Parkinson Disease
Conditions
Keywords
Parkinson's disease, axial motor dysfunction, asymmetric neuromodulation, subthalamic nucleus deep brain stimulation
Brief summary
This single-center, randomized, quadruple-blinded, double-crossover comparative efficacy trial will study the effects of unilateral 50% voltage reduction in axial motor dysfunction for patients with Parkinson's disease that develop treatment-resistant postural stability gait dysfunction after bilateral subthalamic nucleus deep brain stimulation surgery.
Interventions
OTHERAsymmetric STN-DBS
Asymmetric deep brain stimulation
Sponsors
University of Toronto
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
Inclusion criteria
* Patients with Parkinson's disease (PD) (previously diagnosed according to the UK brain bank criteria) who develop treatment-resistant postural instability gait dysfunction (PIGD) more than 6 months but less than 5 years after bilateral subthalamic nucleus deep brain stimulation (STN-DBS). * Treatment-resistant PIGD will be defined as freezing of gait and UPDRS or MDS-UPDRS PIGD subscales of more than 6 points despite optimization of medications and bilateral STN-DBS programming.
Exclusion criteria
* Treatment-resistant PIGD less than 6 months or more than 5 years after STN-DBS surgery. * PIGD responsive to optimization of medications and/or bilateral STN-DBS programming. * Cognitive impairment or psychiatric comorbidities (including substance abuse) that would interfere with the informed consent process, study adherence or outcome assessments. * Advanced PD or any other neurological, cardiovascular or musculoskeletal co-morbidities that would preclude or require assistance to complete the 10-meter walking test. * Patients not able to comply with 4-week interval evaluations following their potential enrollment due to personal reasons. * Serious illness (requiring systemic treatment and/or hospitalization) until subject either completes therapy or is clinically-stable on therapy, in the opinion of the site investigator, for at least 30 days prior to study entry. * Inability or unwillingness of subject or legal guardian/representative to give written informed consent.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Gait Velocity | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | As measured during the 10-meter walk test. In this test, participants walk at their usual, regular pace over a total distance of 10 meters. The middle 6-meters (between the 2-meter and 8-meter marks) are timed to measure gait velocity during steady-state gait. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Axial Motor Function (1) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | As measured by the Mini-BESTest. The Mini-BESTest is a shorter version of the BESTest (Balance Evaluation Systems Test). It is a clinical and research tool to measure balance control. The Mini-BESTest has 14 items, scored from 0-2 each, so the minimum score is 0 and the maximum score is 28. Lower scores indicate worse balance control and higher scores indicate better balance control. |
| Change in Axial Motor Function (2) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | As measured by the UPDRS-PIGD sub-scale. The UPDRS-PIGD is the Postural Instability Gait Dysfunction (PIGD) sub-scale of the Unified Parkinson's Disease Rating Scale (UPDRS). It is a clinical and research tool to measure PIGD. The UPDRS-PIGD has 5 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 20. Lower scores indicate better PIGD and higher scores indicate worse PIGD. |
| Change in Axial Motor Function (3) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | As measured by the Freezing of Gait Questionnaire. The Freezing of Gait Questionnaire is a clinical and research tool to measure freezing of gait. It has 6 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 24. Lower scores indicate better and higher scores indicate worse freezing of gait, respectively. |
| Change in Quantitative Gait Analysis (1) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Changes in gait velocity in m/s as measured by a quantitative gait analysis system (Zeno walkway). |
| Change in Quantitative Gait Analysis (2) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Changes in step length in cm (mean, right, left) as measured by a quantitative gait analysis system (Zeno walkway). Step length difference = \[right - left step length\] |
