Estimation of evoked potentials using segment latency corrected average
Y.H. Lee, D.H. Lee, Yunyeong Kim, D.S. Lee, S.I. Kim · 2002
A method for the estimation of event related evoked potential (EREP) with time-varying properties is presented. The procedure consists of three steps. First, as a preprocessor, it uses an adaptive filter to reduce the effects of artifacts and to get an improved response. Then, the filtered response is divided into individual segments, and the latency shifts of each segment are detected by cross-correlation between the filtered response and a template formed by the average of the previous obtained responses within interval of individual segments. Finally, after the detected latency shifts, the responses of each segment are corrected as much as the latency shifts, respectively. The corrected segments are grouped, and the whole corrected ERP is obtained by averaging. In this procedure, the results of the conventional methods including simple average, Woody's method, and peak component latency corrected average (LCA) are obtained, their results compared with the present method for evaluating performance. From the results, the presented method is confirmed that it reflects the latency changes of fundamental peaks and gets the improved ERP.