Auditory SceneHearing Aid Fitting Simulator
Meet the patient in the fitting room; review the audiogram, the history and the ENT examination note. For an existing user, connect their hearing aid to the fitting software and read the data logging; for a first-time user, choose a hearing aid and an acoustic coupling to suit the loss and connect it. Make the first fit with a prescription formula and run the feedback test. Insert the probe tube and use real-ear measurement to match soft, average and loud speech to target and verify the MPO; in a child, measure the RECD. Select the programs and write the fitting to the hearing aid; if you wish, take the patient to audiometry and measure aided sound-field thresholds. When you finish, your fitting and your findings are compared with what happens in the patient’s real ear.
Works on computers and tablets · the 3D scene needs an up-to-date browser
- 15 clinical cases
- 5 follow-up cases
- 3 practice modes
- Two fitting formulas
- REM, RECD and test box
- A4 report and class code
Before you start
Four short notes to help you use the simulator smoothly.
Computer or tablet
The 3D fitting room, the patient and the fitting software have to be visible at the same time, so the simulator does not open on a phone; hold your tablet in landscape.
The first load takes a few seconds
The patient, parent, baby and room models load with the page. The 3D view needs an up-to-date browser with WebGL support.
Sound is optional
The measurement signal, the sweep and the feedback whistle are represented by short sounds; these sounds are not calibrated. What the patient and the audiologist say is shown in speech bubbles. You can mute the sound with the button in the top bar.
For educational use
This is a simulation; it does not replace clinical fitting software, a real-ear measurement system or a diagnostic tool. The hearing aids are fictional. The targets are approximate teaching values derived from the principles of published clinical fitting formulas; they are not the output of commercial or licensed fitting software.
How does it work?
The flow of a real hearing aid fitting session: prepare, choose the hearing aid and the coupling, make the first fit, then verify in the real ear and assess.
- 1
Choose the case and the mode
Pick one of the 18 clinical cases or a blind case; set the practice mode (Learning, Guided, Field), then bring the patient from the waiting room into the fitting room.
- 2
Prepare the session
Review the audiogram, the history and the ENT examination note, and check the hearing aid with a listening stethoscope. For an existing user, connect their hearing aid to the software and read the data logging. Position the patient at the real-ear measurement loudspeaker; the chair turns to face the loudspeaker, and the hearing aid, the probe tube and the neck unit are shown on the patient.
- 3
Select, fit, measure
Choose a hearing aid and an acoustic coupling to suit the degree and slope of the loss, and connect the hearing aid. Make the first fit with the intelligibility-focused or the audibility-focused formula and run the feedback test. Calibrate and insert the probe tube and confirm its placement with the REUG; match 50, 65 and 80 dB speech to target and verify the MPO with a 90 dB sweep.
- 4
Verify and assess
Talk with the patient and ask about their own voice, whistling and loud sounds; choose the programs and features and write the fitting to the hearing aid. You can take the patient to audiometry and compare unaided and aided sound-field thresholds. Submit your finding and recommendations; the fitting, the finding, the recommendations and the procedural steps are scored separately.
Cases
The cases fall into four groups: first fittings in adults, infants and children, follow-up and complaints, and difficult cases. Each patient’s individual ear acoustics (REUG, RECD, canal length) and the sound they actually hear are calculated by the engine; you do not see them, you find them by measuring.
There is also a Blind case option: the case is picked at random and its name is hidden. Blind cases run in Free mode only; you learn the expected finding when you submit your assessment.
Preparation and the 3D fitting room
The checks made before measurement show both that the hearing aid is working properly and that the measurement is reliable.
Patient and hearing aid
- Audiogram and historyTargets are calculated from air- and bone-conduction thresholds; if the UCL has been measured, it sets the limit for the MPO. For a first-time user, an acclimatisation level is chosen.
- ENT examination noteIf the note reports wax, discharge or a perforation, no probe measurement is made; wax blocks the probe tube and distorts the response.
- Listening checkThe battery, microphone and receiver are checked with a listening stethoscope; a crackly or distorted sound is confirmed in the test box.
- Test boxOSPL90, full-on gain, distortion, equivalent input noise and battery current are compared with the ANSI S3.22 tolerances.
- Loudspeaker and probe tubeThe loudspeaker is at ear level, about 1 m away and at 0 degrees. The tip of the probe tube should be within 5 mm of the eardrum.
Infants and children
The baby sits on the mother’s lap. Because a young child’s ear canal is small, the same hearing aid output produces a higher sound pressure.
- RECDThe difference between the real ear and the 2 cc coupler is measured; targets, thresholds and the MPO are converted to eardrum level using this difference.
- Simulated real-ear measurementIf the baby cannot stay still for the measurement, the hearing aid is measured in the test box and the RECD is added to the result to predict the response in the ear (S-REM).
