Developmental aspects of language lateralization in delta, theta, alpha and beta EEG bands

This study aimed to clarify the functional role of several EEG bands across age by analyzing language hemispheric lateralization in three linguistic tasks. Twenty-eight children, 22 young adults and 20 middle-aged participants were administered the same sample of written words and normalized amplitudes of δ, ϑ, α and β bands were analyzed. Only young adults showed rightwards lateralization in δ frequency band. Task-dependent right-lateralization marked adults’ ϑ and α distributions, whereas only linguistic vs. non-linguistic differences were found in children. Concerning the high-beta band, all groups showed left-lateralized linguistic effects. In adults slow rhythms represent indices of active inhibition of task-irrelevant regions, but in children they marked incomplete automated linguistic processing. The high-beta band revealed task-relevant left hemisphere linguistic activity in all groups, therefore representing the most reliable EEG marker of language hemispheric dominance in children and adults.

The high-beta band (β2) was, in a linguistic paradigm, the only rhythm which showed the same coherent left hemispheric pattern across all age groups, including children typically not yet fully competent in reading, with greater amplitude to linguistic tasks (i.e., the Phonological and the Semantic ones) in left frontal sites.Figure optionsDownload as PowerPoint slideResearch highlights▶ This study aimed to investigate language lateralization across ages by measuring several EEG bands. ▶ Three groups of children aged 10, young adults and middle-aged participants were tested in three linguistic tasks, Semantic, Phonological and Orthographic, while EEG was recorded from 38 scalp locations. ▶ Language lateralization and the functional role of EEG bands were different in the three age groups in the low frequency bands delta, theta and alpha. ▶ the high-beta band was left lateralized, especially in frontal sites, in all groups, a result which points to high-beta band as the most effective EEG marker of language lateralization across all ages.