We appreciate the comments of Dr Barabas and co-workers and are pleased to learn that their data support our finding of a relatively low incidence of EEG abnormalities in patients with TS. Their slightly higher incidence of EEG abnormalities may in part relate to the younger age of their study sample (mean age, 10.3 years in their series and 14.8 years in ours), It is curious, however, that the incidence of migraine among their patients with TS is so high, a finding not confirmed in our population. In addition, the authors state that these patients with migraine have a lower incidence of EEG abnormalities, a finding contrary to several previous studies reporting a higher incidence of minor EEG abnormalities in such patients El, 2 , 31. We therefore wonder if their finding of fewer EEG abnormalities among patients with TS and migraine is statistically meaningful, especially in view of the variety and nonspecific nature of the EEG abnormalities they describe. Furthermore, it is not clear whether the EEG ever made a difference in either diagnosing or managing their patients with TS.
TS remains an incompletely understood neurological disorder with varied manifestations and associated difficulties. Major advances in classification of patients with TS would be welcome, but our own studies suggest that standard EEG recordings are unlikely to be useful for this purpose. We await rhe publication of the study by Dr Barabas and colleagues with interest, but we remain skeptical. It continues to be our opinion that there is no diagnostic or therapeutic value in routine EEG studies in the evaluation of patients with established TS.