| Change in Quantitative Gait Analysis (3) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Step length ratio = \[right step length\] / \[left step length\] Step length symmetry = (\[right - left step length\] / \[right + left step length\]) |
| Change in Motor Function | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | As measured by the MDS-UPDRS (Movement Disorders Society Unified Parkinson's Disease Rating Scale), which is a clinical and research tool to measure symptoms and signs of Parkinson's disease. It has 4 parts: I (non-motor experiences of daily living), II (motor experiences of daily living), III (motor exam) and IV (motor complications). The MDS-UPDRS has 60 items, scored from 0-4 each. The minimum score is 0 and the maximum score is 240. The MDS-UPDRS (motor) is Part III and measures motor signs. It has 28 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 112. The MDS-UPDRS (axial motor) is composed of items 3.1 to 3.3a and 3.9 to 3.13 of Part III of the MDS-UPDRS and measures axial motor signs. It has 8 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 32. In the MDS-UPDRS total, motor and axial motor sub-scales, lower scores indicate better symptoms/signs and higher scores indicate worse symptoms/signs, respectively. |
| Change in Quantitative Speech Analysis (2) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Changes in loudness in decibels (dB) as measured by the Praat software. |
| Change in Quantitative Speech Analysis (3) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Changes in jitter measured in percentage by the Praat software. In this case, jitter is the percentage change in the stability of the frequency of speech tone (i.e. speech cycle-to-cycle frequency variation) |
| Change in Quantitative Speech Analysis (4) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Changes in shimmer measured in percentage by the Praat software. In this case, shimmer is the percentage change in the stability of the amplitude of speech tone (i.e. speech cycle-to-cycle amplitude variation) |
| Change in Quality of Life | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | As measured by the Total Score of the 39-item Parkinson's Disease Quality of Life Questionnaire (PDQ-39). The PDQ-39 is a clinical and research tool to measure quality of life in Parkinson's disease. It has 39 questions, which patients score as never (0% of the time), occasionally (25% of the time), sometimes (50% of the time), often (75% of the time) or always (100% of the time). The PDQ-39 Total Score or Summary Index is the average of the 39 questions, expressed. The minimum score is 0% (never) and the maximum score is 100% (always). Lower scores indicate better quality of life and higher scores indicate worse quality of life. |
| Change in Select Cognitive Tasks | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Left brain cognitive function: Hopkins Verbal Learning Test-Revised: Total recall trials 1-3 (0-36), delayed recall (0-12); Phonemic Verbal Fluency (0-no max); Semantic Verbal Fluency (Animal cue) (0-no max); Letter 1-back and 2-back working memory tasks (0-100%). Right brain cognitive function: Brief Visual Memory Test-Revised: Total recall trials 1-3 (0-36), delayed recall (0-12); Computerized landmark line bisection (-10 to 10); Spatial 1-back and 2-back working memory tasks (0-100%). Ranges in parentheses. Line bisection: closer to 0 is more accurate. For the rest: higher values are better |
| Change in Quantitative Speech Analysis (1) | Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2) | Changes in pitch in Hertz (Hz) as measured by the Praat software. |
Countries
Canada
Participant flow
Recruitment details
38 patients with Parkinson's disease (PD) who developed postural instability gait dysfunction (PIGD) after bilateral subthalamic (STN) deep brain stimulation (DBS) were screened for eligibility between January 22, 2018 and January 29, 2019 at the DBS clinic of the Movement Disorders Center at the University of Toronto in Toronto, Ontario, Canada.
Pre-assignment details
22 of 38 patients were enrolled. Of the 16 patients not enrolled, 9 did not meet inclusion criteria and 7 declined to participate. There were no significant events between enrollment and randomization. The first study participant was enrolled on March 14, 2018. The last study participant was enrolled on January 29, 2019.
