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All of our learning opportunities can be categorized into one of three levels of learning: Introductory, Intermediate, and Advanced. One of the three icons displayed below will be displayed on each resource to quickly identify the straightforwardness to complexity of the content. ADVANCE provides a variety of content designed to suit all audiologists' needs.




Middle ear testing has been a standard component in audiometric evaluations for many years. It is performed regularly to objectively document the compliance of the middle ear system, monitor chronic middle ear fluid, evaluate Eustachian tube function, and used in combination with the audiogram to develop a complete picture of a patient’s hearing. In the majority of cases, using the total admittance (Y) obtained with the 226 Hz probe tone provides sufficient information for basic diagnosis. This is the fastest way to “confirm” a normal middle ear system. However, when a more critical look at the middle ear is required, higher frequency probe tones and individual admittance components can provide detailed information.

What are the components of admittance?
Middle ear testing has been described as evaluating the impedance of the ear. Impedance refers to the opposition of the flow of energy. In other words, if energy (sound) is introduced to a system (ear), how much of the energy is blocked or impeded. Impedance is not a practical measurement for an office setting, so the commercial impedance bridges are actually measuring admittance which is the inverse of impedance. Admittance is measuring the ease at which energy (sound) flows through the system (ear). Admittance (Y) is a measurement taken at the plane of the tympanic membrane and is made up of two components: susceptance (B) and conductance (G).

Susceptance (B) is referred to as the “stiffness” of the middle ear system and refers to the relationship between the springy parts and the mass of the middle ear. In other words, this is the way the ligaments, tendons, and muscles work with the bones in the middle ear to transmit sound. Typical middle ear testing at 226 Hz probe tone provides very predictable and reliable results using the total admittance (Y). There is no need to separate the individual components because the total admittance (Y) is equal to the susceptance (B) at that probe tone. Research has shown that when using the 226 Hz probe tone, the springy portion of the susceptance is transmitting the sound through the system.

The ear is a machine with working parts, and therefore there will be a natural amount of energy lost. Conductance (G) refers to the loss of energy due to friction in the system.


What is the difference between probe tones?
As the frequency of a stimulus is increased and gets closer to the resonance frequency of the ear, there is a natural evolution of the morphology of the tympanogram. These changes in the tympanogram are expected and follow a general rule. Sound is being transmitted be the springy portion of the ear with a low frequency probe tone (226 Hz) and the resulting tympanogram will by the typical type A. As you move to a mid-frequency probe tone (such as 678 or 1000 Hz), the mass portion of susceptance is more involved with sound transmission and the resulting tympanogram will develop multiple peaks or notches. At the resonance frequency of the ear, the tympanogram will have multiple peaks and is described as an inverted W. When using a high frequency probe tone that is above resonance frequency, the tympanogram will continue to evolve into a V shape (opposite of 226 Hz) because the mass portion of susceptance is transmitting the sound.

When is it appropriate to use different probe tones?
For basic diagnosis of middle ear function, the 226 Hz probe tone is completely appropriate. When a more detailed look at the individual components of the middle ear is required, 678 Hz should be the “go to” probe tone frequency. Tympanometry with 678 Hz is typically performed when the audiologic results don’t add up. Examples of when to use 678 Hz probe tone tympanometry are:

1. Presence of an air-bone gap with a normal 226 Hz tympanogram.
2. Abnormally steep gradient (suspected disarticulation).
3. Patient complaints are consistent with middle ear pathology that is not detected with a basic tympanogram.

The 1000 Hz probe tone is utilized for the basic evaluation of the infant ear because the middle ear structure in patients under 6 months of age is different than that of patients over 6 months of age. The infant ear is mass dominated and has a lower resonance frequency which can create complex morphology and notching when using a low frequency probe tone. The 1000 Hz probe tone is far away from the resonance frequency of the infant ear and will result in more predictable morphology that is consistent with common middle ear pathologies for the infant patient population.

Interpreting results when using different probe tones
When using probe tones other than 226 Hz, susceptance and conductance should be viewed simultaneously. Baseline, or compensated, is not used. The shape of the tympanogram is classified by the number of peaks, or extremum, that are present in B and G. There are four normal classification types: 1B1G, 3B1G, 3B3G, and 5B3G. Examples of normal B/G tympanograms are shown below. Tympanograms are considered abnormal if there are too many peaks or if the peaks are too wide. See examples below of abnormal B/G tympanograms. These results often help distinguish between ossicular discontinuities and other disorders – even when no abnormality is present on the 226 Hz tympanogram.


