For students who face significant motor, visual, hearing, and/or other multiple challenges, or those for whom device use has not been successful secondary to access or consistency issues, flexibility of thought and knowledge of available options are required in order to determine appropriate access.
All communication relies on perception of sensory input and ability to make a physical response of some sort. When looking at an individual’s ability to use AAC to develop communication we have to be aware of how he processes input (what type of atypical patterns are used), how the individual moves (what atypical patterns exist, what movements exist to use for responding), how stable those movement patterns are, and what are the effects are of position stability, motivation, other impairments.
Many of these children are caught even more tightly by the “Catch 22” (Porter) for individuals who require aided modes of communication:
- Aided language does not naturally exist in the environment
- The individual cannot spontaneously “uptake” something that is not there
- Professionals intervene based on their perception of what’s possible
- The individual can only demonstrate what’s possible based on what’s been set up to use
Once again, aided language stimulation is a necessary ingredient in the individual's environment for him to be a successful communicator. As he responds to what’s provided the assessment can continue. Dynamic assessment is necessary in AAC. We intervene -> observe -> intervene -> observe (Porter 1997).
Alternate Ways to Respond to AAC Systems
Modified direct access:
Such as a head pointer, mouth stick pointer, eye gaze (all low/no tech)
Partner assisted scanning (PAS):
Uses partners who have been specially trained for interacting. Partners show, point, and/or speak each item.
Eye gaze systems:
Can range from no-tech to the ultimate high tech. Here is a set of eye gaze boards you can try.
Head mouse, head tracker, joystick, mouse emulators:
Modifications on direct selection using infrared beams or computer access modes. The head tracker is more tolerant of head movement than eye gaze technology systems, but shows greater fatigue.
Use of key guards to count spaces as a tactile guide to the display:
Requires memorizing the displays and sequences.
Switch/scanning:
The slowest way to access an AAC system.
The specific motor impairments of the AAC user need to be assessed and catalogued. What are the effects of muscle strength, symmetry of body, disassociation, ATNR (asymmetrical tonic neck reflex) weight bearing and shifting, eye-hand coordination? Know whether shoulders are forward, elbows flexed or extended. Determine the ability to grasp a target or use vision. Know if there is increased response time. Determine the available movement pattern.
A variety of body parts can be used to activate switches. Head switches can include toggle-type switches, button-type (such as Jelly Bean and Buddy Button), head, chin, and tilt switches. The Sip ’n Puff switch is used in the mouth. There are also foot switches and eye blink switches. Some very sensitive switches can be activated by very minimal muscle movement. For using the hand, beyond standard button switches, there are finger, thumb, and pinch switches, as well as switches that use hand grip.
For some users the size of the target area is crucial. Some individuals need a larger switch for consistent access, such as Jumbo and Saucer switches.
For other users the range of motion needed to find and hit the switch is of utmost importance. Switches that work well with individuals who have limited range of motion or limited fine motor skills include the Twitch, Finger, Compact, and Gumball switches.
For users who require sensory feedback from the switch there are switches that provide vibration, textured surfaces, lights, or music. For users with visual impairments there are switches that offer color, contrast, lights and vibration.
There are a variety of access possibilities. It takes time, knowledge of the individual, and knowledge of his communication needs and environments.
Try everything, and Keep on Talking.
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