Participants by arm
| Arm | Count |
|---|---|
| All Study Participants All Study Participants | 22 |
| Total | 22 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 | FG004 | FG005 | FG006 | FG007 |
|---|---|---|---|---|---|---|---|---|---|
| Open Label Phase | Symptom worsening (Treatment failure) | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 |
Baseline characteristics
| Characteristic | All Study Participants |
|---|---|
| Age, Continuous | 65.5 years |
| Baseline left STN-DBS amplitude | 4.08 Volts |
| Baseline left STN-DBS frequency | 80 Hertz |
| Baseline left STN-DBS pulse width | 60 Microseconds |
| Baseline left STN-DBS type Conventional bipolar | 2 Participants |
| Baseline left STN-DBS type Conventional monopolar | 0 Participants |
| Baseline left STN-DBS type Double low-frequency monopolar | 0 Participants |
| Baseline left STN-DBS type High-frequency bipolar | 2 Participants |
| Baseline left STN-DBS type High-frequency monopolar | 1 Participants |
| Baseline left STN-DBS type Interleaving conventional monopolar / bipolar | 1 Participants |
| Baseline left STN-DBS type Interleaving low-frequency monopolar | 4 Participants |
| Baseline left STN-DBS type Interleaving low-frequency monopolar/double monop. | 1 Participants |
| Baseline left STN-DBS type Low-frequency bipolar | 3 Participants |
| Baseline left STN-DBS type Low-frequency monopolar | 8 Participants |
| Baseline right STN-DBS amplitude | 3.95 Volts |
| Baseline right STN-DBS frequency | 80 Hertz |
| Baseline right STN-DBS pulse width | 60 Microseconds |
| Baseline right STN-DBS type Conventional bipolar | 1 Participants |
| Baseline right STN-DBS type Conventional monopolar | 1 Participants |
| Baseline right STN-DBS type Double low-frequency monopolar | 1 Participants |
| Baseline right STN-DBS type High-frequency bipolar | 0 Participants |
| Baseline right STN-DBS type High-frequency monopolar | 3 Participants |
| Baseline right STN-DBS type Interleaving conventional monopolar / bipolar | 1 Participants |
| Baseline right STN-DBS type Interleaving low-frequency monopolar | 4 Participants |
| Baseline right STN-DBS type Interleaving low-frequency monopolar/double monop. | 1 Participants |
| Baseline right STN-DBS type Low-frequency bipolar | 2 Participants |
| Baseline right STN-DBS type Low-frequency monopolar | 8 Participants |
| Baseline total electrical energy delivered (TEED) to the left STN | 89.66 Joules/second |
| Baseline total electrical energy delivered (TEED) to the right STN | 88.59 Joules/second |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 22 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Freezing of gait questionnaire | 14.5 units on a scale |
| Gait velocity | 0.976 m/s |
| Hand dominance | 82.5 units on a scale |
| Indication for STN-DBS surgery Medication-resistant motor fluctuations | 14 Participants |
| Indication for STN-DBS surgery Medication-resistant tremor | 8 Participants |
| Levodopa equivalent daily dose | 1037.5 mg/day |
| MDS-UPDRS (axial motor) | 16.5 units on a scale |
| MDS-UPDRS (motor) | 45.5 units on a scale |
| MDS-UPDRS (total) | 89 units on a scale |
| Mini-BESTest score | 15 units on a scale |
| More affected hemibody at enrollment Both | 14 Participants |
| More affected hemibody at enrollment Left | 4 Participants |
| More affected hemibody at enrollment Right | 4 Participants |
| More affected hemibody at onset Both | 1 Participants |
| More affected hemibody at onset Left | 8 Participants |
| More affected hemibody at onset Right | 13 Participants |
| Parkinson's disease duration | 17 years |
| Predominant motor symptom at onset Stiffness and/or Slowness | 13 Participants |
| Predominant motor symptom at onset Tremor | 9 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 5 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 17 Participants |
| Region of Enrollment Canada | 22 Participants |
| Select cognitive tasks Brief Visual Memory Test-Revised: Delayed Recall | 5.15 units on a scale STANDARD_DEVIATION 3.38 |
| Select cognitive tasks Brief Visual Memory Test-Revised: RecallTrials 1-3 | 12.75 units on a scale STANDARD_DEVIATION 6.24 |
| Select cognitive tasks Computerized landmark line bisection task | 0.08 units on a scale STANDARD_DEVIATION 0.53 |
| Select cognitive tasks HopkinsVerbal LearningTest-Revised: Delayed Recall | 7.70 units on a scale STANDARD_DEVIATION 2.56 |
