It took more than two decades before a woman learned she had been living without an entire component of a vital organ: the cerebellum in her brain.
The 24-year-old patient went to the Chinese PLA General Hospital of Jinan Military Command complaining of unexplained vomiting and nausea that she experienced for a month. She added that she suffered from dizziness and a hard time walking stably for more than 20 years.
This woman is married and had a successful pregnancy of her own. Though she stood and walked by herself at later ages than most children and had unintelligible speech until she was 6 years old, she was considered to have "mild mental impairment and medium motor deficits," the case study about the woman published in the journal Brain said.
It wasn't until she was in the hospital that doctors found she was missing her entire cerebellum.
Given the extent of her condition, the doctors wrote that her symptoms were "less than would be expected in [complete] absence of the cerebellum."
The cerebellum is a part of the brain involved with coordinating smooth body movements. According to the National Institutes of Health, people who have strokes affecting their cerebellum experience dizziness, nausea and other problems. New Scientist reported that the cerebellum accounts for just 10 percent of the brain's volume but holds 50 percent of its neurons.
The authors of this case study describe the woman's condition — known as cerebellar agenesis — as "extremely rare." The cause of such a condition is unknown.
"There are very few reported cases of complete cerebellar agenesis, making it challenging and controversial to understand the degree of cerebellum development necessary to avoid deficits in motor and non-motor functions," the study authors wrote. "Further, a detailed description of neurological findings in a living adult with cerebellar agenesis is almost non-existent; most cases are reported based on autopsy reports."
Because studying the disease in a living person is so rare, researchers were particularly excited about this case because it could help them answer several questions: "Is normal cerebellar function possible in the case of total or subtotal cerebellum damage? If one part of the cerebellum is damaged, can another part take over?"
The doctors in this woman's case believe that other parts of her brain took over some of the function of her missing cerebellum.
"These rare cases are interesting to understand how the brain circuitry works and compensates for missing parts," Mario Manto, a scientist at Free University of Brussels, told New Scientist.
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