Cortical Reorganization of Early Somatosensory Processing in Hemiparetic Stroke

Jordan N. Williamson, William A. Sikora, Shirley A. James, Nishaal J. Parmar, Louis V. Lepak, Carolyn F. Cheema, Hazem H. Refai, Dee H. Wu, Evgeny V. Sidorov, Julius P.A. Dewald, Yuan Yang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

The cortical motor system can be reorganized following a stroke, with increased recruitment of the contralesional hemisphere. However, it is unknown whether a similar hemispheric shift occurs in the somatosensory system to adapt to this motor change, and whether this is related to movement impairments. This proof-of-concept study assessed somatosensory evoked potentials (SEPs), P50 and N100, in hemiparetic stroke participants and age-matched controls using high-density electroencephalograph (EEG) recordings during tactile finger stimulation. The laterality index was calculated to determine the hemispheric dominance of the SEP and re-confirmed with source localization. The study found that latencies of P50 and N100 were significantly delayed in stroke brains when stimulating the paretic hand. The amplitude of P50 in the contralateral (to stimulated hand) hemisphere was negatively correlated with the Fügl–Meyer upper extremity motor score in stroke. Bilateral cortical responses were detected in stroke, while only contralateral cortical responses were shown in controls, resulting in a significant difference in the laterality index. These results suggested that somatosensory reorganization after stroke involves increased recruitment of ipsilateral cortical regions, especially for the N100 SEP component. This reorganization delays the latency of somatosensory processing after a stroke. This research provided new insights related to the somatosensory reorganization after stroke, which could enrich future hypothesis-driven therapeutic rehabilitation strategies from a sensory or sensory-motor perspective.

Original languageEnglish (US)
Article number6449
JournalJournal of Clinical Medicine
Volume11
Issue number21
DOIs
StatePublished - Nov 2022

Funding

This work is supported by NIH R01 HD109157. This work was also supported by an American Heart Association Career Development Award (#932980), NIH R21HD099710, the Oklahoma Center for the Advancement of Science and Technology (OCAST) Health Research Program HR21-164, Oklahoma Shared Clinical and Translational Resources (U54GM104938) with an Institutional Development Award from National Institute of General Medical Sciences. Dr. Dewald’s time on this project was also supported by his NIH R01NS105759.

Keywords

  • EEG
  • cortical reorganization
  • hemiparetic stroke
  • sensorimotor system
  • somatosensory evoked potentials

ASJC Scopus subject areas

  • General Medicine

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