Trial Outcomes & Findings for Asymmetric Subthalamic Deep Brain Stimulation for Axial Motor Dysfunction in Parkinson's Disease (NCT NCT03462082)

NCT ID: NCT03462082

Last Updated: 2021-01-05

Results Overview

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.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

22 participants

Primary outcome timeframe

Baseline and 3 to 4 weeks after switching to each of the DBS conditions (Bilateral, Asymmetric 1, Asymmetric 2)

Results posted on

2021-01-05

Participant Flow

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.

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.

Participant milestones

Participant milestones
Measure
Bilateral DBS Then Asymmetric DBS 1 Then Asymmetric DBS 2
Baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Bilateral DBS Then Asymmetric DBS 2 Then Asymmetric DBS 1
Baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Asymmetric DBS 1 Then Bilateral DBS Then Asymmetric DBS 2
Asymmetric STN-DBS 1 (right STN amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Asymmetric DBS 1 Then Asymmetric DBS 2 Then Bilateral DBS
Asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks.
Asymmetric DBS 2 Then Bilateral DBS Then Asymmetric DBS 1
Asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Asymmetric DBS 2 Then Asymmetric DBS 1 Then Bilateral DBS
Asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks.
Asymmetric DBS 1 (Open Label)
After the Study Phase (Randomized, Blinded Period) was completed, patients were offered to participate in an Open Label Phase in which they would be switched for at least 12 weeks to either the Asymmetric DBS 1 or the Asymmetric DBS 2 condition if it was associated with axial symptom improvement when compared to their baseline bilateral DBS condition. Out of the 22 patients initially enrolled, 17 opted to participate. Out of the 17 patients that opted to participate, 7 were switched to the Asymmetric DBS 1 condition: 50% reduction of right STN-DBS amplitude (voltage)
Asymmetric DBS 2 (Open Label)
After the Study Phase (Randomized, Blinded Period) was completed, patients were offered to participate in an Open Label Phase in which they would be switched for at least 12 weeks to either the Asymmetric DBS 1 or the Asymmetric DBS 2 condition if it was associated with axial symptom improvement when compared to their baseline bilateral DBS condition. Out of the 22 patients initially enrolled, 17 opted to participate. Out of the 17 patients that opted to participate, 10 were switched to the Asymmetric DBS 2 condition: 50% reduction of left STN-DBS amplitude (voltage)
Study Phase (Randomized, Blinded Period)
STARTED
3
4
4
3
3
5
0
0
Study Phase (Randomized, Blinded Period)
COMPLETED
3
4
4
3
3
5
0
0
Study Phase (Randomized, Blinded Period)
NOT COMPLETED
0
0
0
0
0
0
0
0
Open Label Phase
STARTED
0
0
0
0
0
0
7
10
Open Label Phase
COMPLETED
0
0
0
0
0
0
6
8
Open Label Phase
NOT COMPLETED
0
0
0
0
0
0
1
2

Reasons for withdrawal

Reasons for withdrawal
Measure
Bilateral DBS Then Asymmetric DBS 1 Then Asymmetric DBS 2
Baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Bilateral DBS Then Asymmetric DBS 2 Then Asymmetric DBS 1
Baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Asymmetric DBS 1 Then Bilateral DBS Then Asymmetric DBS 2
Asymmetric STN-DBS 1 (right STN amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Asymmetric DBS 1 Then Asymmetric DBS 2 Then Bilateral DBS
Asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks.
Asymmetric DBS 2 Then Bilateral DBS Then Asymmetric DBS 1
Asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks.
Asymmetric DBS 2 Then Asymmetric DBS 1 Then Bilateral DBS
Asymmetric STN-DBS 2 (left STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by asymmetric STN-DBS 1 (right STN-DBS amplitude reduced by 50%) for 3 to 4 weeks, followed by baseline bilateral STN-DBS for 3 to 4 weeks.
Asymmetric DBS 1 (Open Label)
After the Study Phase (Randomized, Blinded Period) was completed, patients were offered to participate in an Open Label Phase in which they would be switched for at least 12 weeks to either the Asymmetric DBS 1 or the Asymmetric DBS 2 condition if it was associated with axial symptom improvement when compared to their baseline bilateral DBS condition. Out of the 22 patients initially enrolled, 17 opted to participate. Out of the 17 patients that opted to participate, 7 were switched to the Asymmetric DBS 1 condition: 50% reduction of right STN-DBS amplitude (voltage)
Asymmetric DBS 2 (Open Label)
After the Study Phase (Randomized, Blinded Period) was completed, patients were offered to participate in an Open Label Phase in which they would be switched for at least 12 weeks to either the Asymmetric DBS 1 or the Asymmetric DBS 2 condition if it was associated with axial symptom improvement when compared to their baseline bilateral DBS condition. Out of the 22 patients initially enrolled, 17 opted to participate. Out of the 17 patients that opted to participate, 10 were switched to the Asymmetric DBS 2 condition: 50% reduction of left STN-DBS amplitude (voltage)
Open Label Phase
Symptom worsening (Treatment failure)
0
0
0
0
0
0
1
2

