[Special Topic on Hearing Impairment]The Department of Otolaryngology and Neurology team up to implant the brainstem receiver ABI to help restore hearing

Text: Yang Qianni Compiled by: Liang Yingxiu

(Kuala Lumpur News) There are some situations when cochlear implants cannot help hearing-impaired people, such as congenital absence or hypoplasia of the auditory nerve, acoustic neurofibromas and cochlear ossification.

ABI bypasses the damaged part of the pathway (the cochlea or auditory nerve) and places the electrode wire directly in the cochlear nucleus located in the brainstem.

When people think of hearing impairment, they usually think of hearing aids first. A hearing aid acts like an amplifier to amplify sounds, using the hearing-impaired person’s residual hearing so that the sounds can be transmitted to the brain and the sound can be felt.

There are many types of hearing aids on the market, with different amplification capabilities. People with different levels of hearing impairment can choose a suitable model based on their own hearing level. When hearing impairment is extremely severe (profound), hearing aids cannot work, and other methods need to be considered to help them, such as cochlear implants.

The premise is that the patient’s cochlea is in good condition, the auditory nerve and brain function are normal, and the patient is highly cooperative and willing to attend rehabilitation sessions after surgery.

Allow the patient to hear sounds

Dr. Tang Ing Ping, Professor at the Department of Medicine at the University of Sarawak and Consultant of Otolaryngology and Head and Neck Surgery at Sarawak General Hospital, pointed out that cochlear implants cannot help hearing-impaired people in some cases, such as congenital absence or underdevelopment of the auditory nerve, which is like a broken bridge. Bridge, even with hearing aids or cochlear implants, sound cannot travel from the cochlea to the brain.

“In addition, acoustic neurofibromas can cause hearing loss over time, and treatment includes surgical removal of the tumor and nerve cords.”

Furthermore, cochlear ossification is one of the contraindications to cochlear implantation, and approximately 5% to 35% of meningitis cases will lead to sensorineural hearing loss. This is because the hardened cochlea has no hole for the electrode array connected to the implant to be inserted into the cochlea.

“However, as long as these patients’ cochlear nuclei and brain function are normal, such as they are not delirious or unable to speak, we can help them rebuild their hearing through Auditory Brainstem Implants (ABI) .”

In fact, the operating principle of ABI is similar to that of cochlear implants. It also consists of an external sound processor and an internal implant, which converts the collected sound into electric current, which then stimulates the implant so that the patient can hear the sound.

The biggest difference between the two is the location of the internally implanted electrode wires. ABI does not place electrode wires in the cochlea, but bypasses the damaged part of the auditory pathway (cochlea or auditory nerve) and places it directly in the cochlear nucleus located in the brainstem. In this way, the sound no longer has to rely on a “bridge” and can be transmitted directly to the brain.

At present, ABI is mainly provided clinically to patients with bilateral hearing loss who cannot benefit from hearing aids or cochlear implants. Neurofibromatosis Type II (NF2) is the most common indication.

“NF2 is a genetic disease of multiple nervous system tumors. Patients are usually very young, about ten or twenty years old. Schwannomas may appear throughout the body, with the auditory nerve being the most commonly affected part. Although tumors It is benign, but if it compresses the spinal cord, it can lead to paralysis of the upper or lower limbs. Once it compresses the nerves of breathing or heart, it can be fatal.

He emphasized that ABI surgery is relatively complex and requires joint surgery by an otolaryngologist and a neurosurgeon who specializes in lateral skull base surgery.

Doctors who perform surgeries require special training

Simply put, the otolaryngologist will drill a hole from behind the ear to create a “pathway” to the base of the skull. Then the brain doctor takes over, opens the meninges to see if the tumor needs to be removed, and finds the cochlear nerve nucleus to place the electrode wires. Afterwards, the otolaryngologist will carefully close the surgical site to avoid bleeding or outflow of cerebral spinal fluid (brain water), which may cause bacterial infection.

“The risk of ABI surgery is mainly that there are many important blood vessels and structures around the brainstem, such as the aorta, facial nerve, 9th, 10th and 11th cranial nerves, etc. If accidentally damaged, it can lead to unilateral facial paralysis and swallowing disorder. etc., so surgeons need to be specially trained to reduce risks.”

“In general, surgery needs to avoid harming surrounding structures, prevent bleeding, that is, hitting arteries or veins causing cerebral hemorrhage, ensure the surgical environment is clean, the surgical site is well closed, and prevent bacterial infection causing meningitis, etc.”

Although the surgery is challenging and the risks are higher than cochlear implantation, it should not be a big problem as long as the doctor is specially trained. As far as my own experience is concerned, after becoming an otolaryngologist, you need to undergo special training before you can perform ABI on your patients.

Accepting patients with ABI

Less than 10 people in Malaysia

The first ABI surgery in Malaysia was performed at the Kuching General Hospital in Sarawak in 2016.

