Memorial Hearing Center
644 N 2nd St, Springfield
hospital doctor health
Kerr Hearing Aid Center
2631 Chatham Rd, Springfield
store health point of interest
Connect Hearing
2425 W Iles Ave Ste 102, Springfield
doctor store health
Sears Hearing Aid Service Center by Miracle-Ear
2790 Woodlawn Rd, Lincoln
store health point of interest

More About Hearing Aid Services from Wikipedia

Devices similar to hearing aids include the osseointegrated auditory prosthesis (formerly called the bone-anchored hearing aid) and cochlear implant.
Real ear measurements (or probe microphone measurements) are an assessment of the characteristics of hearing aid amplification near the ear drum using a silicone probe tube microphone.


Types


There are many types of hearing aids (also known as hearing instruments), which vary in size, Electric power and circuitry.
Among the different sizes and models are:



File:Vintage Zenith Radionic 3-Vacuum Tube (Body) Hearing Aid, Model-A3A, Pastel Coralite Case, Bone-Air, Original Cost = 50.00 USD, Circa 1944 (10840966755).jpg|Vacuum tube hearing aid, circa 1944
File:Vintage Telex Transistor (Body) Hearing Aid, Model 70A, Made in the USA (12483173304).jpg|Transistor body-worn hearing aid.
File:BTEhearingaids.png|Pair of BTE hearing aids with earmolds.
File:Hinter-Ohr-Hörgeräte.JPG|Receiver-in-the-Canal hearing aids
File:HearingAid ITE.png|In-the-Ear Hearing Aid
File:Hearing aid cic.jpg|In-the-canal hearing aid
File:Lyric - Ear.jpg|Completely in the canal hearing aids
File:Baha user sound processor behind ear.PNG|Woman wearing a bone anchored hearing aid

Body-worn

Body worn aids were the first portable electronic hearing aids, and were invented by Harvey Fletcher while working at Bell Laboratories. Body aids consist of a case and an earmold, attached by a wire. The case contains the electronic amplifier components, controls and Battery (electricity) while the earmold typically contains a miniature loudspeaker. The case is typically about the size of a pack of playing cards and is carried in a pocket or on a belt.
Without the size constraints of smaller hearing devices, body worn aid designs can provide large amplification and long battery life at a lower cost. Body aids are still used in emerging markets because of their relatively low cost.


Behind the ear

Behind the ear hearing aids are one of two major classes of hearing aids - Behind the ear (BTE) and In the ear (ITE). These two classes are distinguished by where the hearing aid is worn. BTE hearing aids consist of a case which hangs behind the Auricle (anatomy) The case is attached to an earmold or dome tip by a traditional tube, slim tube, or wire. The tube or wire courses from the superior-ventral portion of the pinna to the concha, where the ear mold or dome tip inserts into the Ear canal. The case contains the electronics, controls, battery, and microphone(s).The loudspeaker, or receiver, may be housed in the case (traditional BTE) or in the earmold or dome tip (receiver-in-the-canal, or RIC).


BTEs are generally capable of providing more output and may therefore be indicated for more severe degrees of hearing loss. However, BTEs are very versatile and can be used for nearly any kind of hearing loss. BTEs come in a variety of sizes, ranging from a small, "mini BTE," to larger, ultra-power devices. Size typically depends on the output level needed, the location of the receiver, and the presence or absence of a telecoil. BTEs are durable, easy to repair, and often have controls and battery doors that are easier to manipulate. BTEs are also easily connected to assistive listening devices, such as Frequency modulation systems and induction loops. BTEs are commonly worn by children who need a durable type of hearing aid.


In the ear

In the ear aids (ITE) devices fit in the outer ear bowl (called the Pinna (anatomy)). Being larger, these are easier to insert and can hold extra features. They are sometimes visible when standing face to face with someone. ITE hearing aids are custom made to fit each individual's ear. They can be used in mild to some severe hearing losses. Audio feedback, a squealing/whistling caused by sound (particularly high frequency sound) leaking and being amplified again, may be a problem for severe hearing losses. Some modern circuits are able to provide feedback regulation or cancellation to assist with this.
Venting may also cause feedback. A wikt:vent is a tube primarily placed to offer pressure equalization. However, different vent styles and sizes can be used to influence and prevent feedback.Sickel, K. (13 September 2007) [http://www5.informatik.uni-erlangen.de/Forschung/Publikationen/2007/Sickel07-SPS.pdf Shortest Path Search with Constraints on Surface Models of In-ear Hearing Aids] ''



  1. IWK, Internationales Wissenschaftliches Kolloquium'' (Computer science meets automation Ilmenau 10.) Vol. 2 Ilmenau : TU Ilmenau Universitätsbibliothek 2007, pp. 221–226
    Traditionally, ITEs have not been recommended for young children because their fit could not be as easily modified as the earmold for a BTE, and thus the aid had to be replaced frequently as the child grew. However, there are new ITEs made from a silicone type material that mitigates the need for costly replacements.
    ITE hearing aids can be connected wirelessly to FM systems, for instance with a body-worn FM receiver with induction neck-loop which transmits the audio signal from the FM transmitter inductively to the telecoil inside the hearing instrument.


