Sport Sciences - Performance and Technology, Department of Health Science and Technology, Aalborg University, Niels Jernes Vej 12, 9220 Aalborg East, Denmark.
Sport Sciences - Performance and Technology, Department of Health Science and Technology, Aalborg University, Niels Jernes Vej 12, 9220 Aalborg East, Denmark.
Hum Mov Sci. 2021 Oct;79:102863. doi: 10.1016/j.humov.2021.102863. Epub 2021 Aug 18.
Pain impairs available cognitive resources and somatosensory information, but its effects on postural control during standing are inconclusive. The aim of this study was to investigate whether postural sway is affected by the presence of pain and a secondary task during standing.
Sixteen healthy subjects stood as quiet as possible at a tandem stance for 30s on a force platform at different conditions regarding the presence of pain and a secondary task. Subjects received painful stimulations on the right upper arm or lower leg according to a relative pain threshold [pain 7 out 10 on a Visual Analog Scale (VAS) - 0 representing "no pain" and 10 "worst pain imaginable"] using a computer pressurized cuff. The secondary task consisted of pointing to a target using a head-mounted laser-pointer as visual feedback. Center of Pressure (COP) sway area, velocity, mean frequency and sample entropy were calculated from force platform measures.
Compared to no painful condition, pain intensity (leg: VAS = 7; arm VAS = 7.4) increased following cuff pressure conditions (P < .01). Pain at the leg decreased COP area (P < .05), increased COP velocity (P < .05), mean frequency (P < .05) and sample entropy (P < .05) compared with baseline condition regardless the completion of the secondary task. During condition with pain at the leg, completion of the secondary task reduced COP velocity (P < .001) compared with condition without secondary task.
Pain in the arm did not affect postural sway. Rather, postural adaptations seem dependent on the location of pain as pain in the lower leg affected postural sway. The completion of a secondary task affected postural sway measurements and reduced the effect of leg pain on postural sway. Future treatment interventions could benefit from dual-task paradigm during balance training aiming to improve postural control in patients suffering from chronic pain.
疼痛会损害可用的认知资源和躯体感觉信息，但它对站立时姿势控制的影响尚无定论。本研究旨在探讨在站立时，疼痛和次要任务的存在是否会影响姿势摆动。
16 名健康受试者在不同的疼痛和次要任务条件下，以并足姿势尽可能安静地站在力台上 30s。根据相对疼痛阈值（视觉模拟评分 [VAS] 为 7 分-代表“无疼痛”，10 分-代表“可想象的最痛”），使用计算机加压袖带在右上肢或下肢施加疼痛刺激。次要任务是使用头戴式激光笔作为视觉反馈，指向目标。从中获得力台测量数据计算出中心压力（COP）摆动面积、速度、平均频率和样本熵。
与无痛条件相比，袖带加压后疼痛强度增加（腿部 VAS=7；手臂 VAS=7.4）（P<.01）。腿部疼痛降低了 COP 面积（P<.05），增加了 COP 速度（P<.05）、平均频率（P<.05）和样本熵（P<.05），与基线条件相比，无论是否完成次要任务。在腿部疼痛的条件下，与无次要任务条件相比，完成次要任务降低了 COP 速度（P<.001）。
手臂疼痛不会影响姿势摆动。相反，姿势适应似乎取决于疼痛的位置，因为腿部疼痛会影响姿势摆动。完成次要任务会影响姿势摆动测量结果，并降低腿部疼痛对姿势摆动的影响。未来的治疗干预措施可以从平衡训练中的双重任务范式中受益，旨在改善患有慢性疼痛的患者的姿势控制。
