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PubMed2005

Optimized brainstem auditory evoked potentials estimation using simulated annealing.

In this paper, we use a new approach based on Simulated Annealing for estimating the BAEPs (brainstem auditory evoked potentials). Each BAEP is obtained through a hundred of responses to stimulations. In case of endocochlear pathologies, it has been assumed that these signals could be randomly delayed from a response to another one. In such cases, the application of the averaging method systematically leads to "smoothed" BAEPs, thus complicating both identification and interpretation operations. The method presented in this paper consists in minimizing a non linear criterion in order to obtain an alignment of the various responses, before averaging them. Simulated and experimental results are presented, and compared to those produced by the classical method.

Brain Stem↗

PubMedDate not supplied

BAEP dynamic estimation in case of endocochlear pathologies using a time delay correction method.

Extraction of Brainstem Auditory Evoked Potentials (BAEPs) from the electroencephalogram (EEG) is generally difficult when both BAEP and EEG are non-stationary. In this paper we focus on the problem of BAEP non-stationarities, in particular those observed in some endocochlear pathologies assumed causing random delays of BAEPs due to an abnormal behaviour of the cochlea. The technique developed in this paper, called the Time Delay Correction (TDC) method, allows us to estimate the averaged BAEP by an optimal alignment of responses based on a correlation criterion. We demonstrate that the TDC method avoids wave smoothness, generally produced with the classical ensemble averaging method, especially in the case when the hypothesis of the time delay non-stationarity is verified. The TDC method is performed using simulated annealing (SA) algorithm, since the criterion to be optimized is nonlinear. Real signals recorded from pathological subjects are used to validate the model of non-stationarity.

Adult↗