Detection of event related optical signal (EROS) in episodic memory retrieval task using ICA-based Kalman filter

We investigate the noise reduction performance for event related optical signal (EROS) measured from 5-channel near-infrared spectroscopy to reduce noise by using grand average and independent component analysis (ICA)-based Kalman filter. Episodic memory retrieval task was performed and expected to show brain activity around 500 ms from right prefrontal cortex. We verified that positive deviation in response to old word occurred around 500 ms using grand average for three subjects. After applying ICA-based Kalman filter on data from each subject, the clear positive deviation was shown graphically. Also, the ratio of positively deviated epoch in response to old word increased by 14 % after ICA-based Kalman filtering.