This post is meant for the clinicians looking for a hands-on review of audiology equipment. The first such equipment in this series is Inventis Viola, which is a portable and compact diagnostic audiometer and tympanometer combined in one.


Inventis Viola is a portable diagnostic audiology machine that combines a neat audiometer and tympanometer package into one. It comes with a fully functional ipsi and contralateral acoustic reflex testing capability. An optional upgrade is thermal printer attachment that can print audiogram, tympanogram, and reflexes.

If you are anything like me, where I have practice privileges to work through a few different clinics, this equipment will save a lot of time and place for you.  Viola can be carried around in its generous sized dedicated trolley. This ensures that the whole package is safe during the travels. Its brilliant functionality means that you do not really need to have several different packages for different machines. I fit in my video otoscope and OAE machine within the trolley too, to complete the package of hearing care. Here’s a summary of the review before I go through all its features.

Here’s a summary of the review before I go through all its features.

What’s Good:

  • Compact and portable with combined audiometer and tympanometer with ipsi/contra reflexes
  • Speech audiometry (including Quick SIN) can be run through dedicated buttons
  • NOAH compatible
  • Inbuilt flash memory to store speech in noise, and other special tests
  • Inbuilt thermal printer (optional) that can print both the audiogram and tympanograms

What can be better:

Although the machine connects to a computer to transfer audiogram and tympanometric traces by a simple push of a dedicated button, you cannot control these functions through the computer keyboard. You will still need to use the Viola keys to operate it. This is okay as the job still gets done flawlessly. You don’t really need to print the data physically if you don’t want to. Everything can be stored in NOAH electronically. However, it may be best to have both functionalities.

In the below section, I will describe the core technical functionality of the audiometer and tympanometer in this package:


Viola has a diagnostic, two-channel audiometer, which can deliver tone/speech in one ear and masking in the other via air conduction or bone conduction stimuli. The input stimuli can either be a pure tone or warble.

Audiometric frequency range is from 125 Hz to 8000 Hz with all the inter-octaves. Decibel range is from -10 dBHL to 120 dBHL. One of the nice things about this is that the intensity dial first goes up to 100 dBHL, and only when you press a button for ‘Higher dB’, will it go any louder. Not only that, anything >100 dBHL is flashed in red. Therefore, there is a double reassurance that you will not accidentally expose the client to very high dB’s. Masking noise is narrowband and is calibrated in effective masking (EM) levels.


There is a HL/UCL switch button to record hearing levels (thresholds) or uncomfortable loudness levels.

Speech Audiometry:

Speech audiometry is perhaps one of the most interesting parts of the audiometric package in this equipment. Not only there are dedicated buttons to stop/start/pause the speech audiometry, the machine will also calculate the speech recognition and Quick SIN scores automatically for you. As if that was not enough, there is a 2GB internal flash memory, where you can store all your speech material and other special tests. So, you do not need any additional hardware (CD  player or iPod etc) to perform a full range of speech audiometry in quiet and noise. In the trial mode, I stored some of my auditory processing disorder tests in the internal flash memory of my Viola and it worked perfectly well. This is such a great little feature that significantly reduces the test time and saves a lot of hassle of connecting CD player and wires etc. to the audiometer to be able to perform the testing.



Again, the output for the speech could be air or bone conduction. For input, there are five different options. There are two separate internal memory settings (INT 1 and INT 2) to play the tests via internal memory; there is a mic option to perform live voice testing; and also, there are two external input settings (EXT 1 and EXT 2) to connect CD player, iPod or the computer-based speech/music player via an auxiliary cable supplied with the package.

Audiometer also has the talkback and talk forward options to communicate with the client. Gain and monitor settings are available just in case you have to increase the level of your voice to communicate with a person with hearing problems. You can also control the calibration of speech signal via the gain adjustments.


Viola’s tympanometric abilities are equally impressive. There is a separately dedicated probe attached to the back of the machine, which serves to obtain the tympanometry results. Both the screening and diagnostic modules are available, which you can set to either start automatically as soon as you put a probe in the client’s ear; or manually by pushing the start button.

Change of pressure rate can be varied in the range of 50, 100, 200, 300 or 100-300 dapa/sec. This is quite useful, particularly for improving Glue ear cases. You will sometimes see cases where the traces will be flat as a pancake, with a screening pressure change rate of 200 or 300 dapa/second. However, when the rate of pressure change is decreased to 50 dapa/sec, suddenly a low rising peak will start appearing. I have had that sort of pattern where a good middle ear status was confirmed both by otoscopy as well as normal otoacoustic emission (OAE) testing. OAE’s are very sensitive to middle ear issues and will not be present in ears with middle ear disorders. Just on a side note-in a pattern of testing where OAE are present and tympanometry is flat- OAE are more likely to be a better indicator or middle ear health than the tympanogram.


