Perinatal stroke

Helen Santoro

I barreled into the world — a precipitous birth, the doctors called it — at a New York City hospital in the dead of night.

In my first few hours of life, after six bouts of halted breathing, the doctors rushed me to the neonatal intensive care unit. A medical intern stuck his pinkie into my mouth to test the newborn reflex to suck. I didn’t suck hard enough. So they rolled my pink, 7-pound-11-ounce body into a brain scanner.

Lo and behold, there was a huge hole on the left side, just above my ear. I was missing the left temporal lobe, a region of the brain involved in a wide variety of behaviors, from memory to the recognition of emotions, and considered especially crucial for language.-

My mother, exhausted from the labor, remembers waking up after sunrise to a neurologist, pediatrician and midwife standing at the foot of her bed. They explained that my brain had bled in her uterus, a condition called a perinatal stroke.

They told her I would never speak and would need to be institutionalized. The neurologist brought her arms up to her chest and contorted her wrists to illustrate the physical disability I would be likely to develop.

In those early days of my life, my parents wrung their hands wondering what my life, and theirs, would look like. Eager to find answers, they enrolled me in a research project at New York University tracking the developmental effects of perinatal strokes.

But month after month, I surprised the experts, meeting all of the typical milestones of children my age. I enrolled in regular schools, excelled in sports and academics. The language skills the doctors were most worried about at my birth — speaking, reading and writing — turned out to be my professional passions.

My case is highly unusual but not unique. Scientists estimate that thousands of people are, like me, living normal lives despite missing large chunks of our brains. Our myriad networks of neurons have managed to rewire themselves over time. But how?

‘The Worst Participant’

My childhood memories are filled with researchers following me around with pens and clipboards. My brain was scanned several times a year, and I was tasked with various puzzles, word searches and picture-recognition tests. At the end of each day of testing, the researchers would give me a sticker, which I would keep in a tin container next to my bed.

When I was around 9 years old, researchers wanted to see how my brain would act when I was exhausted. I would sometimes stay up all night with my mom, eating Chinese food and watching Katharine Hepburn and Spencer Tracy movies. The next day I would stumble into the clinic half-awake, and scientists would stick electrodes on my scalp. As long wires fell from my head like Medusa’s snakes, I was finally allowed to fall asleep, blissfully unaware that the researchers were searching for abnormalities in my brain waves.

Over the years, the scientists realized that I wasn’t like the other children in the study: I didn’t have any deficits to track over time. When I was around 15, my dad and I met in the cluttered Manhattan office of Dr. Ruth Nass, the pediatric neurologist leading the research. She questioned if I had actually had a perinatal stroke. In any case, she said frankly that my brain was so different from the others’ that I could no longer be in the study.

I didn’t mind. I had other things going on in my life, like the beginning of high school, cross-country practice and crushes. But I had also learned enough about neuroscience to become consumed by the topic. When I was 17 and entering my senior year in high school, I wrote to Nass and asked if I could do an internship in her lab. She readily agreed.

One day in the lab, I asked if she could show me my study files. We walked into a room filled with stacks of plastic bins, each one brimming with folders and loose papers. She grabbed a folder and read it quietly. Then, peering over a piece of paper, she said, “You were the worst participant because you were perfectly fine! You threw off all of my data.”

Nass, who passed away in 2019, and her colleagues would go on to publish many studies on perinatal strokes. In a 2012 paper, for example, they found that babies suffering these strokes had a higher risk of attention and behavioral problems compared with the general pediatric population. Many of these children — recruited from 1983 to 2006 from Southern California and New York City — suffered from seizures and muscle weakness on one side of their bodies. Most also had damaged or missing areas, known as lesions, in their left hemispheres, like me. I assume that one of those data points was mine.

I went to college and majored in neuroscience. After graduating in 2015, I spent two years working in a lab studying concussions. I spent hours in the magnetic resonance imaging room, watching as other peoples’ brains appeared before me on a computer screen.

But I never thought much about my own brain until this spring, when I happened upon a story in Wired magazine (see https://childnervoussystem.blogspot.com/2022/09/perinatal-stroke-2.html) about a woman just like me: astonishingly normal, apart from a missing temporal lobe.

A Critical Hemisphere

For more than a century, the left hemisphere of the brain has been considered the center of language production and comprehension.

This idea was first proposed in 1836 by Dr. Marc Dax, a physician who observed that patients who had injuries to the left side of their brains could no longer speak properly. Twenty-five years later, Dr. Pierre Paul Broca observed a young man who had lost the ability to speak and could utter only one syllable: “Tan.” A brain biopsy following the patient’s death revealed a large lesion in the frontal part of the left hemisphere, now known as Broca’s area.

