Brain Complexity and Parametrization of Spectral Power Density in Children with Specific Language Impairment

This study examines spontaneous activity in children aged 3-11 years with Specific Language Impairment (SLI) using electroencephalogram (EEG). We compared SLI diagnosed children with a normo-development group (ND). Signal complexity Multiscale Entropy (MSE) and parameterized Spectral Power Density (FOOOF) were analyzed, decomposing the PSD into its aperiodic (AP, proportional to 1/fx) and periodic (P) components. The results show increases in complexity across scales in both groups. Although topographic distributions were similar, children with SLI exhibited higher lateralized exponent parameter values in both hemispheres, along with an increased AP component over a broad frequency range (13–45 Hz) in medial regions. The P component shows differences in brain activity according to frequency and region. At 9–12 Hz, ND presents greater central-anterior activity, whereas in SLI, it is posterior-central. At 33–36 Hz, anterior activity is greater in SLI than in ND. At 37–45 Hz, SLI shows greater activity than ND, with a specific increase in the left, medial, and right regions at 41–45 Hz. These findings suggest alterations in the excitatory-inhibitory balance and impaired intra and interhemispheric connectivity, indicating difficulties in neuronal modulation possibly associated with the cognitive and linguistic characteristics of SLI.