Visuomotor Prosthetic for Paralysis
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|ClinicalTrials.gov Identifier: NCT01958086|
Recruitment Status : Recruiting
First Posted : October 8, 2013
Last Update Posted : April 13, 2022
|Condition or disease||Intervention/treatment||Phase|
|Quadriplegia||Device: Neural Communication System||Not Applicable|
The objective of the proposed research is to obtain scientific knowledge of visuomotor transformations in posterior parietal cortex (PPC) and primary motor cortex (M1) from tetraplegic subjects in a clinical trial to advance the development of neural prosthetics. We have shown in clinical trials conducted over the past 6 years that PPC can control neural prosthetics for assisting tetraplegic subjects. Other groups have concentrated on M1 and likewise find control for neural prosthetics. In our studies of PPC we have found that besides trajectory signals to move robotic limbs or control computer cursors, there are a plethora of visuomotor signals that represent intended movements of most of the body, movement goals, cognitive strategies, and even memory signals. Our central hypothesis is that PPC and M1 will encode visuomotor parameters in both similar and different ways, and that algorithms can be developed to leverage those signals from the two areas that are complimentary to improve prosthetic range and performance. Implants will be made in both M1 and PPC, enabling simultaneous recording in the same subjects, elevating concerns of comparing data from different labs collected in different individuals with different implants and different tasks.
This central hypothesis will be tested in two broad aims, for which we have substantial preliminary data. Aim 1 will examine the control of the body by the two areas. It is hypothesized that M1 will demonstrate strong specificity for the contralateral limb (implants will be made in the hand knob) whereas PPC will code movements for most of the body and on both contra and ipsilateral sides by leveraging its partially mixed encoding of parameters (subaim 1a). Whereas M1 is hypothesized to code spatial variables exclusively during attempted or imagined actions, it is hypothesized that PPC also encodes cognitive spatial variables in task appropriate reference frames (subaim 1b). In subaim 1c we will examine how multiple body parts are combined in movement representations, hypothesizing that M1 and PPC will employ a diverse set of mechanisms including linear summation, non-linear combinations, and movement suppression expressed in different ways as a function of brain area and the specific movement set.
Aim 2 will examine the temporal aspects of encoding in the two areas. In subaim 2a we will test the hypothesis that the neural dynamics during sustained periods of movement are largely unchanging in both areas. In subaim 2b we hypothesize that, during sequential movements, M1 codes only the ongoing movement whereas PPC codes both the current and subsequent movements. Finally, in subaim 2c we will examine the coding of movement speed, with the hypothesis that there are separate subspaces in both M1 and PPC for direction and speed of movement.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||2 participants|
|Intervention Model:||Single Group Assignment|
|Masking:||None (Open Label)|
|Primary Purpose:||Basic Science|
|Official Title:||Visuomotor Prosthetic for Paralysis|
|Actual Study Start Date :||October 1, 2013|
|Estimated Primary Completion Date :||April 30, 2026|
|Estimated Study Completion Date :||July 31, 2026|
Experimental: Neural Communication System
The Neural Communication System consists of two Neuroport Multi-Port Arrays, which are descried in detail in the intervention description. One Neuroport Multi-Port Array is inserted into the posterior parietal cortex, an area of the brain used in reach planning. The second Neuroport Multi-Port Array is inserted into the motor cortex, which is primarily responsible for controlling movement. The arrays are inserted and the percutaneous pedestal is attached to the skull during a surgical procedure. Following surgical recovery the subject will participate in study sessions 3-5 times per week in which they will learn to use thought to control a simple computer environment or a tablet computer.
Device: Neural Communication System
NeuroPort Arrays allow for the local recording of cerebral cortex. The Neural Communication system is primarily composed of two NeuroPort Arrays. The two arrays of one MultiPort device will be placed in the primary motor cortex for recording (Platinum-tipped electrodes); and the two arrays of the additional MultiPort device be placed in the superior parietal lobule for recording (Platinum-tipped electrodes). Each MultiPort device consists of two arrays, each with 100 electrodes in a 10 x 10 configuration, with dimensions 4 mm x 4 mm x 1.5 mm (W x H x D) or 4 mm x 4 mm x 1.0 mm, and a titanium percutaneous connector, 19 mm diameter at the base. Each MultiPort can have a total of 128 active channels (capable of transmitting neural signals to the percutaneous connector) across the two arrays. In our design, we will split active channels evenly between the two arrays resulting in 64 active channels per array.
Other Name: NeuroPort Multi-Port Array
- Subject control of a tablet computer [ Time Frame: Six years after array implantation ]Assessments will be compared with chance and previous reports of BMI efficacy using control signals derived from primary motor cortex. Computer-interface competency examination that measures the ability of the subject to control various aspects of the tablet user interface. Additionally we will measure the Quality of Life Inventory (QOLI) at regular intervals over the duration of the study. Changes in performance over time.
- Absence of infection or irritation [ Time Frame: Six years after array implantation ]
The Serious Adverse event (SAE) rate will be calculated as the number of SAEs per implant-days. The SAE rate will be continuously compared to the 1% threshold level. CT scan; inspection of patient's scalp for evidence of reddening or discharge; review of new symptoms including possible fever, headache, visual or auditory changes, or change in mood or behavior; serial neurologic exams. The condition of the area will be compared with its condition on previous visits. History will be obtained regarding new symptoms.
Neurologic exam will be compared to baseline neurologic exam
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01958086
|Contact: Ausaf Bari, MD, PhD||310-825-5111||ABari@mednet.ucla.edu|
|Contact: Emily Rosario, PhD||909.596.7733 ext 3036||ERosario@casacolina.org|
|United States, California|
|University of California Los Angeles||Recruiting|
|Los Angeles, California, United States, 90095|
|Contact: Ausaf Bari|
|California Institute of Technology||Active, not recruiting|
|Pasadena, California, United States, 91125|
|Casa Colina Centers for Rehabilitation||Recruiting|
|Pomona, California, United States, 91769|
|Contact: Emily Rosario, PhD 909-596-7733 ext 3036 firstname.lastname@example.org|
|Principal Investigator:||Richard A Andersen, PhD||California Institute of Technology|
|Principal Investigator:||Ausaf Bari, MD, PhD||University of California, Los Angeles|
|Principal Investigator:||Emily Rosario, PhD||Casa Colina Hospital and Centers for Healthcare|