Friday, March 28, 2014

Measuring the Severity of Head Impacts in Sports

It’s well known that repeated high-impact collisions in sports can cause acute concussive brain injury and even permanent brain damage. Unfortunately, there aren’t any simple quantitative tests to determine precisely who has suffered too many high-impact blows to the head. How severe does an impact have to be to cause injury? And how many moderate impacts are too many?

Devices designed to measure the relative severity and direction of head impacts may soon yield some answers. Already, at least one commercial product is available. The Checklight by Reebok is a relatively inexpensive monitoring device embedded into a skullcap that can be worn under a helmet. The Checklight combines a series of three accelerometers (to measure g-forces) with a gyroscope (to measure direction). A mathematical algorithm crunches the numbers and comes up with a relative measure of impact intensity. A green light on the device turns to yellow after a moderate impact and red after a more severe one.

But what do the indicator lights really mean? Reebok is careful not to call the Checklight a device for determining who has actually suffered a concussive blow to the head. They call it a “conversation starter”, meaning that it may allow coaches and medical personnel to decide who might need to be evaluated carefully by a medical professional. There is general agreement that more research is needed before these types of devices could be used to truly define who has suffered a concussion.

Some people worry that the device might lead to a false sense of complacency if too much reliance is placed on it. Others argue that we should be looking for ways to reduce the number and severity of head impacts in sports, instead of looking for better ways to determine who might be at risk of a concussion so that we can bench them. Still, it’s encouraging to see research-and-development efforts like this one being undertaken. There’s no reason we can’t take both approaches at once.

The Checklight is meant to be worn under a helmet. Researchers are working on similar impact-measuring devices that can be incorporated into a headband, for use in sports that don’t use helmets.

For more on this subject, go to a previous blog post titled "Diagnosing Concussions in Athletes Quickly and Inexpensively."

Sunday, March 23, 2014

A Blood Test to Predict Alzheimer’s Disease

The news media made a big deal this month of the finding that a blood test has been developed that can predict (with 90% accuracy in persons over 70 years of age) who will develop Alzheimer’s disease within the next two to three years. A representative news article is this one, by NPR.

The development of a blood test to predict who is likely to develop Alzheimer’s disease sounds like a major breakthrough until you realize that at the moment there is no way to prevent Alzheimer’s from developing, and no cure once you have it. That raises an interesting dilemma; if you’re not going to benefit from being tested (prevention or cure), why be tested? Would you want to know you’re going to develop Alzheimer’s if there was nothing you could do about it except get your affairs in order?

One other fact to consider: there’s no evidence that the test can predict 40, 20, or even 10 years in advance who will get Alzheimer’s disease. The test has only been proven to be accurate within 2-3 years of the onset of Alzheimer’s. You’d have to get the test every year just to know that you were about to develop Alzheimer’s very soon. What would be the total cost of a test every year for a lifetime? The biggest beneficiaries would be your doctor and the blood-testing company.

The new test will certainly benefit researchers searching for ways to prevent Alzheimer’s, though. That’s because it will allow researchers to test potential preventative measures on people who are almost certain to get Alzheimer’s disease (as determined by the test) before the disease actually develops. That is, provided that people are willing to be tested and then to join a research study if they test positive.

Tuesday, March 18, 2014

Economic Theory is Applied to Kidney Donations

In 2012 the Nobel prize in economics was awarded to economist Alvin Roth and mathematician Lloyd Shapley, for their work in developing algorithms for efficient computerized matching of individuals with unique needs with other similar individuals or institutions. Their algorithms have been used to match employers with employees; hospitals with doctors seeking residencies; students with schools; even kidney donors with kidney recipients.

That’s right; kidneys. Matching donors to recipients is not all that easy, because although a donor may want to donate to a specific recipient (say a relative, or a spouse), often they can’t because the tissue match is not good enough. That’s where Dr. Roth and his computer algorithm come in. By entering all available potential donors and recipients into a computer file and then applying a matching algorithm based on each donor and recipient’s tissue type, the best possible match can be found for each donor and for each recipient, even though they might not even be aware of each other. The donor may end up donating to an unknown and unrelated recipient, but in exchange the recipient will get a kidney from another, also unrelated, donor. The effect is the same as if the donor had donated directly to his/her specific recipient of choice!

Dr. Roth’s matching algorithm was first applied to kidney donations back in 2004 by the New England Program for Kidney Exchange (NEPKE). The method worked so well that NEPKE was later folded into the current national kidney matching system, United Network for Organ Sharing (UNOS). Since 2004 Dr. Roth’s method of matching has resulted in over 2,000 kidney donations, most of them between unrelated donors and recipients.

Thursday, March 13, 2014

A Skin Patch to Deliver the Flu Vaccine

What if you could get the flu vaccine in the form of a small patch that you could apply on your own, without having to go to a health professional? Perhaps you could even buy the flu patch over the Internet and have it mailed to your home!

