Doctors in China were recently confounded by a 24-year-old woman who presented in an emergency room complaining of nausea and dizziness but, in fact, was missing a major part of her brain, the cerebellum. The cerebellum, also known as the “Little Brain” represents about a tenth of the brain’s volume but contains more than half of its neurons. It coordinates fluid movement and balance. The cerebellum is also associated with memory, emotions and learning.
The young woman, a married mother of one, had apparently suffered the effects of a condition called, “complete primary cerebellar agenesis.” Her mother reported that she was not able to walk until around seven years of age. Doctors noted slight issues with her speech and the woman reported that she had had trouble with her balance all of her life. While she is only one of nine adults ever diagnosed with this condition, her symptoms are significantly less severe than those of others with the same condition.
Doctors, confounded by the ability of the young woman to live a somewhat normal life despite the absence of the cerebellum, a vital part of her brain, are calling the case a testament to the brain’s plasticity. The first case of this rare condition was reported in 1831 but it was a 1940 report by J.D. Boyd that stirred some debate. During the dissection of the unclaimed body of a 76-year-old man who died from heart disease, students discovered that the man had no cerebellum. Boyd was able to piece together a comprehensive medical history that seemed to infer that the man had lived a normal life.
In 1994, however, Mitchell Glickson set out to explore what he termed, “The myth,” that a person lacking a cerebellum could experience a symptom free life. He argued that there was not enough information available regarding the man’s life, his work or his condition for Boyd’s findings to go unchallenged. Ironically, it was Boyd’s son, Richard, who unearthed his father’s records and wrote an updated reported which cited a number of problems associated with the man’s missing cerebellum. It appeared that the man had difficulty with his speech and problems walking.
Doctors got another chance to study this condition in 2003 when a 59-year-old woman presented with hearing difficulties. A magnetic Resonance Imaging Test (MRI) revealed that the woman was also missing this significant portion of her brain. In this case, however, the symptoms were more pronounced. She also had difficulty with motor dexterity and an uneven gait. She was unable to read or write and her speech was also slurred. This woman experienced some difficulty with hand eye coordination and had also failed to grasp conditioned blinking of the eye. In other words, in the absence of the cerebellum, her brain did not send the proper signal for the eye to blink.
The data garnered from studying this last patient seemed to support Glickson’s myth busting initiative. It did appear at that point, that it was impossible for a person to live a relatively normal life sans an intact cerebellum. The recent discovery of this young woman who has lived her whole 24 years with only moderate symptoms will give doctors much more to consider. While the young woman’s ability to thrive as she has given the fact that she is missing her cerebellum may confound doctors, it also opens the door to further exciting studies about the amazing human brain.
By Constance Spruill