Abstract
In the single sweep record of ERP (event-related potential), peak latency of P300, which is one of the most prominent positive peaks in the ERP record, might fluctuate according to the recording conditions of the subject during the recording time. It is important to investigate whether the fluctuation of the peak latency (measurement fluctuation) is caused by physiological factor (physiological fluctuation) or by the noise of background EEG (noise fluctuation). In this paper, we proposed a method for extracting the physiological fluctuation of the peak latency of P300 from the measurement fluctuation. We clarified the relationship between the SN ratio of the single sweep ERP and the noise fluctuation based on the models which represented the features of the P300 and the background EEG appropriately. The noise fluctuation can be estimated by using the relationship, and the physiological fluctuation is extracted by subtracting the estimated noise fluctuation from the measurement fluctuation. In order to evaluate the proposed method, we estimated the physiological fluctuation in simulation data in which the true value of the physiological fluctuation was already known, and were able to obtain the accurate estimation value of the physiological fluctuation of the peak latency. Furthermore, the proposed method was applied to actual ERP data of eleven healthy adults, and the physiological fluctuation of the peak latency was extracted.
