Hearing aids are available in a variety of styles and in a range of sound processing technologies. Hearing aids styles refer to the "packaging" of the technology. What does the hearing aids look like? The tiniest hearing aids are called "completely-in-the-canal" (CIC) and are barely visible. Slightly larger are the canal and half-shell sizes, still small, but visible. Full shell (in-the-ear) hearing aids fill the bowl of the ear. Behind the ear instruments house the components in a unit that sits over the ear, and the sound is delivered to the ear through an ear mold or a narrow tube.
So, what about the hearing aid technologies, most hearing aids fit today have digital technology. Digital hearing aids function as miniature computers. This is a major breakthrough because much more sound processing is possible within a small space. The newer hearing aids offer far greater programming flexibility, and produce a crisper, cleaner sound. These hearing aids have the ability to analyze the acoustic environment and adjust the amplification accordingly. Speech is perceived more comfortably and clearly for many patients in a variety of sound environments.
Over the past few years, product lines have been expanded. Most manufacturers now offer a range of products from high end feature-rich hearing aids to mid-line instruments to entry level hearing aids that meet more basic needs.
Some of the features encountered in current hearing aids include, open fittings, these tiny behind the ear instruments with a narrow tube for bringing sound to the ear are a great new development for patients with mild or moderate high frequency hearing loss. They are cosmetically appealing, and acoustically 'transparent' so that sound is heard especially naturally with less perception of occlusion than traditional hearing aids. Digital technology's advances in feedback management makes this type of fitting possible.
The multiple memory feature allows the user to opt for different listening strategies optimized for a variety of listening situations. This feature is beneficial for people with active lifestyles who regularly encounter varying acoustic environments.
Newer hearing aids may offer "multi-channel adaptive directionality" which means that the hearing aid microphones continually respond to the speech and noise sources in the environment to provide the best possible signal-to-noise ratio for the listener. The goal of this feature is to preserve speech understanding in the presence of background noise.
The aspect of feedback management hearing aid users may now expect less likelihood of feedback (whistling). This is important because newer hearing aids can provide more audibility of soft sounds without feedback. Open fittings, which provide relief for occlusion, are also possible because of digital advancements in feedback management.
The newest algorithms for processing speech in the presence of noise not only promote more comfortable listening, but aim to preserve speech intelligibility.