Publish Date : 2022-02-12 03:48:31
Modern hearing aids, particularly Lithium-Ion rechargeable models, have all been designed to resist moisture and dust. They generally are rated IP67 or IP68, meaning they are essentially impervious to dust and can withstand splashes and even submersion in up to 3 feet of water for several minutes. While not technically “waterproof,” they can hold their own in the gym or humid climates.
Nearly all ITE, RIC, and BTE and some CIC hearing aids can connect wirelessly to external devices, collectively called accessories. The idea is to overcome the challenges of distance, reverberation and background noise by capturing the desired signal (speech, music, TV, etc.) in an ideal condition, and beam it to the hearing aids across distances ranging from 30 to 80 feet depending on the wireless technology. Wireless hearing aid accessories fall into a few categories.
These small devices clip onto the speaker of interest and capture their speech at an SNR of up to +24 dB. This optimized signal is then beamed to the hearing aids so that regardless of the SNR of the room, you hear as if your hearing aid is as close to the speaker as your remote microphone. Most of the current remote microphones can sense their position and automatically adjust the microphone sensitivity. They range in price from a few hundred to over a thousand dollars but make a significant difference. In my practice, I demonstrate and measure the effect of remote microphones for anyone with an SNR loss on the Quick SIN over 10 dB.
Hearing well on the television depends on the size and shape of the room, whether you've updated the shag carpet you installed in the 70s, the quality of the speakers, and the recording quality of the program. A media streamer neutralizes all these variables by taking a direct, hard-wired audio signal from the TV or cable box (RCA or Digital TOSLink) and then beaming that signal to the hearing aids, just like the remote microphone. Most are easy to set up, and once they are, they either automatically connect, or you just tap a button on the hearing aid or use a smartphone app to activate streaming.
Even the largest hearing aids have small buttons. Those with wireless capability offer the option to control volume, programs for different listening situations, and streaming using either a smartphone app or a dedicated remote control. The stand-alone remote controls are usually the size of a key fob, and they either use a long-life watch type battery or are rechargeable.
Almost all wireless hearing aids offer a smartphone app. These apps are generally available on both Apple (iOS) and Android platforms and are provided free from the manufacturer. In addition to basic hearing aid controls like volume and program selection, some apps offer geotagging. This functionality serves two purposes. First, it allows you to fine-tune the hearing aids and accessories in specific settings, like your favorite bistro, then have them automatically go to those settings every time you walk in the door. Secondly, geotagging allows the app to “find” a misplaced hearing aid.
This technology is quite old, making its first appearance in hearing aids in the 1930s. Telecoils are electromagnetic receivers that pick up sound transmitted from hearing aid compatible telephones and special public address systems called “hearing loops.” Hearing loops are becoming more popular around the U.S., and using them provides the same benefit as a remote microphone without having to clip anything on the presenter. Telecoils are recommended in all hearing aids by the Hearing Loss Association of America8 and are so effective that several states require a signature indicating that a discussion of them occurred during your hearing aid consultation.
If a hearing aid can use wireless accessories, it probably also can stream directly from your iPhone, iPad, etc. All of the “big 6” provide at least one “made for iPhone” option, and Phonak has a way to also connect to Android devices in their Marvel line of products. Direct streaming uses the Bluetooth LE technology and can enhance your ability to understand on the telephone, but also to hear anything on that device better, such as streaming media (YouTube, Netflix, etc.) and alerts.
Hearing aids will generally advertise how many “channels” they have. Think of these like a graphic equalizer on a high-end stereo. It seems logical that more channels will provide a better match to your hearing, but it really depends. The number of channels is less important than the location of those channels compared to the shape of your audiogram since the fitting is based on that curve. If you have a gently sloping loss, a device with 8 or 10 channels might be fine. If your loss steeply drops off in the higher pitches, more channels will allow the fitter to match that curve better.
Everyone, even those with perfect hearing, has more difficulty understanding speech in background noise. Directional microphones lessen that difficulty somewhat. The degree to which directional microphones allow you to hear successfully in noise depends on the amount of difficulty you have (as shown on your Quick SIN test) and the level of noise in the environment. The difference between the loudness of speech and noise is called Signal-to-Noise Ratio (SNR) and is measured in deciBels (dB). The very best directional microphone systems available on hearing aids can improve SRN by about 15 dB. If the SNR of the room is -20 (room noise is 20 dB louder than speech), then the SNR reaching your brain will still be -5. If your Quick SIN SNR loss is 2 dB, then you're golden. If your SNR loss is 10 dB, then you are still 5 dB in the hole and will struggle even though the hearing aids are performing as designed.
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