Baseline Characteristics

Two patients could not complete cognitive tasks due to language barrier.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
All Study Participants
n=22 Participants
All Study Participants
Age, Continuous
65.5 years
n=22 Participants
Sex: Female, Male
Female
7 Participants
n=22 Participants
Sex: Female, Male
Male
15 Participants
n=22 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
0 Participants
n=22 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
22 Participants
n=22 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants
n=22 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=22 Participants
Race (NIH/OMB)
Asian
5 Participants
n=22 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=22 Participants
Race (NIH/OMB)
Black or African American
0 Participants
n=22 Participants
Race (NIH/OMB)
White
17 Participants
n=22 Participants
Race (NIH/OMB)
More than one race
0 Participants
n=22 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
n=22 Participants
Region of Enrollment
Canada
22 Participants
n=22 Participants
Hand dominance
82.5 units on a scale
n=22 Participants
Parkinson's disease duration
17 years
n=22 Participants
Predominant motor symptom at onset
Tremor
9 Participants
n=22 Participants
Predominant motor symptom at onset
Stiffness and/or Slowness
13 Participants
n=22 Participants
More affected hemibody at onset
Right
13 Participants
n=22 Participants
More affected hemibody at onset
Left
8 Participants
n=22 Participants
More affected hemibody at onset
Both
1 Participants
n=22 Participants
Indication for STN-DBS surgery
Medication-resistant tremor
8 Participants
n=22 Participants
Indication for STN-DBS surgery
Medication-resistant motor fluctuations
14 Participants
n=22 Participants
Time since STN-DBS surgery
51 months
n=22 Participants
Time between STN-DBS surgery and onset of axial dysfunction
14.5 months
n=22 Participants
More affected hemibody at enrollment
Right
4 Participants
n=22 Participants
More affected hemibody at enrollment
Left
4 Participants
n=22 Participants
More affected hemibody at enrollment
Both
14 Participants
n=22 Participants
Levodopa equivalent daily dose
1037.5 mg/day
n=22 Participants
Baseline right STN-DBS type
Conventional monopolar
1 Participants
n=22 Participants
Baseline right STN-DBS type
Low-frequency monopolar
8 Participants
n=22 Participants
Baseline right STN-DBS type
High-frequency monopolar
3 Participants
n=22 Participants
Baseline right STN-DBS type
Interleaving low-frequency monopolar
4 Participants
n=22 Participants
Baseline right STN-DBS type
Double low-frequency monopolar
1 Participants
n=22 Participants
Baseline right STN-DBS type
Interleaving low-frequency monopolar/double monop.
1 Participants
n=22 Participants
Baseline right STN-DBS type
Conventional bipolar
1 Participants
n=22 Participants
Baseline right STN-DBS type
Low-frequency bipolar
2 Participants
n=22 Participants
Baseline right STN-DBS type
High-frequency bipolar
0 Participants
n=22 Participants
Baseline right STN-DBS type
Interleaving conventional monopolar / bipolar
1 Participants
n=22 Participants
Baseline right STN-DBS amplitude
3.95 Volts
n=22 Participants
Baseline right STN-DBS frequency
80 Hertz
n=22 Participants
Baseline right STN-DBS pulse width
60 Microseconds
n=22 Participants
Baseline total electrical energy delivered (TEED) to the right STN
88.59 Joules/second
n=22 Participants
Baseline left STN-DBS type
Conventional monopolar
0 Participants
n=22 Participants
Baseline left STN-DBS type
Low-frequency monopolar
8 Participants
n=22 Participants
Baseline left STN-DBS type
High-frequency monopolar
1 Participants
n=22 Participants
Baseline left STN-DBS type
Interleaving low-frequency monopolar
4 Participants
n=22 Participants
Baseline left STN-DBS type
Double low-frequency monopolar
0 Participants
n=22 Participants
Baseline left STN-DBS type
Interleaving low-frequency monopolar/double monop.
1 Participants
n=22 Participants
Baseline left STN-DBS type
Conventional bipolar
2 Participants
n=22 Participants
Baseline left STN-DBS type
Low-frequency bipolar
3 Participants
n=22 Participants
Baseline left STN-DBS type
High-frequency bipolar
2 Participants
n=22 Participants
Baseline left STN-DBS type
Interleaving conventional monopolar / bipolar
1 Participants
n=22 Participants
Baseline left STN-DBS amplitude
4.08 Volts
n=22 Participants
Baseline left STN-DBS frequency
80 Hertz
n=22 Participants
Baseline left STN-DBS pulse width
60 Microseconds
n=22 Participants
Baseline total electrical energy delivered (TEED) to the left STN
89.66 Joules/second
n=22 Participants
Gait velocity
0.976 m/s
n=22 Participants
MDS-UPDRS (total)
89 units on a scale
n=22 Participants
MDS-UPDRS (motor)
45.5 units on a scale
n=22 Participants
MDS-UPDRS (axial motor)
16.5 units on a scale
n=22 Participants
Mini-BESTest score
15 units on a scale
n=22 Participants
UPDRS-PIGD score
11 units on a scale
n=22 Participants
Freezing of gait questionnaire
14.5 units on a scale
n=22 Participants
Summary index of the PDQ-39
31.54 units on a scale
n=22 Participants
Select cognitive tasks
HopkinsVerbalLearningTest-Revised: RecallTrials1-3
21.75 units on a scale
STANDARD_DEVIATION 5.78 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
HopkinsVerbal LearningTest-Revised: Delayed Recall
7.70 units on a scale
STANDARD_DEVIATION 2.56 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Phonemic Verbal Fluency
31.50 units on a scale
STANDARD_DEVIATION 14.15 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Semantic Verbal Fluency (Animal cue)
16.80 units on a scale
STANDARD_DEVIATION 7.82 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Letter 1-Back Working Memory Task
82.86 units on a scale
STANDARD_DEVIATION 18.51 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Letter 2-Back Working Memory Task
55.11 units on a scale
STANDARD_DEVIATION 26.28 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Brief Visual Memory Test-Revised: RecallTrials 1-3
12.75 units on a scale
STANDARD_DEVIATION 6.24 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Brief Visual Memory Test-Revised: Delayed Recall
5.15 units on a scale
STANDARD_DEVIATION 3.38 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Computerized landmark line bisection task
0.08 units on a scale
STANDARD_DEVIATION 0.53 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Spatial 1-Back Working Memory Task
85.20 units on a scale
STANDARD_DEVIATION 23.22 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.
Select cognitive tasks
Spatial 2-Back Working Memory Task
57.81 units on a scale
STANDARD_DEVIATION 29.10 • n=20 Participants • Two patients could not complete cognitive tasks due to language barrier.

PRIMARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Gait Velocity
0.941 m/s
Standard Error 0.086
-0.069 m/s
Standard Error 0.048
-0.016 m/s
Standard Error 0.048

SECONDARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Motor Function
MDS-UPDRS (total)
1.032 units on a scale
Standard Error 0.093
10.058 units on a scale
Standard Error 4.491
1.277 units on a scale
Standard Error 4.491
Change in Motor Function
MDS-UPDRS (motor)
1.080 units on a scale
Standard Error 0.086
4.582 units on a scale
Standard Error 2.147
1.636 units on a scale
Standard Error 2.147
Change in Motor Function
MDS-UPDRS (axial motor)
0.947 units on a scale
Standard Error 0.074
-1.342 units on a scale
Standard Error 0.823
-2.453 units on a scale
Standard Error 0.823

SECONDARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Axial Motor Function (1)
0.967 units on a scale
Standard Error 0.068
-0.017 units on a scale
Standard Error 0.828
1.557 units on a scale
Standard Error 0.828

SECONDARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Axial Motor Function (2)
0.909 units on a scale
Standard Error 0.153
-0.549 units on a scale
Standard Error 0.704
-1.414 units on a scale
Standard Error 0.704

SECONDARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Axial Motor Function (3)
0.837 units on a scale
Standard Error 0.088
-0.056 units on a scale
Standard Error 0.807
-1.888 units on a scale
Standard Error 0.807

SECONDARY outcome

Timeframe: 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.

Changes in gait velocity in m/s as measured by a quantitative gait analysis system (Zeno walkway).

