UT Health Physicians

Information on Hearing Aids

What are hearing aids?

Approximately, 80 percent of hearing impairments are permanent in nature. The typical treatment of permanent hearing loss is the recommendation of hearing aids. A hearing aid is a small electroacoustic device which typically fits in or behind the ear, and is designed to amplify and modulate sound for the wearer.  A hearing aid has three basic parts. The parts are a microphone, amplifier and speaker. The hearing aid receives sound through a microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them to the ear through a speaker.

Digital technology

The digital revolution has made a huge impact on the way hearing aids look, feel and function. They can be so small that they are virtually invisible, so "cool" looking that you will want everyone to see them and so natural sounding, they mimic the way you used to hear before you experienced hearing loss.

Until recently, the majority of hearing aids utilized analog signal processing. Ttoday, nearly all hearing aids sold in the U.S. utilize digital signal processing. Because of the way digital technology converts sound waves, digital hearing aids can be specially programmed to amplify some frequencies more than others. Digital circuitry gives your audiologist more flexibility in adjusting the hearing aid to your specific needs.

Digital technology offers some exciting features. These may vary in the specific hearing aid selected for you.

Some of the features available include:

  • Multiple adaptive directional microphones will help you hear better in noisy situations.
  • Open-fit technology keeps the ear canal unobstructed and helps to eliminate the feeling of fullness or echo-quality in the hearing aid wearer’s voice.
  • Dynamic feedback cancellation eliminates annoying whistles from your hearing aid.
  • Automatic program adjustments allows the hearing aids to adjust to your listening environment, whether you are on the phone, in a crowd or in wind.
  • Wireless communication and binaural synchronization ensures the hearing aids are working together instead of as two separate devices.
  • Wireless and bluetooth accessories allow you to hear your cell phone, television and home phone directly through your hearing aids.


There are many types of hearing aids, also known as hearing instruments, which vary in size, power and circuitry. There are hearing aids to fit any lifestyle.

Among the different sizes and models are:

  • In the ear or full shell (ITE or FS)
  • Half shell (HS)
  • In the canal (ITC)
  • Completely in the canal (CIC)
  • Behind the ear (BTE)
  • Open ear mini behind the ear