Evaluating transcranial magnetic stimulation (TMS) induced electric fields in pediatric stroke

Area of Science:

• Neuroscience
• Biomedical Engineering
• Pediatric Neurology

Background:

• Transcranial magnetic stimulation (TMS) is gaining traction for stroke rehabilitation.
• Its application in pediatric stroke presents unique challenges due to developing brains and pathologies.
• The impact of stroke lesions on TMS-induced electric fields in children remains unexplored.

Purpose of the Study:

• To investigate how brain lesions in children affect TMS-induced electric fields.
• To analyze the influence of lesions on electric field strength and distribution during TMS.
• To inform optimal TMS dosing and coil placement strategies for pediatric stroke patients.

Main Methods:

• Utilized finite element method (FEM) modeling for TMS electric field simulations.
• Created individualized head models from MRI scans of 6 children with unilateral cerebral palsy from perinatal stroke.
• Simulated TMS electric fields for coil placements over lesioned and non-lesioned brain hemispheres.

Main Results:

• Brain lesions significantly alter TMS electric field distribution in pediatric stroke.
• Group-level mean electric field strength showed no difference between lesioned and non-lesioned hemispheres.
• The lesioned hemisphere exhibited greater variability in electric field strength compared to the non-lesioned hemisphere.
• Coil-to-cortex distance remains a critical factor influencing TMS electric fields, even with lesions.

Conclusions:

• Lesions in pediatric stroke brains markedly influence TMS electric field patterns.
• Understanding these lesion-induced effects is crucial for safe and effective TMS therapy in children.
• Individualized modeling and careful consideration of coil placement are essential for optimizing TMS treatment in this population.