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Do Blind People See Things in Their Dreams?

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A question from reader Josiah: "Do blind people see when they dream? I think there are two sides to the question, dealing with people who were born blind, and those who used to be able to see."

Whether visual imagery is present in the dreams of the blind has been pondered by scientists since the early 19th century. Josiah is right about that last part. People who are sighted, people who were born sighted but were blinded later in life, and people who were born blind all dream differently. As the Royal National Institute of the Blind in London puts it, "Dreams are experienced in the same way as life is lived." (Some people over 55 occasionally dream in black and white, while younger people who grew up with color television tend to dream only in color.1) How much visual imagery someone has experienced in their waking life—if they've experienced it at all—affects how much visual imagery is in their dreams.

A series of questionnaire and interview studies conducted in the 1970s2 led to four generalizations about the dreams of the blind:

1. People born blind, and who never experienced visual imagery in waking life, have no visual images in their dreams.

2. People who became blind before the age of five rarely experience visual imagery in their dreams.

3. People who became blind between the ages of five and seven sometimes retain some visual imagery and experience it in their dreams.

4. Most people who became blind after the age of seven continue to experience at least some visual imagery in their dreams, but the clarity and frequency of the imagery is often reduced with time.

Several studies in sleep laboratories, in which blind participants were woken up during REM sleep for the collection of dream reports, reported similar results.

A more recent study3 analyzed a sample of 372 dreams from 15 blind adults—some born blind, and others who went blind later in life. Again, the study found that people blind since birth or very early childhood experienced no visual imagery, and people blinded later in life did retain some visual imagery from their sighted waking lives and experienced it while dreaming.

One participant in the study, though, reported visual imagery inconsistent with the trends described in previous findings. Participant 13, a 24-year-old man blinded at age four, reported that he was able to see objects "clearly" or "plainly" during the dream, so it is possible that some people who became blind before the age of five can experience visual imagery in dreams.

The study also expanded upon the previous research and revealed two interesting things:

1. While less than one percent of sighted participants surveyed in two previous studies reported experiencing gustatory, olfactory, or tactual sensations in dreams, all but three of the blind participants in this study reported experiencing them. One participant, who has been blind since birth, reported that 48 percent of the sensations in his dreams were auditory and the other 52 percent were a mix of taste, smell and touch sensations.

2. Sixty percent of the blind men's dreams that involved locomotion or transportation, and 61% of the blind women's, had at least one incident of "dreamer-involved misfortune" (the norms for sighted men and women are 31 percent and 28 percent, respectively), which the researchers hypothesize is a continuation of the waking-life concerns that the blind have about getting from place to place.

1 Murzyn E. (2008). Do we only dream in colour? A comparison of reported dream colour in younger and older adults with different experiences of black and white media. Consciousness and cognition. Dec;17(4):1228-37.
2 Kirtley, D. (1975). The psychology of blindness. Chicago: Nelson-Hall.
3 Hurovitz, C., Dunn, S., Domhoff, G. W., & Fiss, H. (1999). The dreams of blind men and women: A replication and extension of previous findings. Dreaming. 9:183-193.

[Image courtesy of Christophe Moustier.]

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ETH Zurich
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This Soft Artificial Heart May One Day Shorten the Heart Transplant List
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ETH Zurich

If the heart in the Functional Materials Laboratory at ETH Zurich University were in a patient in an operating room, its vital signs would not be good. In fact, it would be in heart failure. Thankfully, it's not in a patient—and it's not even real. This heart is made of silicone.

Suspended in a metal frame and connected by tubes to trays of water standing in for blood, the silicone heart pumps water at a beat per second—a serious athlete's resting heart rate—in an approximation of the circulatory system. One valve is leaking, dripping onto the grate below, and the water bins are jerry-rigged with duct tape. If left to finish out its life to the final heartbeat, it would last for about 3000 beats before it ruptured. That's about 30 minutes—not long enough to finish an episode of Grey's Anatomy

Nicolas Cohrs, a bioengineering Ph.D. student from the university, admits that the artificial heart is usually in better shape. The one he holds in his hands—identical to the first—feels like taut but pliable muscle, and is intact and dry. He'd hoped to demonstrate a new and improved version of the heart, but that one is temporarily lost, likely hiding in a box somewhere at the airport in Tallinn, Estonia, where the researchers recently attended a symposium.

Taking place over the past three years, the experimental research is a part of Zurich Heart, a project involving 17 researchers from multiple institutions, including ETH, the University of Zurich, University Hospital of Zurich, and the German Heart Institute in Berlin, which has the largest artificial heart program in Europe.

A BRIDGE TO TRANSPLANT—OR TO DEATH

Heart failure occurs when the heart cannot pump enough blood and oxygen to support the organs; common causes are coronary heart disease, high blood pressure, and diabetes. It's a global pandemic, threatening 26 million people worldwide every year. More than a quarter of them are in the U.S. alone, and the numbers are rising.

