Dystonia, Essential Tremor, Parkinson Disease
Conditions
Keywords
Deep Brain Stimulation (DBS), ventralis intermedius nucleus (VIN), implantable pulse generator (IPG), Diffusion Tensor Imaging (DTI)
Brief summary
This project aims to investigate novel ways to deliver brain stimulation to Essential Tremor (ET) patients by introducing software changes to their existing devices. The study team aims to investigate safety and efficacy of these new stimulation parameters in patients with ET.
Detailed description
Deep brain stimulation (DBS) is a neuromodulatory therapy that is effective in a subset of well selected essential tremor (ET) patients. However, as many as 1/5 of patients may initially improve, but then steadily worsen following the operation. The investigators developed a technique to study a variety of alternative stimulation methods without the use of an invasive repeat surgical intervention. The electrophysiological effects of non-conventional DBS differ from traditional DBS, however the physiological differences in the setting of human tremor remain largely unknown. This study plans to explore gaps in knowledge of neuromodulation and will collect and contribute essential information to the underlying mechanism of action of DBS. The hypothesis of this project centers around active biphasic stimulation providing a wider therapeutic window and a lower adverse event profile as compared to conventional DBS.
Interventions
DEVICEActive biphasic pulse stimulation---Home Settings
During this visit, the DBS implantable pulse generator (IPG) will be loaded with a temporary custom firmware to allow implementation of active biphasic pulse stimulation.
DEVICEActive biphasic pulse stimulation---VIN Biphasic
During this visit, the DBS implantable pulse generator (IPG) will be loaded with a temporary custom firmware to allow implementation of active biphasic pulse stimulation.
DEVICEActive biphasic pulse stimulation---Stimulator Off
During this visit, the DBS implantable pulse generator (IPG) will be loaded with a temporary custom firmware to allow implementation of active biphasic pulse stimulation.
Sponsors
University of Florida
National Institute of Neurological Disorders and Stroke (NINDS)
Medtronic
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Masking description
Each of the 3 interventions will be videotaped for blinded motor score assessment by an independent rater.
Intervention model description
Patients with chronically implanted DBS devices for ET who experience progressive worsening of tremor symptoms over time.
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Existing unilateral or bilateral VIN DBS for ET, non-demented (MMSE\>24), and must have a documented suboptimal tremor suppression on two successive visits (compared to the baseline post-operative improvement at 6 months following ET DBS surgery). For bilateral cases, the most affected tremor side will be studied.
Exclusion criteria
* No diagnosis of Essential Tremor
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fiber Activation Threshold From Stimulation With ET DBS | 4 hours | The study team will use computer simulation and virtual reconstruction of the brain from pre-operative MRI data to calculate the fiber activation threshold for the duration that each subject is on the home settings versus the biphasic settings. The investigators will assess the feasibility of the patterns to address the worsening of ET that may occur in 20% or more of the ET population. No fiber activation threshold data was collected for the DBS OFF state since the system was not active. |
| Home Settings DBS Versus Active Biphasic Pulse DBS Settings | 4 hours | The investigators will compare the degree of tremor suppression from the home settings versus active biphasic DBS. The degree of tremor will be quantified by the Fahn-Tolosa-Marin Tremor Rating Scale (sum of motor score parts A and B; range 0 - 116). A higher Tremor Rating Scale score is associated with more severe motor symptoms. The clinical metrics represent the change from DBS OFF to the active arm (either home settings or biphasic VIN) after 4 hours of stimulation |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Tremor Motor Physiology | 4 hour | Essential tremor motor physiology will be recorded by the Kinesia ONE accelerometer system. The Kinesia ONE system utilizes a wireless, wearable motion sensor and portable transducer to translate movement metrics into a tremor severity score ranging from 0 (no symptoms) to 4 (severe symptoms). In this study, the reported tremor severity score represents motor function captured after 4 hours of active DBS - under either the participants' home settings or the VIN biphasic configuration. |
| Gait Impairment - Step Length | 4 hours | Essential tremor's effect on gait will be assessed by the GAITRite system. Patients will walk along a GAITRite floor mat to have the various gait parameters such as step length measured. The GAITRite system translates movement metrics into an objective kinematic score. In this study, the reported kinematic scores represent motor function captured after 4 hours of active DBS - under either the participants' home settings or the VIN biphasic configuration. |
| Gait Impairment - Stride Length | 4 hours | Essential tremor's effect on gait will be assessed by the GAITRite system. Patients will walk along a GAITRite floor mat to have the various gait parameters such as stride length measured. The GAITRite system translates movement metrics into an objective kinematic score. In this study, the reported kinematic scores represent motor function captured after 4 hours of active DBS - under either the participants' home settings or the VIN biphasic configuration. |
| Gait Impairment - Step Time | 4 hours | Essential tremor's effect on gait will be assessed by the GAITRite system. Patients will walk along a GAITRite floor mat to have the various gait parameters such as step time measured. The GAITRite system translates movement metrics into an objective kinematic score. In this study, the reported kinematic scores represent motor function captured after 4 hours of active DBS - under either the participants' home settings or the VIN biphasic configuration. |
| Gait Impairment - Gait Cycle Time | 4 hours | Essential tremor's effect on gait will be assessed by the GAITRite system. Patients will walk along a GAITRite floor mat to have the various gait parameters such as gait cycle time measured. The GAITRite system translates movement metrics into an objective kinematic score. In this study, the reported kinematic scores represent motor function captured after 4 hours of active DBS - under either the participants' home settings or the VIN biphasic configuration. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORJoshua K Wong, MD
Univeristy of Florida
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Continuous | 71.1 Years STANDARD_DEVIATION 6.7 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 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 | 12 Participants |
| Region of Enrollment United States | 12 Participants |
| Sex: Female, Male Female | 7 Participants |
| Sex: Female, Male Male | 5 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 6 | 0 / 6 |
| other Total, other adverse events | 0 / 6 | 0 / 6 |
| serious Total, serious adverse events | 0 / 6 | 0 / 6 |
Outcome results
None listed