- Audibility-focused formulaIn children the aim is for the important cues of speech to be audible at all frequencies for language development; this formula recommends more gain than the intelligibility-focused formula.
- Data loggingAt a follow-up session, hours of use, program use, volume control changes and listening environments complement the complaint with objective data.
Fitting software
The Fitting Software running on the computer on the desk. Its layout is adapted from the hearing aid fitting software and real-ear measurement systems used in the clinic; in the Turkish version, the English equivalents are shown next to the Turkish names.
| Section | In the simulator |
|---|---|
| PatientAudiogram, user, data logging | Air- and bone-conduction thresholds, UCL, pure-tone average and degree of loss. At a follow-up session, hours of use, program use, volume control and listening environments. |
| DeviceSelection, coupling, feedback | Receiver-in-canal (RIC), behind-the-ear (BTE) and in-the-ear (ITE, ITC, CIC) hearing aids, open, closed and power domes, earmoulds and shells with different vents; CROS and BiCROS. The feedback test shows the stable gain limit. |
| FittingGlobal and fine tuning, programs | Prescription formula and acclimatisation level; a gain table by frequency at 50, 65 and 80 dB input and for the MPO. Directional microphone, noise reduction, wind noise, frequency lowering, feedback manager and programs. |
| VerificationREM, test box, RECD | Probe calibration, probe depth, REUG and REOG, open-fit calibration; measurement signal (ISTS speech, pink noise, pure-tone sweep), loudspeaker angle and distance. REAR 50, 65 and 80 and a 90 dB MPO sweep in SPL-o-gram and gain views, SII and a table of deviation from target. ANSI S3.22 measurement, directional microphone and noise reduction in the test box; RECD in children. /s/ and /ʃ/ verification of frequency lowering; CROS measured from both sides. |
| CompletionLive listening and saving | The patient’s comments on sound quality, writing the fitting and the programs to the hearing aid, aided speech testing (in quiet and the Turkish Matrix Test), follow-up plan, family counselling for children, session summary. In bilateral cases the second ear can be fitted in the same session; probe tube, RECD, test box and fitting and care of the hearing aid are animated step by step. The Fitting Assistant lists the steps to try for each complaint. |
Criteria used by the simulator
The numerical criteria were chosen to agree with lecture notes and the literature. The targets are approximate teaching values derived from the principles of published clinical fitting formulas: for the intelligibility-focused formula, level-dependent compression with experience, gender, binaural and conductive corrections; for the audibility-focused formula, eardrum SPL tables, RECD conversion and adult and binaural corrections (Keidser et al., 2011; Scollie et al., 2005). In the clinic, the manufacturer’s and the measurement system’s own targets are used.
| Criterion | Value |
|---|---|
| Match to target65 dB speech | Within ±5 dB of target at 250-6000 Hz; the response slope in each octave within ±5 dB/octave of the target slope (BSA 2018). With an open coupling, frequencies below 1 kHz, and in a dead region the affected frequencies, are excluded from the assessment. |
| MPO90 dB SPL sweep | The real-ear saturation response should stay below the discomfort level (UCL) at every frequency. |
| Probe tubePlacement | Tip within 5 mm of the eardrum; in adults about 28-30 mm from the intertragal notch. With shallow placement a quarter-wave notch appears in the REUG around 5-6 kHz. |
| REUGOpen-ear gain | In adults a resonance peak of about 15-18 dB around 2.5-3 kHz, returning to near zero towards 6 kHz. |
| RECDReal-ear-to-coupler difference | Decreases with age; in infants it approaches 20 dB at high frequencies. The measured RECD is applied to the target, the threshold and the MPO. |
| Test boxANSI S3.22 | OSPL90 ±3 dB, full-on gain ±5 dB; total harmonic distortion and equivalent input noise no more than 3 units above the manufacturer’s value, battery current no more than 20% above it. |
| Measurement signalISTS and loudspeaker | The speech-like ISTS signal is used; with pink noise, noise reduction turns the gain down, and with a pure-tone sweep, compression and the feedback manager behave differently. The loudspeaker is at 0 or 45 degrees, about 1 m away; measurement at 90 degrees is not reliable. |
| SIISpeech intelligibility index | Shows how much of speech is audible on a scale of 0-100; a simplified calculation with ANSI S3.5 band-importance weights. |
Modes and score
You can practise the same case with different levels of support. Your score looks not only at the fitting but also at how you ran the session.
Practice mode
- LearningThe step-by-step guide is open: preparation, data logging, test box, hearing aid and coupling, first fit, feedback, RECD, probe calibration, real-ear measurement, MPO, programs, live listening and saving.
- GuidedYou do the steps in any order you like; short explanations remain in the preparation steps.
- FieldThere is no guidance; you see only the software’s own warnings. Blind cases run in this mode.
How is the score calculated?
