Pouring Cold Water into Your Left Ear Is a Temporary Cure for Insanity
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Pouring Cold Water into Your Left Ear Is a Temporary Cure for Insanity

Caloric vestibular stimulation by irrigating a patient's left ear with cold water has got to be one of the oddest psychotherapies that is actually effective.
November 23, 2015, 2:00pm

As a coping mechanism, denial can be extremely useful. You can delude yourself into thinking you're qualified for your dream job, you're going to lose those last ten pounds, or that AMC will be able to replicate the Breaking Bad success with other franchises. But research in neuroscience has shown that there's actually a way to free people from the irrational clutches of denial, and it's not through the use of expensive treatments or psychotropic drugs. All it takes is a few ounces of cold water.


In the early 1990s, neuroscientists from the University of Milan treated an 84-year old woman, referred to as A.R., who had suffered a stroke in the right hemisphere of her brain. She was alert and sound of mind, with one major caveat: She insisted that her left arm didn't belong to her.

Forty years earlier, Dr. J. Silberpfennig had described "activating" a part of the brain called the vestibular system by irrigating a patient's ear with cold water. Noting the relationship between eye movement and the vestibular system, Silberpfennig used it as a temporary cure for a patient who ignored any information from half of her vision field, as if she were wearing an eyepatch despite having full vision in both eyes. Inspired by Silberpfennig, the University of Milan researchers decided to try activating the vestibular system with A.R.

The procedure, called caloric vestibular stimulation (CVS), is weirdly simple. The external left ear canal is irrigated with ice cold water. The difference in temperature between the water and the body creates a convective current within the fluids in the ear, which stimulates the vestibular nerve, and then part of the brain stem, and then a nerve in the eyes. (See? Super simple.) This sets off a reflex; a series of involuntary eye movements called nystagmus. Nystagmus is an added bonus to the vestibular stimulation—not only does it demonstrate that the vestibular system has been stimulated, but it looks really creepy.

After her ear was irrigated, the patient's mood stabilized and she even expressed embarrassment for her previous manic behaviour

Before vestibular stimulation, A.R. was in total denial about the ownership of her arm, telling researchers that it belonged to her mother and that she had found it in her bed. Immediately after vestibular stimulation, A.R. was asked about her left arm. She admitted it was her own.

This isn't one freaky effect that's limited to people who deny their paralysis; it's a freaky effect that applies to a lot of different people in various mental states. In a study of patients who had phantom limb pain (a condition where a limb is missing but the patient still experiences sensations and often intense pain from the limb), all ten participants reported lessened phantom pain after CVS. One woman with severe bipolar disorder was successfully treated with CVS in the midst of an intense manic episode after antipsychotic drugs and even electroconvulsive therapy had failed. After her ear was irrigated, the patient's mood stabilized and she even expressed embarrassment for her previous manic behaviour.


It's not just extreme cases where CVS shows an effect. Researchers from the UK and Switzerland looked at people with unrealistic optimism, defined as healthy people who underestimated their future misfortunes. After CVS, unrealistic optimism was significantly reduced. Researchers are also looking at the effects of CVS on mood in non-manic individuals (like the situation with the bipolar patient, CVS appears to lower positive mood); verbal skills after a stroke (CVS seems to improve language); and purchase decision making (CVS reduced probability of purchasing a product and desirability of the product).

More recently, researchers are going beyond the initial scope of CVS to do groundbreaking work. Researchers from England and Italy recently published a paper investigating the effects of CVS on pain, showing that CVS can alleviate pain perception and the processing and encoding of pain in the nervous system. "Here, we show, for the first time, that cold left ear CVS reduces the earliest responses to purely nociceptive stimulation," state authors Ferre, Haggard, Bottini and Iannetti.

It would appear that CVS is a magic cure-all, next in line to be touted by Dr. Oz. So should we all constantly be irrigating our left ears with ice water? If we were all under perpetual vestibular stimulation, society would be logical and rational, there would be no religion or capitalism, and basically everything foretold in Lennon's Imagine would come true. However, that may not be totally realistic.


To begin with, the temperature and vertigo that accompanies CVS is extremely uncomfortable. The feeling is comparable to receiving a wet willy outside during a Canadian winter while on a poorly-made roller coaster.

It's also a little unclear how and when CVS actually works.

V.S. Ramachandran, the Neil Armstrong of neuroscience, was one of the first researchers to use CVS with anosognosia (an impaired awareness of an illness or disability, the same disorder A.R. had) just a few years after the University of Milan team used it with A.R.

Known for his innovative theories, Ramachandran had a few different hypotheses for why CVS produces the interesting effect it does. He posited that pouring ice water into the left ear could stimulate the right hemisphere where an "anomaly detector" could be located, or it could cause the brain to reorient itself to this new frame of reference. He also hypothesized that the nystagmus (the creepy eye movements) could be linked to REM sleep and the recovery of repressed memories.

Since then, researchers have had various opinions about whether the effects of CVS are due to a reorientation effect, or because of an interaction between the nystagmus and the vestibular system, or something else entirely. There has also been very little discussion of how CVS could affect a healthy individual. Whether the effect happens thanks to a reorientation effect, an interaction, or even because of repressed memories, doing a factory reset on your brain doesn't seem like it would have an effect if you have no irrational beliefs; it seems to only work if you once held a rational belief, conscious or subconsciously, that is now being clouded by something else. So while it would be satisfying to irrigate the left ear of Ben Carson and interrogate him about creationism, unless he believed it once or currently believes it deep down, it's unlikely his beliefs would change under CVS.

Also, the re-found rationality is temporary. The amount of time it lasts varies from person to person.

For A.R., the awareness of her paralysis and the ownership of her arm only lasted a few hours until the vestibular stimulation wore off. The researchers repeated the stimulation three times. Each time, A.R. confirmed that her left arm belonged to her while under vestibular stimulation. Each time, she went back to the denial after the vestibular stimulation wore off. After the last stimulation, A.R. reasoned with the researchers regarding the situation, now referring to her arm as her son's: "Look, it's queer, but that's how it is. Just fancy finding your son's arm in your bed!"

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