# Neural tracking of continuous speech reveals enhanced late responses to degraded speech

## TL;DR

The study shows that degraded speech activates delayed brain responses in language areas, helping us understand how the brain compensates for difficult listening conditions.

## Contribution

The study introduces a novel finding of a delayed P400TRF component linked to language areas during degraded speech comprehension.

## Key findings

- Clean speech shows stronger and more precise early neural responses (N1TRF and P2TRF).
- Degraded speech triggers a delayed P400TRF response from language-related brain regions.

## Abstract

Comprehending degraded speech demands greater cognitive effort. While previous studies have identified the neural pathways involved in processing degraded speech signals, the temporal dynamics of these neural networks remain unclear.

This study investigated the time course of neural responses to clean and degraded (i.e., noise-vocoded) speech signals using temporal response functions (TRFs).

Our findings reveal that early TRF components (N1TRF and P2TRF) exhibited greater amplitude and temporal precision for clean speech. In contrast, degraded speech elicited additional cortical responses with a longer delay, designated as P400TRF. Subsequent source localization analyses showed that the P400TRF component originates from language processing areas within the temporal and frontal lobes.

These findings highlight the role of delayed neural mechanisms in maintaining speech comprehension when intelligibility is compromised, offering novel insights that broaden our understanding of auditory cortical processing under challenging listening conditions.