The tool is a tool designed to improve hearing by making audible sounds for a person with hearing loss. Hearing aids are classified as medical devices in most countries, and are governed by their respective regulations. Small audio amplifiers such as PSAP or other plain sound reinforcement systems can not be sold as "hearing aids".
Early devices, such as ear trumpets or ear horns, are passive passive cones designed to collect sound energy and direct it into the ear canal. The modern device is a computerized electroacoustic system that changes the sound of the environment to make it audible, in accordance with audiometric and cognitive rules. Modern devices also utilize sophisticated digital signal processing to try and improve the user's voice and comfort clarity. Such signal processing includes feedback management, wide dynamic range compression, directionality, frequency reduction, and noise reduction.
Modern hearing aids require configuration to match the hearing loss, physical features, and lifestyle of the wearer. This process is called "fit" and is done by audiologist. The amount of benefits provided by hearing aids depends heavily on the quality of installation. Almost all hearing aids used in the US are digital hearing aids. Devices similar to hearing aids include the osseointegrated hearing prosthesis (formerly called bony hearing aids) and cochlear implants.
Video Hearing aid
Usage
Hearing aids are used for a variety of pathologies including sensorineural hearing loss, conductive hearing loss, and one-sided deafness. The hearing hearing candidate is usually determined by the audiologist, who will also match the device based on the nature and level of hearing loss being treated. The number of benefits that the hearing aid users experience is multi-factorial, depending on the type, severity, and etiology of hearing loss, technology and device instability, and on the motivation, personality, lifestyle, and overall health of the user.
Hearing aids can not really improve hearing loss; they are help to make the sound more audible. The most common form of hearing loss in which a hearing aid is sought is sensorineural, resulting from damage to the hair cells and synapses of the cochlear and hearing nerve. Sensoryineural hearing loss reduces sensitivity to sound, which can be helped by hearing aids with louder sounds. Other decreases in auditory perception caused by sensorineural hearing loss, such as abnormal spectral and temporal processing, and which may affect perceptions of speech negatively, are more difficult to compensate for the use of digital signal processing and in some cases may be exacerbated by the use of amplification. Conductive hearing losses, which do not involve damage to the cochlea, tend to be better treated with hearing aids; hearing aids can adequately amplify the sound to account for the attenuation caused by the conductive component. After the sound can reach the cochlea at normal or near normal levels, the cochlear and hearing nerve can transmit signals to the brain normally.
Common problems with fittings and use of hearing aids are the occlusion effects, the recruitment of loudspeakers, and the understanding of speech in noise. After common problems, feedback is generally now well controlled through the use of feedback management algorithms.
Maps Hearing aid
Candidates and acquisitions
There are several ways to evaluate how well the listener compensates for hearing loss. One approach is an audiometry that measures the subject's hearing level under laboratory conditions. The threshold of listening ability for various sounds and intensities is measured under various conditions. Although audiometric tests may attempt to mimic real-world conditions, each patient's own daily experience may be different. An alternative approach is self-reporting, in which patients report their experience with hearing aids.
Hearing aids can be represented by three dimensions:
- use of hearing aids
- voice recognition help
- benefits/satisfaction
The most reliable method for assessing correct hearing aid adjustments is through real ear measurements. Real ear measurements (or probe microphone measurements) are a characteristic assessment of the amplification of hearing aids near the eardrum using a silicon probe tube microphone.
Type
There are many types of hearing aids (also known as hearing aids), which vary in size, strength and circuits. Among the various sizes and models are:
Body-worn
The body tool used was the first portable electronic hearing aid, and was created by Harvey Fletcher while working at Bell Laboratories. Body aids consist of a case and an earmold, attached to a wire. This casing contains electronic amplifier components, controls and batteries, whereas earmold usually contains a miniature loudspeaker. This case is usually about the size of a pack of playing cards and carried in a pocket or in a belt. Without limitation on the size of smaller hearing devices, the design of the worn body help can provide great amplification and long battery life at lower costs. Body aids are still used in emerging markets because they are relatively cheap.
Behind the ear
Behind ear hearing aids is one of the two main classes of hearing aids - Behind the ear (BTE) and In the ear (ITE). Both classes are distinguished by where the hearing aids are used. The BTE hearing aid consists of a box that hangs behind a pinna. This casing is attached to the earmold or dome end with traditional tube, thin tube, or wire. Tube or wire from the superior-ventral part of pinna to concha, where ear print or dome tip inserts into an external auditory canal. Cases containing electronics, controls, batteries, and microphones. The loudspeaker, or receiver, can be placed in a chassis (traditional BTE) or at the earmold or dome end (receiver-in-the-channel or RIC).
BTE is generally capable of delivering more output and can therefore be indicated for more severe hearing loss. However, BTE is very versatile and can be used for almost any type of hearing loss. BTE is available in various sizes, ranging from small, "mini BTE," to larger ultra-power devices. Size usually depends on the level of output needed, the location of the receiver, and the presence or absence of telecoils. BTE is durable, easy to repair, and often has controls and battery doors that are more easily manipulated. BTE is also easily connected to hearing aids, such as FM systems and induction loops. BTE is generally used by children who need this type of hearing aid that is durable.
