Biomedical subjects
Publications and source records attributed to D G Wastell.
A linear filter, whose weights are based on the binomial coefficients, is described. It is shown that the phase distortion introduced by the filter is zero and the application of the filter to smoother EP records is illustrated.
Donchin, Tueting, Ritter, Kutas and Heffley (1975) present evidence from a principal components analysis (PCA) that the CNV and P300 are independent. This short critique points out a number of erros in their PCA and presents a reworking of their analysis. A number of further aspects of Donchin et al.'s paper are also discussed. The general value of this contribution in drawing the attention of EP researchers to potential sources of error in the application of factor analysis is emphasized.
The practical performance of the adaptive filter developed by Woody (1967) and Harris and Woody (1969) is assessed in terms of its ability to distinguish evoked responses from the background EEG. It is concluded that selection of good initial template, in this case the Averaged ER, renders iterations beyond the first doubtful validity in the majority of subjects. It is stressed that where iterations are pursued care should be taken over the choice of a suitable statistic to index the process. Finally, given the efficacy of the cavariance function in detecting the grosser features of ER morphology in individual responses, a single trial approach to the analysis of ERs is recommended.