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

Tanya L Arbogast, Brian C J Moore, Sunil Puria, Drew Dundas, Judith Brimacombe, Brent Edwards, Suzanne Carr Levy, Tanya L Arbogast, Brian C J Moore, Sunil Puria, Drew Dundas, Judith Brimacombe, Brent Edwards, Suzanne Carr Levy

Abstract

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.

Trial registration: ClinicalTrials.gov NCT02042404 NCT02470494.

Figures

Fig. 1.
Fig. 1.
Baseline air conduction thresholds measured through earphones for the ears analyzed in the current study: 80 ears in study 1 (left panel) and 69 ears in study 2 (right panel). See the last paragraph of the Procedures section for detail regarding participant data included in these analyses. The averages are represented by the thick solid black lines with error bars representing ±1 SD.
Fig. 2.
Fig. 2.
Illustration of the main components of the Earlens system.
Fig. 3.
Fig. 3.
The left panel shows mean output levels and thresholds for study 1 at the First Fit Adjusted time point. The maximum possible equivalent sound pressure output is indicated by the solid line near the top of the panel. Soft, moderate, and loud outputs are indicated by squares, circles, and triangles, respectively; open symbols/dotted lines indicate the prescribed (Rx) fit, and filled symbols/solid lines indicate the current (adjusted) fit. Pure-tone thresholds in dB SPL are indicated by the asterisks/dashed lines. The right panel shows the change in output between the first fit adjusted and 120-day time points (120-day minus First Fit Adjusted), with corresponding ±1 SD curves.
Fig. 4.
Fig. 4.
As Figure 3, but for the First Fit Adjusted (left panel) and change from First Fit Adjusted to 90-day (right panel) settings for study 2. Maximum equivalent sound pressure output (MPO) values are shown here as the dotted line with no symbols just below the maximum possible equivalent sound pressure output (MPPO) curve since the fitting software was changed to allow the MPO to be set below the MPPO for study 2.
Fig. 5.
Fig. 5.
As Figure 4, but for a subset of participants from study 2 with automatic acclimatization turned on. The change in current fit curves in the extended high frequencies between First Fit Adjusted and 90-day, largely reflects the change in output as a result of turning acclimatization on. By 90 days, the acclimatization was complete.
Fig. 6.
Fig. 6.
Insertion gain (IG) values for study 1 as a function of frequency for First Fit Initial settings. The dotted line shows the mean Cambridge Method for Loudness Equalization 2 - High Frequency (CAM2)-prescribed IG at compression threshold (IGCT). The solid squares, circles, and triangles show the mean current fit IGs for soft, moderate, and loud inputs, respectively. The open squares with four points and error bars show the mean functional gains ±1 SD, and the asterisks show the maximum functional gain for each frequency. Note that the sample size differs from that for the study 1 output graph; see text for explanation.
Fig. 7.
Fig. 7.
As Figure 6, insertion Gagin (IG) and functional gain values for study 2 as a function of frequency for First Fit Adjusted settings. The dotted line shows the mean CAM2-prescribed IG at compression threshold (IGCT). The solid squares, circles, and triangles show the mean current fit IGs for soft, moderate, and loud inputs, respectively. The open squares with four points and error bars show the mean functional gains ±1 SD, and the asterisks show the maximum functional gain for each frequency.
Fig. 8.
Fig. 8.
Comparison between CAM2-prescribed insertion gain at compression threshold (IGCT; dotted line), CAM2-prescribed inexperienced user IGCT (solid line), and the current fit IGCT (*) as a result of audiologist adjustment to the fitting at first fit.
Fig. 9.
Fig. 9.
Abbreviated Profile of Hearing Aid Benefit (APHAB) scores showing mean percent of self-perceived communication problems for each of the subscales. Light gray bars are for the unaided condition, medium gray bars are for the participants’ own hearing aids, and black bars are for aided with Earlens at the 90- or 120-day time point. The upper panel is for the comparison of Earlens to unaided listening while the lower panel shows data for the subset of participants with their own hearing aids. Error bars show ±1 SD. Asterisks indicate significant differences at p < 0.05 or p < 0.001.
Fig. 10.
Fig. 10.
Study 1 satisfaction ratings for the Earlens system on a 6-point Likert scale (shown on the y axis) at the 120-day time point for the categories specified along the x axis. The median rating is indicated by the open circles, and the 25th and 75th percentiles are indicated by the lower and upper edges of the boxes. The solid horizontal line in the center indicates the neutral mid-point of the rating scale. Note: the sound quality and speech in noise data were previously presented in a different format in Gantz et al. (2017).
Fig. 11.
Fig. 11.
As Figure 10, but for study 2 at the 90-day time point. Satisfaction ratings were obtained on a 5-point Likert scale, indicated on the y axis, for the categories assessed on the x axis. The neutral rating is marked by the solid horizontal line. Note: data presented in a different format in McElveen et al. (Reference Note 1).
Fig. 12.
Fig. 12.
Study 1 comparison ratings for Earlens relative to unaided listening (top panel) and relative to participants’ own hearing aids (lower panel). Ratings were obtained on a 5-point Likert scale, shown on the y axis, for the categories shown on the x axis. Median ratings are indicated by the open circles, and the 75th and 25th percentiles are indicated by the upper and lower edges of the boxes. The neutral mid-point of the rating scale is indicated by “No change” and the solid horizontal line. Note: the Quality of life comparison to unaided listening only (top panel) was previously presented in a different format in Gantz et al. (2017).
Fig. 13.
Fig. 13.
As Figure 12, but for study 2 at the 90-day time point. Satisfaction ratings were obtained on a 5-point Likert scale, indicated on the y axis, for the categories assessed on the x axis. The neutral rating is “About the same” and is marked by the solid horizontal line.

