ANA Discussion Forum
General Category => Inquiries => Topic started by: another NY postie on July 01, 2009, 12:19:57 pm
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Hello. I just came back from my 4th dr. appt (was diagnosed three weeks ago and it seems like Acoustic Neuroma is a magic password because I have gotten appts quickly in NYC). 3 neurotolgists and 1 neurologist. The last one just scheduled me for an ABR. Not sure why no one else mentioned this test.
Did I understand correctly that this will tell me if my AN is affecting the cochlear? I already have some hearing loss so I am a little unclear what this will tell me as opposed to my audiology report?
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I had an ABR test PRIOR to diagnosis - after that, the ENT ordered the MRI...just know that the ABR gave a good indication that there was something in my head...I suppose I should know more about what the test showed, but I don't. Know there are folks here that do have the exact scoop on it, and will let you know!
Cindy
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I got the impression that it would tell me more information on how much the AN is affecting the cochlear. Of course, I took notes but now I can't understand my own notes :).
I wrote: if wave form from cochlear is sharp, cochlear is uninvolved, if wave form is wavy, cochlear is involved.
What I am not clear on is what exactly does that tell me in relation to my AN? I already have hearing loss (small) so it has affected my hearing nerve, but does that mean it can affect my hearing nerve but not my cochlear?
My AN is in the lateral portion of my IAC. I think I understood that this will give him a better idea of how realistic hearing preservation would be if I chose surgery?
(I have heard the following: dr.#1=70%, dr#2=50%, dr#3=50-75% chance)
Thanks,
Cheryl
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From what I understand, ABR (auditory brainstem response) audiometry is a test of auditory pathway and brainstem function in response to auditory or (click) stimuli. This could concievably have something to do with the cochlea sending a signal to the brainstem, I'm not really clear on that, but since t is to test the brainstem response to the click stimuli, I guess it makes sense that the signal to the brainstem would come from the cochlea and so the ABR might test both.
Wendy
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I think mine was done to see if the hearing nerve itself was performing as usual. In my case it was because I did not have an AN. Mine was a meningioma, which did not affect the hearing nerve.
Priscilla
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An ABR, or auditory brainstem response test, tells you something much different than an audiogram. An audiogram simply tells you if you have hearing loss, but it doesn't tell you whether this is due to a problem in the cochlea or with the hearing nerve. The ABR measures the response of the hearing nerve to stimulus at several points (five, if I remember correctly) along its length. It used to be that ABR tests were relied upon more heavily to determine if an AN was present, the assumption being that impaired response meant a tumor must be degrading the nerve's function. But some people can have an AN without the ABR showing degraded response; those people usually have well-preserved hearing despite their AN. So now an MRI is the gold standard for diagnosis.
So why then is an ABR still used? The way Dr. Derald Brackmann (world renowned neurosurgeon at House Ear Clinic) explained it to me is that by seeing how many points along the hearing nerve are compromised and how badly (i.e., by measuring the amplitude, or strength, of the response), one can reach a conclusion as to how likely hearing can be preserved with surgical resection of the tumor. When Dr. Brackmann looked at my lousy ABR results, he concluded that surgery would surely leave me deaf on my AN side -- even with using the retrosigmoid approach, which is often used in an attempt to preserve hearing when a middle fossa approach isn't feasible. That is why he recommended I have radiation treatments instead of surgery (the chances of hearing preservation were higher for me with radiation, due to the size and location of my tumor).
It's a good thing to have an ABR and have a doctor look at the results who knows its value as a predictor of treatment outcome vis-a-vis hearing preservation (some doctors merely look at it as an outdated and inaccurate method for determining if someone has an AN). Be involved in your test results. Ask what the practical ramifications of the results mean. By doing so, you will be better able to make an informed decision as to which treatment is best for you and avoid the regret of learning too late (after treatment) that another approach might have left you with more function or had some other positive benefit.
Best wishes,
TW
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Tumbleweed,
Thanks for the great explanation. I had a vague idiea of what the ABR was for, but your explanation cleared it up for me, and I'm sure for many others too.
