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Electroencephalography Network Indices as Biomarkers of Upper Limb Impairment in Chronic Stroke
Published on: July 14, 2023
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Structural Connectivity Remote From Lesions Correlates With Somatosensory Outcome Poststroke
Chia-Lin Koh1,2,3,4, Chun-Hung Yeh5,3,6,7, Xiaoyun Liang1,3,8
1Neurorehabilitation and Recovery (C.-L.K., X.L., R.V., R.J.S., L.M.C.), Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
Stroke
|June 17, 2021
Summary
Stroke survivors show reduced white matter connectivity in brain regions distant from the lesion, impacting touch function. These findings highlight structural connectional diaschisis as a key factor in stroke recovery and sensory impairment.
Area of Science:
- Neuroscience
- Neurology
- Radiology
Background:
- White matter fiber connectivity changes remote to stroke lesions, known as structural connectional diaschisis, can affect stroke impairment and recovery.
- Previous limitations in tract-specific techniques hindered in vivo investigation of these remote changes in humans.
Purpose of the Study:
- To identify and quantify white matter tracts affected by stroke lesions.
- To investigate the link between reduced tract-specific connectivity and impaired touch discrimination after stroke.
Main Methods:
- Fixel-based analysis applied to diffusion magnetic resonance imaging data from 37 stroke patients and 26 healthy adults.
- Comparison of fiber density, fiber-bundle cross-section, and a combined measure reflecting axonal structural connectivity between groups.
Main Results:
- Stroke patients exhibited reduced fiber-bundle cross-section and fiber density in four brain regions involved in somatosensory and spatial processing compared to controls.
- Reduced structural connectivity in the lesioned hemisphere's somatosensory fibers correlated with contralateral hand touch function.
- Ipsilesional hand touch function was linked to superior longitudinal fasciculus connectivity and, in right-lesion cases, the corpus callosum.
Conclusions:
- Tract-specific reductions in axonal connectivity within the somatosensory network are evident post-stroke.
- These remote white matter connectivity changes, indicative of structural connectional diaschisis, are associated with touch impairments in stroke patients.
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