A Multi-Electrode Transcranial Direct Current Stimulator (ME-tDCS): Design considerations and safety aspects

Transcranial direct current stimulation (tDCS), a promising neuromodulation technique, is being used to treat a myriad of psychiatric conditions, movement disorders, aphasia, Parkinsonism and so on. It is also being used by the healthy population for cognitive enhancement. The device, though not very complex in design, has to take into consideration a large number of precautionary factors and should only be used by trained medical personnel. Most approved high definition transcranial direct current stimulator (HD-tDCS) devices are very expensive and are not affordable by most hospitals in middle to low income countries. The objective of this work was to design a multi-electrode transcranial direct current stimulator (ME-tDCS), whose performance is in par with currently available approved devices. The ME-tDCS integrates both tDCS and 4x1 HD-tDCS into a single cost-effective unit. It features 4 channels and allows for switching between tDCS and 4x1 HD-tDCS modes. The device was tested to ensure both effectiveness and safety for scalp resistances between 2 kΩ and 8 kΩ, well within the anticipated range of scalp resistance. This provides a safe and cost-effective solution for tDCS/HD-tDCS applications in small clinics. This article describes the design and safety aspects of the ME-tDCS.