| Select cognitive tasks HopkinsVerbalLearningTest-Revised: RecallTrials1-3 | 21.75 units on a scale STANDARD_DEVIATION 5.78 |
| Select cognitive tasks Letter 1-Back Working Memory Task | 82.86 units on a scale STANDARD_DEVIATION 18.51 |
| Select cognitive tasks Letter 2-Back Working Memory Task | 55.11 units on a scale STANDARD_DEVIATION 26.28 |
| Select cognitive tasks Phonemic Verbal Fluency | 31.50 units on a scale STANDARD_DEVIATION 14.15 |
| Select cognitive tasks Semantic Verbal Fluency (Animal cue) | 16.80 units on a scale STANDARD_DEVIATION 7.82 |
| Select cognitive tasks Spatial 1-Back Working Memory Task | 85.20 units on a scale STANDARD_DEVIATION 23.22 |
| Select cognitive tasks Spatial 2-Back Working Memory Task | 57.81 units on a scale STANDARD_DEVIATION 29.1 |
| Sex: Female, Male Female | 7 Participants |
| Sex: Female, Male Male | 15 Participants |
| Summary index of the PDQ-39 | 31.54 units on a scale |
| Time between STN-DBS surgery and onset of axial dysfunction | 14.5 months |
| Time since STN-DBS surgery | 51 months |
| UPDRS-PIGD score | 11 units on a scale |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk | EG004 affected / at risk |
|---|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 22 | 0 / 22 | 0 / 22 | 0 / 7 | 0 / 10 |
| other Total, other adverse events | 0 / 22 | 8 / 22 | 3 / 22 | 1 / 7 | 2 / 10 |
| serious Total, serious adverse events | 0 / 22 | 0 / 22 | 0 / 22 | 0 / 7 | 0 / 10 |
Outcome results
Primary
Change in Gait Velocity
As measured during the 10-meter walk test. In this test, participants walk at their usual, regular pace over a total distance of 10 meters. The middle 6-meters (between the 2-meter and 8-meter marks) are timed to measure gait velocity during steady-state gait.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to report the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Gait Velocity | 0.941 m/s | Standard Error 0.086 |
| Asymmetric STN-DBS 1 | Change in Gait Velocity | -0.069 m/s | Standard Error 0.048 |
| Asymmetric STN-DBS 2 | Change in Gait Velocity | -0.016 m/s | Standard Error 0.048 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.163Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.749Mixed Models Analysis
Secondary
Change in Axial Motor Function (1)
As measured by the Mini-BESTest. The Mini-BESTest is a shorter version of the BESTest (Balance Evaluation Systems Test). It is a clinical and research tool to measure balance control. The Mini-BESTest has 14 items, scored from 0-2 each, so the minimum score is 0 and the maximum score is 28. Lower scores indicate worse balance control and higher scores indicate better balance control.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to report the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Axial Motor Function (1) | 0.967 units on a scale | Standard Error 0.068 |
| Asymmetric STN-DBS 1 | Change in Axial Motor Function (1) | -0.017 units on a scale | Standard Error 0.828 |
| Asymmetric STN-DBS 2 | Change in Axial Motor Function (1) | 1.557 units on a scale | Standard Error 0.828 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.984Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.067Mixed Models Analysis
Secondary
Change in Axial Motor Function (2)
As measured by the UPDRS-PIGD sub-scale. The UPDRS-PIGD is the Postural Instability Gait Dysfunction (PIGD) sub-scale of the Unified Parkinson's Disease Rating Scale (UPDRS). It is a clinical and research tool to measure PIGD. The UPDRS-PIGD has 5 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 20. Lower scores indicate better PIGD and higher scores indicate worse PIGD.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Axial Motor Function (2) | 0.909 units on a scale | Standard Error 0.153 |
| Asymmetric STN-DBS 1 | Change in Axial Motor Function (2) | -0.549 units on a scale | Standard Error 0.704 |
| Asymmetric STN-DBS 2 | Change in Axial Motor Function (2) | -1.414 units on a scale | Standard Error 0.704 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.44Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.051Mixed Models Analysis
Secondary
Change in Axial Motor Function (3)
As measured by the Freezing of Gait Questionnaire. The Freezing of Gait Questionnaire is a clinical and research tool to measure freezing of gait. It has 6 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 24. Lower scores indicate better and higher scores indicate worse freezing of gait, respectively.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Axial Motor Function (3) | 0.837 units on a scale | Standard Error 0.088 |
