The term digital is used for most of today’s current technology, from televisions to cell phones. Hearing aids today are digital, which means incoming sound is converted into a series of numbers which are then processed using mathematical equations. Digital processing enables very complex manipulation of sound, for example, to separate speech from noise. A few digital instruments are capable of 1.8 million calculations per second.
The digital technology within hearing aids allows sounds to be separated into different frequency regions, or bands, and amplify each region selectively, depending on the hearing aid user’s hearing loss. In addition, the advanced digital processing within the hearing aid enables different amounts of amplification for soft, moderate, and loud sounds, so that soft sounds are audible, but loud sounds are not uncomfortable or over amplified. Digital signal processing allows amplification to occur with minimal distortion, resulting in a more natural sound quality.
Digital hearing aids are programmable, meaning the hearing aid settings can be precisely fine-tuned, and special features can be adjusted for each wearer by the Audiologist, using special hearing aid software on a computer. Hearing aids are programmed and customized for both the hearing loss, the preferences, and the lifestyles of the person who wears them.
In addition to basic the basic digital signal processing discussed above, many hearing aid manufacturers offer different hearing aid models, based upon the sophistication of audio processing technology. The more sophisicatied and advanced digital hearing aids tend to be more automatic in that they better adapt the audio processing profile to the specific environment encountered. The more sophisticated hearing aids are best suited for individuals who often find themselves trying to listen in challenging audio environments. Examples of some of these advanced features, what they do and how they benefit the hearing aid wearer are:
- Directional Microphones – Two microphones on the hearing aids work together to give preference to sounds in front of the wearer and reduces sound, especially noise, from behind the wearer. This technology has been proven in research to improve speech understanding in background noise. In some more sophisticated digital hearing aids, the focus point for speech can be configured to be to the right, left or behind the person. This enhances listening benefit in difficult situations, such as the car.
- Noise Reduction – Determines if signal contains unwanted background noise and reduces the level of background noise if present. This noise reduction circuitry is most effective in squelching a steady-state noise which has a diffrent acoustical envelope or “signature” than speech, such as road noise or a fan. The outcome of this specialized noise reduction circuitry is that the background noise is less annoying, and the user’s listening comfort is improved in noisy situations.
- Feedback Management – Reduces or eliminates whistling that can occur with hearing aid use. The advanced digital technology eliminates any whistling from the hearing aid without compromising volume or sound quality.
- Wind Noise Reduction – Reduces the noise created from wind blowing across the hearing aid’s microphone(s). This is designed to improve comfort for people who spend a lot of time outdoors.
- Data Logging/Learning – The ability of the hearing aid to track and learn the hearing aid user’s preferences in various listening environments. This information can assist the Audiologist in making future programming adjustments and allows the hearing aid to adapt to the user’s preferences.
- Bluetooth Interface – Establishes a wireless connection between hearing aids and Bluetooth compatible devices such as cell phones, computers, televisions, remote microphones, etc.