Biology subjects

Parvez, L.

Publications and source records attributed to Parvez, L..

4 recordsLinked to original sources

bioRxiv2025

Neural processing of natural speech by children with developmental language disorder (DLD): EEG speech decoding, power and classifier investigations

The sensory/neural Temporal Sampling (TS) theory of developmental language disorder (DLD) is based on the sensory and linguistic impairments in rhythm processing that are found in children with both developmental dyslexia (DD) and DLD. These sensory/linguistic impairments include decreased sensitivity to amplitude rise times (ARTs, the sensory triggers related to automatic cortical speech tracking), syllable stress patterns and speech rhythm. At the neural level TS theory predicts impairments in the cortical tracking of different rates of amplitude modulation (AM) in the speech signal <10Hz. To date, the accuracy of low-frequency cortical tracking in natural continuous speech has not been measured in children with DLD. Here, EEG was recorded during story listening from children with and without DLD aged around 9 years, and decoding analyses in the delta, theta and alpha (control) bands were carried out. EEG power was computed in the delta, theta and gamma bands, and phase-amplitude coupling and phase-phase coupling (PAC, PPC) were also computed between bands. Whole-brain analyses showed that the accuracy of low-frequency decoding (delta, theta) did not differ between groups. However, region-specific analyses revealed significantly reduced delta-band speech tracking in the right temporal cortex in the children with DLD. PAC and PPC dynamics did not differ between groups. The data suggest that low-frequency cortical tracking impairments in DLD may be spatially constrained to the right hemisphere rather than globally present as in DD. The data are discussed using TS theory. HighlightsO_LICortical tracking of natural speech is measured in children with and without DLD C_LIO_LIDelta-band tracking is impaired in right temporal regions in children with DLD C_LIO_LICross-frequency coupling dynamics (PAC, PPC) did not differ between groups C_LI

neuroscience↗

bioRxiv2024

Investigating the 'Atypical Rhythm Risk' hypothesis in children with developmental language disorder using an EEG rhythmic speech paradigm

Sensitivity to rhythmic and prosodic cues in speech has been described as a precursor of language acquisition. Consequently, atypical rhythmic processing during infancy and early childhood has been considered a risk factor for developmental language disorders. Despite many behavioural studies, the neural processing of rhythmic speech has not yet been explored in children with developmental language disorder (DLD). Here we utilise EEG to investigate the neural processing of rhythmic speech by 9-year-old children with and without DLD. In the current study, we investigate phase entrainment, angular velocity, power, event related potentials (ERPs), phase-amplitude coupling (PAC) and phase-phase coupling (PPC), at three frequency bands selected on the basis of the prior literature, delta, theta and low gamma. We predicted a different phase of entrainment in the delta band in children with DLD, and also greater theta power, atypical cross-frequency coupling and possibly atypical gamma-band responses. Contrary to prediction, children with DLD demonstrated significant and equivalent phase entrainment in the delta and theta bands to control children. However, only the control children showed significant phase entrainment in the low gamma band. The children with DLD also exhibited significantly more theta and low gamma power compared to the control children, and there was a significant gamma-band difference in angular velocity between the two groups. Finally, group resultant phase analyses showed that low-frequency phase (delta and theta) affected gamma oscillations differently by group. These EEG data show important differences between children with and without DLD in the neural mechanisms underpinning the processing of rhythmic speech. The findings are discussed in terms of auditory theories of DLD, particularly Temporal Sampling theory.

neuroscience↗

bioRxiv2023

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

Children with dyslexia are known to show impairments in perceiving speech rhythm, which impact their phonological development. Neural rhythmic speech studies have reported atypical delta phase in children with dyslexia, but beta band effects have not yet been studied. It is known that delta phase modulates the amplitude of the beta band response during rhythmic tasks via delta-beta phase-amplitude coupling (PAC). Accordingly, the atypical delta band effects reported for children with dyslexia may imply related atypical beta band effects. Here we analyse EEG data collected during a rhythmic speech paradigm from 51 children (21 typically-developing; 30 with dyslexia) who attended to a talking head repeating "ba" at 2Hz. Phase entrainment in the beta band, angular velocity in the beta band, power responses in the beta band and delta-beta PAC were assessed for each child and each group. Phase entrainment in the beta band was only significant for children without dyslexia. Children with dyslexia did not exhibit any phase consistency, and beta-band angular velocity was significantly faster compared to control children. Power in the beta band was significantly greater in the children with dyslexia. Delta-beta PAC was significant in both groups. The data are interpreted with respect to temporal sampling theory.

neuroscience↗

bioRxiv2022

Decoding of Speech Information using EEG in Children with Dyslexia: Less Accurate Low-Frequency Representations of Speech, Not "Noisy" Representations

The amplitude envelope of speech carries crucial low-frequency acoustic information that assists linguistic decoding. The sensory-neural Temporal Sampling (TS) theory of developmental dyslexia proposes atypical encoding of speech envelope information <10 Hz, leading to atypical phonological representations. Here a backward linear TRF model and story listening were employed to estimate the speech information encoded in the electroencephalogram in the canonical delta, theta and alpha bands by 9-year-old children with and without dyslexia. TRF decoding accuracy provided an estimate of how faithfully the childrens brains encoded low-frequency envelope information. Between-group analyses showed that the children with dyslexia exhibited impaired reconstruction of speech information in the delta band. However, when the quality of speech encoding for each child was estimated using child-by-child decoding models, then the dyslexic children did not differ from controls. This suggests that children with dyslexia encode neither "noisy" nor "normal" representations of the speech signal, but different representations.

neuroscience↗