Dynamic Visual Acuity (DVA)

15 February 2022
10 mins
Reading

What is the Dynamic Visual Acuity (DVA) test?

The Dynamic Visual Acuity (DVA) test is a behavioral assessment of the Vestibular Ocular Reflex (VOR) function in response to functional head movements.

List of protocols available in the VORTEQ Assessment bundle, including the following: spontaneous nystagmus, video frenzel, dynamic visual acuity, Dix Hallpike advanced, and lateral head roll.

Figure 1 License for Video Frenzel and VORTEQ Assessment bundle.

 

Calibrate TV screen

Be sure to set your TV size and patient distance in the System Default Settings set up before beginning the first test.

System default settings for DVA stimulus. The following options are available, using inches when applicable: boundaries width, boundaries height, patient distance, option to show or hide boundaries, and select monitor. In the select monitor option, display 1 and display 2 are available to choose.

Figure 2 System Default settings TV set up for DVA

 

Performing the test

To begin testing, select DVA from your drop-down test menu.

Drop-down test menu, including Dix Hallpike left, Dix Hallpike right, headshake, spontaneous nystagmus, and dynamic visual acuity. Under dynamic visual acuity, there are five available options: static acuity, right, left, down, and up. Static acuity is highlighted in yellow.

Figure 3 Test menu for DVA

You will be reminded to make sure you remove the VORTEQ IMU from the goggles and attach it to the headband.

Figure 4 (a) Reminder to put the VORTEQ IMU on the headband and (b) Patient wearing DVA headband and being tested

Once the headband is mounted on the patient you can hand them the remote control. The patient is instructed to press the arrow that matches the direction of the optotype they see during the testing.

Woman holding remote control for DVA test. The left, up, right, and down buttons are labeled, which can be found in the left, up, right, and down positions, respectively.

Figure 5 Remote Control for DVA Test

The choices are up, down, left or right. If they are uncertain, they are to take their best guess at the direction that think the optotype is pointing.

 

Static Visual Acuity

 

1. Performing the test

For the static acuity test the patient keeps their head still and responds to the direction of the optotype that appears in the white square on the TV screen.

You will see this test screen.

Target presentation is set to automatic. The optotype is pointing downward. Below, there is an empty graph with visual acuity as a function of head velocity.

Figure 6 Static Acuity test – clinicians screen

When you press start you will be able to see the optotype direction that the patient sees and also the button that they are pressing.

 

2. Results

When the test is completed you will see the patient’s static acuity score.

Graph with visual acuity (logmarithmic) as a function of head velocity. The patient's static acuity score is minus 0.3 at a head velocity of 0 degrees per second.

Figure 7 Static Visual Acuity results

 

Dynamic Visual Acuity

 

1. Performing the test

You are now ready to begin the dynamic visual acuity testing. You will instruct the patient to move their head to the beat of the metronome. You can guide them or move their head for them if they cannot manage to stay in the green shaded area. The optotype will not appear if the patient is moving their head too slow or too fast which is shown shaded in red.

A single-axis, horizontal graph, ranging from 0 to 225 degrees per second. The proper head speed range is marked with two grey lines, and is between 100 to 150 degrees per second. The head speed in this instance is just above 100, indicated by a portion of the bar highlighted in green between 100 and 150.

Figure 8 – Proper head speed

A single-axis, horizontal graph, ranging from 0 to 225 degrees per second. The proper head speed range is marked with two grey lines, and is between 100 to 150 degrees per second. The head speed in this instance is just above 150, indicated by a portion of the bar highlighted in green between 100 and 150, and a portion of the bar highlighted in red between 150 and 225.

Figure 9 Head speed too fast

 

2. Results

After you complete all four runs (left, right, up, down) you will see a summary graph of the patient’s dynamic visual acuity for both horizontal and vertical eye movements.

Summary screen for the dynamic visual acuity test. Target presentation was automatic. The following subtests were completed: static acuity, right, left, down, and up - marked with green checkmarks. Two graphs with visual acuity as a function of head velocity display the following results. Static visual acuity is -0,3 at 0 degrees per second. For left and right moving, the dynamic visual acuity is -0,3 at 100 degrees per second. For down and up moving, the dynamic visual acuity is -0,3 at 75 degrees per second.

Figure 10 Completed Test Summary Screen

There are no suggested thresholds provided as a default. You can however choose to add your own suggested thresholds. If you provide your own thresholds, then any data points falling in the grey shaded areas would be outside of the suggested normal threshold ranges and indicate that the patient has trouble staying focused on that target at this head speed.

For further assistance, if needed, please refer to the Instructions for use and Additional Information manuals.


Presenter

Michelle Petrak
Michelle Petrak, Ph.D., is the Director of Clinical Audiology and Vestibular Research for Interacoustics. Her primary role is development and clinical validation of new technologies in the vestibular and balance areas. She is located in Chicago where she is a licensed private practice clinical audiologist at Northwest Speech and Hearing (NWSPH). Dr. Petrak received her doctorates in Electrophysiology (1992) and Biomolecular Electronics (1994) from Wayne State University and her Masters in Audiology in 1989. Her special areas of expertise include vestibular and balance assessments and management of the dizzy patient. Dr. Petrak is involved with new innovative product developments, clinical evaluations of new protocols, and publishing, teaching, and training on the management of patients with dizziness. She continues to lecture extensively nationally and internationally, and she has numerous articles published in the hearing industry journals. She also participates on the committees for several doctoral students as support for the research projects.

Popular Academy Training

Interacoustics - hearing and balance diagnosis and rehabilitation
Copyright © Interacoustics A/S. All rights reserved.