Thursday, October 22, 2015

Vertigo and ENG

As I have hinted here several times, I have had episodes of dizziness and loss of balance, technically known as vertigo; the last attack was probably triggered by our trip to Venice in May. For a few weeks after that, I had to lie in bed turned on my right side and any attempt to turn to the left would cause immediate vertigo. Fortunately I almost always sleep turned to the right, but the lack of choice was annoying.

After this went on for a few weeks, whilst also suffering in a dramatic increase in headaches and migraines, I went to an Ear, Nose and Throat doctor. After a brief assessment, he ordered some medication, but more importantly ordered three tests: a head CT scan, a hearing test and something called ENG. To my surprise, I was able to have the CT within a few days - the results show no problems. I also had the hearing test within a week or two, which also showed no problems.

The ENG test seems to be popular - or rather, the hospitals allow barely sufficient resources to meet the demand. One Jerusalem hospital offered me an appointment in December, which would have meant a waiting time of about four months. Fortunately, another hospital offered me an appointment in October (only about two and a half months waiting), and this is where I was a few days ago. Although a waiting time of four months is extreme, the technician told me that it is important to perform the test when the subject is not suffering from vertigo. This way, the test can be performed properly without internal attacks interfering with it.

There were three parts to the test, all of which I 'performed' whilst lying on a modified dentist's chair. Electrodes were attached to my skin; these pick up the galvanic response of the muscles around the eyes. It seems that my very dry skin caused problems for the electrodes; at one point, the technician had to replace them and even then, she wasn't sure that they were working well. Does this mean that I will have an advantage when taking a polygraph test (not that I ever have)?

During the first part of the test, I had to look at an electronic board placed about 1.5 metres from me. On this board appeared a red dot, which moved from side to side; I had to track this dot with my eyes without moving my head (this sounds easy but is actually quite difficult). At first, the dot moved smoothly back and forth, but in a later stage, it appeared at a random location on the board. After a few minutes of this, the board was rotated by 90 degrees, thus the dot was moving up and down; this was harder to track. The board was then rotated back by 90 degrees, but the speed of the dot moving from side to side was slowly increased until it was whizzing back and forth. Maybe the technician continues to increase the speed until it becomes obvious that the person being tested cannot track the dot at the increased speed. All of these tests left me with a queasy stomach but with no vertigo.

The second part involved me moving rapidly from a sitting position to a prone position, turned to the right (my preferred sleeping position). I then had to turn to lie on my left side. This was repeated a few times and didn't cause me any apparent vertigo.

The final part was the caloric test, which is divided into four parts. Throughout the entire test, I had my eyes closed (opening the eyes tends to cause vertigo to cease). In the first part, hot water (44 degrees) was introduced into my right ear for a minute or so; this was initially quite painful as the temperature of the water was too hot for comfort. After about 30 seconds, I began to experience vertigo; this is perfectly natural and in fact the purpose of the test is to see whether there is a measurable difference in the induced vertigo, depending on ear. Subjectively, it felt as if I were turning in circles, which is not the normal sensation of vertigo that I get.

It took a few minutes after the cessation of the water for the vertigo to subside, which is again perfectly natural. Once I felt normal again, I had to rest for five minutes before the procedure was repeated, this time hot water in the left ear. Again, vertigo after a few seconds, but this time it felt as if I were spinning in space, a 3-D sensation as opposed to the 2-D sensation in my right ear. Once more, this was not the sensation of vertigo that I have when lying in bed.

After a further rest period, I had cold (30 degrees) water introduced into my right ear. This produced no subjective sensation at all, although the technician said that the electrodes did detect some vertigo. After the mandatory five minutes of rest, cold water was introduced into the left ear, which almost immediately caused vertigo. I think that the intensity was less than with the hot water, but I don't recall exactly.

After the mandatory rest period, I was free to go. I felt a little washed out but otherwise ok. After about another hour, I felt totally normal. Although I was promised the results almost immediately (the same day), they have still to arrive, so I don't know whether a problem was detected in my balance system. The technician mentioned something about a non-localised problem, meaning that there is something wrong but that the tests didn't point to a specific location or cause. Hopefully the ENT doctor (or the neurologist who I will see afterwards) will be able to decipher the results and find the reason for the vertigo and headaches.

I note with pleasure that I haven't had a single bad headache in the past three weeks (and only one mild one). I was given new medication for headaches exactly at the same time of that last severe headache; this is a mild opiate along with paracetamol. So far, I have taken only one pill, which certainly got rid of the headache but gave me terrible gastric reflux pain. Fortunately, I haven't been required to repeat the experience of taking this pill, so I don't know whether the reflux was a direct consequence of the medication (let's hope not).

Update: the results arrived about half an hour after posting the above. They read "There is no spontaneous nystagmus. LT beating nystagmus recorded with positional test. Oculometric tests are normal. Bithermal caloric test is within the normal limits".

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