Parkinson Disease
Conditions
Brief summary
Continuous deep brain stimulation (cDBS) is an established therapy for the major motor signs in Parkinson's disease, however some patients find that it does not adequately treat their freezing of gait (FOG). Currently, cDBS is limited to open-loop stimulation,without real-time adjustment to the patient's state of activity, fluctuations and types of motor symptoms, medication dosages, or neural markers of the disease. The purpose of this study is to determine if an adaptive DBS system,responding to patient specific, clinically relevant neural or kinematic feedback related to FOG, is more effective than continuous DBS on the motor Unified Parkinson's Disease Rating Scale (UPDRS III) and gait measures of PD.
Interventions
DEVICEActiva PC+S Neurostimulator
Activa PC+S Neurostimulator is approved for both aDBS and cDBS paradigms.
Sponsors
Stanford University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
1. A diagnosis of idiopathic Parkinson's disease, with bilateral symptoms at Hoehn and Yahr Stage greater than or equal to II. 2. Documented improvement in motor signs on versus off dopaminergic medication, with a change in the Unified Parkinson's Disease Rating Scale motor (UPDRS III) score of \>= 30% off to on medication. 3. The presence of complications of medication such as wearing off signs,fluctuating responses and/or dyskinesias, and/or medication refractory tremor,and/or impairment in the quality of life on or off medication due to these factors. 4. Subjects should be on stable doses of medications, which should remain unchanged until the DBS system is activated. After the DBS system is optimized(during which time the overall medication dose may be reduced to avoid discomfort and complications such as dyskinesias) the medication dose should remain unchanged, if possible, for the duration of the study. 5. Treatment with carbidopa/levodopa, and with a dopamine agonist at the maximal tolerated doses as determined by a movement disorders neurologist. 6. Ability and willingness to return for study visits, at the initial programming and after three, six and twelve months of DBS. 7. Age \> 18 8. Has a history of and/or displays freezing of gait
Exclusion criteria
1. Subjects with significant cognitive impairment and/or dementia as determined bya standardized neuropsychological battery. 2. Subjects with clinically active depression, defined according to the Diagnostic and Statistical manual of Mental Disorders, Fourth Edition (DSM-IV) criteria and as scored on a validated depression assessment scale. 3. Subjects with very advanced Parkinson's disease, Hoehn and Yahr stage 5 on medication (non-ambulatory). 4. Age \> 80. 5. Subjects with an implanted electronic device such as a neurostimulator, cardiac pacemaker/defibrillator or medication pump. 6. Subjects, who are pregnant, are capable of becoming pregnant, or who are breast feeding. 7. Patients with cortical atrophy out of proportion to age or focal brain lesions that could indicate a non-idiopathic movement disorder as determined by MRI 8. Subjects having a major comorbidity increasing the risk of surgery (prior stroke,severe hypertension, severe diabetes, or need for chronic anti-coagulation other than aspirin). 9. Subjects having any prior intracranial surgery. 10. Subjects with a history of seizures. 11. Subjects, who are immunocompromised. 12. Subjects with an active infection. 13. Subjects, who require diathermy, electroconvulsive therapy (ECT), or transcranial magnetic stimulation (TMS) to treat a chronic condition. 14. Subjects, who have an inability to comply with study follow-up visits or study protocol. 15. Subjects, who are unable to understand or sign the informed consent.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] Related to aDBS | 30 min - 2 hours | Safety, tolerability and feasibility of aDBS |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Aim 1: Alpha Power | 30 minutes | Subthalamic nucleus (STN) local field potentials (LFP) recordings demonstrate oscillatory neuronal activity in both the alpha (8-12 Hz) and beta (13-30 Hz) bands in the resting state in PD. Spectrograms were generated using a short-time Fourier transform, with a 1 second Hanning window and a 0.5 second overlap, creating a frequency resolution of 1 Hz. Power spectral densities were calculated using the Welch method with the same window and overlap parameters. Power was summed in the beta and alpha bands. This power can be representative of the magnitude of oscillatory activity in this frequency band occurring in this brain region. |
| Aim 1: Beta Power | 30 minutes | Subthalamic nucleus (STN) local field potentials (LFP) recordings demonstrate oscillatory neuronal activity in both the alpha (8-12 Hz) and beta (13-30 Hz) bands in the resting state in PD. Spectrograms were generated using a short-time Fourier transform, with a 1 second Hanning window and a 0.5 second overlap, creating a frequency resolution of 1 Hz. Power spectral densities were calculated using the Welch method with the same window and overlap parameters. Power was summed in the beta and alpha bands. This power can be representative of the magnitude of oscillatory activity in this frequency band occurring in this brain region. |