That future may not be that far off, according to researchers at the Georgia Institute of Technology and Emory University. They’ve developed a small patch with 50 tiny dissolvable needles that penetrate into the deeper layers of the skin. The patch itself (without vaccine) has been tested extensively on human volunteers, according to an article in the April 1 issue of Vaccine (pp. 1856-1862). An abstract of the article can be viewed here.

Clinical trials with patches loaded with vaccine may begin as early as next year. Provided it works, the flu patch could become available within a couple more years. Think of it. No trip to a health facility for an annual flu shot. No needle and no muscle soreness later. Cheaper, more convenient, and less painful – what’s not to love about that?

Sunday, March 9, 2014

Acetaminophen May Affect Fetal Development

A Danish study of over 64,000 women has revealed that women who take acetaminophen during pregnancy may (and I stress “may”) increase the risk of their child being diagnosed with ADHD (Attention Deficit Hyperactivity Disorder).  The data show “an association” between childhood diagnoses of ADHD and the intensity and timing of acetaminophen use during pregnancy.  Heavy acetaminophen use, particularly during the second trimester of pregnancy, showed the greatest effect.

Acetaminophen, the active ingredient in Tylenol and Excedrin, is thought to be one of the safest painkillers there is.   It has had a good record of safety for many years.   Health professionals stress that this study alone, while worth paying attention to, is not enough to cause acetaminophen to be banned outright.  It’s worth reiterating what you already know from your basic science education; an “association” (or correlation) does not prove cause-and-effect.  Even the authors of the study stress that further study is warranted before any drastic action is taken.

Acetaminophen has some very important positive actions in addition to pain suppression.   Most importantly, it can lower a fever.  Until more is known about acetaminophen and fetal development, doctors suggest that pregnant women simply reduce their acetaminophen use to a minimum; use it for lowering a fever, but not for minor aches and pains.

Tuesday, March 4, 2014

Multivitamins Should Be Avoided

Trace amounts of vitamins are essential to good health. As our knowledge of the roles that vitamins play in maintaining good health grew, so too did the multivitamins industry, to the tune of tens of billions of dollars a year. Before long we were all being urged to make sure we were getting our daily dose of vitamins. To make sure we all bought in to the hype, vitamin marketers even designed specialized “age-adjusted” multivitamin combinations, such as Centra Silver (for adults over 50) and Flintstones vitamins (for children).

But are vitamin supplements really necessary? Not everyone thought so. Two years ago a Mayo Clinic physician advised that “Multivitamins aren’t necessary for healthy children who are growing normally.”

Two new clinical trials and a recently-published review of 27 previous vitamin studies all support the conclusion that multivitamin supplements are not necessary for well-nourished people. In fact, too much of some vitamins, most notably beta-carotene, vitamin E and perhaps vitamin A, can be harmful. The latest research, published in the Annals of Internal Medicine, signals a major shift in the philosophy of multivitamin use, from “You should take them, just to be sure.” to “In well-nourished individuals, they may do more harm than good.” According to the editorial in the same journal, the use of vitamin supplements by healthy individuals is not justified and should be avoided. Avoided.

That’s not to say that vitamins should never be taken as supplements. Individuals who have been tested and are known to be deficient in vitamins should take them, of course. But a person in good health should spend his/her money on something else.

It’ll be interesting to see how the multivitamin industry reacts to these findings.

Sunday, March 2, 2014

Earth’s Largest Mass Extinction Occurred Quickly

Planet Earth has experienced at least five mass extinctions over the past 500 million years or so. The largest mass extinction, marking the boundary between the Permian and Triassic periods, resulted in the loss of close to 95% of all species of organisms living at the time.

Until recently it has not been possible to determine exactly when the mass extinction occurred or how long it lasted. But now, using better dating techniques, scientists have pinpointed the Earth’s largest mass extinction more precisely, to between 251.88 and 251.94 million years ago. That’s a duration of just 60,000 years (0.06 million years); much shorter than previously thought. What could have caused such a rapid and devastating die-off? Scientists don’t know for sure, but it’s worth noting that the extinction coincided with a massive rise in atmospheric CO2 levels to over 2,000 parts/million (ppm), perhaps due to a period of increased volcanic activity. That in turn may have caused a substantial global warming, including warming of the oceans.

Some people think that as a result of human activity (the release of CO2 into the atmosphere as the result of the burning of fossil fuels) we may be at the beginning of a new period of mass extinction. Its worth noting that atmospheric CO2 levels are currently around 390 ppm, clearly up from 280 ppm before the industrial revolution but nowhere near the levels seen in the last extinction. Is that good news, or bad? No one knows for sure. In another 60,000 years we might know the answer, but by then it would be too late.

You and I will be long gone by then….