Graviceptive neglect after stroke: reversal with focal neuromodulation and investigation of the neuroanatomical basis

• Grant number: 23/03252-2
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2024
• End date: February 28, 2026
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Taiza Elaine Grespan Santos Edwards
• Grantee: Taiza Elaine Grespan Santos Edwards
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Antonio Carlos dos Santos ; Octávio Marques Pontes-Neto
• Associated research grant(s): 24/09711-1 - Graviceptive neglect after human brain lesion: clinical expression, recovery, neuroimaging and neurophysiological investigation, AP.R SPRINT
• Associated scholarship(s): 24/10007-7 - Clinical Research Training: Analysis of electroencephalography functional connectivity related to graviceptive neglect and response to Non-Invasive Brain Stimulation, BP.TT; 24/14343-1 - Clinical Research Training: Assessment of Post-Stroke Patients in a Randomized Controlled Trial on Non-Invasive Brain Stimulation to treat graviceptive neglect, BP.TT; 24/08028-6 - Clinical Research Training: Analysis of microstructural integrity using magnetic resonance imaging related to graviceptive neglect and response to Non-Invasive Brain Stimulation, BP.TT

Abstract

Stroke is one of the leading causes of disability globally, with poor functional recovery and a high risk of falling in the sub-acute phase, associated with an error in the perception of visual vertical (EPVV). Considered as graviceptive neglect, EPVV is a silent disorder present in the majority of patients and still untreatable. Non-invasive neuromodulation, in particular transcranial direct current stimulation (tDCS), is an emerging technique of interest to the research and clinical community. While tDCS offers potential as a treatment in stroke recovery, further formal controlled studies are required. Our prior findings indicate that post-stroke EPVV is rotated away from the lesioned hemisphere in the roll plane. We further showed that a focal tDCS montage (known as high-definition tDCS; HD-tDCS), unilaterally applied, can induce a remarkable and sustained rotation away from the stimulated hemisphere, when positioned over the temporo-parietal junction (TPJ; an integrative cortical hub in EPVV). Thus, we hypothesize that stimulating the contralesional TPJ in sub-acute stroke patients will correct the EPVV. This phase II randomized sham-controlled double-blind clinical trial aims to determine if HD-tDCS can safely correct EPVV in patients with first clinical stroke affecting either hemisphere. Neuroanatomical characteristics will be analyzed to establish the relationship of EPVV magnitude, and extent of TPJ damage, and more broadly the putative VV structural brain Network (VVN). Correlation analyses will also evaluate response to intervention, relative to VVN microstructural integrity, including principally the transcallosal TPJ tract. Our findings will have a public health impact because they will provide evidence for the development of future clinical intervention studies of a highly prevalent but still overlooked post-stroke disorder. (AU)