| Aim 1: Alpha Sample Entropy | 30 minutes | The predictability of the local field potentials (band-pass filtered between 8-12 Hz for alpha) was analyzed using Sample Entropy (SampEn), a nonlinear measure suitable for physiological time series. SampEn may be a more consistent measure and more suitable to shorter time series data than approximate entropy, partially due to the elimination of counting self matches. SampEn is calculated as the negative logarithm of the estimated conditional probability that if consecutive subseries of length m are similar according to some preset tolerance r, the consecutive subseries of length m+1 will be similar too. Here the length of the vector pairs, m, denotes the embedding dimension. |
| Aim 1: Beta Sample Entropy | 30 minutes | The predictability of the local field potentials (band-pass filtered between 15-30 Hz for beta) was analyzed using Sample Entropy (SampEn), a nonlinear measure suitable for physiological time series. SampEn may be a more consistent measure and more suitable to shorter time series data than approximate entropy, partially due to the elimination of counting self matches. SampEn is calculated as the negative logarithm of the estimated conditional probability that if consecutive subseries of length m are similar according to some preset tolerance r, the consecutive subseries of length m+1 will be similar too. Here the length of the vector pairs, m, denotes the embedding dimension. |
| Aim 2: Asymmetry | 30 minutes | Asymmetry during both forward walking and stepping in place was calculated using periods of walking or stepping when the subject was not freezing. According to previous studies, asymmetry is defined as: 100\*(absolute value of the natural log of the shorter average swing time over the longer average swing time) or mathematically: 100\*\| ln (SSWT/LSWT) \| where SSWT = shorter mean swing time LSWT = longer mean swing time |
| Aim 2: Arrhythmicity | 30 minutes | Arrhythmicity during both forward walking and stepping in place was calculated using periods of walking or stepping when the subject was not freezing. According to previous studies, arrhythmicity is defined as the mean stride time coefficient of variation of both legs, and a greater stride time CV implies less rhythmic gait or stepping. Higher arrhythmicity corresponds to more arrhythmic, or more impaired, gait. |
| Aim 2: Stride Time | 30 minutes | Kinematic Features associated with Freezing of Gait |
| Aim 2: Percent Time Freezing | 30 minutes | Freezing of gait episodes during stepping in place were identified using a validated computerized algorithm, and during forward walking by a blinded rater. The percent time freezing was calculated by dividing the time spent freezing by the total time to complete the task then multiplying by 100 to get a percent. If no freezing was observed, then the percent time freezing reported was 0.0%. |
| Percent Time Freezing | 30 minutes | Freezing of gait episodes during stepping in place were identified using a validated computerized algorithm. The percent time freezing was calculated by dividing the time spent freezing by the total time to complete the task then multiplying by 100 to get a percent. If no freezing was observed, then the percent time freezing reported was 0.0%. The percent time spent freezing was compared while the participant was doing the stepping in place task on continuous deep brain stimulation (cDBS) and while the participant was doing the stepping in place task on adaptive deep brain stimulation (aDBS). |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Activa PC+S Neurostimulator All patients | 12 |
| Total | 12 |
Baseline characteristics
| Characteristic | Activa PC+S Neurostimulator |
|---|---|
| Age, Continuous | 62.27 years STANDARD_DEVIATION 7.07 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 11 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 1 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 | 11 Participants |
| Sex: Female, Male Female | 5 Participants |
| Sex: Female, Male Male | 7 Participants |
| Unified Parkinson's Disease Rating Scale III Score (OFF) | 34.8 units on a scale STANDARD_DEVIATION 14.8 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 12 | 0 / 12 | 0 / 1 |
| other Total, other adverse events | 0 / 12 | 0 / 12 | 0 / 1 |
| serious Total, serious adverse events | 0 / 12 | 0 / 12 | 0 / 1 |
Outcome results
Primary
Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] Related to aDBS
Safety, tolerability and feasibility of aDBS
Time frame: 30 min - 2 hours
Population: Due to limitations in technology and resources we were only able to test a single participant during the stepping in place task while on continuous DBS and while on adaptive DBS.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] Related to aDBS | 0 Number of Treatment Emergent AEs |
| (cDBS) Activa PC+S Neurostimulator | Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] Related to aDBS | 0 Number of Treatment Emergent AEs |
| (aDBS) Activa PC+S Neurostimulator | Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] Related to aDBS | 0 Number of Treatment Emergent AEs |
Secondary
Aim 1: Alpha Power
Subthalamic nucleus (STN) local field potentials (LFP) recordings demonstrate oscillatory neuronal activity in both the alpha (8-12 Hz) and beta (13-30 Hz) bands in the resting state in PD. Spectrograms were generated using a short-time Fourier transform, with a 1 second Hanning window and a 0.5 second overlap, creating a frequency resolution of 1 Hz. Power spectral densities were calculated using the Welch method with the same window and overlap parameters. Power was summed in the beta and alpha bands. This power can be representative of the magnitude of oscillatory activity in this frequency band occurring in this brain region.