Mini in canal (MIC) or completely in canal (CIC) aids are generally not visible unless the viewer looks directly into the wearer's ear.Eisenberg, Anne (24 September 2005) [https://www.nytimes.com/2006/09/24/business/yourmoney/24novel.html?ex=1164517200&en=dba8306ee44bce99&ei=5070 The Hearing Aid as Fashion Statement] . ''NY Times''.Dybala, Paul (6 March 2006) [http://www.audiologyonline.com/articles/article_detail.asp?article_id=1542 ELVAS Sightings – Hearing Aid or Headset] . AudiologyOnline.com. These aids are intended for mild to moderately severe losses. CICs are usually not recommended for people with good low-frequency hearing, as the occlusion effect is much more noticeable.Ross, Mark (January 2004) [http://www.hearingresearch.org/ross/hearing_loss/the_occlusion_effect.php The "Occlusion Effect" – What it is, and What to Do About it] , hearingresearch.org. Completely-in-the-canal hearing aids fit tightly deep in the ear. It barely visible. Being small, it will not have a directional microphone, and its small batteries will have a short life, and the batteries and controls may be difficult to manage. Its position in the ear prevents wind noise and makes it easier to use phones without feedback. In-the-canal hearing aids are placed deep in the ear canal. They are barely visible. Larger versions of these can have directional microphones. Being in the canal, they are less likely to cause a plugged feeling. These models are easier to manipulate than the smaller completely in-the-canal models but still have the drawbacks of being rather small.


In-the-ear hearing aids are typically more expensive than behind-the-ear counterparts of equal functionality, because they are custom fitted to the patient's ear.
In fitting, an audiologist takes a physical impression (Polyvinyl siloxane) of the ear.
The mold is scanned by a specialized Computer-aided design system, resulting in a 3D model of the outer ear.
During modeling, the venting tube is inserted.
The digitally modeled ''shell'' is printed using a rapid prototyping technique such as stereolithography.
Finally, the aid is assembled and shipped to the audiologist after a quality check.Sickel, K. et al. (2009) [http://www5.informatik.uni-erlangen.de/Forschung/Publikationen/2009/Sickel09-SMO.pdf "Semi-Automatic Manufacturing of Customized Hearing Aids Using a Feature Driven Rule-based Framework"]. ''Proceedings of the Vision, Modeling, and Visualization Workshop 2009'' (Braunschweig, Germany 16–18 November 2009), pp. 305–312


Invisible in-canal hearing aids

Invisible in canal hearing aids (IIC) style of hearing aids fits inside the ear canal completely, leaving little to no trace of an installed hearing aid visible. This is because it fits deeper in the canal than other types, so that it is out of view even when looking directly into the ear bowl (concha). A comfortable fit is achieved because the shell of the aid is custom-made to the individual ear canal after taking a mould.
Invisible hearing aid types use venting and their deep placement in the ear canal to give a more natural experience of hearing. Unlike other hearing aid types, with the IIC aid the majority of the ear is not blocked (occluded) by a large plastic shell. This means that sound can be collected more naturally by the shape of the ear, and can travel down into the ear canal as it would with unassisted hearing. Depending on their size, some models allow the wearer to use a mobile phone as a remote control to alter memory and volume settings, instead of taking the IIC out to do this. IIC types are most suitable for users up to middle age, but are not suitable for more elderly people.
A bone anchored hearing aid (BAHA) is an auditory system prosthetic based on bone conduction which can be surgically Implant (medicine). It is an option for patients without external ear canals, when conventional hearing aids with a mould in the ear cannot be used. The BAHA uses the Human skull as a pathway for sound to travel to the inner ear. For people with conductive hearing loss, the BAHA bypasses the external auditory canal and middle ear, stimulating the functioning cochlea. For people with unilateral hearing loss, the BAHA uses the skull to conduct the sound from the deaf side to the side with the functioning cochlea.


Individuals under the age of two (five in the USA) typically wear the BAHA device on a Softband. This can be worn from the age of one month as babies tend to tolerate this arrangement very well. When the child's skull bone is sufficiently thick, a titanium "post" can be surgically embedded into the skull with a small abutment exposed outside the skin. The BAHA sound processor sits on this abutment and Transmission (telecommunications) sound vibrations to the external abutment of the titanium implant. The implant vibrates the skull and inner ear, which stimulate the nerve fibers of the inner ear, allowing hearing.


The surgical procedure is simple both for the surgeon, involving very few risks for the experienced ear surgeon. For the patient, minimal discomfort and pain is reported. Patients may experience numbness of the area around the implant as small superficial nerves in the skin are sectioned during the procedure. This often disappears after some time. There is no risk of further hearing loss due to the surgery. One important feature of the Baha is that, if a patient for whatever reason does not want to continue with the arrangement, it takes the surgeon less than a minute to remove it. The Baha does not restrict the wearer from any activities such as outdoor life, sporting activities etc.


A BAHA can be connected to an FM system by attaching a miniaturized FM receiver to it.


Two main brands manufacture BAHAs today – the original inventors Cochlear Baha, and the hearing aid company Oticon.


Eyeglass aids

During the late 1950s through 1970s, before in-the-ear aids became common (and in an era when thick-rimmed eyeglasses were popular), people who wore both glasses and hearing aids frequently chose a type of hearing aid that was built into the
Temple (anatomy) pieces of the spectacles. However, the combination of glasses and hearing aids was inflexible: the range of frame styles was limited, and the user had to wear both hearing aids and glasses at once or wear neither. Today, people who use both glasses and hearing aids can use in-the-ear types, or rest a BTE neatly alongside the arm of the glasses. There are still some specialized situations where hearing aids built into the frame of eyeglasses can be useful, such as when a person has hearing loss mainly in one ear: sound from a microphone on the "bad" side can be sent through the frame to the side with better hearing.


