When as audiologists we ask someone if they are aware of their environment, we are not normally trying to find out if they recycle their glass bottles. What we want to find out is, with their hearing aids in, can they hear the sounds that surround them every day — for example, a dog barking, a passing car or children playing in the garden and can they localize where the sound is coming from? Without the ability to do this, the sense of just knowing where you are and what is going on around you can be lost. With hearing aids this ability to localize can sometimes be a challenge and complex algorithms are added as part of the hearing aid’s signal processing to essentially “put back” the pinna effect that has been lost by inserting an earpiece and placing a hearing aid behind the ear.Lyric is a different hearing aid concept and is also referred to as an extended wear hearing aid. It is an FDA-approved hearing aid for individuals with mild to moderately-severe hearing loss. By limiting the space between Lyric and the ear drum, the Lyric wearer can take advantage of important acoustic cues provided by the outer ear. This negates the need to design an algorithm to achieve this natural benefit. The placement of Lyric is 4mm from the eardrum and means that it can make use of the pinna, concha and the contours of the ear canal to retain the natural resonances created by the outer ear.
A recent independent study conducted by the Walter Reed National Military Center in the US evaluated, as part of their feasibility studies, the ability of Lyric to preserve localization cues due to deep insertion. Results were impressive when compared to the open ear. In their report, it was stated “to their knowledge this is the only active listening device that has ever been shown to preserve normal localization accuracy in a test of this type”.1 These positive results are also seen in other localization tests where, when Lyric localization is compared to the unaided ear and daily wear hearing aids, it provides better localization. It can be seen that less errors are made in terms of locating the sound source.2
This ability contributes to the natural listening experience that people expect with their hearing aids.
So when a patient is fitted with Lyric they are not going to turn into eco-warriors overnight but they will be able localize sounds just as the open ear does.
1 Brungart, D., McKenna, E., and Sherlock, L. (2015). Evaluation of extended-wear hearing aid technology for operational military use. Technical Report.
2 ten Holder, J. (2011). A comparison of Lyric with digital hearing aids: Proven to be equally effective. Phonak Field Study News.