Karen Sadler
Copyright 2002

I wish I did not have to explain this disease under these circumstances. But I have to, out of love and respect for Joanie, and to hopefully prevent this from happening again. Knowledge is power, and it is up to us as a community who share the experience of hearing loss, to provide that power to all of the members of our SayWhatClub, and to those we hope will come looking to us for help.

Joanie had a disease which arises spontaneously. The name for this disease is neurofibromatosis. There are a couple of types of Neurofibromatosis: Type I and Type II. When you look in medical journals, you rarely see the entire word neurofibromatosis. Instead you will see NF1 or NF2. NF2 is the one we will be discussing in this article, because it is this type that Joanie had.

I looked in a very technical paper concerning NF2 that is available on PubMed, and they do know that NF2 is on chromosome 22. One of the 'suppressors' for tumors in NF2 is either missing or mutated. Most of our cells contain pieces of genetic material that tells cells to die off. If this is missing or mutated, the cell may never get the signal to quit growing. To an extent this means that NF2 has a genetic component. It gets complicated from there. Apparently though this may run in families, the gene that causes NF2 is NOT ALWAYS EXPRESSED. What this means is that someone, somewhere in Joanie's family may have had this, but outside factors (environment) caused it to be expressed in Joanie, but not another family member. Like many diseases with genetic origins, something else acts as a trigger. It could be as simple as exposure to environmental toxins. Usually when I see so much research, and no agreement as to what is going on here, that means doctors just don't know yet. As per usual, this recent paper indicated they now know that there is a NF3 (first time I've heard of that), and I suspect that there are probably more 'types' that we just don't know anything about yet. This is typical. Thirty years ago there were only a couple of types of hepatitis: Now we are up to Hepatitis G!

A neuroma is a tumor. When people say the word tumor, everyone automatically thinks CANCER! This is a fallacy that is perpetuated by the news media, which does a grave disservice to their readers when they do not check out their facts. In order to fully understand about neuromas, it is vital that people understand that tumors are not always cancerous. A tumor is just an overgrowth of cells, a mass that should not be there. An abnormal mass is called a neoplasm. Neo means 'new'. Plasma means 'cells'.

A neoplasm or tumor can be benign or malignant. A benign tumor is just an overgrowth of cells. When a person has a cancerous growth, the cancer can grow and those cancer cells can leave the tumor itself. These cells invade other organs, and in the process of growing release toxins that kill neighboring tissues. A benign growth such as a neuroma does not release any toxins. These tumors grow slowly over a long period of time. Even though they do not release toxins, they can cause problems of their own as they get larger.

NF1 and NF2 like to pick on the eighth cranial nerve. This nerve is the one providing people with hearing. Around nerves is a covering, kind of like the covering on electrical wire and for the exact same purpose. Why do manufacturers put insulating covering on electrical wire? To keep the electrical current from leaving the wire. The covering acts to continue the conduction of electrical current from the electrical socket to your electrical appliance (like a toaster). If that insulation was not there, the current would all be lost into the surrounding environment (besides the fact everyone would get shocked!). This is the same mechanism that occurs in the human body with neurons and nerves. There is insulation along most nerves, which is made up of a different type of cell called Schwann Cells. In some people like Joanie, the genetic part of these cells that tells them to quit growing is either missing or has mutated somehow. The cells never get the message to stop growing or die off, so they just keep going and going.

If you take cells like these and put them into a petri dish and give them the right amount of neuronal growth factors, they will just explode in growth. Normal cells will grow to the edge of the dish and then stop. These cells grow to the edge, then start layering cells on top of cells. What ends up happening if you let them keep growing in the lab, is that they will actually push the top of the petri dish off and spill over.

The brain is encased very well in a limited space called the skull. Except in newborns, the skull cannot change its shape or increase in size. That's because the skull is made up of bone. When a neuroma/schwannoma grows, even though it is not malignant and cannot move into other systems, the growth starts to crowd out the brain, and this puts immense pressure on the brain.

Above is a picture of the brain that all of us have. The pons, the medulla oblongata, and the midbrain are all part of what is considered the brainstem. This part of the brain is considered to be evolutionarily the oldest part of the brain. Without the brainstem, there is no life. Every mammal, reptile, and bird has a brainstem. It controls breathing and awareness or consciousness for all of us. If it is damaged (and it is very fragile), the person will go into a coma and die.

The cranial nerves all 'start' at the brainstem. The acoustic nerve (VIII cranial nerve) has its beginnings at the pons.

Above is a picture of the 'underbelly' of the brain. The odd green thing is the pons. This area not only has several cranial nerves coming from it, but the ponses are responsible for breathing in us.

1. Motor (minor) root of trigeminal nerve 2. Sensory (major) root of trigeminal nerves 3. Basilar sulcus of pons 4. Vestibulocochlear nerve 5. Facial nerve 6. Ventrolateral sulcus of medulla oblongata 7. Olive 8. Circumolivary bundle 9. Pyramid of medulla oblongata 10. Ventral (anterior) median fissure 11. Pyramidal decussation

As you can see from the pictures above this is a smaller area of the brain, but it is extremely busy. Gets a lot of information from our ears about hearing and balance, from our facial nerves about movement and taste, etc. Lots of stuff that I am not going to go into here. What is important is that this small area of the brain is in charge of breathing.

