Artifacts, habituation and p300-based brain machine interfaces

We investigated to what degree the detection rate of the P300 in single trial event-related potentials is affected by short-term and long-term habituation effects, and we present an algorithm to eliminate eye-movement artifacts. Data from 26 subjects were collected using a visual oddball paradigm. P300 components were detected using a threshold algorithm operating on the delta band (0-4 Hz). Using data from four subjects, collected over a 7 to 12 week period, it was observed that the P300 amplitude tended to decrease within a session, and also between successive sessions. However, this decrease did not affect the detection rate. The eye-movement removal algorithm was tested on simulated and actual data, and resulted in a significant increase in detection rate.