This can also be achieved by using CROS hearing aid or bi-CROS style hearing aids, which are now wireless in sending sound to the better side.


;Spectacle hearing aids
These are generally worn by people with a hearing loss who either prefer a more cosmetic appeal of their hearing aids by being attached to their glasses or where sound cannot be passed in the normal way, via a hearing aids, perhaps due to a blockage in the ear canal. pathway or if the client suffers from continual infections in the ear.
Spectacle aids come in two forms, ''bone conduction spectacles'' and ''air conduction spectacles''.


;Bone conduction spectacles
Sounds are transmitted via a receiver attached from the arm of the spectacles which are fitted firmly behind the boney portion of the skull at the back of the ear, (mastoid process) by means of pressure, applied on the arm of the spectacles. The sound is passed from the receiver on the arm of the spectacles to the inner ear (cochlea), via the bony portion. The process of transmitting the sound through the bone requires a great amount of power. Bone conduction aids generally have a poorer high pitch response and are therefore best used for ''conductive hearing losses'' or where it is impractical to fit standard hearing aids.


;Air conduction spectacles
Unlike the bone conduction spectacles the sound is transmitted via hearing aids which are attached to the arm or arms of the spectacles. When removing your glasses for cleaning, the hearing aids are detached at the same time. Whilst there are genuine instances where spectacle aids are a preferred choice, they may not always be the most practical option.


;Directional spectacles
These 'hearing glasses' incorporate a directional microphone capability: four microphones on each side of the frame effectively work as two directional microphones, which are able to discern between sound coming from the front and sound coming from the sides or back of the user.[http://www.aarpinternational.org/agingadvances_sub/agingadvances_sub_show.htm?doc_id=553940 Netherlands: Dutch Unveil 'Varibel' – The Eyeglasses That Hear]
The first electrical hearing aid used the carbon microphone of the telephone and was introduced in 1896. The vacuum tube made electronic amplification possible, but early versions of amplified hearing aids were too heavy to carry around. Miniaturization of vacuum tubes lead to portable models, and after World War II, wearable models using miniature tubes. The transistor invented in 1948 was well suited to the hearing aid application due to low power and small size; hearing aids were an early adopter of transistors. The development of integrated circuits allowed further improvement of the capabilities of wearable aids, including implementation of digital signal processing techniques and programmability for the individual user's needs.


Compatibility with telephones

A hearing aid and a telephone are "compatible" when they can connect to each other in a way that produces clear, easily understood sound. The term "compatibility" is applied to all three types of telephones (wired, cordless, and mobile). There are two ways telephones and hearing aids can connect with each other:



  • Acoustically: the ''sound'' from the phone's speaker is picked up by the hearing aid's microphone.

  • Electromagnetically: the ''signal'' inside the phone's speaker is picked up by the hearing aid's "telecoil" or "T-coil", a special loop of wire inside the hearing aid.


Note that telecoil coupling has nothing to do with the radio signal in a cellular or cordless phone: the audio signal picked up by the telecoil is the weak electromagnetic field that is generated by the voice coil in the phone's speaker 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 automatically switched off when the hearing aid is operating in telecoil mode, so background noise is not amplified. Since there is an electronic connection to the phone, the sound is clearer and distortion is less likely. But in order for this to work, the phone has to be hearing-aid compatible. More technically, the phone's speaker has to have a voice coil that generates a relatively strong electromagnetic field. Speakers with strong voice coils are more expensive and require more energy than the tiny ones used in many modern telephones; phones with the small low-power speakers cannot couple electromagnetically with the telecoil in the hearing aid, so the hearing aid must then switch to acoustic mode. Also, many mobile phones emit high levels of electromagnetic noise that creates audible static in the hearing aid when the telecoil is used. A workaround that resolves this issue on many mobile phones is to plug a wired (not Bluetooth) headset into the mobile phone; with the headset placed near the hearing aid the phone can be held far enough away to attenuate the static. Another method is to use a "neckloop" (which is like a portable, around-the-neck induction loop), and plug the neckloop directly into the standard audio jack (headphones jack) of a smartphone (or laptop, or stereo, etc.). Then, with the hearing aids' telecoil turned on (usually a button to press), the sound will travel directly from the phone, through the neckloop and into the hearing aids' telecoils.


The American National Standards Institute (ANSI) has a ratings scale for compatibility between hearing aids and phones:



  • When operating in acoustic (Microphone) mode, the ratings are from M1 (worst) to M4 (best).

  • When operating in electromagnetic (Telecoil) mode, the ratings are from T1 (worst) to T4 (best).


The best possible rating is M4/T4 meaning that the phone works well in both modes. Devices rated below M3 are unsatisfactory for people with hearing aids.


