Algorithm to distinguish stimulus presenting state and resting state in SSVEP with dry electrodes

Abstract

In our previous study, we performed experiments with wet gel electrodes and analyzed these SSVEPs with our detecting algorithm. However, wet gel electrodes give users discomfort.In this study, we record the SSVEP with dry electrodes.The previous algorithm cannot distinguish stimulus presentation state from rest state. We propose new algorithm to distinguish stimulus presentation state from rest state.The flickering frequency in pattern reversal stimulus is 10, 12 and 15Hz on the experiment. Each subject watch a flickering stimulus for 10 seconds. New algorithm focus on peak frequency around target SSVEP's frequency, because power spectrum has same level of each frequency in resting state. As results, we can record SSVEP with dry electrodes. The averaged detection ratio of stimulus presentation state is 83.7% and the averaged detection ratio of rest state is 89.0%.