Wendy
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Another thing ABR can be used for is to see if the hearing nerve can be monitored during surgery. The Skull Base Surgery Team normally has someone there to monitor the facial nerve, with the idea that if surgery is compromising the facial nerve the tech can inform the surgeon. They can also monitor the hearing nerve as long as your hearing isn't already too far gone to make monitoring possible. For hearing nerve monitoring, they have a speaker that "thumps" in your ear, and the tech can see a resultant "bump" on the monitor screen. During surgery, they send the "thump" periodically, and look for the "bump" on the monitor, and if the response on the monitor changes the tech can inform the surgeon. Facial nerve monitoring is one of the reasons that facial nerve preservation outcome has improved for AN surgical treatment.
During my pre-surgery testing it was found that my hearing, at -70 db loss, was too far gone for the tech to be able to discriminate the "bump" from background noise. This meant that hearing nerve monitoring would not be possible during surgery.
Ask if your AN surgical treatment team includes somone to monitor the facial and hearing nerves.
Regards,
Rob
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Tumbleweed, Dr Brackmann is one of the two doctors who told me to get the test so he could better assess whether hearing preservation is truly possible for me given the location of the tumor which is in the lateral portion of the canal. I have also been reading many abstracts and it seems that long term hearing preservation stats are higher if the tumor is on the superior portion of the vestibular and not the inferior. I am not sure how they can determine that. There seems to be so many variables in this that I don't know how you ever make a decision! Did your radiology save your hearing?
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CK has so far preserved my hearing fairly well (fantastic compared to certain deafness had I had surgery), although I've lost 20 dB of hearing in only my midrange frequencies since treatment one year ago.
The reason why one has a better chance of hearing if the AN originates from the superior vestibular nerve is that the inferior vestibular nerve (the other possible origin) is closer to -- actually immediately above -- the hearing nerve, so an AN on the inferior vestibular nerve is more likely to impact the hearing nerve. From top to bottom, the cranial nerves that traverse the length of the internal auditory canal are: facial , superior vestibular, inferior vestibular, and hearing nerve.
Best wishes,
TW
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So I would assume that since mine is very small (5mm) but I already have hearing loss, mine is probably the inferior...just my luck >:(
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Hi Cheryl,
i promised I would let you know how I made out.
I did not have the ABR test, but it turned out my hearing and face nerve were reversed, Hearing on top and facial on bottom. Because the tumor was right next to the cochlea, DR. Roland did not expect that I would have hearing after the surgery but I do!!!! I can hear very well, I also have no nausea, double vision or dizziness. Just a little headache and unfortunately some temporary facial weakness, but they say the nerves are fine I just need to give it some time. All is well. NYU was wonderful, the Doctors were great. Good Luck and know in this day and age that even major surgery is nothing to be afraid of , I worried way too much and everything was ok!
Take care,
Darlene
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Darlene - I am SO excited for you!!! It sounds like you ended up with best case scenerio and hearing to boot! Hurrah!!!! I have appt. with Roland on 17th - this gives me hope for my hearing...I was feeling pessimistic because of proximity to cochlea. Speedy recovery -keep me posted :D :D :D
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I don't know why I didn't mention this before but if you aren't busy, some of us from NYC/NJ are getting together for lunch on Saturday at Brendan's Bar in 35th Street b/w 5th & 6th Avenues. It would probably do you good to see for yourself there there is life after AN surgery if you can make it. We are meetinig at 12:00. If you'd like to attend, PM me and I'll give you my phone number for just in case purposes.
Wendy
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Thanks, Wendy...Neal had mentioned it to me and I have been trying to figure out how I could swing it but weekends are extremely busy for me with my kids so I won't be able to do it tomorrow :( Does this happen just once a year? I would so like to meet everyone in person! Too bad it is not today as I am headed to Mt. Sinai in about 15 minutes for my ABR test! Oh, well, enjoy your lunch and I will make it next time
Cheryl
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Hi Cheryl,
We got together twice in the past year, but have talked about getting together more often. I hope you can make it next time. I'm sure you've had the ABR by now and things look more promising than you've been thinking. Keep us posted.
Wendy
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Ok, I had the ABR and basically I don't know anything. She said I could have a copy of the report if all things were normal right away (she knew I have an AN) but of course, I had an abnormal reading which she then said was normal for one having an AN (!?!?!) so she said she couldn't begin to say what dr. will say...had to write up the report....the good news she said is the 5th wave which she said was the most important one, was normal but there were other waves not so hot. I really don't know what it all means and now have to wait until next week to see if that means my cochlear is involved and what that means for hearing preservation outcome. I really get the feeling this is all a shot in the dark and some come out with hearing and lots more don't....I feel frustrated to say the least.