Ocular tilt reaction as a delayed complication of deep brain stimulation for Parkinson disease.

A 57-year-old-man treated with deep brain stimulation (DBS) of both subthalamic nuclei for advanced Parkinson disease developed a brain hemorrhage near the site of one of the DBS electrodes 9 months after implantation. The hemorrhage caused vertical diplopia from skew deviation. Examination also disclosed evidence of ipsiversive binocular torsion and a right head tilt, constituting an ocular tilt reaction (OTR). Fourteen months later, he was still symptomatic from diplopia. An OTR has not previously been reported as a delayed complication of DBS.