Time frame: 30 minutes
Population: Subjects were classified as a Freezer or Non-Freezer by the clinical history of a subject's symptoms and/or if the subject displayed freezing behavior pre-operatively or during the tasks.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 1: Alpha Power | Stepping in Place Task | 0.845 arbitrary units (power) | Standard Deviation 0.543 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Alpha Power | Forward Walking | 1.710 arbitrary units (power) | Standard Deviation 1.28 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Alpha Power | Turning and Barrier Course | 1.393 arbitrary units (power) | Standard Deviation 0.901 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Alpha Power | Stepping in Place Task | 1.051 arbitrary units (power) | Standard Deviation 0.511 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Alpha Power | Forward Walking | 2.753 arbitrary units (power) | Standard Deviation 3.261 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Alpha Power | Turning and Barrier Course | 1.890 arbitrary units (power) | Standard Deviation 1.351 |
Secondary
Aim 1: Alpha Sample Entropy
The predictability of the local field potentials (band-pass filtered between 8-12 Hz for alpha) was analyzed using Sample Entropy (SampEn), a nonlinear measure suitable for physiological time series. SampEn may be a more consistent measure and more suitable to shorter time series data than approximate entropy, partially due to the elimination of counting self matches. SampEn is calculated as the negative logarithm of the estimated conditional probability that if consecutive subseries of length m are similar according to some preset tolerance r, the consecutive subseries of length m+1 will be similar too. Here the length of the vector pairs, m, denotes the embedding dimension.
Time frame: 30 minutes
Population: Subjects were classified as a Freezer or Non-Freezer by the clinical history of a subject's symptoms and/or if the subject displayed freezing behavior pre-operatively or during the tasks.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 1: Alpha Sample Entropy | Stepping in Place Task | 0.251 arbitrary units | Standard Deviation 0.002 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Alpha Sample Entropy | Forward Walking | 0.248 arbitrary units | Standard Deviation 0.007 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Alpha Sample Entropy | Turning and Barrier Course | 0.253 arbitrary units | Standard Deviation 0.003 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Alpha Sample Entropy | Stepping in Place Task | 0.253 arbitrary units | Standard Deviation 0.004 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Alpha Sample Entropy | Forward Walking | 0.247 arbitrary units | Standard Deviation 0.007 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Alpha Sample Entropy | Turning and Barrier Course | 0.250 arbitrary units | Standard Deviation 0.004 |
Secondary
Aim 1: Beta Power
Subthalamic nucleus (STN) local field potentials (LFP) recordings demonstrate oscillatory neuronal activity in both the alpha (8-12 Hz) and beta (13-30 Hz) bands in the resting state in PD. Spectrograms were generated using a short-time Fourier transform, with a 1 second Hanning window and a 0.5 second overlap, creating a frequency resolution of 1 Hz. Power spectral densities were calculated using the Welch method with the same window and overlap parameters. Power was summed in the beta and alpha bands. This power can be representative of the magnitude of oscillatory activity in this frequency band occurring in this brain region.
