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What’s Next for the iPhone ECG Following Regulatory Clearance?

What’s Next for the iPhone ECG Following Regulatory Clearance?

After recently winning FDA clearance and CE Mark certification, the iPhone ECG from AliveCor (San Francisco, CA), is poised to kickstart a disruption of the traditional ECG market. The device, although not intended to replace traditional 12-lead ECG testing, is making heart monitoring technology more pervasive and mobile. “Our aspiration is that the ECG should be as accessible to you as your blood pressure,” said the company’s president and CEO Judy Wade in an interview with MD+DI. “Our vision overall is that everyone should have their health at their fingertips. And by everyone, we mean globally everyone.”

Cardiovascular disease remains the leading cause of death globally, according to the World Health Organization, and 82% of those deaths occur in low- and middle-income countries. In many of these countries, many people never or rarely visit a doctor. Nevertheless, three quarters of the world’s population already has access to cell phones.

At present, the company is focusing first on the domestic market. iPhone ECG is available for U.S. medical (and veterinary) professionals on the iPhone 4 and 4S. The unit consists of a case with two electrodes on the back that detect ECG data and convert it to ultrasonic FM sound signals that are transmitted to the microphone of the iPhone. New form factors that can accommodate other types of mobile devices are in the works.

“Our goal is to make this technology universally available for the prescription use as well as for over-the-counter use,” Wade says. “In January, we’ll announce the timing of both of those next steps.” Commercializing an over-the-counter consumer version will require that FDA approves a 510(k) filed for that application.

The above image was drawn from a teardown report for the AliveCor Veterinary Heart Monitor AC-002. The case for this unit is identical to the human version, which recently obtained regulatory clearance. The monitor consists of two electrodes that come in contact with the patient's skin in order to obtain the ECG waveform. As the TechInsights report explains, the output ECG signals from the device are converted to ultrasonic FM sound signals that are transmitted through an audio transmitter to the microphone of the iPhone, where it is processed and displayed by the iPhone.

The company already has a veterinary product available in Europe; a human version will be made available for that market in 2013. Wade says the technology’s low cost and the fact that the information it generates is stored in the cloud bode well for its global adoption.

As is the case with many disruptive technologies, the iPhone ECG has attracted both adulation and skepticism; so far, the former has predominated. The device has won endorsements from famous clinicians such as Eric Topol, MD; Leslie Saxon, MD; and NIH chief Francis Collins, MD. High-profile investors Vinod Khosla and G. Steven Burrill are also fond of the device, sometimes showing it off in public.The unit has been validated in a clinical study against the Mac5500 12-lead ECG from GE Healthcare.

But for all the buzz surrounding the device, it has attracted some skepticism as well. For instance, an over-the-top Gizmodo piece pokes fun at the notion of a doctor using an iPhone to check a patient's heart health. On MedCity news, a mostly positive piece by Westby G. Fisher, MD, acknowledges the potential challenges that lie ahead in “deploying this device on the general public.”

Similar dialogue has surrounded many disruptive innovations, which as Harvard Business School professor and author Clayton Christensen has explained, are initially characterized by lower performance than that of the broader market. For instance, when the cell phone debuted, it had worse sound quality than either landlines or payphones. As the sound quality and functionality of the devices greatly improved and the price dropped, payphones have nearly become extinct and use of landlines is plummeting.

That’s not to say the iPhone ECG will eventually make the 12-lead ECG obsolete. But as Dr. Fisher points out in the aforementioned article, “for doctors and medically-savvy patients, this device is a game-changer.” The device is substantially less expensive and easier to use than conventional ECG devices and, at $199, the iPhone ECG is a fraction of the cost of a traditional ECG unit. Because of those factors, it makes way for the doctors who own the device to use it in public locations such as airplanes and shopping malls. In fact, the device has already been used in the former scenario. In November 2011, Topol used the device to diagnose a myocardial infarction while on a plane en route from Virginia to San Diego. The plane made an emergency landing and the patient survived the ordeal.

