Ask Ben: Making Adjustments to Eye-Tracking Devices

My mother has had ALS for over 3 years. She is unable to speak or move her muscles. She is using an eye tracking device on a trial basis. She “types” by looking at the letters on the screen, but her selections are not consistent. Are there any adjustments I can make so she can use the system better?

- Dorothy, Suffolk County

First, positioning is key. Eye-Tracking is a remarkable technology, and easy to use when set up correctly. The system must be facing perpendicular to the person’s face and eyes, and mounted at a certain distance from their face, usually around 18-24”. The adjustments needed to angle the device properly, take time, but can be the difference between success and frustration.

Secondly, it is important to be in contact with tech support of the manufacturer. Call them with a speaker phone nearby so you can make adjustments to the computer, while you are on the phone with them.

Eye-tracking, uses one of three methods to select options on the screen. Each selection method comes with its own range of adjustments.

1) Dwell (which is what your mother is currently using) requires the person to continue to look at the location on the screen they want to select. If you want to select the letter 'E' for example, you would look at the letter 'E’ for 1 second. That 1 second is called the “dwell time”, and the computer can be adjusted to accept faster or longer dwell times, depending on the capability of the individual. Since your mother is already using dwell, I would look first at adjusting the dwell time.

2) Another selection method is blink. While looking at the letter 'E', you then blink your eye (or eyes). The computer ‘sees’ the blink, and selects the letter you were looking at. This method reduces the need to continue to look at each letter (as in “dwell”), but it does require a secondary and consistent muscle movement.

3) A third method is using a switch. A switch attached to the computer, can be placed under a finger, behind your head, or anywhere there is slight movement. While looking at the letter 'E', the individual would also click the switch to select the 'E'. This method also requires a secondary movement.

Eye-Tracking works with most, but not all individuals. Even if not necessary at the time, it is useful to experience the eye-tracking process earlier than later. There are several manufacturers and they may be able to demonstrate the technology in your home. Contact me if you have any questions.

The Chapter has eye-tracking devices to loan, however there may be a wait list. I can also assist with the initial installation and set-up.

- Ben

To ask Ben a question, simply email him at blieman@als-ny.org or call at (212) 720-3057. Ben will answer all questions directly as usual, but not all questions will appear in the Monthly Update.