Evaluation of brain changes in stroke patients subjected to unilateral eccentric strength training combined with transcranial stimulation

• Grant number: 25/10777-0
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: July 01, 2025
• End date: February 28, 2029
• Field of knowledge: Physical Sciences and Mathematics - Physics - General Physics
• Principal Investigator: Gabriela Castellano
• Grantee: María Florencia Molina
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 13/07559-3 - BRAINN - The Brazilian Institute of Neuroscience and Neurotechnology, AP.CEPID

Abstract

Stroke is one of the main conditions that cause motor disabilities in people worldwide and in Brazil. Functional improvements may be scarce after stroke episodes, and functional disabilities resulting from this condition (such as hemiparesis) tend to worsen with the lack of effective exercises and rehabilitation programs. Previous studies in healthy adults have shown that unilateral exercises to strengthen muscles on only one side of the body (i.e., trained limbs) result in neuromuscular strength gains in the untrained contralateral limbs, which is a physiological phenomenon known as the cross-education effect (CEE). CEE is usually induced more effectively through strength exercises with eccentric contractions (active stretching) of the muscles. On the other hand, new technologies such as transcranial direct current stimulation (tDCS) have been used for the rehabilitation of stroke patients, with good results. tDCS is a neuromodulation technique with low-intensity stimulation of the brain that can increase the excitability of the primary motor cortex and improve motor performance in neurological patients. It is possible that the use of tDCS can enhance the EEC induced by eccentric contractions, although the combined use of these techniques as a rehabilitation method has not yet been investigated in stroke patients. Thus, the main objective of this project is to investigate brain changes resulting from EEC induced by eccentric contractions of non-paretic limbs (i.e., not affected by stroke), combined or not with tDCS, to induce motor improvements in paretic limbs (i.e., affected by stroke) in stroke patients with severe functional disabilities. To this end, patients will perform 4 weeks of unilateral eccentric strength training combined or not with the application of anodal tDCS in the motor cortex. Brain alterations will be assessed using functional magnetic resonance imaging (fMRI) and/or electroencephalography (EEG) scans, to which advanced signal processing and machine learning methods will be applied. This project is associated with a larger project submitted to FAPESP under the "Young Researcher" line by Dr. Cássio Ruas, co-advisor of this project, which aims to identify the acute and chronic effects of induced EEC in stroke patients. This project will also be carried out within the scope of CEPID BRAINN, of which the advisor is principal investigator, and which aims to conduct both basic and clinical research in neuroscience, with a focus on epilepsy and stroke, and the development of technologies that can aid in the diagnosis, prognosis and treatment of these diseases.