Motor recovery of the paraplegic hand after stroke: A longitudinal functional MRI study

Abstract

AIM： To investigate the motor recovery of the paretic hands in post-stroke patients through a longitudinal functional MRI (fMRI) study.

METHODS：The experiment adopted 11 stroke patients who were admitted in Department of Neurology, the Second Affiliated Hospital of Sun Yat-Sen University between December 2003 and February 2006, with their informed consents. Using CT or MRI, they were diagnosed as cerebral infarction and hemorrhage involved in motor cortex, internal capsule, basal ganglia or brain stem. The grip strength of lesioned hands reduced to 4－ grade or below at onset, then recovered to over 4+ grade at convalescence stage, followed by the fMRI studies that were done at two and six months after stroke respectively. Simultaneously 15 healthy examinees at right handedness were taken as normal control group and also performed fMRI examination, including 7 cases in bilateral hands and 8 cases in right hands. Evaluation: ①Non-quantitative index was consisted of the activation location, appearance, scope and distribution in both sides of primary sensorimotor cortex (SM1), the activation rate of premotor cortex (PM), supplementary motor area (SMA), cingulate motor areas (CMA) and non-motor area.②Quantitative index: Activation volume of SM1 was calculated as the addition of activation volumes of each layer in SM1 area measured by region of interest (ROI)×layer thickness. Lateral index = (activation volume of contralateral SM1－activation volume of ipsilateral SM1)/(activation volume of contralateral SM1+activation volume of ipsilateral SM1).

RESULT: ①fMRI analysis of SM1 area in normal group: Activation area in patched or irregular shape was found in 2－6 layers above lateral ventricle of pre-postcentral gyri, and there were not the same activation between left and right hands, and among different individuals. However, no significant difference was present in the activation volume and lateral index of both hands (P > 0.05).②fMRI analysis of non-SM1 and non-motor area in normal group: Compared with SM1, the activation area of non-SM1 and non-motor area was obviously reduced. The activation rate was the highest in PM whereas the lowest in CMA, additionally much lower or disappeared in other motor areas, except temporal lobe and occipital lobe.③fMRI analysis of paretic hands after stroke: The MRI appearances of activation at both sides of SM1 were similar to that of normal group in longitudinal fMRI studies at 2, 6 months after stroke. The activation volumes in contralateral SM1 of paretic hands were similar to that of normal group, but that in ipsilateral SM1 was larger than that of normal group at 2 months. The lateral index of lesioned hands was smaller at 2 months than that at 6 months after stroke; no significant difference was found (P > 0.05).④Patients at 2 months of stroke: The activation volume in contralateral SM1 of paretic hands was identical with that of normal group (P > 0.05), but that in ipsilateral SM1 was significantly larger than that of normal group [(997±704), (195±152) mm3; (1 661±962), (352±399) mm3, t =4.312, 3.240, P < 0.05]. The lateral index of both hands was significantly lower than that of normal group (0.258±0.679, 0.853±0.104; 0.042±0.553, 0.726±0.299, t =－3.405, －3.285, P < 0.05).⑤Patients at 6 months of stroke: The activation volumes in contralateral SM1 of paretic hands were similar to that of normal group (P > 0.05), but larger than that of normal group in ipsilateral SM1 [(717±915), (195±152) mm3], with significant statistical difference for right paretic hands (t =2.201, P < 0.05) and with no significant statistic difference for left paretic hands (P > 0.05). The lateral index of both hands was lower than that of normal group, and there was no significant difference (P > 0.05).⑥fMRI analysis of paretic hands in non-SM1 and non-motor area: The activation volume of non-SM1 and non-motor area was smaller than that of SM1, and the activation rate of bilateral PM and CMA was higher at 2 months than at 6 months in non-SM1; Compared with activation rate at 6 months, the SMA presented higher activation rate in right hands at 2 months, whereas lower rate in left hands. In non-motor area, the rate was higher in left temporal lobe, left prefrontal and left parietal regions, but lower in thalamus and ganglia. Generally the difference was not significant between 2 months and 6 months after stroke.

CONCLUSION:For the post-stroke recovered patients, the contralateral SM1 activation volume is normal and stable in the early stage (2 months after stroke), but complemental phenomenon can be still found in the ipsilateral SM1 in the same stage, which disappears in the late stage (6 months).

