Department of Exercise and Sport Sciences & Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
J Neurophysiol. 2013 Feb;109(3):625-39. doi: 10.1152/jn.00218.2012. Epub 2012 Nov 7.
Neurophysiological markers of the central control of gait in children with cerebral palsy (CP) are used to assess developmental response to therapy. We measured the central common drive to a leg muscle in children with CP. We recorded electromyograms (EMGs) from the tibialis anterior (TA) muscle of 40 children with hemiplegic CP and 42 typically developing age-matched controls during static dorsiflexion of the ankle and during the swing phase of treadmill walking. The common drive to TA motoneurons was identified through time- and frequency-domain cross-correlation methods. In control subjects, the common drive consists of frequencies between 1 and 60 Hz with peaks at beta (15-25 Hz) and gamma (30-45 Hz) frequencies known to be caused by activity within sensorimotor cortex networks: this drive to motoneurons strengthens during childhood. Similar to this drive in control subjects, this drive to the least affected TA in the CP children tended to strengthen with age, although compared with that in the control subjects, it was slightly weaker. For CP subjects of all ages, the most affected TA muscle common drive was markedly reduced compared with that of their least affected muscle as well as that of controls. These differences between the least and most affected TA muscles were unrelated to differences in the magnitude of EMG in the two muscles but positively correlated with ankle dorsiflexion velocity and joint angle during gait. Time- and frequency-domain analysis of ongoing EMG recruited during behaviorally relevant lower limb tasks provides a noninvasive and important measure of the central drive to motoneurons in subjects with CP.
神经生理学标志物可用于评估脑瘫（CP）患儿步态的中枢控制发育反应。我们测量了 CP 患儿腿部肌肉的中枢共同驱动。我们记录了 40 名偏瘫 CP 患儿和 42 名年龄匹配的正常对照组在踝关节背屈和跑步机行走摆动相时胫骨前肌（TA）的肌电图（EMG）。通过时频域互相关方法识别 TA 运动神经元的共同驱动。在对照组中，共同驱动由 1 至 60 Hz 的频率组成，峰值位于 beta（15-25 Hz）和 gamma（30-45 Hz）频率，已知这些频率是由感觉运动皮层网络中的活动引起的：这种对运动神经元的驱动在儿童时期增强。与对照组中相似的驱动，CP 患儿中受影响最小的 TA 的这种驱动也随着年龄的增长而增强，尽管与对照组相比，它稍弱。对于所有年龄段的 CP 患者，最受影响的 TA 肌肉共同驱动与受影响最小的肌肉以及对照组相比明显减弱。受影响最小和最大的 TA 肌肉之间的这些差异与这两块肌肉的 EMG 幅度差异无关，但与步态时的踝关节背屈速度和关节角度呈正相关。在行为相关的下肢任务中募集的 EMG 的时频域分析为 CP 患者运动神经元的中枢驱动提供了一种非侵入性且重要的测量方法。
