Month: July 2018

Wearable device designed to measure cortisol in sweat

Photo by Brodie Vissers

Scientists are sweating over how to measure perspiration. That’s because sweat provides a lot of information about a person’s health status, since it contains important electrolytes, proteins, hormones and other factors.

Now, Stanford researchers have developed a wearable device to measure how much cortisol people produce in their sweat.

Cortisol is a hormone critical for many processes in the body, including blood pressure, metabolism, inflammation, memory formation and emotional stress. Too much cortisol over a prolonged period of time can lead to chronic diseases, such as Cushing syndrome.

“We are particularly interested in sweat sensing, because it offers noninvasive and continuous monitoring of various biomarkers for a range of physiological conditions,” said Onur Parlak, PhD, a Stanford postdoctoral research fellow in materials science and engineering, in a recent news release. “This offers a novel approach for the early detection of various diseases and evaluation of sports performance.”

Currently, cortisol levels are usually measured with a blood test that takes several days to analyze in the lab. So Stanford material scientists developed a wearable sensor — a stretchy patch placed on the skin. After the patch soaks up sweat, the user attaches it to a device for analysis and gets the cortisol level measurements in seconds.

As recently reported in Science Advances, the new wearable sensor is composed of four layers of materials. The bottom layer next to the skin passively wicks in sweat through an array of channels, and then the sweat collects in the reservoir layer. Sitting on top of the reservoir is the critical component, a specialized membrane that specifically binds to cortisol. Charged ions in the sweat, like sodium or potassium, pass through the membrane unless the bound cortisol blocks them — and those charged ions are detected by the analysis device, rather than directly measuring the cortisol. Finally, the top waterproof layer protects the sensor from contamination.

The Stanford researchers did a series of validation tests in the lab, and then they strapped the device onto the forearms of two volunteers after they went for a 20-minute outdoor run. Their device’s lab and real-world results were comparable to the corresponding cortisol measurements made with a standard analytic biochemistry assay.

Before this prototype becomes available, however, more research is needed. The research team plans to integrate the wearable patch with the analysis device, while also making it more robust when saturated with sweat so it’s reusable. They also hope to generalize the design to measure several biomarkers at once, not just cortisol.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Inaccurate direct-to-consumer raw genetic data can harm patients, new research suggests

Image by Clker-Free-Vector-Images

Whether or not you’ve ever had genetic testing, you probably know someone that has. Millions of people each year have their DNA analyzed by companies like 23andMe and Ancestry.com, seeking out personalized information about their heritage, health and other traits.

“The general public is excited about genetics because it can tell us a lot about our past ancestry and, if the right technology is used, about our future­­ ­— such as the likelihood of developing certain health problems,” said Tia Moscarello, a genetic counselor with Stanford’s Center for Inherited Cardiovascular Disease. “These tests are popular for good reason: many people want to be proactive about their health without spending a lot of money or making a trip to the doctor’s office to do it.”

Typically, these direct-to-consumer (DTC) genetic tests are less expensive than more comprehensive, clinical-grade genetic tests obtained through a health care provider.

However, the Food and Drug Administration limits what these companies can say about a consumer’s health. So many people download their raw genetic data obtained from the company, and then upload it to another company’s website for additional interpretation. But their raw data come with a disclaimer stating the information is not validated for accuracy nor intended for medical use.

“To our understanding, raw genetic data doesn’t go through quality control. We and the DTC labs know that raw data may not be accurate,” Moscarello said. For instance, a small study recently showed that 40 percent of genetic variants identified in direct-to-consumer raw data and sent for clinical confirmation were false positives — meaning that the genetic variants weren’t really present.

Moscarello has personally witnessed the impact of these false positives on patients and their families. In a recent commentary in Genetics in Medicine, she and her colleagues describe two cases of false positives seen at Stanford and two more seen at other institutions. These patients received raw data with genetic variants known to be associated with inherited heart conditions that would predispose them to sudden death, she said. Fortunately, a clinical lab determined that the results were incorrect.

