Choosing multichannel objective response detectors for multichannel auditory steady-state responses

Abstract

The assessment of evoked responses still largely relies on subjective assessment, though a number of objective response detection techniques have been proposed, which are usually based on the statistical analysis of electroencephalogram (EEG) signals. In the current work, we expand on this with an investigation of multichannel objective response detection (MORD) methods, by assessing the performance of six previously published MORD algorithms together with three new methods (named product of Local Spectral F-test, average and the product of Component Synchrony Measure). The MORD techniques were evaluated in both simulated data and in multifrequency Auditory Stead-State Responses (ASSRs) recorded from 11 normal-hearing volunteers. The performances of MORD techniques were evaluated based on detection rates and the number of false positive tests. The results demonstrate that inflated false positive rates can arise when correlation between EEG channels is not taken into account by some of the MORD methods, but the algorithms are fairly robust to low cross-channel correlations. Furthermore, two of the already established MORD techniques showed immunity to cross-channel correlation. The results showed that the sensitivity of response detection increased when more than one channel was used, and an increase of up to 16 % compared to the best single-channel method could be achieved by the newly proposed best MORD methods. MORD methods are thus a promising new tool for ASSR detection.