My brief, upside-down career as a guinea pig

My brief, upside-down career as a guinea pig

Skeptical of a professor's hypothesis, the author tested his own by experimenting on himself.

By John F. Stamler, MD
Ophthalmologist/Iowa City, IA

We admire those pioneering physicians who used their own bodies to test new treatments—those John Hunters, William Halsteds, and Werner Forssmanns of medical research, who courageously risked their individual health to serve the health of humanity.

My own foray into self-experimentation wasn't nearly so high-minded, but it sure taught me a lesson.

Maybe I was just reacting to the pomposity of the old professor I encountered during my ENT rotation in medical school. One day, he emphatically stated that the caloric (Barany's) test works because cold water stimulates the cilia of the labyrinth by inducing the circulation of the endolymph. This circulation, he said, mimics the motion of the endo- lymph caused by head motion, thus stimulating the neural reflex arc to the extraocular muscles and producing nystagmus.

As an explanation for why squirting ice water in your ear makes your eyeballs wiggle, I found the old geezer's hypothesis lacking. My own hypothesis was that the cold water reduced the temperature of the vestibular apparatus and nerve, reducing the basal discharge rate and mimicking the effect of moving endolymph.

And I knew just how to prove it. If the circulation of endolymph was involved, gravity would affect the direction of the nystagmus. But if the water just cooled the nerve, it wouldn't. Simple! I could show up that dogmatic so-and-so by merely checking the direction of my nystagmus after performing the procedure while standing on my head.

I was confident of the results. I envisioned myself demonstrating the test before an audience, perhaps at ENT grand rounds. I would earn the admiration of my colleagues and the faculty, change the way the nystagmus test was taught, and perhaps even publish the experiment's results.

Nevertheless, I felt that the test should first be attempted in the absence of public scrutiny. So, alone in my bedroom one quiet afternoon when my wife was away, I gathered the necessary equipment: a bowl of ice water and a turkey baster. I knew that cold should produce nystagmus opposite the ear that it was squirted in. If my hypothesis was correct, my eyes would jerk in that direction whether I was upright or upside down.

I lay prone on the bed, my torso hanging over the edge of the mattress, my head resting on a folded towel that would keep the carpet dry. I chose a jumbo dust bunny beneath the bed as my fixed reference point and slowly lifted the turkey baster to my ear. Gently, I squeezed the bulb. I tensed in anticipation, but despite the chill I felt in my ear canal, the dust bunny did not move.

Not enough ice water, I figured. The next basterful was a vigorous gush that filled my ear and chilled the entire side of my head with overflow. My scalp was going numb when I sensed movement. Concentrating intensely, I fixed my attention on whether the fast movement was to the left or right.

Then the house was suddenly sucked up into a tornado.

The walls spun. The bed flew out from under me. I found myself sprawled on the whirling floor, clutching the carpet to keep from being flung about the room. I tried to stand, but staggered into a wall. I grabbed desperately at its surface before tumbling to the floor.

I was riding a turbocharged merry-go-round with no brakes. With great effort, I tucked and rolled into a sitting position and looked down at the vomitus in my lap, wondering why centrifugal force didn't fling it onto the walls of the spinning house.

Eventually, as I sat with my head between my knees, the room's motion slowed. The walls and floor coasted to a stop, and my panic began to subside. I took a deep breath of relief.

Then the room started turning again, quickly picking up speed. Soon the world was spinning violently, this time in the other direction. I knew what I had to do: I had to get upside down again. I couldn't climb onto the bed, but after two or three tries I managed to get to my hands and knees. I placed the top of my head on the floor again and waited.

The room slowed and then stopped. When it began to re-verse direction again, I found that by raising and lowering my head, I could keep the room fairly steady until my ear finally warmed.

My experiment suggested that the traditional explanation of the cold caloric test was probably correct. The results also demonstrated that gravity did indeed influence nystagmus.

However, I had no desire to demonstrate that fact to my professor. Nor, since that day, have I felt any desire to squirt ice water in my ear.

John Stamler. My brief, upside-down career as a guinea pig.

Medical Economics

2000;8:71.