References

    1. Aazh H., Moore B. C. J. Dead regions in the cochlea at 4 kHz in elderly adults: Relation to absolute threshold, steepness of audiogram, and pure tone average. J Am Acad Audiol, 2007a). 18, 96–107.
    1. Aazh H., Moore B. C. The value of routine real ear measurement of the gain of digital hearing aids. J Am Acad Audiol, 2007b). 18, 653–664.
    1. Aazh H., Moore B. C., Prasher D. The accuracy of matching target insertion gains with open-fit hearing aids. Am J Audiol, 2012). 21, 175–180.
    1. Ahlstrom J. B., Horwitz A. R., Dubno J. R. Spatial benefit of bilateral hearing AIDS. Ear Hear, 2009). 30, 203–218.
    1. ANSI. (ANSI S3.5-1997. Methods for the Calculation of the Speech Intelligibility Index. 1997). New York, NY: American National Standards Institute.
    1. Baer T., Moore B. C., Kluk K. Effects of low pass filtering on the intelligibility of speech in noise for people with and without dead regions at high frequencies. J Acoust Soc Am, 2002). 112(3 Pt 1), 1133–1144.
    1. Bentler R. A., Niebuhr D. P., Johnson T. A, et al. Impact of digital labeling on outcome measures. Ear Hear, 2003). 24, 215–224.
    1. Bentler R. A., Pavlovic C. V. Transfer functions and correction factors used in hearing aid evaluation and research. Ear Hear, 1989). 10, 58–63.
    1. Best V., Carlile S., Jin C, et al. The role of high frequencies in speech localization. J Acoust Soc Am, 2005). 118, 353–363.
    1. Byrne D., Dillon H. The National Acoustic Laboratories’ (NAL) new procedure for selecting the gain and frequency response of a hearing aid. Ear Hear, 1986). 7, 257–265.
    1. Cornelisse L. E., Seewald R. C., Jamieson D. G. The input/output formula: A theoretical approach to the fitting of personal amplification devices. J Acoust Soc Am, 1995). 97, 1854–1864.
    1. Cox R. M., Alexander G. C. The abbreviated profile of hearing aid benefit. Ear Hear, 1995). 16, 176–186.
    1. Dawes P., Hopkins R., Munro K. J. Placebo effects in hearing-aid trials are reliable. Int J Audiol, 2013). 52, 472–477.
    1. Dawes P., Powell S., Munro K. J. The placebo effect and the influence of participant expectation on hearing aid trials. Ear Hear, 2011). 32, 767–774.
    1. Fay J. P., Perkins R., Levy S. C, et al. Preliminary evaluation of a light-based contact hearing device for the hearing impaired. Otol Neurotol, 2013). 34, 912–921.
    1. Fay J. P., Puria S., Steele C. R. The discordant eardrum. Proc Natl Acad Sci U S A, 2006). 103, 19743–19748.
    1. Freed D. J., Soli S. D. An objective procedure for evaluation of adaptive antifeedback algorithms in hearing aids. Ear Hear, 2006). 27, 382–398.
    1. Füllgrabe C., Baer T., Stone M. A, et al. Preliminary evaluation of a method for fitting hearing aids with extended bandwidth. Int J Audiol, 2010). 49, 741–753.
    1. Gantz B. J., Perkins R., Murray M, et al. Light-driven contact hearing aid for broad-spectrum amplification: Safety and effectiveness pivotal study. Otol Neurotol, 2017). 38, 352–359.
    1. Gatehouse S., Naylor G., Elberling C. Linear and nonlinear hearing aid fittings–1. Patterns of benefit. Int J Audiol, 2006a). 45, 130–152.
