Mind games: Strokes can rewire the brain
New accents, ‘face blindness’ among strange, rare syndromes
The first stroke hit Larry Guzik one early afternoon in July of 2008. He was only 40.
He had a second stroke two days later in hospital.
Soon after, a large chunk of his world went missing.
He couldn’t “see” people standing to the left of his hospital bed. He often missed food on the left side of his plate. He had trouble going through doorways in a wheelchair: he kept colliding with the left side of the door frames.
Out of hospital, after learning how to walk again, he once stepped into the path of a truck speeding toward an intersection from the left. The driver narrowly missed him.
Four out of 10 stroke patients will experience, to some degree, the bizarre syndrome known as hemispatial neglect. They’re not blind to what’s happening on one side of their world; their vision is commonly intact. They just don’t respond to one half of space, usually the left half. “They can see what’s there, but they don’t ‘represent’ what’s there,” says James Danckert, Canada Research Chair in cognitive neuroscience at the University of Waterloo. “They behave as if the left side of the world has simply ceased to exist.”
Many patients don’t know they have a problem.
Every 10 minutes in Canada, someone suffers a stroke, and while the physical impacts are often obvious and familiar — a limp, or a paralyzed arm — equally devastating are the hidden, cognitive disabilities that can convince some people they’re losing their minds.
After decades of neglect, science is beginning to unravel the strange, but fascinating, neuropsychological syndromes that can occur when neurons die and the brain tries frantically to rewire lost connections — conditions that will increase as the population ages, because one of the single biggest drivers of stroke risk is age.
This past summer, Canadian researchers described only the second known case of a patient who developed emotional synesthesia after stroke. Synesthetes can “taste” colours, hear sounds in response to smells, or “see” colours in response to letters or words. The word “cat,” to a synesthete, might look green.
This mixing of senses is extraordinarily rare, occurring, by some estimates, in fewer than one in 100,000 people. But it is just one of many examples of how a stroke-injured brain can behave in wild and fascinating ways. Other examples include:
Wernicke’s aphasia, an uncommon condition in which people still speak fluently and with a melodic rhythm, yet their sentences come out as a garbled, confused babble;
Prosopagnosia, so-called “face blindness,” the inability to recognize faces;
Foreign accent syndrome, a controversial and rare phenomenon, with fewer than 100 cases reported worldwide, including a Canadian. People with this syndrome experience “articulatory distortions” that make them sound as if they are speaking with an entirely new accent;
Capras syndrome, in which people develop the delusional belief that their relatives and friends have been replaced by doubles or impostors.
“For a lot of people who have these disorders, it’s very tough,” says Dr. Dale Corbett, scientific director and chief executive of the Heart and Stroke Foundation’s Centre for Stroke Recovery in Ottawa. “These problems are complicated. And the first conclusion you would come to is that they’re drunk, or stoned, or they’re demented, and it’s not that at all,” Corbett said. “We don’t fully understand what’s gone wrong in their brains.”
The brain is split into left and right hemispheres. The left side of the brain controls the right side of the body; the right controls the left. In the majority of people, the left hemisphere is important for language and speech, the right for reasoning, spatial and perceptual skills.
Most people recover well from minor strokes. But big strokes, in either hemisphere, can cause astonishing malfunctions.
WERNICKE’S APHASIA
Left-sided strokes can lead to aphasias — disorders affecting the ability to grasp language or speak. The most common is Broca’s aphasia. People know what they want to say, but they can’t express it. Their speech takes immense effort, and is telegraphic: “Go. Store. Me.”
Wernicke’s aphasia is entirely different. Asked “How are you today?” someone with Wernicke’s might say, “When? Easy for my river runs black boxes wizzel abata on when boobles come” — according to an actual case used in teaching.
“Normally, when we speak, the things we want to say, and the sentences we create, are created in Wernicke’s area toward the back of the brain,” says Dr. Robert Teasell, a professor in the department of physical medicine and rehabilitation at Western University in London, Ont. Wernicke’s area is connected to Broca’s area, at the front of the brain. Broca’s allows us to express what we want to say. “It’s the area that gets the language out,” Teasell says.
“If Wernicke’s area is damaged, but Broca’s is not, the person will just keep talking, but they’ll have no idea what they’re saying,” he said. “It sounds like speech. It just makes no sense at all.”
FOREIGN ACCENT SYNDROME
With foreign accent syndrome, language and speech aren’t a problem. People just sound entirely different.
In 2008, McMaster University researchers reported the case of a woman in Hamilton, Ont., who began speaking, according to how her family described it, “like a New found lander.” Rosemary Dore had lived her entire life in southern Ontario. New doctors would ask her if she came from “down East.”
Foreign accent syndrome, or FAS, is believed to result from damage to the basal ganglia located deep in the brain. The basal ganglia is involved in speech motor control. “It still sounds like speech. It’s just the finetuning that’s gone wrong somehow,” says Karin Humphreys, a cognitive psychologist at Hamilton’s McMaster University. Reported cases include a Scottish woman who began speaking in an Italian accent after a stroke, and an American woman from Indiana who developed an English cockney accent.