| Asymmetric STN-DBS 1 | Change in Axial Motor Function (3) | -0.056 units on a scale | Standard Error 0.807 |
| Asymmetric STN-DBS 2 | Change in Axial Motor Function (3) | -1.888 units on a scale | Standard Error 0.807 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.945Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.024Mixed Models Analysis
Secondary
Change in Motor Function
As measured by the MDS-UPDRS (Movement Disorders Society Unified Parkinson's Disease Rating Scale), which is a clinical and research tool to measure symptoms and signs of Parkinson's disease. It has 4 parts: I (non-motor experiences of daily living), II (motor experiences of daily living), III (motor exam) and IV (motor complications). The MDS-UPDRS has 60 items, scored from 0-4 each. The minimum score is 0 and the maximum score is 240. The MDS-UPDRS (motor) is Part III and measures motor signs. It has 28 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 112. The MDS-UPDRS (axial motor) is composed of items 3.1 to 3.3a and 3.9 to 3.13 of Part III of the MDS-UPDRS and measures axial motor signs. It has 8 items, scored from 0-4 each, so the minimum score is 0 and the maximum score is 32. In the MDS-UPDRS total, motor and axial motor sub-scales, lower scores indicate better symptoms/signs and higher scores indicate worse symptoms/signs, respectively.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Group | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|---|
| Bilateral STN-DBS | Change in Motor Function | MDS-UPDRS (axial motor) | 0.947 units on a scale | Standard Error 0.074 |
| Bilateral STN-DBS | Change in Motor Function | MDS-UPDRS (motor) | 1.080 units on a scale | Standard Error 0.086 |
| Bilateral STN-DBS | Change in Motor Function | MDS-UPDRS (total) | 1.032 units on a scale | Standard Error 0.093 |
| Asymmetric STN-DBS 1 | Change in Motor Function | MDS-UPDRS (total) | 10.058 units on a scale | Standard Error 4.491 |
| Asymmetric STN-DBS 1 | Change in Motor Function | MDS-UPDRS (axial motor) | -1.342 units on a scale | Standard Error 0.823 |
| Asymmetric STN-DBS 1 | Change in Motor Function | MDS-UPDRS (motor) | 4.582 units on a scale | Standard Error 2.147 |
| Asymmetric STN-DBS 2 | Change in Motor Function | MDS-UPDRS (motor) | 1.636 units on a scale | Standard Error 2.147 |
| Asymmetric STN-DBS 2 | Change in Motor Function | MDS-UPDRS (total) | 1.277 units on a scale | Standard Error 4.491 |
| Asymmetric STN-DBS 2 | Change in Motor Function | MDS-UPDRS (axial motor) | -2.453 units on a scale | Standard Error 0.823 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to report the changes associated with the 2 asymmetric conditions.p-value: 0.031Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to report the changes associated with the 2 asymmetric conditions.p-value: 0.778Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.039Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.451Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.111Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.005Mixed Models Analysis
Secondary
Change in Quality of Life
As measured by the Total Score of the 39-item Parkinson's Disease Quality of Life Questionnaire (PDQ-39). The PDQ-39 is a clinical and research tool to measure quality of life in Parkinson's disease. It has 39 questions, which patients score as never (0% of the time), occasionally (25% of the time), sometimes (50% of the time), often (75% of the time) or always (100% of the time). The PDQ-39 Total Score or Summary Index is the average of the 39 questions, expressed. The minimum score is 0% (never) and the maximum score is 100% (always). Lower scores indicate better quality of life and higher scores indicate worse quality of life.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Quality of Life | 0.792 units on a scale | Standard Error 0.154 |
| Asymmetric STN-DBS 1 | Change in Quality of Life | 1.701 units on a scale | Standard Error 2.506 |
| Asymmetric STN-DBS 2 | Change in Quality of Life | -3.148 units on a scale | Standard Error 2.506 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.501Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.216Mixed Models Analysis
Secondary
Change in Quantitative Gait Analysis (1)
Changes in gait velocity in m/s as measured by a quantitative gait analysis system (Zeno walkway).