It's a life-threatening disease, but depending on the severity of the condition at the time of diagnosis, it's not necessarily an immediate death sentence. About half of the people in the U.S. diagnosed with the disease die within five years. Right now in the U.S., there are nearly 4000 people on the national heart transplant list, but they're a select few; it's estimated that upwards of 100,000 people need a new heart. Worldwide, demand for a new heart greatly outpaces supply, and many people die waiting for one.

That's why Cohrs, co-researcher Anastasios Petrou, and their colleagues are attempting to create an artificial heart modeled after each patient's own heart that would, ideally, last for the rest of a person's life.

Mechanical assistance devices for failing hearts exist, but they have serious limitations. Doctors treating heart failure have two options: a pump placed next to the heart, generally on the left side, that pumps the blood for the heart (what's known as a left ventricular assist device, or LVAD), or a total artificial heart (TAH). There have been a few total artificial hearts over the years, and at least four others are in development right now in Europe and the U.S. But only one currently has FDA approval and CE marking (allowing its use in European Union countries): the SynCardia total artificial heart. It debuted in the early '90s, and since has been implanted in nearly 1600 people worldwide.

While all implants come with side effects, especially when the immune system grows hostile toward a foreign object in the body, a common problem with existing total artificial hearts is that they're composed of hard materials, which can cause blood to clot. Such clots can lead to thrombosis and strokes, so anyone with an artificial heart has to take anticoagulants. In fact, Cohrs tells Mental Floss, patients with some sort of artificial heart implant—either a LVAD or a TAH—die more frequently from a stroke or an infection than they do from the heart condition that led to the implant. Neurological damage and equipment breakdown are risky side effects as well.

These complications mean that total artificial hearts are "bridges"—either to a new heart, or to death. They're designed to extend the life of a critically ill patient long enough to get on (or to the top of) the heart transplant list, or, if they're not a candidate for transplant, to make the last few years of a person's life more functional. A Turkish patient currently holds the record for the longest time living with a SynCardia artificial heart: The implant has been in his chest for five years. Most TAH patients live at least one year, but survival rates drop off after that.

The ETH team set out to make an artificial heart that would be not a bridge, but a true replacement. "When we heard about these problems, we thought about how we can make an artificial heart that doesn't have side effects," he recalls.

USING AN ANCIENT TECHNIQUE TO MAKE A MODERN MARVEL

Using common computer assisted design (CAD) software, they designed an ersatz organ composed of soft material that hews closely to the composition, form, and function of the human heart. "Our working hypothesis is that when you have such a device which mimics the human heart in function and form, you will have less side effects," Cohrs says.

To create a heart, "we take a CT scan of a patient, then put it into a computer file and design the artificial heart around it in close resemblance to the patient's heart, so it always fits inside [the body]," Cohrs says.

But though it's modeled on a patient's heart and looks eerily like one, it's not identical to the real organ. For one thing, it can't move on its own, so the team had to make some modifications. They omitted the upper chambers, called atria, which collect and store blood, but included the lower chambers, called ventricles, which pump blood. In a real heart, the left and right sides are separated by the septum. Here, the team replaced the septum with an expansion chamber that is inflated and deflated with pressurized air. This action mimics heart muscle contractions that push blood from the heart.

The next step was to 3D-print a negative mold of the heart in ABS, a thermoplastic commonly used in 3D printing. It takes about 40 hours on the older-model 3D printers they have in the lab. They then filled this mold with the "heart" material—initially silicone—and let it cure for 36 hours, first at room temperature and then in an oven kept at a low temperature (about 150°F). The next day, they bathed it in a solvent of acetone, which dissolved the mold but left the printed heart alone. This process is essentially lost-wax casting, a technique used virtually unchanged for the past 4000 years to make metal objects, especially bronze. It takes about four days.

The resulting soft heart weighs about 13 ounces—about one-third more than an average adult heart (about 10 ounces). If implanted in a body, it would be sutured to the valves, arteries, and veins that bring blood through the body. Like existing ventricular assist devices and total artificial hearts on the market, it would be powered by a portable pneumatic driver worn externally by the patient.

FROM 3000 TO 1 MILLION HEARTBEATS

In April 2016, they did a feasibility test to see if their silicone organ could pump blood like a real heart. First they incorporated state-of-the-art artificial valves used every day in heart surgeries around the world. These would direct the flow of blood. Then, collaborating with a team of mechanical engineers from ETH, they placed the heart in a hybrid mock circulation machine, which measures and simulates the human cardiovascular system. "You can really measure the relevant data without having to put your heart into an animal," says Cohrs.

