MD ent surgeon and neuro-otologist Søren Hansen, speaks about ICS Impulse

Read what other users are saying, and learn how ICS Impulse is changing vestibular testing – User Testimonials

Dr Anirban Biswas says:

This is impressive but how does differ from the SYNAPSYS VHIT and how much more helpful is it. What flaws of the SYNAPSYS machine can be overcome by this ?? Please elaborate as I am asked this question in some forums by ENT doctors. I have the SYNAPSYS system a but would like to go in for this too

  • Søren Hansen, MD says:

    I have used the Synapsys VHIT for 4 years and the ICS Impulse for 1 year now. There is definite some disadvantages using the Synapsys VHIT system in comparison to the ICS Impulse test. Using the Synapsys VHIT system you are performing the tests with a fixed camera in front of the patient. To my impression, the Synapsys system works fine testing the lateral canals because the distance from the high camera to the patient’s eyes are constant but there is a major problem testing the vertical canals (superior and posterior canals) because you are moving the patients head closer to and further away from the high speed camera. In my impression, the picture gets blurry testing the vertical canals using the Synapsys system and I haven’t been able to make any clear judgment on the vertical results. I simply cannot say that I can focus on the pupil and be sure to get a trustworthy result testing the vertical canals – retesting gives different results every time according to who is testing.
    I found that using the ICS impulse gave me a faster, very clear and precise result testing all the canals, I really like the 3D representation of the results and I found myself using the ICS Impulse on all my patients. The ICS Impulse is reliable and very fast using in normal clinical settings.

    Soren Hansen, MD
    ENT surgeon and Neuro-Otologist
    Copenhagen Denmark

    • Wendy Crumley-Welsh says:

      Earth mounted cameras (i.e. Synapsys system) cannot distinguish between head rotation (movement around a fixed point) and head translation (movement with no fixed point). The Synapsys to our knowledge was using 100 Hz camera but no matter which camera is used it will have lower resolution than Impulse because they have to use a lot of image to track head.
      The eye position measurement relies on accurate head position measurement and errors are cumulative if you have head translation occurring.
      We use all our camera resolution to track the pupil and we measure head independently with gyros that are very accurate especially for velocity (Synapsys does not measure velocity but instead uses eye position shift in gaze) and our method is not confused by translation.

      Wendy Crumley-Welsh, Otometrics
      ICS Impulse Product Manager


The test re-test reliability is very good for the horizontal canal tests using the SYNAPSYS system of VHIT but the testing of the vertical canals -anterior and posterior needs a bit more of perfection, no doubt I have had problems with these canals and test re-test does not always tally for anterior and posterior canals. I was blaming my technique for it. Head translation is probably the offending culprit (and probably not my technique) during the vertical canal tests.
I have ordered the OTOMETRICS head impulse system (but am yet to get it)also and hope to have better luck with the vertical canals

Dr Anirban Biswas
Kolkata, India


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