Researchers have reported the case of a boy whose brain was able to rewire after a severe stroke that damaged much of his brain.
In the seventh grade, 13-year old Daniel Carr amazed his baseball coach with his ability to throw with his left hand, saying that it was the fastest he’d ever seen. However, he was unable to properly catch with his right hand.
Hearing this from the coach, Kellie Carr, Daniel’s mother, realised that his son had a number of quirks, such as favouring his left side when he was an infant, and his left-handedness emerged well before the normal age of two or three. However, she was unable to get any explanation for this until she met Nico Dosenbach, MD, PhD, who informed her that her son had had a stroke when he was a newborn.
MRI scans revealed large, bilateral voids in Daniel’s brain, but incredibly, he had no cognitive, behavioural or motor problems other than a lack of strength and dexterity in his right arm.
“The extent of Daniel’s injuries may be on the edge of what’s compatible with life,” Dosenbach said.
Dainel’s remarkable recovery can be explained by his young age at the time the stroke.
“The brain can compensate more quickly and completely for strokes sustained in early childhood,” he said. “By contrast, large strokes in adults often cause death or severe functional impairment with little chance of recovery. However, the mechanics behind this are only beginning to be understood.”
More MRI scans were done on Daniel’s brain to determine its structure and pathology. Dosenbach and Laumann conducted high-resolution functional MRI scans to understand how Daniel’s brain had reorganised itself.
With his mother’s consent, Daniel was further tested over a period of six years, including batteries of neurological tests, and more scans done. Timothy Laumann, MD, PhD, now a fourth-year psychiatry resident at Barnes-Jewish Hospital, had the expertise to analyse the data.
Looking at his medical records, the physician-scientists noted that he had an infection as a newborn, and was hospitalised with an IV drip. However, none of the physicians had suspected a stroke, which happens to one in every 4000 newborns. Daniel was sent home after a week, the doctors having suspected a viral infection.
“The risk of having a pediatric stroke greatly increases with a medical problem, especially an infection during the newborn period,” Dosenbach said. “However, usually there are more obvious signs that a stroke occurred. I can understand how no one suspected it.”
The researchers compared the images of Daniel’s brain to others of young adults, as well as Dosenbach’s own brain, which he had imaged and studied extensively.
“Part of Daniel’s brain structure is gone,” Laumann explained, referring to their analysis of the MRI data. “He’s missing almost a quarter of his cortex.”
The dead tissue was replaced by pockets of cerebrospinal fluid, which acts as a shock absorber, as well as delivering nutrients and removing waste. The surviving neurons formed interconnected islands that restored cognitive and motor functions, and neighbourhoods of healthy tissue were again reconnected.
“Our findings illustrate the brain’s tenacity at reorganizing and recovering functions damaged by a massive stroke affecting both sides of his brain,” Dosenbach said. “Future studies of functional remapping relative to tissue loss may provide additional insights. Our results raise the possibility that variability in outcomes may depend on specific features unique to an individual’s brain.”
Despite the extensive damage, Daniel completed tertiary education and now works as a diesel mechanic.
“His stroke still shocks me,” Kellie Carr said. “How could I have not known? But looking back, maybe it was better that way. I might have babied Daniel and been afraid to let him be a regular kid. Maybe the best thing for him was living normally.”
Daniel agreed: “I think about my right hand daily because I have to constantly think five steps ahead to figure out how to compensate for not being able to use it properly, like I did with the baseball glove. But the last thing I want is for people to act like something is wrong with me. I’m fine.”
Source: Medical Xpress
Journal information: Timothy O Laumann et al. Brain network reorganisation in an adolescent after bilateral perinatal strokes, The Lancet Neurology (2021). DOI: 10.1016/S1474-4422(21)00062-4