- 1Fitting (40%)Match to target in the patient’s real ear, the MPO staying below the discomfort level, feedback, and whether the hearing aid and coupling suit the loss.
- 2Finding and recommendations (40%)Your main finding and recommendations such as follow-up, counselling and referral, compared with the expected ones.
- 3Technique (20%)Preparation, test box, feedback test, RECD, probe calibration and REUG, measurement at three levels, MPO, programs, live listening and writing to the hearing aid.
Results are kept only in your own browser. You can download the A4 report and send your result and report to your instructor with the class code.
Frequently asked questions
The fitting software’s first-fit suggestion is calculated for an average ear. Because the size and resonance of the ear canal and the leakage of the coupling vary from person to person, the same fitting produces different sound pressures in different ears. A thin probe tube placed near the eardrum measures the sound the hearing aid produces in that ear, and this is matched to target.
Research shows that the first-fit suggestion falls below target at high frequencies in most patients and that fittings verified with real-ear measurement give better outcomes.
Both are fitting formulas that calculate target gain from the audiogram. The intelligibility-focused formula aims to make speech as intelligible as possible while keeping overall loudness comfortable; in the simulator it is expected in adult cases. The audibility-focused formula aims to make the important cues of speech as audible as possible; it is expected in child and infant cases and usually prescribes more gain.
It is the difference in sound pressure between the real ear and a 2 cc coupler. Because a young child’s canal volume is small, the same hearing aid output produces a higher sound pressure in the ear; using a measured RECD instead of an age norm ensures that both the gain and the MPO are set correctly.
With an open coupling, the sound the hearing aid produces in the canal leaks out of the ear and reaches the reference microphone. The measurement system mistakes it for loudspeaker sound and turns the loudspeaker down, so the response looks lower than it really is at low and mid frequencies. Calibration is done with the hearing aid muted and is kept fixed throughout the measurement.
No. The simulator runs entirely in your browser; no recording is sent to a server. If you choose to enter your name for the report and the class code, it is stored only in your own browser.
The 3D room, the patient and the fitting software have to be visible at the same time. At phone width this layout becomes unusable, so small screens are blocked on purpose. A tablet works in landscape.
No. What is being fitted here is a virtual patient’s hearing aid, and you are the clinician. If you have a question about your own hearing or hearing aid, please contact your audiologist.
Kaynaklar
The simulator’s criteria, target model and measurement protocols are based on the sources below.
- Dillon, H. (2012). Hearing Aids (2nd ed.). Boomerang Press; Thieme.
- Keidser, G., Dillon, H., Flax, M., Ching, T., & Brewer, S. (2011). The NAL-NL2 prescription procedure. Audiology Research, 1(1), e24.
- Byrne, D., & Dillon, H. (1986). The National Acoustic Laboratories' (NAL) new procedure for selecting the gain and frequency response of a hearing aid. Ear and Hearing, 7(4), 257-265.
- Dillon, H., & Storey, L. (1998). The National Acoustic Laboratories' procedure for selecting the saturation sound pressure level of hearing aids: theoretical derivation. Ear and Hearing, 19(4), 255-266.
- Scollie, S., Seewald, R., Cornelisse, L., et al. (2005). The Desired Sensation Level multistage input/output algorithm. Trends in Amplification, 9(4), 159-197.
- Bagatto, M., Moodie, S., Scollie, S., et al. (2005). Clinical protocols for hearing instrument fitting in the Desired Sensation Level method. Trends in Amplification, 9(4), 199-226.
- Mueller, H. G., Ricketts, T. A., & Bentler, R. (2017). Speech Mapping and Probe Microphone Measurements. Plural Publishing.
- British Society of Audiology (2018). Guidance on the verification of hearing devices using probe microphone measurements.
- Holube, I., Fredelake, S., Vlaming, M., & Kollmeier, B. (2010). Development and analysis of an International Speech Test Signal (ISTS). International Journal of Audiology, 49(12), 891-903.
- Moore, B. C. J. (2004). Dead regions in the cochlea: conceptual foundations, diagnosis, and clinical applications. Ear and Hearing, 25(2), 98-116.
- ANSI/ASA S3.22-2014. Specification of Hearing Aid Characteristics. ANSI S3.5-1997. Methods for Calculation of the Speech Intelligibility Index.
- Glista, D., & Scollie, S. (2009). Modified verification approaches for frequency lowering devices. AudiologyOnline.
- American Academy of Audiology (2013). Clinical practice guidelines: Pediatric amplification.
- Zokoll, M. A., Fidan, D., Türkyılmaz, D., et al. (2015). Development and evaluation of the Turkish matrix sentence test. International Journal of Audiology, 54(sup2), 51-61.
If you are ready, the patient is waiting in the fitting room
If you spot an error, if a criterion does not work correctly or if there is a case you would like us to add, write to us: info@isitmeatolyesi.com. The simulator is an open-ended educational project; it grows with your feedback.