AliveCor is also exploring algorithm-based ECG detection technology that could be validated by a physician to more accurately detect atrial fibrillation (AF), which dramatically elevates the risk of stroke. In a recent study titled “Validation of an iPhone ECG Application Suitable for Community Screening for Silent Atrial Fibrillation: A Novel Way to Prevent Stroke,” the automated algorithm had an accuracy of 97%. The study concluded that the device could have “a substantial impact on reducing ischemic stroke related to previously undiagnosed AF.” Wades explains that using algorithms in conjunction with the mobile ECG technology is “evidence of [the company’s] aspiration overall.”

The field of computer-assisted diagnosis, which has existed for decades, is picking up steam.

The field of computer-assisted diagnosis, which has existed for decades, is picking up steam. IBM is working to harness the Watson artificial intelligence computer system's ability to understand natural language, solve complex problems, and continually learn from massive data sets to improve diagnoses. Only recently, Silicon Valley-based startup Scanadu announced its plans to commercialize a trio of home diagnostic devices.

The field of smartphone-based automated ECG interpretation is also gaining momentum. Last year, the PhysioNet/Computing in Cardiology Challenge was announced to develop an ECG algorithm that can run in near real-time on a smartphone and provide diagnostic information that could be understood by a layperson.

Wade says she is excited by the long-term prospects of recording and analyzing peoples’ ECGs. “What we see is our ability to take deep data around electrocardiograms that we can contextualize with user behavior data,” Wade says. She explains that the system to do this would be HIPPAA-compliant and would synthesize ECG and other health metrics and clinical trial data to “provide deep insight and services for cardiac health.” Such a system could be used, for instance, to determine what is triggering an arrhythmia or to observe the heart growing stronger over time in response to exercise.

The company also plans to partner with Saxon to develop the project, an online network that will store medical data harnessed from smartphones. “We see Leslie Saxon as a key partner and we are absolutely excited to contribute and working with her on that overall vision of,” she says.

Brian Buntz is the editor-at-large at UBM Canon's medical group. Follow him on Twitter at @brian_buntz

For more on the iPhone ECG, check out the “Ahead of His Time” series of MD+DI articles:

This Week in Devices [12/7/2012]: FDA Partners with Device Industry; Final Rules for the Medical Device Tax

This Week in Devices [12/7/2012]

FDA announces a partnership with the device industry to speed up device innovation. The IRS has released the final rules for the medical device tax. Certain plastics may be unsuitable for device implants. A brain pacemaker for Alzheimer's.

FDA Partnership to Speed Up Industry
With so much criticism thrown its way in regards to timeliness and efficiency, FDA can often seem like a whipping boy for the device industry. But, to the agency's credit, it is always working to resolve this. This week FDA announced that it will partner with the industry group, Medical Device Innovation Consortium, on a public-private partnership aimed at speeding up the development of new medical technology. [CBS News]

IRS Releases Final Rules for Medical Device Tax
With the medical device tax set to take effect in mere weeks the IRS has released its final rules for the new 2.3% tax. The tax is purported to raise $29 billion in revenue through 2022. However this does not mean companies have stopped lobbying against the tax for the burden it will lay on device makers. [Reuters]
Plastics used in some medical devices, including those that keep the heart beating regularly, can break down in a previously unrecognized way.
Credit: iStockphoto/Thinkstock
Study Shows Some Plastics Are a Poor Choice for Devices
Silicon-urethane plastics are often used in medical devices including implantable devices like pacemakers. However a new study by the American Chemical Society has found that these materials can begin to break down in as little as 3-6 years when exposed to water. Previous studies have only looked at how these compounds break down with oxygen exposure, but these new findings could lead to new considerations and developments in device design. [ACS]

