Current clinical assessments evaluating selective voluntary motor control are measured on an ordinal scale. We combined the Selective Control of the Upper Extremity Scale (SCUES) with surface electromyography to develop a more objective and interval-scaled assessment of selective voluntary motor control. The resulting Similarity Index (SI) quantifies the similarity of muscle activation patterns. We aimed to evaluate the validity and reliability of this new assessment named SI_SCUES (Similarity Index of the SCUES) in children with upper motor neuron lesions. Thirty-three patients (12.2 years [8.8;14.9]) affected by upper motor neuron lesions with mild to moderate impairments and 31 typically developing children (11.6 years [8.5;13.9]) participated. We calculated reference muscle activation patterns for the SI_SCUES using data of 33 neurologically healthy adults (median [1st; 3rd quantile]: 32.5 [27.9; 38.3]). We calculated Spearman correlations (ρ) between the SI_SCUES and the SCUES and the Manual Ability Classification System (MACS) to establish concurrent validity. Discriminative validity was tested by comparing scores of patients and healthy peers with a robust ANCOVA. Intraclass correlation coefficients_2,1 and minimal detectable changes indicated relative and absolute reliability. The SI_SCUES correlates strongly with SCUES (ρ = 0.76, p < 0.001) and moderately with the MACS (ρ = −0.58, p < 0.001). The average SI_SCUES can discriminate between patients and peers. The intraclass correlation coefficient_2,1 was 0.90 and the minimal detectable change was 0.07 (8% of patients’ median score). Concurrent validity, discriminative validity, and reliability of the SI_SCUES were established. Further studies are needed to evaluate whether it is responsive enough to detect changes from therapeutic interventions.

目前评估选择性自主运动控制的临床评估是按序数尺度进行测量的。我们将上肢选择性控制量表 (SCUES) 与表面肌电图相结合，开发出一种更客观、间隔尺度的选择性自愿运动控制评估方法。由此产生的相似性指数 (SI) 量化了肌肉激活模式的相似性。_{我们的目的是评估这项名为 SI SCUES}（SCUES 相似指数）的新评估对于上运动神经元病变儿童的有效性和可靠性。33 名患有轻度至中度损伤的上运动神经元病变的患者（12.2 岁[8.8;14.9]）和 31 名正常发育的儿童（11.6 岁[8.5;13.9]）参与了研究。我们使用 33 名神经健康成年人的数据计算了 SI _SCUES的参考肌肉激活模式（中位数 [第一；第三分位数]：32.5 [27.9；38.3]）。我们计算了 SI _SCUES和 SCUES 以及手动能力分类系统 (MACS) 之间的 Spearman 相关性 (ρ)，以建立并发有效性。通过使用稳健的 ANCOVA 比较患者和健康同伴的分数来测试区分效度。组内相关系数_2,1和最小可检测变化表明相对和绝对可靠性。SI _SCUES与 SCUES 密切相关（ρ = 0.76，p  < 0.001），与 MACS 具有中等相关性（ρ = -0.58，p  < 0.001）。平均 SI _SCUES可以区分患者和同伴。组内相关系数_2,1为 0.90，最小可检测变化为 0.07（患者中位评分的 8%）。建立了SI _{SCUES的并行有效性、区分有效性和可靠性。}需要进一步的研究来评估它是否有足够的反应能力来检测治疗干预的变化。