Variability of Supported Treadmill Stepping Movements and Its Relation to the Age of Walking Attainment in Preterm and Full-term Infants

• Main Authors: Yin-Ju Chen, 陳盈如
• Other Authors: Hong-Ji Luo
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/90851089728295116629

碩士 === 國立陽明大學 === 物理治療暨輔助科技學系 === 102 === Background and purposes: Preterm infants are at risk for motor impairments related to movement variability. We aimed to investigate the relationship between the variability of stepping movements and the age of walking attainment in infants, and to compare the differences of variability of stepping movements between preterm and full-term infants. Methods: Twenty-seven preterm and 19 full-term infants (GA=29±4 vs. 39±1 weeks; BW=1.2±0.6 vs. 3.4±0.5 kg) were examined for supported stepping on a treadmill (0.2 m/s) at 7 and 9 months and age of walking attainment (independent walking ≧5 consecutive steps). Three dimensional stepping movements were collected using 2 synchronized 60-Hz video cameras and were analyzed using the Peak Performance Motion Analysis System. Variability of stepping movements was indexed using approximate entropy (ApEn), modified multiscale entropy (MMSE), and standard deviation (SD). The associations between ApEn, MMSE, and SD of step variables and walking outcome were examined using linear regression analysis and Cox's proportional-hazards regression analysis. The differences of ApEn, MMSE, SD of step variables, and AIMS scores between preterm and full-term infants and across time, and the change of stepping variability from the second last trial to the last trial were examined using repeated measure Analysis of Variance (ANOVA). Results: Regression analysis exhibited that a higher 9-months ApEn of ankle angle, a higher 7-months SD of knee angle, a higher 9-months SD of knee velocity, and a higher 9-months SD of ankle velocity were significantly associated with an older age of walking attainment when adjusted for prematurity. A significant time*group interaction effect for the ApEn of hip angle, the MMSE of knee velocity and acceleration, hip acceleration, and the SD of ankle acceleration, a significant time effect for the ApEn of knee angle, and a significant group effect for the ApEn of knee velocity, the SD of hip angle, ankle angle, and ankle velocity for were found. Compare to the second last trial, a higher ApEn of ankle angle and acceleration, and knee velocity, a higher MMSE of knee velocity and acceleration, and ankle acceleration, and a lower SD of all the hip variables at the last test trial than the second last test trial, a higher SD of all the knee and ankle step variables were found at the last test trial. Discussion: Increased irregularity in the motor behavior might reflect the reduction in the adaptability of a system which lead to late achievement of independent walking. Results of MMSE without prediction and group differences might be caused from the inappropriate algorithm for the data in this study. Both linear and nonlinear measurements had prediction for age of walking attainment indicated that they could provide different aspect for movement variability during supported treadmill stepping in infants. In conclusion, there were differences of stepping variability between preterm and full-term infants and prediction of stepping variability for age of walking attainment. ApEn was a more appropriate measurement than MMSE for the variability of stepping movement patterns in this study. In addition, we found the variability of hip movement control increased as the independent walking accomplished, yet variability of knee and ankle movement control decreased.