In the ear
In the ear tool (ITE) the device enters in the outer ear bowl (called concha). Being larger, this is easier to include and can store additional features. They are sometimes seen standing face to face with someone. ITE hearing instruments are tailor-made to fit the ears of each individual. They can be used in mild conditions up to some severe hearing loss. Feedback, whistling sounds caused by sound (especially high frequency sound) leak and amplify again, may be a problem for severe hearing loss. Some modern circuits are able to provide feedback or cancellation settings to help with this. Ventilation can also cause feedback. Ventilation is a tube placed to offer equalization of pressure. However, different styles and sizes of vents can be used to influence and prevent feedback. Traditionally, ITE has not been recommended for children because its suitability can not be easily modified as a cover for BTE, and thus aid should often be replaced when the child grows. However, there is a new ITE made of silicon type material that reduces the need for costly replacement. ITE hearing aids can be wirelessly connected to FM systems, for example with a body worn FM receiver with an induction loop that transmits audio signals from an inductive FM transmitter to a telecoil inside a hearing aid.
Mini in canal (MIC) or actually in canal (CIC) aids are generally invisible unless the audience is looking directly into the wearer's ear. This tool is intended for mild to moderate loss. CIC is usually not recommended for people with good low-frequency hearing, because the occlusion effect is much more noticeable. The complete hearing aid in the channel is very fitting in the ear. It was barely visible. Being small, it will not have a directional microphone, and its small battery will have a short life, and batteries and controls may be difficult to manage. His position on the ear prevents the sound of the wind and makes it easier to use the phone without feedback. The hearing aid in the channel is placed deep inside the ear canal. They are barely visible. Larger versions of these can have directional microphones. Being in a canal, they tend to cause feelings of disconnection. These models are easier to manipulate than the smaller inner-channel models but still have the disadvantages of being rather small.
Ear-ear hearing aids are usually more expensive than earphones behind the ears with the same function, as they are fitted into the patient's ears. In fitting, an audiologist takes a physical impression (mold) from the ear. This mold is scanned by a special CAD system, producing 3D models from the outer ear. During the modeling, the ventilation tube is inserted. Printed models of printed shell are printed using fast prototyping techniques such as stereolithography. Finally, the aid was collected and sent to an audiologist after quality inspection.
Hearing aid in an invisible channel
Earwax hearing instruments (IIC) that are not visible in the ear canal completely, leaving little or no trace of hearing aids installed. This is because it fits better in the channel than any other type, so it is not visible even when looking directly into the earplate (concha). A convenient fit is achieved because the relief shell is tailor-made for individual ear canals after taking the mold. This type of hearing aid is invisible using ventilation and deep placement in the ear canal to provide a more natural hearing experience. Unlike other types of hearing aids, IIC helps most ears not get clogged (clogged) by large plastic shells. This means that the sound can be collected more naturally with ear shape, and can walk into the ear canal as it is with unhelpful hearing. Depending on its size, some models allow the user to use the phone as a remote control to change memory and volume settings, rather than taking IIC to do this. IIC types are best suited for users up to middle age, but are not suitable for the elderly.
Long-wear wear aid
The old hearing instrument used is a non-surgical hearing aid in the ear canal by a hearing professional. The extended hearing wear tool is the first "invisible" hearing device. This device is used for 1-3 months at once without removal. They are made of soft materials designed for contours for each user and can be used by people with mild to moderate hearing loss. Their close proximity to ear drum results in improved direction and sound localization, reduced feedback, and increased high frequency. While traditional BTE or ITC hearing aids require insertion and removal every day, long wear aids are worn continuously and then replaced with new devices. Users can change the volume and settings without the help of a professional hearing. This device is very useful for active individuals because their design protects against moisture and ear wax and can be worn while exercising, bathing, etc. Because the placement of the device inside the ear canal makes them invisible to the observer, wear-resistant wear tools are very popular with those who are self-conscious about the aesthetics of BTE or ITC hearing aid models. Like other hearing devices, compatibility is based on a person's hearing loss, ear size and shape, medical condition, and lifestyle. Disadvantages include regular removal and device insertion when the battery is dead, the inability to enter underwater, the ear covering in the bath, and for some inconvenience due to insertion very deep in the ear canal, the only part of the body where the skin rests directly above the bone.
Bone anchored
Bone grooved hearing aid (BAHA) is a prosthetic hearing based on bone conduction that can be surgically implanted. This is an option for patients without external ear canal, when conventional hearing aids with ear prints can not be used. BAHA uses the skull as a sound track to travel to the inner ear. For people with conductive hearing loss, BAHA passes through the external auditory canal and middle ear, stimulating the function of the cochlea. For people with unilateral hearing loss, BAHA uses a skull to perform a voice from the side of the deaf to the side with a functioning cochlea.
Individuals under the age of two (five in the US) usually wear BAHA devices in Softband. This can be used since the age of one month because the baby tends to tolerate this arrangement very well. When the child's skull is thick enough, "post" titanium can be inserted into the skull with a small buffer that opens outside the skin. The BAHA sound processor resides on this buffer and transmits the sound vibration to the outer buffer of the titanium implant. The implant vibrates the inner skull and ear, which stimulates the inner ear nerve fibers, allowing hearing.
