Change detection to tone pairs during the first year of life – Predictive longitudinal relationships for EEG-based source and time-frequency measures

Abstract

Brain responses related to auditory processing show large changes throughout infancy and childhood with some evidence that the two hemispheres might mature at different rates. Differing rates of hemispheric maturation could be linked to the proposed functional specialization of the hemispheres in which the left auditory cortex engages in analysis of precise timing information whereas the right auditory cortex focuses on analysis of sound frequency. Here the auditory change detection process for rapidly presented tone-pairs was examined in a longitudinal sample of infants at the age of 6 and 12 months using EEG. The ERP response related to change detection of a frequency contrast, its estimated source strength in the auditory areas, as well as time-frequency indices showed developmental effects. ERP amplitudes, source strength, spectral power and inter-trial phase locking decreased across age. A differential lateralization pattern emerged between 6 and 12 months as shown by inter-trial phase locking at 2-3 Hz; specifically, a larger developmental change was observed in the right as compared to the left hemisphere. Predictive relationships for the change in source strength from 6 months to 12 months were found. Six-month predictors were source strength and phase locking values at low frequencies. The results show that the infant change detection response in rapidly presented tone pairs is mainly determined by low frequency power and phase-locking with a larger phaselocking response at 6 months predicting greater change at 12 months. The ability of the auditory system to respond systematically across stimuli is suggested as a marker of maturational change that leads to more automatic and fine-tuned cortical responses.

Experience-dependent effects of passive auditory exposure in infants impact theta phase synchrony and predict later language

“…Methods for the auditory exposure paradigm, EEG–ERP recordings, source localization, and electrophysiological and statistical analyses used in this study closely follow those reported in previous publications from the Infancy Studies Laboratory as the same techniques, paradigms, and equipment are in use across studies ( Hämäläinen et al. 2011 , 2019 ; Ortiz-Mantilla et al. 2012 , 2013 , 2016 , 2019 , 2022 ; Musacchia et al.…”

Neural detection of changes in amplitude rise time in infancy

“…As rise time is a dynamic measure based on changes reflecting the shape of the sound pressure wave, it cannot be compared in a simple way to other measures in the infant literature used to index temporal processing, such as duration perception or gap detection. For example, infant studies related to rapid auditory processing theory as a mechanism underpinning DLD and dyslexia ( Tallal, 1980 ) have established that by 6 months of age, some infants can detect a gap between two tones that is as short as 70 ms ( Hämäläinen et al, 2019 ). Data from individual tones of this nature are not comparable to the rise time measure used here.…”

“…Infants utilise a range of acoustic cues to aid language learning. The neural literature shows that they are sensitive to rapidly-arriving pitch information ( Hämäläinen et al, 2019 ), changes in duration ( Richardson et al, 2003 ), F0 changes, and features like voice onset time ( Guttorm et al, 2005 , Guttorm et al, 2010 , Leppänen et al, 2010 , van Zuijen et al, 2013 ). The incoming stream of speech contains multiple such acoustic features that offer cues to its linguistic structure.…”

Modulation of Theta Phase Synchrony during Syllable Processing as a Function of Interactive Acoustic Experience in Infancy

“…A decrease in theta phase synchrony during processing of speech and nonspeech signals over the first year of life ( Ortiz-Mantilla et al. 2016 ; Hämäläinen et al. 2019 ) is thought to represent the more competent processing achieved with brain maturation and native language exposure.…”

“…2016 ). Over the same period, intertrial phase synchrony in the theta range also decreases when infants process tone pairs with a speech-like, 70-ms interstimulus interval (ISI) ( Hämäläinen et al. 2019 ), suggesting that neural pathways and auditory perceptual abilities strengthen over development ( Watson et al.…”