Computer programs that allow the creation of a hearing aid using a PC, tablet or smartphone are currently gaining in popularity. Modern mobile devices have all the necessary components to implement this: hardware (an ordinary microphone and headphones may be used) and a high-performance microprocessor that carries digital sound processing according to a given algorithm.
Application configuration is carried out by the user himself in accordance with the individual features of his hearing ability. The computational power of modern mobile devices is sufficient to produce the best sound quality. This, coupled with software application settings (for example, profile selection according to a sound environment) provides for high comfort and convenience of use.
In comparison with the digital hearing aid, mobile applications have the following advantages:



  • ease of use (no need to use additional devices, batteries and so on.);

  • high wearing comfort;

  • complete invisibility (smartphone is not associated with a hearing aid);

  • user-friendly interface of software settings;

  • high sampling frequency (44.1 kHz) providing for excellent sound quality;

  • Fast switching between the external headset and phone microphone;

  • acoustic gain is up to 30 dB (with a standard headset);

  • low delay in audio processing (from 6,3 to 15,7 ms – depending on the mobile device model);

  • No need to get used to it, when changing mobile devices;

  • No loss of settings when switching from one gadget to another and back again;

  • High duration of the battery;

  • free distribution of applications.
    It should be clearly understood that "hearing aid" application for smartphone / tablet cannot be considered a complete substitution of a digital hearing aid, since the latter:

  • is a medical device (exposed to the relevant procedures of testing and certification);

  • is designed for use by doctor's prescription;

  • is adjusted using audiometry procedures.
    Functionality of hearing aid applications may involve a hearing test (Audiometry#Types of audiometry) too. However, the results of the test are used only to adjust the device for comfortable working with the application. The procedure of hearing testing in any way cannot claim to replace an audiometry test carried out by a medical specialist, so cannot be a basis for diagnosis.

  • Apps such as Oticon ON for certain iOS (Apple) and Android devices can assist in locating a lost/misplaced hearing aid.http://www.oticon.global/solutions/accessories/connectivity, Retrieved 2016-09-25.


Wireless

Recent hearing aids include wireless hearing aids. One hearing aid can transmit to the other side so that pressing one aid's program button simultaneously changes the other aid, so that both aids change background settings simultaneously. FM listening systems are now emerging with wireless receivers integrated with the use of hearing aids. A separate wireless microphone can be given to a partner to wear in a restaurant, in the car, during leisure time, in the shopping mall, at lectures, or during religious services. The voice is transmitted wirelessly to the hearing aids eliminating the effects of distance and background noise. FM systems have shown to give the best speech understanding in noise of all available technologies.
FM systems can also be hooked up to a TV or a stereo.


2.4 gigahertz Bluetooth connectivity is the most recent innovation in wireless interfacing for hearing instruments to audio sources such as TV streamers or Bluetooth enabled mobile phones. Current hearing aids generally do not stream directly via Bluetooth but rather do so through a secondary streaming device (usually worn around the neck or in a pocket), this bluetooth enabled secondary device then streams wirelessly to the hearing aid but can only do so over a short distance. This technology can be applied to ready-to-wear devices (BTE, Mini BTE, RIE, etc.) or to custom made devices that fit directly into the ear.


Many theatres and lecture halls are now equipped with Assistive Listening Devices that transmit the sound directly from the stage; audience members can borrow suitable receivers and hear the program without background noise. In some theatres and churches FM transmitters are available that work with the personal FM receivers of hearing instruments.


Directional microphones

Most older hearing aids have only an omnidirectional microphone. An omnidirectional microphone amplifies sounds equally from all directions. In contrast, a directional microphone amplifies sounds from one direction more than sounds from other directions. This means that sounds originating from the direction the system is steered toward are amplified more than sounds coming from other directions. If the desired speech arrives from the direction of steering and the noise is from a different direction, then compared to an omnidirectional microphone, a directional microphone provides a better signal to noise ratio. Improving the signal-to-noise ratio improves speech understanding in noise. Directional microphones have been found to be the second best method to improve the signal-to-noise ratio (the best method was an FM system, which locates the microphone near the mouth of the desired talker).


Many hearing aids now have both an omnidirectional and a directional microphone mode. This is because the wearer may not need or desire the noise-reducing properties of the directional microphone in a given situation. Typically, the omnidirectional microphone mode is used in quiet listening situations (e.g. living room) whereas the directional microphone is used in noisy listening situations (e.g. restaurant). The microphone mode is typically selected manually by the wearer. Some hearing aids automatically switch the microphone mode.


Adaptive directional microphones automatically vary the direction of maximum amplification or rejection (to reduce an interfering directional sound source). The direction of amplification or rejection is varied by the hearing aid processor. The processor attempts to provide maximum amplification in the direction of the desired speech signal source or rejection in the direction of the interfering signal source. Unless the user manually temporarily switches to a "restaurant program, forward only mode" adaptive directional microphones frequently amplify the speech of other talkers in a cocktail party type environments, such as restaurants or coffee shops. The presence of multiple speech signals makes it difficult for the processor to correctly select the desired speech signal. Another disadvantage is that some noises often contain characteristics similar to speech, making it difficult for the hearing aid processor to distinguish the speech from the noise. Despite the disadvantages, adaptive directional microphones can provide improved speech recognition in noise


FM systems have been found to provide a better signal to noise ratio even at larger speaker-to-talker distances in 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 generates an electromagnetic field that can be detected by T-coils, allowing audio sources to be directly connected to a hearing aid. The T-coil is intended to help the wearer filter out background noise. They can be used with telephones, FM systems (with neck loops), and induction loop systems (also called "hearing loops") that transmit sound to hearing aids from public address systems and TVs. In the UK and the Nordic countries, hearing loops are widely used in churches, shops, railway stations, and other public places. In the U.S.A., telecoils and hearing loops are gradually becoming more common. Audio induction loops, telecoils and hearing loops are gradually becoming more common also in Slovenia.


