Montage-related Variability in the Characteristics of Envelope Following Responses.

Objectives The study aimed to compare two electrode montages commonly used for recording speech-evoked envelope following responses. Design Twenty-three normal-hearing adults participated in this study. EFRs were elicited by a naturally spoken, modified /susa∫i/ stimulus presented at 65 dB SPL monaurally. EFRs were recorded using two single-channel electrode montages: Cz-nape and Fz-ipsilateral mastoid, where the noninverting and inverting sites were the vertex and nape, and the high forehead and ipsilateral mastoid, respectively. Montage order was counterbalanced across participants. Results Envelope following responses amplitude and phase coherence were significantly higher overall in the Cz-nape montage with no significant differences in noise amplitude. Post hoc testing on montage effects in response amplitude and phase coherence was not significant for individual stimuli. The Cz-nape montage also resulted in a greater number of detections and analyzed using the Hotelling's T2. Conclusions Electrode montage influences the estimated characteristics of speech-evoked EFRs.