Department of Physical Therapy, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel; Loewenstein Rehabilitation Hospital, Ra'anana, Israel.
Loewenstein Rehabilitation Hospital, Ra'anana, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Clin Biomech (Bristol). 2021 Feb;82:105255. doi: 10.1016/j.clinbiomech.2020.105255. Epub 2020 Dec 24.
Upper-extremity reactions are part of a whole-body response to counterweight the falling center of mass after unexpected balance loss. Impairments in upper-extremity reactions due to unilateral hemiparesis may contribute to stroke survivors propensity for falling. We aimed to characterize upper-extremity (paretic and non-paretic sides) reactive movements in response to lateral balance perturbations in Persons with Stroke vs. healthy controls.
Twenty-six subacute persons with stroke and 15 healthy controls were exposed to multidirectional sudden unannounced surface translations in stance. Spatiotemporal parameters of upper- and lower-extremity balance responses to lateral perturbations were analyzed.
In both groups reactive upper-extremity movement initiation preceded reactive step initiation. In response to a loss of balance toward the paretic side, persons with stroke demonstrated delayed movement initiation of both upper- and lower-extremity compared with healthy controls (In persons with stroke: 234.7 ± 60.0 msec and 227.1 ± 39.6 msec for upper extremities vs. 272.1 ± 59.1 msec for lower-extremity; and in controls: 180.1 ± 39.9 msec and 197.8 ± 61.3 msec for upper-extremities vs. 219.3 ± 40.8 msec for lower-extremity; p = 0.001, Cohen's d's: 0.59-1.03) and a greater abduction excursion in the ipsilateral upper-extremity compared with the contralateral upper-extremity (In persons with stroke: 39.3 ± 23.6 cm vs. 24.9 ± 10.1 cm, respectively; In Controls: 42.6 ± 21.8 cm vs. 29.3 ± 17.3 cm, respectively).
The faster upper-extremity reactive movement reactions compared to reactive step initiation in both persons with stroke and healthy controls suggests that balance recovery is an automatic "reflex-like" response. Delayed upper-extremity reactive reactions in conditions of surface translation toward the non-paretic side in persons with stroke may increase the risk of falls in the direction of the paretic side.
上肢反应是身体对失去平衡后重心下降的整体反应的一部分。由于单侧偏瘫导致的上肢反应受损可能会增加中风幸存者跌倒的倾向。我们的目的是描述中风患者和健康对照组在应对侧向平衡干扰时，上肢（偏瘫侧和非偏瘫侧）的反应性运动。
26 名亚急性中风患者和 15 名健康对照者在站立位接受多方向突发、无预告的表面平移。分析上肢和下肢对侧向干扰的平衡反应的时空参数。
在两组中，上肢反应性运动的起始都先于反应性步的起始。在向偏瘫侧失去平衡时，中风患者的上肢和下肢的运动起始都比健康对照组延迟（在中风患者中：上肢为 234.7 ± 60.0 毫秒和 227.1 ± 39.6 毫秒，下肢为 272.1 ± 59.1 毫秒；而在对照组中：上肢为 180.1 ± 39.9 毫秒和 197.8 ± 61.3 毫秒，下肢为 219.3 ± 40.8 毫秒；p=0.001，Cohen's d's：0.59-1.03），并且同侧上肢的外展幅度大于对侧上肢（在中风患者中：39.3 ± 23.6 厘米 vs. 24.9 ± 10.1 厘米；在对照组中：42.6 ± 21.8 厘米 vs. 29.3 ± 17.3 厘米）。
中风患者和健康对照组的上肢反应性运动比反应性步的起始都更快，这表明平衡恢复是一种自动的“反射样”反应。在向非偏瘫侧进行表面平移的情况下，中风患者上肢反应性反应的延迟可能会增加向偏瘫侧跌倒的风险。