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quantitative Gait Analysis (1)
0.814 m/s
Standard Error 0.095
-6.635 m/s
Standard Error 3.910
-1.254 m/s
Standard Error 3.910

SECONDARY outcome

Timeframe: 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.

Changes in step length in cm (mean, right, left) as measured by a quantitative gait analysis system (Zeno walkway). Step length difference = \[right - left step length\]

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quantitative Gait Analysis (2)
Step length (mean)
0.975 cm
Standard Error 0.129
-3.097 cm
Standard Error 1.990
-3.191 cm
Standard Error 1.990
Change in Quantitative Gait Analysis (2)
Step length (right)
0.899 cm
Standard Error 0.156
-2.867 cm
Standard Error 1.931
-3.800 cm
Standard Error 1.931
Change in Quantitative Gait Analysis (2)
Step length (left)
1.015 cm
Standard Error 0.115
-3.293 cm
Standard Error 2.252
-3.493 cm
Standard Error 2.252
Change in Quantitative Gait Analysis (2)
Step length difference
0.731 cm
Standard Error 0.138
0.426 cm
Standard Error 1.088
-0.307 cm
Standard Error 1.088

SECONDARY outcome

Timeframe: 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.

Step length ratio = \[right step length\] / \[left step length\] Step length symmetry = (\[right - left step length\] / \[right + left step length\])

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quantitative Gait Analysis (3)
Step length ratio
1.214 ratio
Standard Error 0.286
-0.011 ratio
Standard Error 0.071
0.002 ratio
Standard Error 0.071
Change in Quantitative Gait Analysis (3)
Step length symmetry
0.934 ratio
Standard Error 0.19
0.421 ratio
Standard Error 2.36
-0.420 ratio
Standard Error 2.36

SECONDARY outcome

Timeframe: 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.

Changes in pitch in Hertz (Hz) as measured by the Praat software.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quantitative Speech Analysis (1)
Pitch (minimum)
0.434 Hz
Standard Error 0.242
16.864 Hz
Standard Error 7.931
1.176 Hz
Standard Error 7.931
Change in Quantitative Speech Analysis (1)
Pitch (maximum)
0.735 Hz
Standard Error 0.071
-146.413 Hz
Standard Error 78.824
-78.213 Hz
Standard Error 78.824

SECONDARY outcome

Timeframe: 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.

Changes in loudness in decibels (dB) as measured by the Praat software.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quantitative Speech Analysis (2)
Loudness (minimum)
0.003 dB
Standard Error 0.048
0.549 dB
Standard Error 0.783
0.138 dB
Standard Error 0.783
Change in Quantitative Speech Analysis (2)
Loudness (maximum)
0.218 dB
Standard Error 0.083
0.619 dB
Standard Error 0.745
-0.003 dB
Standard Error 0.745

SECONDARY outcome

Timeframe: 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.

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)

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quantitative Speech Analysis (3)
1.263 percentage change in speech tone freq.
Standard Error 0.275
0.135 percentage change in speech tone freq.
Standard Error 0.155
0.063 percentage change in speech tone freq.
Standard Error 0.155

SECONDARY outcome

Timeframe: 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.

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)

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quantitative Speech Analysis (4)
0.630 percentage change in speech tone amplit.
Standard Error 0.144
-0.095 percentage change in speech tone amplit.
Standard Error 0.498
0.185 percentage change in speech tone amplit.
Standard Error 0.498

SECONDARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=22 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=22 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=22 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Quality of Life
0.792 units on a scale
Standard Error 0.154
1.701 units on a scale
Standard Error 2.506
-3.148 units on a scale
Standard Error 2.506

SECONDARY outcome

Timeframe: 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.

