The microstructural status of the corpus callosum is associated with the degree of motor function and neurological deficit in stroke patients.

Yongxin Li,Fanrong Liang,Ping Wu,Wenhua Huang,Dezhong Yao

doi:10.1371/journal.pone.0122615

Yongxin Li, Fanrong Liang + Show 3 more

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https://doi.org/10.1371/journal.pone.0122615

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Abstract

Human neuroimaging studies and animal models have suggested that white matter damage from ischemic stroke leads to the functional and structural reorganization of perilesional and remote brain regions. However, the quantitative relationship between the transcallosal tract integrity and clinical motor performance score after stroke remains unexplored. The current study employed a tract-based spatial statistics (TBSS) analysis on diffusion tensor imaging (DTI) to investigate the relationship between white matter diffusivity changes and the clinical scores in stroke patients. Probabilistic fiber tracking was also used to identify structural connectivity patterns in the patients. Thirteen ischemic stroke patients and fifteen healthy control subjects participated in this study. TBSS analyses showed that the corpus callosum (CC) and bilateral corticospinal tracts (CST) in the stroke patients exhibited significantly decreased fractional anisotropy and increased axial and radial diffusivity compared with those of the controls. Correlation analyses revealed that the motor and neurological deficit scores in the stroke patients were associated with the value of diffusivity indices in the CC. Compared with the healthy control group, probabilistic fiber tracking analyses revealed that significant changes in the inter-hemispheric fiber connections between the left and right motor cortex in the stroke patients were primarily located in the genu and body of the CC, left anterior thalamic radiation and inferior fronto-occipital fasciculus, bilateral CST, anterior/superior corona radiate, cingulum and superior longitudinal fasciculus, strongly suggesting that ischemic induces inter-hemispheric network disturbances and disrupts the white matter fibers connecting motor regions. In conclusion, the results of the present study show that DTI-derived measures in the CC can be used to predict the severity of motor skill and neurological deficit in stroke patients. Changes in structural connectivity pattern tracking between the left and right motor areas, particularly in the body of the CC, might reflect functional reorganization and behavioral deficit.

Highlights

Stroke is a leading cause of long-term motor disability among adults
Compared with the healthy control group, probabilistic fiber tracking analyses revealed that significant changes in the inter-hemispheric fiber connections between the left and right motor cortex in the stroke patients were primarily located in the genu and body of the corpus callosum (CC), left anterior thalamic radiation and inferior fronto-occipital fasciculus, bilateral corticospinal tracts (CST), anterior/superior corona radiate, cingulum and superior longitudinal fasciculus, strongly suggesting that ischemic induces inter-hemispheric network disturbances and disrupts the white matter fibers connecting motor regions
The findings of the present study demonstrated that the diffusivity patterns in the stroke patients were changed

Summary

Introduction

Stroke is a leading cause of long-term motor disability among adults. Damages from ischemic stroke result in the functional and structural reorganization of perilesional and remote brain regions. Obtaining a better understanding of the structural-behavioral correlation after stroke is crucial to the development of effective therapies for patients. Connectivity approaches were used to explore this phenomenon to obtain a better understanding of whether the inter-hemispheric interaction was disrupted [5, 6]. A growing body of evidences suggests that pathological intra- and inter-hemispheric interactions among key motor regions are altered in stroke patients suffering from motor deficits [5,6,7,8]. Carter et al [5] observed that patients suffering from stroke-induced motor deficits showed a significant correlation between the disruption of inter-hemispheric functional connectivity and upper extremity impairment scores. There is a growing awareness that disrupted interhemispheric functional interactions might underlie motor behavioral deficits [7]

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