VERTICAL GAZE PALSY AFTER THALAMIC STIMULATION FOR TOURETTE SYNDROME : CASE REPORT

We describe a patient who developed a vertical gaze paralysis after deep brain stimulation performed for intractable Tourette syndrome due to a small deep bleeding in the upper mesencephalon. A 39-year-old man underwent thalamic deep brain stimulation for intractable Tourette syndrome. Immediately postoperatively, he had diplopia and dizziness. The neurological examination revealed vertical gaze palsy with preserved vertical oculocephalic movements. A postoperative computed tomography scan revealed a discrete high-density lesion across the midline at the distal end of the left electrode. This area corresponds with the pretectal area, including the rostral interstitial nucleus of the medial longitudinal fasciculus, with sparing of the oculomotor and rubral nuclei. Six months postoperatively, maximal upward and downward smooth pursuit eye movements were achieved. Upward saccadic velocities were still reduced by 20 to 25 degrees. This case report describes a complication that might demand special attention during the planning of thalamic deep brain stimulation for the treatment of Tourette syndrome. Examination of both horizontal and vertical eye movements during deep brain stimulation surgery is recommended.