Benefits of Direct Sound Transmission
Patients considering a bone anchored solution for their hearing loss have many options. As clinicians begin the process of discussing patient choices there are many factors patients often consider, including sound processor style, surgical features, wearing comfort, and cosmetic appeal. However, the candidate often overlooks or undervalues intangible benefits. These benefits relate to the importance of a solution that provides clarity of the signal without distortion or feedback, ample amount of power output to overcome the hearing loss and a broad frequency response to capture all of the acoustic elements important for the understanding of speech.
Bone anchored hearing devices can be placed into two broad categories: either they deliver sound via Skin Transmission, where the vibrating unit is placed on top of the skin and the sound vibrations have to pass through the skin and are attenuated before they reach the bone or via Direct Sound Transmission, with sound vibrations going directly to the bone and then on to the inner ear. Skin Transmission solutions are non-surgical options (e.g., a softband) versus Direct Sound Transmission percutaneous solutions, where the processor sends sound information through the skin to an implanted vibrating unit in direct contact with the bone.
Is there a difference between these two solutions?
Clinical evidence comparing patient outcomes between a skin transmission device and a direct transmission device indicates there is a significant difference. It has been shown that hearing thresholds obtained with Direct Sound Transmission solutions are about 5-20 dB lower (better) between 600 and 6000 Hz and speech reception thresholds are also 4-7 dB lower (better) than with conventional devices (Håkansson et al., 1984; Verstraeten et al., 2009). Beyond this fact, research shows that by choosing Direct Sound Transmission, such as a Ponto percutaneous solution, recipients can learn faster and remember more Pittman (2019) and Lunner et al. (2016) found that using Direct Sound Transmission can increase the learning speed in children by 2.5 times and improve recall abilities by 13 percent in adults.
It is widely established that children with a hearing loss have a reduced vocabulary compared to normal-hearing children (Blamey et al., 2001; Pittman et al., 2005). Hearing solutions for children with a hearing loss should help to close this gap. This is why the results seen by the Andrea Pittman (2019) study are so significant. The Pittman study is the first to show the influence of different sound transmission pathways on the essential domain of auditory learning with the effects of Direct Sound Transmission clear – children learn new words faster.
It has been shown that adults with hearing loss use many additional cognitive resources to recognize, listen to and process sounds. One of these cognitive resources is our working memory. Working memory can be used for both processing and storing information. Thus if more resources are used for processing, fewer resources are left for storage. In fact the ability to remember information can be used as an estimate of how many resources are left for storage, and how effortful it was to process that signal. Lunner and colleagues (2016) compared the ability to remember information using Ponto connected to either a softband (Skin Transmission) or an abutment (Direct Sound Transmission). Their results showed that the Ponto users’ recall ability was significantly higher with the sound processor connected to the abutment (52%) as compared to the Softband solution (46%). These findings suggest that transmitting the sound via Direct Sound Transmission to the temporal bone without skin dampening yields better signal quality and less effortful processing.
To summarize, the Ponto System uses Direct Sound Transmission, allowing for the most efficient transmission of speech and sounds via the skull bone directly to the cochlea without skin dampening. With the most powerful abutment-level sound processors available on the market, we can provide access to a larger range of everyday sounds with less distortion.
We believe that counseling on the benefits of a system beyond what is concrete to the patient will impact their future hearing outcomes and contribute to their overall quality of life. So, moving patients from softband to an abutment should include discussion of the advantages of Direct Sound Transmission.
To learn more about the benefits of direct sound transmission, we encourage you to register for our upcoming training on March 24, 2021 or reach out to your regional clinical specialist.
About the Author
Carissa Moeggenberg is an audiologist who has worked in the hearing healthcare field for the past 28 years. She is presently the Training Manager for Oticon Medical.
Blamey, P. J., Sarant, J. Z., Paatsch, L. E., Barry, J. G., Bow, C. P., Wales, R. J., Wright, M., Psarros, C., Rattigan, K., Tooher, R. (2001). Relationships among speech perception, production, language, hearing loss, and age in children with impaired hearing. Journal of Speech, Language, and Hearing Research 44: 264–285. Håkansson, B., Tjellstrom, A., Rosenhall, U. (1984) Hearing thresholds with direct bone conduction versus conventional bone conduction. Scand Audiol 13: 3-13. Lunner, T., Rudner, M., Rosenbom, T., Ågren, J., and Ng, E.H.N. (2016) Using Speech Recall in Hearing Aid Fitting and Outcome Evaluation Under Ecological Test Conditions. Ear Hear 37 Suppl 1: 145S-154S. Pittman, A. L., Lewis, D.E., Hoover, B.M., and Stelmachowicz, P. G. (2005). Rapid word-learning in normal-hearing and hearing-impaired children: Effects of age, receptive vocabulary, and high-frequency amplification. Ear Hear 26: 619–629. Plack, C. J. (2005). The sense of hearing. Pittman, A. L. (2019) Bone conduction amplification in children: Stimulation via a percutaneous abutment vs. a transcutaneous softband. Ear Hear. Verstraeten, N., Zarowski, A. J., Somers, T., Riff, D. and Offeciers, E. F. (2009). Comparison of the audiologic results obtained with the bone anchored hearing aid attached to the headband, the testband, and to the “snap” abutment Otol. Neurotol 30: 70-75.