In the early 1870s, Dr. Carl Wernicke, a neurologist, saw several patients who could speak fluently, but their utterances made little sense. One of these patients had a stroke in the back of her left temporal lobe, and Wernicke concluded that this section of the brain — now called Wernicke’s area — must serve as a second center for language, alongside Broca’s area.

Modern brain imaging studies have further expanded our understanding of language. Much of this work has shown that two brain regions — the left sides of the temporal and frontal lobes — activate when a person is reading or hearing words. Some researchers have called this the “language network.”

But other neuroscientists have argued that language processing is even broader and not confined to specific brain regions.

“I believe that language in the brain is distributed throughout the entire brain,” said Jeremy Skipper, the head of the Language, Action and Brain Lab at University College London (and my former college psychology professor).

Studies have shown that written words can activate the part of the brain associated with the word’s meaning. For example, the word “telephone” activates an area related to hearing, “kick” triggers a region involved in moving the legs, and “garlic” activates a part that processes smells.

The areas of the brain traditionally attributed to language have lots of other functions, Skipper said. “It just depends on what other sections of the brain they are talking to and at what time and in what context.”

Eight Interesting Brains

The Wired article described an anonymous woman from Connecticut who had no idea she lacked a left temporal lobe until undergoing an unrelated brain scan as an adult. For the past few years, the article explained, she had been part of a research project led by Evelina Fedorenko, a cognitive neuroscientist at the Massachusetts Institute of Technology.

In April, I wrote Fedorenko an email telling her about my missing left temporal lobe and offering to be part of her research. She replied 4 1/2 hours later, and soon I was booking an airplane ticket from my home in rural Colorado to Boston.

There are currently eight participants, including me, in Fedorenko’s Interesting Brain Project, she told me. I haven’t met them, but four of us had presumed perinatal strokes, resulting in damage to our left hemispheres. Two participants have benign cysts in their right or left hemispheres, one had a stroke in the right hemisphere, and one had brain tissue removed from the left hemisphere because of a tumor.

“The brain has incredible neuroplasticity,” said Hope Kean, a graduate student in Fedorenko’s lab who is running the Interesting Brain study as part of her dissertation.

It seems that networks in the brain arrange in a particular way, but if you lose crucial brain regions as a baby — when the brain is still very plastic — these networks can reroute, Kean said.

I arrived at Fedorenko’s lab in Cambridge on a hot day in July. I lay on a bed that slid into the MRI machine’s narrow tube, with a cagelike device placed over my head. Kean snapped a mirror onto the headpiece so I could see a screen at the back of the scanner. As the machine started to make its banging, booming sounds, I remembered all of the times I had dozed off inside as a kid, lulled to sleep by its thundering chords.

On the screen, words flashed quickly and a voice read them aloud, forming random sentences like, “Just the barest suggestion of a heel is found on teenage pumps.” Then, the words switched to a haphazard assortment of letters, creating incomprehensible sounds.

After the scan was completed, the researchers and I crowded around a computer screen, where I saw a slice of my brain for the first time. I stared in disbelief, stunned that my neuronal wiring could have rerouted around this large, oblong hole where my temporal lobe should have been in the space behind my left temple and eye socket.

In a typical person’s brain, the sentences that I heard and read in the scanner would robustly activate the left temporal and frontal lobes, whereas the nonsense sounds would not.

The researchers’ studies found that the brain of the Connecticut patient had adapted by switching sides: For her, these sentences activated the right temporal and frontal lobes, according to a case study published in the journal Neuropsychologia.

My brain, however, surprised everyone, yet again.

A preliminary analysis of the scans showed that, even without a left temporal lobe, I still process sentences using my left hemisphere.

“I had thought that any large left hemisphere early lesion leads to the migration of the language system to the right hemisphere!” Fedorenko said. “But science is cool this way. Surprises often mean cool discoveries.”

A possible reason behind this discovery, according to Fedorenko, is that my lesion is primarily in the front of my left hemisphere, leaving enough healthy tissue in the back for the language system to take root.

Over the next few years, I’ll be flying back to the lab for additional scans and tests, and Fedorenko hopes to recruit even more people with unusual brains to participate in this study.

I still think about the study I was in as a young child and about all of the other kids whose perinatal strokes had left many of them severely disabled. For some mysterious reason, my brain evolved around its missing lobe, whereas theirs struggled to do so. Why wasn’t I born with the developmental and cognitive problems, and they were? Why did my left side rewire to give me the syllables, words and phrases that have so enriched my life?

It’s these questions that make me grateful to have been involved in this study — and to be a research participant once again.

https://news.yahoo.com/curious-hole-head-151127600.html

https://www.nytimes.com/2022/09/04/science/brain-language-research.html