Helping the Paralyzed Walk

 

One of our primary goals at SBM is to advocate for high standards of science in medicine. This means that we spend a lot of our time discussing claims and practices that fall short of this standard. This is very useful – exploring exactly why a claim falls short is a great way to understand what the standard should be and why.

An unfortunate consequence of this approach, however, is that many of our articles tend to be negative. We focus on what doesn’t work, on what needs to be fixed, and on why people fail.

But there is a positive side to this story as well that we should not neglect – science is powerful and it works. That is why we are such enthusiastic advocates of science in medicine and why it is so important to get it right. We shy away from overhyping scientific advances in medicine, because the mainstream media does that so well, but every now and then it’s good to acknowledge some awesome medical scientific advance.

Hacking the Nervous System

A new report marks a notable advance in using both robotic technology and electrical stimulation to help a paralyzed man walk. Mark Pollock, described as a blind aventurer, broke his back four years ago after falling out of a window. He was completely paralyzed below the waste, with no voluntary movement. He has been working with the Edgerton Neuromuscular Research Laboratory at the University of California, Los Angeles. Dr. Reggie Edgerton has been working on spinal cord injury research for the past 30 years.

The new research combines two techniques. The first is electrical stimulation of the spinal cord. This is nothing short of a new paradigm in medical intervention.

There are several broad approaches to intervening in biological function. We can alter problematic anatomy and repair trauma through surgery or compensate with braces, prosthetics, and devices. We can alter physiology and biochemistry through pharmacological intervention. We can adjust physical activity, nutrition, and environmental exposures.

Added to this list is the use of electrical or magnetic stimulation to directly alter nervous system function. Electricity has been used to alter cardiac function, such as with a pacemaker. It has also been used to alter brain function for decades, going back to the beginning of electroconvulsive therapy. But that is a fairly crude and limited application of electrical stimulation. Electrical stimulation has also been used to modulate pain.

The last couple of decades has seen an increase in the sophistication and potential applications for electrical or magnetic stimulation. Combining this technology with computers and robotics has the potential to dramatically increase those applications.

Approaches to Paralysis

There are a number of ways we could potentially hack the nervous system in order to repair or replace function lost through injury. Several research teams are working on implanting electrodes onto the surface of the brain, or using scalp surface electrodes, in order to translate thought into computer control. Software interprets the brain signals, which the subject learns to control, enabling them to move a cursor on a screen, or control a robotic arm. This approach has the potential of bypassing any injury or paralysis and giving direct mental control to robotic limbs and devices.

Another approach is to attach electrodes to proximal muscles that are still under voluntary control and then connecting them to more distal muscles that have been paralyzed, or to robotic prosthetic limbs.

The robotics themselves can either take the form of a limb (such as a robotic arm) or an exoskeleton that fits over a patient’s arm or leg.

Edgerton’s team has been working on another approach entirely, specific to spinal cord injury. They use continuous low levels of electrical stimulation below the spinal cord injury to “wake up” the injured spinal network. The theory is that even with complete paralysis, there still may be some surviving connections and if they can be activated that can restore some voluntary control, even years after total paralysis.

They have been using two methods. The first involves surgically implanting electrodes epidurally – over the membrane that covers the spinal cord. The second is to use transdermal electrical stimulation, which stimulates across the skin and has the advantage of being noninvasive.

A couple years ago they reported on four subjects who were completely paralyzed after spinal cord injury who were able to have some restored voluntary control of their legs with this type of “holy grail” of spinal recovery, walking, but any movement was a proof of concept.

The New Advance

The latest report from Edgerton’s team is the result of a combination of transdermal electrical spinal cord stimulation and a robotic exoskeleton in Mark Polock. The exoskeleton is capable of supporting the patient’s weight and walking. The exoskeleton is also able to monitor any voluntary contribution to movement from the patient.

They were able to demonstrate that Pollock was voluntarily flexing his left knee and hips, contributing a little to the exoskeleton’s movement. He still needed assistance to walk, but this was a significant advance.

The reason it is beneficial for Pollock to contribute to the walking, rather than letting the exoskeleton do all the work, is that there are other health benefits. Paralysis can lead to lack of physical activity and cardiovascular disability. Voluntarily contracting muscles can improve muscle tone and function and improve cardiovascular health.