For 1000 Hz probe tones, refer to normative data and look for any discernable peak. 




How can I load recorded speech on my GSI Audiometer? The AudioStar Pro and Pello include over 100 widely used recorded wordlists. Below, you will find the list of the included CDs on the AudioStar Pro and Pello audiometers:

Basic Auditory Evaluation - Adult
Spondee - A and B
NU6 list 1a - 4a
W-22 list 1a - 4a

Basic Auditory Evaluation - Child
Spondee Child
PBK lists 1a - 3a

Spanish Auditory Speech List
2 lists for SRT (Tri syllable)
4 lists for WRS (Two syllable)

VA CDs 1, 2, and 4

The AudioStar Pro includes the following Special Tests* on every instrument and the Pello includes the following Special Tests with the Speech Plus License:
AZ Bio Sentences
AZ Bio Sentences Pediatric
*Additionally, the TEN Test is integrated into every AudioStar Pro.

In order to add additional CDs to your audiometer, GSI must extract the tracks from the CD and convert them to XML .WAV files. The original CD that you wish to be extracted as well as the score sheet (or script) with the lists of words on each track will need to be mailed to GSI along with the letter of ownership document. The letter of ownership states that the CD is your media and you are allowing GSI to change the format of it. Additionally, the document requests information about the audiometer to be loaded with the new .WAV files to ensure the proper format is delivered. This process takes 4 - 6 weeks to complete so if it is a CD that you use frequently, it is recommended that you make a copy to keep in your office for use during the time it is processing at GSI. When the extraction process is complete, GSI will send a USB drive with the new files for you to load on your instrument.




Yes. The Corti can easily test patients with PE tubes. To do so, the probe check needs to be disabled. The Corti runs a probe check that begins automatically after testing is initiated. The probe check display shows a cone, larger at the left and tapering toward the right, representing the ear canal volume from very large (blue area) to very small (orange area). The vertical white bar indicates the measured ear canal volume and probe fit stability.

If the measured ear canal volume is in the normal range for testing and the vertical bar is stable in the gray portion of the cone, it will turn green, the device will calibrate, and testing will be initialized:



If the ear canal volume is too large for the test to begin, the probe is not in the ear, or there is a large leak, the ear seal indicator will move to the left in the blue part of the cone.



In patients with patent PE tubes, the probe check will not pass, no matter how well the probe is positioned in the ear canal. To complete testing, the probe check needs to be bypassed. This is accomplished by first inserting the probe with appropriate ear tip into the ear canal and obtaining a proper seal. To disable AutoStart at the main menu, select the ear to be tested by holding down the RIGHT or LEFT arrow key for three seconds until the green “ready” light turns off. Once the key is released, the Corti will calibrate and test as before. The appropriate in-the-ear stimulus intensity levels are applied to ears with PE tubes.

How Reliable is Automated Audiometry?



The results of AMTAS are data driven and evidence based. They are then used to calculate the overall accuracy and a number of other important markers that will basically give the audiologist an image of how the patient was acting during the test. It is important that you are familiar with these.

The Quality Indicators that are most impressive to audiologists and ENTs are as follows: Predicted Average Absolute Difference, Time Per Trial, False Alarm Rate, and QC Fail.

Predicted Accuracy - Overall Quality - Good, Fair, Poor – based on the quality indicators.
Predicted Average Absolute Difference – Difference between automated and manual thresholds based on a study where five expert audiologists tested patients manually and compared the results to AMTAS evaluations – based on research.
Masker Alerts - These indicate thresholds where masking may have been too high or low. 
Time Per Trial - Measures the average time from stimulus to patient response.
False Alarm Rate – The number of times patient responded with no stimulus presented is divided by number of trials when no stimulus was presented. When there is a false alarm, AMTAS displays a message to alert the patient that he responded yes when there was not a tone presented. 
Average Test-Retest Difference – Displays the average difference between 1 KHz test and retest in the right and left ears.
Quality Check Fail Rate – When threshold is established, AMTAS presents a stimulus that is 5 dB above threshold. The patient should hear this tone. QC fail indicated the number of times patient did not respond to stimulus above threshold divided by the number of measured thresholds. If this is high, it can indicate malingering or that the patient is not a good candidate for AMTAS.
Number of Air/Bone Gap > 35 dB – This is the number of air/bone gaps that exceed 35 dB.
Number of Air/Bone Gap < -10 dB – This is the number of air/bone gaps that are less than 10 db

If the data and research is not convincing enough, patient care situations can help:

- If an ENT cannot find an audiologist but he has a patient that requires audiometric testing, he must end the appointment, send the patient across town to the audiologist he refers to, and then wait for the patient to come back. This adds a level of complexity that is inconvenient. The patient must then make an appointment, go to the appointment (pay the copay), and then make and go to a follow up appointment (copay again) with the ENT. If that office had AMTAS, they would still likely refer to audiology, but they would be able to complete the patient’s appointment more efficiently. 