Back to neurofibromatosis. Like I said before neurofibromatosis really likes the auditory/acoustic/8th cranial nerve for some odd reason. Lots of theories why, such as the amount of vibratory input increases the electrical/chemical stimulation and the cells which don't have a 'stop' mechanism likes to feed on that. Sounds like science fiction right? Actually, our bodies are better storytellers than many who write science fiction, and it certainly is stranger! As a neuroma grows larger, it starts to compress the brainstem area and also the cerebellum (which is behind the pons and at the back of your head where it attaches to the neck). Not only does the growing tumor impact the hearing of the patients, but also it starts to affect balance (the cerebellum controls a lot of our balance mechanisms), and can initiate headaches.

The patient starts to suffer from tinnitus and hearing loss. They often complain of dizziness and some unsteadiness, but when tested for true vertigo like the type that happens in people with cochlear problems, they test negative. Many doctors are unfamiliar with the problems of NF and will miss early symptoms. The type of hearing loss that these patients exhibit usually waves a red flag in front of ENTs. The best way to describe this loss is that these patients can hear sound in the ear affected (usually starts with one, then goes to the other one), but they cannot discriminate speech. You can make the sound as loud as you want, but they still will not be able to tell the audiologist what is said. This differs significantly from age-related hearing loss or hearing loss due to disease like rubella or meningitis.

If the doctor suspects a neuroma, usually they start out testing with an auditory brainstem response test. If this indicates the suspicion is correct, the doctor orders a MRI and/or a CAT scan with contrast (meaning some type of radioactive dye is used). MRIs are the best method for finding neuromas and are nearly 100% correct. Neuromas, which are small, can be easily removed using microsurgery methods. As I said before, because they are not cancerous/malignant, usually chemotherapy and radiation therapy is not necessary.

Joanie had type 2. NF2 is the rarer type of neurofibromatosis. Only one in every 100,000 gets acoustic neuromas. This one has another name: Bilateral Acoustic Neurofibromatosis. It is also called an Acoustic Schwannoma. These tumors grow very slowly at the point of origin, meaning they stay where they start. They always start on one acoustic nerve in the bony part called the internal auditory canal. There are actually two cranial nerves that lie together here and follow basically the same path. The other nerve is the facial/trigeminal nerve. It can become involved when the tumor gets larger and starts to put pressure on this nerve. This is what happened with Joanie. Her first inkling of a problem was not hearing loss for some reason. The growing tumor put a lot of pressure on her facial nerve and she went to see the dentist because of pain in her mouth. She had many operations. The last time, she had developed tumors of some kind (I don't know which type yet, but probably gliomas from the support cells to neurons) on her optic nerve. They needed to be removed to prevent blindness. This is where I get a little confused, because technically Joanie should not have kept getting neuromas, yet she had developed more tumors. The type of tumors she had on her optic nerve may have been different than the original tumors that caused her to lose her hearing. In fact, I double-checked and most probably the tumors on the nerves leading to the eyes were gliomas. Gliomas are much faster growing tumors, and they involve the cells that support neurons in the brain. The Merck Manual, which is the 'bible' for doctors, says the criteria for a determination of a person having an acoustic neuroma Type2 is:

One of the following must be present:

Bilateral (both sides) 8th-nerve masses seen with CT scan or MRI.
A parent, sibling, or child with type 2 Neurofibromatosis and either a uni-lateral 8th-nerve mass,
or
any two of the following:

neurofibroma
meningioma
glioma
schwannoma
juvenile posterior subcapsular lenticular opacity

I don't want any of the readers of this on the SayWhatClub to be fearful they may have this condition or NF1. Even though NF1 is a fairly common genetic disorder (one out of every 3000 to 4000 people), if your parents did not have NF1 or NF2, then you won't have it. It is an autosomal dominant disease -- you cannot 'catch' it from other people. If you do not have NF, you cannot pass it on to your children.

Even more important is the fact that many people live long and productive lives with both these conditions. The progression of the disease and even the symptoms vary from person to person, even in families. As long as doctors can keep an eye on tumor growth and surgically remove the tumors, there is always hope. Most of these people will go deaf at some point. But as Joanie's sister Diane stated in her biography of her sister, Joanie kept living a good life. She finished two degrees after the first tumor removal. She traveled. She helped other deaf and hard-of-hearing people in her job. Probably more important than anything, she made us all laugh. Even though I was not able to go to the conference in Colorado, I heard more about the 'colored-condoms used as balloons and water balloons' than any other story. It was definitely in keeping with Joanie's outlook on life. Her courage and her sense of humor inspired all of us.

References:
(Guys and Gals: As always be very aware that the below are references not recommendations! Be very suspicious of charities, since many are just put up as moneymaking organizations, and charitable funding is often misused. Please use caution when approaching these groups.)

PubMed Article (warning: extremely long winded!)
http://www3.ncbi.nlm.nih.gov/htbin-post/Omim/dispmim?101000

Merck Manual On-Line:
http://www.merck.com/pubs/mmanual/section14/chapter183/183f.htm#A014-183-1219

The National Neurofibromatosis Foundation
http://www.nf.org/

Neurofibromatosis, Inc.
http://www.nfinc.org/

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