The Future

Combining robots, computer control, and electrically hacking the nervous system is still relatively new. This is often referred to as brain-machine or brain-machine-brain interface. There are also muscle/nerve-machine interfaces, and now we also have spinal cord-machine interface.

Obviously this is all a very new technology and we need to have realistic expectations of how long it will take for this technology to mature. There is a tendency to overestimate short term technological advances, and then become disappointed when the promised benefits do not manifest quickly. However, there is also a tendency to underestimate longer term advances. Then one day, the world changes rather quickly.

We are still years away from this technology going mainstream – getting it out of the research centers and into hospitals and regular practices. There are still technical issues to be worked out in terms of interfacing with the nervous system. But all of the proofs of concept are now in place. We really just need incremental technological advances.

It may take 10-20 years or even 30-40 years, but it seems likely that in something like that time frame we will see robotics and machine-nervous system interfaces essentially solve the problem of paralysis.

via Medicine Joint Channels

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The Science of Mom: A Science-Based Book about Baby Care

From the author’s website: “Shameless use of cute baby to promote book”

When a baby is born, parents are often awed and alarmed to find themselves responsible for this tiny new person, and they desperately want to do their very best to keep their infant safe and healthy. New mothers worry about everything from SIDS to vaccines, from feeding practices to sleep hygiene, and they are bombarded with conflicting advice about caring for their babies. Myths and misinformation abound. Finally someone has written a truly science-based guide to the first year of life: The Science of Mom.  The author is a research scientist with a PhD in nutritional biology. When her first child was born, she had a lot of questions, and thanks to her background she knew how to look for reliable answers in the scientific literature. She started writing the Science of Mom blog  and eventually turned her findings into a book.

Understanding science

Her first chapter covers the important concepts for understanding how to think about scientific studies:

• Good science is a process that takes lots of experiments, time, and people.
• Good science is peer-reviewed.
• One study on its own isn’t worth much, but scientific consensus is trustworthy.
• Some studies are more valuable than others (here she covers the various types of study from animal studies through observational studies in humans to RCTs and meta-analyses).
• Numbers matter (sample sizes).
• Don’t believe everything you read on the Internet (here she gives some practical tips for evaluating whether a website is reliable).
• Correlation is not causation (she uses my favorite example of the correlation between autism diagnoses and the sales of organic food).
• We can’t eliminate risks (but science can quantify the risks and benefits and families can use the information to decide what risks they are personally willing to take).
• Find smart allies (experts and providers you can trust).
• Forget about perfection and pay attention to your baby.

In subsequent chapters she delves into what science has to say about various topics. She finds that there is seldom a simple yes-or-no answer to these questions, and she presents the evidence on both sides fairly, adding a common-sense perspective.

When to cut the umbilical cord

There are clear benefits of delaying cord clamping, but there are also risks. We don’t know how long a delay is optimal. And there are practical problems like the logistics of resuscitating a baby in distress and of banking cord blood.

Vitamin K shots and eye goop

 She explains why newborns are given vitamin K injections, illustrating the danger of vitamin K deficiency bleeding (VKDB) with a horror story about a baby who nearly died from a brain bleed after the shot was inadvertently omitted. The evidence shows that oral supplements are not as effective, and that the injections are safe.

Antibiotic eye ointment is routinely used to prevent blindness and other complications of gonorrhea and chlamydia, but the incidence of gonorrhea in the population has declined. If a woman is at very low risk of sexually transmitted diseases, eye prophylaxis might reasonably be omitted; but when European countries tried doing it selectively instead of universally, the number of gonococcal infections in newborns rose. And the risks of treatment are minimal.

Breast is best

For some families, breast-feeding is clearly the best choice, but for others it isn’t. The benefits of breast-feeding have been hyped beyond the actual evidence. It is definitely beneficial; but the advantages are not huge, and formula feeding is a perfectly good option for mothers who can’t breastfeed or prefer not to. There are even some benefits to formula: it is fortified with iron, so bottle-fed babies are less likely to become anemic than breast-fed babies.

Bed sharing

There are benefits to keeping your baby close, but sleeping in the same bed is dangerous. She covers the published evidence, cultural differences, SIDS, factors that might have influenced study findings, and how to minimize the risks if you choose to co-sleep.

