Auditory SceneABR Simulator
Read the ENT request; prepare the adult patient, the baby in a parent's arms or the child under sedation. Clean the skin with gel and place the electrodes according to the colour code, measure the impedance and fit the insert earphones. In the EP recording software, set the stimulus and filters and record from both ears; monitor the EEG and the rejected sweeps. Mark waves I, III and V and search for the threshold. When you finish, compare your findings, interpretation and recommendation with the expected answers.
Works on computers and tablets · the 3D scene needs an up-to-date browser
- 15 clinical cases
- 7 baby and child cases
- 3 practice modes
- Electrode montage and impedance
- Threshold estimation
- A4 report and class code
Before you start
Four short notes to help you use the simulator smoothly.
Computer or tablet
The 3D room, the patient and the EP recording software must be visible at the same time. For this reason, it does not open on a phone screen; hold your tablet in landscape.
The first load takes a few seconds
The patient, parent and room models load with the page. 3D rendering needs an up-to-date browser that supports WebGL.
Sound is optional
Click and tone burst stimuli play at a low level and are not calibrated; the patient's, parent's and audiologist's speech is shown in written speech bubbles. You can turn the sound off with the button in the top bar.
For educational use
This is a simulation; it does not replace a clinical diagnostic tool or a calibrated evoked potential system. The software screen does not represent any particular device; the waveforms are generated from a virtual patient.
How does it work?
The flow of a real ABR session: read the request, prepare the patient and the electrodes, record from both ears, mark and interpret the waves.
- 1
Choose the case, the mode and the speed
Choose one of the 15 clinical cases or the blind case. Set the patient's cooperation, the practice mode (Learning, Guided, Field) and the recording speed (accelerated or real time), then go to the ABR and OAE room.
- 2
Prepare the patient
Read the ENT request; explain the test to the patient or inform the parent. Clean the skin with gel, place the electrodes, measure the impedance and fit the insert earphones. With a sedated child, first check the monitor, the team and the airway.
- 3
Record
Select the protocol in the EP recording software; set the stimulus, filters and rejection level. While recording, monitor the EEG, rejected sweeps, Fmp and residual noise. Confirm the response with a replication and lower the level towards threshold.
- 4
Mark and interpret
Edit tab: mark waves I, III and V; the latency table and the latency-intensity graph fill in. For each ear, choose the waves, the latency pattern, the threshold and the interpretation. Your answers are compared item by item with the expected answers and can be downloaded as an A4 report.
Cases
The cases fall into four groups: neuro-otological assessment in adults, threshold estimation in adults, infants and sedated children. Each time you open a case, a new patient is generated: the affected side, the thresholds and the impedances change, so you will not see the same waves when you repeat a case.
There is also a Blind case is available as an option: the case is chosen at random and the diagnosis is hidden. The blind case runs only in Free mode; you learn the diagnosis when you submit your assessment. Using the Patient file bridge, you can take the same patient to the audiometry, acoustic immittance or OAE simulator.
Preparation and the 3D scene
The ABR is a response of about a tenth of a microvolt; the quality of the recording is largely decided while the electrodes are being attached and the patient is lying down.
Prepare the patient
- ENT requestNeuro-otological assessment or threshold estimation? The protocol, levels and stimulus type are chosen according to the request.
- Skin preparationSqueeze the gel onto the gauze, then pick up the gauze and rub back and forth over the marked sites. Too little rubbing leaves the impedance high; too much irritates the skin.
- Electrode montageWhite active electrode on the vertex (on the high forehead in babies), black ground on the low forehead, red on the right mastoid and blue on the left. An electrode in the wrong place inverts the waveform or records the response of the opposite ear.
- ImpedanceEach electrode below 5 kΩ, and the difference between electrodes no more than 2 kΩ. High or unbalanced impedance increases mains interference.
- Insert earphonesRed in the right ear, blue in the left; the foam tip should be the right size for the canal. The tube delay separates the stimulus artefact from the response in time.
- Relaxation and interferenceThe EEG gets smaller when the patient's eyes are closed, the jaw is relaxed or the patient is asleep. Swallowing, jaw clenching and head movement cause sweeps to be rejected; a phone in the pocket also causes interference.
Infant and sedated child
A baby is tested in natural sleep in the parent's arms. A young child who cannot be tested in natural sleep lies on the couch under sedation given by a physician.
- SleepA baby who has just been fed falls asleep easily in a dim room. Sucking, wriggling and crying make the EEG larger; pausing the recording and waiting for the baby to settle is often quicker.
- Small tips and high foreheadIn babies, the active electrode is placed on the high forehead because of the anterior fontanelle; a small foam tip is used because the ear canal is narrow.
- Sedation safetyBefore recording, check the pulse oximeter, the sedation team and the emergency equipment, and the child's position and airway. If the child snores or SpO2 drops, adjust the head position; if that does not help, call the team.
- Limited timeBoth sleep and sedation are limited. First record a high-level click and search for the threshold in both ears, then, if time allows, make frequency-specific recordings.