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

Outcome measures

Outcome measures
Measure
Bilateral STN-DBS
n=20 Participants
Bilateral (baseline) STN-DBS settings
Asymmetric STN-DBS 1
n=20 Participants
50% reduction of right STN-DBS amplitude (voltage)
Asymmetric STN-DBS 2
n=20 Participants
50% reduction of left STN-DBS amplitude (voltage)
Change in Select Cognitive Tasks
Spatial 2-Back Working Memory Task
0.16 units on a scale
Standard Deviation 21.92
-1.03 units on a scale
Standard Deviation 24.01
1.67 units on a scale
Standard Deviation 24.46
Change in Select Cognitive Tasks
HopkinsVerbalLearningTest-Revised: RecallTrials1-3
-0.30 units on a scale
Standard Deviation 3.81
0.50 units on a scale
Standard Deviation 3.90
-0.85 units on a scale
Standard Deviation 3.95
Change in Select Cognitive Tasks
HopkinsVerbal LearningTest-Revised: Delayed Recall
-0.45 units on a scale
Standard Deviation 2.04
-0.75 units on a scale
Standard Deviation 1.80
-1.40 units on a scale
Standard Deviation 2.48
Change in Select Cognitive Tasks
Phonemic Verbal Fluency
2.00 units on a scale
Standard Deviation 7.05
2.70 units on a scale
Standard Deviation 7.26
2.35 units on a scale
Standard Deviation 8.38
Change in Select Cognitive Tasks
Semantic Verbal Fluency (Animal cue)
0.05 units on a scale
Standard Deviation 6.16
0.50 units on a scale
Standard Deviation 4.41
0.80 units on a scale
Standard Deviation 3.79
Change in Select Cognitive Tasks
Letter 1-Back Working Memory Task
2.74 units on a scale
Standard Deviation 16.46
4.44 units on a scale
Standard Deviation 14.30
3.41 units on a scale
Standard Deviation 15.68
Change in Select Cognitive Tasks
Letter 2-Back Working Memory Task
3.06 units on a scale
Standard Deviation 17.35
0.95 units on a scale
Standard Deviation 18.98
0.71 units on a scale
Standard Deviation 16.83
Change in Select Cognitive Tasks
Brief Visual Memory Test-Revised: RecallTrials 1-3
3.25 units on a scale
Standard Deviation 4.55
3.45 units on a scale
Standard Deviation 5.40
2.30 units on a scale
Standard Deviation 4.40
Change in Select Cognitive Tasks
Brief Visual Memory Test-Revised: Delayed Recall
1.05 units on a scale
Standard Deviation 2.39
1.55 units on a scale
Standard Deviation 2.86
0.85 units on a scale
Standard Deviation 2.87
Change in Select Cognitive Tasks
Computerized landmark line bisection task
0.05 units on a scale
Standard Deviation 0.60
0.01 units on a scale
Standard Deviation 0.77
-0.02 units on a scale
Standard Deviation 0.88
Change in Select Cognitive Tasks
Spatial 1-Back Working Memory Task
-1.07 units on a scale
Standard Deviation 17.19
0.31 units on a scale
Standard Deviation 9.34
-5.63 units on a scale
Standard Deviation 14.65

Adverse Events

Bilateral STN-DBS (Study Phase)

Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths

Asymmetric STN-DBS 1 (Study Phase)

Serious events: 0 serious events
Other events: 8 other events
Deaths: 0 deaths

Asymmetric STN-DBS 2 (Study Phase)

Serious events: 0 serious events
Other events: 3 other events
Deaths: 0 deaths

Asymmetric STN-DBS 1 (Open Label Phase)

Serious events: 0 serious events
Other events: 1 other events
Deaths: 0 deaths

Asymmetric STN-DBS 2 (Open Label Phase)

Serious events: 0 serious events
Other events: 2 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure
Bilateral STN-DBS (Study Phase)
n=22 participants at risk
Bilateral (baseline) STN-DBS settings (During the randomized, blinded phase)
Asymmetric STN-DBS 1 (Study Phase)
n=22 participants at risk
50% reduction of right STN-DBS amplitude (voltage) (During the randomized, blinded phase)
Asymmetric STN-DBS 2 (Study Phase)
n=22 participants at risk
50% reduction of left STN-DBS amplitude (voltage) (During the randomized, blinded phase)
Asymmetric STN-DBS 1 (Open Label Phase)
n=7 participants at risk
50% reduction of right STN-DBS amplitude (voltage) (During the open label phase)
Asymmetric STN-DBS 2 (Open Label Phase)
n=10 participants at risk
50% reduction of left STN-DBS amplitude (voltage) (During the open label phase)
Nervous system disorders
Treatment failure
0.00%
0/22 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
13.6%
3/22 • Number of events 3 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
4.5%
1/22 • Number of events 1 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
14.3%
1/7 • Number of events 1 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
20.0%
2/10 • Number of events 2 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
Nervous system disorders
Increase in levodopa equivalent daily dose
0.00%
0/22 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
22.7%
5/22 • Number of events 5 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
9.1%
2/22 • Number of events 2 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
0.00%
0/7 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.
0.00%
0/10 • Adverse event data were collected for 12-18 weeks (study duration per patient) plus at least 12 additional weeks for patients who opted for the open label phase after study completion.

Additional Information

Karlo J Lizarraga, MD, MS / Assistant Professor of Neurology

University of Rochester

Phone: 585-341-7500

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place