Pages
Stay In Touch
More
© 2011, 2012 Health Futures Digest
| The latest in bionic arms, connected in a roundabout way to the brain, is providing an unprecedented degree of freedom to its wearer. It has been discovered that the neural chip implants that interface such prosthetics with the brain eventually cause the brain itself to accept the prosthetic as an integral part of the body. Our understanding of such plasticity in the brain may be accelerated by technologies such as a “neural matrix CCD” developed at Berkeley National Labs. It is “the first step in creating combined biological and electronic chip implants that can provide neural networks of living, interconnected nerve cells for testing drugs and sensing toxins for homeland security — and, someday, restoring the use of limbs and eyesight and improved mental functions in patients.”
Brain-machine interfaces are not the only devices finding their way into our heads. Epileptic seizures may be preventable by an implanted brain cooler, soon to be tested in primates. Perhaps harder to get into our heads is the imminent actuality of face transplants. As far as we know, no-one has yet performed one, but patients are currently being screened prior to undergoing face transplants at the Cleveland Clinic. The concept of transcranial magnetic stimulation (TMS) is another far-out concept gaining traction. It has recently shown signs of success in rehabilitating stroke victims. Other therapeutics news:
|
|
| Bionic Arm
An electrician who lost both arms from an electric shock was the first of four amputees to have an arm replaced with a bionic arm at the Rehabilitation Institute of Chicago (RIC). Now he can pick up an egg without breaking it, sense hot and cold, feed himself, shave, put on his own socks and glasses, weed and mow his garden, open jars, paint his windows, and play ball with his grandchildren. Six motors in the arm allow him to move his elbow, shoulder, and wrist simultaneously — he can put on his hat in one fluid movement. The arm is connected to his brain via four nerves taken from his shoulder and transferred on to his chest muscles. The nerves grew into the muscles, which then allowed him to direct his senses through his own brain impulses. This is the first time a nerve-muscle graft has been used to connect an artificial limb. The arm is still experimental. It cost about $100,000 in materials but much more in research labor. The institute will be fitting a similar arm to a female veteran. A prosthetic leg may also be developed that would enable amputees to “feel” when they take steps. The institute also hope to help patients control wheelchairs through brain/machine interface and to communicate by typing messages with thought. Duke University researchers have discovered that two monkeys with neural implants enabling them to control remote robotic arms just by thinking, began to treat the robotic arms as if they were their own natural arms. While the animals were still able to use their own arms, some brain cells used to control them shifted to control the robotic arm instead. The animals could sometimes manipulate both their real arms and the robotic arm simultaneously. The researchers theorize that the higher primate brain “has extraordinary abilities to adapt to incorporate artificial tools, whether directly controlled by the brain or through the appendages,” and is “adaptable enough to incorporate any tools that we create to interact with the environment.” This adaptability is therefore “a fundamentally important property if brain-machine interface technology is to have any clinical future,” because it implies, first, that paralyzed people will in fact be able to adapt to operate external devices “with enough dexterity to make them really useful.” Second, it means that to be really useful, neuroprosthetics will have to be dexterous enough to give patients a full range of mobility in robot arms, hands, or other appendages. And third, it means that visual or tactile feedback mechanisms to enable the brain to perceive sensation from neuroprosthetic devices will be important to enhance people’s ability to learn and use the devices. The Neural Matrix CCD developed at the US Department of Energy’s Lawrence Berkeley National Laboratory (it won a 2005 “R&D 100” Award from R&D Magazine) is described as “the first step in creating combined biological and electronic chip implants that can provide neural networks of living, interconnected nerve cells for testing drugs and sensing toxins for homeland security — and, someday, restoring the use of limbs and eyesight and improved mental functions in patients.” The large arrays of networked neurons are made by coating the optical surface of a charge-coupled device (CCD) with diamond-like carbon, patterning it “in fine detail,” then coating it with a continuous layer of cell-culture