EP recording software
Evoked potential software running on the computer on the ABR cart: Record and Edit tabs, system settings and the impedance window.
| Section | In the simulator |
|---|---|
| ProtocolsPresets | Neuro-otological click (80 dB nHL, 21.1/s, 100-3000 Hz, 2000 sweeps) and quick click; click, tone burst and chirp for threshold (39.1/s, 33-1500 Hz); ANSD and bone-conduction protocols. |
| StimulusType, level, polarity | Click, tone burst (500-4000 Hz) and chirp; level in dB nHL; rarefaction, condensation or alternating; repetition rate; insert earphones or bone vibrator; contralateral masking; tube pinch check. |
| RecordLive monitoring | Raw EEG and rejection level, accepted and rejected sweeps, A and B buffers, reproducibility, Fmp and residual noise. Traces are shown in two columns, colour-coded by ear. |
| System settingsFilters and averaging | High-pass and low-pass filters and their slopes, notch filter, analysis window, rejection limit, number of sweeps, Bayesian weighted averaging, tube delay correction, stopping criterion. |
| EditMarking and table | Marks for I, III and V; absolute and interpeak latencies (values outside the norms in red), interaural wave V difference, a plot of wave V latency against intensity with the norm band. |
| InterferenceRealistic noise | Muscle activity, swallowing and movement; 50 Hz mains interference that depends on impedance; mobile phone interference. Finding the source and removing it is your job. |
| Recording timeAccelerated or real time | In accelerated recording, sweeps are collected 5 times faster; all the stages stay the same. The duration display and the sedation clock show the clinical time that would really pass. |
Criteria used by the simulator
The normative latencies are based on a study of young adults with normal hearing in TĂĽrkiye. Institutional protocols and device defaults may differ slightly from these values.
| Criterion | Value |
|---|---|
| Absolute latenciesClick, 80 dB nHL | I 1.37 ms, III 3.51 ms, V 5.28 ms (Belet et al. 2022). The software shows values more than 2.5 standard deviations above the norm mean in red. |
| Interpeak intervalsClick, 80 dB nHL | I-III 2,14 ms, III-V 1,77 ms, I-V 3,91 ms. |
| Interaural wave V differenceRetrocochlear involvement | An interaural difference in wave V latency of more than 0.4 ms suggests eighth nerve involvement. |
| V/I amplitude ratioRetrocochlear involvement | In normal hearing, wave V is larger than wave I (ratio above 1); in adults a ratio below 0.5 is considered pathological. |
| ImpedanceElectrode preparation | Each electrode below 5 kΩ, with a difference of no more than 2 kΩ between electrodes. |
| Response reliabilityFmp and residual noise | Fmp above 3.1 or residual noise below 40 nV; a replication recorded with the same parameters should overlay the first trace. |
| ABR thresholdThreshold estimation | The lowest level at which wave V is seen reproducibly. The click threshold reflects roughly the 2-4 kHz region and is usually 10-20 dB above the behavioural threshold. |
| Latency patternsSite of lesion | Conductive: all waves are delayed, interpeak intervals are normal. Cochlear: close to normal at high levels, with a steep latency-intensity function near threshold. Retrocochlear: I-V is prolonged. Brainstem: III-V is prolonged and V is reduced. |
| Infants and childrenMaturation | In newborns, latencies and the I-V interval are long (at term, with a 70 dB nHL click, V is about 6.8 ms and I-V 5.0 ms); they shorten with age. The means and standard deviations for the age groups are taken from the doctoral thesis of Külekçi (1995). |
| ANSDCochlear microphonic | The cochlear microphonic inverts with stimulus polarity while the neural waves do not; it disappears when the sound tube is clamped. Alternating polarity cancels the CM. |
Modes, score and achievements
You can work through the same case with different levels of support and at two different speeds. Your score looks not only at your interpretation but also at how you obtained the recording.
Practice mode and recording time
- LearningYou follow the clinical order step by step: request, patient, skin, electrodes, impedance, earphones, recording and replication in both ears, threshold, marking, assessment. Every step has a "Why?" explanation.
- GuidedYou do the steps in any order you like; hints on noise, montage and protocol appear as they become relevant.
- FieldThere are no hints; you only see warnings for clear errors. The blind case runs in this mode.
- Accelerated or real timeWith accelerated recording a case takes about 15-25 minutes. With the real-time option, recordings take as long as in the clinic: 30-60 minutes for an adult including preparation, and 45-90 minutes for an infant or a sedated child.
How is the score calculated?
- 1Interpretation (70%)For each ear: the waves at a high level, the latency pattern, the click threshold in cases where a threshold is requested, and the interpretation of the ear; the likely clinical picture and recommendations.
- 2Procedure (30%)ENT note, instructions or information, skin cleaning, montage, impedance, insert earphones, recording quality and replication, a protocol that suits the request. For a sedated child, also the safety check, the response to an airway event and the use of the sedation time.