Time frame: 30 minutes
Population: Subjects were classified as a Freezer or Non-Freezer by the clinical history of a subject's symptoms and/or if the subject displayed freezing behavior pre-operatively or during the tasks.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 1: Beta Power | Stepping in Place Task | 4.085 arbitrary units (power) | Standard Deviation 2.077 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Beta Power | Forward Walking | 9.143 arbitrary units (power) | Standard Deviation 6.835 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Beta Power | Turning and Barrier Course | 7.321 arbitrary units (power) | Standard Deviation 4.429 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Beta Power | Stepping in Place Task | 11.258 arbitrary units (power) | Standard Deviation 8.493 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Beta Power | Forward Walking | 8.400 arbitrary units (power) | Standard Deviation 5.529 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Beta Power | Turning and Barrier Course | 6.993 arbitrary units (power) | Standard Deviation 0.207 |
Secondary
Aim 1: Beta Sample Entropy
The predictability of the local field potentials (band-pass filtered between 15-30 Hz for beta) was analyzed using Sample Entropy (SampEn), a nonlinear measure suitable for physiological time series. SampEn may be a more consistent measure and more suitable to shorter time series data than approximate entropy, partially due to the elimination of counting self matches. SampEn is calculated as the negative logarithm of the estimated conditional probability that if consecutive subseries of length m are similar according to some preset tolerance r, the consecutive subseries of length m+1 will be similar too. Here the length of the vector pairs, m, denotes the embedding dimension.
Time frame: 30 minutes
Population: Subjects were classified as a Freezer or Non-Freezer by the clinical history of a subject's symptoms and/or if the subject displayed freezing behavior pre-operatively or during the tasks.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 1: Beta Sample Entropy | Stepping in Place Task | 0.407 arbitrary units | Standard Deviation 0.031 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Beta Sample Entropy | Forward Walking | 0.380 arbitrary units | Standard Deviation 0.05 |
| (OFF) Activa PC+S Neurostimulator | Aim 1: Beta Sample Entropy | Turning and Barrier Course | 0.377 arbitrary units | Standard Deviation 0.05 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Beta Sample Entropy | Stepping in Place Task | 0.337 arbitrary units | Standard Deviation 0.062 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Beta Sample Entropy | Forward Walking | 0.376 arbitrary units | Standard Deviation 0.053 |
| (cDBS) Activa PC+S Neurostimulator | Aim 1: Beta Sample Entropy | Turning and Barrier Course | 0.376 arbitrary units | Standard Deviation 0.052 |
Secondary
Aim 2: Arrhythmicity
Arrhythmicity during both forward walking and stepping in place was calculated using periods of walking or stepping when the subject was not freezing. According to previous studies, arrhythmicity is defined as the mean stride time coefficient of variation of both legs, and a greater stride time CV implies less rhythmic gait or stepping. Higher arrhythmicity corresponds to more arrhythmic, or more impaired, gait.
Time frame: 30 minutes
Population: 12 participants total: the 8 freezers are the same participants across stimulation conditions; the 4 non-freezers are the same participants across stimulation conditions.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 2: Arrhythmicity | Stepping in Place Task | 54.04 arrythmicity (CV%) | Standard Deviation 50.46 |
