Selective attention modulates neural envelope tracking of informationally masked speech in healthy older adults

Speech understanding in noisy situations is compromised in old age. This study investigated the energetic and informational masking components of multi-talker babble noise and their influence on neural tracking of the speech envelope in a sample of healthy older adults. Twenty-three older adults (age range 65-80 years) listened to an audiobook embedded in noise while their electroencephalogram (EEG) was recorded. Energetic masking was manipulated by varying the signal-to-noise ratio (SNR) between target speech and background talkers and informational masking was manipulated by varying the number of background talkers. Neural envelope tracking was measured by calculating temporal response functions (TRFs) between speech envelope and EEG. Number of background talkers, but not SNR modulated the amplitude of an earlier (around 50 ms time lag) and a later (around 300 ms time lag) peak in the TRFs. Selective attention, but not working memory or peripheral hearing additionally modulated the amplitude of the later TRF peak. Finally, amplitude of the later TRF peak was positively related to accuracy in the comprehension task. The results suggest that stronger envelope tracking is beneficial for speech-in-noise understanding and that selective attention is an important ability supporting speech-in-noise understanding in multi-talker scenes.