痉挛可能影响脑瘫患儿的步态。量化其在运动期间的发生是具有挑战性的。一种方法是确定运动学牵张反射阈值,通常在速度上,在被动评估期间,并在步态期间搜索它们的超标。这些阈值是通过肌电图发作检测算法确定的,它们的性能是可变的,对嘈杂的数据很敏感,因此可能缺乏一致性。本研究旨在评估从最大肌腱加速度确定速度拉伸反射阈值的可行性。招募了18名CP患儿,并进行了临床步态分析和比目鱼肌的全面仪器评估,腓肠肌外侧,半腱肌,和股直肌痉挛,用EMG,运动学,同时测量施加的力。使用受试者缩放的肌肉骨骼模型,我们确定了基于加速度的牵张反射速度阈值,并将其与基于EMG-Fonset测定的阈值进行了比较.根据生理标准,它们的一致性,即,如果阈值的时间在拉伸开始和痉挛捕获之间,进行了评估。最后,设计用于评估步态过程中痉挛发生的两个参数,即,步态速度高于速度阈值的步态试验时间的比例和超过阈值的次数,进行了比较。所提出的方法产生的速度拉伸反射阈值接近基于EMG的阈值。对于所有的肌肉,设计用于评估步态痉挛发生的两个参数之间没有发现统计学差异。与基于EMG的方法相反,所提出的方法总是提供生理上一致的值,中值机电延迟在50到130毫秒之间。对于所有科目,步态过程中的半腱肌速度通常超过其伸展反射阈值,而其他三块肌肉的频率较低。我们得出的结论是速度拉伸反射阈值,基于肌肉的加速度,是基于EMG的可靠替代品。
Spasticity might affect gait in children with cerebral palsy. Quantifying its occurrence during locomotion is challenging. One approach is to determine kinematic stretch reflex thresholds, usually on the velocity, during passive assessment and to search for their exceedance during gait. These thresholds are determined through EMG-Onset detection algorithms, which are variable in performance and sensitive to noisy data, and can therefore lack consistency. This study aimed to evaluate the feasibility of determining the velocity stretch reflex threshold from maximal musculotendon acceleration. Eighteen children with CP were recruited and underwent clinical gait analysis and a full instrumented assessment of their soleus, gastrocnemius lateralis, semitendinosus, and rectus femoris spasticity, with EMG, kinematics, and applied forces being measured simultaneously. Using a subject-scaled musculoskeletal model, the acceleration-based stretch reflex velocity thresholds were determined and compared to those based on EMG-Onset determination. Their consistencies according to physiological criteria, i.e., if the timing of the threshold was between the beginning of the stretch and the spastic catch, were evaluated. Finally, two parameters designed to evaluate the occurrence of spasticity during gait, i.e., the proportion of the gait trial time with a gait velocity above the velocity threshold and the number of times the threshold was exceeded, were compared. The proposed method produces velocity stretch reflex thresholds close to the EMG-based ones. For all muscles, no statistical difference was found between the two parameters designed to evaluate the occurrence of spasticity during gait. Contrarily to the EMG-based methods, the proposed method always provides physiologically consistent values, with median electromechanical delays of between 50 and 130 ms. For all subjects, the semitendinosus velocity during gait usually exceeded its stretch reflex threshold, while it was less frequent for the three other muscles. We conclude that a velocity stretch reflex threshold, based on musculotendon acceleration, is a reliable substitute for EMG-based ones.