Factors associated with interest in novel interfaces for upper limb prosthesis control

Background Surgically invasive interfaces for upper limb prosthesis control may allow users to operate advanced, multi-articulated devices. Given the potential medical risks of these invasive interfaces, it is important to understand what factors influence an individual’s decision to try one. Methods We conducted an anonymous online survey of individuals with upper limb loss. A total of 232 participants provided personal information (such as age, amputation level, etc.) and rated how likely they would be to try noninvasive (myoelectric) and invasive (targeted muscle reinnervation, peripheral nerve interfaces, cortical interfaces) interfaces for prosthesis control. Bivariate relationships between interest in each interface and 16 personal descriptors were examined. Significant variables from the bivariate analyses were then entered into multiple logistic regression models to predict interest in each interface. Results While many of the bivariate relationships were significant, only a few variables remained significant in the regression models. The regression models showed that participants were more likely to be interested in all interfaces if they had unilateral limb loss (p ≤ 0.001, odds ratio ≥ 2.799). Participants were more likely to be interested in the three invasive interfaces if they were younger (p < 0.001, odds ratio ≤ 0.959) and had acquired limb loss (p ≤ 0.012, odds ratio ≥ 3.287). Participants who used a myoelectric device were more likely to be interested in myoelectric control than those who did not (p = 0.003, odds ratio = 24.958). Conclusions Novel prosthesis control interfaces may be accepted most readily by individuals who are young, have unilateral limb loss, and/or have acquired limb loss However, this analysis did not include all possible factors that may have influenced participant’s opinions on the interfaces, so additional exploration is warranted.

The procedure involves filling out a survey that will take approximately 20 minutes. Your responses will be confidential and we do not collect identifying information such as your name, email address or IP address. The survey will include questions related to basic demographics, the effect of limb loss on employment, current prosthetic usage, important prosthetic characteristics, and new prosthetic technology.
To help protect your confidentiality, the survey will not contain information that will personally identify you. The results of this study will be used for scholarly purposes only and may be shared with University of Michigan representatives.
If you have any questions about the research study, please contact Dr. Gates at gatesd@umich.edu. This research has been reviewed according to the University of Michigan IRB-MED procedures for research involving human subjects.
ELECTRONIC CONSENT: Please select your choice below. Clicking on the "agree" button below indicates that: • You have read the above information • You voluntarily agree to participate • You are at least 18 years of age If you no longer wish to participate in the research study, please decline participation by clicking on the "Disagree" button. What is the level of limb loss in your right arm?
 Above the shoulder (forequarter amputation) -shoulder blade and collarbone are removed  At the shoulder (shoulder disarticulation)  Above elbow (transhumeral) -between the elbow and shoulder  At the elbow (elbow disarticulation)  Below elbow (transradial) -between the elbow and wrist  At the wrist (wrist disarticulation)  Partial hand -finger, thumb, or part of the hand below the wrist What is the level of limb loss in your left arm?
 Above the shoulder (forequarter amputation) -shoulder blade and collarbone are removed  At the shoulder (shoulder disarticulation)  Above elbow (transhumeral) -between the elbow and shoulder  At the elbow (elbow disarticulation)  Below elbow (transradial) -between the elbow and wrist  At the wrist (wrist disarticulation)  Partial hand -finger, thumb, or part of the hand below the wrist What is the level of limb loss in your arm?
 Above the shoulder (forequarter amputation) -shoulder blade and collarbone are removed  At the shoulder (shoulder disarticulation)  Above elbow (transhumeral) -between the elbow and shoulder  At the elbow (elbow disarticulation)  Below elbow (transradial) -between the elbow and wrist  At the wrist (wrist disarticulation)  Partial hand -finger, thumb, or part of the hand below the wrist What is the level of limb loss in your right leg?  At the hip (hip disarticulation)  Above the knee (transfemoral) -between the knee and hip  At the knee (knee disarticulation)  Below the knee (transtibial) -between the ankle and knee  At the ankle (ankle disarticulation)  Partial foot -toes or part of foot below ankle What is the level of limb loss in your left leg?  At the hip (hip disarticulation)  Above the knee (transfemoral) -between the knee and hip  At the knee (knee disarticulation)  Below the knee (transtibial) -between the ankle and knee  At the ankle (ankle disarticulation)  Partial foot -toes or part of foot below ankle What is the level of limb loss in your leg?  At the hip (hip disarticulation)  Above the knee (transfemoral) -between the knee and hip  At the knee (knee disarticulation)  Below the knee (transtibial) -between the ankle and knee  At the ankle (ankle disarticulation)  Partial foot -toes or part of foot below ankle Why don't you currently use an upper limb prosthesis? (check all that apply)  Equally as functional or more functional without a prosthetic device  Past devices didn't improve function  Past devices too uncomfortable  Devices not affordable  Appearance  Other (please specify) ____________________ How satisfied are you with your overall ability to do the things you would like to do?
Which types of prosthetic devices do you currently use? (check all that apply)  Passive: Similar in appearance to the non-affected arm and replaces what was lost. It provides simple aid in balancing and carrying.  Body Powered/Conventional: Operated by a harness system that is controlled by specific body movements.  Myoelectric/External Power: Powered by a battery system and is controlled by muscle activity.  Hybrid: Combines the use of body power and external power  Adaptive/Recreational: Customized for a specific function or recreational activity.
Which types of prosthetic devices do you currently use on your right arm? (check all that apply)  Passive: Similar in appearance to the non-affected arm and replaces what was lost. It provides simple aid in balancing and carrying.  Body Powered/Conventional: Operated by a harness system that is controlled by specific body movements.  Myoelectric/External Power: Powered by a battery system and is controlled by muscle activity.  Hybrid: Combines the use of body power and external power  Adaptive/Recreational: Customized for a specific function or recreational activity.
Which types of prosthetic devices do you currently use on your left arm? (check all that apply)  Passive: Similar in appearance to the non-affected arm and replaces what was lost. It provides simple aid in balancing and carrying.  Body Powered/Conventional: Operated by a harness system that is controlled by specific body movements.  Myoelectric/External Power: Powered by a battery system and is controlled by muscle activity.  Hybrid: Combines the use of body power and external power  Adaptive/Recreational: Customized for a specific function or recreational activity. Please list these activities.
The next series of questions will ask you about whether you would be willing to try new prosthetic devices or undergo surgery if you could perform certain functions. Not all of these devices are currently available to the public.
When considering each device or procedure, please: Focus on the capabilities of the device and risks of the procedure, rather than the potential monetary cost. Assume the device is appropriate for your level of amputation (even if the picture does not show your level of amputation). Assume you have no medical restrictions that would prevent you from using the device. Assume the device is waterproof and looks similar to a real arm.
Myoelectric Device Controlled by Muscles in the Arm Device Description: This device has sensors embedded in the socket of the prosthesis that touch your skin. The sensors detect electric signals that are produced when you contract your muscles. These electric signals are used to control movement of the prosthesis.
Medical Procedure: This device requires no surgery to use.

