Source reconstruction of clinical resting-state EEG reveals differences in power and functional connectivity in children with developmental dyslexia

Developmental dyslexia is a neurodevelopmental disorder characterized by significant difficulties in reading and spelling. Despite lacking routine neuroimaging markers for dyslexia, recent resting-state electroencephalography (EEG) studies have detected atypical functional connectivity (FC) at the sensor-level in children with dyslexia compared to controls. It remains unclear if routine clinical resting-state EEG can be used to detect source-level differences between children with dyslexia and controls. Using retrospective data, we investigated 70 children with dyslexia and 50 typically developing controls. We analyzed 50 s of awake resting-state routine clinical EEG, calculating power and two FC metrics after source-reconstruction. Additionally, correlations between power or FC and IQ, reading, and spelling performance were analyzed. Children with dyslexia had a decrease in theta FC in left temporo-parieto-occipital regions and an increase in alpha FC in left fronto-temporo-parietal regions. Decreased theta FC was observed for right parieto-occipital regions and an increase of alpha FC in right inferior fronto-temporal regions. Furthermore, children with dyslexia demonstrated lower power in delta and theta within the left parieto-occipital regions. No significant correlations were found between the EEG metrics and cognitive performance scores. Nevertheless, our findings contribute evidence of neurophysiological abnormalities at rest in regions relevant for visual attention and orthographic processing in dyslexia, reinforcing the possible role of oscillatory dynamics in reading and spelling development, and suggest the feasibility of source-reconstructed clinical routine EEG data to inform clinicians about oscillatory alterations in children with dyslexia.