In the Fall of 2010, I was approached after class by Josh Spann, one of my Au.D. students at the University of Arkansas for Medical Sciences. In class, we had been talking here and there about various Apple and Android apps that might help us understand audiology instrumentation. In particular, we were playing with sound level meter and spectrum analyzer apps. Josh, being an Apple product buff, asked me if I would be interested in purchasing an iPad that had just recently come out; however, when he asked it was more like a challenge or dare. His exact words: “I’ll buy one if you do.” I agreed, though my only prior experience with Apple products was an iPod I received for Christmas in 2008.
Our individual purchases led us both down an interesting path on dreaming up ways to incorporate the iPad (and other handheld touch-screen devices such as iPhone, iPod Touch, and Android smartphones) into the audiology clinic. It wasn’t long before we each discovered that a number of app developers were taking advantage of the Apple and Android platforms to create amplifiers that mimic hearing aids. By our last count (as of May 2012), there were 17! Earlier this year, Josh, Jason Johnson (another Au.D. student) and I downloaded 12 apps from the Apple Store and we collectively rated them and performed electroacoustic analyses (EAA) to see what their respective maximum OSPL90 levels were at the highest volume setting. Though the study and various permutations are still underway as part of Josh’s Au.D. Capstone Research project, I’m happy to share with you some of the information we wrote in a consumer article for the Hearing Health magazine (Atcherson et al., 2012) and presented in an invited Featured Session at the 2012 AudiologyNOW! convention in Boston (Atcherson & Spann, 2012). Our interest in the output of amplifier apps is not limited to the iPad, however. We are systematically evaluating some different Apple and Android products. For this blog, I’ve added for good measure three recently discovered Apple apps and two Android apps I found as a current Motorola Droid X user.
Table 1 (below) lists the 17 apps with the respective developers, version number, price, device, and measured maximum OSPL90. Thirteen of the apps appear to be marketed specifically as personal amplifiers (i.e., hearing aids). The other three, however, come under a different guise. The Microphone and Megaphone apps (Apple) are designed to be used as a public address amplifier by adding a pair of computer speakers and using the device’s built-in microphone. We substituted computer speakers with ear buds and turned the app into a hearing aid. The Super Hearing app (Android) is what appears to be a novelty for hearing conversations from a distance (like a spy device). The iStethoscope Pro app (Apple) is also a novelty and requires one to place the microphone of the iPhone/iPod on one’s bare chest, which is supposed to act like a crude version of a stethoscope bell and diaphragm chestpiece. Within the stethoscope app is a conversation mode reminiscent of a clever stethoscope trick I’ve heard used with patients with hearing loss by some healthcare providers. The clever trick is that they are placing the stethoscope eartips into their patients’ ears (hopefully after disinfecting them first, Dr. Bankaitis) and speaking directly into the chestpiece. Used in this way, the stethoscope acts like a personal amplifier for the patient.
Though ANSI S3.22 (2003) has a number of different hearing aid performance test parameters, we focus here only on the maximum OSPL90 (or Maximum Power Output [MPO]). We used the Verifit system and 2-cc coupler for all testing as well as Apple stock earbuds for consistency across devices. Depending on the app, we had to use Apple earbuds with built-in remote microphone (e.g., iPhone version) or without (iPad or iPod version). In other words, some apps are designed to use the device’s built-in microphone, 
whereas others depend on earphones or headphones with built-in remote microphones (such as for cellphone use). Referring back to Table 1, it should be clear that 5 of the 17 apps have OSPL90 values in excess of 130 dB SPL. What’s a bit scary is that there is a rule by the Food and Drug Administration (FDA; 21 C.F.R. 801, 2011) that for any medical device (i.e., hearing aid) that exceeds 132 dB SPL, special care and fitting must be taken by the dispenser to avoid pain and further damage. We knew from listening to some of these apps that they had the potential to be very loud, but we did not know how loud. We are concerned that improper use could in fact cause permanent hearing damage.
In addition to our taking OSPL90 measures, we made very general ratings for 12 of the items (average of 3 independent raters) in our Hearing Health article. Our favorites were EARs (Ear Machine), SoundAMP R (Ginger Labs), eHear (MEA Mobile), and Microphone (PocketLab) which we assigned at least 4 out of 5 stars. We based our general ratings on ease of use, little to no acoustic delays (echos), and overall sound quality. By our assessment, an overwhelming majority of amplifier apps out there on the market are just not very good. We would like to point out that the EARs app was developed by psychoacoustics researcher, Andrew Sabin, Ph.D., a graduate of Northwestern University’s Communication Sciences and Disorders program.
We are at an interesting crossroads in audiology in terms of the accessiblity of consumer-based apps that are accompanied with little to no regulation and little to no oversight by audiologists or other hearing professionals. Current amplifier apps on the market are, at best, novelty items and care should be used. We applaud several of the app developers for posting warnings with their apps, but not all do, and they probably should. Audiologists should take a cautious approach when consulting with patients about these apps. With proper instruction or use, some of these apps can be used safely and effectively in lieu of actual hearing aids with some benefit for some patients (see e.g., Eisenberg, 2012).
