Atypical delta-band phase consistency and atypical preferred phase in children with dyslexia during neural entrainment to rhythmic audio-visual speech

Atypical beta-band effects in children with dyslexia in response to rhythmic audio-visual speech

“…We thus also computed delta-beta PAC, beta power and angular velocity in the beta band for our children. In the delta band analyses conducted with the same children, Keshavarzi et al (2022a) reported a significantly greater angular velocity in children with dyslexia compared to control children over a time interval of -130 ms to 0 ms. This was taken to indicate that pre-stimulus delta phase was different in the two groups.…”

“…Thirty children with developmental dyslexia (mean age = 110.7 months; SD = 5.6 months) and twenty-one typically developing children (mean age = 109.3 months; SD = 5.4 months) took part in the EEG study. The children were identified as dyslexic or typically-developing based on standardized reading, spelling and phonological awareness tests administered in 2018 (please see Keshavarzi et al, 2022a, for full details). They were assessed using the British Ability Scales standardized tests of reading and spelling (Elliott et al, 1996), the Test of Word Reading Efficiency word and nonword scales (TOWRE, Torgesen et al, 1999), and the rhyming subtest of the Phonological Assessment Battery (PhAB, Frederickson et al, 1997).…”

“…EEG studies assessing speech encoding mechanisms by using linear methods for measuring neural encoding such as temporal response functions (TRFs) suggest that children with dyslexia show atypical neural encoding of continuous speech in the delta band (Power et al, 2016;Di Liberto et al, 2018;Keshavarzi et al, 2022b). Potential differences between children with and without dyslexia in the neural phase of oscillation for delta, theta and alpha bands have been assessed by utilising rhythmic speech paradigms (such as repetition of the syllable 'ba' at 2 Hz; Power et al, 2012Power et al, , 2013Keshavarzi et al, 2022a). These latter EEG studies suggest that one core neural problem during speech processing relates to inaccurate phase synchronisation of the cortical networks that respond to delta-band AM information in the speech signal (Goswami, 2022, for a recent review).…”

“…Phase entrainment in the beta band has yet to be explored in children with dyslexia in a beat-based task. Accordingly, here we re-analyse the EEG data reported by Keshavarzi et al (2022a), which investigated the delta, theta and alpha bands, this time focusing on the beta band.…”

“…The EEG was recorded while children aged 9 years with and without dyslexia listened to the speech syllable "ba" presented rhythmically at a rate of 2 Hz. Given that the participating children with dyslexia had already shown less consistent phase entrainment in the delta band (Keshavarzi et al, 2022a) and given that delta phase couples with beta amplitude via delta-beta PAC (see also Arnal et al, 2014), group differences (in terms of phase entrainment, angular velocity, and beta power) in the beta band might be expected. We thus also computed delta-beta PAC, beta power and angular velocity in the beta band for our children.…”