Ballet dancers’ brains adapt to stop them going dizzy

Years of training in “spotting”, the technique of quickly and repeatedly bringing your gaze to two specific points in front and behind you, certainly helps, but new research suggests that the brain’s ability to adapt plays a powerful role.

If you’ve ever tried spinning in circles while looking up to the sky, you’ll know the accompanying dizziness that can follow. But what stops ballet dancers, who pirouette endlessly for a living, from falling into each other like a set of dominoes?

Years of training in “spotting”, the technique of quickly and repeatedly bringing your gaze to two specific points in front and behind you, certainly helps, but new research suggests that the brain’s ability to adapt plays a powerful role. And it could help better treat and diagnose people who suffer from chronic dizziness.

Neuroscientists at Imperial College London recruited 29 female ballet dancers and spun them around in a chair in a dark room. When the chair was stopped, the dancers were asked to turn a lever to indicate how quickly they still felt they were spinning. This measured their perception response to dizziness. Eye reflexes – the quick flicking of the eyes from moving around rapidly – were also measured. In normal people, these two responses correlate well, but in the dancers there appeared to be an uncoupling: while their eye reflexes kept going, their perception response fell.

A group of 20 female rowers, who were similar in age and fitness, were also recruited as a control group. Brain scans were then taken to analyse the brain structures of all the individuals.

Powerful resistance

In cases of chronic dizziness, tests are usually taken of the vestibular organs in the inner ear. These fluid-filled organs use tiny hairs to sense the movement of the fluid, which in turn send signals to the brain. The continued movement of fluid explains one of the reasons you can continue to feel dizzy after you’ve stopped moving. But this doesn’t go far enough to explain dizziness in chronic suffers, said Barry Seemungal, co-author of the study, published in Cerebral Cortex.

“We measured sensation perception and eye reflexes and found dancers were much more resistant to non-dancers,” he said. “In the rowers, sensation correlated very well to reflexes, but in dancers the two were not correlated – they had de-coupled. In a person with chronic dizziness, the duration of their perceptual response is much longer; there’s a disproportionately higher reaction compared to a dancer who shows powerful resistance.”

An MRI scan then looked at the amount of grey matter (the bit that calculates) and the white matter (the part of the brain that makes connections) in the cerebellum. This also threw up differences between dancers and non-dancers.

“A statistical comparison between brain structures showed that in dancers an area of the cerebellum was smaller than in the rowers. This part of the brain also known to be involved in processing signals from the ear. And the more experienced the dancer, the smaller it is. The cerebellum can process signals that are then sent to areas of the brain linked to perception. In dancers it reduces the flow of signals – it acts like a gate.”

The researchers then looked at the cerebral cortex, which is associated in perception, and found stronger white matter in the control group. “More white matter means you’re more likely to be dizzy – in dancers we didn’t see it,” Seemungal said.

Seeing is believing

So how can these findings help people with chronic dizziness? For a start, we now have recognition that the brain is the organ that controls balance and, crucially, that it’s able to adapt.

“Traditional testing considers the ear as the organ of balance,” Seemungal said. “I’m a neurologist so I consider it as the brain.”

“The brain takes in lots of different information to make an assessment and compensates if it needs to. The ear is one source, vision is another. If you hear a noise to the right and move your head to look at it, your brain combines the estimates and places greater weight on the more reliable, in this case the eye.”

“But vision can be ambiguous – for example when you’re sat on a train and another one moves and you think you’re the one moving. As a general principle the brain prioritises visual motion over vestibular organs [the ear]. Another example is the ventriloquist’s doll, it combines the auditory and visual inputs but relies more on the visual so you think it’s the doll that’s talking.”

“If your vestibular organs aren’t working well, your brain won’t trust them and even trivial visual stimuli can trigger a dizzy sensation. But traditional testing relies on testing the vestibular organs, which might indicate nothing is wrong.”

People with chronic dizziness can be treated for underlying causes but also longer-term physio treatment. Depending on the form of the condition, this can include exposing them to self-motion (the swaying we all do but don’t notice if we don’t suffer from dizziness) and visual motion to get the brain more habituated.

One lucky find (for the researchers anyway) was that one of the dancers involved in the study later went on to develop chronic dizziness. This enabled the team to test her against their original findings. They found that although her reflex functions had remained the same, her perception response had become stronger.

Professor Nicky Clayton, a Professor of Comparative Cognition at Cambridge and Scientist in Residence at Rambert, the contemporary dance company, said: “As a dancer you learn tricks that allow your body to move in very flamboyant ways but without losing control. One of the tricks I learned was that when you get that sense of spinning, you use your core muscles to pull up; and that you’re disengaging with that feeling of fluidity and creating a stabilising energy.

