Oculomotor Nerve Hyperactivation Causing Diplopia During High Frequency Stimulation for Parkinson's Disease

Twenty-five patients with Parkinson's disease successfully treated by bilateral high frequency stimulation (HFS) of the subthalamic nucleus were tested postoperatively to determine the optimal stimulation parameters. When HFS was applied below the effective contact used for long-terme therapy, at the junction between the substantia nigra and the antero-dorsal part of the red nucleus where the third cranial nerve emerges, four patients experienced reversible acute diplopia caused by ocular motor dysfunction of the eye ipsilateral to the stimulation.