A simple surgical procedure is good for the surgeon, involving very little risk for an experienced ear surgeon. For the patient, slight discomfort and pain are reported. The patient may experience numbness in the area around the implant because the small superficial nerve in the skin is cut during the procedure. It often disappears after some time. There is no risk of further hearing loss due to surgery. One important feature of Baha is that, if a patient for any reason does not want to proceed with the setting, it takes the surgeon less than a minute to remove it. The Baha does not restrict the wearer from activities such as outdoor life, sports activities etc.
BAHA can be connected to the FM system by attaching a miniature FM receiver to it.
The two major brands produce BAHA today - original Cochlear inventors, and Oticon hearing instrument companies.
Eyeglass Tools
During the late 1950s to the 1970s, before ear aids became common (and in an era when thicker-popular glasses), people who wear glasses and hearing aids often choose the type of hearing instrument built into pieces of the temple from eyeglasses. However, the combination of glasses and hearing aids is not flexible: the frame style range is limited, and the user must use both hearing aids and glasses all at once or not using both. Today, people who use eyeglasses and hearing aids can use ear types, or rest the BTE neatly beside the sunglasses. There are still some special situations where hearing aids built into the eyeglass frames can be useful, such as when a person experiences hearing loss especially in one ear: the sound from the "bad" microphone can be sent through the frame to the side with better hearing.
This can also be achieved by using a CROS or bi-CROS hearing aid, which is now wireless in sending sound to the better side.
- the Spectacle hearing aid
This is generally imposed by people with hearing loss who prefer the cosmetic appeal of their hearing aids by attaching to their glasses or where the sound can not be passed in the normal way, through hearing aids, possibly due to blockage in the ear canal. lane or if the client is suffering from a persistent infection in the ear. The spectacle aids come in two forms, bone conduction spectacles and air conduction spectacles.
- Bone conduction glasses
The sound is transmitted through the attached receiver of the sunglasses arm mounted firmly behind the skull boney portion at the back of the ear, (the mastoid process) by means of pressure, applied to the sunglasses. The sound is passed from the receiver in the sunglasses to the inner ear (cochlea), through the bone. The process of transmitting sound through bones requires enormous strength. Bone conduction aids generally have a higher tone response that is worse and therefore best used for conductive hearing loss or where it is impractical to adapt a standard hearing aid.
- Air Conduction Glasses
Unlike bone conduction glasses, the sound is transmitted through hearing aids attached to the arm or sleeve of the glasses. When removing your glasses for cleaning, hearing aids are released at the same time. While there are native instances where spectacle aids are the preferred option, they may not always be the most practical choice.
- Directional glasses
These 'eyeglasses' combine the capabilities of the directional microphone: the four microphones on each side of the frame effectively function as two directional microphones, capable of distinguishing between the sound coming from the front and the sound coming from the user's side or back. This improves the signal-to-noise ratio by allowing for amplification of sound coming from the front, the direction in which the user is searching, and the active voice control for the sound coming from the sides or back. Only recently the required technology becomes small enough to be mounted in a frame of glasses. As a recent addition to the market, these new hearing aids are currently only available in the Netherlands and Belgium.
Stethoscope
This hearing aid is designed for medical practitioners with hearing impairments that use a stethoscope. Hearing aids are built into the stethoscope speakers, which amplify the sound.
Technology
The first hearing aids used the phone's carbon microphone and was introduced in 1896. The vacuum tube allows electronic amplification, but the initial version of a reinforced hearing aid is too heavy to carry. Miniaturization of vacuum tubes leads to a portable model, and after World War II, models that can be worn using miniature tubes. Transistors created in 1948 are particularly suitable for hearing aid applications because of their low power and small size; Hearing aids is the user's initial transistor. The development of integrated circuits enables further enhancement of the capabilities of wearable tools, including the application of digital signal processing techniques and program capabilities to the needs of each user.
Compatibility with phone
Hearing aids and phones are "compatible" when they are able to connect to each other in a way that produces clear, easy-to-understand sound. The term "compatibility" applies to all three types of phones (wired, wireless and mobile). There are two ways telephones and hearing aids can connect to each other:
- Acoustically: sound of the speakerphone is taken by the hearing aid microphone.
- Electromagnetically: the signal in the speakerphone is taken by a telecoil or T-coil hearing aid, a special loop of wire inside the hearing. help.
Note that the telecoil coupling has nothing to do with the radio signal on a cell phone or wirelessly: the audio signal taken by the telecoil is the weak electromagnetic field generated by the voice coil in the speakerphone as it pushes the speaker cone back and forth.
The electromagnetic (telecoil) mode is usually more effective than the acoustic method. This is mainly because the microphone is often turned off automatically when the hearing aid operates in telecoil mode, so the background noise is not reinforced. Because there is an electronic connection to the phone, his voice is more clear and distortion is less likely. But in order for this to work, the phone must be compatible with the hearing aid. More technically, the speaker phone must have a voice coil that produces a relatively strong electromagnetic field. Speakers with strong sound coils are more expensive and require more energy than the small ones used in many modern phones; phones with low-power speakers can not pair electromagnetically with telecoils in hearing aids, so the hearing aid must then switch to acoustic mode. In addition, many cell phones emit high-level electromagnetic sounds that create static sounds that are heard in hearing aids when telecoils are used. A solution that solves this problem in many phones is by installing a wired (not Bluetooth) headset into the phone; with a headset placed near a telephone hearing aid can be held far enough to attenuate static. Another method is to use "neckloop" (which is like a portable induction loop around the neck), and plug the neckloop directly into the standard audio jack (headphone jack) from the smartphone (or laptop, or stereo, etc.). Then, with a hearing aid telecoil turned on (usually a push button), the sound will travel directly from the phone, through the neckloop and into the hearing aid tape.
