Parkinson Disease (PD) patients experience a variety of motor issues such as walking difficulties, loss of balance, and freezing while walking, which impacts their quality of life. Some symptoms, like freezing of gait (FOG), do not respond to medications typically used to treat PD. Current surgical procedures used to alleviate PD symptoms also do not always improve FOG. Since many traditional therapies have failed for the treatment of FOG, researchers have proposed the use of newer treatments. Recent research in animal models and clinical human data using SCS has produced promising results, specifically showing improvement in FOG with the use of SCS in patients with PD. The purpose of this study is to evaluate the effectiveness of spinal cord stimulation (SCS) for the management of freezing of gait (FOG) that does not respond to conventional treatments in subjects with Parkinson's disease (PD). The investigators hypothesize that SCS significantly decreases FOG episodes in patients with PD. 1. Assess the safety, tolerability and preliminary evidence of effectiveness of upper thoracic spinal cord stimulation for freezing of gait in Parkinson's (PD) patients. 2. Explore the effects of two SCS programming paradigms on motor, nonmotor and quality of life measures in PD patients with freezing of gait.