Unable to Create Mental Maps
A year before meeting Sharon, the cognitive neuroscientist, working at the University of Calgary in Canada, had just published the first case study of this “direction dyslexia,” which he named DTD. It came about after a patient came to the university’s neuropsychology department. "She was something exceptional," Professor Iaria explained. "She didn't have any brain damage; she didn't have any neurological conditions or anything else other than getting lost in extremely familiar surroundings." Since he published the woman’s case study back in 2008, he’s sought out other people with the condition and explains what he’s learned. “People with DTD come from all sorts of careers – they are lawyers, teachers, cleaners and writers. They live perfectly ordinary lives and often have no discernible memory or attention issues. “The problem is that they have an absolute inability to create mental maps of their environment, something most people do without even thinking about it. “When you move around, you do so by monitoring a lot of information, you look at landmarks and you try not to bump into walls. There is all this processing of dynamic information. You use this to form and constantly update a cognitive map of where everything is around you. “Normally, people can recreate a pictorial representation of their route in their mind but people with DTD don’t have this ability.”Brain Regions Lack Synchronization
In DTD, several regions of the brain that play a major role in spatial orientation, such as the hippocampus and prefrontal cortex, are working well on their own but are not integrated with each other. Thanks to advances in MRI technology, signals going back and forth can now be tracked and, in those with DTD, are visibly impaired. While DTD is an extreme example of this lack of connectivity between brain regions, each of us has differing levels of connectivity within our brains. Those folks with higher levels of connectivity have better navigation skills when tested with spatial orientation tasks using virtual reality. “The more the network is integrated, the more robust the connections are, the more synchronized these regions are, the better the behavior is,” the neuroscientist said. A recently published decade-long study by Professor Iaria and his colleague Ford Burles compared 1,211 cases of DTD with 1,624 healthy controls. This research confirmed that people with DTD share three similarities:- They get lost in extremely familiar surroundings.
- Their directional disorientation begins in childhood.
- They have no other cognitive issues and report no brain injuries or neurological disorders.
