Hemmati Ladan, Piroozi Soraya, Rojhani-Shirazi Zahra
Physical Therapy Department, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran.
J Back Musculoskelet Rehabil. 2018;31(3):489-497. doi: 10.3233/BMR-170992.
In patients with chronic low back pain (CLBP), postural control is a demanding task in terms of attention. Although the attentional demands of postural control have been investigated in these patients, the attentional demands of postural recovery during dual task performance have not been evaluated in patients with nonspecific CLBP.
To investigate the effect of dual tasking on anticipatory and compensatory postural adjustments in response to an external perturbation in patients with nonspecific CLBP.
Twenty-five patients with nonspecific CLBP of at least 3 months' duration and 25 healthy persons were exposed to predictable and unpredictable external perturbations. The attentional demands of postural adjustments were evaluated while participants simultaneously performed a cognitive task. Onset latency and integrated electromyographic activity of the trunk and leg muscles were compared between dual task (postural recovery and backward digit span memory) and single task conditions (postural recovery only).
The results showed delayed activation of the tibialis anterior (agonist) and early activation of the gastrocnemius (antagonist) muscles during the dual task in patients with nonspecific CLBP compared to healthy participants. Integrated electromyographic activity was significantly greater in the dual task than the single task condition in the gastrocnemius (antagonist) muscle in patients with nonspecific CLBP compared to healthy persons during unpredictable perturbations.
The impaired ankle muscle activities during a cognitive task suggest that postural control recovery following external perturbation requires attentional resources in patients with nonspecific CLBP. This may increase the risk of re-injury in people with nonspecific CLBP while they perform an attentionally demanding task in more difficult circumstances.
在慢性下腰痛（CLBP）患者中，姿势控制在注意力方面是一项具有挑战性的任务。尽管已经对这些患者姿势控制的注意力需求进行了研究，但非特异性CLBP患者在双重任务执行期间姿势恢复的注意力需求尚未得到评估。
研究双重任务对非特异性CLBP患者对外界干扰做出的预期和代偿性姿势调整的影响。
25名病程至少3个月的非特异性CLBP患者和25名健康人接受可预测和不可预测的外界干扰。在参与者同时执行认知任务时，评估姿势调整的注意力需求。比较双重任务（姿势恢复和倒背数字跨度记忆）和单一任务条件（仅姿势恢复）下躯干和腿部肌肉的起始潜伏期和积分肌电图活动。
结果显示，与健康参与者相比，非特异性CLBP患者在双重任务期间胫骨前肌（主动肌）激活延迟，腓肠肌（拮抗肌）激活提前。在不可预测的干扰期间，与健康人相比，非特异性CLBP患者腓肠肌（拮抗肌）在双重任务中的积分肌电图活动明显大于单一任务条件。
认知任务期间踝关节肌肉活动受损表明，非特异性CLBP患者在外界干扰后姿势控制恢复需要注意力资源。这可能会增加非特异性CLBP患者在更困难的情况下执行需要注意力的任务时再次受伤的风险。
