A Frontal SSVEP-Based Brain Computer Interface

• Main Authors: Yu-Chen Huang, 黃昱禎
• Other Authors: 李柏磊
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/2p3637

碩士 === 國立中央大學 === 電機工程學系 === 103 === This study aim to develop a new brain computer interface (BCI), which is based on frontal Steady State Visual Evoked Potential (SSVEP) evoked by phase-tagged flashes in four light emitting diodes (LEDs).Traditional SSVEP-based BCI usually place electrodes on the scalp overlying occipital region. However, scalp around occipital area is usually covered with hair which requires longer setup time than non-hair bearing area and the contact impedance increases with the experiment time. Therefore, in order to achieve a SSVEP-based BCI for convenient use, the measurement of EEG electrode was moved to Fpz position in this study, referring to international EEG 10-20 system. Though several studies have been discussed about the relation between frontal SSVEP and cognitive functions, to our understanding, rare literatures were found in BCI applications. To investigate the possibility of frontal SSVEP in BCI use, we have first investigated the frequency-preference characteristics of frontal SSVEP and then evaluate the feasible flash number and flashing frequencies for BCI control. We found frontal SSVEP is more easily influenced by motion artifacts, such as eye blinks and eye movements. With proper rejection of artifact-contaminated SSVEP epochs, the frontal SSVEP can be stably obtained through band-pass filtering and epoch-averaging process. In our study, six subjects were recruited to sequentially input a command sequence, consisting of a sequence of four numbers, repeated twice. The accuracy and information transfer rate (mean ± SD) over the six subjects were 91.00 ± 7.68% and 12.36 ± 3.06 bits/min, respectively.