Sleep patterns

 One of the biggest problems for parents of newborns is chronic sleep deprivation. She covers the research on normal infant sleep patterns, arousability, and how infants learn self-soothing behaviors to fall asleep without help. Sleep training works, but not for all infants. It doesn’t harm babies, and it can help stressed parents get the sleep they need to be good parents.

Vaccines

 This chapter starts with an affecting personal story. One of the author’s uncles died at age 6 of encephalitis caused by measles. What had appeared to be a typically benign, uncomplicated case of measles suddenly turned deadly. The benefits of vaccines are undeniable. She shows the statistics for lives saved and she debunks many of the common anti-vaccine myths. She gives a lucid explanation of herd immunity. She recognizes that vaccines are not without risk, but the evidence shows that the risk is very small and the risks of not vaccinating are much greater. She explains how vaccines are rigorously tested and monitored for safety. She tells how the first rotavirus vaccine caused intussusception in a few recipients and how the system responded to create a safer vaccine. The new vaccine has prevented thousands of hospitalizations for rotavirus infection, and has even decreased the incidence of the disease in the unvaccinated through herd immunity.

When to start solid foods?

When I started practicing medicine we used to recommend starting rice cereal at 1 month so the solid food in the tummy would help the baby sleep through the night; it didn’t work. The evidence for when to start solid foods is conflicting, and there are confounding factors like varying hygiene practices and resources in different cultures. Starting between 4 and 6 months reduces the risk of anemia in breastfed babies and may reduce the risk of allergies, celiac disease, and type I diabetes. Starting at 6 months may lower the risk of diarrhea and the baby is more developmentally ready, making feeding easier. Waiting longer than 6 months is not advisable.

She says, “Take the focus off the calendar and put it where it belongs, with the little one doing the eating.” Babies develop at different rates and have different preferences. A baby is ready for solid food when he can be positioned upright for feeding, has lost the tongue thrust reflex that pushes the food right back out in younger babies, shows an interest in solid food, and can communicate when he doesn’t want something by closing his mouth or turning his head away.

Infant nutrition

Breast milk is the perfect food for newborns, but it becomes inadequate in later infancy. It fails to provide the iron that babies need to prevent anemia, and it is lacking in a number of nutrients like vitamins A, C, and E and micronutrients like zinc and manganese. Our ancestors probably overcame this by feeding older infants meat and other foods, and the evidence shows that meat, egg yolks, and fish are good for babies. Vegetarian diets, especially vegan and macrobiotic diets, have been shown to result in nutrient deficiencies, stunted growth, muscle and fat wasting, and slower psychomotor development.

The risk of anemia can be counteracted by feeding infant cereals fortified with iron. Whole grains may be more nutritious, but refined grain cereals are a better source of iron. She recommends feeding babies a varied diet, avoiding sugar, and not adding salt. She found no evidence that organic food benefited children’s health. She emphasizes that the most important part of feeding isn’t the food: parents should relax and enjoy feeding and interacting with their babies.

Babies are amazing

She includes a chapter that amounts to a love letter to babies, urging parents to observe how their newborns explore, communicate, and learn. Newborns have special reflexes and are capable of more than most people realize. And they are unique individuals; parents need to learn to interpret their cues and respond appropriately.

Appendixes

 In eight appendixes, she offers reassuring evidence-based answers to these questions:

• Are the ingredients in the vitamin K shot safe?
• Why is the HepB vaccine given at birth?
• Do we give too many vaccines too soon?
• Do vaccines cause autism?
• Do vaccines increase the risk of SIDS?
• Should we worry about the aluminum in vaccines?
• How do we know that babies need so much iron?
• Should we be concerned about arsenic in rice cereal?

Conclusion
This is science-based medicine writing at its best. Callahan doesn’t cherry-pick. She knows how to evaluate the entire body of research and put it into perspective along with practical parenting considerations. She enhances her message with a personal touch, including anecdotes about her own experiences as a new mother and about the experiences of her friends and family. If I had three thumbs, I would give this book a 3-thumbs-up recommendation. If every new parent could read this book, it would go a long way towards immunizing them against the misinformation they will inevitably encounter, misinformation that so often clouds their judgment and worries them unnecessarily.

 

via Medicine Joint Channels