Fig.2 Schematic diagram of the standing - sitting experiment
EEGs was recoded with a 32-electrode cap arranged with the international
10-20 system using the SAGA 32+ device (TMSi, Netherlands), with an
averaged reference during data recording. Four electrodes were placed
laterally to right and left eyes to record the horizontal and vertical
electrooculograms (EOG). The impedance of the electrode was set below
10KΩ and EEGs was recorded at the laptop with 1024Hz sampling rate and
the online sampling frequency band is 0-200Hz.
Besides the 32 channel EEG signal, 4 extra channel which record the IMU
data were fixed on the left upper leg and four pressure sensors (FSR
sensors) were fixed under the left foot to record the foot pressure
synchronously, which is shown in Fig.3. The preprocessing of all
subjects was completed one by one in EEGLAB. Firstly, all sessions’ data
of each subject were merged together, then the data were down sampled to
250Hz and the band-pass filtering from 0.1Hz to 48Hz was completed.
Cleanline tool was used to do the linear filtering to the signals and
the electrode positioning of all the channels was completed according to
the electrode position of SAGA system, and finally all the bad
electrodes and irrelevant channels were removed.