Here's what the test looked like.

"Our results were very nice," Cohrs says. "When you look at the pressure waveform in the aorta, it really looked like the pressure waveform from the human heart, so that blood flow is very comparable to the blood flow from a real human heart."

Their results were published earlier this year in the journal Artificial Organs.

But less promising was the number of heartbeats the heart lasted before rupturing under stress. (On repeated tests, the heart always ruptured in the same place: a weak point between the expansion chamber and the left ventricle where the membrane was apparently too thin.) With the average human heart beating 2.5 billion times in a lifetime, 3000 heartbeats wouldn't get a patient far.

But they're making progress. Since then, they've switched the heart material from silicone to a high-tech polymer. The latest version of the heart—one of which was stuck in that box in the Tallinn airport—lasts for 1 million heartbeats. That's an exponential increase from 3000—but it's still only about 10 days' worth of life.

Right now, the heart costs around $400 USD to produce, "but when you want to do it under conditions where you can manufacture a device where it can be implanted into a body, it will be much more expensive," Cohrs says.

The researchers know they're far from having produced an implantable TAH; this soft heart represents a new concept for future artificial heart development that could one day lead to transplant centers using widely available, easy-to-use design software and commercially available 3D-printers to create a personalized heart for each patient. This kind of artificial heart would be not a bridge to transplantation or, in a few short years, death, but one that would take a person through many years of life.

"My personal goal is to have an artificial heart where you don't have side effects and you don't have any heart problems anymore, so it would last pretty much forever," Cohrs says. Well, perhaps not forever: "An artificial heart valve last 15 years at the moment. Maybe something like that."

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5 Dubious Historical Antidotes for Poison (and What Actually Works)
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An artificial bezoar stone from Goa, India
Wellcome Images // CC BY 4.0

When it comes to their health, humans will believe just about anything. In this extract from the new book Quackery: A Brief History of the Worst Ways to Cure Everything, authors Lydia Kang, MD, and Nate Pedersen discuss some of the more questionable ways people once tried to protect themselves from poison—whether or not the methods actually worked.

Poison is everywhere. Naturally or unnaturally, it can be in the soil (arsenic), in the air (carbon monoxide), in your drinks (lead), and in your food (cyanide). With so much danger around, it’s no wonder humans have obsessed over finding a universal antidote—the one thing that could save us from all toxins. Imagine you’re a medieval prince about to inherit the throne. Chances are, there are a lot of power-hungry wannabes waiting in the wings. A little arsenic or hemlock might be your best friend or your worst nightmare. Just in case, best have an antidote on standby.

For millennia, a certain amount of magical thinking was employed when arming oneself against poison because science was inconveniently slow to catch up. So grab your handy unicorn horn and a bezoar, and let’s take a look.

1. BEZOARS

Bezoars have been used for centuries as antidotes to poisons. A bezoar is solid mass of undigested food, plant fibers, or hair found in the digestive tracts of animals, including deer, porcupines, fish, and, yes, humans. Anyone with a cat is familiar with the less-cool feline version: hairballs.

Bezoars and other stone-like items created by animals often had a good story behind them. Legends told of deer that would eat poisonous snakes and become immune or cry tears that solidified into poison-curing stones. First-century Arabic author al-Birumi claimed bezoars could protect against one poison called “the snot of Satan,” which we hope never ever to encounter. By the 12th century, when Europe became plagued with, uh, plagues, the bezoar crept into pharmacopeias as panaceas and alexipharmics (poison antidotes).

Bezoars were a seductive notion for the rich and royal, who were at risk of assassination. The stones were often enclosed in bejeweled gold for display or worn as amulets. Indian bezoars, in particular, were sought for life-threatening fevers, poisonous bites, bleeding, jaundice, and melancholy. Consumers were also known to scrape off a bit of bezoar and add it to their drinks for heart health and kidney stones. These tonics were sometimes adulterated with toxic mercury or antimony, which caused vomiting and diarrhea, making buyers think they were effective.

But were they? One team of researchers soaked bezoars in an arsenic-laced solution and found that the stones absorbed the arsenic or that the poison was neutralized. Hard to say if it worked well enough to cure a fatal dose. Ambroise Paré, one of the preeminent French physicians of the 16th century, was also a doubter. The king’s cook, who’d been stealing silver, was given the choice between hanging or being Paré’s lab rat. He chose the latter. After the cook consumed poison, Paré looked on as a bezoar was stuffed down his throat. Six hours later, he died wracked with pain. Perhaps he chose ... poorly?

