Saturday, January 16, 2010

Balance Test: Hearing, Tipping, Eye Tracking and Waterboarding

The other day, I went to the Hospital of the University of Pennsylvania for a balance test.  On a side note, I am constantly getting lost there.  Never mind the fact that 25 years ago, I worked at the University of Pennsylvania Medical School and was constantly getting lost during my errands in the hospital  then as I am now.  I guess it is part and parcel of not having a good sense of spatial organization.  There is nothing like wandering the corridors wondering if you are in the right wing.  The place is humongous and I have worn out a lot of shoe leather on its corridors.

Additionally, they have been expanding the place constantly.  Every time a well-to-do alumni with  a spare, say, $100 million to throw around, they seem to toss up a new wing.  No master plan so everything is attached higgledy piggledy, at least, from my point of view.  Additionally, the University of  Pennsylvania is going on a major expansion of medical and engineering facilities behind the Hospital of the University of Pennsylvania to tie the University campus to Center City.  One of the new facilities will be the  Neural and Behavioral Sciences Building so maybe the research there will help us get the smarts to navigate the medical building complexes successfully.  I guess, one test of the success of vision therapy will be my ability to find my doctors successfully.

This time wasn't too bad... I managed to get out of the parking garage, over the bridge and into the Hospital and up to the Fifth Floor of the Silverstein Pavilion.  I check in and they give me a beeper like you get at a restaurant.   Hospitals are running these queueing systems to get everyone through faster and are secretly timing their employees to find out who is holding up the process. 

At any rate, I get called in for my balance test.  I met the audiologist, Carol, who does a basic hearing test in a booth.  She tests the tones and my ability to hear words.  I seem to do OK.  BTW, I've always hated hearing tests in school and I'm none to happy with the number of tests I have to do.  But, I am a compliant patient and I do what I am told as best I can. 

Tipping:  Next is the Posturography Test.  Posturography is a test of balance that assesses the ability to maintain upright posture (standing up right) and proper gait or manner of walking.  There are three separate functions that contribute to the sense of balance: somatosensory, vision, and vestibular. The Somatosensory function is the ability to stand quietly and maintain balance on a flat, unmoving surface. Vision helps to maintain balance when a standing surface is uneven or unreliable. The internal reference for balance is our vestibular system.  Posturography tests which one of these functions is contributing to a sense of imbalance.

I get on the Equitest,  which has a moveable floor and tilting walls. You are strapped in the harness and the floor moves as you move.  So if you are not standing perfectly still, there is some jiggle.    The computer to the left captures the amount of jiggle going on.  Carol, via computer hookup,  moved the walls and jiggled the floors and captures my reactions to this.  Not too bad a test.  It is sort of like sailing so I am used to compensating by fixing my eyes on a point as the world moves around me.  Although, it did get me to the point of dizzyness and the beginning of seasickness.  So I stopped for a minute after we finished.

After that, we used a Rotary Chair which not only rocks back and forth but spins.  It is in a cylindrical room.  Rotational testing determines whether or not dizziness may be due to a disorder of inner ear or brain. 

Carol put a headset on my head so that she could track the eye movements.    There is some sort of infrared eye tracking device in the headset. She set my head in a frame and used some webbing to strap it in place so it couldn't move. She then had me sit in the dark and tracked my eye movements.  Then she had me watch a red dot as it went to the left, right and center at varying speeds.  I also watched stripes on the wall as the chair went in a circle.  We did a variety of other tests as I spun around in the dark.  I can't remember them all.  Oh yeah, she was a little concerned because my eyes kept flitting about in the test. Apparently, it is really important to keep your eyes still.

Eye  Tracking:
The last test was the Infrared Nystagmography. I was in a chair that tilted back into a stretcher.  There was a screen in front of me and Carol put on another headset.  This time I shifted between sitting up right with/without support  and laying down.  All the while, I was watching a green dot moving about as the Carol tracked my eye movements.  For some reason, I wasn't too secure sitting up without holding onto anything.

 Here's what the audiologist sees in my eyes
and there is an other computer screen to control the test.  Below is the headset I was wearing.   Although at the end of test, I wasn't looking as happy as that model is.

   There are four main parts to the infared nystagmography. Eye movement tests are useful, because some patients with balance system problems have problems seeing clearly when moving, or they get the erroneous sense that objects are moving.The calibration test evaluates rapid eye movements. The tracking test evaluates movement of the eyes as they follow a visual target.  The audiologist tests for Occular Motility, that is, following with your eyes objects that jump from place to place or move smoothly.  The audiologist is looking for any slowness or inaccuracies in the ability to follow visual targets.  The positional test measures dizziness associated with positions of the head.  This is a test of  Positional Nystagmus:  as the head and body into various positions to make sure that there are no inappropriate movements of your eyes when your head is in different positions. The caloric test measures responses to warm and cold water circulated through a small, soft tube in the ear canal.   Apparently, it is the gold standard for testing vestibular function. 

So first, we tracked eye movements both in the dark and then as my eyes followed a red dot moving at different speeds, we also moved my head around. 

Finally, the "waterboarding" aka the caloric test.  No, not like Abu Ghraib.  But it wasn't too pleasant, either. Carol didn't pour water over my face or hold me down under water  but she did pour warm water first, in one ear, and then in the other.  To take my mind off things, as the whole procedure is really disorienting and rather nauseating, she had me say names of girls in alphabetical order and then stare at a green light in the headset and then stare at a spot at a ceiling.   The room just spun round and round for a while and then it stopped.   I used some of my sailing experience to get a hold of myself -- so I tried to focus and keep my mind off of things.  For some reason, I started to think about eating candied ginger which I used to do on the boat when I got a little queasy in a storm.   Then, we did the second ear.  For some reason, it was a lot worse experience than the first ear.  She poured the water in and had me say names of boys in alphabetical order.  I couldn't  concentrate and was wildly calling out names and skipping letters as the room spun about.  I just felt like I was whirling out of control.  When the green light came on, I tried like mad to focus on the light because I knew it would make me feel better.  Then the light went off and I could focus on the ceiling.  I was really quite nauseated and dizzy.  I laid there for a few minutes to get a hold of myself.  And then the test was over.

Carol helped me up.  I knew I couldn't leave to drive home right away so I went to the cafeteria and had some sushi and a juice drink.  I felt a bit better so I jumped in my car and started driving home.  I couldn't make it back home so I pulled into a McDonald's and locked the doors and took a nap.  It must have been the funniest thing to see  as my car was still quite covered with road salt from the snow storm we had a few days before my appointment and I was wearing a big fur coat with a hood!   If anyone looked into my salt mine of a car, they would have seen this big fur ball.  Took my nap and then went home and slept for the rest of the day.

I'll see the ENT in March so we will know what the end result of all of this is at that time.  Apparently, the vestibular system ties together a number of different senses:  hearing, vision and balance.  I will blog more on this at a later date.  But, I will get the results forwarded to my developmental opthamologist.  I suspect that she would be interested in the effects of all these tests have on eye function.

If anyone is geeky enough to want to delve into the vestibular system further, go to:

Vestibular Testing

Reblog this post [with Zemanta]