Still, FAS is controversial. Some say the person isn’t truly speaking in a genuine, new accent. Rather, it’s how the people around them are interpreting the changes in their timing, and intonation. “It sounds strange, and the way the human ears work, the way we listen to language, we put it in categories. We interpret everything that we hear,” Humphreys said.
Dore “ended up with a really good attitude about it,” Humphreys said. “She sort of realized, ‘I’m still here, and I’m still alive. Things could have been so much worse.’”
SPATIAL NEGLECT
For post-stroke patients with hemispatial neglect, “It’s truly as if their world is half the size of yours, and shifted to the right,” says Danckert, a professor of psychology at the University of Waterloo.
Neglect is most commonly caused by a stroke in the middle cerebral artery in the brain’s right hemisphere, Danckert says. The middle cerebral artery supplies blood and oxygen to a large chunk of the outside of the brain, which includes motor and sensory areas.
“It affects every part of their lives,” Danckert says. “They can’t navigate even their own homes well. They bump into things, and knock things over. They can’t drive.” Some patients comb only half their hair, or they leave the left sleeve hanging when they put on a shirt or coat. Some stop using their left arm or hand entirely, as if it were paralyzed or no longer there.
Dr. David Butler-Jones, the man who led the country through the H1N1 flu scare and who announced in July he was stepping down as Canada’s chief public health officer, experienced a milder form of neglect following his stroke a year ago. He says it felt as if his left side “was separate from me,” as if it had its own consciousness. If he closed his eyes, he would fall over. “It’s much improved,” he adds. He no longer trips over or bumps into things. “But when I get tired, when I get mentally tired, my left side goes wonky again.” He leans to the left; his head tilts. “What I was told was, it will never be completely gone. … I don’t think I’ve had anything more challenging in my life than recovery.”
Five years after his stroke, Larry Guzik’s neglect has improved considerably. But it still waxes and wanes. Whenever the man from Kitchener, Ont., starts to feel overwhelmed by details, or “a little bit lost,” he hears his occupational therapist’s voice in his head: “Left to right, top to bottom.” Neglect patients are taught how to constantly scan their environments, like the beacon from a lighthouse.
“I have to be very conscious about applying that, about paying attention to the left, turning my head — whatever I have to do to focus on what’s on the left,” he said. He describes his neglect as if a “slice of pie, a section of my peripheral vision is just not there.” A graphic designer, Guzik hasn’t been able to return to work yet.
Focusing remains a challenge, and he still experiences some “inattention” on his life side.
“There’s definitely sensation loss,” he says. “It’s a process of working with what I have and getting used to my body, just coming to accept the result of the brain injury,” he says. “It’s really demonstrated to me how resourceful a person I am.”
PROSOPAGNOSIA
In more rare cases, people lose more than a sense of space after a stroke. They lose the ability to recognize faces. People with prosopagnosia — “face blindness” — see the individual bits: the eyes, mouths and chins. They just can’t put the pieces together into a full form, says Bradley Duchaine, an associate professor of psychological and brain sciences at Dartmouth College in Hanover, N.H.
With stroke, the condition is believed to result from damage to brain cells in the temporal lobe that are exquisitely specialized for a single task: processing faces.
“If you think of how we evolved; we evolved from apes. Facial gestures were really important in deciding whether to fight or run,” said Corbett, of the Centre for Stroke Recovery. “So the brain evolved to recognize, and put a lot of emphasis, on facial features.”
For some prosopagnosics, faces are blurry or distorted, as if they’re being reflected in funhouse mirrors. For others, “When they look at an upright face, it’s similar to what you and I experience when we look at an inverted face,” Duchaine said.
Famed neurologist Oliver Sacks, author of The Man Who Mistook His Wife for a Hat, has suffered from prosopagnosia for as long as he can remember. He told an interviewer how he once caught himself grooming his beard in what he thought was his reflection in a restaurant window as he sat at an outside table. He then realized he was “preening myself” in front of a grey-bearded man staring back at him from the other side of the window.
Prosopagnosics are taught how to lock in on other cues to help recognize faces: voices, perfumes, unusually large noses or distinctive hairstyles, for example. Even then, most strokes don’t lead to prosopagnosia, Duchaine stressed. “You’ve got to have a stroke in the right place.”
Calgary neurologist Dr. Michael Hill once treated an accountant who had a stroke while working on someone’s taxes. He can no longer add columns of numbers, a condition known as “dyscalculia.” “He can say, ‘That’s 32 and 44 and 33.’ He just can no longer do the addition,” Hill says. Another patient suffered a stroke while reading the newspaper. He could no longer read, but he could still write, a “disconnection syndrome” called “alexia without agraphia.” He couldn’t transfer the words he was reading over to his brain’s language area for decoding.
People can learn to adapt to their new lives. And scientists are discovering just how extraordinary the brain’s capacity is to rewire and heal itself, experts say.
“The brain is so fascinating, and so complicated,” said Corbett. With the right therapy, people will often continue to recover “long past what we would have normally expected.”