WEIGHTED AVERAGING OF EVOKED-POTENTIALS

Weighted averages of brain evoked potentials (EP's) are obtained by we ighting each single EP sweep prior to averaging. These weights are sho wn to maximize the signal-to-noise ratio (SNR) of the resulting averag e if they satisfy a generalized eigenvalue problem involving the corre lation matrices of the underlying signal and noise components. The sig nal and noise correlation matrices are difficult to estimate and the s olution of the generalized eigenvalue problem is often computationally impractical for real-time processing. Correspondingly, a number of si mplifying assumptions about the signal and noise correlation matrices are made which allow an efficient method of approximating the maximum SNR weights. Experimental results are given using actual auditory EP d ata which demonstrate that the resulting weighted average has estimate d SNR's that are up to 21% greater than the conventional ensemble aver age SNR.