| (OFF) Activa PC+S Neurostimulator | Aim 2: Arrhythmicity | Forward Walking | 6.76 arrythmicity (CV%) | Standard Deviation 3.29 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Arrhythmicity | Stepping in Place Task | 27.49 arrythmicity (CV%) | Standard Deviation 33.23 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Arrhythmicity | Forward Walking | 5.18 arrythmicity (CV%) | Standard Deviation 2.25 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Arrhythmicity | Stepping in Place Task | 29.34 arrythmicity (CV%) | Standard Deviation 56.18 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Arrhythmicity | Forward Walking | 6.41 arrythmicity (CV%) | Standard Deviation 2.68 |
| Non-Freezers (OFF Stim) | Aim 2: Arrhythmicity | Forward Walking | 5.98 arrythmicity (CV%) | Standard Deviation 4.37 |
| Non-Freezers (OFF Stim) | Aim 2: Arrhythmicity | Stepping in Place Task | 4.01 arrythmicity (CV%) | Standard Deviation 0.81 |
| Non-Freezers (60 Hz Stim) | Aim 2: Arrhythmicity | Forward Walking | 4.96 arrythmicity (CV%) | Standard Deviation 1.35 |
| Non-Freezers (60 Hz Stim) | Aim 2: Arrhythmicity | Stepping in Place Task | 4.10 arrythmicity (CV%) | Standard Deviation 1.4 |
| Non-Freezers (140 Hz Stim) | Aim 2: Arrhythmicity | Forward Walking | 4.94 arrythmicity (CV%) | Standard Deviation 1.38 |
| Non-Freezers (140 Hz Stim) | Aim 2: Arrhythmicity | Stepping in Place Task | 4.00 arrythmicity (CV%) | Standard Deviation 0.73 |
Secondary
Aim 2: Asymmetry
Asymmetry during both forward walking and stepping in place was calculated using periods of walking or stepping when the subject was not freezing. According to previous studies, asymmetry is defined as: 100\*(absolute value of the natural log of the shorter average swing time over the longer average swing time) or mathematically: 100\*\| ln (SSWT/LSWT) \| where SSWT = shorter mean swing time LSWT = longer mean swing time
Time frame: 30 minutes
Population: 12 participants total: the 8 freezers are the same participants across stimulation conditions; the 4 non-freezers are the same participants across stimulation conditions. Subjects were classified Freezer/Non-Freezer by the clinical history of a subject's symptoms and/or if the subject displayed freezing behavior pre-operatively or during the tasks.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 2: Asymmetry | Stepping in Place Task | 26.74 asymmetry (%) | Standard Deviation 23.44 |
| (OFF) Activa PC+S Neurostimulator | Aim 2: Asymmetry | Forward Walking | 6.11 asymmetry (%) | Standard Deviation 4.11 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Asymmetry | Stepping in Place Task | 27.1 asymmetry (%) | Standard Deviation 21.42 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Asymmetry | Forward Walking | 5.01 asymmetry (%) | Standard Deviation 2.97 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Asymmetry | Stepping in Place Task | 15.99 asymmetry (%) | Standard Deviation 12.12 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Asymmetry | Forward Walking | 4.52 asymmetry (%) | Standard Deviation 3.39 |
| Non-Freezers (OFF Stim) | Aim 2: Asymmetry | Stepping in Place Task | 9.54 asymmetry (%) | Standard Deviation 6.87 |
| Non-Freezers (OFF Stim) | Aim 2: Asymmetry | Forward Walking | 3.32 asymmetry (%) | Standard Deviation 1.88 |
| Non-Freezers (60 Hz Stim) | Aim 2: Asymmetry | Stepping in Place Task | 7.86 asymmetry (%) | Standard Deviation 7.1 |
| Non-Freezers (60 Hz Stim) | Aim 2: Asymmetry | Forward Walking | 2.41 asymmetry (%) | Standard Deviation 2.5 |
| Non-Freezers (140 Hz Stim) | Aim 2: Asymmetry | Stepping in Place Task | 7.25 asymmetry (%) | Standard Deviation 9.03 |
| Non-Freezers (140 Hz Stim) | Aim 2: Asymmetry | Forward Walking | 4.50 asymmetry (%) | Standard Deviation 2.23 |
Secondary
Aim 2: Percent Time Freezing
Freezing of gait episodes during stepping in place were identified using a validated computerized algorithm, and during forward walking by a blinded rater. The percent time freezing was calculated by dividing the time spent freezing by the total time to complete the task then multiplying by 100 to get a percent. If no freezing was observed, then the percent time freezing reported was 0.0%.