A Brain Pacemaker for Alzheimer's Disease
The latest development in deep brain stimulation came as John Hopkins University researchers have announced that they have successfully surgically implanted a pacemaker-like device into the brain of a patient in the early stages of Alzheimer's disease. The device, which uses electrical stimulation within the brain, has been used to treat Parkinson's disease and has been suggested in the treatment of maajor depression and Tourette syndrome. Researchers are hoping it will provide a viable treatment for Alzheimer's patients. [Medical News Today]

MobileCare Monitor by AFrame Receives FDA Clearance

AFrame Digital, a medical device manufacturer based in Reston, Virginia, received clearance from the United States Food and Drug Administration (FDA) for its MobileCare monitoring system. The Class II approval of the device follows Class I approval by the FDA in 2009. According to a press release by the company, the MobileCare health monitor uses a specialized wireless wristwatch device to monitor patient gait. The device can transmit real-time data to caregivers or other healthcare providers through a smartphone, tablet or other mobile devices. The Bluetooth-powered device includes a panic button and is designed to deliver "continuous, real-time health and safety monitoring on an end-to-end FDA-cleared cloud-based medical data platform." Caregivers will have the ability to generate custom alerts based on a patient's wellness profile or individual care plan. This will give both caregivers and patients a higher level of independence. Cindy Crump is CEO and founder of AFrame Digital. In prepared remarks, she stated, "Our corporate mission is to support the health and safety of elderly adults as they age in place, as well as post-acute patients across care settings and patients at risk for hospitalization." She continued, "We advance this mission by delivering the most advanced real-time telemonitoring solutions in the market." References

New House Bill Would Create FDA Mobile Health Division

A new bill was introduced on the House floor by representative Mike Honda (D-CA). The new bill, dubbed the Healthcare Innovation & Marketplace Technologies Act, calls for the creation of a new FDA division to boost health information technologies and wireless health programs in the United States. If the bill is passed into law, the FDA will be called to develop support programs to spur development of HIPAA programs. In addition, the bill calls for the FDA to create prize-based innovator challenges to spur advances in wireless healthcare technology. The bill also includes a loan program to bolster the adoption of information technology systems at small clinics and rural healthcare facilities. In prepared remarks, Mike Honda said, "As we continue to improve our health care system, technology can and should play a prominent role in achieving better care for Americans." He continued, "Why have the principles of Silicon Valley, which I represent - competition, innovation, and entrepreneurship - not fully manifested themselves in the healthcare information technology space? This bill gets us closer to that space." The House bill also calls for the creation of an Office of Wireless Health (OWH). The OWH would be tasked with the job of creating a reasonable, predictable and consistent regulatory framework for the oversight of upcoming digital and wireless health technologies. References

How Osseointegration Is Improving Prosthesis Design

By developing prosthetic devices that rely on implanting electrodes directly in nerves and remaining muscle, Chalmers University researchers aim to provide amputees with greater control over prosthetic movements.

Researchers at Chalmers University of Technology (Gothenburg, Sweden) are developing a new method for controlling prostheses for amputees that relies on the power of osseointegration.

Since the 1960s, prostheses have been controlled by electrical impulses in the muscles. However, the technology for controlling these prostheses has not evolved greatly since then. For example, while advanced electric hand prostheses are available, their functionality is limited because they are difficult to control. "All movements must by preprogrammed," remarks Max Ortiz Catalan, industrial doctoral student at Chalmers University. "It's like having a Ferrari without a steering wheel. Therefore, we have developed a new bidirectional interface with the human body, together with a natural and intuitive control system."

