582 Inter and Intrahemispheric Eeg Nonlinear Synchronization in Children with Attention Deficit Hyperactivity Disorder

Abstract

Aims: To assess inter and intra EEG functional connectivity of children with Attention Deficit Hyperactivity Disorder (ADHD) of mixed type through nonlinear EEG synchronization measures. Methods: Signals: digitised monopolar EEGs (sampling rate: 256 Hz) from an ADHA group (12 males, 6-10 years) and a control (CONT) group (11 males, 6-10 years). Recording electrodes: Fp1/C3/ T3/O1 (reference A2) and Fp2/C4/T4/O2 (reference A1). Pairwise interdependence between electrodes was assessed through a nonlinear index (L) for the assessment of generalized synchronization between the amplitudes of the signals. Also, properly generated surrogate data were used to test the significance of the interdependences. Intra cortical connectivity for the left and right hemisphere was obtained averaging all possible intrahemispheric pairs L values. Interhemispheric connectivity was computed averaging the homotopic hemisphere electrodes pairs L values. Conditions considered were: basal eyes-open and basal eyes-closed. ANOVA test for repeated measures and post-hot Bonferroni test was used for between-group comparisons. Results: Intrahemispheric interdependences did not shown between-groups differences in any experimental conditions considered. Nevertheless, interhemispheric interdependence was greater (P< 0.001) for the ADHA group in both experimental conditions considered without significant differences between them. Conclusions: ADHD children of mixed type show increased generalized nonlinear interhemispheric synchronization. Nonlinear EEG interhemispheric synchronization measures might be considered as clinical diagnostic help for ADHD children