The objective of this study is to further the understanding and application of 60Hz subthalamic deep brain stimulation (STN-DBS) in Parkinson's patients with gait disorder. The investigators will achieve this through 2 study aims:

1. Determine the impact of 60Hz subthalamic deep brain stimulation on gait kinematics using wearable sensors
2. Develop machine learning models to predict optimal subthalamic deep brain stimulation frequency based on wearable sensors

Gait disorder, which manifests as shuffling, reduction in speed, multistep turning, and/or freezing of gait (FOG), can arise later in the Parkinson's disease (PD) course and cause significant disability. Ultimately, patients are at risk for falls and can become socially isolated due to their mobility limitations. These symptoms tend not to respond to high frequency STN-DBS. However, lower frequency stimulation (60-80Hz) of the STN in treating gait disorder and/or freezing of gait has demonstrated benefit. This study potentially can expand knowledge of 60hz DBS while improving its utilization in combination with PD medications-enabling sustainable and possibly predictable therapeutic benefit.

Inclusion Criteria:

1. Male or female, aged 21-80
2. Patients diagnosed with Parkinson's disease (PD)
3. PD subjects who have bilateral STN-DBS (greater than 3 months) or in the preoperative stage of being implanted with bilateral STN-DBS
4. Have underlying gait disorder
5. Currently treated with oral levodopa therapy
6. Willingness to comply with all study procedures

Exclusion Criteria:

1. Cognitive deficits based on historical record that limit participant compliance with study protocol
2. Vestibular disorder or musculoskeletal problems affecting gait or balance

Adverse events was assessed during each study visit day. At total of 2-3 study visits over 6 weeks

Adverse Events were monitored for all enrolled subjects during the study period.