Structure Integrity of the Corticospinal Tracts Relates to the Motor Function of the Affected Lower Extremity n Stroke with Subcortical Infarction
Date Issued
2008
Date
2008
Author(s)
Luo, Zheng-An
Abstract
Backgrond and Purposes：This study aimed to find the differences of the structural integrity of bilateral corticospinal tracts (CST) between persons with subcortical infarction at the mid- and long-term durations after stroke (< 20-30 days (D30), 90th day (D90) and 180th day (D180)) and healthy adults, the changes of structural integrity in stroke group between the three times, and the relationships between the integrity of the affected CST and the motor function of the affected lower extremity.ethods：Five hemiplegic patients (63.1 ± 5.6 yrs) received clinical assessments and the diffusion spectrum imaging (DSI) scan at D30, D90 and D180, respectively. The motor function of the affected lower extremity was evaluated for each patient by the lower-extremity motor part of the Fugl-Meyer Assessment scale (FMA-LE). Five healthy adults who matched stroke with age, gender and footedness (64.3 ± 4.2 yrs) received clinical assessments and the DSI scan one time. For DSI data analysis, the generalized fractional anisotropy (GFA) and the relative GFA (rGFA) values of different segments (cerebral peduncle (CP), internal capsule (IC), above IC and above CP for both groups; below lesion, lesion and above lesion for stroke group only) of bilateral CSTs were calculated by tract-specific (TS) quantitative analysis for each subject. We also used the traditional region of interest (ROI) analysis to calculate the GFA and the rGFA values of bilateral posterior limb of the internal capsule (PLIC) for each subject so that we could understand the validity of the GFA and rGFA values by TS analysis. Independent t test was applied for comparions of the GFA and rGFA values between stroke and healthy groups. Two-way (hemisphere x post-stroke day) repeated measures of ANOVA was used to investigate differences in the GFA values of different segments of bilateral CSTs by TS analysis and those by ROI analysis between the three testing times. One-way (post-stroke day) repeated measures of ANOVA was used to investigate differences in the rGFA values of the CST by TS analysis and those by ROI analysis between the three testing times. Spearman correlation coefficient was used for the correlations between these GFA and rGFA values with the FMA-LE at three testing times concurrently and the correlations between these GFA and rGFA values at D30 and D90 with the FMA-LE at D90 and D180, respectively. esults：The GFA and rGFA values by TS analysis highly related to those by ROI analysis in stroke at all three testing times (r= 0.6-0.9). The GFA values of the affected CST in stroke at all three testing time, except the CP and IC segments at D180 were significantly lower than those of bilateral CSTs in healthy adults (p< 0.05), but the GFA values of the unaffected CST were the same as those of healthy adults (p> 0.05). Only the rGFA values of the IC segment at D30 and D90 in stroke were higher than those in healthy adults (p< 0.05). The GFA and the rGFA values of above lesion and above CP segments of the affected CST of the stroke changed between different testing times (p< 0.05). The rGFA value of the IC segment of the CST by TS analysis and by ROI analysis at D30 highly related to the FMA-LE at D90 and D180, respectively (r= -0.894, p= 0.041). The GFA and rGFA values of the lesion segment and the GFA value of the IC segment of the affected CST by TS analysis at D90 highly related to the FMA-LE at D90 and D180, respectively (r= 0.894, -0.894 and 0.894, p= 0.041). iscussion and Conclusions：The results indicate that the GFA and rGFA values by TS analysis have high validity due to high correlations between those values by TS analysis and by ROI analysis. Structural integrity of the affected CST highly relates to the motor function of the affected lower extremity concurrently and predictively. No significant change of structural integrity of the lesion segment of the affected CST was found due to different trends between patients with better motor recovery and those with poor recovery. In future, we can measure the test-retest reliability of the integrity in healthy adults, and find relationships between integrity of the affected CST and motor functions of the affected upper extremity in stroke and the differences of the changes between stroke with different severity.
Subjects
corticospinal tract
diffusion spectrum imaging
motor function of the lower extremity
stroke and correlation
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