Fig 5. Effect of craniectomy on current density.

A. Current density distribution (color indication 0–180 A/m²) on the brain surface with and without craniectomy (no resection). The skin surface (with placed electrodes) is shown for orientation. Craniectomy significantly increases the current density in the region of pathology underlying the craniectomy (black ellipse, Fig 1C). This in turn leads to increased field strength in the affected region. B. Topographical distribution of the current density on the skin surface with and without craniectomy (range 0–250 A/m²). Craniectomy causes the current to be shunted through the skull defect thereby lowering the current density in the skin region between the active electrodes. The figure also shows how individual electrodes in the arrays contribute differently in the two situations.