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New Tech May Make Prosthetic Hands Easier For Patients To Use

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Researchers have developed new technology for decoding neuromuscular signals to control powered, prosthetic wrists and hands. The work relies on computer models that closely mimic the behavior of the natural structures in the forearm, wrist and hand. The technology could also be used to develop new computer interface devices for applications such as gaming and computer-aided design (CAD).

The technology has worked well in early testing but has not yet entered clinical trials — making it years away from commercial availability. The work was led by researchers in the joint biomedical engineering program at North Carolina State University and the University of North Carolina at Chapel Hill.

Current state-of-the-art prosthetics rely on machine learning to create a “pattern recognition” approach to prosthesis control. This approach requires users to “teach” the device to recognize specific patterns of muscle activity and translate them into commands — such as opening or closing a prosthetic hand.

“Pattern recognition control requires patients to go through a lengthy process of training their prosthesis,” says He (Helen) Huang, a professor in the joint biomedical engineering program at North Carolina State University and the University of North Carolina at Chapel Hill. “This process can be both tedious and time-consuming.

“We wanted to focus on what we already know about the human body,” says Huang, who is senior author of a paper on the work. “This is not only more intuitive for users, it is also more reliable and practical.

“That’s because every time you change your posture, your neuromuscular signals for generating the same hand/wrist motion change. So relying solely on machine learning means teaching the device to do the same thing multiple times; once for each different posture, once for when you are sweaty versus when you are not, and so on. Our approach bypasses most of that.”

Instead, the researchers developed a user-generic, musculoskeletal model. The researchers placed electromyography sensors on the forearms of six able-bodied volunteers, tracking exactly which neuromuscular signals were sent when they performed various actions with their wrists and hands. This data was then used to create the generic model, which translated those neuromuscular signals into commands that manipulate a powered prosthetic.

“When someone loses a hand, their brain is networked as if the hand is still there,” Huang says. “So, if someone wants to pick up a glass of water, the brain still sends those signals to the forearm. We use sensors to pick up those signals and then convey that data to a computer, where it is fed into a virtual musculoskeletal model. The model takes the place of the muscles, joints and bones, calculating the movements that would take place if the hand and wrist were still whole. It then conveys that data to the prosthetic wrist and hand, which perform the relevant movements in a coordinated way and in real time — more closely resembling fluid, natural motion.

“By incorporating our knowledge of the biological processes behind generating movement, we were able to produce a novel neural interface for prosthetics that is generic to multiple users, including an amputee in this study, and is reliable across different arm postures,” Huang says.

And the researchers think the potential applications are not limited to prosthetic devices.

“This could be used to develop computer-interface devices for able-bodied people as well,” Huang says. “Such as devices for gameplay or for manipulating objects in CAD programs.”

In preliminary testing, both able-bodied and amputee volunteers were able to use the model-controlled interface to perform all of the required hand and wrist motions — despite having very little training.

“We’re currently seeking volunteers who have transradial amputations to help us with further testing of the model to perform activities of daily living,” Huang says. “We want to get additional feedback from users before moving ahead with clinical trials.

“To be clear, we are still years away from having this become commercially available for clinical use,” Huang stresses. “And it is difficult to predict potential cost, since our work is focused on the software, and the bulk of cost for amputees would be in the hardware that actually runs the program. However, the model is compatible with available prosthetic devices.”

The researchers are also exploring the idea of incorporating machine learning into the generic musculoskeletal model.

“Our model makes prosthetic use more intuitive and reliable, but machine learning could allow users to gain more nuanced control by allowing the program to learn each person’s daily needs and preferences and better adapt to a specific user in the long term,” Huang says.

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Report Reveals Link Between Air Pollution And Increased Risk For Miscarriage

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Air quality has been associated with numerous adverse health outcomes from asthma to pre-term birth. Researchers at University of Utah Health found women living along the Wasatch Front — the most populous region in the state of Utah — had a higher risk (16 percent) of miscarriage following short-term exposure to elevated air pollution. The results are available online on December 5 in the journal Fertility and Sterility.

“Not being from Salt Lake originally, I noticed a pattern in the relation to air quality and pregnancy loss,” said Matthew Fuller, M.D., assistant professor of Surgery at U of U Health and senior author on the paper.

“I knew this was an understudied question so we decided to dig deeper.”

Fuller joined University of Utah research analyst Claire Leiser on a retrospective study consisting of more than 1,300 women (54 percent Caucasian, 38 percent Hispanic, and other/missing 8 percent; average age 28 years). The women in the study sought help at the U of U emergency department following a miscarriage (up to 20-weeks gestation) between 2007 to 2015.

The team examined the risk of miscarriage during a three- or seven-day window following a spike in the concentration of three common air pollutants: small particulate matter (PM 2.5), nitrogen dioxide and ozone. The study excluded women who lived outside Utah.

“We are really only seeing the most severe cases during a small window of time,” said Leiser, first author on the paper.

“These results are not the whole picture.”

Leiser notes the results suggest there could be an increased risk for an individual. Their research only captured women who sought help at an emergency department at one hospital in the region. It does not account for women who may have sought outpatient care through their obstetric or primary care providers.

The team found a slight increased risk in miscarriage for women exposed to elevated levels of nitrogen dioxide (16 percent for 10 ppb increase during the seven-day window). Although small particulate matter does track with nitrogen dioxide, these results did not significantly associate with an increased risk of miscarriage.

