Vestibular Rehabilitation Therapy
Visual Dependence training
This page is primarily intended to be a reference for patients
who have been referred for therapy for visual dependence.
Timothy C. Hain,
Page last modified:
February 8, 2018
Visual Dependence Exercises
It is not unusual for vestibular therapists to propose "interesting"
treatments. For example, therapists might have patients smear their
glasses with Vaseline. The rationale is to reduce "visual dependency",
which is an inappropriate reliance on visual input, in situations where it might
be better to use somatosensory or vestibular inputs. In certain situations,
this seems like a good idea.
Does smearing vaseline on glasses reduce visual
dependency ? Nobody knows. If we had a reliable method of measuring visual dependence,
perhaps we could relate it to interventions. At this writing, posturography
seems to be the closest to being a measure of visual dependency, but it is somewhat expensive and many health insurances refuse to pay for the testing using this expensive device. Cheap, quantitative and reliable methods are needed to measure visual dependence.
Virtual reality training (see here) might offer a method
of reducing visual dependency. This promising technology is in its infancy
right now, and research studies are needed to validate it. Right now, the equipment is expensive but it is rapidly getting cheaper.
At our practice at Chicago Dizziness and Hearing, we have a vestibular physical therapist with the proper equipment for this activity (i.e. driver simulator software, full field visual stimlus).
Visual dependence training with a stationary anchor.
We proposed (Chang CP, Hain TC. "A theory for treating visual vertigo due to optical flow" CyberPsychology and Behavior. 9-2007), a theory for treating visual dependence. The essence of this idea is that, unlike the usual paradigm used in virtual reality training, it might be better to combine a gradually increasing, central moving field with a surrounding visual surround. The availability of both a "visual anchor" as well as a destabilizing input, might allow the health care provider to gradually recalibrate a person's oversensitivity to optic flow.
Visual dependence training is a mixture of the gaze-stabilization protocol and balance exercise protocol, but with a greater emphasis on suppressing abnormal visual input in real-life situations.
- Visual stimuli
- Eyes closed (this is for practice of mental imagery)
- Blank background
- Busy background (i.e. checkerboard)
- Very busy background (i.e. grocery store).
- Very busy moving background
- windy outdoors,
- watching waves come in
- Disco-ball type stimulator (usually only available in a medical office), we use a an array of video monitors in our office. This is a link to the program for practice patients (optokinetic). The arrow bars control the speed.
- Visual surround type video games such as driving simulators. Here it is best to hook your computer up to a large screen TV, and aim to build up to 30 minutes of exposure/day. There are many suitable stimuli on this page:
- Misleading background
-- this is the main exercise.
One does not have to do all of these.
See the commentary above concerning use of a visual anchor. There are many suitable stimuli on this page:
- walking with a crowd
- walking against a crowd moving the other direction,
- rotating visual surround such as a disco-ball or optokinetic stimulator (optokinetic).
- twisting golf umbrella
- x2 exercises - -where head and target move in different directions
- x0 exercises -- head and target move together
- Environmental contexts with strong visual inputs
- Driving, in broad daylight, evening, dark, sleet/rain. There are many suitable stimuli on this page:
- Going to the grocery store. There are many suitable stimuli on this page:
- Going to the movies
- One combines the other sensory stimuli outlined in the other protocols to make this more difficult. For example, walking on sand at the beach, with head rotating back and forth, with the waves coming in.
- By using cross-axis stimulation - -i.e. moving the head one way, while the visual surround goes another way, one can habituate the system. This is the principal used for our home-roll paradigm for MDDs.
Heavy exposure to
optokinetic stimulation does not have a strong effect on either optokinetic
nystagmus (OKN) or circularvection (McDermott et al. 1999), but it may be helpful
in visual dependency.
No studies are available regarding the effect of medications on this type of protocol. This reflects the author's experience and "common sense" neurophysiology.
- Sedatives should be avoided (such as valium type medications (e.g. klonopin and Xanax), antihistamines, and "phenergan" or "compazine").
- Activating medications such as caffeine and/or venlafaxine may be helpful.
- Ondansetron can be used for nausea.