Uncomfortable and unpopular, current standard socket prostheses are attached to the body using a socket tightly fitted on the amputated stump. In order to pick up electrical signals to control the prostheses, electrodes are placed over the skin. However, when the skin moves, the signals change, since the electrodes move to a different position. In addition, the signals are also affected when amputees sweat, since the resistance on the interface changes.
In contrast, the new technology helps amputees to control artificial limbs much as they control their own biological hands or arms--by using their own nerves and remaining muscles. "Osseointegration is vital to our success," Catalan says. "We are now using the technology to gain permanent access to the electrodes that we will attach directly to nerves and muscles. In this project, the researchers are planning to implant the electrodes directly on the nerves and remaining muscles instead. Since the electrodes are closer to the source and the body acts as protection, the bioelectric signals become much more stable.
Osseointegration is used to enable the signals inside the body to reach the prosthesis. The electrical impulses from the nerves in the arm stump are captured by a neural interface, which sends them to the prostheses through the titanium implant. These are then decoded by sophisticated algorithms that allow the patient to control the prosthesis using thoughts.
In existing prostheses, amputees use only visual or auditory feedback. As a result, amputees must look at or hear the motors in the prosthesis in order to estimate the grip force applied to a cup if they wish to move it around. Using the new method, patients receive feedback as the electrodes stimulate the neural pathways to the patient's brain, just as the physiological system does.

The Impact of Comparative Effectiveness Research on Spine Care Device Companies

Recent trends in healthcare expenditures related to spine care show increasing costs and significant geographical variations in treatment patterns. These data, along with a lack of consistent success for spinal surgeries, has led to increased scrutiny of the spine care industry by payers. Expenditures associated with spine problems totaled $86 billion in 2005, an increase of 65% since 1997. What some consider “overtreatment” of chronic back pain has occurred through the use of imaging, opioid analgesics, spinal injections, and surgery.1 Some studies on complex procedures and devices have even found that lumbar fusion surgery for discogenic axial low back pain appears to offer only limited relative benefits over cognitive behavioral therapy and intensive rehabilitation, and that as few as 50% of fusion patients are likely to have high-quality outcomes.2   

To promote lower costs and better outcomes, the American Recovery and Reinvestment Act of 2009 (ARRA), allocated $1.1 billion to Comparative Effectiveness Research (CER). The Institute of Medicine (IOM) defines CER as a comparison of the benefits and harms of alternative methods to prevent, diagnose, treat, and monitor a clinical condition or to improve the delivery of care.3 Ideally, policymakers would like to reduce costs without impacting the quality (or the perceived quality) of healthcare, and comparative effectiveness research is seen as one way to get there, since CER takes both clinical effectiveness and cost into consideration. By replacing ineffective treatments and standards of clinical care with effective ones, or by replacing more expensive treatments and standards with equally effective, but less expensive ones, the cost of care can be brought down, in the words of the Congressional Budget Office (CBO) “without adverse health consequences.”4 

The CBO has consistently pointed to evidence in support of the idea that there are massive savings to be had by changing patterns of clinical practice.5 The evidence for this comes from several sources. First, other countries have equivalent or better outcomes with much lower costs.6 Second, an analysis of Medicare spending within the U.S. showed large variations across regions in cost per patient that were not associated with increased illness, higher payment rates, or better outcomes.7 By some estimates, total Medicare costs could be reduced by 30% if the entire country adopted the practice patterns of the most efficient regions. It has also been estimated that between 30% and 65% of all surgeries that are performed in high use regions are either clinically inappropriate or of “equivocal” value.8 

For these reasons, CER findings, once established, are likely to find their way into guidelines and restrictions by payers on eligibility for procedures. Consequently, companies that make medical devices for spine care must begin to better demonstrate the value of their products for the treatment of spinal conditions, or run the risk of losing market share and even access for lack of an economic and clinical value proposition.

Comparative Effectiveness Research

It is worth noting the relationship between CER and Evidence Based Medicine (EBM). CER is similar to EBM in that both, in principle, are about providing high quality evidence. EBM focuses on use of current best evidence in making decisions about the care of individual patients. In contrast, CER is broader, comparing the benefits and harms of alternative methods to prevent, diagnose, treat, and monitor a clinical condition and is used for individual and population level decisions.  