On March 21, 2007, the Telecommunications Industry Association issued a TIA-1083 standard, which gave manufacturers cordless phones the ability to test their products for compatibility with most hearing aids that have a T-Coil magnet coupling mode. With this test, digital cordless phone manufacturers will be able to tell consumers about which products will work with their hearing aids.
The American National Standards Institute (ANSI) has a ranking scale for compatibility between hearing aids and telephones:
- When operating in acoustic mode ( M icrophone), it ranks from M1 (worst) to M4 (best).
- When operating in electromagnetic mode ( T elecoil), the rating is from T1 (worst) to T4 (best).
The best rating is M4/T4 which means the phone works fine in both modes. Devices with ratings below M3 are not satisfactory for people with hearing aids.
Computer programs that enable the creation of hearing aids using PCs, tablets, or smartphones are now gaining in popularity. Modern mobile devices have all the components needed to implement this: hardware (microphones and regular headphones can be used) and high-performance microprocessors that carry digital voice processing according to the given algorithm. The application configuration is performed by the users themselves according to the features of each of their hearing capabilities. The computing power of modern mobile devices is enough to produce the best sound quality. This, coupled with software application settings (for example, the selection of profiles according to a healthy environment) provides the convenience and ease of use. Compared to digital hearing aids, mobile apps have the following advantages:
- ease of use (no need to use additional devices, batteries, and so on.);
- high usage convenience;
- complete see-through (smartphones not associated with hearing aids);
- user friendly software settings interface;
- High sampling frequency (44.1 kHz) provides excellent sound quality;
- Toggle quickly between your external headset and your phone's microphone;
- acoustic gain up to 30 dB (with standard headset);
- low delay in audio processing (from 6.3 to 15.7 ms - depending on mobile device model);
- No need to get used, when changing mobile devices;
- No settings are lost when switching from one gadget to another and back again;
- High battery duration;
- free app distribution.
It should be clearly understood that "hearing aid" apps for smartphones/tablets can not be considered as complete replacements of digital hearing aids, because the latter:
- is a medical device (subject to relevant testing and certification procedures);
- is designed for use with a doctor's prescription;
- is adjusted using an audiometric procedure.
The functionality of a hearing aid application may involve a hearing test (in situ audiometry) as well. However, the test results are only used to adjust the device to be comfortable working with the application. Hearing testing procedures in any way can not claim to replace an audiometric test performed by a medical specialist, so it can not be the basis for the diagnosis.
- Apps such as Oticon ON for specific iOS (Apple) and Android devices can help locate missing/misplaced hearing aids.
Wireless
Recent hearing aids include wireless hearing aids. One hearing aid can transmit to the other side so pressing the program buttons one help simultaneously will change the other help, so both help change the background settings simultaneously. FM listeners systems now appear with integrated wireless receivers with the use of hearing aids. Separate wireless microphones may be provided to couples for use in restaurants, in cars, during leisure time, in shopping centers, in lectures, or during religious functions. Sound is transmitted wirelessly to the hearing aid eliminating the effects of distance and background noise. The FM system has been proven to provide the best speech understanding in the noise of all available technologies. FM systems can also be connected to a TV or stereo.
2.4 gigahertz Bluetooth connectivity is the latest innovation in wireless interfaces for hearing aids to audio sources such as TV tapes or Bluetooth enabled phones. Today's hearing aids generally do not stream directly via Bluetooth but via a secondary streaming device (usually used around the neck or in a pocket), this bluetooth allows the secondary device to then wirelessly stream to the hearing aid but can only do it over short distances. This technology can be applied to ready-made devices (BTE, Mini BTE, RIE, etc.) or custom-made devices that fit directly into the ear.
In developed countries the FM system is regarded as the foundation in the treatment of hearing loss in children. More and more adults are discovering the benefits of wireless FM systems as well, especially since transmitters with different microphone settings and Bluetooth for wireless mobile phone communications are available.
Many theaters and lecture halls are now equipped with a helpful hearing system that sends live sound from the stage; members of the audience can borrow the appropriate receiver and hear the program without background noise. In some theaters and churches, FM transmitters are available that work with personal FM receivers of hearing aids.
Directional microphone
Most older hearing aids have only omnidirectional microphones. Omnidirectional microphone amplifies the same sound from all directions. Instead, the directional microphone amplifies sound from one direction more than the sound from the other direction. This means that the sound coming from the direction of the system is directed towards being amplified more than the sound coming from the other direction. If the desired speech arrives from the steering direction and the noise comes from different directions, then compared to omnidirectional microphone, the directional microphone gives better signal to noise ratio. Increasing the signal-to-noise ratio improves the understanding of speech in noise. Directional microphones have been found to be the second best method to improve signal-to-noise ratio (the best method is the FM system, which places the microphone near the spokes of the desired speaker).