Moscarello said she and her co-authors wrote the commentary to call attention to the potential harms of direct-to-consumer raw data interpretation, which extend beyond the potential for inaccurate results. She explained:

“Finding out that you or a family member are at risk for an inherited heart condition can be a very emotional, life-changing event. To go through that without an expert to talk to, or perhaps without support systems nearby, was challenging for our patients. They had to wait for an appointment with a genetic counselor who could explain the test and its limitations, and to provide support. That is usually provided prior to genetic testing, so patients can decide if they would like to proceed.”

The commentary also discussed the impact that DTC testing is having on the health care system.  For the four cases, this burden included the time and expense of four clinical-grade genetic tests, several echocardiograms and electrocardiograms for each patient, multiple visits with physician specialists, an MRI, and the implant and subsequent explant of an implantable cardioverter defibrillator, Moscarello said.

So what can be done?  The authors call for more research to determine the frequency and impact of people being affected by false positives in their raw genetic data interpretations. When a result with potential clinical significance is found, they recommend that it be sent for confirmation to a clinical-grade lab. This should occur before the consumer has to undergo costly clinical evaluations and tests, she said, concluding:

“It is clear that DTC genetic testing is here to stay, and for good reason. So it’s important to focus on maximizing the benefits of such large-scale, clinician-free testing, while minimizing the harms to consumers.

Collaboration between clinicians, consumers and the DTC genetic testing companies is a priority. I hope that DTC genetic testing companies will work with clinical genetics experts to create educational resources — so that consumers and non-specialist physicians know the data may be inaccurate, and what to do next if something is found.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Stanford data analyst’s childhood inspires his research: A Q&A

Photo, of Jonathan Altamarino and collaborators in front of an Asili clinic, by Valery Namuto

Data analysts are critical to medical research — particularly to epidemiology studies that look at the incidence, distribution and determinants of health conditions in specific populations. So I was happy to have the opportunity to speak with Jonathan Altamirano, a research data analyst in Stanford’s Global Child Health Program.

How did you get involved in global health research?

“Growing up, I spent summers with family in Nicaragua in a very poor, rural coastal village called Puerto Cabezas. We would often lose water around noon and power by sunset. Personally,  I was lucky. I had food on the table every night. But I saw kids who didn’t — and that was my biggest impetus for getting into global health. I also got dengue and malaria one summer, which got me interested in science and epidemiology. It’s a weird thing to say: a mosquito almost killed me, so I wanted to go into medicine.

I knew I wanted to help less fortunate populations, but I wasn’t sure how I’d fit into that landscape. As a biology undergraduate at Stanford, I then took an epidemiology class taught by Bonnie Maldonado, MD and I fell in love with it. It looked at how best to approach problems: If you have an intervention, is it effective or not? And how can you tell? That got me interested in statistics and ways to model diseases.

When I was getting my masters in biology at Stanford, I took another class with Dr. Maldonado just after she started her polio project in Mexico, which is investigating vaccine-derived poliovirus transmission. And I was hired as a research data analyst for the project.”

You’re now working on a project in the Democratic Republic of the Congo. What exactly are you studying?

“We’re acting as external evaluators for Asili, a poverty-reduction program launched by the American Refugee Committee and IDEO.org aimed at improving child survival and reducing poverty in South Kivu. They’re bringing clean water and small-format health clinics to help these communities recover from years of civil conflict. I’m working with a team including Rasika Behl, Clea Sarnquist and Bonnie Maldonado to collect and analyze on-site data to measure the impact of these interventions.

We’re looking at household demographics — such as what their house is made of , whether they have land and other indicators of wealth. We’re also collecting various health information on the children — such as the incidence of stunting, wasting, diarrhea, fever and cough. And we’re collecting data on the mothers, looking at women empowerment metrics and views on gender relations.

We collect this data in the field with tablets, which I program and setup. After we provide training, local data collectors go out into the community and survey the households. We collected all the baseline data in 2016 and 2017. We’re now collecting the same data after the interventions to evaluate the effectiveness of Asili’s clean water and health clinic programs. We’re also interested in characterizing this understudied population.”

Why did you recently travel to DRC? What was that like?

“In April, I went to South Kivu to help train Asili data collectors to take the end-line data. It was really great to get to know the American Refugee Committee team.

