Department of Rehabilitation and Movement Science, University of Vermont, 106 Carrigan Dr., Burlington, VT, USA.
Department of Communication Sciences and Disorders, University of South Carolina, 915 Greene St., Columbia, SC, USA.
Behav Neurol. 2021 Nov 11;2021:3010555. doi: 10.1155/2021/3010555. eCollection 2021.
Structural integrity of the ipsilesional corticospinal tract (CST) is important for upper limb motor recovery after stroke. However, additional neuromechanisms associated with motor function poststroke are less well understood, especially regarding the lower limb.
To investigate the neural basis of upper/lower limb motor deficits poststroke by correlating measures of motor function with diffusion tensor imaging-derived indices of white matter integrity (fractional anisotropy (FA), mean diffusivity (MD)) in primary and secondary motor tracts/structures.
Forty-three individuals with chronic stroke (time poststroke, 64.4 ± 58.8 months) underwent a comprehensive motor assessment and MRI scanning. Correlation and multiple regression analyses were performed to examine relationships between FA/MD in a priori motor tracts/structures and motor function.
FA in the ipsilesional CST and red nucleus (RN) was positively correlated with motor function of both the affected upper and lower limb ( = 0.36-0.55, ≤ 0.01), while only ipsilesional RN FA was associated with gait speed ( = 0.50). Ipsilesional CST FA explained 37.3% of the variance in grip strength ( < 0.001) and 31.5% of the variance in Arm Motricity Index ( = 0.004). Measures of MD were not predictors of motor performance.
Microstructural integrity of the ipsilesional CST is associated with both upper and lower limb motor function poststroke, but appears less important for gait speed. Integrity of the ipsilesional RN was also associated with motor performance, suggesting increased contributions from secondary motor areas may play a role in supporting chronic motor function and could become a target for interventions.
健侧皮质脊髓束（CST）的结构完整性对于中风后上肢运动功能的恢复很重要。然而，与中风后运动功能相关的其他神经机制尚不清楚，尤其是与下肢相关的。
通过将运动功能测量与弥散张量成像衍生的白质完整性指标（各向异性分数（FA）、平均弥散度（MD））相关联，来研究中风后上下肢运动缺陷的神经基础，这些指标与初级和次级运动束/结构相关。
43 名慢性中风患者（中风后时间，64.4 ± 58.8 个月）接受了全面的运动评估和 MRI 扫描。进行了相关和多元回归分析，以检验预先设定的运动束/结构中的 FA/MD 与运动功能之间的关系。
健侧 CST 和红核（RN）的 FA 与患侧上下肢的运动功能均呈正相关（ = 0.36-0.55， ≤ 0.01），而仅健侧 RN 的 FA 与步行速度相关（ = 0.50）。健侧 CST 的 FA 解释了握力（ < 0.001）和上肢运动能力指数（ = 0.004）的 37.3%和 31.5%的方差。MD 测量值不是运动表现的预测指标。
健侧 CST 的微观结构完整性与中风后上下肢的运动功能都有关，但对步行速度的影响较小。健侧 RN 的完整性也与运动表现相关，这表明来自次级运动区的增加的贡献可能在支持慢性运动功能方面发挥作用，并且可能成为干预的目标。