The other cool function of the tympanometer is to change the scale of the peaked trace from auto to 1.5 ml, 3 ml or 5 ml. It comes in handy where the client has either a hypermobile eardrum or ossicular chain dysfunction where the compliance hits the roof. A normative shaded area is visible on the screen with the trace so, you can quickly eyeball if it is within normal range or not.

Acoustic reflex testing:

I found Viola very efficient in the setup and testing for acoustic reflexes. I tend to perform reflexes on every child and adult that I see in my clinics. I will at least aim for ipsi and contra reflexes at 1k and 4 khz but will perform all four frequencies if the logistics are conducive. With Viola, you can set up all the parameters of the testing within seconds. My aim is usually to see if the ipsi and contra reflexes are below 95 dBHL at 1k and 2khz. This comes from Charles Berlin’s paper where he has shown data of hundreds of auditory neuropathy spectrum disorder cases (of course, he likes to call it auditory neuropathy/dyssynchrony), and postulates that acoustic reflexes are a very good indicator of the health of the inner hair cells (IHC) in the cochlea. There are some animal studies on Cochlear Synaptopathy, which support this. Note that Electrocochleography is the only other test audiological test that can give a direct information on the health of IHC but it is much more time-consuming. Therefore, acoustic reflex testing may be used as a great screening test to know more about cochlear health, specifically, the IHC and abnormal findings on this can be further explored clinically.

With Viola, with the right setup, the required minimum testing can be completed within almost half a minute. I have included a video here to demonstrate that. This makes the whole testing very easy and efficient for the clinicians.


Reflexes can be measured either in 5 or 10 dB steps at stimulation frequencies of 0.5-4K Hz and broadband noise. The reflexes stimulation intensity can start as low as 35 dBHL and can go as high as 120 dBHL (although, I am not 100% sure if you will ever want to go beyond 100-105 dBHL in most cases). Again, a handy warning pops up in red when the intensity is >100 dBHL.


Check out this video showing a complete four frequency ipsi/contra acoustic reflex threshold testing in about 40 seconds on me. The whole thing from putting the probe in, to finish took under a minute: Click here

There are three modes available to measure the reflexes- Reflex growth intensity, so if you want to see the growth of the reflex amplitude at low and high levels. So, for me, the acoustic reflex threshold is the lowest point where a reflex is present, and 5dB below the reflex is absent and 5dB above it has increased amplitude. Therefore, you can explore your threshold in this examination mode in Viola. There is also a fixed intensity mode which you can set up if you just want to screen a client for reflexes quickly, for example, a child where you only have so many seconds of cooperation from them to sit still. Thirdly, you can use an automatic reflex threshold mode, where the start and finish intensities are chosen by you. This can be varied according to the client and purpose of the reflex testing. For example, for a client with clear symptoms of loudness growth and/or sound intolerance, you will perhaps want to keep both the start and finish dB’s quite low. A handy option in the reflex testing is to zoom on the graph when you are unsure.

One more function that has saved me a lot of time for me in those busy ENT clinics is the thermal printing option. You can store the tests in Viola as you go along and then with one press of a button, up comes the audiogram and/or tympanogram. You can also print the reflex traces too. Within seconds, you have everything available at your fingertips, nice and neat too.  Viola has helped me to see more clients within the given time but without compromising the quality of my testing.

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For my non-ENT clients, I usually save everything in my computer electronically. Inventis has its own patient management software called Daisy, that comes with the package, however, I use NOAH compatible module to store the audiogram and traces within my NOAH patient files. This works like a charm. All I have to do is connect Viola with the computer and press a ‘PC’ button to transfer all the information. As indicated above in this review, unfortunately, Viola cannot be operated by the PC keyboard. This is one functionality I will strongly recommend its manufacturer to include with any future versions.

Money talk:

The list price for the Viola range starts from an attractive £3550. Considering that it has both the audiometer and tympanometer inbuilt in one machine, it is a good value for the money package. It comes in Viola and Viola Plus models with or without the thermal printer. Thermal printer is attached to the back of the machine and makes it very slightly heavier than the one without it. It is available in the UK via Puretone Lmt. Click here to contact Puretone.