Until now, the number of patients suitable for ABI has been small, less than 10 in Malaysia, and most of them are treated in Kuching.

Since ABI is a relatively new medical technology, the government does not yet have relevant programs to subsidize these patients. Although government hospitals bear most of the surgical costs, compared with about RM30,000 to RM50,000 for surgery in private hospitals, patients only have to bear one to two thousand ringgits, but this does not include the cost of the ABI device.

The price of ABI device is about 80,000

Zheng Yingping said that the price of the equipment required for ABI is about RM80,000, which is not affordable for ordinary families. Therefore, he especially wants to thank Sarawak Women, Children and Community Harmonious Development Minister Datuk Seri Fatimah Abdullah. With their enthusiastic help and several special grants, several patients have been able to undergo ABI surgeries and regain their hearing, including a Chinese young man who was recently approved.

“I also have to mention the influence of the Sin Chew Foundation. I would like to thank them for raising money for a girl with Goldenhar Syndrome. They collected RM70,000 in just 2 days. ABI was successfully carried out. After the surgery, she no longer needs to live in a silent world.”

Thanks to the care and assistance of many kind-hearted people, these hearing-impaired patients are able to receive help from innovative medical technologies, which often changes their lives.

He said that the most memorable case for him was the first patient in Malaysia to receive ABI. He suffers from NF2 and has poor hearing and needs to wear hearing aids, but suddenly one day, he can no longer hear sounds at all. “After an MRI examination, it was discovered that he had a tumor on his auditory nerve, which could only be removed through surgery.”

At that time, ABI had not yet been introduced in Malaysia. Without this treatment option, he had to start learning lip language and sign language to maintain his daily life and work. What is gratifying is that his girlfriend has never left him, and they even started a family together and gave birth to a daughter.

He cried when he heard his daughter’s voice for the first time

In 2013, Zheng Yingping returned from his studies. Later, with funding from the Sarawak government, he worked with a brain doctor to perform ABI surgery on him. After that, he also actively cooperated with rehabilitation. At first, he learned to lip read the sounds he heard in his head. Now he can hear 70% of the sounds and his speech is no different from that of a normal person.

“The most touching thing is that although the patient’s daughter was born four or five years ago, he has been able to communicate only through lip language and sign language. It was not until after the operation that he finally heard his daughter’s voice for the first time, and he almost cried with joy. It was seeing these patients successfully regaining their hearing and living a different life that made me even more convinced that this job is of great significance.”

All in all, the focus of hearing impairment is early detection, early intervention and early treatment. If you have any hearing problems, you should get checked out promptly because some causes can be reversed. Even if there is a tumor, it can be removed before it becomes huge, and the results of whether it is a cochlear implant or ABI will be better.

ABI surgery takes 4 to 5 hours

Question 1: How long does ABI surgery last?

Answer 1: If the tumor does not need to be removed, ABI surgery takes an average of 4 to 5 hours: it takes about 2 hours for an otolaryngologist to open a “door”, and about two to three hours for a brain surgeon to implant electrode wires. If the tumor needs to be removed, it will take an additional 3 to 12 hours, depending on the size of the tumor.

However, patients do not need to worry. When the cause of hearing loss is diagnosed, doctors will use magnetic resonance imaging (MRI) scans or computed tomography (CT) scans to confirm the condition, and whether there is a tumor is already known.

The earlier the treatment, the better the effect

Question 2: Are there big differences in the postoperative outcomes of different ABI cases?

Answer 2: In fact, surgical factors and patient factors determine the effectiveness of ABI. If the operation is successful, all 12 electrode channels can be activated, and there are no surgical complications, then the focus lies on the patient himself.

The first is the condition. If it is due to cochlear ossification, usually the effect of ABI is very good; if it is due to acoustic neurofibroma, it depends on the size of the tumor and how long it compresses the cochlear nerve nucleus. These will affect the recovery of neurological function, which cannot be done before surgery. Predicted.

However, NF2 patients are relatively rare, and there may only be a few thousand ABI surgeries worldwide. Due to the complexity of the surgery, the strict conditions for selecting patients, and the limited data collected, it is difficult for us to predict the postoperative effects for NF2 patients.

Although the tumors of some NF2 patients have compressed the cochlear nerve nucleus for five or six years, the results after surgery and reconstruction are very good; in some cases, although the tumors have only compressed the cochlear nerve nuclei for two or three years, the results may not be as expected. However, generally speaking, the earlier treatment is received, the better the results will be.

The last important factor that cannot be ignored is rehabilitation. If you do not cooperate with rehabilitation after surgery, no matter how simple the original condition is and how perfect the surgery is, it will be nothing more than empty talk. Rehabilitation is a lifelong matter for patients with cochlear implants or ABI. The first few years will be more frequent and the number of follow-up visits will be more. After the patients master the learning method, it will be easier.

