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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
22
Asymmetric deep brain stimulation
Movement disorders Centre, Toronto Western Hospital
Toronto, Ontario, Canada
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)
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)
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)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)