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How Removing Half of Someone's Brain Can Improve Their Life

From the outside, Elena del Peral seems to be like any other high-achieving college senior. She goofs around the campus quad of Massachusetts’ Curry College with her classmates and posts pictures on Facebook of birthday drinks with girlfriends. She holds a philanthropic job at a childhood cancer foundation and is on the dean’s list. She's friendly, bright, and fit. Outwardly, perhaps the most provocative thing about her is that she’ll wear both a Yankees cap and a Red Sox jersey at the same time—a peacemaker among the long-standing rivals. 

But beneath her cap is one remarkable mind. Elena del Peral has only half a brain.

Image courtesy of Elena del Peral

Shortly after her birth in 1992, Elena’s parents started to notice that she was favoring her right side. By the time she was a toddler, she was solely using her left arm to shimmy along the floor, with her right arm tucked in to her chest. Within 18 months she began to suffer severe seizures, and at age two she had a massive tonic-clonic episode while vacationing in the Adirondack Mountains. Desperate to determine what was causing these intractable seizures and the hemiparesis, her parents, Sonya and Casiano, jockeyed from specialist to specialist throughout the northeast.

It turns out that Elena had suffered a left-sided congenital stroke in utero, which was sparking electric storms in her brain that spread from the diseased area across the corpus callosum—the great communicator between the two cerebral hemispheres—to the healthy right side of her brain. For the next four years, she took every epileptic medication in the book. They dulled her senses but didn’t stop the seizures.

At age six, del Peral underwent a battery of tests including MRIs, EEGs, and CAT scans. A team including neurologists and neurosurgeons pored over the results. They said her condition fit the criteria for a rare surgery that seemed radical but had yielded promising results in the past for people like her. It was called a hemispherectomy: “hemisphere,” half the brain; “-ectomy,” surgically removing it. In short, they wanted to remove half of Elena’s brain.

Dr. Howard Weiner, a pediatric neurosurgeon and professor of neurological surgery and pediatrics at the NYU Langone Medical Center and NYU School of Medicine, has been performing these types of surgeries on children for decades—including on Elena. He explained to mental_floss­ that when it comes to cases like hers, the normal part of the brain is impaired when it is bombarded by overly active impulses sent over from the damaged side. These children can suffer cognitive developmental impairment, partial paralysis, behavioral issues, social isolation, and a laundry list of other problems. Once that transmission is cut, the unharmed hemisphere can start functioning without all of that charged disruption.

Soon after, Weiner performed a left-sided hemispherectomy on Elena, removing the left half of her brain. Recovery after a hemispherectomy is very positive. With aggressive occupational therapy and physical therapy, children can usually lead normal, productive lives. Elena recalls to mental_floss, “Things suddenly got easy. I became smart. I made friends. I became social. I just need a little extra help.”

Her parents capitalized on her go-getter attitude and inner motivation. She attended special programs for children with disabilities and then attended Darrow School, a co-ed boarding school in New York, where her talents were fostered. Over the years, she excelled.

A BRAVE NEW BRAIN SURGERY

The first hemispherectomies—at least ones that patients actually survived—date back to the 1920s, when neurosurgery pioneer Walter Dandy removed entire halves of the brain to treat cerebral glioma, a type of brain tumor. In 1938, Canadian neurosurgeon K.G. McKenzie performed a similar procedure to treat a patient with left hemiplegia (paralysis on the left side of the body) and epilepsy; the patient's seizures eased after the right hemisphere was removed. Various techniques have been performed over the years, from cutting out small portions of the afflicted area to removing entire hemispheres.

In the past 25 years, the procedure has evolved, thanks to a better understanding of complications such as hydrocephalus, an abnormal accumulation of cerebral spinal fluid in the empty part of the brain cavity; improved surgical methods to prevent recurring seizures; accurate mapping and isolation of the unhealthy area; and a deeper knowledge of the brain’s plasticity. In fact, 2016 Republican presidential candidate and pediatric neurosurgeon Ben Carson revived the surgery in the 1980s at Johns Hopkins Hospital—the very hospital where Dandy operated.