    1. Gatehouse S., Naylor G., Elberling C. Linear and nonlinear hearing aid fittings–2. Patterns of candidature. Int J Audiol, 2006b). 45, 153–171.
    1. Hogan C. A., Turner C. W. High-frequency audibility: Benefits for hearing-impaired listeners. J Acoust Soc Am, 1998). 104, 432–441.
    1. Hornsby B. W., Johnson E. E., Picou E. Effects of degree and configuration of hearing loss on the contribution of high- and low-frequency speech information to bilateral speech understanding. Ear Hear, 2011). 32, 543–555.
    1. Jensen L. B. Hearing aid with adaptive matching of input transducers. J Acoust Soc Am, 2004). 116, 2719.
    1. Keidser G., Dillon H., Flax M, et al. The NAL-NL2 prescription procedure. Audiol Res, 2011). 1, e24.
    1. Khaleghi M., Puria S. Attenuating the ear canal feedback pressure of a laser-driven hearing aid. J Acoust Soc Am, 2017). 141, 1683.
    1. Levy S. C., Freed D. J., Nilsson M, et al. Extended high-frequency bandwidth improves speech reception in the presence of spatially separated masking speech. Ear Hear, 2015). 36, e214–e224.
    1. Levy S. C., Freed D. J., Puria S. Characterization of the available feedback gain margin at two device microphone locations, in the fossa triangularis and behind the ear, for the light-based contact hearing device. J Acoust Soc Am, 2013). 134, 4062.
    1. Madsen S. M. K., Moore B. C. J. Music and hearing aids. Trends Hear, 2014). 18, 1–29.
    1. Moore B. C., Füllgrabe C., Stone M. A. Effect of spatial separation, extended bandwidth, and compression speed on intelligibility in a competing-speech task. J Acoust Soc Am, 2010a). 128, 360–371.
    1. Moore B. C., Füllgrabe C., Stone M. A. Determination of preferred parameters for multichannel compression using individually fitted simulated hearing AIDS and paired comparisons. Ear Hear, 2011). 32, 556–568.
    1. Moore B. C., Glasberg B. R. A revised model of loudness perception applied to cochlear hearing loss. Hear Res, 2004). 188, 70–88.
    1. Moore B. C., Glasberg B. R. Modeling binaural loudness. J Acoust Soc Am, 2007). 121, 1604–1612.
    1. Moore B. C., Glasberg B. R., Stone M. A. Development of a new method for deriving initial fittings for hearing aids with multi-channel compression: CAMEQ2-HF. Int J Audiol, 2010b). 49, 216–227.
    1. Moore B. C., Huss M., Vickers D. A, et al. A test for the diagnosis of dead regions in the cochlea. Br J Audiol, 2000). 34, 205–224.
    1. Moore B. C., Marriage J., Alcántara J, et al. Comparison of two adaptive procedures for fitting a multi-channel compression hearing aid. Int J Audiol, 2005). 44, 345–357.
    1. Moore B. C., Popelka G. R. Preliminary comparison of bone-anchored hearing instruments and a dental device as treatments for unilateral hearing loss. Int J Audiol, 2013). 52, 678–686.
    1. Moore B. C., Sęk A. Comparison of the CAM2 and NAL-NL2 hearing aid fitting methods. Ear Hear, 2013). 34, 83–95.
    1. Moore B. C., Sęk A. Comparison of the CAM2A and NAL-NL2 hearing-aid fitting methods for participants with a wide range of hearing losses. Int J Audiol, 2016a). 55, 93–100.