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Quantitative Gait Analysis (1) | 0.814 m/s | Standard Error 0.095 |
| Asymmetric STN-DBS 1 | Change in Quantitative Gait Analysis (1) | -6.635 m/s | Standard Error 3.91 |
| Asymmetric STN-DBS 2 | Change in Quantitative Gait Analysis (1) | -1.254 m/s | Standard Error 3.91 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.097Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.75Mixed Models Analysis
Secondary
Change in Quantitative Gait Analysis (2)
Changes in step length in cm (mean, right, left) as measured by a quantitative gait analysis system (Zeno walkway). Step length difference = \[right - left step length\]
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Group | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|---|
| Bilateral STN-DBS | Change in Quantitative Gait Analysis (2) | Step length difference | 0.731 cm | Standard Error 0.138 |
| Bilateral STN-DBS | Change in Quantitative Gait Analysis (2) | Step length (left) | 1.015 cm | Standard Error 0.115 |
| Bilateral STN-DBS | Change in Quantitative Gait Analysis (2) | Step length (right) | 0.899 cm | Standard Error 0.156 |
| Bilateral STN-DBS | Change in Quantitative Gait Analysis (2) | Step length (mean) | 0.975 cm | Standard Error 0.129 |
| Asymmetric STN-DBS 1 | Change in Quantitative Gait Analysis (2) | Step length (mean) | -3.097 cm | Standard Error 1.99 |
| Asymmetric STN-DBS 1 | Change in Quantitative Gait Analysis (2) | Step length (right) | -2.867 cm | Standard Error 1.931 |
| Asymmetric STN-DBS 1 | Change in Quantitative Gait Analysis (2) | Step length (left) | -3.293 cm | Standard Error 2.252 |
| Asymmetric STN-DBS 1 | Change in Quantitative Gait Analysis (2) | Step length difference | 0.426 cm | Standard Error 1.088 |
| Asymmetric STN-DBS 2 | Change in Quantitative Gait Analysis (2) | Step length (left) | -3.493 cm | Standard Error 2.252 |
| Asymmetric STN-DBS 2 | Change in Quantitative Gait Analysis (2) | Step length (mean) | -3.191 cm | Standard Error 1.99 |
| Asymmetric STN-DBS 2 | Change in Quantitative Gait Analysis (2) | Step length (right) | -3.800 cm | Standard Error 1.931 |
| Asymmetric STN-DBS 2 | Change in Quantitative Gait Analysis (2) | Step length difference | -0.307 cm | Standard Error 1.088 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.128Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.117Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.145Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.056Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.151Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.129Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.698Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.779Mixed Models Analysis
Secondary
Change in Quantitative Gait Analysis (3)
Step length ratio = \[right step length\] / \[left step length\] Step length symmetry = (\[right - left step length\] / \[right + left step length\])
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Group | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|---|
| Bilateral STN-DBS | Change in Quantitative Gait Analysis (3) | Step length symmetry | 0.934 ratio | Standard Error 0.19 |
| Bilateral STN-DBS | Change in Quantitative Gait Analysis (3) | Step length ratio | 1.214 ratio | Standard Error 0.286 |
| Asymmetric STN-DBS 1 | Change in Quantitative Gait Analysis (3) | Step length ratio | -0.011 ratio | Standard Error 0.071 |
| Asymmetric STN-DBS 1 | Change in Quantitative Gait Analysis (3) | Step length symmetry | 0.421 ratio | Standard Error 2.36 |
| Asymmetric STN-DBS 2 | Change in Quantitative Gait Analysis (3) | Step length ratio | 0.002 ratio | Standard Error 0.071 |
| Asymmetric STN-DBS 2 | Change in Quantitative Gait Analysis (3) | Step length symmetry | -0.420 ratio | Standard Error 2.36 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.874Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.976Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.859Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.86Mixed Models Analysis
Secondary
Change in Quantitative Speech Analysis (1)
Changes in pitch in Hertz (Hz) as measured by the Praat software.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Group | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|---|
| Bilateral STN-DBS | Change in Quantitative Speech Analysis (1) | Pitch (minimum) | 0.434 Hz | Standard Error 0.242 |
| Bilateral STN-DBS | Change in Quantitative Speech Analysis (1) | Pitch (maximum) | 0.735 Hz | Standard Error 0.071 |
| Asymmetric STN-DBS 1 | Change in Quantitative Speech Analysis (1) | Pitch (minimum) | 16.864 Hz | Standard Error 7.931 |
| Asymmetric STN-DBS 1 | Change in Quantitative Speech Analysis (1) | Pitch (maximum) | -146.413 Hz | Standard Error 78.824 |
| Asymmetric STN-DBS 2 | Change in Quantitative Speech Analysis (1) | Pitch (maximum) | -78.213 Hz | Standard Error 78.824 |
| Asymmetric STN-DBS 2 | Change in Quantitative Speech Analysis (1) | Pitch (minimum) | 1.176 Hz | Standard Error 7.931 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.04Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.883Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.071Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.327Mixed Models Analysis
Secondary
Change in Quantitative Speech Analysis (2)
Changes in loudness in decibels (dB) as measured by the Praat software.
