Comparison of a TMS induced fields in homogeneous adult and child brain models using the surface integral equation approach

This paper gives a comparison of the numerical results for the induced electric field, electric current density and the magnetic flux density inside the adult, 10-year old and 5-year old homogeneous brain models, for three different transcranial magnetic stimulation (TMS) coils. The numerical results are obtained using the TMS model based on the surface integral equation (SIE) formulation. The models of a child brain are obtained by linearly scalling the adult brain model. The age dependent parameters of the brain are taken into account. The results showed the increased values of the TMS-evoked parameters in the smaller brain models. Further analysis is carried out to investigate to what degree does the approximation of brain tissue parameters influence the results in the homogeneous brain.