Many hearing aids now have omnidirectional and directional microphone modes. This is because the wearer may not need or want the noise-reducing properties of the pointing microphone in a given situation. Normally, omnidirectional microphone mode is used in quiet hearing situations (eg living room) whereas directional microphones are used in noisy hearing situations (eg restaurants). Microphone mode is usually selected manually by the user. Some hearing aids automatically switch the microphone mode.
Adaptive directional microphones automatically change the direction of amplification or maximum rejection (to reduce disturbing targeted sound sources). The direction of amplification or rejection varies by the hearing aid processor. The processor tries to provide maximum amplification toward the desired speech signal source or rejection towards the disturbing signal source. Unless the user manually switches temporarily to the "restaurant program, forward only" program, the adaptive focus microphone often reinforces the conversation of other speakers in a cocktail party environment, such as a restaurant or coffee shop. The presence of a double speech signal makes it difficult for the processor to select the desired speech signal correctly. Another disadvantage is that some sounds often contain characteristics similar to speech, making it difficult for a hearing aid processor to distinguish noise from noise. Despite the drawbacks, the adaptive directional microphone can provide better sound recognition in noise
FM systems have been found to provide a better signal to noise ratio even at larger speaker-to-talker ranges under simulated testing conditions.
Telecoil
Telecoils or T-coils (from "Telephone Coils") are small devices installed in hearing aids or cochlear implants. An Audio induction loop produces an electromagnetic field that can be detected by T-coil, allowing the audio source to connect directly to the hearing aid. T-coil is intended to help the user filter out background noise. They can be used with telephones, FM systems (with neck loops), and induction loop systems (also called "auditory loops") that transmit sound to hearing aids from public address systems and TV. In the UK and Nordic countries, hearing is widely used in churches, shops, railway stations, and other public places. In the US, telecoils and hearing loops are gradually becoming more common. Audio induction loops, telecoils and hearing gradually become more common also in Slovenia.
A T-coil consists of a metal core (or rod) in which the ultra-fine wire is rolled up. The T-coil is also called the induction coil because when the coil is placed in the magnetic field, electric current back and forth is induced in the wire (Ross, 2002b; Ross, 2004). T-coil detects magnetic energy and transfers (converts) to electrical energy. In the United States, the TIA-1083 standard of the Telecommunications Industry Association, establishes how analog handsets can interact with telecoil devices, to ensure optimum performance.
Although T-coils are effectively broadband recipients, the disorder usually occurs in most hearing situations. Interference can manifest as a buzzing sound, which varies in volume depending on the distance of the wearer from the source. The source is an electromagnetic field, such as a CRT computer monitor, older fluorescent lamps, some dimmer switches, many household electrical appliances and airplanes.
The states of Florida and Arizona have passed laws requiring hearing professionals to inform patients about the usefulness of telecoils.
Rules affecting use
In the United States, the Hearing Instrument Compatibility Act of 1988 requires that the Federal Communications Commission (FCC) ensure that all phones manufactured or imported for use in the United States after August 1989, and all "essential" phones, compatible (through the use of telecoils).
An "essential" phone is defined as "coin-operated phones, phones provided for emergency use, and other calls that are often required for use by people using such hearing aids." This may include telephones at work, phones in limited settings (such as hospitals and nursing homes), and phones in hotel and motel rooms. Secure phones, as well as phones used with cellular and private radio services, are excluded from the HAC Act. "Safe" phones are defined as "phones approved by the Government of the U.S. for the transmission of secret or sensitive voice communications."
In 2003, the FCC adopted the rules to make digital cordless phones compatible with hearing aids and cochlear implants. Although analog wireless phones do not normally cause interference with hearing aids or cochlear implants, digital cordless phones are often made because of the electromagnetic energy emitted by mobile antennas, backlights, or other components. The FCC has set a schedule for the development and sales of digital wireless phones that are compatible with hearing aids. These efforts promise to increase the number of digital wireless phones that are compatible with hearing aids. The older generation of both cordless and wireless phones use analog technology.
Direct audio input
Direct audio input (DAI) allows the hearing aid to directly connect to an external audio source such as a CD player or hearing aid (ALD). In accordance with its nature, DAI is susceptible to far less electromagnetic interference, and produces better quality audio signals than using T-coils with standard headphones. Audio Boot is a type of device that can be used to facilitate DAI.
Processing
Every electronic hearing aid has at least a microphone, a loudspeaker (commonly called a receiver), a battery, and an electronic circuit. Electronic circuits vary between devices, although both have the same style. Circuits are divided into three categories based on the type of audio processing (analog or digital) and the type of control circuitry (adjustable or programmable). Hearing aids generally do not contain processors strong enough to process complex signal algorithms for localization of sound sources.
Analog
Analog audio may have:
-
- Customizable controls: Analog audio circuits with customizable electronic components. Professional hearing determines the acquisition and other specifications required for the wearer, and then adjusts the analog component either with a small control on the hearing aid itself or by having the laboratory build a hearing aid to meet those specifications. After the resulting audio adjustment does not change further, in addition to the overall loudness that the user adjusts to the volume control. This type of circuit is generally most inflexible. The first practical electronic hearing aids with customizable analog audio circuits are based on US Patent 2,017,358, "Hearing and Reinforcement Aids" by Samual Gordon Taylor, filed in 1932.