This was my first time in DRC, and I was struck by similarities with my family’s village in Nicaragua. The colors of the houses were the same and the roofs were made of the same kind of corrugated metal. I saw households with a lot of kids in the same space, and I was like ‘yeah, everyone had that in Nicaragua.’ Also, an older woman was running a small restaurant — consisting of plastic lawn chairs and a giant cooking pot. And I immediately pictured our neighbor lady in Nicaragua who made carne asada every night. Of course, the villages in DRC weren’t exactly the same, but they brought up childhood memories.”

What’s next for you?

“We hope to continue working with American Refugee Committee to evaluate Asili as they roll out the program in new parts of Bukavu over the next several years.

Our team is also completing a randomized clinical trial on a gender-based violence intervention, which was rolled out in schools in Kenyan informal settlements to reduce rates of sexual assault in adolescents. We also recently secured funding to collect pilot data on gender-based violence prevention in Fiji and other Pacific islands, in collaboration with the RISE program and Monash University.

However, I’m hoping to apply to medical school next year, once I have time to study for the MCATs.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Virtual reality helps train emergency physicians

Photo by sasint

Imagine you are an emergency medicine resident, trying to focus on your patient with abdominal pain — asking about his medical history and symptoms as you give him a physical — but you keep getting interrupted. A technician stops by to hand you another patient’s EKG. A staff member asks about an order for pain medication for a different patient. And then you are called to see a psychiatric patient who is agitated. You return ready to focus and then an attending physician breaks in to redirect your attention to a new patient with a high heart rate.

All told, you’re interrupted 12 times during the patient exam. How can you possibly maintain your train of thought? How can you build trust with the patient, when all these disruptions are stressing him out?

The above narrative was inspired by the script of a new training simulation, which was filmed at Stanford’s emergency department as a virtual reality video.

This is a typical scenario faced by emergency physicians, who are interrupted on average every six minutes. These interruptions increase the likelihood of errors, so it is critical for emergency doctors to practice how to multitask in this fast-paced, high-risk and disruptive environment.

The script was written by Henry Curtis, MD, a Stanford clinical instructor in emergency medicine, and Cameron Mozayan, MD, a Stanford emergency medicine resident.

“A problem with many current learning modalities is that they don’t engage modern participants in an active, immersive learning environment, so it’s difficult to sustain their attention,” Curtis said. “Virtual reality-based education presents an innovative solution to address this problem. Distractions are minimized as the learner excitedly engages in the VR world. The perception of the experience also triggers strong memories, which connect them to the educational content. So participants allot their full attention as they contemplate important medical decisions.”

Over 30 health care educators and providers at the 2018 International Health Humanities Consortium Conference at Stanford tried the training simulation recently. While viewing, the participants were asked to choose which interruptions were more important than the patient-physician consultation. The participants then viewed the video again with expert pro and con discussions — interactively testing to see if the others’ viewpoints swayed their opinions on the importance of the interruptions.

“Training is more powerful if the participants are seeing it in 360 virtual reality and they are being engaged in an interactive experience,” Curtis told me.

Participants said the VR training realistically conveyed what it was like to work in an emergency department. One health care worker declared, “This experience makes me feel like I’m in the emergency department. I feel like I’ve seen all of these things happen at work.” Another said, “Sometimes emergency medicine feels like a warzone.” A third participant added, “I was feeling so tense in there with all of the interruptions.”

The users also provided insights. For instance, one person was struck by how often technology caused the interruptions.

Curtis worked with Jason Lowe, MD, and Anne Merritt, MD, members of Stanford’s medical humanities team and with Stanford’s Education Technology team to create the first video. Now, they are analyzing the data from the conference, and are planning a series of VR training simulations.

For his next project, Curtis is also working with Aussama Nassar, MD, to film a trauma simulation with an agitated patient who deteriorates into neurogenic shock after a bicycle accident.

Curtis said he hopes the virtual reality series will enhance the quality of the lessons learned during the training simulations, in addition to extending their reach to a larger audience. He added:

“VR education can be transported globally to allow learners across the world to immerse themselves in the intricacies of innumerable clinical encounters, as well as receive structured debriefing in the virtual world by renowned experts from Stanford University and the like.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.