Effects of Simultaneous Bilateral Subthalamic Nucleus and Pedunculopontine Nucleus Deep Brain Stimulation on Saccades in Advanced Parkinson Disease

Aims: The basal ganglia (BG) consist of various components, one of which, the subthalamic nucleus (STN), is thought to be involved in controlling saccades. 1 Another brainstem structure, the pedunculopontine nucleus (PPN) has extensive connections with the BG. Recently, deep brain stimulation (DBS) of STN and PPN has been used to treat advanced Parkinson disease (PD). 2–4 Here we consider the effects of simultaneous bilateral STN and PPN-DBS on both initiation and inhibition of saccades in advanced PD, not previously reported. Methods: Five patients with advanced PD performed two different oculomotor tasks during off-DBS, bilateral STN-DBS, bilateral PPN-DBS, and simultaneous bilateral STN and PPN-DBS. The first task tested visually guided saccades (VGS) that were reflexive and the second tested antisaccades (AS) that were volitional. Saccadic latency, accuracy, and velocity were measured. Advanced PD patients not receiving DBS treatment, age-matched, and young healthy subjects all acted as controls (12 each). Results: Simultaneous bilateral STN and PPN-DBS produced the greatest improvement in all parameters for the VGS task and the AS (volitional) task as compared with Off-DBS ( p < 0.001). The effect of simultaneous bilateral STN and PPN-DBS was greater than the improvement caused by STN-DBS alone for the velocities ( p < 0.05) and number of prosaccades ( p < 0.01) for the AS task (ANOVA and Tukey-Kramer testing). Conclusion: Simultaneous STN and PPN-DBS may correct the functional level of the superior colliculi for both saccade initiation and inhibition in advanced PD. Acknowledgments: We thank The Medical Research Council, United Kingdom, (MRC) and Medtronic for help in funding our work. References 1 Yugeta A, et al. Neurology 2010;74(9):743 2 Stefani A, et al. Brain 2007;130(Pt 6):1596 3 Ferraye MU, et al. Brain 2010;133(Pt 1):205 4 Moro E, et al. Brain 2010;133(Pt 1):215