Late components of the auditory evoked potentials in Gilles de la Tourette syndrome.

Late components (N1, P2, N2, P3) of the event-related potential (ERP) elicited by simple auditory discrimination tasks were investigated in 6 patients with Gilles de la Tourette syndrome. The ERP's were registrated in the patients before and during drug treatment as well as in 16 healthy controls. It appeared that in Tourette syndrome the N2 and P2 waveforms (target response) at Cz and Pz were remarkably less well identifiable. The results did not reveal P3 abnormalities in the patients. However, the patients demonstrated definite changes in the N1 and P2 components as compared to the controls. The N1 amplitudes were decreased in the patients. During drug treatment the N1 amplitudes increased although they remained smaller than in the controls. It is concluded that Tourette patients have no abnormalities in early and late components, but that specifically the components between 90-280 ms are affected. These abnormalities may reflect specific attention deficits which often occur in Tourette syndrome.