- 3Stars and experienceThe total score is converted to 1-3 stars; you level up with experience points and earn achievements such as First Case, Flawless Interpretation, Clean Montage, Sleep Guardian and Clean Technique.
Your progress is kept only in your own browser; no data is sent to a server. Instructors can view a student’s result and report with the class code.
Frequently asked questions
It is a small electrical response generated by the auditory nerve and the auditory pathway in the brainstem in the first 10-15 milliseconds after a brief sound stimulus. It is recorded with electrodes attached to the scalp and separated from EEG and muscle noise by averaging thousands of sweeps.
The waves are named with Roman numerals. Wave I arises from the part of the auditory nerve close to the cochlea, wave V from the upper brainstem. Because it does not require the patient to respond, it is used for threshold estimation in infants and in patients who cannot be tested behaviourally.
In a neuro-otological assessment, the latencies of waves I, III and V and the intervals between them are measured with a click at a high level (70-80 dB nHL); the integrity of the auditory nerve and the brainstem pathway is examined.
In threshold estimation the level is lowered step by step and the lowest level at which wave V is seen is sought. Tone bursts are used for frequency-specific information. Filter, rate and window settings also differ between these two purposes.
The outermost dead layer of the skin and skin oil resist electrical current. Rubbing with abrasive gel lowers the impedance. Low, balanced impedance lets the differential amplifier suppress mains interference; otherwise the recording fills with 50 Hz interference.
No. The ABR threshold is usually 10-20 dB above the behavioural threshold, and the click threshold reflects roughly the 2-4 kHz region. Frequency-specific thresholds (tone burst) are needed for hearing aid fitting; the ABR threshold is interpreted together with behavioural tests.
The ABR is hundreds of times smaller than EEG and muscle activity. When the patient’s eyes are closed and the jaw is relaxed, or the patient is asleep, the noise falls and the response becomes visible with far fewer sweeps. Infants are tested in natural sleep; some children who cannot be tested in natural sleep are sedated on the physician’s decision.
All the stages are the same in both options. In accelerated recording, sweeps are collected 5 times faster, so a case fits into a class session. In real-time recording, each trace takes as long as in the clinic; this is a good way to experience how long an ABR session really takes. In both options the assessment screen shows how long the test would take in the clinic.
No. The simulator runs entirely in your browser; no recording is sent to a server. Your level, best scores and achievements are kept only in your own browser’s local storage.
The 3D room, the patient and the EP recording 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. The person being tested here is a virtual patient, and you are the clinician. If you have concerns about your hearing or your ears, contact an audiology clinic.
Kaynaklar
The simulator’s normative values, wave model and answer key are based on the sources below.
- Külekçi (Özbayır), S. (1995). Bebek ve çocuklarda ABR normatif veri [ABR normative data in infants and children] [Doctoral thesis].
- Belet, U., Akşit, A. M., & Kösemihal, E. (2022). İşitsel beyinsapı cevaplarında normal işiten bireylerde LS Chirp ve klik uyaranın karşılaştırılması [Comparison of LS Chirp and click stimuli in auditory brainstem responses in individuals with normal hearing]. Turkish Journal of Audiology and Hearing Research, 5(1), 1-5.
- Türk, Ç., Çeliktepe, D., & Konukseven, Ö. (2020). Normal işiten bireylerde kemik iletim ABR testi normalizasyonu [Normalisation of the bone-conduction ABR test in individuals with normal hearing]. 10. Ulusal Odyoloji ve Konuşma Bozuklukları Kongresi [10th National Congress of Audiology and Speech Disorders] (conference abstract).
- Yiğit, Ö., Özbal Batuk, M., Çiçek Çınar, B., Yıldırım, M., Yaralı, M., & Sennaroğlu, G. (2020). Auditory brainstem response measurements in newborns: which electrode placement is better? Turkish Archives of Otorhinolaryngology, 58(2), 112-117.
- Jewett, D. L., & Williston, J. S. (1971). Auditory-evoked far fields averaged from the scalp of humans. Brain.
- Elberling, C., & Don, M. (1984). Quality estimation of averaged auditory brainstem responses. Scandinavian Audiology.
- Starr, A., Picton, T. W., Sininger, Y., Hood, L. J., & Berlin, C. I. (1996). Auditory neuropathy. Brain.
- Joint Committee on Infant Hearing (2019). Year 2019 position statement: principles and guidelines for early hearing detection and intervention programs. Journal of Early Hearing Detection and Intervention.
- Coté, C. J., Wilson, S., American Academy of Pediatrics, & American Academy of Pediatric Dentistry (2019). Guidelines for monitoring and management of pediatric patients before, during, and after sedation for diagnostic and therapeutic procedures. Pediatrics.
- British Society of Audiology. Recommended procedure: auditory brainstem response (ABR) testing in babies.
- Hall, J. W. New Handbook of Auditory Evoked Responses. Pearson.
- Hood, L. J. Clinical Applications of the Auditory Brainstem Response. Singular.
If you are ready, let’s move to the couch
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.