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Achieved Gain and Subjective Outcomes for a Wide-Bandwidth Contact Hearing Aid Fitted Using CAM2

Arbogast, Tanya L.1; Moore, Brian C. J.2; Puria, Sunil3,4; Dundas, Drew1; Brimacombe, Judith1; Edwards, Brent1,5; Carr Levy, Suzanne1

doi: 10.1097/AUD.0000000000000661
Research Article: PDF Only

Objectives: The objective of this study was to test the ability to achieve, maintain, and subjectively benefit from extended high-frequency amplification in a real-world use scenario, with a device that restores audibility for frequencies up to 10 kHz.

Design: A total of 78 participants (149 ears) with mild to moderately-severe sensorineural hearing loss completed one of two studies conducted across eight clinical sites. Participants were fitted with a light-driven contact hearing aid (the Earlens system) that directly drives the tympanic membrane, allowing extended high-frequency output and amplification with minimal acoustic feedback. Cambridge Method for Loudness Equalization 2 - High Frequency (CAM2)-prescribed gains for experienced users were used for initial fitting, and adjustments were made when required according to participant preferences for loudness and comfort or when measures of functional gain (FG) indicated that more or less gain was needed. Participants wore the devices for an extended period. Prescribed versus adjusted output and gain, frequency-specific FG, and self-perceived benefit assessed with the Abbreviated Profile of Hearing Aid Benefit, and a custom questionnaire were documented. Self-perceived benefit results were compared with those for unaided listening and to ratings with participants’ own acoustic hearing aids.

Results: The prescribed low-level insertion gain from 6 to 10 kHz averaged 53 dB across all ears, with a range from 26 to 86 dB. After adjustment, the gain from 6 to 10 kHz decreased to an average of 45 dB with a range from 16 to 86 dB. Measured FG averaged 39 dB from 6 to 10 kHz with a range from 11 to 62 dB. Abbreviated Profile of Hearing Aid Benefit results revealed a significant improvement in communication relative to unaided listening, averaging 28 to 32 percentage points for the background noise, reverberation, and ease of communication subscales. Relative to participants’ own hearing aids, the subscales ease of communication and aversiveness showed small but significant improvements for Earlens ranging from 6 to 7 percentage points. For the custom satisfaction questionnaire, most participants rated the Earlens system as better than their own hearing aids in most situations.

Conclusions: Participants used and reported subjective benefit from the Earlens system. Most participants preferred slightly less gain at 6 to 10 kHz than prescribed for experienced users by CAM2, preferring similar gains to those prescribed for inexperienced users, but gains over the extended high frequencies were high relative to those that are currently available with acoustic hearing aids.

This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1Earlens Corporation, Menlo Park, California, USA;

2Department of Experimental Psychology, University of Cambridge, Cambridge, United Kingdom;

3Department of Otology & Laryngology, Harvard Medical School, Boston, Massachusetts, USA;

4Eaton-Peabody Laboratory of Auditory Physiology, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts, USA; and

5National Acoustic Laboratories, Sydney, Australia.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and text of this article on the journal’s Web site (

ACKNOWLEDGMENTS: The authors express their appreciation to the study participants, to the Clinical Investigators who treated and counseled the participants and collected the study data, and to Tim Streeter for assistance with fitting software data extraction and analysis. The research was partially supported by SBIR Phase IIB grant R44 DC 08499 from the National Institute on Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health. Portions of the data in this article were presented at the International Hearing Aid Research Conference (IHCON), Tahoe City, CA, August 10–14, 2016. Results from three Earlens Patient Satisfaction questions from study 1 were presented in a different format in Gantz et al. (2017). For study 2, functional gain, APHAB, and patient satisfaction results were presented for a different purpose or different format in McElveen et al. (Reference Note 1).

This work was funded in part by SBIR Phase IIB grant R44 DC 08499 from the NIDCD of NIH. Remaining funding provided by Earlens Corporation.

The authors are/were employed by or are consultants for Earlens Corporation, manufacturer of the Light-Driven Contact Hearing Aid.

Presenting data for clinical trials registered at NCT02042404/NCT02470494.

Address for correspondence: Tanya L. Arbogast, Clinical Research, Earlens Corporation, 4045A Campbell Avenue, Menlo Park, CA 94025, USA. E-mail:

Received November 1, 2017; accepted August 7, 2018.

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