Samuel R. Atcherson, Ph.D. is an assistant professor in the Department of Audiology and Speech Pathology at the University of Arkansas at Little Rock in consortium with the University of Arkansas for Medical Sciences. He received his bachelors and masters degrees from the University of Georgia (1997 and 2000) and his doctorate from the University of Memphis(2006). Since 1997, Sam has given over 90 presentations to a variety of audiences on topics related to hearing assistive technology, mainstream hearing loss, classroom acoustics, age-related hearing, electrophysiology, auditory processing disorders, and health literacy. He is author of over 50 non-peer- and peer-reviewed publications, four book chapters, and two books: Auditory Electrophysiology: A Clinical Guide and Demystifying Hearing Assistance Technology: A Guide for Service Providers and Consumers. Sam is a long-time affiliate and Past President of the Association of Medical Professionals with Hearing Losses, a co-founder of the Association of Audiologists with Hearing Loss, and a proud board member of the Arkansas Hands and Voices chapter.
References
Atcherson, S.R., Spann, M.J., & Johnson, J. (2012). 12 apps to help you hear better. Hearing Health, 28(2), 20-22.
Atcherson, S.R. & Spann, M.J. (2012, April). iAudiology: integrating tablets into audiology practice. Presentation at the 2012 AudiologyNOW! convention, Boston, MA.
Eisenberg, A. (2012, May 5). For hard of hearing, clarity out of the din. New York Times: Business: Technology. URL: http://www.nytimes.com/2012/05/06/technology/audio-devices-give-new-options-to-those-hard-of-hearing.html
Hearing Devices, Professional and Patient Labeling, 21 C.F.R. § 801 (2011).
Klinger, M. & Lesner, S. (2012, March 28). Multitasking for patients 101: how to use mobile devices as hearing assistance technology. Presentation at the 2012 AudiologyNOW! convention, Boston, MA.
Quick question: do you know of a droid app that will “boost” sound (ringers, alerts, voice, etc.)? We are a school district using push to talk enabled smart phones but when you are in a cafeteria with several hundred students all talking…it is hard to hear when you get an alert/or call. I appreciate any help you can offer.
Thanks in advance,
Diane
Boerne ISD
Hi Diane:
Not sure of any apps and I will need to research that out, BUT, if you are looking for something you can place on a table so you can SEE when you have a call or an alert (as long as you put your phone on vibrator), there is a device called the LIGHT ON (blogged about it previously). Just a quick answer as I look for more information to hopefully help you out in your situation.
Thank you…I really appreciate your help. We have had situations where an administrator is in the cafeteria and he cannot be reached because he simply did not hear the alert or if he did, could not hear the caller because of the noise level in the cafeteria.
Again, thank you!
Diane
Silly question diane but do you guys utilize the vibration mode on your phones? That will at least alert you in a vibrotactile manner in noisier situations. Still looking into aps and figuring out what can work with the least amount of investment of accessories to accomplish your goals. Let me know a little more and I will get back to you as quickly as I have a solution
Diane:
check out this YouTube video from the Oaktree Products YouTube Channel that shows the Light On; this may be a potential item to consider in your sitatuion. Here is the link: http://www.youtube.com/watch?v=fmmFVn61GtE
I agree that EARs and SoundAmpR are the two best apps of the ones you tested. From my standpoint, there is one you don’t mention which beats them all: FiRe2, which is a recording app that can, by setting the input to Playthrough, be used as an assistive listening app. The advantage of FiRe2 is that there is sophisticated DSP from Izotope built in that provides several presets for compression and limiting – an absolutely essential feature for any ALD in my opinion, and virtually unavailable in the cheap “pocketalkers” I tested from assistive catalogs. For the reasons you mention, the potential for SPLs approaching 132db, I use FiRe2. Its interface, however, is more complicated than EARs or SoundAmp and would not be appropriate for a person uncomfortable with tech.
The most important point I would add is the crucial role that good earphones play when using an app like the iPhone for hearing assistance. Throw away the Apple earbuds, they’re terrible. I recommend the in-ear style like Etymotic HF 5. You can also purchase custom ear tips for Etymotic and Shure in-ears that provide even better sound. Be sure to buy earphones only and not mic-plus-earphones head sets.
Finally, the mic in the iPhone is omni. While certainly acceptable, I replace the built-in mic with a stereo directional mic called the Blue Mikey. The new Mikey, compatible with the iPhone 4s, is not yet out. However, there are alternatives, not as elegant, that you can use, such as products from Apogee or iRig. I only know the Mikey, however.
In my experience, an iPhone running SoundAmp, EARs, or FiRe2, equipped with good in-ear earphones and a directional mic makes a superb assistive listening device, far superior to just about anything else that is currently available, once you learn how to use it. In restaurants and at the theater/film, my iPhone rig delivers far clearer sound than either the house assistive systems or my hearing aids.