- Programmable controls: Analog audio circuits but with additional electronic control circuits that can be programmed by audiologists, often with more than one program. Electronic control circuits can be repaired during manufacture or in some cases, a hearing professional can use an external computer that is temporarily connected to a hearing aid to program additional control circuits. Users can change the program to different hearing environments by pressing the buttons either on the device itself or on the remote control or in some cases additional control circuits operate automatically. This type of circuit is generally more flexible than simple adjustable controls. The first hearing aids with analog audio circuits and automatic digital electronic control circuits are based on US Pat. No. 4,025,721, "The methods and means to filter the adaptive near-stationary noise from speech" by D Graupe, GD Causey, filed in 1975. Electronics This digital control circuit is used to identify and automatically reduce noise in individual frequency channels of analogue audio circuits and is known as Zeta Noise Blocker.
Digital
Digital audio, programmable controls: Both audio circuits and digital control circuits are fully digital. Hearing aid hearing aid programs with external computers while connected to the device and can customize all processing characteristics individually. The fully digital circuit enables the implementation of many additional features that are not possible with analog circuits, can be used in all styles of hearing aids and are the most flexible; for example, digital hearing aids can be programmed to amplify certain frequencies more than others, and can provide better sound quality than analogue hearing aids. Digital hearing aids are fully programmable with programs that the user can request, or that operate automatically and adaptively. These programs reduce the acoustic feedback (whistling), reduce background noise, detect and automatically accommodate different hearing environments (hard vs. soft, speech vs. music, quiet vs noisy, etc.), control additional components such as multiple microphones to increase spatial hearing, frequency transpose (high frequency shifts that the user can not hear to a low frequency area where hearing might be better), and apply many other features. The full digital circuitry also allows control of wireless transmission capability for audio and control circuits. Control signals in a hearing aid in one ear can be wirelessly transferred to a control circuit in the opposite ear hearing aid to ensure that the audio in both ears can be matched directly or that the audio contains a deliberate difference that mimics differences under normal conditions. binaural hearing to preserve spatial hearing ability. Audio signals can be sent wirelessly to and from external devices through a separate module, often a small device worn like a pendant and commonly called "streamer", allowing wireless connections to other external devices. This capability enables the use of mobile phones, personal music players, microphones remotely, and other devices optimally. With the addition of voice recognition and internet capabilities in mobile phones, the wearer has optimal communication skills in more situations than with hearing aids only. This list includes voice dialing enabled, voice-activated software applications either in the phone or on the internet, reception of audio signals from databases in the phone or on the internet, or audio signals from television or from a global positioning system. The first practical, applicable, and fully customized digital hearing aids by Maynard Engebretson, Robert E Morley, Jr. and Gerald R Popelka. Their work resulted in US Pat. No. 4,548,082, "Hearing Aids, Signaling Equipment, Systems to Compensate Hearing Loss, and Methods" by A Maynard Engebretson, Robert E Morley, Jr. and Gerald R Popelka, filed in 1984. This patent forms the basis of all the next complete digital hearing aid from all manufacturers, including those currently produced.
Signal processing is performed by the microprocessor in real time and taking into account individual user preferences (eg, improving bass for better speech perception in noisy environments, or high frequency selective amplification for people with reduced sensitivity to this range). The microprocessor automatically analyzes the properties of external background noise and adjusts signal processing to specific conditions (as well as changes, for example, when the user exits the building).
Difference between digital and analog hearing aids
Analogue hearing aids make the sound louder than all the sounds captured by the microphone. For example, speech and ambient sounds will be made louder. On the other hand, digital hearing aid technology (DHA) processes sound using digital technology. Before transmitting sound to speakers, DHA microprocessors process digital signals received by microphones according to mathematical algorithms. This makes it possible to make sounds louder than a certain frequency according to individual user settings (personal audiogram), and automatically adjust DHA jobs to various environments (noisy streets, quiet spaces, concert halls, etc.).
For users with varying degrees of hearing loss, it is difficult to see the entire range of external sound frequencies. DHA with multi-channel digital processing allows the user to "compose" the output sound by installing the entire spectrum of input signals into it. It provides users with limited hearing ability the opportunity to see the entire range of ambient sounds, despite the personal difficulty of perception of certain frequencies. In addition, even within the "narrow" range of DHA microprocessors it is able to emphasize the desired sound (eg speech), weaken unwanted, high, unwanted sounds at the same time.
The advantages of digital aids include: According to DHA research has a number of significant advantages (compared with analog hearing aids):
- Digital signal processing helps reduce noise and distinguish speech signals from the overall spectrum of sounds that facilitate speech perception.
- Reduce background noise levels improves user convenience (especially in noisy environments, eg on the road).
- The flexibility setting provides selective amplification of specific frequencies (according to the personal characteristics of impaired hearing).
- Effective acoustic feedback reduction.
- Possible use of directional microphones, which greatly facilitates the perception of sound in a particular environment, for example when speaking face-to-face, or listening to a distant teacher.
