Time-efficient Methodology for Robustly Assessing Speech-related Mismatch Responses in Adults and Infants.

The mismatch response (MMR) is a critical neural indicator of the discrimination of speech contrasts. Previous research has demonstrated that language experience can affect MMRs: speech contrasts in one's native language differ from nonnative speech contrasts. This effect is observed as early as 11-12 months, but not at 6-7 months, reflective of early learning of speech sounds. Yet, many challenges remain when using MMRs to study speech learning in infants, including prolonged recording time, inefficient use of data, and a lack of reconciliation of MMR recorded using different technologies (i.e., EEG vs. magnetoencephalography [MEG]). Using an improved recording paradigm and analysis approach, the current study addressed these challenges by examining (1) whether MEG-MMR is linked to the well-established EEG-MMR in the same adults and (2) whether our methods capture the difference in MEG-MMR between native and nonnative speech contrasts in adults and (3) in older infants. Results from 18 adults with simultaneous M/EEG demonstrated a high correlation between the MEG-MMR and the EEG-MMR. Additionally, MEG-MMRs to native speech contrasts were different from ones to nonnative speech contrasts, replicating spatiotemporal patterns documented in the existing literature. Finally, we replicated this effect in the MEG-MMR in 14 infants aged between 9 and 14 months using the same methods. These findings validate our new methodologies with less than 15 mins of recording time for acquiring and analyzing speech-related MMRs across ages, paving the way for studying early language development, and improving early detection of language-related disorders.