- If an audiologist is supporting an ENT clinic and has several patients who need audiometry at the same time, the patients will have to wait until the audiologist completes testing with the previous patients before they can be seen. This can add up to a long time in a waiting room for a hearing test. If that audiologist had AMTAS, one patient could be working through a basic air/bone/speech while other patients were undergoing middle ear testing, OAEs, or counseling.

- If a busy clinic has AMTAS, a walk-in patient with sudden hearing loss can be tested immediately and worked into the schedule for immediate treatment.

- A satellite office where an audiologist is not available every day can see more patients and be more effective by using AMTAS.

The biggest drawback to AMTAS (from an audiologist or ENT perspective) is the billing. Currently, there is not a billing code in place for this evaluation. GSI believes that in the next couple of years that will change. In the meantime, the small amount of money that is reimbursed for the air/bone/speech is made up for by the time and other testing that can be performed by the audiologist.

GSI AMTAS is a powerful automated audiometry tool that can benefit a clinic in many ways. For more information, visit to learn what AMTAS can do for you!

What Are the Differences Between a 2 Channel and 1.5 Channel Audiometer?



There a few major differences between a two-channel and a one-and-a-half-channel audiometer.  Most of us have experience using a two-channel audiometer like the AudioStar Pro™ (or the GSI 61™) with mirror controls for channel one and channel two.  With a two-channel audiometer, you are able to use channel one to conduct speech audiometry, while you have tone stimulus routed through channel two.  It is also possible to route stimuli from both channels into the same ear for seamless pediatric testing. Both channels have the ability to present and route stimuli to any ear and transducer that is available. Two-channel audiometers are considered type one audiometers and are the industry standard for clinical testing and research.     

With its full routing flexibility, array of sound field options and multiple transducer capabilities, the AudioStar Pro is the answer for complete clinical testing of all age ranges.  Typical practice/test types include hospitals, the VA, those that conduct pediatric and CAPD testing, universities and research facilities, cochlear implant centers and private practices.    

Pello™, GSI’s one-and-a-half channel audiometer, is considered a type two audiometer.  With Pello, channel one becomes the primary stimulus channel and channel two is dedicated as the masking channel.  Channel two routing will always be opposite to channel one, with a few very specific exceptions.  Those exceptions include the Stenger test, and dichotic tests (numbers, words, sentences) found on internal word play lists or external media devices such as CDs.  

Pello is an adaptable audiometer with 4 different license options to consider.  The standard license allows for standard audiometric testing (air, bone, and speech). A license for additional speech testing capabilities, including the Quick SIN and BKB SIN, is available with “Speech Plus.”  Automatic scoring features are also available with this license. Fine frequency testing is available out to 20kHz with the “High Frequency” License, and the TEN test, pediatric noise and classic auditory tests (ABLB, SISI, tone decay) are included with the Special Tests License. Licenses can be selected based on current needs, and additional licenses may be added in the future should your testing protocols change. 

Pello has a significantly smaller footprint than the Audiostar Pro, and easier portability.  It is geared more for testing adult populations, and will typically be used in satellite clinics or private practices with emphasis on dispensing amplification.   For audiologists who test Pediatric populations, Cochlear Implant patients, and CAPD, the AudioStar Pro would be the preferred option over the Pello.

Both of these audiometers are designed smart and built strong. A complete comparison chart is available here.

How Can I Set Up an Automatic Testing Protocol with the GSI TympStar Pro?



GSI’s Tympstar Pro™ is a powerful and flexible clinical middle-ear analyzer.  Using the included configuration application (config app) can help save time by allowing multiple diagnostic and screening protocols to be created for each testing preference (examiner or patient type).   With the latest software updates to the TympStar Pro (V1.1) and accompanying config app, users will find setting up the custom protocols intuitive and easy to navigate. 