But we have to look back to the 19th century to understand why we ever thought taking away half a patient’s brain might make her better off—and specifically to Phineas Gage, perhaps neuroscience’s most famous patient, who clued us in to the remarkable resiliency and adaptability of the human brain. In 1848, while he was working on a railroad-building site in Vermont, an explosion blasted a 43-inch tamping iron through Gage’s head, entering through his left cheek and exiting straight out of the top of his head.

Not only did Gage live to tell the tale, but he had a relatively normal life for another 12 years, working as a stagecoach driver in Chile before returning to San Francisco to live with relatives. Gage had some neurological deficits and major personality changes—he became an avid user of profanity and had little sense of social propriety, among other things—but various reports suggest that, all in all, his brain regained much of its function. In this studio portrait, Gage is said to be holding the iron rod that pierced his skull.

Gage’s case is only one of several historical incidents in which individuals sustained massive brain injuries yet largely recovered. Immensely complex, the brain is more than a collection of neurons and glial cells. It is the body’s primary controller, with highly specialized areas wired to command thoughts, movement, and action. For example, Broca’s area, located in the frontal lobe of the left hemisphere, controls the ability to speak. But the brain compensates. Despite the left side of her brain being gone, del Peral speaks without any difficulty—and quite eloquently.

Gage's and del Peral’s cases are prime examples of neuroplasticity, the brain’s ability to rewire networks and reorganize cellular or neural function to take place somewhere else.

“Language sets up shop by age two, three, and four, at which time we are learning how to speak,” Dr. Weiner says. “When the area that controls language is damaged, it can move. The earlier the insult, the more likely it is to move—the more plasticity.” That’s what happened in del Peral’s case. The left side of her brain was damaged in the womb, so language and motor function shifted to the right side before she was even born. At the time of her surgery, the left side of her brain, the source of her epilepsy, was doing more harm than good.

HOPE FOR QUIETING THE ELECTRICAL STORM

Hemispherectomies can reduce or eliminate seizures up to 89 percent of the time in children with certain neurological disorders, including infarcts (brain necrosis), malformations of the cortical development, Rasmussen’s encephalitis (an inflammatory condition that attacks only half of the brain), and Sturge-Weber syndrome (a vascular abnormality).

The trend now is to perform the surgery on younger children, and even babies, to take advantage of the brain’s plasticity as early as possible. For example, if the left hemisphere is removed around age 10 or after, the child will likely never speak again, as speech is already fixed.

Today, the operation can be much less invasive, with more vascularized brain left intact. In fact, surgeons are increasingly referring to the procedure as a hemispherotomy because they may not have to remove an entire half of the brain. In one diagnostic test, subdural electrode grids are surgically applied before the actual hemispherectomy in order to help neurologists and neurosurgeons map out the bad tissue. Once surgery begins and the brain is exposed, they work carefully from the inside out, following the corpus callosum to then functionally disconnect the communication link between the two halves of the brain. Highly technical microscopes and micro-surgical instruments—wielded with a lot of skill—are used to excise the problematic matter. Any hole that is left naturally fills in with cerebral spinal fluid, which protects the tissue left inside.

Disconnect is the key word,” says Dr. Weiner. “We went from resecting [complete removal] to simply disconnecting.”

By disengaging the damaged portion of the brain, the electrical storms stop traveling to the healthy side of the brain. Many patients like Elena can stop having seizures altogether and cease taking epileptic medications for good.

According to data collected by the Kids' Inpatient Database (KID) every three years from 2000 to 2009, 552 hospital admissions were documented for hemispherectomies in the U.S. during that time period, with a mean patient age of 6.7 years old. Currently, approximately 42 hospitals in the United States and 13 facilities abroad perform the surgery. The demand outpaces the supply; at the time he spoke to mental_floss, Dr. Weiner was en route to Panama to operate on children with intractable seizures.