collagen, and finally seeding it with neurons. The resulting CCDs have millions of individual sensors that can record changes in electrical potential from individual nerve cells in real time while precisely mapping each neuron’s activity within the neural network. Implanted Brain Cooler for Epilepsy A neocortical implant for severe epileptic patients is designed to detect the unusual level of electrical activity that accompanies severe seizures, and then cool a small area of the brain enough to render that part of the brain temporarily non-functional and seizure-free. The device has been successfully tested in rats by researchers at the Rensselaer Polytechnic Institute and Washington University School of Medicine, and has been approved by the US National Institutes of Health (NIH) for testing in primates. First Face Transplant Imminent Last Fall, the Cleveland Clinic became the first (and still the only) hospital to approve face transplants for patients with facial disfigurement caused by burns, trauma, disease or birth defects. Twelve potential recipients — five men and seven women — recently visited the Clinic for screening interviews. The surgical team has done extensive practice on animals and on human cadavers, and the microsurgery techniques needed are fairly standard today after more than a decade of use, but the procedure carries the extreme risk of rejection, leaving the patient probably more disfigured than ever. Standard plastic surgery, which tries to repair the disfigurement with the patient’s own skin can require dozens of operations and, while they may result in an improvement, they seldom if ever produce an aesthetically pleasing face, complete with the normal range of expressions. Patients often remain depressed or traumatized, so for them, a face transplant may seem a less ghoulish option than any alternative. The controversial and challenging (15-hours or longer) procedure involves removing the face — epidermis and underlying fat, nerves, and blood vessels (but no muscles) — from a cadaver and from the patient, then painstakingly reattaching the patient’s blood vessels and nerves to the transplant face. The patient will face the risk and cost (as much as US$1,000 per month or more) of immune suppression drugs, which may not even work in all cases, for the rest of his or her life, unless the Cleveland team’s success in shortening the drug regimen in rats can be made to work for humans too. A patient will probably not look like the donor after the procedure, unless by a remarkable coincidence they also had exactly the same skull size/shape and musculature. Transcranial Magnetic Stimulation A non-invasive, painless therapy called repetitive transcranial magnetic stimulation (rTMS) applied to the unaffected brain hemisphere of stroke patients appears to help them recover motor function. It appears to work by reducing activity in the healthy side of the brain, forcing the stroke-damaged side to work harder to compensate. The treatment involves sending a brief electrical current through an insulated wire coil on the scalp, which then sends a magnetic pulse into the cortex. Ten patients who had experienced a stroke within the previous 12 months and who were relearning to use their affected hands underwent three stimulation sessions an hour apart. They improved by as much as 50 percent on some of the tests, such as a reaction time test, compared with control patients receiving a sham treatment. The researchers also observed improved results on the Purdue Pegboard test, with a significant increase in the number of correctly placed pegs. Control subjects showed no changes in test performance over time. The improvements were only temporary; however, that may have been because the sessions were so few in number. The researchers believe that increasing the number of sessions will increase the duration and magnitude of the effect, and are planning further studies to test that hypothesis. Duke University scientists have grown new blood vessels with cells from sick older people. Blood vessels have previously been grown only from young, healthy cells. Such vessels could be used for heart and vascular arterial bypasses. In older people, leg veins are often in too poor condition to be used in the chest, or may been used up in previous bypass surgery, and available synthetic grafts are not very effective for small blood vessels. The vessels made by the Duke scientists were not strong enough to be implanted into people, a major hurdle. It could take up to 10 years further research before such vessels will be ready for use in people. Half the heart attacks in the US each year occur in people with normal cholesterol levels. The distribution of size, quantity, and type of lipoprotein particles provides a far better indicator than standard cholesterol tests of whether or not