When Sharon turned 40 she decided to see another doctor. But as soon as she sat down, she felt uncomfortable. “She looked at me like I was telling her a made-up story. She asked me how I correct it and I told her I spin around and it fixes it. She said, ‘Let me see you do it.’” Sharon had never spun in front of anyone before. She winces at the memory. “I swallowed my pride, stood up and closed my eyes. I spun around in circles until I knew the world had flipped.”
The doctor asked Sharon what she saw. “I said, ‘Well, I’m in a different room now. I know logically I’m not, but this doesn’t look like the same room.’”
Sharon spun around again and sat back down. The doctor put down her pen and pad and said: “Has anyone ever suggested the possibility that you have a multiple personality disorder?” Sharon was mortified. “I felt like I was being told I was crazy again. I just couldn’t go through that again. I left.”
It was another decade before Sharon made a further attempt to understand what was wrong with her brain. A friend had read some books by the neurologist Oliver Sacks and recommended that Sharon write to him. Sacks replied, apologising that he had not heard of such a condition. But he said the problem might be similar to another condition called prosopagnosia, in which people are unable to recognise familiar faces.
Sharon Googled “prosopagnosia” and found a website that tested how good you are at recognising faces. After the test, there was a questionnaire. One of the questions hit a nerve: “Have you ever been in an environment that you know you should recognise but doesn’t look familiar?”
“I was like, ‘Holy shit!’” says Sharon, who wrote everything about her condition in the notes section. “Within a week, I received a call from Brad Duchaine, a researcher at University College London.” Duchaine had created the online test. “He was so sweet,” says Sharon. “He believed everything I said, and assured me that at some point there would be someone doing research on my problem.”
Two years later, in 2008, Duchaine emailed her, saying he had good news. There was an Italian researcher moving to Vancouver to start researching the condition she had described. That man was Giuseppe Iaria.
“The first time Giuseppe called, I told him everything. He was such a gentle man. He nearly cried when I told him about the witch thing.”
Iaria told Sharon that he thought there might be a problem with the way in which the different navigational cells in her brain communicate with each other. Over the next five years, he began to test this theory.
He started by scanning the brains of healthy people, looking at how different brain regions known to be important for orientation and navigation communicate with each other. His team concluded that the best navigators were those with higher levels of communication.
This concept is called network theory and it’s an idea that underlies many human behaviours – that the connections between different regions of the brain may be more important than how well the regions function by themselves. It’s like having a quartet of the world’s best brass players who individually make wonderful sounds. But if they’re not playing in time with one another, that music turns into mayhem.
Iaria’s team then scanned the brains of a group of people with Sharon’s disorder. They noted a difference in the activity of their right hippocampus, an area involved in memory, and parts of their frontal cortex, an area that allows us to draw all the information about navigation together. It’s also an area involved in reasoning and general intelligence.
As Iaria’s patients had no problem with their memory, or reasoning, he concluded that the condition must be a result of ineffective communication between the two regions. “It’s not enough for the individual parts of the brain to be able to speak,” he tells me. “They have to have good conversational abilities, too.”
Since then, Iaria’s team has discovered that, just like Claire’s, Sharon’s brain looks anatomically normal; but several of the areas involved in navigation don’t communicate properly. Still, how could Sharon sometimes navigate perfectly well and then suddenly flip?
“Some people don’t actually lack the skill of forming a mental map,” Iaria explains, “but somewhere in the process of collecting all the pieces of the puzzle, errors accumulate, information gets lost, and suddenly the map shifts.”
To Iaria’s knowledge, Sharon’s spinning technique is unique. “I have to admit I have no idea why it works,” he says. “There’s nothing wrong with her vestibular system – she doesn’t get nauseous or have problems with her balance – but somehow shaking this system resets her mental map.” He sighs. “I can scan her brain, but I can’t enter her mind.”
Recently, Iaria has been testing his theory that developmental topographical disorientation has a genetic link. Of all the people he has identified with the condition – almost 200 of them – about 30% have at least one other family member affected. His team identified a handful of potential genes that might be causing the problem. While it’s unlikely that they will be able to replace the broken genes any time soon, it might be possible to intervene – using brain-training exercises that help children with these genes use other parts of their brain to navigate.
I ask Sharon whether her daughter, son or grandchildren have any signs of the condition. “No, thank goodness – they are all really good at navigating,” she says. Did Sharon’s condition appear spontaneously, I wonder, or might it have been inherited?
“My mum?” Sharon guesses. “Yes, I think she must have had it. Looking back, it all makes sense. She never told my dad about my condition, probably because she’d never told him about hers. She never walked us to school or picked us up from anywhere, unless there were other people with us. She never went anywhere by herself.”
Knowing there are people out there trying to understand her condition has helped. “I’ve always been silly and funny because it misdirected people away from the things I was hiding. Everyone said, ‘You’re always in such a good mood.’ They didn’t know that I would go home at night and cry. Before meeting Giuseppe, I was still a scared little girl. I don’t think I grew up and became a woman until the last 10 years, really. I’m happy now. I realised that in order to be fulfilled I needed to learn to like myself and accept who I am.”
As I leave, I catch another glimpse of her lobster lawn ornament. “I know he’s awful,” says Sharon, as she walks me to my car, “but I call him Louie.” She looks back at the house. “If I’m lost and I see Louie, I know I’m home.”
- Some names have been changed. Sharon asked that we did not use her surname.
This is an edited extract from Unthinkable: An Extraordinary Journey Through the World’s Strangest Brains, by Helen Thomson, published on 22 February by John Murray at £20. To order a copy for £17, go to bookshop.theguardian.com or call 0330 333 6846.
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