A Cochlear Implant is a specialized hearing device that consists of both a surgically-implanted and external component used to simulate natural hearing. This device is used to treat people with severe and profound hearing loss. The implanted component is placed under the skin, behind the patient’s ear, and connected to the auditory nerve of the brain. The Cochlear Implants are designed to receive sounds and convert them into electrical signals that bypass the damaged nerves, allowing the brain to interpret the electrical signals.
How has the use of Cochlear Implant technology grown?Cochlear Implants have been approved since the mid-ass’s but research on this technology grew in the essays. The first known implant was implemented in the 1 ass’s, but the patient could only hear static. By 1972, a few thousand people had successfully received the implant due to greatly improved technology. In 2002, it was estimated that 59,000 people had received Cochlear Implants and six years later, an estimated 1 50,000 patients nationwide had received the implant. From 2002-2008, the number of implant procedures nearly tripled as more people saw the value of the device.Cochlear Implants are a growing field, however only a small portion of the deaf community has been implanted with this device. What is natural hearing? With little or no hearing loss, a person hears using the natural hearing process (Figure 1): sound enters the ear (blue arrow), travels down the auditory canal to the ear drum (green arrow), transfers from the ear drum to the cochlea (or “inner ear”), and is converted by the cochlea into electrical signals (red arrow) that pass through the Vestibular cochlear nerve to the brain (purple arrow).The cochlea transforms sound into electrical signals using tiny hearing hairs inside it.
FIGURE 1 The natural hearing process. Image courtesy of housework’s. Com What causes deafness? In some deaf people, the hairs in the cochlea are damaged or missing, meaning the cochlea cannot convert the sound. In others, the eardrum is damaged, so sound cannot be sent to the cochlea. How does a hearing aid function? A hearing aid works by detecting sounds.
A microphone built into the hearing aid detects sound in the environment and delivers it to the processor located inside the hearing aid.The processor within the hearing aid then computes the sound frequencies and amplifies them. The hearing aid then livers the sound through the tone hook to a custom ear-mold that sends the sounds to the inner ear (Figure 2). The sound is then received by the ear drums just like normal hearing. A hearing aid is completely dependent on the natural functions of the ear. A hearing aid will not work for a person whose ear drum has been damaged. In that case, a hearing device that is independent of the natural functions of the ear would be necessary.FIGURE 2 Image courtesy of Boys Town National Research Hospital How does a Cochlear Implant function? A Cochlear Implant (Figure 3) attempts to replace the function of the cochlea tit a mechanical device.
Sound enters the microphone of the external portion of the device and a computer then processes the sound and converts it to a digital signal. The transmitter then sends the digital signal to the implanted receiver, which converts the digital signals to electrical signals. The electrical signals then pass through the implants electrode wire to the electrode array and into the cochlear nerve.The electrical signals then follow the nerve to the brain, where the brain processes them as “hearing’. FIGURE 3 Cochlear Implant Mechanism Diagram. Image courtesy Of the National Institute on Deafness and Other Communication Disorders (UNDID) What kind of Cochlear Implants are there? A Cochlear Implant is a unique kind of a hearing device, but comes in many varieties.
Since there are three Cochlear Implant companies (Advanced Bionics Corporation, Cochlear Corporation, and Mimed Corporation), there are three different kinds of Cochlear Implants.Each Cochlear Implant is designed based on the individual company’s perception and strategies. The possible differences between the three Cochlear Implants are sizes, processing features, and accessories. Processor Model. The Cochlear Implant processor sizes range from a box- shaped device worn like a pager to a behind-the-ear device like a hearing aid (Figure 4). The processors designed by the three companies do not function the same: one company generates a processor with 1 6 audio frequencies, while others produce 120 audio frequencies. Audio frequency determines the quantity different pitches ranging from low to high pitches.The more frequencies a processor can generate, the more pitches a patient can hear.
FIGURE 4 Left: Behind-the-ear implant processor. Right: Pager-like implant processor. Image courtesy of Chillers, Smith, LLC Image courtesy of Seemed.
Com Clutter & Voice Processing Strategy. Each Cochlear Implant manufacturer converts sound to an electrical signal differently. Cochlear Corporation uses the Speak processing strategy. Speak-utilizing processors separate the sound into twenty different frequency range filters. The processors then analyze the output of each of the filters to find the six strongest sound waves.The processor further reduces these to the strongest waves from all of the filters and notes the filter each wave originated in.
The processor then stimulates the corresponding electrodes in the cochlea. The Advanced Bionics Corporation’s processor uses either of the conversion processes “Compressed Analog” (CA) or “Continuous Interleaved Sampling” (CICS). In both processes, sound passes through eight filters and is compressed to a smaller data size. In the CA mode, the filtered signals are sent simultaneously to eight electrode pairs in the cochlea.In the CICS mode, the signals are sent in pulses to the eight electrode pairs at a maximum rate of 833 pulses per second per filter. FIGURE 5 CICS Method. Image courtesy of gosh.
Due. The Med-El processor is very similar to the Advanced Bionics processor, but notation no CA mode and sends pulses at a faster rate of 1,51 5 pulses per second per filter. It can also be programmed with a slightly-modified Speak strategy, using fewer filters and a larger pulse rate.