2. MITHRIDATES

This antidote was named after Mithridates VI, the king of Pontus and Armenia Minor. Born in 134 BCE, he pretty much invented the phrase “what doesn’t kill you makes you stronger” by consuming poisons daily to prevent his own assassination. His royal home was stocked with stingray spines, toxic mushrooms, scorpions, mineral poisons, and a poisonous plant–filled garden. He was so unpoisonable that after his son took over his kingdom and he faced execution, he couldn’t even commit suicide by poison! He begged a guard to stab him to death. (It worked.)

Though the king’s actual recipe for the antidote is nowhere to be found, versions began to circulate after his death, and they became synonymous with the king himself. Compounds with lengthy and expensive ingredient lists prevailed, including iris, cardamom, anise, frankincense, myrrh, ginger, and saffron. In the first century, Pliny the Elder snarkily remarked, “The Mithridatic antidote is composed of fifty-four ingredients ... Which of the gods, in the name of Truth, fixed these absurd proportions? ... It is plainly a showy parade of the art, and a colossal boast of science.”

Showy or not, people would take the extensive mix of herbs, pound them together with honey, and eat a nut-sized portion to cure themselves. At least it endowed them with expensive-smelling breath.

3. HORNS

An apothecary shop sign in the shape of a unicorn
An ivory pharmacy sign in the shape of a unicorn's head
Wellcome Images // CC BY 4.0

Unicorn horns have been considered a part of antidote legend since the mythical beast galloped into literature around 300 BCE. For centuries afterward, real earthly beasts would sacrifice their lives and their horns to slake our thirst for the miraculous, nonexistent animal, including rhinoceroses, narwhals, and oryx. Even fossilized ammonites were used. It was believed that drinking vessels made of such horns might neutralize poisons, and wounds could be cured by holding them close by. In the 16th century, Mary, Queen of Scots reportedly used a unicorn horn to protect her from poisoning. Too bad it didn’t prevent her beheading.

4. PEARLS

Pearls have long been thought to be powerful antidotes. A beautiful, rare gem created by the homely oyster, a pearl is born out of annoyance (the mollusk secretes iridescent nacre to cover an irritant, like a parasite or grain of sand). Pretty as they are, they’re about as useful as the chalky antacid tablets on your bedside table; both are chiefly made of calcium carbonate. Good for a stomachache after some spicy food, but not exactly miraculous.

Pearl powder has been used in traditional Chinese medicine to treat a variety of diseases, and Ayurvedic physicians used it as an antidote in the Middle Ages. It was also reported to make people immortal. An old Taoist recipe recommended taking a long pearl and soaking it in malt, “serpent’s gall,” honeycomb, and pumice stone. When softened, it would be pulled like taffy and cut into bite-sized pieces to eat, and voilà! You would suddenly no longer need food to stay alive. Cleopatra famously drank down a large and costly pearl dissolved in wine vinegar, though in that case she wasn’t avoiding poison. She didn’t want to lose a bet with Antony—which might have fatally injured her pride.

5. THERIAC

Albarello vase for theriac, Italy, 1641
A vase for theriac, Italy, 1641
Wellcome Images // CC BY 4.0

Theriac was an herbal concoction created in the first century by Emperor Nero’s physician, Andromachus, who was reported to have Mithridates’s secret notes. It was a mashed formula of about 70 ingredients, including cinnamon, opium, rose, iris, lavender, and acacia in a honey base. In the 12th century, theriac made in Venice was branded as particularly special, and Venetian treacle (derived from a Middle English translation of theriac) became a hot commodity. Its public, dramatic production often attracted curious crowds.

By the 18th century, cheaper golden syrup was substituted for honey. As treacle began to lose its luster as a treatment, its definition as an herbal remedy disappeared from common vernacular. But the sweet syrup remained. Which is why when we think of treacle, we think of treacle tarts, not a fancy means of saving ourselves from a deathly poisoning.

BONUS: WHAT ACTUALLY WORKS

Thankfully, science has brought us a wide range of antidotes for many items we shouldn’t be exposed to in dangerous quantities, if at all. N-acetylcysteine, fondly referred to as NAC by doctors, saves us from acetaminophen overdoses. Ethanol can treat antifreeze poisoning. Atropine, ironically one of the main components of plants in the toxic nightshade family (such as mandrake), can treat poisoning from some dangerous fertilizers and chemical nerve agents used as weapons. For years, poisonings were treated with emetics, though it turns out that plain old carbon—in the form of activated charcoal—can adsorb poisons (the poisons stick to the surface of the charcoal) in the digestive system before they’re dissolved and digested by the body.

As long as the natural world and its humans keep making things to kill us off, we’ll keep developing methods to not die untimely deaths.

We’ll just leave the fancy hairballs off the list.

The cover of the book Quackery: A Brief History of the Worst Ways to Cure Everything
Workman Publishing

Excerpt from Quackery: A Brief History of the Worst Ways to Cure Everything by Lydia Kang, MD and Nate Pedersen/Workman Publishing. Used with permission.

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