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

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.