someone is at risk, and ion mobility analysis developed at the US Department of Energy’s Lawrence Berkeley National Laboratory does just that. It measures the size distribution and counts the number of individual particles in all classes of lipoproteins in the single step of dragging charged, aerosolized lipoproteins through air by the force of an electric field. It is a technology likely to find its way into routine clinical practice for the evaluation and management of risk for cardiovascular disease. A New Zealander, the first patient to be fitted with an assistive pump device designed to “turbocharge” a moderately ailing heart, was recovering in a hospital following surgery as of May this year. The “C-Pulse” implant comprises an inflatable polyurethane balloon held in place against the aorta by a polyester wrap. The balloon inflates in slightly delayed sync with the heartbeat, reinforcing the pumping action of a weakened heart by squeezing the aorta after it receives blood from the left ventricle (and after the aortic valve has closed) and propelling the blood with greater force down the artery and around the body. The balloon then deflates, and the cycle repeats. In a previous 20 minute test in six volunteers who were undergoing coronary bypass surgery, the C-Pulse increased blood flow in the left coronary artery by 67 percent. Its advantages over mechanical hearts and ventricular assist devices is that it does not involve the complicated surgery and clotting risks associated with plumbing directly into the bloodstream, and it is relatively easy to disconnect if the heart recovers its own strength — a good possibility given early enough intervention. Memory Restoration & Alzheimer’s A study in mice suggests that blocking the production of “tau” mutant protein in early stage Alzheimer’s could result in some recovery of memory. The method quite quickly restored memory in demented mice, but it remains years from use in people. Tau makes neurons sick, so if tau production is halted, the sick neurons have a chance to recover. Neurons that have already died obviously cannot recover, hence memory restoration can only be partial at best. In the study mice, memory function improved to about half the pre-demented state. Both tau and beta-amyloid cause tangles of plaque but it is suspected that it is the proteins themselves, not the plaque, that cause memory loss. Several drug companies are already looking for drugs to target amyloid production, and the new mouse study should stimulate efforts to find a tau blocker for humans also. Exoskeleton Nearly Ready for Market The first commercial version of HAL (Hybrid Assistive Limb), a robotic exoskeleton designed to help the elderly or disabled to walk or lift heavy objects is slated for release by the end of the year at a cost between US$14,000 and $19,000. Patients with brain and spinal injuries are also potential customers. The device straps onto the legs. Electric motors at the hips and knees provide power assistance for leg movements. A backpack holds a computer with a wireless network connection, and power comes from batteries on a belt. Bioelectric sensors attached to the skin on the legs detect an electric current that flows when the brain sends signals to the leg muscles. The computer translates the nerve signals into signals that control the motors of the exoskeleton, without appreciable delay, coordinates the movements caused by the motors, and records the posture and pattern of motion of the wearer. HAL can be calibrated to the individual user. New versions still under development provide power assistance to the arms, as well, enabling the wearer to lift up to 40 kilograms more than s/he might lift unaided. The new HALs also eliminate the backpack, with all electronics shrunk to fit on the belt, and less bulky motor housings. As a result, they are also lighter. However, even at 22 kilograms, the weight of the commercial version is not much of an issue since the device easily powers its own weight plus the wearer’s limbs. Eli Lilly’s experimental enzastaurin oral brain cancer drug was able to shrink glioblastoma tumors in 20 to 25 percent of 92 Phase II trial patients and stopped growth in another 10 percent. The trial patients had failed to respond to conventional chemotherapy and “were in very severe circumstances,” a Lilly spokesman said. Enzastaurin works by cutting off blood supply to the tumor and by disrupting cell pathway signaling vital to the survival of tumor cells. The trial patients took the drug for as long as they continued to respond to it, typically one to three months. It was well tolerated and the most common side effect was a low platelet count. Lilly hopes to get enzastaurin FDA-approved by 2008, and plans to test the drug against lung, colon, breast, and other cancers. An experimental drug called