Lowry Kristin A, Smiley-Oyen Ann L, Carrel Andrew J, Kerr John P
Department of Kinesiology, Iowa State University, Ames, Iowa 50011, USA.
Mov Disord. 2009 Jan 30;24(2):261-7. doi: 10.1002/mds.22352.
Kinematic changes in Parkinson's disease (PD) gait are well documented; however, upper body dynamics are less understood. Harmonic ratios (HRs) measure the rhythm of trunk accelerations and can be examined in the vertical, anterior-posterior, and mediolateral planes, providing an indication of global walking stability (lower HR indicates poorer stability). We examined differences in HRs between persons with PD and healthy older adults and relationships between HRs and stride parameters. Eleven people with PD and 11 older adults walked over ground at their preferred pace. A triaxial accelerometer measured trunk accelerations. HRs and spatiotemporal parameters were calculated and standardized to remove the influence of gait velocity. The PD group exhibited lower HRs in all three planes, with the most pronounced differences in the mediolateral and anterior-posterior planes. Greater stride time variability was most closely associated with a lower anterior-posterior HR in PD and the presence of disease with the mediolateral HR. By demonstrating decreased walking stability in medial-lateral and anterior-posterior planes, we conclude that HRs offer unique information beyond that of typical stride parameters, and stride time variability is most closely associated with these direct measures of global walking stability.
帕金森病（PD）步态的运动学变化已有充分记录；然而，上身动力学的情况则了解较少。谐波比率（HRs）用于测量躯干加速度的节奏，可在垂直、前后和内外侧平面进行检测，从而为整体步行稳定性提供一个指标（较低的HR表明稳定性较差）。我们研究了帕金森病患者与健康老年人之间HRs的差异，以及HRs与步幅参数之间的关系。11名帕金森病患者和11名老年人以他们偏好的速度在平地上行走。一个三轴加速度计测量躯干加速度。计算HRs和时空参数并进行标准化，以消除步态速度的影响。帕金森病组在所有三个平面上的HRs均较低，在内外侧和前后平面上差异最为明显。在帕金森病患者中，更大的步幅时间变异性与较低的前后HR最为密切相关，而疾病的存在与内外侧HR相关。通过证明在内外侧和前后平面上步行稳定性降低，我们得出结论，HRs提供了超越典型步幅参数的独特信息，并且步幅时间变异性与这些整体步行稳定性的直接测量指标最为密切相关。
