People with a form of the rare and somewhat mysterious Alice in Wonderland syndrome may one day have better diagnostic and treatment options after scientists mapped a circuit in the brain implemented in the condition.
Named after Lewis Carroll’s eponymous character, Alice in Wonderland syndrome (AIWS) describes people seeing or perceiving their own body parts – as well as those of others, and objects – in distorted proportions, such as being abnormally large.
, almost a century after Carroll wrote Alice’s Adventures in Wonderland, where one chapter describes the character feeling her body grow larger and smaller. Why the condition occurs is unclear, but it can be caused by migraines, epilepsy and inflammation or damage to the brain.
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Some of this damage shows up on magnetic resonance imaging (MRI) brain scans as lesions, which can vary between people. This disparity is partly why Alice in Wonderland syndrome has no set therapy, with medics instead focusing on treating its underlying cause on a case-by-case basis.
To learn more about how the condition affects the brain, at Brigham and Women’s Hospital in Boston, Massachusetts, and his colleagues looked at scans from 37 cases of Alice in Wonderland syndrome, caused by brain lesions, that had previously been described in the medical literature.
Using a technique called lesion network mapping, the researchers compared these brain scans with those of 1000 people without any known neurological condition.
The team found that more than 85 per cent of the lesions causing the syndrome were connected to two brain regions: the right extrastriate body area (EBA) and the left inferior parietal lobe (IPL), both located towards the back of the brain.
The right EBA – part of the occipital lobe, which is responsible for visual perception – becomes activated when someone looks at a body or its parts, while the left IPL is activated when gauging quantities, such as sizes.
Next, to verify that only lesions caused by Alice in Wonderland syndrome, not other conditions, were involved, the researchers analysed the MRI scans of more than 1000 people with lesions related to 25 other neurological conditions. They found that a circuit between the right EBA and the left IPL appears to be exclusive to Alice in Wonderland syndrome.
“This study’s network mapping of AIWS lesions illuminates a promising path toward refining diagnostics and treatments for Alice in Wonderland syndrome,” says at Duality Psychological Services in California. “By identifying the correlated regions in the brain, more precise diagnostic tools can be developed.”
Alice in Wonderland syndrome has no set diagnostic test, with diagnoses usually involving people being asked about their symptoms and medics ruling out other conditions.
Frank notes that the study was small and says the results would have been more accurate if the scans had been presented as three-dimensional to allow for more precise mapping of the brain circuit.
medRxiv