desmoteplase, based on a vampire bat protein, has shown promise in clearing away clots up to several hours after a stroke. The only approved clot-busting medication, TPA (tissue plasminogen activator), must be used within three hours after the onset of symptoms and fewer than four percent of stroke victims make it to the ER within that time. TPA also requires intravenous drip and takes up to an hour to dissolve larger clots, and it cannot be given to people prone to bleeding. Desmoteplase lasts longer, is easier to administer, and doesn’t seem to increase the risk of bleeding. It is a genetically engineered version of a protein in the saliva of the vampire bat. It is injectable and effective up to nine hours after the onset of symptoms, with a hemorrhage rate of two percent (compared to six percent for TPA). A Cleveland Clinic clinical trial of desmoteplase involving 38 stroke victims who didn’t get to the hospital within the three-hour time limit for TPA found that blood flow was restored in more than half of patients receiving the drug’s highest dose, compared to 38 percent in the placebo group. Three months after treatment, as many as 60 percent of patients who got desmoteplase were able to live independently, compared to 23 percent who had a dummy shot. A larger trial of 170 patients has begun. Canadian and US scientists have developed vaccines that protect monkeys, and may also protect humans, from the Marburg and Ebola viruses. It will take five or six years to complete the research to show the experimental vaccines can be safe and effective for people. “The data would suggest that instead of 100 percent chance of dying, they would have an 80 percent chance of survival,” a researcher told reporters. Patients suffering age-related macular degeneration who received Genentech’s experimental Lucentis drug in a recent trial had an average gain of seven letters on a standard eye chart, compared with a 10.5-letter loss for those given a placebo. Lucentis may reach the market in 2006. Glucon, Inc., has created a watch-like device that reads blood glucose levels without the need to draw blood. It contains a laser tuned to a frequency that resonates with blood glucose, creating sound waves that are detected by an ultrasound sensor and then translated into data by a computer chip. All of this technology is in a wristwatch-like device. Warnings such as “Sudden glucose drop!” appear on the faceplate. Glucon says its early tests show that it is as efficient as blood-strip tests but won’t release specific numbers before obtaining US Food and Drug Administration approval. If that is achieved, the device would revolutionize diabetes management for both the individual patient and the healthcare industry by reducing or eliminating mistakes in glucose monitoring and insulin administration, and thus reducing the incidence of insulin shock, diabetic coma, and diabetic blindness, as well as cutting emergency room visits. It appears to be the only totally non-invasive glucose monitor under development. A clinical trial is underway, and the device could be on the market within three years. A suitcase-sized hemodialysis machine is making daily at-home dialysis possible for a growing number of patients, improving their quality of life and resulting in lower costs through reduced hospitalizations. Home peritoneal dialysis, which uses the lining of the patient’s abdomen to filter out waste, has been available for some time but is only appropriate for a small percentage of patients and carries the risk of abdominal infections. Hemodialysis filters patients’ blood through a machine. The US Food and Drug Administration has approved two machines, weighing 300 pounds and 70 pounds, for daily home use. Trials of a third machine for home use have just begun. Medtronic Acquires Gastric Pacemaker Medtronic has acquired 10-year-old Transneuronix, and with it an implantable stomach pacemaker called the Transcend, designed to trick the stomach into telling the brain that it is full. The acquisition cost US$260 million, so Medtronic evidently sees major potential in the device as a treatment for obesity, a condition analysts view as a “hundreds of billions of dollars” market, reports the New York Times, and for overweight Type 2 diabetic patients in particular. The device was approved for sale in Europe in 2001 and Canada earlier this year. Early data appear to show that patients can lose 35 percent of excess weight, or about half as much as bypass surgery, whereas an existing FDA-approved obesity device, the inflatable Lap-Band which is positioned around the stomach, can help patients reduce excess weight by 50 percent. Presumably, Medtronic thinks the pacemaker’s effectiveness can be improved, or perhaps that it is ultimately more convenient than the Lap-Band. |
If you enjoyed this article, please consider sharing it!
