Objective. Impaired trunk stability is frequent in spinal cord injury (SCI), but there is a lack of quantitative measures for assessing trunk function. Our objectives were to: (a) evaluate trunk muscle activity and movement patterns during a reaching task in SCI patients, (b) compare the impact of cervical (cSCI) and thoracic (tSCI) injuries in trunk function, and (c) investigate the effects of a startling acoustic stimulus (SAS) in these patients. Approach. Electromyographic (EMG) and smartphone accelerometer data were recorded from 15 cSCI patients, nine tSCI patients, and 24 healthy controls, during a reaching task requiring trunk tilting. We calculated the response time (RespT) until pressing a target button, EMG onset latencies and amplitudes, and trunk tilt, lateral deviation, and other movement features from accelerometry. Statistical analysis was applied to analyze the effects of group (cSCI, tSCI, control) and condition (SAS, non-SAS) in each outcome measure. Main results. SCI patients, especially those with cSCI, presented significantly longer RespT and EMG onset latencies than controls. Moreover, in SCI patients, forward trunk tilt was accompanied by significant lateral deviation. RespT and EMG latencies were remarkably shortened by the SAS (the so-called StartReact effect) in tSCI patients and controls, but not in cSCI patients, who also showed higher variability. Significance. The combination of EMG and smartphone accelerometer data can provide quantitative measures for the assessment of trunk function in SCI. Our results show deficits in postural control and compensatory strategies employed by SCI patients, including delayed responses and higher lateral deviations, possibly to improve sitting balance. This is the first study investigating the StartReact responses in trunk muscles in SCI patients and shows that the SAS significantly accelerates RespT in tSCI, but not in cSCI, suggesting an increased cortical control exerted by these patients.

客观的。躯干稳定性受损在脊髓损伤 (SCI) 中很常见，但缺乏评估躯干功能的定量措施。我们的目标是：(a) 评估 SCI 患者在到达任务期间的躯干肌肉活动和运动模式，(b) 比较颈部 (cSCI) 和胸部 (tSCI) 损伤对躯干功能的影响，以及 (c) 调查惊人的声学刺激 (SAS) 对这些患者的影响。方法。在需要躯干倾斜的到达任务期间，记录了 15 名 cSCI 患者、9 名 tSCI 患者和 24 名健康对照的肌电图 (EMG) 和智能手机加速度计数据。我们计算了按下目标按钮之前的响应时间 (RespT)、肌电图起始延迟和幅度，以及躯干倾斜、横向偏差和加速度计的其他运动特征。应用统计分析来分析组（cSCI、tSCI、对照）和条件（SAS、非 SAS）在每个结果测量中的影响。主要结果。SCI 患者，尤其是 cSCI 患者，其 RespT 和 EMG 发作潜伏期明显长于对照组。此外，在 SCI 患者中，躯干前倾伴有明显的侧向偏差。在 tSCI 患者和对照组中，SAS（所谓的 StartReact 效应）显着缩短了 RespT 和 EMG 潜伏期，但在 cSCI 患者中则不然，后者也表现出更高的变异性。意义. EMG 和智能手机加速度计数据的结合可以为 SCI 中躯干功能的评估提供定量测量。我们的结果显示 SCI 患者在姿势控制和补偿策略方面存在缺陷，包括延迟反应和较高的侧向偏差，可能是为了改善坐姿平衡。这是第一项研究 SCI 患者躯干肌肉的 StartReact 反应的研究，表明 SAS 显着加速了 tSCI 中的 RespT，但在 cSCI 中没有，表明这些患者施加的皮质控制增加。