Potential for Eyegaze use based on client's medical diagnosis
The client's medical diagnosis may also provide considerable help in pre-determining the likelihood of successful Eyegaze operation. Using medical diagnosis as a starting point, click on the diagnosis to learn what conditions may exist that may affect optimum Eyegaze operation:
- Amyotrophic Lateral Sclerosis (ALS)
- Brain Injuries
- Cerebral Palsy
- Multiple Sclerosis
- Muscular Dystrophy, Spinal Muscular Atrophy, Werdnig-Hoffman Syndrome
- Rett Syndrome
- Spinal Cord Injuries
- Strokes
- Amyotrophic Lateral Sclerosis (ALS):
People with ALS are generally very successful operating the Eyegaze Edge. We have, however, seen limited eye movement in a few people with ALS, which made it difficult or impossible for them to perform the more complex Eyegaze functions, such as typing, on traditional direct-select Eyegaze keyboards. Several Eyegaze keyboards designed for users with limited eye movement are now making it possible for most users with ALS to continue to operate the Eyegaze Edge indefinitely. A common problem for users with ALS is dryness of the eyes. The corneas are normally moistened by tears, which are spread around by blinking. As the blink reflex decreases, the corneas dry out, and don't reflect infrared light very well. The Eyegaze Edge needs to see a corneal reflection in order to function. Over-the-counter artificial tears eye drops will typically solve the problem of dry eyes.
- Brain Injuries:
Traumatic and anoxic brain injuries can result in a variety of problems that may have an effect on Eyegaze operation. Cognition, memory, concentration, or even the ability to read may be affected by the injury. Vision problems are also common. In general, if the person has a consistent way to communicate yes and no, we assume there is a level of cognition that is sufficient for some Eyegaze Edge use. Often memory and attention problems become apparent during the process of evaluating the user with Eyegaze. Vision problems such as diplopia, blurred vision, alternating strabismus and homonymous hemianopsia may also impede Eyegaze use. Cranial nerve damage may limit the user's ability to control his eye movements. There are several adjustable parameters within the Eyegaze Edge that can be changed to accommodate limited eye movement.
return to top - Cerebral Palsy:
People with severe cerebral palsy who are able to maintain a stable head position, either on their own or supported by a head rest, and who do not have significant eye control problems, often do quite well with the Eyegaze Edge. A number of children with cerebral palsy are currently using Eyegaze Systems to participate in school, from kindergarten through college. People with CP who have uncontrollable head motion may not find Eyegaze operation acceptable, since the Edge camera has a limited field-of-view. Because controlling the eyes does not elicit a movement response in the body, many people with CP are proficient Eyegaze users. The Eyegaze Edge re-acquires the user's eye in 1/30th of a second if he moves out of the field of view and returns. A variety of eye control problems are also often associated with CP, most commonly alternating strabismus. Applying a nasal-side patch to the eye that is not being tracked may solve the problem.
- Multiple Sclerosis:
This disease does not, in our experience, cause any physical limitations that prevent the Eyegaze Edge from tracking the eye. However, if the multiple sclerosis has affected vision, the user may not be able to see well enough to read the screens, even though the Eyegaze Edge can track his eye just fine. A simple way to determine the presence of this type of vision problem is to position the potential user about 24 inches away from any standard color computer monitor and ask him if he can read typed text on the screen. Additionally, people with MS who have taken steroids may have cataracts, a common side effect of frequent steroid use that can interfere with Eyegaze use. If the catract is removed the Edge will typically track the user's eye with out difficulty.
- Muscular Dystrophy, Spinal Muscular Atrophy, Werdnig-Hoffman Syndrome:
All are typically good users. - Rett Syndrome:
After evaluating several dozen girls with Rett syndrome we have not determined any predictors for successful Eyegaze use. Many of the girls were too easily distracted to use Eyegaze in any meaningful way, although they were able to calibrate without difficulty. There is currently one Eyegaze user with Rett syndrome.
- Spinal Cord Injuries:
Quadriplegia resulting from spinal cord injury presents no limitations for Eyegaze operation. The system is often an excellent tool for people who are ventilator-dependent and quadriplegic, especially if they are non-verbal. It is also being used by some people with spinal cord injuries who are verbal, or who are able to move their heads, but find direct-selection with the eyes a faster and easier method of computer access than alternative methods of row/column scanning, voice control, or mouth or unicorn sticks.
- Strokes:
Brain attacks in the pontine (brainstem) region often result in "locked-in syndrome", leaving the person cognitively intact but with no means of communication other than with the eyes. Concurrent cranial nerve damage can affect the eyes as well, often limiting horizontal eye movement. Many people with brainstem strokes are able to operate the Eyegaze Edge in spite of some limitations in eye movement, although it may be somewhat more difficult for them to do than it is for someone with full eye control. Several adjustable parameters within the Eyegaze Edge can be changed to accommodate eye control deficits commonly associated with strokes. One Eyegaze user who is locked-in has written and published two books in spite of some limitations in eye movement.