A T-coil consists of a metal core (or rod) around which ultra-fine wire is coiled. T-coils are also called induction coils because when the coil is placed in a magnetic field, an alternating electric current is induced in the wire (Ross, 2002b; Ross, 2004). The T-coil detects magnetic energy and transduces (converts) it to electrical energy. In the United States, the Telecommunications Industry Association's TIA-1083 standard, specifies how analog handsets can interact with telecoil devices, to ensure the optimal performance.[http://ftp.tiaonline.org/UPED/20070717/UPED-20070717-010_TIA-1083_Flyer.pdf TIA-1083: A NEW STANDARD TO IMPROVE CORDLESS PHONE USE FOR HEARING AID WEARERS] . U.S. Telecommunications Industry Association


Although T-coils are effectively a wide-band receiver, interference is unusual in most hearing loop situations. Interference can manifest as a buzzing sound, which varies in volume depending on the distance the wearer is from the source. Sources are electromagnetic fields, such as CRT computer monitors, older fluorescent lighting, some dimmer switches, many household electrical appliances and airplanes.


The states of Florida and Arizona have passed legislation that requires hearing professionals to inform patients about the usefulness of telecoils.


=Legislation affecting use
=
In the United States, the Hearing Aid Compatibility Act of 1988 requires that the Federal Communications Commission (FCC) ensure that all telephones manufactured or imported for use in the United States after August 1989, and all "essential" telephones, be hearing aid-compatible (through the use of a telecoil).


"Essential" phones are defined as "coin-operated telephones, telephones provided for emergency use, and other telephones frequently needed for use by persons using such hearing aids." These might include workplace telephones, telephones in confined settings (like hospitals and nursing homes), and telephones in hotel and motel rooms. Secure telephones, as well as telephones used with public mobile and private radio services, are exempt from the HAC Act. "Secure" phones are defined as "telephones that are approved by the U.S. Government for the transmission of classified or sensitive voice communications."


In 2003, the FCC adopted rules to make digital telecommunications wireless telephones compatible with hearing aids and cochlear implants. Although analog wireless phones do not usually cause interference with hearing aids or cochlear implants, digital wireless phones often do because of electromagnetic energy emitted by the phone's Antenna (radio), backlight, or other components. The FCC has set a timetable for the development and sale of digital wireless telephones that are compatible with hearing aids. This effort promises to increase the number of digital wireless telephones that are hearing aid-compatible. Older generations of both cordless telephone and mobile phone phones used analog technology.


Direct audio input

Direct audio input (DAI) allows the hearing aid to be directly connected to an external audio source like a CD player or an assistive listening device (ALD). By its very nature, DAI is susceptible to far less electromagnetic interference, and yields a better quality audio signal as opposed to using a T-coil with standard headphones. An audio boot is a type of device that may be used to facilitate DAI.


Processing

Every electronic hearing aid has at minimum a microphone, a loudspeaker (commonly called a receiver), a battery, and electronic circuitry. The electronic circuitry varies among devices, even if they are the same style. The circuitry falls into three categories based on the type of audio processing (analog or digital) and the type of control circuitry (adjustable or programmable). Hearing aid devices generally do not contain processors strong enough to process complex Algorithm for sound source localization.


=Analog
=
Analogue electronics audio may have:
Adjustable control: The audio circuit is analog with electronic components that can be adjusted. The hearing professional determines the gain and other specifications required for the wearer, and then adjusts the analog components either with small controls on the hearing aid itself or by having a laboratory build the hearing aid to meet those specifications. After the adjustment the resulting audio does not change any further, other than overall loudness that the wearer adjusts with a volume control. This type of circuitry is generally the least flexible. The first practical electronic hearing aid with adjustable analog audio circuitry was based on US Patent 2,017,358, "Hearing Aid Apparatus and Amplifier" by Samual Gordon Taylor, filed in 1932.
Programmable control: The audio circuit is analog but with additional electronic control circuitry that can be programmed by an audiologist, often with more than one program. The electronic control circuitry can be fixed during manufacturing or in some cases, the hearing professional can use an external computer temporarily connected to the hearing aid to program the additional control circuitry. The wearer can change the program for different listening environments by pressing buttons either on the device itself or on a remote control or in some cases the additional control circuitry operates automatically. This type of circuitry is generally more flexible than simple adjustable controls. The first hearing aid with analog audio circuitry and automatic digital electronic control circuitry was based on US Patent 4,025,721, "Method of and means for adaptively filtering near-stationary noise from speech" by D Graupe, GD Causey, filed in 1975. This digital electronic control circuitry was used to identify and automatically reduce noise in individual frequency channels of the analog audio circuits and was known as the Zeta Noise Blocker.


=Digital
=
Digital data audio, programmable control: Both the audio circuit and the additional control circuits are fully digital. The hearing professional programs the hearing aid with an external computer temporarily connected to the device and can adjust all processing characteristics on an individual basis. Fully digital circuitry allows implementation of many additional features not possible with analog circuitry, can be used in all styles of hearing aids and is 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 analog hearing aids. Fully digital hearing aids can be programmed with multiple programs that can be invoked by the wearer, or that operate automatically and adaptively. These programs reduce acoustic feedback (whistling), reduce background noise, detect and automatically accommodate different listening environments (loud vs soft, speech vs music, quiet vs noisy, etc.), control additional components such as multiple microphones to improve spatial hearing, transpose frequencies (shift high frequencies that a wearer may not hear to lower frequency regions where hearing may be better), and implement many other features. Fully digital circuitry also allows control over wireless transmission capability for both the audio and the control circuitry. Control signals in a hearing aid on one ear can be sent wirelessly to the control circuitry in the hearing aid on the opposite ear to ensure that the audio in both ears is either matched directly or that the audio contains intentional differences that mimic the differences in normal 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 a “streamer”, that allows wireless connection to yet other external devices. This capability allows optimal use of mobile telephones, personal music players, remote microphones and other devices. With the addition of speech recognition and internet capability in the mobile phone, the wearer has optimal communication ability in many more situations than with hearing aids alone. This growing list includes voice activated dialing, voice activated software applications either on the phone or on the internet, receipt of audio signals from databases on the phone or on internet, or audio signals from television sets or from global positioning systems. The first practical, wearable, fully digital hearing aid was invented by Maynard Engebretson, Robert E Morley, Jr. and Gerald R Popelka. Their work resulted in United States patent law 4,548,082, "Hearing aids, signal supplying apparatus, systems for compensating hearing deficiencies, and methods" by A Maynard Engebretson, Robert E Morley, Jr. and Gerald R Popelka, filed in 1984. This patent formed the basis of all subsequent fully digital hearing aids from all manufacturers, including those produced currently.