- Extended frequency range (ability to listen to large amounts of sound).
- Adaptive adaption "self-study" that facilitates the use of the device for a number of users.
- Possible device connect (phone, smart phone, etc.).
- In general, maximum voice purification is sent to the user.
The advantages of DHA are confirmed by a number of studies, related to the comparative analysis of first and second generation digital hearing aids and analogue hearing aids.
Difference between PSAP and digital hearing aid
Personal Sound Amplification Products (PSAP abbreviated) are classified by the FDA as "personal voice amplification devices." This compact electronic device is designed for people without hearing impairment. Unlike hearing aids (classified by the FDA as a means to compensate for hearing loss) the use of PSAP does not require a doctor's prescription. The device is used by hunters, naturalists (for animal or bird audio observations), ordinary people (for example, to increase the volume of TV in a quiet room), etc. The PSAP model is very different in terms of price and function. Some devices only amplify the sound. Others contain directional microphones, equalizer to adjust audio signal strengthening and noise filters.
History
The first hearing instrument is the ear trumpet, and was created in the 17th century. Some of the first hearing aids are external hearing aids. The external hearing instrument directs the sound in front of the ear and blocks all other sounds. The equipment will fit behind or in the ear.
The movement toward modern hearing aids began with the making of the telephone, and the first hearing aid, "akouphone", was invented around 1895 by Miller Reese Hutchison. At the end of the 20th century, digital hearing aids were commercially available.
The discovery of a carbon microphone, transmitter, digital signal processing chip or DSP, and the development of computer technology help transform hearing aids into their current form.
History of digital help
The history of DHA can be divided into three stages. First stage - widespread use of computer simulations for system analysis and algorithms for audio processing. The work was done with the help of a "big" computer at the time. Although they can not claim to be real hearing aids (their performance is not enough for real time audio processing - not to mention the size), they do successful research from various hardware and algorithm series to process audio signals. The BLODI software package (abbreviation Block from the Compilation Diagram) developed by Kelly, Lockbaum and Vysotskiy in 1961 was allowed to simulate any sound system provided in the form of block diagrams. With his help, special phones for users with hearing loss have been created. In 1967, Harry Levitt used BLODI to simulate hearing aids in a digital computer.
Nearly ten years later the second step was taken - the manufacture of "quasi-digital" hearing aids, in which analog components and programmable digital modules were combined into a single container. In this device the digital controller not only controls the analog components (amplifiers, filters, and signal barriers), but can be programmed by connecting an external computer (in the laboratory - with hearing aid medical equipment).
The concept of quasi-digital devices is very successful from a practical point of view because of its low power consumption and compact size. At that time, low-power analogue amplifier technology developed very well - in contrast to semiconductor chips needed for "real" digital cameras. The combination of high-performance analogue components and digital signal processing capabilities has made the module of creating successful parts of production.
This type of hearing aid developed by Etymonic Design. Moments later, Mangold and Lane created programmable multi-channel hearing aids. A similar approach is applied by Sama, Graupe with co-authors to develop adaptive noise filters on single crystals. This relatively small chip has a low power consumption and is suitable in the case of ordinary BTE hearing or ITC hearing aids.
The third stage of development is the emergence of "real" digital hearing aids. In DHA all stages of voice processing are performed in binary form. To do this, the external sound from the first microphone is converted to binary code, and after conversion the transformation is done (to the analog signal sent by the ear speaker in the form of sound). The first "original" DHA was a model developed by Graup in 1970 on the basis of an 8080 microprocessor, which replaced analog components (amplifiers, limiter and filters). Possible programmable processors make the device fit in, opening up prospects for advanced signal processing techniques, noise reduction, etc. Although the 8080 processor is relatively slow and large in size.
Further DHA development is associated with the creation of microprocessors with parallel processing of the data array. As a result, significant calculation time decreases provide an opportunity to process audio signals in real time. The small size of microchips (in 1987) made it possible to make concise hearing aids not beyond their analog "precursor" dimensions on their basis. However, for the ITC help this processor has not been quite compact. In all other respects, the "full" DHA of that period is very similar to the modern model.
Rule
ireland
Like most Irish health care systems, the provision of hearing aids is a mixture of public and private.
Hearing aids are provided by the State for children, OAPs and for those whose income is below or under the State Pension. Ireland's hearing aid is very poor; people often have to wait two years to make an appointment.
It is estimated that the total cost for the State, supplying one hearing aid, exceeds EUR2,000.
Hearing aids are also available privately, and there is grant aid available for the insured worker. Currently for the fiscal year ending in 2016, grants reach a maximum of EUR500 per ear.
Irish taxpayers can also claim tax relief, at a standard level, because hearing aids are recognized as medical devices.
Hearing aids in the Republic of Ireland are excluded from VAT.
Hearing aid providers in Ireland mostly belong to the Hearings of the Irish Community Audience.
United States
Hearing Aids is a medical device regulated by Class I under Federal Food and Drug Administration (FDA) regulations. The 1976 law explicitly prohibits any state requirement that "differs from, or in addition to, any applicable terms" for regulated medical devices (which include hearing aids) relating "to the safety and effectiveness of the device." Inconsistent state regulations are prioritized under federal law. In the late 1970s, the FDA established federal regulations governing the sale of hearing aids, and handled requests by state authorities for the exclusion of federal preemption, granting some and denying others.
