What is a hearing aid?
A hearing aid or external hearing aid is a small electronic device that is placed in the ear, either inside or behind the ear. This device amplifies external sound, processes it and conducts it more clearly and efficiently to the inner ear.
Why is it used?
This device is intended to improve the hearing ability of a patient who has suffered moderate or severe hearing loss. It behaves like a small loudspeaker, perceived only by the hearing aid wearer, specific to the patient’s affected sound frequencies, allowing for improved communication and interaction with others.
What does it consist of?
The device receives the external sound from a small microphone which, subsequently, converts them into electrical signals. With the help of an amplifier, the hearing aid increases the volume of these signals and sends them back to the patient’s ear through a loudspeaker.
Digital hearing aids also have a microchip that processes the acoustic signal, adapting automatically to elaborate the best response according to the environment in which the user is.
Types of hearing aids
- In-the-ear hearing aid (ITE)
It is used in cases of mild to severe hearing loss. It is custom-made, since it must be adapted to the external part of the ear. It is not recommended for use in children because it must be adjusted according to the development of the ear. Its size may cause coupling problems. The amplifying power is somewhat more limited than BTEs.
- In-the-canal (ITC) hearing aid.
It is small in size, fits in the ear canal and only a small part of the hearing aid is shown. Care must be taken to ensure that it does not become damaged due to earwax accumulation. It is also custom-made and is suitable for mild to severe hearing loss.
- Intracanal Internal Canal Hearing Aid (CIC)
This type of hearing aid is like the ITC but, more discreet. It improves mild/moderate hearing loss; it is not recommended for severe hearing loss. Due to its size, it may be difficult to remove.
- Behind-the-ear hearing aid (BTE)
Placed in the back of the ear and connected to an earmold that goes inward. It is recommended for patients with severe deafness and for children. The volume can be controlled.
Alternatives to this treatment
Surgical treatment is recommended for severe deafness. This operation consists of incorporating a cochlear implant, a transducer. It consists of two parts, external and internal.
- External: An external microphone is installed to send the signals to a voice processor, which encodes the sounds to send them to a transmitter.
- Internal: The message is transmitted to an internal osseointegrated implant (high-tech electronic device), in the mastoid bone, behind the pinna. This message flows through an electrode that reaches the auditory nerve and the cochlea (inner ear).
This text has been reviewed by Dr. Franklin Mariño Sánchez, of the Rhinology and Skull Base Surgery Unit, Otorhinolaryngology Service, Hospital Universitario Ramón y Cajal.