Therefore, I will definitely counsel patients before surgery to let them understand the importance of rehabilitation. If they are not willing, I will not undergo cochlear implantation or ABI. In my many years of experience, the counseling component is also indispensable, and doctors cannot just implant a hearing device and leave it alone.

Sounds like a robot talking

Question 3: Are the sounds heard after ABI surgery normal?

Answer 3: Generally, depending on the patient’s wound recovery and self-healing status, we will “start up” after one or two months. According to feedback from patients, the voice they heard at first was like a robot talking in a movie, but the human brain is very powerful. After a period of training, the brain will adapt and adjust the rigid mechanical voice into a normal voice.

Therefore, a few months after ABI is started, it may sound weird, but when the brain gradually accepts it, it will not be a big problem. This also highlights the importance of speech rehabilitation and hearing rehabilitation.

Hearing restored after 3 months

Question 4: Cochlear ossification is a contraindication to cochlear implantation, and the patient needs ABI. So what should you do if the original cochlea ossifies after a cochlear implant is implanted?

Answer 4: Normally, cochlear implants do not need to be replaced for a lifetime, unless there is a huge brain impact such as a car accident, which is very rare. If the patient later suffers cochlear ossification due to some diseases, there is no problem, because the cochlear implant has been inserted and can still stimulate the nerve lines. If you want to implant a cochlear implant if the cochlea is ossified, it will not work.

“There is a female patient in her 40s who already had hearing loss on one side and later developed meningitis. I suggested that she implant a cochlear implant because cochlear sclerosis caused by meningitis often occurs very quickly (about 1 year). (internally). However, she was relatively resistant to surgery and decided to consider it first. As a result, 3 years later, she could no longer hear in both ears, and she decided to undergo cochlear implantation. Unfortunately, her cochlea was already boned at this time. Fortunately, she still has ABI as a treatment option.”

Under the rehabilitation treatment of a speech specialist and an audiologist, she walked into the clinic 3 months after the operation and saw me, and she took the initiative to talk to me. There was no problem in communication. While I was surprised at how quickly she recovered, I was also very pleased and felt that this job was of extraordinary significance.

3 common causes of hearing loss: seize the 1-week golden treatment period

Sudden hearing loss, tinnitus such as metallic high-frequency sounds, cicada calls, ear congestion, and dizziness may be symptoms of sudden deafness. You should seek medical attention as soon as possible to avoid missing the one-week golden treatment period.

After 42-year-old Mr. Yang got up, he found that his ears were stuffy and there was a continuous buzzing sound. He was not sure whether his hearing had worsened. He sought medical examination and found that he had “low-frequency” hearing damage in his left ear, which was close to “sudden deafness.” He took medicine urgently and had sexual intercourse. My hearing returned to normal.

Doctors pointed out that viral infection, vascular embolism, and hypothyroidism are all common causes of sudden deafness. The golden treatment period is one week. If you miss it, you may suffer hearing loss.

sudden hearing loss

Guo Naiwen, the attending physician at the Department of Otolaryngology, said that sudden hearing loss, tinnitus such as metallic high-frequency sounds, cicada chirping, ear congestion, a feeling of water in the ears, and dizziness may all be caused by sudden deafness. If symptoms occur, it is recommended to seek medical treatment promptly and receive treatment with high-dose steroids, vasodilators, or ear injections of steroids or hyperbaric oxygen.

Guo Naiwen explained that common causes of sudden hearing loss include viral infection, vascular embolism, hypothyroidism, etc. The examination includes blood tests, electrocardiograms, and auditory brainstem reflex tests.

He mentioned that the degree of hearing recovery from sudden deafness varies among different ethnic groups. The more severe the hearing loss is at first, the older the patient is, those with chronic diseases, accompanied by dizziness or tinnitus, and those who seek medical treatment too late, the recovery status will be less than expected; conversely, the hearing loss will be worse at the beginning. If the injury is minor, young, and seek medical attention promptly, the chance and condition of hearing recovery will be better.

Most cases occur in one ear

Guo Naiwen suggested that if you suddenly experience tinnitus, ear fullness, hearing damage or other uncomfortable conditions, you should seek medical advice and arrange a hearing check as soon as possible to avoid missing the golden treatment period for sudden deafness. Such patients should have a light diet, less salt, a regular work and rest routine, and adequate sleep to maximize their chances of hearing loss recovery.

Sudden deafness is an acute disease in the Department of Otorhinolaryngology. It is medically defined as a sudden onset of sensorineural hearing impairment in a short period of time (3 days). A hearing test shows that the hearing threshold for more than three consecutive frequencies has deteriorated by more than 30 decibels. The incidence rate is equal in men and women, most of them occur in one ear, and very few occur in both ears at the same time.

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