Application of digital filtering and automatic peak detection to brain stem auditory evoked potential

Abstract

A method to establish optimal parameters for automatic analysis of the BAEP was proposed. Spectral analysis of a set of BAEP trial averages yields criteria for the selection of the optimal bandwidth for digital filtering, establishes a lower limit for the number of averaged responses required for accurate determination of BAEP wave shape and permits accurate estimation of the amplitude and latency of BAEP peaks. Estimation of phase variance proved to be an effective procedure for selection of the optimal frequency band for automatic peak detection. Complete representation of the BAEP should include unfiltered and digitally filtered signals, an accuracy estimate of the filtered signal, and computer peak detection. High stability of detected peak latency values, as a result of using a digital filter with optimal parameters, will allow a reduction in the number of responses which must be averaged to obtain an accurate estimate of BAEP morphology. This should be of particular value where closely spaced serial observations are desirable, as in intra-operative monitoring. Procedures analogous to those described herein should permit reduction of the sample size required for accurate estimation of the morphology of far-field somatosensory evoked potentials, and for cortical potentials evoked by any stimulus modality. The consequent increase in the speed with which reliable measurements can be obtained can be expected to increase the practical application of all evoked potential techniques.