2004 Conference Proceedings

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UNUSUAL ACCESS METHODS

Presenters
Gaylon Ponder-AAC Consultant
Words+, Inc.
1220 West Avenue J
Lancaster, CA 93534
Phone: 800-869-8521
Fax: 661-723-2114
Email: sheron@words-plus.com

Ricardo Ortega
Words +, Inc
1220 West Avenue J
Lancaster, CA 93534
Phone: 800-869-8521
Fax: 661-723-2114
Email: sheron@words-plus.com

This paper is intended to increase the awareness of "unusual alternate access methods" and provide guidance as to when to consider using them.

Common Access Methods

The most common assistive technology access methods work well for many but not for all, all persons with disabilities. Those few for whom they don't work could benefit from other more appropriate access methods:

The Problems

Two inherent problems often exist. The direct access, mouse, and head pointing methods require fine motor skills. Taking the case of Athetoid Cerebral Palsy (CP), the original problem is poor fine motor control, and methods that use fine motor control cause fatigue.

Another common problem is the build up of tone and spasticity. Single Switch Scanning offers relief from this tone, spasticity, and fatigue by allowing the user to use gross motor movements to press, or hit, a switch at the appropriate time; but it has its own limitations. The most obvious one is the requirement to hit the switch at just the right time. The exact timing requirement often leads to increased tone and spasticity; especially when the user is trying to work fast, such as during testing or when operating under anxiety.

Another often overlooked limitation of single switch scanning is the repetitive use injury problem. Picture the person with Spastic Athetoid CP who uses a head switch which require three movements of an eleven pound head for every character selection. In time the muscles will strengthen on that side, the ligaments will shorten, the spinal column will curve in that direction, and the client will suffer health problems related to the activity. We are all warned that improper overuse of single muscle groups can cause repetitive use injuries.

Problems with words or word selection are also fairly common as when the augmentative communication user either selects the wrong word, or misspells it, or inadvertently leaves it out of the sentence entirely. Often even the wrong word is in the sentence. You can see the surprised look on the client's face when it doesn't say what was intended. The problem is visual load.

With any of the access methods listed above, the client is busy looking at the access method. Examples are:

Note that none of these visual activities are required of those who don't need special access techniques. We can just watch what we type on the screen and edit it as we go. Using the common access methods listed above, however, the client can't properly edit while accessing. When they have time, they look at what they thought they typed, and it is often too late. The result is that others may perceive them as less capable when, infact, they are often just too visually loaded due to the access method.

Problem summary in order of occurrence during normal operation:

Alternate Solutions

There are two alternate methods of access that overcome some or all of the problems noted above. As with any access method they have their own set of limitations, but in many cases they are much better than the more commonly used methods. Also, they often work when the more common methods fail completely.

Please take time to become "familiar" with them so they can become a part of your arsenal of solutions. They are not difficult, and in many ways are easier than the commonly taught methods. They are almost always easier for the user if they are introduced to them before he or she becomes engrained in the use of another method. Both of them utilize two switch access. One is called Two-Switch Row Column Scanning, and the other is called Two-Switch Morse Code.

Two-Switch Morse Code

Morse Code is covered first because it is so powerful. In order to make a letter in Morse Code the client must learn the code. It is unbelievably easy. For instance, an "e" is one switch hit, so is a "t". Morse Code is nothing more than a different way of writing a letter. In Two-Switch Morse Code one switch sends dots, and the other sends dashes. In order to make an "e" you have to hit the dot switch one time - pretty easy compared to what we had to do to learn to print an "e" with a pencil. A "t" is the dash switch one time. Two dot switch hits is an "i" every time. Three dot switches yields an "s" every time. We learned 26 complicated ways of making letters on paper when we were little kids. In Morse Code we ask the client to learn 26 simple ways of making letters, and provide an easy way for them to do it. The access is direct select without the fine motor and visual load. The client does not need to watch the scanner, or the keyboard. They have to hit switches in the correct sequence within a certain time frame, but not at a specific time. The client using Two-Switch Morse Code has the visual freedom to watch the word prediction box and edit the work in progress. Morse Code is the access method of choice for the blind person who can't use a keyboard.

As an added bonus, in Two-Switch Morse Code the mouse movements become very easy. For Instance:

These all require only one switch hit because if you hold the button down it will send repeated dots or dashes at the rate selected. If gross motor skills don't allow the client to hold the switch down for repeated dots, they just keep hitting the switch until it has beeped the correct number of times.

A small child who can hit a switch and count to five can run the mouse in Morse Code without having to learn switch scanning.

By using Two-Switch Morse Code the user uses two sets of muscles instead of one, thus dividing the muscle load. The muscle load is cut in half again because the switch can be held down for repeated dots or dashes. The average is two switch hits per character rather than three hits that are required with single switch scanning. Spasticity, tone, and fatigue are reduced because exact timing is not required and the fine motor load is reduced.

Morse Code benefits:

Limitations:

Two-Switch Row-Column Scanning

Two-switch Row Column scanning is simple but rarely used. One switch becomes the "stepping" switch, and the other switch becomes the "select" switch. The client presses the "stepping" switch to step through rows until the correct row is highlighted. Then the "select" switch is pressed once to select that row. Next the "stepping" switch is pressed to step to the correct column. The "select" switch is then pressed to select the character or symbol.

This process eliminates the exact timing that is required by single switch scanning, releasing the tone, spasticity, and fatigue so the client can be more successful. The scanner is "driven" by the client rather than the client being "driven" by the scanner. The load is divided between muscle groups, and doesn't require fine motor control. This method still requires considerable visual attention, but it can be useful in preparing a user for Morse Code by letting the user get accustomed to using two switches.

A common error is for the assistive technology specialist to decide that the person can barely operate one switch, and could never do two switches. Try before deciding. Make the easiest switch the stepping switch, and the more difficult one the select switch.

If you need assistance in applying or understanding these alternate access methods, call Words+ and we'll be happy to assist you.


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