Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo, 102-0083, Japan.
Exp Brain Res. 2019 Dec;237(12):3175-3183. doi: 10.1007/s00221-019-05656-2. Epub 2019 Oct 8.
Although no damage occurs in the brains of individuals with spinal cord injury, structural and functional reorganization occurs in the sensorimotor cortex because of the deafferentation of afferent signal input from below the injury level. This brain reorganization that is specific to individuals with spinal cord injury is speculated to contribute to the improvement of the motor function of the remaining upper limbs. However, no study has investigated in detail the motor function above the injury level. To clarify this, we designed an experiment using the handgrip force steadiness task, which is a popular technique for evaluating motor function as the index of the variability of common synaptic input to motoneurons. Fourteen complete spinal cord injury (cSCI) individuals in the chronic phase, fifteen individuals with lower limb disabilities, and twelve healthy controls participated in the study. We clarified that the force steadiness in the cSCI group was significantly higher than that in the control groups, and that sports years were significantly correlated with this steadiness. Furthermore, multiple analyses revealed that force steadiness was significantly predicted by sports years. These results suggest that brain reorganization after spinal cord injury can functionally affect the remaining upper limb motor function. These findings may have implications in the clinical rehabilitation field, such as occupational rehabilitation of the upper limbs. They also indicate that individuals with complete spinal cord injury, based on their enhanced force adjustment skills, would excel at fine motor tasks such as manufacturing and handicrafts.
尽管脊髓损伤患者的大脑没有受到损伤，但由于损伤以下部位传入信号输入的去传入，感觉运动皮层会发生结构和功能重组。这种特定于脊髓损伤患者的大脑重组被推测有助于改善剩余上肢的运动功能。然而，尚无研究详细研究损伤以上水平的运动功能。为了阐明这一点，我们使用手握力稳定性任务设计了一项实验，该任务是评估运动功能的常用技术，作为运动神经元共同突触输入变异性的指标。14 名慢性期完全性脊髓损伤（cSCI）患者、15 名下肢残疾患者和 12 名健康对照者参加了这项研究。我们明确指出，cSCI 组的力稳定性明显高于对照组，并且运动年限与这种稳定性显著相关。此外，多项分析表明，运动年限可以显著预测力稳定性。这些结果表明，脊髓损伤后的大脑重组可以对剩余的上肢运动功能产生功能性影响。这些发现可能对临床康复领域具有重要意义，例如上肢职业康复。它们还表明，基于增强的力量调整技能，完全性脊髓损伤患者将擅长制造和手工艺等精细运动任务。
