We’ve met some people who you might describe as brainless, but you never thought that was literally possible—until now. A Chinese woman who walked into the PLA General Hospital of Jinan Military Area Command complaining that she was nauseous and dizzy was recently diagnosed with an unusual condition: the complete lack of a cerebellum.
The cerebellum is pretty damn important when it comes to maintaining a functioning brain, as well as the body as a whole. It governs motor control, particularly when it comes to sensory input and balance, as well as one’s ability to focus, understand and speak language, and feel pleasure and fear. The cerebellum isn’t particularly big—it takes up about 10% of the brain’s space, but it contains dense stores of tissue, as well as 50% of the total neurons.
In the entirety of documented human medical history, only nine people have lived without their cerebellums. In fact, it’s unclear exactly what the consequences of not having one are, given that so few people have lived with such a condition. When someone’s cerebellum is damaged, he or she suffers mental impairment, difficulties moving, and potentially epilepsy
or hydrocephaly. The Chinese woman had fairly mild symptoms, such as some difficulty pronouncing words and slurred speech, and some difficulties with motor functioning, particularly with walking steadily. Certainly her dizziness was a result of her condition, but it’s incredible that there weren’t more effects. She didn’t learn to walk until she was roughly 7 years old, and speech was difficult for her until about the age of 6, but she was still able to reach those milestones.
Doctors attribute her ability to function to the brain’s plasticity and its ability to compensate for parts that aren’t working well—or that don’t exist. Doctors speculate that her cortex may have assumed the functions of her cerebellum, but they won’t know for sure until they conduct further brain scans. Since the woman was born without a cerebellum, other parts of her brain have had an entire lifetime to figure out how to fill the gaps, which makes her distinct from people who undergo a traumatic brain injury at some point in their lives.
Still, the fact that someone can live and function without such an essential part of the brain sheds some light on the brain’s remarkable potential, as well as future medical treatments.