Structural connectivity changes in the motor execution network after stroke rehabilitation

Abstract

Background: Although quite a very few studies have tested structural connectivity changes following an intervention, it reflects only selected key brain regions in the motor network. Thus, the understanding of structural connectivity changes related to the motor recovery process remains unclear. Objective: This study investigated structural connectivity changes of the motor execution network following a combined intervention of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) and intensive occupational therapy (OT) after a stroke using graph theory approach. Methods: Fifty-six stroke patients underwent Fugl-Meyer Assessment (FMA), Wolf Motor Function Test-Functional Ability Scale (WMFT-FAS), diffusion tensor imaging (DTI), and T1 weighted imaging before and after the intervention. We examined graph theory measures related to twenty brain regions using structural connectomes. Results: The ipsilesional and contralesional hemisphere showed structural connectivity changes post-intervention after stroke. We found significantly increased regional centralities and nodal efficiency within the frontal pole and decreased degree centrality and nodal efficiency in the ipsilesional thalamus. Correlations were found between network measures and clinical assessments in the cuneus, postcentral gyrus, precentral gyrus, and putamen of the ipsilesional hemisphere. The contralesional areas such as the caudate, cerebellum, and frontal pole also showed significant correlations. Conclusions: This study was helpful to expand the understanding of structural connectivity changes in both hemispheric networks during the motor recovery process following LF-rTMS and intensive OT after stroke.

Motor network reorganization after motor imagery training in stroke patients with moderate to severe upper limb impairment

“…There are connections between the anterior portion of the putamen and associated regions exist in the cortex; the posterior portion of the putamen connects to the primary motor cortex and the supplementary motor area 62 . Available evidence suggests that subcortical regions such as the putamen and thalamus are important regulators of fine motor rehabilitation with previously learned movements 63 . Enhanced FCs from the putamen to primary motor regions has been reported in patients with Parkinson's disease 64 and stroke 65 .…”

“…62 Available evidence suggests that subcortical regions such as the putamen and thalamus are important regulators of fine motor rehabilitation with previously learned movements. 63 Enhanced FCs from the putamen to primary motor regions has been reported in patients with Parkinson's disease 64 and stroke. 65 A resting-state FC study revealed that the increased FC from the contralesional thalamus in patients with supratentorial stroke compared with healthy individuals and was correlated positively with motor improvement at 6-month follow-up.…”

Changes in Structural Neural Networks in the Recovery Process of Motor Paralysis after Stroke

“…Magnetic resonance imaging including functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are used to elucidate functional and structural features of the brain. In recent years, DTI data, in particular, have been correlated with the improvement of post-stroke paralysis [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Applying a mathematical approach, namely, graph theory, to analysis of DTI data allows greater understanding of the structural neural networks of the brain [ 25 , 26 ].…”

“…Although changes in structural neural networks during recovery from motor paralysis after stroke have been reported [ 27 , 28 ], to the best of our knowledge, only Wanni Arachchige et al [ 24 ] have investigated the impact of LF-rTMS combined with intensive-OT on the structural neural networks in detail. Their study used the same LF-rTMS plus intensive-OT protocol as ours [ 24 ].…”

“…Although changes in structural neural networks during recovery from motor paralysis after stroke have been reported [ 27 , 28 ], to the best of our knowledge, only Wanni Arachchige et al [ 24 ] have investigated the impact of LF-rTMS combined with intensive-OT on the structural neural networks in detail. Their study used the same LF-rTMS plus intensive-OT protocol as ours [ 24 ]. However, they did not distinguish between left and right hemispheres to increase the number of cases available for analysis, and calculated network measures for only 20 motor-function-related regions in the cerebrum.…”