Cost
Some industrialized countries provide free or large discounted hearing aids through their publicly funded health care systems.
Australia
The Australian Department of Health and Aging provides qualified Australians and residents with free hearing aids, although recipients can pay a "refill" fee if they want to upgrade to hearing aids with more or better features. Hearing of this hearing aid and regular battery supplies are also provided, with a small annual maintenance fee payment.
Canada
In Canada, health care is the responsibility of the province. In the province of Ontario, the price of hearing aids is partially replaced through a Tool Kit of the Ministry of Health and Long Term Care, up to $ 500 for each hearing aid. Like an eye promise, an audiological promise is no longer covered through the provincial public health plan. Audiometric tests can still be obtained easily, often for free, at a private sector hearing clinic and some ear doctors offices, nose and throat. Hearing Aids can be covered to some extent by private insurance or in some cases through government programs such as Veterans Affairs Canada or Safety & amp; Board of Insurance.
Iceland
Social Insurance pays a one-time fee of ISK 30,000 for all types of hearing aids. However, the rules are complex and require both ears to have significant hearing loss to qualify for replacement. BTE hearing aids range from ISK 60,000 to ISK 300,000.
India
In India, all hearing aids are easily available. Under state and state government health services, the poor can often avail themselves of free hearing aids. However, market prices vary for others and can range from Rs 1,000 to Rs 275,000 per ear.
United Kingdom
From 2000 to 2005 the Ministry of Health worked with Action on Hearing Loss (later called RNID) to improve the quality of NHS hearing aids so that every NHS audiology department in the UK was a digital hearing aid fitting in March 2005. In 2003 More than 175,000 digital NHS Help has been installed for 125,000 people. Private companies are recruited to increase capacity, and two are appointed - David Ormerod Hearing Center, partly owned by Alliance Boots and Ultravox Group, a subsidiary of Amplifon.
In the United Kingdom, the NHS provides digital BTE hearing aids for NHS patients, with long-term, free loans. In addition to the Bahas (hearing instrument bone), where special is required, BTE is usually the only style available. Private purchases may be required if the user wants a different style. Battery is free.
In 2014, the Clinical Commissioning Group in North Staffordshire is considering a proposal to end the provision of free hearing aids for adults with mild to moderate hearing loss, which currently cost 1.2 million pounds per year. Action on Hearing Loss mobilizes campaigns against proposals.
In June 2018, the National Institute for Health and Nursing Excellence produced a new guide saying that hearing aids should be offered at the first opportunity after hearing loss is detected rather than waiting for an arbitrary hearing loss limit to be achieved.
United States
Most private healthcare providers in the United States do not provide coverage for hearing aids, so all expenses are usually borne by the recipient. The cost of a hearing aid can vary between $ 500 and $ 6,000 or more, depending on the level of technology and whether the doctor incorporates the cost of installation into the cost of a hearing aid. Even if adults have hearing impairments that substantially restrict major life activities, some state-run vocational rehabilitation programs may provide full financial assistance. Severe and profound hearing loss often falls into the "substantially limited" category. Cheaper hearing aids can be found on the internet or mail order catalogs, but mostly in the range of less than $ 200 tends to amplify low-frequency background noise, making it harder to hear human voices.
Military Veterans who receive VA medical care are eligible for hearing aids based on medical needs. The Veterans Administration pays the entire cost of testing and hearing aids to qualified military veterans. VA's main medical facilities provide comprehensive diagnostic and audiological services.
The cost of a hearing aid is a tax-deductible medical cost for those who itemize medical deductions.
Research involving more than 40,000 US households shows a convincing correlation between the rate of hearing loss and the reduction of personal income. According to the same study, the trend was not observed in nearly 100% of households using DHA.
Battery
Although there are some examples that hearing aids use rechargeable batteries or long-lasting disposable batteries, most modern hearing aids use one of five standard zinc-air battery cell buttons. (Older hearing aids often use mercury battery cells, but these cells have been banned in most countries today.) The types of modern hearing aid button cells are usually referred to by their regular number names or color packs.
They are usually loaded into hearing aids through a rotating battery door, with the flat side (box) as the positive terminal (cathode) and the rounded side as the negative terminal (anode).
All these batteries operate from 1.35 to 1.45 volts.
The type of battery used by a particular hearing aid depends on the allowed physical size and the desired battery life, which in turn is determined by the drawing power of the hearing aid. Typical battery life runs between 1 and 14 days (assuming 16 hours per day).
See also
- Cochlear implant
- Ear trumpet
- Electronic nose
- El Deafo (Cece Bell novel)
- Orkney Wireless Museum - has a 1930s Ardent hearing instrument in its collection
- Sonotone 1010 - the first electronic hearing aid to use transistor
- Spatial loss of hearing
References
External links
- Information from the National Institutes of Health (NIH)
- The American Hearing Research Foundation funded research to hear and aim to help educate the public in the United States.
- National Institute of Deaf Kingdom Information and resources on hearing loss.
- Historical
- Incognito Intrins: Hidden Hearing Aids from the 19th and 20th Century
Source of the article : Wikipedia
0 Comments