Obtaining single stimulus evoked potentials with wavelet denoising

We present a method for the analysis of electroencephalograms (EEG). In par ticular, small signals due to stimulation, so-called evoked potentials (EPs ), have to be detected in the background EEG. This is achieved by using a d enoising implementation based on the wavelet decomposition. One recording o f visual evoked potentials, and recordings of auditory evoked potentials fr om four subjects corresponding to different age,groups are analyzed. We fin d higher variability in older individuals. Moreover, since the EPs are iden tified at the single stimulus level (without need of ensemble averaging), t his will allow the calculation of better resolved averages. Since the metho d is parameter free (i.e. it does not need to be adapted to the particular characteristics of each recording), implementations in clinical settings ar e imaginable. (C) 2000 Elsevier Science B.V. All rights reserved.