    1. Moore B. C. J., Sek A. P. Preferred compression speed for speech and music and its relationship to sensitivity to temporal fine structure. Trends Hear, 2016b). 20, 1–15.
    1. Moore B. C., Stone M. A., Alcántara J. I. Comparison of the electroacoustic characteristics of five hearing aids. Br J Audiol, 2001). 35, 307–325.
    1. Moore B. C., Stone M. A., Füllgrabe C, et al. Spectro-temporal characteristics of speech at high frequencies, and the potential for restoration of audibility to people with mild-to-moderate hearing loss. Ear Hear, 2008). 29, 907–922.
    1. Murray N., Byrne D. Performance of hearing-impaired and normal hearing listeners with various high-frequency cut-offs in hearing aids. Aust J Audiol, 1986). 8, 21–28.
    1. Plyler P. N., Fleck E. L. The effects of high-frequency amplification on the objective and subjective performance of hearing instrument users with varying degrees of high-frequency hearing loss. J Speech Lang Hear Res, 2006). 49, 616–627.
    1. Puria S. Measurements of human middle ear forward and reverse acoustics: Implications for otoacoustic emissions. J Acoust Soc Am, 2003). 113, 2773–2789.
    1. Puria S., Maria P. L., Perkins R. Temporal-bone measurements of the maximum equivalent pressure output and maximum stable gain of a light-driven hearing system that mechanically stimulates the umbo. Otol Neurotol, 2016). 37, 160–166.
    1. Rankovic C. M. An application of the articulation index to hearing aid fitting. J Speech Hear Res, 1991). 34, 391–402.
    1. Ricketts T. A., Dittberner A. B., Johnson E. E. High-frequency amplification and sound quality in listeners with normal through moderate hearing loss. J Speech Lang Hear Res, 2008). 51, 160–172.
    1. Scollie S., Seewald R., Cornelisse L, et al. The desired sensation level multistage input/output algorithm. Trends Amplif, 2005). 9, 159–197.
    1. Sęk A., Moore B. C. Implementation of a fast method for measuring psychophysical tuning curves. Int J Audiol, 2011). 50, 237–242.
    1. Simpson A., McDermott H. J., Dowell R. C. Benefits of audibility for listeners with severe high-frequency hearing loss. Hear Res, 2005). 210, 42–52.
    1. Skinner M. W., Miller J. D. Amplification bandwidth and intelligibility of speech in quiet and noise for listeners with sensorineural hearing loss. Audiology, 1983). 22, 253–279.
    1. Struck C.J., Prusick L. Comparison of real-world bandwidth in hearing aids vs Earlens light-driven hearing aid system. Hear Rev, 2017). 24, 24–29.
    1. Turner C. W., Henry B. A. Benefits of amplification for speech recognition in background noise. J Acoust Soc Am, 2002). 112, 1675–1680.
    1. Vickers D. A., Moore B. C., Baer T. Effects of low-pass filtering on the intelligibility of speech in quiet for people with and without dead regions at high frequencies. J Acoust Soc Am, 2001). 110, 1164–1175.
    1. Vinay, & Moore B. C. J. Prevalence of dead regions in subjects with sensorineural hearing loss. Ear Hear, 2007). 28, 231–241.
REFERENCE NOTE
    1. McElveen J. T., Gantz B. J., Perkins R. P, et al. High-frequency gain is better provided by a light-driven contact hearing aid: A comparative study. Laryngoscope.submitted.

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