Hearing Implants

Bilateral vestibular schwannoma (VS) tumors are the most common tumors for SWN:NF2, previously known as neurofibromatosis type 2. Bilateral VS or single-sided VS may also develop in individuals with the SWN:(SMARCB1/LZTR1) gene, SMARCB1/LZTR1, or NF3. This same tumor at the same location is sometimes called an Acoustic Neuroma (AN), for individuals who do not have them on both sides.

However, outside of SWN, an AN tumor has a 95% chance of spontaneous growth, not connected with a genetic mutation. However, a few of these individuals with a single AN might have SWN:SMARCB1. More research is needed; individuals with these needs to talk to their Neurologist or Neurosurgeon.

Hearing loss that is the result of the condition VS is a result of damage to the cochlear nerve (acoustic nerve), the connection of the nerve between the Cochlea and the brainstem. Traditional hearing aids that amplify sound might offer help while the nerve starts to become damaged. As more damage to the nerve occurs, a Hearing Aid, which only amplifies sound, will become ineffective. The next step is a cochlear implant (CI) and thanks to medical advancements, many people with NF2 do well with hearing from a CI for many years. If the cochlear nerve breaks completely; something that would be confirmed or rejected as a result of auditory brainstem response (ABR) test, sometimes also called brainstem evoked response audiometry (BERA), only an auditory brainstem implant (ABI) will offer any sound.

Cochlear Devices

Individuals with Schwannomatosis NF2 are at risk of hearing loss in both ears early in life. Hearing Options: Hearing Devices

When Hearing Aids are no longer an option, there are options to regain hearing from hearing aids (sound amplification), and hearing implants will help. The issue that follows is which is ideal for an individual's specific situation at a given point in time. Options are:

1. Cochlear Implant (CI)
2. Auditory Brainstem Implant (ABI)
3. Baha (Bone-anchored hearing aid)

There are two brands or Hearing Amplants; Choclear International and Advanced Bionics.

The Auditory Brainstem Implant (ABI) is based on the classic cochlear implant (CI) but uses a different stimulation electrode.^{[1 (Acta Oto-Laryngologica)]}
"The first ABI surgery in a neurofibromatosis type 2 (NF2) patient with the MED-EL device took place in the year 1997. Later, the indication of ABI was expanded to non-NF2 patients with severe inner-ear malformation, for whom a regular CI will not be beneficial. Key translational research activities at MED-EL in collaboration with numerous clinics investigating the factors that affect the hearing performance amongst ABI patients, importance of early ABI implantation in children, tools in pre-operative assessment of ABI candidates and new concepts that were pursued with the MED-EL ABI device."^{[1 (Acta Oto-Laryngologica)]}

There are three different forms of hearing loss:

1. Sensoriineural
2. Mixed
3. Condictive

1. Sensorineural

Aging, Noise Damage, Drug Side Effects, Auditory Tumors, and Blast/Explosion.

2. Mixed

Genetic Disorders, Infections, and Head Trauma.

3. Conductive

Fluid, Foreign Objects, Allergies, Ruptured eardrum, and Impacted earwas.