As part of the CER funding, the IOM was commissioned to create a report outlining priority areas for CER studies. According to the IOM, “there frequently are no studies that directly compare the different available alternatives or that have examined their impacts in populations of the same age, sex, and ethnicity or with the same comorbidities as the patient.  Comparative effectiveness research (CER) is designed to fill this knowledge gap.”9  

The IOM report went on to identify a number of spine care issues among its top 100 priority areas for CER, after obtaining input from professional organizations and the public, as required by ARRA. The topics were divided into quartiles, with the first quartile considered the most important. Some of the spine care related issues that were among those prioritized included the following:

  • Establish a prospective registry to compare the effectiveness of treatment strategies for low back pain without neurological deficit or spinal deformity (First Quartile).
  • Compare the effectiveness of treatment strategies (e.g. artificial cervical discs, spinal fusion, pharmacologic treatment with physical therapy) for cervical disc and neck pain (Second Quartile).
  • Compare the long-term effectiveness of weight-bearing exercise and bisphosphonates in preventing hip and vertebral fractures in older women with osteopenia and/or osteoporosis (Second Quartile).
  • Establish a prospective registry to compare the effectiveness of surgical and non-surgical strategies for treating cervical spondylotic myelopathy (CSM) in patients with different characteristics to delineate predictors of improved outcomes (Third Quartile).
  • Compare the effectiveness of traditional and newer imaging modalities (e.g. routine imaging, magnetic resonance imaging [MRI], computed tomography [CT], positron emission tomography [PET] when ordered for neurological and orthopedic indications by primary care practitioners, emergency department physicians and specialists (Third Quartile).
  • Compare the effectiveness (e.g. pain relief, functional outcomes) of different surgical strategies for symptomatic cervical disc herniation in patients for whom appropriate nonsurgical care has failed (Fourth Quartile).

CER priorities targeted orthopedics, particularly spine, because it's so costly, and because of concerns about patient outcomes.  Spine care device manufacturers will be increasingly challenged to demonstrate differential effectiveness – in terms of clinical outcomes and cost – of their devices.  Without doing so, they stand to face significant restrictions in reimbursement by CMS and payers.   Device manufacturers need to look to new methods of demonstrating value for payers and patients.  They will need to prove benefit over existing products, and usefulness in treating spinal conditions.

Are device companies being overly aggressive in promoting their products?

CER is about the improvement of treatment protocols and comparing available products to the competition to determine which ones work best and at the lowest cost. Device manufacturers can’t simply market their products without having clear evidence that they will be effective (based on cost and outcomes) for a particular course of treatment. CER focuses on spine care because of its high cost and the frequent failure of spinal surgery to make a clinical difference to patients. As such, CER will put pressure on manufacturers to change their approach to integrating products within the new healthcare delivery model. It will be essential that they ensure appropriate use of their devices, rather than simply pushing new technology.  

Specifically, the healthcare delivery industry can expect to feel significant pressure from CER in two particular areas. The first of these will be in the development of predictive care paths. These will identify what treatment protocols work best, including the value of certain devices and procedures. Once these specific treatment patterns become the standard, they will

a) be adopted by most private insurers.

b) be adopted by physicians themselves as the default standard of treatment.  

These care paths are certain to impact the projected priority areas earliest and most strongly, which has implications for spine care.  

The second consequence of CER for the delivery industry will be changing quality metrics. Traditional methods (measuring mortality and morbidity) will be replaced by a combination of process metrics (compliance with guidelines) and outcome metrics that integrate quality of life into traditional measures. This will take place as part of the shift from a focus on clinical effectiveness to a focus on cost effectiveness, because cost effectiveness is nearly universally defined to include quality of life (e.g. the QALY, or quality-adjusted life year).

In addition, just demonstrating that a product works and is cost-effective may not be enough.  This is why manufacturers need to additionally focus on showing the value of a product within the context of care paths, and as such, may need to help doctors improve their diagnostic specificity. It’s about making sure a patient receives the right treatment with the right product at the right time… to achieve the right outcome. A 50% failure rate is a damning statistic. If your device is part of a surgical treatment that can’t claim a better success rate than a coin flip, your product will not be identified as a viable option.

