Electroencephalographic findings in unmedicated, neurologically and intellectually intact Tourette syndrome patients.

Electroencephalograms were obtained in 30 unmedicated, neurologically and intellectually intact Tourette syndrome (TS) patients, none having a history of clinically apparent seizure disorder. Six (20%) of initial 30 EEGs were judged to be abnormal, 2 (6.6%) on account of slowing of intrinsic rhythms and/or excess of slow frequencies and 4 (13.3%) on account of epileptiform alterations. Two of the latter 4 patients continued to show similar abnormalities in EEGs done 4 and 8 months later. Five of 6 patients with abnormal EEGs had history of migraine or migraine equivalents compared to 8 of 24 with normal EEGs (chi 2 = 4.88, P less than 0.05). It is concluded that in the population of Tourette patients studied, EEG abnormalities occurred in one-fifth of all patients despite an absence of medication effect, brain damage or seizure disorder and may, in part at least, be related to associated migrainous equivalents.