Hearing aid technology has improved a lot over the past few decades, but at their core, hearing aids have always been consist of four basic parts: a microphone, a processor, a receiver and a power source. The microphone picks up the sounds in your environment and passes it to the processor. The processor enhances the signal and delivers it to the receiver which delivers the amplified signal to the ear canal. The power source, or battery, drives the system.
Hearing aid technology can be considered either advanced or basic, based on the integrity of the processor. Even today’s basic digital hearing aids offer far more advantage than the best hearing aids of previous generations.
Although programmable by computer, basic hearing aids generally have limited adjustments available for fine-tuning to fit unusual patterns of hearing loss. They are also less customizable and automated than hearing aids with advanced technology.
Basic digital hearing aids generally require the wearer to make some manual adjustments in certain listening situations such as turning a volume control up or down, or pushing a button on the aids in order to reduce noise coming from behind.
The processor may separate incoming signals into two or more channels and process each channel separately. For example, a basic two channel instrument may give more amplification for high frequency versus low-frequency sounds if required based on the hearing test results. By contrast, premium technology hearing aids may have a lot more channels, and therefore offer a higher resolution of signal processing.
Basic hearing aids may be computer programmable but may have fewer or more limited adjustments available for fine-tuning and customization as compared to advanced technology. Today’s basic digital hearing aids offer the benefits of better hearing to many people with hearing loss.
Basic digital hearing aids also generally require you to make some manual adjustments in certain listening situations such as turning a volume control up or down, or pushing a button on the aids to reduce noise coming from behind.
The following are examples of features that are usually included in basic hearing aid technology.
Wireless technology allows two hearing aids to operate together as one complete system, instead of acting as two independent devices. The sound input to both hearing aids is shared and decisions about the digital sound processing are based on the combined information. This is known as binaural processing. This technology mimics the brain's ability to process information coming from both ears and helps reduce manual adjustments.
For example, if one hearing aid is being triggered for directional mode, both hearing aids would likely switch into that mode at the same time. The data transfer rates for wireless hearing aids are measured in nanoseconds, which is much faster than human brain can detect. For the wearer, the adjustments are perceived in real time. Sound processing is therefore synchronized between the two hearing aids, thus improving sound quality for the wearer.
A telecoil or t-coil is a wireless feature that picks up electromagnetic signals from harmonic telephones or looped rooms. This technology has been available in hearing aids for a very long time. Because the signal of interest is directed to the hearing aid’s processor without using the microphone, telecoil can improve the signal-to-noise ratio while eliminating the potential for feedback. Public performances, tours, exhibits and worship services are commonly made accessible to individuals with hearing loss via telecoil.
Frequency modulation (FM) compatibility is a wireless feature that enables hearing aids to connect with FM systems, sometimes via a special attachment to the hearing aids called a boot. FM systems can be used alone or with hearing aids. Like telecoil, FM systems improve the signal to noise ratio without causing a feedback loop in the hearing aids. FM compatibility is especially important when selecting hearing aids for children because these systems are commonly used in educational settings to ensure that the teacher’s voice is heard above the clamor of the classroom.
Digital noise reduction systems analyze the signal to determine if it contains unwanted noise. If this unwanted noise is detected, this system reduces the level of noise. This feature makes the background or environmental noise less annoying and boosts your listening comfort. Digital noise reduction has been shown to be effective and preferred by hearing aid wearers.
Similar in purpose to the digital noise reduction, impulse noise reduction improves listening comfort. This system detects any transient loud noises, such as car keys rattling, typing on a keyboard or dishes rattling, and softens them instantly.
Although fairly specific in its application, wind noise reduction can make a world of difference for those who spend time enjoying outdoor hobbies, like golfers and boaters. Wind noise reduction detects the impact of the wind blowing across the hearing aid microphones and avoids or reduces the amplification of it.
Data logging is a feature that stores data about the listening environments in which you wear your hearing aids and your preferences for programs, volume levels and other features. The information can be accessed by the hearing healthcare professional when you return for a follow-up appointment. Your practitioner may use this valuable information to further customize your hearing aid fitting.
Feedback management systems combat the inevitable feedback (whistling) that occurs in a hearing aid. These feedback loops create an annoying whistling sound that can get in the way of your comfort. Feedback management algorithms can be implemented differently for basic hearing aids or advanced hearing aids. Basic feedback management systems may reduce the overall amplification to remove the whistling. Advanced feedback management systems reduce or eliminate whistling without affecting overall amplification of the hearing aid.