All technology connecting hearing instruments to sound sources or other people has one major functional goal–to improve the signal to noise ratio making speech easier to discriminate especially in the presence of background noise. Contemporary hearing instruments offer such connectivity through wireless streaming and wireless accessories.
ReSound’s Charlotte Jespersen, M.A., and Brent Kirkwood, Ph.D., presented information about available wireless options at the 2013 AudiologyNOW! conference.
First, the term “wireless” covers a multitude of technologies for transmitting information for many different purposes without the use of wires. Early wireless solutions included telecoils, infrared systems and frequency modulation (FM) systems. Today’s digital wireless solutions are:
- Near Field Magnetic Induction (NFMI + Bluetooth RF) – contain transmission energy within the localized magnetic field. Current hearing aids incorporate Bluetooth through an adaptor or gateway device. Advantages include ease of implementation due to existing RF chips, longer battery life when using wireless function, easy transmission through the head and stable performance for near-field part transmission. Drawbacks include short transmission distance, need of gateway device which can introduce delay and possibility to encounter interference with magnetic sources.
- Proprietary radio frequency (RF)+ 2.4 GHz Wireless Technology – use a radio to generate an electrical wave and an antenna to send the information, “far-field”. Advantages include no gateway device, long distance signal transmission, low latency, robust, reliable and frequency-band approved worldwide. Drawbacks include requirement of a specially designed antenna, streaming device for Bluetooth connectivity and higher current drain when using wireless functions.
Who can benefit from wireless accessories? In the case of a TV Streamer, any patient who struggles to understand what is being said without closed captioning activated on their TV set as well as any patient who enjoys listening to music and lacks fidelity with the hearing instruments alone. TV Streamers are not as useful for mild hearing losses. The external microphone can benefit patients who attend talks, seminars or church services where the speaker is at a distance. Patients who need sound enrichment to combat tinnitus can also benefit from an external microphone. The phone streamer can benefit any patient with a Bluetooth enabled phone who experiences difficult understanding speech on the phone when using other methods.