PDF(Pubmed)
Abstract：
Cerebral palsy (CP) is a neurologic injury that impacts control of movement. Individuals with CP also often develop secondary impairments like weakness and contracture. Both altered motor control and secondary impairments influence how an individual walks after neurologic injury. However, understanding the complex interactions between and relative effects of these impairments makes analyzing and improving walking capacity in CP challenging. We used a sagittal-plane musculoskeletal model and neuromuscular control framework to simulate crouch and nondisabled gait. We perturbed each simulation by varying the number of synergies controlling each leg (altered control), and imposed weakness and contracture. A Bayesian Additive Regression Trees (BART) model was also used to parse the relative effects of each impairment on the muscle activations required for each gait pattern. By using these simulations to evaluate gait-pattern specific effects of neuromuscular impairments, we identified some advantages of crouch gait. For example, crouch tolerated 13 % and 22 % more plantarflexor weakness than nondisabled gait without and with altered control, respectively. Furthermore, BART demonstrated that plantarflexor weakness had twice the effect on total muscle activity required during nondisabled gait than crouch gait. However, crouch gait was also disadvantageous in the presence of vasti weakness: crouch gait increased the effects of vasti weakness on gait without and with altered control. These simulations highlight gait-pattern specific effects and interactions between neuromuscular impairments. Utilizing computational techniques to understand these effects can elicit advantages of gait deviations, providing insight into why individuals may select their gait pattern and possible interventions to improve energetics.
摘要：
脑瘫（CP）是一种影响运动控制的神经系统损伤。患有CP的个体也经常发展为继发性损伤,如虚弱和挛缩。运动控制改变和继发性损伤都会影响神经系统损伤后个体的行走方式。然而,理解这些障碍之间的复杂相互作用和相对影响使得分析和改善CP中的步行能力具有挑战性。我们使用矢状平面肌肉骨骼模型和神经肌肉控制框架来模拟蹲下和非残疾步态。我们通过改变控制每条腿的协同作用的数量(改变的控制)来扰乱每个模拟，强加的虚弱和挛缩。还使用贝叶斯加性回归树(BART)模型来解析每种损伤对每种步态模式所需的肌肉激活的相对影响。通过使用这些模拟来评估神经肌肉损伤的步态模式特定效应，我们确定了克劳奇步态的一些优点。例如,crouch在没有和有改变的控制的情况下，可以耐受13%和22%的无残疾步态，分别。此外，BART表明，在非残疾步态期间，足底屈肌无力对总肌肉活动的影响是蹲下步态的两倍。然而,在存在vasti无力的情况下，crouch步态也是不利的:crouch步态增加了vasti无力对步态的影响，而不改变控制。这些模拟突出了步态模式的特定效应和神经肌肉损伤之间的相互作用。利用计算技术来理解这些影响可以引发步态偏差的优势，提供洞察为什么个人可以选择他们的步态模式和可能的干预措施，以提高能量学。
