Keeping up with the Jones’ The changing criteria for hearing aid candidacy
Doesn’t it make you feel all warm and SNUGGIE? We know that 95% of those with SNHL can be helped with digital hearing aids * 90% of hearing aids in use are digital * Directional mics can improve understanding in noise * 9 out of 10 hearing aid users report improved quality of life * We also can confidently select the appropriate amplification for our patients based on audiometrics, lifestyle and needs *Better Hearing Institute
Mild to Moderately- Severe SNHL What would you select for this loss?
Mild to Moderately- Severe SNHL Now what would you do? 47 yom Wants wireless Hands free Smallest available High tech
What if you knew that… This same patient cannot focus to understand conversations in a crowded bar restaurant? Misses a lot of her manager’s instructions at big group meetings when he is at the front of the room? Can hear but not understand when her daughter whispers to her?
Even with a mild hearing loss… May cause you to miss 25-40% of the speech signal Reduced clarity since the brain is receiving some sounds but not all of the information Problems understanding someone farther away than a normal distance for conversation –Or even up close if the background environment is noisy Weak voices are also difficult to understand for people with mild hearing losses.
Oh, the possibilities! And so it seems, the criteria for candidacy based on audiogram has changed drastically! Why is this so exciting to our field? We can now address needs that could previously not be met: –Mild high-frequency loss, with subjective complaints –Mild high-frequency loss presenting with tinnitus –Normal to mild SNHL presenting with Auditory processing isense, open fit –Assymetry with normal ear Alternatives to CROS
Evidence Based Practice Evidence does not yet exist to support all the management decisions that an audiologist must make upon identifying minimal or mild bilateral hearing loss or unilateral hearing loss McKay S, Gravel JS, Tharpe AM. Amplification considerations for children with minimal or mild bilateral hearing loss and unilateral hearing loss. Trends Amplif. 2008 Mar;12(1):43-54. Review.
Fitting a mild high frequency hearing loss As a profession, we tended to “shy-away” from fitting this degree of hearing loss; WHY? –Concerned about over amplifying –Nothing available—ITE would provide the least amount of gain, however add 20dB+-- primarily related to the shell, not whats inside If you open up for comfort…there is risk for feedback! –Don’t need a hearing aid for their loss and associated problems –Will they hear the circuitry?
Concerns about over-amplifying Now that WDRC is possible, there is less worry for over amplifying with a mild loss, as soft sounds will be made audible and loud will be made tolerable. However, there is something to be said for giving more gain than needed that can add to the annoyance factor of wearing hearing aids—especially in the lows where there is already a tendency to feel “plugged up” for those with even moderate levels of SNHL.
The Good Ol’ OE Enhanced SPL of signal is trapped in the residual cavity of the ear canal, which makes its way to the inner ear via bone conduction von Bekesy indirectly talked about the hearing aid OE in his 1960 book, Experiments in Hearing, where he states, “For maximally useful hearing, it is important to reduce not only the sounds of vocalization but also noises produced by chewing, swallowing, and the like. Even walking produces vibrations of the body that can be heard if the auditory meatus is closed...”
Lybarger (1980) – effects of SAV vents on low-frequency response
Occluded Response Varies based on vent size: –Average OE is 12-16dB in range of 200-1000 Hz –Range from 5-8dB, up to 25-30dB
Open fits have changed our field more than we realize. Not only are they able to address hearing losses and needs we previously had no options for such as the case with a mild hi-Hz loss…. They have also: Forced the industry to improve hearing aid technology in order to meet the demanding needs of an open fitting Allow for easy access with same day fits –Benefits and drawbacks of demo-ing Impacted our numbers by changing purchasing trends –Average age of first-time user is 8 years younger* –BTE sales are on the rise, while custom product sales have decreased
What features have digital hearing aids allowed? Directional microphones Noise canceling Improved feedback management Automatic switching
Do your patients report lack of satisfaction with hearing aid use in one of the following listening situations: Small Groups Large Groups Places of Worship Watching TV In a Restaurant Riding in a Car In noisy situations
Directional hearing aids Improve the signal-to-noise-ratio (SNR) of speech occurring in a noisy background. Directional microphones are the only "hearing aid option" proven to improve speech understanding in noise. Other technologies (FM systems, direct audio input, assistive listening devices, etc.) can improve the SNR further.
