Sep 30 2013

Why Isn’t the Spinning Dancer Dizzy?

This is not a reference to the spinning dancer optical illusion, but rather to real dancers. Why don’t ballet dancers get dizzy when they spin around? Partly this is due to technique – a technique called spotting, in which dancer keep their head in one position for as long as possible then rotate it around quickly back to their fixed position. You have likely noticed this while watching ballet dancers.

But spotting does not entirely explain the ability of experienced dancers to tolerate spinning without becoming vertiginous. A new study finds that brain plasticity is also playing a role – the brains of experienced dancers adapt by reducing the signals that would cause dizziness.

To clarify, the term “dizzy” is a bit non-specific. People use it to mean vertigo (the sense of spinning or movement), but also light-headedness (feeling as if you might pass out), just being off balance, or even for any vague sensation in the head. What is being addressed in this study is vertigo, the feeling you get if you spin around.

Vertigo derives mainly from the vestibular system, the sensory organs of which are in the inner ear. There are canals filled with fluid (endolymph) that will move in response to gravity and acceleration – movement and head position. When you spin around and then stop the fluid continues to flow for a minute or so, creating vertigo.

Sensory input from the vestibular organs is routed through the brainstem and then primarily processed in the cerebellum, the part of the brain responsible for balance and coordination. Vestibular input is processed along with visual input and proprioception (sensation of where your body parts are in three-dimensional space) to create a seamless sensation of where your body is and how it’s moving.

When these sensory streams conflict, that also causes vertigo or motion sickness. That is why you can get motion sick on a moving vehicle. Your visual and vestibular input don’t match. These sensations are ultimately experienced by the cortex.

Chronic spontaneous vertigo is a common problem. Often we do not find a specific cause, in which case there is likely some problem with the processing of the various sensory streams leading to a feeling of vertigo.

This is where the new study might have a potential application. Researchers looked at ballet dancers and rowers of equal physical conditioning. They then looked at their brains in fMRI scanners, and also their reflex eye movements (nystagmus), in response to being spun around. They found that the cerebellar and cortical areas that light up when subjected to spinning were reduced in the ballet dancers compared to the rowers, and this effect was stronger with experience.

The researchers concluded that ballet dancers over years of training suppress input from the vestibular system and the response to that input, so they experience less vertigo when spinning.

This finding is not surprising. For patients who experience chronic vertigo, vestibular therapy is an established and effective treatment ( for both central and peripheral vertigo). It is probably more effective than any medication.

Vestibular therapy consists of exercises that are designed to provoke vertigo to a moderate extent that patients do over and over again to “desensitize” them to the provocation and experience of vertigo. This is essentially the same thing as the plasticity described in the current study.  Of course patient do have to stick with the therapy for months for the benefits to really accumulate. It’s not a quick fix.

This is all one more line of evidence that the brain is a changing organ. It adapts to use, but slowly. It seems that almost any aspect of brain function can be altered with training and use. There are limits, of course, and this effect may not be sufficient to completely compensate for brain disease or damage. There is also no magic shortcut to altering brain function – it takes time and dedication. But it is nice to know that we can alter the neurons in our brain with sufficient effort.

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5 responses so far

5 Responses to “Why Isn’t the Spinning Dancer Dizzy?”

  1. DevoutCatalyston 30 Sep 2013 at 8:34 am

    Can vestibular therapy help older adults ? I’d like to accompany someone on the Tilt-a-Whirl, that old time deceptively tame looking carnival ride that makes many adults want to vomit.

  2. oldmanjenkinson 30 Sep 2013 at 8:51 am

    There is a gentleman in his late 60′s at the gym where I used to go (thank you rotator cuff!) who suffered a cranial injury secondary to a vehicle collision. He has been doing vestibular therapy which he says has helped. He still has to monitor how quickly he turns his head to the left but can turn it at a much more rapid pace without fear of getting dizzy and falling down. It has always amazed me when ice skaters spin. Have any studies looked at this Dr. Novella? I can imagine the velocity they spin in vastly faster than when ballet dancers do it. The Tanoura dance done in Egypt is amazing not just for the spinning but also the colorful skirts done when performed.

  3. The Other John Mcon 30 Sep 2013 at 9:15 am

    Sort of the opposite pattern also occurs, in which the brain seems to adapt to motion but the effect won’t turn off when the motion goes away. This happens sometimes for people after riding planes, trains, and automobiles (but boats seem most common). After returning from a trip, and motion is stopped, people feel like the world is still moving, and for some unfortunate people this effect may never go away. Check out:

    http://en.wikipedia.org/wiki/Mal_de_debarquement

    Does NOT make me want to try a cruise!

  4. Enzoon 30 Sep 2013 at 3:56 pm

    In the martial arts, I’ve encountered this canard that the longer one has practiced, the more likely they are to develop motion sickness in things like cars and amusement park rides. Anecdotally, I’ve heard many times that experienced practitioners feel motion sick in some situations when earlier in their lives they had not.

    Are you aware of any plausibility or truth to this? You’ve made me want to check into it.

  5. DaveLilieon 02 Oct 2013 at 2:21 pm

    This reminds me of training when I was a naval flight officer. As part of our aviation indoctrination courses, we went into a Multi-station Spacial Disorientation Devide (MSDD) or, as we called it, “the spin and puke.”

    http://www.migrationspecialties.com/pdf/MSDD.pdf

    It helped train young pilots and aircrew in spacial disorientation and airsickness physiology and prevention techniques. Some slipped through and had debilitating airsickness when they reached their training or operational squadrons. These unfortunate folks would return to Pensacola for more intense training in the centrifuge to try and overcome the airsickness they developed. A process of making them more sick so they will be less sick.

    An occasional victim of airsickness myself, especially on low altitude, turblent flights with lots of maneuvering and no outside references, I would get airsick if I had not flown for a while. If I were flying several times a week, I would acclimate after just a few days and had problems only during the most extreme of maneuvers. It is miserable trying to complete mission essential tasks when you are throwing up.

    We also see this in our astronauts who have very light schedules during their first few days in space since, as I recall, space sickness affects about 70% of them. But they, too, quickly adjust and become fully funtional and symptom free after just a few days.

    I’m not sure if this is neuroplasticity in action but some acclimation to this type of motion induced vertigo seems more rapid than the months required adjusting to the central or peripheral vertigo discussed in the article above.

    Great stuff, Dr. Novella. I try to read every posting. Keep it up!

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