Everyone has experienced how difficult it can be to carry out a phone conversation in a noisy situation. For hearing instrument wearers, using the phone can be very challenging even in quiet situations and impossible in the presence of any background noise. While the ability to use the phone may seem of secondary importance, phone use is an important communication medium to which everyone should have access. In fact, phone use has been linked to self-reported quality of life.
Numerous factors contribute to hearing instrument wearers’ experienced difficulties communicating on the phone. These include presence of background noise, inappropriate or inadequate coupling to the phone, handset positioning difficulties or constraints, and absence of visual cues.
Many hearing instruments have the option to operate in one of three modes for phone conversations: Acoustic phone, inductive coupling (telecoil), and digital wireless coupling.
Acoustic mode. Hearing instruments operating in acoustic mode (holding the phone receiver to the hearing instrument microphone) receive and amplify all sounds surrounding the hearing instrument wearer. Sounds amplified in this mode include the phone’s audio signal—typically conversational speech—as well as ambient sounds.
Telecoil. Hearing instruments operating via inductive coupling (telecoil) receive signals from magnetic fields generated by telecoil-compatible phones. Inductive coupling can be inductive coupling only, in which amplification of ambient sounds is avoided by turning off the hearing instrument microphones in the inductive coupling program (telecoil program). Inductive coupling can also be a combined inductive coupling and hearing instrument microphone mode (microphone-and-telecoil program) allowing the phone signal to be delivered through the inductive coupling while ambient sounds are being amplified through the hearing instrument microphones.
Wireless streaming. The third option for phone use is streaming either via a hearing aid accessory or directly from an iPhone. When streaming through a hearing instrument accessory, the accessory is paired to a Bluetooth compatible phone. When using the phone, the sound streams from the phone to the accessory, via Bluetooth, to the hearing instruments via another digital wireless technology.
As with inductive coupling, streaming from the phone can be done with and without the hearing instrument microphones activated, and thereby allow either amplification of or removal of ambient sounds. Inductive coupling and streaming improves the signal-to-noise ratio (SNR) by streaming the phone signal (typically speech). The degree of SNR improvement depends on the technology used and whether the hearing instrument microphones are activated or not. Deactivation of the hearing instrument microphones may be needed for some in order to be able to carry out a phone conversation, whereas activation of the hearing instrument microphones might be preferred by others to allow awareness of the environmental sounds around them.
Streaming, whether via an accessory, removes the reliance on correct placement of the phone handset. Streaming also allows the listener access to the phone conversation in both ears, which has been shown to provide significant benefit even in the presence of several different noise configurations. This benefit has been attributed to binaural summation (or binaural redundancy), and binaural squelch.
It is estimated that visual information makes up approximately two-thirds of all communication.3 Most of us are probably unaware of our usage of visual cues in many situations, but become aware of them when in challenging communication situations like in background noise. The absence of visual cues might be the reason why people with normal hearing periodically experience difficulties hearing on the phone when in background noise. The addition of visual cues is also helpful for people with hearing impairment. In fact, those with very severe losses rely as much or more on visual information as on auditory information.
One of the advances that have come with smartphones and tablets is the possibility to carry out video calls. This means that the camera on the smart device can be used to pick up and transmit an animated image of the face of the caller at the same time he or she is talking. In this way, the call recipient can both see and hear the caller.
Many different apps exist that can be downloaded to smart devices for video calling. They require that both the caller and call recipient are using the same app. Assuming that the same benefit of visual cues is available on a video call, this technology could provide an important benefit for hearing instrument users. In particular, for those with severe-to-profound hearing losses, this technology could make the difference between successful phone use and no phone conversation at all.