VORTEQ™ vHIT

16 February 2022
10 - 30 mins
Reading
If you have the VORTEQ Diagnostic package, you will have license capabilities to perform VORTEQ vHIT tests. VORTEQ vHIT can provide you with useful information about the patient’s vestibulo-ocular reflex (VOR) for all six semicircular canals.

System setup

Before beginning your first vHIT for VORTEQ test, open System Default Settings from the main screen and select Head Sensor from the side panel. Ensure that the connection type is set to Bluetooth for best vHIT results. When the head sensor (IMU) USB receiver is plugged in and the IMU is turned on, the board status indicator should be green. To calibrate the head sensor for the first time, lie the IMU flat and click Calibrate Now. Make sure the sensor is completely still during this process. The calibration indicator in this screen will turn green when calibration is successfully completed. The Refresh Calibration Before Every Test option should be enabled.

Head sensor settings under system default settings. The following settings are visible: head sensor type, connection type, mount type, zero drift auto-calibration, and refresh calibration before every test. Head sensor type is set to Micromedical VORTEQ second gen. Connection type is set to Bluetooth. Mount type is set to top mount goggle. And refresh calibration before every test is set to on.

Figure 1 VORTEQ IMU head sensor setup

 

Performing the test

To begin testing, select vHIT for VORTEQ from your drop-down test menu and begin with the test for lateral canals.

vHIT for VORTEQ test options, including lateral, LARP, and RALP.

Figure 2 Test menu for vHIT for VORTEQ

Attach the VORTEQ IMU to the goggle and turn it on with the toggle switch located on the top of IMU. You will see a flashing yellow light next to the ‘on’ indicator on the IMU and a message in the side panel of the software test screen indicating that the sensor is active and ready for testing.

Man wearing VNG goggle, with red arrow pointing toward the location of the VORTEQ IMU.

Figure 3 VORTEQ IMU attached to goggle

Figure 4 VORTEQ IMU sensor ready message

If you haven’t already calibrated eyes in a previous test, it is recommended that you calibrate before starting the test. Refer to the calibration quick guide for additional details for calibration.

Once calibrated, select start from the side panel to begin the lateral test. A black dot will appear on the TV screen.

Figure 5 Start VORTEQ vHIT Test

The patient is instructed to keep their eyes focused on the black dot while the examiner performs the head impulses.

Female clinician stood behind female patient, with hands placed on the patient's jaw. The patient is wearing VNG goggles.

Figure 6 Performing the VORTEQ vHIT test

The default is set for 10 impulses in each plane. You can use the Stop button to end the test early.

 

Results

During the test you will see the eye movement tracings in red or blue and the head movements tracings in grey. If the head movement peaks in the shaded area that impulse will be accepted and added the final report. You can choose which eye is plotted using the drop-down menu located at top center of the vHIT tracings. This can also be changed in the summary screen for each canal pair.

Figure 7 Lateral Head Impulse Test

For the vertical impulses, turn the patient’s head to the side and perform the thrusts straight ahead. Arrows marked as LARP and RALP are located on the top of the goggles just lateral to the focus knob. Position the patient’s head such that the arrow for the correct canal pair is directly pointed at the target on the TV screen.

Figure 8 Guides for VORTEQ vHIT Vertical Impulses

Figure 9 Vertical Impulse Test Screens

After each subtest is complete, the vHIT graphs for that canal pair will be displayed on the summary screen.

vHIT for VORTEQ results overview, including the subtests lateral, LARP, and RALP. Each of the three subtests display results for eye velocity and position gain.

Figure 10 Completed Test Summary Screen

There are no threshold levels available for vHIT for VORTEQ tests.

 

Editing

You can edit the tracings by using the Edit Tools button to enter into the editing screen. Here you can select multiple tracings to delete or show all the impulses.

Figure 11 Edit tools

You can see a single tracing in the upper graph. You can move the black dot to change the center crossing point for the gain calculation. By default, the software will place this dot for each trace at a point just prior to the first catch-up saccade to facilitate accurate measurement of gain. You can play the video using the video playback buttons. The dashed vertical line on the graph is linked to the timing of the video.

Figure 12 Edit single tracing and playback video

 

Tip

For best results, remember to charge the IMU in between patients using the USB cable provided with the system. If Bluetooth is not connecting or if the IMU isn’t charged, you may perform wired testing using the same cable. To do this, return to System Default Settings and change the head sensor connection type to USB.

For further assistance, please refer to the Instructions for Use and Additional Information manuals, which can be accessed from the question mark icon on the main screen in the VisualEyes™ software.


Presenter

Cammy Bahner
Cammy Bahner is the Director of Audiology-Balance Division for Interacoustics U.S. In her role, she provides clinical training, education, and support for a variety of products, with a primary emphasis in vestibular and electrophysiologic assessment. She provides clinical input for the development of vestibular products. She received her Master’s Degree from the University of Nebraska-Lincoln in 1999 and her Au.D. from A.T. Still University, AZ School of Health Sciences in 2016. She has served as a guest speaker at state, national and international conventions and is a contributing author on published articles in hearing industry journals. Cammy is currently a member of AAA and ASHA.

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