Evidence for changed recognition of emotionally charged words in patients with Gilles de la Tourette syndrome and obsessive compulsive disorder

Patients with Gilles de la Tourelle syndrome (TS) frequenlly show obsessions and compulsions. Palhophysiologically, TS has been linked to abnormalilies of the basal ganglia and forebrain which are related to emotional processes. Because recordings of event-related potentials (ERPs) have shown that the emotional content of words interacts with the subjects' ability to recognise repeated words we hypothesised that patients who were diagnosed to have TS and obsessive compulsive disorder (OCD) utilised a changed cognitive process for the recognition of emotional words. ERPs were recorded while 12 patients and matched control subjects viewed a series of emotionally neutral, negative, and positive words. These were repeated after some intervening items with the task being to discriminate between new words and repeated words. In both groups, correctly detected repeated words showed a more positive ERP waveform than new words between 350msec and 550msec after stimulus presentation. Although we found no group difference of this old-new effect for emotionally neutral words, patients had a smaller effect than control subjects for negative and positive words. This finding is discussed with respect to the literature and is viewed as evidence for changed memory mechanisms for emotionally charged words in patients with TS and OCD.