The results showed that brain networks in the hemispherectomy patients-networks that control walking, talking, and other functions-were remarkably intact. The patients' scans were compared to those of healthy individuals. The research team performed magnetic resonance imaging (MRI) scans on the patients, all of whom received the surgeries as children and now have relatively normal cognitive abilities. In a new study in the journal Cell Reports, neuroscientists at Caltech describe an investigation of six of these rare patients that offers new insights into how human brains adapt to such extreme changes. Remarkably, many of these patients are cured of their seizures and possess basic motor, language, and cognitive skills. Nonetheless, this remains a fascinating neurological case study that showcases the adaptability of the human brain.In the most extreme cases of epilepsy, when a patient's seizures are relentless and do not respond to other treatments, doctors may perform a surgery called a hemispherectomy to remove half of the patient's brain. Somewhat strangely, Brescian and her team don't seem to have performed these kinds of specialized tests with H.W. In such cases, the severance of the brain’s mighty communication cable did have profound consequences but these were only apparent in careful lab tests when researchers presented stimuli to just one hemisphere or the other. However, it’s also notable that the friends and relatives of many split-brain patients - whose callosum’s were cut in adulthood - often reported no obvious effects of the surgery. For example, last year, researchers reported the remarkable case of a boy who recovered his language abilities to near-normal levels after losing almost his entire left hemisphere at age two and a half. H.W.’s story is consistent with the general rule that the brain adapts more readily to congenital or early acquired injuries or abnormalities, than to insults suffered later in life. The main message from the authors of this case study, though, is H.W.’s remarkable high-functioning, and his apparently unaffected life. These issues, especially of motor control, are likely related to his congenital (from birth) condition, but they may also result from age-related neurological changes.
He did display memory problems and also some difficulties with fine motor control, especially when using both hands at once, and drawing. This included IQ tests, abstract reasoning, naming tests, visual scanning, motor planning, visual attention and auditory perception. and on most he excelled or performed normally. said, were new.īrescian and her colleagues conducted comprehensive neuropsych tests on H.W. Until recently, if H.W.'s testimony is to be believed, he appeared to have suffered no significant psychological or neurological effects of his unusual brain. In fact, a detailed clinical interview revealed that he’d led a normal, independent life - first in the military and later as a flower delivery man. Given the importance of the callosum for connecting the bicameral brain, you’d think this would have had profound neuropsychological consequences for H.W. The medical name for H.W.’s rare condition is agenesis of the corpus callosum, meaning that he was born with this structure missing. The main channel between his two brain hemispheres was completely missing. But when the researchers - a team led by Natalie Brescian - scanned H.W.’s brain, they made a surprising discovery. He scored 30 out of 30 on the “mini mental state examination”, which is used to pick up signs of dementia or confusion.
Preliminary tests found him to be high functioning. In many ways, it’s as if the surgery leaves their mind divided in two.Ī new paper reports on an elderly gentleman, referred to as H.W., who aged 88 presented at a clinic complaining of recent intermittent problems controlling his left hand and some mild memory difficulties. People who receive this treatment are referred to colloquially as split-brain patients and lab tests reveal profound effects on their mental functioning. In an increasingly rare procedure, the callosum is sliced as a radical treatment for epilepsy. This is no quiet lane, it’s a major freeway constituting around 200 million neural tracts. The main connection between the two halves is a thick bundle of fibers called the corpus callosum. One of the most distinctive physical features of the human brain is the fact that the cortex is divided into two hemispheres.
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