Changing perceptions of value suggest that manufacturers will need to provide evidence on the appropriate use of their devices, and outcomes data that demonstrates effectiveness – not just data demonstrating product capabilities.  If manufacturers just stand by and leave CER to the researchers, HHS will eventually restrict use of devices based on its research, and manufacturers will have lost their opportunity for meaningful input, at significant cost. Additionally, in the context of growing healthcare consolidation, manufacturers will need to prove their product value to purchasing organizations or rely purely on price concessions to retain access in the face of vendor consolidation. The choice for manufacturers it to take the initiative now, or risk losing market position and market access later. 

The Next Steps

Philosophically, NAI advocates taking steps to try and shape the future, especially the regulatory environment. Consequently, we recommend that manufacturers partner with providers and fund research to gather acute and post-acute care data as a basis for improving diagnostic accuracy. Use of registries combined with longitudinal follow ups can yield the kind of data that will make this possible. This includes capturing information about products, techniques, comorbidities, etc. A good model for this can be found in cardiology. The registry maintained by the Society of Thoracic Surgeons captures critical acute care data. If this could be combined with longitudinal follow-up data it could provide a wealth of meaningful information about implant functionality and much more.

There are also business development opportunities in integrating services with products to enhance both (like physical therapy). Medical device companies could also partner with hospitals/systems/clinics that do surgeries. The important thing is to give providers a compelling argument demonstrating outcomes in terms of safety, efficacy, and cost to improve reimbursement.

Providers have an interest in being able to demonstrate the value of their own clinical work and so should be willing partners in the enterprise. As a bonus, it may open doors to opportunities for a service wrap approach for manufacturers that could enhance the brand and create new revenue streams.

Spine care will remain a priority of CER given the current variation in outcomes and treatment patterns, and that current evidence indicates higher surgery rates (with higher costs) do not necessarily demonstrate better outcomes, and sometimes demonstrate worse outcomes.  CER establishes the reason for using a product or treatment protocol.  Registries or longitudinal research is the action that manufacturers/providers can take to establish value.  The purpose of all this is to sharpen diagnostic accuracy and defend against more restrictive action by CMS and private payers. Such investments now can be the key to your future bottom line.  


  1. Manchikanti L, et al. "Facts, fallacies, and politics of comparative effectiveness research: Part I.," Pain Physician Journal, 2010.
  2. Carragee EJ. "The role of surgery in low back pain," Current Orthopaedics 21, no. 1 (2007): 9–16.
  3. IOM (Institute of Medicine). "Initial National Priorities for Comparative Effectiveness Research," (The National Academies Press, Washington, DC: 2009): 13.
  4. Congressional Budget Office, Research on the Comparative Effectiveness of Medical Treatments. December, 2007.
  5. Congressional Budget Office, World Health Organization The World Health Report 2000. June, 2000.
  6. Voelker R. "US Health Care System Earns Poor Marks," Journal of the American Medical Association 300; no. 24 (December 24, 2008): 2843.
  7. Dartmouth Atlas Project, Dartmouth Atlas of Health Care, cited in Research on the Comparative Effectiveness of Medical Treatments.
  8. Chassin MR, Kosecoff J, Park RE, et al. Does Inappropriate Use Explain Geographic Variation in the Use of Health Care Services? A Study of Three Procedures. JAMA. November 13, 1987. vol. 258; no. 18: pp. 2533-2537.
  9. IOM (Institute of Medicine). Initial National Priorities for Comparative Effectiveness Research. Washington, DC: The National Academies Press. 2009. p. 1.


Rita E. Numerof, Ph.D. is President of Numerof & Associates, Inc. (NAI). NAI is a strategic management consulting firm focused on organizations in dynamic, rapidly changing industries. We bring a unique cross-disciplinary approach to a broad range of engagements designed to sharpen strategic focus, increase revenues, reduce costs, and enhance customer value. For more information, contact NAI via email at [email protected] or by phone 314-997-1587. 


