This is a single-center phase I clinical study aiming to improve gait functions in patients with Parkinson's disease (PD) by using adaptive neurostimulation to the pallidum. The investigators will use a bidirectional deep brain stimulation device with sensing and stimulation capabilities to 1) decode the physiological signatures of gait and gait adaptation by recording neural activities from the motor cortical areas and the globus pallidus during natural walking and a gait adaptation task, and 2) develop an adaptive deep brain stimulation (DBS) paradigm to selectively stimulate the pallidum during different phases of the gait cycle and measure improvements in gait parameters. This is the first exploration of network dynamics of gait in PD using chronically implanted cortical and subcortical electrodes. In addition to providing insights into a fundamental process, the proposed therapy will deliver personalized neurostimulation based on individual physiological biomarkers to enhance locomotor skills in patients with PD. Ten patients with idiopathic Parkinson's disease undergoing evaluation for DBS implantation will be enrolled in this single treatment arm study.
This study will allow the investigators to evaluate the efficacy of an adaptive stimulation paradigm in deep brain stimulation (DBS) to treat motor-related behaviours and motor skill learning in Parkinson's disease (PD). Parkinson's disease patients will be implanted unilaterally or bilaterally with a totally internalized bidirectional neural interface, Medtronic Summit RC+S. While current DBS therapy improves motor symptoms of PD, it does not address problems with acquiring additional motor skills (i.e. adapting gait patterns to avoid falls)) in PD, therefore, limiting benefits of physical rehabilitation programs aimed at improving mobility. Motor skill learning is critical in acquiring any new behaviors related to motor function. The overall objective is to identify personalized electrophysiological signatures of motor skill learning in PD patients and use adaptive control algorithms to enhance these signatures. The study will discover new ways to rehabilitate the disease brain circuits using adaptive neuromodulation. In a small, double-blinded trial, ten patients with idiopathic PD and motor fluctuations will be implanted with unilateral or bilateral RC+S devices, each connected to a standard quadripolar DBS lead implanted in the basal ganglia, along with a 4-contact paddle type electrode placed subdurally over the motor cortex. The investigators will compare the overall efficacy of closed-loop and open-loop paradigms in terms of behavioral performance improvements in validated motor skill learning tasks and measurements from wearable devices. During this chronic adaptive DBS phase, adaptive DBS and open-loop stimulation settings will be randomized for 30-day periods and motor skill and gait related measurements will be obtained from a combination of computerized motor tasks and wearable devices that track movement kinematics. Patients will participate in daily, if possible, motor learning and gait tasks at home with triggered stimulation settings and recordings. The investigators expect to successfully develop a prototype adaptive DBS algorithm based on cortical and / or basal ganglia LFPs (local field potentials). The investigators hypothesize that an adaptive paradigm will provide improvements in motor skilled learning compared to the conventional, open-loop paradigm, in which stimulation parameters remain constant until changed by the patient or clinician using an external programmer.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
10
Using the RC+S pulse generator, patients receive clinically-optimized open loop DBS stimulation to the pallidum.
Using the RC+S pulse generator, the patients will receive closed-loop stimulation at random time points. These random stimulation times will in total equal the total amount of time of active movement.
Using the RC+S pulse generator, the patients will receive closed-loop stimulation during time of contralateral limb movement (e.g. left brain stimulation during right leg/arm movement).
Using the RC+S pulse generator, the patients will receive closed-loop stimulation during time of no movement for the contralateral limb (e.g. left brain stimulation while right leg/arm is not moving).
UCSF
San Francisco, California, United States
Change in motor learning task completion with closed-loop compared to open-loop deep brain stimulation (DBS)
Change in percentage of motor learning task trials that were completed with closed-loop compared to open-loop deep brain stimulation (DBS). The task is made up of 840 trials, completion will be measured by percent of trials completed (e.g. 750/840 trials completed would be 89%). The task has a built in function which logs completed trials in a CSV document.
Time frame: Baseline and 2 years
Change in motor learning task reaction times with closed-loop compared to open-loop deep brain stimulation (DBS)
Change in gait sequence motor learning task reaction times (measured in milliseconds) with closed-loop compared to open-loop deep brain stimulation (DBS).
Time frame: Baseline and 2 years
Change in motor learning task mean accuracy with closed-loop compared to open-loop deep brain stimulation (DBS).
Change in motor learning task mean accuracy with closed-loop compared to open-loop deep brain stimulation (DBS). Accuracy will be measured as a percent using the tasks proprietary output log which records which trials out of the 840 total trials were target hits (i.e. correct trials). Mean accuracy will be calculated by taking the average of each patient's accuracy score across all attempts of the task done by said patient.
Time frame: Baseline and 2 years
Change in Gait
Change in gait measurements using the 10-meter walk timed test. The 10-Meter Walk Test (10MWT) is a performance measure used to assess walking speed in meters per second over a short distance of 10 meters. It is employed to determine functional mobility and gait. The gait speed is used as the outcome by which to compare change in performance capacity. Lower times indicate higher levels of physical functioning.
Time frame: Baseline and 2 years
Change in Balance
Change in balance measurements using: Mini-Best Test: Clinical balance assessment tool. The score range is 0-2 with high score indicating higher levels of physical functioning. Activities-Specific Balance Confidence Scale (ABC): Measures of confidence in performing various ambulatory activities without falling or experiencing a sense of unsteadiness. The score range is 0-100 with higher scores indicating higher levels of physical functioning.
Time frame: Baseline and 2 years
Change in MDS-UPDRS III scores
Change in Movement Disorders Society Unified Parkinson Disease Rating Scale (MDS-UPDRS) III score. The scale consists of 18 items that are each scored 0 to 3, making the total score out of 72 points, with higher scores indicating higher impairment.
Time frame: Baseline and 2 years
Change in NIHTB Cognition Battery Test
Change in National Institute of Health Toolbox (NIHTB) Cognition battery test (during adaptive stimulation compared to open loop stimulation). A score known as a theta score is calculated for each participant; it represents the relative overall ability or performance of the participant. The theta score is converted to a Computed Score which ranges from roughly 0 to 2000 depending on the age-adjusted averages, with higher scores indicating higher levels of cognitive functioning.
Time frame: Baseline and 2 years
Change in Five-Times Sit to Stand Test Results
Five-Times Sit to Stand Test: Assesses functional lower extremity strength, transitional movements, balance, and fall risk in older adults. Scoring based on amount of time a patient is able to transfer from a seated to a standing position and back to sitting five times, with lower times indicating higher levels of physical functioning.
Time frame: Baseline and 2 years
Change in Stride Length
Change in stride length measured by Rover (a gait measurement device) and Xsens (a kinematic measurement device) with closed-loop compared to open-loop deep brain stimulation (DBS). Stride length is measured in meters.
Time frame: Baseline and 2 years
Change in Stride Time
Change in stride time measured by Rover (a gait measurement device) and Xsens (a kinematic measurement device) with closed-loop compared to open-loop deep brain stimulation (DBS). Stride time is measured in seconds.
Time frame: Baseline and 2 years
Change in double support time
Change in double support time measured by Rover (a gait measurement device). Each gait cycle consists of two phases, where both feet are in contact with the ground, called Double Support. Double support time will be measured in seconds (i.e. amount of time both feet are in contact with the ground).
Time frame: Baseline and 2 years
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