The signal processing is performed by the microprocessor in real time and taking into account the individual preferences of the user (for example, increasing bass for better speech perception in noisy environments, or selective amplification of high frequencies for people with reduced sensibility to this range). The microprocessor automatically analyzes the nature of the external background noise and adapts the signal processing to the specific conditions (as well as to its change, for example, when the user goes outside from the building).


= Difference between digital and analog hearing aids
=
Analogue hearing aids make louder all the sounds picked up by the microphone. For example, speech and ambient noise will be made louder together. On the other hand, digital hearing aid (DHA) technology processes the sound using digital technology. Before transmitting the sound to the speaker, the DHA microprocessor processes the digital signal received by the microphone according to a mathematical algorithm. This allows just making louder the sounds of certain frequency according to the individual user settings (personal audiogram), and automatically adjusting the work of DHA to various environments (noisy streets, quiet room, concert hall, etc.).


For users with varying degrees of hearing loss it is difficult to perceive the entire frequency range of external sounds. DHA with multi-channel digital processing allows a user to "compose" the output sound by fitting a whole spectrum of the input signal into it. This gives users with limited hearing abilities the opportunity to perceive the whole range of ambient sounds, despite the personal difficulties of perception of certain frequencies. Moreover, even in this "narrow" range the DHA microprocessor is able to emphasize the desired sounds (e.g. speech), weakening the unwanted loud, high etc. sounds at the same time.


Advantages of digital aids include:
According to researches DHA have a number of significant advantages (compared to analog device hearing aids):



  • Digital signal processing helps to reduce noise and distinguish the speech signal from the overall spectrum of sounds which facilitates speech perception.

  • Reducing of background noise level increases the user’s comfort (especially in noisy environments, e.g. on the street).

  • Setting flexibility provides selective amplification of certain frequencies (in accordance with the personal characteristics of the hearing impaired).

  • Effective acoustic feedback reduction.

  • Possibility to use directional microphones, which greatly facilitates the perception of sound in certain environments, e.g., when talking face to face, or listening to the remote lecturer.

  • Extended frequency range (the ability to hear a large range of sounds).

  • “Self-learning" adaptive adjustment which facilitates usage of the device for a number of users.

  • Possibility of connecting devices (phones, smartphones, etc..).

  • In general, the maximum purification of the sound transmitted to user.
    These advantages of DHA were confirmed by a number of studies, relating to the comparative analysis of digital hearing aids of second and first generations and analog hearing aids.


Difference between PSAP and digital hearing aids


Personal Sound Amplification Products (abbreviated PSAP) are classified by the FDA as "personal sound amplification devices." These compact electronic devices are designed for people without hearing loss. Unlike hearing aids (which FDA classifies as devices to compensate for hearing impairment) use of PSAP does not require medical prescription. Such devices are used by hunters, naturalists (for audio observation of animals or birds), ordinary people (for example, to increase the volume of the TV in a quiet room), etc.
PSAP models differ significantly in price and functionality. Some devices simply amplify sound. Others contain directional microphones, equalizers to adjust the audio signal gain and filter noise.Beck, Melinda, [https://www.wsj.com/articles/SB120156046709123567 “Getting an Earful: Testing A Tiny, Pricey Hearing Aid”], ''The Wall Street Journal,'' Jan. 29, 2008. Retrieved 2013-05-23.


History



The invention of the carbon microphone, transmitters, digital signal processing chip or Digital signal processor, and the development of computer technology helped transform the hearing aid to its present form.Howard, Alexander (26 November 1998). [https://www.nytimes.com/1998/11/26/technology/hearing-aids-smaller-and-smarter.html "Hearing Aids: Smaller and Smarter."] The work was conducted with the help of the "big" computer of that time. Although they could not claim to be a real hearing aids (their performance was not enough for audio processing in real time – not to mention the size), they carried out successful studies of the various hardware circuits and algorithms for processing audio signals. The software package BLODI (stands for Block of Compiled Diagrams) developed by Kelly, Lockbaum and Vysotskiy in 1961 allowed to simulate any sound system provided in the form of a block diagram. With its help a special phone for users with hearing impairments was created. In 1967, Harry Levitt used BLODI to simulate a hearing aid on a digital computer.


Almost ten years later the second step was taken – the creation of "quasi-digital" hearing aid, in which the analog components and digital programmable module was combined into a single compact case. In this device the digital controller not only controlled the analog components (amplifiers, filters and signal limiter), but it could be programmed by connecting an external computer (in the laboratory – with medical supplies of hearing aids).


