Functional and Neuroprotective Effects of Restoring Lower Limb Sensation After Diabetic Peripheral Neuropathy

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to evaluate the effectiveness of providing sensation of the missing limb to individuals with above and below the knee limb loss. The investigators will implanted stimulating electrodes to send small electrical currents to the remaining nerves. These small electrical currents cause the nerves to generate signals that are then transferred to your brain similar to how the information about your foot and lower limb used to be transferred to the brain prior to your limb loss. Additionally, there is the option to have muscle recording electrodes implanted within the muscles of the lower limb with the goal to develop a motor controller that would allow the user to have intuitive control of a robotic prosthetic leg.

Detailed Description
-----------------
Electrodes are surgically implanted on one to four nerves of the residual limb. Intramuscular recording electrodes can be implanted in the lower limbs and hip muscles in order to obtain electromyography (EMG) signals. The EMG recordings will be used to develop an algorithm which can operate an advanced robotic prosthesis in which the prosthesis joint(s) movements could be controlled. An external wearable stimulation device controls the delivery of electrical pulses to the implanted system. An instrumented prosthesis will be developed such that perceived sensations would correspond to prosthesis interactions with the floor. The instrumented prosthesis will be worn while the participant is engaging in various functional tasks, such as standing, walking or climbing stairs or with visual or mental distractions.

Official Title
-----------------
Functional and Neuroprotective Effects of Restoring Lower Limb Sensation After Diabetic Peripheral Neuropathy

Conditions
-----------------
Lower Extremity Amputee, Diabetic Peripheral Neuropathy

Intervention / Treatment
-----------------
* Device: Implanted Multi contact stimulating electrode and intramuscular electromyography recording electrode


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Chronic, medically stable lower limb amputation due to diabetes or insensate foot due to Diabetic peripheral neuropathy Being ambulatory and ability to stand or walk with prosthesis or orthosis Viable target nerves in the lower extremity as determined by standard-of-care clinical tests of nerve conduction, response to stimulation, sensory evoked potentials (SEP) and the like Good skin integrity and personal hygiene Absence of autoimmune deficiencies, seizure disorders or cardiac abnormalities contraindicating stimulation Sufficient social support and personal ability to tolerate study procedures and comply with follow-up schedule Exclusion Criteria: Active pressure ulcers or chronic skin ulcerations Uncontrolled diabetes with HbA1c greater than or equal to 69 mmol/mol (8.5%) Significant vascular disease Significant history of poor wound healing Significant history of uncontrolled infections Active infection Significant pain in the foot, residual or phantom limb Pregnancy Inability to speak English: The study design requires the subject to communicate and describe the elicited sensations in their lower limb History of vestibular or movement disorders that would compromise balance or walking Class II or III obesity (Body Mass Index > 35) Uncontrolled depression, psychoses or cognitive impairments. Subjects with unstable mental illness or severe cognitive impairments may be unable to comply with a long term study schedule Expectation that MRI will be required at any point for the duration of study or while percutaneous leads are in place. At this time MRI is contraindicated, subjects who require regular MRI should not enroll Arthritis in the area of implant- Inflammation or stiffness in the area of implant could limit placement of the electrodes

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Device Feasibility
Intervention Model: Single Group Assignment
Interventional Model Description: The project will take the form of a series of controlled single-subject feasibility and proof-of-concept studies with repeated measures. Subjects will act as their own concurrent controls with and without sensory stimulation, as well as their own longitudinal (historical) controls pre- and post-implementation of the Sensory Neuroprosthesis.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Multi contact electrode implant and implanted electromyography recording electrodes<br>Fifteen subjects with lower limb amputation will receive implanted multicontact stimulating nerve cuff electrodes connected to temporary percutaneous leads. During experimental testing, a small amount of stimulation will be applied to the nerves through the contacts of the multichannel cuff electrode. | Device: Implanted Multi contact stimulating electrode and intramuscular electromyography recording electrode<br>* See arm description<br>* Other names: Sensory Neuroprosthesis;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stimulation thresholds | Quantify the minimum stimulation required to evoke electrically induced sensations on the phantom limb. | 9 months post implant | 
| Functional Gait Assessment (FGA) | The Functional Gait Assessment is a 10 task test that measures postural stability. Each task is scored from 0 -3 with 0 indicating severe impairment in the task and 3 indicating normal ambulation. The scores are combined to give a total score. The maximum score is 30. A higher score indicates a better outcome. | 6 months post implant | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neuropathic Pain Syndrome Inventory (NPSI) | The NPSI is comprised of five subscales, each representing different dimensions of neuropathic pain: burning spontaneous pain (burning), pressing spontaneous pain (pressing), paroxysmal pain (paroxysmal), evoked pain (evoked), and paresthesia/dysesthesia Each area subscale is scored between 0-10. The scores are not combined, but are able to report on different aspects of neuropathic pain. A higher score indicates a worse outcome. | 4 years post implant | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Sensory Feedback, Limb Loss, Prosthesis User