Performance in noise with slim tubes–omni versus digital SurroundZoom microSavia dSZ -6 -5 -4 -3 -2 0 1 SNR in dB Unaidedomni Speech recognition in noise Decreased performance in omni Improved performance in dSZ Average SRT in noise for 20 subjects with sloping High-frequency SNHL Phonak in-house study
Valente, M. and Mispagel, K. Unaided and Aided performance with a directional open fit hearing aid. International Journal of Audiology. Volume 47, Number 6, June 2008, pp. 329-336(8) 26 new-users Fitted bilaterally After 4 weeks collected objective & subjective measurements Procedure: –Differences in performance between unaided and aided, and omni and directional were assessed –Measured RTS using HINT –HINT presented at 0º azimuth, with restaurant noise constant at 65dBA presented via 8 loudspeakers 45 degrees apart –Measured subjective report via APHAB Results: –Significant differences in RTS b/w directional and omni, and directional and unaided—suggests a patient would require directional mics in order to perform significantly better than unaided
Digital Noise Reduction Benefit: comfort, ease of listening for low level ambient noises Work well in steady-state noise (car, fan,..) Minimal improvement in speech intelligibility
Digital Noise Reduction Mueller, G., Weber, J., Hornsby, B. The Effects of Digital Noise Reduction on the Acceptance of Background Noise. Trends in Amplification, Vol 10, No.2, 83-93 (2006). 22 adults fit with 16-ch WDRC instruments with DNR processing Collected data on speech intelligibility (HINT) and acceptable noise level (ANL) with DNR on and DNR off Significant improvement for the ANL with DNR on, no significant improvement in HINT performance Suggests improved ease of listening for speech-in-noise situations
Feedback Improved feedback cancellation systems Allow for high-frequency gain to be preserved or increased when vent size is increased in an effort to minimize occlusion Practical limitation in the range of 30dB max stable high-Hz gain for unoccluded earmolds used with open fit devices
Automatic operation within hearing devices In quiet situations a directional mic has the disadvantage that sounds from behind are not heard as easily as sounds from the front. For hearing aid users to gain the most benefit from a conventional directional mics they must be able to correctly identify appropriate listening situations. The responsibility for manually switching between omni an directional in a hearing aid to suit listening environments requires not just physical skills from cognitive ones as well. Automatic operation of directional mics eliminate the need for manual switching
Open fit programming for demonstration Ensure kneepoints are high in low-frequencies for comfort; while keeping them low in the high-frequencies for clarity Increase mid-level gain overall Engage digital noise reduction in quiet setting for annoying ambient noises such as AC vent or computer running Present background noise behind patient, demonstrate differences between omni and directional settings by switching between the 2 in the software, this achieves 2 things: –They hear the difference and improvement with SIN –They learn the hearing aid will perform this switch automatically!
Thin Tube Mini-BTE Survey Sergei Kochkin, Ph.D. September 11, 2006
Likelihood of purchasing hearing aid in absence of thin tube Mini-BTE 22% would not have purchased anything Would have been fit instead with: –BTE (12%) –Mini-BTE (14%) –ITE (7%) –ITC/CIC (46%)
Does the thin tube BTE product result in more people seeking a hearing solution? The evidence in favor of more people seeking a hearing solution due to the availability of the thin-tube BTE; –Lower age of new users by 9 years –Increased new user rate by 29% points –1 in 5 consumers are reported to have rejected all other hearing aid styles in the absence of the thin-tube BTE.
Conclusions The appeal of the product is primarily due to improvements in occlusion, sound quality, fit and comfort and perceptions of benefit. In MarkeTrak VIII we will use a nationally representative sample of hearing aid consumers to confirm that: –more people seek a hearing solution if a thin-tube BTE is available. –that satisfaction increases with the use of this product category.
Mild Hearing loss presenting with Tinnitus Clinical evidence shows that the use of hearing aids in tinnitus patients provides two benefits: –It makes the patient less aware of the tinnitus –It improves communication by reducing the annoying sensation that sounds and voices are masked by the tinnitus Out-dated alternatives: –Sound machines-would need to carry around, so could become extremely cumbersome and only offer constant reminder of reason for need M I Trotter and I Donaldson (2008). Hearing aids and tinnitus therapy: a 25-year experience. The Journal of Laryngology & Otology, 122, pp 1052-1056 Del Bol, L & Ambrosetti, U. 2007. Hearing Aids for the Treatment of Tinnitus. Prog Brain Research. 166:341-5.
Normal to mild SNHL with Auditory Processing Disorders The use of mild-gain, open-ear fitting hearing aids with a directional microphone and noise reduction algorithm may be attempted on some children with APD on a trial basis.
Mild high-frequency hearing loss 60 yof Social worker Known mild high-frequency hearing loss, was tested 5 years ago c/o difficulty communicating with girlfriends at get- togethers, at work in the courtroom, and when out at restaurant/bars Husband is insistent she do something! She chose micro Exelia Art, and is doing well with reports of natural sound quality and improved understanding at wine get-togethers!
Asymmetry with normal ear 38 yof Left ear: profound SNHL; Right ear: normal HL c/o difficulty focusing in a group at work, understanding partner at a bar/restaurant Did not like the look of the CROSLink, although she did appreciate the sound quality Alternative options: –Micro fitting on good ear –Isense with Smartlink transmitter for work and socializing –Naida on corner audio ear She chose the versata micro for her right ear, and reports tremendous improvement at work and when socializing.
Wrap-Up Now we can address the needs of the patient with mild hi- Hz SNHL suffering from difficulty hearing in noise by fitting with an open-fit device. This approach achieves many tasks at once! Specifically: 1.Applying gain only where needed 2.Applying features to improve understanding in noise and reduce feedback 3.Reduces occlusion effect 4.Instant fit!
References Fabry, D. May 2006. Facts vs. Myths: The skinny on slim- tube open fittings. The Hearing Review. 20-26. Mueller, G., Weber, J., Hornsby, B. 2006. The Effects of Digital Noise Reduction on the Acceptance of Background Noise. Trends in Amplification, Vol 10, No.2, 83-93. Mueller, G. & Ricketts, T. November 2006. Open-canal fittings: Ten take home tips. The Hearing Journal. 24-39. Sandin, R. Textbook of hearing aid amplification, Valente, M. and Mispagel, K. June 2008. Unaided and Aided performance with a directional open fit hearing aid. International Journal of Audiology. Volume 47, Number 6, 329-336(8)