The impact of reading acquisition on audiovisual processing

The impact of reading acquisition on audiovisual processing

First Author: Sendy Caffarra -- Stanford University
Additional authors/chairs: 
Jason Yeatman; Mikel Lizarazu; Nicola Molinaro; Manuel Carreiras
Keywords: Reading acquisition, Syllable, visual and auditory temporal processing, MEG Neuroimaging, early childhood (age 4 - 6)
Abstract / Summary: 

Purpose: This MEG study tested whether and how reading acquisition influences the way our brain treats audiovisual information. To this aim, we characterized the temporal and spatial neural correlates of cross-modal syllable integration while children learned to read.

Method: In a cross-sectional (20 five-year-old pre-readers and 22 seven-year-old readers) and a longitudinal (15 children who participated at ages five and seven) MEG study, participants were presented with 120 Spanish written syllables. After one second of visual presentation, a spoken Spanish syllable was also presented. The spoken syllable could be either congruent or incongruent with the ongoing visual presentation (60 items/condition). Additional non-linguistic catch trials (i.e., animal-related pictures and sounds) were added to make sure participants were paying attention to stimuli presented in both modalities. Evoked related fields (ERFs) were calculated and time-locked to the auditory presentation onset. ERF congruence effects were identified using cluster-based permutations and were source reconstructed using beamforming.

Results: In both cross-sectional and longitudinal studies, readers (but not pre-readers) showed an ERF congruence effect 400 ms after the spoken syllable onset, with suppressed amplitude in the congruent condition. The size of this effect correlated with children’s reading skills after controlling for age, non-verbal IQ, and vocabulary size. In both studies, this effect was localized in the left superior and medial temporal cortex.

Conclusions: While learning to read, children progressively set up audio-visual associations, which can be detected within the first 400 ms of a bimodal presentation and recruit the superior portions of the left temporal cortex.