Postural Instability and Gait Disorder After Subthalamic Nucleus Deep Brain Stimulation

Abstract

Parkinson disease (PD) patients who have undergone surgery and develop festinating gait and postural instability are challenging to diagnose and treat. This chapter describes the case of an early-onset PD patient who underwent deep brain stimulation (DBS) 4 years after disease onset due to motor and nonmotor fluctuations and medication side effects (impulse control disorder). A year after surgery, the patient developed gait and balance problems in the on-medication/on-stimulation states that resolved after turning stimulation off or withdrawing medication for 12 hours. However, other symptoms, including as bradykinesia, rigidity, and tremor, reappeared. Troubleshooting involved magnetic resonance imaging to evaluate electrode placement and complete screening of all contacts with successful reprogramming and medication adjustments. The pathophysiology of balance problems is discussed, including the synergistic effects of subthalamic nucleus DBS and dopaminergic treatment, which may lead to increased postural sway and lower limb dystonia.