Infant low-frequency EEG cortical power, cortical tracking and phase-amplitude coupling predicts language a year later.

Abstract

Cortical signals have been shown to track acoustic and linguistic properties of continual speech. This phenomenon has been measured across the lifespan, reflecting speech understanding as well as cognitive functions such as attention and prediction. Furthermore, atypical low-frequency cortical tracking of speech is found in children with phonological difficulties (developmental dyslexia). Accordingly, low-frequency cortical signals, especially in the delta and theta ranges, may play a critical role in language acquisition. A recent investigation Attaheri et al., 2022 (1) probed cortical tracking mechanisms in infants aged 4, 7 and 11 months as they listened to sung speech. Results from temporal response functions (TRF), phase-amplitude coupling (PAC) and dynamic theta-delta power (PSD) analyses indicated speech envelope tracking and stimulus related power (PSD) via the delta & theta neural signals. Furthermore, delta and theta driven PAC was found at all ages with gamma amplitudes displaying a stronger PAC to low frequency phases than beta. The present study tests whether those previous findings replicate in the second half of the same cohort (first half: N=61, (1); second half: N=61). In addition to demonstrating good replication, we investigate whether cortical tracking in the first year of life predicts later language acquisition for the full infant cohort (122 infants recruited, 113, retained). Increased delta cortical tracking and theta-gamma PAC were related to better language outcomes using both infant-led and parent-estimated measures. By contrast, increased ~4Hz PSD power and a greater theta/delta power ratio related to decreased parent-estimated language outcomes. The data are interpreted within a "Temporal Sampling" framework for developmental language trajectories.

Neural responses to natural and enhanced speech edges in children with and without dyslexia

“…In a related investigation of the TSF in infants, a higher thetadelta power ratio when listening to natural speech was found to predict slower language acquisition by infants (Attaheri et al, 2022, preprint). In their study of over 100 infants for whom EEG was recorded when listening to nursery rhymes at 4, 7 and 11 months, Attaheri et al (2022) found that a greater theta-delta power ratio at 11 months was associated with poorer vocabulary outcomes at 24 months. Interestingly, the large increase in spectral power in the delta band found in the current study accompanied by the smaller reduction in the theta band reduces the theta-delta power ratio for children with dyslexia.…”

“…Lastly, we estimated the theta-delta ratio by dividing the averaged band power in the theta band by the averaged band power in the delta band, per epoch. This was of interest because recent dyslexia modelling data (Araújo et al, 2022) and infant language acquisition data (Attaheri et al, 2022) from our group has indicated that worse language outcomes are associated with a higher theta-delta ratio.…”

Cortical tracking of visual rhythmic speech by 5‐ and 8‐month‐old infants: Individual differences in phase angle relate to language outcomes up to 2 years

“…Like other neural analyses within the Cambridge UK BabyRhythm project, we take a whole‐head approach to relative power and to ITC (Attaheri et al., 2022; Ní Choisdealbha et al., 2022). The assumption is that, if tracking is taking place, the phenomenon should be robust enough to pick up even when averaging across the scalp.…”

“…The language measures were decided a priori (Rocha et al., 2022 preprint, for rationale) and were grouped into parent‐reported standardised measures and infant‐led experimental measures encompassing phonology, communicative gesture, and vocabulary. The same measures were used for all Cambridge UK BabyRhythm papers using neural predictors to estimate language outcomes (Attaheri et al., 2022 preprint; Ní Choisdealbha et al., 2023). The parent‐reported measures were receptive and productive vocabulary scores in the Lincoln CDI (Meints et al., 2017) at 24 months.…”

Sing to me, baby: Infants show neural tracking and rhythmic movements to live and dynamic maternal singing

“…We also wanted to investigate the three-way relationship between neural tracking, rhythmic movements to music, and language development. Recent evidence suggests that neural tracking of nursery rhymes is predictive of infants’ later language outcomes (Attaheri, Choisdealbha, Rocha, et al, 2022; Menn, Ward, et al, 2022). Brandt and colleagues (2012) propose that the musical aspects of language (i.e., prosody, rhythm, timbral contrast) scaffold the later development of semantic and syntactic aspects of language.…”