O1-E-25. The effect of obsessive compulsive disorder on saccade performance in Gilles de la Tourette (GTS) syndrome

Abstract

Tics in patients with Gilles de la Tourette syndrome (GTS) are generally considered due to emergence of focal hyperactivity within the basal ganglia (BG) – thalamocortical circuit. In order to elucidate the pathophysiology of GTS, we recorded saccade performance in 226 patients using the visually guided (VGS) and memory guided saccade (MGS) tasks, and compared it with that of 216 age-matched control subjects. We also analyzed whether the saccade parameters varied with the severity of accompanying obsessive compulsive disorder (OCD) as well as use (73 cases) or nonuse (153 cases) of dopamine receptor blockers (DA blockers). In GTS, MGS latency was prolonged compared with normal subjects, suggesting impaired function of the direct pathway of the BG. The frequency of saccades to cue was increased and VGS latency was normal to slightly shortened, pointing to the impaired inhibitory control of saccades due to disinhibiton of the superior colliculus. All these changes tended to be worse with severer OCD symptoms, and with the use of DA blockers. The findings suggest that BG dysfunction in GTS gets worse with OCD and use of DA blocker, and that we should take special care when using DA blockers in GTS patients with OCD.