Better Hearing and Sound Quality with Lyric Hearing Aids
Unlike other hearing aids, Lyric® is placed deep into the bony portion of the ear canal so that the receiver resides approximately 4 mm from the ear drum and the microphone is ≥4 mm from the opening of the ear canal. This placement deep in the ear canal provides a number of sound quality benefits. In fact, in a recent user survey, 91% of users are very satisfied with Lyric's sound quality.1
Benefits of Deep Canal Placement for hard of hearing patients:
Improved Directionality and Localization (ability to tell where sounds are coming from)
Lyric’s placement deep in the ear canal allows the pinna (outer part of the ear) to interact naturally with incoming sounds. The acoustic transformations produced by the pinna as sound enters the ear canal contribute to the ability to accurately determine where sounds are coming from in the environment.2,3 This ability contributes to the perception of natural hearing and is key to organizing multiple sound sources in space (e.g., several people talking at the same time) in order to selectively attend to the source (talker) of interest.4,5
Minimized Occlusion Effect (blocked feeling in the ear canal)
Lyric’s design and placement allow it to reside deeper in the bony portion of the ear canal than traditional hearing aids, thus minimizing the occlusion effect. The occlusion effect occurs with hearing aids because sound that causes vibrations in the ear canal cannot escape out the open end of the ear canal; the sound gets trapped by the hearing aid and instead travels toward the ear drum. Hearing aids that fit deep in the ear canal, extending into and making contact with the bony portion of the canal, reduce the vibrations that cause the occlusion effect relative to standard-length hearing aids.6,7
Reduced Feedback (whistling sound hearing aids can make)
Deep placement of a hearing aid, such as with Lyric, has been shown to reduce feedback for several reasons:8
- The receiver sits closer to the ear drum than with traditional hearing aids, thereby requiring less output to accommodate comparable degrees of hearing loss, which decreases the chance of feedback occurring.
- The reduction of the occlusion effect due to the deep canal placement of Lyric eliminates the need for large vents needed with traditional hearing aids. Thus there is one less pathway for sound to leak out and for feedback to occur.
- Less high-frequency amplification between 2000-3000 Hz is required at the output of the hearing aid, which is the frequency range that most commonly contributes to feedback.
- Lyric resides predominately in the hard-walled bony portion of the ear canal. Because less of Lyric lies in the cartilaginous portion of the ear canal as compared to traditional hearing aids, there is less opportunity for the device to move and create a gap between the canal and the device around which sound can escape and produce feedback.
- Lyric is anchored in the ear canal with two soft, compliant “seals” that conform to irregular shapes and contours of various ear canals, even when the ear changes shape during chewing and talking. This prevents slippage of the device which, with traditional hearing aids, causes gaps to form between the aid and the canal wall resulting in sound leakage and feedback.
- Deep placement of a hearing aid, such as with Lyric, has been shown to reduce feedback for several reasons:8
High-Frequency Gain (ability to hear high pitched sounds)
Deep canal fittings such as with Lyric result in an increase in sound pressure level at the ear drum. This increase can be up to 15dB in the high frequencies and is caused primarily by a combination of two factors:9
- Reduced residual ear canal volume between the receiver and the ear drum
- The microphone location deeper in the ear canal allowing for pinna effects
- Additional Advantages
- Security of fit and retention
- Comfort: 94% of Lyric users rate Lyric’s comfort as better than their prior hearing aids10
- Reduction of wind noises
- Ability to use ear-level listening devices, such as a telephone, headphones, or stethoscope, with little to no feedback
1. Based on a telephone survey of 100 patients who have used Lyric for at least 30 days.
2. Blauert, J. (1997). Spatial Hearing: The Psychophysics of Human Sound Localization. MIT Press, Cambridge, MA, p. 63.
3. Langendijk, E.H.A. and Bronkhorst, A.W. (2002). Contribution of spectral cues to human sound localization. Journal of the Acoustical Society of America, 112, 1583-1596.
4. Cherry, E. (1953). Some experiments on the recognition of speech, with one and with two ears. Journal of the Acoustical Society of America, 25, 975-979.
5. Kidd, G. Jr., Arbogast, T.L., Mason, C.R. and Gallun, F.J. (2005). The advantage of knowing where to listen. Journal of the Acoustical Society of America, 118, 3804-3815.
6. Killion, M.C., Wilbur, L. and Gudmundsen, G.I. (1988). Zwislocki was right… A potential solution to the “hollow voice” problem (the amplified occlusion effect) with deeply-seated earmolds. Hearing Instruments, 39, 14-18.
7. Mueller, H.G., Bright, K.E. and Northern, J.L. (1996). Studies of the hearing aid occlusion effect. Seminars in Hearing, 17, 21-32.
8. Staab, W. (1996). Introduction to deep canal principles. Seminars in Hearing, 17, 3-19.
10. Based on the combination of results from two surveys totaling 47 patients who had used Lyric for at least 30 days.
*Satisfaction rating data based on a survey given to 68 clinical research patients after 30 days of using the Lyric device. The survey asked patients to rate various aspects of their device based on 5 choices, ranging from “Very Dissatisfied” to “Very Satisfied.” This data reflects the percentage of patients who rated their Lyric experience as “Satisfied” or “Very Satisfied.” N=68 patient responses for all categories except N=112 individual ear responses for “Comfort.” Data on file at InSound Medical, Inc.