Local dynamic stability during treadmill walking can detect children with developmental coordination disorder

• Published in: Gait & posture 2018-01, Vol.59, p.99-103
• Main Authors: Speedtsberg, Merete B., Christensen, Sofie B., Stenum, Jan, Kallemose, Thomas, Bencke, Jesper, Curtis, Derek J., Jensen, Bente R.
• Format: Article
• Language: English
• Subjects: Acceleration; Accelerometry - methods; Child; Child Development; Developmental coordination disorder; Exercise Test - methods; Female; Gait - physiology; Gait stability; Humans; Local dynamic stability; Male; Motor Skills Disorders - diagnosis; Postural Balance - physiology; ROC Curve; Sensitivity and Specificity; Torso - physiology; Treadmill walking; Trunk accelerations; Walking - physiology
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2017.09.035

•Gait stability in children with Developmental coordination disorder.•Local dynamic stability quantified with the short term Lyapunov exponent.•Children with DCD have reduced local dynamic stability.•Anterior- Posterior Lyapunov exponent has good discriminative power. Developmental coordination disorder (DCD) is an innate impairment of motor coordination that affects basic locomotion and balance. This study investigated local dynamic stability of trunk accelerations during treadmill walking as an objective evaluation of gait stability and the sensitivity and specificity of this measure to discriminate children with DCD from typically developing children. Eight children with DCD and ten age- and gender-matched typically developing children (TD) walked four minutes on a treadmill. Trunk accelerations in vertical, medio-lateral and anterior-posterior directions were recorded with a sternum mounted accelerometer at 256Hz. Short term local dynamic stability (λs), root mean square (RMS) and relative root mean square (RMSR) were calculated from measures of orthogonal trunk accelerations. Receiver operating characteristic curve (ROC) analysis was performed to discriminate between groups based on short term local dynamic stability. λs was significantly greater in children with DCD in the main movement direction (AP) (DCD: 1.69±0.17 λs; TD:1.41±0.17 λs; p=0.005), indicating reduced local dynamic stability. RMS and RMSR accelerations showed no difference between children with DCD and TD children in any direction. The ROC analysis of λs in separate directions and in two dimensions showed an excellent accuracy of discriminating between children with DCD and TD children. Anterior-posterior direction in combination with medio-lateral or vertical showed best performance with an area under the curve (AUC) of 0.91. We have shown that children with developmental coordination disorder have general reduced local dynamic stability and that the short term Lyapunov exponent has good power of discrimination between DCD and TD.