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Group | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|---|
| Bilateral STN-DBS | Change in Quantitative Speech Analysis (2) | Loudness (maximum) | 0.218 dB | Standard Error 0.083 |
| Bilateral STN-DBS | Change in Quantitative Speech Analysis (2) | Loudness (minimum) | 0.003 dB | Standard Error 0.048 |
| Asymmetric STN-DBS 1 | Change in Quantitative Speech Analysis (2) | Loudness (minimum) | 0.549 dB | Standard Error 0.783 |
| Asymmetric STN-DBS 1 | Change in Quantitative Speech Analysis (2) | Loudness (maximum) | 0.619 dB | Standard Error 0.745 |
| Asymmetric STN-DBS 2 | Change in Quantitative Speech Analysis (2) | Loudness (minimum) | 0.138 dB | Standard Error 0.783 |
| Asymmetric STN-DBS 2 | Change in Quantitative Speech Analysis (2) | Loudness (maximum) | -0.003 dB | Standard Error 0.745 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.487Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.861Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.411Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.997Mixed Models Analysis
Secondary
Change in Quantitative Speech Analysis (3)
Changes in jitter measured in percentage by the Praat software. In this case, jitter is the percentage change in the stability of the frequency of speech tone (i.e. speech cycle-to-cycle frequency variation)
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Quantitative Speech Analysis (3) | 1.263 percentage change in speech tone freq. | Standard Error 0.275 |
| Asymmetric STN-DBS 1 | Change in Quantitative Speech Analysis (3) | 0.135 percentage change in speech tone freq. | Standard Error 0.155 |
| Asymmetric STN-DBS 2 | Change in Quantitative Speech Analysis (3) | 0.063 percentage change in speech tone freq. | Standard Error 0.155 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.388Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.684Mixed Models Analysis
Secondary
Change in Quantitative Speech Analysis (4)
Changes in shimmer measured in percentage by the Praat software. In this case, shimmer is the percentage change in the stability of the amplitude of speech tone (i.e. speech cycle-to-cycle amplitude variation)
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Bilateral STN-DBS | Change in Quantitative Speech Analysis (4) | 0.630 percentage change in speech tone amplit. | Standard Error 0.144 |
| Asymmetric STN-DBS 1 | Change in Quantitative Speech Analysis (4) | -0.095 percentage change in speech tone amplit. | Standard Error 0.498 |
| Asymmetric STN-DBS 2 | Change in Quantitative Speech Analysis (4) | 0.185 percentage change in speech tone amplit. | Standard Error 0.498 |
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.85Mixed Models Analysis
Comparison: Bilateral (baseline) values are the average of the outcome measure data obtained during the 2 bilateral (baseline) conditions: 1) at enrollment before randomization and 2) after randomization. These average values are used to compare the changes associated with the 2 asymmetric conditions.p-value: 0.712Mixed Models Analysis
Secondary
Change in Select Cognitive Tasks
Left brain cognitive function: Hopkins Verbal Learning Test-Revised: Total recall trials 1-3 (0-36), delayed recall (0-12); Phonemic Verbal Fluency (0-no max); Semantic Verbal Fluency (Animal cue) (0-no max); Letter 1-back and 2-back working memory tasks (0-100%). Right brain cognitive function: Brief Visual Memory Test-Revised: Total recall trials 1-3 (0-36), delayed recall (0-12); Computerized landmark line bisection (-10 to 10); Spatial 1-back and 2-back working memory tasks (0-100%). Ranges in parentheses. Line bisection: closer to 0 is more accurate. For the rest: higher values are better
Time frame: Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)