The TympStar Pro comes loaded with default parameters for automated screening and diagnostic tympanometry.  The screening protocol includes a 226Hz tympanogram and Ipsilateral reflex screening (pass / fail) at 1khz.  Additionally, there are two factory auto-sequence diagnostic protocols loaded into the TympStar Pro. Auto Sequence is initialized from the tymp test type screen and includes a tympanogram, Ipsilateral and Contralateral reflex thresholds at 5, 1, 2 and 4K, as well as Reflex Decay at 5 and 1khz.  These protocols are based on CPT codes and cannot be directly modified; however, you are able to copy them and use them as a template for creating your own custom protocols. Each practitioner can modify the protocols to preferred specifications and easily access individual preferences on the device by pressing the “Examiners” button, and then using the touch screen to select the appropriate protocol.

Customizing the TympStar Pro gives the audiologist a consistent “jumping off” point for evaluations; however, we all know things don’t always move along according to plan.  At any point in the evaluation, the examiner is able to take full manual control of the TympStar Pro and modify the parameters or sequence to accommodate individual testing needs.  With GSI’s TympStar Pro, testing and analysis of the middle-ear is efficient and precise.  From integrated and custom protocols, to advanced automatic functionality, evaluations will be quick and accurate. For more TympStar Pro tips and tricks, check out the webinar, Customizing to Enhance Efficiency with GSI TympStar Pro

How Can I Tailor Reports Based on My Testing and My Referral Sources?



Audiologists work with a variety of referral sources; everything from ENT’s, pediatricians, general practitioners to a wide array of specialty physicians.  Tailoring a report that meets each of the different protocols and referral source preferences can be a time consuming task, and sometimes hard to keep straight.  GSI Suite™ is designed to help manage test and patient data, and can save you time and help keep your reports organized. 

Suite can be used as a stand-alone software or as a module of NOAH and communicates directly with GSI’s audiometers (AudioStar Pro™, Pello™, GSI 39™, GSI 61™), middle ear analyzers (TympStar Pro™, TympStar Classic™, GSI 39), and OAE devices (Corti™). This allows you to consolidate the results of all tests you do into a patient’s electronic file.  Suite will also allow you to pull audiometric and tympanometric data from non-GSI equipment, as long as it communicates with the public databases in NOAH.  Once you have all of your test data transferred to the patient file, you can use one of 20+ GSI designed report templates, or use our powerful report writing tool to customize a report specifically for the types of tests in your protocol, or specific to the needs of your referral source.  Suite lets you organize those reports into a favorites list so that the ones you use most often will be the easiest to access quickly.  You can also use Suite to help cut down on the time it takes to write comments with a tool to manage predefined comments.  Once you have completed the report using Suite, you can save to PDF, JPEG, TIFF or XPS to email, or attach to an EMR.

Suite is powerful tool that can be customized to meet the many reporting demands that come with a busy audiology office.  To find out more, check out our webinar, Get Creative with GSI Suite.




AMTAS Flex, GSI’s self-directed screening and air conduction threshold audiometer, has multiple intended uses for a dispensing audiology practice.  In general, AMTAS Flex could be used for everything from community outreach efforts, annual audiometric testing, open houses, and walk-ins. The system itself consists of a windows based tablet, which is perfect for data management and NOAH integration, and a set of calibrated Radio Ear DD 450 headphones that are commonly used for extended high frequency testing. This makes the system lightweight and very portable.

Many independent practices develop relationships with assisted living organizations and nursing homes to coordinate things like “lunch and learns”, regular on-site hearing aid cleanings, and consultative services. Often times, free hearing screenings at regular intervals are offered where the practitioner spends a couple of hours testing residents' hearing and then advising them. With AMTAS Flex, it is possible to coordinate with the activity director to have the tablet available for a few days in a quiet room where residents could come in to take a quick hearing test at their leisure. The software uses a headphone check (to make sure the transducers are on the appropriate ear), and then instructs that patient on how to take the test with either a video or text instructions on screen. AMTAS Flex can be configured to have identifying demographics entered prior to taking the test. This allows the practitioner to connect with that resident about the results and the follow up services that are recommended. Additionally, AMTAS has an option for tests results to pop up after the test for the patient to review. It has accompanying text to help explain the audiogram and insight into their results in particular. Since AMTAS Flex runs in “kiosk mode”, at the end of test, and after results are displayed (if it is configured to include it), it will return to the start screen. It will not be possible to quit the program or get into the tablet operating system without a user name and password. Results can be printed off as a PDF (a patient report and practitioner report are available), or results can integrated into GSI suite for reporting. AMTAS Flex can also be used at places like health fairs, at bedside in hospitals, in a patient’s home, and in schools. Obviously, this is by no means an exhaustive list. AMTAS Flex can go anywhere!

