Why researchers are analyzing the brains of London cabbies to help dementia diagnosis

TORONTO -

In London, England, cab drivers have to go through a gruelling test called the Knowledge to become experts on the city’s tangle of roads without a GPS. Now, researchers are studying their unique brains to see if these cabbies can help shed light on understanding dementia.

It’s called the Taxi Brains project, and it’s being run by researchers at University College London.

“We knew that in Alzheimer’s disease, a key part of the brain [that] degenerates is the hippocampus,” Hugo Spiers, professor of cognitive neuroscience and principal investigator in the research, told CTVNews.ca in an email. “London Taxi drivers have previously been found to show an increase in the size of their posterior hippocampus over many decades of driving taxi.

“Because the increased size has been linked to years of driving/navigating or to the training to become a [taxi] driver, the evidence suggests all that spatial knowledge memorization and use leads to a change in the structure of the hippocampus.”

Previous studies have shown that learning the Knowledge of London leads to improvements in the brain, he explained.

Scientists believe if they can understand the mechanisms behind a stronger hippocampus and how it connects to spatial memory, it may help scientists figure out better ways to detect Alzheimer’s and dementia earlier on in the process, which is essential to limiting the spread of the disease and providing better quality of life for patients. The hippocampus is associated with learning and memory, two functions that start to slip as dementia takes hold.

So what is the Knowledge of London? It’s a requirement for driving a taxi in London, and involves spending up to four years studying hundreds of routes and landmarks in the city.

“The London cabbies are required to know the street layout and use it to plan routes,” Spiers said. “It was set up historically in the 1800s and there has been no plan to change it despite the access to GPS for years. The U.K. loves its traditions!”

London has more than 58,000 streets in total, and 26,000 are within the six-mile radius of London’s centre point, Charing Cross. Being able to hold a map of the region in one’s head and plan a route no matter where you are is quite a feat.

While other cities allow taxi drivers to utilize GPS and programs that plan a route automatically, London cab drivers are always using their memory to make their way through the city, and that distinction makes their brains unique.

Researchers have been recruiting London cab drivers to come in and get their brain scanned in a one-hour MRI session. Participants are compensated and also given a questionnaire to fill out at home to test their comprehension and retention of the London streets.

Around 30 cab drivers have participated so far.

Part of the research involves testing a potential diagnostic tool with the cab drivers in order to establish the “upper bounds of navigation ability” and help to improve the tool.

“Research on Alzheimer’s disease and broader dementias is woefully underfunded, and we need more studies to understand the risk factors and life-style choices that relate to the onset of these conditions,” Spiers said.

“This work will hopefully provide a better understanding of a group of people for whom the brain regions involved in orientation and memory are enhanced with experience. They are a rare group of experts and we need to know more about what their brains can tell us, as it might give clues to [tackling] dementia.”

Spiers said they are hoping to have results sometime next summer.

“It depends how much work is required to get the data to give up its secrets,” he said.

He added that they are still recruiting cab drivers, and that anyone who is interested can get in contact with them through the project’s website.