The concept of quasi-digital device was very successful from a practical point of view because of the low power consumption and compact size. At that time, low-power analog amplifier technology was developed very well – in contrast to the semiconductor chips necessary for a "real" digital camera. The combination of high performance analog components and digital signal processing capability has led to the creation module successful production parts.


The hearing aid of this type was developed by Etymonic Design. A little later, Mangold and Lane created a programmable multi-channel hearing aid. A similar approach was applied by Similarly, Graupe with co-authors for developing of an adaptive noise filter on a single crystal. This relatively small chip had low power consumption and fit in the case of ordinary BTE or ITC hearing aid.


The third stage of development was the appearance of "real" digital hearing aids. In DHA all stages of sound processing are carried out in binary form. To do this, an external sound from a microphone first converted into a binary code, and after the conversion the reverse transformation is carried out (to analog signal transmitted by the ear speaker in the form of sound). The first "real" DHA were models developed by Graup in 1970 on the basis of the 8080 microprocessor, which replaced the analog components (amplifier, limiter and filters). The possibilities of a programmable processor made the device self-adjusting, which opened the prospects for the use of advanced signal processing techniques, noise reduction, etc. Although the 8080th processor was relatively slow and big in size.


Further development of the DHA is associated with the creation of microprocessors with parallel processing of data arrays. As a result, a significant decrease of calculations time gave the opportunity to conduct processing of audio signal in real time. The small size of microchips (as of 1987) allowed creating compact hearing aids not exceeding the dimensions of their analog "predecessors" on their basis. However, for ITC aids these processors were not yet sufficiently compact. In all other respects, "full" DHA of that period was very similar to modern models.


Regulation


Ireland

Like much of the Irish health care system, hearing aid provision is a mixture of public and private.


Hearing aids are provided by the State to children, OAPs and to people whose income is at or below that of the State Pension. The Irish State hearing aid provision is extremely poor; people often have to wait for two years for an appointment.


It is estimated that the total cost to the State, of supplying one hearing aid, exceeds €2,000.


Irish taxpayers can also claim tax relief, at the standard rate, as hearing aids are recognised as a medical device.


Hearing aids in the Republic of Ireland are exempt from VAT.


Hearing aid providers in Ireland mostly belong to the Irish Society of Hearing Aid Audiologists.


United States

Ordinary hearing aids are Medical device#Class I: General controls regulated medical devices under Federal Food and Drug Administration (FDA) rules. (a) (2005). A 1976 statute explicitly prohibits any state requirement that is "different from, or in addition to, any requirement applicable" to regulated medical devices (which includes hearing aids) which relates "to the safety and effectiveness of the device." Inconsistent state regulation is preempted under the federal law.Missouri Board of Examiners for Hearing Instrument Specialists v. Hearing Help Express, Inc., 447 3d 1033 (8th Cir. 2006) In the late 1970s, the FDA established federal rules governing hearing aid sales,Final Rule issued in Docket 76N-0019, (15 February 1977). and addressed various requests by state authorities for exemptions from federal preemption, granting some and denying others.
Exemption from Preemption of State and Local Hearing Aid Requirements; Applications for Exemption, Docket No. 77N-0333, (10 October 1980).


Cost



Several industrialized countries supply free or heavily discounted hearing aids through their Publicly funded health care.


Australia

The Australian Department of Health and Ageing provides eligible Australian citizens and residents with a basic hearing aid free-of-charge, though recipients can pay a "top up" charge if they wish to upgrade to a hearing aid with more or better features. Maintenance of these hearing aids and a regular supply of batteries is also provided, on payment of a small annual maintenance fee.


Canada

In Canada, health care is a responsibility of the Provinces and territories of Canada. In the province of Ontario, the price of hearing aids is partially reimbursed through the Assistive Devices Program of the Ministry of Health and Long-Term Care (Ontario), up to $500 for each hearing aid. Like eye appointments, audiological appointments are no longer covered through the provincial public health plan. Audiometric testing can still easily be obtained, often free of charge, in private sector hearing aid clinics and some ear, nose and throat doctors offices. Hearing aids may be covered to some extent by private insurance or in some cases through government programs such as Veterans Affairs Canada or Workplace Safety & Insurance Board.


Iceland

Social Insurance pays a one time fee of ISK 30,000 for any kind of hearing aid. However, the rules are complicated and require that both ears have a significant hearing loss in order to qualify for reimbursement. BTE hearing aids range from ISK 60,000 to ISK 300,000.[http://www.tr.is/english Social Insurance Administration – Iceland] Accessed 30 November 2007


India

In India hearing aids of all kinds are easily available. Under Central and state government health services, the poor can often avail themselves of free hearing devices. 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 Department of Health worked with Action on Hearing Loss (then called RNID) to improve the quality of NHS hearing aids so every NHS audiology department in England was fitting digital hearing aids by March 2005. By 2003 Over 175,000 NHS digital hearing aids had been fitted to 125,000 people. Private companies were recruited to enhance the capacity, and two were appointed – David Ormerod Hearing Centres, partly owned by Alliance Boots and Ultravox Group, a subsidiary of Amplifon.


