Effects in Brain Symmetry and Functional Connectivity of tDCS Combined With XR in Chronic Stroke

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Carlos, Bruna M. ; de Vazquez, Pedro F. G. ; Menezes, Lucas T. ; Feitosa, Saulo S. ; da Silva, Marcio V. N. ; Almeida, Sara R. M. ; Silvestre, Jayne A. F. ; Pontes, Larissa L. ; Brandao, Alexandre F. ; Ruas, Cassio V. ; Castellano, Gabriela

• Document type: Journal article
• Source: IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING; v. 33, p. 11-pg., 2025-01-01.

Abstract

This study examines the effects of combining transcranial direct current stimulation (tDCS) with extended reality (XR) exercises on brain connectivity and motor recovery in chronic stroke. We evaluate changes in electroencephalography (EEG) based connectivity and symmetry parameters, their correlation with clinical improvements, and their prognostic potential. Participants underwent XR rehabilitation with either active anodal tDCS or sham stimulation. EEG connectivity metrics and symmetry indices were assessed before and after the intervention alongside upper and lower limb motor function assessments. Correlation analyses were conducted to examine associations between EEG variations and motor improvements. As results, significant reductions in the brain symmetry index and the directional brain symmetry index were observed in the active tDCS group in the alpha, beta, and gamma EEG frequency bands, indicating an increase in symmetry after rehabilitation. Comparing the evolution of EEG features with clinical variations, in the active tDCS group greater correlations of changes in high frequency connectivity with upper and lower limb improvements were found. In conclusion, the addition of anodal tDCS to XR therapy seems to enhance neuroplasticity by modulating high-frequency power and connectivity, possibly also promoting more effective motor recovery. This study provides a comprehensive analysis of tDCS-enhanced XR rehabilitation, offering novel insights into brain connectivity changes and potential biomarkers for stroke recovery. (AU)

• FAPESP's process: 23/11024-0 - Functional connectivity changes in neurological patients
• Grantee: Bruna Mezzari Carlos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/03695-5 - Application and development of virtual reality tools to complement conventional therapy of stroke patients and evaluation of recovery using brain connectivity through fMRI
• Grantee: Alexandre Fonseca Brandão
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/08057-0 - Neuromodulation combined with other neurotechnologies for application in the motor rehabilitation of Stroke patients
• Grantee: Cássio Víctora Ruas
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 20/16571-0 - Investigation of brain changes in neurological patients undergoing different rehabilitation treatments
• Grantee: Bruna Mezzari Carlos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/07559-3 - BRAINN - The Brazilian Institute of Neuroscience and Neurotechnology
• Grantee: Fernando Cendes
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC