Regaining Strength After StrokeTailwind featured in Discoveries + Breakthroughs - 05/01/2011 Regaining Strength After Stroke Read the article ยป

History of Tailwind


Every year over 780,000 Americans have a stroke. Stroke is the leading cause of adult disability in the United States, and nearly 6 million people are living with stroke. Stroke survivors are left with effects that can impair health, bodily function, and motor skills. An estimated 1.3 million stroke survivors are left with some form of arm dysfunction after stroke. Most patients with arm paralysis are treated with different forms of rehabilitative therapy or electrical stimulation. What if there was a more effective and less costly solution?

The research team working with Encore Path, Inc. has found exactly that. In the last 2 years, this young and promising start-up company has developed the Tailwind device. This device, formerly known as the Bilateral Arm Trainer with Rhythmic Auditory Cueing, or BATRAC, was created with the purpose of improving arm function and range of motion in patients with moderate arm paralysis following stroke or other brain injury.

Starting the Development Process

Following the invention of the Tailwind device, Encore Path looked at a number of engineering firms to develop and refine the device prior to product launch. After meeting engineers from Sagentia at the Medical Device and Manufacturing (MD&M) Conference in New York in June 2006, the company decided to ask Sagentia to re-engineer the device. Sagentia had a proven track record of customer-focused design capabilities such as the Voice of the Customer (VoC) work, empathic design in previous projects, and understanding of cost considerations for a start-up company. Sagentia was very eager to help Encore Path reduce engineering costs and raise investment funds to complete the project. Sagentia also evidenced a creative approach to product design which Encore Path thought would benefit both the end-user customer and the company itself.

The purpose of the project was to create a product which Encore Path would be able to market commercially with an anticipated sales volume of several hundred units per month. The engineering team from Sagentia delivered its first proposal to Encore Path on August 24, 2006. Similar to other projects completed by Sagentia, work on the Tailwind device took place on a phase by phase basis with the end of each phase constituting a major milestone. The overall goal for Sagentia was to develop a product which represented a well-designed, lower-cost version of the initial prototype.

Sagentia’s engineering team described the initial presentation of the device as showing significant clinical development in prototype form. The BATRAC device had been produced as a ‘proof of principle’ prototype. Its component parts had been fabricated using costly ‘one-off’ machining techniques with only limited effort put toward the ergonomics, cost of goods, and assembly issues. While ideal for early stage testing, the device was not ideally suited to production in even modest numbers and not cost effective for volume manufacture.

The challenge for the engineering team was to progress the design to a form suitable for batch production and sale to rehabilitation facilities and individual stroke survivors. This required significant industrial, mechanical and electrical re-engineering and design for manufacture improvements with a view to reducing the cost of goods. Voice of the Customer research was conducted using both clinicians and end users of the device, in order to take an empathic approach to the design of the new device.

Prototype to Final Product

Almost a year to the day of the initial proposal, Sagentia delivered the final proposal for the development of the Tailwind device. The BATRAC development program proposed by Sagentia was divided into work phases. Each phase would have specific tasks, deliverables, and estimated time frames for completion. The first phase of the project was referred to as the Concept Definition Requirement Specification phase. During this initial development phase, it was important for the engineering team to assemble a comprehensive list of the intended device features and functionality. Sagentia worked with Encore Path to use this stage of the development process as a means of concept review and to understand the required product embodiments and functions. After working with Encore Path, the engineering team would be better able to determine what should be included in the new design as well as what could be added or changed in later design upgrades. The majority of the initial development phase took place at sessions in front of the prototype model and at the clinical site where the prototypes were being used. A requirement specification was then written and agreed upon with the Encore Path team and the Tailwind inventors before moving forward. At the end of the first development phase, Encore Path was presented with clinical Voice of the Customer research and hand drawn sketches of five preliminary design concepts, along with cost and risk assessments. Additionally, Sagentia delivered the final Product Requirements Specifications for the device.

Phase two of the project consisted of creating the engineering design specification. It was during this phase that final industrial design work and top level mechanical engineering was carried out. By the end of the phase, Sagentia had completed conceptual design of the Tailwind device; the search and specification for preliminary parts; and the first 3D computer-aided design model of the device. Sagentia presented Encore Path with the 3D model and photorealistic renderings to illustrate the design intent and to exhibit the final product embodiment.

