Functional network connectivity is altered in patients with upper limb somatosensory impairments in the acute phase post stroke: A cross-sectional study

PLoS One. 2018 Oct 12;13(10):e0205693. doi: 10.1371/journal.pone.0205693. eCollection 2018.

Abstract

Background: Aberrant functional connectivity in brain networks associated with motor impairment after stroke is well described, but little is known about the association with somatosensory impairments.

Aim: The objective of this cross-sectional observational study was to investigate the relationship between brain functional connectivity and severity of somatosensory impairments in the upper limb in the acute phase post stroke.

Methods: Nineteen first-ever stroke patients underwent resting-state functional magnetic resonance imaging (rs-fMRI) and a standardized clinical somatosensory profile assessment (exteroception and higher cortical somatosensation) in the first week post stroke. Integrity of inter- and intrahemispheric (ipsilesional and contralesional) functional connectivity of the somatosensory network was assessed between patients with severe (Em-NSA< 13/32) and mild to moderate (Em-NSA> 13/32) somatosensory impairments.

Results: Patients with severe somatosensory impairments displayed significantly lower functional connectivity indices in terms of interhemispheric (p = 0.001) and ipsilesional intrahemispheric (p = 0.035) connectivity compared to mildly to moderately impaired patients. Significant associations were found between the perceptual threshold of touch assessment and interhemispheric (r = -0.63) and ipsilesional (r = -0.51) network indices. Additional significant associations were found between the index of interhemispheric connectivity and light touch (r = 0.55) and stereognosis (r = 0.64) evaluation.

Conclusion: Patients with more severe somatosensory impairments have lower inter- and ipsilesional intrahemispheric connectivity of the somatosensory network. Lower connectivity indices are related to more impaired exteroception and higher cortical somatosensation. This study highlights the importance of network integrity in terms of inter- and ipsilesional intrahemispheric connectivity for somatosensory function. Further research is needed investigating the effect of therapy on the re-establishment of these networks.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Arm / innervation*
  • Arm / physiopathology
  • Cross-Sectional Studies
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Motor Cortex / diagnostic imaging
  • Motor Cortex / physiopathology
  • Nerve Net / physiopathology
  • Neuroimaging
  • Parietal Lobe / diagnostic imaging
  • Parietal Lobe / physiopathology
  • Sensorimotor Cortex / diagnostic imaging
  • Sensorimotor Cortex / physiopathology
  • Severity of Illness Index
  • Somatosensory Disorders / diagnostic imaging
  • Somatosensory Disorders / etiology*
  • Somatosensory Disorders / physiopathology
  • Stroke / complications*
  • Stroke / diagnostic imaging

Grants and funding

This work was supported by Scientific Research Flanders (FWO) [grant number 1189817N] (ND) and [grant number 1518814N](SM); the Promobilia Foundation [grant number 15060](SM); the Foundation Van Goethem Brichant (SM); the German Research Foundation [grant number SFB 936 – project C2](SK; GT; BC). All funding sources have no involvement in the conduct of the research and preparation of the article.