Deep brain stimulation (DBS) in the dorsal region of the subthalamic nucleus (STN) is very effective for reducing motor symptoms of Parkinson's disease (PD). Modeling studies suggest that this therapy may result in current spread into the ventral STN, causing altered cognitive processes. As a result, current stimulation parameters often lead to worsening in verbal fluency, executive function, and, particularly, cognitive control. There is evidence suggesting that low frequency oscillatory activity occurs across brain circuits important in integrating information for cognition. Preclinical studies and human recording studies indicate these low frequency theta oscillations drive cognitive control during cognitive tasks. Thus, the purpose of this study is to determine the safety, tolerability, and efficacy of low frequency stimulation (LFS) of the ventral STN alongside standard high frequency stimulation (HFS) of the dorsal STN in patients with PD.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
10
Patients with idiopathic Parkinson's disease who have previously been implanted with the Boston Scientific VerciseTM DBS system for at least 3 months. These patients will already be receiving high-frequency dorsal STN stimulation as part of the standard of care for PD. Once patients have provided consent and are enrolled in this study, they will receive simultaneous low-frequency stimulation of the ventral STN to examine if there are any effects on cognitive performance.
UC Davis Health
Sacramento, California, United States
RECRUITINGMean Change from Baseline in Depression Scores on the Center for Epidemiologic Studies Depression Scale (CES-D)
The score of the CES-D will be compared across sessions and a score that rises above 20 (out of 60) will be considered positive for the development of depression.
Time frame: Baseline, Week 2, Week 6, Month 3, and Month 6
Mean Change from Baseline in Impulsiveness Scores on the Barratt Impulsiveness Scale (BIS-11)
The score of the BIS-11 will be evaluated across sessions and elevated scores indicate greater impulsivity and risk-taking behavior. The scale involves 30 questions with values from 1-4. Overall scores range from 30-120.
Time frame: Baseline, Week 2, Week 6, Month 3, and Month 6
Mean Change from Baseline in Neuropsychiatric Inventory (NPI)
The NPI assesses frequency, change in severity, and distress over 12 neuropsychiatric domains as evaluated by the caregiver. We will look for a significant score reduction in any domain of the NPI.
Time frame: Baseline, Week 2, Week 6, Month 3, and Month 6
Mean Change from Baseline in Movement Scores on Part III of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS)
Part III of the MDS-UPDRS consists of 18 areas of motor assessments to assess severity of symptoms. Each score is rated in terms of severity from 0-4, with higher scores indicating higher severity of symptoms. A composite score will be evaluated for changes from baseline.
Time frame: Baseline, Week 2, Week 6, Month 3, and Month 6
Mean Change from Baseline in Cognitive Performance Scores on the Montreal Cognitive Assessment - Blind (MoCA)
This will be collected via telephone calls. The MoCA-Blind has been validated for telephone administration. We will re-evaluate MoCA-Blind scores during telephone monitoring to assess any changes to cognitive ability. A total score of less than 15 out of a possible 22 indicates greater than mild cognitive impairment.
Time frame: Baseline, Hour 24, Week 1, Month 1, Month 2, Month 4, and Month 5
Mean Change from Baseline in Depression Scores on the CES-D Short Version (CES-D-R10)
This will be collected via telephone calls. Patients will be given an unmarked form with questions and will be able to follow along the telephone conversation and answer each question (0-4 severity rating scale) for 10 questions focused on patient affect. A total score greater than 10 (out of 30) indicates the development of depression symptoms.
Time frame: Baseline, Hour 24, Week 1, Month 1, Month 2, Month 4, and Month 5
Mean Change from Baseline in Motor and Non-Motor Aspects of Daily Living Scores on Parts I and II of the MDS-UPDRS
This will be collected via telephone calls. Patients will be asked questions relating to motor and non-motor aspects of daily living and to rate the severity of their symptoms on a scale from 0-4, with higher scores indicating higher severity of symptoms. We will assess for changes in the composite score from baseline.
Time frame: Baseline, Hour 24, Week 1, Month 1, Month 2, Month 4, and Month 5
Mean Change from Baseline in Decision-Making Scores on Probabilistic Gambling Task
A patient-specific measure of risk attitude during a gambling task. We will estimate indifference points (win probability at which risky choice is chosen 50% of the time) at each time point and compare to those points during baseline performance on the task.
Time frame: Baseline, Minute 30, Week 2, Week 6, Month 3, and Month 6
Mean Change from Baseline in Inter-Temporal Choice Scores on a Temporal Discounting Task
A patient-specific measure of risk attitude during a temporal preferences task. We will examine the area under the curve of the empirical discount functions of 'larger later' rewards and 'smaller sooner' rewards. Smaller values indicate increased preference for smaller sooner over larger later rewards. Scores will be compared to baseline performance on the task.
Time frame: Baseline, Minute 30, Week 2, Week 6, Month 3, and Month 6
Mean Change from Baseline in Verbal Fluency Scores on Word Generation Task
The average number of words generated in a 1-minute time frame.
Time frame: Baseline, Minute 30, Week 2, Week 6, Month 3, and Month 6
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.