (2001) The validity and reliability of the GAITRite system's measurements: A preliminary evaluation. Arch Phys Med Rehabil 82: 419-425.

Menz HB, Latt MD, Tiedemann A, Mun San Kwan M, Lord SR. (2004) Reliability of the GAITRite walkway system for the quantification of temporo-spatial parameters of gait in young and older people. Gait Posture 20: 20-25.

Norlin R, Odenrick P, Sandlund B. (1981) Development of gait in the normal children. J Pediatr Orthop 1: 261-266.

Nutt JG, Marsden CD, Thompson PD. (1993) Human walking and higher-level gait disorders, particularly in the elderly. Neurology 43: 268-279.

O’Shea S, Morris ME, Iansek R. (2002) Dual task interference during gait in people with Parkinson disease: effects of motor versus cognitive secondary tasks. Phys Ther 82: 888-897.

Pashler H. (1994) Dual-task interference in simple tasks: data and theory. Psychol Bull 116: 220-244.

Pellecchia GL. (2003) Postural sway increases with attentional demands of concurrent cognitive task. Gait Posture 18:29-34.

Pless M, Carlsson M, Sundelin C, Persson K. (2002) Preschool children with developmental coordination disorder: a short-term follow-up of motor status at seven to eight years of age. Acta Paediatr 91: 521-528.

Pless M, Persson K, Sundelin C, Carlsson. (2001) Children with developmental co-ordination disorder: a qualitative study of parents; descriptions. Adv Physiother 3: 128-135.

Polatajko HJ, Fox AM, Missiuna C. (1995) An international consensus on children with developmental coordination disorder. Can J Occup Ther 62: 3-6.

Rankin JK, Woollacott MH, Shumway-Cook A, Brown LA. (2000) Cognitive influence on postural stability: a neuromuscular analysis in young and older adults. J Gerontol Med Sci 55: M112-119.

Roussounis SH, Gaussen TH, Stratton P. (1987) A 2-year follow-up study of children with motor coordination problems identified at school entry age. Child Care Health Dev 13: 377-391.

Teasdale N, Bard C, Larue J, Fleury M. (1993) On the cognitive penetrability of posture control. Exp Aging Res 19: 1-13.

VanSant AF. (1990) Life-span development in functional tasks. Phys Ther 70: 788-798.

van Uden CJ, Besser MP. (2004) Test-retest reliability of temporal and spatial gait characteristics measured with an instrumented walkway system (GAITRite). BMC Musculoskelet Disord 5: 13.

Van Waelvelde H, De Weerdt W, De Cock P, Smits-Engelsman BCM. (2004) Aspects of the validity of the Movement Assessment Battery for Children. Hum Mov Sci 23: 49-60.

Walton JN, Ellis E, Court SDM. (1962) Clumsy children: developmental apraxia and agnosia. Brain 85: 603-612.

Wickens CD. (1980) The structure of attentional resources. In: Nickerson RS, editor. Attention and performance VIII. Hillsdale, NJ: Lawrence Erlbaum Associates. p 239-258.

Wilde NJ, Strauss E, Tulsky DS. (2004) Memory span on the Wechsler Scales. J Clin Exp Neuropsychol 26: 539-549.

Williams HG, Fisher JM, Tritschler KA. (1983) Descriptive analysis of static postural control in 4, 6, and 8 year old normal and motorically awkward children. Am J Phys Med 62: 12-26.

Winter D. (1990) The biomechanics and motor control of human gait: normal, pathological, and elderly. 2nd ed., Waterloo, Ontario, Canada: University of Waterloo Press.

Woodruff, SJ, Bothwell-Myers, C., Tingley, M. & Albert WJ. (2002) Gait pattern classification of children with developmental coordination disorder. Adapt Phys Act Q 19: 378-391.

Wright HC, Sugden DA. (1996) The nature of developmental coordination disorder: inter- and intragroup differences. Adapt Phys Act Q 13: 357-371.

林冠宏、吳昇光。（民91）台灣地區七至八歲發展協調障礙兒童之研究。物理治療，27，238-248。

陳榮華。（民86）魏氏兒童智力量表第三版（中文版）指導手冊。台北市：中國行為科學社。