Population: Two patients could not complete cognitive tasks due to language barrier.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Bilateral STN-DBS | Change in Select Cognitive Tasks | HopkinsVerbalLearningTest-Revised: RecallTrials1-3 | -0.30 units on a scale | Standard Deviation 3.81 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Letter 1-Back Working Memory Task | 2.74 units on a scale | Standard Deviation 16.46 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | HopkinsVerbal LearningTest-Revised: Delayed Recall | -0.45 units on a scale | Standard Deviation 2.04 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Phonemic Verbal Fluency | 2.00 units on a scale | Standard Deviation 7.05 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Spatial 2-Back Working Memory Task | 0.16 units on a scale | Standard Deviation 21.92 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Computerized landmark line bisection task | 0.05 units on a scale | Standard Deviation 0.6 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Brief Visual Memory Test-Revised: Delayed Recall | 1.05 units on a scale | Standard Deviation 2.39 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Letter 2-Back Working Memory Task | 3.06 units on a scale | Standard Deviation 17.35 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Brief Visual Memory Test-Revised: RecallTrials 1-3 | 3.25 units on a scale | Standard Deviation 4.55 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Spatial 1-Back Working Memory Task | -1.07 units on a scale | Standard Deviation 17.19 |
| Bilateral STN-DBS | Change in Select Cognitive Tasks | Semantic Verbal Fluency (Animal cue) | 0.05 units on a scale | Standard Deviation 6.16 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | HopkinsVerbalLearningTest-Revised: RecallTrials1-3 | 0.50 units on a scale | Standard Deviation 3.9 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | HopkinsVerbal LearningTest-Revised: Delayed Recall | -0.75 units on a scale | Standard Deviation 1.8 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Semantic Verbal Fluency (Animal cue) | 0.50 units on a scale | Standard Deviation 4.41 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Spatial 1-Back Working Memory Task | 0.31 units on a scale | Standard Deviation 9.34 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Phonemic Verbal Fluency | 2.70 units on a scale | Standard Deviation 7.26 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Letter 1-Back Working Memory Task | 4.44 units on a scale | Standard Deviation 14.3 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Letter 2-Back Working Memory Task | 0.95 units on a scale | Standard Deviation 18.98 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Brief Visual Memory Test-Revised: RecallTrials 1-3 | 3.45 units on a scale | Standard Deviation 5.4 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Brief Visual Memory Test-Revised: Delayed Recall | 1.55 units on a scale | Standard Deviation 2.86 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Computerized landmark line bisection task | 0.01 units on a scale | Standard Deviation 0.77 |
| Asymmetric STN-DBS 1 | Change in Select Cognitive Tasks | Spatial 2-Back Working Memory Task | -1.03 units on a scale | Standard Deviation 24.01 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Brief Visual Memory Test-Revised: RecallTrials 1-3 | 2.30 units on a scale | Standard Deviation 4.4 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Letter 1-Back Working Memory Task | 3.41 units on a scale | Standard Deviation 15.68 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Phonemic Verbal Fluency | 2.35 units on a scale | Standard Deviation 8.38 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Brief Visual Memory Test-Revised: Delayed Recall | 0.85 units on a scale | Standard Deviation 2.87 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | HopkinsVerbal LearningTest-Revised: Delayed Recall | -1.40 units on a scale | Standard Deviation 2.48 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Semantic Verbal Fluency (Animal cue) | 0.80 units on a scale | Standard Deviation 3.79 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | HopkinsVerbalLearningTest-Revised: RecallTrials1-3 | -0.85 units on a scale | Standard Deviation 3.95 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Spatial 2-Back Working Memory Task | 1.67 units on a scale | Standard Deviation 24.46 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Computerized landmark line bisection task | -0.02 units on a scale | Standard Deviation 0.88 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Letter 2-Back Working Memory Task | 0.71 units on a scale | Standard Deviation 16.83 |
| Asymmetric STN-DBS 2 | Change in Select Cognitive Tasks | Spatial 1-Back Working Memory Task | -5.63 units on a scale | Standard Deviation 14.65 |
p-value: >0.05Friedman test