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

This study examined spontaneous activity in children aged 3-11 years with specific language impairment (SLI) using an electroencephalogram (EEG). We compared SLI-diagnosed children with a normo-development group (ND). The signal complexity, multiscale entropy (MSE) and parameterized power spectral density (FOOOF) were analyzed, decomposing the PSD into its aperiodic (AP, proportional to 1/fx) and periodic (P) components. The results showed increases in complexity across scales in both groups. Although the topographic distributions were similar, children with SLI exhibited an increased AP component over a broad frequency range (13-45 Hz) in the medial regions. The P component showed differences in brain activity according to the frequency and region. At 9-12 Hz, ND presented greater central-anterior activity, whereas, in SLI, this was seen for posterior-central. At 33-36 Hz, anterior activity was greater in SLI than in ND. At 37-45 Hz, SLI showed 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.