CA vs.. CICS: The Compressed Analog strategy provides the user with a highly- detailed signal that, in theory, should give the user a better-defined hearing simulation.When all the electrodes fire at once, however, the electric fields of the electrodes will sometimes interfere with each other, resulting in an unclear signal.
The Continuous Interleaved Sampling method attempts to alleviate this problem. Instead of firing all the electrodes simultaneously, the processor sends pulses to the electrodes, firing single electrodes in quick succession and eliminating interference. While the CICS method eliminates the electrode interference, it also produces a less-defined signal than the CA method. Compatibilities.Cochlear Implants are outfitted to be compatible with various electronic devices.
Many Cochlear Implants and hearing aids contain a telecoms, a small coil of wire that works separately from the microphone and produces an electric current when exposed to a magnetic field (Figure 6). The Hearing Aid Compatibility Act of 1 988 requires all wired telephones to be “hearing aid compatible. ” This means the telephone produces a changing magnetic field, creating an electric current in the telecoms that can be converted to a sound signal by the hearing aid or Cochlear Implant processor.
In addition, some telephones use radio frequencies to collaborate with the hearing aid or Cochlear Implants microphone. Today, many wireless and cellular telephones are also hearing aid compatible. FIGURE 6 A telecoms. Image courtesy of indignant.
Com Some devices, such as Compact Disc or MPH players, can be picked up y the microphone component of the Cochlear Implant. The microphone directly sends the electrical signal of the music player to the processor. There are two different microphone components: the T-Mice Microphone and auxiliary audio input.The T-Mice is a microphone that lies between the Helix and Traits portion of the ear (Figure 7); this allows the Cochlear Implant user to place a headphone at the natural position of the ear instead of directly at the Helix. Secondly, the auxiliary audio input is a microphone that directly connects to the music player via cable. Once the cable is hooked up to both vices, the microphone will pick up the electrical signal from the music player and temporarily block sound from the environment. FIGURE 7 Image courtesy of Midlines Some Cochlear Implants are manufactured with an easily-removed magnet.The Cochlear Implants magnet is attached to a small prosthetic device placed behind the ear during the Cochlear Implant surgery.
Removing this magnet is a necessity for Magnetic Resonance Imaging (MR.) because the static magnetic field of the MR. system is powerful enough to cause a demagnification of the magnet of the prosthetic device, rendering the Cochlear Implant useless. Magnet removal avoids the restraint of MR. procedures, a dangerous and possibly deadly restriction on the medical treatment of a Cochlear Implant user.What is the cost and lifespan of a Cochlear Implant? The average cost of a Cochlear Implant in the United States is $60,000 and ranges from 545,000-51 00,000 per person depending on the different features chosen. This cost includes diagnosis, surgery, hospitalizing, and rehabilitation. Receiving a Cochlear Implant usually requires only one surgery for a patient’s lifetime and is meant to last for the duration of the patient’s life.
How effective are Cochlear Implants? Cochlear Implants vary in effectiveness based on the person receiving it.For people who have been able to hear in the past and have lost their hearing, it is an effective way for them to hear and lip read. For individuals who have never been able to hear, the Cochlear Implant is not as effective, often due to nerve deterioration, similar to muscles weakening from lack of use.
What are the benefits of Cochlear Implants? People with Cochlear Implants are able to hear a variety of loud and soft sounds, such as a phone ringing, dog barking, or a light switch turning on. Additionally, people will be able to distinguish different sounds, such as identifying whether a speaker is a male or female.Furthermore, Cochlear Implants can help improve the users ability to lip read, however many users can hear without lip reading. Talking on the phone, watching TV, and listening to music are all possibilities for those with Cochlear Implants. What are the risks of Cochlear Implants? Patients are at risk for infections or health-related issues. The risk occurs during surgery and/or after surgery.
The most common risks occur during surgery; patients can suffer nerve damage, numbness around the ear, Meningitis, Cerebration’s fluid leakage, Periphery fluid leaks, or infection.Meningitis and some infections are contagious and they are easily transmitted into the body system if the surgical apparatuses and other substances in the operating room are not sterilized. Nerve damage and numbness can also occur when there is an operation error. Surgeons have a very small margin of space to operate on (depending on the patient, usually a two centimeter margin) and they have a high chance of bumping into the nerves.
Bumping into the nerves can cause nerve damage, leading to facial aralias, head numbness, sensory loss, taste abnormalities, and other health-related issues.Post-surgery risks include Tinnitus, vertigo, uncontrollable sound reflexes, and damage of the prosthetic device. Tinnitus, vertigo, and uncontrollable sound reflexes are health-related issues that occur when the Cochlear Implant interacts with the cochlea. Some cochleae are very sensitive when they interact with the electrode array. For instance, the cochlea may generate a health reaction when the electrode array signals a specific frequency sound (any. Where within the range from high frequency to low frequency).
The health reaction can result in twitching of the face, blinking, or other uncontrollable reflexes.In some cases, if a door closes (a high pitch) the patient may twitch or experience some other reaction as soon as the Cochlear Implant processes the high-pitch sound. Other post-surgery risks could result from damage to the Cochlear Implant itself. If the patient damages the receiver or stimulator, then he or she will have to undergo another surgery to replace the device.