Sources

1. NextGen ABI Receivers: Hearing Implant: Cochlear Implant - Auditory Brainstem Implant.
   https://www.engadget.com/2019/10/20/soft-platinum-hearing-implants/?guccounter=1&guce_referrer=aHR0cHM6Ly9hcHBsZS5uZXdzL0FpUDRNZnB1YVM2LU9WOW1oVm42LVB3P2ZiY2xpZD1Jd0FSMmxrV0dGTWxWeUZnOUYtT3RoZXN1U0NQU2dSZnlKNVVIdWNETmFpRFlKSXhSNmJBNWY0a2N5TDQw&guce_referrer_sig=AQAAAAsxgtvsSIWuzoR8KvIhLs1CV5V3btZTbsp5p9-SC-otKCIW4bf0R3BtBPQktKOBpgOUgDDYhM8aa5Ys3ZaStg9xZg0F_kMk_LZt469SRkGk5Dziwot5p346GaOz9VVFzSE6CYA7RpmgzwWXHE9tEspijw4s_nmgqwhqJwRZRXL9
2. Davis, Neil L., Jamie M. Rappaport, and James C. MacDougall. "Cochlear and auditory brainstem implants in the management of acoustic neuroma and bilateral acoustic neurofibromatosis." McGill Journal of Medicine 3 (1997): 115-120.
   Source: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.557.3776&rep=rep1&type=pdf | DOI: 10.1.1.557.3776
3. Bosch, Martina M., et al. "Ophthalmologic findings and long-term course in patients with neurofibromatosis type 2." American Journal of Ophthalmology 141.6 (2006): 1068-1077.
   Source: http://www.ajo.com/article/S0002-9394(06)00015-8/fulltext | DOI: 10.1016/j.ajo.2005.12.042
4. Samii, Madjid, and Venelin Gerganov. "Neurofibromatosis Type 2 and Other Bilateral Cerebellopontine Angle Tumors." Surgery of Cerebellopontine Lesions. Springer Berlin Heidelberg, 2013. 315-374.
   Source: http://link.springer.com/chapter/10.1007%2F978-3-642-35422-9_6 | DOI: 10.1007/978-3-642-35422-9_6
5. Vincent, C. "Auditory Brainstem Implants: How Do They Work?." The Anatomical Record. 295.11 (2012): 1981-1986.
   Source: http://onlinelibrary.wiley.com/doi/10.1002/ar.22588/full | DOI: 10.1002/ar.22588
6. Cochlear. "Cochlear Nucleus 6 Manual" (2017) Source: http://www.cochlear.com
7. Cochlear. "Cochlear Freedom Manual" (2010) Source: http://www.cochlear.com
8. Journal of Educational Audiology. "An Electrostatic Discharge (ESD) Control Program for Children with Cochlear Implants." (2002)
   Source: http://c.ymcdn.com/sites/www.edaud.org/resource/resmgr/imported/02_McGinnis.pdf
9. Hexter A, Jones A, Joe H, et al. "Clinical and molecular predictors of mortality in neurofibromatosis 2: a UK national analysis of 1192 patients" Journal of Medical Genetics Published Online First. (August 2015)
   Source: http://jmg.bmj.com/content/early/2015/08/14/jmedgenet-2015-103290.short | DOI: 10.1136/jmedgenet-2015-103290
10. Ardern-Holmes, Simone, Gemma Fisher, and Kathryn North. "Neurofibromatosis Type 2: Presentation, Major Complications, and Management, With a Focus on the Pediatric Age Group." Journal of Child Neurology. 32.1 (2016): 9-22.
    Source: http://journals.sagepub.com/doi/abs/10.1177/0883073816666736 | DOI: 10.1177/0883073816666736
11. Schwartz, Marc S., et al. "Auditory brainstem implants." Neurotherapeutics. 5.1 (2008): 128-136.
    Source: http://www.sciencedirect.com/science/article/pii/S1933721307002565 | DOI: 10.1016/j.nurt.2007.10.068
12. University of Kansas. Researchposters. "ABI and American Med-El Trial in the United States" (June 2016)
    Source: https://www.researchposters.com/Posters/NASBS/NASBS2017/P180.pdf
13. Unknown "Cochlear Implant Mapping."
    Source: https://funnyoldlife.wordpress.com/2010/05/04/cochlear-implant-mapping
14. Mayo Clinic. "Auditory Brainstem Implants: Recent Progress and Future Perspectives" Neurosci., 29 (January 2019) https://www.frontiersin.org/articles/10.3389/fnins.2019.00010/full?fbclid=IwAR0TiFLwHdpsE4pk3uvu4eE5dCqPemc6a05wAw5XJzrhVRxLDZyensOENac doi: 10.1097/00005537-200303000-00015
15. Advanced Bionics www.advancedbionics.com