Surgery that Moves Nerves into Different Muscles
Device Description: This device operates like the myoelectric device described previously, except that you will need to have a surgical procedure before you can use it. In this procedure, the nerves that originally controlled your amputated limb are moved and connected to muscles that have not been amputated. As a result, these muscles will contract if you attempt to move your missing limb. Sensors in the prosthesis detect electric signals from these contractions and these signals are used to control movement of the prosthesis.
Medical Procedure: The nerves are moved with a surgical procedure that requires making incisions in the arm. This procedure requires a hospital stay of about 1-3 days. The incision area will heal in about 2 weeks and become unnoticeable. After the surgery, you must wait 5-6 months to allow the nerves to regrow before you can begin training with the device.
Training Time: About 1 month.
Potential Risks: There is about a 2-3% risk of a minor medical problem (such as bruising) and a small risk of a major complication.
** This device is not currently available to the public.
With the procedure and risks in mind, how likely are you to have the device if it could let you: Wireless Device Implanted in the Arm Device Description: This device is an array of 16 small sensors implanted in the arm. During a surgical procedure, small pieces of muscle are connected to the nerves that originally controlled your amputated limb. Sensors are then wrapped around these nerves and muscles. The sensors detect electric signals that are produced if you attempt to move your missing limb. These electric signals are used to control movement of the prosthesis.
Medical Procedure: This device is put in with a surgical procedure that requires opening incisions on the arm. This procedure requires a hospital stay of about 1 day. The incision area will heal in about 2 weeks and become unnoticeable.
Training Time: About 1 week.
Potential Risks: There is about a 2-3% risk of a minor medical problem (such as bruising or infection) and a small risk of a major complication. There is a small risk that additional surgery would be required to repair breakages in the system. Wireless Device Implanted in the Brain Device Description: This device is an array of 100 tiny sensors in a package about the size of a baby aspirin. The sensors are placed 1.5 mm into the surface of the brain. The device senses brain cells firing and transmits this information to a prosthetic limb.
Medical Procedure: This device is put into the brain with a surgical procedure that requires opening the skull. Before surgery, hair around the incision area must be shaved. This procedure requires a hospital stay of about 3 days. The incision area will heal in about 2 weeks and the hair will regrow, making it unnoticeable.
Training Time: About 1 week.
Potential Risks: There is about a 3-5% risk of a minor problem (such as post-operative confusion) and a 1% risk of a major complication (such as a bleed or infection).
** This device is not currently available to the public.
With the procedure and risks in mind, how likely are you to have the device if it could let you: Thank you for your participation in this survey! We encourage you to include any additional comments in the space below.
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