Behind the Mimi Hearing Test App -Mimi’s hearing testing technology explained by Jane Grabowski

Ever wondered how well you hear? The Mimi Hearing Test app is a free digital hearing screening tool that is easy to complete and the perfect application if you are curious about your hearing health. You will be guided through a hearing test and can perform it in the comfort of your own home. It takes just a few minutes, and can be done directly from your smartphone. After completing the test you will receive individualized results about your hearing.

We asked Mimi’s Clinical Research Operations Manager Jane Grabowski for more information about Mimi testing technology, how to use the app, and the results it provides.

Can you explain how Mimi developed its hearing test and ensure its accuracy? 

We have developed two tests, a pure-tone threshold and a masked threshold test, the premise of both of which are based on published literature and the scientific principles which underlie hearing testing in general. Everything we do at Mimi is done in a team approach, with hearing test technology and sound processing development driven by our research team. The team is a group of highly educated and talented individuals with PhDs or Masters spanning from Auditory Psychoacoustics, Audio Engineering, Data Science and Translational Neuroscience.

Can you tell us more about the Pure-Tone Threshold (PTT) test?

The pure-tone threshold (PTT) test is available on our iOS Hearing Test App. This test is modeled after the Békésy tracking procedure and lends itself particularly well for app-based mobile hearing tests, in part because it was designed as an automated test procedure for determining air-conduction thresholds in the first place. 

Accuracy was determined through diagnostic accuracy studies (DATs) run in our lab or in conjunction with various biotech and academic partners. DATs compare the test you are interested in to a gold standard under identical test conditions. We’ve also run studies to establish reliability. Efforts are currently in place to make accuracy, reliability, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) data more transparent through collaborations with various university medical centers with the intent of subsequently publishing the results in peer-reviewed journals. Some studies have already been published, such as this validation study by Yesantharao et al. (2022).

Can you tell us more about the Masked Threshold (MT) test?

Mimi’s Masked Threshold (MT) test is an advanced device-agnostic hearing test developed for unknown testing hardware. It measures the quietest level of a pure-tone that a user can perceive in the presence of a masker (i.e. noise) at a specific frequency. This correlates with the ability to make sense of complex soundscapes. This ability is called spectral tuning, with broad tuning being an indicator of hearing impairment. The MT test displays a hearing grade, but does not provide any additional frequency-specific information like the PTT test. This test is available for the Android operating system and is also available in the Mimi Hearing Test app for iOS. 

What is your advice on how to take a hearing test with the Mimi Hearing Test app? 

Our design and usability product teams have put in extensive effort to ensure an intuitive testing experience. For the PTT test, I would recommend working through the app test flow in a quiet, distraction free zone with one of the recommended headphones for which we have determined correction factors in our lab. Testing is interrupted when a period of “inactivity” is detected. This may be because the end user is actually inactive or more typically, because the user has thresholds or hearing outside of the testable range at one or more test frequencies. There is an option to continue and complete testing or to skip that ear. An important detail is that the app is intended for individuals with thresholds in the normal to moderately-severe range. This is in great part due to hardware limitations of the testing equipment, in this case being consumer tech headphones and smartphones. 

How should users proceed after receiving their test results? 

After completing the PTT test, an audiogram with the right and left ear is displayed along with a pure-tone average (PTA-4) calculated as the average of the thresholds at 500, 1000, 2000, and 4000 Hz following the WHO guidelines; we call this “Your average hearing loss”. The Johns Hopkins Cochlear Center for Hearing and Public Health has launched a fantastic campaign, renaming this as your ‘Hearing Number’.

I would encourage users to review the Hopkins Hearing Number campaign after they receive their test results to get a better sense of what their test results might mean for them and what solutions exist to help address hearing loss. Furthermore, I would recommend follow-up with an audiologist or physician if any concerns about your hearing exist, independent of the test result. In the event of sudden hearing loss, they should immediately follow up with a physician, as this constitutes a medical emergency.

I also want to highlight that the Mimi test does not under any circumstance replace a full diagnostic workup with an audiologist. While the pure-tone threshold audiogram is a cornerstone of understanding your hearing sensitivity, it only assesses a small portion of what enables someone to hear and more importantly, make sense of what has been heard. 

How accurate are Mimi’s available hearing tests? 

Under ideal test conditions and when used as intended by the considered population, the tests are very accurate, as has been confirmed in scientific publications such as Virtual audiometric testing using smartphone mobile applications to detect hearing loss.

Where can I find the free hearing tests? 

The PTT test is calibrated for iOS (Apple) devices and requires iOS 13.0 or later. To test your hearing using the Mimi pure-tone threshold test, download the Mimi Hearing Test App from the App Store. The PTT test provides the greatest level of detail/frequency-specific information about your hearing, but requires that you use certain types of headphones for most accurate results. 

For Android users, Mimi offers the masked threshold test which broadly categorizes your hearing into varying categories, from excellent to impaired. This can be downloaded from the Google Play Store.

 

About Jane

Jane Grabowski is Clinical Research Operations Manager at Mimi Hearing Technologies. Jane earned her Doctor of Audiology at Towson University and is working towards a Ph. D. at Charité Universitätsmedizin – Berlin. Jane has gathered clinical and research experience in audiology at Johns Hopkins Bayview Medical Center, the National Institute on Deafness and Other Communication Disorders (NIDCD)and the National Center for Rehabilitative Auditory Research, the Department of Veterans Affairs, among other institutions. Before joining the Mimi team in 2020, the clinician-scientist was the Audiology Clinic Director at California State University in Sacramento.