Validation of a Wireless and Portable EEG Acquisition System with Dry Electrodes

The Electroencephalogram (EEG) is the non-invasive record of electrical cerebral activity. It is used commonly in sleep studies and in the diagnosis of brain diseases and injuries. In order to reduce noise in the acquisition process and enable new EEG applications such as BCI and home polysomnography studies, we carry out the design and manufacture of a portable wireless system for acquisition of EEG signals. In this paper, we carried out the validation of the system designed by comparing signals acquired with commercial EEG equipment from the AKONIC company. Different EEG recordings were obtained in 4 healthy adult subjects using standard Ag/AgCl cup electrodes and dry electrodes TDE-200 from Florida Research Instruments. Also, we performed the analysis of the acquired signals in eyes-closed and eyes-open resting condition. We conclude that the designed system has low noise levels (0.147 μVRMS and 0.984 μVp-p) and a signal quality comparable to that of commercial equipment, which allows its use in research tasks and portable studies. On the other hand, we observe that the quality of the signal obtained with the dry electrodes is worse, due to the high skin-electrode impedance, but even so it is good enough to detect the eyes-closed and eyes-open resting condition, allowing a more comfortable use of the system.