Time frame: 30 minutes
Population: 12 participants total: the 8 freezers are the same participants across stimulation conditions; the 4 non-freezers are the same participants across stimulation conditions.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 2: Percent Time Freezing | Stepping in Place Task | 29.37 % time freezing | Standard Deviation 38.27 |
| (OFF) Activa PC+S Neurostimulator | Aim 2: Percent Time Freezing | Forward Walking | 0.17 % time freezing | Standard Deviation 0.48 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Percent Time Freezing | Stepping in Place Task | 11.01 % time freezing | Standard Deviation 29.57 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Percent Time Freezing | Forward Walking | 0.0 % time freezing | Standard Deviation 0 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Percent Time Freezing | Stepping in Place Task | 18.13 % time freezing | Standard Deviation 34.58 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Percent Time Freezing | Forward Walking | 0.0 % time freezing | Standard Deviation 0 |
| Non-Freezers (OFF Stim) | Aim 2: Percent Time Freezing | Stepping in Place Task | 0.0 % time freezing | Standard Deviation 0 |
| Non-Freezers (OFF Stim) | Aim 2: Percent Time Freezing | Forward Walking | 0.0 % time freezing | Standard Deviation 0 |
| Non-Freezers (60 Hz Stim) | Aim 2: Percent Time Freezing | Stepping in Place Task | 0.0 % time freezing | Standard Deviation 0 |
| Non-Freezers (60 Hz Stim) | Aim 2: Percent Time Freezing | Forward Walking | 0.0 % time freezing | Standard Deviation 0 |
| Non-Freezers (140 Hz Stim) | Aim 2: Percent Time Freezing | Stepping in Place Task | 0.0 % time freezing | Standard Deviation 0 |
| Non-Freezers (140 Hz Stim) | Aim 2: Percent Time Freezing | Forward Walking | 0.0 % time freezing | Standard Deviation 0 |
Secondary
Aim 2: Stride Time
Kinematic Features associated with Freezing of Gait
Time frame: 30 minutes
Population: 12 participants total: the 8 freezers are the same participants across stimulation conditions; the 4 non-freezers are the same participants across stimulation conditions.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Aim 2: Stride Time | Stepping in Place Task | 1.71 seconds | Standard Deviation 0.68 |
| (OFF) Activa PC+S Neurostimulator | Aim 2: Stride Time | Forward Walking | 1.14 seconds | Standard Deviation 0.19 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Stride Time | Stepping in Place Task | 1.44 seconds | Standard Deviation 0.53 |
| (cDBS) Activa PC+S Neurostimulator | Aim 2: Stride Time | Forward Walking | 1.11 seconds | Standard Deviation 0.15 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Stride Time | Stepping in Place Task | 1.21 seconds | Standard Deviation 0.44 |
| (aDBS) Activa PC+S Neurostimulator | Aim 2: Stride Time | Forward Walking | 1.10 seconds | Standard Deviation 0.14 |
| Non-Freezers (OFF Stim) | Aim 2: Stride Time | Stepping in Place Task | 1.07 seconds | Standard Deviation 0.15 |
| Non-Freezers (OFF Stim) | Aim 2: Stride Time | Forward Walking | 1.16 seconds | Standard Deviation 0.06 |
| Non-Freezers (60 Hz Stim) | Aim 2: Stride Time | Stepping in Place Task | 1.05 seconds | Standard Deviation 0.14 |
| Non-Freezers (60 Hz Stim) | Aim 2: Stride Time | Forward Walking | 1.15 seconds | Standard Deviation 0.07 |
| Non-Freezers (140 Hz Stim) | Aim 2: Stride Time | Stepping in Place Task | 1.06 seconds | Standard Deviation 0.17 |
| Non-Freezers (140 Hz Stim) | Aim 2: Stride Time | Forward Walking | 1.18 seconds | Standard Deviation 0.1 |
Secondary
Percent Time Freezing
Freezing of gait episodes during stepping in place were identified using a validated computerized algorithm. The percent time freezing was calculated by dividing the time spent freezing by the total time to complete the task then multiplying by 100 to get a percent. If no freezing was observed, then the percent time freezing reported was 0.0%. The percent time spent freezing was compared while the participant was doing the stepping in place task on continuous deep brain stimulation (cDBS) and while the participant was doing the stepping in place task on adaptive deep brain stimulation (aDBS).
Time frame: 30 minutes
Population: Due to limitations in technology and resources we were only able to test a single participant during the stepping in place task while on continuous DBS and while on adaptive DBS.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| (OFF) Activa PC+S Neurostimulator | Percent Time Freezing | 44 % time freezing | Standard Deviation 0 |
| (cDBS) Activa PC+S Neurostimulator | Percent Time Freezing | 2 % time freezing | Standard Deviation 0 |
| (aDBS) Activa PC+S Neurostimulator | Percent Time Freezing | 0 % time freezing | Standard Deviation 0 |