Programmable hearing aids can be either analogue or digital and are distinguished by their technology or circuitry which allows various environmental settings to be custom programmed into the aid.
Analogue Programmable Hearing Aids
Conventional analogue hearing aids are designed with a particular frequency response based on your audiogram. The registered hearing aid dispenser t tells the manufacturer what settings to install. Although there are some adjustments, the aid essentially amplifies all sounds (speech and noise) in the same way. This technology is the least expensive and it can be appropriate for many different types of hearing loss.
Newer model analogue programmable hearing aids have a microchip which allows the aid to have settings programmed for different listening environments such as quiet conversation in your home, noisy situations like a restaurant, or large areas like a theater. The registered hearing aid dispenser uses a computer to program the hearing aid for different listening situations depending on your individual hearing loss profile, speech understanding, and range of tolerance for louder sounds.
Some aids can store several programs. As your listening environment changes, you can change the hearing aid settings by pushing a button on the hearing aid or by using a remote control to switch channels. The aid can be reprogrammed by the audiologist if your hearing or hearing needs change. These aids are more expensive than conventional analogue hearing aids, but generally have a longer life span and may provide better hearing for you in different listening situations.
Digital programmable hearing aids
Digital programmable hearing aids have all the features of analogue programmable aids but use "digitised sound processing" to convert sound waves into digital signals. A computer chip in the aid analyses the signals of your environment to determine if the sound is noise or speech and then makes modifications to provide a clear, amplified distortion-free signal. Digital hearing aids are usually self-adjusting. The digital processing allows for more flexibility in programming the aid so that the sound it transmits matches your specific pattern of hearing loss. This digital technology is the most expensive, but it allows for improvement in programmability, greater precision in fitting, management of loudness discomfort, control of acoustic feedback (whistling sounds), and nose reduction.
Programmable hearing aids have a programming port for connecting to the audiologists computer. Your hearing specialist can adjust the intensity (gain) for soft and moderate sounds in a few minutes. Programmable aids may have linear or digital amplification.
- Advanced Signal processing -
Advanced signal processing adjusts the amount of amplification (gain) the hearing aid provides according to the loudness of the sound reaching its microphone. For example, louder sounds are amplified less than softer sounds. Traditional hearing aid circuits provide a set amount of gain regardless of the loudness of the sound reaching the microphone. This can result in softer sounds remaining too soft and louder sounds being uncomfortably loud. - Multi-channel Capability -
The amount of gain a hearing aid provides at each pitch of frequency is called its frequency response. Some programmable hearing aids can divide the frequency response into two or more channels of control. Each channel can be adjusted independently so that different advanced signal processing schemes can be applied to each frequency region. This allow the hearing aid to respond differently for low pitched sounds than for high-pitched sounds, better accommodating a hearing-aid user with recruitment. Because recruitment may be present only at some pitches, multi-channel capability provides more flexibility to meet this need. - Multi-Memory Capability -
Some programmable hearing aids have memory, allowing them to store more than one frequency response or program. Multiple memories allow the user to choose from different frequency responses or signal processing schemes with a remote control or by pressing a button on the hearing aid. This is useful for those who communicate in many different listening situations or have fluctuating hearing loss. The audiologist and the hearing aid wearer together decide which hearing aid response to store in memory based on the wearer's most frequent and demanding listening situations (for example, listening to music or going to a restaurant). - Multi-Microphone Capability -
One programmable hearing aid has two separate microphones, one that picks up sound from a broad area and one that picks up from a narrower range. This is similar to a camera having a wide angle and zoom lens. In noisy listening situations the zoom microphone can suppress sounds that come from behind (usually competing noise), improving the hearing-aid user's ability to hear speech that comes from in front. The hearing-aid user can choose between microphones as listening situations vary.
