Digital filtering of auditory evoked potentials

Effects of Artifact Rejection and Bayesian Weighting on the Auditory Brainstem Response During Quiet and Active Behavioral Conditions

Purpose

To evaluate the effects of 2 noise reduction techniques on the auditory brainstem response (ABR).

Method

ABRs of 20 normal hearing adults were recorded during quiet and active behavioral conditions using 2 stimulus intensity levels. Wave V amplitudes and residual noise root-mean-square values were measured following the offline application of artifact rejection and Bayesian weighting. Repeated measures analysis of variance and Bonferroni adjusted pairwise t tests were utilized to evaluate significant main effects and interactions between the 2 noise reduction techniques.

Results

ABRs recorded during the quiet behavioral condition resulted in minimal differences in wave V amplitude and noise reduction improvement, suggesting that the 2 techniques were equally effective under ideal recording situations. During the active behavioral condition, however, the techniques differed significantly in the ability to preserve the evoked potential and reduce noise. Consequently, strict artifact rejection levels resulted in an inherent underestimation of wave V amplitudes when compared with the Bayesian approach.

Conclusion

Artifact rejection had a detrimental effect on waveform morphology of the ABR. This could lead to difficulty in ABR interpretation when patients are active and ultimately result in diagnostic errors.