Enhancing Abilities in Amputees and Patients With Peripheral Neuropathy Through Restoration of Sensory Feedback

Study Overview
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Brief Summary
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Many amputees suffer from Phantom Limb Pain (PLP), a condition where painful perceptions arise from the missing limb. Leg amputees wear prostheses that do not provide any sensory feedback, apart from the stump-socket interaction. Increased physical effort associated with prosthesis use as well as discomfort often lead to rejection of artificial limbs. Additionally, the perception of the missing limb and its brain representation, do not match-up with what amputees see (the prosthesis) and this is made worse by the absence of sensory feedback. Therefore, re-establishing the sensory flow of information between the subject's brain and the prosthetic device is extremely important to avoid this mismatch, which creates inadequate embodiment. This study focuses on improving functional abilities and decreasing PLP in amputees thanks to the use of a system able to generate a sensory feedback (SF), which will be provided with a non-invasive electrical stimulation (ES). First, the possibility of enhancing the performance in different functional tasks thanks to the use of SF will be explored. Furthermore, it will be evaluated if SF enhances the prosthesis embodiment and helps restoring a multisensory integration (visuo-tactile), potentially providing also a pain relief. Once tested this system on amputees, also people with peripheral neuropathy and sensory loss will be recruited. Diabetic patients can suffer from symmetrical polyneuropathy (DSPN), which is a common complication caused by prolonged glucose unbalanced levels that lead to nerve damage. Non-invasive ES has been proposed and used as a therapy to treat the chronic pain conditions. In particular, TENS (transcutaneous electrical nerve stimulation) is a type of non-invasive ES, which is able to activate large diameter afferent fibers. The gate control theory of pain states that these large diameter fibers inhibit central nociceptive transmission with a resultant decrease in pain perception. Therefore, also these patients will be recruited to see whether adding a non-invasive SF can enhance their functional motor abilities while diminishing their pain. The subjects will perform a pool of the following tasks, depending on their residual abilities: motor tasks (walking on ground level and on stairs), cognitive tasks (dual tasks), subjective evaluation of prosthesis weight and description of sensations from ES. Some tasks will be performed in Virtual Reality environments with and without an active stimulation.

Official Title
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Enhancing Functional and Cognitive Performances in People With Amputation and Peripheral Neuropathy Through the Restoration of Sensory Feedback in Real World and Virtual Reality Environments

Conditions
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Lower Limb Amputation Knee, Lower Limb Amputation Above Knee (Injury), Lower Limb Amputation Below Knee (Injury), Diabetic Peripheral Neuropathy

Intervention / Treatment
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* Device: Sensory Feedback


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: transfemoral amputation or transtibial amputation or knee disarticulation or diabetic peripheral neuropathy the subject should be healthy other than the amputation and the diabetic neuropathy and in the range of 18-70 years old the subject should be able to comfortably walk, sit and stand alone Exclusion Criteria: cognitive impairment pregnancy Prior or current psychological diseases such as borderline, schizophrenia, Depression or Maniac Depression acquired brain injury with residual impairment excessive sensitivity or pain to electrical stimulation with surface electrodes cybersickness

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: experimental group<br>amputees or diabetics receiving intervention | Device: Sensory Feedback<br>* Subjects will receive a sensory feedback provided by electrical stimulation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in Visual Analogue scale for pain throughout the study | Subjects will complete VAS scale to measure pain level (from 0 to 10, 10 is worst pain immaginable) | one month before the study, 2 weeks before the study, immediately before the intervention, immediately after the intervento, after tasks with and without sensory feedback, 2 weeks after last intervention, 1 month after last intervention | 
| Change between tasks with sensory feedback and with no sensory feedback in Ground Reaction Forces | GRF will be assessed during motor perfomances of the subjects | during motor tasks up to 3 weeks | 
| Change between tasks with sensory feedback and with no sensory feedback in Centre of Mass and Pressure | CoM and CoP will be assessed during motor perfomances of the subjects | during motor tasks up to 3 weeks | 
| Change from baseline and between tasks with sensory feedback and with no sensory feedback in Vo2 consumption | metabolic consumption is going to be measured with mobile spiroergometry and compared after walking with and without sensory feedback | during motor tasks up to 3 weeks | 
| Change from baseline between tasks with sensory feedback and with no sensory feedback in Embodiment | Embodiment will be measured with questionnaires (from -3 to +3, +3 totally agrees; two questions are from 1 to 10 (to measure vividness, where 10 is max vividness) and from 1 to 100 (to measure prevalence, where 100 is max duration of the embodiment feeling)) | immediately after sessions up to 3 weeks | 
| Change between tasks with sensory feedback and with no sensory feedback in Visual Analogue scale for confidence | Subjects will complete VAS scale to measure confidence level (from 0 to 10, where 10 is max confidence) | immediately after sessions up to three weeks | 
| Change between tasks with sensory feedback and with no sensory feedback in Joint torque | kinematic measurement | during motor tasks up to three weeks | 
| Change in Proprioceptive drift between different conditions | To measure embodiment subjects will be asked after VR sessions to indicate where they feel their leg without looking at the limb in real world. This is a measure of embodiment. | Immediately after sessions in Virtual Reality up to three weeks | 
| Change in Telescoping measures between different conditions | To measure embodiment subjects will be asked after VR sessions to indicate how long they feel their leg without looking at the limb in real world. This is a measure of embodiment. | Immediately after sessions in Virtual Reality up to three weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Trinity Amputation and Prosthesis Experiences Scales | Subjects will fill the TAPES to measure their satisfaction with the prosthesis (Scores range from 5 to 25, with higher scores indicating greater levels of adjustment) | Immediately before intervention | 
| Change in Quality of Life in Neurological Disorders | QoL will be assessed through questionnaires to see if the intevention had impact on this aspect (All Neuro-QOL banks and scales are scored such that a high score reflects more of what is being measured) | one week before first session and one week after last session | 
| Amputee Mobility Predictor | Subjects will perform AMPRO to assess K level (scores range from 0 to 47, correspoding to levels of mobility from 1(K1) to 4(K4), where 4 is the best level of mobility) | Immediately before the intervention |