P300 differences exist between Tourette's syndrome with and without attention deficiency and hyperactivity disorder in children

Abstract

Objective: To study the characteristics of P300 in Tourette's syndrome (TS) with and without attention deficiency and hyperactivity disorder (ADHD). Method: Auditory evoked P300 were recorded in 19 TS only (TS–ADHD) children, 15 TS with ADHD (TS + ADHD) children and 20 unaffected control subjects, and their waveforms, amplitudes, latencies and topographies were compared at Fz, Cz, C3, C4 and Pz. Results: The TS + ADHD group showed shorter latencies than control subjects at all electrode sites (P<0.05 or 0.01), and the TS–ADHD group at CZ and PZ (P<0.05); however, there was no significant difference between control subjects and the TS–ADHD group. The TS–ADHD group showed smaller amplitudes than the control group at all electrode sites (P<0.05), and the TS + ADHD group at Cz (P<0.05); however, there were no significant differences between control subjects and the TS + ADHD group. There was no significant difference in the prevalence of abnormal waveforms between the control, TS, TS–ADHD and TS + ADHD groups, but there were significant differences in the variability of localization of P300 between the control and the TS group (P=0.003), control and TS + ADHD groups (P=0.000), and the TS–ADHD and TS + ADHD groups (P=0.039). P300 in the TS + ADHD group tended to spread out to the left and that of the TS–ADHD group tended to spread out to the right. Conclusions: P300 differences exist between TS–ADHD and TS + ADHD in children. These suggested that establishment different development defects or delay of communications between different structures rather than a delay in maturation of the structures themselves may be involved in TS + ADHD and TS–ADHD children and ADHD symptoms in TS patients are likely a trait rather than adventitious or acquired within the TS syndrome.