Home OKN (Optokinetic) Task for Habituation

Timothy C. Hain, MD of Chicago Dizziness and Hearing. •Page last modified: March 9, 2022

This page provides suggestions for use of a program (i.e. web page) to produce a home OKN task, that can be used for home treatment. There are many other methods of doing the same thing, such as using "youtube" videos of OKN stimuli.

This page is to help patients of Chicago Dizziness and Hearing, with MdDS, who have been asked to do home treatments for MdDS with the Roll habituation protocol. If you are not a patient of Chicago Dizziness and Hearing, while we provide this material, please do not contact us with questions -- these should be addressed to your own health care provider.

The original home OKN task protocol is shown below in figure 1 from Dr. Dai's paper. (From Dai et al, 2014)

treatment paradigm
Treatment Paradigm (From Dai et al, 2014).

There are two methods of doing this task at home- -using a large video monitor and your PC, or using a combination of your cellphone (only Apple is supported right now), and an "app" called the Fushiki ETTOKN, and a 3rd party VR headset such as can be purchased at Amazon for about $40. The general methodology is the same for both the VR method and the large monitor. The main constraints on the headset is to find one that is comfortable and also that has a wide field of view.

We want to be clear that while Dr. Dai's protocol has been studied and reported on in several research papers, these home protocols (which attempt to copy Dr. Dai's protocol), have no evidence base that supports their use. There is no reason to think that they will make you worse, but still note that use of this visual treatment is at your own risk.

How to configure the "app"

The Apple "app" is called Fushiki ETTOKN (after the leader of the lab in Japan that developed this program). It can be found on the iphone "app store" by searching for "Fushki ETT video", and currently (i.e. as of 3/2022) is offered for $24.99 US. Download it, run it, and click on the "Gyro" button. While looking at your cell-phone straight on, turn it about the front-back axis (i.e. rotate it). The stripes should counter-rotate so that they always remain upright. This is the way to use it. The goal is to create "vection" -- a sensation of turning rather than a feeling that the stripes are moving. This works best with the stripes moving at the lowest rate, and with the finest lines -- not the big ones.

Once you have it set up, insert into the VR headset.

Which direction ? we suggest alternating direction - -one day to the right, the next day to the left. If you find that one direction makes you worse, switch to the other. A study suggested that the direction doesn't matter (e.g. Mucci et al, 2018)

Perform the Home OKN task for a week.

The original protocol was done 4-5 times/day, for 10 minutes a session. To copy this, you might do this on the hour, for a half-day, if this is feasible. Why ? -- well in theory, "Batching" -- lots of sessions in a short period of time, are better than spacing things out (e.g. once/week). This is the way it is done in the aerospace field when treating motion sickness.

While watching the Home OKN task on a large monitor or through the Apple ETTOKN "app", rock the head about the front-back axis (i.e. roll axis, see figure above), about 15 degrees to the right, and then 15 degrees to the left. The frequency should be slow -- roughly one full cycle (i.e. left to right and back) every 2 seconds. The goal is to rock the head at the same frequency that you feel you are rocking.

Note: The Home OKN task runs "in the browser", and as one might be using different browsers, it can run differently depending on the browser you use to view internet material. We usually use Chrome. It also runs in firefox, opera, and Edge. Edge has a problem with the right edge being chopped off -- evidently an Edge bug.

From the Dai papers, the the frequency of the head rocking was recommended to be the same as your inner rocking -- this is usually about 1/5 cycle per second -- or in other words, to one side for about 2.5 seconds, and then to the other side for about 2.5 seconds (or a little more). Adjust it to your own timing.

The direction of the OKN task probably should be in both directions. The only study done suggested direction didn't matter. (e.g. Mucci et al, 2018)

For the computer version, use as large a screen as available, and sit as close as you can without causing blurring to make the OKN stimulus fill your visual field. For the VR app, adjust the headset to get it in focus and to make it as large as posisble.

We think it is best to remain off of medications in the "valium" family such as valium (diazepam), klonopin (clonazepam), Ativan (lorazepam), and Xanax (alprazolam) while doing this protocol, as these medications are thought to block adaptation in animal models. In fact, if you can withdraw these medications for several weeks, this would probably be best.

Some comments about "do it yourself versions".

One might wonder whether or not just doing the "home version" of the OKN habituation task, might not be a reasonable substitute for for the more difficult office version, that requires staying at a hotel near Mt. Sinai hospital in New York.

At this writing, we just don't know. Dr. Dai and associates reproted that the office version works most of the time. So far, nobody has studied the home protocol.

There are several differences between the home and office habituation methods - -

Other OKN tasks such as "youtube" video's, etc may work as well, but we have not tested these out. We think that small displays (such as cellphones or Ipads) would likely be inferior to large displays (such as TV sets), but with a VR head-set, this problem is eliminated. As VR headsets are head mounted, an "OKN" video from Youtube would not replicate the stimulus, and we are dubious that it would work.

We have been told that a "short throw video projector" is the optimum method of presenting this OKN stimulus. We have had no direct experience with this. We would think that a large display would be better than small displays, but as mentioned above, the VR headset method may get around this.

References:

Appendix:

Variant OKN drivers:

We have developed other variants of the driver program for OKN that you can experiment with:

The arrow keys control both the speed and direction. Press the left or right arrow key to start it moving. The vertical arrow keys work for some of these stimuli (i.e. Checkerboard, Random stars). We do not know if these stimuli are helpful or harmful. They are just there for your viewing enjoyment, and use at your own risk.