The visual system and the vestibular system have strong links. If you think
about it, this makes sense. The brain needs to know where the head is in
order to know how to move the eyes. Also, vision is easier to interpret
when you know where gravity is pulling you, which is provided by the utricle
and saccule. One of the major outputs of the vestibular system is to the
visual system, via the superior colliculus (for generating saccades) and to
the motor nuclei of CN III, IV, and VI (for fixation, pursuits, and VOR).
Therapy designed to utilize the information from the vestibular system to
drive and control eye movements may enhance oculomotor control by
strengthening the connections between the visual and vestibular systems.
Although I do activities that incorporate vestibular control of eye
movements and fixation on everyone in VT, patients who experience motion
sickness can benefit tremendously from such activities. Two of them are The
Infinity Walk and what I call “20 catches” (sometimes called ‘Belgau
With Infinity Walk, the pt is looking at a stationary target or reading a
Hart Chart out loud while they walk around two crates about 6 ft apart in a
figure 8 pattern. Half way through, they turn around and go in the other
direction. (you have to actually do this to fully appreciate it, so try it
out). In one direction, your head has to spin around rapidly as you make
the corners, but in the other direction, all you have to do is turn your
head a bit to keep your eye on the target.
With “20 Catches”, the pt throws a bean bag into the air 20 times and
catches it with the other hand. While they do this, they either move their
head only and the eyes are still in the sockets, or they keep their head
totally still and only move their eyes to follow the bean bag. They then do
another 20 the opposite way. I have everyone do these two as warm ups at
the beginning of every visit.
Greenwald Eye Movements is very similar, except you use a marsden ball
swinging back and forth.
You can also find more information at www.balametrics.com and/or any related links. This site is about the products that Frank Belgau has put together.