Next spring, del Peral will graduate from Curry College, where she has made the dean’s list every semester since freshman year. “I have to work 10 times more than the average person, but it’s worth it,” she says. “No one has a story like mine. Living with half a brain? I don’t want this to define who I am.”

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Brain Training Could Help Combat Hearing Loss, Study Suggests
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iStock

Contrary to what you might think, the hearing loss that accompanies getting older isn't entirely about your ears. Studies have found that as people get older, the parts of their brain that process speech slow down, and it becomes especially difficult to isolate one voice in a noisy environment. New research suggests there may be a way to help older people hear better: brain training.

The Verge reports that a new double-blind study published in Current Biology suggests that a video game could help older people improve their hearing ability. Though the study was too small to be conclusive, the results are notable in the wake of several large studies in the past few years that found that the brain-training games on apps like Luminosity don't improve cognitive skills in the real world. Most research on brain training games has found that while you might get better at the game, you probably won't be able to translate that skill to your real life.

In the current study, the researchers recruited 24 older adults, all of whom were long-term hearing-aid users, for eight weeks of video game training. The average age was 70. Musical training has been associated with stronger audio perception, so half of the participants were asked to play a game that asked them to identify subtle changes in tones—like you would hear in a piece of music—in order to piece together a puzzle, and the other half played a placebo game designed to test their memory. In the former, as the levels got more difficult, the background noise got louder. The researchers compare the task to a violinist tuning out the rest of the orchestra in order to listen to just their own instrument.

After eight weeks of playing their respective games around three-and-a-half hours a week, the group that played the placebo memory game didn't perform any better on a speech perception test that asked participants to identify sentences or words amid competing voices. But those who played the tone-changing puzzle game saw significant improvement in their ability to process speech in noise conditions close to what you'd hear in an average restaurant. The tone puzzle group were able to accurately identify 25 percent more words against loud background noise than before their training.

The training was more successful for some participants than others, and since this is only one small study, it's possible that as this kind of research progresses, researchers might find a more effective game design for this purpose. But the study shows that in specific instances, brain training games can benefit users. This kind of game can't eliminate the need for hearing aids, but it can help improve speech recognition in situations where hearing aids often fail (e.g., when there is more than one voice speaking). However, once the participants stopped playing the game for a few months, their gains disappeared, indicating that it would have to be a regular practice.

[h/t The Verge]

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This Virtual Reality Game Is Designed to Help Scientists Spot Dementia
Deutsche Telekom
Deutsche Telekom

There’s a new reason to enter virtual reality, and it’s not to play ping pong or check the weather. A game designed to help diagnose dementia is coming to virtual reality, as CNET and the BBC report.

Sea Hero Quest, a game designed to test players’ ability to navigate, is now available for Oculus and Samsung Gear. Trouble navigating is one of the first signs of dementia, and the game (which was created by neuroscientists and funded by Deutsche Telekom) collects anonymous data on users’ ability to navigate through complicated pathways while captaining a virtual boat. It’s not designed specifically to be played by people with dementia, but rather to test the navigational skills of the population as a whole. The goal is to eventually be able to diagnose dementia far earlier than currently possible, perhaps by as much as 15 years.

Sea Hero Quest already claims to be the largest dementia study in history, with 3 million players so far. It can generate 15 times more data in virtual reality than in the mobile game, according to its developers, because it can capture eye-tracking movements and the movements of the boat within the game. Virtual reality can also support established tests developed for lab settings, like the often-used spatial learning task known as the Morris water maze.

The addition of virtual reality makes the process that much faster, adding a much larger dataset to what the scientists are already working on. They estimate that two minutes of gameplay generates the same amount of data as five hours in the lab.

This isn’t the first scientific foray into virtual reality. Researchers are also using it to explore sites for jaguar habitats, among other applications.

[h/t CNET]

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