Richard, you bring up an oft-overlooked point: Moving the microphone closer to the person speaking will work wonders for improving the signal-to-noise ratio, markedly increasing speech discrimination.
For much more improvement, however, nothing tops FM
Dan Schwartz
Do any of these apps support sending the audio output signal using BlueTooth either to a Bluetooth T-coil loop device or directly to a hearing aid with Bluetooth?
This could be convenient to use and prevent the problem of excessive sound levels.
I will pass this question to Dr. Sam and get a response to you soon as you bring up great points. My impression is that the answer is yes, but need to check with someone more knowledgeable with these apps. Will get back to you soon! Thank you for your feedback.
He may be on vacation so I will keep trying and keep you posted.
Thanks
still no word….I will get in touch with Dr. Athcerson again and see if we can get your questions answered
I sent the question to both the SoundAmp R and the Fire developers asking whether it is possible to select the audio jack as the input and Bluetooth as the output in each iPod app. They both responded. They indicated that it isn’t really possible because the input and output selection is automatically controlled by the operating system.
That’s too bad because I wanted to set up a system like Richard Einhorn described in the NYT article, except with a more directional microphone. If I want to use the audio jack for both the microphone input and the output, I have use a splitter adapter, and it becomes a clumsy setup.
A new version of the Blue Mikey is coming out soon that is supposed be compatible with the 4th Generation iPod Touch. I will experiment with that.
I’m also trying a T-coil neck loop for the audio output. That should avoid the problem of excessive sound levels, and it may be more convenient to use.
hmmm, “really isn’t possible”….. I am sure there is a way and I am sorry that at this time i have no insight other than to think of industry peeps who we could pose this question to. Let me sit on this for a day and get back to you asap. Thanks for following up and your feedback.
Steven and A.U.: I’m investigating this very issue of Bluetooth A2DP audio not being routable, in the iOS 5 Core Audio framework, from apps that use the microphone, such as FiRe 2 and Sound Amp.
Stay tuned!
Very interesting study. I too am looking forward to reading more of it.
Dan,
Thanks for your insightful comments. I offer the following response:
We do not have a calibration problem. Our measured output levels were obtained using a calibrated Audioscan Verifit system with its standard 2-cc coupler. To be sure, we tested an actual PockeTalker using the same setup against its published specifications and came reasonably close. Given that clinical audiologists might use a hearing aid fitting system to fit Apple hearing aid apps, it just made sense to us to stick with such system. However, using a system that better simulates listening with ear buds (not strictly a 2-cc volume) might have been better. Unfortunately, the average audiologist will not have access to such equipment.
As the focus of my guest blog was on output levels in Apple and Android hearing aid apps using stock Apple ear buds, I made no attempt to describe other transducers or other parameters, and I trust my audiology colleagues to gather that Apple hearing aid apps MAY help with SNR issues either as a standalone device or coupled to hearing aids. And if they tinker with some of these apps, they will learn that some of them purportedly have built-in noise reduction features (some good, some not so good).
Probably the biggest reason I didn’t divulge much beyond output levels is because I do not want to steal the spotlight from my Au.D. student who is conducting the more comprehensive study which I stated earlier in the guest blog. After all, it was he who convinced me to buy an iPad…
Sam
Dr. Atcherson:
thank you so much for clarifying the calibration issue; your research is great and I cant’ wait to see you guys publish it. Thanks you again for your post. Very well received by my blog followers.
Overall a very good article, as indeed more and more people are using apps like this for hearing assistance. Interestingly, given your interest in ALD’s, I’m surprised that you didn’t mention how these apps can turn a mobile device into a “PockeTalker” to improve the SNR of a hearing impaired user.
Incidentally, there is a reason for the plethora of iOS vs dearth of Android audio apps: Just like on the Mac platform, Apple provides a robust audio toolbox (set of API’s) for their mobile devices, which is lacking not only on Google’s platform, but across the *nix spectrum (which also explains why you rarely see linux PC’s in audio or multimedia production).
However, from my own testing on FOAMAR Mannequin, which is Jolene OHSU-style tester, I believe that the maximum SPL levels you recorded are way too high, indicating a calibration problem: As it turns out, even when an Apple iPod earbud is driven to the displacement limits by a 1.0v P-P source with a Thevenin equivalent impedance of zero ohms (i.e. η (efficiency) = 1.0), about the most I’ve measured is about 118dB re 20µBar. This also matches up with the published findings from Etymotic Research:
My recommendation to verify your calibration is to repeat the measurements, but this time use the Ety•Kids 5 headphone (or Ety•Kids 3 headset, as needed).
Dan Schwartz, Electrical Engineer
E-mail: Dan@Snip.Net
Editor, The Hearing Blog
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ERRATA: Apparently the HTML parser swallowed the IMG SRC code for the graph from Etymotic. The graph can be found at this link towards the bottom of the page:
http://www.etymotic.com/ephp/etykids.html