FLEXA
INDIVIDUAL Project | 4TH-YEAR CAPSTONE
8 MONTHS | FALL 2022 - WINTER 2023
THE CHALLENGE
The wrist is one of the most injured and cast parts of the body. Access to physical therapy, in particular Neuromuscular Electrical Stimulation (NMES), influences the success of recovery. NMES is a common method used to help regain strength and mobility after cast removal. People who have their wrist immobilized after injury or surgery often cannot access physiotherapy regularly. This leads to pain, weakness, and a lack of support in recovery.
Outcome
The opportunity exists to create a safe and effective way to heal while being connected with a therapist who can guide them through NMES rehabilitation remotely. The solution developed is an NMES device that can be lent out to patients, monitored and programmed remotely by physiotherapists through Internet of Things (IoT) integration, and allow for optimized at-home wrist rehabilitation. This device would be used to re-educate the flexor and extensor muscles of the forearm.
RESEARCH & PROBLEM UNDERSTANDING
Physiotherapy & NMES
While immobilization through the use of a cast or splint is often necessary in the early stages of recovery to promote proper healing, once removed, there is often resulting muscle atrophy, pain, and stiffness in the forearm and wrist joint. This results in a great amount of discomfort.
Physical therapy is recommended for those healing from a broken or fractured wrist to accelerate recovery. Physiotherapy is a treatment method that aims to restore, maintain, and maximize strength, function, mobility, and overall well-being of patients. However, there is a lack of access to physiotherapy services due to social, financial and systematic healthcare related barriers.
NMES is commonly used by physiotherapists to rehabilitate the upper limbs after injury. NMES works by sending electrical impulses that target muscle fibres and cause them to contract when patients may be unable to activate these muscles on their own yet, helping to rebuild the connection between the brain and muscles.
For those who have experienced wrist injury, there are a range of benefits in undergoing physiotherapy and receiving NMES, especially for wrists that have been immobilized in a cast for a long time.
NMES Devices on the Market
Many NEMS units are used in professional treatment contexts only. These are large, expensive, and often incorporate many types of electrotherapy into a singular device. NEMS units are recommended to be prescribed, however some with limited functionalities are available over the counter.
Problems with Current Devices
Challenges accompany the use of existing at-home devices.
INTRODUCING IOT
The Internet of Medical Things (IoMT) describes the growing network of medical devices communicating data between patients and healthcare providers. This creates opportunities for patient self-monitoring, remote monitoring by providers, and new opportunities for virtual consultations, thus expanding accessibility of care. With IoT integration, the use of an NMES device for the wrist could be guided and monitored remotely.
CONCEPT DEVELOPMENT
A decision made from the outset was to create a device tailored to the wrist, as opposed to a standardized device that could be used on any part of the body, as current devices are. This is due to the variability of muscles and injuries around the body. A customized device would allow a more effective, nuanced, and intuitive approach; this product could be expanded to a system of products for various body injuries.
Initial Concept
The original direction composed of a sleeve with built-in electrodes. The goal was repeatability: if the electrode placement could be tailored to the patient’s arm once, and the patient could put the sleeve on correctly every time after that, then they will always have muscle stimulation in the correct location.
Through further exploration, the idea of a self-calibrating array was developed. The proposal was that the device would know or be able to figure out which electrodes are best to use. The user defines the general placement of the array, and the array itself does the fine adjustment to find the target muscles using motion sensor as feedback in order to produce the desired movement.
Several strap and sleeve-like forms were created and tested to evaluate the objective of correct electrode positioning.
USER TESTING FINDINGS
The initial prototypes were tested on fellow peers, including ID and non-ID students to assess whether the prototypes were easy to put on and comfortable. The accuracy of electrode placement on the forearm muscles was also assessed.
INDUSTRY FEEDBACK
The above and the following prototypes were shown to a physiotherapist, senior industrial designer with healthcare experience, and biomedical scientist and engineer at Toronto Rehabilitation Institute. Feedback included that the general placement of electrodes is very learnable for patients; straps or a sleeve may not be necessary to assist with this. The fine-tuning of the electrode placement within the smaller range is the larger challenge.
PIVOT
Moving forward, due a lack of repeatabability in electrode placement when putting on the sleeve and due to its twisting, I removed the idea of a full forearm sleeve from the design. New objectives included making the control unit that powers the system as compact as possible as well as managing wires cleanly between individual components.
NEW CONCEPT: USER TESTING
When given diagrams to follow, it was easy for people to replicate the general placement of the electrodes. Following testing, the product system was simplified to one regular electrode and one array electrode, both of which are easily transferrable to either side of the arm. This reduced complexity and cost. The later addition of lights allowing users to see which electrodes in the array underneath are being activated; this came from a desire for users to better understand what the electrode array is doing as it calibrates.
Electrode Array Exploration
Control Pod: Mood Board
Control Pod: Form Exploration
Control Pod: User Testing
Users were asked which pod they preferred handling while following the product use cycle. The pods below are arranged in order of form preference. Softer edges were described as safer and more visually appealing. A slight doming of the top surface was preferred.
Sleeve: Mood Board
Sleeve: Form and Fit Exploration
Sleeve: User Testing
Findings included that velcro should be placed on the palm side of the hand. This makes the sleeve easier to put on and does not interfere with the flex sensors on the opposite side of the hand. When the material is too elastic, it becomes difficult to close the glove tight enough due to distortion. The strap length needs to accomodate different sized wrists. Minimizing the amount of material, especially on the palm side, allows for breathability and less material use in production.
FINAL DESIGN
Product System
Product Components
Accurate Electrode Placement
The electrode array simplifies the process of finding the correct muscles. The patient places the pod in the general area of the extensors and flexors, and then the device selects the best electrodes to use based on the hand movement detected. Activating the sides of the main muscle strands leads to horizontal hand deviation to the right or left during stimulation. Selecting the correct electrodes ensures the hand motion is in the path for optimal engagement.
Versatility
The device can be used on both sides of the forearm. It is placed on the palm side to strengthen the forearm flexors and on the backhand side to strengthen the extensors. Stimulating both sides of the forearm ensures balanced recovery. Flexion is shown on the left and extension is shown on the right.
Details
Use Case Scenario
Mobile Application
Information Architecture
System Map
Technical Drawings
This project was awarded the User Experience Award by Cortex Design in the ACIDO Rocket Competition. It was also awarded the George Lynn Memorial Scholarship by Carleton University.
