Abstract：
Most children with hemiplegic cerebral palsy (HCP), one of the most prevalent subtypes of cerebral palsy, struggle with grasping and manipulating objects. This impairment may arise from a diminished capacity to properly direct forces created with the finger pad due to aberrant force application. Children with HCP were asked to create maximal force with the index finger pad in the palmar (normal) direction with both the paretic and non-paretic hands. The resulting forces and finger postures were then applied to a computational musculoskeletal model of the hand to estimate the corresponding muscle activation patterns. Subjects tended to create greater shear force relative to normal force with the paretic hand (p < 0.05). The resultant force was directed 33.6°±10.8° away from the instructed palmar direction in the paretic hand, but only 8.0°±7.3° in the non-paretic hand. Additionally, participants created greater palmar force with the non-paretic hand than with the paretic hand (p < 0.05). These differences in force production are likely due to differences in muscle activation pattern, as our computational models showed differences in which muscles are active and their relative activations when recreating the measured force vectors for the two hands (p < 0.01). The models predicted reduced activation in the extrinsic and greater reductions in activation in the intrinsic finger muscles, potentially due to reduced voluntary activation or muscle atrophy. As the large shear forces could lead to objects slipping from grasp, muscle activation patterns may provide an important target for therapeutic treatment in children with HCP.
摘要：
大多数儿童偏瘫脑瘫（HCP），脑瘫最常见的亚型之一,与抓住和操纵物体作斗争。这种损害可能起因于由于异常力施加而适当地引导指垫产生的力的能力减弱。要求患有HCP的儿童用食指垫在手掌（正常）方向上产生最大的力，同时使用麻痹手和非麻痹手。然后将所得的力和手指姿势应用于手的计算肌肉骨骼模型，以估计相应的肌肉激活模式。受试者倾向于使用麻痹手相对于法向力产生更大的剪切力(p<0.05)。合力在麻痹的手中指向远离指示的手掌方向33.6°±10.8°，但非麻痹手只有8.0°±7.3°。此外,参与者使用非麻痹手产生的手掌力大于使用麻痹手(p<0.05)。力产生的这些差异可能是由于肌肉激活模式的差异，如我们的计算模型显示，当重新创建两只手的测量力矢量时，肌肉活动及其相对活动的差异（p<0.01）。这些模型预测外在激活减少，内在手指肌肉激活减少，可能是由于自愿激活减少或肌肉萎缩。由于巨大的剪切力可能导致物体从抓握中滑落，肌肉激活模式可能为HCP患儿的治疗提供重要靶点.
