ABSTRACT
OBJECTIVES: Tourette's Disorder (TD) is a chronic neuropsychiatric disorder characterized by multiple motor and vocal tics with onset in childhood. The aim of this study was to ascertain the increased cortical information transmission in frontal area during tic suppression in drug naive boys with TD using new nonlinear analysis of EEGs, be called Transfer Entropy (TE) which can detect the directed exchange of information between two systems. METHODS: Subjects were 11 drug naive boys with DSM-IV diagnosis of TD and 10 control boys. Clinical assessments were performed, and EEGs were recorded from 19 scalp loci of the international 10-20 systems. TE was estimated by EEG timeseries data after noise reduction. TE difference between TD and control during resting state and between tic suppression and resting state in TD were investigated. RESULTS: Elevated TE was found in extensive channels, including frontal, central and temporal channels (F7, Fz, F8,Cz, C3, P3, T3, and T4) in resting state of Tourette's disorder compared to normal controls. During tic suppression elevated TE was found in more extensive and asymmetrical channels especially prefrontal area (Fp1, Fp2, F3, Fz, F7, F8, Cz, C4, C5, T3, and T4). CONCLUSION: These findings suggest that pathogenesis of Tourette's disorder involve impaired cortical neuronal modulation in subcortical neural circuits. EEG analysis of TE may be a useful tool to investigation of cortical mechanism of psychiatric illness.