Frequently Asked Questions
What is the difference between digital hearing aids and other types?
Behind-the-ear (BTE) hearing aids
These usually have an earmold that sits inside your ear. The hearing aid rests behind your ear and a plastic tube connects it to the earmold. This is the most common type of hearing aid – most NHS digital hearing aids are BTE aids.
There is a new alternative way of fitting BTE aids that does not involve an earmold. This is called an ‘open ear fitting’ and uses a smaller, soft earpiece at the tip of the tubing instead of an earmold. These fittings are less visible than earmolds but are only suitable if your hearing loss is mild. They give you a very natural sound.
In-the-ear (ITE) and in-the-canal (ITC) hearing aids
These have their working parts in the earmold, so the whole aid fits into your ear. They tend to need repairing more often than behind-the-ear aids. Some in-the-ear aids can be seen from the side. The smallest ITC aids fit right inside your ear canal, where they can hardly be seen at all. If you have a severe hearing loss, or very narrow ear canals, these aids will probably not suit you.
Body-worn hearing aids
These have a small box that you clip to your clothes or put in your pocket. This box contains the microphone and working parts. It is connected by a lead to an earphone clipped into your earmold. Body-worn hearing aids may be suitable if you have sight problems, or problems using very small switches or buttons. Some models are very powerful.
How You Hear
The human ear is a very intricate structure, and the system by which your ear converts the energy in sound waves into electrical signals for your brain is enormously complex. Even today some of the mechanisms are not yet clearly understood. But, in general terms the system works like this:
Hearing starts at the outer ear. The auricle collects sound waves which are directed through the ear canal and move the eardrum. As the eardrum vibrates with sound, these vibrations pass across the middle ear chamber by way of the three small bones of the middle ear. The inner ear contains the mechanisms of hearing and balance. The vibrations of the ossicles set up waves of pressure in the fluid in the inner ear. These waves pass to tiny hair cells in the inner ear that convert this to electrical signals and pass these to the brain.
1.) The Outer Ear: The outer ear is comprised of the pinna, ear canal, and outer layer of the eardrum. Sound enters the ear canal. At the eardrum, sound energy (air pressure changes) are transformed into mechanical energy of eardrum movement.
2.) Pinna: The pinna is composed of cartilage and has a relatively poor blood supply. Its presence on both sides of the head allows us to localize the source of sound from the front vs. the back. Our ability to localize from side to side depends on the relative intensity and relative phase of sound reaching each ear and the analysis of the phase/intensity differences within the brainstem. And, of course, the lobe of the pinna is handy for single or multiple hoops, loops, diamonds, etc.
3.) Cartilaginous Portion of External Ear Canal: The ceruminous and sebaceous glands in the cartilaginous portion of the ear canal combine to produce cerumen. The total length of the ear canal in adults is approximately one inch, which gives it a resonance frequency of approximately 3400 Hz, an important frequency region for understanding speech.
4.) Bony Portion of External Ear Canal: The bony portion of the ear canal is surrounded by the mastoid bone and occupies the inner third, and is very tender. Occasionally, completely in the canal (CIC) hearing aids will reach as far as this portion of the canal. Outgrowths of bone, called exostoses occasionally will grow in the bony portion of the ear canal in response to cold-water exposure.
5.) Mastoid Air Cells: A portion of the temporal bone (surrounding the ear). Under normal circumstances these honeycombed area cells are filled with air. They can fill with fluid or pus when chronically infected.
6.) Tympanic Membrane: The tympanic membrane actually has three layers, with the outer layer continuous with the skin of the outer ear canal. The upper portion of the TM is called the pars flaccida, while the lower portion is called the pars tensa. The central portion of the pars tensa provides the active vibrating area in response to sound. The TM is a continually growing structure, which allows it to close if it has a hole in it and to extrude a ventilation tube.
7.) Middle Ear: The middle ear serves as an impedance-matching transformer, matching the impedance of air in the ear canal to the impedance of the perilymph of the inner ear.
8.) Malleus: The malleus is the most lateral (toward the side of the head) of the three ear bones (ossicles) in the middle ear. The long process of the malleus is attached to the inner layer of tympanic membrane. When the TM vibrates in response to sound, the malleus vibrates in concert.
9.) Incus: The incus is attached to the malleus, and so vibrates as the malleus vibrates. The long process of the incus is also attached to the head of the stapes. Because the long process of the incus is slightly shorter than the long process (manubrium) of the malleus, incoming sound is given a slight (2.5 dB) boost in energy. This is referred to as the lever advantage.
10.) Stapes: The stapes has a footplate and a superstructure. Its footplate is seated in the oval window, which separates the middle ear from perilymph of the inner ear. As the long process of the incus vibrates, so does the footplate of the stapes. Because the vibrating area of the tympanic membrane is larger than the area of the stapes, incoming sound is given a significant boost in energy of over 20 dB. This is referred to as the hydraulic advantage.
11.) Choclea: A snail shaped structure that is the sensory organ of hearing. The vibrational patterns that are initiated by vibration of the stapes footplate set up a traveling wave pattern within the cochlea. This wavelike pattern causes a shearing of the cilia of the outer and inner hair cells. The shearing causes hair cell depolarization, resulting in all or none neural impulses that the brain interprets as sound.
Contact Advanced Hearing Technologies, Inc. today at 1-888-333-5744 or by email to learn more about digital hearing aids and how to schedule a FREE hearing test and evaluation
Hearing Aids: Tips for Those With Tinnitus
by Lerner de Luca
If you suffer from Tinnitus, you are well aware that certain pitches may negatively affect you via the hearing aid you are wearing.
In this case, it is necessary to adjust the compression dial and setting of the hearing aid to prevent loud noises from entering within the canal of the ear.
In addition it is vital to utilize the real ear measurement method because everyone’s ear will be different in shape and dimensions- in this case we are addressing the ear canal as well as the shape of the ear drum, and other factors. In general, those who have smaller ear canals will be more sensitive to these “loud noises” as opposed to someone who has a larger ear canal.
The best way to go about this is to speak with your audiologist on how to adjust it properly so it doesn’t irritate your ear canal any more than it already has.
Normally it will take a bit of time before the new settings will “kick in” and when you will notice whether the calibration is on target or a bit off. Again, having some professional assistance is the way to go with this and other matters with regards to your hearing aid issues and concerns.