Although it is not unheard of to
have part of your brain missing, either congenitally or from surgery, the woman joins an elite club of just nine people who are known to have lived without their entire cerebellum.
A detailed description of how the disorder affects a living adult is almost non-existent, say doctors from the Chinese hospital, because most people with the condition die at a young age and the problem is only discovered on autopsy (
Brain,
doi.org/vh7).
The cerebellum's main job is to control voluntary movements and balance, and it is also thought to be involved in our ability to learn specific motor actions and speak. Problems in the cerebellum can lead to severe mental impairment, movement disorders, epilepsy or a potentially fatal build-up of fluid in the brain. However, in this woman, the missing cerebellum resulted in only mild to moderate motor deficiency, and mild speech problems such as slightly slurred pronunciation.
Her doctors describe these effects as "
less than would be expected", and say her case highlights the remarkable plasticity of the brain.
"These rare cases are interesting to understand how the brain circuitry works and compensates for missing parts," says
Mario Manto, who researches cerebellar disorders at the Free University of Brussels in Belgium. The patient's doctors suggest that normal cerebellar function may have been taken over by the cortex – brain scans should reveal the answer.