There are numerous applications for AMTAS Flex in outreach efforts, and it has just as many possibilities in the office. Many independent offices are located in areas that have a lot of foot traffic and regularly have people who stop in simply because they happened to walk by. Unfortunately, they don’t always stop by when someone is immediately able to see them. Office staff can be trained to get people started on AMTAS, which can buy time for the practitioner to finish up with their current appointment and possibly squeeze the walk-in patient into the schedule so no opportunities are missed. If you have a satellite office that has front office staff, you can capture threshold or screening test data when the practitioner is not physically there. AMTAS Flex can also come in handy for up to date audiogram testing for current patients. At an annual visit, the patient could use AMTAS Flex while the practitioner checks and cleans their hearing aids, cutting down on time testing, and leaving more time for adjustments and additional counseling. AMTAS Flex can also be used for things like open houses. When targeted marketing is used to encourage people with potential hearing loss to come in and have their hearing tested, there are always those with normal hearing that stop in who are just curious about their hearing status. Starting everyone with a quick self screen can help sort out the normal hearing folks, allowing the practitioner to focus more time and effort on those with hearing loss.

AMTAS Flex is a powerful tool for a private practice, and can be deployed in a variety of creative ways. For more information visit and find out what AMTAS can do for you! 




Yes. Since the TympStar Pro was introduced, it has been capable of assessing Eustachian tube function for both intact and perforated tympanic membranes, with a work-around for performing patulous testing. With the release of TympStar Pro version 1.2, a patulous Eustachian tube test has been added as its own individual protocol with options to customize testing conditions.

Eustachian tube function can be assessed for the intact TM by obtaining a seal and running a series of three pressure sweeps with the patient drinking water between them. The TympStar Pro guides the user through the test sequence with on-screen instructions. A comparison is then made between the three peaks recorded to determine if there is a difference of 15-20 or more daPa between any of them to establish normal function. 


Cases where the tympanogram tracings are nearly identical would be consistent with Eustachian tube dysfunction.

In cases where a patent PE tube or perforation of the TM has been verified, Eustachian tube function can be established by navigating to the ETF-Perforated test protocol. In this test, pressure is now graphed on the y axis, with time on the x axis. Options for recording out to 60 seconds are available in the test setting menu. As with the intact protocol, the TympStar Pro guides the user through the testing sequence. Pressure is established and the patient is instructed to drink water at intervals, while watching for a tracing that looks like a set of stairs to establish normal function.


If the pressure was unchanged during recording it would be consistent with abnormal Eustachian tube function. 

With the recent release of firmware version 1.2, the TympStar Pro now has a dedicated test protocol for patulous Eustachian tube testing. Prior to V1.2, TympStar Pro users would navigate to reflex decay testing with contralateral stimulus selected and assess waveform morphology as the patient did a variety of respiration exercises. The contralateral probe is unplugged and/or not placed in the patient’s ear during testing, while the probe is used to establish a seal and record deflections at the level of the TM.

With this new dedicated test protocol, users will have the ability to record deflections under a variety of test conditions including Breathing Normal, Holding Breath, Breathing with one Nostril Closed, and Forced Respirations. These conditions can be customized using the TympStar Pro Configuration Application to suit individual preferences. Up to eight tracings can be recorded, with the ability to record more than one tracing under the same testing condition. Time base options extend out to 60 seconds in 15 second intervals.


Normal function is confirmed by very little change in deflection while the patient is performing the desired respiration during recording.  

A rhythmic series of deflections recorded during forced respirations for example, as pictured below, would be consistent with a patulous Eustachian tube.






The BKB-SIN is integrated on the GSI AudioStar Pro and the GSI Pello (with the Speech Plus license). The BKB-SIN is a speech-in-noise test very similar to the QuickSIN. Normative data was collected on normal hearing adults and children, using a 70 dBHl presentation level, presented binaurally. A 50 dBHL presentation level was used on patients with cochlear implants. To perform the test, press the “More” button and select “BKB-SIN”. On the display menu, select the age range of your patient to access the appropriate normative dataset. The age ranges are 5-6, 7-10, 11-14, and 15 & up (for adults). Present the sentences and score in the same way as QuickSIN. Store the results to obtain the SNR lost. The BKB-SIN can be administered to adults that might have difficulty with the longer sentences used with the QuickSIN.