Multielectrode system for transcranial stimulation and impedance imaging

Abstract

Recent works indicate that through the non-invasive application of low current waveforms to the brain, systems implementing both cortical stimulation (Transcranial Direct Current Stimulation) and imaging (Electrical Impedance Tomography) with a high degree of accuracy and effectiveness can be realised. Safety and physical constraints along with the individually unique and fractal-like functional, structural and electrical complexity of the brain and surrounding cranial tissue hinders legacy systems from achieving enough precision and effectiveness for neurological treatment and investigation. This paper describes a novel system capable of achieving both stimulation and imaging while also ameliorating the shortcomings of legacy systems. Both these functions require multiple independently controlled electrodes distributed on the scalp and have complimentary functional requirements, therefore minimal additional resources are required to achieve both goals. Meeting these requirements also result in the ability to improve on legacy modalities. The system exceeds all appropriate safety requirements and is implemented with a modular architecture enabling cascading of the hardware such that the system capability and cost can be scaled according to the requirements of the application. While resource constraints precluded meeting critical functional requirements, tests and simulation of the subsystems proved the concept justifying further development.