An apparatus for electrical brain stimulation comprises a two dimensional electrode array designed to be implanted at the surface of the cortex of a person, said cortex having neural pre-identified nodes and including healthy cortical tissue and damaged cortical tissue, said damaged cortical tissue having at least one parameter of cortical waves which is different from parameter of healthy cortical tissue, said at least one parameter being one of cortical wave propagation speed, amplitude and frequency, said electrode array including electrodes for emitting stimulation electrical signals in the cortex and measuring electrical cortical waves in the cortex, and said electrode array being designed to cover at least part of said healthy cortical tissue and said damaged cortical tissue.