Within the UK, the National Health Service provides digital BTE hearing aids to NHS patients, on long-term loan, free of charge. Other than BAHAs (Bone anchored hearing aid), where specifically required, BTEs are usually the only style available. Private purchases may be necessary if a user desires a different style. Batteries are free.[http://www.rnid.org.uk/VirtualContent/101701/NHS_hearing_aid_service_September_2009.pdf NHS hearing aid service fact sheet] Accessed 26 November 2007


Batteries


While there are some instances that a hearing aid uses a rechargeable battery or a long-life disposable battery, the majority of modern hearing aids use one of five standard Watch battery Zinc–air battery. (Older hearing aids often used mercury battery cells, but these cells have become banned in most countries today.) Modern hearing aid button cell types are typically referred to by their common number name or the color of their packaging.


They are typically loaded into the hearing aid via a rotating battery door, with the flat side (case) as the positive terminal (cathode) and the rounded side as the negative terminal (anode).


These batteries all operate from 1.35 to 1.45 volts.


The type of battery a specific hearing aid utilizes depends on the physical size allowable and the desired lifetime of the battery, which is in turn determined by the Electric power draw of the hearing aid device. Typical battery lifetimes run between 1 and 14 days (assuming 16-hour days).








































































































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! style="width:10%;"Standard Names
! style="width:50%;"Misc Names
-
style="background:blue; color:white;"67511.6 mm × 5.4 mmHigh-Power Hearing aid#Behind the ear aids (BTE)BTEs, Cochlear implantsCochlear ImplantsInternational Electrotechnical CommissionIEC: PR44, ANSI: 7003ZD675, 675A, 675AE, 675AP, 675CA, 675CP, 675HP, 675HPX, 675 Implant Plus, 675P (HP), 675PA, 675SA, 675SP, A675, A675P, AC675, AC675E, AC675E/EZ, AC675EZ, AC-675E, AP675, B675PA, B6754, B900PA, C675, DA675, DA675H, DA675H/N, DA675N, DA675X, H675AE, L675ZA, ME9Z, P675, P675i+, PR44, PR44P, PR675, PR675H, PR675P, PR-675PA, PZ675, PZA675, R675ZA, S675A, V675, V675A, V675AT, VT675, XL675, Z675PX, ZA675, ZA675HP
-
style="background:orange; color:black;"137.9 mm × 5.4 mmHearing aid#Behind the ear aids (BTE)BTEs, In-the-earITEsInternational Electrotechnical CommissionIEC: PR48, ANSI: 7000ZD13, 13A, 13AE, 13AP, 13HP, 13HPX, 13P, 13PA, 13SA, 13ZA, A13, AC13, AC13E, AC13E/EZ, AC13EZ, AC-13E, AP13, B13BA, B0134, B26PA, CP48, DA13, DA13H, DA13H/N, DA13N, DA13X, E13E, L13ZA, ME8Z, P13, PR13, PR13H, PR-13PA, PZ13, PZA13, R13ZA, S13A, V13A, VT13, V13AT, W13ZA, XL13, ZA13
-
style="background:brown; color:white;"3127.9 mm × 3.6 mmminiHearing aid#Behind the ear aids (BTE)BTEs, Hearing aid#Receiver In the Canal/Ear (RIC/RITE)RICs, Hearing aid#In the canal (ITC), mini canal (MIC) and completely in the canal aids (CIC)ITCsInternational Electrotechnical CommissionIEC: PR41, ANSI: 7002ZD312, 312A, 312AE, 312AP, 312HP, 312HPX, 312P, 312PA, 312SA, 312ZA, AC312, AC312E, AC312E/EZ, AC312EZ, AC-312E, AP312, B312BA, B3124, B347PA, CP41, DA312, DA312H, DA312H/N, DA312N, DA312X, E312E, H312AE, L312ZA, ME7Z, P312, PR312, PR312H, PR-312PA, PZ312, PZA312, R312ZA, S312A, V312A, V312AT, VT312, W312ZA, XL312, ZA312
-
style="background:yellow; color:black;"105.8 mm × 3.6 mmHearing aid#In the canal (ITC), mini canal (MIC) and completely in the canal aids (CIC)CICs, Hearing aid#Receiver In the Canal/Ear (RIC/RITE)RICsInternational Electrotechnical CommissionIEC: PR70, ANSI: 7005ZD10, 10A, 10AE, 10AP, 10DS, 10HP, 10HPX, 10SA, 10UP, 20PA, 230, 230E, 230EZ, 230HPX, AC10, AC10EZ, AC10/230, AC10/230E, AC10/230EZ, AC230, AC230E, AC230E/EZ, AC230EZ, AC-230E, AP10, B0104, B20BA, B20PA, CP35, DA10, DA10H, DA10H/N, DA10N, DA230, DA230/10, L10ZA, ME10Z, P10, PR10, PR10H, PR230H, PR536, PR-10PA, PR-230PA, PZA230, R10ZA, S10A, V10, VT10, V10AT, V10HP, V230AT, W10ZA, XL10, ZA10
-
style="background:red; color:white;"55.8 mm × 2.1 mmCICsInternational Electrotechnical CommissionIEC: PR63, ANSI: 7012ZD5A, 5AE, 5HPX, 5SA, AC5, AC5E, AP5, B7PA, CP63, CP521, L5ZA, ME5Z, P5, PR5H, PR-5PA, PR521, R5ZA, S5A, V5AT, VT5, XL5, ZA5
}

See also



  • Cochlear implant

  • Ear trumpet

  • Electronic nose

  • El Deafo (Cece Bell novel)

  • Orkney Wireless Museum – has a 1930s Ardent hearing aid in its collection

  • Sonotone 1010 – first electronic hearing aid to use a transistor

  • Spatial hearing loss


References





Learn more about Hearing Aid Services:

https://en.wikipedia.org/wiki/Hearing Aid