The early hearing aid was a funnel and trumpet which focused the sound into the ear the first battery operated hearing aid was invented by Harvey Fletcher of the Bell Laboratories. A hearing aid is a small device which is battery powered and fits either in or behind the users ear it is an electro acoustic gadget which amplifies and regulates sound making the wearer able to have a better hearing experience depending on their level of deafness.
In the market of hearing instruments there are many types which vary in size power and electronics
Body worn aids
These where the very first hearing aids which was basically a boxed amplifier and battery which you carried in your pocket with a lead attached to a moulded ear piece with a tiny loudspeaker built in to it.
Behind the ear aids (BTE)
These devices consist of a case which sits behind the ear with a connection to an ear moulded or dome device which fits into the ear. All the electronics and battery are in the case and the loudspeaker in the moulded unit in the ear. The sound to the ear piece can also be acoustically or electrically routed.
Receiver in the Canal/Ear (CRT/RIC/RITE)
BTE hearing devices that place the ear piece loudspeaker directly in the ear without a fitted ear mold are often referred to as “Receiver in the Canal” devices. These devices use soft ear inserts made with materials such as silicone. The advantage of this type of device is better sound quality and lower case size with open fit scientific know-how with easy instant fitting.
Made from an impression taken from the user’s outer ear making this a cosier fit and lessens the chances of any feedback. They can be made from various materials and colours.
In the ear aids (ITE)
These types of hearing aids fit in the outer ear bowl (called the concha); they can be seen when meeting face to face with someone. These hearing aids are custom made to fit the user’s ear.
They can be used in mellow to some severe hearing losses. Feedback, a squealing/whistling caused by high frequency sound leaking and being amplified again, can be a problem for severe hearing losses. Some models have systems which are able to provide feedback to control this. Venting can also cause feedback. A vent is a tube mainly placed to offer pressure equalization.
Invisible in canal hearing aids (IIC)
These hearing aids are not visible when worn because it fits deeper into the ear canal than other types of hearing aids, so good that you cannot see even looking straight into the ear bowl this is because they are custom made to fit into the ear canal.
Extended wear hearing aids
Extended wear hearing aids are hearing aids which are non-surgically fitted in the ear canal by a hearing specialist.
The extended wear hearing aid represents the first “invisible” hearing aid. These aids are worn for about 1–3 months at a time without removal. Being made of soft material they are fitted close to the ear drum which can increase sound performance with less feedback with much improved high frequency gain. They are a great improvement on the more traditional BTC & ITC range of hearing devices where daily insertion and removal took place.
“Open-fit” or “Over-the-Ear” (OTE) hearing devices are tiny behind-the-ear type hearing aids. They minimise the amount of effect on the ear canal resonances, as it leaves the ear canal as open as possible. Having a small loudspeaker that sits in the canter of the ear canal these devices are fitted behind the ear with a tiny clear tube going into the ear canal with a tiny soft silicone moulded dome shaped tip holding the tube in place.
Personal, User, Self, or Consumer Programmable
The personal programmable, consumer programmable, consumer adjustable, or self programmable hearing device allows the user to alter their own hearing aid control settings using their own PC. Manufacturers and dealers can adjust these hearing aids for the customer. They are available in styles and colours and differ from other types of hearing aids as they are programmable cy the user.
Disposable hearing aids
These hearing aids are disposable once the battery life is gone they are thrown away these types of hearing aids are fitted by hearing aid specialists and removed by the same.
Bone Anchored Hearing Aids (BAHA)
The BAHA is an auditory prosthetic based on bone conduction that can be surgically inserted. It is an option for patients without external ear canals, when normal hearing aids with a mould in the ear cannot be used.
The BAHA uses the skull as a route for sound to travel to the inner ear. For patients with conductive hearing loss, the BAHA sidesteps the external auditory canal and the middle ear, activating the operating cochlea. For people with unilateral hearing loss, the BAHA uses the skull to channel the sound from the deaf side to the side with the working cochlea.
The procedure has a minimal discomfort and pain for the patient and is a simple procedure for an experienced ear surgeon. One of the good features is that if a patient does not get on with this type of hearing aid it is a very easy to undo and can take less than a minute.
The BAHA hearing aid can be connected to an FM system by linking a miniaturized FM receiver to it.
In the late 1950s and through to the 1970s, before in-the-ear aids became popular (and when thick-rimmed eyeglasses were fashionable), People combined the hearing aid which was built into the temple part of the glasses. But they had limited styles but nowadays using CROS or bi-CROS style hearing aids, which are now wireless in sending sound to the better side.