Smooth Pursuit and Fixation Ability in Children With Tourette Syndrome

OBJECTIVE: The smooth pursuit eye movements and fixation ability of children aged 8 to 16 years with Tourette syndrome (TS) were examined. BACKGROUND: Although several studies have examined the saccadic ability of patients with TS, there have been only a few studies examining pursuit ability in TS. METHOD: Pursuit gain (eye velocity/target velocity) and intrusive saccades during fixation were measured in children with TS-only, TS+attention deficit hyperactivity disorder (ADHD), and TS+ADHD+obsessive compulsive disorder (OCD), and in controls (8 to 16 y). Two pursuit tasks and 1 fixation task were used. In random pursuit 1 (RP1), each step and ramp cycle began from fixation; in random pursuit 2 (RP2), each cycle followed the next. In the fixation task, children were required to maintain fixation on a center dot and ignore distractor stimuli. RESULTS: All children had significantly higher pursuit gains in RP2 than in RP1 when pursuing a 30 degrees/s moving target. In addition, in RP2, the TS+ADHD+OCD group displayed significantly higher pursuit gains relative to the TS-only, TS+ADHD, and control groups. In the fixation task, the TS+ADHD group exhibited significantly more intrusive saccades than the TS+ADHD+OCD and control groups. CONCLUSIONS: Our findings support an enhanced oculomotor ability in the TS+ADHD+OCD group and the presence of an online gain control mechanism during ongoing pursuit. These findings are discussed in more detail.

Smooth Pursuit and Fixation Ability in Children With Tourette Syndrome Journal Articles