The detailed design phase was the third step in the development of Tailwind. Using computer-aided design, the parts and assembly of the device were detailed to a level where parts and related tools could be ordered. The bill of materials was developed and the preliminary product cost was estimated at this time. Upon completion of phase three, considerations with respect to safety issues had been addressed.

The fourth and final stage of the development process was referred to as the Pre-production Model Phase. This segment of the engineering process consisted of the manufacturing, testing, and delivery of the prototype devices. The initial devices produced were designed for user testing and engineering evaluation prior to final design changes. The first units were fully functional tested by Sagentia against the design specification before being handed over to Encore Path for clinical testing. The first device was delivered to Encore Path on April 28, 2008.


Double Brace: Early Tailwind Prototype

Double Brace: Final Tailwind device

When asked about Encore Path’s initial reaction to the device, Paul Caron of Sagentia, Project Manager for the Tailwind, said, “When (Encore Path President) Kris came in that day she also brought one of her business advisors. Quite honestly I think it is fair to say that she was almost speechless. Her advisor was equally impressed and actually said he thought that the Tailwind had the quality look of a device designed by Apple Computer. As we worked with Kris to get acquainted with the device, she handled it as though she were handling a baby, careful not to break anything. In a way, you could see that she was seeing the results of all the work she had put forth.”

Challenges in Development

As with any project the engineering team faced certain challenges and obstacles during the design and engineering of the Tailwind device. The biggest challenge was to work from the original prototype to develop a number of new design concepts to take forward into a commercially viable product. A primary concern was the challenge of ensuring the product would be suitable for the needs of stroke survivors. When asked about these design challenges, the team responded, “In truth we probably took a slightly more radical approach to the re-design than Kris had anticipated, but her reaction was so positive to our ideas and recommendations that we continued to push limits. During this process, the unique needs of the stroke survivor remained the key driving factors for the design.”

There were occasional issues as to how best to implement a specific concept or function in the device. These issues were managed in sessions where the engineering team would consult with other Sagentia associates not specifically assigned to the job for a fresh objective look or approach to the issue. The process of developing the device took approximately two years. In that time period Encore Path and the engineering team from Sagentia were able to overcome the challenges presented during the development of the device. When asked to reflect on the challenges that were presented, Paul Caron responded, “Product development is always an iterative process, and inevitably some of the specific implementations we chose behaved differently to what we expected, it’s easy to be disappointed when this happened, but it is inevitable. Overcoming these hurdles took application and diligence on our side and faith on Kris’. It’s the name of the game.”

Reflecting on the Project

The Tailwind project required a great deal of research and time being invested during the development of the device. As with other projects, the engineering team spent countless hours understanding the device and searching for the best path forward for its development. Upon the completion of the project the Sagentia team was certainly met with a feeling of accomplishment and success.

In addition to progressing a promising invention into a sellable product, the engineering team was also effected a little more personally by the Tailwind project than by the typical project. As stated earlier, the engineering team performed voice of the customer research during the development of the device. This included working with Encore Path and the inventors of the Tailwind device, but most importantly, it included working with stroke patients. Over the life of the project, the engineering team from Sagentia worked with a number of patients during the initial design concept development and during prototype validation. Watching the stroke survivors struggle to regain a measure of control over their disabilities provided Sagentia’s engineers with a personal understanding of the difficulties that these patients live with on a daily basis. This level of personal understanding of patient needs is one offering where Sagentia adds value to the innovation process.
Double Brace: Example of stroke survivor   using Tailwind

When asked about this experience, the team replied, “It instilled in us a greater sense of purpose. It provided direction for developing a product for these patients that was easier to use and therefore would help eliminate compliance issues.” This sense of purpose made the project a little more personal for Paul Caron and the engineering team at Sagentia. Working with Encore Path to translate an exciting and promising invention into an invaluable and marketable product that could change the lives of stroke survivors is what made the project special for the engineering team. When asked about his experiences with the Tailwind project, Paul Caron said, “Having seen firsthand how a stroke affects a patient’s daily life gave us a much greater sense of purpose in designing a product that could so positively affect their life.”