“While we live in a pretty unique geographic area, the problems we face when it comes to air pollution are not unique,” said Fuller.

“As the planet warms and population booms, air pollution is going to become a bigger problem not only in the developing world but across the United States.”

The Wasatch Front experiences short-periods of poor air quality, primarily during the winter months, when inversions trap pollutants close to the ground (for the 7-day window: PM2.5 min = 0.3 μg/m3; PM2.5 max = 73.0 μg/m3; O3 min = 4 ppb; O3 max= 80 ppb; NO2min = 0.5 ppb; NO2 max = 65 ppb). The researchers tracked air quality by zip code, establishing six designated air basins within the Wasatch Front. They compared air quality in each basin to their patients’ outcomes.

The team conducted a case cross-over study that estimated a woman’s risk of miscarriage multiple times in a month where air pollution exposure varied. This approach removed other risk factors, like maternal age, from the study. The scientists were unable to ascertain the age of the fetus at the time of the miscarriage and were unable pinpoint a critical period when the fetus may be most vulnerable to pollutants.

“The results of this study are upsetting, and we need to work together as a society to find constructive solutions,” Fuller said.

Fuller recommends women speak with their doctor about any health concerns. Women can manage the risk by using a N95 particulate respirator face mask to filter out pollutants or avoid outdoor physical activity on poor air quality days. Women can also use filters to lower indoor pollution and, if possible, time conception to avoid seasonal episodes of poor air quality.

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Alcohol Intake May Be Key to Long-term Weight Loss for People with Diabetes

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Research shows that losing weight can help prevent or delay the onset of diabetes. While best practice for weight loss often includes decreasing or eliminating calories from alcohol, few studies examine whether people who undergo weight loss treatment report changes in alcohol intake and whether alcohol influences their weight loss.

A new study from the University of Pennsylvania School of Nursing (Penn Nursing) suggests that alcohol consumption may attenuate long-term weight loss in adults with Type 2 diabetes.

In the study, close to 5,000 people who were overweight and had diabetes were followed for four years. One group participated in Intensive Lifestyle Intervention (ILI) and the other in a control group consisting of diabetes support and education. Data showed that participants in the ILI group who abstained from alcohol consumption over the four-year period lost more weight than those who drank any amount during the intervention. Results from the study also showed that heavy drinkers in the ILI group were less likely to have clinically significant weight loss over the four years.

“This study indicates that while alcohol consumption is not associated with short‐term weight loss during a lifestyle intervention, it is associated with worse long‐term weight loss in participants with overweight or obesity and Type 2 diabetes,” says lead investigator Ariana M. Chao, PhD, CRNP, Assistant Professor of Nursing in the Department of Biobehavioral Health Sciences.

“Patients with Type 2 diabetes who are trying to lose weight should be encouraged to limit alcohol consumption.”

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Hang In There. As Couples Age, Humor Replaces Bickering

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Honeymoon long over? Hang in there. A new UC Berkeley study shows those prickly disagreements that can mark the early and middle years of marriage mellow with age as conflicts give way to humor and acceptance.

Researchers analyzed videotaped conversations between 87 middle-aged and older husbands and wives who had been married for 15 to 35 years, and tracked their emotional interactions over the course of 13 years. They found that as couples aged, they showed more humor and tenderness towards one another.

Overall, the findings, just published in the journal Emotion, showed an increase in such positive behaviors as humor and affection and a decrease in negative behaviors such as defensiveness and criticism. The results challenge long-held theories that emotions flatten or deteriorate in old age and point instead to an emotionally positive trajectory for long-term married couples.

“Our findings shed light on one of the great paradoxes of late life,” said study senior author Robert Levenson, a UC Berkeley psychology professor.

“Despite experiencing the loss of friends and family, older people in stable marriages are relatively happy and experience low rates of depression and anxiety. Marriage has been good for their mental health.”

Consistent with previous findings from Levenson’s Berkeley Psychophysiology Laboratory, the longitudinal study found that wives were more emotionally expressive than their husbands, and as they grew older they tended toward more domineering behavior and less affection. But generally, across all the study’s age and gender cohorts, negative behaviors decreased with age.

“Given the links between positive emotion and health, these findings underscore the importance of intimate relationships as people age, and the potential health benefits associated with marriage,” said co-lead author Alice Verstaen, who conducted the study as a Ph.D. student at UC Berkeley and is currently a postdoctoral fellow at the VA Puget Sound Health Care System.

The results are the latest to emerge from a 25-year UC Berkeley study headed by Levenson of more than 150 long-term marriages. The participants, now mostly in their 70s, 80s and 90s, are heterosexual couples from the San Francisco Bay Area whose relationships Levenson and fellow researchers began tracking in 1989.

In their investigation of marital relationships, researchers viewed 15-minute interactions between spouses in a laboratory setting as they discussed shared experiences and areas of conflict. They tracked the emotional changes every few years.

The spouses’ listening and speaking behaviors were coded and rated according to their facial expressions, body language, verbal content and tone of voice. Emotions were coded into the categories of anger, contempt, disgust, domineering behavior, defensiveness, fear, tension, sadness, whining, interest, affection, humor, enthusiasm and validation.

Researchers found that both middle-aged and older couples, regardless of their satisfaction with their relationship, experienced increases in overall positive emotional behaviors with age, while experiencing a decrease in overall negative emotional behaviors.

“These results provide behavioral evidence that is consistent with research suggesting that, as we age, we become more focused on the positives in our lives,” Verstaen said.

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