Conscious Awareness is Highly Overrated: Adventures in Medical Device Usability

Read all Adventures in Medical Device Usability by
Steve Wilcox

 I have an article coming out soon in the ACM journal, Interactions (Jan./Feb., 2013 issue), titled "The Problem with Transparency Is it’s not Conspicuous Enough." I thought I might summarize what I say there as it relates to the usability of medical devices. What I focus on is that the usability of a tool is closely associated with its transparency. That is, when a tool is really easy to use, it, in effect, disappears. The user focuses on the task, not the tool. A usable scalpel is one that allows the surgeon to focus on transecting tissue, not on the scalpel itself—that allows the surgeon, so to speak, to see through the scalpel to the tissue effect. 

Thus, awareness of a tool is usually a bad, not a good thing, which raises a number of interesting design challenges. The obvious implication is that a key job of the device designer is to design things so that they will disappear. But what does this mean? What does it mean to design for transparency? This isn’t so simple. I don’t think that industrial designers and design engineers take courses in making things disappear (although, maybe they should). However, it’s even more complicated than that, because a good device that’s transparent in use should be anything but transparent at other times. 

Take the example of an MRI system. In use, the system should disappear, in the sense that the tech who uses it should be thinking about getting a good image, not about how the system is operated. But, when the system is presented at a trade show, it should be anything but transparent. It should stand out among competitive units as particularly functional, elegant, safe, etc. It should be conspicuous as a thing of quality, even of beauty. Likewise, an MRI system should be anything but transparent as an object in the room; we don’t want people accidentally running into it.

It follows that one of the reasons device design is so hard is that the task of the designer (or, more typically, the largish, interdisciplinary group known as the design team) is to create things that disappear and reappear—disappear when they’re supposed to be transparent and reappear when they’re supposed to visible. A great device jumps out at the intended customer and demands that it be acquired, then promptly disappears when in use, then reappears again when not noticing it will compromise safety. It provides transparent access to things beyond it, but it is also conspicuous as an example of the latest technology, as a device that’s safe, as something that will last for many years, and so on.

It follows (as I said about product design, in general, in the Interactions article) that great device design involves the mastery of a dynamic transparency, or, alternatively, that you can’t be a great device designer unless you can control transparency with assurance.

What I’m claiming, in other words, is that the mastery of dynamic transparency is a central skill of the device designer. The problem, though, is that the mastering of dynamic transparency is itself transparent—it’s a crucial, but largely tacit skill, not one, as I mentioned, that is particularly taught to or particularly focused on by the designers and engineers who design medical devices.

Perhaps this should change. In other words, perhaps we need to make transparency less transparent. It seems to me that we ought to make transparent use an explicit design goal. Although, I admit that I have more questions than answers about how to do this, here are some initial thoughts about the implications of this line of thought:

We ought to be able to measure transparency.

One way to think about the issue is to imagine two devices that generate similar user performances, one that requires concentration on the device and one that doesn’t. It may be that, when using only the devices themselves, performance is equivalent. However, performance on other tasks (that the user would also have to perform under real-world circumstances) would be selectively undermined by the “cognitive load” associated with the less transparent device. If this reasoning is correct, then traditional measures of cognitive load, such as performance on a simultaneous additional task, should provide a measure of transparency. In other words, perhaps we can think of transparency as simply the inverse of high cognitive load. That probably is part of it.

The practical implication is that it may be useful to add tasks that measure cognitive load to our usability testing.

Because a transparent device is one that is used unconsciously (rather than consciously), interviews may not be the best tool for understanding what constitutes a usable device.

I would argue that we already know this. That’s why usability testing is largely behavioral rather than interview-based. This notion of transparency, though, reinforces my skepticism about too much reliance on what people say rather than what they do when it comes to usability (let alone safety). Stating the problem, though, as designing a device to be used unconsciously, helps to indicate the relative difficulty that the device designer faces. 

