Refixation Saccade

Hi, I’m Dr. Jared Nielsen. I’d like to talk to you about brain and brain recovery. When we look at the brain and we’re focusing on our brains ability to be able to perceive and heal, we often use a test called an optokinetic strip or refixation saccade.

What we mean by this is actually the eye’s ability to find a point, hold that point, and follow it through a field of view. Let me describe it this way, a region in our brain called the frontal lobe actually finds a target and then pulls that target across our field of view. The point across is by the parietal lobe of the brain.

A target where our eyes will look to the target and then pursue across is called a refixation saccade. That marries the hemisphere on the same side of the brain. We can actually look to the target frontal lobe, pursue that target across our field of view, parietal lobe and then find the refixation again. That’s the refixation saccade.

We’ll demonstrate this today and show the application of it when we’re trying to assist someone in recovering the brain. The reason that I’d like to discuss this is, so often we see people with iPads, or some type of a mobile device, where they’re following through, or looking through either an application, or an app, or they’re actually looking for photos, or something where they continually sweep one direction.

If there’s been a brain injury, or a disconnect in the brain on one side or the other, that constant flipping or following motion may actually create a disparity in the brain. We have horizontal refixation saccades, and we also have vertical refixation saccades.

The horizontal saccades actually calm down the parasympathetic nervous system, whereas vertical saccades can activate the parasympathetic, or sympathetic nervous system which then we look together as the autonomic nervous system.

We also look at vertical saccades, so the up and downs, as a means of indicating our sense of anterior or posterior sway. Let me say that a different way. When we look at our center of gravity when we’re standing, our bodies will either move forward or backwards subtly, depending upon an injury to the brain, or changes in metabolic rates of the brain.

When we see that, particularly in patients who have had a demise in their dopamine production, a person for example with Parkinson’s disease, will feel as if they’re falling backward and in order to overcome that, begin to lean more and more forward in an attempt to overcome that sense of falling.

When we look at that person, the more that their head tips forward, the eyes will actually go upward, but it’s actually resisting a posterior fall, or a downward movement of the eyes. As we take that optokinetic vertically it actually will take for us, or increase the sense of moving forward for them, to change that perception of sway forward or back.

This has a great application also for people with shin splints, and also an application for people with plantar fasciitis. If a person feels like they’re falling backward their feet will in essence, clod the ground creating tension on the foot, or the plantar fascial portion of the foot, and create then potentially that pain. Another thing that can happen is, if a person is falling strongly forward their feet will press back and they’ll develop anterior shin splints.

As we look, the application even for a student athlete, or if you’re a runner, someone who’s active, and you observed one of those two conditions, it may actually be your center of gravity, or what we call pulsion, or retropulsion, or anteropulsion, or center of sway, or center of gravity.

We can actually help the body to correct that if I feel like I’m falling backward, my feet will claw the ground. The manifestation is going to be a sense of plantar fascial pain. We’ll actually use then, a movement in the opposite direction. If my eyes are going downward as I feel that I’m falling backward we’ll actually draw the optokinetic upward.

If we feel like we’re falling forward, we’ll resist back, we develop anterior shin splints. In that case then, falling forward the eyes will go upward, we’ll actually draw the optokinetic downward, or the refixation saccade.

As you contemplate where your brain is and the health of your brain doing things that may have an application upward continually, or downward continually may actually make your symptoms worse. If you’re going side to side and only putting the direction that is over stimulating your brain in the wrong direction, you may notice a sense of dizziness. Be aware of this as you use applications on your mobile device, it may not be helping you to heal.

I’m Dr. Nielsen. I hope this is a help to you.

Video production by Cocoa Productions