PDF(Pubmed)
Abstract：
Most of motor recovery usually occurs within the first 3 months after stroke. Herein is reported a remarkable late recovery of the right upper-limb motor function after a left middle cerebral artery stroke. This recovery happened progressively, from two to 12 years post-stroke onset, and along a proximo-distal gradient, including dissociated finger movements after 5 years. Standardized clinical assessment and quantified analysis of the reach-to-grasp movement were repeated over time to characterize the recovery. Twelve years after stroke onset, diffusion tensor imaging (DTI), functional magnetic resonance imaging (fMRI), and transcranial magnetic stimulation (TMS) analyses of the corticospinal tracts were carried out to investigate the plasticity mechanisms and efferent pathways underlying motor control of the paretic hand. Clinical evaluations and quantified movement analysis argue for a true neurological recovery rather than a compensation mechanism. DTI showed a significant decrease of fractional anisotropy, associated with a severe atrophy, only in the upper part of the left corticospinal tract (CST), suggesting an alteration of the CST at the level of the infarction that is not propagated downstream. The finger opposition movement of the right paretic hand was associated with fMRI activations of a broad network including predominantly the contralateral sensorimotor areas. Motor evoked potentials were normal and the selective stimulation of the right hemisphere did not elicit any response of the ipsilateral upper limb. These findings support the idea that the motor control of the paretic hand is mediated mainly by the contralateral sensorimotor cortex and the corresponding CST, but also by a plasticity of motor-related areas in both hemispheres. To our knowledge, this is the first report of a high quality upper-limb recovery occurring more than 2 years after stroke with a genuine insight of brain plasticity mechanisms.
摘要：
大多数运动恢复通常发生在中风后的前3个月内。本文报道了左大脑中动脉中风后右上肢运动功能的显着晚期恢复。这种恢复正在逐步发生，从中风发作后2到12年，沿着近端-远端梯度，包括5年后分离的手指运动。随着时间的推移，重复进行标准化的临床评估和对抓取运动的定量分析，以表征恢复情况。中风发作12年后,扩散张量成像(DTI),功能磁共振成像（fMRI），进行了皮质脊髓束的经颅磁刺激（TMS）分析，以研究假手运动控制的可塑性机制和传出途径。临床评估和量化的运动分析主张真正的神经系统恢复，而不是补偿机制。DTI显示分数各向异性的显著降低,与严重萎缩有关，仅在左皮质脊髓束（CST）的上部，提示CST在未向下游传播的梗死水平上的改变。右手的手指相对运动与广泛网络的fMRI激活有关，该网络主要包括对侧感觉运动区域。运动诱发电位正常，右半球的选择性刺激未引起同侧上肢的任何反应。这些发现支持以下观点：麻痹手的运动控制主要由对侧感觉运动皮层和相应的CST介导，还有两个半球运动相关区域的可塑性。据我们所知,这是首次报道卒中后超过2年的高质量上肢恢复，并真正了解了大脑可塑性机制。