Transparency increases as a device user goes through the learning curve.

Except in rare cases, even a really usable device isn’t transparent in the beginning, but becomes so as the user goes through a learning curve. Thus, transparency is dynamic in the sense that it changes with experience. Perhaps we should use measures of transparency as criteria for the success of training.

The notion of transparency may be useful in understanding designing for people with disabilities.

Understanding how to design for people with a variety of disabilities is increasingly important as more devices move out of the clinical environment and into the home and as the population of healthcare professionals trends toward an older demographic (along with the rest of the population). One thing that’s interesting is that transparency varies depending on one’s abilities. A device that’s hard to hold for the person who struggles to achieve an affirmative grip will be far from transparent when that person picks it up. But it may be completely transparent for those who can grasp and hold it with ease. Likewise, a display screen that’s transparent for the person with good vision may not be for the person with a visual deficit. 

A logical design goal for a device would be to increase the percentage of the population for which the device remains transparent, as opposed to requiring special concentration and focus.

Well, as I said, I don’t claim to have a lot of answers regarding what this notion of transparency means. I’d like to suggest, though, that thinking about how a good tool becomes transparent to the user can provide insight into how we can design good medical devices.


Stephen B. Wilcox, is a principal and the founder of Design Science (Philadelphia), a 25-person firm that specializes in optimizing the human interface of products—particularly medical devices. Wilcox is a member of the Industrial Designers Society of America’s (IDSA) Academy of Fellows. He has served as a vice president and member of the IDSA Board of Directors, and for several years was chair of the IDSA Human Factors Professional Interest Section. He also serves on the human engineering committee of the Association for the Advancement of Medical Instrumentation (AAMI), which has produced the HE 74 and HE 75 Human Factors standards for medical devices.

Hybrid Printer Enables Fabrication of Implantable Cartilage

A new hybrid printer developed by researchers at the Wake Forest Institute for Regenerative Medicine (WFIRM; Winston-Salem, NC) simplifies the production of implantable cartilage, according to an article published by the Institute of Physics (London). The system could eventually be used to fabricate cartilage for use in such applications as joint reconstruction.

Combining two low-cost fabrication techniques, ink-jet printing and electrospinning, the printer has enabled the researchers to build structures made from both natural and synthetic materials. While the synthetic materials impart strength to the construct, the natural gel materials promote cell growth.

Employing an electrical current to generate very fine fibers from a polymer solution, the electrospinning machine allows users to control the composition of the polymers, thereby producing porous structures that encourage cells to integrate into surrounding tissue. "This is a proof of concept study and illustrates that a combination of materials and fabrication methods generates durable implantable constructs," remarks James Yoo, WFIRM professor and an author of a study published in the journal Biofabrication. "Other methods of fabrication, such as robotic systems, are currently being developed to further improve the production of implantable tissue constructs."

In this study, flexible mats of electrospun synthetic polymer were combined, layer-by-layer, with a solution of cartilage cells from a rabbit ear that were deposited using a traditional ink-jet printer. A week after testing the strength of the mats, the researchers tested them to determine whether the cartilage cells were still alive. Then, to determine how the mats performed, the scientists inserted them into mice for two, four, and eight weeks. Following implantation for eight weeks, the constructs appeared to have developed the structures and properties that are typical of elastic cartilage.

Norgren RM1 Pressure Regulator for Medical Gases

A company that works in pneumatic motion and fluid control technologies have released a new pressure regulator targeted at medical device manufacturers that want to ensure products deliver air or medical gases accurately even at low pressures and low flows. The RM1 pressure regulator is designed in accordance with relevant international standards and is available with both high and low flow options for matching regulator performance with application requirements. The RM1 has a cartridge design to enable integration into acrylic, aluminum, brass, or stainless steel manifolds, depending on OEM design requirements. The company says that with performance comparable to much larger units, the reduced size and weight of the RM1 make it attractive for compact or portable systems.

Littleton, CO