Huang SQ, Liang BL, Wang YD, Zhong JL, Chen ZG.Motor recovery of the paraplegic hand after stroke: A longitudinal functional MRI study.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2007;11(22):4266-4270(China)
[www.zglckf.com/zglckf/ejournal/upfiles/07-22/22k-4266(ps).pdf]

摘要
目的：观察脑卒中后偏瘫手运动功能恢复后纵向fMRI表现。
方法：于2003－12/2006－02选择中山大学第二附属医院神经内科收治的脑卒中患者11例，为脑卒中组。经CT或MRI证实脑梗死、出血，病灶可以累及运动皮质、内囊、基底节或脑干。发病时患侧手握力至少减低到4－级或以下。康复期（到行fMRI时）握力恢复到4+级以上，所用康复方法不限。行fMRI检查时间分别在发病后2个月和6个月。患者均知情同意。同期选择健康体检者15例为正常对照组，均为右利手，其中7例完成双侧手运动fMRI，另8例仅完成右侧手运动fMRI。观察指标：①非量化指标：观察双侧主要感觉运动区（Primary sensorimotor cortex，SM1）的激活位置、形态、范围和分布，观察运动前区（Premotor cortex，PM）、补充运动区（Supplementary motor area，SMA）、角回运动区（Cingulate motor areas，CMA）和非运动区的激活出现率。②量化指标：测量SM1的激活体积：用感兴趣区技术测量每一层SM1区激活的面积，相加后乘以层厚。侧方指数按公式计算：侧方指数=（对侧SM1激活体积－同侧SM1激活体积）/（对侧SM1激活体积+同侧SM1激活体积）。
结果：①正常对照组受试者手运动SM1区fMRI表现：激活区在中央前后回区，可在侧脑室顶以上2~6个层面观察到。激活区的形态呈斑片或不规则状，不同个体或左右手之间不完全相同。右、左手运动的对侧SM1激活体积、同侧SM1激活体积和侧方指数相近，差异无显著性意义（P > 0.05）。②正常对照组受试者手运动非主要运动区和非运动区fMRI表现：非主要感觉运动区及非运动区的激活体积明显比SM1区小，以PM激活的出现率最高，CMA激活出现率最低，其他非运动区，除颞叶、枕叶外，出现率都比较低或无出现激活。③脑卒中后偏瘫手运动SM1区fMRI表现：在脑卒中后的2个月和6个月，无论哪侧患肢运动，在双侧SM1区均表现为斑片或不规则的激活影像，与正常对照组的激活区相似。脑卒中患者梗死后2个月与6个月右、左侧患手运动对侧SM1激活体积相近；梗死后2个月右、左侧患手运动同侧SM1激活体积大于梗死后6个月；梗死后2个月右、左侧患手运动侧方指数小于梗死后6个月；差异均无显著性意义（P > 0.05）。④脑卒中患者梗死后2个月：右、左侧患手运动时，对侧SM1激活体积与正常对照组接近，差异无显著性意义（P > 0.05）；同侧SM1激活体积明显大于正常对照组[分别为（997±704），（195±152）mm3；（1 661±962），（352±399）mm3]，差异有显著性意义（t =4.312，3.240，P < 0.05）。右、左手侧方指数明显小于正常对照组(分别为0.258±0.679，0.853±0.104；0.042±0.553，0.726±0.299)，差异有显著性意义（t =－3.405， －3.285，P < 0.05）。⑤脑卒中患者梗死后6个月：右、左侧患手运动时，对侧SM1激活体积与正常对照组接近，差异无显著性意义（P > 0.05）；右侧患手同侧SM1激活体积明显大于正常对照组[分别为（717±915），（195±152）mm3]，差异有显著性意义（t =2.201，P < 0.05）；左侧患手同侧SM1激活体积大于正常对照组，差异无显著性意义（P > 0.05）；右、左手侧方指数小于正常对照组，差异无显著性意义（P > 0.05）。⑥脑卒中后偏瘫手运动非主要运动区和非运动区fMRI表现：非主要运动各区和非运动区的激活体积比SM1区小，非主要运动区梗死后2个月时双侧PM、CMA激活区出现率均高于梗死后6个月；梗死后2个月时右侧SMA激活区出现率高于梗死后6个月，左侧SMA激活区出现率低于梗死后6个月。非运动区左颞叶区、左额前区、左顶后区激活出现率稍高，丘脑、基底节出现率稍低，梗死后2个月与6个月比较总体差别不大。
结论：脑卒中后康复者，其对侧SM1激活体积在早期（梗死后2个月）已趋向稳定，同侧SM1区早期仍有明显代偿现象，晚期（梗死后6个月）趋向正常。
关键词：脑卒中；纵向fMRI；运动功能

黄穗乔，梁碧玲，王艺东，钟镜联，陈志光.脑卒中后偏瘫手运动功能的恢复：纵向fMRI对照[J].中国组织工程研究与临床康复，2007，11(22):4266-4270 [www.zglckf.com/zglckf/ejournal/upfiles/07-22/22k-4266(ps).pdf