Spinal stimulators repurposed to restore touch in lost limb
Imagine tying your shoes or taking a sip of coffee or cracking an egg but without any feeling in your hand. That's life for users of even the most advanced prosthetic arms. Although it's possible to simulate touch by stimulating the remaining nerves in the stump after an amputation, such a surgery is highly complex and individualized. But according to a new study from the University of Pittsburgh's Rehab Neural Engineering Labs, spinal cord stimulators commonly used to relieve chronic pain could provide a straightforward and universal method for adding sensory feedback to a prosthetic arm. For this study, published July 21, 2020, in eLife, four amputees received spinal stimulators, which, when turned on, create the illusion of sensations in the missing arm. The strings of implanted spinal electrodes run along the spinal cord, where they sit slightly to one side, atop the same nerve roots that would normally transmit sensations from the arm. Since it's a spinal cord implant, even a person with a shoulder-level amputation can use this device. The researchers sent electrical pulses through different spots in the implanted electrodes, one at a time, while participants used a tablet to report what they were feeling and where. All the participants experienced sensations somewhere on their missing arm or hand, and they indicated the extent of the area affected by drawing on a blank human form. Three participants reported feelings localized to a single finger or part of the palm. When asked to describe not just where but how the stimulation felt, all four participants reported feeling natural sensations, such as touch and pressure, though these feelings often were mixed with decidedly artificial sensations, such as tingling, buzzing or prickling. Although some degree of electrode migration is inevitable in the first few days after the leads are implanted, the researchers found that the electrodes, and the sensations they generated, mostly stayed put across the month-long duration of the experiment. That's important for the ultimate goal of creating a prosthetic arm that provides sensory feedback to the user.
Genetic testing could improve screening for osteoporosis
An international team of scientists has developed a novel genetic measure that could dramatically improve how doctors assess the risk of sustaining a fracture due to osteoporosis or fragility A full genome profile can be generated for approximately £35-£40 per patient, a cost that is comparable to or lower than the cost of an X-ray to measure bone mineral density. By generating a single genomic profile, researchers can also identify multiple risk factors for diseases like cancer, cardiovascular disease and osteoporosis. Embedding genetic testing into routine clinical practice could improve the efficiency and cut costs of screening for common diseases such as osteoporosis, according to new research. An international team of scientists, including researchers from the University of Sheffield, has developed a novel genetic measure that could dramatically improve how doctors assess the risk of sustaining a fracture due to osteoporosis or fragility. The new study published in the journal PLOS Medicine demonstrates how more extensive applications of genomic screening might be used to improve the delivery of health care. Researchers tested whether a risk score gathered from information across a panel of over 20,000 genes could be used as a substitute for a measure of bone strength called heel quantitative ultrasound speed of sound (SOS).The risk score, termed gSOS, was developed using the UK Biobank which provided SOS measurements for 341,449 individuals. The international research team then applied gSOS alongside the Sheffield-developed FRAX tool, which evaluates the fracture risk of patients based on individual models that integrate clinical risk factors as well as bone mineral density, to determine its impact on the need for actual measurements of bone strength which are usually carried out in hospital by X-ray. The study estimated that the application of gSOS could reduce the number of FRAX tests and bone mineral density-based FRAX tests by 37% and 41%, respectively, while maintaining a high sensitivity and specificity to identify individuals who should be recommended for intervention. Lead researcher, Brent Richards, a geneticist at the Lady Davis Institute's Centre for Clinical Epidemiology and Professor of Medicine, Human Genetics, and Epidemiology and Biostatistics at McGill University, said: "By generating a single genomic profile, we can identify multiple risk factors for diseases like cancer, cardiovascular disease and osteoporosis.
Study shows genetic markers are useful in predicting osteoporotic fracture risk
A new study shows that genetic pre-screening could reduce the number of screening tests needed to identify individuals at risk for osteoporotic fractures. Douglas Kiel, director of the Musculoskeletal Research Center in the Hinda and Arthur Marcus Institute for Aging Research at Hebrew Seniorlife, is an author on the report published in PLOS Medicine. Dual-energy X-ray absorptiometry (DXA), which measures bone mineral density (BMD), has been considered the clinical standard for determining fracture risk, along with the Fracture Risk Assessment Tool (FRAX). A FRAX assessment considers factors such as age, gender, weight, alcohol use, smoking history, and fracture history. Screening programs are generally designed to identify those whose risk is great enough to require intervention. However, assessment takes time and DXA accessibility has declined. Usually only a small proportion of individuals who undergo screening is found to be at high risk, indicating that much of the screening expenditure is spent on individuals who will not qualify for treatment. The potential exists to improve the efficiency of osteoporosis screening programs using genetic markers to assess fracture risk. The purpose of this study was to understand if genetic pre-screening could reduce the number of screening tests needed to identify individuals at risk of osteoporotic fractures. It used genetic data from more than 300,000 participants from the UK Biobank to calculate the genetically predicted bone ultrasound measure. This was then compared with the commonly used FRAX score and standard BMD measured by DXA as to its ability to predict the risk for fracture. By building a polygenic risk score and validating its utility in fracture risk screening in five separate cohorts totaling more than 10,000 individuals, study researchers determined that genomics-enabled fracture risk screening could reduce the proportion of people who require BMD-based testing by 41%, while maintaining a high ability to correctly determine appropriate treatment for those at risk. While these findings are not meant to be prescriptive, they indicate the possible utility of polygenic risk scores in screening programs that are dependent on heritable risk factors.