She added: “Dancers think in very abstract ways … The way in which the brain talks to the cognitive system, whether through its plasticity or psychologically, is more than just spotting. Spotting helps you to focus but it’s not the only thing.”

Simon Lloyd, an ENT specialist, said: “The tests could potentially be useful because at the moment we have no effective way of testing how well parts of the balance system within the brain are working. Testing this would also allow us to measure how people are responding to treatment.”

The Conversation

This article was originally published at The Conversation. Read the original article.

Dancers of Cuba national ballet perform during a rehearsal for Swan Lake in Madrid in 2009. Photo: AFP/Getty Images

Jo Adetunji is the commissioning editor for health and medicine at The Conversation UK.

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The Fall is back - and once again making me weary

Five more episodes to go, after which its “feminist” writer (his word, not mine), Allan Cubitt, should pull the plug on it at last. Plus: Damned.

It is with much weariness that I return to The Fall (Thursdays, 9pm), the creepy drama that still doesn’t know whether it wants to be a horror-fest or a love story. I’ve written in the past about what I regard as its basic misogyny – to sum up, it seems to me to make a fetish of the violence committed against women, a preoccupation it pathetically tries to disguise by dint of its main character being a female detective – and I don’t propose to return to that theme now. However, in its early days, it was at least moderately gripping. Now, though, it appears to be recovering from some kind of nervous breakdown. If in series two the plot was wobbling all over the place, series three has misplaced the idea of drama altogether. Nothing is happening. At all.

To recap: at the end of the last series, Paul Spector, aka the Belfast Strangler (Jamie Dornan), had been shot while in police custody, somewhat improbably by a man who blames him for the demise of his marriage (oh, that Spector were only responsible for breaking up a few relationships). On the plus side for his supposed nemesis, DSI Stella Gibson (Gillian Anderson), before he fell he led them to Rose Stagg, the ex-girlfriend he’d locked in the boot of a car some days previously, and she is going to live. On the minus side, Spector’s injuries are so bad, it’s touch and go whether he’ll survive, and so Gibson may never see him brought to justice. Of course, the word “justice” is something of a red herring here.

The real reason she wants Spector to live is more dubious. As she stared at his body in the ICU, all tubes and monitors, her expression was so obviously sexual – her mouth opened, and stayed that way, as her eyes ran over every part of his body – that I half expected her to reach out and stroke him. Just in time for this nocturnal visit, she’d slipped into another of her slinky silk blouses that look like poured cream. (Moments earlier – think Jackie Kennedy in 1963 – she’d still been covered in her love object’s blood.)

The entire episode took place at the hospital, police procedural having morphed suddenly into Bodies or Cardiac Arrest. Except, this was so much more boring and cliché-bound than those excellent series – and so badly in need of their verisimilitude. When I watch The Fall, I’m all questions. Why doesn’t Stella ever tie her hair back? And why does she always wear high heels, even when trying to apprehend criminals? For how much longer will the presumably cash-strapped Police Service of Northern Ireland allow her to live in a posh hotel? Above all, I find myself thinking: why has this series been so acclaimed? First it was nasty, and then it was only bad. Five more episodes to go, after which its “feminist” writer (his word, not mine), Allan Cubitt, should join Gibson in the ICU, where together they can ceremonially pull the plug on it at last.

Can Jo Brand do for social workers in her new comedy, Damned, what she did a few years ago for geriatric nurses in the brilliant Getting On? I expect she probably can, even though this Channel 4 series (Tuesdays, 10pm), co-written with Morwenna Banks and Will Smith, does have an awfully inky heart. Hungry children, drug-addict parents, a man who can go nowhere without his oxygen tank: all three were present and correct when Rose (Brand) went to visit a client who turned out to be a woman who, long ago, had nicked her (Rose’s) boyfriend. Ha ha? Boohoo, more like.

Damned is basically The Office with added family dysfunction. Al (Alan Davies) is a hen-pecked wimp, Nitin (Himesh Patel) is a snitch, and Nat (Isy Suttie) is the stupidest and most annoying temp in the Western world. This lot have two bosses: Martin (Kevin Eldon), a kindly widower, and Denise (Georgie Glen), the cost-cutting line manager from hell. And Rose has a plonker of an ex-husband, Lee (Nick Hancock). “I’ve been invited to the Cotswolds for the weekend,” he told her, trying to wriggle out of looking after the children. “Is that why you look like a knob?” she replied.

Jerky camerawork, naturalistic acting, a certain daring when it comes to jokes about, say, race: these things are pretty familiar by now, but I like it all the same.

Rachel Cooke trained as a reporter on The Sunday Times. She is now a writer at The Observer. In the 2006 British Press Awards, she was named Interviewer of the Year.

This article first appeared in the 29 September 2016 issue of the New Statesman, May’s new Tories